WorldWideScience

Sample records for bauxite

  1. Bauxite and alumina

    Science.gov (United States)

    Bray, E.L.

    2012-01-01

    The United States is import-reliant for nearly all of the bauxite that it consumes. Small amounts of bauxite and bauxitic clays are produced in Alabama, Arkansas and Georgia for nonmetallurgical uses. Metallurgical-grade bauxite (crude dry) imports in 2011 totaled 9.54 Mt (10.5 million st), 18 percent more than the quantity imported in 2010. Jamaica (54 percent). Guinea (25 percent) and Brazil (18 percent) were the leading suppliers to the United States in 2011. In 2011,117 kt (129,000 st) of refractory-grade calcined bauxite was imported, a 69-percent decrease compared with imports in 2010. This decrease was partly attributed to an increase in net imports of refractory products such as bricks and crucibles, which were 39 percent higher than in the prior year. Imports of refractory-grade calcined bauxite from Brazil declined by 99 percent and by 75 percent from Greece. Restrictions on exports of raw materials from China also might have contributed a small amount to the decrease in imports. Imports from China declined by 45 percent. Guyana (42 percent), China (35 percent) and Greece (22 percent) were the leading sources of U.S. refractory-grade calcined bauxite imports. Imports of nonrefractory-grade calcined bauxite in 2011 totaled 236 kt (260,000 st), 23 percent less than the quantity imported in 2010. Guyana (51 percent), Australia (37 percent) and China (7 percent) were the leading sources

  2. FOUR CENTURIES OF BAUXITE MINING

    Directory of Open Access Journals (Sweden)

    Rikard Marušić

    1993-12-01

    Full Text Available In the paper the results of many years of archival and field investigations in the history of bauxite mining of the three authors are presented. It was established that in Istria in the valley of the river Mirna beneath the Castle of Sovinjak bauxite was exploited already 400 years ago, and that 1808 about this ore the first scientific account was published. Accordingly, the statements in the professional literature that the first bauxite mine opened 1873 in the French Provence and that the bauxite ore for the first time was scientifically described 1821 have to be revised. About this necessary revision here the essential proofs are produced.

  3. THE BAUXITES AND JELAR - BEDS

    Directory of Open Access Journals (Sweden)

    Krešimir Sakač

    1993-12-01

    Full Text Available Minor bauxite deposits and occurrences were formed in technically disturbed environments in the middle part of the Adriatic geotectonic unit in Dinarides, contemporary with the clastic Jelar-beds in the Late Lutetian time. Uneven chemical composition of these Eocene bauxites, their sporadic occurrences in developed paleorelief as well as characteristic petrographic composition of the immediate overlying rocks point out at different genetical conditions (the paper is published in Croatian.

  4. Bauxite Deposits in China

    Institute of Scientific and Technical Information of China (English)

    杨化洲

    1989-01-01

    Bauxite deposits in China,rangin in age from Late Paleozoic to Cenozoic ,are distributed mainly in Shanxi,Shandong Henan,Guizhou,Guangxi and Yunnan.Based on stratigraphic relations they can be clas-sified as 6 types:inter-system marine,inter-system continental,intra-system marine,intra-system continent-tal,weathering lateritic and weathering accumulation types.But in terms of depositional environments,only four types are distinguished,I.e.the marine deposits,continental deposits,lateritic deposits and weath-ering-accumulation deposits.These deposits have been formed in two steps:firstly,the depression of paraplatform or front basin margins in paleocontinents and secondly,the development of littoral-lagoons on the eroded surface of karstified carbonate bedrocks.The aluminum may have been derived from the carbonate rocks with which the ores are associated,or from adjacent aluminosilicate rocks.

  5. The geomicrobiology of bauxite deposits

    Directory of Open Access Journals (Sweden)

    Xiluo Hao

    2010-10-01

    Full Text Available Bauxite deposits are studied because of their economic value and because they play an important role in the study of paleoclimate and paleogeography of continents. They provide a rare record of the weathering and evolution of continental surfaces. Geomicrobiological analysis makes it possible to verify that microorganisms have played a critical role during the formation of bauxite with the possibility already intimated in previous studies. Ambient temperature, abundance of water, organic carbon and bioavailable iron and other metal substrates provide a suitable environment for microbes to inhabit. Thiobacillus, Leptospirilum, Thermophilic bacteria and Heterotrophs have been shown to be able to oxidize ferrous iron and to reduce sulfate-generating sulfuric acid, which can accelerate the weathering of aluminosilicates and precipitation of iron oxyhydroxides. Microorganisms referred to the genus Bacillus can mediate the release of alkaline metals. Although the dissimilatory iron-reducing and sulfate-reducing bacteria in bauxites have not yet been identified, some recorded authigenic carbonates and “bacteriopyrites” that appear to be unique in morphology and grain size might record microbial activity. Typical bauxite minerals such as gibbsite, kaolinite, covellite, galena, pyrite, zircon, calcium plagioclase, orthoclase, and albite have been investigated as part of an analysis of microbial mediation. The paleoecology of such bauxitic microorganisms inhabiting continental (sub surfaces, revealed through geomicrobiological analysis, will add a further dimension to paleoclimatic and paleoenvironmental studies.

  6. The geomicrobiology of bauxite deposits

    Institute of Scientific and Technical Information of China (English)

    Xiluo Hao; Kwunlun Leung; Rucheng Wang; Weidong Sun; Yiliang Li

    2010-01-01

    Bauxite deposits are studied because of their economic value and because they play an important role in the study of paleoclimate and paleogeography of continents. They provide a rare record of the weathering and evolution of continental surfaces. Geomicrobiological analysis makes it possible to verify that microorganisms have played a critical role during the formation of bauxite with the possibility already intimated in previous studies. Ambient temperature, abundance of water, organic carbon and bioavailable iron and other metal substrates provide a suitable environment for microbes to inhabit. Thiobacillus, Leptospirilum, Thermophilic bacteria and Heterotrophs have been shown to be able to oxidize ferrous iron and to reduce sulfate-generating sulfuric acid, which can accelerate the weathering of aluminosilicates and precipitation of iron oxyhydroxides. Microorganisms referred to the genus Bacillus can mediate the release of alkaline metals. Although the dissimilatory iron-reducing and sulfate-reducing bacteria in bauxites have not yet been identified, some recorded authigenic carbonates and "bacteriopyrites" that appear to be unique in morphology and grain size might record microbial activity. Typical bauxite minerals such as gibbsite, kaolinite, covellite, galena, pyrite, zircon, calcium ptagioclase, orthoclase, and albite have been investigated as part of an analysis of microbial mediation. The paleoecologyof such bauxitic microorganisms inhabiting continental (sub) surfaces, revealed through geomicrobiological analysis, will add a further dimension to paleoclimatic and paleoenvironmental studies.

  7. Calcification Transformation of Diasporic Bauxite

    Science.gov (United States)

    Zhao, Qiuyue; Zhu, Xiaofeng; Lv, Guozhi; Zhang, Zimu; Yin, Zhengnan; Zhang, Tingan

    2016-06-01

    The disposal of red mud, which is a solid waste that is generated during the extraction of alumina from bauxite, is one of major problems faced by the aluminum industry. Alkali in red mud seeping under the soil may pollute land and water. The Northeastern University, China, has proposed a calcification-carbonation method to deal with low-grade bauxite or red mud. Its main purpose is to change the equilibrium phase of red mud to 2CaO·SiO2 and CaCO3 hydrometallurgically, so that recomposed alkali-free red mud can be widely used. We conducted calcification transformation experiments using diasporic bauxite sampled from Wenshan, and investigated the effects of parameters such as diasporic bauxite grain size, temperature and treatment time on the calcification transformation digestion rate, which is also termed the calcification transformation rate (CTR). The main phase in the calcification transformation slag (CTS) is hydrogarnet with different grain sizes. The CTR increases with decrease in diasporic bauxite grain size, or increase in temperature or reaction time. The CTR reaches a maximum of 87% after 120 min reaction at 240°C. The Na2O/Al2O3 ratio decreases with increase in temperature and reaches 1.5. The sodium content in the CTS decreases with increasing reaction time and is lower than that in the red mud treated using the Bayer process (4-12%).

  8. Bauxite Based Bricks for Steel Ladle

    Institute of Scientific and Technical Information of China (English)

    Yu Lingyan; Peng Xigao

    2011-01-01

    @@ 1.Scope This standard specifies the classification,technical requirements,test methods,inspection rules,packing,marking,transportation,storage,and quality certificate of bauxite based bricks for steel ladle linings.This standard is applicable to bauxite based bricks for working layer of steel ladle.

  9. Bauxite washing for the removal of clay

    Science.gov (United States)

    Ahmad, Ishaq; Hartge, Ernst-Ulrich; Werther, Joachim; Wischnewski, Reiner

    2014-11-01

    Clay impurities associated with bauxite negatively affect the Bayer process for alumina production. These impurities should be removed as far as possible by a beneficiation technique before the ore is used as feed for the Bayer process. In this current investigation, bauxite washing was conducted in the laboratory. Bauxite washing is a physical process that causes the disintegration and deagglomeration of the clay matrix, and bauxite is liberated from the clay (mainly rich in silica). Subsequently, separation occurs with the assistance of wet screening at a predetermined cut size. Three techniques were investigated in the laboratory: drum washing, water-jet washing, and ultrasonic washing. Various operating parameters were investigated for drum washing and water-jet washing, including materials retention time, drum rotation speed, solid concentration, water-jet spray duration, pressure, and height. We concluded that the retention time of bauxite inside the drum at a solid concentration of 55wt% and a drum rotation speed of 31 r/min is the dominant parameter for the removal of clay from the bauxite surface.

  10. Bauxite washing for the removal of clay

    Institute of Scientific and Technical Information of China (English)

    Ishaq Ahmad; Ernst-Ulrich Hartge; Joachim Werther; and Reiner Wischnewski

    2014-01-01

    Clay impurities associated with bauxite negatively affect the Bayer process for alumina production. These impurities should be removed as far as possible by a beneficiation technique before the ore is used as feed for the Bayer process. In this current investigation, bauxite washing was conducted in the laboratory. Bauxite washing is a physical process that causes the disintegration and deagglomeration of the clay matrix, and bauxite is liberated from the clay (mainly rich in silica). Subsequently, separation occurs with the assistance of wet screening at a predetermined cut size. Three techniques were investigated in the laboratory: drum washing, water-jet washing, and ultrasonic washing. Various operating parameters were investigated for drum washing and water-jet washing, including materials retention time, drum rotation speed, solid concentration, water-jet spray duration, pressure, and height. We concluded that the retention time of bauxite inside the drum at a solid concentration of 55wt% and a drum rotation speed of 31 r/min is the dominant parameter for the removal of clay from the bauxite surface.

  11. Preparation of Bauxite Ceramic Microsphere

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiaosu; LIU Pingan; LI Xiuyan; SHUI Anze; ZENG Lingke

    2007-01-01

    Ceramic microspheres were prepared by using Chinese bauxite as raw materials through the centrifugal spray drying method. The control technology of microsphere size, degree of sphericity was researched. The ceramic microspheres were sintered by a double sintering process. The microstructure and composition of ceramic microsphere were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray energy spectroscopy. The results show that the degree of sphericity of the ceramic microsphere was good and the particle size was 10-100 μm. The XRD analysis reveals that the main crystalline phase of the ceramic microsphere was α- Al2O3 and mullite (3Al2O3·2SiO2). The product can be used as reinforced material for composite material, especially for antiskid and hard wearing aluminum alloy coating.

  12. Aluminum Reduction and Nitridation of Bauxite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhikuan; ZHANG Dianwei; XU Enxia; HOU Xinmei; DONG Yanling

    2007-01-01

    The application of bauxite with low Al2O3 content has been studied in this paper and β-SiAlON has been obtained from two kinds of bauxites (Al203 content 68.08 mass% and 46.30 mass% respectively) by aluminum reduction and nitridation method.The sequence of reactions has been studied using thermal analysis (TG-DTA),X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) with EDS.Compared with carbon thermal reduction and nitridation of aluminosilicates employed presently,the reaction in the system of bauxite-Al-N2 occurs at lower temperature.β-SiAlON appears as one of the main products from 1573K and exists' stably in the range of the present experimental temperature.The microstructure of β-SiAlON obtained at 1773 K is short column with 5-10μm observed by SEM.

  13. Metamorphism of bauxites on Naxos, Greece

    NARCIS (Netherlands)

    Feenstra, A.

    1985-01-01

    This thesis presents the results of a petrological-mineralogical and geochemical study of the metamorphosed karstbauxites on the island of Naxos, Greece. The bauxites have been subject to an Eocene highpressure metamorphism (M1), followed by a Late Oligocene-Miocene medium-pressure metamorphism (M2)

  14. Fight Between Bauxite Enterprises Over the Import Channels

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>China’s foreign dependence on bauxite is currently 60%,nearly the same as iron ore.China’s total imports of bauxite were 44.8449 million tons in 2011,up 49.73% year-on-year,the highest level over the same period in history. The Chinese electrolytic aluminum and aluminum oxide enterprises including Aluminum

  15. Mineralogy and geochemistry of bauxite and bentonite deposits from Mozambique

    NARCIS (Netherlands)

    Dos Muchangos, A.C.

    2000-01-01

    Results of mineralogical and geochemical studies of bauxites, kaolinitic clays and bentoniteS from Mozambique are presented in this thesis. The bauxite and kaolinitic clay deposits in Penhalonga area (in the central western part of Mozambique) are associated with Precambrian magmatic rocks and the b

  16. Spalling Resistant Bauxite Based Bricks for Cement Kiln

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiaohui; Peng Xigao

    2011-01-01

    @@ 1.Scope This standard specifies the term,definition,classification,labeling,technical requirements,test methods,inspection rules,packing,marking,transportation,storage,and quality certificate of spalling resistant bauxite based bricks for cement kiln.This standard is applicable to the spalling resistant bauxite based bricks for cement kiln.

  17. Compilation of gallium resource data for bauxite deposits

    Science.gov (United States)

    Schulte, Ruth F.; Foley, Nora K.

    2014-01-01

    Gallium (Ga) concentrations for bauxite deposits worldwide have been compiled from the literature to provide a basis for research regarding the occurrence and distribution of Ga worldwide, as well as between types of bauxite deposits. In addition, this report is an attempt to bring together reported Ga concentration data into one database to supplement ongoing U.S. Geological Survey studies of critical mineral resources. The compilation of Ga data consists of location, deposit size, bauxite type and host rock, development status, major oxide data, trace element (Ga) data and analytical method(s) used to derive the data, and tonnage values for deposits within bauxite provinces and districts worldwide. The range in Ga concentrations for bauxite deposits worldwide is

  18. Microstructure and properties of sintered mullite developed from Indian bauxite

    Indian Academy of Sciences (India)

    H S Tripathi; A Ghosh; M K Halder; B Mukherjee; H S Maiti

    2012-08-01

    Dense mullite aggregates with 72% Al2O3 have been synthesized by reaction sintering of two varieties of Indian bauxite and silica sol. The bauxites used are of inferior grade with different levels of accessory impurities such as Fe2O3, TiO2, CaO. The phase and microstructure development of sintered samples were investigated by XRD and SEM. It was found that morphology of the sintered grain is very much dependent on the impurity level. Mullite formed from bauxite-1 with low impurity is mostly equiaxed, whereas mullite developed from bauxite 2 with higher impurity particularly CaO is needle shaped. Presence of CaO in bauxite was found to be more detrimental than TiO2 and Fe2O3.

  19. Bauxite slurry pipeline: start up operation

    Energy Technology Data Exchange (ETDEWEB)

    Othon, Otilio; Babosa, Eder; Edvan, Francisco; Brittes, Geraldo; Melo, Gerson; Janir, Joao; Favacho, Orlando; Leao, Marcos; Farias, Obadias [Vale, Rio de Janeiro, RJ (Brazil); Goncalves, Nilton [Anglo Ferrous Brazil S.A., Rio de Janeiro, RJ (Brazil)

    2009-07-01

    The mine of Miltonia is located in Paragominas-PA, in the north of Brazil. Bauxite slurry pipeline starts at the Mine of Miltonia and finishes in the draining installation of Alunorte refinery at the port of Barcarena-PA, located approximately 244km away from the mine. The pipeline runs over seven cities and passes below four great rivers stream beds. The system was designed for an underground 24 inches OD steel pipe to carry 9.9 million dry metric tonnes per annum (dMTAs) of 50.5% solid concentration bauxite slurry, using only one pumping station. The system is composed by four storage tanks and six piston diaphragm pumps, supplying a flow of 1680 m3/h. There is a cathodic protection system along the pipeline extension to prevent external corrosion and five pressure monitoring stations to control hydraulic conditions, there is also a fiber optic cable interconnection between pump station and terminal station. Pipeline Systems Incorporated (PSI) was the designer and followed the commissioning program of the start up operations. This paper will describe the beginning of the pipeline operations, technical aspects of the project, the operational experiences acquired in these two years, the faced problems and also the future planning. (author)

  20. Restraining Sodium Volatilization in the Ferric Bauxite Direct Reduction System

    Directory of Open Access Journals (Sweden)

    Wentao Hu

    2016-03-01

    Full Text Available Direct reduction is an emerging utilization technology of ferric bauxite. However, it requires much more sodium carbonate than ordinary bauxite does. The volatilization is one of the most significant parts of sodium carbonate consumption, as reported in previous studies. Based on the new direct reduction method for utilization of ferric bauxite, this paper has systematically investigated factors including heating temperature, heating time, and sodium carbonate dosage influencing sodium volatilization. For the purpose of reducing sodium volatilization, the Box–Benhken design was employed, and the possibility of separating iron and sodium after direct reduction was also investigated.

  1. Rheological Behavior of the Matrixes of Bauxite-Based Castables

    Institute of Scientific and Technical Information of China (English)

    Ye Fangbao; Rigaud M.; LIU Xinhong; ZHONG Xiangchong

    2003-01-01

    Rheology of castables is greatly affected and controlled by rheological behavior of their matrix. In this work, the rheological properties of bauxite-based castable matrix have been studied. The effects of super-fine silica and alumina addition, water/cement ratio, dispersants and bauxite particle-size on viscosity, shear rate and shear stress of the slurries have been investigated. Based on these results, the range of optimum composition of the matrix with good rheological behavior has been obtained.

  2. Preparation of polymeric aluminium ferric chloride from bauxite tailings

    Directory of Open Access Journals (Sweden)

    Ma D.

    2013-01-01

    Full Text Available Bauxite tailings are the main solid wastes in the ore dressing process. The Al2O3 and Fe2O3 contents in bauxite tailings can reach 50% and 13% respectively. The present study proposed a feasible method to use bauxite tailings to prepare polymeric aluminium ferric chloride (PAFC, a new composite inorganic polymer for water purification. Bauxite tailings roasted reacting with hydrochloric acid under air, pickle liquor which mainly contains Fe3+, Al3+ was generated, then calcium aluminate was used to adjust pH value and the basicity of the pickle liquor, the PAFC was subsequently prepared after the polymerization process. The optimal synthesizing parameters for the preparation of PAFC obtained were as follows: the concentration of hydrochloric acid of 24 wt%, ratio of hydrochloric acid to bauxite tailings of 6:1, temperature of 90ºC, leaching time of 2.5 hours, ration of pickle liquor to calcium aluminate of 12:1, polymerization temperature of 90ºC and polymerization time of about 3 hours. The basicity of PAFC was higher than 68%, the sum concentration of Al2O3 and Fe2O3 was beyond 12.5%. The results of flocculation tests indicate that the PAFC has a better performance of removing the turbidity of wastewater compared to PAC, and PAFC prepared by bauxite tailings is a kind of high quality flocculants.

  3. The Hidden Troubles in The Bauxite Import Need a Timely Solution

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>As the main component in aluminum smelting, the bauxite at abroad is categorized as the gibbsite,being different from the diaspore bauxite at home.Until the end of 2005,the re- serves of the bauxite in China are ascertained to be 540 million tons,accounting for 2.3%of the globe.However,the exploitation of the bauxite in our country has reached 8%of the globe, much higher than the reserves available levels.

  4. Indonesia Tops the List of China’s Bauxite Import Sources

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>The Industry Injury Investigation Bureau of the Ministry of Commerce has issued an early warning that China’s dependence on foreign bauxite is as high as 60%, of which bauxite from Indonesia accounts for more than 70% of the total import. Bauxite imported from Indonesia has, to a certain extent, dominated the development of China’s aluminum industry.The bauxite reserve is tremendous in the world while that remains on the brink of exhaustion in China. As China expands its production scale of bauxite, its import also rises continuously.

  5. Bauxite and bauxite residue, characterization and electron microscopy study; Bauxita e seu residuo, caracterizacao e estudo por microscopia eletronica

    Energy Technology Data Exchange (ETDEWEB)

    Antunes, M.L.P.; Conceicao, F.T., E-mail: malu@sorocaba.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil); Toledo, S.P.; Kiyohara, P.K. [Universidade de Sao Paulo (IF/LME/USP), SP (Brazil)

    2012-07-01

    Through the Bayer process, bauxite is refined and alumina is produced. In this process, a highly alkaline residue, red mud is generated and its disposal represents an environmental problem. The aim of this paper is to present the characterization of Brazilian bauxite and Brazilian red mud by: X-ray diffraction, specific surface area, chemical composition analysis by ICP-MS, transmission electron microscopy (TEM) and energy dispersive X-ray spectrometry (EDS), and scanning electron microscopy (SEM) and discuss possible applications of this residue. The results identify as a constituent of both materials: Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, TiO{sub 2} and SiO{sub 2} and the presence of Na{sub 2}O in residue. The analysis by electron microscopy of Bauxite shows particles with hexagonal shape and red mud shows small particles size. (author)

  6. Industrial Preparation of Bauxite-based Mullite Raw Material

    Institute of Scientific and Technical Information of China (English)

    YANG Zhongzheng; DING Baohua

    2008-01-01

    Bauxite-based mullite grogs were prepared with grade II bauxite(≤3mm)and coal gangue(≤3mm)as starting materials with formula of w(Al2O3)=68%~72%.Mill the mixture to particle size≤0.044mm by wet milling to homogenize chemical composition. After shaping by wet extrusion and drying, the materials were fired at 1550℃, 1600℃ and 1700℃ for 6 hours respectively. After cooling apparent porosity and bulk density of fired materials were tested. The results show as follows: the appropriate sintering temperature for bauxite-based mullite with homogeneous and consistent composition and microstructure and properties is 1600℃,at which the mullite has apparent porosity≤1.5%,bulk density≥2.81g·cm-3and refractoriness under load is 1610-1650℃.Compared with the laboratory results, the sintering temperature is lowered about 100℃,bulk density increased 0.06g?cm-3.The industrial feasibility of preparing bauxite-based mullite grogs with the processing is confirmed.

  7. Adsorption behavior of Pb2+ and Cd2+ ions on bauxite flotation tailings

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-hua; LAN Ye; HUANG Chuan-bing

    2008-01-01

    The adsorption behavior of Pb2+ and Cd2+ ions on bauxite flotation railings was investigated to demonstrate the adsorptivity of the bauxite flotation tailings. The adsorption percentage of Pb2+ and Cd2+ ions as a function of adsorbent dosage, solution pH value and shaking time were determined by batch experiments. The maximum adsorption percentage of 99.93% for Pb2+ ions and 99.75% for Cd2+ ions were obtained by using bauxite flotation railings as adsorbent. The methods, such as zeta potentials, specific surface area measurements and the analysis of adsorption kinetics, were introduced to analyze the adsorption mechanisms of the Pb2+ ions on bauxite flotation tailings. The isoelectric point of bauxite flotation railings shifts from 3.6 to 5.6 in the presence of Pb2+ ions. The specific surface area of bauxite flotation tailings changes from 12.57 to 20.63 m2/g after the adsorption of Pb2+ ions. These results indicate that a specific adsorption of the cation species happens on the surface of bauxite flotation tailings. Adsorption data of Pb2+ ions on the surface of bauxite flotation tailings can be well described by Langmuir model, and the pseudo-second-order kinetic model provides the best correlation for the adsorption data of Pb2+ and Cd2+ ions on bauxite flotation railings.

  8. Bauxite Based Refractory Bricks for Hot Blast Stove YB/T 5016-2000

    Institute of Scientific and Technical Information of China (English)

    Wang Jing; Chai Junlan

    2008-01-01

    @@ 1Scope This standard specifies the technical requirements, test method, inspection rules, packing, marking, transportation, storage and quality certificate of bauxite based refractory bricks for hot blast stove.

  9. Bauxites and associated terrestrial sediments in Nigeria and their position in the Bauxite belts of Africa

    Science.gov (United States)

    Valeton, I.

    The African surface, Lower Tertiary in age, its special ferralitic weathering mantle and reworking products (LDF) are discussed. Dominant facts are: 1. Not only bauxitisation but also supergene ore formation of manganese, iron, nickel, gold, gossan mineralisation and supergene phosphatisation characterize that Lower Tertiary ≪surface≫. 2. From the paleocoast to the inland, high-grade bauxites change laterally into low-grade ferralites or ferricretes. 3. The African planation surface on high plateaus in Nigeria represent the beginning of a morphogenetic sequence. It is expressed by an interaction of in-situ weathering, induration to ferricretes, alucretes, silcretes and their reworking and resedimentation as laterite-derived facies (LDF) on a topographically and morphologically low relief in a short time span during Paleogene. One to several sequences of ≪composed profiles≫ or only one ≪ in-situ paleosol covered by LDF≫ act as forming factors of that ≪first-order≫ paleosurface. 4. Contemporaneous or later block tectonics led to a displacement and tilting of surfaces and activation of erosion, progressively creating a relictic inselberg landscape. 5. Refilling of older erosion channels and depressions by younger volcanic flows and sediments gives the image of a uniform land surface which - in reality - is composed of surfaces and connected weathering profiles of different age forming a ≪Schachtelrelief≫. 6. Younger polyphase soil alteration results in polygenetic soils. 7. New supergene geochemical provinces develop in the ferralitic weathering crust with increasing tendence to mono-element concentration.

  10. Leaching kinetics of gibbsitic bauxite with sodium hydroxide

    Directory of Open Access Journals (Sweden)

    Abdel-Aal El-Sayed A.

    2016-01-01

    Full Text Available In this paper the results of a leaching kinetics study of bauxite ore with sodium hydroxide are presented. The effect of ore particle size, sodium hydroxide concentration and reaction temperature on the Al2O3 extraction rate was determined. The results obtained showed that 99% of Al2O3 was leached out using −200+270 mesh ore particle size at a reaction temperature of 105 °C for 60 min reaction time with 250 g/L NaOH. The solid-to-liquid ratio was maintained constant at 1:20. The results indicated that leaching of bauxite is the rate controlling process. The activation energy was determined to be 46.04 kJ/mole, which was characteristic for a chemically controlled process.

  11. THE SOLUBILITY OF MILAS BAUXITE ORE IN SULPHURIC ACI

    Directory of Open Access Journals (Sweden)

    Mustafa GULFEN

    2001-06-01

    Full Text Available The effects of calcination conditions,sulphuric acid concentrations and dissolvingtemperature and period as parameters to thesolubility of the bauxite ore from Gobekdagı reservesin Mugla-Milas region were investigated. The bauxitesamples were calcined in different periods at differenttemperatures. Then the solubility of the calcinedbauxite samples in sulphuric acid solution wasexamined. Dissolving activation energy (Ea wascalculated using the optimum kinetics equation andthe results obtained from the solubility studiesexamined dissolving temperatures and periods

  12. Potential Health Impacts of Bauxite Mining in Kuantan

    OpenAIRE

    Abdullah, Noor Hisham; Mohamed, Norlen; Sulaiman, Lokman Hakim; Zakaria, Thahirahtul Asma; Rahim, Daud Abdul

    2016-01-01

    Bauxite mining is not known to most Malaysian except recently due to environmental pollution issues in Kuantan, Pahang. Potential impacts are expected to go beyond physical environment and physical illness if the situation is not controlled. Loss of economic potentials, and the presence of unpleasant red dust causing mental distress, anger and community outrage. More studies are needed to associate it with chronic physical illness. While evidences are vital for action, merely waiting for a di...

  13. The Characterization of a Bauxite Waste From The Bayer Process

    Directory of Open Access Journals (Sweden)

    Nevin Yalçın

    2001-06-01

    Full Text Available The Bayer process for the alumina frombauxite produce a high quantity of waste in the formof mud. This waste -red mud- ııresent seriousproblems on environmental pollution. A possiblesolution for these wastes would be the utilization atthe ceramic industry. Because of this, thecharacterization of a bauxite 'vaste has beenperformed using various techniques. The particle sizedistribution licd bet1veen 1 and 30 J.lm. The meandeıısit

  14. China’s Total Bauxite Resource Volume has Topped 4 Billion Tonnes

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>According to data published in the "Communiqué on Land and Resources of China for 2012" by The Ministry of Land and Resources, in the whole year of 2012, the volume of newly added identified bauxite resource amounted to 210 million tonnes, at the end of 2012 the total volume of domestic identified bauxite resource

  15. Binding of Vapour-Phase Mercury (Hg0) on Chemically Treated Bauxite Residues (Red Mud)

    Science.gov (United States)

    In this study, Hg capture using red mud, seawater-neutralized red mud, and acid-treated red mud is evaluated and compared to other, more conventional sorbent materials. Red mud (also known as bauxite residue) is a by-product of extracting alumina from ground bauxite ore by treati...

  16. UNDERGROUND BAUXITE EXPLOITATION IN THE WESTERN DINARIDS ESSENTIAL FACTS AND COMMENTS

    Directory of Open Access Journals (Sweden)

    Slavko Vujec

    1994-12-01

    Full Text Available After a short information about the causes both for the deficiency of papers on bauxite underground mines and for the development of such mines, a concise sketch of the geologic structures of the bauxite regions in the Western Dinarids, inclusive the chemical composition of the bauxites, is given. The main portion of the paper is devoted to the description of the following bauxitic regions: Drniš (with the mines Kalun and Kumanovo, Obrovac (Dračevac, Ćukovac—Grižinice and Krš, Mostar (Orašnica, Tribošić, Trobukva, Dabrica, Jajce (Poljane, Crvene Stijene, Bosanska Krupa (Risovac, and Sinj (Visoka. Presented are the »bauxitic« history of the region as well as its mining characteristics, from the mode of opening to the used mining methods, with their adventages and disadvantages. Comments are made, but no conclusions drawn; the future remains open.

  17. Effect of bauxite addition on densification and mullitization behaviour of West Bengal clay

    Indian Academy of Sciences (India)

    N S Raut; P Biswas; T K Bhattacharya; K Das

    2008-12-01

    The effect of bauxite addition on the densification and mullitization of reaction sintered bauxite–clay mixture had been studied in the temperature range 1400–1500°C. The maximum bulk density (2.89 g/cc) and minimum apparent porosity (0.58%) was achieved by addition of 50 wt% bauxite. The impurities present in bauxite and clay formed liquid phase which helped in particle diffusion to aid densification. The X-ray diffraction of sample fired at 1500°C showed cristoballite phase gradually disappearing and at the same time mullite and -Al2O3 phase appearing at a higher level of bauxite addition. The in situ nascent alumina formed was reactive that facilitated the formation of secondary mullite by solution precipitation mechanism. The presence of bauxite also changed the morphology of the mullite particles. Two types of mullite were distinctly observed in the SEM photographs: elongated primary mullite and equiaxed secondary mullite.

  18. Study on the sedimentation capability of bauxite flotation concentrate

    Institute of Scientific and Technical Information of China (English)

    Chen Jianming; Liu Sanjun; Qin Wenqing; Chen Zhiyou; Hu Yuehua

    2008-01-01

    The sedimentation behaviors of bauxite flotation concentrates were investigated at different pH values and floc-eulant dosages.The effects of three types of flocculants( cationic,anionic and non-ionic polyacrylamide flocculants)as well as the moleculax weight of anionic flocculants on the sedimentation of concentrate were studied.It is shown from the experimental results that at the pH 7.0,best sedimentation capability is reached when anionic polyacrylamide flocculant (molecular weight 14 miLlion)is added and the optimal dosage is 30 g/t.

  19. Mineralogy, Geochemistry and Stable Isotope Studies of the Dopolan Bauxite Deposit, Zagros Mountain, Iran

    Directory of Open Access Journals (Sweden)

    Somayeh Salamab Ellahi

    2016-02-01

    Full Text Available The Dopolan deposit is a Mediterranean-type bauxite located in the Zagros Fold-Thrust Zone, Iran. This deposit consists of five lithological members including iron-rich, clay-rich, oolitic, pisolitic and organic matter-containing bauxites. The mineralogy of the deposit includes diaspore, boehmite, and kaolinite, nacrite, with minor pyrite, anatase and rutile. Geochemical studies show that light rare earth elements (LREEs are enriched relative to heavy rare earth elements (HREEs in all members, supporting an authigenic origin. Mass changes based on Ti as an immobile element indicate that conventionally-immobile elements (Al, Nb, Ta, Zr, Hf are enriched in situ in the residual units, whereas mobile elements (K, Ca, Si were depleted during bauxitization. This study shows that the Khaneh–Kat argillitic dolomite is the likely parent rock. The δ18O (7.63‰to 9.35‰ and D values (49.91‰to 66.49‰ for kaolinite in the bauxite samples suggest equilibration with meteoric waters which supports a supergene origin. Bauxitization occurred in a warm climate with relatively constant isotopic composition suggesting climate stability during the development of bauxite horizons and remobilization of Al (with formation of secondary boehmite. The δ13C values of calcite (7.3‰ in the bauxite support the idea that the Khaneh–Kat Formation has experienced post-depositional isotope exchange with meteoric waters during the karstification process.

  20. Extraction of Alumina from high-silica bauxite by hydrochloric acid leaching using preliminary roasting method

    Science.gov (United States)

    Valeev, D. V.; Mansurova, E. R.; Bychinskii, V. A.; Chudnenko, K. V.

    2016-02-01

    A process of dissolution Severoonezhsk deposit boehmite-kaolinite bauxite by hydrochloric acid, as well as the processes that occur during open-air calcination, were investigated. A dehydration process has been studied, and the basic phase transformation temperatures were identified. Temperature and time of calcination influence on bauxite dehydration speed were determined. It is shown that the preliminary calcination increases the extraction ratio of alumina into solution up to 89%. Thermodynamic modelling of physical and chemical processes of bauxite decomposition by hydrochloric acid and the basic forms of aluminium speciation in solution were obtained.

  1. West Inner Mongolia Coalfield to be the Largest Bauxite Mine in China

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>With the acceleration of industrialization of extraction of alumina from high aluminum fly ash technology, the West Inner Mongolia coalfield is expected to become the largest bauxite mine with the largest aluminum reserves in China.

  2. Flotation de-silicating from diasporic-bauxite with cetyl trimethylammonium bromide

    Institute of Scientific and Technical Information of China (English)

    王毓华; 胡岳华; 刘晓文

    2003-01-01

    Using cetyl trimethylammonium bromide (CTAB) as collector, the flotation de-silicating from diasporicbauxite was investigated. And the Zeta potentials and contact-angles of silicate minerals and diaspore were also stuite and illite become more positive, and the contact angles of these three silicates also increase evidently in the pH range of 2-8, but the Zeta potentials and contact angles of diaspore change little. So, the floatability of the four minerals is in the following order: pyrophyllite>kaolinite≈illite>diaspore. The open-circuit flotation results also show that a bauxite concentrate with m(Al2 O3 )/m(SiO2 ) over 9.3 and Al2 O3 recovery over 76% can be obtained from diasporic-bauxite ore. The result of XRD of the bauxite concentrate shows that pyrophyllite is easier to be removed from diasporic-bauxite than illite and kaolinite due to its better floatability.

  3. Comparative Analysis of Processes for Recovery of Rare Earths from Bauxite Residue

    Science.gov (United States)

    Borra, Chenna Rao; Blanpain, Bart; Pontikes, Yiannis; Binnemans, Koen; Van Gerven, Tom

    2016-11-01

    Environmental concerns and lack of space suggest that the management of bauxite residue needs to be re-adressed. The utilization of the residue has thus become a topic high on the agenda for both academia and industry, yet, up to date, it is only rarely used. Nonetheless, recovery of rare earth elements (REEs) with or without other metals from bauxite residue, and utilization of the left-over residue in other applications like building materials may be a viable alternative to storage. Hence, different processes developed by the authors for recovery of REEs and other metals from bauxite residue were compared. In this study, preliminary energy and cost analyses were carried out to assess the feasibility of the processes. These analyses show that the combination of alkali roasting-smelting-quenching-leaching is a promising process for the treatment of bauxite residue and that it is justified to study this process at a pilot scale.

  4. Comparative Analysis of Processes for Recovery of Rare Earths from Bauxite Residue

    Science.gov (United States)

    Borra, Chenna Rao; Blanpain, Bart; Pontikes, Yiannis; Binnemans, Koen; Van Gerven, Tom

    2016-09-01

    Environmental concerns and lack of space suggest that the management of bauxite residue needs to be re-adressed. The utilization of the residue has thus become a topic high on the agenda for both academia and industry, yet, up to date, it is only rarely used. Nonetheless, recovery of rare earth elements (REEs) with or without other metals from bauxite residue, and utilization of the left-over residue in other applications like building materials may be a viable alternative to storage. Hence, different processes developed by the authors for recovery of REEs and other metals from bauxite residue were compared. In this study, preliminary energy and cost analyses were carried out to assess the feasibility of the processes. These analyses show that the combination of alkali roasting-smelting-quenching-leaching is a promising process for the treatment of bauxite residue and that it is justified to study this process at a pilot scale.

  5. Preparation and Microstructure of Bauxite-Based Sialon by Reduction Nitridation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Haijun; LIU Zhanjie; ZHONG Xiangchong

    2004-01-01

    The phase compostition and microstructure of Sialon prepared from Chinese bauxite have been studied.The use of Si powder is more effective than that of activated carbon for reduction-nitridation.For bauxite specimens with 40~50% Si addition,more than 90% of Sialon may be obtained when nitrided at 1450~1500℃;the main crystalline phase is O'-Sialon(Z=0.2).

  6. THE DIGESTION OPERATION IN THE ALKALI ALUMINAT SOLUTIONS OF ALUMINUM HYDROXIDES IN THE BOEHMITIC BAUXITES

    Directory of Open Access Journals (Sweden)

    Sami ŞAHİN

    1999-01-01

    Full Text Available At present more than 90 per cent of the world's alumina is produced by the Bayer process, a simple technology providing high purity final product. A part from some exceptional local conditions, bauxite is processed almost solely by this technology. As a benefication process, alumina production releases the aluminum oxide content of bauxite from other accompanying oxides thus providing alumina suitable for electrolysis in a cryolite melt. The basic theory of the Bayer process was elaborated by K.J. Bayer and described in his patents in 1887 and 1892. The first patent refers to the aid of seed crystals of aluminum hydroxide or of carbonic acid, that is, to the precipitation and carbonation processes. The second patent formulates the concept that the aluminum oxide content of bauxites can be dissolved in sodium hydroxide solutions, with the formulation of sodium aluminate, a process called digestion nowadays. The most important operations of the Bayer technology are bauxite preparation, crushing, grinding, digestion, red mud separation, thickening, washing, filtration, precipitation, calcination and evaporation. In spite of its great significance as regards the complete Bayer technology, the structure of sodium aluminate solutions has not been cleared up definitely yet. Boehmite is the most important aluminum mineral of karstic bauxites. Some experimental results showing the various effects on aluminum hydroxides by alkali process from boehmitic bauxites and the factors gowerning the digestion operation of aluminate solutions were investigated.

  7. Potential Health Impacts of Bauxite Mining in Kuantan.

    Science.gov (United States)

    Abdullah, Noor Hisham; Mohamed, Norlen; Sulaiman, Lokman Hakim; Zakaria, Thahirahtul Asma; Rahim, Daud Abdul

    2016-05-01

    Bauxite mining is not known to most Malaysian except recently due to environmental pollution issues in Kuantan, Pahang. Potential impacts are expected to go beyond physical environment and physical illness if the situation is not controlled. Loss of economic potentials, and the presence of unpleasant red dust causing mental distress, anger and community outrage. More studies are needed to associate it with chronic physical illness. While evidences are vital for action, merely waiting for a disease to occur is a sign of failure in prevention. All responsible agencies should focus on a wider aspect of health determinants rather than merely on the occurrence of diseases to act and the need to emphasize on sustainable mining to ensure health of people is not compromised.

  8. Beneficiation of low-grade diasporic bauxite with hydrocyclone

    Institute of Scientific and Technical Information of China (English)

    GAO Shu-ling; LI Xia-an; WEI De-zhou; FANG Ping; JIA Chun-yun; LIU Wen-gang; HAN Cong

    2008-01-01

    Low-grade diasporic bauxite was treated with hydrocyclone of small cone-angle. The effects of apex diameter, feed pressure and feed concentration on separation indexes were tested, and then the separation process was discussed by hydrokinetics tentatively. The results show that the increase of apex diameter changes the spacial locality of the envelope of zero vertical velocity, resulting in decrease of the ratio of Al2O3/SiO2 in overflow and increase of the recovery of Al2O3 in underflow, while feed pressure and feed concentration have no remarkable effect on the spacial locality of the envelope of zero vertical velocity, however, the separation indexes are improved by the increase of feed pressure, but are worsened by the increase of feed concentration.

  9. Modeling interactions of Hg(II) and bauxitic soils.

    Science.gov (United States)

    Weerasooriya, Rohan; Tobschall, Heinz J; Bandara, Atula

    2007-11-01

    The adsorptive interactions of Hg(II) with gibbsite-rich soils (hereafter SOIL-g) were modeled by 1-pK surface complexation theory using charge distribution multi-site ion competition model (CD MUSIC) incorporating basic Stern layer model (BSM) to account for electrostatic effects. The model calibrations were performed for the experimental data of synthetic gibbsite-Hg(II) adsorption. When [NaNO(3)] > or = 0.01M, the Hg(II) adsorption density values, of gibbsite, Gamma(Hg(II)), showed a negligible variation with ionic strength. However, Gamma(Hg(II)) values show a marked variation with the [Cl(-)]. When [Cl(-)] > or = 0.01M, the Gamma(Hg(II)) values showed a significant reduction with the pH. The Hg(II) adsorption behavior in NaNO(3) was modeled assuming homogeneous solid surface. The introduction of high affinity sites, i.e., >Al(s)OH at a low concentration (typically about 0.045 sites nm(-2)) is required to model Hg(II) adsorption in NaCl. According to IR spectroscopic data, the bauxitic soil (SOIL-g) is characterized by gibbsite and bayerite. These mineral phases were not treated discretely in modeling of Hg(II) and soil interactions. The CD MUSIC/BSM model combination can be used to model Hg(II) adsorption on bauxitic soil. The role of organic matter seems to play a role on Hg(II) binding when pH>8. The Hg(II) adsorption in the presence of excess Cl(-) ions required the selection of high affinity sites in modeling.

  10. Predictive hydrogeochemical modelling of bauxite residue sand in field conditions.

    Science.gov (United States)

    Wissmeier, Laurin; Barry, David A; Phillips, Ian R

    2011-07-15

    The suitability of residue sand (the coarse fraction remaining from Bayer's process of bauxite refining) for constructing the surface cover of closed bauxite residue storage areas was investigated. Specifically, its properties as a medium for plant growth are of interest to ensure residue sand can support a sustainable ecosystem following site closure. The geochemical evolution of the residue sand under field conditions, its plant nutrient status and soil moisture retention were studied by integrated modelling of geochemical and hydrological processes. For the parameterization of mineral reactions, amounts and reaction kinetics of the mineral phases natron, calcite, tricalcium aluminate, sodalite, muscovite and analcime were derived from measured acid neutralization curves. The effective exchange capacity for ion adsorption was measured using three independent exchange methods. The geochemical model, which accounts for mineral reactions, cation exchange and activity corrected solution speciation, was formulated in the geochemical modelling framework PHREEQC, and partially validated in a saturated-flow column experiment. For the integration of variably saturated flow with multi-component solute transport in heterogeneous 2D domains, a coupling of PHREEQC with the multi-purpose finite-element solver COMSOL was established. The integrated hydrogeochemical model was applied to predict water availability and quality in a vertical flow lysimeter and a cover design for a storage facility using measured time series of rainfall and evaporation from southwest Western Australia. In both scenarios the sand was fertigated and gypsum-amended. Results show poor long-term retention of fertilizer ions and buffering of the pH around 10 for more than 5 y of leaching. It was concluded that fertigation, gypsum amendment and rainfall leaching alone were insufficient to render the geochemical conditions of residue sand suitable for optimal plant growth within the given timeframe. The

  11. Proposal for management and alkalinity transformation of bauxite residue in China.

    Science.gov (United States)

    Xue, Shengguo; Kong, Xiangfeng; Zhu, Feng; Hartley, William; Li, Xiaofei; Li, Yiwei

    2016-07-01

    Bauxite residue is a hazardous solid waste produced during the production of alumina. Its high alkalinity is a potential threat to the environment which may disrupt the surrounding ecological balance of its disposal areas. China is one of the major global producers of alumina and bauxite residue, but differences in alkalinity and associated chemistry exist between residues from China and those from other countries. A detailed understanding of the chemistry of bauxite residue remains the key to improving its management, both in terms of minimizing environmental impacts and reducing its alkaline properties. The nature of bauxite residue and the chemistry required for its transformation are still poorly understood. This review focuses on various transformation processes generated from the Bayer process, sintering process, and combined Bayer-sintering process in China. Problems associated with transformation mechanisms, technical methods, and relative merits of these technologies are reviewed, while current knowledge gaps and research priorities are recommended. Future research should focus on transformation chemistry and its associated mechanisms and for the development of a clear and economic process to reduce alkalinity and soda in bauxite residue.

  12. Reforestation of bauxite mine spoils with Eucalyptus tereticornis Sm. seedlings inoculated with arbuscular mycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    N. Krishnakumar

    2012-11-01

    Full Text Available Open cast mining for bauxite at Yercaud hills (India resulted indegradation of forest ecosystem and production of large quantities of waste rocks (called mine spoils. To ameliorate mine spoils, topsoil is used to spread over before the planting of tree species, conventional method as the topsoil has a good structure, water holding capacity and beneficial microbes like Arbuscular Mycorrhizal (AM fungi essential for plant growth.However, the use of top soil is expensive and in this study bauxite mine spoils were reforestated with AM fungi instead of it. The beneficial microbes AM fungi (Glomus aggregatum Schenck & Smith, G. fasciculatum(Thatcher Gerd. & Trappe emend. Walker & Koske, G. geosporum(Nicol. & Gerd. Walker were isolated, cultured and inoculated into the seedlings of Eucalyptus tereticornis Sm. and grown in bauxite mine spoils as potting medium under nursery conditions. Then, the biomass improved seedlings of E. tereticornis with inoculation of AM fungi were directly transplanted at bauxite mine spoils. After transplantation of the seedlings at bauxite mine spoils, the growth and survival rate were monitored for two years. The AM fungi inoculated seedlings of E. tereticornis showed 95% survival over the control seedlings and their growth was also significantlyhigher. Tissue nutrients (N, P, K were also found higher inAM fungi inoculated E. tereticornis than un inoculated control seedlings.

  13. Feasible conversion of solid waste bauxite tailings into highly crystalline 4A zeolite with valuable application.

    Science.gov (United States)

    Ma, Dongyang; Wang, Zhendong; Guo, Min; Zhang, Mei; Liu, Jingbo

    2014-11-01

    Bauxite tailings are a major type of solid wastes generated in the flotation process. The waste by-products caused significant environmental impact. To lessen this hazardous effect from poisonous mine tailings, a feasible and cost-effective solution was conceived and implemented. Our approach focused on reutilization of the bauxite tailings by converting it to 4A zeolite for reuse in diverse applications. Three steps were involved in the bauxite conversion: wet-chemistry, alkali fusion, and crystallization to remove impurities and to prepare porous 4A zeolite. It was found that the cubic 4A zeolite was single phase, in high purity, with high crystallinity and well-defined structure. Importantly, the 4A zeolite displayed maximum calcium ion exchange capacity averaged at 296 mg CaCO3/g, comparable to commercially-available zeolite (310 mg CaCO3/g) exchange capacity. Base on the optimal synthesis condition, the reaction yield of zeolite 4A from bauxite tailings achieved to about 38.43%, hence, this study will provide a new paradigm for remediation of bauxite tailings, further mitigating the environmental and health care concerns, particularly in the mainland of PR China.

  14. Deep-sea foraminifera from the Cassidaigne Canyon (NW Mediterranean): Assessing the environmental impact of bauxite red mud disposal

    NARCIS (Netherlands)

    Fontanier, C.; Fabri, M.-C.; Buscail, R.; Biscara, L.; Koho, K.A.; Reichart, G.-J.; Cossa, D.; Galaup, S.; Chabaud, G.; Pigot, L.

    2012-01-01

    Benthic foraminiferal assemblages were investigated from two sites along the axis of the Cassidaigne Canyon (NW Mediterranean Sea). Both areas are contaminated by bauxite red mud enriched in iron, titanium, vanadium and chromium. These elemental enrichments are related to bauxite-derived minerals an

  15. Hidden values in bauxite residue (red mud): recovery of metals.

    Science.gov (United States)

    Liu, Yanju; Naidu, Ravi

    2014-12-01

    Bauxite residue (red mud) is a hazardous waste generated from alumina refining industries. Unless managed properly, red mud poses significant risks to the local environment due to its extreme alkalinity and its potential impacts on surface and ground water quality. The ever-increasing generation of red mud poses significant challenges to the aluminium industries from management perspectives given the low proportion that are currently being utilized beneficially. Red mud, in most cases, contains elevated concentrations of iron in addition to aluminium, titanium, sodium and valuable rare earth elements. Given the scarcity of iron supply globally, the iron content of red mud has attracted increasing research interest. This paper presents a critical overview of the current techniques employed for iron recovery from red mud. Information on the recovery of other valuable metals is also reviewed to provide an insight into the full potential usage of red mud as an economic resource rather than a waste. Traditional hydrometallurgy and pyrometallurgy are being investigated continuously. However, in this review several new techniques are introduced that consider the process of iron recovery from red mud. An integrated process which can achieve multiple additional values from red mud is much preferred over the single process methods. The information provided here should help to improve the future management and utilization of red mud.

  16. Rhizobial characterization in revegetated areas after bauxite mining.

    Science.gov (United States)

    Borges, Wardsson Lustrino; Prin, Yves; Ducousso, Marc; Le Roux, Christine; de Faria, Sergio Miana

    2016-01-01

    Little is known regarding how the increased diversity of nitrogen-fixing bacteria contributes to the productivity and diversity of plants in complex communities. However, some authors have shown that the presence of a diverse group of nodulating bacteria is required for different plant species to coexist. A better understanding of the plant symbiotic organism diversity role in natural ecosystems can be extremely useful to define recovery strategies of environments that were degraded by human activities. This study used ARDRA, BOX-PCR fingerprinting and sequencing of the 16S rDNA gene to assess the diversity of root nodule nitrogen-fixing bacteria in former bauxite mining areas that were replanted in 1981, 1985, 1993, 1998, 2004 and 2006 and in a native forest. Among the 12 isolates for which the 16S rDNA gene was partially sequenced, eight, three and one isolate(s) presented similarity with sequences of the genera Bradyrhizobium, Rhizobium and Mesorhizobium, respectively. The richness, Shannon and evenness indices were the highest in the area that was replanted the earliest (1981) and the lowest in the area that was replanted most recently (2006).

  17. Pre-desilication and digestion of gibbsitic bauxite with lime in sodium aluminate liquor

    Science.gov (United States)

    Pan, Xiao-lin; Yu, Hai-yan; Dong, Kai-wei; Tu, Gan-feng; Bi, Shi-wen

    2012-11-01

    The effect of lime on the pre-desilication and digestion of gibbsitic bauxite in synthetic sodium aluminate liquor at different temperatures was investigated. The bauxite is comprised of gibbsite, aluminogoethite, hematite, kaolin, quartz, and minor boehmite. Lime increases the desilication efficiency of the bauxite during the pre-desilication process by promoting the conversion of sodalite and cancrinite to hydrogarnet. Desilication reactions during the digestion process promoted by lime result in the loss of Al2O3 entering the red mud, but the amount of aluminogoethite-to-hematite conversion promoted by lime leads to the increase of aluminogoethitic Al2O3 entering the digested liquor. The alumina digestion rate at 245°C is higher than that at 145°C due to the more pronounced conversion of aluminogoethite to hematite. The soda consumption during the digestion process decreases due to lime addition, especially at higher temperatures.

  18. A review of the characterization and revegetation of bauxite residues (Red mud).

    Science.gov (United States)

    Xue, Shengguo; Zhu, Feng; Kong, Xiangfeng; Wu, Chuan; Huang, Ling; Huang, Nan; Hartley, William

    2016-01-01

    Bauxite residue (Red mud) is produced in alumina plants by the Bayer process in which Al-containing minerals are dissolved in hot NaOH. The global residue inventory reached an estimated 3.5 billion tons in 2014, increasing by approximately 120 million tons per annum. The appropriate management of bauxite residue is becoming a global environmental concern following increased awareness of the need for environmental protection. Establishment of a vegetation cover is the most promising way forward for the management of bauxite residue, although its physical and chemical properties can limit plant growth due to high alkalinity and salinity, low hydraulic conductivity, trace element toxicity (Al and Fe), and deficiencies in organic matter and nutrition concentrations. This paper discusses the various revegetation and rehabilitation strategies. Studies of the rehabilitation of bauxite residues have mainly focused on two approaches, amelioration of the surface layer and screening of tolerant plants and soil microorganisms. Amendment with gypsum can reduce the high alkalinity and salinity, promote soil aggregation, and increase the hydraulic conductivity of bauxite residues. Organic matter can provide a source of plant nutrients, form stable complexes with metal cations, promote hydraulic conductivity, stabilize soil structure, and provide an energy source for soil organisms. Tolerant plants and microorganisms such as halophytes and alkaliphilic microbes show the greatest potential to ameliorate bauxite residues. However, during restoration or as a result of natural vegetation establishment, soil formation becomes a critical issue and an improved understanding of the various pedogenic processes are required, and future direction should focus on this area.

  19. Improvement of Sodium Leaching Ratio of Ferric Bauxite Sinter after Direct Reduction

    Directory of Open Access Journals (Sweden)

    Wentao Hu

    2017-01-01

    Full Text Available The sodium leaching ratio (ηN of ferric bauxite direct reduction process is much lower than that of ordinary bauxite; thus, the former consumes more sodium than the latter. ηN can be promoted by increasing the dosage of sodium or restricted by increasing the heating temperature and time. However, the restriction effect of heating temperature is 16.67 times larger than that of heating time, and the restriction effect decreases 47.03 times faster when heating temperature increases than that process of heating time. These imply that ηN improves with the increasing sodium carbonate dosage and the decreasing heating temperature.

  20. The Effect of Bauxite Substitution on High Temperature Strength Properties of Zirconia—corundum Mullite Material

    Institute of Scientific and Technical Information of China (English)

    ZHONGWei-bin; SUNGeng-chen; 等

    1994-01-01

    Investigations on the effect of bauxite substi-tution for industrial alumina on high temperature strength and thermal shock resistance of reaction-sintered zirconia-corundum-mullite material(ZrO2 15%) have indicated that bauxite substitution would lead to increase in modulus of rupture at 1000-1400℃ as well as improvement in thermal shock resistance,Hot strength value reaches a maximum at 15% buxite addition.The mecha-nism of mechanical behavior at elevated tempera-tures is discussed in association with changes in mi-crostructural characteristics.

  1. Soil physical properties of high mountain fields under bauxite mining

    Directory of Open Access Journals (Sweden)

    Dalmo Arantes de Barros

    2013-10-01

    Full Text Available Mining contributes to the life quality of contemporary society, but can generate significant impacts, these being mitigated due to environmental controls adopted. This study aimed to characterize soil physical properties in high-altitude areas affected by bauxite mining, and to edaphic factors responses to restoration techniques used to recover mined areas in Poços de Caldas plateau, MG, Brazil. The experiment used 3 randomized block design involving within 2 treatments (before mining intervention and after environmental recovery, and 4 replicates (N=24. In each treatment, soil samples with deformed structures were determined: granulometry, water-dispersible clay content, flocculation index, particle density, stoniness level, water aggregate stability, and organic matter contend. Soil samples with preserved structures were used to determine soil density and the total volume of pores, macropores, and micropores. Homogenization of stoniness between soil layers as a result of soil mobilization was observed after the mined area recovery. Stoniness decreased in 0.10-0.20 m layer after recovery, but was similar in the 0-0.10 m layer in before and after samples. The recovery techniques restored organic matter levels to pre-mining levels. However, changes in soil, including an increase in soil flocculation degree and a decrease in water-dispersible clays, were still apparent post-recovery. Furthermore, mining operations caused structural changes to the superficial layer of soil, as demonstrated by an increase in soil density and a decrease in total porosity and macroporosity. Decreases in the water stability of aggregates were observed after mining operations.

  2. Novel predictors of soil genesis following natural weathering processes of bauxite residues.

    Science.gov (United States)

    Zhu, Feng; Xue, Shengguo; Hartley, William; Huang, Ling; Wu, Chuan; Li, Xiaofei

    2016-02-01

    Bauxite residue often has chemical and physical limitations to support plant growth, and improving its matrix properties is crucial to support sustainable vegetation in the long term. Spontaneous vegetation colonization on deposits in Central China, over a period of 20 years, has revealed that natural weathering processes may convert bauxite residue to a soil-like medium. Residue samples from different stacking ages were collected to determine the effect of natural processes on matrix properties over time. It was demonstrated that natural processes decreased pH (10.98 to 9.45), electrical conductivity (EC) (3.73 to 0.36 mS/cm), and exchangeable sodium percentage (ESP) (72.51 to 28.99 %), while increasing bulk density (1.91 to 1.39 g/cm(3)), improving the mean weight diameter (MWD) of water-stable aggregates (0.24 to 0.52 mm), and the proportion of >0.25-mm water-stable aggregates (19.91 to 50.73 %). The accumulation of organic carbon and the reduction of ESP and exchangeable Na had positive effects on soil aggregate formation, while exchangeable Ca and Mg were significantly beneficial to aggregation of water-stable aggregates. Climate, stacking time, and biological factors appear to improve the structure of bauxite residue. Our findings demonstrate soil genesis occurring following natural weathering processes of bauxite residues over time.

  3. Semi-industrial experimental study on bauxite separation using a cellcolumn integration process

    Institute of Scientific and Technical Information of China (English)

    Ning-ning Zhang; Chang-chun Zhou; Long-fei Cong; Wen-long Cao; You Zhou

    2016-01-01

    The cyclonic-static micro-bubble flotation column (FCSMC) is a highly efficient mineral processing equipment. In this study, a cell-column (FCSMC) integration process was investigated for the separation of bauxite and its feasibility was analyzed on a theoretical basis. The properties of low-grade bauxite ore from Henan Province, China were analyzed. Parameters such as reagent dosage, scraping bubble time, and pressure of the circulating pump during the sorting process were investigated and optimized to improve the flotation efficiency. On the basis of these parameters, continuous separation experiments were conducted. Bauxite concentrate with an aluminum-to-silicon (A/S) mass ratio of 6.37 and a 77.63wt% recovery rate were achieved via a flow sheet consisting of “fast flotation using a flotation cell, one roughing flotation and one cleaning flotation using flotation columns”. Compared with the full-flotation-cells process, the cell-column integration process resulted in an increase of the A/S ratio by 0.41 and the recovery rate by 17.58wt%. Cell-column integration separation technology represents a new approach for the separation of middle-to-low-grade bauxite ore.

  4. Semi-industrial experimental study on bauxite separation using a cell-column integration process

    Science.gov (United States)

    Zhang, Ning-ning; Zhou, Chang-chun; Cong, Long-fei; Cao, Wen-long; Zhou, You

    2016-01-01

    The cyclonic-static micro-bubble flotation column (FCSMC) is a highly efficient mineral processing equipment. In this study, a cell-column (FCSMC) integration process was investigated for the separation of bauxite and its feasibility was analyzed on a theoretical basis. The properties of low-grade bauxite ore from Henan Province, China were analyzed. Parameters such as reagent dosage, scraping bubble time, and pressure of the circulating pump during the sorting process were investigated and optimized to improve the flotation efficiency. On the basis of these parameters, continuous separation experiments were conducted. Bauxite concentrate with an aluminum-to-silicon (A/S) mass ratio of 6.37 and a 77.63wt% recovery rate were achieved via a flow sheet consisting of "fast flotation using a flotation cell, one roughing flotation and one cleaning flotation using flotation columns". Compared with the full-flotation-cells process, the cell-column integration process resulted in an increase of the A/S ratio by 0.41 and the recovery rate by 17.58wt%. Cell-column integration separation technology represents a new approach for the separation of middle-to-low-grade bauxite ore.

  5. Separation of diaspore from bauxite by selective flocculation using hydrolyzed polyacrylamide

    Institute of Scientific and Technical Information of China (English)

    刘文莉; 胡岳华; 孙伟

    2014-01-01

    Selective flocculation is a new method to solve the problem of China’s bauxite de-silication besides flotation and reverse flotation. The method of selective flocculation of bauxite using hydrolyzed polyacrylamide as flocculant was experimented and evaluated. The results of diaspore and kaolinite single mineral settling tests show that the difference between settlement yield of kaolinite (settling 15 min) and diaspore (settling 3 min) increases from 16% to 60% by adding flocculant at pH=7. Results of selective flocculation experiment of bauxite show that the higher concentrate grade (65.75) and Al-Si ratio (7.34) could be obtained with sodium carbonate as dispersant compared with sodium hexametaphosphate; under the action of flocculating agent, the concentrate grade and Al-Si ratio increase to 67.99 and 9.01. These results could meet the requirements of Bayer production, and the simpler process was expected to cost far less than traditional flotation method and a promising de-silication method of bauxite.

  6. Beneficiation of Aluminum-, Iron-, and Titanium-Bearing Constituents from Diasporic Bauxite Ores

    Science.gov (United States)

    Li, Guanghui; Gu, Foquan; Jiang, Tao; Luo, Jun; Deng, Bona; Peng, Zhiwei

    2016-12-01

    In this study, extraction of aluminum-, iron-, and titanium-bearing constituents from diaspore-type bauxite ores was investigated by stepwise treatment consisting of pre-desilication via alkali-leaching of bauxite ore, extraction of alumina via Bayer process, and recovery of iron from red mud via magnetic separation. The pre-desilication results showed that the removal of silica reached 73.92% and that the mass ratio of alumina to silica (A/S) of bauxite concentrate increased from 2.92 to 9.25 under the conditions of sodium hydroxide concentration of 50 wt.%, leaching temperature of 95°C, leaching time of 30 min, and liquid-to-solid ratio of 5 mL/g. A total of 96.31% alumina was extracted from the bauxite concentrate via the Bayer process. Subsequently, by using two-step magnetic separation (intensity: 0.8 T and 0.2 T), TiO2-bearing iron concentrate with total iron grade of 56.39% and TiO2 grade of 8.66% was obtained with recoveries of iron and TiO2 of 55.79% and 17.37%, respectively. The grade of TiO2 reached 21.22% in the nonmagnetic fraction.

  7. Effect of Boric Acid on Properties of Calcined Flint Clay-Bauxite Castables

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; DAI Wenyong

    2010-01-01

    In order to prolong the working time of calcined flint clay-bauxite castables during construction at high temperature,boric acid was added into the castables.The effect of boric acid on working time and curing cold crushing strength of the castables at 25 ℃ and 35 ℃were investigated.After 24 h curing in mould and another 24 h curing at 110 ℃ after demoulding,the specimens were heat treated at 1 000 ℃,1 300 ℃,and1 500 ℃ for 3 h,respectively.The permanent linear change,bulk density,modulus of rupture,and cold crushing strength were determined.The result shows that there is no need to add boric acid when calcined flint clay-bauxite ca.stables works at 25 ℃ ; when calcined flint clay-bauxite castables works at 35 ℃,boric acid can increase the working time of the castables,but decrease the curing cold crushing strength a little.Adding boric acid into calcined flint clay-bauxite castables doesn' t worsen performance of the castablcs.

  8. Beneficiation of Aluminum-, Iron-, and Titanium-Bearing Constituents from Diasporic Bauxite Ores

    Science.gov (United States)

    Li, Guanghui; Gu, Foquan; Jiang, Tao; Luo, Jun; Deng, Bona; Peng, Zhiwei

    2017-02-01

    In this study, extraction of aluminum-, iron-, and titanium-bearing constituents from diaspore-type bauxite ores was investigated by stepwise treatment consisting of pre-desilication via alkali-leaching of bauxite ore, extraction of alumina via Bayer process, and recovery of iron from red mud via magnetic separation. The pre-desilication results showed that the removal of silica reached 73.92% and that the mass ratio of alumina to silica (A/S) of bauxite concentrate increased from 2.92 to 9.25 under the conditions of sodium hydroxide concentration of 50 wt.%, leaching temperature of 95°C, leaching time of 30 min, and liquid-to-solid ratio of 5 mL/g. A total of 96.31% alumina was extracted from the bauxite concentrate via the Bayer process. Subsequently, by using two-step magnetic separation (intensity: 0.8 T and 0.2 T), TiO2-bearing iron concentrate with total iron grade of 56.39% and TiO2 grade of 8.66% was obtained with recoveries of iron and TiO2 of 55.79% and 17.37%, respectively. The grade of TiO2 reached 21.22% in the nonmagnetic fraction.

  9. Microbial community succession in alkaline, saline bauxite residue: a cross-refinery study

    Science.gov (United States)

    Santini, T.; Malcolm, L. I.; Tyson, G. W.; Warren, L. A.

    2015-12-01

    Bauxite residue, a byproduct of the Bayer process for alumina refining, is an alkaline, saline tailings material that is generally considered to be inhospitable to microbial life. In situ remediation strategies promote soil formation in bauxite residue by enhancing leaching of saline, alkaline pore water, and through incorporation of amendments to boost organic matter content, decrease pH, and improve physical structure. The amelioration of chemical and physical conditions in bauxite residue is assumed to support diversification of microbial communities from narrow, poorly functioning microbial communities towards diverse, well-functioning communities. This study aimed to characterise microbial communities in fresh and remediated bauxite residues from refineries worldwide, to identify (a) whether initial microbial communities differed between refineries; (b) major environmental controls on microbial community composition; and (c) whether remediation successfully shifts the composition of microbial communities in bauxite residue towards those found in reference (desired endpoint) soils. Samples were collected from 16 refineries and characterised using 16S amplicon sequencing to examine microbial community composition and structure, in conjunction with physicochemical analyses. Initial microbial community composition was similar across refineries but partitioned into two major groups. Microbial community composition changes slowly over time and indicates that alkalinity and salinity inhibit diversification. Microbially-based strategies for in situ remediation should consider the initial microbial community composition and whether the pre-treatment of chemical properties would optimise subsequent bioremediation outcomes. During in situ remediation, microbial communities become more diverse and develop wider functional capacity, indicating progression towards communities more commonly observed in natural grassland and forest soils.

  10. Mineralogy, Geochemistry and Mass Changes at the Mombi Bauxite Deposit, (SW Iran): Using Geochemical Characteristics of the Immobile Elements

    Science.gov (United States)

    Ahmadnejad, Farhad; Vahabzadeh, Bahman; Zamanian, Hassan; Sameti, Mona; Asadi Haroni, Hooshang

    2016-04-01

    The Mombi bauxite deposit is located 160Km northwest of Dehdasht in the Zagros fold belt of Iran. The bauxite horizons are mineralogically homogeneous, and contains high amount of boehmite, diaspore, hematite, kaolinite, and anatase. Total geochemical analysis of the bauxite shows that Al2O3, SiO2, Fe2O3 and TiO2 are the main components. The immobile elements of Al, Ti, Nb, Zr, Hf, Cr, Ta, Y and Th are enriched while Rb, Ba, K, Sr, and P are depleted during bauxitization process. Chondrite-normalized REE pattern in the bauxite ore indicates REE enrichment (ΣREE=162.8-755.28ppm, ave. ~ 399.36 ppm) relative to the argillized limestone (ΣREE=76.26-84.03 ppm, ave. ~ 80.145 ppm). These patterns also reflect enrichment in LREE relative to HREE. Both positive and negative Ce anomalies (0.48-2.0) are observed in the Mombi bauxite horizons. These anomalies are related to the oxidation state of Ce (from Ce3+ to Ce4+), ionic potential, and complication of Ce4+ with carbonate compounds in the studied horizon. The present study uses the geochemistry of immobile elements to calculate the mass changes occurred during weathering and bauxitization. The results reveal that elements such as Si, Fe, Mg, P, K, Ba, Sr and Zn are depleted, while Al, Zr, V, Cr, Ni, Ga, Y and LREEs indicate positive mass changes during the weathering and bauxitization. In addition, Nb, Hf, Ta, Bi, Rb, Cs, U and HRRE exhibit little changes, suggesting relatively immobile features. Inter-elemental relationship analyses of the bauxite by using R-mode factor analysis method suggest that the elemental behaviors of trace elements and REEs during bauxite mineralization are mainly controlled by the mineral compositions and chemical properties of the elements. R-mode factor analysis reveals a number of key findings: (i) some of the low solubility elements were concentrated in detrital zircon (Zr), in anatase (Ti), and possibly in boehmite and hematite during the later stages of bauxitisation; (ii) Fe was

  11. Bauxite-supported Transition Metal Oxides: Promising Low-temperature and SO2-tolerant Catalysts for Selective Catalytic Reduction of NOx

    OpenAIRE

    Xiuyun Wang; Wen Wu; Zhilin Chen; Ruihu Wang

    2015-01-01

    In order to develop low-temperature (below 200 °C) and SO2-tolerant catalysts for selective catalytic reduction (SCR) of NOx, a series of cheap M/bauxite (M = Mn, Ni and Cu) catalysts were prepared using bauxite as a support. Their SCR performances are much superior to typical V2O5/TiO2, the addition of M into bauxite results in significant promotion of NOx removal efficiency, especially at low temperature. Among the catalysts, Cu/bauxite exhibits wide temperature window over 50–400 °C, stron...

  12. Rheological Behavior of Bauxite-Based SiC-Containing Castables

    Institute of Scientific and Technical Information of China (English)

    YE Fangbao; M. Rigaud; LIU Xinhong; ZHONG Xiangchong

    2004-01-01

    Low cement (LC) and ultra-low cement (ULC)bauxite-SiC castables are important and high performance monolithic refiactories andthey have been widely used iniron-making and incinerator linings. In this work, rheo-logical behavior of LC and ULC bauxite-based SiC-contain-ing castables has been studied, including the effects of SiC content and cement content on rheological properties of thecastables. The results show that with an increase of SiC and cement content, rheological properties of the castablesdeteriorate. On the other hand, moderate amounts of SiC(4% ~ 8% ) and of calcium aluminate cement (2% ~4% ) have very slight influence on rheological properties,(i. e. when the castables are sheared their torque andyield torque only slightly increase with the shearing speed). The rheological characteristics of the castables fol-low Bingham fiuid and always show shear thinning behav-ior.

  13. Shifts in leaf N:P stoichiometry during rehabilitation in highly alkaline bauxite processing residue sand.

    Science.gov (United States)

    Goloran, Johnvie B; Chen, Chengrong; Phillips, Ian R; Elser, James J

    2015-10-07

    Large quantities of sodic and alkaline bauxite residue are produced globally as a by-product from alumina refineries. Ecological stoichiometry of key elements [nitrogen (N) and phosphorus (P)] plays a critical role in establishing vegetation cover in bauxite residue sand (BRS). Here we examined how changes in soil chemical properties over time in rehabilitated sodic and alkaline BRS affected leaf N to P stoichiometry of native species used for rehabilitation. Both Ca and soil pH influenced the shifts in leaf N:P ratios of the study species as supported by consistently significant positive relationships (P stoichiometry can effectively provide a meaningful assessment on understanding nutrient limitation and productivity of native species used for vegetating highly sodic and alkaline BRS, and is a crucial indicator for assessing ecological rehabilitation performance.

  14. Ferruginous Microspherules in Bauxite at Maochang, Guizhou Province, China: Products of Microbe-Pyrite Interaction?

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yuefei; WANG Rucheng; LU Jianjun; LI Yiliang

    2006-01-01

    The Maochang bauxite in Guizhou Province is one of the important aluminum ore deposits in southwestern China. Ferruginous spherules, measuring about a few microns across, were found in the transitional layer of the deposit. The EDS and XRD results show that the microspherules are composed mostly of iron (hydr)oxide minerals (goethite) with only weak presence of aluminum and silicon.Occasionally, some pyrite micrograins with dissolved surface are found associated with goethite within the spherules. It is thus suggested that microspherules are linked to pyrite oxidization. It is also thought that microbial activities contribute not only to pyrite oxidization, but also to ball-like assemblage of the iron (hydr)oxides. The mechanism of the formation of ferruginous microspherules is also believed to be important in studying geomicrobiology of bauxite.

  15. Extra large bauxite mines with 120 million tons discovered in Guangxi Congzuo

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>According to Guangxi General Institute of Geological Prospecting,after 3 years of hard work,prospecting team has discovered extra large bauxite mines with resources of 120 mil- lion tons in Youjiang area in Guangxi. It is said that the newly-found extra large baux- ite mines are situated in the city of Congzuo. The ore belt lays generally northeast with 50

  16. Effects of minerals in ferric bauxite on sodium carbonate decomposition and volatilization

    Institute of Scientific and Technical Information of China (English)

    胡文韬; 王化军; 刘欣伟; 孙传尧

    2015-01-01

    Direct reduction is an emerging technology for ferric bauxite utilization. However, because of sodium volatilization, its sodium carbonate consumption is considerably higher than that in ordinary bauxite processing technology. TG-DSC and XRD were applied to detecting phase transformation and mass loss in direct reduction to reveal the mechanism on sodium volatilization. The results show that the most significant influence factor of ferric bauxite on sodium volatilization in direct reduction system is its iron content. Sodium volatilization is probably ascribed to the instability of amorphous substances structure. Amorphous substances are the intermediate-products of the reaction, and the volatilization rate of sodium increases with its generating rate. These amorphous substances are volatile, thus, more sodium is volatilized with its generation. A small amount of amorphous substances are generated in the reaction between Na2CO3and Al2O3; thus, only 3.15% of sodium is volatilized. Similarly, the volatilization rate is 1.87% in the reaction between Na2CO3and SiO2. However, the volatilization rate reaches 7.64% in the reaction between Na2CO3 and Fe2O3 because of the generation of a large amount of amorphous substances.

  17. Artificial neural network prediction of the aluminum extraction from bauxite in the Bayer process

    Directory of Open Access Journals (Sweden)

    Đurić Isidora

    2012-01-01

    Full Text Available This paper presents the results of statistical modeling of the bauxite leaching process, as part of Bayer technology for an alumina production. Based on the data, collected during the period between 2008 - 2009 (659 days from the industrial production in the alumina factory Birač, Zvornik (Bosnia and Herzegovina, the statistical modeling of the above mentioned process was performed. The dependant variable, which was the main target of the modeling procedure, was the degree of Al2O3 recovery from boehmite bauxite during the leaching process. The statistical model was developed as an attempt to define the dependence of the Al2O3 degree of recovery as a function of input variables of the leaching process: composition of bauxite, composition of the sodium aluminate solution and the caustic module of the solution before and after the leaching process. As the statistical modeling tools, Multiple Linear Regression Analysis (MLRA and Artificial Neural Networks (ANNs were used. The fitting level, obtained by using the MLRA, was R2 = 0.463, while ANN resulted with the value of R2 = 0.723. This way, the model, defined by using the ANN methodology, can be used for the efficient prediction of the Al2O3 degree of recovery as a function of the process inputs, under the industrial conditions of the alumina factory Birač, Zvornik. The proposed model also has got a universal character and, as such, is applicable in other factories practicing the Bayer technology for alumina production.

  18. Investigation on deposition condition, sedimentary environment and genesis of Mandan and Deh-Now bauxite deposits, Dehdasht area, Kohgiloye and Boyer-Ahmad province: using mineralogical studies

    Directory of Open Access Journals (Sweden)

    Alireza Zarasvandi

    2011-04-01

    Full Text Available The Mandan and Deh-Now bauxite deposits are located 40 km northeast of Dehdasht in Kohgiloye and Boyer-Ahmad province in the Zagros simply folded belt. The deposits were formed in the oldest rocks of the area of late Cretaceous age. The bauxite horizon is situated between Sarvak and Ilam formations. The aim of this study is to determine the mineralogy and texture relations of the deposits in order to determine the environment and status of bauxite mineralization. In this way, samples were selected from these bauxite deposits for mineralogical studies based on microscopic and XRD techniques. The bauxite horizon in the Mandan deposit consists of white, gray, black, pisolitic, red and yellow bauxites. The sequence was repeated in the Deh-Now without black and gray bauxites. Mineralogy is similar in all bauxitic layers and the main textures are pisolitic-ooide, ooide-spheroid, pisolitic, pelitomorphic and pseoudomorphic. Bohmite, diaspore, kaolinite and calcite are the most important minerals in both bauxitic layers of the Mandan and Deh-Now deposits. Due to bohmite mineralization in the study area, erosional and intense weathering environment in the Touronian-Cenomanian could be suggested for the deposition of bauxite in these deposits. Existence of interclasts in the pisolites and ooides indicate that these bauxites were transformed from the primary in situ environment to karstic sedimentary basin as authigenic origin. These studies indicate that there are two mineralized facies with different environmental status: (1 oxidation facies with bohmite, diaspore, kaolinite and hematite minerals and (2 reduced facies with pyrite, diaspore and chlorite mineralization. The lack of reduced condition at the Deh-Now deposit shows that the deposit formed only in oxidation status.

  19. Caracterização de bauxita ativada antes e depois da saturação com óleo mineral isolante Characterization of activated bauxite before and after saturation with insulating mineral oil

    OpenAIRE

    Josélia Ednar Antunes Piluski; Dachamir Hotza

    2008-01-01

    A characterization of activated bauxite and of activated bauxite impregnated with insulating mineral oil was made. The activated bauxite is used as adsorbent material in percolators during the regeneration of insulating mineral oil. After regeneration an insulating mineral oil is obtained with physical and chemical characteristics similar to those of the new oil. Moreover, saturated activated bauxite impregnated with insulating mineral oil is also produced. It is a dangerous residue according...

  20. Bauxite-supported Transition Metal Oxides: Promising Low-temperature and SO2-tolerant Catalysts for Selective Catalytic Reduction of NOx.

    Science.gov (United States)

    Wang, Xiuyun; Wu, Wen; Chen, Zhilin; Wang, Ruihu

    2015-05-19

    In order to develop low-temperature (below 200 °C) and SO2-tolerant catalysts for selective catalytic reduction (SCR) of NOx, a series of cheap M/bauxite (M = Mn, Ni and Cu) catalysts were prepared using bauxite as a support. Their SCR performances are much superior to typical V2O5/TiO2, the addition of M into bauxite results in significant promotion of NOx removal efficiency, especially at low temperature. Among the catalysts, Cu/bauxite exhibits wide temperature window over 50-400 °C, strong resistance against SO2 and H2O as well as good regeneration ability in SCR of NOx. NOx conversion is more than 80% at 50-200 °C, and N2 selectivity is more than 98%. Cu/bauxite can serve as a promising catalyst in SCR of NOx.

  1. Influence of grazing practices on cow milk quality: a case study on the Comarnic-Poieni bauxite quarry, Romania.

    Science.gov (United States)

    Lorinţ, Csaba; Rădulescu, Monica; Buia, Grigore

    2012-04-01

    The current study represents a preliminary investigation made into the influence of cattle grazing in the area of a bauxite quarry (Comarnic-Poieni, Romania) on the cow milk chemistry. Weathering and surface runoff in the bauxite quarry contaminate the local chemistry of the soil, vegetation and water. During cattle transhumance, cyclic feeding patterns occur, with grazing alternating between clean pastures and the area of the quarry. Soil and water samples were collected from the contaminated area of the quarry. Raw milk samples were collected during two stages, corresponding to the periods of grazing on clean pasture and the quarry area, respectively. Based on the obtained data, the relationship between cattle grazing and the composition of milk was interpreted. Preliminary results indicated a direct correlation of increased concentration of Al in the milk, following grazing in the bauxite quarry.

  2. Characterization of red mud derived from a combined Bayer Process and bauxite calcination method.

    Science.gov (United States)

    Liu, Yong; Lin, Chuxia; Wu, Yonggui

    2007-07-19

    Red mud can be derived from the processing of bauxite using different methods. The chemical and mineralogical composition of the combined Bayer Process and bauxite calcination red mud (BPBCRM) differs markedly from those of the pure Bayer Process red mud (PBPRM). In this study, red mud derived from a combined Bayer Process and bauxite calcination method was characterized. The results show that pH of the red mud decreased with increasing duration of storage time. Na dominated among the soluble cations, but the concentration of soluble Na decreased with increasing duration of storage time as a result of leaching. Cation exchange capacity also decreased with increasing duration of storage time, probably due to a decrease in pH causing a reduction in negatively charged sites on the red mud particles. Ca was the predominant exchangeable cation in the fresh red mud but the concentration of exchangeable Ca markedly decreased in the old red mud, which was dominated by exchangeable Na. The degree of crystallization and thermal stability of the red mud increased with increasing duration of storage. The acid neutralizing capacity of red mud obtained from this study was about 10 mol kg(-1), which is much greater than the reported values for the pure Bayer Process red mud. Column filtering experiment indicates that the red mud also had a very strong capacity to remove Cu, Zn and Cd from the filtering solution. It is conservatively estimated that the simultaneous removal rates of Cd, Zn and Cu by red mud are over 22,250 mg kg(-1), 22,500 mg kg(-1) and 25,000 mg kg(-1), respectively. The affinity of these metals to the red mud was in the following decreasing order: Cu>Zn>Cd. In general, the fresh red mud retained more heavy metals than the old red mud did.

  3. Removal of Pb ion from water samples using red mud (bauxite ore processing waste)

    OpenAIRE

    Ghorbani A.; Nazarfakhari M.; Pourasad Y.; Mesgari Abbasi S.

    2014-01-01

    This work presented the use of red mud (bauxite ore processing waste) in removal of lead ions in water samples. For this 0.1 g of red mud has been used as adsorbent which suspended in 10 ml of lead solution with the concentration of 50 mg l-1 for about 1 h. After that the lead concentration in the samples taken from the red mud treated lead solution measured with atomic absorption spectroscopy (AAS). The effect of some parameter which is important in adsorption of lead on red mud such as suit...

  4. Effect of hydroxamic acid starch on reverse flotation desilicate from diasporic bauxite

    Institute of Scientific and Technical Information of China (English)

    胡岳华; 李海普; 蒋玉仁

    2002-01-01

    It is important to depress diaspore effectively in order to remove silicates from diasporic bauxite. A new water soluble polymer hydroxamic acid starch (HA-starch) was prepared. The effects of the product on the diaspore and kaolinite flotation were investigated and its reactive mechanism was studied by zeta potential measurement and FTIR. The results show that HA-starch can depress diaspore while make positive effect on kaolinite flotation at low pH value(pH below 6). The flotation recovery of diaspore was sharply decreased with the increase of concentration of HA-starch. The chemical adsorption of HA-starch on the surface of diaspore was revealed.

  5. Thermal Shock Resistance of Bauxite-based β-Sialon Bonded Corundum Materials

    Institute of Scientific and Technical Information of China (English)

    LIU Zhanjie; ZHANG Haijun; ZHONG Xiangchong

    2005-01-01

    Thermal shock resistant properties of reaction sintered bauxite-based β-Sialon bonded corundum have been investigated, and the results are compared with those of Al2 O3 based counterpart. It is found they all have very good thermal shock resistance. Their residual strength ratios after one thermal shock cycle at △T =1200℃ and △T = 1350℃ are 61% ~73% and 53% ~65% respectively. Their critical temperature difference (TSR) is 600℃~800℃. TSR parameters are calculated based on thermal expansion, modulus of elasticity,and fracture toughness determined. The reasons for improving TSR of these composite materials are discussed.

  6. Roles of Electrolyte Characterization on Bauxite Electrolysis Desulfurization with Regeneration and Recycling

    Science.gov (United States)

    Gong, Xuzhong; Wang, Zhi; Zhuang, Siyuan; Wang, Dong; Wang, Yuhua; Wang, Mingyong

    2016-10-01

    The recycling of NaCl used as supporting electrolyte for bauxite electrolysis was carried out in this study. The electrolyte was regenerated by adding anhydrous CaCl2 into the solution after filtration, and effects of electrolyte characterization on bauxite electrolysis were examined by observing the change in desulfurization ratio and cell voltage. The results indicated that the desulfurization ratio increased with increasing recycling times of electrolyte. In the meantime, the increase in recycling times has led to the decrease in pH value as well as the increase in Fe ion concentration in the electrolyte, which were the main reasons for the increase in the desulfurization ratio with increasing recycling of electrolyte. The pH value of electrolyte after second electrolysis was lower than 1.5, and the desulfurization ratio increased obviously due to the increase in Fe3+ concentration and suppression of jarosite formation. The increase in Ca2+ concentration did not apparently change desulfurization ratio and anode surface activity. However, with Ca2+ addition, the cathode surface was covered by CaSO4·nH2O, thus resulting in the increase of cell voltage.

  7. Roles of Electrolyte Characterization on Bauxite Electrolysis Desulfurization with Regeneration and Recycling

    Science.gov (United States)

    Gong, Xuzhong; Wang, Zhi; Zhuang, Siyuan; Wang, Dong; Wang, Yuhua; Wang, Mingyong

    2017-02-01

    The recycling of NaCl used as supporting electrolyte for bauxite electrolysis was carried out in this study. The electrolyte was regenerated by adding anhydrous CaCl2 into the solution after filtration, and effects of electrolyte characterization on bauxite electrolysis were examined by observing the change in desulfurization ratio and cell voltage. The results indicated that the desulfurization ratio increased with increasing recycling times of electrolyte. In the meantime, the increase in recycling times has led to the decrease in pH value as well as the increase in Fe ion concentration in the electrolyte, which were the main reasons for the increase in the desulfurization ratio with increasing recycling of electrolyte. The pH value of electrolyte after second electrolysis was lower than 1.5, and the desulfurization ratio increased obviously due to the increase in Fe3+ concentration and suppression of jarosite formation. The increase in Ca2+ concentration did not apparently change desulfurization ratio and anode surface activity. However, with Ca2+ addition, the cathode surface was covered by CaSO4·nH2O, thus resulting in the increase of cell voltage.

  8. Experimental Simulation of Long Term Weathering in Alkaline Bauxite Residue Tailings

    Directory of Open Access Journals (Sweden)

    Talitha C. Santini

    2015-07-01

    Full Text Available Bauxite residue is an alkaline, saline tailings material generated as a byproduct of the Bayer process used for alumina refining. Developing effective plans for the long term management of potential environmental impacts associated with storage of these tailings is dependent on understanding how the chemical and mineralogical properties of the tailings will change during weathering and transformation into a soil-like material. Hydrothermal treatment of bauxite residue was used to compress geological weathering timescales and examine potential mineral transformations during weathering. Gibbsite was rapidly converted to boehmite; this transformation was examined with in situ synchrotron XRD. Goethite, hematite, and calcite all precipitated over longer weathering timeframes, while tricalcium aluminate dissolved. pH, total alkalinity, and salinity (electrical conductivity all decreased during weathering despite these experiments being performed under “closed” conditions (i.e., no leaching. This indicates the potential for auto-attenuation of the high alkalinity and salinity that presents challenges for long term environmental management, and suggests that management requirements will decrease during weathering as a result of these mineral transformations.

  9. The potential for constructed wetlands to treat alkaline bauxite-residue leachate: Phragmites australis growth.

    Science.gov (United States)

    Higgins, D; Curtin, T; Pawlett, M; Courtney, R

    2016-12-01

    High alkalinity (pH > 12) of bauxite-residue leachates presents challenges for the long-term storage and managements of the residue. Recent evidence has highlighted the potential for constructed wetlands to effectively buffer the alkalinity, but there is limited evidence on the potential for wetland plants to establish and grow in soils inundated with residue leachate. A pot-based trial was conducted to investigate the potential for Phragmites australis to establish and grow in substrate treated with residue leachate over a pH range of 8.6-11.1. The trial ran for 3 months, after which plant growth and biomass were determined. Concentrations of soluble and exchangeable trace elements in the soil substrate and also in the aboveground and belowground biomass were determined. Residue leachate pH did not affect plant biomass or microbial biomass. With the exception of Na, there was no effect on exchangeable trace elements in the substrate; however, increases in soluble metals (As, Cd and Na) were observed with increasing leachate concentration. Furthermore, increases in Al, As and V were observed in belowground biomass and for Cd and Cr in aboveground biomass. Concentrations within the vegetation biomass were less than critical phytotoxic levels. Results demonstrate the ability for P. australis to grow in bauxite-residue leachate-inundated growth media without adverse effects.

  10. Separation of aluminosilicates and diaspore from diasporic-bauxite by selective flocculation

    Institute of Scientific and Technical Information of China (English)

    HUANG Chuan-bing; ZHANG Lin; WANG Yu-hua; LAN Ye

    2008-01-01

    The flocculation tests of four pure minerals (diaspore, kaolinite, illite, pyrophyllite) and bauxite ore were investigated by the sedimentation. The dispersion behavior of the four pure minerals shows a very good consistency with the variation of zeta potential. The concentrate with the mass ratio of Al2O3 to SiO2 (m(Al2O3)/m(SiO2)) 8.90 and the recovery of Al2O3 86.98% is obtained from bauxite ore (m(Al2O3)/m(SiO2)=5.68) in pH range of 9.5-10.0 by using sodium carbonate (5 kg/t) and sodium polyacrylate (7 g/t) as dispersant and flocculant respectively. Sodium carbonate acts as both pH modifier and favorable dispersant for aluminosilicates. The high performance of sodium polyacrylate on flocculation for diaspore is contributed to the carboxyl of sodium polyacrylate that interacts with active Al sites on diaspore by chemical absorption, and the hydrogen bond effects between hydroxyl group of macromolecule and surface Al--OH on diaspore to accelerate the sedimentation of diaspore.

  11. The role of nano-perovskite in the negligible thorium release in seawater from Greek bauxite residue (red mud)

    DEFF Research Database (Denmark)

    Gkamaletsos, Platon; Godelitsas, Athanasios; Kasama, Takeshi

    2016-01-01

    We present new data about the chemical and structural characteristics of bauxite residue (BR) from Greek Al industry, using a combination of microscopic, analytical, and spectroscopic techniques. SEM-EDS indicated a homogeneous dominant "Al-Fe-Ca-Ti-Si-Na-Cr matrix", appearing at the microscale. ...

  12. Ação adsorvente da bauxita sobre óleo isolante novo Adsorbing action of bauxite on new insulating oil

    Directory of Open Access Journals (Sweden)

    Geraldo Eduardo da Luz Júnior

    2005-06-01

    Full Text Available Samples of new insulating mineral oil, after contact with bauxite, were analyzed by visible spectrophotometry, impedance spectroscopy and their total acidity index was measured. The results of these analyses were compared to samples of new insulating mineral oil, which had not been in contact with bauxite. The comparison demonstrated that the bauxite didn't reduce the insulating capacity of the mineral oil and thus could be used to treat the oil in situ during the operation of an electric transformer.

  13. Genesis of the Doğankuzu and Mortaş Bauxite deposits, Taurides, Turkey: separation of Al, Fe, and Mn and implications for passive margin metallogeny

    Science.gov (United States)

    Öztürk, Hüseyin; Hein, James R.; Hanilçi, Nurullah

    2002-01-01

    The Taurides region of Turkey is host to a number of important bauxite, Al-rich laterite, and Mn deposits. The most important bauxite deposits, Doğankuzu and Mortaş, are karst-related, unconformity-type deposits in Upper Cretaceous limestone. The bottom contact of the bauxite ore is undulatory, and bauxite fills depressions and sinkholes in the footwall limestone, whereas its top surface is concordant with the hanging-wall limestone. The thickness of the bauxite varies from 1 to 40 m and consists of böhmite, hematite, pyrite, marcasite, anatase, diaspore, gypsum, kaolinite, and smectite. The strata-bound, sulfide- and sulfate-bearing, low-grade lower part of the bauxite ore bed contains pyrite pseudomorphs after hematite and is deep red in outcrop owing to supergene oxidation. The lower part of the bauxite body contains local intercalations of calcareous conglomerate that formed in fault-controlled depressions and sinkholes. Bauxite ore is overlain by fine-grained Fe sulfide-bearing and calcareous claystone and argillaceous limestone, which are in turn overlain by massive, compact limestone of Santonian age. That 50-m-thick limestone is in turn overlain by well-bedded bioclastic limestone of Campanian or Maastrichtian age, rich with rudist fossils. Fracture fillings in the bauxite orebody are up to 1 m thick and consist of bluish-gray-green pyrite and marcasite (20%) with böhmite, diaspore, and anatase. These sulfide veins crosscut and offset the strata-bound sulfide zones. Sulfur for the sulfides was derived from the bacterial reduction of seawater sulfate, and Fe was derived from alteration of oxides in the bauxite. Iron sulfides do not occur within either the immediately underlying or overlying limestone. The platform limestone and shale that host the bauxite deposits formed at a passive margin of the Tethys Ocean. Extensive vegetation developed on land as the result of a humid climate, thereby creating thick and acidic soils and enhancing the transport of

  14. Implementation of reverse flotation method to reduce reactive and non-reactive silica in bauxite ore from West Kalimantan

    Science.gov (United States)

    Wulandari, Winny; Purwasasmita, Mubiar; Sanwani, Edy; Pixelina, Adinda Asri; Maulidan, Agus

    2017-01-01

    This paper reports a study that implements reverse flotation method to separate silica from West Kalimantan bauxite ores. The study is aimed to find the good process condition to obtain low-silica bauxite as the feed for the Bayer process. The experiments were carried out in a 1 L of flotation cell tank. Dodecylamine was used as the collector, starch as the depressant, and MIBC as the frother. The varied parameters were solid content to solution (15-30% w/w), and pH (6 - 10). The results of XRF of products show that in all reverse flotation experiments, the ratio of alumina to silica (Al/Si) are increased from 7 up to 14. The increase of solid percentage in the flotation gives a good result for Al/Si ratio as well as alumina and silica recovery in concentrate, with 30% w/w solid percentage to solution increases Al/Si ratio to 14.38, with silica recovery of 20%. The good separation with variation of depressants is obtained with depressant concentration of 400 g/ton bauxite, with Al/Si ratio in concentrate 15 and ratio in tailing 7. For the pH variation, the good condition is obtained at pH 8, while for collector concentration, the good condition is obtained at 200 g/ton bauxite. XRD analysis of the feed indicates that bauxite ore consists of gibbsite, diaspore, kaolinite, halloysite, quartz, boehmite, hematite and rutile. It is found that the concentrate has similar minerals, but halloysite became very minor or classified as a trace.

  15. Thorium partitioning in Greek industrial bauxite investigated by synchrotron radiation and laser-ablation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Gamaletsos, P. [Faculty of Geology and Geoenvironment, University of Athens, Panepistimioupolis, 15784 Zographou (Greece); Godelitsas, A., E-mail: agodel@geol.uoa.gr [Faculty of Geology and Geoenvironment, University of Athens, Panepistimioupolis, 15784 Zographou (Greece); Mertzimekis, T.J. [Department of Physics, University of Athens, Panepistimioupolis, 15771 Zographou (Greece); Goettlicher, J.; Steininger, R. [Karlsruhe Institute of Technology, Institute for Synchrotron Radiation, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Xanthos, S. [Department of Electrical and Computer Engineering, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); Berndt, J.; Klemme, S. [Institut fuer Mineralogie, Corrensstrasse 24, Universitaet Muenster, 48149 Muenster (Germany); Kuzmin, A. [Institute of Solid State Physics, University of Latvia, Kengaraga st. 8, 1063 Riga (Latvia); Bardossy, G. [Hungarian Academy of Sciences, H-1051 Budapest (Hungary)

    2011-12-15

    Typical red-brown (Fe-rich) and high-quality white-grey (Fe-depleted) bauxite samples from active mines of the Parnassos-Ghiona area, central Greece, were investigated. According to XRF and ICP-MS analyses their actinide content, and particularly of Th, is relatively increased. Fe-depleted samples contain up to 62.75 ppm Th corresponding to 220 Bq/kg due to {sup 228}Ac ({sup 232}Th-series), whereas Fe-rich samples are less Th-radioactive (up to 58.25 ppm Th, 180 Bq/kg due to {sup 228}Ac). Powder-XRD patterns showed that Th-enriched (Fe-depleted) bauxite consists mostly of diaspore (AlOOH polymorph), anatase and rutile (TiO{sub 2} polymorphs). SEM-EDS indicated the presence of Ti-Fe-containing phases (e.g. ilmenite, FeTiO{sub 3}), chromite (Cr-spinel) and besides LREE-minerals (mostly bastnaesite/parisite-group) and zircon (ZrSiO{sub 4}) hosting a part of the bulk Th. The presence of Th in diaspore and in Ti-containing phases (not detected by SEM-EDS as in the case of REE-minerals and zircon) was investigated, into distinct pisoliths of Fe-depleted bauxite, using {mu}-XRF and {mu}-XAFS in the SUL-X beamline of the ANKA Synchrotron facility (KIT, Germany). XAFS spectra of Th salts and Th-containing reference materials were obtained as well. Accordingly it was revealed, for the first time in the literature, that Ti-phases, and particularly anatase, host significant amounts of Th. This novel conclusion was complementary supported by LA-ICP-MS analyses indicated an average of 73 ppm Th in anatase grains together with abundant Nb (3356 ppm), Ta (247 ppm) and U (33 ppm). The Th L{sub III}-edge XAFS spectra as compared to reference materials, give also evidence that Th{sup 4+} may not replace Ti{sup 4+} in distorted [TiO{sub 6}] fundamental octahedral units of anatase and ilmenite lattice (CN = 6). The occupation of either extraframework sites of higher coordination (CN = 6.9 or even CN = 7.4), according to EXAFS signals evaluation, or of defected/vacant (**) sites is more

  16. Thorium partitioning in Greek industrial bauxite investigated by synchrotron radiation and laser-ablation techniques

    Science.gov (United States)

    Gamaletsos, P.; Godelitsas, A.; Mertzimekis, T. J.; Göttlicher, J.; Steininger, R.; Xanthos, S.; Berndt, J.; Klemme, S.; Kuzmin, A.; Bárdossy, G.

    2011-12-01

    Typical red-brown (Fe-rich) and high-quality white-grey (Fe-depleted) bauxite samples from active mines of the Parnassos-Ghiona area, central Greece, were investigated. According to XRF and ICP-MS analyses their actinide content, and particularly of Th, is relatively increased. Fe-depleted samples contain up to 62.75 ppm Th corresponding to 220 Bq/kg due to 228Ac ( 232Th-series), whereas Fe-rich samples are less Th-radioactive (up to 58.25 ppm Th, 180 Bq/kg due to 228Ac). Powder-XRD patterns showed that Th-enriched (Fe-depleted) bauxite consists mostly of diaspore (AlOOH polymorph), anatase and rutile (TiO 2 polymorphs). SEM-EDS indicated the presence of Ti-Fe-containing phases (e.g. ilmenite, FeTiO 3), chromite (Cr-spinel) and besides LREE-minerals (mostly bastnäsite/parisite-group) and zircon (ZrSiO 4) hosting a part of the bulk Th. The presence of Th in diaspore and in Ti-containing phases (not detected by SEM-EDS as in the case of REE-minerals and zircon) was investigated, into distinct pisoliths of Fe-depleted bauxite, using μ-XRF and μ-XAFS in the SUL-X beamline of the ANKA Synchrotron facility (KIT, Germany). XAFS spectra of Th salts and Th-containing reference materials were obtained as well. Accordingly it was revealed, for the first time in the literature, that Ti-phases, and particularly anatase, host significant amounts of Th. This novel conclusion was complementary supported by LA-ICP-MS analyses indicated an average of 73 ppm Th in anatase grains together with abundant Nb (3356 ppm), Ta (247 ppm) and U (33 ppm). The Th LIII-edge XAFS spectra as compared to reference materials, give also evidence that Th 4+ may not replace Ti 4+ in distorted [TiO 6] fundamental octahedral units of anatase and ilmenite lattice (CN = 6). The occupation of either extraframework sites of higher coordination (CN = 6.9 or even CN = 7.4), according to EXAFS signals evaluation, or of defected/vacant (**) sites is more probable. This is likely explained by the difficulty of

  17. An acoustic emission study of cutting bauxite refractory ceramics by abrasive water jets

    Science.gov (United States)

    Momber, A. W.; Mohan, R. S.; Kovacevic, R.

    1999-08-01

    This article discusses the material removal process in bauxite refractory ceramics cut by abrasive water jets. Several parameters of the process were changed during the experiments. The experiments were monitored online by the acoustic emission (AE) technique. It was found that AE signals are able to sense the material removal process as well as the machining performances very reliably. Unsteady material removal mode consisting of matrix removal and intergranular fracture was very well represented in the AE signals by an unsteady time dependent signal type characterized by burst emissions and a frequency domain signal associated with a twin-peak shape. The particular characteristics of the signal depend on the energy involved in the process.

  18. Surface charge properties of red mud particles generated from Chinese diaspore bauxite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Kun-yu; HU Hui-ping; ZHANG Li-juan; CHEN Qi-yuan

    2008-01-01

    Acid/basic potentiometric titration can be used to quantify the red mud surface charge properties. The amount of surface active -OH groups and surface charge density on the red mud particles generated from Chinese diaspore bauxite were evaluated from the acid/basic potentiometric titration data in 0.1 mol/L or 0.5 molL NaCI solution. The results show that the adsorption of sodium polyacrylate(SPA) on the red mud surface causes the increase of the surface active -OH groups, which makes the point of zero charge(PZC) shift to a lower pH value. However, the adsorption of polyacrylamide(PAM) causes little change. As the concentration of NaCl solution increases, the surface charge becomes more positive in acidic solution and more negative in alkaline solution, which can be attributed to the presence of a porous surface gel coating on the red mud particles.

  19. Removal of Pb ion from water samples using red mud (bauxite ore processing waste

    Directory of Open Access Journals (Sweden)

    Ghorbani A.

    2014-07-01

    Full Text Available This work presented the use of red mud (bauxite ore processing waste in removal of lead ions in water samples. For this 0.1 g of red mud has been used as adsorbent which suspended in 10 ml of lead solution with the concentration of 50 mg l-1 for about 1 h. After that the lead concentration in the samples taken from the red mud treated lead solution measured with atomic absorption spectroscopy (AAS. The effect of some parameter which is important in adsorption of lead on red mud such as suitable adsorbent dosage, pH and contact time of solution and adsorbent was investigated. The result shows that red mud as solid waste and low-cost adsorbent can be successfully used for the removal of lead ion from aqueous solution.

  20. Enrichment of Sc2O3 and TiO2 from bauxite ore residues.

    Science.gov (United States)

    Deng, Bona; Li, Guanghui; Luo, Jun; Ye, Qing; Liu, Mingxia; Peng, Zhiwei; Jiang, Tao

    2017-06-05

    As a major byproduct generated in the alumina industry, bauxite ore residue is an important reserve of scandium and titanium. In this study, the feasibility and mechanism of enriching Sc2O3 and TiO2 from a non-magnetic material, which was obtained from carbothermal reductive roasting and magnetic separation of bauxite ore residue, were investigated based on a two-step (acidic and alkali) leaching process. It was revealed that approximately 78% SiO2 and 30-40% of CaO, FeO and Al2O3 were removed from a non-magnetic material with 0.0134wt.% Sc2O3 and 7.64wt.% TiO2 by phosphoric acidic leaching, while about 95% Al2O3 and P2O5 were further leached by subsequent sodium hydroxide leaching of the upper-stream leach residue. A Sc2O3-, TiO2- rich material containing 0.044wt.% Sc2O3 and 25.5wt.% TiO2 was obtained, the recovery and the enrichment factor of Sc2O3 and TiO2 were about 85% and 5, respectively. The enrichment of Sc2O3 was attributed to higher pH (>3.3) of phosphoric acid solution than its dissolution pH(0), and the enrichment of TiO2 was mainly associated with the insoluble perovskite (CaTiO3) in the acidic solution at ambient temperature. As Sc2O3 and TiO2 cannot be dissolved in the alkali solution, they were further enriched in the leach residue.

  1. Caracterização de bauxita ativada antes e depois da saturação com óleo mineral isolante Characterization of activated bauxite before and after saturation with insulating mineral oil

    Directory of Open Access Journals (Sweden)

    Josélia Ednar Antunes Piluski

    2008-01-01

    Full Text Available A characterization of activated bauxite and of activated bauxite impregnated with insulating mineral oil was made. The activated bauxite is used as adsorbent material in percolators during the regeneration of insulating mineral oil. After regeneration an insulating mineral oil is obtained with physical and chemical characteristics similar to those of the new oil. Moreover, saturated activated bauxite impregnated with insulating mineral oil is also produced. It is a dangerous residue according to NBR 10004 (Class I and, thus, harmful to the environment. An alternative use of this waste in the ceramic industry is discussed.

  2. Study on Metallized Reduction and Magnetic Separation of Iron from Fine Particles of High Iron Bauxite Ore

    Science.gov (United States)

    Liu, Zheng-Gen; Chu, Man-Sheng; Wang, Zheng; Zhao, Wei; Tang, Jue

    2017-01-01

    High iron bauxite ore is a typical unmanageable polyparagenetic resource and owns high comprehensive utilization value. Separation of iron from fine particles of high iron bauxite ore by the process of metallized reduction and magnetic dressing was researched systemically. The effect of magnetic field intensity, reduction temperature, reduction time, mole ratio of fixed carbon to reducible oxygen (FC/O) and ore particles size on separation indexes was researched. The results show that, with the conditions of reduction temperature of 1,400 °C, reduction time of 180 min, FC/O of 2.0, ore particle size of -2.0 mm and magnetic field intensity of 40 KA/m, about 89.24 % of the iron could be removed from high iron bauxite ore as metallic iron. Meanwhile, 86.09 % of the aluminum is stayed in non-magnetic fraction as alumina. However, the formation of hercynite (FeAl2O4) limits the reduction rate of iron oxides to metallic iron. The lower reduction conditions and higher recovery ratio of iron could be achieved with adopting ore-coal composite agglomerates or adding catalyst.

  3. Mixed volcanogenic-lithogenic sources for Permian bauxite deposits in southwestern Youjiang Basin, South China, and their metallogenic significance

    Science.gov (United States)

    Yu, Wenchao; Algeo, Thomas J.; Du, Yuansheng; Zhang, Qilian; Liang, Yuping

    2016-07-01

    Bauxite deposits at the base of the Upper Permian Heshan Formation in the Youjiang Basin, South China, contain zircons with dominant age peaks at 263-262 Ma. During the Middle to Late Permian, the Youjiang Basin consisted of a number of isolated and attached carbonate platforms separated by inter-platform troughs. The bauxite deposits are limited to the isolated carbonate platform facies and are not present on attached carbonate platforms and inter-platform troughs. Discriminant plots based on the trace element composition of the zircons indicate a combination of within-plate/anorogenic and arc-related/orogenic sources. Geochemical and isotopic data suggest that the metallogenic materials of the bauxite deposit came from felsic volcanic rocks of the Emeishan Large Igneous Provence (ELIP) in South China and from the Truong Son volcanic arc located between the South China and Indochina cratons. The northwestern and southeastern parts of the Youjiang Basin received larger amounts of ELIP detritus and volcanic arc detritus, respectively. Coarser siliciclastic material in proximal attached carbonate platform and inter-platform trough settings was delivered by rivers, but finer siliciclastics that accumulated on distally located carbonate platforms in isolated deep-water areas was probably transported by wind.

  4. Effect of Raw Bauxite Addition on Thermal Behaviour of Ultra-low Cement Al2O3-SiO2 Castables

    Institute of Scientific and Technical Information of China (English)

    HOU Wanguo; ZHOU Ningsheng

    2009-01-01

    This work investigated the thermo-gravimetric (TG) change and explosion resistance of ultra-low cement Al2O3 -SiO2 castables added with 0, 5%, 10%, 15% and 20% of ≤74 μm raw bauxite powders containing 72. 8% Al2O3, respectively. The castables were prepared using white fused alumina as aggregate, powders of white fused alumina, fused mullite, α-Al2O3 ultrafines, 3% CA cement and 5% microsilica as the matrix portion. TG change of the castables was investi-gated by a thermo-gravimetric analyzer for large size specimen. When the raw bauxite addition is less than 10%, the mass-losing behavior of the castables is simi-lar to that without raw bauxite, tending to reach a con-stant mass around 400 ℃ , before which the mass-loss is mild and producing little destructive influence. With more than 10% raw bauxite addition, however, the mass-loss increases significantly, and the temperature to reach a constant mass increases to 600 ℃ or higher, unfavorable to structural stabilization. With the raw bauxite addition up to 20%, no negative influence on explosion resistance is found.

  5. Evaluation of blends bauxite-calcination-method red mud with other industrial wastes as a cementitious material: Properties and hydration characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Na, E-mail: zhangna06@mails.tsinghua.edu.cn [State Key Lab of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu Xiaoming [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Sun Henghu [School of Engineering and Computer Science, University of the Pacific, Stockton, CA 95211 (United States); Li Longtu [State Key Lab of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2011-01-15

    Red mud is generated from alumina production, and its disposal is currently a worldwide problem. In China, large quantities of red mud derived from bauxite calcination method are being discharged annually, and its utilization has been an urgent topic. This experimental research was to evaluate the feasibility of blends red mud derived from bauxite calcination method with other industrial wastes for use as a cementitious material. The developed cementitious material containing 30% of the bauxite-calcination-method red mud possessed compressive strength properties at a level similar to normal Portland cement, in the range of 45.3-49.5 MPa. Best compressive strength values were demonstrated by the specimen RSFC2 containing 30% bauxite-calcination-method red mud, 21% blast-furnace slag, 10% fly ash, 30% clinker, 8% gypsum and 1% compound agent. The mechanical and physical properties confirm the usefulness of RSFC2. The hydration characteristics of RSFC2 were characterized by XRD, FTIR, {sup 27}Al MAS-NMR and SEM. As predominant hydration products, ettringite and amorphous C-S-H gel are principally responsible for the strength development of RSFC2. Comparing with the traditional production for ordinary Portland cement, this green technology is easier to be implemented and energy saving. This paper provides a key solution to effectively utilize bauxite-calcination-method red mud.

  6. Evaluation of blends bauxite-calcination-method red mud with other industrial wastes as a cementitious material: properties and hydration characteristics.

    Science.gov (United States)

    Zhang, Na; Liu, Xiaoming; Sun, Henghu; Li, Longtu

    2011-01-15

    Red mud is generated from alumina production, and its disposal is currently a worldwide problem. In China, large quantities of red mud derived from bauxite calcination method are being discharged annually, and its utilization has been an urgent topic. This experimental research was to evaluate the feasibility of blends red mud derived from bauxite calcination method with other industrial wastes for use as a cementitious material. The developed cementitious material containing 30% of the bauxite-calcination-method red mud possessed compressive strength properties at a level similar to normal Portland cement, in the range of 45.3-49.5 MPa. Best compressive strength values were demonstrated by the specimen RSFC2 containing 30% bauxite-calcination-method red mud, 21% blast-furnace slag, 10% fly ash, 30% clinker, 8% gypsum and 1% compound agent. The mechanical and physical properties confirm the usefulness of RSFC2. The hydration characteristics of RSFC2 were characterized by XRD, FTIR, (27)Al MAS-NMR and SEM. As predominant hydration products, ettringite and amorphous C-S-H gel are principally responsible for the strength development of RSFC2. Comparing with the traditional production for ordinary Portland cement, this green technology is easier to be implemented and energy saving. This paper provides a key solution to effectively utilize bauxite-calcination-method red mud.

  7. Distribution behavior of collector in the desilication system of bauxite flotation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The distribution behavior of the HZB collector (a kind of long chain fatty acid) in the desilication system of bauxite flotation was studied. The results show that the collector tends towards froth products in the steps of the roughing, the first cleaning and the second cleaning, while towards the tailing product in the step of the scavenging, and in each job except scavenging the collector is mainly on the surface of solids. As for the froth product in the step of the scavenging, it is mainly in solution. To the tailing products of every step, it is mainly in the respective solutions. The collector added to the flotation system is mainly taken out by the last concentrate, by which the taken one occupies 65.2% of the whole, among which, 57.8% is by solid and 7.4% by solution, respectively. And the one by the last tail occupies 34.8% of the whole, among which, 8.8% is by solid and 26.0% by solution, respectively. The sum of the collector in the solution of the last concentrate and tailing is 33.4% of the amount of addition collector, and recycling the solutions will be in favor of decreasing the dosage of collector.

  8. Electroacoustic isoelectric point determinations of bauxite refinery residues: different neutralization techniques and minor mineral effects.

    Science.gov (United States)

    Freire, Tiago S S; Clark, Malcolm W; Comarmond, M Josick; Payne, Timothy E; Reichelt-Brushett, Amanda J; Thorogood, Gordon J

    2012-08-14

    Bauxite refinery residue (BRR) is a highly caustic, iron hydroxide-rich byproduct from alumina production. Some chemical treatments of BRR reduce soluble alkalinity and lower residue pH (to values IEP) determination difficult. Consequently, the IEP of a BRR and five MBRR derivatives (sulfuric acid-, carbon dioxide-, seawater-, a hybrid neutralization, i.e, partial CO(2) neutralization followed by seawater, and an activated-seawater-neutralized MBRR) were determined using electroacoustic techniques. Residues showed three significantly different groups of IEPs (p IEPs were not significantly different from BRR (pH 6.6-6.9). However, neutralizations generating neoformational minerals (alkalinity precipitation) significantly increased the IEP to pH 8.1, whereas activation (a removal of some primary mineralogy) significantly lowered the IEP to pH 6.2. Moreover, surface charging curves show that surfaces remain in the ±30 mV surface charge instability range, which provides an explanation as to why MBRRs remove trace metals and oxyanions over a broad pH range, often simultaneously. Importantly, this work shows that minor mineral components in complex mineral systems may have a disproportionate effect on the observable bulk IEP. Furthermore, this work shows the appropriateness of electroacoustic techniques in investigating samples with significant soluble mineral components (e.g., ANC).

  9. Effects of Polymeric Flocculants on Settlement of Bayer Red Mud Generated from Chinese Diaspore Bauxite

    Institute of Scientific and Technical Information of China (English)

    张琨瑜; 胡慧萍; 张丽娟; 陈启元

    2008-01-01

    A systematic investigation on the interaction between Bayer red mud particles generated from Chinese diaspore bauxite and commercial sodium polyacrylate (SPA) or polyacrylamide (PAM) was performed by red mud settling tests, conductivity-pH titration and Ubbelodhe viscosimetric measurement. The results indicate that the treatment with red mud by SPA gives a lower red mud settling rate and lower supematant turbidity than the treatment with red mud by PAM. There is an optimum polymer dosage of 300 g/t (based on the weight of dry red mud) when red mud slurry is treated by SPA or PAM, so "bridging" adsorption is one of the main interactions between red mud and SPA or PAM. With the increase of NaOH concentration, the hydrolysis degree of PAM dissolved in NaOH solution increases and its molecular weight almost does not change, but the settling rote of red mud treated by it drops rapidly. The settling rate of red mud treated by PAM dissolved in 10 g/L NaOH solution is 0.61 m/h while by PAM dissolved in distilled water it is 1.31 m/h, because the adsorption ability of the hydrolyzed PAM onto red mud surface declines primarily due to the formation of-CONH2~-COO-~-CONH2 intramolecular hydrogen bond.

  10. Surface electrochemical properties of red mud (bauxite residue): zeta potential and surface charge density.

    Science.gov (United States)

    Liu, Yanju; Naidu, Ravendra; Ming, Hui

    2013-03-15

    The surface electrochemical properties of red mud (bauxite residue) from different alumina refineries in Australia and China were studied by electrophoresis and measuring surface charge density obtained from acid/base potentiometric titrations. The electrophoretic properties were measured from zeta potentials obtained in the presence of 0.01 and 0.001 M KNO(3) over a wide pH range (3.5-10) by titration. The isoelectric point (IEP) values were found to vary from 6.35 to 8.70 for the red mud samples. Further investigation into the surface charge density of one sample (RRM) by acid/base potentiometric titration showed similar results for pH(PZC) with pH(IEP) obtained from electrokinetic measurements. The pH(IEP) determined from zeta potential measurements can be used as a characteristic property of red mud. The minerals contained in red mud contributed to the different values of pH(IEP) of samples obtained from different refineries. Different relationships of pH(IEP) with Al/Fe and Al/Si ratios (molar basis) were also found for different red mud samples.

  11. Rapid preparation of ceramic moulds for medium-sized superalloy castings with magnesia-phosphate-bonded bauxite-mullite investments

    Directory of Open Access Journals (Sweden)

    Li Tingzhong

    2010-11-01

    Full Text Available Phosphate-bonded investments have already been widely utilized in dental restoration and micro-casting of artistic products for its outstanding rapid setting and high strength. However, the rapid setting rate of investment slurry has up to now been a barrier to extend the use of such slurry in preparation of medium-sized ceramic moulds. This paper proposes a new process of rapid fabrication of magnesia-phosphate-bonded investment ceramic moulds for medium-sized superalloy castings utilizing bauxite and mullite as refractory aggregates. In order to determine the properties of magnesia-phosphate-bonded bauxite-mullite investments (MPBBMI, a series of experiments were conducted, including modification of the workable time of slurry by liquid(mL/powder(g(L/P ratio and addition of boric acid as retard agent and sodium tri-polyphosphate (STP as strengthening agent, and adjustment of bauxite (g/mullite(g(B/M ratio for mechanical strength. Mechanical vibration was applied to improve initial setting time and fluidity when pouring investment slurry; then an intermediate size ceramic mould for superalloy castings was manufactured by means of this rapid preparing process with MPBBMI material. The results showed that the MPBBMI slurry exhibits proper initial setting time and excellent fluidity when the L/P ratio is 0.64 and the boric acid content is 0.88wt.%. The fired specimens made from the MPBBMI material demonstrated adequate compression strength to withstand impact force of molten metal when the B/M ratio is 0.89 and the STP content is 0.92wt.%. The experimental results confirmed the feasibility of the proposed rapid fabricating process for medium-sized ceramic moulds with MPBBMI material by appropriate measures.

  12. Study of the dielectric parameters of aluminium ore bauxite of Mainpat area of Chhattisgarh at X-band frequency

    Indian Academy of Sciences (India)

    S K Srivastava; B R Vishwakarama

    2004-08-01

    A simple method for measuring the dielectric parameter of materials in the form of powders at microwave frequencies is suggested. Measurement of the permittivity $\\varepsilon'$ and $\\varepsilon''$ at 9.967 GHz on powder samples of the aluminum ore bauxite gives interesting results. It is found that $\\varepsilon'$ and $\\varepsilon''$ increases with packing densities(). Further $\\varepsilon'$ and $\\varepsilon''$ also depend upon the percentage of Al23. These results show that the values of $\\varepsilon'$ and $\\varepsilon''$ can be used to set certain basic values for minability of the ore for a particular sample. Conductivities () and relaxation () are also calculated in the present studies.

  13. Study on the accelerant to the sodium oleate during bauxite flotation

    Institute of Scientific and Technical Information of China (English)

    Liu Sanjun; Hu Yuehua; Qin Wenqing

    2012-01-01

    The conventional collector for diaspore mineral is oleic acid (OLA), which is highly insoluble and must be used in high dosage in bauxite flotation. Firstly flotation experiments with every reagent (sodium oleate, tween-20)were carried out and it was shown that sodium oleate was an effective diaspore collector, whereas nonionic surfactant tween-20 showed little collectivity. Then experiments were carried out with sodium oleate as the main collector with the addition of tween-20 to study the influences of potentiator on diaspore flotation. It could be seen from the experiments that potentiator had a marked influence on the recovery of diaspore, which was raised by more than 12 % and that addition sequence also affected the flotation behavior. It gave the best results with the reagents mixed thoroughly before added and the best ratio of collector oleic acid and potentiator tween-20 slLood at 10: 1. From the calculation of the ingredients in the sodium oleate solution, at the pH 9, sodium oleate acted with surface of the mineral with the acid-soap polymer [ HOL ~ OL- ]. Zeta potential test showed that the potentiator promoted the absorption of collector on the mineral surface, which lowered zeta potential. As could be seen from surface tension experiments, the addition of potentiator tween-20 lowered the CMC ( critical micelle concentration) value of oleic acid solution, which was equivalent to raise the power of the agents. By the adsorptive capability tests, with the addition of tween-20, the adsorption of oleic acid on diaspore got more.

  14. Moengo on strike: The Politics of Labour in Suriname’s Bauxite Industry

    Directory of Open Access Journals (Sweden)

    Anouk de Koning

    2011-10-01

    Full Text Available This article examines one crucial moment of contestation in colonial Suriname, the years 1941- 42, when sustained labour unrest in bauxite town Moengo led to the founding of the first mining unions. It argues that these strikes laid the groundwork for future relations between labour, company and the state and explores the kinds of socio-political alliances that were forged between labour and nationalist politicians on the one hand, and government and transnational company on the other, thereby situating this particular contestation in a larger struggle over a colonial system that aligned itself with metropolitan economic interests.Resumen: Moengo en huelga: Políticas Laborales en la Industria de la Bauxita en SurinameEn este artículo se aborda un momento crucial de la impugnación en el Suriname colonial entre los años 1941-42, cuando un persistente malestar entre los trabajadores del pueblo de la bauxita de Moengo condujo a la fundación de los primeros sindicatos mineros. Se sostiene que esas huelgas sentaron las bases de las futuras relaciones entre el trabajo, las compañías y el estado y se exploran los tipos de alianzas socio-políticas que se forjaron entre políticos laboristas y nacionalistas por un lado, y el gobierno y compañías transnacionales por el otro, situando por ello esta particular impugnación en una lucha de mayor alcance contra un sistema colonial que se identificaba a sí mismo con los intereses económicos metropolitanos.

  15. Recovery of iron and calcium aluminate slag from high-ferrous bauxite by high-temperature reduction and smelting process

    Institute of Scientific and Technical Information of China (English)

    Ying-yi Zhang; Wei L; Yuan-hong Qi; Zong-shu Zou

    2016-01-01

    A high-temperature reduction and smelting process was used to recover iron and calcium aluminate slag from high-ferrous bauxite. The effects of w(CaO)/w(SiO2) ratio, anthracite ratio, and reduction temperature and time on the recovery and size of iron nuggets and on the Al2O3 grade of the calcium aluminate slag were investigated through thermodynamic calculations and experiments. The optimized process conditions were the bauxite/anthracite/slaked lime weight ratio of 100:16.17:59.37, reduction temperature of 1450°C and reduction time of 20 min. Under these conditions, high-quality iron nuggets and calcium aluminate slag were obtained. The largest size and the highest recov-ery rate of iron nuggets were 11.42 mm and 92.79wt%, respectively. The calcium aluminate slag mainly comprised Ca2SiO4 and Ca12Al14O33, with small amounts of FeAl2O4, CaAl2O4, and Ca2Al2SiO7.

  16. An improved implementable process for the synthesis of zeolite 4A from bauxite tailings and its Cr3+ removal capacity

    Science.gov (United States)

    Lei, Peng-cheng; Shen, Xian-jiang; Li, Yang; Guo, Min; Zhang, Mei

    2016-07-01

    A simple and practical method for the synthesis of zeolite 4A from bauxite tailings is presented in this paper. Systematic investigations were carried out regarding the capacity of zeolite 4A to remove Cr(III) from aqueous solutions with relatively low initial concentrations of Cr(III) (5-100 mg·L-1). It is found that the new method is extremely cost-effective and can significantly contribute in decreasing environmental pollution caused by the dumping of bauxite tailings. The Cr(III) removal capacity highly depends on the initial pH value and concentration of Cr(III) in the solution. The maximum removal capacity of Cr(III) was evaluated to be 85.1 mg·g-1 for zeolite 4A, measured at an initial pH value of 4 and an initial Cr(III) concentration of 5 mg·L-1. This approach enables a higher removal capacity at lower concentrations of Cr(III), which is a clear advantage over the chemical precipitation method. The removal mechanism of Cr(III) by zeolite 4A was examined. The results suggest that both ion exchange and the surface adsorption-crystallization reaction are critical steps. These two steps collectively resulted in the high removal capacity of zeolite 4A to remove Cr(III).

  17. Enabling safe dry cake disposal of bauxite residue by deliquoring and washing with a membrane filter press.

    Science.gov (United States)

    Kinnarinen, Teemu; Lubieniecki, Boguslaw; Holliday, Lloyd; Helsto, Jaakko-Juhani; Häkkinen, Antti

    2015-03-01

    Dry cake disposal is the preferred technique for the disposal of bauxite residue, when considering environmental issues together with possible future utilisation of the solids. In order to perform dry cake disposal in an economical way, the deliquoring of the residue must be carried out efficiently, and it is also important to wash the obtained solids well to minimise the amount of soluble soda within the solids. The study presented in this article aims at detecting the most important variables influencing the deliquoring and washing of bauxite residue, performed with a horizontal membrane filter press and by determining the optimal washing conditions. The results obtained from pilot-scale experiments are evaluated by considering the properties of the solids, for instance, the residual alkali and aluminium content, as well as the consumption of wash liquid. Two different cake washing techniques, namely classic washing and channel washing, are also used and their performances compared. The results show that cake washing can be performed successfully in a horizontal membrane filter press, and significant improvements in the recovery of alkali and aluminium can be achieved compared with pressure filtration carried out without washing, or especially compared with the more traditionally used vacuum filtration.

  18. 河南陕县柿树沟铝土矿床控矿地质特征%Geological Characteristics of Shishugou Bauxite Deposit, Henan Province

    Institute of Scientific and Technical Information of China (English)

    陈全树

    2012-01-01

    Shishugou deposits occur in the upper carboniferous Benxi group carbonate unconformity surfaces, and are strictly controlled by sedimentary discontinuous surfaces. The bauxite is large and stable; Orebody is layered or lay-like structure; Ore structure types are massive or layered structures The main mineral compositions are diasporite and kaolinite; The harmful elements are less and associated with gallium elements, etc. Deposits by humid tropical climate change and formation of clay is closely related to mineralization, the different size depressions and dissolved buckets formed on the erosion surfaces are the positioning spaces of the bauxite; The gulf lagoon deposition is favorable conditions for the bauxite bed formation. The deposits belong to main bauxite after short distance handling-machinery sedimentary, and have good bauxite metallogenic prospects.%柿树沟铝土矿床赋存于上石炭统本溪组碳酸盐岩不整合面上,严格受沉积间断面控制.铝土矿规模较大、稳定,矿体为层状或似层状,矿石构造类型为块状、层状.主要矿物成分由一水硬铝石、高岭石组成,有害元素少,并伴生有Ga元素等.矿床受潮湿热带气候中形成的红土化与成矿密切相关,侵蚀面上形成大小不等的洼地及溶斗是铝土矿的定位空间,海湾泻湖相沉积是铝土矿床形成的有利条件.矿床属于经过短距离搬运-机械沉积为主的铝土矿,具有较好的铝土矿成矿前景,

  19. Use of red mud (bauxite residue) for the retention of aqueous inorganic mercury(II).

    Science.gov (United States)

    Rubinos, David A; Barral, María Teresa

    2015-11-01

    The effectiveness of the oxide-rich residue from bauxite refining (red mud) to remove inorganic Hg(II) from aqueous solutions was assessed. The aspects studied comprised the kinetics of the process (t = 1 min-24 h), the effect of pH (3.5-11.5), the interacting effect between salt concentration (0.01-1 M NaNO3) and pH and the Hg(II) sorption isotherm. Hg leaching from spent red mud was evaluated using the toxicity characteristics leaching procedure (TCLP) method. The sorption of Hg(II) onto red mud was very fast, with most of Hg(II) (97.0-99.7%) being removed from 0.5-50 μM Hg solutions in few minutes. The kinetic process was best described by Ho's pseudo-second order equation, pointing to chemisorption as the rate controlling step. Hg(II) sorption efficiency was very high (% removal between 93.9 and 99.8%) within all the studied pH range (3.5-11.5) and added Hg concentrations (5 and 50 μM), being optimal at pH 5-8 and decreasing slightly at both lowest and highest pH. The effect of background electrolyte concentration suggests specific sorption as the main interaction mechanism between Hg(II) and red mud, but the increasing non-sorbed Hg concentrations at low and high pH for higher electrolyte concentrations also revealed the contribution of an electrostatic component to the process. The sorption isotherm showed the characteristic shape of high affinity sorbents, and it was better described by the Redlich-Peterson and Freundlich equations, which are models that assume sorbent heterogeneity and involvement of more than one mechanism. The estimated Hg(II) sorption capacity from the Langmuir equation (q m ~9 mmol/kg) was comparable to those of some inorganic commercial sorbents but lower than most bio- or specifically designed sorbents. The leachability of retained Hg(II) from spent red mud (0.02, 0.25 and 2.42 mmol Hg/kg sorbed concentration) was low (0.28, 1.15 and 2.23 μmol/kg, respectively) and accounted for 1.2, 0.5 and 0.1% of previously sorbed Hg

  20. Arsenic stabilization by zero-valent iron, bauxite residue, and zeolite at a contaminated site planting Panax notoginseng.

    Science.gov (United States)

    Yan, X L; Lin, L Y; Liao, X Y; Zhang, W B; Wen, Y

    2013-10-01

    Panax notoginseng (Burk.) F.H. Chen, a rare traditional Chinese medicinal herb, is a widely used phytomedicine used all over the world. In recent years, the arsenic contamination of the herb and its relative products becomes a serious problem due to elevated soil As concentration. This study aimed to evaluate the effects of different types and dosages of amendments on As stabilization in soil and its uptake by P. notoginseng. Results showed that comparing to control treatment, the As concentrations of P. notoginseng declined by 49-63%, 43-61% and 52-66% in 0.25% zero-valent iron (Fe(0)), 0.5% bauxite residue, and 1% zeolite treatment, respectively; whereas the biomasses were elevated by 62-116%, 45-152% and 114-265%, respectively. The As(III) proportions of P. notoginseng increased by 8%, 9%, and 8%, and the transfer factors of As from root to shoot increased by 37%, 42% and 84% in the optimal treatments of Fe(0), bauxite residue, and zeolite. For soil As, all the three amendments could transform the non-specifically adsorbed As fraction to hydrous oxides Fe/Al fractions (by Fe(0) and red mud) or specifically adsorbed As fraction (by zeolite), therefore reduced the bioavailability of soil As. With a comprehensive consideration of stabilization efficiency, plant growth, environmental influence, and cost, Fe(0) appeared to be the best amendment, and zeolite could also be a good choice. In conclusion, this study was of significance in developing As contamination control in P. notoginseng planting areas, and even other areas for medicinal herb growing.

  1. Analysis on used bauxite based brick in torpedo ladle of Pangang,%攀钢铁水罐用后高铝残砖分析

    Institute of Scientific and Technical Information of China (English)

    韩兵强; 王长民; 杨强; 高钦; 李楠

    2011-01-01

    利用化学分析、X射线衍射仪、电子探针以及热力学等方法对攀钢铁水罐用后高铝残砖进行了分析.结果表明:残砖几乎没有挂渣层.舍钒钛渣由于表面张力小,黏度低,在高铝砖中的渗透很深;渣中的V2O5、TiO2、MnO、FeO等与高铝砖中组分反应生成的固溶体和化合物(如尖晶石、刚玉、钙长石等)中均发现固溶有V2O5;变质层的形成导致了致密化热震剥落;而较高的气孔率也是高铝砖损毁严重的另一重要原因.%Used bauxite based brick in torpedo ladle of Pangang Group Co., Ltd.was analyzed by means of ICPAES,XRD,EPMA,and thermodynamics.The results show that: (1)there is hardly any slag layer adhering on the used brick; (2)the vanadium and titanium containing slag penetrates into the bauxite based brick deeply because of low surface tension and viscosity;(3)V2O5 is found in the solid solution and compounds (such as spinel,corundum,and anorthite) formed by the reactions of V2O5,TiO2,MnO,and FeO in slag with the components of bauxite based brick; (4)the formation of deteriorated layer leads to the densification thermal shock spalling; (5)high porosity is another key reason for the serious damage of bauxite based brick.

  2. Using one waste to tackle another: Preparation of a CO{sub 2} capture material zeolite X from laterite residue and bauxite

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Liying [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Du, Tao, E-mail: dutao0106@gmail.com [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Li, Gang [School of Mechanical and Chemical Engineering, The University of Western Australia, Crawley, WA 6009 (Australia); Yang, Fan; Che, Shuai [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China)

    2014-08-15

    Highlights: • Valuable zeolite X has been synthesized from laterite residue and bauxite. • High product purity has been achieved by optimizing the process conditions. • Prepared zeolite X shows comparable gas adsorption properties to commercial ones. • Prepared zeolite X can be used for carbon capture by vacuum swing adsorption. - Abstract: In this work, zeolite X, a benchmark adsorbent for carbon capture, has been successfully prepared from low cost waste minerals namely laterite residue and bauxite using alkali fusion process followed by hydrothermal treatment. The structure and morphology of the as-synthesized zeolite X were verified and characterized with a range of experimental techniques such as X-ray diffraction, scanning electronic microscopy and infrared spectroscopy. The surface area and (N{sub 2} and CO{sub 2}) gas adsorption isotherms of this product were found comparable to that of commercial ones, demonstrating the effectiveness of synthesizing zeolite X from laterite and bauxite. Further improvement of the product purity was also accomplished by optimizing the process conditions.

  3. On the Origin of Bastnaesite-(La,Nd,Y in the Nissi (Patitira Bauxite Laterite Deposit, Lokris, Greece

    Directory of Open Access Journals (Sweden)

    Sofia Kalatha

    2017-03-01

    Full Text Available A detailed geochemical study and a thorough mineralogical description of the rare-earth elements (REE-minerals and associated minerals were carried out in two vertical profiles of approximately 4 m length, from the Nissi (Patitira bauxite laterite deposit, Lokris, Greece, characterized by the presence of goethite in small sizes resembling bacterial cell coated by goethite and a significant REE enrichment. The enrichment of the REE concentrated in bastnaesite-group minerals, the intergrowths between REE-minerals and Al–Ni–silicates with significant sulfur contents and their association with goethite microtextures interpreted as bacteriomorphic, indicate REE remobilization along with iron bio-leaching and re-precipitation on karstified limestone. In addition to the previous-reported hydroxylbastnaesites, a (La,Nd,Y(CO3F member of the bastnaesite-group associated with Al–Ni–silicates were identified, the stability of which may reflect the dependence on the source rocks and the local variations of pH-Eh. Interaction between downward percolating water and carbonate rocks seems to be a very effective mechanism for REE fluorocarbonates deposition under alkaline and reducing conditions.

  4. The role of nano-perovskite in the negligible thorium release in seawater from Greek bauxite residue (red mud)

    Science.gov (United States)

    Gamaletsos, Platon N.; Godelitsas, Athanasios; Kasama, Takeshi; Kuzmin, Alexei; Lagos, Markus; Mertzimekis, Theo J.; Göttlicher, Jörg; Steininger, Ralph; Xanthos, Stelios; Pontikes, Yiannis; Angelopoulos, George N.; Zarkadas, Charalampos; Komelkov, Aleksandr; Tzamos, Evangelos; Filippidis, Anestis

    2016-01-01

    We present new data about the chemical and structural characteristics of bauxite residue (BR) from Greek Al industry, using a combination of microscopic, analytical, and spectroscopic techniques. SEM-EDS indicated a homogeneous dominant “Al-Fe-Ca-Ti-Si-Na-Cr matrix”, appearing at the microscale. The bulk chemical analyses showed considerable levels of Th (111 μg g−1), along with minor U (15 μg g−1), which are responsible for radioactivity (355 and 133 Bq kg−1 for 232Th and 238U, respectively) with a total dose rate of 295 nGy h−1. Leaching experiments, in conjunction with SF-ICP-MS, using Mediterranean seawater from Greece, indicated significant release of V, depending on S/L ratio, and negligible release of Th at least after 12 months leaching. STEM-EDS/EELS & HR-STEM-HAADF study of the leached BR at the nanoscale revealed that the significant immobility of Th4+ is due to its incorporation into an insoluble perovskite-type phase with major composition of Ca0.8Na0.2TiO3 and crystallites observed in nanoscale. The Th LIII-edge EXAFS spectra demonstrated that Th4+ ions, which are hosted in this novel nano-perovskite of BR, occupy Ca2+ sites, rather than Ti4+ sites. That is most likely the reason of no Th release in Mediterranean seawater. PMID:26899139

  5. The role of nano-perovskite in the negligible thorium release in seawater from Greek bauxite residue (red mud)

    Science.gov (United States)

    Gamaletsos, Platon N.; Godelitsas, Athanasios; Kasama, Takeshi; Kuzmin, Alexei; Lagos, Markus; Mertzimekis, Theo J.; Göttlicher, Jörg; Steininger, Ralph; Xanthos, Stelios; Pontikes, Yiannis; Angelopoulos, George N.; Zarkadas, Charalampos; Komelkov, Aleksandr; Tzamos, Evangelos; Filippidis, Anestis

    2016-02-01

    We present new data about the chemical and structural characteristics of bauxite residue (BR) from Greek Al industry, using a combination of microscopic, analytical, and spectroscopic techniques. SEM-EDS indicated a homogeneous dominant “Al-Fe-Ca-Ti-Si-Na-Cr matrix”, appearing at the microscale. The bulk chemical analyses showed considerable levels of Th (111 μg g-1), along with minor U (15 μg g-1), which are responsible for radioactivity (355 and 133 Bq kg-1 for 232Th and 238U, respectively) with a total dose rate of 295 nGy h-1. Leaching experiments, in conjunction with SF-ICP-MS, using Mediterranean seawater from Greece, indicated significant release of V, depending on S/L ratio, and negligible release of Th at least after 12 months leaching. STEM-EDS/EELS & HR-STEM-HAADF study of the leached BR at the nanoscale revealed that the significant immobility of Th4+ is due to its incorporation into an insoluble perovskite-type phase with major composition of Ca0.8Na0.2TiO3 and crystallites observed in nanoscale. The Th LIII-edge EXAFS spectra demonstrated that Th4+ ions, which are hosted in this novel nano-perovskite of BR, occupy Ca2+ sites, rather than Ti4+ sites. That is most likely the reason of no Th release in Mediterranean seawater.

  6. Hydration mechanism and leaching behavior of bauxite-calcination-method red mud-coal gangue based cementitious materials.

    Science.gov (United States)

    Zhang, Na; Li, Hongxu; Liu, Xiaoming

    2016-08-15

    A deep investigation on the hydration mechanism of bauxite-calcination-method red mud-coal gangue based cementitious materials was conducted from viewpoints of hydration products and hydration heat analysis. As a main hydration product, the microstructure of C-A-S-H gel was observed using high resolution transmission electron microscopy. It was found that the C-A-S-H gel is composed of amorphous regions and nanocrystalline regions. Most of regions in the C-A-S-H gel are amorphous with continuous distribution, and the nanocrystalline regions on scale of ∼5nm are dispersed irregularly within the amorphous regions. The hydration heat of red mud-coal gangue based cementitious materials is much lower than that of the ordinary Portland cement. A hydration model was proposed for this kind of cementitious materials, and the hydration process mainly consists of four stages which are dissolution of materials, formation of C-A-S-H gels and ettringite, cementation of hydration products, and polycondensation of C-A-S-H gels. There are no strict boundaries among these four basic stages, and they proceed crossing each other. Moreover, the leaching toxicity tests were also performed to prove that the developed red mud-coal gangue based cementitious materials are environmentally acceptable.

  7. Environment-oriented low-cost porous mullite ceramic membrane supports fabricated from coal gangue and bauxite

    Energy Technology Data Exchange (ETDEWEB)

    Lü, Qikai [Institute of Urban Environment, Chinese Academy of Sciences, Xiamen (China); Ningbo Urban Environment Observation and Research Station-NUEORS, Chinese Academy of Sciences, Ningbo (China); School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou (China); Dong, Xinfa [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou (China); Zhu, Zhiwen [Institute of Urban Environment, Chinese Academy of Sciences, Xiamen (China); Ningbo Urban Environment Observation and Research Station-NUEORS, Chinese Academy of Sciences, Ningbo (China); Dong, Yingchao, E-mail: ycdong@iue.ac.cn [Institute of Urban Environment, Chinese Academy of Sciences, Xiamen (China); Ningbo Urban Environment Observation and Research Station-NUEORS, Chinese Academy of Sciences, Ningbo (China)

    2014-05-01

    Highlights: • Coal gangue was recycled to fabricate low-cost porous mullite membrane supports. • A unique volume-expansion occurred due to a mullitization-crystal-growth process. • A porous structure consists of glassy particles and embedded mullite crystals. - Abstract: Porous mullite ceramic supports for filtration membrane were successfully fabricated via recycling of coal gangue and bauxite at sintering temperatures from 1100 to 1500 °C with corn starch as pore-forming agent. The dynamic sintering behaviors, phase evolution, shrinkage, porosity and pore size, gas permeation flux, microstructure and mechanical property were systematically studied. A unique volume-expansion stage was observed at increased temperatures from 1276 to 1481 °C caused by a mullitization-crystal-growth process. During this stage, open porosity increases and pore size distributions broaden, which result in a maximum of nitrogen gas flux at 1400 °C. The X-ray diffraction results reveal that secondary mullitization took place from 1100 °C and the major phase is mullite with a content of ∼84.7 wt.% at 1400 °C. SEM images show that the as-fabricated mullite supports have a porous microstructure composed of sintered glassy particles embedded with inter-locked mullite crystals, which grew gradually with increasing temperature from rod-like into blocky-like morphologies. To obtain mullite membrane supports with sufficient porosity and acceptable mechanical strength, the relationship between porosity and mechanical strength was investigated, which was fitted using a parabolic equation.

  8. 试论遵义高铁铝土矿与低铁铝土矿的分带性及形成机制%The zonation and genetic mechanism of Zunyi high-and low-ferrous bauxites

    Institute of Scientific and Technical Information of China (English)

    刘平; 廖友常

    2013-01-01

    遵义铝土矿带早石炭世沉积型铝土矿及其含铝岩系,皆沉积-堆积在紫云运动(晚泥盆世至早石炭世)时期形成的略微向南倾斜的夷平面上,其中的高铁铝土矿与低铁铝土矿具有明显分带性.铝土矿及其含矿岩系的原始物质,主要是由下奥陶统湄潭组伊利石页岩形成的含三水铝石的红土风化壳.铝土矿的分带性与红土风化壳物质搬运的距离有关,近处、高处为高铁铝土矿,远处、低处为低铁铝土矿.总体来看,搬运距离较短,属近源搬运、沉积-堆积而成的.%Early Carbonaceous sedimentary bauxite and its aluminum-bearing rock series in the Zunyi bauxite belt have totally undergone sedimentation-accumulation on the slightly southward inclined plantation formed during the late Devonian and Early Carbonaceous Ziyun movement,and the high-and low-ferrous bauxites apparently assume zonation.Original materials of bauxites and the ore-bearing rock series consist dominantly of gibbsite laterite crust formed by illite shale of the Lower Ordovician Meitan Formation.The zonation of bauxite is related to the material-transport distance of the laterite crust,i.e.,the high-ferrous bauxites occur in nearby and high places,and the low-ferrous bauxites appear in distant and low places.Generally speaking,the transport distance is relatively short? and the bauxites were formed by the near-source transport,sedimentation and accumulation.

  9. Contrasting physiological responses of two co-occurring eucalypts to seasonal drought at restored bauxite mine sites.

    Science.gov (United States)

    Szota, Christopher; Farrell, Claire; Koch, John M; Lambers, Hans; Veneklaas, Erik J

    2011-10-01

    This study describes the physiological response of two co-occurring tree species (Eucalyptus marginata and Corymbia calophylla) to seasonal drought at low- and high-quality restored bauxite mine sites in south-western Australia. Seasonal changes in photosynthesis (A), stomatal conductance (g(s)), leaf water potential (ψ), leaf osmotic potential (ψ), leaf relative water content (RWC) and pressure-volume analysis were captured over an 18-month field study to (i) determine the nature and severity of physiological stress in relation to site quality and (ii) identify any physiological differences between the two species. Root system restriction at the low-quality site reduced maximum rates of gas exchange (g(s) and A) and increased water stress (midday ψ and daily RWC) in both species during drought. Both species showed high stomatal sensitivity during drought; however, E. marginata demonstrated a higher dehydration tolerance where ψ and RWC fell to -3.2 MPa and 73% compared with -2.4 MPa and 80% for C. calophylla. Corymbia calophylla showed lower g(s) and higher ψ and RWC during drought, indicating higher drought tolerance. Pressure-volume curves showed that cell-wall elasticity of E. marginata leaves increased in response to drought, while C. calophylla leaves showed lower osmotic potential at zero turgor in summer than in winter, indicating osmotic adjustment. Both species are clearly able to tolerate seasonal drought at hostile sites; however, by C. calophylla closing stomata earlier in the drought cycle, maintaining a higher water status during drought and having the additional mechanism of osmotic adjustment, it may have a greater capacity to survive extended periods of drought.

  10. Characteristics of ethylene glycol-Al2O3 nanofluids prepared by utilizing Al2O3 nanoparticles synthesized from local bauxite

    Science.gov (United States)

    Syarif, D. G.

    2016-11-01

    Nanoparticles of Al2O3 have been synthesized from local bauxite mineral, and ethylene glycol (EG)-Al2O3 nanofluids have been prepared. Powder Al(OOH) was extracted from local bauxite using bayer process, and heated at 600°C for 3 hours to get Al2O3 nanoparticles. XRD analyses showed that the Al2O3 nanoparticles crystallizes in γ-Al2O3 with crystallite size of 4.12 nm. The specific surface area of the ACO3 nanoparticles was 296.72 m2/gr. Viscosity of the EG-Al2O3 nanofluids was temperature dependent, and decreased with increasing temperature. The viscosity of the nanofluids increased with the concentration of the Al2O3 nanoparticles. Meanwhile, Critical Heat Flux (CHF) enhancement of the nanofluids increased with the concentration of the Al2O3 nanoparticles. The largest CHF enhancement was 54% at Al2O3 concentration of 0.095 vol %.

  11. Amelioration of bauxite residue sand by intermittent additions of nitrogen fertiliser and leaching fractions: The effect on growth of kikuyu grass and fate of applied nutrients.

    Science.gov (United States)

    Kaur, Navjot; Phillips, Ian; Fey, Martin V

    2016-04-15

    Bauxite residue, a waste product of aluminium processing operations is characterised by high pH, salinity and exchangeable sodium which hinders sustainable plant growth. The aim of this study was to investigate the uptake form, optimum application rate and timing of nitrogen fertiliser to improve bauxite residue characteristics for plant growth. Kikuyu grass was grown in plastic columns filled with residue sand/carbonated residue mud mixture (20:1) previously amended with gypsum, phosphoric acid and basal nutrients. The experiment was set up as a 4×4 factorial design comprising four levels of applied nitrogen (N) fertiliser (0, 3, 6 and 12mgNkg(-1) residue) and four frequencies of leaching (16, 8 and 4day intervals). We hypothesised that the use of ammonium sulfate fertiliser would increase retention of N within the rhizosphere thereby encouraging more efficient fertiliser use. We found that N uptake by kikuyu grass was enhanced due to leaching of excess salts and alkalinity from the residue profile. It was also concluded that biomass production and associated N uptake by kikuyu grass grown in residue is dependent on the type of fertiliser used.

  12. Analysis of the global trade of bauxite and alumina%全球铝土矿及氧化铝贸易状况分析

    Institute of Scientific and Technical Information of China (English)

    周园园; 王京; 唐萍芝

    2016-01-01

    本文分析了2014年全球铝土矿和氧化铝进出口情况以及主要进口国和出口国的历史数据.全球铝土矿出口国和进口国分布集中;氧化铝出口国集中,进口国则相对分散.并在此基础上研究了世界铝土矿和氧化铝贸易流向,南美、西非和澳洲是全球原材料供应中心,北美、欧洲和中国是全球需求中心.%This paper analyzes the exports and imports of global bauxite and alumina by 2014,and the historical data of importing and exporting countries. The global exporting and importing countries exported concentrated;The exporter countries of alumina concentrated,but the importing country dispersioned. Based on this study,we research the world's bauxite and alumina trade flows,Latin America,West Africa and Oceania is the world's supply center,North America and Asia is the center of global demand.

  13. DEGRADATION OF BAUXITE WITH COMPLICATE MINERAL COMPOSITIONS BY MICROORGANISMS IN CULTURE EXPERIMENTS%组成复杂铝土矿微生物风化作用模拟试验

    Institute of Scientific and Technical Information of China (English)

    孙德四; 陈晔; 曹飞

    2012-01-01

    A strain of silicate bacteria isolated from the surface of bauxite was chosen to carry out a study on the microbial degradation of bauxite with complicate mineral compositions. Bauxite was incubated in nitrogen-free medium containing silicate bacteria. During shaking incubation,the concentrations of main impurity elements containing in bauxite such as aluminum,silicon,ferrum, calcium were measured in the weathering medium, and bauxite samples were collected and analyzed by X-ray diffraction and electron microscope. The results showed that the bacteria indeed e-roded the surface of bauxite,and obviously formed the mycelium-mineral complex between silicate bacteria and mineral powder with the extension of shaking culture time. Furthermore,silicate bacteria selectively degraded different minerals containing in bauxite due to difference in mineral crystal structure. Kaolinite and illite with layer structure were more easily decomposed than quartz with framework structure by bacteria. The stain can release Al,Si,Fe,Ca,K from bauxite to the culture medium, and the percentage compositions of Ca in the bauxite surface decreased from 19. 44 to 1. 91,and those of Fe,K form 1. 70,1. 28 to trace after bauxite interaction with bacteria. The mechanisms of mineral degradation by silicate bacteria were also discussed.%选用一株从铝土矿样表面分离的硅酸盐细菌,研究了该菌株对矿物种类与组成复杂的铝土矿的风化作用.通过摇瓶培养,使硅酸盐细菌在培养液中与矿物颗粒发生相互作用,再测定不同发酵时间上清液中主要杂质元素的含量,并对细菌作用不同时间后的铝土矿进行电镜观察和电子能谱扫描及X射线衍射分析.结果表明,随着培养时间的延长,发酵液中形成了明显的菌体-矿物复合体,细菌对矿物表面产生了溶蚀作用;细菌对不同晶体结构的矿物具有选择性破坏作用,层状结构的高岭石、伊利石比架状结构的石英等矿物更容

  14. Thin Layer Chromatographic Study of Bauxite and Quantitative Estimation of Co-Existing Al3+, Fe2+ and Ti4+%薄层色谱法测定铝土矿中的主成分及其共存离子Al3+,Fe2+和Ti4+

    Institute of Scientific and Technical Information of China (English)

    MOHAMED NAJAR P A; JEURKAR J U; RAMANA RAO K V

    2005-01-01

    Thin layer chromatography in combination with spectrophotometry and titrimetry has been used to evaluate chromatographic characteristics of bauxite constituents. The retention behaviors of four major constituents (Al3+, Fe2+, Ti4+, Si4+) in bauxite mineral have been examined on plain and modified layers of silica gel G, silica gel H and cellulose with mobile phases containing aqueous sodium chloride, formic acid and hydrochloric acid. Ternary separation of Al-Fe-Ti was achieved on chromatographic plates made of silica gel H. The Ph effect and presence of impurity elements in samples, nature of stationary phases on the ternary separation and detection limits of bauxite constituents were studied. Silicon in bauxite was detected on cellulose plates. Quantitative determinations of Al3+, Fe2+ and Ti4+ on silica gel H impregnated with sodium formate layers were achieved by titrimetry and spectrophotometry.

  15. Effects of CeO2 on structure and properties of Ni-Mn-K/bauxite catalysts for water-gas shift reaction

    Institute of Scientific and Technical Information of China (English)

    JIANG Lilong; YE Binghuo; WEI Kemei

    2008-01-01

    Multiple-metal catalysts (Ni-Mn-Ce-K/bauxite) for Water-Gas Shift (WGS) reaction were prepared by impregnation, and the catalytic structure and properties were investigated by N2 physical, XRD, H2-TPR, and CO-TPD. The results indicated that the addition of 7.5% CeO2 improved the activity of the WGS reaction obviously, and also increased the specific surface area and pore volume of the catalysts. The addition of CeO2 decreases the reduction temperature, enhanced the adsorption and activation of H2O, and improved the adsorption content of CO. Besides, active sites were not changed and the number of active sites on catalysts did not increase obviously.

  16. Experimental study on feasibility of gravity separation of a low-grade bauxite ore%某低品位铝土矿的重选可行性试验研究

    Institute of Scientific and Technical Information of China (English)

    盖艳武; 丁行标; 刘敏; 孙利青

    2012-01-01

    The low-grade bauxite ore from Henan province whose mass ratio of aluminium oxide to silicon dioxide was about three was taken as study object. After float-sink experiment, a shaking table and a teetered bed separator were used to conduct expriments so as to investigate if gravity separation of the bauxite ore was feasible. Finally, the concentrate whose mass ratio of aluminium oxide to silicon dioxide was about six was obtained. The study results showed that the gravity separation was of significance for separation of the low-grade bauxite ore.%以河南某铝硅比为3左右的低品位铝土矿为研究对象,在浮沉试验的基础上,通过摇床分选、干扰分选床(TBS)分选,对该低品位铝土矿的重选可行性进行试验研究,获得了铝硅比为6左右的精矿。研究结果表明,重选对该低品位铝土矿的分选具有重要的意义。

  17. 用废铝渣制备膨胀和自应力硫铝酸盐水泥的研究%Preparation of Expansive and Self-stressing Sulphoaluminate Cement Using Bauxite Waste

    Institute of Scientific and Technical Information of China (English)

    冯庆革; 邱树恒; 杨义; 陈明源; 程伟

    2007-01-01

    In this study, bauxite waste was used instead of bauxite to produce sulphoaluminate clinker. With orthogonal design the technical parameters, for production of sulphoaluminate clinker were studied. Expansive and self-stressing sulphoaluminate cements were prepared using the clinkers produced by varying the added amount of gypsum. The results show that: (1) Using bauxite waste to make sulphoaluminate cement is feasible;(2) The optimum condition for the production of clinker are N= 3.9, P= 2.8, Cm= 0.99 and Tb =1350 ℃;(3) The physical properties of the prepared cement conform to the standard of self-stressing and expansive cement.%通过正交试验设计,研究了用废铝渣替代铝矾土制备硫铝酸盐水泥熟料,调整石膏掺量制备膨胀和自应力水泥.研究结果表明:①用废铝渣替代铝矾土制备硫铝酸盐水泥熟料是可行的;②最佳熟料煅烧条件为N = 3.9, P = 2.8, Cm = 0.99 和煅烧温度 Tb =1350 ℃;③制备的水泥物理性能符合膨胀和自应力水泥国家标准.

  18. Experimental Observations of the Patterns of Fungi-Mineral Surfaces Interactions with Muscovite, Biotite, Bauxite, Chromite, Hematite, Galena, Malachite, Manganite and Carbonate Substrates.

    Science.gov (United States)

    Claeys, P.

    2006-12-01

    In an in vitro experimental work, mineral substrates of muscovite, biotite, bauxite, chromite, hematite, galena, malachite, manganite and carbonate were exposed to free fungal growth and interaction in Petri dishes under open conditions. All of the experimental minerals were examined by XRD for identity and purity. The 12-week experiment resulted in significant alteration of the mineral substrates. SEM, EDX, and XRD analysis showed secondary mineral biomineralization represented by different crystal morphologies of Ca- and Mg- oxalates (weddelite: CaC2O4·2H2O, whewellite CaC2O4·H2O and glushinskite: MgC2O4·2H2O), struvite: (NH4) MgPO4·6H2O, gypsum CaSO4.2H2O, and possible dolomite. Metals bioleached from the substrates included: Fe, Pb, S, Cu, Al as single crystals or aggregates, amorphous layers, amorphous aggregates, and linear forms influenced by the fungal filaments. Bauxite and manganite showed the strongest cases of bioleaching where Fe and Al were fungally extracted and deposited as separate mineral species from the Al-Fe oxides mixture, while Ca and S were extracted from the manganite substrate and deposited as gypsum. The bioleached metals were either deposited on the mineral substrates, attached to fungal filaments, embedded in the fungal mycelium or in the extracellular polysaccharide substance (EPS) layer. The EDX microanalysis of the fungal hyphae frequently revealed metal content adsorbed on the hyphae sheath surface. During the short period of the experiment, fungal interaction with the mineral surfaces produced significant biomechanical and biochemical bioweathering features: strong pitting of the mineral surfaces, exfoliation, tunnelling, dissolution, honeycomb-alveolar structures, perforations, fragmentation, and cementation. One important aspect of these interactions is the strong affinity of fungal hyphae to mineral surfaces. The fungi engulfed whole blocks of minerals in the hyphal network, irrespective of mineral surface topography with

  19. Biomass gasification and in-bed contaminants removal: performance of iron enriched olivine and bauxite in a process of steam/O2 gasification.

    Science.gov (United States)

    Barisano, D; Freda, C; Nanna, F; Fanelli, E; Villone, A

    2012-08-01

    A modified Olivine, enriched in iron content (10% Fe/Olivine), and a natural bauxite, were tested in the in-bed reduction of tar and alkali halides (NaCl and KCl) released in a process of biomass steam/O(2) gasification. The tests were carried out at an ICBFB bench scale reactor under the operating conditions of: 855-890 °C, atmospheric pressure, 0.5 steam/biomass and 0.33 ER ratios. From the use of the two materials, a reduction in the contaminant contents of the fuel gas produced was found. For the alkali halides, a decrease up to 70%(wt) was observed for the potassium concentration, while for sodium, the reduction was found to be quite poor. For the organic content, compared to unmodified Olivine, the chromatographically determined total tar quantity showed a removal efficiency of 38%(wt). Moreover, regarding the particulate content a rough doubling in the fuel gas revealed a certain brittleness of the new bed material.

  20. Micro-structural characterization of the hydration products of bauxite-calcination-method red mud-coal gangue based cementitious materials.

    Science.gov (United States)

    Liu, Xiaoming; Zhang, Na; Yao, Yuan; Sun, Henghu; Feng, Huan

    2013-11-15

    In this research, the micro-structural characterization of the hydration products of red mud-coal gangue based cementitious materials has been investigated through SEM-EDS, (27)Al MAS NMR and (29)Si MAS NMR techniques, in which the used red mud was derived from the bauxite calcination method. The results show that the red mud-coal gangue based cementitious materials mainly form fibrous C-A-S-H gel, needle-shaped/rod-like AFt in the early hydration period. With increasing of the hydration period, densification of the pastes were promoted resulting in the development of strength. EDS analysis shows that with the Ca/Si of red mud-coal gangue based cementitious materials increases, the average Ca/Si and Ca/(Si+Al) atomic ratio of C-A-S-H gel increases, while the average Al/Si atomic ratio of C-A-S-H gel decreases. MAS NMR analysis reveals that Al in the hydration products of red mud-coal gangue based cementitious materials exists in the forms of Al(IV) and Al(VI), but mainly in the form of Al(VI). Increasing the Ca/Si ratio of raw material promotes the conversion of [AlO4] to [AlO6] and inhibits the combination between [AlO4] and [SiO4] to form C-A-S-H gel. Meanwhile, the polymerization degree of [SiO4] in the hydration products declines.

  1. Leaching of copper and nickel in soil-water systems contaminated by bauxite residue (red mud) from Ajka, Hungary: the importance of soil organic matter.

    Science.gov (United States)

    Lockwood, Cindy L; Stewart, Douglas I; Mortimer, Robert J G; Mayes, William M; Jarvis, Adam P; Gruiz, Katalin; Burke, Ian T

    2015-07-01

    Red mud is a highly alkaline (pH >12) waste product from bauxite ore processing. The red mud spill at Ajka, Hungary, in 2010 released 1 million m(3) of caustic red mud into the surrounding area with devastating results. Aerobic and anaerobic batch experiments and solid phase extraction techniques were used to assess the impact of red mud addition on the mobility of Cu and Ni in soils from near the Ajka spill site. Red mud addition increases aqueous dissolved organic carbon (DOC) concentrations due to soil alkalisation, and this led to increased mobility of Cu and Ni complexed to organic matter. With Ajka soils, more Cu was mobilised by contact with red mud than Ni, despite a higher overall Ni concentration in the solid phase. This is most probably because Cu has a higher affinity to form complexes with organic matter than Ni. In aerobic experiments, contact with the atmosphere reduced soil pH via carbonation reactions, and this reduced organic matter dissolution and thereby lowered Cu/Ni mobility. These data show that the mixing of red mud into organic rich soils is an area of concern, as there is a potential to mobilise Cu and Ni as organically bound complexes, via soil alkalisation. This could be especially problematic in locations where anaerobic conditions can prevail, such as wetland areas contaminated by the spill.

  2. 广西那坡县龙合矿区铝土矿地质特征%Geological characteristics of bauxite deposits in Longhe mining area of Napo in Guangxi

    Institute of Scientific and Technical Information of China (English)

    覃全光

    2015-01-01

    A large-scale accumulation type bauxite deposit was found through prospecting and exploration in Longhe mining area in Napo of Guangxi,and this deposit played the role of backup resource base in the de-velopment of aluminum industry in Guangxi.The accumulation type bauxite deposit occurred in karst accu-mulation laterite formation of Pleistocene Epoch inside karst depression and it was formed in Pleistocene Ep-och under the primary mineralizing processes of karstification and lateritization with fossil weathering crust type bauxite ore beds (rock strata)of Permian lower Heshan Formation as its ore-forming material source. The mineralization and enrichment were mainly controlled by factors such as ore source bed,formation li-thology,tectonic movement,climate and landform.%通过找矿勘探,在那坡县龙合矿区发现一处大型规模的堆积铝土矿矿床,为广西区铝工业发展提供后备资源基地。堆积铝土矿赋存于岩溶洼地内更新世岩溶堆积红土层中,成矿物质来源于上二叠统合山组底部的古风化壳型铝土矿(岩)层,主要成矿时代为更新世,主导成矿作用为岩溶作用、红土化作用。矿化富集主要受矿源层、地层岩性、构造运动、气候和地貌等因素控制。

  3. 露天采矿机在红土型铝土矿的开采工艺研究%Research on Mining Technology of Surface Miner in Lateritic Bauxite

    Institute of Scientific and Technical Information of China (English)

    陈振超

    2013-01-01

    Lateritic bauxite has the characteristics of large deposit reserves and large area and easy for open pit mining on a large scale, but upper gossan of ore bed is too hard and lower laterite is soft, therefore, traditional mining technologies of drilling and blasting are not applicable. By combination of engineering example of lateritic bauxite in Guinea, the paper investigates the feasibility of lateritic bauxite mining by using surface miner, and compares development and transportation schemes of this kind of deposit. The research shows that it is feasible in technology by selection of surface miner as stripping machine and application of combination transportation of truck and belt, and it can reach better benefit in economy.%红土型铝土矿具有矿床储量大、平面面积大的特点,易于大规模露天开采,但矿层上部铁帽较硬,下部红土较软,不适应传统的穿孔、爆破采矿工艺。结合几内亚某红土型铝土矿的工程实例,研究了采用露天采矿机开采红土型铝土矿的可行性,并对此类型矿床的开拓运输方案进行了比较。研究表明,选用露天采矿机作为采剥设备,配合汽车+胶带联合运输,在技术上是可行的,经济上也能达到较好的效果。

  4. Micro-structural characterization of the hydration products of bauxite-calcination-method red mud-coal gangue based cementitious materials

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaoming [State Key Laboratory of Advanced Metallurgy, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Na [Green Construction Materials and Circulation Economy Center, Architectural Design and Research Institute of Tsinghua University Co., Ltd., Beijing 100084 (China); Yao, Yuan, E-mail: yuanyaocas@163.com [School of Engineering and Computer Science, University of the Pacific, Stockton, CA 95211 (United States); Sun, Henghu; Feng, Huan [School of Engineering and Computer Science, University of the Pacific, Stockton, CA 95211 (United States)

    2013-11-15

    Highlights: • Al{sup IV} and Al{sup VI} both exist in the hydration products. • Increase of Ca/Si ratio promotes the conversion from [AlO{sub 4}] to [AlO{sub 6}]. • Polymerization degree of [SiO{sub 4}] in the hydration products declines. -- Abstract: In this research, the micro-structural characterization of the hydration products of red mud-coal gangue based cementitious materials has been investigated through SEM-EDS, {sup 27}Al MAS NMR and {sup 29}Si MAS NMR techniques, in which the used red mud was derived from the bauxite calcination method. The results show that the red mud-coal gangue based cementitious materials mainly form fibrous C-A-S-H gel, needle-shaped/rod-like AFt in the early hydration period. With increasing of the hydration period, densification of the pastes were promoted resulting in the development of strength. EDS analysis shows that with the Ca/Si of red mud-coal gangue based cementitious materials increases, the average Ca/Si and Ca/(Si + Al) atomic ratio of C-A-S-H gel increases, while the average Al/Si atomic ratio of C-A-S-H gel decreases. MAS NMR analysis reveals that Al in the hydration products of red mud-coal gangue based cementitious materials exists in the forms of Al{sup IV} and Al{sup VI}, but mainly in the form of Al{sup VI}. Increasing the Ca/Si ratio of raw material promotes the conversion of [AlO{sub 4}] to [AlO{sub 6}] and inhibits the combination between [AlO{sub 4}] and [SiO{sub 4}] to form C-A-S-H gel. Meanwhile, the polymerization degree of [SiO{sub 4}] in the hydration products declines.

  5. Development of sintering-resistant CaO-based sorbent derived from eggshells and bauxite tailings for cyclic CO2 capture.

    Science.gov (United States)

    Shan, ShaoYun; Ma, AiHua; Hu, YiCheng; Jia, QingMing; Wang, YaMing; Peng, JinHui

    2016-01-01

    Carbon dioxide, one of the major greenhouse gases, are believed to be a major contributor to global warming. As a consequence, it is imperative for us to control and remove CO2 emissions. The CaO, a kind of effective CO2 sorbent at high temperature, has attracted increasing attention due to some potential advantages. The main drawback in practical application is the deterioration of CO2 capture capacity following multiples cycles. In the present study, novel low-cost porous CaO-based sorbents with excellent CO2 absorption-desorption performance were synthesized using bauxite tailings (BTs) and eggshells as raw materials via solid-phase method. Effect of different BTs content on CO2 absorption-desorption properties was investigated. Phase composition and morphologies were analyzed by XRD and SEM, and CO2 absorption properties were investigated by the simultaneous thermogravimetric analyzer. The as-prepared CaO-based sorbent doped with 10 wt% BTs showed superior CO2 absorption stability during multiple absorption-desorption cycles, with being >55% conversion after 40 cycles. This improved CO2 absorption performance was attributed to the particular morphologies of the CaO-based sorbents. Additionally, during absorption-desorption cycles the occurrence of Ca12Al14O33 phase is considered to be responsible for the excellent CO2 absorption performance of CaO-based sorbents. In the meanwhile, the use of solid waste eggshell and BTs not only decreases the release of solid waste, but also moderates the greenhouse effect resulted from CO2.

  6. The stabilities of gibbsite, boehmite, aluminous goethites and aluminous hematites in bauxites, ferricretes and laterites as a function of water activity, temperature and particle size

    Science.gov (United States)

    Trolard, Fabienne; Tardy, Yves

    1987-04-01

    Stability relationships between Al-goethite, Al-hematite, boehmite and gibbsite are presented in terms of water activity [H 2O], temperature ( T), grain size and bulk-composition in the system Fe 2O 3-Al 2O 3-H 2O at a total pressure of 1 bar. Al-goethite and Al-hematite are treated as ideal solid solutions, the former of the end-members FeOOH (goethite) and AlOOH (diaspore) and the latter of the end-members Fe 2O 3 (hematite) and Al 2O 3 (corundum). Using log K sp provided by the literature for the various phases involved, the common associations observed in laterites, bauxites and ferricretes do not have stability fields over geologically reasonable intervals of [H 2O] and T. Consequently a new internally consistent set of log Ksp values is proposed and used, and allows such associations to have actual stability fields in the appropriate diagrams. The new log Ksp values used in the calculations are such that the solubilities of the end members are greater than those commonly listed. This is in agreement with natural observations which show that such minerals, are generally poorly crystallized and of very small size. The assumption of an ideal solid solution in aluminous goethite and aluminous hematite combined with the new log Ksp values leads to prediction of composition limits for these two minerals which agree well with observed values. The fact that an ideal solid solution must extend continuously from one end-member to the other is masked by the appearance of other stability fields ( e.g. gibbsite or boehmite) which cross and overlap a part of the solid solution stability fields of AlOOH-FeOOH and Fe 2O 3-Al 2O 3.

  7. 渝南水江板桥铝土矿区锂的分布规律及其影响因素研究%Distribution law of Lithium and its influencing factors in Shuijiangbanqiao bauxite mining area, Southern Chongqing

    Institute of Scientific and Technical Information of China (English)

    邓国仕; 李军敏; 杨桂花; 赵晓东; 陈莉; 陈阳; 吕涛

    2014-01-01

    Based on the study of the bauxite and Scandium of Shuijiangbanqiao mine in Southern Chongqing ,the Al2 O3 was found distribute mainly in the upper and middle-upper layers ,the main type of bauxite are pisolitic ,olitic structures and massive structures .The Lithium was found distributed mainly in the upper and middle-upper layers ,the main type of bauxite is massive bauxite .Lithium is changing from 200 to 1400 × 10-6 and average in 830 .23 × 10-6 .The content of Lithium which is higher in Aluminum clay than in bauxite .The average of correlation coefficient r=0 .820 between Lithium and Al2 O3 ,it is a severe plus correlation .The average of correlation coefficient r= -0 .653 between Lithium and SiO2 ,it is a moderate negative correlation .The average of correlation coefficient r=0 .885 between Lithium and A/S ,it is a severe plus correlation .The seam of Li was affected by horizons ,the impact of ore types ,southern Chingqing , China .%通过对渝南水江板桥铝土矿区五个典型探槽中铝土矿(岩)和稀散元素锂的研究,发现Al2 O3主要分布在含矿层位的上部和中上部,其矿石类型主要为豆(鲕)状和砾屑状,锂主要分布在含矿层位的上部和中上部,主要赋存的岩石类型为砾屑状高铝黏土岩。Li含量在200~1400×10-6之间,平均含量为830.23×10-6;Li在铝土矿含矿岩系上部和中上部的高铝黏土岩中最为富集;铝土矿矿石中Li含量较高,平均为531.37×10-6。Li与Al2 O3相关系数平均值 r=0.820,为正的强相关;Li与SiO2相关系数平均值r=-0.653,为负的中等相关;Li与A/S比值的相关系数平均值 r=0.885,为正的强相关。在渝南铝土矿含矿岩系中,Li矿层的形成受层位、矿石类型的影响。

  8. Stabilities of gibbsite, boehmite, aluminous goethites and aluminous hematites in bauxites, ferricretes and laterites as a function of water activity, temperature and particle size

    Energy Technology Data Exchange (ETDEWEB)

    Trolard, F.; Tardy, Y.

    1987-04-01

    Stability relationships between Al-goethite, Al-hematite, boehmite and gibbsite are presented in terms of water activity (H/sub 2/O), temperature (T), grain size and bulk-composition in the system Fe/sub 2/O/sub 3/-Al/sub 2/O/sub 3/-H/sub 2/O at a total pressure of 1 bar. Al-goethite and Al-hematite are treated as ideal solid solutions, the former of the end-members FeOOH and AlOOH and the latter of the end-members Fe/sub 2/O/sub 3/ (hematite) and Al/sub 2/O/sub 3/ (corundum). Using log K/sub sp/ provided by the literature for the various phases involved, the common associations observed in laterites, bauxites and ferricretes do not have stability fields over geologically reasonable intervals of (H/sub 2/O) and T. Consequently a new internally consistent set of log K/sub sp/ values is proposed and used, and allows such associations to have actual stability fields in the appropriate diagrams. The new log K/sub sp/ values used in the calculations are such that the solubilities of the end members are greater than those commonly listed. This is in agreement with natural observations which show that such minerals, are generally poorly crystallized and of very small size. The assumption of an ideal solid solution in aluminous goethite and aluminous hematite combined with the new log K/sub sp/ values leads to prediction of composition limits for these two minerals which agree well with observed values. The fact than an ideal solid solution must extend continuously from one end-member to the other is masked by the appearance of other stability fields which cross and overlap a part of the solid solution stability fields of AlOOH-FeOOH and Fe/sub 2/O/sub 3/-Al/sub 2/O/sub 3/.

  9. 山西某露天铝土矿投资开发思路浅析%The investment and development conception analyses for a open-cast bauxite mine in Shanxi province

    Institute of Scientific and Technical Information of China (English)

    杨同海

    2014-01-01

    According to a open-cast bauxite mine investment and development practice in Shanxi Province, the risk analysis is carried out from five aspects of investment and development subject, development model, land requisition, size of mining, the mine ecological environment protection, puts forward corresponding measures and suggestions are proposed, so as to provide reference for similar mining investment.%结合山西某露天铝土矿投资开发实际,从投资开发主体、开发模式、土地征用、开采规模、矿山生态环境保护五个方面进行了风险分析,提出了相应的处理措施和建议,为类似矿业投资提供一定的参考。

  10. Variation of biometric parameters and C, N, and P concentrations of Oryza glumaepatula at different depths of an Amazonian lake impacted by bauxite tailings (Lake Batata, Pará, Brazil).

    Science.gov (United States)

    Enrich-Prast, A; Esteves, F A; Breves, A R

    2002-02-01

    Lake Batata is a typical Amazonian clear water lake which has undergone anthropogenic impacts. Thirty percent of its total area has been covered with bauxite tailings. Thus, it is possible to distinguish two areas in this ecosystem: the impacted and the natural. The goal of this research was to study C, N, and P content variation and the values of biomass, length, density, and culm diameter of Oryza glumaepatula at different depths in the natural and impacted areas of Lake Batata. The results obtained in this research suggest that the availability of P and N, in both water and sediment, is lower at the shallow site when compared to the deeper sites. On the other hand, C concentrations decreased as P and N concentrations increased. This may be explained by the structural function of C in aquatic macrophytes. At shallower sites, due to the reduced water column, individuals invest in supporting structures that display high C concentrations. The higher density and biomass of O. glumaepatula at the intermediate site indicate that this area presents the best conditions for germination and establishment of individuals of this species. The chemical composition and biometric parameters of O. glumaepatula have shown that this population has higher spatial variation in the natural area. In the impacted area, the absence of significant variations in N and P concentrations in O. glumaepatula among the three sampled sites promotes higher homogeneity in the stands. The high C:P and N:P ratios indicate that, in the impacted area, P is more limiting to the development of O. glumaepatula than it is in the natural area. The reduced values of biomass and density of O. glumaepatula in the impacted area suggest that the bauxite tailings limit the development of this population.

  11. 利用微泡浮选柱分选中低品位铝土矿的试验研究%Beneficiation of Middle-low Grade Bauxite with Micro-bubble Flotation Column

    Institute of Scientific and Technical Information of China (English)

    欧乐明; 王立军; 冯其明; 万丽; 叶家笋

    2011-01-01

    在研究矿石性质的基础上,利用新型微泡浮选柱对河南某中低铝硅比铝土矿进行了实验室分选研究,考察了捕收剂、抑制剂、充气量和淋洗水对分选结果的影响.闭路试验结果表明,在优化条件下,采用新型微泡浮选柱可得到精矿铝硅比为10.26,氧化铝回收率87.24%的实验指标.试验证明新型微泡浮选柱对细粒铝土矿分选有良好的应用前景.%Based on the analysis of mineral properties, a new type of micro-bubble flotation column was used in a laboratory study on beneficiation of a middle-low grade bauxite from Henan Province. The influence of collector, depressant, aeration rate and eluent flow rate on the separation effect was investigated. The results of the close-circuit test show that, under the optimized conditions, the A/S ratio for the concentrate can be enhanced to 10.26 and the aluminum recovery can be increased to 87. 24% , which testifies that this new type of micro-bubble flotation column may have promising application potential in bauxite separation.

  12. 细菌-矿物接触方式对铝土矿降解的影响%Influence of microbe-mineral contact model on decomposition of bauxite

    Institute of Scientific and Technical Information of China (English)

    孙德四; 陈晔; 曹飞

    2013-01-01

    Microorganisms can promote the degradation of alumino-silicates by direct and indi-rect mechanisms. But the contribution of both mechanisms to the mineral degradation is still in controversy. The microfiltration membrane was used to segregate the mineral from bacteria. The effects of silicate bacteria on degradation and desilicon of bauxite were studied by the static and dynamical culture. The results show that the microbe-mineral dynamic contact model is more beneficial to promote the bacteria growth and form the mycelium-mineral complex. The biomass and the mineral powder quantity absorbed by bacteria under the dynamical culture are 1. 55 and 2. 19 times that under the static culture, respectively. The SiO2 concentrations of the bioleaching supernatant are 2. 96 and 2. 22 times that under the static contact and dynamic un-contact models, respectively. The microbe-mineral contact model is more conductive to the deg-radation of bauxite than the microbe-mineral uncontact model under the dynamic culture. The silicate bacteria can degrade bauxite in the mechanical breakage of the mycelium, the corrosion and complexion of metabolites and the integrated operation of many factors.%微生物可通过直接与间接作用方式影响铝硅酸盐矿物的降解,但这两种方式的贡献有所差异.利用微孔滤膜将细菌与矿粉隔离,通过静态与动态培养,研究硅酸盐细菌对铝土矿降解溶硅的影响.结果表明:在细菌-矿物直接作用模式下,动态培养更有利于促进细菌生长与细菌-矿物复合体的形成,培养基中的生物量与细菌吸附的矿粉量分别是静态培养条件下的1.55和2.19倍;其浸矿培养基上清液中的SiO2的含量分别是直接静态培养与间接动态培养的2.96和2.22倍.比较细菌-矿物直接作用与间接作用模式,直接接触模式比间接接触模式对铝土矿的降解脱硅作用更显著,硅酸盐细菌对铝土矿的降解作用包括机械破坏、代谢产物溶蚀

  13. A geopolimerização como técnica para a aplicação do resíduo de bauxita Geopolymerization as a technique for bauxite residue applications

    Directory of Open Access Journals (Sweden)

    C. S. Bitencourt

    2012-03-01

    Full Text Available Encontrar aplicações sustentáveis para o resíduo de bauxita tem se mostrado um dos principais desafios da indústria do alumínio na atualidade. Com esse propósito, a geopolimerização pode se tornar uma solução interessante, uma vez que essa técnica seria capaz de tirar proveito de algumas das características mais típicas desse resíduo, como sua elevada alcalinidade e o seu significativo teor de compostos de silício e alumínio, produzindo materiais sólidos semelhantes em propriedades às cerâmicas tradicionais. Neste trabalho, o processamento, as propriedades e as possíveis aplicações dos geopolímeros compostos por resíduo de bauxita foram analisados. Além dos ensaios de porosidade aparente e resistência mecânica, as amostras preparadas também foram submetidas a um ensaio de lixiviação, de modo a já realizar uma avaliação prévia dos potenciais riscos ambientais decorrentes da utilização de um possível produto, e de quais procedimentos favoreceriam a sua passivação. Entre os principais resultados obtidos, verificou-se que a queima a 800 °C permitiu a algumas das composições desenvolvidas alcançarem valores de resistência à compressão da ordem de até 30 MPa, além de uma resistência à lixiviação muito próxima à de um tijolo de argila prensado comum, o que já permite considerar a construção civil como um dos setores mais favoráveis para a aplicação dos geopolímeros com resíduo de bauxita, principalmente pela enorme capacidade de consumo desse setor e da sua crescente demanda por produtos mais sustentáveis.Finding sustainable applications for the bauxite residue is one of the leading challenges in the aluminium industry. For this purpose, the geopolymerization could become an interesting alternative, because this technique could make use of some of the typical characteristics of the bauxite residue, such as its alkalinity and expressive silicates and aluminates contents, resulting in solid

  14. 利用 PGNAA 系统对铝土矿石进行在线检测的可行性研究%Feasibility study for on-line analysis of bauxite using a PGNAA system

    Institute of Scientific and Technical Information of China (English)

    宋青锋; 龚亚林; 张伟; 赵龙; 尚庆敏; 谢福生

    2015-01-01

    利用一款基于瞬发γ中子活化原理设计的主要针对皮带散状物料元素进行在线检测的工业仪器,研究这款仪器用于测量铝土矿组成分析的可行性,实验主要进行了两组样品中 Ca、Si、Al、Fe、Ti 五种元素的测试,其中一组样品由高纯氧化物组成,一组样品由铝土矿和高纯氧化物组成,测量结果表明, CaO、SiO2、Al2 O3、Fe2 O3、TiO2的测量精度分别为±0.23%、±0.18%、±0.35%、±0.14%、±0.08%,能够满足原料自动配比及入厂原料质量控制的要求。%An industrial prompt-gamma neutron activation analysis(PGNAA)system,designed for the real-time elemental analysis of bulk materiel on a conveyor belt,has been studied to examine the feasibility of using such a system for bauxite composition analysis.Experiments were conducted to measure Ca Si Fe Al in two simple,one simple is comprised of pure oxide,and the other simple is comprised of bauxite and pure oxide.The static accuracy are ± 0.23% (CaO),± 0.18% (SiO2 ),± 0.35% (Al2 O3 ),± 0.14% (Fe2 O3 ), ±0.08%(TiO2 ).The instrument can meet the requirements of automatic mixing system of row material and quality controlling after entering factory.

  15. Towards an impact assessment of bauxite red mud waste on the knowledge of the structure and functions of bathyal ecosystems: The example of the Cassidaigne canyon (north-western Mediterranean Sea).

    Science.gov (United States)

    Dauvin, Jean-Claude

    2010-02-01

    Since 1967, the alumina plants in the Marseilles area (Barasse and Gardanne) have been discharging the mineral residue (i.e., red mud) resulting from the alkaline processing of bauxite into the submarine Cassidaigne canyon (north-western Mediterranean Sea) through pipes situated at 320-330 m in depth. The Barasse pipe stopped being used in 1988. From 1987 to 1996, many decrees and regulations were promulgated by the French State to rule the conditions under which the Gardanne alumina refinery was authorized to dispose of the bauxite residue in the sea. The refinery was required: (i) to study the hydrodynamic circulation in the Cassidaigne canyon to evaluate the potential dispersion and transport of fine elements discharged into the water mass and their impact on the pelagic ecosystem; (ii) to survey the marine environment every five years to control the expansion and thickness of the red mud deposit and compare the evolution of the benthic macrofauna at representative sampling sites in the environment affected by the red mud discharge with that of reference sites outside of the red mud plume; (iii) to study the effect of the discharge on fishing activities; and (iv) to investigate the toxicity of the red mud, particularly its persistence, accumulation, interaction and effect on the marine ecosystem, paying special attention to the bio-accumulation of chromium and vanadium. A Scientific Committee was created to insure an independent evaluation of the studies promised by the manufacturer in response to the State's regulations. Since the beginning of the 1960s, data have been accumulating on the structure and long-term functioning of the Cassidaigne bathyal ecosystem. This paper presents the collaborative efforts of the State-Manufacturer-Committee triplet and summarizes the main results obtained during the last period's sea campaigns (1991-2007). This paper also illustrates how national regulations concerning manufacturers, such as Gardanne alumina refinery, have

  16. PDC钻头双管钻探工艺在河南西部铝土矿地层的应用%Application of PDC bit and double tube swivel drilling techniques in west of Henan bauxite strata

    Institute of Scientific and Technical Information of China (English)

    潘广灿; 张金来

    2011-01-01

    文章分析探讨铝土矿地层钻探工艺,采用常规绳索取芯钻探、普通双管钻探与PDC双管钻探对比进行,钻进中采用常规钻探方法常发生钻具粘附孔壁而产生的卡钻问题,致使钻探效率低,采用PDC钻头双管钻探不仅较好地解决了粘附孔壁而卡钻的问题,而且提高了钻探效率.%In the paper the authors analyzed and discussed the drilling technology in bauxite strata, through the comparation of conventional rope core drilling, normal twin pipe drilling and drilling PDC double. Conventional drilling method could not solve drill hole wall adhesion and sticking problems, often making drilling with low efficiency. While PDC bits and double pipe drilling can better solve the adhesion of the hole wall and the sticking of problems, improving drilling efficiency.

  17. Estudo da ativação ácida e tratamento térmico de bauxita extraída de jazidas em Minas Gerais, Brasil Study of acid activation and thermal treatment of bauxite extracted from deposits in Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    C. M. R. Prado

    2012-03-01

    Full Text Available O Brasil é um dos maiores produtores mundiais de bauxita, contudo pouco se conhece sobre as características químicas e mineralógicas desse mineral. Assim sendo, este trabalho tem por objetivo dar prosseguimento à caracterização de bauxita, estudando as transformações ocorridas nesse material quando submetido à ativação ácida e ao tratamento térmico. Os resultados demonstraram que a bauxita "in natura" é composta basicamente pelo mineral gibbsita, seguido de semicristalitos de goethita e óxido de silício, apresentando característica de sólido com ausência de mesoporosidade, com baixos valores de área superficial total, diâmetro e volume de poros. As modificações químicas e físicas que ocorrem no material durante a calcinação são governadas, principalmente, pela desidratação das fases de hidróxidos de alumínio presentes, levando à formação das fases boehmita, hematita e alfa alumina, além de resultar em aumento na porosidade e na área superficial da bauxita. As bauxitas ativadas em meio ácido mostraram que as transformações sofridas no sólido estão diretamente relacionadas com a concentração da solução ácida utilizada e resultam em aumento da área superficial total, diâmetro e volume de poros.Brazil is one of the world's leading producers of bauxite. Little is known, however, about the chemical and mineralogical characteristics of Brazilian bauxite. The objective of this paper is to characterize bauxite in both natural and thermally and chemically activated forms. The transformations occurring during these two processes are described. The results show that the raw bauxite is basically composed of the mineral gibbsite, followed by semicrystalites of goethite and silicon oxide. Its characteristics are those of a solid without mesoporosity, with small total surface area and pore diameter and volume. The chemical and physical modifications that occur in the material during the calcination process are

  18. EFFECTS OF THE USE OF BAUXITE MINING RESIDUES ON MICRONUTRIENT AND SODIUM LEVELS IN SUGARCANE = EFEITO DO USO DE RESÍDUO DO PROCESSAMENTO DE BAUXITA NOS TEORES DE MICRONUTRIENTES E SÓDIO EM PLANTAS DE CANA-DE-AÇÚCAR

    Directory of Open Access Journals (Sweden)

    Reginaldo Itiro Muraishi

    2008-01-01

    Full Text Available Population growth and the consequent demand for consumer goods as well as the increase in industrial development generates great amounts of residues. The aluminum extraction industry pruduces mainly residues from the industrial processing of bauxite, in amounts correlated with the industry size and they are disposed of in large containment lakes, causing significant environmental impact. Thus, the objective of the present study was to verify, in a protected environment, the effect of the addition of bauxite residues on sugarcane plants (SP92 4221, in relation to micronutrient levels in the plant. The following levels of bauxite processing residues were added to 10 litres containers: 0, 2, 4, 6, 8 and 10% of the volume of the containers, corresponding to 0, 28, 56, 84, 112 and 140 t ha-1. Results indicate that application of bauxite mining residues increased the levels of Mn and Na in the plants and decreased Zn, Cu and Fe absorption, and that higher levels of the residue inhibited the development of the crop. = O crescimento populacional, a demanda por bens de consumo e, conseqüentemente o aumento do desenvolvimento industrial produz quantidades expressivas de resíduos. A indústria de extração de alumínio gera principalmente resíduos provenientes do processamento industrial da bauxita, em quantidades que se correlacionam diretamente com o porte industrial. Esse descarte é depositado em grandes lagos de contenção, causando forte impacto ambiental. Assim, o objetivo do presente trabalho foi verificar, em ambiente protegido, o efeito da adição do resíduo de processamento de bauxita em plantas de cana-de-açúcar (SP92 4221, em relação aos teores de micronutrientes na planta. Foram utilizados vasos de 10 litros que receberam as seguintes doses de resíduo da mineração de bauxita: 0, 2, 4, 6, 8 e 10% do volume dos vasos, correspondendo respectivamente a, 0, 28, 56, 84, 112 e 140 t ha-1. Os resultados obtidos evidenciaram que a aplica

  19. Utilization of Phosphogypsum and Low Grade Bauxite for Belite Rich Calcium Sulphoaluminate Cement%磷石膏与低品位矾土制备高贝利特-硫铝酸盐水泥

    Institute of Scientific and Technical Information of China (English)

    梁娇; 刘娜; 刘从振; 郭清春; 李昕成; 钱觉时

    2016-01-01

    利用磷石膏和低品位矾土制备高贝利特-硫铝酸盐水泥,研究了熟料的最佳煅烧工艺制度及配入过量磷石膏对水泥性能的影响。结果表明:在1300℃保温0.5 h,烧制出性能良好的高贝利特-硫铝酸盐水泥熟料,3 d和28 d水泥净浆抗压强度分别可达54.1 MPa和59.1 MPa;过量磷石膏形成的高温硬石膏能起到后掺石膏的作用,对水泥早期力学性能无不利影响。%Belite rich calcium sulphoaluminate cement was prepared with phosphogypsum and low grade bauxite. The optimum burning process for the clinker production and the excessive amount of phosphogypsum in the clinker on the performance of the cement were investigated. The results demonstrate that belite rich calcium sulphoaluminate cement with excellent performances can be achieved. The compressive strength of the cement paste at 3 d and 28 d reaches 54.1 MPa and 59.1 MPa, separately. The excessive amount of phosphgypsum in the clinker turns into anhydrate, serving the added gypsum and satisfying the hydration of C4A3S—. And the anhydrate does not harm the strength development of the cement paste.

  20. Sodium nitrite induced mutagenesis of bacteria and bioleaching silicon from bauxite%细菌亚硝酸钠诱变育种及铝土矿浸矿脱硅

    Institute of Scientific and Technical Information of China (English)

    钟婵娟; 孙德四; 王化军; 张强

    2013-01-01

    The original strains, Bacillus mucilaginosus CGMCC11 and Bacillus circulans CGMCC12, were treated by sodium nitrite to induce mutagenesis and investigate bioleaching of bauxite. The results show that the optimum temperature and pH value are 28℃and 7.2 for B∙M CGMCC11, and 30℃and 8.3 for B∙C CGMCC12. The lethal rates of B∙M CGMCC11 and B∙C CGMCC12 are 87% and 85%, and the positive mutant rates are 18%and 20%after being treated by 40 and 60 mg/L sodium nitrite culturing, respectively. The two mutants, B∙M CGMCC11KP and B∙C CGMCC12KP, screened from positive mutant strains reach stationary stages by 48 and 24 h ahead of the corresponding original strains, and have higher bacterial concentrations and higher ability of producing organic acids and macromolecule extracellular polymers than the original strains. After leaching for 15 d, the SiO2 concentrations in supernatants of the mutant stains of B∙M CGMCC11KP and B∙C CGMCC12KP are improved by 30.47% and 29.57%, and the leaching time of 5 and 3 d shorter, respectively, than those of the two corresponding original strains. After bioleaching with the mixture of B∙M CGMCC11KP and B∙C CGMCC12KP, the SiO2 concentration of the supernatant is 20.0%and 37.5%higher than those of the corresponding mutants, and the mixture can shorten the leaching time by 6 d in comparison with the original strains. The SEM and XRD analyses of bauxite surfaces before and after leaching show that the mixture of B∙M CGMCC11KP and B∙C CGMCC12KP has the greatest corrosion and decomposition ability on bauxite. After bioleaching for 15 d, the proportion of cell density in the supernatants of B∙M CGMCC11 and B∙C CGMCC12 is changed from 1:1 to approximately 10:1.%  以胶质芽孢杆菌CGMCC11和环状芽孢杆菌CGMCC12为出发菌株,采用亚硝酸钠对其进行诱变育种与浸矿研究。结果表明:菌株CGMCC11和CGMCC12的最适生长温度分别为28和30℃,最适pH值分别为7.2和8.3。采用40和60

  1. Influence of particle size composition on self-flowability of bauxite-silicon carbide shotcreting castables%粒度组成对高铝-碳化硅质湿式喷射料自流性的影响

    Institute of Scientific and Technical Information of China (English)

    姚金甫; 田守信; 王峰

    2011-01-01

    Bauxite-silicon carbide shotcreting castables was prepared with starting materials of sintered mullite,silicon carbide,alumina micropowder, silica fume, and binder of ultra-low cement. Influence of particle size composition on self-flowability of shotcreting castables was researched. The results show that: ( 1 ) shotcreting castables has good self-flowability and properties with 20% fine grain ≤ 1 mm;(2)self-flow castables has enough powder to get good self-flowability when powder content is 38%-41% and q value of Andreassen equation is 0.23-0.25; (3) powders with craggedness hillside contribution can give the castables good self-flowability and reasonable micropowder combination which result in a good bonding between particles and matrix,improving the pumping properties of castables.%以烧结莫来石M70(骨料和粉料)、碳化硅粉、氧化铝微粉、硅微粉、棕刚玉微粉等为原料,采用超低水泥结合体系,制备了高铝-碳化硅质湿式喷射料,研究了粒度组成对湿式喷射料自流性的影响.结果表明:≤1mm的细颗粒含量(w)为20%时,喷射料的自流性和性能较好;细粉含量(w)为38%~41%,Andreassen方程中q值在0.23~0.25之间时,能够确保自流料有足够的细粉以获得良好的自流性;采用山坡陡峭型粒度分布的一般细粉可使喷射料具有良好的自流性,合理的微粉组合可使颗粒和基质之间具有较好的结合性,有利于改善喷射料的泵送性能.

  2. Orientation Screening and Desilicon Abilities of Silicon-releasing Microorganisms from Bauxite%铝土矿脱硅微生物的定向筛选及脱硅性能

    Institute of Scientific and Technical Information of China (English)

    钟婵娟; 肖国光; 曹飞; 孙德四

    2013-01-01

    from minerals than other strains in the culture media, and can form obviously bacteria-mineral complexes. Strains P04 and P17 belonged to Bacillus circullans in comparison of their characteristics with those of the modal strain. Strains P04, P17 and P19 can decompose silicate minerals in bauxite and release silicon from them. The maximum concentrations of SiO2 of supernatants in the media are 49.69, 32.78, 37.98 mg/L, respectively after bioleaching for 12 days, and the ratios of Al2O3 to SiO2(A/S) of bauxite increased from 5.17 to 10.99, 7.61,8.90 respectively. It is concluded that the silicate bacterium with higher abilities of producing acids and polysaccharides and forming obviously bacteria-mineral complexes has higher desilicon abilitiy.

  3. 不同粒度的矾土基β-SiAlON 氧化性研究%Investigation on oxidation resistance of bauxite-basedβ-SiAlON powders with different particle size

    Institute of Scientific and Technical Information of China (English)

    朱晓燕; 刘新红; 马腾

    2014-01-01

    The oxidation characteristics of bauxite-based β-SiAlON powders with different particle size (d 50 =43.62 μm,d 50 =21.06 μm and d 50 =10.05 μm)at 20 -1400 ℃ have been studied by TG-DTA, XRD and SEM.The results show:(1 )The initial oxidation temperature of β-SiAlON powders with different particle size is about 800 ℃, while oxidation rate increases noticeably when oxidation temperature is above 1 100 ℃.The finer theβ-SiAlON particle size is,the more weight gains,indicating that the oxidation extent is high.(2)The oxidation products of β-SiAlON are cristobalite,mullite and alumina.The finer the β-SiAlON particle size is,the stronger the peaks of cristobalite,mullite and alumina are,and oxidation is more noticeable.(3 )Glass film containing needle-like mullite on the surface ofβ-SiAlON particles is formed which will retard O 2 diffusion to protect β-SiAlON from being further oxidized.%用热重分析仪(TG-DTA)、X 射线衍射仪(XRD)和扫描电子显微镜(SEM)研究了三种不同粒度(d 50=43.62μm、d 50=21.06μm 和 d 50=10.05μm)的矾土基β-SiAlON 粉体在20~1400℃温度范围内非等温氧化的特性。结果表明:(1)三种粒度的β-SiAlON 试样均从800℃开始氧化,氧化温度高于1100℃后,试样的氧化速度加快,且粒度越小,氧化增重越明显,表明氧化程度越高。(2)β-SiAlON 氧化后产物为方石英、莫来石和氧化铝。β-SiAlON 粒度越小,方石英、莫来石及氧化铝峰越强,氧化越剧烈。(3)β-SiAlON 氧化后,表面形成含针状莫来石的玻璃膜,可阻止氧气进入β-SiAlON 粒子内部,形成保护性氧化。

  4. Fungos micorrízicos arbusculares em estéril revegetado com Acacia mangium, após mineração de bauxita Colonization of arbuscular mycorrhizae fungi in substrate, after bauxite mining, vegetated with Acacia mangium

    Directory of Open Access Journals (Sweden)

    Ana Lucy Caproni

    2005-06-01

    Full Text Available O objetivo deste trabalho foi avaliar a composição das comunidades de FMAs em áreas revegetadas com Acacia mangium após a mineração de bauxita na região de Porto Trombetas, PA. Foram coletadas amostras de solo compostas nos períodos seco e chuvoso, em áreas revegetadas com Acacia mangium, que receberam inóculos de Glomus clarum e Gigaspora margarita, com 1 e 5 anos de idade. Os solos foram revegetados sem a reposição do horizonte superficial orgânico. Os esporos dos fungos micorrízicos arbusculares (FMAs foram extraídos e identificados através de suas características morfológicas. Analisou-se a densidade de esporos e de espécies em cada amostra, a densidade relativa e a freqüência de ocorrência de cada espécie por período de amostragem, além do índice de abundância e freqüência (IAF. Sob o plantio de mudas de A. mangium, a densidade de esporos de FMAs foi elevada e aumentou com a idade, enquanto o número de espécies não variou. Glomus clarum produz alta densidade de esporos na fase inicial do plantio e declina com o tempo, e Gigaspora margarita não esporula nas condições edafoclimáticas locais. A maioria das espécies de FMA não apresenta o mesmo padrão de esporulação nos períodos seco e chuvoso.The objective of this work was to monitor the establishment of Gigaspora margarita and Glomus clarum in reclaimed areas after the bauxite mining in Porto Trombetas, PA, Brazil. Soil samples were collected during the dry and rainy periods under one and five-year-old Acacia mangium trees grown from seedlings that had been inoculated with Glomus clarum and Gigaspora margarita. The exposed subsoil was managed without replacing the organic soil layer. FMA spores were extracted and identified through their morphologic characteristics. Spore density and frequency of each species were determined in each sampling The index of abundance and frequency (IAF were estimated for all samples. Under A. mangium the arbuscular

  5. EH-4电导率成像系统在铝土矿找矿中的应用研究%AN APPLICATION OF EH-4 CONDUCTIVITY IMAGING SYSTEM FOR EXPLORATION OF BAUXITE DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    陈炳武; 李怀京

    2012-01-01

    This paper briefly introduces the basic principle and method of the EH-4 conductivity imaging system. The stability of the system, the ability for vertical electrical layered recognition, the detecting ability for typical electrical structure of the mining area and the usability of the system for complex conditions were tested by the test in the Leigou Mine Area, Mianchi County of Henan province. Through the application of wavelet multi resolution analysis mathematical method, the measured data has been processed by a first-order multi-resolution decomposition, and the data has been separated into first order detailed a-nomaly and approximation of abnormal. By contrasting with the information of the well ZK808 of mining area, it is illustrated that First order detail anomaly contains more noise and static effect and the first-order approximation abnormalities included the more target geological anomaly information, thereby effectively suppressing noise and static effect have been done, and the target geological anomaly information has been highlighted. Using a first order approximation of data, two dimensional joint inversion was done. By contrasting with the results of two-dimensional inversion and the mine area geological data, it is confirmed that the prospecting effect and the prospect of application of the EH-4 conductivity imaging system for exploration of bauxite deposits.%简要介绍了EH-4电导率成像系统的基本原理和工作方法.在河南省渑池县雷沟铝土矿区的找矿试验中,测试了系统的稳定性、垂向电性分层能力及对矿区典型电性结构的探测能力和复杂条件的适用能力.应用小波多分辨分析的数学方法对实测数据进行了一阶多分辨分解,分离出一阶细节异常和一阶逼近异常.比对矿区ZK808孔资料,说明了一阶细节异常包含了较多的噪声和静态效应,而一阶逼近异常包含有较多的目标地质体的异常信息,从而有效地压制了噪声及

  6. Ocorrência de Fungos Micorrízicos Arbusculares em resíduo da mineração de bauxita revegetado com espécies arbóreas Arbuscular mycorrhizal fungi occurrence in bauxite mining residue planted to tree species

    Directory of Open Access Journals (Sweden)

    Ana Lucy Caproni

    2007-03-01

    Full Text Available Avaliou-se a ocorrência de fungos micorrízicos arbusculares (FMAs em tanques contendo resíduo da mineração de bauxita cultivados com espécies arbóreas inoculadas com Glomus clarum Nicol. & Schenck e Gigaspora margarita Becker & Hall na fase de viveiro. Acacia holosericea A. Cunn. ex G. Don juntamente com Sesbania virgata (Cav. Pers. ou uma mistura de várias espécies foram transplantadas em tanques contendo resíduo de bauxita. Coletaram-se amostras de resíduos em agosto/1998 (estação seca e abril/1999 (estação chuvosa, extraíram e identificaram-se os esporos de FMAs. Determinaram-se a densidade dos esporos de FMAs, a densidade relativa, a freqüência de ocorrência de cada espécie por período de amostragem e o índice de abundância e freqüência (IAF. A densidade dos esporos e a diversidade das espécies de FMAs foram baixas sob ambas as coberturas. Um maior número de esporos de Glomus clarum, e alto IAF, foram detectados no substrato cultivado com Acacia holosericea e Sesbania virgata na época seca. Isto também ocorreu em ambas as áreas na época chuvosa. Não foram encontrados esporos de Gigaspora margarita em ambas as áreas, nas duas épocas. Independentemente da inoculação, verificaram-se esporos de Archeospora leptoticha (Schenck & Smith Morton & Redecker, Entrophospora colombiana Spain & Schenck, Acaulospora mellea Spain & Schenck e Glomus macrocarpum Tulasne & Tulasne em abundância.The establishment of arbuscular mycorrhizal fungi (AMF was evaluated in two areas of bauxite mining residue planted to tree species inoculated with Glomus clarum Nicol. & Schenck and Gigaspora margarita Becker & Hall in the nursery phase. Acacia holosericea A. Cunn. ex G. Don and Sesbania virgata (Cav. Pers. and a mixture of several tree species were transplanted to deposits of containing bauxite mining residue. In August, 1998 (dry season and April, 1999 (rainy season residue samples were collected and AMF spores extracted and

  7. Determination of Fe_2O_3,TiO_2 and SiO_2 in bauxite by inductivelycoupled plasma-atomic emission spectrometry%ICP-AES法测定矾土中Fe2O3、TiO2和SiO2

    Institute of Scientific and Technical Information of China (English)

    郝荷芳; 苑利

    2011-01-01

    采用四硼酸锂熔融试样,电感耦合等离子体原子发射光谱法(ICP-AES法)测定矾土中Fe2 O3、TiO2和SiO2。通过对熔样方法选择、铝基体以及背景的研究,确定了分析条件。结果表明,该法具有良好的精密度和准确性,回收率在94%~108%。%A method based on inductively coupled plasma-atomic emission spectrometry(ICP-AES) was established for the determination of Fe2O3,TiO2 and SiO2 in bauxite.The sample was melted into lithium tetraborate.The analysis conditions were obtained by studying the melted methods,Al matrix and background.The recommended method showed satisfying precision and accuracy as well.The recovery percents detected by standard addition method were in range of 94%~108%.

  8. 应用层次分析法确定土地复垦适宜性评价指标权重--以登封市某铝土矿矿山土地复垦为例%application research of ahP in the Weights of land suitability evaluation index-a case study on a Bauxite Mine-land reclamation in dengfeng city

    Institute of Scientific and Technical Information of China (English)

    冯乃琦; 刘超; 朱立杰

    2014-01-01

    Mining led to the destruction of land resources, and harm to human production and lives. on the basis of the theory of analytic hierarchy process(ahP), this paper selects nine index to make quantitative evaluation on the weights of the land reclamation suitability evaluation index of a Bauxite Mine-land reclamation in dengfeng city, providing a basis for future work.%矿山开采导致土地资源破坏,给人类生产生活带来危害。文中选用了9个土地复垦适宜性评价指标,应用层次分析法对登封市某铝土矿矿山土地复垦适宜性评价指标进行了定量评价,为今后解决类似问题提出了办法。

  9. Carbono orgânico, nitrogênio total, biomassa e atividade microbiana do solo em duas cronosseqüências de reabilitação após a mineração de bauxita Soil organic carbon, total nitrogen, microbial biomass and activity in two rehabilitation chronosequences after bauxite mining

    Directory of Open Access Journals (Sweden)

    Marco Aurélio Carbone Carneiro

    2008-04-01

    reas de referência a partir do primeiro ano, enquanto para o CO e o Nt estes só foram alcançados de modo consistente em períodos mais longos de reabilitação (18 anos. O coeficiente metabólico (qCO2 foi indicativo do estresse provocado pela mineração, mas não diferenciou os diferentes tempos de reabilitação. Os resultados deste estudo mostram que os atributos essenciais ao funcionamento adequado do solo são recuperáveis pela revegetação.Mining is a human activity with a harsh impact on ecosystems. The degradation degree depends on the intensity of soil impact, exploited soil volume and amount of mine spoil. Soil microbial activities are responsible for key functions in ecosystems and can indicate the degree of rehabilitation of mined areas. The purpose of this study was to evaluate the impact of bauxite mining in two chronosequences with different rehabilitation strategies (revegetation on the following soil attributes: organic carbon (C org, total nitrogen (Nt, microbial biomass and respiration, and enzymatic activities. The study was developed in mining areas owned by Alcoa S/A in two different environments: (a areas originally covered by a tropical prairie vegetation called "campo", at elevations up to 1,000 masl, and (b in hilly areas, on the plateau top, including remnants of the native vegetation cover, represented by a subtropical decidous forest, at elevations about 1.600 masl, called "serra". Rehabilitation differed depending on strategies and time, varying from recent mining to 19 years of rehabilitation. Composite samples were collected in eight "campo" and nine "serra" areas, in two layers (0-10 and 10-20 cm in the winter as well as in the summer, in three replicates. Bauxite mining caused a negative impact on org C, Nt and microbial biomass (C, N and P. The values of these attributes were reduced by up to 99 % in comparison with those in reference areas (native vegetation. In both "campo" and "serra", the C org, Nt, microbial biomass and

  10. Characteristics of bryophytes with gemmae from a karst bauxite mine:A case study of Lindai mine in Zhanj ie town,Qingzhen,Guizhou%贵州喀斯特铝土矿具芽胞苔藓种类特征--以贵州省清镇市林歹铝土矿区为例

    Institute of Scientific and Technical Information of China (English)

    殷声锋; 王智慧; 张朝晖

    2014-01-01

    对贵州省清镇市站街镇林歹铝土矿第二矿区的油菜种植区、矿土上部树林区、废石堆积区、矿土堆积恢复区4类环境进行苔藓植物采集,并对具芽胞苔藓种类进行统计分析,结果表明:(1)经鉴定发现苔藓植物10科22属37种,优势种(频度大于10%)为日本大丛藓Molendoajaponica Broth.(18.72%)和银叶真藓Bryumargenteum Hedw.(11.06%);(2)发现8种具芽胞苔藓,占总种数的21.62%,隶属于丛藓科 Pottiaceae 和真藓科 Bryaceae,其中日本大丛藓和芽胞银藓Anomobryumgemmigerum Broth.为常见具芽胞苔藓;(3)油菜种植区中具芽胞苔藓种类最多(6种),但出现频度不高,非该类环境中的优势种,日本大丛藓在 4类环境中均有发现;(4)在 4类环境中,相对恶劣条件下具芽胞苔藓出现的几率更大;(5)瘤根真藓 Bryum bornholmense Winkelm.& Ruthe.和毛状真藓 Bryum apiculatum Schwagr.的芽胞长于假根上,其余种类芽胞均见于叶腋处,呈扫帚状,芽胞形态上呈现多样性,有球形、棒形、棒槌形、芽形、纺锤状和火炬状。%Bryophytes were collected from four different habitats in Lindai #2 bauxite mine in Zhanjie town, Qingzhen City,Guizhou Province,and the bryophytes with gemmae were statistically analyzed.The result showed that,(1)120 samples were collected from sampling sites,and 10 families,22 genera and 37 species were identified.The dominant species (frequency >10%)were Molendoa japonica Broth (18.72%)and Bryumargenteum Hedw.(11.06%).(2)8 kinds of bryophytes had gemmae,which were attached to Potti-aceae and Bryaceae,accounting for 21.62% of the total.Of these,Molendoajaponica Broth and Bryumar-genteum Hedw.were common bryophytes with gemmae,found in 44 samples and 16 samples respectively. (3)The largest quantities of bryophytes with gemmae were found in areas where rape was cultivated (6 spe-cies);however,frequency was low and there was no dominant species.Additionally,Molendoa japonica Broth

  11. Respostas de Acacia mangium Willd e Sclerolobium paniculatum Vogel a fungos micorrízicos arbusculares nativos provenientes de áreas degradadas pela mineração de bauxita na Amazônia Responses of Acacia mangium Willd and Sclerolobium paniculatum Vogel to native arbuscular mycorrhizal fungi from remaining areas of bauxite mining in Amazon

    Directory of Open Access Journals (Sweden)

    Ney Freitas Marinho

    2004-03-01

    Full Text Available A resposta de Acacia mangium Willd (mangium e Sclerolobium paniculatum Vogel (tachi à inoculação de fungos micorrízicos arbusculares (FMA, oriundos de áreas em recuperação após a extração de bauxita, foi avaliada em experimento com delineamento inteiramente casualizado, com 14 tratamentos (duas espécies leguminosas e sete tipos de solo e três repetições. Avaliou-se o número de esporos no solo, a colonização micorrízica, a matéria seca total, o P acumulado, a dependência micorrízica das mudas, e a abundância e a freqüência de espécies. O número de propágulos infectivos (NPI foi estudado em delineamento em blocos casualizados, com oito diluições de solo inóculo, cinco repetições e uma planta isca (Brachiaria decumbens Stapf. Utilizou-se substrato da mistura de um Planossolo mais areia lavada e fosfato de rocha araxá (0,60 g/kg. O número de esporos aumentou em função do tempo de cobertura das leguminosas. A colonização micorrízica foi mais intensa no tachi. Os valores de matéria seca dessa espécie foram inferiores aos de mangium, que por sua vez extraiu em torno de seis vezes mais P do substrato. Em geral, mangium, ao contrário do tachi, foi facultativa à presença dos FMA, sugerindo sua utilização na recuperação de áreas degradadas sem inoculação prévia. Dentre as 39 espécies de FMA identificadas, Glomus macrocarpum Tul. & Tul. apresentou maior índice de abundância e freqüência (IAF e maior NPI, destacando-se entre as espécies pioneiras, ao passo que outras apareceram apenas em estádios sucessionais mais avançados das áreas em recuperação.The responses of Acacia mangium Willd (mangium and Sclerolobium paniculatum Vogel (tachi to arbuscular mycorrhizal fungi (AMF inoculation collected from areas under reclamation after bauxite mining, was evaluated in an completely randomized design distributed in 14 treatments (two legume, species and seven soil types, with three replicates. Evaluated

  12. BEHAVIOR OF BRACATINGA (Mimosa scabrella AND SESBANIA (Sesbania sesban IN DEGRADED AREAS BY DISPOSAL RESIDUE FROM BAUXITE PROCESSING = COMPORTAMENTO DE BRACATINGA (Mimosa scabrella E SESBÂNIA (Sesbania sesban EM ÁREAS DEGRADADAS PELA DISPOSIÇÃO DE RESÍDUOS PROVENIENTES DO PROCESSAMENTO DA BAUXITA

    Directory of Open Access Journals (Sweden)

    Maria Madalena Ferreira Chaves

    2002-01-01

    Full Text Available Topsoil return in mining activities is a common and extensively usedprocedure. But, for some companies this operation may represent around 70-80% of all costs to reclaim degraded areas. This study evaluated the contribution of two leguminous species to improve the initial colonization of a damaged land by bauxite residue disposalafter processing in Poços de Caldas-MG. Plants of Mimosa scabrella ("bracatinga" e Sesbania sesban ("sesban" were planted in January of 1999. Plants were spaced in 2 x 1,5 m and each plot received 25 plants. The statistical alignment was of randomized blocks in the factorial proportion (3 x 4 x 2, with three of the gypsum dosage, four for the thickness layer of superficial soil laid over the residue and two species. Four repetitions were done, with five plants each. Measurements of total height were made and mortality rates were calculated. The results showed that the residue presented similarproperties to a sodium-salt soil, with high pH value and electric conductivity. It was also observed that the gypsum doses, the layer thickness, and the species has significant influences in the average values registered for the variables studied. An inversely proportional relation was observed between the mortality rate and the variable gypsum dosage and layer thickness of the utilized soil, in which the increase of gypsum dosage and layer width corresponded to decreased mortality rate for the species. For all the variables studied, "sesban" showed better performance than "bracatinga". = O retorno de horizontes superficiais do solo para áreas degradadas poratividade de disposição de resíduos tem sido prática rotineira e largamente utilizada. Para algumas empresas, no entanto, essa operação tem representado cerca de 70 a 80% dos custos finais de recuperação de áreas mineradas. O presente trabalho teve como objetivoavaliar a contribuição de duas espécies leguminosas na colonização inicial de um solo degradado pela

  13. China Bauxite Reserves Lasting for Less Than 10 Years

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>On the Forum of Sustainable Development of Aluminum Industry 2007 Bose,which was held in Bose,Guangxi at the beginning of Novem- ber,experts pointed out that with the invest- ment increasing in the aluminum industry and the expansion of scale in aluminum mine ex-

  14. Effect of hydroxamic acid polymers on reverse flotation of bauxite

    Institute of Scientific and Technical Information of China (English)

    李海普; 胡岳华; 王淀佐; 徐兢

    2004-01-01

    The effect of hydroxamic acid starch (HAS) and hydroxamic acid polyacrylamide (HPAM) on the flotation of diaspore and kaolinite was investigated by flotation test. It is found that HAS depresses diaspore but activates kaolinite in acidic pulp,while HPAM activates both diaspore and kaolinite in the pH range of 2.0 - 10.5. The measurement of zeta potential shows that both HAS and HPAM can increase zeta potential of negatively charged diaspore, which indicates the existence of chemical bonding or hydrogen bonding between the reagents and diaspore.By covering the collector dodecyl amine(DDA) on diaspore surface, HAS increases the hydrophilicity of minerals and depresses the flotation of diaspore,however HPAM activates the flotation of diaspore by increasing the adsorption of DDA on diaspore surface.

  15. Calculation of infiltration coefficient of precipitation based on long-term observation data of spring water:a case study of ore deposit bearing karst water in Dazhuyuan bauxite mining area in Wuchuan%利用泉水长观资料计算降水入渗系数--以务川自治县大竹园铝土矿区岩溶充水矿床为例

    Institute of Scientific and Technical Information of China (English)

    黄作明

    2016-01-01

    Dazhuyuan bauxite mining area in Wuchuan Autonomous County is a positive landform of mountain platform syncline.The deposits are ore deposits filled with karst water with deep depth of water level.At-mospheric precipitation is the only recharge source of the ground water.In the north,east and west there are escarpments or steep slopes.Metallogenic series and aquiclude occur on the foot of escarpments.A surface watershed is distributed along the upper edge of escarpments with an opening to the west,and forms a com-plete hydrogeological unit.The ground water in the syncline runs from east to west and collects at Meigudong for discharge.The bauxite layer directly touches the thin and discontinuous roof of shale of Liangshan For-mation (P2 l ),and the strong aquifer above of limestone of Maokouqixia Formation (P2m +q )is in direct contact with ore bed,while the karst pipelines are well developed.Therefore,it is more appropriate to apply the water balance method in terms of calculating the water inflow in the mine.The observational data of spring water is used to calculate infiltration coefficient,so as to predict the water inflow in the mine and to evaluate the water yield property of the aquifer.%务川自治县大竹园铝土矿区为高山台地向斜正地形,岩溶充水矿床,水位埋藏较深,大气降水是地下水的唯一补给源,北、东、西为陡崖或陡坡,崖脚为矿系和隔水层,沿陡崖上部边缘分布一条开口向西的地表分水岭,形成完整的水文地质单元,地下水在向斜内由东向西汇集于梅古洞排泄。铝土矿层直接顶板梁山组(P2 l )页岩,厚度小,不连续,其上部茅口栖霞组(P2 m +q )灰岩强含水层与矿层直接接触,并且岩溶管道发育。因此,计算矿坑涌水量的方法用水均衡法较为恰当,即利用泉水观测资料计算入渗系数,从而达到预测矿坑涌水量、评价含水层富水性的目的。

  16. Eficiência de fungos micorrízicos arbusculares isolados de solos de áreas de mineração de bauxita no crescimento inicial de espécies nativas Efficiency of arbuscular mycorrhizal fungi isolated from bauxite mine spoils on seedling growth of native woody species

    Directory of Open Access Journals (Sweden)

    José Geraldo Donizetti Santos

    2008-02-01

    sp. não foi eficiente. Para o açoita-cavalo, os dois isolados de Glomus sp. estudados foram ineficientes. Nenhum dos FMAs isolados da área de mineração de bauxita promoveu crescimento superior ao obtido com o tratamento-referência com G. etunicatum. No entanto, os isolados do campo Gigaspora sp., Paraglomus occultum e Acaulospora spinosa foram tão eficientes quanto G. etunicatum em promover crescimento das quatro espécies vegetais. Os resultados indicam que mesmo áreas tão degradadas como aquelas submetidas à mineração de bauxita podem conter populações de FMA eficientes, que podem contribuir para reabilitação da área.Arbuscular mycorrhizal fungi (AMF establishing efficient symbiosis with plants play an important role on ecosystem sustainability and can be useful for revegetation of degraded lands. Symbiotic efficiency is related to AMF genotypes and plant species, as well as to environmental conditions that may affect the expression of symbiotic relationships. Thus, the first step to an efficient AMF symbiosis management is to study fungal variability regarding the efficiency with different host species. In this study root colonization and efficiency of several AMF isolates, obtained from bauxite minespoil areas from two distinct environments ("serra" and "campo", were evaluated for seedling growth of pioneer species [aroeira (Schinus terebenthifolius and trema (Trema micrantha], and secondary species [açoita-cavalo (Luehea grandiflora and sesbânia (Sesbania virgata], in a low fertility soil. The experiment was carried out under greenhouse conditions, for 120 days. Each plant species, was treated with ten AMF inoculation types (AMF isolates or their mixtures: Acaulospora longula, Paraglomus occultum, Glomus sp., Gigaspora sp., Acaulospora spinosa, and the mixture of all "campo" species; Acaulospora scrobiculata, Paraglomus occultum, Glomus sp. and the mixture of all "serra" species. For a comparison two additional treatments were included: one

  17. Densidade e diversidade fenotípica de bactérias diazotróficas endofíticas em solos de mineração de bauxita, em reabilitação Density and phenotypic diversity of endophytic nitrogen fixing bacteria in soils under rehabilitation after bauxite mining

    Directory of Open Access Journals (Sweden)

    R. Melloni

    2004-02-01

    diversidade fenotípica no ambiente estudado.Diazotrophic endophytic bacteria enhance plant growth through biological nitrogen fixation and production and release of plant growth regulating substances, which facilitate the revegetation of areas degraded by human activities. However, little is known about populations of such bacteria in soils or plants of mining areas. Aiming to study the effects of different vegetation types and rehabilitation periods on some endophytic diazotrophic bacteria species, soil samples were collected under two environmental conditions ("Campo" and "Serra" in bauxite mined areas undergoing different rehabilitation processes. Population densities were evaluated by the most probable number method in media (NFb, JNFb, and Fam for Azospirillum brasilense and A. lipoferum, Herbaspirillum spp. and A. amazonense, respectively and ranged from 0 to 2.0 x 10(4 bacteria g-1 soil. The vegetation types affected the diazotrophic populations. Highest densities were found in mined soils revegetated with the grass species brachiaria (Brachiaria decumbens, rye grass (Lolium multiflorum and capim-gordura (Melinis minutiflora. However, these densities are considered low compared to those found in agricultural soils. No relationship was found between the rehabilitation time and population density. Thirty-six cultural phenotypes were found on potato medium among 72 isolates out of all three culture media. At a similarity of at least 63 %, these isolates formed seven great groups, five of which (comprising 62.5 % of the total isolates contained the type strains of Burkholderia brasilensis, Herbaspirillum seropedicae, and Azospirillum spp. (A. brasilense, A. amazonense, A. lipoferum, A. irakense. In spite of its low density, this group of bacteria presented a high phenotypic diversity in the studied environment.

  18. Caracterização fenotípica e diversidade de bactérias diazotróficas associativas isoladas de solos em reabilitação após a mineração de bauxita Phenotypic characterization and diversity of diazotrophic associative bacteria isolated from soils rehabilitated after bauxite mining

    Directory of Open Access Journals (Sweden)

    R. S. A. Nóbrega

    2004-04-01

    eles.Grass species, which are frequently used for rehabilitation of degraded areas, can establish root associations with nitrogen fixing bacteria thus contributing to the ecosystem's sustainability. On the other hand, microbial diversity plays an important role in the resilience of biological processes, including N2 fixation. This study aimed at the phenotypic characterization of 72 diazotrophic Gram-negative bacteria. Samples were isolated from areas under different rehabilitation strategies after bauxite mining in Poços de Caldas, Minas Gerais, Brazil, and inoculated in NFb, Fam, and JNFb media. Type and reference strains of Herbaspirillum, Azospirillum and Burkholderia species were used for comparison as they are able to grow in such media. The similarity dendrogram based on seven cultural characteristics of the isolates in GNA medium presented a great diversity, as 50 groups were formed with 81 % similarity. NaCl tolerance in the potato/sucrose/acid malic medium varied from 0 to 50 g L-1 and allowed a separation of isolates and type strains into five groups. Cell diameters varied from 0.61 to 1.21 µm, and 13 isolates were not similar to the type strains. Fifteen groups with 75 % similarity were formed based on total proteins patterns obtained by polyacrylamide gel electrophoresis (SDS-PAGE. Neither was there any relationship among groups based on the different characteristics, nor between these and the areas of bacteria isolation. Fam and JNFb media detected the target species as well as other unidentified ones. The high phenotypic dissimilarity among isolates and type strains, mainly regarding total protein eletrophoresis profiles suggests that new species could be present within these populations.

  19. China’s Mineral Exploration Market Downturn Causes Decline of Investment in Bauxite

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>According to a survey report conducted recently by China Geological Survey Development Research Center,in the first half of 2014,China’s mineral exploration market continued to decline,with the investment in exploration of non-fuel minerals dropping by13.7%and drilling workload dropping by21.7%.According to statistical analysis of the Center,

  20. Import demand with rational expectations: estimates for bauxite, cocoa, coffee, and petroleum

    Energy Technology Data Exchange (ETDEWEB)

    Husted, S.; Kollintzas, T.

    1984-11-01

    The authors offer a method for establishing the distributed lag structure in import-demand models a priori. They consider a firm that imports raw materials in a world of uncertainty. Traditional considerations of adjustment and inventory holding costs lead to a forward-looking import-decision rule. Linear rational expectations modelling allows transforming the forward-looking rule into a finite distributed-lag specification. While the resulting model is similar in form to earlier empirical models, it is not subject to the ''Lucas Critique.'' The model is fitted to US data over the period 1954-1980. 14 references, 2 tables.

  1. Central Geological Prospecting Fund Newly Added 16.47 Million Tonnes of Bauxite in 2013

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>In 2013,the Central Geological Prospecting Fund(CGPF)Project newly discovered 15 ore fields,including 3 large above ore fields,and 5medium sized ore fields.The reporter learned from the recently published"Annual Report of Central Geological Prospecting Fund Project(2013)"that,from 2006 to 2013 the CGPF

  2. Dependence of radon emanation of red mud bauxite processing wastes on heat treatment.

    Science.gov (United States)

    Jobbágy, V; Somlai, J; Kovács, J; Szeiler, G; Kovács, T

    2009-12-30

    Natural radioactivity content, radon emanation and some other physical characteristics of red mud were investigated, so that to identify the possibilities of the safe utilization of such material as a building material additive. Based on the radionuclide concentration, red mud is not permitted to be used directly as a building material, however, mixing of a maximum 20% red mud and 80% clay meets the requirements. The main aim of this work was to determine the dependence of the emanation factor of red mud firing temperature and some other parameters. The relevant experimental procedure was carried out in two different ways: without any additional material, and by adding a known amount of sawdust (5-35 wt%) then firing the sample at a given temperature (100-1000 degrees C). The average emanation factor of the untreated dry red mud was estimated to 20%, which decreased to about 5% at a certain heat treatment. Even lower values were found using semi-reductive atmosphere. It has been concluded that all emanation measurements results correlate well to the firing temperature, the specific surface and the pore volume.

  3. Henan Cancelled Regional Restriction on Bauxite Resources Allocation for Aluminum Oxide Enterprises

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Henan Province People’s Government recently printed and issued notice to announce the decision to adjust Henan’s key mineral resources allocation policy.Why should the mineral resources allocation policy need adjustment,what’s new about the new policy?

  4. CPI Seeking to Break International Monopoly over Bauxite Mine Resources through an Overseas Arrangement

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>China Power Investment Group(CPI),one of the five power generation groups in China signed an Aluminum Development Project Concession Agreement with the government of Guinea on Sep.6,symbolizing a substantial step in developing its Guinean aluminum base with

  5. Evaluation of the use of different coals in chemical looping combustion using a bauxite waste as oxygen carrier

    OpenAIRE

    Mendiara, Teresa; García Labiano, Francisco; Gayán Sanz, Pilar; Abad Secades, Alberto; Diego Poza, Luis F. de; Adánez Elorza, Juan

    2013-01-01

    The interest in the use of solid fuels such as coal in Chemical Looping Combustion is growing because of the benefits of the direct use of coal in this technology on the reduction of the costs linked to carbon dioxide capture. In CLC, the oxygen needed for the combustion is supplied by a solid oxygen carrier therefore avoiding the direct contact between fuel and air. Focusing on the use of solid fuels in the In-Situ Gasification Chemical Looping Combustion (iG-CLC), the oxygen ...

  6. An experimental comparison of cokriging of regionalised compositional data using four different methods: case study3A Bauxites in Hungary-2

    OpenAIRE

    Jarauta Bragulat, Eusebio; Hervada Sala, Carme; Diblasi, Angela

    2004-01-01

    An important problem in the geosciences is the etimation or prediction or regionalized compositions. In fact, it is usual to deal with data such as percentages, concentrations, ppm,..., and use them to estimate values in other locations. Compositional data have been regarded as difficult to work with because of the so-called constant sum constraint. Following Aitchison(1986), any meaningful satatement abaut a composition can be expressed in terms of logratios, but those transformations, and t...

  7. Alumina Producers in Shandong Province Allied to Win Negotiation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Faced with the soaring bauxite price,five alu- mina producers in Shandong Province jointly established Shangdong Bauxite Import Compa- nies Club to gain a better position in price ne- gotiation with foreign counterparts by getting

  8. Defense Reutilization and Marketing Manual

    Science.gov (United States)

    1990-03-01

    Ore 2,000 pounds Bauxite, metallurgical Ore 20 short tons or jamaica Bauxite, metallurgical Ore 20 short tons or surinam Bauxite, refractory Ore... Amphibian Vehicle (to recipients other than a 3. Army Tanks and other Combat museum): Vehicles: Commandant of the Marine Corps Commander Code LPP-2

  9. Application of synthesized EDS spectra to the differentiation of minerals in bauxite%谱图合成在铝土矿矿物鉴别中的应用

    Institute of Scientific and Technical Information of China (English)

    仓向辉; 王锦; 赵春芳; 郭永恒

    2006-01-01

    本文主要论述用X射线能谱仪的谱图合成功能鉴别铝土矿中诸如高岭石、绿泥石、伊利石等组成相似的矿物,进而利用能谱仪的INCA系统强大的比较、匹配功能达到快速、准确地发现铝土矿中其他微量矿物,为制定利用该矿石生产氧化铝工艺流程提供重要依据.

  10. 均化矾土基铝镁浇注料的渣蚀行为和机制研究%Slag corrosion and its mechanism of homogenized bauxite based Al2O3-MgO castables

    Institute of Scientific and Technical Information of China (English)

    王洛; 韩兵强; 陈庆洁; 杨亚东; 孔为民; 罗琼; 李楠

    2016-01-01

    为了研究均化矾土熟料的使用范围,以质量分数为30%的5~3 mm、20%的3~1 mm、20%的≤1 mm的均化矾土为骨料,以12%的≤0.074 mm的棕刚玉粉、10%的≤0.074 mm的镁砂粉、5%的≤2μm的α-Al2O3微粉、3%的≤0.088 mm的SiO2微粉为基质粉,外加o.2%的减水剂制备了均化矾土基铝镁浇注料,并采用FactSage(R)热化学软件建立了熔渣对该浇注料侵蚀的热化学模型,同时通过动态抗渣侵蚀试验研究了其抗渣侵蚀机制.结果表明:1)渣蚀后接近热面附近的骨料周围会生成较大的裂纹,对试样的抗渣性能产生不利的影响;2)均化矾土基铝镁浇注料与熔渣反应,反应产物为CA6、复合尖晶石、C2AS、CAS2等;3)热化学模拟结果表明,均化矾土骨料与熔渣反应时,表面生成约62.5 μm厚的CA6层,使得其向渣中的溶解为间接溶解,而基质与熔渣反应时,未生成CA6层,故基质向渣中的溶解为直接溶解.

  11. 铝矾土微观结构对硫铝酸盐熟料质量的影响%The Influence of the Microstructure in Bauxite on the Quality of Sulphoaluminate Cement Clinker

    Institute of Scientific and Technical Information of China (English)

    牟善彬; 赵青南; 孙振亚; 苏小萍; 张高科

    2002-01-01

    利用扫描电子显微镜(SEM)研究了两种铝矾土和用两种铝矾土配料煅烧的硫铝酸盐水泥熟料的微观结构形态,探索了铝矾土的的微观结构对硫铝酸盐水泥熟料质量的影响,指出了铝矾土结构密实、硬度大造成生料易磨性差,是最终导致硫铝酸盐水泥快凝的主要原因.

  12. Ignition-proof of High Bauxite Coating for Permanent Mold Casting Magnesium Alloy%镁合金金属型高铝矾土涂料阻燃性的研究

    Institute of Scientific and Technical Information of China (English)

    张亮; 王迎新; 彭立明; 丁文江

    2010-01-01

    研究了镁合金金属型高铝矾土涂料的阻燃性.结果表明,合金液和高铝矾土容易在模具浇道处发生化学反应而导致涂料失效,反应产物为Mg_2Al_3和Mg_2Si.阻燃剂可以减弱镁合金液与高铝矾土的反应,涂料的使用时间随着阻燃剂的增加而延长,试验中阻燃剂的最佳加入量为6%.

  13. Study of lime adding points to reduce consumption of caustic soda in Bayer digestion of bauxite%改变石灰添加点降低铝土矿拜耳法溶出碱耗的研究

    Institute of Scientific and Technical Information of China (English)

    陈文汨; 黄伟光; 陈学刚

    2008-01-01

    拜耳法生产氧化铝过程中的碱耗在生产成本中占很大比例.引起碱耗的主要因素是大部分含硅矿物在溶出过程中生成钠硅渣.根据赤泥的钠硅比(N/S)可以判断碱耗的高低.石灰对铝土矿溶出赤泥N/S有着重大影响.本文试图改变石灰添加点来降低溶出赤泥N/S.试验研究结果表明,在溶出温度下添加石灰乳对降低碱耗效果比较明显,在预热温度区添加石灰乳对降低碱耗有效果,但降低幅度不大,在闪蒸温度区添加石灰乳对降低碱耗没效果,甚至增加碱耗.

  14. 不同二氧化硅微粉对矾土基低水泥浇注料性能的影响%Influences of microsilica on properties of bauxite based low cement castables

    Institute of Scientific and Technical Information of China (English)

    薛海涛; 顾华志; 彭云涛; 彭红; 朱晶晶

    2011-01-01

    Effects of four kinds of microsilica with different chemical compositions and physical properties on flowabili-ty,thermal shock resistance and hot modulus of rupture were investigated. The results indicate that when microsilica with high purity,uniform and centralized particle distribution,smooth surface and good flowabili-ty is added,the castables obtain good flowability.good thermal shock resistance,and high hot modulus of rupture;nevertheless,when microsilica with high contents of carbon and alkali metal,large particle size, rough surface and poor particle dispersion,the castables obtain poor flowability,bad thermal shock resistance, and low hot modulus of rupture.%研究了4种理化性能不同的二氧化硅微粉对矾土基低水泥浇注料流动性、抗热震性和高温抗折强度的影响.结果表明:加入纯度高,杂质含量少,颗粒分布均匀、集中,表面光滑,自身流动性好的二氧化硅微粉,则浇注料的流动性好,抗热震性好,高温抗折强度高;加入碳和碱金属含量高,颗粒粒度偏粗,表面粗糙,自身分散性差的二氧化硅微粉,则浇注料流动性差,抗热震性差,高温抗折强度低.

  15. ECONOMIC GEOLOGY (2)NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>20082329 Chen Wang(China University of Geosciences,Beijing 100083,China) Control Factors on Distribution of Carboniferous Bauxite Deposits in Western Henan Province (Geotectonica et Metallogenia,ISSN1001—1552,CN44—1595/P,31(4),2007,p.452—456,1 illus.,10 refs.) Key words:bauxite,mineralization con- trols,Henan Province

  16. Foreign Dependence of Aluminum Resources has Difficulty to be Reduced Significantly

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>Insufficient resource guarantee ability has long been a bottleneck restricting the development of nonferrous metal industry, and aluminum is no exception. According to data from the China Nonferrous Metal Industry Association, during the "Eleventh Five Year" period China’s bauxite import volume presented a spiral upward trend. In 2010 China’s bauxite import volume

  17. 33 CFR 402.3 - Interpretation.

    Science.gov (United States)

    2010-07-01

    ..., but not otherwise processed) loose or in sacks, including alumina, bauxite, gravel, phosphate rock... bundled; (8) Raw sugar, flour, loose or in sacks; (9) Wood pulp, loose or in bales; and (10) Material...

  18. Regional Applied Research Effort Project (RARE) with Region 8 - Beneficial Use of Red and Brown Mud and Phosphogypsum as Alternative Construction Materials

    Science.gov (United States)

    Red and brown muds are the secondary materials generated from the extraction of alumina from bauxite, an aluminum-containing sedimentary rock (Ref. 2). Phosphogypsum is the secondary material generated by the phosphorous fertilizer industry from phosphate-containing sedimentary ...

  19. Research and Development of Bauxite—based Refractories

    Institute of Scientific and Technical Information of China (English)

    ZHONGXiang-chong

    1996-01-01

    The research work on the microstructure and high temperature mehanical properties of sintered Chinses bauxite(DK type) and the ef-fects of foreign oxide additions (K2O,CaO,TiO,Fe2O3,MgO,ZrO2·SiO2) carried out at our laboratories have been reviewed.Based on these basic research results,bauxite-based high performance refractories have been develped for high temperature applications with success-ful achievements.

  20. Physics and chemistry of minerals under laser processing

    Science.gov (United States)

    Kotova, O.; Leonenko, N.

    2016-04-01

    New experimental data of the influence of laser irradiation on the phase composition minerals of bauxite and red mud and their technological features have been represented. The mechanisms of formation of micro- and nanophases on mineral surfaces under the influence of laser irradiation were shown. It is underlined that changes of condition of surface atoms, concentration of metals, agglomeration of titanium minerals and new phase formation occurred under laser irradiation on bauxites and red mud.

  1. NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20111761 Chen Hua(115 Geological Party,Guizhou Bureau of Geology and Mineral Exploration & Development,Guiyang 551400,China);Deng Chao Analysis on the Metallogenic Environment of Maochang Bauxite in Guizhou Province(Guizhou Geology,ISSN1000-5943,CN52-1059/P,27(3),2010,p.198-201,2 illus.,1 table,8 refs.)Key words:bauxite deposit,Guizhou Province By long time physical and chemical process,the carbonate rock after Central Guizhou uplidft,becomes red clay,after further weathering,the red clay decomposed into the oxide,hydroxide of Al and Fe,in the dissolution hole and depression,it concentrates primary fragmentary tight and earthy karst bauxite ore.Because the variation of landform,it decomposes and cracks again,affords the material source

  2. Impact of mine waste dumps on growth and biomass of economically important crops.

    Science.gov (United States)

    Mathiyazhagan, Narayanan; Natarajan, Devarajan

    2012-11-01

    The present study aimed to investigate the effect of magnesite and bauxite waste dumps on growth and biochemical parameters of some edible and economically important plants such as Vigna radiata, V. mungo, V. unguiculata, Eleusine coracana, Cajanus cajan, Pennisetum glaucum, Macrotyloma uniflorum, Oryza sativa, Sorghum bicolour, Sesamum indicum, Ricinus communis, Brassica juncea, Gossypium hirsutum and Jatropha curcas. The growth rate of all the crops was observed in the range of 75 to 100% in magnesite and 15 to 100% in bauxite mine soil. The moisture content of roots and shoots of all the crops were in the range of 24 to 77, 20 to 88% and 42 to 87, 59 to 88% respectively. The height of the crops was in the range of 2.6 to 48 cm in magnesite soil and 3 to 33 cm in bauxite soil. Thus the study shows that both mine soils reflects some physical and biomolecule impact on selected crops.

  3. NEWS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    <正>Chalco Enters Agreement with Vietnam on Bauxite Project During a State visit to Vietnam headed by China’s President Hu Jintao, Xiao Yaqing, Chairman and CEO of China Aluminium Corp. (Chalco) signed an agreement with his Vietnamese counterpart on the development of a bauxite project in Vietnam. Top officials of the two countries attended the signing ceremony in Hanoi. This project is known to be the largest one between the two countries up to present and it is taken by leaders of both countries as an important progress in promoting the bilateral relations in economy and trade.

  4. Use of clays for purification of biodiesel; Utilizacao de argilas para purificacao de biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Paula, Andreia Juliana Almeida de; Kruegel, Marlus; Miranda, Joao Paulo; Rossi, Luciano Fernando dos Santos; Costa Neto, Pedro Ramos da, E-mail: pedroneto@utfpr.edu.b [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Depts. de Quimica, Biologia e Mecanica

    2011-07-01

    This work describes the results of the purification of methyl biodiesel, obtained by oxidized soybean oil, using different methods. After the ester separation from the glycerin by decanting, the ester was purified each time with distillation, washing with water and adsorption with bauxite, bentonite and attapulgite. The removal of total contamination, unsaponifiable material, concentrations of free glycerin and soap were analyzed in the purified ester phase. The best result of purification was observed with the use of bentonite and bauxite, in the removal of soap and free glycerin respectively. (author)

  5. Metabauxite horizons containing remobilized-origin gem diaspore and related mineralization, Milas-Muğla province, SW Turkey

    Science.gov (United States)

    Hatipoğlu, Murat; Türk, Necdet; Chamberlain, Steven C.; Murat Akgün, A.

    2010-10-01

    Remobilized-origin gem diaspore and related minerals occur as infill within structurally controlled voids that developed in the upper of two distinct karst unconformity-type metabauxite (diasporite) horizons in the İlbir Mountains area of the Milas-Muğla province, SW Turkey. Colour-change diaspore (trademarked as zultanite) and associated mineral specimens (greenish muscovite, chloritoid, donbassite, specular hematite, ilmenite, goethite, and younger calcite) occur in fracture zones (veins and open structures) that cross-cut the metabauxite horizons. The mineralized fracture zones do not extend into the enclosing marbles, probably because of the ductility contrast between the brittle bauxite and relatively plastic carbonate beds. Thick, white to light gray and dark gray limestone beds were deposited in the İlbir Mountains area during the Cretaceous (146-65 Ma), and contain two stratigraphically distinct karst-fill bauxite horizons. Al-, Fe-, Si- and Ti-rich solutions that infiltrated the karstified limestone probably originated from altered schist and gneiss that surround the basin. The limestone beds (>2000 m thick) were subjected to burial metamorphism, forming marble. Subsequently, the marble block was folded during nappe emplacement toward the SSW as part of late Alpine contractional deformation during the Paleogene (65-23.8 Ma). The upper bauxite horizons within the folded block were cross-cut by fracture zones because of their relatively brittle rheology. At this time, increased pressure and temperature in the bauxite horizons resulted in remobilization of the primary constituents of the bauxite within an aqueous complex, resulting in the crystallization of coarse-grained assemblages in the cross-cutting structures. Ultimately, erosion and mineral exploration revealed the steeply dipping bauxite outcrops and mine workings evident today. This paper focuses on the mine geology of surface outcrops of diasporic bauxite, the upper bauxite horizon within

  6. Utilização de argilas para purificação de biodiesel

    Directory of Open Access Journals (Sweden)

    Andréia Juliana Almeida de Paula

    2011-01-01

    Full Text Available This work describes the results of the purification of methyl biodiesel, obtained by oxidized soybean oil, using different methods. After the ester separation from the glycerin by decanting, the ester was purified each time with distillation, washing with water and adsorption with bauxite, bentonite and attapulgite. The removal of total contamination, unsaponifiable material, concentrations of free glycerin and soap were analyzed in the purified ester phase. The best result of purification was observed with the use of bentonite and bauxite, in the removal of soap and free glycerin respectively.

  7. The United States Strategic Stockpile of Critical Minerals and Our National Security.

    Science.gov (United States)

    1982-04-01

    minerals such as columbium, mica, cobalt, manganese, tantalum, chromium, bauxite, nickle, strontium, platium , zinc, etc., it would be impossible to produce...Titanium is 162,669 short tons or 18% of its objective, Tantalum is 4,768,060 lbs. or 33% of its objective and Platium is at 35% of its objective. 3 9...100 Tantalum 0 96 100 0 Bauxite 52 93 100 83 Chromium (-44) 90 99 100 Platium (-45) 89 98 100 Asbestos (-32) 85 97 83 Fluorine 50 82 100 8 Tin 21 81

  8. Pasta aluminosa para o fabrico de isoladores cerâmicos

    OpenAIRE

    Marques, Tiago Filipe Ramires

    2013-01-01

    Este relatório espelha o trabalho desenvolvido ao longo de um estágio na empresa Cerisol que produz isoladores em porcelana para alta tensão. A intenção principal do estágio era desenvolver uma pasta cerâmica aluminosa para o fabrico de isoladores, do tipo C130, designação dada segundo a norma ICE 60672-3 a porcelanas com elevado conteúdo em alumina. Preparou-se uma pasta usando bauxite calcinada como fonte de coríndon. Esta pasta, denominada de PB1 (pasta de bauxite 1), apresentou uma bai...

  9. Developing alternative resources of rare earth elements in Europe - EURARE and the red mud challenge

    Science.gov (United States)

    Deady, Eimear; Mouchos, Evangelos; Goodenough, Kathryn; Wall, Frances; Williamson, Ben

    2015-04-01

    Rare earth elements (REE) are considered to be highly "critical" by the European Commission [1], owing to the concentration of global supply [2] and their use in a wide range of emerging technologies (e.g. smart phones, electric cars and wind turbines). The main source of REE is the mineral bastnäsite, which is primarily extracted from carbonatites. Alternative resources of REE have been identified in a variety of other environments such as alluvial placers, bauxites and ore tailings. The EURARE project (www.eurare.eu), funded by the European Commission, aims to improve understanding of potential REE resources in Europe with the overall objective of establishing the basis for a European REE industry. As a part of this project, alternative sources of rare earth elements in Europe are being considered. REE have been identified as being particularly enriched in karst-bauxites and hence in the red muds generated as a waste product from the processing of these bauxites to alumina through the Bayer process [3]. Karst-bauxites are widely distributed with deposits known across the Mediterranean and with intermittent exploitation occurring over many decades. REE become concentrated in the bauxite deposits by the bauxitisation process and are retained due to the geochemical barrier created by the limestone bedrock below. This can result in several processes, including the crystallisation of authigenic REE-bearing minerals, the accumulation of residual phases and the adsorption of ions onto clays and other mineral surfaces [4]. Red muds produced from alumina processing represent a potentially important concentration of REE as it has been demonstrated that the REE pass through the alumina extraction process into the waste, and the total REE concentrations are typically enriched by a factor of two compared with the original bauxite ore [5]. Bauxites and red muds from the Parnassus Ghiona region of Greece [6] and the Seydişehir-Akseki region of Turkey have been assessed as

  10. Development and Application of Spinel and High—alumina/Spinel Castables

    Institute of Scientific and Technical Information of China (English)

    YANGDean; CHENGGuoxiang; 等

    1998-01-01

    The development and application of domestic spinel and high-alumian/spinel(including corun-dum/spinel and calcined-bauxite/spinel) castables were disucssed in this paper,It expounded the tech-nical characters and virtues of high grade and medi-um grade spinel and the importance of the develop-met and successful application of calcined-bauxite/spinel castalbes.Because of the technical and eco-nomical feasibility,the developement and application of spinel and high-alumina/spinel castables,in which domestic refractory workers play an important role ,have been flurishing.

  11. Some Aspects in the Development of High Performance Refractories for Iron and Steel Making in China

    Institute of Scientific and Technical Information of China (English)

    ZHONG Xiangchong; YE Fangbao

    2005-01-01

    In the past 25 years in China, to meet with the rapid increase in steel production accompanied by adoption of advanced metallurgical technologies, there has been fast development of China's refractories industry in production capacity, in quality improvement and in development of new products. Sophisticated high performance refractory materials mainly based on our rich reserves of magnesite, bauxite and flake graphite have been developed, such as carbon-bonded products, high purity oxide products, bauxite-based low creep and high strength high alumina bricks and LC, ULC and ZC castables. They have been used in blast furnaces, BOFs, EAFs, secondary refining and continuous casting with considerable improvement in service performance.

  12. Refractory Minerals in Henan Province

    Institute of Scientific and Technical Information of China (English)

    JIN Qinguo; LI Jing; LIU Jiehua; LIU Yanjun

    2004-01-01

    Henan province is very rich in refractory minerals of many varieties including silica, dolomite, graphite,pearlite, sepiolite, olivine, and sillimanite group minerals, besides the abundant reserves of fireclay and bauxite,which lay a good foundation for the development of the refractories industry of the province. The paper introduces the reserves, distribution and character of the refractory minerals in Henan province.

  13. Western Mining Strips 2.7 billion Assets Off to Buy Into Qinghai Investment Group

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>According to an announcement by West Mining Co,Ltd on the 10th,the Company plans to strip off assets including coal,bauxite and carbon barely related to its main business-nonferrous metals in order to buy into Qinghai Investment Group Co.,Ltd.(hereinafter referred to as Qinghai Investment Group).

  14. Guangdong Aluminum to Raise RMB 3 billion for New Production Base in Guizhou

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>On July 7, a loan signing ceremony was held between the Guangdong Aluminum Group, China Construction Bank, Hua Xia Bank and Guangzhou Bank Consortium. It is reported that these banks will provide Guangdong Aluminum Group with RMB 30 billion for an alu-minum oxide and supporting bauxite mining project in Guizhou.

  15. China Cancelled Export Tariff for Nine Kinds of Raw Materials

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>In the recently promulgated "Tariff Execution Plan for 2013", among new tariffs implemented since January 1, 2013, tariffs of nine kinds of raw material products including bauxite, coke,yellow phosphorus, fluorite, magnesium, manganese, silicon metal, silicon carbide and zinc exported by China will be lifted.

  16. Effect of different sources of alumina on the microstructure and mechanical properties of the triaxial porcelain

    Directory of Open Access Journals (Sweden)

    G. Gralik

    2014-12-01

    Full Text Available Porcelains composed of kaolin-quartz-feldspar are called triaxial porcelains. The use of alumina as a substitute for quartz in porcelains has been developed for some time. The results show a significant improvement in their mechanical properties, but alumina has a high cost. The possibility of using alternative materials as a source of alumina with lower cost was investigated. In this work, alternative raw materials were used as a source of alumina: refractory bauxite, primary aluminum hydroxide, reprecipitated aluminum hydroxide. Compositions with commercial alumina and quartz were also formulated to better understand the effects of adding these alternative materials. The raw materials were milled, dried, and characterized by analysis of the particle size distribution, X-ray diffraction, and X-ray fluorescence. The compositions were formulated by replacing the different sources of alumina in the formulation of porcelain. The compositions studied were shaped by pressing and sintered at different temperatures (1150-1400 ºC. The results showed that the use of bauxite and aluminum hydroxide as an alternative source of Al2O3 is viable. The impurities contained in refractory bauxite contributed to the lower values of flexural strength found in compositions having refractory bauxite as a source of alumina. The compositions with reprecipitated aluminum hydroxide showed a high mechanical resistance at low sintering temperatures, while compositions with aluminum hydroxide obtained by the Bayer process achieved good results of mechanical strength in a wide temperature range.

  17. THE PROPOSED ALUMINA INDUSTRY AND HOW TO MITIGATE THE RED MUD FOOTPRINT IN GHANA

    Directory of Open Access Journals (Sweden)

    Simon K. Y. Gawu

    2012-12-01

    Full Text Available Bauxite tailings, also known as red mud, are often generated in vast quantities by extracting alumina from bauxites. The relatively complex composition of the red mud, an insoluble residue from bauxite processing, coupled with its fine particle size distribution, high pH, poor settling properties and some toxic rare metal associations, make its disposal problematic. Two locations are being considered for the sitting of a bauxite refinery in Ghana. Since large quantities of tailings is expected to be produced at a selected site efforts need to be geared towards its management to ensure that the red mud footprint is not repeated in Ghana as happened elsewhere. This paper considers the two proposed sites and applies a site ranking criteria to identify the most suitable site, as well as an environmentally suitable disposal technology based on the selected site conditions and the general red mud characteristics. This study could serve as a sustainable development approach in site selection and the choice of disposal technologies.

  18. Assessment of pollutants sequestration in flowing waters using Red Mud

    Science.gov (United States)

    Red Mud, a waste product of bauxite refinement, has already been reported as a non-conventional adsorbent of heavy metals and some other important nutrients, such as phosphorus. Its use has been explored since it is a low cost solid adsorbent with a strong binding capacity. Although there were equil...

  19. War Reserve Materiel Prepositioning Its History, Its Significance, and Its Future

    Science.gov (United States)

    1991-09-01

    Belgium, France Strontium 100 Mexico, Spain Bauxite & Alumina 97 Australia, Jamaica, Guinea, Suriname Cobalt 95 Zaire, Zambia, Canada, Norway Platinum...antitank weapon systems, 109 assault amphibian vehicles, 28 light assault vehicles, 400 electrical generators, 12 cranes, 625 light trucks, 500 cargo

  20. Comparative Power Projectional Capabilities: The Soviet Union and the United States 1980-85.

    Science.gov (United States)

    1981-02-26

    TANTALUM 97 1 7 THAILAND, CANADA. IMALAYSIA. BRAZIL CC3AT 57ZAIRE. BEIG. -LU ZAMBIA, FINLAND a BAUXITE & ALUMINA 93 JAMAICA. AUSTRALIA. SURINAM ...which provides an excellent rapid means of transport from ships which are over the horizon from the objec- tive. At the other is the much slower amphibian

  1. THE PROPOSED ALUMINA INDUSTRY AND HOW TO MITIGATE AGAINST THE RED MUD FOOTPRINT IN GHANA

    Directory of Open Access Journals (Sweden)

    S. K. Y. Gawu

    2012-01-01

    Full Text Available Bauxite tailings, also known as red mud, are often generated in vast quantities by extracting alumina from bauxites. The relatively complex composition of the red mud, an insoluble residue from bauxite processing, coupled with its fine particle size distribution, high pH, poor settling properties and some toxic rare metal associations, make its disposal problematic. Two locations are being considered for the sitting of a bauxite refinery in Ghana. Since large quantities of tailings is expected to be produced at a selected site efforts need to be geared towards its management to ensure that the red mud footprint is not repeated in Ghana as happened elsewhere. This paper considers the two proposed sites and applies a site ranking criteria to identify the most suitable site, as well as an environmentally suitable disposal technology based on the selected site conditions and the general red mud characteristics. This study could serve as a sustainable development approach in site selection and the choice of disposal technologies.

  2. Mineralogical composition and geographical distribution of African and Brazilian periatlantic laterites. The influence of continental drift and tropical paleoclimates during the past 150 million years and implications for India and Australia

    Science.gov (United States)

    Tardy, Y.; Kobilsek, B.; Paquet, H.

    Following the break-up of Pangea at the end of the Jurassic time, the African and South American continents and then India and Australia drifted into the fringes of the equatorial or tropical climatic zone with the humidity varying according to the epochs. India, Brazil and the southern part of East Africa which were previously more arid and probably hotter during the Jurassic, became progressively more humid and cooler. By contrast, West Africa, Central Africa and Australia, formerly subject to very humid climates became subject to warmer and drier climatic conditions. In the first case, the ferricretes were rarely preserved intact but bauxites, generally massive and non pisolitic and essentially formed of gibbsite (Al(OH) 3) are abundant. In the second case, hematite (Fe 2O 3) occurring as nodular ferricretes are extensively developed together with gibbsite-bearing pisolitic bauxites and boehmite (AlOOH). Gibbsite and goethite are hydrated minerals related to humid and rather cool climates, whereas hematite and boehmite are dehydrated minerals related to less humid and warmer climatic conditions. Thus temperature, relative humidity of the atmosphere and the activity of water are the major climatic and thermodynamic parameters controlling the mechanisms of formation, the processes of evolution and the geographical distribution of bauxites and ferricretes. Furthermore, the geographical distribution and the mineralogical composition of ferricretes and bauxites are considered to be controlled not only by the different present-day climates but also and perhaps above all by the succession of paleoclimates during the past 150 million years.

  3. Temperature dependence of crystal structure and digestibility of roasted diaspore

    Institute of Scientific and Technical Information of China (English)

    周秋生; 李小斌; 彭志宏; 刘桂华

    2004-01-01

    Through X-ray diffraction patterns and scanning electronic micrographs, temperature dependence of the crystal structure of roasted diasporic bauxite at different temperatures and the digestibility of roasting production were investigated systematically. The lattice parameters of unit cell for chemically purified diaspore and unequilibrium alumina-contained oxide obtained from the diaspore roasted at different temperatures were determined. It is found that, with roasting temperature increasing, the roasting production changes from the original dense and perfect diaspore crystal into imperfect corundum with many microcracks and small pores on its surface and then into perfect corundum with low digestibility. The optimum roasting temperature with best digestibility is approximately 525 ℃ when residence time is about 25 min. It is thought that the change of crystal structure, formation of microcracks and small pores in the temperature field are the main essential reasons for improving digestibility of diasporic bauxite and its roasting production.

  4. Effect of spinel content on the properties of phosphoric acid bonded high alumina castables

    Institute of Scientific and Technical Information of China (English)

    Zichun Yang; Hongwei Duan; Lin Li; Shuqin Li; Wen Ni

    2003-01-01

    In order to study the effect of fused spinel on the properties of phosphoric acid bonded high alumina castables, samples with different contents of fused spinel were prepared. The results show that when the contents of the fused spinel are between 8% and 16% (mass fraction), the castables have good properties. The castables overcome the shortages of the phosphoric acid bonded high alumina castables with bauxite cement as a hardening promoter. The experiments demonstrate that most of the service properties of the castables with fused spinel are better than those of the normal phosphoric acid bonded castables which use bauxite cement as a hardening promoter. The examination of the materials indicates that free MgO inclusions in the spinel powder can promote the hardening of the castables.

  5. Analysis of Proppant Hydraulic Fracturing in a Sand Oil Reservoir in Southwest of Iran

    OpenAIRE

    Reza Masoomi; Iniko Bassey; Dolgow Sergie Viktorovich; Hosein Dehghani

    2015-01-01

    Hydraulic fracturing is one way to increase the productivity of oil and gas wells. One of the most fundamental successes of hydraulic fracturing operation is selecting the proper size and type of proppants which are used during the process. The aim of this study is optimizing the type and size of used propant in hydraulic fracturing operation in a sand oil reservoir in southwest of Iran. In this study sand and ceramic (sintered bauxite) have been considered as proppant type. Also the various ...

  6. Development and Application of Mullite Brick With High Refractoriness under Load and Low Creep

    Institute of Scientific and Technical Information of China (English)

    ZHANGSheng; WANGRuikun; 等

    2000-01-01

    This paper introduces of the development and applica-tion of heavily burned mullited brick with high reractoriness under load low creep,which is made of andalusie fine and coarse grains (as aggregate),high alumina bauxite produced in Yangquan county,clay produced in Guangxi provine,industrial alumina powder and silliman-ite powder (as matrix material) and a little amount of ad-ditives and bonded with synthetic bond.

  7. A superficial coating to improve oxidation and decarburization resistance of bearing steel at high temperature

    Science.gov (United States)

    Wang, Xiaojing; Wei, Lianqi; Zhou, Xun; Zhang, Xiaomeng; Ye, Shufeng; Chen, Yunfa

    2012-03-01

    The coating material consisted of aqueous slurry of dolomite, bauxite and silicon carbide mixture. Such a coating material when applied superficially on the steel surface not only enhances oxidation resistance but also helps in inhibiting the decarburization even up to 1250 °C. Metalloscope, XRD and TG-DTA thermal analysis revealed that the formation of a newly densified coating comprised of spinels and the reducing atmosphere formed by the oxidation of SiC improved the resistance of oxidation and decarburization.

  8. Effect of different sources of alumina on the microstructure and mechanical properties of the triaxial porcelain

    OpenAIRE

    Gralik,G.; Chinelattot,A. L.; A. S. A. Chinelatto

    2014-01-01

    Porcelains composed of kaolin-quartz-feldspar are called triaxial porcelains. The use of alumina as a substitute for quartz in porcelains has been developed for some time. The results show a significant improvement in their mechanical properties, but alumina has a high cost. The possibility of using alternative materials as a source of alumina with lower cost was investigated. In this work, alternative raw materials were used as a source of alumina: refractory bauxite, primary aluminum hydrox...

  9. East Europe Report, Economic and Industrial Affairs

    Science.gov (United States)

    2007-11-02

    bauxite and clay, paper and cardboard, different yarns , ferrosilicon and ferrochromium, non-alloyed raw aluminum, zinc and untreated alloys, and so on...better results in exports. Agreements between yarns and fabrics producers and producers of ready-made clothing have already been in existence for...noticeable increase of exports based on the higher production of domestic wool, cotton, hemp and silk. It is estimated that through the year 1990, with

  10. New technology of extracting the amount of rare earth metals from the red mud

    Science.gov (United States)

    Martoyan, G. A.; Karamyan, G. G.; Vardan, G. A.

    2016-01-01

    The paper outlined the environmental and economic problems associated with red mud - the waste generated in processing of bauxite ore for aluminum production. The chemical analysis of red mud has identified a number of useful elements including rare earth metals. The electromembrane technology of red mud processing with extraction of valuable elements is described. A possible scheme of separation of these metals through electrolysis is also given.

  11. Acid rain may cause senile dementia

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, F.

    1985-04-25

    Aluminium, released from the soil by acid rain, may be a cause of several forms of senile dementia including Parkinson's disease and Alzheimer's disease. Many upland reservoirs, fed by acid rain, supply homes with water laced with significant amounts of aluminium. Studies in the Pacific have shown that communities living on soils that are extremely rich in bauxite, the rock containing aluminium, have a very high incidence of Alzheimer's disease.

  12. Are We Tracking the Dragon? Ensuring the Intelligence Community is Properly Postured to Monitor an Emerging China

    Science.gov (United States)

    2008-03-01

    76 No.2 (March-April 1997): 33-44; David Zweig and Bi Jianhai, “China’s Global Hunt for Energy,” Foreign Affairs, Vol 84, No 5, (September-October...resources, primarily energy resources, but also materials such as copper, bauxite and uranium. As David Zweig and Bi Jianhai point out, “an unprecedented...2007, as translated by Opensource.gov, accessed April 12, 2007. 98 Zweig and Jianhai, 25. 45 construction and development contracts. Thus, Chinese

  13. Resources to Riches?

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Africa's natural resources can be a cornerstone of development for some countries on the struggling continent Africa is a vast territory with abundant mineral and biological resources, and this is where great hope lies for a better future. Its valuable metallic reserves, which include gold, cobalt, platinum, chromium, manganese, titanium and vanadium, and mineral reserves, such as diamond, bauxite and phosphate, top the world. Its verified oil and natural gas deposits

  14. Minimising reversion, using seawater and magnesium chloride, caused by the dissolution of tricalcium aluminate hexahydrate.

    Science.gov (United States)

    Palmer, Sara J; Frost, Ray L; Smith, Matthew K

    2011-01-15

    The increase in pH and aluminium concentration after the neutralisation of bauxite refinery residues is commonly known as reversion. This investigation reports the extent of reversion in synthetic supernatant liquor and possible methods to reduce reversion. This work is based on bauxite refinery residues produced from alumina refineries, where reversion is a real life situation in neutralised refinery residues. Tricalcium aluminate hexahydrate, a common phase in bauxite refinery residues, has been found to cause reversion. It has been established that reductions in both pH and aluminium from the seawater neutralisation process are due to the formation of 'Bayer' hydrotalcite Mg(7)Al(2)(OH)(18)(CO(3)(2-),SO(4)(2-))·xH(2)O. This is the primary mechanism involved in the removal of aluminium from solution. Increasing the volume of seawater used for the neutralisation process minimises the extent of reversion for both synthetic supernatant liquor and red mud slurry. The addition of MgCl(2)·6H(2)O also showed a reduction in reversion and confirmed that the decrease in aluminium and hydroxyl ions is due to the formation of Bayer hydrotalcite and not simply a dilution effect.

  15. Use of Fluidized Bed Combustion Ash and Other Industrial Wastes as Raw Materials for the Manufacture of Calcium Sulphoaluminate Cements

    Science.gov (United States)

    Marroccoli, M.; Montagnaro, F.; Pace, M. L.; Telesca, A.; Valenti, G. L.

    Calcium sulphoaluminate cements, mainly composed by 4CaO·3Al2O3·SO3 and 2CaO·SiO2, are special hydraulic binders which require limestone, bauxite and gypsum as natural raw materials for their manufacture. In order to save bauxite and natural gypsum, it has been explored the possibility of using, among the raw mix components, FBC waste together with pulverised coal fly ash or anodization mud and, when necessary, flue gas desulphurization gypsum. Mixtures containing limestone (29-39%), FBC waste (30-44%), pulverised coal fly ash (0-13%) or anodization mud (0-32%), bauxite (0-18%) and flue gas desulphurization gypsum (0-8%) were heated for 2 hours in a laboratory electric oven at temperatures ranging from 1150° to 1300°C. The X-ray diffraction patterns on the burnt products generally showed a good conversion of the reactants and a high selectivity degree towards 4CaO·3Al2O3·SO3, particularly at 1250°C.

  16. Distribution of radionuclides in bayer process

    Energy Technology Data Exchange (ETDEWEB)

    Cuccia, Valeria; Oliveira, Arno H. de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear; Rocha, Zildete [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico de Quimica e Radioquimica], E-mail: rochaz@cdtn.br

    2007-07-01

    Natural occurring radionuclides are present in many natural resources. Human activities may enhance concentrations of radionuclides and/or enhance potential of exposure to naturally occurring radioactive material (NORM). The industrial residues containing radionuclides have been receiving a considerable global attention, because of the large amounts of NORM containing wastes and the potential long term risks of long-lived radionuclides. Included in this global concern, this work focuses on the characterization of radioactivity in bauxite and samples of intermediate phases of Bayer process for alumina production, including the end product - alumina - and its main residue - red mud. The analytical techniques used were gamma spectrometry (HPGe detector) and Neutron Activation Analysis. It was found that the bauxite is the major contributor to radioactivity in Bayer process. It has activities of 37+-12 Bq.kg{sup -1} for {sup 238}U and 154+-16 Bq.kg{sup -1} for {sup 232}Th. The intermediate phases and the end product do not carry significant activity, desirable characteristic from the health physics point of view. Sand and red mud carry most part of radionuclides, and the concentrations are higher in the red mud than in the sand. Thus, these solid residues present activities concentrations enhanced, when compared to bauxite. (author)

  17. Mineral deposit formation in Phanerozoic sedimentary basins of north-east Africa: the contribution of weathering

    Science.gov (United States)

    Germann, Klaus; Schwarz, Torsten; Wipki, Mario

    1994-12-01

    The intra- and epicontinental basins in north-east Africa (Egypt, Sudan) bear ample evidence of weathering processes repeatedly having contributed to the formation of mineral deposits throughout the Phanerozoic. The relict primary weathering mantle of Pan-African basement rocks consists of kaolinitic saprolite, laterite (in places bauxitic) and iron oxide crust. On the continent, the reaccumulation of eroded weathering-derived clay minerals (mainly kaolinite) occurred predominantly in fluvio-lacustrine environments, and floodplain and coastal plain deposits. Iron oxides, delivered from ferricretes, accumulated as oolitic ironstones in continental and marine sediments. Elements leached from weathering profiles accumulated in continental basins forming silcrete and alunite or in the marine environment contributing to the formation of attapulgite/saprolite and phosphorites. The Early Paleozoic Tawiga bauxitic laterite of northern Sudan gives a unique testimony of high latitude lateritic weathering under global greenhouse conditions. It formed in close spatial and temporal vicinity to the Late Ordovician glaciation in north Africa. The record of weathering products is essentially complete for the Late Cretaceous/Early Tertiary. From the continental sources in the south to the marine sinks in the north, an almost complete line of lateritic and laterite-derived deposits of bauxitic kaolin, kaolin, iron oxides and phosphates is well documented.

  18. The influence of sea-level changes on tropical coastal lowlands; the Pleistocene Coropina Formation, Suriname

    Science.gov (United States)

    Wong, Th. E.; de Kramer, R.; de Boer, P. L.; Langereis, C.; Sew-A-Tjon, J.

    2009-04-01

    The Pleistocene Coropina Formation largely constitutes the Old Coastal Plain of Suriname. It is exposed fully only in open-pit bauxite mines in the central coastal plain as part of the unconsolidated overburden of Paleocene-Eocene bauxites. This study deals with the stratigraphy, sedimentology and chronology of this formation, and is based on a study in the recently closed Lelydorp-III bauxite mine operated by N.V. BHP Billiton Maatschappij Suriname. The Coropina Formation consists of the Para and Lelydorp Members. We present a detailed lithological subdivision of these members. In the Para Member, four units are discerned which are grouped in two transgressive cycles, both ranging upward from terrestrial towards chenier and coastal mudflat deposits reflecting glacio-eustatic sea-level changes. The sandy sediments represent fluviatile and beach-bar (chenier) deposits, and were supplied by rivers from the Precambrian basement and to a lesser extent by westward longshore coastal drift. Clays, largely derived from the Amazon River and transported alongshore over the shelf, were deposited in extensive coastal mudflats. The Lelydorp Member, also comprising four units, represents a depositional system that is closely comparable to the recent Suriname coastal setting, i.e., a lateral and vertical alternation of mudflat and chenier deposits formed over a period characterised by more or less constant sea level. Palaeomagnetic data indicate a dominantly reversed magnetic polarity in the Para Member, whereas the Lelydorp Member shows a normal magnetic polarity with a minor reversed polarity overprint. The reversed polarities of the Para Member exclude a Brunhes Chron (0.78-0.0 Ma) age, and thus assign it to the Matuyama Chron (2.58-0.78 Ma). This implies that the Coropina Formation is much older than hitherto assumed, and that one or more (long-term) hiatuses are not recognizable in the lithological succession.

  19. Mining-related environmental impacts of carbon mitigation; Coal-based carbon capture and sequestration and wind-enabling transmission expansion

    Energy Technology Data Exchange (ETDEWEB)

    Grubert, Emily

    2010-09-15

    Carbon mitigation can occur by preventing generation of greenhouse gases or by preventing emissions from entering the atmosphere. Accordingly, increasing the use of wind energy or carbon capture and storage (CCS) at coal-fired power plants could reduce carbon emissions. This work compares the direct mining impacts of increased coal demand associated with CCS with those of increased aluminum demand for expanding transmission systems to enable wind power incorporation. Aluminum needs for expanded transmission probably represent a one-time need for about 1.5% of Jamaica's annual bauxite production, while CCS coal needs for the same mitigation could almost double US coal demand.

  20. Suriname - politics, technology, and Third World energy strategy

    Energy Technology Data Exchange (ETDEWEB)

    Auty, R.M.

    Suriname illustrates how some developing countries responded to the oil price shocks by developing domestic energy sources as a substitute for imported oil. Suriname's effort to develop a capital-intensive hydrosmelter aluminum project ran into both technical and political problems despite its economic appeal. A combination of delays, inflation, and disappointing bauxite deposits raised the final cost estimation of the first stage from $460 to $740 million. A military coup slowed the project until the appeal of a green-technology option of small-scale rural development revived interest. The country's response to the 1973 oil shock still lacks coherence. 1 figure, 1 table.

  1. Tropic Testing of Vehicles

    Science.gov (United States)

    2014-08-27

    kilometer track running through tropical forest . The track is a combination of a bauxite/dirt base with grades on the road up to 20 percent and log...TYPE Final 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Test Operations Procedure (TOP) 02-2-817A Tropic Testing of Vehicles 5a...PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) U.S. Army Yuma Proving Ground Tropic Regions Test Center (TEDT-YPT) 301 C. Street Yuma, AZ

  2. The Best of Both Worlds: Supply and Demand China's Role as a Source of Refractory Minerals for Global Markets

    Institute of Scientific and Technical Information of China (English)

    Mike O' Driscoll

    2003-01-01

    China has long been recognised as an important source of refractory raw materials for refractory markets worldwide.Bauxite,magnesia,fused alumina, and refractory clays in particular, have maintained China's strong position as the world's leading supplier of these minerals .However , important changes have taken place ir the structure of Chinese and global supply of these minerals. Moreover, the world refractory market and the minerals trading sector have also undergone a radical transformation that has influenced mineral supply , and shifted end product manufacture to China . This paper highlights these changes and sees how they have impacted on China as a world source of refractory minerals.

  3. Development of Andalusite Bricks for Hot Blast Stove

    Institute of Scientific and Technical Information of China (English)

    KANG Huarong; LI Xianming; DONG Shengying; XUE Wendong; LI Yong; SONG Wen

    2008-01-01

    Low-creep andalusite bricks are characterized by high refractoriness under load, good anti-creep property, high mechanical strength, low porosity, good thermal shock resistance, etc. In this study, low-creep andalusite brick specimens were investigated in the lab using mullite, bauxite and andalusite. Andalusite with the different panicle sizes were used in the experiment and the specimen with the best property was selected as the production standard. In addition, the industrial produced low-creep andalusite bricks were compared with other low-creep bricks. The results show that the developed low-creep andalusite bricks is an excellent material for hot blast stove.

  4. Stratigraphy of Julian and Tuvalian Substage in the Oslica at Muljava Area (Slovenia

    Directory of Open Access Journals (Sweden)

    Stevo Dozet

    2002-12-01

    Full Text Available The Julian and Tuvalian lithologic column in the Oslica area starts with dolomitic breccias with limonitic groundmass and with a bauxite giving evidence of areal expose on the boundary between Cordevolian and Julian. Afterwards, precepitation of carbonate rocks followed. In the lithological interval where the limestone breccias predominate, oncolitic horizons are most characteristic. The Carnian sedimentary succession in the Oslica is terminated by a dolomite with intercalations of marls, bedded micritic limestones and a darkgrey dolomite with a roundish disintegration. The lithological composition and sedimentological characteristics of the succession indicate an origin in the littoral environment.

  5. Paleogeography of the mid-Cretaceous period

    Energy Technology Data Exchange (ETDEWEB)

    Zharkov, M.A.; Murdmaa, I.O.; Filatova, N.I. [Russian Academy of Sciences, Moscow (Russian Federation)

    1995-05-01

    Global lithologic-paleogeographic maps for the Aptian, Albian, Cenomanian, and Turonian stages of the Cretaceous were compiled for the first time using common methods and taking into consideration the paleogeographic environment of continents and oceans. Particular features of the global distribution of arid and humid environments on continents were analyzed to distinguish belts and zones of evaporite and red-bed sedimentation, coal accumulation, and bauxite and kaolin formation. It is shown that climatic zonality and the location of arid and humid environments on continents were dependent on the arrangement of continents and oceans on the surface of the Earth.

  6. Optimizing Location of Bulk Metallic Minerals Processing Based on Greenhouse Gas Avoidance

    Directory of Open Access Journals (Sweden)

    Benjamin C. McLellan

    2011-12-01

    Full Text Available The bulk minerals iron ore and bauxite cause significant greenhouse emissions in their processing to steel and aluminum respectively. The level of these emissions is highly dependent on the source of electrical and thermal energy. However, they also cause significant greenhouse gas emissions from their transportation across the globe for processing. This study examines these minerals from the perspective of greenhouse gas avoidance, examining the location of processing as an option for reducing transportation-based and process-based emissions. The analysis proposes a “radius of reduction” to define the potential for transporting ore to reduce emissions by offshore processing. Overall scenarios for localized steel production indicate potential for 85% reduction of transport emissions in the steel industry and 14% of overall industry emissions. Local high-carbon electricity grids and inefficient production mean that the benefit of reduced transportation is partially counteracted by increased processing emissions. The transportation of all global bauxite to Norway and other nations with low-emissions electricity for production of aluminum could result in an overall reduction of industry emissions of up to 44%.

  7. Prevalent material parameters governing spalling of a slag-impregnated refractory

    Energy Technology Data Exchange (ETDEWEB)

    Blond, E.; Schmitt, N.; Arnould, O.; Hild, F. [LMT-Cachan (ENS de Cachan / CNRS-UMR 8535 / Univ. Paris 6), Cachan (France); Blumenfeld, P. [CRDM / ARCELOR Grande Synthe, Dunkerque (France); Poirier, J. [CRDM / ARCELOR Grande Synthe, Dunkerque (France); CRMHT-CNRS, Orleans (France)

    2004-07-01

    In steel ladle linings, bauxite refractories in contact with iron and steel slag are subjected to complex loadings. To identify the causes of degradation in different reactor linings, a coupling diagram made up of three poles is established: namely, slag impregnation (I), Thermomechanics (TM) and phase transformations (P). The variation of the microstructure and the gradient of the chemical composition resulting from the (I-P) coupling are characterized by microprobe analyses; a natural impregnation tracer is identified. The (I-T) coupling is studied by modeling the refractory lining behavior subjected to a cyclic thermal loading within the framework of the mechanics of porous continua. Parameters governing the location and amplitude of the maximum pore pressure are obtained and their influences are studied. The analysis of the (TM) pole leads to the identification of a thermo-elasto-viscoplastic model for bauxite in various states of slag impregnation. Numerical simulations show that the stress state developed during the heating stages can induce spalling, probably generated by a localized over-pressure of slag. (orig.)

  8. Political Legitimacy of Vietnam’s One Party-State: Challenges and Responses

    Directory of Open Access Journals (Sweden)

    Carlyle A. Thayer

    Full Text Available This article focuses on the challenges to the authority of Vietnam’s one-party state that emerged in 2009 and state responses. Three separate challenges are discussed: opposition to bauxite mining in the Central Highlands; mass protests by the Catholic Church over land ownership issues; and revived political dissent by pro-democracy activists and bloggers. The Vietnam Communist Party bases its claims to political legitimacy on multiple sources. The bauxite mining controversy challenged the state’s claim to political legitimacy on the basis of performance. The Catholic land dispute challenged the state’s claim to legitimacy on rational-legal grounds. Revived political dissent, including the linkage of demands for democracy with concerns over environmental issues and relations with China, challenged the state’s claim to legitimacy based on nationalism. Vietnam responded in a “soft authoritarian” manner. Future challenges and state responses will be debated as Vietnam moves to convene its eleventh national party congress in 2010.

  9. Flood pulse influence and anthropic impact on the chemical composition and energy content of Oryza glumaepatula in an Amazonian lake.

    Science.gov (United States)

    Enrich-Prast, A; Esteves, F A

    2005-08-01

    The aim of this research was to study the flood pulse influence and the anthropic impact caused by bauxite tailings on the chemical composition of O. glumaepatula in Batata lake (PA, Brazil). Sampling was carried out in stands of O. glumaepatula in the low-water, filling, high-water, and drawdown periods in impacted and natural areas of Batata lake. During the low-water and drawdown periods the stands of O. glumaepatula were exposed, and in the filling and high-water periods the water depth was respectively 1.4 and 3.8 m. The collected material was dried at 70 degrees C, ground, and concentrations of total phosphorus, total nitrogen, organic carbon, and energy content were determined. The results indicate that the biomass increase, caused by the rise in water level, has a dilution effect on nitrogen and phosphorus concentrations in O. glumaepatula. The energy contents did not present significant differences in any of the studied periods. The results suggest that from the low water to filling period, nitrogen becomes more limiting to O. glumaepatula in the impacted area, whereas phosphorus becomes more limiting in the natural area. The population of O. glumaepatula contributes to the recovery of the impacted area of Batata lake as the detritus from this species accumulates over the sediment. This accumulation impedes future re-suspension of the bauxite tailings and increases the organic matter and nutrient concentrations in the impacted sediment.

  10. Use of neutralized industrial residue to stabilize trace elements (Cu, Cd, Zn, As, Mo, and Cr) in marine dredged sediment from South-East of France.

    Science.gov (United States)

    Taneez, Mehwish; Marmier, Nicolas; Hurel, Charlotte

    2016-05-01

    Management of marine dredged sediments polluted with trace elements is prime issue in the French Mediterranean coast. The polluted sediments possess ecological threats to surrounding environment on land disposal. Therefore, stabilization of contaminants in multi-contaminated marine dredged sediment is a promising technique. Present study aimed to assess the effect of gypsum neutralized bauxaline(®) (bauxite residue) to decrease the availability of pollutants and inherent toxicity of marine dredged sediment. Bauxaline(®), (alumia industry waste) contains high content of iron oxide but its high alkalinity makes it not suitable for the stabilization of all trace elements from multi-contaminated dredged sediments. In this study, neutralized bauxaline(®) was prepared by mixing bauxaline(®) with 5% of plaster. Experiments were carried out for 3 months to study the effect of 5% and 20% amendment rate on the availability of Cu, Cd, Zn, As, Mo, and Cr. Trace elements concentration, pH, EC and dissolved organic carbon were measured in all leachates. Toxicity of leachates was assessed against marine rotifers Brachionus plicatilis. The Results showed that both treatments have immobilization capacity against different pollutants. Significant stabilization of contaminants (Cu, Cd, Zn) was achieved with 20% application rate whereas As, Mo, and Cr were slightly stabilized. Toxicity results revealed that leachates collected from treated sediment were less toxic than the control sediment. These results suggest that application of neutralized bauxaline(®) to dredged sediment is an effective approach to manage large quantities of dredged sediments as well as bauxite residue itself.

  11. In-situ subaqueous capping of mercury-contaminated sediments in a fresh-water aquatic system, Part II-evaluation of sorption materials

    Energy Technology Data Exchange (ETDEWEB)

    Randall, Paul M., E-mail: randall.paul@epa.gov [U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 W. Martin Luther King Drive, Cincinnati, OH 45268 (United States); Yates, Brian J.; Lal, Vivek; Darlington, Ramona [Battelle, 505 King Avenue, Columbus, OH 43201 (United States); Fimmen, Ryan [Geosyntec Consultants, 150 E. Wilson Bridge Road, Suite 232, Worthington, OH 43085 (United States)

    2013-08-15

    The function and longevity of traditional, passive, isolation caps can be augmented through the use of more chemically active capping materials which have higher sorptive capacities, ideally rendering metals non-bioavailable. In the case of Hg, active caps also mitigate the rate and extent of methylation. This research examined low cost, readily available, capping materials for their ability to sequester Hg and MeHg. Furthermore, selected capping materials were evaluated to inhibit the methylation of Hg in an incubation study as well as the capacity of a selected capping material to inhibit translocation of Hg and MeHg with respect to ebullition-facilitated contaminant transport in a column study. Results indicated that bauxite had a better capacity for mercury sorption than the other test materials. However, bauxite as well as soil capping materials did not decrease methylation to a significant extent. Materials with larger surface areas, higher organic matter and acid volatile sulfide (AVS) content displayed a larger partitioning coefficient. In the incubation experiments, the presence of a carbon source (lactate), electron acceptor (sulfate) and the appropriate strains of SRB provided the necessary conditions for Hg methylation to occur. The column study showed effectiveness in sequestering Hg and MeHg and retarding transport to the overlying water column; however, disturbances to the soil capping material resulting from gas ebullition negated its effectiveness.

  12. NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20110947 Chen Xinglong(Guizhou Bureau of Nonferrous Metal and Nuclear Geology,Guiyang 550005,China);Gong Heqiang Endowment Factors and Development & Utilization Strategy of Bauxite Resource in North Guizhou Province(Guizhou Geology,ISSN1000-5943,CN52-1059/P,27(2),2010,p.106-110,6 refs.,with English abstract)Key words:bauxite deposit,Guizhou Province20110948 Dang Yanxia(Mineral Resource & Reservoir Evaluation Center,Urumiq 830000,China);Fan Wenjun Geological Features and a Primary Study of Metallogenesis of the Wucaiwang Zeolite Deposit,Fuyun County(Xinjiang Geology,ISSN1000-8845,CN65-1092/P,28(2),2010,p.167-170,2 illus.,1 table,5 refs.)Key words:zeolite deposit,Xinjiang Nearly all zeolite deposits in the world result from low-temperature-alteration of glass-bearing volcanic rocks.The southern slope of the Kalamali Mountain is one of the regions where medium to acid volcanics are major lithological type,thus it is a preferred area to look for zeolite deposit.The Wucaiwang zeolite ore district consists of mainly acid volcanic-clastic rocks.

  13. Radiological restrictions of using red mud as building material additive.

    Science.gov (United States)

    Gu, Hannian; Wang, Ning; Liu, Shirong

    2012-09-01

    Red mud remains as residue from the processing of bauxite using different methods. The chemical composition of red mud varies widely with respect to the types of bauxite ore and processing parameters. Red mud samples from Guizhou, China, were investigated using a X-ray fluorescence spectroscope, a quadrupole inductively coupled plasma mass spectrometer and a electron probe micro-analyzer. The results showed that red mud consisted of eight main chemical components--CaO, Al(2)O(3), SiO(2), Fe(2)O(3), TiO(2), Na(2)O, K(2)O and MgO--and dozens of trace elements, including natural radioactive elements, such as uranium and thorium. Gamma spectrometric analysis showed that the values of internal exposure index I (Ra) and external exposure index I (γ) of Guizhou red mud were 1.1-2.4 and 2.3-3.5 respectively. Thus, it should not be used as a main building material indiscriminately. The amount of red mud from Guizhou when it is used for main building materials in China should be less than 28-44%.

  14. [Study on the influence of mineralizer on the structures and spectral properties of calcium aluminates].

    Science.gov (United States)

    Zheng, Huai-Li; Liu, Jun-Yu; Li, Lin-Tao; Li, Fang

    2009-11-01

    The present paper investigated the effect of mineralizer on the structure and properties of calcium aluminates formation. Calcium aluminates powder was synthesized under high temperature calcination by mixing bauxite, limestone and a certain amount of mineralizer. The product structure, compositional information and spectral properties were carefully characterized by XRD, IR and DTA-TG, and the mineralization mechanism of mineralizer was studied during the process of calcium aluminates preparation. The results showed that calcium aluminates powder could be obtained under lower temperature calcination after adding mineralizer to the raw materials. The main products of the reaction were CaAl10 O18 and CaAl2 Si2 O8 without mineralizer, however, the main products of the reaction were CaAl3 BO7 and Ca3 Al10 O18 with mineralizer, in which Al2 O3s could be extracted easily, while CaAl2 Si2 O8 was reduced greatly in which Al2 O3 could not be extracted easily. At the same time, it is easy for calcspar to decompose after adding mineralizer. It is favorable to Al-Si bond break and Al stripping from bauxite. These facts could improve the extraction rate of Al2 O3 from raw materials. Also, in the case of adding mineralizer to the raw mixes, the crystal structure and composition are changed, which is beneficial to reducing calcination temperature.

  15. Preparation and Characteristics of Polyaluminium Chloride by Utilizing Fluorine-Containing Waste Acidic Mother Liquid from Clay-Brine Synthetic Cryolite Process

    Directory of Open Access Journals (Sweden)

    Feng-shan Zhou

    2014-01-01

    Full Text Available Clay-brine process employing activated clay, NaCl, HCl, and HF as raw materials is the primarily advanced technology to synthesize cryolite in the present industrial grade. However, plenty of byproducts of fluorine-containing waste HCl at the concentration of about 10%~12% could not be utilized comprehensively and are even hazardous to the environment. This work proposed a new two-step technology to prepare inorganic polymer flocculants polyaluminium chloride (PAC from synthetic cryolite mother liquor. Many specific factors such as the variety of aluminide source, reaction temperature and time, reagent ratio, and manner of alkaline addition were taken into consideration and their influences on the performances of produced PAC were discussed. It was found that synthetic cryolite mother liquor could react with bauxite and calcium aluminate directly to prepare cheap PAC, with plenty amount of water insoluble CaF2 and CaSiF6 produced as well. However, once HCl was introduced into synthetic cryolite mother liquor as well as by utilizing bauxite as aluminide source and sodium aluminate as adjusting basicity agent, the resultant PAC would dissolve out higher amount of aluminum while producing little amount of water insoluble materials. The coagulation behavior of the specially produced PAC could even match the industrial grade PAC conforming to national standard.

  16. Progress in Research and Development of Refractory Oxide-Nonoxide Composites

    Institute of Scientific and Technical Information of China (English)

    ZHONG Xiangchong

    2008-01-01

    Some of the progress made in our laboratories in collaboration with industry in research and development work on high performance oxide-nonoxide composites for metallurgical applications has been reviewed. (1) SiAlON bonded corundum composites for blast furnace usage have been produced by reduction-nitridation sintering at high temperature, using bauxite instead of alumina in the matrix. (2) Low carbon Al2O3-SiAlON slide plate materials successfully used in high quality steel continuous casting have been developed in which most or all of the graphite in Al2O3-C brick is replaced by bauxite-based β-SiAlON. (3) Al/Si metal bonded Al2O3-C material characterized by low carbon content, low firing temperature and in-situ formation of carbides and nitrides at high temperature during service are found to possess very high hot strength and very good thermal shock resistance and have also been successfully used as slide plates in ladles and tundishes for high quality steel casting.

  17. Application of inorganic-organic composite flocculant on dye wastewater treatment%有机无机复合型混凝剂在印染废水中的应用

    Institute of Scientific and Technical Information of China (English)

    刘桂萍; 祝杏; 王明杰; 王丽多

    2013-01-01

    A new inorganic-organic composite flocculant compounded with chitosan/bauxite was prepared by the simple acid soluble coating method and applied to the dye wastewater treatment. The structure analysis of the complex using SEM and IR indicated that chitosan mainly loaded on the bauxite by simple physical adsorption, but it might be also loaded through chemical absorption with bauxite's aluminum frame. The dosage of flocculant and wastewater pH value were the main factors influencing the results of the wastewater treatment. When flocculant dosage was 3 g/L and pH was 5 , the removal rate of COD and color were above 58% and 87% , respectively, while the removal rate of COD and color of effluent water after A/0 process were above 46% and 83% , respectively.%采用简单的酸溶包覆方法制备了壳聚糖/铝矾土有机无机复合型混凝剂,用于印染废水的处理.通过SEM观察和IR对复合物的结构分析表明,壳聚糖虽然主要以简单的物理吸附方式负载在铝矾土上,但也可能存在壳聚糖与铝矾土中的骨架铝发生化学吸附作用而负载.处理印染废水试验结果表明,混凝剂质量浓度和废水pH值是影响废水处理效果的主要因素.在质量浓度为3 g/L,废水pH =5的条件下,对印染废水COD去除率和色度去除率分别可以达到58%和87%以上;对经A/O工艺处理后沉淀池出水的COD去除率和色度去除率也可达到46%和83%以上.

  18. 高铁水兑入比电炉炉盖用镁铝尖晶石浇注料的研制%Development of magnesium aluminate spinel castable for cover of EAF with high molten iron adding ratio

    Institute of Scientific and Technical Information of China (English)

    陈杨; 吴洪平; 朱冬冬; 张行

    2012-01-01

    Specimens of magnesium aluminate spinel castable and calcium aluminate cement bonded bauxite based castable were prepared using special bauxite (particle size ≤8 mm) and sintered magnesia as aggregates,SiO2 micropowder.cc-alumina micropowder and calcium aluminate cement as binders,drying, firing at 1 350 ℃ and 1 500 ℃ for 3 h,respectively. The bulk density,modulus of rupture,cold crushing strength, permanent change in dimensions on heating, thermal shock resistance and slag resistance were determined. The result shows that compared with calcium aluminate cement bonded bauxite based castable,the magnesium aluminate spinel castable has higher cold crushing strength after drying, better slag resistance but worse thermal shock resistance. Magnesium aluminate spinel based lid of EAF with high molten iron adding ratio has longer service life.%以粒度≤8 mm特级高铝矾土颗粒和烧结镁砂为骨料,SiO2微粉、α-Al2O3微粉、铝酸钙水泥作结合剂,分别制得镁铝尖晶石质浇注料和铝酸钙水泥结合高铝质浇注料.对试样分别进行烘干、1 350℃3 h和1 500℃3 h热处理并检测其体积密度、抗折强度、耐压强度、加热永久线变化、抗热震性和抗渣性.结果表明:与铝酸钙水泥结合高铝质浇注料相比,镁铝尖晶石质浇注料具有较高的烘干耐压强度,优良的抗渣性,但抗热震性较差.因此,在高铁水兑入比的电炉中,镁铝尖晶石质电炉盖表现出了更长的使用寿命.

  19. Estudio de las tierras raras en las bauxitas kársticas del Noroeste de la Península Ibérica

    Directory of Open Access Journals (Sweden)

    Bustillo, M.

    1990-12-01

    Full Text Available The bauxite deposits from Northeastern Iberian Peninsula are geochemically studied in this paper. Major, minor, trace and rare earth elements are determined by ICP spectroscopy in fifteen samples from three different zones: Southpyrenees, Catalánides y Maestrazgo. According to La/Y and europium anomaly values, the sedimentation environment during the genesis of bauxites had an acid and reducent character. This conclusion is agree with Petraschek's (1989 model for this type of ore deposits. The different methods here included (factor analysis, rare earth elements accumulation coefficients, etc. reveal a great homogeneity in the characteristícs of the parent rocks of the different bauxite deposits. These parent rocks had probably an intermediate geochemical character. From a paleogeographic point of view, the parents rocks were related to rocks of permíc-triassic-lower jurassic age.En este trabajo se hace un estudio geoquímico de las bauxitas del Noreste de la Península Ibérica. Los contenidos en elementos mayores, menores, traza y tierras raras son analizados por espectroscopía de Plasma (ICP, analizándose un total de quince muestras de bauxitas distribuidas en tres zonas: Surpirineo, Catalánides y Maestrazgo. De acuerdo con los valores de la relación La/Y y de la anomalía del Eu, el medio de sedimentación durante el proceso de génesis de las bauxitas tendría un carácter ácido y moderadamente reductor, lo que encajaría en el modelo de Petraschek (1989 para este tipo de yacimientos. Los diferentes métodos de estudio (análisis factorial, coeficientes de acumulación de tierras raras, etc., ponen de manifiesto una gran homogeneidad en cuanto a las características de las rocas madre de los diferentes yacimientos de bauxitas. Estas rocas madre tenían, probablemente, un carácter intermedio en relación a su composición química. Desde un punto de vista paleogeográfico, posiblemente dichas rocas madre fuesen materiales de edad P

  20. Geothermal fracture stimulation technology. Volume II. High-temperature proppant testing

    Energy Technology Data Exchange (ETDEWEB)

    1980-07-01

    Data were obtained from a newly built proppant tester, operated at actual geothermal temperatures. The short term test results show that most proppants are temperature sensitive, particularly at the higher closure stresses. Many materials have been tested using a standard short-term test, i.e., fracture-free sand, bauxite, and a resin-coated sand retained good permeability at the high fluid temperatures in brine over a range of closure stresses. The tests were designed to simulate normal closure stress ranges for geothermal wells which are estimated to be from 2000 to 6000 psi. Although the ultra high closure stresses in oil and gas wells need not be considered with present geothermal resources, there is a definite need for chemically inert proppants that will retain high permeability for long time periods in the high temperature formations.

  1. Performance of block lining in the zone of slanted ducts of a coke dry quenching unit

    Energy Technology Data Exchange (ETDEWEB)

    Frolova, L.S.; Drozd, V.I.; Zadorozhnaya, T.A.; Minasov, A.N.; Surenskii, O.N.; Ershov, N.A.; Ignashin, G.I.; Mishin, E.N. (UkrNIIO (USSR))

    1991-01-01

    Discusses service life and wear of concrete blocks used for construction of dry coke quenching chambers. Concrete blocks replaced conventional refractory bricks. A filler from calcinated bauxites and a high-alumina cement were used for concrete block production. The blocks were used for construction of the zones of slanted ducts. Concrete block properties are analyzed: dimensions, weight, ultimate compression strength, open porosity, apparent density, linear shrinkage at 1,400 C and holding for 5 hours, content of calcium, aluminium and iron oxides. Abrasive wear and spalling of the working surface of the slanted duct zone made of the concrete blocks was 1.5-2.0 lower than that of conventional refractory bricks in chambers with the same service life. Tests carried out 8 years long showed that the slanted duct zones made of concrete blocks were characterized by higher abrasion resistance and heat resistance, reduced number of joints and increased rigidity of the slanted duct structure. 4 refs.

  2. Social Metabolism and Environmental Conflicts in India

    Directory of Open Access Journals (Sweden)

    Joan Martinez-Alier

    2014-04-01

    Full Text Available This paper explains the methods for counting the energy and material flows in the economy, and gives the main results of the Material Flows for the economy of India between 1961 and 2008 as researched by Simron Singh et al (2012. Drawing on work done in the EJOLT project, some illustrations are given of the links between the changing social metabolism and ecological distribution conflicts, looking at responses in Odisha to bauxite mining, at conflicts on sand mining, at disputes on waste management options in Delhi and at ship dismantling in Alang, Gujarat. The aim is to show how a history of social metabolism, of socio-environmental conflicts, and of the changing valuation languages deployed by various social actors in such conflicts, could be written in a common framework.

  3. Effect of particle size on microstructure and strength of porous spinel ceramics prepared by pore-forming in situ technique

    Indian Academy of Sciences (India)

    Wen Yan; Nan Li; Yuanyuan Li; Guangping Liu; Bingqiang Han; Juliang Xu

    2011-08-01

    The porous spinel ceramics were prepared from magnesite and bauxite by the pore-forming in situ technique. The characterization of porous spinel ceramics was determined by X-ray diffractometer (XRD), scanning electron microscopy(SEM), mercury porosimetry measurement etc and the effects of particle size on microstructure and strength were investigated. It was found that particle size affects strongly on the microstructure and strength. With decreasing particle size, the pore size distribution occurs from multi-peak mode to bi-peak mode, and lastly to mono-peak mode; the porosity decreases but strength increases. The most apposite mode is the specimens from the grinded powder with a particle size of 6.53 m, which has a high apparent porosity (40%), a high compressive strength (75.6MPa), a small average pore size (2.53 m) and a homogeneous pore size distribution.

  4. 低成本铁水罐罐沿浇注料的研制与应用%Development and application of low cost castables for hot metal ladle edge

    Institute of Scientific and Technical Information of China (English)

    欧阳德刚; 蒋扬虎; 李明晖; 朱善合; 王清方; 罗巍

    2011-01-01

    The castables for hot metal ladle edge were prepared using recycled bauxite castables( w( Al2O3 ) ≥65% ) used in desulphurization lance and grade three bauxite clinker powder as main starting materials,recycled steel fiber as reinforcement and flexibilizer, bauxite cement, SiO2 micropowder, and α-Al2O3 micropowder as complex binders, disthene as high temperature expanding agent, recycled aluminium silicate fiber (length 3-8 mm) as anti-explosion agent. Formulations with 70% recycled castables and different particle size compositions were designed and optimized according to the anti-explosion ability of castables after rapid demoulding and drying. The results of physical properties and petrographic analysis show that the prepared castables has the moderate density, relatively high strength, and proper microstructure,strengthening the compatibility of castables to rapid drying,enhancing the insulating properties and anti-failure ability. The production application shows the castables can not only decrease the repairing cost of the desulphurization hot metal ladle, but also prolong the average one-time-casting-service life of working lining for bauxite brick hot metal ladle edge from 300 to 845 times.%采用w(Al2O3)≥65%的铁水脱硫喷枪用高铝质浇注料的再生料和三级高铝矾土熟料粉为主要原料,再生钢纤维为增强增韧材料,矾土水泥、SiO2微粉和α-Al2O3微粉为复合结合剂,蓝晶石为高温膨胀剂,用后硅酸铝纤维再生料(纤维长度3~8 mm)为防爆剂,设计了再生料加入质量分数约70%,粒度级配不同的铁水罐罐沿浇注料配方,并根据浇注料试样脱模后快速烘烤的抗爆裂性对配方进行了优化,然后进行了实际应用试验.理化性能检测和岩相分析结果表明:所研制的浇注料致密度适中,强度较高,微观结构合理,增强了浇注料对快速烘烤的适应性,提高了工作衬的保温隔热性能和抗破损能力;实际生产应用表明,该

  5. Comparison of deep desulfurization methods in alumina production process

    Institute of Scientific and Technical Information of China (English)

    刘战伟; 李旺兴; 马文会; 尹中林; 武国宝

    2015-01-01

    Several methods of deep desulfurization in alumina production process were studied, and the costs of these methods were compared. It is found that most of the S2− in sodium aluminate solution can be removed by adding sodium nitrate or hydrogen peroxide in digestion process, and in this way the effect of S2− on alumina product quality is eliminated. However, the removal efficiency of2-23SOin sodium aluminate solution is very low by this method. Both S2− and2-23SO in sodium aluminate solution can be removed completely by wet oxidation method in digestion process. The cost of desulfurization by wet oxidation is lower than by adding sodium nitrate or hydrogen peroxide. The results of this research reveal that wet oxidation is an economical and feasible method for the removal of sulfur in alumina production process to improve alumina quality, and provide valuable guidelines for alumina production by high-sulfur bauxite.

  6. Assessment of recycled PET properties for application on oil wells as sand control agents; Avaliacao de propriedades de PET reciclado para aplicacao em pocos de petroleo como agente de contencao de areia

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Alexandre Zacarias Ignacio [PETROBRAS, Rio de Janeiro, RJ (Brazil); Delpech, Marcia Cerqueira [Universidade do Estado do Rio de Janeiro (IQ/UERJ), RJ (Brazil). Inst. de Quimica], e-mail: mcd@uerj.br

    2008-07-01

    The Sand Control is fundamental for oil production in unconsolidated sandstone formations. It consists of the installation of a filter made of stainless steel screens and grained materials (sand control agents) which are, normally, high density inorganic substances (sand, ceramic, bauxite). Shallow formations, near to the sea bed, are more sensitive and need different kinds of sand control agents with low density. The objective of this work was the evaluation of recycled poly(ethylene terephthalate), PET, as sand control agent for oil wells. Pack permeability and thermal stability tests results, after up to six months of exposure to sea water and crude oil, have indicated that the recycled PET kept the necessary characteristics for the proposed application. Also, it was observed that the PET grain pack did not presented significant property modifications in the exposure conditions, when compared to the non-exposed samples. (author)

  7. The Microstructure and Properties of Alumina—Rich Spinel and Its Products

    Institute of Scientific and Technical Information of China (English)

    SHIGan; SUNGeng-chen

    1995-01-01

    The paper describes the effect of chemical composition on the microstructure and properties of spinel specimens synthesized from bauxite and magnesite,The alumina-rich spinel with higher ratio of Al2O3/MgO,with smaller spinel grain,contains more titaniferous mineral and silicate phase compared to the spinel with lower Al2O3/MgO ratio.In the products obtained from alumina-rich spinel and magnesite clinker,the ratio of Al2O3/MgO of spinel decreases,ti-taniferous mineral and silicate phase in the spinel aggregate are changed,and its content tends to degradation,contrasted with original alumina-rich spinel,The products have good high temperature properties.

  8. Method of winning aluminum metal from aluminous ore

    Science.gov (United States)

    Loutfy, Raouf O.; Keller, Rudolf; Yao, Neng-Ping

    1981-01-01

    Aluminous ore such as bauxite containing alumina is blended with coke or other suitable form of carbon and reacted with sulfur gas at an elevated temperature. For handling, the ore and coke can be extruded into conveniently sized pellets. The reaction with sulfur gas produces molten aluminum sulfide which is separated from residual solid reactants and impurities. The aluminum sulfide is further increased in temperature to cause its decomposition or sublimation, yielding aluminum subsulfide liquid (AlS) and sulfur gas that is recycled. The aluminum monosulfide is then cooled to below its disproportionation temperature to again form molten aluminum sulfide and aluminum metal. A liquid-liquid or liquid-solid separation, depending on the separation temperature, provides product aluminum and aluminum sulfide for recycle to the disproportionation step.

  9. Development and Application of Mullite—Composite Brick for Baths Pool of Blast Furnace

    Institute of Scientific and Technical Information of China (English)

    ZHOULei; LIXian-ming; 等

    1994-01-01

    The paper deals with the development and production of mullite-composite bricks for baths pool of balst furnace,Fused corundum,synthetic mullite ,special grade bauxite and a certain amount of additives were used as raw materials to produce corundum-mullite brick and yellow-corundum brick,All of their physical and chemical properties surpass the designed values.Good results have been obtained from the applic-cation in the baths pool of No.7 blast furnace of Anshan I & S Co.(Angang).The silicon content in pig iron decreases by 0.1%-0.2% while the temperature of the hot metal increases by 20℃,The mineral composition and structure have been studied by means of XRD and SEM.

  10. A world of minerals in your mobile device

    Science.gov (United States)

    Jenness, Jane E.; Ober, Joyce A.; Wilkins, Aleeza M.; Gambogi, Joseph

    2016-09-15

    Mobile phones and other high-technology communications devices could not exist without mineral commodities. More than one-half of all components in a mobile device—including its electronics, display, battery, speakers, and more—are made from mined and semiprocessed materials (mineral commodities). Some mineral commodities can be recovered as byproducts during the production and processing of other commodities. As an example, bauxite is mined for its aluminum content, but gallium is recovered during the aluminum production process. The images show the ore minerals (sources) of some mineral commodities that are used to make components of a mobile device. On the reverse side, the map and table depict the major source countries producing these mineral commodities along with how these commodities are used in mobile devices. For more information on minerals, visit http://minerals.usgs.gov.

  11. Effect of red mud addition on the corrosion parameters of reinforced concrete evaluated by electrochemical methods

    Directory of Open Access Journals (Sweden)

    D.V. Ribeiro

    Full Text Available Red mud, the main waste generated in aluminum and alumina production from bauxite ore by the Bayer process, is considered "hazardous" due to its high pH. The high pH also provides greater protection of rebars, which is reflected in the low corrosion potential and high electrical resistivity (filler effect of concrete. The corrosion potential was monitored by electrochemical measurements and the electrical resistivity was evaluated using sensors embedded in concrete test specimens. The results showed that the addition of red mud is beneficial to concrete, reducing its corrosion potential and increasing its electrical resistivity. Red mud proved to be a promising additive for concrete to inhibit the corrosion process.

  12. A GMDH Approach to Modelling Gibbsite Solubility in Bayer Process Liquors

    Directory of Open Access Journals (Sweden)

    Jennifer K. Muller

    2004-02-01

    Full Text Available Abstract: The most widely employed industrial process for producing alumina (Bayer process involves the dissolution of available aluminium hydroxide minerals present in raw bauxite into high temperature sodium hydroxide solutions. On cooling of the solution, or liquor in the industrial vernacular, Al is precipitated from solution in the form of gibbsite (Al(OH3. In order to optimise the process, a detailed knowledge of factors influencing gibbsite solubility is required, a problem that is confounded by the presence of liquor impurities. In this paper, the use of the Group Method of Data Handling (GMDH polynomial neural network for developing a gibbsite equilibrium solubility model for Bayer process liquors is discussed. The resulting predictive model appears to correctly incorporate the effects of liquor impurities and is found to offer a level of performance comparable to the most sophisticated phenomenological model presented to date.

  13. Sustainable development of the minerals sector in the APEC region

    Energy Technology Data Exchange (ETDEWEB)

    Jane Melanie; Kate Penney; Angelica Austin; Chris Rumley; Robert Curtotti

    2007-01-15

    The objectives in this report are to analyse the global market outlook for minerals over the medium term, identify key issues affecting the sustainability of the minerals sector in the APEC region and recommend possible actions to respond to these issues. These issues are structured around the APEC pillars of trade and investment liberalisation; business facilitation; and economic and technical cooperation. The report highlights the need for a strong and effective policy framework to allow APEC economies to capitalise on growth opportunities in global minerals markets. This is an updated version of ABARE Research Report 06.8. Minerals covered are: thermal coal. metallurgical coal, aluminium, alumina, bauxite, copper, gold, iron ores, lead, nickel, tin, uranium and zinc. 15 figs., 19 tabs.

  14. Effect of turning parameters on A16351 T6 by using Design of Experiments

    Science.gov (United States)

    Annigeri, Ulhas K.; Charan, M.; Vishnu Sai, M.; Ram Charan, T.; Rahul Sai, L.

    2016-09-01

    Aluminium is a well known lightest engineering metals. It is the most productive element on the earth crust. It can be extracted from bauxite, kaolinite or nepheline. It can be used in making aeroplane bodies, automobile parts etc. It is mostly used in multiple applications in order to reduce the weight of the component and it has fancy corrosion resistance. In the present study Al 6351 T6 is selected and a plain turning operation is performed on it with the help of design of experiments. The surface roughness of the samples are tested by varying the cutting parameters such as speed, feed, and depth of cut. A mathematical model is developed and the parameter which affects the surface roughness is determined.

  15. FEATURES OF VENTILATION CONDITIONS BY MUSHROOM CULTIVATION IN MINING UNDERGROUND WORKINGS

    Directory of Open Access Journals (Sweden)

    Vladimir Rendulić

    1991-12-01

    Full Text Available The trial cultivation of mushrooms (Agaricus bisporus in one of the dead faces of the »Krš« pit of the Dalmatian bauxite mines Obrovac proved, that an optimal yield can be attained with the domestic mycelium. The decision has been brought to go on with investments into equipment for new growing-site locations in underground workings of the mine. In order to cultivate high-quality mushrooms, the ventilation of growing sites has been particularly considered. Compressive separate ventilation of growing fields has been applied using the main and the return ventilating pipeline, with the air current regulation according to the growing stage (the paper is published in Croatian.

  16. Production of mullite from natural raw materials using mechanical activation; Obtencao de mulita a partir de materias-primas naturais utilizando ativacao mecanica

    Energy Technology Data Exchange (ETDEWEB)

    Feitosa, G.; Pinheiro, D.G.; Chinelatto, A.L.; Chinelatto, A.S.A [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil). Programa de Pos-Graduacao em Engenharia e Ciencia de Materiais

    2009-07-01

    Mullite, ceramic structure consisting by alumina and silica, is present in different ceramic industry, as refractory, white ceramic, titles and advanced ceramics. This is because this material presents high resistance mechanical and high resistance in high temperatures, beyond low expansion coefficients and thermal conductivity. On the other hand, the mullite production needs high temperatures. This work had as objective the production of mullite from natural raw materials, using mechanical activation. Bauxite and quartz had been mixed in the stoichiometric composition and the mixture was submitted to high energy milling for different times. Then non milled powders and milled powders had been sintered in different temperatures. The characterization was made by X Ray diffraction and scanning electronic microscopy. The results demonstrated that the high energy milling affects the mullite formation, decreasing the temperature in that it is formed. (author)

  17. High pressure fracturing in Colombia: a quantum leap

    Energy Technology Data Exchange (ETDEWEB)

    Velasquez, Juan C. [BP Exploration (United Kingdom); Gutierrez, Jim; Ham, Ernesto; Castro, Alberto [BJ Services Company (United States)

    2004-07-01

    Fracturing has become one of the most common stimulation and well completion techniques in petroleum production. Due to the deeper depths and high frac gradients encountered in some areas, various treatments have resulted in early screen outs or aborted operations due to insufficient rate limited by the available treating pressures. A state of the art technology and high pressure equipment including the largest frac pumps (rated at 2,700 hhp) in the world, were used in Colombian fields to overcome these limitations. The reliability of this equipment has allowed the treatment of these wells to operating pressures of up to 18,000 psi and rates in excess of 40 bpm, placing up to 400,000 lbs of bauxite. Bottom hole treating pressures of 25,000 psi also were reached. This paper describes the development of the fracture campaign and relates the jobs performed to date, including the results and lessons learned (author)

  18. Electron microscopy study of red mud after seawater neutralisation; Estudo por microscopia eletronica de transmissao de lama vermelha tratada com agua do mar

    Energy Technology Data Exchange (ETDEWEB)

    Toledo, S.P.; Kiyohara, P.K. [Universidade de Sao Paulo (IF/LME/USP), SP (Brazil); Antunes, M.L.P., E-mail: malu@sorocaba.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil); Frost, Ray [Queensland University of Technology (United States)

    2012-07-01

    Red Mud, residue of Bayer process for extracting alumina from bauxite, is produced in large quantity. This residue is very alkaline and can cause damage to health and the environment. One way to minimize the environmental impact of this residue is neutralization by sea water. The Brazilian Red Mud was treated with sea water. It appears that the initial pH of the samples is reduced to 8. The analysis by x-ray diffraction allows to identify the formation of hydrotalcite and aragonite. The transmission electron microscopy images show that this consists of particles with dimensions between 0.02 to 2 μm. It was possible to identify by EDS/MET particles of magnesium, confirming the formation of hydrotalcite. (author)

  19. Carbonised red mud--a new water treatment product made from a waste material.

    Science.gov (United States)

    Pulford, I D; Hargreaves, J S J; Ďurišová, J; Kramulova, B; Girard, C; Balakrishnan, M; Batra, V S; Rico, J L

    2012-06-15

    Proposals to use red mud, the waste produced by the extraction of alumina from bauxite ore in the Bayer process, as a material for treatment of heavy metal-contaminated water are limited by its inherent alkalinity and variability. Attempts to lower its pH have been largely unreliable. However, an alternative strategy is carbonisation of red mud by catalytic hydrocarbon cracking, which results in a magnetic material of greater surface area. The efficacy of this material has been compared with that of the untreated parent red mud and acidified red mud for the sorption of CrO(4)(2-), Cu(2+) and Pb(2+). Carbonised red mud does not remove CrO(4)(2-) from solution, but shows enhancement of Cu(2+) and Pb(2+) removal. There is an approximate ten-fold increase in removal of Cu(2+) and Pb(2+) by carbonised red mud compared with acidified red mud.

  20. Concretes with red mud coarse aggregates

    Directory of Open Access Journals (Sweden)

    Dênio Ramam Carvalho de Oliveira

    2012-06-01

    Full Text Available Red mud (RM is a mineral waste, residue of the Bayer process used to obtain alumina from bauxite. While the exploration of rolled pebble damages the environment and is much more controlled by the government, the huge RM disposal areas do not stop increasing and polluting soil, rivers and groundwater sources in Amazon. In this work, the material mixtures used to produce coarse aggregates presented up to 80% of RM, 30% of metakaolin and 30% of active silica as recycled waste. Several tests were carried out to determine the aggregates physical properties and to evaluate the mechanical performance of the concretes with the new aggregates, including hydraulic abrasion strength, and the results were compared to the reference ones, i.e. rolled pebble concretes. Additionally, the sintering process neutralizes any toxic substance as occur in some RM products like tiles and bricks, and these results have encouraged an industrial or semi-industrial production of RM aggregates for concretes.

  1. Wear Behavior of Aluminum Alloy 6061-Based Composites Reinforced with SiC, Al2O3, and Red Mud: A Comparative Study

    Science.gov (United States)

    Singla, Yogesh Kumar; Chhibber, Rahul; Bansal, Hitesh; Kalra, Anil

    2015-09-01

    Metal-matrix composites are widely used in shipping, aerospace, automotive, and nuclear applications. Research attempts have been made in the past to reduce the cost of processing of composites, decrease the weight of the composites, and increase the desired performance characteristics. In this research article, an attempt has been made in using red mud obtained as an industrial waste during the production of aluminum from bauxite ore. This article discusses the novel findings of the experimental study on the dry sliding wear behavior of aluminum alloy 6061-based composites reinforced individually with red mud, SiC, and Al2O3. The microstructural characterization of the composites provides the further insight into the structure—wear behavior of the processed composites.

  2. PRODUCTION OF IRON(II SULPHATE(FeSO4.7H2 O FROM RED-MUD

    Directory of Open Access Journals (Sweden)

    Nihat TINKILIÇ

    1996-02-01

    Full Text Available The red-mud obtained during the production of aluminium from bauxite as a by-product contains valuable materials such as Fe, Al, Na,V, Ti etc. In this study, red-mud was dissolved with H2 SO4 and converted to FeSO4.7H2 O by 86 % efficiency. The optimum converting conditions were found as heating for three hours at 170o C. The red-mud is not suitable for the production of pig iron because, it hasn't got enough iron contents(38.57 per cent Fe2 O3. We concluded that, the red-mud can be used in production of FeSO4.7H2 O.

  3. Alkalistable xylanase production by alkalitolerant Paenibacillus montaniterrae RMV1 isolated from red mud.

    Science.gov (United States)

    Arora, Amita; Krishna, Pankaj; Malik, Vinita; Reddy, M Sudhakara

    2014-10-01

    The alkalitolerant and xylanolytic bacterial strain (RMV1) isolated from red mud pond was identified as Paenibacillus montaniterrae based on both biochemical and 16S rDNA sequence analysis. The RMV1 bacterial isolate produced alkalistable and thermostable endoxylanase active over a broad range of pH (4.0-11.0) and temperature (20-100 °C), with optima at 50 °C and pH 9.0 with a T1/2 of 6.7 hours at 50 °C. This is the first report on the isolation of P. montaniterrae from bauxite residue with quite a high xylanase producing ability.

  4. Utilization of red mud in cement production: a review.

    Science.gov (United States)

    Liu, Xiaoming; Zhang, Na

    2011-10-01

    Red mud is a solid waste residue of the digestion of bauxite ores with caustic soda for alumina production. Its disposal remains a worldwide issue in terms of environmental concerns. During the past decades, extensive work has been done by a lot of researchers to develop various economic ways for the utilization of red mud. One of the economic ways is using red mud in cement production, which is also an efficient method for large-scale recycling of red mud. This paper provides a review on the utilization of red mud in cement production, and it clearly points out three directions for the use of red mud in cement production, namely the preparation of cement clinkers, production of composite cements as well as alkali-activated cements. In the present paper, the chemical and mineralogical characteristics of red mud are summarized, and the current progresses on these three directions are reviewed in detail.

  5. Invited Article: In situ comparison of passive radon-thoron discriminative monitors at subsurface workplaces in Hungary

    Science.gov (United States)

    Kávási, Norbert; Vigh, Tamás; Németh, Csaba; Ishikawa, Tetsuo; Omori, Yasutaka; Janik, Miroslaw; Yonehara, Hidenori

    2014-02-01

    During a one-year long measurement period, radon and thoron data obtained by two different passive radon-thoron discriminative monitors were compared at subsurface workplaces in Hungary, such as mines (bauxite and manganese ore) and caves (medical and touristic). These workplaces have special environmental conditions, such as, stable and high relative humidity (100%), relatively stable temperature (12°C-21°C), low or high wind speed (max. 2.4 m s-1) and low or elevated aerosol concentration (130-60 000 particles m-3). The measured radon and thoron concentrations fluctuated in a wide range among the different workplaces. The respective annual average radon concentrations and their standard deviations (in brackets) measured by the passive radon-thoron discriminative monitor with cellulose filter (CF) and the passive radon-thoron discriminative monitor with sponge filter (SF) were: 350(321) Bq m-3 and 550(497) Bq m-3 in the bauxite mine; 887(604) Bq m-3 and 1258(788) Bq m-3 in the manganese ore mine; 2510(2341) Bq m-3 and 3403(3075) Bq m-3 in the medical cave (Hospital Cave of Tapolca); and 6239(2057) Bq m-3 and 8512(1955) Bq m-3 in the touristic cave (Lake Cave of Tapolca). The respective average thoron concentrations and their standard deviation (in brackets) measured by CF and SF monitors were: 154(210) Bq m-3 and 161(148) Bq m-3 in the bauxite mine; 187(191) Bq m-3 and 117(147) Bq m-3 in the manganese-ore mine; 360(524) Bq m-3 and 371(789) Bq m-3 in the medical cave (Hospital Cave of Tapolca); and 1420(1184) Bq m-3 and 1462(3655) Bq m-3 in the touristic cave (Lake Cave of Tapolca). Under these circumstances, comparison of the radon data for the SF and CF monitors showed the former were consistently 51% higher in the bauxite mine, 38% higher in the manganese ore mine, and 34% higher in the caves. Consequently, correction is required on previously obtained radon data acquired by CF monitors at subsurface workplaces to gain comparable data for SF monitors. In the

  6. First Research on Marine and Nonmarine Sedimentary Sequences and Micropaleontologic Significance across Permian/Triassic Boundary in Iran (Isfahan and Abadeh)

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Abundant ichthyoid remains, conodonts and holothurians sclerites were recovered near the Permian/Triassic boundary from a section south of Isfahan. Recovered ichthyoid remains include shark micro teeth and scales. The ichthyolith material is similar to a Fasanian ichthyolith from the Zakazane area in the Slovak karst of the Western Carpathians, which represents a subspecies of Acodina triassica.Conodont species are mostly neogondolellids. This fauna indicates that the sedimentary environment was marine, while to the north of localities near Isfahan and Zagross, terrestrial deposition was dominant at that time. Aluminasilicate and kaolin are present in a continental unit in Dopolan refractory main (Shahid Nilchian mine) and a section south of Chahriseh Village, north of Isfahan. Pisolitie, ironstone facies and bauxite clay are common near the Permian/Triassic boundary in the Chahriseh region.

  7. Synthesis of N-decyl-1,3-diaminopropanes and its flotation properties on aluminium silicate minerals

    Institute of Scientific and Technical Information of China (English)

    胡岳华; 曹学锋; 李海普; 蒋玉仁; 杜平

    2003-01-01

    N-decyl-1, 3-diaminopropanes (DNs) were synthesized from alkyl-amine acrylonitrile at ambient pressure. With the synthesized DNs as collectors, the flotation of kaolinite, pyrophyllite and illite was conducted and the results were interpreted in terms of the structure-activity relationship. The DNs are found to be more effective collectors than dodecyl amine, exhibiting the highest recovery over a pH range of 4-6. Among the DNs examined, DN12 shows the highest flotation efficiency. The flotation mechanisms were explained in view of the structures of reagents and aluminium silicate minerals. It is demonstrated that DNs can become new selective collectors for reverse floatation to remove aluminium silicate minerals from bauxite.

  8. Aluminium leaching from red mud by filamentous fungi.

    Science.gov (United States)

    Urík, Martin; Bujdoš, Marek; Milová-Žiaková, Barbora; Mikušová, Petra; Slovák, Marek; Matúš, Peter

    2015-11-01

    This contribution investigates the efficient and environmentally friendly aluminium leaching from red mud (bauxite residue) by 17 species of filamentous fungi. Bioleaching experiments were examined in batch cultures with the red mud in static, 7-day cultivation. The most efficient fungal strains in aluminium bioleaching were Penicillium crustosum G-140 and Aspergillus niger G-10. The A. niger G-10 strain was capable to extract up to approximately 141 mg·L(-1) of aluminium from 0.2 g dry weight red mud. Chemical leaching with organic acids mixture, prepared according to A. niger G-10 strain's respective fungal excretion during cultivation, proved that organic acids significantly contribute to aluminium solubilization from red mud.

  9. Study of CO2 cyclic absorption stability of CaO-based sorbents derived from lime mud purified by sucrose method.

    Science.gov (United States)

    Ma, AiHua; Jia, QingMing; Su, HongYing; Zhi, YunFei; Tian, Na; Wu, Jing; Shan, ShaoYun

    2016-02-01

    Using lime mud (LM) purified by sucrose method, derived from paper-making industry, as calcium precursor, and using mineral rejects-bauxite-tailings (BTs) from aluminum production as dopant, the CaO-based sorbents for high-temperature CO2 capture were prepared. Effects of BTs content, precalcining time, and temperature on CO2 cyclic absorption stability were illustrated. The cyclic carbonation behavior was investigated in a thermogravimetric analyzer (TGA). Phase composition and morphologies were analyzed by XRD and SEM. The results reflected that the as-synthesized CaO-based sorbent doped with 10 wt% BTs showed a superior CO2 cyclic absorption-desorption conversion during multiple cycles, with conversion being >38 % after 50 cycles. Occurrence of Ca12Al14O33 phase during precalcination was probably responsible for the excellent CO2 cyclic stability.

  10. Implementation of industrial waste ferrochrome slag in conventional and low cement castables: Effect of microsilica addition

    Directory of Open Access Journals (Sweden)

    Pattem Hemanth Kumar

    2014-06-01

    Samples with decreasing cement content 15–05 wt.% were formulated in combination of both slag and calcined bauxite as matrix components. Effects of varying 0–10 wt.% microsilica as a micro-fine additive in these castables were investigated in this work. Pore filling properties of microsilica improved apparent porosity and bulk density. Phase analysis through X-ray diffraction techniques demonstrates successful formation of spinel and mullite crystalline phases. Mechanical behavior was evaluated through cold crushing strength and residual cold crushing strength after five consecutive water quenching cycles. Scanning electron microscopy measurements were carried out in order to better understand the packing density and reaction mechanisms of fired castables. Slag containing castables portrays good thermal properties such as thermal shock resistance, permanent linear change and pyrometric cone equivalent.

  11. Utilization of red mud for the purification of waste waters from nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Luka, Mikelic; Visnja, Orescanin; Stipe, Lulic [Rudjer Boskovic Institute, Lab. for radioecology, Zagreb (Croatia)

    2006-07-01

    Sorption of the radionuclides and heavy metals from low level liquid radioactive waste on the coagulant produced from bauxite waste (red mud and waste base) was presented. Research was conducted on composite annual samples of waste water collected in the Waste Monitor Tank (W.M.T.) from Kro Nuclear Power Plant during each month. Activities of radionuclide in W.M.T. were measured before and after purification using high purity germanium detector. Also, elemental concentrations in W.M.T. before and after purification were measured by source excited energy dispersive X-ray fluorescence (E.D.X.R.F.). It has been showed that activated red mud is excellent purification agent for the removal of radionuclides present in low level liquid radioactive waste. Removal efficiency was 100% for the radionuclides {sup 58}Co and {sup 60}Co 100%, and over 60% for {sup 134}Cs and {sup 137}Cs. (authors)

  12. Analysis of Proppant Hydraulic Fracturing in a Sand Oil Reservoir in Southwest of Iran

    Directory of Open Access Journals (Sweden)

    Reza Masoomi

    2015-10-01

    Full Text Available Hydraulic fracturing is one way to increase the productivity of oil and gas wells. One of the most fundamental successes of hydraulic fracturing operation is selecting the proper size and type of proppants which are used during the process. The aim of this study is optimizing the type and size of used propant in hydraulic fracturing operation in a sand oil reservoir in southwest of Iran. In this study sand and ceramic (sintered bauxite have been considered as proppant type. Also the various types of resin-coated sand and resin-coated ceramic have been considered. Then the various scenarios have been designed to optimize the size and type of proppant used in hydraulic fracturing in a sand oil reservoir in southwest of Iran. Also in this study increasing the cumulative oil recovery in fractured and Non-fractured wells in a sand oil reservoir in southwest of Iran have been investigated.

  13. Paleogeography of the Berriasian-Barremian ages of the Early Cretaceous

    Energy Technology Data Exchange (ETDEWEB)

    Zharkov, M.A.; Murdmaa, I.O.; Filatova, N.I. [Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Geology

    1998-01-01

    Global lithologic-paleogeographic maps were compiled for the Berriasian, Valanginian, Hauterivian, and Barremain ages of the Early Cretaceous. Main features of paleogeography, sedimentation environments in oceans, regularities in distribution of paleogeographic environments in continental margins, spatial position of arid and humid sedimentation settings in continents, and position of latitudinal climate belts of the Neocomian time are considered. Five latitudinal climatic belts of the Neocomian time corresponded to the northern circumpolar humid zone with coal deposits, the northern mid-latitudinal humid zone with coal-bauxite-kaolinite deposits, the inter-subtropical arid zone with evaporites, the southern mid-latitudinal humid zone with coal-kaolinite deposits, and the southern humid zone with coal-bearing sequences.

  14. Slurry pipeline design approach

    Energy Technology Data Exchange (ETDEWEB)

    Betinol, Roy; Navarro R, Luis [Brass Chile S.A., Santiago (Chile)

    2009-12-19

    Compared to other engineering technologies, the design of a commercial long distance Slurry Pipeline design is a relatively new engineering concept which gained more recognition in the mid 1960 's. Slurry pipeline was first introduced to reduce cost in transporting coal to power generating units. Since then this technology has caught-up worldwide to transport other minerals such as limestone, copper, zinc and iron. In South America, the use of pipeline is commonly practiced in the transport of Copper (Chile, Peru and Argentina), Iron (Chile and Brazil), Zinc (Peru) and Bauxite (Brazil). As more mining operations expand and new mine facilities are opened, the design of the long distance slurry pipeline will continuously present a commercially viable option. The intent of this paper is to present the design process and discuss any new techniques and approach used today to ensure a better, safer and economical slurry pipeline. (author)

  15. Reminiscences From a Career in Geomicrobiology

    Science.gov (United States)

    Ehrlich, Henry L.

    2012-05-01

    This is a memoir relating how the author became a geomicrobiologist and how he practiced his specialty. Born in Germany and receiving his early schooling in Berlin, he completed his secondary education, followed by college and graduate school training, after emigration to the United States in 1940. After attaining a PhD degree in 1951, he spent his entire professional career as a faculty member of the Department of Biology at Rensselaer Polytechnic Institute (RPI) in Troy, New York. He was introduced to geomicrobiology in 1959 by a question from a colleague in the Department of Geology at RPI concerning the recent discovery of acidophilic iron-oxidizing, autotrophic bacteria in acid coal mine drainage. This led him to investigate bacterial interaction with metal sulfides, Mn(II) and Mn(IV) on land and in the sea, chromate, and bauxite; to teach a course in geomicrobiology; and to write a textbook on the subject, first published in 1981.

  16. Interaction of mining activities and aquatic environment: A review from Greek mine sites.

    Science.gov (United States)

    Vasileiou, Eleni; Kallioras, Andreas

    2016-04-01

    In Greece a significant amount of mineral and ore deposits have been recorded accompanied by large industrial interest and a long mining history. Today many active and/or abandoned mine sites are scattered within the country; while mining activities take place in different sites for exploiting various deposits (clay, limestone, slate, gypsum, kaolin, mixed sulphide ores (lead, zinc, olivine, pozzolan, quartz lignite, nickel, magnesite, aluminum, bauxite, gold, marbles etc). The most prominent recent ones are: (i) the lignite exploitation that is extended in the area of Ptolemais (Western Macedonia) and Megalopolis (Central Peloponnese); and (ii) the major bauxite deposits located in central Greece within the Parnassos-Ghiona geotectonic zone and on Euboea Island. In the latter area, significant ores of magnesite were exploited and mixed sulphide ores. Centuries of intensive mining exploitation and metallurgical treatment of lead-silver deposits in Greece, have also resulted in significant abandoned sites, such as the one in Lavrion. Mining activities in Lavrio, were initiated in ancient times and continued until the 1980s, resulting in the production of significant waste stockpiles deposited in the area, crucial for the local water resources. Ιn many mining sites, environmental pressures are also recorded after the mine closure to the aquatic environment, as the surface waters flow through waste dump areas and contaminated soils. This paper aims to the geospatial visualization of the mining activities in Greece, in connection to their negative (surface- and/or ground-water pollution; overpumping due to extensive dewatering practices) or positive (enhanced groundwater recharge; pit lakes, improvement of water budget in the catchment scale) impacts on local water resources.

  17. Recovery of value-added products from red mud and foundry bag-house dust

    Science.gov (United States)

    Hammond, Keegan

    "Waste is wasted if you waste it, otherwise it is a resource. Resource is wasted if you ignore it and do not conserve it with holistic best practices and reduce societal costs. Resource is for the transformation of people and society." Red mud is a worldwide problem with reserves in the hundreds of millions of tons and tens of millions of tons being added annually. Currently there is not an effective way to deal with this byproduct of the Bayer Process, the primary means of refining bauxite ore in order to provide alumina. This alumina is then treated by electrolysis using the Hall-Heroult process to produce elemental aluminum. The resulting mud is a mixture of solid and metallic oxides, and has proven to be a great disposal problem. This disposal problem is compounded by the fact that the typical bauxite processing plant produces up to three times as much red mud as alumina. Current practice of disposal is to store red mud in retention ponds until an economical fix can be discovered. The danger associated with this current method of storage is immense to the surrounding communities and environment, thus the interest from the Center for Resource Recovery and Recycling (CR3). The purpose of this document is to explain one way to remove the value added materials, primarily iron, from the Jamaican red mud using both pyrometallurgical and hydrometallurgical approaches. In the beginning, soda ash and carbon roasting were completed simultaneously at 800°C. This type of roasting produced results that were unacceptable. After the soda ash roast was completed independently of carbon roasting, a water wash produced results that separations of alumina at 90%, Iron at 99%, calcium at 99%, titanium t 100%, and sodium by 74%. Smelting produced separations of 97% for alumina, 99% for iron, 87% for sodium, 94% for calcium and 72% for titanium.

  18. Water/rock interactions and mass transport within a thermal gradient Application to the confinement of high level nuclear waste; Interactions solide/solution et transferts de matiere dans un gradient de temperature. Application au confinement des dechets nucleaires de haute-activite

    Energy Technology Data Exchange (ETDEWEB)

    Poinssot, Ch. [CEA Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Entreposage et de Stockage des Dechets]|[Ecole Normale Superieure, 92 - Fontenay-aux-Roses (France). Laboratoire de Geologie

    1998-12-31

    The initial stage of a high level nuclear waste disposal will be characterised by a large heat release within the near-field environment of the canisters. This heat flux caused by radioactive decay will lead to an increase of temperature and a subsequent thermal gradient between the `hot` canisters and the `cold`geological medium. In addition, this thermal gradient will decrease with time due to the heat decay although it could last hundred years. What will be the consequences of such a thermal field varying both on space and time for the alteration of the different constituents of the near field environment. In particular, what could be the effects on the radionuclides migration in the accidental case of an early breach of a canister during the thermal stage? This study brings significant answers to these questions in the light of a performance assessment study. This work is supported by a triple methodological approach involving experimental studies, modelling calculations and a natural analogues study. This complete work demonstrates that a thermal gradient leads to a large re-distribution of elements within the system: some elements are incorporated in the solid phases of the hot end (Si, Zr, Ca) whereas some others are in those of the cold end (Fe, Al, Zn). The confrontation of the results of very simple experiments with the results of a model built on equilibrium thermodynamics allow us to evidence the probable mechanisms causing this mass transport: out-of-equilibrium thermodiffusion processes coupled to irreversible precipitation. Moreover, the effects of the variation of temperatures with time is studied by the way of a natural system which underwent a similar temperature evolution as a disposal and which was initially rich in uranium: the Jurassic Alpine bauxites. In addition, part of the initial bauxite escaped this temperature transformations due to their incorporation in outer thrusting nappes. They are used as a reference. (author)

  19. Relief inversion in the geomorphological evolution of sub-Saharan West Africa

    Science.gov (United States)

    Butt, C. R. M.; Bristow, A. P. J.

    2013-03-01

    The geomorphology of much of sub-Saharan West Africa is dominated by the presence of plateaux and plains with ferruginous and, locally, aluminous (bauxitic) duricrusts. The plateaux occur at different elevations and have been correlated as two or more palaeosurfaces across much of the region. The duricrusts have generally been considered to be residual, formed by conformable erosion and chemical wasting of immediately underlying bedrock. This concept has been central to interpretations as diverse as the formation and evolution of the landscape and the development of geochemical exploration models. Recent regolith landform mapping, field observations and experience from mineral exploration in southern Mali and Burkina Faso, however, demonstrate that the duricrusts are mainly ferricretes, i.e., Fe oxide-cemented sediments. These observations require a re-interpretation of the geomorphological evolution of the region during the Cenozoic. The landscape has evolved by several cycles of weathering and erosion-deposition, triggered by climatic, tectonic or other environmental changes. It is proposed that an initial bauxitic/lateritic regolith was partly eroded following uplift and/or a change to a more arid climate, and that the detritus, rather than being removed, was deposited on slopes and valleys. During a subsequent humid period of lateritic weathering, Fe oxide cementation of this detritus formed ferricrete. Dehydration and hardening of the ferricrete after further uplift or aridity increased its resistance to erosion, resulting in relief inversion, with the detritus, in turn, being deposited downslope. This too has been weathered and cemented, to form a younger ferricrete. The occurrence of ferricrete landforms in adjacent countries, noted by field observation and inferred from satellite imagery, demonstrates that relief inversion is a very widespread and important phenomenon in southern Mali, Burkina Faso and adjacent countries in semi-arid West Africa.

  20. Chemical and physical erosion rhythms of the West African Cenozoic morphogenesis: The 39Ar-40Ar dating of supergene K-Mn oxides

    Science.gov (United States)

    Beauvais, Anicet; Ruffet, Gilles; HéNocque, Olivier; Colin, Fabrice

    2008-12-01

    Chemical weathering and mechanical erosion are first-order processes of long-term tropical morphogenesis, which is still poorly deciphered for lack of time constraints. We address this issue by laser probe 39Ar-40Ar dating of generations of cryptomelane [K1-2Mn8O16, nH2O] from the manganese ore deposit of Tambao in northern Burkina Faso. This Mn deposit results from the supergene weathering of carbonate and silicate Mn protores underneath lateritic palaeolandsurfaces. It consists of an upper cryptomelane-rich domain and a lower domain where pyrolusite (β-MnO2) is the dominant Mn oxide. The oldest 39Ar-40Ar ages (59-45 Ma) are obtained on surface outcrops while the youngest ones characterize deep oxidation fronts (3.4-2.9 Ma). Apparent correlations of 39Ar-40Ar age groups with δ18O and eustatic curves allow definition of the different stages of morphogenesis. Paleocene-Eocene ages (59-45 Ma) bracket a greenhouse period propitious to bauxitic weathering. The lack of significant ages between ˜45 and 29 Ma characterizes a period dominated by mechanical erosion, during which detrital sediments, including lateritic materials, were accumulated in intracratonic basins allowing the exhumation of a new lateritic landsurface. Two major weathering periods separated by a second erosion episode (24-18 Ma) are also depicted at the end of Oligocene (29-24 Ma) and lower to mid-Miocene (18-11.5 Ma) in the upper domain, during which newly shaped land surfaces conspicuously weathered. The shorter-weathering and erosion episodes recorded in the lower domain from ˜18 to ˜2.9 Ma led to the final geomorphic changes that were conducive to the formation of glacis. The preservation of old cryptomelane (59-45 Ma) in the upper part of the ore deposit indicates a Cenozoic denudation limited to the erosion of previous bauxites, and partly, of ferricretes.

  1. Technology optimization for manufacturing biodegradable mulch using soybean straw fiber%大豆秸秆纤维制造可降解地膜工艺参数优化

    Institute of Scientific and Technical Information of China (English)

    李丽霞; 纪文义※; 陈海涛; 周成

    2013-01-01

      A mount of straw residue left in the field is able to raise the environmental pollution and resource waste. Utilization of the straw resource enables to resolve these problems, promote the economic growth, open the new industries and increase employment. The manufacture of biodegradable film raises the high utilization value of soybean straw resources. The biodegradable film is low cost and friend environment, which can meet the requirements of covering and cultivation. The method applied five factors and five levels 1/2 quadratic regression orthogonal rotation center. Grammage, mixing ratio, rosin, bauxite, and wet strength agent were influencing factors. Dry tensile strength, wet tensile strength were objective functions. The measurement of dry tensile strength was referenced to the GB/T453-1989 and the measurement of wet tensile strength was referenced to the GB/T465.2-1989. This paper analyzed the effect of factors on the dry tensile strength and wet tensile strength, the rate of factors on objective function, and the optimal technology parameters of soybean straw fiber for manufacturing biodegradable mulch. Through the analysis of the effect of factors on function, the models of dry tensile strength and wet tensile strength were built and the models were significantly different. The rank of effect of every factor on functions was judged by the F value. The results showed that 1)The rank of effect of five factors on dry tensile strength:KP mixture ratio, grammage, wet strength agent, rosin and bauxite;2)The rank of effect of five factors on the wet tensile:KP mixing ratio, grammage, wet strength agent, bauxite and rosin;3)in the conditions when grammage of 50-110 g/m2, mixing ratio of 0-50%, wet strength agent of 1.2%-2.0%, rosin of 0.3%-1.5%, bauxite of 1%-5%, optimal technology parameters of soybean straw fiber manufacturing biodegradable film were grammage of 92-110 g/m2, mixing ratio of 23.3%-30%, wet strength agent of 1.2%, rosin of 0.3%, bauxite of

  2. Development Status of Mineral Resources in Five Countries of the Indochina Peninsula and Investment Preferences for China%中南半岛五国矿产资源开发现状及中国的投资取向

    Institute of Scientific and Technical Information of China (English)

    程新; 沈镭; 高天明

    2011-01-01

    The Indochina Peninsula includes Vietnam, Laos, Cambodia, Myanmar, and Thailand. This paper first outlines resource situations in the Indochina Peninsula, analyzes the distribution of advantageous mineral resources and their development situations in the five countries. Thailand is abundant in antimony, potassium, and tin resources. The reserve of Thai antimony was more than 420 thousand tons in 2009, accounting for 20% of the world’s total reserve. It is mainly distributed in northern Thailand, such as LamPang, Phrae, and Chiang Mai Provinces. Its production in 2008 was 422 ton. Potassium is also rich in Thailand, and has not been mined at large scales. Tin and iron ore were not well exploited, either. Their productions mainly rely on imports. Coal, phosphate, and bauxite are rich in Vietnam. Coal is primarily anthracite and lignite; anthracite is distributed in C?m Ph?, thành ph? H? Long, Qu?ng Ninh Provinces, northeast Vietnam. Lignite is distributed in the Red River basin; the coal reserve in the area is more than 200 billion ton. Bauxite is Vietnam’s dominant mineral, and its reserve is huge. The reserve of phosphate is more than 1.4 billion ton. Due to backward mining technology, its mineral resources were not effectively developed and utilized. Potassium is abundant in the Vientiane plain, and its prospective reserve is more than 10 billion ton. Copper, bauxite, and tin reserves are more than other mining resources in Laos. Cambodia and Myanmar are rich in oil, non-ferrous metals, and gem. The degree of mineral resources development in these five counties is very low, even ranking one of the most undeveloped areas in the world. We discussed their mining investment environment in this region. All the counties have special departments for mining management, enact related laws to protect the interests of the owner, and provide some preferential policies to attract mining investment. We suggest that every country should optimize their mining

  3. AGRONOMIC EFFICIENCY OF NATURAL PHOSPHATES AND THEIR INFLUENCE ON SOIL AVAILABLE PHOSPHORUS ON TWO CERRADO SOILS EFICIÊNCIA AGRONÔMICA DE FOSFATOS NATURAIS E SUA INFLUÊNCIA NO FÓSFORO DISPONÍVEL EM DOIS SOLOS DE CERRADO

    Directory of Open Access Journals (Sweden)

    Huberto José Kliemann

    2007-09-01

    Full Text Available

    To evaluate the agronomic efficiency of natural phosphates soybean was grown in two oxisols under cerrado vegetation, using apatites (Araxá, Patos de Minas, Tapira, Abaeté, and Catalão, phosphoric bauxites (Pirocaua and Phospal, Gafsa hyperphosphate, nd IPT thermophosphate, using triple superphosphate as a control. he agronomic efficiency indexes found were: a apatites - Araxá nd Abaeté, 27%; Patos de Minas, 13%; Tapira, 5%, and Catalão, %; b phosphoric bauxites - Pirocaua, 41% and Phospal, 50%; c hermophosphate IPT, 97% and hyperphosphate of Gafsa, 102%. he acid extractor Mehclich-1 overestimates available P when nsoluble apatites are applied to soils. Bray-1 and Bray-2 extractors referably solubilize the aluminum phosphates from phosphoric auxites. Critical levels of soil available phosphorus are suitably stimated by Bray-1 extractant when apatitic phosphates and by ehlich-1 extractant phosphoric bauxites are applied.

    KEY-WORDS: Oxisols; soybeans; phosphates sources; chemical extractors; soybean.

    Conduziram-se experimentos de avaliação de fosfatos naturais em latossolo vermelho-escuro distrófico (textura média e latossolo roxo distrófico (textura argilosa, fase cerrado, no Estado de Goiás. Usaram-se a soja como planta-teste, curvas de resposta com superfosfato triplo (SFT como padrão e como fontes de fósforo as apatitas de Araxá, Patos de Minas, Tapira, Abaeté e Catalão, as bauxitas fosfóricas de Pirocaua (Maranhão e Phospal (Senegal, o hiperfosfato de Gafsa e o termofosfato IPT. Obtiveram-se os seguintes índices de eficiência agronômica (IEA: a apatitas – Abaeté e Araxá: 27%; Patos de Minas: 13%; Tapira: 5%; e Catalão: 2%; b termofosfato IPT: 97% e o hiperfosfato reativo de Gafsa, 102%; c bauxitas de Pirocaua, 41% e Phospal: 50%. Os extratores Mehlich-1, Bray-1

  4. Suriname.

    Science.gov (United States)

    1984-10-01

    A summary description of Suriname's population, geography, history, government, economy, and foreign relations is provided. Suriname, a tropical country, situated on the northern coast of South America, consists of a coastal zone, a central forested region, and a sparsely populated southern savanna zone. Most of the country's approximately 400,000 inhabitants live in the coastal zone, which contains most of the country's agricultural land. The population is ethnically diverse and is 37% Hindustani, 31% Creole, 15.3% Javanese, 10.3% Bush Negro, 2.7% Amerindian, 2.7% Chinese, and 1% European. European settlement began in 1651. Between 1667-1815 the country was rule alternately by the Netherlands and Great Britian. In 1975 Suriname obtained independence from the Netherlands and was governed as a parliamentary democracy between 1975-80. In 1980 the government was overthrown by a military coup, and the constitution was suspended. Although there have been several changes in government structure and leadership since 1980, the country continues to be ruled by military decree. In 1984 a Supreme Council, composed of representives of the military, labor federations, and business organizations and chaired by the army commander, Desire D. Bouterse, was established. Although ultimate authority resides in the commander and in the military, there is also a Council of Ministers, composed of labor and business leaders and headed by the Minister-President, L.F. Ramdat-Misier. The government exerts considerable control over the news media. During the colonial era, a plantation economy, based on the production of cocoa, coffee, sugar, and cotton, was established. The system was supported first by African slave labor, and then by Asian contract agricultural laborers. Suriname's current economy is based largely on the mining, processing and exporting of bauxite. The bauxite industry is dominated by the Suriname Aluminum Company, a subsidiary of the Aluminum Company of America, and by the

  5. The wettability of water treatment filter media measured by dynamic osmotic pressure%基于动态渗透压力法的水处理滤料的润湿性研究

    Institute of Scientific and Technical Information of China (English)

    董会平; 何应东

    2012-01-01

    Filtration is a typical tertiary treatment method for oil-bearing water, The kinds of filter media and its surface nature have an important influence on treatment result in the filtration unit operation. The wettability of filter media is the most important influence factor. The lipophilic and hydrophilic properties of anthracite, activated zeolite, bauxite ceramic, magnetite and zeolite were studied by using dynamic osmotic Pressure method, which is based on the principle of Washburn equation. When filter media size distribution are 20~ 30 meshes and 30 40 meshes, using dynamic osmotic pressure method to study wettability of the filter media is feasible and the experiment results is precise and credible. When the particle size distribution are between 20meshes and 30 meshes, the LHR values of anthracite, activated zeolite, bauxite ceramic, magnetite and zeolite are 2.51,1.77,1.75,1.32 and 1.26 respectively, when the particle size distribution are between 30meshes and 40 meshes, the LHR values of activated zeolite, bauxite ceramic and magnetite are 2.28,2.27 and 0.86 respectively.%过滤是一种常用的含油废水深度处理方法,在过滤单元操作中,滤料的品种对处理效果有重要影响,其中滤料的润湿性是最重要的影响因素之一。本论文以Washburn方程为原理,用动态渗透压力法研究了无烟煤、活化沸石、铝矾土陶瓷、磁铁矿及沸石5中滤料的亲油亲水润湿性,当滤料粒径范围分别在20~30目和30~40目之间时,实验结果较为准确可靠。结果表明粒径范围在20~30目时,用动态渗透压力法测得的无烟煤、活化沸石、铝矾土陶瓷、磁铁矿及沸石滤料的LHR值依次为2.21、1.77、1.75、1.32和1.26;粒径范围在30~40目时,用动态渗透压力法测得的活化沸石、铝矾土陶瓷及磁铁矿滤料的LHR值依次为2.28、2.27和0.86。

  6. NOVAS APLICAÇÕES DE SISTEMAS SFE "HOME MADE": III. ENERGIA QUÍMICA E ELÉTRICA

    Directory of Open Access Journals (Sweden)

    Fernando M. LANÇAS

    1997-12-01

    Full Text Available Este trabalho apresenta três aplicações da SFE com diferentes fluídos supercríticos, matrizes e sistemas de extração. Um sistema estático "home made" foi utilizado na pesquisa de fontes alternativas de insumos químicos e energéticos tais como o bagaço de cana-de-açucar e o carvão mineral. Foram usados, respectivamente, o etanol (sem e com catalisador e o tolueno como fluídos extratores e hidrogênio como gás de pressurização. Na extração dos contaminantes do óleo mineral adsorvidos em bauxita, foi utilizado o dióxido de carbono como fluído extrator em um sistema "home made"/dinâmico. Estudos visando a maximização do rendimento de alguns dos processos também foram realizados, utilizando o planejamento fatorial e a metodologia da superfície de resposta. Os produtos de maior interesse neste trabalho (fração de resinas, obtidos do processo de extração do bagaço de cana-de-açucar e aqueles contaminantes do óleo isolante adsorvidos em bauxita extraídos com fluídos supercríticos foram caracterizados usando cromatografia gasosa de alta resolução com detector de ionização de chama (CGAR - DIC e cromatografia gasosa de alta resolução com detector seletivo de massas (CGAR - EM após fracionamento por cromatografia líquida preparativa em 8 frações distintas.This work presents three aplications of SFE with different supercritical fluids, samples and extraction systems. A home made static system was utilized in the search for alternative chemicals and energetics resources such as sugar cane bagasse and mineral coal. Ethanol (with and without catalyst and toluene were used, respectively ,as extraction fluids and hydrogen as pressurization gas. The adsorbed contaminants of mineral oil in bauxite were also extracted with carbon dioxide as extractor fluid in a home made dinamical system. Maximization of yields in some processes was studied using factorial design and response surface methodologies. The products

  7. Preparation of Cristobalite-based Ceramics Using the Discarded Quartz Crucible%废弃石英坩埚资源化制备方石英质瓷

    Institute of Scientific and Technical Information of China (English)

    孙健; 李家科; 王艳香; 朱海翔

    2016-01-01

    Cristobalite-based ceramics were prepared using the discarded quartz crucible , kaolin, feldspar and bauxite as raw materials .The effects of batch formula and firing temperature on phase composition , microstructure , coefficient of thermal expansion and mechanical performances of cristobalite-based ceramics were investigated by XRD , SEM, thermal dilatometer and material testing machine .The results show that cristobalite-based ceramics with good mechanical performances are obtained when discarded quartz crucible 40%, kaolin 40%, feldspar 15% and bauxite 5% at 1300 ℃ for 30 min .Bending strength and coefficient of thermal expansion of cristobalite-based ceramic are 76.45 MPa and 7.16 × 10 -6℃-1 ( RT~600 ℃) ,respectively .And thermal shock resistance (△T ) is above 180 ℃.%以废弃石英坩埚、苏州土、长石和铝矾土等为原料制备方石英质瓷。采用XRD、SEM、热膨胀仪和材料试验机等测试方法,研究了配方组成和烧成温度对方石英质瓷的物相组成、微观形貌和机械性能影响规律。结果表明:当配料配方中废弃石英坩埚40%、苏州土40%、钾长石15%和铝矾土5%,在烧成温度1300℃、保温时间30 min条件下,可以获得机械性能较佳的方石英质瓷,其弯曲强度为76.45 MPa,热稳定性△T ≥180℃,热膨胀系数为7.16×10-6℃-1( RT~600℃)。

  8. 套管跟进与绳索取心组合钻探技术的应用%Application of the Combined Drilling Technology of Drilling with Casing and Wire-line Coring

    Institute of Scientific and Technical Information of China (English)

    胥虹

    2014-01-01

    针对贵州省清镇市犁倭乡红花寨、白浪坝铝土矿破碎、漏孔、坍塌掉块的灰岩地层,采用了套管跟进与绳索取心组合钻探技术,克服了常规钻探技术方法钻进困难的问题,顺利完成了ZK3369孔钻探任务,取得了良好的效果。在分析施工难点的基础上,介绍了在破碎、漏失、坍塌掉快地层中套管跟进与绳索取心组合钻探技术施工工艺。%According to the broken, leaking, clasping and block falling limestone formations of the bauxite in Guizhou, the combined drilling technology of drilling with casing and wire-line coring was used to overcome the difficulties of conventional drilling methods, ZK3369 hole drilling was successfully completed with good result.On the basis of the analysis on the con-struction difficulties, the paper introduces the combined drilling technology of drilling with casing and wire-line coring in the broken, leaking, clasping and block falling formations.

  9. Landscape matrix mediates occupancy dynamics of Neotropical avian insectivores

    Science.gov (United States)

    Kennedy, Christina M.; Campbell Grant, Evan H.; Neel, Maile C.; Fagan, William F.; Marpa, Peter P.

    2011-01-01

    In addition to patch-level attributes (i.e., area and isolation), the nature of land cover between habitat patches (the matrix) may drive colonization and extinction dynamics in fragmented landscapes. Despite a long-standing recognition of matrix effects in fragmented systems, an understanding of the relative impacts of different types of land cover on patterns and dynamics of species occurrence remains limited. We employed multi-season occupancy models to determine the relative influence of patch area, patch isolation, within-patch vegetation structure, and landscape matrix on occupancy dynamics of nine Neotropical nsectivorous birds in 99 forest patches embedded in four matrix types (agriculture, suburban evelopment, bauxite mining, and forest) in central Jamaica. We found that within-patch vegetation structure and the matrix type between patches were more important than patch area and patch isolation in determining local colonization and local extinction probabilities, and that the effects of patch area, isolation, and vegetation structure on occupancy dynamics tended to be matrix and species dependent. Across the avian community, the landscape matrix influenced local extinction more than local colonization, indicating that extinction processes, rather than movement, likely drive interspecific differences in occupancy dynamics. These findings lend crucial empirical support to the hypothesis that species occupancy dynamics in fragmented systems may depend greatly upon the landscape context.

  10. Morphological description of collateral branches from the abdominal aorta of lesser anteater (Tamandua tetradactyla

    Directory of Open Access Journals (Sweden)

    Breno Costa Macedo

    2013-03-01

    Full Text Available Tamandua tetradactyla, Xenarthra, is a native species from South America which, due to the few number of studies on its biology, still has many unknown aspects in its morphology. Taking into account the importance of morphological data for various studies, this paper aimed to elucidate the branching of the abdominal aorta in this species to foster the development of further studies. To do this, 4 specimens were used, 2 male and 2 female, all young, from the Bauxite Mine – Paragominas, Para, Brazil, donated after death due to running over to the Animal Morphology Research Laboratory (LaPMA of Universidade Federal Rural da Amazonia (UFRA. The arterial system was filled with contrasted latex and the animals were fixed in a formaldehyde solution (10%, and then dissected, in order to evidence the abdominal aorta and its collateral branches. The parietal branches consisted of 1 pair of caudal phrenic arteries, 2 pairs of intercostal arteries, and 3 pairs of lumbar arteries. Among the visceral branches, stood out: celiac artery; cranial mesenteric artery; adrenal arteries; renal arteries; caudal mesenteric artery; and external, internal, and median sacral iliac arteries, formed from the final portion of the abdominal aorta. Testicular and ovarian arteries originated from the renal arteries, differing from that described in various species.

  11. 山东省石炭二叠纪沉积岩建造与成矿作用%Formation and Mineralization of Carboniferous-Permian Sedimentary Rocksin Shandong Province

    Institute of Scientific and Technical Information of China (English)

    梁太涛; 李洪奎; 耿科; 禚传源; 王峰; 汤启云

    2014-01-01

    Carboniferous Permian is major coal forming period in Shandong province.Bauxite and hard clay deposit have been formed at the same time.Regarding basic sequence of sedimentary rock as basic principle and sedimentary facies as classification basis,coordinated sedimentary cycle division and lithostratigraphic unit division principle,Carboniferous Permian in Shandong province can be divided into 5 sedimentary rock formations,its characteristics have been introduced,and the relationship between Carboniferous Permian sedimentary rock formation and mineralization has been described.%石炭二叠纪是山东省主要成煤时期,同时期形成的矿产还有铝土矿及硬质粘土矿。根据以沉积岩基本层序为基础原则、以沉积相划分为依据原则、与沉积旋回划分相一致原则、与组级岩石地层单位划分相协调原则等沉积岩建造类型划分原则,将山东省石炭二叠系划分为5个沉积岩建造,介绍了其特征,并阐述了石炭二叠纪沉积岩建造与成矿作用的关系。

  12. Thermal decomposition behaviour of polyacrylamidomethyltrimethyl ammonium chloride in red mud separation process

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to provide references for selecting highly efficient red mud flocculants,the behaviour of polyacrylamidomethyltrimethyl ammonium chloride (PATAC) in red mud separation process was investigated.PATAC was employed as a flocculant for red mud separation from the caustic aluminate liquor at 95 ℃.The used red mud was generated from Chinese diaspore bauxite in Bayer process of alumina production.And the changes of PATAC before or after being treated in caustic solution at 95 ℃ were studied by thermogravimetry (TG) and Fourier transform infrared (FTIR) spectral analysis.The results show that PATAC fails in effectively flocculating red mud and PATAC is readily converted to a quaternary ammonium hydroxide (PATAH) in caustic solution.PATAH can be decomposed to a new polymer (HPATAH) even at 95 ℃.Furthermore,there is an intramolecular hydrogen bond formed in the HPATAH polymer chain with two functional groups of -CH2-OH and -CONH2.Therefore,the poor flocculation property of PATAC for red mud separation can be attributed to the thermal decomposition of PATAC in the caustic red mud slurry at 95 ℃ and the formation of intramolecular hydrogen bond in the polymer chain of HPATAH during the thermal decomposition,which causes the absorbable functional groups of PATAC to decrease greatly.

  13. MINERAÇÃO E CAMPESINATO NO MUNiCípIO DE JURUTI/PA, BRASIL

    Directory of Open Access Journals (Sweden)

    João Santos Nahum

    2012-01-01

    Full Text Available We focus on a chapter of the agrarian issue in the Amazon, characterized by territorial disputes between a mining company and the smallholders in the city of Juruti (PA. Here, for the first time in the history of large-scale projects in the Amazon, smallholders, especially riparian farmers and extractivists, supported by outreach from the Catholic Church'sPastoral Land Commission (CPT, the rural workers' union, and political and community leaders, organized and built a coalition representing their interests and protested against a mining project. The coalition collectively managed supporters' land rights, their right to a percentage of profits from the mining of bauxite, as well as using it directly. We raise secondary data, which supported our analysis of geographical focus, from literature review and consultation sites. The information and primary data were collected and systematized through field work, where, as the Brazilian saying goes, we put "the dirt of the place under our fingernails" and thus describe the processes surveyed. In the first part of the paper we describe the conditions and possibilities that allowed the mining activities in Juruti. In the second part we analyze the territorial disputes between ALCOA (Aluminium Company of America and the smallholders, organized in ACORJUVE (Community Association of the Gleba Old Juruti Region. Then we present some final considerations, without the worry of completing the analysis.

  14. Utilization of preparation refuse in the Federal Republic of Germany

    Energy Technology Data Exchange (ETDEWEB)

    Leininger, D.; Erdmann, W.; Schieder, T.; Koehling, R.; Petry, R.

    1982-11-11

    Because of the lack of suitable sites as well as because of environment and landscape protection, the objective of the German hard-coal mining industry is to find alternative ways of utilization of its preparation refuse, to reduce the quantities for disposal on waste heaps to the absolute minimum. Untreated washery refuse, however, can be only sold as a bulk material for improving the mechanical properties of the supporting soil in the construction of dams and dykes. Yet, by mechanical and thermal treatment, the preparation refuse can be converted into high-quality building materials which have a good chance to be sold at a profit if the quality characteristics required by the building construction and civil engineers are maintained. In the field of securing the valuable components of raw materials by recycling them the production of Al/sub 2/O/sub 3/ from washery refuse is possible, though not yet profitable with the present bauxite prices. The costs of refuse utilization depend on the degree of treatment as well as on the specific conditions as to raw material supply, plant operation and infrastructure.

  15. Jamaica.

    Science.gov (United States)

    1987-01-01

    The U.S. State Department's background notes on the Caribbean island nation of Jamaica discusses geography, people, history, government, defense and foreign relations, with lengthier sections on politics and economy. Jamaica, lying south of Cuba, has 10,991 sq. km., 2.3 million people of African and African-European origin primarily, a growth rate of 1.1%, infant mortality rate of 28/1000 and life expectancy of 71 years. The island has diverse climatic regions, mountainous structure, rich resources in bauxite, and agriculture. It was settled in the 1500s by Spain, occupied since 1670 Britain, and became independent in 1962. The first election in 1945 established the roots of the government, modeled after the British system. The 2 major parties, derived from preceding labor unions, are the Jamaican Labour Party, centrist but favoring private business and agriculture, and the People's National Party, more populist and socialist. The economy has suffered in recent years from recession, unemployment, high interest rates, international trade deficit and government spending deficits, as well as a brief alignment with Cuba that discouraged both tourism and foreign investment. Initiatives from U.S. investors have begun to reverse the trend, concentrating on establishment of light industry such as garment making and data entry. Jamaica's wealth in her stable government, literate population, natural resources, fertile soil, and good relations with other nations and institutions suggest that she will rise above her economic troubles.

  16. Novel applications of red mud as coagulant, adsorbent and catalyst for environmentally benign processes.

    Science.gov (United States)

    Wang, Shaobin; Ang, H M; Tadé, M O

    2008-08-01

    Red mud (RM) is a by-product of bauxite processing via the Bayer process. Its disposal remains an issue of great importance with significant environmental concerns. In the past decades, a lot of research has been done to utilize red mud for environmental-benign applications such as a building material additive and for metal recovery. In recent years, red mud has also been explored for gas cleaning and wastewater treatment. In this paper, we review varying novel applications of red mud as a coagulant and adsorbent for water and gas treatment as well as catalyst for some industrial processes. The environmental compatibility of red mud is discussed. Some directions of future research are also proposed. Red mud presents a promising application in water treatment for removal of toxic heavy metal and metalloid ions, inorganic anions such as nitrate, fluoride, and phosphate, as well as organics including dyes, phenolic compounds and bacteria. In addition, red mud can also be employed as catalysts for hydrogenation, hydrodechlorination and hydrocarbon oxidation. Moreover, leaching and eco-toxicological tests indicate that red mud does not present high toxicity to the environment before or after reuse.

  17. Optimising Ambient Setting Bayer Derived Fly Ash Geopolymers

    Directory of Open Access Journals (Sweden)

    Evan Jamieson

    2016-05-01

    Full Text Available The Bayer process utilises high concentrations of caustic and elevated temperature to liberate alumina from bauxite, for the production of aluminium and other chemicals. Within Australia, this process results in 40 million tonnes of mineral residues (Red mud each year. Over the same period, the energy production sector will produce 14 million tonnes of coal combustion products (Fly ash. Both industrial residues require impoundment storage, yet combining some of these components can produce geopolymers, an alternative to cement. Geopolymers derived from Bayer liquor and fly ash have been made successfully with a compressive strength in excess of 40 MPa after oven curing. However, any product from these industries would require large volume applications with robust operational conditions to maximise utilisation. To facilitate potential unconfined large-scale production, Bayer derived fly ash geopolymers have been optimised to achieve ambient curing. Fly ash from two different power stations have been successfully trialled showing the versatility of the Bayer liquor-ash combination for making geopolymers.

  18. 中国铝酸盐水泥的生产与发展

    Institute of Scientific and Technical Information of China (English)

    张宇震

    2003-01-01

    @@ 1铝酸盐水泥的诞生 铝酸盐水泥是耐火材料行业中不可缺少的一种水硬性粘结剂.该产品最早是1865年后期在法国出现,由氧化铝和石灰经熔融后破碎制成的铝酸钙水泥(calcium aluminate cement-CAC).19世纪末期英国首先发布了"石灰石-矾土(limestone bauxite cement)"水泥的专利.而首次进行这种水泥商业性生产则是在1913年法国的拉法基公司(Lafarge),生产方法为熔融法.铝酸盐水泥早期强度高,耐火性能优良,具有抗硫酸盐和弱酸侵蚀的能力,广泛应用于耐火材料行业.

  19. Thin layer chromatographic separation of cobalt from nickel on impregnated silica gel layers:quantitative determination by digital image analysis%Thin layer chromatographic separation of cobalt from nickel on impregnated silica gel layers: quantitative determination by digital image analysis

    Institute of Scientific and Technical Information of China (English)

    P A MOHAMED NAJAR; R G SONALI; M T NIMJE; K V RAMANA RAO

    2012-01-01

    Thin layer chromatography (TLC) of cobalt and nickel has been performed on silica gel layers induced with alkali mediated cellulose extract.A novel combination of 10% aqueous solutions of Tween-20 and potassium thiocyanate in 1∶ 1 (v/v) was identified as the best mobile phase for the selective separation of Co2+ from Ni2+ on the impregnated Silica Gel G layers.The chromatographic characteristics of the cations were studied and the limits of detection as well as the limits of quantification for Co2+ and Ni2+ were determined.The quantitative estimation of the cations was achieved from the digital image analysis of respective chromatograms.The proposed quantitative method was successfully applied with 0-0.50% error for the determination of Co2+ from Ni2+ in spiked samples of bauxite,soil and rock containing common cations such as Al3+,Fe2+,Ti4+,Zn2+,Mn2+,Cu2+,Cr6+,Mg2+ etc.under the optimized chromatographic conditions.

  20. Radionuclides in Bayer process residues: previous analysis for radiological protection

    Energy Technology Data Exchange (ETDEWEB)

    Cuccia, Valeria; Rocha, Zildete, E-mail: vc@cdtn.b, E-mail: rochaz@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Oliveira, Arno H. de, E-mail: heeren@nuclear.ufmg.b [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear

    2011-07-01

    Natural occurring radionuclides are present in many natural resources. Human activities may enhance concentrations of radionuclides and/or enhance potential of exposure to naturally occurring radioactive material (NORM). The industrial residues containing radionuclides have been receiving a considerable global attention, because of the large amounts of NORM containing wastes and the potential long term risks of long-lived radionuclides. Included in this global concern, this work focuses on the characterization of radioactivity in the main residues of Bayer process for alumina production: red mud and sand samples. Usually, the residues of Bayer process are named red mud, in their totality. However, in the industry where the samples were collected, there is an additional residues separation: sand and red mud. The analytical techniques used were gamma spectrometry (HPGe detector) and neutron activation analysis. The concentrations of radionuclides are higher in the red mud than in the sand. These solid residues present activities concentrations enhanced, when compared to bauxite. Further uses for the residues as building material must be more evaluated from the radiological point of view, due to its potential of radiological exposure enhancement, specially caused by radon emission. (author)

  1. The influence of titanium and iron oxides on the coloring and friability of the blue fired aluminum oxide as an abrasive material

    Directory of Open Access Journals (Sweden)

    E. R. Passos

    2016-03-01

    Full Text Available Abstract The quality of abrasive grains is crucial to increase the lifespan of roughing, polishing and cutting tools. The purpose of the work herein was to evaluate the variables of the blue fired aluminum oxide heat treatment process. This heat treatment process improves the physical properties of the brown fused aluminum oxide and results in a blue coloring, which uniquely identifies it within the abrasives industry. The work herein includes information beginning with the electro-fusion process of bauxite (the manufacturing of the brown fused aluminum oxide to the Blue Fired process. It also compares the fracture resistance index between these materials. This index is the inverse of the friability. Besides the content of titanium and iron oxides, process variables such as time, temperature and atmospheric conditions are important to monitor in order to reach standard requirements. Experimental evidence measuring these parameters is presented in the article herein. The blue coloring of this aluminum oxide is explained by the optical phenomena of electron transition, and not by the formation of aluminum titanate, as some technical literature has stated. Furthermore, it was proved that the coloring of blue fired material should not be used exclusively as an indicator of the optimal abrasive characteristics of this class of aluminum oxide.

  2. Review of cadmium transfers from soil to humans and its health effects and Jamaican environment.

    Science.gov (United States)

    Lalor, Gerald C

    2008-08-01

    Concerns about the effects of cadmium on human health have led to numerous guidelines and regulations limiting its concentrations in soils and food and allowable human intakes. These have socio-economic consequences in terms of land use and the marketing of food. The bauxite soils in Jamaica, which are both aluminium ores and agricultural soils contain orders of magnitude higher than world normal concentrations of cadmium resulting in elevated Cd concentrations in several foodstuffs and significant transfers to humans, which would seem to represent a risk factor for increased mortality and/or morbidity in the local populations. But, as in Shipham and other examples, there is no evidence of cadmium-related human distress. Macro-indicators like life expectancy and median ages of death do not show cadmium related geographical distributions. The present review focuses on the soils and foods and illnesses of high incidence especially cancers and renal disease that have been traditionally associated with cadmium. In view of the remarkable concentrations of cadmium involved in Jamaica, and often contradictory reports in the literature, it appears that much remains to be learned about certain details of cadmium toxicity.

  3. Carboniferous paleogeographic and paleoclimatic reconstructions

    Energy Technology Data Exchange (ETDEWEB)

    Scotese, C.R. (Univ. of Texas, Arlington, TX (United States). Dept. of Geology); Raymond, A. (Texas A and M Univ., College Station, TX (United States). Dept. Geology)

    1992-01-01

    The Carboniferous was an important transitional period in earth history. The Paleozoic oceans separating the continents of Gondwana, Laurentia, Baltica, Kazakhstan, and Siberia had closed by the late Carboniferous forming the late Paleozoic supercontinent of Pangea. Plate motions which appear to have been rapid during the Early Carboniferous (6--10 cm/yr), slowed to a temperature gradient increased as the Earth's climate changed from hot-house to ice-house conditions. Sea level, which stood high during the Early Carboniferous, fell as a result of continental collision and mountain-building, and then began to rise and fall rhythmically as the South Polar ice-cap waxed and waned. These environmental changes intersected important evolutionary events, namely, the explosive colonization of the emergent land areas by plants and the rise of terrestrial vertebrates. In this paper the authors present paleogeographic reconstructions for 6 intervals during the Carboniferous. These maps illustrate the latitudinal position of the continents deduced from paleomagnetic data and the distribution of climatically restricted lithofacies (coal, bauxite, evaporite, calcrete, and tillite), the inferred location of active plate boundaries, and the changing configuration of mountains, land, shallow seas, and deep ocean basins. For each of these paleogeographic maps a climatic simulation was run using the Parametric Climate Model. These simulations predict the distribution of high and low pressure cells, prevailing wind directions, pole-to-equator temperature gradient, relative wetness/dryness, as well as zones of coastal upwelling.

  4. Testing of a scanning adiabatic calorimeter with Joule effect heating of the sample.

    Science.gov (United States)

    Barreiro-Rodríguez, G; Yáñez-Limón, J M; Contreras-Servin, C A; Herrera-Gomez, A

    2008-01-01

    We evaluated a scanning adiabatic resistive calorimeter (SARC) developed to measure the specific enthalpy of viscous and gel-type materials. The sample is heated employing the Joule effect. The cell is constituted by a cylindrical jacket and two pistons, and the sample is contained inside the jacket between the two pistons. The upper piston can slide to allow for thermal expansion and to keep the pressure constant. The pistons also function as electrodes for the sample. While the sample is heated through the Joule effect, the electrodes and the jacket are independently heated to the same temperature of the sample using automatic control. This minimizes the heat transport between the sample and its surroundings. The energy to the sample is supplied by applying to the electrodes an ac voltage in the kilohertz range, establishing a current in the sample and inducing electric dissipation. This energy can be measured with enough exactitude to determine the heat capacity. This apparatus also allows for the quantification of the thermal conductivity by reproducing the evolution of the temperature as heat is introduced only to one of the pistons. To this end, the system was modeled using finite element calculations. This dual capability proved to be very valuable for correction in the determination of the specific enthalpy. The performance of the SARC was evaluated by comparing the heat capacity results to those obtained by differential scanning calorimetry measurements using a commercial apparatus. The analyzed samples were zeolite, bauxite, hematite, bentonite, rice flour, corn flour, and potato starch.

  5. Topography of the medullar cone in the short-eared dog (Atelocynus microtis Sclater, 1882: Case report

    Directory of Open Access Journals (Sweden)

    Kylma Lorena Saldanha

    2011-12-01

    Full Text Available Epidural anesthesia is one of the most common anesthetic techniques used because it is safe, efficient and can be quickly implemented. However, for each species undergoing this procedure, precise knowledge of the topography of the medullar cone is necessary. Therefore, this study aimed to describe the topography of the medullar cone of the short-eared dog (Atelocynus microtis, in order to provide relevant anatomical data for the practice of epidural anesthesia on this species. We used an exemplary young male, from the Bauxite Mine area (Paragominas, PA, which died of natural causes and was fixed and stored in 10% aqueous formaldehyde. The animal was dissected by removing the skin and epiaxial musculature, followed by the section and removal of vertebral arches, which exposed the medullar cone. The specimen studied had seven lumbar and three sacralvertebras. After the separation of the anatomical structures, the conus medullaris was measured with a digital caliper. The lumbar intumescence was located between L3 and L6, the medullar cone was observed in L7 and its apex in the S3, and had a total length of 3.9cm. We suggest that the sacrocaudal region is the most appropriate place to perform epidural anesthesia in Atelocynus microtis.

  6. Chemical elements in pearl oysters (Paxyodon ponderosus), phytoplankton and estuarine sediments from eastern Amazon (Northern Brazil): Bioaccumulation factors and trophic transfer factors

    Science.gov (United States)

    Vilhena, Maria P. S. P.; Costa, Marcondes L.; Berrêdo, José F.; Paiva, Rosildo S.; Souza, Crisvaldo C. S.

    2016-04-01

    The current study was conducted near Barcarena County, which is a mid-sized urban center where aluminum ore processing industries (bauxite) and Vila do Conde cargo terminal are located. It aims to discuss the bioaccumulation factors as well as factors related to the trophic transfer of chemical elements in water, oyster, phytoplankton and bottom sediments from an estuary in the Brazilian Northern coast. The bioaccumulation factor (BAF), trophic transfer factor (TTF) and biota-sediment-water were used to correlate the contents of chemical elements found in organisms. The sediment, surface water, phytoplankton and pearl oysters chemical composition was analyzed by ICP-OES and ICP-MS. Pearl oysters showed K, Ca, Mg, P, Mn, Fe, Zn, Al, Ba and Pb accumulation, which concentration increase is associated with their diet (phytoplankton). Al concentrations are 14 times higher in pearl oysters (Paxyodon ponderosus), assuming that they are associated with wastewater emissions and with industrialization processes in the area. BAF and BSAF values are 1000 times higher than the metal concentrations in water and bioavailable fraction concentrations. The oyster-phytoplankton trophic transfer factor indicates that P, Ba, Ca, Na, Cd and Zn showed the largest transfers (from 5 to 19). These trophic transfers may be sufficient to cause significant ecotoxicological effects on the region biota.

  7. Regulation of naturally occurring radioactive materials in Australia.

    Science.gov (United States)

    Jeffries, Cameron; Akber, Riaz; Johnston, Andrew; Cassels, Brad

    2011-07-01

    In order to promote uniformity between jurisdictions, the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) has developed the National Directory for Radiation Protection, which is a regulatory framework that all Australian governments have agreed to adopt. There is a large and diverse range of industries involved in mining or mineral processing, and the production of fossil fuels in Australia. Enhanced levels of naturally occurring radionuclides can be associated with mineral extraction and processing, other industries (e.g. metal recycling) and some products (e.g. plasterboard). ARPANSA, in conjunction with industry and State regulators, has undertaken a review and assessment of naturally occurring radioactive material (NORM) management in Australian industries. This review has resulted in guidance on the management of NORM that will be included in the National Directory for Radiation Protection. The first NORM safety guide provides the framework for NORM management and addresses specific NORM issues in oil and gas production, bauxite, aluminium and phosphate industries. Over time further guidance material for other NORM-related industries will be developed. This presentation will provide an overview of the regulatory approach to managing NORM industries in Australia.

  8. Validation of a procedure for the analysis of (226)Ra in naturally occurring radioactive materials using a liquid scintillation counter.

    Science.gov (United States)

    Kim, Hyuncheol; Jung, Yoonhee; Ji, Young-Yong; Lim, Jong-Myung; Chung, Kun Ho; Kang, Mun Ja

    2017-01-01

    An analytical procedure for detecting (226)Ra in naturally occurring radioactive materials (NORMs) using a liquid scintillation counter (LSC) was developed and validated with reference materials (zircon matrix, bauxite matrix, coal fly ash, and phosphogypsum) that represent typical NORMs. The (226)Ra was released from samples by a fusion method and was separated using sulfate-coprecipitation. Next, a (222)Rn-emanation technique was applied for the determination of (226)Ra. The counting efficiency was 238 ± 8% with glass vials. The recovery for the reference materials was 80 ± 11%. The linearity of the method was tested with different masses of zircon matrix reference materials. Using 15 types of real NORMs, including raw materials and by-products, this LSC method was compared with γ-spectrometry, which had already been validated for (226)Ra analysis. The correlation coefficient for the results from the LSC method and γ-spectrometry was 0.993 ± 0.058.

  9. Anatomical study of encephalic arterial circuit in Eira barbara

    Directory of Open Access Journals (Sweden)

    Breno Costa de Macedo

    2014-06-01

    Full Text Available Eira barbara is a mustelid with a wide distribution in Latin America, and it is commonly known as the grey-headed tayra. In view of the lack of information regarding the anatomy of mustelids, as well the importance of a vascular model for the understanding of neurological lesions in the central nervous system, this study aimed to determine the morphology and composition of the encephalic arterial circuit of E. barbara, to provide data for future studies. Accordingly, we used two young male specimens, obtained from the area of the Paragominas Bauxite Mine, PA, Brazil, donated to LaPMA after their death. The arterial system was filled with red-colored neoprene latex, and the specimens were then fixed in 10% formaldehyde and dissected for systematization of the blood vessels. The specimens showed the arterial circuit in the base of the brain supplied by the internal carotid arteries and basilar artery. The internal carotid artery, after crossing the dura mater, continued cranially giving rise to the medial cerebral arteries and ending as cranial cerebral arteries that anastomose, closing the arterial circuit rostrally. The caudal communicating arteries integrated the basilar artery with the arterial circle and gave rise to the caudal cerebral and rostral cerebellar arteries. The basilar artery formed the main branches, the medial and caudal cerebellar arteries.

  10. Immobilization of trace elements in municipal solid waste incinerator (MSWI) fly ash by producing calcium sulphoaluminate cement after carbonation and washing.

    Science.gov (United States)

    Wang, Lei; Jamro, Imtiaz Ali; Chen, Qi; Li, Shaobai; Luan, Jingde; Yang, Tianhua

    2016-03-01

    The possibility of producing calcium sulphoaluminate cement (CSA) by adding municipal solid waste incinerator (MSWI) fly ash to raw meal was investigated. After subjecting MSWI fly ash to accelerated carbonation and washing with water (ACW), various amounts (i.e., 5, 10 and 15 wt%) of the treated ash were added to raw meal composed of a mixture of bauxite, limestone and gypsum. The mixtures were sintered in a laboratory-scale muffle furnace at temperatures of 1250°, 1300°, 1325° and 1350 °C for various durations. The influence of different quantities of MSWI fly ash on the mineralogy, major phase composition and strength development of the resulting clinker was studied, as was the effect of ash treatments on leaching and volatilization of trace elements. The ACW treatment reduced the volatilization ratio of trace elements during the clinkerization process. Volatilization ratios for lead, cadmium and zinc were 21.5%, 33.6% and 16.3%, respectively, from the ACW fly ash treatment, compared with ratios of 97.5%, 93.1% and 85.2% from untreated fly ash. The volatilization ratios of trace elements were ordered as follows: untreated fly ash > carbonated fly ash > carbonated and water-washed fly ash. The ACW process also reduced the chloride content in the MSWI fly ash by 90 wt% and prevented high concentrations of trace elements in the effluents.

  11. Removal of Phosphate Using Red Mud: An Environmentally Hazardous Waste By-Product of Alumina Industry

    Directory of Open Access Journals (Sweden)

    Shivkumar S. Prajapati

    2016-01-01

    Full Text Available The industrial waste, bauxite residue generated in the Bayer chemical process of alumina production, commonly known as red mud (RM has been used as the adsorbent for selective removal of phosphate in aqueous solutions. RM collected from the storage area of alumina industry was characterized by chemical analysis and physical methods such as BET surface area, Scanning Electron Microscopy (SEM, particle size analysis, and X-ray diffraction (XRD methods. Among the various red mud samples (0.2–200 μ studied, the samples treated with 1 M HCl for 2 h were found better for the selective adsorption of phosphate in comparison with untreated and heat treated RM samples. The presence of phosphate in the aqueous samples collected after adsorption studies with red mud was determined by standard spectrophotometric procedure using ammonium molybdate and ascorbic acid in nitrate medium at λmax 880 nm. The studies reported significant adsorption of phosphate on acid treated red mud in comparison with adsorption of phosphate on untreated and heat treated red mud, respectively. The adsorption of phosphate on raw red mud and activated red mud was further investigated with respect to stirring time, pH of the solution, dose of adsorbent, and varying phosphate concentration. Acid treated RM is observed as an efficient and cost-effective adsorbent for selective removal of phosphate in aqueous solutions.

  12. Comparison of microbial communities in pilot-scale bioreactors treating Bayer liquor organic wastes.

    Science.gov (United States)

    McSweeney, Naomi J; Plumb, Jason J; Tilbury, Amanda L; Nyeboer, Hugh J; Sumich, Matt E; McKinnon, Anthony J; Franzmann, Peter D; Sutton, David C; Kaksonen, Anna H

    2011-04-01

    Western Australian bauxite deposits are naturally associated with high amounts of humic and fulvic materials that co-digest during Bayer processing. Sodium oxalate remains soluble and can co-precipitate with aluminium hydroxide unless it is removed. Removal of sodium oxalate requires a secondary crystallisation step followed by storage. Bioreactors treating oxalate wastes have been developed as economically and environmentally viable treatment alternatives but the microbial ecology and physiology of these treatment processes are poorly understood. Analysis of samples obtained from two pilot-scale moving bed biofilm reactors (MBBRs) and one aerobic suspended growth bioreactor (ASGB) using polymerase chain reaction- denaturing gradient gel electrophoresis of 16S rRNA genes showed that members of the α-, β- and γ-Proteobacteria subgroups were prominent in all three processes. Despite differing operating conditions, the composition of the microbial communities in the three reactors was conserved. MBBR2 was the only configuration that showed complete degradation of oxalate from the influent and the ASGB had the highest degradation rate of all three configurations. Several strains of the genus Halomonas were isolated from the bioreactors and their morphology and physiology was also determined.

  13. Mechanical Properties of Solid-State Recycled 4xxx Aluminum Alloy Chips

    Science.gov (United States)

    Tokarski, Tomasz

    2016-08-01

    The direct production of aluminum from bauxite ores is known to be a very energetic-intensive operation compared to other metallurgical processes. Due to energy issues and the rapid increase in aluminum demand, new kinds of aluminum production processes are required. Aluminum waste recycling, which has an advantage of lowering the cost of electric power consumption, is considered to be an alternative route for material manufacturing. In this work, the way of reusing aluminum EN-AC 44000 alloy scraps by hot extrusion was presented. Metal chips of different sizes and morphology were cold compacted into billet form and then hot extruded. Mechanical properties investigations combined with microstructure observations were performed. Mechanical anisotropy behavior of material was evaluated on the base of tensile test experiments performed on samples machined at 0°, 45°, and 90°, respectively, to the extrusion direction. It was found that the initial size of the chips has an influence on the mechanical properties of the received profiles. Samples produced from fine chips revealed higher tensile strength in comparison to larger chips, which can be attributed to a refined microstructure containing fine, hard Si particles and Fe-rich intermetallic phases. Finally, it was found that anisotropic behavior of chip-based profiles is similar to conventionally cast and extruded materials which prove good bonding quality between chips.

  14. 合理利用资源生产铝酸钙精炼渣的研究%Study on Producing Calcium Aluminate by Optimal Use of Resources

    Institute of Scientific and Technical Information of China (English)

    张延大

    2012-01-01

    钢铁冶炼会消耗大量的优质矿产资源,本文通过分析石灰岩、矾土矿等相关资源储量形势,指出了利用工业废渣作为原材料生产铝酸钙精炼渣的可行性,并在轴承钢生产中得到了理想的应用效果,脱硫率最高达到了83.5%,钛显微夹杂物显著降低.这对合理利用资源,实现可持续发展具有重要意义.%It consumes a lot of premium resources to make iron and steel. This paper dwells on the reserve situation of limestone and bauxite, indicating the feasibility of producing calcium aluminate refining slag by taking use of industrial offscum and it has been effectively used in bearing steel with desulfurization rate reaching 83.5% and micro-titanium impurity decreasing remarkably, which has important influence on the rational use of recourses and sustainable development.

  15. Historical trends in U.S. mineral statistics for selected non-ferrous metals

    Science.gov (United States)

    Piper, David Z.; Nokleberg, Warren J.

    2002-01-01

    Production figures for selected nonferrous metals-aluminum (including bauxite and alumina), copper, lead, tin, titanium, and zinc-by the United States, as well as other statistics for these commodities, show strong volatility during 20th century. Major shifts were driven by the Great Depression and the two World Wars, but other major temporal changes are also noted that are not directly related to such global crises. For example, the price of tin exhibited a strong maximum in the 1980's, which is unrelated to world production, but rather to failed efforts of the International Tin Council to control price. In the case of copper, U.S. exports have varied throughout the second half of the century, by more than a factor of 5. Such volatility might be explained in part by global economic conditions, at least throughout recent decades. Supporting the interpretation of the importance of foreign pressure on the domestic commodities market is a close correlation between domestic consumption of antimony and its elevated price in the mid 1980's,possibly pushed up mostly by the world dominance in production of this commodity by China. However, only very superficial explanations can be advanced for such relations before we have examined, in concert, information for a much larger suite of commodities.

  16. Petrogenesis of tourmaline rocks associated with Fe-carbonate graphite metapelite, metabasite and strata-bound polymetallic sulphide mineralisation, Peloritani Mountains, Sicily, Southern Italy

    Science.gov (United States)

    Ferla, Paolo; Meli, Carmelina

    2007-12-01

    Tourmalinite and tourmaline-rich rocks associated with Fe-carbonate-graphite phyllite, strata-bound polymetallic sulphide deposits, metabasite and marble were studied, for information on the mechanism of tourmaline formation in the pre-Hercynian low-grade metamorphic sequence of the Mandanici Unit in the Peloritani Mountains of Sicily, southern Italy. The major and trace element compositions of the tourmaline rocks suggest the existence of a sedimentary protolith with pre-metamorphic black shale and bedded chert. Boron was interpreted to be accumulated in a restricted sedimentary basin, between platform carbonate formations, with abundant organic matter and Fe-Al-Ti-rich laterite-bauxite soil-derived clastic supply, under a continental volcano-tectonic extensional regime accompanied by a local convective hydrothermal system along faults. Petrographic, crystal-chemical and δ11B isotopic data are compatible with a model of marine sediment dewatering at temperatures below 200 °C, which caused the removal of boron from clay. Metamorphism led to the development of tourmaline in an Al-Ti-rich environment, in equilibrium with other minerals such as ilmenite, albite and muscovite. The upper temperature of metamorphism (almost 375 °C), estimated on the basis of δ11B, fits geothermometric results from Δ 13C carbonate-graphite on associated rocks. The estimated value of δ11B in the tourmalinite protolith, - 7.5‰ , is also compatible with continental-derived Al-rich sediments.

  17. MSWI Fly Ash Based Novel Solidification/Stabilization Matrices for Heavy Metals

    Institute of Scientific and Technical Information of China (English)

    DENG Faqing; QIAN Guangren

    2008-01-01

    The possibilities of MSWI fly ash as a major constituent of novel solidification/stabilization matrices for secure landfill were investigated by mixing MSWl fly ash with rich aluminum components,which was added as bauxite cement or metakaolinite instead,to form Friedel and Ettringite phases with high fixing capacities for heavy metals.The physical properties,heavy metals-fixing capacity,mineral phases and its vibration bands in the novel matrices were characterized by compressive strength,TCLP(toxic characteristic leaching procedure),XRD (x-ray diffraction),DTG (derivative thermogravimetry),and FTIR (fourier transform infrared spectroscopy),respectively.The Tessier's five-step sequential extraction procedure was used to analyze the fractions of chemical speciation for Pb,Cd and Zn ions.The experimental results indicate that Friedel-Ettringite based novel solidification/stabilization matrices can incorporate Pb,Cd and Zn ions effectively by physical encapsulation and chemical fixation,and it exhibits a great potential in co-landfill treatment of MSWI fly ash with some heavy metals-bearing hazardous wastes.

  18. Environmental and technological effectiveness of a process for the stabilization of a galvanic sludge.

    Science.gov (United States)

    Cioffi, R; Lavorgna, M; Santoro, L

    2002-01-28

    A binding matrix containing calcium silicate beta-2CaO.SiO(2) and sulphoaluminate 4CaO.3Al(2)O(3).SO(3), and CaSO(4) that gives calcium silicate and trisulphoaluminate hydrates upon hydration has been used for the stabilization of a solid waste from a galvanic treatment process. The waste is to be disposed of in a hazardous wastes landfill to prevent the risk of cadmium, chromium and nickel release. Anhydrous calcium silicate and sulphoaluminate of the binder have been synthesized using a mixture containing powdered tuff in addition to bauxite and calcium carbonate and sulphate. Powdered tuff is quarry dust and is, as such, a true residue. Experiments have been carried out with mixtures containing up to 60% waste and have been addressed towards the environmental and technological assessment of the effectiveness of the stabilization process. Specifically, the study has been carried out taking into account requirements from three different points of view, that is the influence of the waste on the hydration process and on the technological properties of the stabilized products, the leaching behavior under some selected conditions and the effect of the leaching medium on the binding matrix in the stabilized system.

  19. Evaluation of red mud as pozzolanic material in replacement of cement for production of mortars; Avaliacao da lama vermelha como material pozolanico em substituicao ao cimento para producao de argamassas

    Energy Technology Data Exchange (ETDEWEB)

    Manfroi, E.P.; Cheriaf, M.; Rocha, J.C., E-mail: elizmanfroi@yahoo.com.b, E-mail: malik@valores.ufsc.b [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Civil

    2010-07-01

    Red mud is a by-product of the alkaline extraction of aluminum from the bauxite and represents a renewed environmental problem due the significant annual throughput by the plants. In the present work, the pozzolanic properties of Brazilian red mud fired at 600, 700, 800 and 900 deg C were investigated by monitoring lime consumption using DTA analysis and Brazilian standard methodology NBR 5772 (1992). Products and kinetics of hydration were determined in cement pastes produced with 5 and 15% red mud using x-ray diffraction and DTA analysis. Compressive strength and capillary absorption tests were realized on mortars constituted by 5, 10 and 15% red mud in replacement of cement. When calcined at 600 deg C, the red mud develops good pozzolanic properties, and the compressive strength of mortars produced with this waste meet values in accordance with regulatory standard. These results shown than red mud can be used, in partial replacement of cement, as new construction material to produce sustainable mortars with low environmental impact. (author)

  20. Advances in chemical and physical properties of electric arc furnace carbon steel slag by hot stage processing and mineral mixing.

    Science.gov (United States)

    Liapis, Ioannis; Papayianni, Ioanna

    2015-01-01

    Slags are recognised as a highly efficient, cost effective tool in the metal processing industry, by minimising heat losses, reducing metal oxidation through contact with air, removing metal impurities and protecting refractories and graphite electrodes. When compared to natural aggregates for use in the construction industry, slags have higher specific weight that acts as an economic deterrent. A method of altering the specific weight of EAFC slag by hot stage processing and mineral mixing, during steel production is presented in this article. The method has minimal interference with the production process of steel, even by limited additions of appropriate minerals at high temperatures. Five minerals are examined, namely perlite, ladle furnace slag, bauxite, diatomite and olivine. Measurements of specific weight are accompanied by X-ray diffraction (XRD) and fluorescence (XRF) analysis and scanning electron microscopy spectral images. It is also shown how altering the chemical composition is expected to affect the furnace refractory lining. Additionally, the process has been repeated for the most suitable mix in gas furnace and physical properties (FI, SI, LA, PSV, AAV, volume stability) examined. Alteration of the specific weight can result in tailoring slag properties for specific applications in the construction sector.

  1. Genetic analyses determine connectivity among cave and surface populations of the Jamaican endemic freshwater crab Sesarma fossarum in the Cockpit Country

    Directory of Open Access Journals (Sweden)

    Manuel Stemmer

    2016-01-01

    Full Text Available The Jamaican freshwater crab Sesarma fossarum (Decapoda: Brachyura: Sesarmidae is endemic to western central Jamaica where it occurs in cave and surface streams of karst regions. In the present study, we examine the population genetic structure of the species, providing evidence for intraspecific differentiation and genetic substructure among twelve sampled populations. Interestingly, crabs from caves appear genetically undistinguishable from representatives of nearby surface waters, despite previously observed and described morphometric differentiation. In contrast, genetic isolation takes place among populations from rivers and caves belonging to different watersheds. In one case, even populations from different tributaries of the same river were characterized by different genotypes. Overall, the species shows low haplotype and nucleotide diversities, which indicates a high homogeneity and point towards a relatively recent intraspecific radiation and diversification. Our results on the genetic diversification of S. fossarum helps to reconstruct unknown subterranean water flow and cave connections in its native range, allowing prediction of its further dispersal and differentiation potential. Unfortunately, its natural habitat of Jamaican cockpit karst, which also is home to several other endemic species and is a globally-recognized Key Biodiversity Area, is under imminent threat of intensive bauxite mining.

  2. Carbon emissions and resources use by Chinese economy 2007: A 135-sector inventory and input-output embodiment

    Science.gov (United States)

    Chen, G. Q.; Chen, Z. M.

    2010-11-01

    A 135-sector inventory and embodiment analysis for carbon emissions and resources use by Chinese economy 2007 is presented in this paper by an ecological input-output modeling based on the physical entry scheme. Included emissions and resources belong to six categories as: (1) greenhouse gas (GHG) in terms of CO 2, CH 4, and N 2O; (2) energy in terms of coal, crude oil, natural gas, hydropower, nuclear power, and firewood; (3) water in terms of freshwater; (4) exergy in terms of coal, crude oil, natural gas, grain, bean, tuber, cotton, peanut, rapeseed, sesame, jute, sugarcane, sugar beet, tobacco, silkworm feed, tea, fruits, vegetables, wood, bamboo, pulp, meat, egg, milk, wool, aquatic products, iron ore, copper ore, bauxite, lead ore, zinc ore, pyrite, phosphorite, gypsum, cement, nuclear fuel, and hydropower; (5) and (6) solar and cosmic emergies in terms of sunlight, wind power, deep earth heat, chemical power of rain, geopotential power of rain, chemical power of stream, geopotential power of stream, wave power, geothermal power, tide power, topsoil loss, coal, crude oil, natural gas, ferrous metal ore, non-ferrous metal ore, non-metal ore, cement, and nuclear fuel. Accounted based on the embodied intensities are carbon emissions and resources use embodied in the final use as rural consumption, urban consumption, government consumption, gross fixed capital formation, change in inventories, and export, as well as in the international trade balance. The resulted database is basic to environmental account of carbon emissions and resources use at various levels.

  3. N-(6-(hydroxyamino)-6-oxohexyl) decanamide collector: Flotation performance and adsorption mechanism to diaspore

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Lanqing [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Yueyang Chinese Herbal Utilization, Yueyang Vocational Technical College, Yueyang 414000 (China); Wang, Shuai [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Zhong, Hong, E-mail: zhongh@csu.edu.cn [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Liu, Guangyi, E-mail: guangyiliu@csu.edu.cn [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China)

    2015-08-30

    Graphical abstract: The potential absorption model of NHOD on diaspore surface. - Highlights: • A novel surfactant NHOD was first introduced as diaspore flotation collector. • NHOD exhibited superior collecting power to diaspore against gangue. • NHOD's has double active centers to mineral surfaces and double hydrophobic groups. • NHOD molecules formed intermolecular hydrogen bonds on diaspore surfaces. - Abstract: In this paper, a novel surfactant, N-(6-(hydroxyamino)-6-oxohexyl)decanamide (NHOD) was synthesized and used as a collector for flotation separation of diaspore and aluminosilicate minerals. The adsorption mechanism of NHOD onto diaspore was also investigated by FTIR spectra, zeta potential measurement and XPS. The flotation results demonstrated that NHOD exhibited superior collecting power to diaspore and selectivity against kaolinite and illite and could effectively realize flotation recovery of diaspore from bauxite ores contained aluminosilicate minerals under neutral conditions. The results of XPS, FTIR spectra and zeta potential illustrated that at around pH 7.0, NHOD might chemisorb on diaspore surfaces through Al−O coordination bonds formed by binding its −C(=O)NHOH or −C(=O)NH− chelate groups with aluminum atoms on diaspore surfaces. NHOD's unique properties, such as characteristic bond patterns onto diaspore surfaces, two hydrophobic groups, and intermolecular hydrogen bonds between neighboring NHOD molecules coated on diaspore surfaces, rendered it to be a superior flotation collector for diaspore.

  4. Synthesis of γ-alkoxy-propylamines and their collecting properties on aluminosilicate minerals

    Institute of Scientific and Technical Information of China (English)

    曹学锋; 胡岳华; 徐兢

    2004-01-01

    γ-alkoxy-propylamines, C12 H25 O(CH2 )3 NH2, C14 H29 O(CH2)3 NH2, C16 H33 O(CH2)3 NH2, C18 H37 O-(CH2)3NH2 were synthesized from aliphatic alcohol and acrylonitrile. The flotation tests of kaolinite, pyrophyllite and illite were conducted. The flotation mechanisms were explained in view of the structures of reagents and alumin ium silicate minerals, zeta potential and Fourier transform infrared spectrum measurements. The results show that the synthesized r-alkoxy-propylamines are more effective than dodecyl amine for flotation of kaolinite, pyrophyllite and illite. For flotation kaolinite and illite, the collecting ability is in the order of C18 H37 O(CH2)3 NH2 >C16 H33O(CH2)3 NH2 >C14 H29O(CH2 )3 NH2 >C12 H25O(CH2)3 NH2, but the r-alkoxy-propylamines types of collectors have almost the same collecting ability on pyrophyllite,which demonstrating that γ-alkoxy-propylamines are new selective collectors for reverse floatation to remove aluminium silicate minerals from bauxite.

  5. Use of object-oriented classification and fragmentation analysis (1985-2008) to identify important areas for conservation in Cockpit Country, Jamaica.

    Science.gov (United States)

    Newman, Minke E; McLaren, Kurt P; Wilson, Byron S

    2011-01-01

    Forest fragmentation is one of the most important threats to global biodiversity, particularly in tropical developing countries. Identifying priority areas for conservation within these forests is essential to their effective management. However, this requires current, accurate environmental information that is often lacking in developing countries. The Cockpit Country, Jamaica, contains forests of international importance in terms of levels of endemism and overall diversity. These forests are under severe threat from the prospect of bauxite mining and other anthropogenic disturbances. In the absence of adequate, up-to-date ecological information, we used satellite remote sensing data and fragmentation analysis to identify interior forested areas that have experienced little or no change as priority conservation sites. We classified Landsat images from 1985, 1989, 1995, 2002, and 2008, using an object-oriented method, which allowed for the inclusion of roads. We conducted our fragmentation analysis using metrics to quantify changes in forest patch number, area, shape, and aggregation. Deforestation and fragmentation fluctuated within the 23-year period but were mostly confined to the periphery of the forest, close to roads and access trails. An area of core forest that remained intact over the period of study was identified within the largest forest patch, most of which was located within the boundaries of a forest reserve and included the last remaining patches of closed-broadleaf forest. These areas should be given highest priority for conservation, as they constitute important refuges for endemic or threatened biodiversity. Minimizing and controlling access will be important in maintaining this core.

  6. DETERMINATION OF RESOLUTION LIMITS OF ELECTRICAL TOMOGRAPHY ON THE BLOCK MODEL IN A HOMOGENOUS ENVIRONMENT BY MEANS OF ELECTRICAL MODELLING

    Directory of Open Access Journals (Sweden)

    Franjo Šumanovac

    2007-12-01

    Full Text Available The block model in a homogenous environment can generally serve for presentation of some geological models: changes of facies, changes of rock compactness-fragmentation, underground cavities, bauxite deposits, etc. Therefore, on the block model of increased resistivities in a homogenous environment of low resistivity, the potentials of the electrical tomography method were tested for the purpose of their detection. Regarding potentials of block detection, resolution methods depend on: depth of block location, ratio between block resistivity and the environment in which it is located as well as applied survey geometry, i.e. electrode array. Thus the analyses carried out for the most frequently used electrode arrays in the investigations are the following: the Wenner, Wenner-Schlumberger, dipole-dipole and pole-pole arrays. For each array, maximum depths at which a block can be detected relative to the ratio between block resistivity and parent rock environment were analyzed. The results are shown in the two-dimensional graphs, where the ratio between the block resistivity and the environment is shown on the X-axis, and the resolution depth on the Y-axis, after which the curves defining the resolution limits were drawn. These graphs have a practical use, since they enable a fast, simple determination of potentials of the method application on a specific geological model.

  7. Properties and application of carbon composite brick for blast furnace hearth

    Directory of Open Access Journals (Sweden)

    Jiao K.X.

    2015-01-01

    Full Text Available A type of carbon composite brick was produced via the microporous technique using natural flack graphite, α-Al2O3 and high-quality bauxite chamotte (Al2O3≥87 mass% as raw materials with fine silicon powder as additive. The composition and microstructure of the obtained carbon composite were characterized using chemical analysis, XRD and SEM with EDS. The high temperature properties of thermal conductivity, oxidization and corrosion by molten slag and hot metal of the composite were analyzed. Based on these, the type of carbon composite brick worked in a blast furnace hearth for six years was further sampled at different positions. The protective layer was found and its chemical composition and microscopic morphology were investigated. It is found that the carbon composite brick combines the good properties of both the conventional carbon block and ceramic cup refractory. The protective layer near the hot face consists of two separated sublayers, i.e. the slag layer and the carbon layer. A certain amount of slag phase is contained in the carbon layer, which is caused by the reaction of coke ash with the refractory. No obvious change in the chemical composition of the protective layer along the depth of the sidewall is found. This work provides a useful guidance for the extension of the lifetime of blast furnace hearths.

  8. Speciation of arsenic, chromium, and vanadium in red mud samples from the Ajka spill site, Hungary.

    Science.gov (United States)

    Burke, Ian T; Mayes, William M; Peacock, Caroline L; Brown, Andrew P; Jarvis, Adam P; Gruiz, Katalin

    2012-03-20

    Results are presented from X-ray absorption spectroscopy based analysis of As, Cr, and V speciation within samples of bauxite ore processing residue (red mud) collected from the spill site at Ajka, Western Hungary. Cr K-edge XANES analysis found that Cr is present as Cr(3+) substituted into hematite, consistent with TEM analysis. V K-edge XANES spectra have E(1/2) position and pre-edge features consistent with the presence of V(5+) species, possibly associated with Ca-aluminosilicate phases. As K-edge XANES spectra identified As present as As(5+). EXAFS analysis reveals arsenate phases in red mud samples. When alkaline leachate from the spill site is neutralized with HCl, 94% As and 71% V are removed from solution during the formation of amorphous Al-oxyhydroxide. EXAFS analysis of As in this precipitate reveals the presence of arsenate Al-oxyhydroxide surface complexes. These results suggest that in the circumneutral pH, oxic conditions found in the Torna and Upper Marcal catchments, incorporation and sorption, respectively, will restrict the environmental mobility of Cr and As. V is inefficiently removed from solution by neutralization, therefore, the red mud may act as a source of mobile V(5+) where the red mud deposits are not removed from affected land.

  9. Radiological aspects of red mud disaster in Hungary

    Science.gov (United States)

    Kovács, Tibor; Sas, Zoltán; Jobbágy, Viktor; Csordás, Anita; Szeiler, Gábor; Somlai, János

    2013-08-01

    One of the most severe industrial catastrophes happened in Kolontár, Hungary, on 4 October 2010. Red mud (bauxite residue) broke through the eroded wall of the red mud reservoir pond "Number X" and flooded the surrounding area. This led to the instant death of 10 people and the injury of more than 100 people. Red mud is enriched in radium and thorium isotopes; therefore, there is a chance that this flooding will increase radionuclide concentrations of soils and also in air. In this study we have examined the site to assess the realistic radiological risks. For the risk assessment the following parameters were determined: gamma dose rate, radon concentration, radionuclide concentration of red mud and air dust concentration. It was found that the radiation dose exposure resulting from red mud contamination was < 0.045 mSv y-1 (excluding radon), which can be considered negligible when compared to the average annual effective dose from natural sources (2.4 mSv y-1).

  10. Red mud as a carbon sink: variability, affecting factors and environmental significance.

    Science.gov (United States)

    Si, Chunhua; Ma, Yingqun; Lin, Chuxia

    2013-01-15

    The capacity of red mud to sequester CO(2) varied markedly due to differences in bauxite type, processing and disposal methods. Calcium carbonates were the dominant mineral phases responsible for the carbon sequestration in the investigated red mud types. The carbon sequestration capacity of red mud was not fully exploited due to shortages of soluble divalent cations for formation of stable carbonate minerals. Titanate and silicate ions were the two major oxyanions that appeared to strongly compete with carbonate ions for the available soluble Ca. Supply of additional soluble Ca and Mg could be a viable pathway for maximizing carbon sequestration in red mud and simultaneously reducing the causticity of red mud. It is roughly estimated that over 100 million tonnes of CO(2) have been unintentionally sequestered in red mud around the world to date through the natural weathering of historically produced red mud. Based on the current production rate of red mud, it is likely that some 6 million tonnes of CO(2) will be sequestered annually through atmospheric carbonation. If appropriate technologies are in place for incorporating binding cations into red mud, approximately 6 million tonnes of additional CO(2) can be captured and stored in the red mud while the hazardousness of red mud is simultaneously reduced.

  11. Leaching of metals from fresh and sintered red mud.

    Science.gov (United States)

    Ghosh, Indrani; Guha, Saumyen; Balasubramaniam, R; Kumar, A V Ramesh

    2011-01-30

    The disposal of red mud, a solid waste generated during the extraction of alumina from bauxite, is one of the major problems faced by the aluminum industry. Proper disposal followed by its utilization, for example as bricks, can provide a satisfactory solution to this problem. Pollution potential of red mud and its finished product, due to metals leaching out from them under certain environmental conditions, need to be studied. Sintering of red mud was performed in a resistance type vertical tube furnace to simulate the brick-making conditions in lab-scale. Leachability of metals in red mud and the sintered product was evaluated by performing sequential extraction experiments on both. The metals studied were the 'macro metals' iron and aluminum and the 'trace metals' copper and chromium. The total extractabilities of all the metals estimated by the microwave digestion of red mud samples decreased due to sintering. The leachability in sequential extraction of the macro metals iron and aluminum, on the other hand, increased due to sintering in all phases of sequential extraction. However, the effect of sintering on the leachability of the trace metals by sequential extraction was different for copper and chromium in different fractions of sequential extraction.

  12. An active dealkalization of red mud with roasting and water leaching.

    Science.gov (United States)

    Zhu, Xiaobo; Li, Wang; Guan, Xuemao

    2015-04-09

    The research has focused on the dealkalization of red mud after active roasting and water leaching, which is obtained from bauxite during alumina production. The main factors such as roasting temperature, roasting time, water leaching stage, leaching temperature, leaching reaction time and liquid to solid ratio were investigated. The mechanism of dealkalization was in-depth studied by using ICP-AES, XRD, TG-DSC, SEM-EDS and leaching kinetic. The results show that the dealkalization rate reached 82% under the condition of roasting temperature of 700 °C, roasting time of 30 min, four stage water leaching, liquid to solid ratio of 7 mL/g, leaching temperature of 90 °C and reaction time of 60 min. The diffraction peak of Na6CaAl6Si6(CO3)O24 · 2H2O in red mud was decreased during the active roasting process, whereas the mineral phases of NaOH · H2O and Na2Ca(CO3)2 were appeared. The content of alkali obviously decreased and the grade of other elements increased during the process of active roasting and water leaching, which was in favor of next application process of red mud. The water leaching was controlled by internal diffusion of SCM and the apparent activation energy was 22.63 kJ/mol.

  13. Effects of thermal treatments on the characterisation and utilisation of red mud with sawdust additive.

    Science.gov (United States)

    Liu, Yanju; Naidu, Ravi; Ming, Hui; Dharmarajan, Rajarathnam; Du, Jianhua

    2016-06-01

    Extremely large amounts of red mud (bauxite residue) are generated globally every year from alumina refining industries, which are being disposed of on engineered landfills. The objective of this study is to investigate the effects of thermal treatments on red mud for development of utilisation strategies. Thermal treatments of red mud samples and their characterisations were investigated under inert (N2) and oxidative (air) conditions with and without sawdust addition at 200-600°C. After calcination, the resulting samples were analysed using thermogravimetric-infrared spectroscopy (TG-IR) for functional group transformations, thermogravimetric analysis (TGA) for thermal loss profiles and X-ray diffraction (XRD) for mineral transformations. The characterisation results showed that in N2 environment, boehmite in red mud was transferred to transition alumina at around 400°C while losing water from structural components. The addition of sawdust for incubation and calcination of red mud in air increased the surface area, whereas that in nitrogen atmosphere lead to reduction of hematite to magnetite at around 500°C. The incorporated carbon materials played a major role in increasing the surface area especially for pore size less than 2.5 nm. This treated red mud with altered mineral composition and improved properties for binding contaminants can be used for environmental remediation and in the process of metal recovery such as iron.

  14. Contaminant mobility and carbon sequestration downstream of the Ajka (Hungary) red mud spill: The effects of gypsum dosing.

    Science.gov (United States)

    Renforth, P; Mayes, W M; Jarvis, A P; Burke, I T; Manning, D A C; Gruiz, K

    2012-04-01

    A number of emergency pollution management measures were enacted after the accidental release of caustic bauxite processing residue that occurred in Ajka, western Hungary in October, 2010. These centred on acid and gypsum dosing to reduce pH and minimise mobility of oxyanion contaminants mobile at high pH. This study assessed the effectiveness of gypsum dosing on contaminant mobility and carbon sequestration through assessment of red mud and gypsum-affected fluvial sediments via elemental analysis and stable isotope analysis. There was a modest uptake of contaminants (notably As, Cr, and Mn) on secondary carbonate-dominated deposits in reaches subjected to gypsum dosing. C and O stable isotope ratios of carbonate precipitates formed as a result of gypsum dosing were used to quantify the importance of the neutralisation process in sequestering atmospheric carbon dioxide. This process was particularly pronounced at sites most affected by gypsum addition, where up to 36% of carbonate-C appears to be derived from atmospheric in-gassing of CO(2). The site is discussed as a large scale analogue for potential remedial approaches and carbon sequestration technologies that could be applied to red mud slurries and other hyperalkaline wastes. The results of this work have substantial implications for the aluminium production industry in which 3-4% of the direct CO(2) emissions may be offset by carbonate precipitation. Furthermore, carbonation by gypsum addition may be important for contaminant remediation, also providing a physical stabilisation strategy for the numerous historic stockpiles of red mud.

  15. 云南文山铝业赤泥资源化利用方案设想%Resource Utilization Scheme Assumption of Red Mud in Yunnan Wenshan Aluminum Co., Ltd.

    Institute of Scientific and Technical Information of China (English)

    栾景丽; 张敬奇; 闫森; 王灏

    2012-01-01

    A kind of treatment scheme of red mud resource utilization in Yunnan Wenshan Aluminum Co. , Ltd. Is presented in this paper according to the raw ore composition of bauxite, production process of alumina and the industry planning of Yunnan province. The mixed concentrate of iron and titanium can be selected from red mud by means of beneficiation process optimization, and then the high-titanium slag can be produced by electric furnace smelting, which can be the raw material for titanium dioxide production. The tailings of red mud can be widely used in building materials after decreasing of iron and alkali content through mineral processing, which the amount of red mud can be increased.%根据铝土矿原矿成分、氧化铝生产工艺和云南省的产业发展规划,提出了文山铝业拜耳法赤泥资源化利用的一种处理方案.赤泥通过选矿工艺的优化,选出铁、钛混合精矿,经电炉熔炼生产高钛渣,为钛白粉生产提供原料.尾渣通过选矿降低了铁和碱的含量后,可以大幅拓宽赤泥在建材中的应用途径,提高用量.

  16. Chemical stabilization of metals in mine wastes by transformed red mud and other iron compounds: laboratory tests.

    Science.gov (United States)

    Ardau, C; Lattanzi, P; Peretti, R; Zucca, A

    2014-01-01

    A series of static and kinetic laboratory-scale tests were designed in order to evaluate the efficacy of transformed red mud (TRM) from bauxite refining residues, commercial zero-valent iron, and synthetic iron (III) hydroxides as sorbents/reagents to minimize the generation of acid drainage and the release of toxic elements from multi-contaminant-laden mine wastes. In particular, in some column experiments the percolation of meteoric water through a waste pile, alternated with periods of dryness, was simulated. Wastes were placed in columns together with sorbents/reagents in three different set-ups: as blended amendment (mixing method), as a bed at the bottom of the column (filtration method), or as a combination of the two previous methods. The filtration methods, which simulate the creation of a permeable reactive barrier downstream of a waste pile, are the most effective, while the use of sorbents/reagents as amendments leads to unsatisfactory results, because of the selective removal of only some contaminants. The efficacy of the filtration method is not significantly affected by the periods of dryness, except for a temporary rise of metal contents in the leachates due to dissolution of soluble salts formed upon evaporation in the dry periods. These results offer original information on advantages/limits in the use of TRM for the treatment of multi-contaminant-laden mine wastes, and represent the starting point for experimentation at larger scale.

  17. An Alternative to Clay in Building Materials: Red Mud Sintering Using Fly Ash via Taguchi’s Methodology

    Directory of Open Access Journals (Sweden)

    Suchita Rai

    2013-01-01

    Full Text Available “Red mud” or “bauxite residue” is a highly alkaline waste generated from alumina refinery with a pH of 10.5–12.5 which poses serious environmental problems. Neutralization or its treatment by sintering in presence of additives is one of the methods for overcoming the caustic problem as it fixes nearly all the leachable free caustic soda present in red mud. In the present study, feasibility of reducing the alkaline nature of red mud by sintering using fly ash as an additive via Taguchi methodology and its use for brick production, as an alternative to clay, is investigated. The analysis of variance (ANOVA shows that sintering temperature is the most significant parameter in the process. A pH of 8.9 was obtained at 25–50% of red mud and 50–75% fly ash with water and temperature of . Alternatively 50% of red mud can be mixed with 50% of fly ash with water at temperature of to get a pH of about 8.4. The mechanism of this process has been explained with also emphasis on chemical, mineralogical, and morphological analysis of the sintered red mud. The results would be extremely useful in utilization of red mud in building and construction industry.

  18. The Technological Enhancement of Normally Occurring Radioactive Materials in Red Mud due to the Production of Alumina

    Directory of Open Access Journals (Sweden)

    Maurice O. Miller

    2016-01-01

    Full Text Available This study investigates the level of technological enhancement of normally occurring radioactive materials (TENORM in the red mud waste due to the production of alumina in Jamaica. Technological enhancements factors (TEF were determined for the uranium, thorium, actinium series, their progenies, and the nonseries potassium-40 using gamma spectrometry. The study concluded that bauxite production technologically enhances the uranium progenies Th-234, Pb-214, Bi-214, and Pa-234 and the thorium-232 progenies Ac-228, Pb-212, and Bi-212 in red mud. The actinium series was technologically enhanced, but K-40 and the thorium daughter, Tl-208, were reduced. The spectrometric comparison of Tl-208 (at 510 keV was unexpected since its other photopeaks at 583 keV, 934 keV, and 968 keV were markedly different. An explanation for this anomaly is discussed. An explanation regarding the process of accumulation and fractionation of organically derived phosphate deposits and potassium-feldspar is offered to explain the spectrometric differences between the alumina product and its waste material, red mud.

  19. 赤泥综合利用评述%Review on the Comprehensive Utilization of Red Mud

    Institute of Scientific and Technical Information of China (English)

    王家伟; 吕常胜; 靳学利; 路长远; 贾永真

    2012-01-01

    Red mud or bauxite residue was a waste produced from the alumina industry. There were many production methods of alumina in our country, such as Bayer process, sintering process and mixed combination process, and the types of red mud were various and their characteristics had great difference, which added more difficulty on comprehensive utilization of red mud. The present situation of comprehensive utilization of red mud was summarized, and the idea to produce the glass - ceramics by mixing a certain proportion of red mud from sintering process and mixed combination process with quartz tailings and amounts of quartz was put forward.%赤泥是氧化铝生产过程中排出的固体粉状废弃物。我国生产氧化铝方法比较多,如拜尔法、烧结法和混联法等,导致赤泥的种类多和性质差别较大,增加了赤泥的综合利用的难度。总结了目前赤泥综合利用的现状,并提出用烧结法和联合法赤泥按一定配比混合工业废料石英砂尾泥及适量石英生产微晶玻璃的想法。

  20. Application of Bayer red mud for iron recovery and building material production from alumosilicate residues.

    Science.gov (United States)

    Liu, Wanchao; Yang, Jiakuan; Xiao, Bo

    2009-01-15

    Red mud is a solid waste produced in the process of alumina extraction from bauxite. In this paper, recovery iron from Bayer red mud was studied with direct reduction roasting process followed by magnetic separation, and then building materials were prepared from alumosilicate residues. After analysis of chemical composition and crystalline phase, the effects of different parameters on recovery efficiency of iron were carried out. The optimum reaction parameters were proposed as the following: ratio of carbon powder: red mud at 18:100, ratio of additives: red mud at 6:100, roasting at 1300 degrees C for 110min. With these optimum parameters, total content of iron in concentrated materials was 88.77%, metallization ratio of 97.69% and recovery ratio of 81.40%. Then brick specimens were prepared with alumosilicate residues and hydrated lime. Mean compressive strength of specimens was 24.10MPa. It was indicated that main mineral phase transformed from nepheline (NaAlSiO4) in alumosilicate residues to gehlenite (Ca2Al2SiO7) in brick specimens through X-ray diffraction (XRD) technology. The feasibility of this transformation under the experimental conditions was proved by thermodynamics calculation analysis. Combined the recovery of iron with the reuse of alumosilicate residues, it can realize zero-discharge of red mud from Bayer process.

  1. Review of cadmium transfers from soil to humans and its health effects and Jamaican environment

    Energy Technology Data Exchange (ETDEWEB)

    Lalor, Gerald C. [International Centre for Environmental and Nuclear Sciences, University of the West Indies Mona, Kingston 7 (Jamaica)], E-mail: gerald.lalor@uwimona.edu.jm

    2008-08-01

    Concerns about the effects of cadmium on human health have led to numerous guidelines and regulations limiting its concentrations in soils and food and allowable human intakes. These have socio-economic consequences in terms of land use and the marketing of food. The bauxite soils in Jamaica, which are both aluminium ores and agricultural soils contain orders of magnitude higher than world normal concentrations of cadmium resulting in elevated Cd concentrations in several foodstuffs and significant transfers to humans, which would seem to represent a risk factor for increased mortality and/or morbidity in the local populations. But, as in Shipham and other examples, there is no evidence of cadmium-related human distress. Macro-indicators like life expectancy and median ages of death do not show cadmium related geographical distributions. The present review focuses on the soils and foods and illnesses of high incidence especially cancers and renal disease that have been traditionally associated with cadmium. In view of the remarkable concentrations of cadmium involved in Jamaica, and often contradictory reports in the literature, it appears that much remains to be learned about certain details of cadmium toxicity.

  2. Monitoring of radionuclides in carbon steel blooms produced by EAF process

    Directory of Open Access Journals (Sweden)

    Sofilić T.

    2011-01-01

    Full Text Available Because natural and artificial isotopes in steel might originate from steel scrap or from the residue of the material that was used in the technological process, thus monitoring especially artificial radionuclides 60Co, 137Cs and 192Ir deserve special attention. The analysis by g-spectrometry has been applied to determine the presence of natural isotopes 40K, 226Ra, 232Th and 238U as well as of the artificial isotope 60Co, 137Cs and 192Ir and their activity in the produced steel round blooms in the Steel Mill of CMC Sisak d.o.o. At the same time the content of radionuclides in the other materials (ferroalloys, bauxite, fluorite, lime, coke, graphite electrodes, refractory blocks used in the same steel making process was investigated. The measured values regarding the presence of individual isotopes and their activity in steel were as follows: 40K all values were less than 1.6 Bqkg-1; 232Th all activities values were less than 0.02 Bqkg-1; 226Ra all activities values were less than 0.01 Bqkg-1; 238U all activities values were less than 1.10 Bqkg-1; 60Co all activities values were less than 0.02 Bqkg-1; 192Ir all activities values were less than 0.02 Bqkg-1 and 137Cs all activities values were less than 0.30 Bqkg-1.

  3. Glassceramics frits attainment from industrial solid wastes; Obtencao de fritas vitroceramicas a partir de residuos solidos industriais

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Matheus Chianca

    2006-07-01

    This work studies the residue obtained from the process of aluminum metal extraction activities, a great interest process, because of Brazil own some of the biggest bauxite mineral reserves in all the world. As a useful choice for no residue generation, and a support for environmentally friendly technologies, this work studies the white dross residue (WDR), from the process of aluminum metal reduction by thermal plasma. The phase equilibrium diagram of Al{sub 2}O{sub 3}-Ca O-SiO{sub 2} system was used to calculate the compositions. The WDR were incorporated in a ceramic product without modifying its principal characteristics. The fusion and devitrification treatments were studied. XRD (X-ray diffractometry), SEM (scanning electron microscopy) and FTIR (transformed Fourier infrared) were used to investigate the glass and glassceramic samples. These techniques showed that is possible to get glassceramic with up to 30 mass% of WDR after molten at 1300 deg C and annealed at 900 deg C. In addition, the WDR showed to be a promising material in attainment of crystalline phases in less times of heat treatment for annealing. (author)

  4. Effects of Multiple Soil Conditioners on a Mine Site Acid Sulfate Soil for Vetiver Growth

    Institute of Scientific and Technical Information of China (English)

    LIN Chu-Xia; LONG Xin-Xian; XU Song-Jun; CHU Cheng-Xing; MAI Shao-Zhi; JIANG Dian

    2004-01-01

    A pot experiment was conducted to investigate the effects of various soil treatments on the growth of vetiver grass ( Vetiveria zizanioides (L.) Nash) with the objective of formulating appropriate soil media for use in sulfide-bearing mined areas. An acidic mine site acid sulfate soil (pH 2.8) was treated with different soil conditioner formula including hydrated lime, red mud (bauxite residues), zeolitic rock powder, biosolids and a compound fertilizer. Soils treated with red mud and hydrated lime corrected soil acidity and reduced or eliminated metal toxicity enabling the establishment of vetiver grass.Although over-liming affected growth, some seedlings of vetiver survived the initial strong alkaline conditions. Addition of appropriate amounts of zeolitic rock powder also enhanced growth, but over-application caused detrimental effects. In this experiment, soil medium with the best growth performance of vetiver was 50 g of red mud, 10 g of lime, 30 g of zeolitic rock powder and 30 g of biosolids with 2000 g of mine soils (100% survival rate with the greatest biomass and number of new shoots), but adding a chemical fertilizer to this media adversely impacted plant growth. In addition, a high application rate of biosolids resulted in poorer growth of vetiver, compared to a moderate application rate.

  5. Institutional arrangements for the reduction of proliferation risks formulation, evaluation, and implementation of institutional concepts. Appendices

    Energy Technology Data Exchange (ETDEWEB)

    1979-12-01

    The purpose of this supporting analysis is to provide a foundation for developing a model, an international or multinational institution capable of accomodating the back end of the fuel cycle, while meeting US nonproliferation goals. The analysis is based on a review of selected, defunct and extant institutions which, although not necessarily concerned with nonproliferation, have faced a trade-off between acceptability and effectiveness in meeting their objectives. Discussion of the various institutions is divided into three categories: international organizations, multinational consortia, and cartels or producer associations. Examples of international organizations include the International Seabed Authority, Intelsat, the United Nations and the International Atomic Energy Agency (IAEA). The International Seabed Authority is discussed. Multinational consortia are organizations that have been developed primarily to meet common commercial objectives. Membership includes at least three member nations. Examples include the Scandinavian Airline System (SAS), URENCO, Unilever, Royal Dutch Shell, Eurochemic, Eurodif, Euratom, European Coal and Steel Community, and Serena. Cartels or producer associations are multinational agreements that restrict market forces; viz, production, market share, customers or prices. Examples include the Intergovernmental Council of Copper Exporting Countries (CIPEC), the Organization of Petroleum Exporting Countries (OPEC), and the Fifth International Tin Agreement (ITA), as well as agreements governing diamonds and uranium, bauxite and coffee. OPEC, CIPEC and ITA are discussed.

  6. Dextrocardia with situs solitus and inversion apex-basis axis in lesser anteater (Tamandua tetradactyla: case report

    Directory of Open Access Journals (Sweden)

    V.L.C. Pinheiro

    2014-02-01

    Full Text Available Dextrocardia is a rare cardiac anomaly where the heart is situated on the right antimeres of the thorax. This study had the objective of describing a case of dextrocardia with situs solitus and apex-basis axis inversion in a lesser anteater (Tamandua tetradactyla between five evaluated animals, all from the area of Mine Bauxite - Paragominas - Para. The arterial system was filled with contrasted latex and the animals were fixed with 10% formaldehyde and a posterior dissection was done. The heart of an animal was found in right antimere with inversion of the base-apex axis. The right atrium was more developed then the left and the pulmonary veins arrived directly in the left ventricle. The main vases of the base were identified with some topographic alterations resulting in: aorta dorsal to the cava caudal vein, pulmonary artery dorsal and cranial to aorta, pulmonary veins ventral to the pulmonary artery, cava caudal vein in ventral plain and cava cranial vein in dorsal plan in relation to the other vessels. Internally there were four cardiac chambers, with absence of septal communication.

  7. Determination of the apparent porosity level of refractory concrete during a sintering process using an ultrasonic pulse velocity technique and image analysis

    Directory of Open Access Journals (Sweden)

    LJUBICA M. PAVLOVIĆ

    2010-03-01

    Full Text Available Concrete which undergoes a thermal treatment before (pre-casted concrete blocks and during (concrete embedded in-situ its life-service can be applied in plants operating at high temperature and as thermal insulation. Sintering is a process which occurs within a concrete structure in such conditions. Progression of sintering process can be monitored by the change of the porosity parameters determined with a nondestructive test method - ultrasonic pulse velocity and computer program for image analysis. The experiment has been performed on the samples of corundum and bauxite concrete composites. The apparent porosity of the samples thermally treated at 110, 800, 1000, 1300 and 1500 C was primary investigated with a standard laboratory procedure. Sintering parameters were calculated from the creep testing. The loss of strength and material degradation occurred in concrete when it was subjected to the increased temperature and a compressive load. Mechanical properties indicate and monitor changes within microstructure. The level of surface deterioration after the thermal treatment was determined using Image Pro Plus program. Mechanical strength was estimated using ultrasonic pulse velocity testing. Nondestructive ultrasonic mea¬surement was used as a qualitative description of the porosity change in specimens which is the result of the sintering process. The ultrasonic pulse velocity technique and image analysis proved to be reliable methods for monitoring of micro-structural change during the thermal treatment and service life of refractory concrete.

  8. Preliminary Assessment of Non-Fuel Mineral Resources of Afghanistan, 2007

    Science.gov (United States)

    ,

    2007-01-01

    Introduction Afghanistan has abundant mineral resources, including known deposits of copper, iron, barite, sulfur, talc, chromium, magnesium, salt, mica, marble, rubies, emeralds, lapis lazuli, asbestos, nickel, mercury, gold and silver, lead, zinc, fluorspar, bauxite, beryllium, and lithium (fig. 1). Between 2005 and 2007, the U.S. Agency for International Development (USAID) funded a cooperative study by the U.S. Geological Survey (USGS) and the Afghanistan Geological Survey (AGS) to assess the non-fuel mineral resources of Afghanistan as part of the effort to aid in the reconstruction of that country. An assessment is an estimation or evaluation, in this instance of undiscovered non-fuel mineral resources. Mineral resources are materials that are in such form that economic extraction of a commodity is currently or potentially feasible. In this assessment, teams of scientists from the USGS and the AGS compiled information about known mineral deposits and then evaluated the possible occurrence of undiscovered deposits of all types. Quantitative probabilistic estimates were made for undiscovered deposits of copper, mercury, rare-earth elements, sulfur, chromite, asbestos, potash, graphite, and sand and gravel. These estimates were made for undiscovered deposits at depths less than a kilometer. Other deposit types were considered and discussed in the assessment, but quantitative estimates of numbers of undiscovered deposits were not made. In addition, the assessment resulted in the delineation of 20 mineralized areas for further study, of which several may contain resources amenable to rapid development.

  9. Matures fields of Northeast of Brazil: who to work with and renew them; Rejuvenescimento dos campos maduros de Alagoas sob a otica de intervencao em pocos

    Energy Technology Data Exchange (ETDEWEB)

    Payao, Edson da C.; Fernandes, Emanoel F. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    There are mature fields in Alagoas, such as Furado and Pilar, discovered in 1969 and 1981, respectively. Drilling was resumed in 1998 and the Well Intervention Team was called upon to meet the newfound challenges: pronounced well deviation of up to 75 deg, a horizontal well, and the difficulties that ensue; to perform hydraulic fracture at deep horizons, with high pressure on the surface (in excess of 8,000 psi), premature screen out, tortuosity, secondary fractures (fissuring), etc. These setbacks can be overcome by employing: calibration test with high output; bauxite slugs; sand to decrease filtering; high performance gel. Deep damage in areas where there is water contact inside the well. Problems were overcome using TCP with extreme under balance (EUB) to bypass perforation damage and prevent the sort of damage caused by completion activity. Multidisciplinary approach towards determining onshore production rig interventions; these must be carried out with zeal and an eye to new opportunities, thus underscoring the importance of the data collected onsite. New equipment and completion methods. Upgrading and newer procedures. The yield curve rose once again, bringing renewed enthusiasm and resulting in highly attractive costs for PETROBRAS. (author)

  10. Pollution control. sulphur recovery from industrial effluents. design of reactor

    Energy Technology Data Exchange (ETDEWEB)

    Venkatram, T.; Pachaiyappan, V.

    1978-05-01

    In a process for the recovery of sulfur from a refinery gas containing 10.8-17.8% hydrogen sulfide, 13.4-27.6% hydrogen, 19.7-23.6% methane, and 34.2-40.7% C/sub 2/-C/sub 5/ hydrocarbons, the hydrogen sulfide is selectively absorbed in monoethanol amine (MEA) solution. The hydrogen sulfide gas is stripped off from the MEA solution and sent to a furnace chamber with air at an air/hydrogen sulfide ratio of 2.5 by vol to convert 33% of the hydrogen sulfide to sulfur dioxide and the hydrocarbons to carbon dioxide and water. The product gases are cooled from 1200/sup 0/C to a final temperature of 232/sup 0/C, and any sulfur formed in the furnace is condensed and drained to a sulfur pit. The outlet gases from the final pass are routed to the Claus converter in which hydrogen sulfide and sulfur dioxide react over a bauxite catalyst to form elemental sulfur. Noncondensable gases are sent to a second converter for completion of the reaction. Any remaining noncondensable gases are sent to a coalescer to recover entrained sulfur and then to an incinerator. Design of the Claus converter and of the shell-and-tube heat exchanger used for cooling the gases from the furnace and for steam generation is illustrated for various operating conditions. Diagrams.

  11. Implementation of industrial waste ferrochrome slag in conventional and low cement castables: Effect of calcined alumina

    Directory of Open Access Journals (Sweden)

    Pattem Hemanth Kumar

    2014-12-01

    Full Text Available A new class of conventional and low-cement ferrochrome slag-based castables were prepared from 40 wt.% ferrochrome slag and 45 wt.% calcined bauxite. Rest fraction varied between high alumina cement (HAC acting as hydraulic binder and calcined alumina as pore filling additive. Standard ASTM size briquettes were prepared for crushing and bending strengths evaluation, and the samples were then subjected to firing at 800, 1100 and 1300 °C for a soaking period of 3 h. The microstructure and refractory properties of the prepared castables have been investigated using X-ray diffraction (XRD, scanning electron microscopy (SEM, cold crushing strength, modulus of rupture and permanent linear changes (PLCs test. Castables show good volume stability (linear change <0.7% at 1300 °C. The outcomes of these investigations were efficacious and in accordance with previously reported data of similar compositions. High thermo-mechanical and physico-chemical properties were attained pointing out an outstanding potential to increase the refractory lining working life of non-recovery coke oven and reheating furnaces.

  12. Intensifying digestion of diaspore and separation of alumina and silica

    Institute of Scientific and Technical Information of China (English)

    李小斌; 彭志宏; 刘桂华; 周秋生

    2003-01-01

    It was found that there lies a linear relationship among the thermodynamic data of complicate inorganic compounds with similar components. A method for estimating the thermodynamic data of complicate compound and a thermodynamic database involving alumina production were developed. It was found that the alumina digestion rate of activated diasporic bauxite by means of heat field increased much due to the structure aberration, i.e, from perfect structure to unstable corundum. The results from thermodynamic calculation and experiments showed that it was feasible for desilication at atmospheric pressure, and the effects on equilibrium concentration of SiO2 included temperature, mole ratio of Na2O/Al2O3 (αk), caustic and Na+ concentration. The technology of desilication of green liquor at atmosphere and separation of alumina and silica in aluminate solution with high concentration were established. The reaction activity of compounds containing silica and the converting law among compounds were studied, and the prototype technology of desilication products by hydrotreatment was also developed.

  13. Technological Proposals for Recycling Industrial Wastes for Environmental Applications

    Directory of Open Access Journals (Sweden)

    Isabel Romero-Hermida

    2014-08-01

    Full Text Available A two-fold objective is proposed for this research: removing hazardous and unpleasant wastes and mitigating the emissions of green house gasses in the atmosphere. Thus, the first aim of this work is to identify, characterize and recycle industrial wastes with high contents of calcium or sodium. This involves synthesizing materials with the ability for CO2 sequestration as preliminary work for designing industrial processes, which involve a reduction of CO2 emissions. In this regard, phosphogypsum from the fertilizer industry and liquid wastes from the green olive and bauxite industries have been considered as precursors. Following a very simple procedure, Ca-bearing phosphogypsum wastes are mixed with Na-bearing liquid wastes in order to obtain a harmless liquid phase and an active solid phase, which may act as a carbon sequestration agent. In this way, wastes, which are unable to fix CO2 by themselves, can be successfully turned into effective CO2 sinks. The CO2 sequestration efficiency and the CO2 fixation power of the procedure based on these wastes are assessed.

  14. Updated Life-Cycle Assessment of Aluminum Production and Semi-fabrication for the GREET Model

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Qiang [Argonne National Lab. (ANL), Argonne, IL (United States); Kelly, Jarod C. [Argonne National Lab. (ANL), Argonne, IL (United States); Burnham, Andrew [Argonne National Lab. (ANL), Argonne, IL (United States); Elgowainy, Amgad [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-01

    This report serves as an update for the life-cycle analysis (LCA) of aluminum production based on the most recent data representing the state-of-the-art of the industry in North America. The 2013 Aluminum Association (AA) LCA report on the environmental footprint of semifinished aluminum products in North America provides the basis for the update (The Aluminum Association, 2013). The scope of this study covers primary aluminum production, secondary aluminum production, as well as aluminum semi-fabrication processes including hot rolling, cold rolling, extrusion and shape casting. This report focuses on energy consumptions, material inputs and criteria air pollutant emissions for each process from the cradle-to-gate of aluminum, which starts from bauxite extraction, and ends with manufacturing of semi-fabricated aluminum products. The life-cycle inventory (LCI) tables compiled are to be incorporated into the vehicle cycle model of Argonne National Laboratory’s Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) Model for the release of its 2015 version.

  15. Hungary.

    Science.gov (United States)

    1992-12-01

    Hungary is a country of 93,000 sq km with 10 million inhabitants, of whom 99% are literate. Its constitution was written on August 20m 1949, substantially revised in 1989, and amended in 1990. The terrain is flat with low mountains in the North and Northeast and north of Lake Balaton, with a climate which is temperate. Primarily Magyar is spoken by the 92% population of Magyar, though Gypsies, Germans, Slovaks, Jews, southern Slavs, and other ethnic groups are also resident. Inhabitants are variously of Roman Catholic, Calvinist, Lutheran, and other faiths. Life expectancy is 67-75 years. GDP is $35 billion, declining at a rate of 3%. Per capita income is $3300. The country's natural resources include fertile land, bauxite, and brown coal. Meat, corn, wheat, potatoes, sugar beets, vegetables, fruits, sunflower seeds, machinery, buses and other transportation equipment; precision and measuring equipment; textiles; medical instruments; and pharmaceutical are areas of economic production. Energy, raw materials, machinery, and transportation equipment are imported, and machinery, buses, and other transportation equipment; medical instruments; pharmaceutical; textiles; other consumer manufactures; and agricultural products are exported. In-depth information is also given on the people and history, government and principal officials, political conditions, the economy, defense, foreign relations, relations with the U.S., and names of principal U.S. officials in the country.

  16. Hollow proppants and a process for their manufacture

    Science.gov (United States)

    Jones, Arfon H.; Cutler, Raymond A.

    1985-01-01

    Hollow, fine-grained ceramic proppants are less expensive and improve fracture control when compared to conventional proppants (dense alumina, mullite, bauxite, zirconia, etc.). Hollow proppants of the present invention have been fabricated by spray drying, followed by sintering in order to obtain a dense case and a hollow core. These proppants generally have high sphericity and roundness (Krumbein sphericity and roundness greater than 0.8), have diameters on average between 2250 and 125 .mu.m, depending on proppant size required, and have strength equal to or greater than that of sand. The hollow core, the size of which can be controlled, permits better fracture control in hydraulic fracturing treatments since the proppant can be transported in lower viscosity fluids. Hollow proppants produced at the same cost/weight as conventional proppants also provide for lower costs, since less weight is required to fill the same volume. The fine-grained (preferably less than 5 .mu.m in diameter) ceramic case provides the strength necessary to withstand closure stresses and prevent crushing.

  17. Tertiary weathering profiles in central Nigeria as indicators of paleoenvironmental conditions

    Science.gov (United States)

    Zeese, Reinhard

    1996-05-01

    In central Nigeria the Fluviovolcanic Series of the Jos Plateau are composed by deeply weathered volcanic rocks and sediments. The sequence is often capped by ferricretes. Ferricretes, remains of former soils, are also intercalated in the series. Profile sections between two ferricretes are deep (> 10 m). The repeated saprolite/solum sequence sometimes exceeds 100 m. It can be separated into a lower section without bauxitisation, but often with total bleaching of the saprolite, a middle section with bauxite and hematite in the saprolite and an upper kaolinitic section with hematite and goethite. Bleaching by total removal of Fe 2+ and bauxitisation by total desilification are both indicators of wet and hot climates with a high biomass production. In the first case the groundwater was permanently high, in the latter a well drained fluctuating groundwater can be assumed. Changing groundwater conditions may be the result of plateau uplift. Paleoenvironmental changes are, thus, reflected in relatively datable paleosols. Undatable paleosoils with comparable characteristics on the planation surfaces of Central and Northeast Nigeria also result from paleoenvironmental conditions. Consequently, concepts of landscape evolution must take into account changing environments.

  18. Variáveis biométricas da cana-de-açúcar fertilizada com resíduos orgânico e industrial e irrigada com água servida e potável Biometric variable of sugar cane fertilized with organic and industrial residues irrigated with potable and wastewater

    Directory of Open Access Journals (Sweden)

    Fabio O. de Nobile

    2011-02-01

    Full Text Available O uso agrícola de resíduos orgânicos e industriais é uma alternativa de aproveitamento como fertilizante e fonte de matéria orgânica ao solo. Neste sentido, o objetivo deste trabalho foi avaliar o uso do composto de lixo e biofertilizante como fonte de nutrientes, e o resíduo do processamento da bauxita como corretivo da acidez do solo, para a cultura da cana-de-açúcar (cana-planta, irrigada com água potável e servida. Para tanto foi conduzido experimento em vaso, utilizando-se de solo Argissolo Vermelho-Amarelo distrófico, cultivado com a variedade RB855536. Foram avaliadas variáveis biométricas da planta, tais como: altura de plantas, diâmetro do colmo, perfilhamento, número de folhas, matéria seca de raiz e parte aérea. Os dados obtidos evidenciaram que a qualidade da água de irrigação, potável ou servida, não influenciou as variáveis avaliadas. A aplicação de composto de lixo e de biofertilizante constituiu-se numa fonte eficiente de nutrientes para as plantas de cana-de-açúcar, mas é necessária a aplicação adicional de fertilizantes para a obtenção de produção de colmos, similar ao do tratamento com adubação mineral convencional. Já o resíduo do processamento da bauxita mostrou-se eficiente na correção da acidez, apresentando as variáveis físicas semelhantes ao tratamento com adubação mineral, com exceção da matéria seca de raiz.The agricultural use of organic and industrial residues is an alternative of exploitation with fertilization and source of organic matter to the soil. In this direction, the objective of this research was to evaluate the use of the urban solid waste and biofertilizer as nutrient source, and residue of the bauxite processing as agricultural liming materials of the soil for sugar cane (cane plant and culture yields, irrigated with potable water and wastewater. For in such an experiment in vase was lead, under Alfisol soil, cultivated with the variety RB855536. It had

  19. IMPACTO DE ÁGUAS DE IRRIGAÇÃO E RESÍDUOS DE DIFERENTES ORIGENS NOS TEORES DE MICRONUTRIENTES NO SOLO E NA CANA-DE AÇÚCAR

    Directory of Open Access Journals (Sweden)

    Reginaldo Itiro Muraishi

    2012-05-01

    Full Text Available O objetivo deste trabalho foi avaliar o uso do composto de lixo e biofertilizante como fonte de nutrientes, e oresíduo do processamento da bauxita como corretivo da acidez do solo, irrigada com água potável e servida. Para tanto foiconduzido experimento em vaso, utilizando-se solo Argissolo Vermelho Amarelo, sendo avaliadas as concentraçõesmacronutrientes no solo (Cu, Fe, Mn e Zn na camada de 0-20 cm e nas folhas de cana-de-açúcar (B, Cu, Fe, Mn e Zn. Osdados obtidos evidenciaram que a adubação com biofertilizante aumentou significativamente os teores de Cu e Zn no solo(0,56 e 0,63 mg dm-3, respectivamente, a aplicação de resíduo do processamento da bauxita elevou as concentrações demanganês, não foram observados mudanças para Fe. Já nas folhas de cana-de-açúcar o uso de resíduo do processamento dacana-de-açúcar elevou os teores de todos os micronutrientes, a aplicação de biofertilizante e composto de lixo elevou osteores de Cu nas folhas (0,80 e 1,00 mg dm-3 respectivamente entretanto houve uma redução do teor de Mn (84,66 e 89,66mg dm-3 respectivamente. A qualidade da água de irrigação, potável ou servida, não influenciou as concentrações demacronutrientes no solo, bem como os teores desses elementos na planta.The agricultural use of organic residues and industrial is an alternative of exploitation with fertilizationand source organic matter to the soil. In this direction, the objective of this research was to evaluate the use of the urbansolid waste and biofertilizer as nutrient source, and residue of the bauxite processing as agricultural liming materials of thesoil, irrigated with potable water and wastewater. For in such a way experiment in vase was lead, under soil Alfisol, beingevaluated the micronutrient concentrations in the soil (Cu, Fe, Mn and Zn in the layer of 0-20 cm and leaves of sugar cane(Cu, Fe, Mn and Zn. The gotten data had evidenced the fertilization with biofertilizer increased texts of Cu

  20. MICRONUTRIENTS IN SOIL IRRIGATED OF WASTE WATER SERVED AND THE SUGAR CANE FERTILIZED WITH ORGANIC AND INDUSTRIAL RESIDUES = MICRONUTRIENTES NO SOLO IRRIGADO COM ÁGUA SERVIDA E NA PLANTA DE CANA-DE-AÇÚCAR FERTILIZADA COM RESÍDUOS ORGÂNICOS E INDUSTRIAIS

    Directory of Open Access Journals (Sweden)

    Fabio Olivieri de Nobile

    2013-01-01

    Full Text Available Population growth, with consequent demands for consumer goods and increased industrial development generate significant amounts of waste and increase the indiscriminate use of water. The environmental impact caused by the improper disposal of waste in the environment, causes great difficulty to control, implying high costs in its remediation. The agricultural use of organic and industrial residues is an alternative of exploitation with fertilization and source organic matter to the soil. In this direction, the objective of this research was to evaluate the use of the urban solid waste and biofertilizer as nutrient source, and residue of the bauxite processing as agricultural liming materials of the soil, irrigated with potable water and wastewater. The experiment was conducted in vase was lead, under soil Alfisol, being evaluated the micronutrient concentrations in the soil and leaves of sugar cane (Cu, Fe, Mn and Zn. The gotten data had evidenced the fertilization with biofertilizer increased texts of significantly Cu and Zn in the soil (409% e 520% mg.dm-3, respectively, the application of residue of the processing of the bauxite raised the manganese concentrations, had not been observed changes for Fe. Already in sugar cane leaves the use of residue of the processing the sugar cane raised texts of all the micronutrients, the application of biofertilizer and made up of urban solid waste raised texts of Cu in leaves (0.80 and 1.00 mg.dm-3 respectively however had a reduction of the text of Mn (124.66 and 84.66 mg.dm-3 respectively. The quality of irrigation water, drinking or served, did not influence the micronutrients concentrated in the soil as well as the contents of these elements in the plant. = O crescimento populacional, com as consequentes demandas por bens de consumo, e o aumento do desenvolvimento industrial geram quantidades expressivas de resíduos e aumento do uso indiscriminado de água. O impacto ambiental originado pela disposi

  1. 铁尾矿贝利特硫铝酸盐水泥的制备及性能研究%Preparation of Belite-sulphoaluminate Cement with Iron Tailings and its Properties

    Institute of Scientific and Technical Information of China (English)

    郑永超; 刘艳军; 李德忠; 李青

    2013-01-01

    以首云矿业股份有限公司铁尾矿、低品位矾土等为原料制备铁尾矿贝利特硫铝酸盐水泥,为铁尾矿的高附加值利用探索新的途径.研究结果表明:在生料中铁尾矿、矾土、煅烧石灰石、Al2 O3、CaSO4·2H2O的配比为10∶ 17∶ 48∶ 15∶10,煅烧温度为1 350℃,煅烧时间为20 min条件下,可制备出矿物成分以C4A3S、C2S、C4AF为主,f-CaO含量小于1.5%的铁尾矿贝利特硫铝酸盐水泥熟料.向该熟料中配入与其质量比均为8%的天然石膏和石灰石制成水泥,再按胶砂比为1∶3、水胶比为0.6制成水泥胶砂,胶砂的3d抗压强度达38.1 MPa、28 d抗压强度达52.5 MPa.%With iron tailings and low grade bauxite from Shouyun Mining Company as raw materials,the belite-sulphoaluminate cement clinker was prepared,which proposes a new way for exploring the high added value of iron tailings.The results showed that with the ratio of iron tailings,bauxite,calcined limestone,Al2 O3,CaSO4 · 2H2O of 10∶ 17∶ 48∶ 15∶10 in the raw meal,and at the calcination temperature of 1 350 ℃ for 20 min,belite-sulphoaluminate cement clinker with major components of C4A3S,C2S,C4AF and f-CaO content of less than 1.5% was prepared.Then,natural gypsum and limestone were added into the clinker with the quality ratio of 8% to prepare the cement raw meal.With the cement-sand ratio of 1∶3,and water-cement ratio of 0.6,the cement-mortar product reached the compressive strength of 38.1 MPa,at 3 d,and 52.5 MPa at 28 d.

  2. Iron's Role in Aluminum: A Powder Metallurgy and Sustainability Approach

    Science.gov (United States)

    Saller, Brandon Dale

    The family of Al-Fe alloys is both scientifically and technologically interesting for several reasons. First, the low equilibrium solid solubility (0.03 at.%) and diffusivity of Fe in Al suggest that the alloys containing these two elements should be thermally stable. Many studies have tried to extend this low solubility value via non-equilibrium processing routes. Second, published results suggest that there is a range of intermetallic phases, including the metastable orthorhombic Al6Fe and the equilibrium monoclinic Al13Fe4, for example, the formation of which depends on solidification and subsequent processing conditions. Third, from a sustainability standpoint, both Al and Fe are present in bauxite (aluminum ore), however up to 40 wt.% Fe-oxide present in bauxite is discarded as a waste product, creating red mud pits. In order to understand the multiple facets and implications of iron's role in aluminum, a systematic investigation was performed into the precipitates that form as a function of thermal exposure and their subsequent effect on the tensile behavior of the alloy. In this study, Al-2at.% Fe and Al-5at.% Fe powders were synthesized via helium gas atomization and argon gas atomization, respectively. Cooling rates upwards of 106 K/s were achieved resulting in an intermetallic-free starting structure. Powders were subsequently severely plastically deformed via either cryomilling or high-pressure torsion to obtain nanostructured/ultrafine-grained powder or a consolidated specimen, respectively. Characterization via electron microscopy established a map of the powder microstructure as a function of atomization cooling rate. In addition, electron backscatter diffraction revealed a large number of low-angle grain boundaries, which influenced nucleation and precipitation of the metastable Al6Fe phase. X-ray diffraction and atom probe tomography results provide the most comprehensive evidence to date of forcing of 2at.% Fe into solution with the Al matrix via

  3. Geochemical and mineralogical constraints on the distribution and enrichment of the rare earth elements during pedogenesis and tropical weathering

    Science.gov (United States)

    Hardy, Liam; Smith, Martin; Moles, Norman; Marsellos, Antonios

    2015-04-01

    Current European manufacturing relies heavily on imports from the USA & China for unprocessed rare earth elements (REEs) and rare earth oxides (REOs). It has been suggested that the EU holds viable reserves of REEs that, with adequate research, could satisfy 10% of EU industrial demand, by the recycling of mine waste from bauxite production (red muds) alone (Deady, E. (BGS), 2014). Focus has been turned to the potential for Mount Weld type laterite deposits being exploited in the EU, but limited exploration and understanding of EU laterite (& paleo laterite) formations currently makes them unattractive to investment. Although previously researched, the full range of factors influencing the transition of rare earth (primarily lanthanide series, Y & Sc) elements between mineral and clay phases in allochthonous soils, saprolites and laterites is not fully understood, especially in present and Paleo-European environments (Herrington, Boni, Skarpelis, & Large, 2007) (Deady, E. (BGS), 2014) but several deposits globally are suggested to have formed at economically viable concentrations due to this secondary remobilisation & transition from mineral to clay phase and subsequent seasonal leaching and evaporation system, to form depositional buffer zones other than the soil base. (Hoatson, Jaireth, & Miezitis, 2011) (Berger, Janots, Gnos, Frei, & Bernier, 2014). This project intends to use new techniques in sequential extractions, ICP-MS, Quantitative XRD & SEM analysis to expand current knowledge around lateritic & allochtonous ore forming, & weathering processes. Heavy REE content and mineralogical variations in clays will be examined, with examples from a selection of profiles across Southern Europe (and potentially paleo soils from Scandinavia) to define the main influencing factors on REE concentration. Are the specific sites enriched simply by the nature of their source rock (protolith), by the soil formation (pedogenesis), or by biogenic & meteorological factors

  4. Recovery Act: Innovative CO2 Sequestration from Flue Gas Using Industrial Sources and Innovative Concept for Beneficial CO2 Use

    Energy Technology Data Exchange (ETDEWEB)

    Dando, Neal; Gershenzon, Mike; Ghosh, Rajat

    2012-07-31

    . Incorporation of the laboratory results showed that for the application at the aluminum smelter, the in-duct scrubber system is more economical than traditional methods. However, the reverse is true for the refinery case, where the bauxite residue is not effective enough as a sequestrant, combined with challenges related to contaminants in the bauxite residue accumulating in and fouling the scrubber absorbent. Sensitivity analyses showed that the critical variables by which process economics could be improved are enzyme concentration, efficiency, and half-life. At the end of the first part of the Phase 2 project, a gate review (DOE Decision Zero Gate Point) was conducted to decide on the next stages of the project. The original plan was to follow the pre-testing phase with a detailed design for the field testing. Unfavorable process economics, however, resulted in a decision to conclude the project before moving to field testing. It is noted that CO2 Solutions proposed an initial solution to reduce process costs through more advanced enzyme management, however, DOE program requirements restricting any technology development extending beyond 2014 as commercial deployment timeline did not allow this solution to be undertaken.

  5. 印尼矿业法规政策变化对中国的影响研究%Research on the Effects of Changes of Mining Laws and Policies of Indonesia on China

    Institute of Scientific and Technical Information of China (English)

    郑娟尔; 袁国华; 王世虎

    2014-01-01

    印度尼西亚矿产资源丰富,是我国镍矿、铝土矿的主要进口国,也是我国LNG的潜在进口来源大国。近年来,印尼在矿产品出口和矿业投资方面出台了很多法规政策,尤其是原矿禁止出口政策对我国造成了一定的影响。下一步,我国要加快在印尼建设矿业加工园区或冶炼厂,增加从澳大利亚、印度、菲律宾等进口铝和镍,同时,积极化解产能过剩,减少对印尼矿产资源的依赖。%Indonesia is rich in mineral resources, which is not only the main destination for nickel ore bauxite import of China, but also China's LNG potential source of import country. In recent year, many regulations and policies concerning mineral exports and mining investment have been published. Above all, the export bans policy of crude ore has produced impacts on China. In response to this, this paper introduces some measures required for improving this situation. Firstly, we should speed the construction pace of mining processing park or smeltery in Indonesia;and increase imports of aluminum and nickel from Australia, India and Philippines. At the same time, we should resolve excess capacity and reduce our dependence on mineral resources in Indonesia.

  6. Advances in chemical and physical properties of electric arc furnace carbon steel slag by hot stage processing and mineral mixing

    Energy Technology Data Exchange (ETDEWEB)

    Liapis, Ioannis, E-mail: iliapis@sidenor.vionet.gr [AEIFOROS SA, 12th km Thessaloniki-Veroia Rd, PO Box 59, 57008 Ionia, Thessaloniki (Greece); Papayianni, Ioanna [Laboratory of Building Materials, Department of Civil Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

    2015-02-11

    Highlights: • Addition of 10% perlite decreases specific weight of the slag by approx. 7.5%. • Slag-crucible interaction and thin coating layer result in variations in XRF. • XRD shows high glass content and smaller crystalline sizes due to rapid cooling. • SEM shows higher homogeneity and lower crystallisation for SiO{sub 2}/CaO-rich samples. • Physical properties (LA, PSV, AAV) of modified slag show limited deterioration. - Abstract: Slags are recognised as a highly efficient, cost effective tool in the metal processing industry, by minimising heat losses, reducing metal oxidation through contact with air, removing metal impurities and protecting refractories and graphite electrodes. When compared to natural aggregates for use in the construction industry, slags have higher specific weight that acts as an economic deterrent. A method of altering the specific weight of EAFC slag by hot stage processing and mineral mixing, during steel production is presented in this article. The method has minimal interference with the production process of steel, even by limited additions of appropriate minerals at high temperatures. Five minerals are examined, namely perlite, ladle furnace slag, bauxite, diatomite and olivine. Measurements of specific weight are accompanied by X-ray diffraction (XRD) and fluorescence (XRF) analysis and scanning electron microscopy spectral images. It is also shown how altering the chemical composition is expected to affect the furnace refractory lining. Additionally, the process has been repeated for the most suitable mix in gas furnace and physical properties (FI, SI, LA, PSV, AAV, volume stability) examined. Alteration of the specific weight can result in tailoring slag properties for specific applications in the construction sector.

  7. Alternative granular media for the metal casting industry. Final report, September 30, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Guichelaar, P.J.; Ramrattan, S.N.; Tieder, R.E. [Michigan Technological Univ., Houghton, MI (United States)

    1995-09-01

    Silica sand for foundry use is inexpensive to purchase, readily transported and widely available. As a result, it is universally used. However, three factors are becoming increasingly significant as more environmental regulations are promulgated. First, the disposal of waste foundry sand has become an excessively burdensome cost. Second, the phase changes which occur in the silica structure on heating and cooling cause thermal breakdown of the sand into smaller unusable fractions. Third, silica is a relatively weak mineral. Alternatives to silica sand which can withstand the rigors of repetitive reuse must be seriously evaluated as a way to control production costs of the domestic metal casting industry. Chromite sands, olivine sands and carbon sands have each been successfully used to solve operating problems and thus have developed their specific niches in the foundry materials inventory. However, there are several other materials that are candidates for replacing silica sand, such as fused alumina, sintered bauxite and sintered oil well proppants. These media, and others that are generically similar, are manufactured for specific purposes. Compositions and shapes could be readily tailored for used in a metal casting environment of total recycling and materials conservation. This study examines materials that are readily available as alternatives to silica sand from a functionality perspective and a cost perspective. Some of the alternative materials are natural and others are synthetic and thus referring to them as ``sands`` has the potential to cause confusion; the generic term ``granular medium`` is used in this study to mean any material that could functionally substitute for silica sand in the foundry process.

  8. Efecto de la adición de lodos rojos como inhibidores de la corrosión de acero embebido en mortero

    Directory of Open Access Journals (Sweden)

    Díaz, B.

    2008-06-01

    Full Text Available The red mud (RM is the main residue of the Bayer Process, in which alumina is extracted from bauxite. Due to huge amount produced worldwide (84.1x109 kg/year and their high alkaline character, RM represents an important environmental problem in areas where the industry is implanted. RM particles in alkaline solutions are ionised with hydroxyl groups that can anchorage to a metallic surface. This feature suggests the possibility of using RM as an inhibitor for steel in alkaline medium. So a possible solution for these residues, as additive in reinforcing concrete, is presented in this study. The experimental results prove samples with RM do not present corrosion in spite of the high amount of chloride ions.

    Los lodos rojos (LR son el principal residuo del Proceso Bayer, en el cual se extrae alúmina a partir de bauxita. Debido a las enormes cantidades generadas (84,1 millones de toneladas en 2000, en el mundo y a su elevado carácter alcalino, suponen un grave problema medioambiental en las zonas donde la industria está implantada. Las partículas de LR en medio alcalino se encuentran cargadas, conteniendo grupos hidroxilos capaces de anclarse a la superficie metálica. Esta característica hace que dichas partículas se presenten como posibles inhibidores de la corrosión de acero en medio alcalino. En este trabajo se presenta una posible vía para dar salida a estos residuos, empleándolos como aditivos en hormigón armado. Los resultados que se muestran en este estudio revelan que las probetas que contienen LR en su composición no presentan ningún signo de corrosión, a pesar del alto contenido nominal en cloruros.

  9. Energy resources of Pacific Coast of Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Bueno Salazar, R.

    1986-07-01

    Despite failure of modest exploration efforts to yield commercial hydrocarbon production in the Choco-Pacific coastal basin of Colombia, recent geophysical, geochemical, and surface geologic investigations indicate a potential for petroleum accumulations, which could be related to fields located on the western basins of Ecuador that in fact constitute an extension of the Colombian Pacific geologic scheme. The Choco-Pacific coastal basin of Colombia covers an area of approximately 70,000 km/sup 2/, of which 14,000 km/sup 2/ lies offshore. The structural style of this area corresponds to a convergent plate basin created over folded oceanic sediments and adjacent to the subduction zone. Such a framework could be conducive to an attractive array of potential hydrocarbon-bearing traps. Geochemical knowledge of potential source rocks of Cretaceous and early Tertiary age confers an added attraction to the area. Most evaluations reveal kerogen-rich, gas-prone organic matter. Nevertheless, the existence of oil seeps from Cretaceous outcrops could indicate sufficient thermal maturity for oil generation. Adequate reservoirs could be found in sandy or calcareous rocks of late Eocene to Oligocene age, predominantly of marine origin with an estimated thickness exceeding 20,000 ft. Colombia has been one of the leading world producers of gold and platinum, mostly derived from the vast alluvial cover of the onshore area of the basin. In rocks cropping out in the Western Cordillera (eastern margin of the basin), deposits of potentially commercial value of porphyry copper and molybdenum, as well as massive sulfur, manganese, and bauxite, have been found.

  10. Radioactivity and associated radiation hazards in ceramic raw materials and end products.

    Science.gov (United States)

    Viruthagiri, G; Rajamannan, B; Suresh Jawahar, K

    2013-12-01

    Studies have been planned to obtain activity and associated radiation hazards in ceramic raw materials (quartz, feldspar, clay, zircon, kaolin, grog, alumina bauxite, baddeleyite, masse, dolomite and red mud) and end products (ceramic brick, glazed ceramic wall and floor tiles) as the activity concentrations of uranium, thorium and potassium vary from material to material. The primordial radionuclides in ceramic raw materials and end products are one of the sources of radiation hazard in dwellings made of these materials. By the determination of the activity level in these materials, the indoor radiological hazard to human health can be assessed. This is an important precautionary measure whenever the dose rate is found to be above the recommended limits. The aim of this work was to measure the activity concentration of (226)Ra, (232)Th and (40)K in ceramic raw materials and end products. The activity of these materials has been measured using a gamma-ray spectrometry, which contains an NaI(Tl) detector connected to multichannel analyser (MCA). Radium equivalent activity, alpha-gamma indices and radiation hazard indices associated with the natural radionuclides are calculated to assess the radiological aspects of the use of the ceramic end products as decorative or covering materials in construction sector. Results obtained were examined in the light of the relevant international legislation and guidance and compared with the results of similar studies reported in different countries. The results suggest that the use of ceramic end product samples examined in the construction of dwellings, workplace and industrial buildings is unlikely to give rise to any significant radiation exposure to the occupants.

  11. An active dealkalization of red mud with roasting and water leaching

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaobo, E-mail: zhuxiaobo0119@126.com [School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo, Henan 454000 (China); Henan Key Discipline Open Laboratory of Mining Engineering Materials, Henan 454000 (China); Li, Wang; Guan, Xuemao [School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo, Henan 454000 (China); Henan Key Discipline Open Laboratory of Mining Engineering Materials, Henan 454000 (China)

    2015-04-09

    Highlights: • The dealkalization of active roasting and water leaching from red mud was put forward. • The main factors on dealkalization during active roasting and water leaching were investigated. • The mechanism of dealkalization from red mud was in-depth studied in the process. - Abstract: The research has focused on the dealkalization of red mud after active roasting and water leaching, which is obtained from bauxite during alumina production. The main factors such as roasting temperature, roasting time, water leaching stage, leaching temperature, leaching reaction time and liquid to solid ratio were investigated. The mechanism of dealkalization was in-depth studied by using ICP–AES, XRD, TG-DSC, SEM–EDS and leaching kinetic. The results show that the dealkalization rate reached 82% under the condition of roasting temperature of 700 °C, roasting time of 30 min, four stage water leaching, liquid to solid ratio of 7 mL/g, leaching temperature of 90 °C and reaction time of 60 min. The diffraction peak of Na{sub 6}CaAl{sub 6}Si{sub 6}(CO{sub 3})O{sub 24}·2H{sub 2}O in red mud was decreased during the active roasting process, whereas the mineral phases of NaOH·H{sub 2}O and Na{sub 2}Ca(CO{sub 3}){sub 2} were appeared. The content of alkali obviously decreased and the grade of other elements increased during the process of active roasting and water leaching, which was in favor of next application process of red mud. The water leaching was controlled by internal diffusion of SCM and the apparent activation energy was 22.63 kJ/mol.

  12. Atmospheric mercury emissions in Australia from anthropogenic, natural and recycled sources

    Science.gov (United States)

    Nelson, Peter F.; Morrison, Anthony L.; Malfroy, Hugh J.; Cope, Martin; Lee, Sunhee; Hibberd, Mark L.; Meyer, C. P. (Mick); McGregor, John

    2012-12-01

    The United Nations Environment Programme (UNEP) has begun a process of developing a legally binding instrument to manage emissions of mercury from anthropogenic sources. The UNEP Governing Council has concluded that there is sufficient evidence of significant global adverse impacts from mercury to warrant further international action; and that national, regional and global actions should be initiated as soon as possible to identify populations at risk and to reduce human generated releases. This paper describes the development of, and presents results from, a comprehensive, spatially and temporally resolved inventory of atmospheric mercury emissions from the Australian landmass. Results indicate that the best estimate of total anthropogenic emissions of mercury to the atmosphere in 2006 was 15 ± 5 tonnes. Three industrial sectors contribute substantially to Australian anthropogenic emissions: gold smelting (˜50%, essentially from a single site/operation), coal combustion in power plants (˜15%) and alumina production from bauxite (˜12%). A diverse range of other sectors contribute smaller proportions of the emitted mercury, but industrial emissions account for around 90% of total anthropogenic mercury emissions. The other sectors include other industrial sources (mining, smelting, and cement production) and the use of products containing mercury. It is difficult to determine historical trends in mercury emissions given the large uncertainties in the data. Estimates for natural and re-emitted emissions from soil, water, vegetation and fires are made using meteorological models, satellite observations of land cover and soil and vegetation type, fuel loading, fire scars and emission factors which account for the effects of temperature, insolation and other environmental variables. These natural and re-emitted sources comfortably exceed the anthropogenic emissions, and comprise 4-12 tonnes per year from vegetation, 70-210 tonnes per year from soils, and 21-63 tonnes

  13. Preparation of Calcium Sulphoaluminate by Industrial Wastes and Analysis of Activation on Fly Ash in Concrete%工业废渣制备硫铝酸钙及对混凝土中粉煤灰的激发性能研究

    Institute of Scientific and Technical Information of China (English)

    叶强; 马兵; 马骥

    2012-01-01

    Instead of calcium sulphoaluminate by free Desulfurization Gypsum, bauxite by fly ash, it inuestigates the activation of fly ash in C25 ,C30 ,C40. It shows that calcium sulphoaluminate can be prepared in 1280℃ without soaking. Calcium sulphoaluminate can active the hydra-tion of fly ash effectively, in the early hydration period, ettringite can be formed quickly which contribute to the strength of 3d and 28d. In different grade concrete, compressive strength increase 19.7% ,23.2% ,54.9% respectively.%通过利用工业废渣脱硫石膏代替天然石膏,粉煤灰代替部分铝矾土制备硫铝酸钙矿物,同时研究了硫铝酸钙对不同标号(C25,C30,C40)混凝土中粉煤灰的激发性能.研究表明利用工业废渣在1280℃不需保温即可制备纯硫铝酸钙矿物.此外,研究表明硫铝酸钙在不同掺量粉煤灰的混凝土中可以促进粉煤灰的早期水化,同时生成钙钒石,有效的提高混凝土3d、28d的强度.对于C25,C30,C40级混凝土的28d强度分别提高了了19.7%,23.2%,54.9%.

  14. Research of Water-based Coating for LFC Steel Castings%消失模铸钢水基涂料研究

    Institute of Scientific and Technical Information of China (English)

    黄建波; 忽宝民

    2013-01-01

    选用铝矾土耐火熟料和铬矿粉作为复合耐火骨料,以酚醛树脂和硅溶胶作为复合粘结剂,钠基膨润土和粉状羧甲基纤维素钠(CMC)作为复合悬浮剂,通过正交试验确定消失模铸钢水基涂料的最佳配比,即钠基膨润土含量5%,粉状羧甲基纤维素钠0.5%,酚醛树脂2%,硅溶胶含量5%,并进行生产验证.结果表明,该涂料具有良好的工艺性能,解决了现有涂料在使用过程中存在的粘砂,气孔等问题,能够很好地满足实际生产需要,且成本低廉.%Selecting bauxite refractory aggregate and chromium slag as composite refractory aggregate,phenolic resin and silica sol as composite binder,and sodium bentonite and powdered sodium carboxymethyl cellulose (CMC) as composite suspension agent,the best ratio in EPC water-based paint was determined through the orthogonal test and production validation,that is sodium bentonite content 5%,CMC 0.5%,resin 2%,silica sol content 5%.The results show that,the coating has good processing performance,the problems of paint in the process of using sand,porosity and other issues were solved,which can better meet the needs of practical production,and the cost is low.

  15. Combined Application of QEM-SEM and Hard X-ray Microscopy to Determine Mineralogical Associations and Chemcial Speciation of Trace Metals

    Energy Technology Data Exchange (ETDEWEB)

    M Grafe; M Landers; R Tappero; P Austin; B Gan; A Grabsch; C Klauber

    2011-12-31

    We describe the application of quantitative evaluation of mineralogy by scanning electron microscopy in combination with techniques commonly available at hard X-ray microprobes to define the mineralogical environment of a bauxite residue core segment with the more specific aim of determining the speciation of trace metals (e.g., Ti, V, Cr, and Mn) within the mineral matrix. Successful trace metal speciation in heterogeneous matrices, such as those encountered in soils or mineral residues, relies on a combination of techniques including spectroscopy, microscopy, diffraction, and wet chemical and physical experiments. Of substantial interest is the ability to define the mineralogy of a sample to infer redox behavior, pH buffering, and mineral-water interfaces that are likely to interact with trace metals through adsorption, coprecipitation, dissolution, or electron transfer reactions. Quantitative evaluation of mineralogy by scanning electron microscopy coupled with micro-focused X-ray diffraction, micro-X-ray fluorescence, and micro-X-ray absorption near edge structure (mXANES) spectroscopy provided detailed insights into the composition of mineral assemblages and their effect on trace metal speciation during this investigation. In the sample investigated, titanium occurs as poorly ordered ilmenite, as rutile, and is substituted in iron oxides. Manganese's spatial correlation to Ti is closely linked to ilmenite, where it appears to substitute for Fe and Ti in the ilmenite structure based on its mXANES signature. Vanadium is associated with ilmenite and goethite but always assumes the +4 oxidation state, whereas chromium is predominantly in the +3 oxidation state and solely associated with iron oxides (goethite and hematite) and appears to substitute for Fe in the goethite structure.

  16. Research on Purification of Polyaluminum Chloride by Aluminum-carbon Micro-electrolysis Technology%铝碳微电解技术净化聚合氯化铝的研究

    Institute of Scientific and Technical Information of China (English)

    李荣寨

    2015-01-01

    The polyaluminum chloride produced by bauxite powder and by-product hydrochloric acid has many heavy metals and organic impurities. Referring to the principles of Fe-C micro-electrolysis, by artificially adding activated carbon and creating AL-C micro-electrolysis condition, the heavy metals and organic impurities of polyaluminum chloride can be removed. Under the condition of using the aluminum carbon ratio 1:1, the dynamic operation, the control parameters with the residence time at 1 hour, and the treatment costs about 6.67 yuan/ton, Pb2+content of polyaluminum chloride decreased from 23.3ppm to 5.8ppm, which is below the GB 10ppm requirements.%铝矿粉与副产盐酸生产的聚合氯化铝中重金属杂质和有机杂质往往较多,借鉴铁碳微电解原理,人为投加活性炭,创造铝碳微电解条件,用来去除聚合氯化铝中的重金属和有机杂质。在采用铝碳比1:1,动态操作,停留时间在1小时的控制参数,处理费用约6.67元/吨的条件下,原液铅Pb2+含量23.3ppm,处理后铅Pb2+含量下降到5.8ppm,低于国标10ppm的要求。

  17. Study on preparation of red mud & fly ash aerated concrete%赤泥-粉煤灰加气混凝土制备研究

    Institute of Scientific and Technical Information of China (English)

    王瑞燕; 岳涛

    2011-01-01

    赤泥是铝土矿提取氧化铝过程中产生的废弃物.赤泥建材化利用具有使用量大、产品附加值高等特点,是赤泥无害化、资源化利用的优选途径.以强度级别A3.5、密度级别B06的加气混凝土为设计目标,研究了组成材料、养护制度对赤泥-粉煤灰加气混凝土强度、密度的影响.结果表明,采用赤泥、粉煤灰等固体工业废料制备的加气混凝土,强度和密度满足加气混凝土砌块质量要求,满足建筑材料放射性核素限量要求.%Red mud is the waste generated in process of extracting alumina from bauxite. The utilization of red mud in preparing construction materials has features of large using amount and high added value,which is an optimal method for recycle and safe treatment of the red mud. To the target of aerated concrete with A3.5 strength grade and B06 density grade,influence of materials composition and curing conditions on strength and density of red mud & fly ash aerated concrete has been studied. Results show that for aerated concrete prepared with red mud,fly ash and other industrial solid waste,its strength and density can meet the quality requirements of aerated concrete block,and meet the radioactive species limit requirement of building material.

  18. Ecotoxicity of fluvial sediments downstream of the Ajka red mud spill, Hungary.

    Science.gov (United States)

    Klebercz, Orsolya; Mayes, William M; Ánton, Aron Dániel; Feigl, Viktória; Jarvis, Adam P; Gruiz, Katalin

    2012-08-01

    An integrated assessment of biological activity and ecotoxicity of fluvial sediments in the Marcal river catchment (3078 km(2)), western Hungary, is presented following the accidental spill of bauxite processing residue (red mud) in Ajka. Red mud contaminated sediments are characterised by elevated pH, elevated trace element concentrations (e.g. As, Co, Cr, V), high exchangeable Na, and induce an adverse effect on test species across a range of trophic levels. While background contamination of the river system is highlighted by adverse effects on some test species at sites unaffected by red mud, the most pronounced toxic effects apparent in Vibrio fischeri bioluminescence inhibition, Lemna minor bioassay and Sinapis alba root and shoot growth occur at red mud depositional hotspots in the lower Torna Creek and upper Marcal. Heterocypris incongruens bioassays show no clear patterns, although the most red mud-rich sites do exert an adverse effect. Red mud does however appear to induce an increase in the density of aerobic and facultative anaerobic bacterial communities when compared with unaffected sediments and reference sites. Given the volume of material released in the spill, it is encouraging that the signal of the red mud on aquatic biota is visible at a relatively small number of sites. Gypsum-affected samples appear to induce an adverse effect in some bioassays (Sinapis alba and Heterocypris incongruens), which may be a feature of fine grain size, limited nutrient supply and greater availability of trace contaminants in the channel reaches that are subject to intense gypsum dosing. Implications for monitoring and management of the spill are discussed.

  19. Environmental impact of toxic elements in red mud studied by fractionation and speciation procedures.

    Science.gov (United States)

    Milačič, Radmila; Zuliani, Tea; Ščančar, Janez

    2012-06-01

    Aluminum (Al) is mostly produced from bauxite ore, which contains up to 70% of Al(2)O(3) (alumina). Before alumina is refined to aluminum metal, it is purified by hot alkaline extraction. As a waste by-product red mud is formed. Due to its high alkalinity and large quantities, it represents a severe disposal problem. In Kidričevo (Slovenia), red mud was washed with water before disposal, and after drying, covered with soil. In Ajka (Hungary), the red mud slurry was collected directly in a containment structure, which burst caused a major accident in October 2010. In the present work the environmental impact of toxic elements in red mud from Kidričevo and Ajka were evaluated by applying a sequential extraction procedure and speciation analysis. The predominant red mud fraction was the insoluble residue; nevertheless, environmental concern was focused on the highly mobile water-soluble fraction of Al and Cr. Al in the water-soluble Ajka mud fraction was present exclusively in form of toxic [Al(OH)(4)](-), while Cr existed in its toxic hexavalent form. Comparative assessment to red mud from Kidričevo (Slovenia) with a lower alkalinity (pH 9) with that from Ajka demonstrated significantly lower Al solubility and the presence of only trace amounts of Cr(VI), confirming that disposal of neutralized mud is environmentally much more acceptable and carries a smaller risk of ecological accidents. Since during the Ajka accident huge amounts of biologically available Al and moderate Cr(VI) concentrations were released into the terrestrial and aquatic environments, monitoring of Al and Cr(VI) set free during remedial actions at the contaminated site is essential. Particular care should be taken to minimize the risk of release of soluble Al species and Cr(VI) into water supplies and surface waters.

  20. Neutralization of red mud with pickling waste liquor using Taguchi's design of experimental methodology.

    Science.gov (United States)

    Rai, Suchita; Wasewar, Kailas L; Lataye, Dilip H; Mishra, Rajshekhar S; Puttewar, Suresh P; Chaddha, Mukesh J; Mahindiran, P; Mukhopadhyay, Jyoti

    2012-09-01

    'Red mud' or 'bauxite residue', a waste generated from alumina refinery is highly alkaline in nature with a pH of 10.5-12.5. Red mud poses serious environmental problems such as alkali seepage in ground water and alkaline dust generation. One of the options to make red mud less hazardous and environmentally benign is its neutralization with acid or an acidic waste. Hence, in the present study, neutralization of alkaline red mud was carried out using a highly acidic waste (pickling waste liquor). Pickling waste liquor is a mixture of strong acids used for descaling or cleaning the surfaces in steel making industry. The aim of the study was to look into the feasibility of neutralization process of the two wastes using Taguchi's design of experimental methodology. This would make both the wastes less hazardous and safe for disposal. The effect of slurry solids, volume of pickling liquor, stirring time and temperature on the neutralization process were investigated. The analysis of variance (ANOVA) shows that the volume of the pickling liquor is the most significant parameter followed by quantity of red mud with 69.18% and 18.48% contribution each respectively. Under the optimized parameters, pH value of 7 can be achieved by mixing the two wastes. About 25-30% of the total soda from the red mud is being neutralized and alkalinity is getting reduced by 80-85%. Mineralogy and morphology of the neutralized red mud have also been studied. The data presented will be useful in view of environmental concern of red mud disposal.

  1. Immobilization of 60Co and 90Sr ions using red mud from aluminum industry

    Directory of Open Access Journals (Sweden)

    Milenković Aleksandra S.

    2014-01-01

    Full Text Available The removal of 60Co and 90Sr from the aqueous phase was tested using red mud - the fine grained residue from bauxite ore processing. This industrial waste represents a mixture of numerous minerals, mainly oxides and hydroxides of Fe, Al, Si, and Ti. Experiments were conducted as a function of contact time, pH, and pollutant concentrations. Kinetic data were well fitted with a pseudo-second order equation. The calculated rate constants and initial sorption rates indicated faster sorption of Sr2+ ions. Removal of both cations rapidly increased with the initial pH increase from 2.5 to 3.5. With the further increase of pH, Co2+ sorption was nearly constant (98%-100%, whereas Sr2+ removal remained at the same level to initial pH ~8 and gradually increased to 100% at pH 12. Equilibrium sorption data followed the Langmuir model, with the maximum sorption capacities of 0.52 mmol/g for Co2+ and 0.31 mmol/g for Sr2+. Sorbed cations exhibited high stability in distilled water. Desorption of Co2+ was also negligible in the presence of the competing Ca2+ cation, while 42%-25% of Sr2+ ions were desorbed depending on the previously sorbed amount. The results indicate that red mud is of potential significance as Co2+ and Sr2+ immobilization agent due to its high efficiency, abundance, and low-cost. [Projekat Ministarstva nauke Republike Srbije, br. 43009

  2. Reply to the comment of Mitchell et al. on "Geomorpho-tectonic evolution of the Jamaican restraining bend" by L. Domínguez-González, L. Andreani, K.P. Stanek and R. Gloaguen [Geomorphology, 228 (2015) 320-334

    Science.gov (United States)

    Domínguez-González, Leomaris; Andreani, Louis; Stanek, Klaus P.; Gloaguen, Richard

    2016-06-01

    We reply to the comments of Mitchell et al. on our paper entitled "Geomorpho-tectonic evolution of the Jamaican restraining bend". The comments contain statements about the methods that need to be balanced. We agree that the interpretation of the modeled drainage network in some karstified parts of the Jamaican island is difficult, but this does not affect the validity of our analysis elsewhere. We consider that our geomorphic analyses (which also include topographic profiles and morphometric maps) are still valid. The view expressed by Mitchell et al. that we used serially developed landscapes to 'date' progressive uplift is an oversimplification of our discussion. We highlighted the differences between the geomorpho-tectonic provinces of Jamaica, and we proposed to explain these differences by a model which involves (1) a westward propagation of the restraining bend and (2) a difference in tectonic styles between the different provinces of Jamaica. Our interpretation does not contradict existing models based on seismotectonic data, provenance analysis or on the origin of Jamaican bauxite. There is a disagreement between James-Williamson et al. (2014), which suggested that central Jamaica was already being uplifted by the end of the Late Miocene, and Domínguez-González et al. (2015), which proposed a Pliocene to present onset of the NE-trending compression toward the SW. However, the timing of the deformation in central and western Jamaica is still poorly constrained and, at this time, any interpretation of the uplift history of central Jamaica should be considered as hypothetical.

  3. Geochemical evidence for African dust and volcanic ash inputs to terra rossa soils on carbonate reef terraces, northern Jamaica, West Indies

    Science.gov (United States)

    Muhs, D.R.; Budahn, J.R.

    2009-01-01

    The origin of red or reddish-brown, clay-rich, "terra rossa" soils on limestone has been debated for decades. A traditional qualitative explanation for their formation has been the accumulation of insoluble residues as the limestone is progressively dissolved over time. However, this mode of formation often requires unrealistic or impossible amounts of carbonate dissolution. Therefore, where this mechanism is not viable and where local fluvial or colluvial inputs can be ruled out, an external source or sources must be involved in soil formation. On the north coast of the Caribbean island of Jamaica, we studied a sequence of terra rossa soils developed on emergent limestones thought to be of Quaternary age. The soils become progressively thicker, redder, more Fe- and Al-rich and Si-poor with elevation. Furthermore, although kaolinite is found in all the soils, the highest and oldest soils also contain boehmite. Major and trace element geochemistry shows that the host limestones and local igneous rocks are not likely source materials for the soils. Other trace elements, including the rare earth elements (REE), show that tephra from Central American volcanoes is not a likely source either. However, trace element geochemistry shows that airborne dust from Africa plus tephra from the Lesser Antilles island arc are possible source materials for the clay-rich soils. A third, as yet unidentified, source may also contribute to the soils. We hypothesize that older, more chemically mature Jamaican bauxites may have had a similar origin. The results add to the growing body of evidence of the importance of multiple parent materials, including far-traveled dust, to soil genesis.

  4. Silica sand for oil and gas production : a technical market overview

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, J.C. [BJ Services Company, Calgary, AB (Canada)

    2006-07-01

    In order to meet the growing demand for oil, petroleum production companies have initiated aggressive globally oriented drilling programs. In Canada and the United States, the average monthly rig count has doubled from 1103 rigs in 1990 to 2213 in 2006, with 53 per cent of the growth taking place in the last 3 years. Extensive damage occurs in the hydrocarbon rich formations during the drilling process of new wells. In order to stimulate and reconnect the well to the reservoir, completion processes such as hydraulic fracturing, are needed. In hydraulic fracturing, a viscous fluid is injected into the well at a rate and pressure sufficient to initiate a crack behind the casing perforations. When the fracture attains adequate width and length, silica sand or other proppants are added to the fluid to fill the created fracture. These may include Ottawa Sand, Brady Sand, bauxite, intermediate strength ceramics or resin coated sands. The use of proppants prevents the fracture from healing and provides a super conductive drainage channel for hydrocarbons. The proppant should provide the highest porosity to maximize permeability of the proppant pack. Hydrocarbon production can therefore be increased at relatively low costs. This paper reviewed the stringent industry specifications that various grades of proppant must meet, as defined by the American Petroleum Institute. The technical aspects of proppant testing were outlined with reference to proppant size, sphericity, acid solubility, turbidity, crush resistance, and testing for ceramic proppants. Despite improved logging and advances in well stimulation treatments, market trends indicate that hydraulic fracturing and proppants will continue to be an important aspect of oil and gas production. 22 refs., 3 tabs., 5 figs.

  5. Long-term Sustainability of Fracture Conductivity in Geothermal Systems using Proppants

    Energy Technology Data Exchange (ETDEWEB)

    Earl D Mattson; Ghanashyam Neupane; Mitchell Plummer; Clay Jones; Joe Moore

    2016-02-01

    Long-term sustainability of fracture conductivity is critical for commercial success of engineered geothermal system (EGS) and hydrogeothermal field sites. The injection of proppants has been suggested as a means to enhance the conductivity in these systems. Several studies have examined the chemical behavior of proppants that are not at chemical equilibrium with the reservoir rock and water. These studies have suggested that in geothermal systems, geochemical reactions can lead to enhance proppant dissolution and deposition alteration minerals. We hypothesize that proppant dissolution will decrease the strength of the proppant and can potentially reduce the conductivity of the fracture. To examine the geomechanical strength of proppants, we have performed modified crushing tests of proppants and reservoir rock material that was subjected to geothermal reservoir temperature conditions. The batch reactor experiments heated crushed quartz monzonite rock material, proppants (either quartz sand, sintered bauxite or kryptospheres) with Raft River geothermal water to 250 ºC for a period of 2 months. Solid and liquid samples were shipped to University of Utah for chemical characterization with ICP-OES, ICP-MS, and SEM. A separate portion of the rock/proppant material was subjected to a modified American Petroleum Institute ISO 13503-2 proppant crushing test. This test is typically used to determine the maximum stress level that can be applied to a proppant pack without the occurrence of unacceptable proppant crushing. We will use the test results to examine potential changes in proppant/reservoir rock geomechanical properties as compared to samples that have not been subjected to geothermal conditions. These preliminary results will be used to screen the proppants for long term use in EGS and hot hydrogeothermal systems.

  6. An in situ FTIR-ATR study of polyacrylate adsorbed onto hematite at high pH and high ionic strength.

    Science.gov (United States)

    Kirwan, Luke J; Fawell, Phillip D; van Bronswijk, Wilhelm

    2004-05-11

    FTIR-ATR was used to examine in situ the interaction of polyacrylate and hematite at pH 13. Static light scattering and mobility measurements were used to assess solution polyacrylate dimensions and hematite surface charge, respectively. Polyacrylate adsorption occurred only with the addition of electrolyte (e.g., NaCl), and it was found that excess cations, up to approximately 1 M, facilitated adsorption, above which the effect was found to plateau. At pH 13 and at low ionic strength, adsorption of polyacrylate onto hematite is facilitated by cations in solution shielding both the negative acrylate functionality of the polymer and the negative hematite surface. The shielding of the hematite surface continues to increase with increasing salt concentration up to a measured 3 M. Similarly, the shielding of the polymer increased with electrolyte concentration up to approximately 1 M salt, beyond which no further increase in shielding was observed. At this concentration the polymer assumes a finite minimum size in solution that ultimately limits the amount adsorbed. The dimension of the polymer in solution was found to be independent of monovalent cation type. Thus, at high pH and high ionic strength adsorption is determined by the degree of hematite surface charge reduction. The cation-hematite surface interaction was found to be specific, with lithium leading to greater polyacrylate adsorption than sodium, which was followed by cesium. The stronger affinity of lithium for the hematite surface over sodium and cesium is indicative of the inverse lyotropic adsorption series and has been rationalized in the past by the "structure-making-structure-breaking" model. These results provide a useful insight into the likely adsorption mechanism for polyacrylate flocculants at high pH and ionic strength onto residues in the Bayer processing of bauxite.

  7. Global stocks of selected mineral-based commodities

    Science.gov (United States)

    Wilburn, David R.; Bleiwas, Donald I.; Karl, Nick A.

    2016-12-05

    IntroductionThe U.S. Geological Survey, National Minerals Information Center, analyzes mineral and metal supply chains by identifying and describing major components of mineral and material flows from ore extraction, through intermediate forms, to a final product. This report focuses on an important component of the world’s supply chain: the amounts and global distribution of major consumer, producer, and exchange stocks of selected mineral commodities. In this report, the term “stock” is used instead of “inventory” and refers to accumulations of mined ore, intermediate products, and refined mineral-based commodities that are in a form that meets the agreed-upon specifications of a buyer or processor of intermediate products. These may include certain ores such as bauxite, concentrates, smelter products, and refined metals. Materials sometimes referred to as inventory for accounting purposes, such as ore contained in a deposit or in a leach pile, or materials that need to be further processed before they can be shipped to a consumer, are not considered. Stocks may be held (owned) by consumers, governments, investors, producers, and traders. They may serve as (1) a means to achieve economic, social, and strategic goals through government policies; (2) a secure source of supply to meet demand and to mitigate potential shortages in the supply chain; (3) a hedge to mitigate price volatility; and (4) vehicles for speculative investment.The paucity and uneven reliability of data for stocks of ores and concentrates and for material held by producers, consumers, and merchants hinder the accurate estimating of the size and distribution of this portion of the supply chain for certain commodities. This paper reviews the more visible stocks held in commodity exchange warehouses distributed throughout the world.

  8. Granular-bed Filtration Assisted by Filter Cake Formation: Advanced Design and Experimental Verification

    Energy Technology Data Exchange (ETDEWEB)

    Gaarder, Kavitha Pathmanathan

    2011-07-01

    Particulate matter removal at high temperatures has gained a great attention in the last years due to the vast growing of power production plants around the world. A reliable and robust gas cleaning method is inherently necessary to facilitate efficient fuel to energy conversion while protecting all the downstream equipment s in a plant. In accordance with the current demand, a detail study has been conducted on panel bed filter which exhibits the suitable characteristic for high temperature applications.The thesis focuses on four main parts related to the design evaluation, experimental verification and development of new apparatus and method for regeneration in a panel bed filter. The four main parts are as following;1. Testing of an advanced new louver design, filter tray, at room and elevated temperature 2. Development of a new apparatus and method for puff-back cleaning 3. Testing of filter tray with the new puff-back apparatus and 4. Industrial scale panel bed filter testing in a commercial combustion plant. A very first laboratory scale panel bed filter with filter tray louvers was built and tested at room temperature. Tests were performed mainly at higher filtration velocities (7 - 31cm/s) with sintered bauxite spherical particles (mean diameter of 710 m) as filtration medium with standardized test dust (mean diameter of 9 m). The filter demonstrated excellent results at filtration velocity of 30 cm/s however unstable residual pressure drop profile and high dust penetration were recorded, suggesting the depth of the granular beds are too shallow. A second laboratory scale panel-bed filter with filter tray louvers with deeper granular beds, i.e. 40 mm was built. The gas-entry surfaces are much larger than the first test rig. Tests were performed from low to high filtration velocities with sintered bauxite spherical particles (mean diameter of 470 and 710 m) and olivine sand particles (mean diameter of 545 m) as filtration medium and standardized test dust

  9. Cameroon.

    Science.gov (United States)

    1992-06-01

    The US profile of Cameroon indicates brief statistics on the population, geography, government, and economy and brief descriptions of the population, the history, government, political conditions, the economy, foreign relations, defense, and relations with the US. Principal government and US officials are furnished. The 1991 estimated population of Cameroon was 11.7 million of which 60% is rural. There are 200 different tribes who speak many African languages and dialects. The French and English languages both have official status. Muslims live in the north and Christians in the south. 80% live in the formerly French east. The growth rate is 3%. There is 65% literacy. Infant mortality is 20%. 70% are agricultural workers, 13% industrial and commercial, and 17% other. The government is an independent republic with an executive and legislative branch. Independence was achieved in 1960. There is 1 ruling party. Traditional courts administer the laws. Traditional rulers are treated as administrative adjuncts. Suffrage is universal adult. The central government budget is 1.4 billion of which 8.7% is for defense. There are 10 provinces and 4 major cities. The seaport city Douala is the largest at 1.5 million. Gross domestic product (GDP) is $12.5 billion with an annual growth rate of 4.3% and an inflation rate of 2%. Growth has been variable since 1988 and reached a low of 2.4% in 1988-89. Oil, natural gas, bauxite, iron core, and timber are natural resources. 27% of the GDP is in agricultural products (cocoa, coffee, cotton, fishing, and forestry). 13% of the GDP is manufacturing and 24% is industry. Exports are valued at $2.9 billion and imports at $2.2 billion. Major markets are France, Netherlands, and the US. Imports include intermediate goods, capital goods, fuel and lubricants, foodstuffs, beverages, and tobacco. Early inhabitants were the Pygmies, followed later by Bantu speakers, and Muslim Fulani. Political consolidation was achieved in 1970 after a period of

  10. Synthesis and Performance Investigation of Mullite Materials by Recycling Waste Fly Ash%粉煤灰资源化合成莫来石材料及其性能研究

    Institute of Scientific and Technical Information of China (English)

    谭丽; 董应超; 孙丽

    2011-01-01

    以天然铝矾土和工业废物粉煤灰为原料,运用反应烧结合成了低成本的莫来石陶瓷材料.结果证明,刚玉与方石英相在1200~1300℃间通过固态反应生成二次莫来石,在温度高于1300℃时,刚玉相熔于短暂玻璃相中.二次莫来石化及莫来石晶体生长所导致的样品体膨胀大于液相烧结所引起的收缩,导致样品出现膨胀现象.1600℃烧结样品的平均热膨胀系数为5.40×10-6℃-1,平均抗弯强度186.19 MPa.莫来石在强酸强碱热溶液中表现出两个阶段:快速阶段(0~5h)和低速阶段(5~20h),这分别对应于样品的表面腐蚀和体腐蚀过程.%Low-cost mullite ceramics were synthesized by reaction-sintering with natural bauxite and industrial waste fly ash as starting materials. The results indicate that secondary mullite was produced at 1200~1300℃ by the solid state reaction of cristobalite and corundum, followed by the dissolution of corundum into transitory glassy phase at higher temperatures (≥ 1300℃). The formation of secondary mullite and its growth resulted in a volume expansion, which was higher than the shrinkage induced by liquid-phase sintering. The samples sintered at 1600℃ had average thermal expansion coefficient of 5.40×10℃-1 and average bending strength of 186.19 Mpa. The sintered mullite exhibited two corrosion stages in hot strong acidic and alkaline solutions: fast stage (0~5h) and low-rate stage (5~20h), which respectively corresponded to the surface corrosion and bulk corrosion processes of the samples.

  11. Estudio comparativo del comportamiento electroquímico del hierro en medio alcalino en presencia de lodos rojos y lodos grises. Efecto del Al3+

    Directory of Open Access Journals (Sweden)

    Abreu, C. M.

    2009-02-01

    Full Text Available Red mud (RM is the main by-product of the Bayer process for alumina extraction from bauxite, and grey slurries (GS are generated during the granite rocks transformation processes. The huge volume of those wastes generated every year suppose a serious environmental problem. Recent works by our group demonstrate the efficiency of both types of muds as corrosion inhibitors for iron and steel in alkaline media containing chlorides. The elemental analysis of these slurries shows that Al3+ is the main common element. Therefore, the aim of this paper is to study the effect of the soluble Al3+ in the electrochemical behaviour of iron in alkaline media, in presence and absence of chlorides. The electrochemical study using Cyclic Voltammetry (CV and Electrochemical Impedance Spectroscopy (EIS together with surface analysis techniques allowed to conclude that Al3+ blocks the surface of steel in alkaline media chloride increasing the steel resistance to chloride attack.

    Los elevados volúmenes de residuos generados por los lodos rojos (LR, procedentes del proceso de obtención de la alúmina a partir de la bauxita y los lodos grises (LG, originados durante el proceso de la transformación del granito, suponen un grave problema medioambiental. Trabajos recientes de este grupo demuestran la eficacia de ambos tipos de lodos como inhibidores de la corrosión del hierro y acero en medio alcalino clorurado. Esta característica ha llevado al estudio individualizado de sus componentes mayoritarios y, dentro de éstos, el Al3+, elemento común presente en mayor proporción. El estudio mediante técnicas electroquímicas como la Voltametría Cíclica (VC y la Espectroscopía de Impedancia Electroquímica (EIE, apoyadas en técnicas de análisis químico y superficial, ha permitido visualizar cómo el Al3+ es capaz de bloquear la superficie del acero en medio alcalino aumentando su resistencia al ataque

  12. Influence of ferrite phase in alite-calcium sulfoaluminate cements

    Science.gov (United States)

    Duvallet, Tristana Yvonne Francoise

    Since the energy crisis in 1970's, research on low energy cements with low CO2- emissions has been increasing. Numerous solutions have been investigated, and the goal of this original research is to create a viable hybrid cement with the components of both Ordinary Portland cement (OPC) and calcium sulfoaluminate cement (CSAC), by forming a material that contains both alite and calcium sulfoaluminate clinker phases. Furthermore, this research focuses on keeping the cost of this material reasonable by reducing aluminum requirements through its substitution with iron. The aim of this work would produce a cement that can use large amounts of red mud, which is a plentiful waste material, in place of bauxite known as an expensive raw material. Modified Bogue equations were established and tested to formulate this novel cement with different amounts of ferrite, from 5% to 45% by weight. This was followed by the production of cement from reagent chemicals, and from industrial by-products as feedstocks (fly ash, red mud and slag). Hydration processes, as well as the mechanical properties, of these clinker compositions were studied, along with the addition of gypsum and the impact of a ferric iron complexing additive triisopropanolamine (TIPA). To summarize this research, the influence of the addition of 5-45% by weight of ferrite phase, was examined with the goal of introducing as much red mud as possible in the process without negatively attenuate the cement properties. Based on this PhD dissertation, the production of high-iron alite-calcium sulfoaluminateferrite cements was proven possible from the two sources of raw materials. The hydration processes and the mechanical properties seemed negatively affected by the addition of ferrite, as this phase was not hydrated entirely, even after 6 months of curing. The usage of TIPA counteracted this decline in strength by improving the ferrite hydration and increasing the optimum amount of gypsum required in each composition

  13. Recycling of used Al2O3-SiC-C bricks%用后Al2O3-SiC-C砖的回收再利用

    Institute of Scientific and Technical Information of China (English)

    王落霞; 沈明科; 高斌

    2011-01-01

    对铁水包和混铁车用后的Al2O3-SiC-C(简称ASC)砖进行再生处理,然后以高铝矾土熟料、电熔刚玉、叶蜡石、SiC粉和鳞片石墨为原料,分别掺加质量分数为10%、20%、30%的Al2O3-SiC-C再生料制备了铁水包用和混铁车用再生Al2O3-SiC-C砖.与原砖相比,再生砖的体积密度和常温耐压强度较高,显气孔率较低,而高温抗折强度、抗氧化性、抗渣性与原砖的差距不大.过多添加ASC再生料对再生Al2O3-SiC-C砖的高温抗折强度和抗渣侵蚀性能不利,以统料形式添加时,混铁车用Al2O3-SiC-C衬砖中ASC再生料的添加量(w)不宜超过30%.%Recycled AI2O3-SiC-C bricks for iron ladle and torpedo ladle were prepared using high alumina bauxite clinker,fused corundum,pyrauxite,SiC powder and flake graphite as starting materials,adding 10%,20% and 30% (mass percent) of recycled materials made from used AI2O3-SiC-C bricks,respectively. Compared with the original bricks,the recycled bricks have high bulk density and cold crushing strength,low apparent porosity,but similar hot modulus of rupture,oxidation resistance and slag corrosion resistance. The excessive recycled AI2O3-SiC-C material is harmful to hot modulus of rupture and slag corrosion resistance of the recycled bricks,and its proper addition in working lining bricks of torpedo ladle should not exceed 30%.

  14. Optimization of Mineral Composition of High Belite-sulphoaluminate Clinker%高贝利特硫铝酸盐熟料矿物组成优化

    Institute of Scientific and Technical Information of China (English)

    李娟; 周春英; 杨亚晋

    2012-01-01

    The belite-calcium sulphoaluminate cement (BCSA) clinker with belite(C2S) of 35%-65%, calcium sulphoaluminate (C4A3S) of 20%-50%, and ferrite (CaAF) of 5%-15% was prepared with four major raw materials like limestone, bauxite, clay and gypsum. Two aspects on the preparation of BCSA clinker are (1) burnability of raw meal and (2) optimization of clinker phasesand gypsum content in cement. The results show that the cement with clinker burned during 1 280-1 320 ℃ containing C4A3S of 32%-42%, C4AF of 5%-9%, C2S of 46%-56% and gypsum of 12.5% can give the average mechanical strength of 55 MPa at 28 days. Compared to OPC, the BCSA cement consumes less energy and emits less emission.%采用石灰石、矾土、黏土和石膏 4 种原料,制备了以贝利特、无水硫铝酸钙和铁相为主的高贝利特无水硫铝酸盐水泥(BCSA)熟料矿物体系,研究了其生料易烧性、熟料煅烧制度和熟料矿物优化配比等。结果表明:当 BCSA 熟料煅烧温度为 1280~1320 ℃时,可获得结晶度良好、形成数量较多的贝利特和无水硫铝酸钙矿物。在 BCSA 熟料矿物组成为 32%~42% C4A3S—、5%~9% C4AF、46%~56% C2S,石膏掺量为 12.5%时,水泥 28 d抗压强度达最佳,为 55MPa。此外,由于熟料烧成温度及氧化钙总含量(约 50%)均较低,BCSA 水泥在能耗和排放方面均比普通硅酸盐水泥低。

  15. Rare earth minerals and resources in the world

    Energy Technology Data Exchange (ETDEWEB)

    Kanazawa, Yasuo [Human Resource Department, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba 305-8568 (Japan)]. E-mail: y.kanazawa@aist.go.jp; Kamitani, Masaharu [Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8567 (Japan)

    2006-02-09

    About 200 rare earth (RE) minerals are distributed in a wide variety of mineral classes, such as halides, carbonates, oxides, phosphates, silicates, etc. Due to the large ionic radii and trivalent oxidation state, RE ions in the minerals have large coordination numbers (c.n.) 6-10 by anions (O, F, OH). Light rare earth elements (LREEs) tend to occupy the larger sites of 8-10 c.n. and concentrate in carbonates and phosphates. On the other hand, heavy rare earth elements (HREEs) and Y occupy 6-8 c.n. sites and are abundant in oxides and a part of phosphates. Only a few mineral species, such as bastnaesite (Ce,La)(CO{sub 3})F, monazite (Ce,La)PO{sub 4}, xenotime YPO{sub 4}, and RE-bearing clay have been recovered for commercial production. Bayan Obo, China is the biggest RE deposit in the world. One of probable hypotheses for ore geneses is that the deposit might be formed by hydrothermal replacement of carbonate rocks of sedimentary origin. The hydrothermal fluid may be derived from an alkaline-carbonatite intrusive series. Following Bayan Obo, more than 550 carbonatite/alkaline complex rocks constitute the majority of the world RE resources. The distribution is restricted to interior and marginal regions of continents, especially Precambrian cratons and shields, or related to large-scale rift structures. Main concentrated areas of the complexes are East African rift zones, northern Scandinavia-Kola peninsula, eastern Canada and southern Brazil. Representative sedimentary deposits of REE are placer- and conglomerate-types. The major potential countries are Australia, India, Brazil, and Malaysia. Weathered residual deposits have been formed under tropical and sub-tropical climates. Bauxite and laterite nickel deposit are the representative. Ion adsorption clay without radioactive elements is known in southern China. Weathering processes concentrate REE in a particular clay mineral-layer in the weathered crusts whose source were originally REE-rich rocks like granite

  16. Geogenic fluoride and arsenic contamination in the groundwater environments in Tanzania

    Science.gov (United States)

    Bhattacharya, Prosun; Lesafi, Fina; Filemon, Regina; Ligate, Fanuel; Ijumulana, Julian; Mtalo, Felix

    2016-04-01

    materials such as pumice, bauxite, ferralsols and bone char. Developing innovative technologies, pilot-scale implementation and scaling-up water purification based on the locally available adsorbents is thus necessary to safeguard the public health for communities exposed to high levels of fluoride and arsenic in drinking water.

  17. Toxic element mobility assessment and modeling for regional geo-scientific survey to support Risk Assessment in a European Union context

    Science.gov (United States)

    Abdaal, Ahmed; Jordan, Gyozo; Bartha, Andras; Fugedi, Ubul

    2013-04-01

    The Mine Waste Directive 2006/21/EC requires the risk-based inventory of all mine waste sites in Europe. The geochemical documentation concerning inert classification and ranking of the mine wastes requires detailed field study and laboratory testing and analyses of waste material to assess the Acid Mine Drainage potential and toxic element mobility. The procedure applied in this study used a multi-level decision support scheme including: 1) expert judgment, 2) data review, 3) representative field sampling and laboratory analysis of formations listed in the Inert Mining Waste List, and 4) requesting available laboratory analysis data from selected operating mines. Based on expert judgment, the listed formations were classified into three categories. A: inert B: probably inert, but has to be checked, C: probably not inert, has to be examined. This paper discusses the heavy metal contamination risk assessment (RA) in leached quarry-mine waste sites in Hungary. In total 34 mine waste sites (including tailing lagoons and heaps of both abandoned mines and active quarries) have been selected for scientific testing using the EU Pre-selection Protocol. Over 93 field samples have been collected from the mine sites including Ore (Andesite and Ryolite), Coal (Lignite, black and brown coals), Peat, Alginite, Bauxite, Clay and Limestone. Laboratory analyses of the total toxic element content (aqua regia extraction), the mobile toxic element content (deionized water leaching) and the analysis of different forms of sulfur (sulfuric acid potential) ) on the base of Hungarian GKM Decree No. 14/2008. (IV. 3) concerning mining waste management. A detailed geochemical study together with spatial analysis and GIS has been performed to derive a geochemically sound contamination RA of the mine waste sites. Key parameters such as heavy metal and sulphur content, in addition to the distance to the nearest surface and ground water bodies, or to sensitive receptors such as settlements and

  18. Geochemical study of urban soils in public areas of an industrialized town (Ajka, western Hungary)

    Science.gov (United States)

    Zacháry, D.; Jordán, Gy.; Szabó, Cs.

    2012-04-01

    Soil is one of the most essential parts of urban ecosystem contributing to the biogeochemical cycles along the rock-soil-plant-animal and human pathway. Soil plays a fundamental role in plant nutrient uptake and groundwater filtration, too. Urban soils differ from non-urban soils in many aspects, including their origin, and they may also concentrate contaminants in large quantities due to intensive human activities. The pollution sources are industry, traffic, fertilizer, tailing and waste. In addition to the increasing rate of urban areas, urban soils are under growing interest and their pollution have received significant attention in the past few decades. This work focuses on the toxic element (As, Hg, Pb, Cu, Zn, Cd, Ni) content of soils and their spatial distribution in order to find a link between contamination sources and the receiving urban soils at sensitive receptor locations such as children's playgrounds and parks. Ajka town is located in western Hungary. It has an old-established industrial history with multiple contamination sources of heavy alumina industry and coal-based power plants supplied by the nearby bauxite and coal mines. At 44 locations 46 soil samples have been collected at a depth of 0-10 cm along a 1x1 km grid. The whole grid covers an area of 48 km2. In each grid cell a sampling site was selected at public areas. Sample preparation included drying at 40 C°, thorough homogenization and sieving to 2 mm fine earth before chemical analysis. Grain size distribution and soil pH were also determined. Samples were analyzed with ICP-OES and SEM methods. The As, Hg, Pb, Cu, Zn, Cd and Ni concentrations range from 2.07 ppm to 9.48 ppm, 0.02 ppm to 2.84 ppm, 5.08 ppm to 35.74 ppm, 2.55 ppm to 47.78 ppm, 17.00 ppm to 91.00 ppm, 0.07 ppm to 0.61 ppm and 5.57 ppm to 32.09 ppm, respectively. The results revealed the contaminated areas associated with past industrial sites. This study also identified locations with considerable contamination at

  19. Evolution of the Paleogene succession of the western Himalayan foreland basin

    Directory of Open Access Journals (Sweden)

    B.P. Singh

    2013-03-01

    Full Text Available The Paleogene succession of the Himalayan foreland basin is immensely important as it preserves evidence of India-Asia collision and related records of the Himalayan orogenesis. In this paper, the depositional regime of the Paleogene succession of the Himalayan foreland basin and variations in composition of the hinterland at different stages of the basin developments are presented. The Paleogene succession of the western Himalayan foreland basin developed in two stages, i.e. syn-collisional stage and post-collisional stage. At the onset, chert breccia containing fragments derived from the hanging walls of faults and reworked bauxite developed as a result of erosion of the forebulge. The overlying early Eocene succession possibly deposited in a coastal system, where carbonates represent barriers and shales represent lagoons. Up-section, the middle Eocene marl beds likely deposited on a tidal flat. The late Eocene/Oligocene basal Murree beds, containing tidal bundles, indicate that a mixed or semi-diurnal tidal system deposited the sediments and the sedimentation took place in a tide-dominated estuary. In the higher-up, the succession likely deposited in a river-dominated estuary or in meandering rivers. In the beginning of the basin evolution, the sediments were derived from the Precambrian basement or from the metasediments/volcanic rocks possessing terrains of the south. The early and middle Eocene (54.7–41.3 Ma succession of the embryonic foreland possibly developed from the sediments derived from the Trans-Himalayan schists and phyllites and Indus ophiolite of the north during syn-collisional stage. The detrital minerals especially the lithic fragments and the heavy minerals suggest the provenance for the late Eocene/Oligocene sequences to be from the recycled orogenic belt of the Higher Himalaya, Tethyan Himalaya and the Indus-suture zone from the north during post-collisional stage. This is also supported by the paleocurrent

  20. Physiological strain in the Hungarian mining industry: The impact of physical and psychological factors

    Directory of Open Access Journals (Sweden)

    József Varga

    2016-08-01

    Full Text Available Objectives: The objectives of these investigations completed on workplaces in the Hungarian mining industry were to characterize the physiological strain of workers by means of work pulse and to examine the effects of work-related psychological factors. Material and Methods: Continuous heart rate (HR recording was completed on 71 miners over a total of 794 shifts between 1987 and 1992 in mining plants of the Hungarian mining industry using a 6-channel recorder – Bioport (ZAK, Germany. The work processes were simultaneously documented by video recording along with drawing up the traditional ergonomic workday schedule. All workers passed health evaluation for fitness for work. The effects of different psychological factors (simulated danger, “instrument stress,” presence of managers, and effect of prior involvement in accidents as well as different mining technologies and work place illumination on the work pulse were evaluated. The statistical analysis was completed using SPSS software (version 13.0, SPSS Inc., USA. Results: The work-related physiological strain differed between work places with different mining technologies in groups of 12–18 workers. The work pulse was lowest in bauxite mining (ΔHR = 22±8.9 bpm and highest in drift drilling in dead rock with electric drilling machine (ΔHR = 30±6.9 bpm. During sham alarm situation the work pulse was significantly higher than during normal activities with the same physical task (ΔHR = 36.7±4.8 bpm vs. 25.8±1.6 bpm, p < 0.001. When work was performed under different psychological stress, the work pulse was consistently higher, while improving the work place illumination decreased the physiological strain appreciably (ΔHR (median, 25–75 percentiles = 23, 20–26 bmp vs. 28, 25–31.3 bpm, p < 0.001. Conclusions: Recording the heart rate during whole-shift work along with the work conditions gives reliable results and helps isolating factors that contribute to increased strain. The

  1. Preparation and Application of Special Silicon Mullite Brick for Cement Kiln%水泥窑用特种硅莫砖的研制及应用

    Institute of Scientific and Technical Information of China (English)

    刘振英; 姚峰

    2012-01-01

    以高铝矾土熟料、90碳化硅、棕刚玉为主要原料,添加红柱石粉、广西白泥等外加剂,通过合理的颗粒级配,采用高压成型、高温烧成等方法,制备出水泥窑用特种硅莫砖,并研究了烧成后试样的体积密度、气孔率、强度、微观结构和耐磨性.结果表明:添加6%红柱石粉在1420℃制备的硅莫砖的性能最优,其体积密度为2.74 g/cm3,抗热震性30次,磨损量为1.06 cm3,热导率为1.65 W/(m·K),耐压强度高达159 MPa,在5000 t/d水泥回转窑过渡带上使用该产品,寿命可达一年以上,这是由于窑简体外表面温度比使用镁尖晶石砖平均降低80℃以上,极为有效地延长了该砖衬的使用寿命.%Special silicon mullite brick for cement kiln was prepared by the production technology of proper particle size grading,high pressure pressing and high temperature sintering using bauxite clinke,90 silicon carbide and brown alundum as raw materials, and andalusite powder and guangxi white clay as additives. The bulk density, apparent porosity, strength, microstructure and abrasion resistance of the sintered materials were investigated. The results showed that the sample sintered at 1420 t whose andalusite powder content was 6% was of good properties on bulk density of 2. 74 g/cm3, thermal conductivity of 1.65 W/ ( m · K ) , thermal shock resistance of 30 times, abrasion volume loss of 1.06 cm3 and compressive strength of 159 Mpa. When the brick were used in the transition zone of cement kiln,the service life of it was more than a year and a half .which was due to the cement kiln surface temperature of special silicon mullite brick was lower (average decreasing 80 X.) than that of magnesium spinel brick and the service life of special silicon mullite brick was prolonged effectively.

  2. Structural and Geomorphic Controls on Dryland Salinity and Regolith Distribution in the Critical Zone, North-east Tasmania, Australia.

    Science.gov (United States)

    Sweeney, M. E.; Moore, C. L.

    2015-12-01

    Salinity occurs in the drier and flatter Australian landscapes because there is insufficient rain to flush salts from critical zone. Changes in land use due to agriculture and urbanisation can accelerate salinity effects, leading to soil and water degradation and threatening infrastructure and ecosystems. The dominant lithology in the salt affected regions of North-east Tasmania is dolerite. The geochemistry of dolerite regolith has been examined in order to understand the association between salinity and weathered dolerite. The electrical conductivity of 1:5 soil-waters is higher in the more weathered material (maximum 4.9 dS/m). This confirms field observations that highly weathered dolerite can serve as a significant store for salt in the landscape. However, the clay content and salinity varies, depending on the local geomorphic context. Dolerite weathering on well-drained slopes has favoured the formation of 1:1 kaolinite clays, and sometimes bauxite formation. Kaolinite-bearing regolith can store salt via matrix diffusion processes. However, there are fault-bounded pockets of colluvium and highly-weathered in situmaterial, where the supply of cations has not been diminished and 2:1 montmorillonite clays dominate. These regions have the capacity to store large volumes of salts. The geomorphology also affects the volume of rain and flux of salt from windblown dust and oceanic aerosols. The chemistry of rainwater from an array of bulk deposition collectors was studied from Spring 2013 to Winter 2014. The average salt flux was 79± 10 kg/ha/yr in the study region, ranging from 170± 12 kg/ha/yr in the north to 42 ± 6 kg/ha/yr inland. To assist in understanding why salt is found in certain parts of the landscape but not in others, it is essential to model how water moves through the critical zone and geological structures. By exploring the complex interactions of geomorphology and other biophysical parameters the study area has been divided into Hydrogeological

  3. No short-term cytogenetic consequences of Hungarian red mud catastrophe.

    Science.gov (United States)

    Gundy, Sarolta; Farkas, Gyöngyi; Székely, Gábor; Kásler, Miklós

    2013-01-01

    Red mud is an industrial waste produced in the process of alumina extraction from bauxite with concentrated NaOH. When the red mud-containing reservoir collapsed in Ajka Alumina Plant Hungary in October 2010, the most serious immediate effects were caused by the high alkalinity (pH ≥ 13) of the flood. Many persons suffered burn-like damage to tissues and contact with caustic desiccated ultra-fine dust with traces of toxic metals also caused irritation of upper respiratory tract and eyes. This catastrophe was unique from the point of view of genotoxic effects as well. Therefore cytogenetic examinations were carried out on inhabitants, either with burns (17 persons) or on those inhaling desiccated caustic dust (42 persons). Chromosomal aberration (CA) analysis and bleomycin (BLM)-sensitivity assays, as possible markers of effects, were studied in peripheral blood lymphocytes of persons within 4-6 weeks following the catastrophe. Controls were matched for age, sex and smoking habits, and also places of residence with different constituents of air pollution either from rural (59 persons), or from urban environments (59 persons). Neither spontaneous rate of CAs (1.47% vs. 1.69%) nor BLM-induced in vitro chromosomal breakage (0.79 vs. 0.83 break/cell) showed elevated rates when cytogenetic biomarkers of genotoxicity were compared between controls and exposed persons. Time spent in cleaning did not affect cytogenetic changes either (R(2) = 0.04). BLM-induced mutagen sensitivity was similar in exposed and control persons (27.1% vs. 30.5%). It seems that the red mud exposure does not appear to pose an immediate genotoxic hazard on residents when measured with cytogenetic methods. We recommend, however, that those involved in clean-up activities should be followed closely not only for overall health, but also for further genotoxic risk assessment, because the long-term hazards of ultra-fine fugitive dust particles with alkalinity of residual NaOH in red mud are still

  4. Gypsum addition to soils contaminated by red mud: implications for aluminium, arsenic, molybdenum and vanadium solubility.

    Science.gov (United States)

    Lehoux, Alizée P; Lockwood, Cindy L; Mayes, William M; Stewart, Douglas I; Mortimer, Robert J G; Gruiz, Katalin; Burke, Ian T

    2013-10-01

    Red mud is highly alkaline (pH 13), saline and can contain elevated concentrations of several potentially toxic elements (e.g. Al, As, Mo and V). Release of up to 1 million m(3) of bauxite residue (red mud) suspension from the Ajka repository, western Hungary, caused large-scale contamination of downstream rivers and floodplains. There is now concern about the potential leaching of toxic metal(loid)s from the red mud as some have enhanced solubility at high pH. This study investigated the impact of red mud addition to three different Hungarian soils with respect to trace element solubility and soil geochemistry. The effectiveness of gypsum amendment for the rehabilitation of red mud-contaminated soils was also examined. Red mud addition to soils caused a pH increase, proportional to red mud addition, of up to 4 pH units (e.g. pH 7 → 11). Increasing red mud addition also led to significant increases in salinity, dissolved organic carbon and aqueous trace element concentrations. However, the response was highly soil specific and one of the soils tested buffered pH to around pH 8.5 even with the highest red mud loading tested (33 % w/w); experiments using this soil also had much lower aqueous Al, As and V concentrations. Gypsum addition to soil/red mud mixtures, even at relatively low concentrations (1 % w/w), was sufficient to buffer experimental pH to 7.5-8.5. This effect was attributed to the reaction of Ca(2+) supplied by the gypsum with OH(-) and carbonate from the red mud to precipitate calcite. The lowered pH enhanced trace element sorption and largely inhibited the release of Al, As and V. Mo concentrations, however, were largely unaffected by gypsum induced pH buffering due to the greater solubility of Mo (as molybdate) at circumneutral pH. Gypsum addition also leads to significantly higher porewater salinities, and column experiments demonstrated that this increase in total dissolved solids persisted even after 25 pore volume replacements. Gypsum

  5. Study on particle-size separation pretreatment of Bayer red mud%拜耳法赤泥粒径分级预处理的研究

    Institute of Scientific and Technical Information of China (English)

    刘万超; 张校申; 江文琛; 朱新锋; 杨家宽

    2011-01-01

    赤泥是从铝土矿中提取氧化铝的过程中产生的工业废渣.分析了拜耳法赤泥的粒径分布,以及主要化学组成和矿物组成在不同粒径赤泥中的变化规律.在此基础上,提出先将赤泥粒径分级预处理,然后根据粗细粒径赤泥的差异分别进行回收利用的思路.研究结果表明,赤泥中粒径大于0.075 mm的粗颗粒以铁、硅、钙为主,实践证明可以通过磁选或重选工艺直接从中回收铁矿;赤泥中粒径小于0.075 mm的细颗粒占赤泥总质量的74.31%,其铝硅比(A/S)由原来的0.81提高到1.08,初步实验证明可以利用还原焙烧-溶出-磁选工艺联合回收铁铝元素.分析认为,该预处理过程具有较好的环境效益.%Red mud is the solid waste generated in alumina extracting process from bauxite. The different chemical compositions and mineral phases in Bayer red mud with different size range were investigated. A size separation pretreatment process followed by recovery of value elements from red mud with different size range was proposed. The results show that iron, silicon and calcium are the three dominating compositions in the large particles ( ≥0. 075 mm) from raw red mud. Iron ore can be directly enriched from the bulk particles by magnetic separation or gravitational separation. The content of small particles ( < 0. 075 mm) in raw red mud is 74.31% by weight. The massive ratio of Al2O3 to SiO2 (A/S) in small particle is improved to 1.08 from 0.81 of raw red mud. Primary experiments show that it is possible to recover Fe and Al from fine red mud by reducing roast-dissolution-magnetic separation technique. And it is believed that the pretreatment process is positive to environment protection.

  6. Fundamental properties of industrial hybrid cement: utilization in ready-mixed concretes and shrinkage-reducing applications

    Directory of Open Access Journals (Sweden)

    Martauz, P.

    2016-06-01

    Full Text Available Utility properties of novel hybrid cement (H-Cement are influenced by pozzolanic reaction of fly ash, latent hydraulic reaction of metallurgical slag together with the alkali activation of inorganic geopolymer based on precipitated waste water coming from bauxite residues. Content of Portland cement clinker is at maximum of 20 mass %, the remaining portion consists of inorganic geopolymer. Up to 80% of CO2 emissions are saved by H-Cement manufacture compared to ordinary Portland cement (OPC. No heat treatment or autoclaving is needed at H-Cement production. The field application of H-Cement is performed by the same way than that of common cements listed in EN 197-1, and is also connected with highly efficient recovery and safe disposal of red mud waste. H-Cement is suitable for ready-mixed concretes up to C30/37 strength class and is specified by beneficial shrinkage-reducing property of the concrete kept in long dry-air cure opposite to common cements.Las propiedades de un nuevo cemento híbrido (cemento-H vienen determinadas por la reaccion puzolánica de cenizas volantes, la hidráulica latente de las escorias metalúrgicas y la activación alcalina mediante las aguas residuales generadas por el tratamiento de la bauxita para dar un geopolímero inorgánico. La proporción máxima de clínker de cemento en este nuevo material es del 20%, y por ello, en su fabricación se emite hasta un 80% menos de CO2 que en la producción del cemento portland (OPC. El cemento-H se prepara sin necesidad de tratamiento térmico ni de estancia en autoclave y su aplicación es la misma que los cementos convencionales definidos en la norma EN 197-1. Por otra parte, su fabricación supone la recuperación y la valorización segura de los lodos rojos de bauxita. El cemento-H es apto para la preparación de hormigones premezclados hasta la categoría C30/37, presentando el nuevo material, además, una menor retracción que los cementos convencionales, por lo que su

  7. Development and Application of High Strength Free Baking Scorched Stones Mullite Coating%铝合金炉用微孔高抗渗透高铝浇注料的研制及应用

    Institute of Scientific and Technical Information of China (English)

    张成行; 冉江艳; 宋洪武

    2016-01-01

    本浇注料是由特级转窑矾土熟料为主材, CA-70水泥, SiO2超微粉、α-Al2 O3微粉为结合剂、加入适量的膨胀剂,反润湿剂和减水剂等配制而成。试验结果表明:本微孔高抗渗高铝浇注料不仅气孔率低、气孔孔径小,耐铝合金液态或汽态元素的渗透和侵蚀,而且机械强度高,高温体积稳定,热震性能好,并且有效地避免了三相交界处结瘤、鼓包现象。2012年7月份在某铝厂40 t铝合金炉上使用,至今无剥落,无裂纹,无结瘤,经济、社会效益显著,具有推广应用价值。%The castable is composed of super rotary kiln bauxite as main material, CA-70 cement, SiO2 ultrafine powder,α-Al2 O3 powder adding expansion agent amount as binder, reverse wetting agent and water reducing agent was prepared. The test results showed that the porous high impermeability of high alumina castable had low porosity, small pore size, infiltration and erosion resistance of aluminum alloy in liquid or vapor form elements, and high mechanical strength, high volume stability, thermal shock performance, and effectively avoided the three-phase boundary of nodulation, bulge phenomenon. In July 2012, 40 tons of aluminum alloy furnace were used in an aluminum, so far it had no peeling off, no crack, no nodulation, economic, social benefits significantly, and had popularization and application value.

  8. Natural resources as a factor of economic growth in Kosovo

    Directory of Open Access Journals (Sweden)

    Haki Shatri

    2015-11-01

    accompanying products like bauxite, iron-nickel, manganese, copper, chromium and rare metals (The Republic of Kosovo Government, 2009. The mining industry around the world is increasing. Production and consumption of the energy as well. Prices on the world market with the exception of small tremors are favorable. Therefore the country needs development policies based on the use of these resources since they can become the sector for economic development of the country in the future.

  9. Experimental study and mechanism analysis of modified limestone by red mud for improving desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongtao; Han, Kuihua; Niu, Shengli; Lu, Chunmei; Liu, Mengqi; Li, Hui [Shandong Univ., Jinan (China). School of Energy and Power Engineering

    2013-07-01

    Red mud is a type of solid waste generated during alumina production from bauxite, and how to dispose and utilize red mud in a large scale is yet a question with no satisfied answer. This paper attempts to use red mud as a kind of additive to modify the limestone. The enhancement of the sulfation reaction of limestone by red mud (two kinds of Bayer process red mud and one kind of sintering process red mud) are studied by a tube furnace reactor. The calcination and sulfation process and kinetics are investigated in a thermogravimetric (TG) analyzer. The results show that red mud can effectively improve the desulfurization performance of limestone in the whole temperature range (1,073-1,373K). Sulfur capacity of limestone (means quality of SO{sub 2} which can be retained by 100mg of limestone) can be increased by 25.73, 7.17 and 15.31% while the utilization of calcium can be increased from 39.68 to 64.13%, 60.61 and 61.16% after modified by three kinds of red mud under calcium/metallic element (metallic element described here means all metallic elements which can play a catalytic effect on the sulfation process, including the Na, K, Fe, Ti) ratio being 15, at the temperature of 1,173K. The structure of limestone modified by red mud is interlaced and tridimensional which is conducive to the sulfation reaction. The phase composition analysis measured by XRD of modified limestone sulfated at high temperature shows that there are correspondingly more sulphates for silicate and aluminate complexes of calcium existing in the products. Temperature, calcium/metallic element ratio and particle diameter are important factors as for the sulfation reaction. The optimum results can be obtained as calcium/metallic element ratio being 15. Calcination characteristic of limestone modified by red mud shows a migration to lower temperature direction. The enhancement of sulfation by doping red mud is more pronounced once the product layer has been formed and consequently the promoting

  10. Megafauna of vulnerable marine ecosystems in French mediterranean submarine canyons: Spatial distribution and anthropogenic impacts

    Science.gov (United States)

    Fabri, M.-C.; Pedel, L.; Beuck, L.; Galgani, F.; Hebbeln, D.; Freiwald, A.

    2014-06-01

    impacts show that seafloor disturbance by benthic fishing is mainly attributable to trawling in the Gulf of Lion and to long lines where rocky substrates are present. The bauxite residue (red mud) expelled in the Cassidaigne canyon was seen to prevent fauna from settling at the bottom of the canyon and it covered much of the flanks. Litter was present in all of the canyons and especially in considerable quantities in the Ligurian Sea, where the heads of the canyons are closer to the coast. Three Marine Protected Areas and one fishing area with restricted access have recently been established and should permit the preservation of these deep ecosystems.

  11. Les formations marines et continentales intervolcaniques des îles Canaries orientales (Grande Canarie. Fuerteventura et Lanzarote: Stratigraphie et signiflcation paleoclimatique.

    Directory of Open Access Journals (Sweden)

    Meco, J.

    1985-08-01

    Full Text Available More than 20 m. y. of continuous activity in the Canary Islands have brought about the fossilization of marine fauna and soils which prove the existence of alternating warm and numid conditions of guinean origen, and also of drier influences from the Sahara, connected with the arrival of cold waters from the Lusitanian Sea. The sea deposits of the lower Pleistocene with Strombus coronatus and those of the upper Pleistocene with Strombus bubonius, which are caracteristically warm and the deposits of middle and upper Pleistoeene and of the Holocene, with various species of Patella and caracteristically cold (Meco, 1977, have already been related to volcanic activities dated by K/Ar (Meco y Steams, 1981 and are new being related to rapid effects of soil formation, the result of evaporation an clayey neoformation of volcanic materials which are constantly being renoved. The fairly rapid fossilization caused by volcanic activity, eliminates some of the effects accumulated over a period of time on the paleosoils, The existence of Saharian quartz, a mineral not found in volcanic products, and the simultaneous existence of more distant matters on the evolution of soilformation, like crusts which contain gypsum or attapulgyte of desert origin and bauxites containing nickel and tale of tropical, humid origin (Pomel, 1985, all this permit to find coherents conclusions.

    Más de 20 m. a. de actividad volcánica continuada ha permitido en las Canarias la fosilización de faunas marinas y suelos que testimonian una alternancia de condiciones cálidas y húmedas, de origen guineano, y de influencias secas, saharianas, relacionadas con aportes de aguas frescas de procedencia lusitana. Los depósitos marinos del Plioceno inferior con Strombus coronatus y los del Pleistoceno superior con Strombus bubonius, que revelan un carácter cálido, y los depósitos del Pleistoceno medio y superior y del Holoceno, con varias

  12. 全球成矿域和成矿区带%Global metallogenic domains and districts

    Institute of Scientific and Technical Information of China (English)

    梅燕雄; 裴荣富; 杨德凤; 戴自希; 李进文; 徐丛荣; 瞿泓滢

    2009-01-01

    -Mongolia, Siberia and Sino-Ko-rea. it is characterized by large-scale mineralizations of natural gas, coals, iron, potash salt, oil, uranium, manganese, chromium, lead, zinc, nickel, tungsten, molybdenum, antimony, gold, silver, phosphorus and diamond. The metallogenic epochs run through all the geological ages, mainly Paleozoic and subordinately Mesozoic and Proterozoic. Lying in the southern part of the earth, the Gondwana metallogenic domain runs across South America, Africa, Oceania and Asia and comprises five gigantic metallogenic districts, namely, South America, Africa-Arabia, India, Australia and Antarctic. It is featured by large-scale mineralizations of oil, gas, bauxite, diamond, lead, zinc, copper, nickel, iron, gold, chromium, tin and uranium. The metallogenic epochs also go through all the geological ages, with Proterozoic and Cenozoic being dominant, and Archean and Mesozoic possessing the subordinate importance. Running across the central part of the earth, the Tethys metallogenic domain straddles North America, Europe, Africa and Asia and is made up of five gigantic metallogenic districts, namely, Caribbean, Mediterranean, West Asia, Himalaya and Indo-China Peninsula. It is characterized by large-scale mineralizations of tin, potash salt, lead, zinc, bauxite, copper and molybdenum. The metallogenic epochs are dominated by Mesozoic-Cenozoic. Distributed around the Pacific Ocean, the circum-Pacific metallo-genic domain straddles Asia, Oceania, North America and South America and consists of five gigantic metallogenic districts, namely, North Cordilleran, Andean, Chokochi-Okhotsk, East Asia and Irian-New Zealand. It is characterized by large-scale mineralizations of copper, molybdenum, gold, silver, nickel, tungsten, tin, lead and zinc. The most important metallogenic epochs are Mesozoic-Cenozoic.

  13. 含镁铝尖晶石的铝酸盐水泥的制备及其抗侵蚀性%PREPARATION AND CORROSION RESISTANCE OF ALUMINOUS CEMENT CONTAINING MAGNESIUM ALUMINATE SPINEL

    Institute of Scientific and Technical Information of China (English)

    肖国庆; 高云琴; 段锋

    2008-01-01

    以白云石和工业Al2O3为原料,采用烧结法制备了含镁铝尖晶石的铝酸盐新型水泥,利用X射线衍射检测了合成产物的物相组成,采用扫描电子显微镜观察了新型铝酸盐水泥中各物相的形貌和能谱分析了成分分布,测量了这种铝酸盐水泥的凝结时间、耐火度以及其所结合的高铝矾土制成的耐火浇注料的早期强度.选择静态坩埚法进行抗渣性实验,对比了新型铝酸盐水泥和纯铝酸钙水泥结合刚玉浇注料的抗渣性差异.结果表明:这种水泥的物相组成为镁铝尖晶石、一铝酸钙和二铝酸钙;物相分布较为均匀.与纯铝酸钙水泥比较,凝结时间正常,新型铝酸盐水泥结合刚玉浇注料与纯铝酸钙水泥结合刚玉浇注料的抗弯强度相当,耐火度较高和抗侵蚀性较好,其原因在于水泥中存在镁铝尖晶石相,而镁铝尖晶石有较高的熔点和抗熔渣侵蚀能力.%A new type of aluminous cement containing magnesium aluminate (MA) spinel was prepared from mixtures of dolomite and alumina by a sintering process. The microstructures and phase constituents of the synthesized product were inspected by X-ray diffraction and scanning electron microscope with energy dispersive X-ray spectrometry. The setting time, refractoriness and bonding strength of the new type of aluminous cement were measured by means of standard methods. The corrosion resistance property was also investigated by static crucible method. The experimental results show that the new type of aluminous cement consists of MA spinel, calcium monoaluminate and calcium dialuminate phases. Compared with aluminous cement, the prepared cement with more uniform phase distribution has a reasonable setting time, and the cement containing MA spinel bonded castables with bauxite as an aggregate have considerable bonding strength, higher refractoriness and better corrosion resistance. This is due to the introduction of MA spinel, which has a high

  14. 成型压力与热处理温度对合成镁铝尖晶石材料的影响%Effects of molding pressure and heat treatment temperature on synthesis of magnesium aluminate spinel material

    Institute of Scientific and Technical Information of China (English)

    田玉明; 陈战考; 周少鹏; 李秋书; 柴跃生; 吕德富; 李晓松

    2014-01-01

    以特级铝矾土和轻质氧化镁为主要原料,按m(Al2 O3)m(MgO)=2.54配料,采用一步烧结法制备尖晶石材料,研究了成型压力(分别为25、50、75、100、125、150 MPa)和热处理温度(分别为1250、1300、1350、1400、1450、1500、1550℃)对合成材料的物相组成、显微结构、体积密度、显气孔率、荷重软化温度的影响。结果表明:1)以50 MPa压力成型的试样在1450℃保温4 h热处理后显气孔率最小,以100、125和150 MPa成型的试样在1450℃保温4 h热处理后存在开裂或扭曲现象;2)1250~1550℃热处理后试样的主晶相均为MgAl2 O4,MgAl2 O4晶粒随热处理温度的升高逐渐发育完整并长大;3)随着热处理温度的升高,试样的致密度逐渐升高,但以1400℃为转折点,致密度升高速率前高后低;4)随着热处理温度的升高,试样的荷重软化温度逐渐升高。%Magnesium-aluminate spinel materials were prepared by one-step sintering process with special grade bauxite and light weight magnesia as main starting materials with the ratio of m(Al2 O3 )m(MgO)=2.54.Effects of molding pressure (25,50,75,100,125,and 150 MPa)and heat treatment temperature (1 250,1 300,1 350,1 400,1 450,1 500,and 1 550 ℃)on phase compositions,microstructure,bulk density, apparent porosity,and refractoriness under load of specimens were studied.The results show that:(1 )the specimen pressed under 50 MPa and fired at 1 450 ℃ for 4 h has the lowest apparent porosity,while the specimens pressed under 100,125,and 150 MPa fired at 1 450 ℃for 4 h crack or distort;(2)the specimens fired at 1 250-1 550 ℃ have main crystal phase of MgAl2O4,and the MgAl2O4 crystals develop and grow as heat treatment temperature rises;(3)as heat treatment temperature rises,the bulk density of specimens increases,and the increasing rate slows down after 1 400 ℃;(4)as heat treatment temperature rises,the refractoriness under load

  15. Using a robotics competition to teach about and stimulate enthusiasm for Earth science and other STEM topics

    Science.gov (United States)

    Fike, Hildee; Barnhart, Paul; Brevik, Corinne E.; Brevik, Eric C.; Burgess, Cynthia; Chen, Jundong; Egli, Shawna; Harris, Billy; Johanson, Paul J.; Johnson, Naomi; Moe, Marie; Olsen, Reba

    2016-04-01

    One of the major challenges in recruiting students to careers in STEM (science, technology, engineering, and mathematics) fields is to stimulate enthusiasm about these fields in our youth. BEST (Boosting Engineering Science and Technology) Robotics is a national program in the USA that attempts to recruit junior and senior high school students (ages 13-18) into STEM careers by showing youth how exciting these careers can be by using robotics competitions. The competitions have several aspects, including robot design, software engineering, marketing, public outreach, research into the subject area of the year's tasks, and a set of tasks to be physically performed by the robots that each team builds. The tasks to be performed change every year; therefore, even teams that compete over multiple years must build a new robot each year designed to perform the particular tasks charged to them. Dickinson State University is the home to Blue Hawk BEST, one of the hubs that host the first round of competition for teams hoping to move on to regional, and potentially, national level competition. The tasks for 2015 revolved around a mining theme. The robots needed to be able to replace the filter in an air filtration system, fix broken pipes, mine simulated aggregate, coal, magnetite, bauxite, chalcopyrite, and spodumene, and move core samples. Points were awarded for successful progress toward each task based on the difficulty of the task and the market value of the commodities. While several STEM fields are covered in various aspects of the competition, the 2015 competition includes Earth science in that the students are required to research the history and science of the commodities being mined and learn about ways the commodities are important to their lives and the economy of their particular region. Several awards are handed out to the top performing teams in various categories, including spirit and sportsmanship awards. As teams compete for these awards a raucous

  16. Steel desulphurization with synthetic slag

    Directory of Open Access Journals (Sweden)

    Heput, T.

    2007-02-01

    Full Text Available Generally speaking, sulphur is considered a harmful element for steel quality, reason why all the technological steps are being taken in order to eliminate it from the metal bath. This paper deals with the influence of the chemical composition, on the slag quantity and of the bath stirring condition upon the desulphurization process in the casting ladle by treatment with synthetic slag. The experiments were made at an open-hearth plant with the steel tapping in two ladles (the desulphurization was made with synthetic slag at one ladle while the other one was considered standard and at the electric steel plant and for the synthetic slag formation a mix was used, made, according to several receipts, of: lime (50-75%, fluorine (0-17%, bauxite (0-32% and aluminous slag (8-22%. The data were processed in the calculation programs EXCEL and MATLAB, which resulted in a series of correlations between the desulphurization degree and the chemical composition of the slag, respectively the slag quantity both for the charges bubbled with Argon and the unbubbled ones.

    En general, el azufre es considerado un elemento nocivo para la calidad del acero y, por eso, en la práctica, se toman todas las medidas de orden tecnológico para su eliminación del baño metálico. En este trabajo se analiza la influencia de la composición química, de la cantidad de escoria y del estado de agitación del baño sobre el proceso de desulfuración en la cuchara para fundir por tratamiento con escoria sintética. Los experimentos se han realizado en una acería evacuando el acero en dos ollas (en una cuchara se efectuó la desulfuración con escoria sintética y a la otra se consideró como patrón y en un acería eléctrica y para la formación de la escoria sintética se utilizó una mezcla producida según muchas recetas, formada por: cal (50-75%, fluorina (0-17%, bauxita (0-32% y escoria aluminosa (8-22%. Los datos han sido procesados en los programas de c

  17. Enhancing the hydrogeological landscape (HGL) characterisation of the Greater Launceston area (GLA) through better understanding of dolerite weathering, stream water properties and a revised landscape evolution model

    Science.gov (United States)

    Moore, Leah; Nicholson, Allan; Cook, Wayne; Sweeney, Margaret

    2014-05-01

    In the Greater Launceston Area (GLA) in northern Tasmania, Australia, there is a widespread urban salinity problem with severe impacts on urban/peri-urban infrastructure in localised areas. Salinity patterns in the landscape (elevated flux to waterways; salt efflorescence at the land surface) could be related to: the underlying rock type, the thickness of regolith materials and hence the volume of the salt store, the landforms present and the amount of water passing over and through the landscape. In northern Tasmania secondary mineralogy on dolerite typically includes formation of Fe/Ca smectite phases (e.g. nontronite, saponite) and Fe-Ti oxides/sesquioxides (e.g. hematite, goethite) with some primary phases (e.g. Ca-plagioclase feldspar, augite) weathering through to a suite dominated by kaolinite clay and Fe-Ti oxides/sesquioxides. Deeply weathered profiles in the GLA have weathered to the kaolintite-clay dominant mineralogy and in places there are gibbsite/beidellite/hematite/goethite bauxites developed. Most existing salinity mapping emphasises salt manifestation over paleo-estuarine sediments of the Paleogene Tamar-Esk River system, so incorporation of deeply weathered Jurassic dolerite materials into the salt budget considerably augments the estimated potential hazard. Rapid stream surveys provide a snapshot of stream electrical conductivity (EC) over the study area at regular intervals allowing a broad evaluation of salt flux patterns in surfaces waters. Higher EC readings were obtained from selected streams draining: deeply weathered dolerite profiles (0.37 1.86 dS/m) and deeply weathered Paleogene paleo-estuarine sediments (0.49 to 1.16 dS/m). Lower values were measured on up-faulted dolerite blocks (development of a more comprehensive and consistent landscape evolution model that builds on existing knowledge. This model describes the influence of a progressively incising Tamar-Esk river system in response to episodic lowering of the local base level

  18. Utilização de alumina para a remoção de fluoretos em águas e efluentes The use of alumina to remove fluorine from water and effluents

    Directory of Open Access Journals (Sweden)

    S. B. Alvarinho

    2000-06-01

    Full Text Available Foram produzidos 12 tipos de adsorventes de flúor a base de alumina granular seguindo duas rotas de processamento distintas. A primeira rota consistiu na precipitação de hidróxido de alumínio utilizando a técnica de sol-gel e a obtenção de microesferas por geleificação interna e externa. Utilizou-se como matéria prima nitrato de alumínio. A segunda rota consistiu na micropelotização mecânica utilizando-se hidróxido de alumínio produzido pelo processo Bayer e o uso de bauxita. Microesferas e micropelotas foram submetidas a diferentes tratamentos térmicos e avaliadas quanto ao seu desempenho no processo de adsorção de flúor em água. Os adsorventes produzidos no presente trabalho apresentaram parâmetros cinéticos e de carga de flúor superiores aos adsorventes de alumina reportados na literatura. Os adsorventes na forma de micropelotas apresentaram propriedades similares aos obtidos pela técnica de sol-gel. O maior valor relacionado à adsorção de flúor (100 h-1 foi obtido com microesferas de alumina produzidas pelo processo de geleificação interna, posteriormente calcinadas a 550 ºC. Microesferas de alumina contendo carvão ativo foram também preparadas e apresentaram capacidade de adsorção de flúor relativamente elevada (88 h-1. Micropelotas de alumina calcinadas a 400 ºC apresentaram a maior razão de flúor adsorvido por tonelada de adsorvente (27855.Twelve different types of fluorine adsorbents based on alumina granules were produced following two processing routes. The first route consisted on the precipitation of aluminum hydroxide by sol-gel technique followed by microsphere production by internal and external gelation. Aluminum nitrite was used as raw material. The second route consisted on the mechanical micro pelletization of aluminum hydroxide produced by the Bayer process, and bauxite. Microspheres and micropellets were heat treated at different conditions and their fluorine adsorption performance

  19. Estudo das reações alcalis-sílica associadas ao uso da lama vermelha em argamassas colantes e de revestimento Study of alkali-silica reactions associated with the use of red mud in plastering mortars

    Directory of Open Access Journals (Sweden)

    D. V. Ribeiro

    2012-03-01

    Full Text Available A incorporação de resíduos industriais em matrizes cimentícias, com o objetivo de inertização, é uma alternativa de reutilização que tem sido bastante estudada nos últimos anos. No presente trabalho, estudou-se a lama vermelha, resíduo sólido gerado no processo de beneficiamento da bauxita e que, devido a seu elevado pH, é considerado "perigoso". Apesar do uso deste resíduo ter sido reportada em trabalhos anteriores, algumas patologias podem estar associadas à sua utilização, devido à elevada concentração de íons alcalinos (principalmente o sódio, favorecendo as reações álcalis-sílica (RAS e às dificuldades de moldagem (reologia devido à elevada finura deste resíduo. Apesar destes prováveis problemas provenientes do uso indiscriminado da lama vermelha como adição às argamassas e concretos, ainda são poucas as pesquisas que os contemplam, sendo este o foco do presente trabalho. Foram verificadas as propriedades reológicas das argamassas, utilizando um reômetro e a avaliação da RAS, de acordo com as normas ASTM C 1260-07 e NBR 11582. Os resultados obtidos foram bastante satisfatórios quanto ao comportamento das argamassas frente à RAS, apesar da elevada concentração de álcalis na lama vermelha, com grande influência reológica.The incorporation of industrial wastes in cementitious matrices, with the goal of inertization, is an alternative of reuse that has been extensively studied in recent years. In this paper, the red mud, the main waste generated in aluminum and alumina production by the Bayer process from bauxite ore and considered "hazardous" due to the high pH, was studied. Despite the use of this waste have been reported in previous studies, some pathologies may be associated with its use, due to high concentration of alkali ions (mainly sodium, favoring the alkali-silica reactions (ASR and the difficulties of molding (rheology because of high fineness of this waste. Despite these potential

  20. 中国耐火材料工业的崛起%Uprise of China' s refractories industry

    Institute of Scientific and Technical Information of China (English)

    钟香崇

    2013-01-01

    The development of refractories industry in China in the past 62 years is reviewed and further development in the next 30 years is discussed. In 1949-1979,China' s refractories industry gradually developed from originally backward status to be a comprehensive industrial sector with sizable production capacity and elevated technical level. In 1979-2010,refractories production increased at fast tempo,reaching 25.4 million tons in 2010 and ranking top in the world. Important progress was made in innovative research and development on high quality synthetic refractory raw materials based on bauxite and magnesite and high performance new products with Chinese characteristics such as oxide-nonoxide composites. The next 30 years (2011-2040) should be a period of steady development. More efforts should be given to efficient utilization of natural resources,product quality,environmental protection and energy conservation and development in science and technology. Future work should be focused on the following three strategic tasks: (1) reorganization and reconstruction of refractories mining enterprises;(2)structural adjustment and optimization of refractories manufacturing companies;(3)innovative achievements in refractories science and technology.%简要总结了我国耐火材料工业62年来取得的成就,并讨论了今后30年的发展方向:1949-1979年为从无到有的初步发展时期,耐火材料工业从原来的落后状态逐步发展成为具有一定生产规模和较高技术水平的产业部门;1979-2010年为从小到大的快速发展时期,全国耐火材料产量快速增长到2 543万t,跃居世界首位,而且自主创新科研工作进展较好,有的已转化为生产力并走向产业化,如矾土基合成料和氧化物-非氧化物复合材料;今后30年(2011-2040年)将是耐火材料工业从大到强的稳健发展时期,要致力于提高矿产资源利用,提高产品质量,促进节能减排,促进科技发展,为此要抓紧抓

  1. Geochemistry of Selected Coal Samples from Sumatra, Kalimantan, Sulawesi, and Papua, Indonesia

    Science.gov (United States)

    Belkin, Harvey E.; Tewalt, Susan J.

    2007-01-01

    Introduction Indonesia is an archipelago of more than 17,000 islands that stretches astride the equator for about 5,200 km in southeast Asia (figure 1) and includes major Cenozoic volcano-plutonic arcs, active volcanoes, and various related onshore and offshore basins. These magmatic arcs have extensive Cu and Au mineralization that has generated much exploration and mining in the last 50 years. Although Au and Ag have been mined in Indonesia for over 1000 years (van Leeuwen, 1994), it was not until the middle of the nineteenth century that the Dutch explored and developed major Sn and minor Au, Ag, Ni, bauxite, and coal resources. The metallogeny of Indonesia includes Au-rich porphyry Cu, porphyry Mo, skarn Cu-Au, sedimentary-rock hosted Au, epithermal Au, laterite Ni, and diamond deposits. For example, the Grasberg deposit in Papua has the world's largest gold reserves and the third-largest copper reserves (Sillitoe, 1994). Coal mining in Indonesia also has had a long history beginning with the initial production in 1849 in the Mahakam coal field near Pengaron, East Kalimantan; in 1891 in the Ombilin area, Sumatra, (van Leeuwen, 1994); and in South Sumatra in 1919 at the Bukit Asam mine (Soehandojo, 1989). Total production from deposits in Sumatra and Kalimantan, from the 19thth century to World War II, amounted to 40 million metric tons (Mt). After World War II, production declined due to various factors including politics and a boom in the world-wide oil economy. Active exploration and increased mining began again in the 1980's mainly through a change in Indonesian government policy of collaboration with foreign companies and the global oil crises (Prijono, 1989). This recent coal revival (van Leeuwen, 1994) has lead Indonesia to become the largest exporter of thermal (steam) coal and the second largest combined thermal and metallurgical (coking) coal exporter in the world market (Fairhead and others, 2006). The exported coal is desirable as it is low sulfur

  2. Effects of α-Al2 O3 and SiO2 composite micropowders on properties of self-flowing andalusite castables%α-Al2O3微粉和SiO2微粉复合引入对红柱石质自流浇注料性能的影响

    Institute of Scientific and Technical Information of China (English)

    闫光辉; 刘百宽; 尹洪峰; 李君霞; 王文学

    2014-01-01

    采用特级高铝矾土熟料、红柱石、SiO2微粉及α-Al2 O3微粉为主要原料,以Secar71水泥为结合剂,固定骨料与细粉质量比为6535,且固定粉料中SiO2微粉与α-Al2 O3微粉的总加入量(w)为8%,研究了仅改变两种微粉的加入比例(α-Al2O3微粉的加入量(w)分别为8%、6%、4%、2%、0,SiO2微粉相应为0、2%、4%、6%、8%)对试样的流动性、高温强度、物相组成和显微结构的影响。结果表明:当α-Al2 O3微粉、SiO2微粉加入量(w)各为4%时,其流动性最佳,此时体系在高温下生成了大量的一次莫来石相,针状莫来石晶体穿插在刚玉骨架之间,使材料的常温抗折强度以及抗热震性最优。%The specimens were prepared using special grade bauxite clinker,andalusite,SiO2 micropowder and α-Al2O3 micropowder as main starting materials and Secar71 cement as binder.The mass ratio of ag-gregate to fines was 65 35 and the total addition of SiO2 micropowder and α-Al2 O3 micropowder was fixed at 8% (in mass,the same hereinafter),addition of α-Al2 O3 micropowder was 8%,6%,4%,2% and 0,re-spectively.Effects of adjusting additions of the two micropowders on the flowability,hot strength,phase composition and microstructure were researched.The results show that:when the additions of SiO2 mi-cropowder and α-Al2 O3 micropowder are both 4%,the specimen performs the best flowability;a lot of nee-dle like mullite crystals form at high temperatures,crossing into the corundum skeleton,endowing the mate-rials with the optimal cold modulus of rupture and thermal shock resistance.

  3. Mine Geological Environment Impact Assessment Based on Fuzzy Comprehensive Evaluation and GIS Technology%基于模糊综合评判和GIS技术的矿山地质环境影响评价

    Institute of Scientific and Technical Information of China (English)

    陈建平; 范立民; 李成; 宁建民

    2014-01-01

    蒲白矿产资源集中开采区分布于渭北黑腰带地区的蒲城和白水县,煤炭、石灰岩、铝土矿和粘土等多种矿产的持续开发,产生了各类的矿山地质环境问题,其中煤矿采空区塌陷及裂缝最为突出。选取了地形相对高差、岩土体特征、开采方式、有效深厚比、采空区面积比、矿山地质灾害发育密度、地下水位、压占破坏土地资源等11个指标作为评价因子,构建了矿山地质环境影响评价指标体系。采用模糊综合评判法对研究区矿山地质环境影响进行评价,并结合GIS空间分析技术划分为矿山地质环境影响严重区12个,较严重区4个,较轻区2个。评价结果与实际调查情况较为相近,较客观的反映了采矿活动对矿山地质环境的影响,并结合区内实际提出了矿山地质环境恢复治理措施建议,为矿山地质环境保护与恢复治理提供了依据。%The Pucheng-Baishui mineral resources concentrated exploitation area is spread over Pucheng and Baishui counties in so-called“black-belt north of Weihe River”, the unremitting exploitation of coal, limestone, bauxite and clay has triggered various mine geological environment problems, most of all are the coalmine gob area subsidence and ground fissures. Using 11 indices including top-ographic relative elevation, rock and soil characteristics, mining method, effective ratio of mining depth and working thickness, gob ar-ea ratio, mine geological hazard development density, groundwater level, and land resources occupation and destruction as assessment factors have built a mine geological environment impact assessment index system. Using fuzzy comprehensive evaluation method car-ried out study area mine geological environment impact assessment, combined with GIS spatial analysis technology marked off 12 seri-ously impacted areas, 4 rather seriously impacted areas and 2 rather light impacted areas. The results from

  4. 和谐型大功率内燃机车高摩合成闸瓦的研制%Development of Composite Brake Shoes with High Friction Coefficient for High Power Diesel Locomotive (HXN)

    Institute of Scientific and Technical Information of China (English)

    裴顶峰; 张国文; 党佳; 贺春江

    2012-01-01

    Nitrile butadiene rubber modified phenolic resin was used as adhesive. Graphite, bauxite, potash feldspar powder, reduced ferrous powder and precipitated barium sulfate were used as filler. Steel fiber and sepiolite fiber were used as reinforcing fibers. The friction material of composite brake shoe with high friction coefficient was constituted by the blend of the above materials. Composite brake shoe with high friction coefficient for high power diesel locomotive was developed through optimizing technology and formula by trial and error. Test results show that all the physical, mechanical, braking, friction and wear properties of the developed composite brake shoe with high friction coefficient meet the technical requirements of high power diesel locomotive (HXN). The impact strength and compression modulus reaches 3. 8 kJ ? M-2 and 460 Mpa respectively. Tests of 1 : 1 Train braking dynamic test stand also show that, at the speed of 120 km ? H-1, the braking distance of the loaded car, the maximum temperature of wheel tread and abrasion loss is 817 m, 215 °C and 0. 87 cm3 ? MJ-1 respectively, which can fully meet the operating requirements of emergency braking distance less than 1100 m, the maximum temperature of wheel tread less than 400 t and the braking abrasion loss of loaded car less than 1. 5 cm3 ? MJ-1 at the speed of 120 km ? H-1. The compressive properties of composite brake shoes with high friction coefficient have reached the level of the same type foreign products.%以丁腈橡胶改性酚醛树脂为黏合剂,石墨、铝矾土、钾长石粉、还原铁粉和沉淀硫酸钡等为填料,钢纤维和海泡石纤维为增强纤维,混合构成了高摩合成闸瓦的摩擦材料;通过反复实验,优化配方及工艺,研制出适合我国和谐型大功率内燃机车运用需求的高摩合成闸瓦.测试结果显示:研制的高摩合成闸瓦的各项物理力学性能及制动摩擦磨损性能符合和谐型大功率

  5. Adubação da cana de açúcar. I - Adubação fosfatada em solo massapê-salmourao Phosphate fertilizers for sugar cane

    Directory of Open Access Journals (Sweden)

    R. Alvarez

    1957-01-01

    difference in the cane yields obtained with the use of superphosphate, degelatinated and steamed bone meal, "serranafosfato", "hiperfosfato", Argelian phosphate, and a local rock phosphate (Morro do Serrote. Superphosphate and the two types of bone meal were statistically better than a type of phosphorated bauxite, but there was no difference between this and the remaining treatments. b In "massapê-salmourão" soils of low acidity there was no statistical difference between the applications of phosphorus as superphosphate, degelatinated bone meal, "fertifós", and "hiperfosfato"; all these treatments were better than rock phosphate (Morro do Serrote.

  6. Guyana.

    Science.gov (United States)

    1985-01-01

    dominate the economic system, and 51% of the population is employed in the public sector; however, there are also cooperative and private sector enterprises. 33.8% of the work force is engaged in agriculture, 44.5% in industry and commerce, and 21.7% in services. The gross national product (GNP) was US$419 million (1983), the annual economic growth rate was 10.1% (1982-3), and per capita income was US$457 (1983). Agriculture accounts for 26% of the gross domestic product (GDP), and major agricultural products are sugar and rice. Sugar processing and marketing is handled by a government owned company. Industry, primarily the mining and processing of bauxite and aluminum, accounts for 27% of the GDP. In 1983 exports totated US$193.3 million, and exports amounted US$243 million. During the last several years, the economic situation deterioritated. Productivity is declining, equipment and facilities are outdated, and many skilled workers are emigrating. A number of economic reforms were adopted, but recovery depends on the ability of the government to reach a standby facility agreement with teh International Monetary Fund. Guyana maintains ties with both communist and capitalists countries and is engaged in a major territorial dispute with Venezuela. Since 1966, the US provided Guyana with US$415 million in unilateral and bilateral aid.

  7. Experiment on the combined extraction of iron and alumina from red mud%从赤泥中联合提取铁和氧化铝试验

    Institute of Scientific and Technical Information of China (English)

    高建军; 齐渊洪; 居殿春; 程相利; 郭玉华

    2015-01-01

    赤泥是从铝土矿中浸出氧化铝后产生的固态废渣,含有一定量的铁、氧化铝以及其他有价金属元素。为了综合回收赤泥中铁和氧化铝,开发了赤泥配碳制备成含碳球团,含碳球团直接还原-熔分生产金属铁,熔渣自粉化浸出氧化铝的方法。试验研究了不同工艺参数对赤泥中铁和氧化铝提取结果的影响,得到的最佳工艺条件为:碳氧比为1.8,还原温度为1250℃,还原时间为60 min,熔分温度为1500℃,熔分时间为20 min,熔渣冷却速度小于20℃/min,钙铝比为1.6。在最佳工艺参数下,得到的生铁磷、硫质量分数分别为0.047%和0.017%,熔渣中w(FeO)为1.26%,熔渣自粉化完全,自粉化渣中Al2O3浸出率可以达到86.65%。%Red mud is the solid waste residue generated during alumina production from bauxite,which contains consid-erable amount of alumina,ferric oxide and other valuable metals. In order to recovery alumina and iron from red mud, the process of pig iron produced by direct reduction-smelting of carbon-containing red mud pellets,and alumina leaching from self-disintegrating slag was developed. The effects of different process parameters on extraction of iron and alumina from red mud were researched. The optimum reaction parameters were obtained as the following:the ratio of carbon to oxygen is 1.8,the time of direct reduction at 1 250℃ is 60 min,the time of smelting at 1 500℃is 20 min,slag cooling rate must be less than 20℃/min,the ratio of calcium oxide to alumina is 1.6. With these optimum parameters,the phos-phorus and sulfur content in the pig iron were 0.047%and 0.017%respectively,the ferrous oxide content in the slag was 1.26%,the slag can disintegrate completely,and the alumina leaching ratio can reach 86.65%.

  8. Discovery of the superlarge gallium ore deposit in Jungar, Inner Mongolia, North China

    Institute of Scientific and Technical Information of China (English)

    DAI Shifeng; REN Deyi; LI Shengsheng

    2006-01-01

    Mineralogy and geochemistry of No.6 Coal from the Heidaigou Mine of the Jungar Coalfield of North China were studied using instrumental neutron activation analysis, inductively coupled-plasma mass spectroscopy, X-ray fluorescence spectrometry, and scanning electron microscope equipped with an energy-dispersive X-ray spectrometer. The results show that gallium concentration is as high as 44.8 μg·g-1 in the whole coal-channel sample, and varies from 30.1 μg·g-1 to 76.0 μg·g-1 (mean 51.9 μg·g-1) in the main minable benches of No.6 Coal. Such high concentration of Ga in the coal is far higher than the industrial grade (30 μg·g-1). The thickness of the main minable benches accounts for 81.9% of the whole coal bed. The laboratory high-temperature ashes (550℃) of the main minable coal benches also contain a high concentration of Ga, varying from 62.2 μg·g-1 to 178 μg·gμ1, with an average of 89.2 μg·g-1. The boehmite significantly enriched in No.6 Coal is the main carrier of the high Ga in the coal. Average concentration of Ga in boehmite is 0.09%. The average content of boehmite is 6.1% in the whole coal and 7.5% in the main minable benches. Boehmite is derived from the bauxite in the weathered crust of the underlying Benxi Formation in the north of the basin during the peat accumulation. The colloidal idrargillite had been shortly transported from the weathered crust to the peat mire, and owing to the compaction of the overlying strata during the peat accumulation and early diagenesis, the idrargillite colloid had begun to be dehydrated, leading to boehmite formation. A preliminary estimation showed that the ensured and prospected reserves of Ga in No.6 Coal are up to 6.3×104t and 8.57×105t, indicating a superlarge gallium ore deposit. The particular paleogeography of the Jungar Coalfield and the peculiar carrier of Ga in coal suggest that this Ga ore deposit is unique in the world. Rare earth elements are also enriched in coal and laboratory ashes

  9. Numerical research on feed mode of flotation column embedded with fast flotation unit based on Fluent%基于Fluent的快浮嵌入式浮选柱给料方式数值研究

    Institute of Scientific and Technical Information of China (English)

    张宁宁; 周长春; 闫小康

    2016-01-01

    基于微细粒铝土矿浮选的速度快、泡沫量大等特点,提出在旋流−静态微泡浮选柱上部嵌入快速浮选单元。为了研究嵌入式快浮单元下的给料方式对浮选柱内部流场的影响,利用计算流体力学Fluent软件对传统工业给料以及2种快浮单元给料结构下的浮选柱内部流场进行数值模拟。研究结果表明:3种给料方式下的柱体内流线虽有差异,但均能满足浮选柱对物料分选的基本要求;对于3种不同的给料方式,浮选柱旋流段的旋涡强度基本相同,在同一径向位置上切向速度的最大差值在0.1 m/s以内,说明给料方式对浮选柱内部流场影响较小;与其他2种给料方式相比,快浮单元环形给料下的浮选柱入料段湍流强度低,湍动能主要集中在0~0.05 m2/s2,柱分选段轴向速度主要集中在−0.15~0.15 m/s,轴向速度沿径向分布较其他2种均匀,对矿物的分选以及二次富集更有利。%Based on characteristics of fast speed and large amount of foam in flotation of micro-fine bauxite, a fast flotation unit embedded in the cyclone-static micro bubble flotation column was proposed. In order to study the effects of feeding methods on flow field in flotation column embedded with fast floating units, Fluent, a computational fluid dynamics software, was used to simulate the internal flow field structure of flotation column with different feeding forms, including a traditional industry feeding form as well as two feeding forms under fast floating unit. The results show that all the forms could meet the basic requirements of flotation column for sorting materials, in spite of the difference of flow lines in the column. For three feeding methods, the vortex intensities of swirl segment in column are basically the same, and the maximum difference among the tangential velocities at the same radial position is within 0.1 m/s, which illustrates that feeding methods have little

  10. The geology of aluminium phosphates and sulphates of the alunite group minerals: a review

    Science.gov (United States)

    Dill, Harald G.

    2001-03-01

    Aluminium phosphates and sulphates of the alunite supergroup (APS minerals) occur in a wide range of environments of formation covering the metamorphic, igneous and sedimentary realms. Supergene processes, including mineral dressing and dumping when sulphide ores are mined, as well as hypogene alteration are also responsible for the precipitation of APS minerals. In these environments, complex solid solution series (s.s.s.) can form. The general formula of these alunite minerals is AB 3 (XO 4) 2(OH) 6, where A is a large cation (Na, U, K, Ag, NH 4, Pb, Ca, Ba, Sr, REE). B sites are occupied by cations of the elements Al, Fe, Cu and Zn. In nature, the anion (XO 4) x- is dominated by P and S. Mineral dressing and identification of APS minerals often needs a combination of highly sophisticated measures including Atterberg settling methods, XRD, DTA, TGA, TEM-EDX, SEM, EMPA and XRF. In sedimentary rocks APS minerals occur in various rocks and environments of deposition: calcareous, phosphorite-bearing, argillaceous-carbonaceous, arenaceous, coal-bearing environments, in soils and paleosols, in saprolite (bauxites, laterites) and in calcareous-argillaceous sequences hosting Carlin-type SHDG deposits. In igneous rocks, APS minerals may be encountered mainly in acidic through intermediate pyroclastic, volcanic and subvolcanic rocks. They occur in barren volcanic rocks and porphyry-type intrusions that have sparked epithermal Au-Ag-base metal deposits, Au-Sb mineralization, APS-bearing argillite and alunite deposits in their immediate surroundings. Granitic and pegmatitic rocks are rarely host of supergene APS mineralization. During low-grade stage regional metamorphism, peraluminous parent rocks originating from a sedimentary or igneous protolith may also give rise to APS mineralization. Peraluminous parent rocks enriched in S and/or P are a prerequisite for the formation of APS minerals that are stable up to a temperature of 400°C at moderately high fluid pressure of up

  11. 中国铝的社会蓄积量及折旧再生指数分析%Analysis of Al-Contents in Social Stock and the Regeneration Index of Depreciated Aluminum Products in China

    Institute of Scientific and Technical Information of China (English)

    岳强; 杜岩; 王鹤鸣

    2015-01-01

    我国近些年来原铝产量和消费量快速增长,铝土矿资源严重不足,在很大程度上依赖于进口.随着铝社会蓄积量的增大,废铝资源将越来越多,并在铝工业中发挥更大的作用.通过对我国铝的社会蓄积量及其平均年龄、回收率、折旧再生指数等进行分析,得到以下结果:1990年~2010年铝的社会蓄积量从723万 t 增长到10355万 t;2010年铝制品的平均年龄约为4.3年,折旧再生指数和铝的社会蓄积量回收率分别为0.0747 t /t和1.17%.基于未来铝消费的3种情景进行了分析,在情景3下:预计我国铝的社会蓄积量在2035年达到最大值6亿 t,2055年稳定在5.7亿 t;铝制品平均年龄在2040年达到最大值(7.13年),同年折旧再生指数达到最大值(0.79 t/t),铝的社会蓄积量回收率也达到最大值(5.05%).研究结果将为铝工业相关政策的制定提供一定的参考.%Aluminum production and consumption have increased quickly in China in recent years,while bauxite is in severely shortage and has to been imported from overseas.With the increment of aluminum social stock,the old scrap will become larger and play a greater role in aluminum industry.The social stock of aluminum,average age,old scrap recovery rate and regeneration index were analyzed.The results showed that social stock of aluminum in China increased from 7.23 million tons to 103.55 million tons in the period 1990 ~2010.The average age of aluminum products in social stock was about 4.3 years,and the regeneration index of depreciated aluminum products and recovery rate of aluminum social stock were 0.074 7 t /t and 1.17 percent,respectively,in 2010.Three scenarios analysis for different aluminum consumption conditions were carried out,and under the third scenario:the amount of aluminum social stock will reach 6 hundred million tons in 2035 and keep constant at 5.7 hundred million tons in 2055. In the year 2040,the average age of aluminum products in social

  12. Geochemistry of Selected Coal Samples from Sumatra, Kalimantan, Sulawesi, and Papua, Indonesia

    Science.gov (United States)

    Belkin, Harvey E.; Tewalt, Susan J.

    2007-01-01

    Introduction Indonesia is an archipelago of more than 17,000 islands that stretches astride the equator for about 5,200 km in southeast Asia (figure 1) and includes major Cenozoic volcano-plutonic arcs, active volcanoes, and various related onshore and offshore basins. These magmatic arcs have extensive Cu and Au mineralization that has generated much exploration and mining in the last 50 years. Although Au and Ag have been mined in Indonesia for over 1000 years (van Leeuwen, 1994), it was not until the middle of the nineteenth century that the Dutch explored and developed major Sn and minor Au, Ag, Ni, bauxite, and coal resources. The metallogeny of Indonesia includes Au-rich porphyry Cu, porphyry Mo, skarn Cu-Au, sedimentary-rock hosted Au, epithermal Au, laterite Ni, and diamond deposits. For example, the Grasberg deposit in Papua has the world's largest gold reserves and the third-largest copper reserves (Sillitoe, 1994). Coal mining in Indonesia also has had a long history beginning with the initial production in 1849 in the Mahakam coal field near Pengaron, East Kalimantan; in 1891 in the Ombilin area, Sumatra, (van Leeuwen, 1994); and in South Sumatra in 1919 at the Bukit Asam mine (Soehandojo, 1989). Total production from deposits in Sumatra and Kalimantan, from the 19thth century to World War II, amounted to 40 million metric tons (Mt). After World War II, production declined due to various factors including politics and a boom in the world-wide oil economy. Active exploration and increased mining began again in the 1980's mainly through a change in Indonesian government policy of collaboration with foreign companies and the global oil crises (Prijono, 1989). This recent coal revival (van Leeuwen, 1994) has lead Indonesia to become the largest exporter of thermal (steam) coal and the second largest combined thermal and metallurgical (coking) coal exporter in the world market (Fairhead and others, 2006). The exported coal is desirable as it is low sulfur

  13. The submarine river of Port Miou (France), A karstic system inherited from the Messinian deep stage

    Science.gov (United States)

    Cavalera, T.; Gilli, E.

    2009-04-01

    , upstream of the dam and at the end of the cave. The presence of heavy metals in the sediments of the Port Miou gallery is explained as resulting from the suction of residues of bauxite treatments, rejected in the nearby Cassidaigne deep-sea canyon at a depth of 300 m bsl. This residual product locally called "red mud" is very rich in titanium. The saline contamination of Port Miou could be carried out by a seawater inflow through a deep karstic conduit connected to the canyon of Cassidaigne. A long term monitoring of the springs, indicates that the system is contaminated by a permanent sweater inflow close to 500 l.s-1. A laboratory model has been realized that simulates perfectly the functioning.

  14. A critique of Phanerozoic climatic models involving changes in the CO 2 content of the atmosphere

    Science.gov (United States)

    Boucot, A. J.; Gray, Jane

    2001-12-01

    Critical consideration of varied Phanerozoic climatic models, and comparison of them against Phanerozoic global climatic gradients revealed by a compilation of Cambrian through Miocene climatically sensitive sediments (evaporites, coals, tillites, lateritic soils, bauxites, calcretes, etc.) suggests that the previously postulated climatic models do not satisfactorily account for the geological information. Nor do many climatic conclusions based on botanical data stand up very well when examined critically. Although this account does not deal directly with global biogeographic information, another powerful source of climatic information, we have tried to incorporate such data into our thinking wherever possible, particularly in the earlier Paleozoic. In view of the excellent correlation between CO 2 present in Antarctic ice cores, going back some hundreds of thousands of years, and global climatic gradient, one wonders whether or not the commonly postulated Phanerozoic connection between atmospheric CO 2 and global climatic gradient is more coincidence than cause and effect. Many models have been proposed that attempt to determine atmospheric composition and global temperature through geological time, particularly for the Phanerozoic or significant portions of it. Many models assume a positive correlation between atmospheric CO 2 and surface temperature, thus viewing changes in atmospheric CO 2 as playing the critical role in regulating climate/temperature, but none agree on the levels of atmospheric CO 2 through time. Prior to the relatively recent interval of time in which atmospheric CO 2 is directly measurable, a variety of biological and geological proxies have been proposed to correlate with atmospheric CO 2 level or with pCO 2/temperature. Atmospheric models may be constructed for the Pre-Cenozoic but the difficulties of assessing variables in their construction are many and complex. None of the modelers have gathered enough biological and geological data to

  15. Heuristic economic assessment of the Afghanistan construction materials sector: cement and dimension stone production

    Science.gov (United States)

    Mossotti, Victor G.

    2014-01-01

    Over the past decade, the U.S. Government has invested more than $106 billion for physical, societal, and governmental reconstruction assistance to Afghanistan (Special Inspector General for Afghanistan Reconstruction, 2012a). This funding, along with private investment, has stimulated a growing demand for particular industrial minerals and construction materials. In support of this effort, the U.S. Geological Survey released a preliminary mineral assessment in 2007 on selected Afghan nonfuel minerals (Peters and others, 2007). More recently, the 2007 mineral assessment was updated with the inclusion of a more extensive array of Afghan nonfuel minerals (Peters and others, 2011). As a follow-up on the 2011 assessment, this report provides an analysis of the current use and prospects of the following Afghan industrial minerals required to manufacture construction materials: clays of various types, bauxite, gypsum, cement-grade limestone, aggregate (sand and gravel), and dimension stone (sandstone, quartzite, granite, slate, limestone, travertine, marble). The intention of this paper is to assess the: Use of Afghan industrial minerals to manufacture construction materials, Prospects for growth in domestic construction materials production sectors, Factors controlling the competitiveness of domestic production relative to foreign imports of construction materials, and Feasibility of using natural gas as the prime source of thermal energy and for generating electrical energy for cement production. The discussion here is based on classical principles of supply and demand. Imbedded in these principles is an understanding that the attributes of supply and demand are highly variable. For construction materials, demand for a given product may depend on seasons of the year, location of construction sites, product delivery time, political factors, governmental regulations, cultural issues, price, and how essential a given product might be to the buyer. Moreover, failure on the

  16. Modes, tempo and spatial variability of Cenozoic cratonic denudation: morphoclimatic constraints from West Africa

    Science.gov (United States)

    Beauvais, Anicet; Chardon, Dominique

    2010-05-01

    After the onset of Gondwana break-up in the Early Mesozoic, the emerged part of the African plate underwent long Greenhouse effect climatic periods and epeirogeny. The last Greenhouse effect period in the Early Cenozoic and the alternation of wet and dry climatic periods since the Eocene enhanced episodes of rock chemical weathering and laterite production, forming bauxites and ferricretes, interrupted by drier periods of dominantly mechanical denudation, shaping glacis [1]. In Sub-Saharan West Africa, this evolution resulted in pulsate and essentially climatically-forced denudation that has shaped an ubiquitous sequence of five stepped lateritic paleosurfaces that synchronously developed over Cenozoic times. The modes, timing and spatial variability of continental denudation of the region are investigated by combining geomorphologic and geochronological data sets. The geomorphologic data set comprises the altitudinal distribution of the lateritic paleosurfaces relicts and their differential elevation from 42 locations in Sub-Saharan West Africa where the sequence (or part of it) has been documented. The geochronological data set consists in the age ranges of each paleosurface tackled by radiometric 39Ar-40Ar dating of the neoformed oxy-hydroxides (i.e., cryptomelane, K1-2Mn8O16, nH2O, [4]) carried by their laterites at the Tambao reference site, Burkina Faso [1, 3]. Five groups of 39Ar-40Ar ages, ~ 59 - 45 Ma, ~ 29 - 24 Ma, ~ 18 - 11.5 Ma, ~ 7.2 - 5.8 Ma, and ~ 3.4 - 2.9 Ma, characterize periods of chemical weathering whereas the time laps between these groups of ages correspond to episodes of mechanical denudation that reflect physical shaping of the paleosurfaces. For the last 45 Ma, the denudation rate estimates (3 to 8 m Ma-1) are comparable with those derived on shorter time scale (103 to 106 y.) in the same region by the cosmogenic radionuclide method [2]. Combined with the geomorphologic data set, these age ranges allow the visualization of the regional

  17. Quantitative physical and chemical variables used to assess erosion and fertility loss in tropical Dominican and Haitian soils

    Science.gov (United States)

    Pastor, J.; Alexis, S.; Vizcayno, C.; Hernández, A. J.

    2009-04-01

    The Pedernales province (Dominican Republic) has the main part of the only Biosphere Reserve in that Caribbean Island, including the Bahoruco and Jaragua National Parks. In these Parks is possible to find almost the totality of tropical forest ecosystems (evergreen rain forest, latifoliated forest, dry forest and mangrove forest on mainland), as well as the most frequent soil uses in the Dominican country. The consulted bibliography about the soils is very scarce and it does not give any information relating to this natural resource, which is basic for a sustainable development management in this territory. When Christopher Columbus reached the island, its plant cover constituted 95% of the land. This was largely because the limited, rudimentary tools used by the Indians to exploit the soil, allowed them to maintain a well-balanced ecological system. The initial type of agriculture practised by the indigenous inhabitants was scarcely destructive and based on vegetatively reproducing crops propagated through cuttings, but later forest burning was an especially significant management practice aimed at releasing nutrients into the soil, in an environment in which under natural conditions, particularly those of the rainforest, these were mostly locked within plant structures. The colonial system, on the contrary, brought with it more elaborate methods and utensils enabling them to cultivate cereals (somewhat unknown to the native Indians) and to rear livestock (cows, goats) yet contributed to the growth of deforestation. Agricultural activities were not confined to the plains; even the virgin woods of the mountains were exploited. The monocrops grown across vast expanses rapidly rid the soil of its productive capacity. Cutting down and burning forest for agricultural uses, and also industrial exploitation of bauxite and limestone produced also important alterations in the soil processes. Agricultural activities were not confined to the plains; even the virgin woods of

  18. Ação sonoquímica e influência das condições de tratamento térmico na preparação de cimentos do sistema binário CaO-Al2O3 Sonochemical action and the influence of heat treatment conditions on the preparation of cements of the CaO-Al2O3 binary system

    Directory of Open Access Journals (Sweden)

    R. R Lourenço

    2010-03-01

    lime and bauxite or alumina is melted or sintered. High temperatures and energy consumption is an inconvenience associated to this type of synthesis. In the sonochemical process, the initial reagents, calcia and alumina, are put in an aqueous suspension under the action an ultrasonic bath during some time. After that, the material is heat treated, after the evaporation of water. Ultrasonic waves can induce changes in the surface morphology of the particles, including size reduction of them. Consequently, the reagent particles become more reactive and this facilitates the final synthesis of the calcium aluminates during the heat treatment. The action of ultrasonic waves and the influence of thermal treatment conditions were studied on two initials molar compositions calcia:alumina of 1:1 and 1:2. Temperatures of 1000, 1200 and 1300 ºC for 1 and 6 h were employed. SEM and X-ray diffraction were used to characterize the obtained materials and the phases were semi-quantified through Rietveld method. In addition, mechanical strength of the products was evaluated through splitting tensile tests. Pastes consisting of cement, alumina and water were prepared using the calcium aluminates prepared through the sonochemical process and commercial cement as reference.

  19. Síntese e caracterização de hidróxidos duplos a partir da lama vermelha Synthesis and characterization of layered double hydroxides from red mud

    Directory of Open Access Journals (Sweden)

    M. V. P. O. Cunha

    2011-03-01

    testar esses materiais como adsorventes de metais pesados.Bauxite refinery residues, commonly known as "red mud", have been shown to be capable of binding trace metals such as copper, cadmium, zinc, chromium, nickel and lead under suitable conditions. Neutralization of red mud is necessary because red muds are typically highly caustic, with a reaction pH of about 13. Much research has been carried out on utilization of red mud because it contains a lot of valuable components. Although utilization of the red mud as building material and as an absorbent is attractive because the red mud is used in bulk, nothing can be done without discarding valuable components such as titanium, zirconium and the main iron. Hydrotalcite-synthesis connected with recycling of alkali-solution is a prospective way for effective use of the solution under the strong demand for the environmental protection in the world. The hydrotalcite-like compounds, precipitated during neutralization, also remove oxy-anions of transition metals through a combination of intercalation and adsorption of the anionic species on the external surfaces. Layered double hydroxides (LDHs have been investigated for many years as host materials for a range of anion exchange intercalation reactions. The lamellar structure of LDHs can be used for the controlled addition or removal of a variety of species, both organic and inorganic. This is achieved through their ability to adjust the separation of the hydroxide layers, and the reactivity of the interlayer region. The resultant material adsorbs anions when placed in solution and reverts to the hydrotalcite structure. Significant advances have been made recently on the characterization of these materials, including structural studies on the mechanism of intercalation. The aim of this work was the synthesis and characterizations of LDHs from red mud that will be tested as adsorbent material for heavy metals.

  20. Dinâmica da estrutura diamétrica da regeneração natural de espécies arbóreas e arbustivas no sub-bosque de povoamento puro de Mimosa scabrella Bentham, em área minerada, em Poços de Caldas, MG Diametric struture dynamics for tree and shrub natural regeneration understory within pure stands of Mimosa scabrella Bentham planted on a mined-out site at Poços de Caldas, Minas Gerais state

    Directory of Open Access Journals (Sweden)

    Mauro Eloi Nappo

    2005-02-01

    interno da sucessão.Retiro-Branco mine, a property of Companhia Geral de Minas, subsidiary of ALCOA Alumínio S.A., underwent bauxite extraction from 1978 to 1981. In 1982/1983 as part of its mine rehabilitation strategy, herbaceous species were hydroseeded and tree seedlings of Mimosa scabrella Bentham planted in the mining site. In 1997, 19 sample plots (50m² were established in this area for the initial characterization of the natural regeneration process. In 2000, a second inventory was performed in the same plots to characterize natural regeneration dynamics. The process of natural regeneration dynamics was characterized through quantitative and qualitative analyses of diameter distribution. These studies demonstrated that using continuous forest inventory with a sample plot grid is a viable tool for evaluating natural regeneration dynamics. The stratification process for natural regeneration was characterized. Pioneer and climax species are the main components of the inferior stratum and the secondary ones the main component of the superior stratum. Retiro-Branco forest was found to be undergoing intense structuring activity, characterizing initial stage of succession. Secondary species are the most dominant in classes with greatest height and diameter, being the most responsible for the superior stratum construction. Diameter distribution prediction using Markov Matrix proved to be a simple way for foreseeing both the succession process of natural regeneration and future ecological groupings of species, increasing the understanding of mechanisms that rule internal succession behavior.

  1. Dinâmica da estrutura fitossociológica da regeneração natural em sub-bosque de Mimosa scabrella Bentham em área minerada, em Poços de Caldas, MG Phytosociology structure dynamics of natural regeneration in understory of Mimosa scabrella Bentham in mined area, Poços de Caldas, Brazil

    Directory of Open Access Journals (Sweden)

    Mauro Eloi Nappo

    2004-12-01

    estratégia sucessional.As part of mine rehabilitation strategy, herbaceous species hydroseeding and Mimosa scabrella Bentham seedling planting was carried out in 1982/1983 the Retiro-Branco bauxite mine site. In 1997, 19 sample plots of 50m² were established for initial characterization of the natural regeneration process. In 2000, a second inventory was performed in those same sample plots, to characterize natural regeneration dynamics. This process was characterized by means of quantitative and qualitative analyses of floristic composition and horizontal and vertical structures. The forest succession at Retiro-Branco was found to be undergoing intense restructuring activity, characterizing initial stage of succession. The decline of Mimosa scabrella pure stands is modifying the successional order that previously occurred in this area, causing diversity in site conditions. Occupation of these sites occurs by ecological groups, pioneer species being favored in the process. Secondary species, especially Miconia sellowiana, dominate the classes with greatest height and diameter, and are the most responsible for construction of the superior stratum. Species which presented the best performance in colonization and structuring of natural regeneration at Retiro-Branco for both inventories were Miconia sellowiana, Psychotria sessilis, Leandra melastomoides, Clethra scabra, Myrsine umbellata, Miconia pepericarpa, Tibouchina candolleana, Cordia superba, Cestrum amictum, Alchornea triplinervia, Casearia sylvestris, Blepharocalyx salicifolius, Myrcia rostrata and Schinus terebinthifolius. These are indicated as promising species for rehabilitation programs of mined areas with similar conditions of sucessional strategy.

  2. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Kandahar mineral district in Afghanistan: Chapter Z in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Kandahar mineral district, which has bauxite deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420-500 nanometer, nm), green (520-600 nm), red (610-690 nm), and near-infrared (760-890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520-770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency ((c)JAXA,2006,2007,2008), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such, the DS

  3. 硫对钢材碱性腐蚀的研究综述%Review on Sulfur Corrosion of Steel in Alkaline Environment

    Institute of Scientific and Technical Information of China (English)

    杨夏琼; 陈朝轶; 李军旗; 权变利

    2015-01-01

    Sulfur corrosion of steel is a universal problem in petroleum chemistry industry, paper and pulp industry, and alu-mina production industry. It has been proved by studies that the corrosion life of 3. 5 mm thick CT20 carbon steel was only 6 hours when it was in sodium hydroxide solution with 5 g/L S2-, and the corrosion rate of 16Mn steel was as high as 151. 21 mm/y when it was in sodium aluminate solution with 5 g/L S2-. The current research status of 4 forms of sulfur ( S2-, S2 O2-3 , SO2-3 , SO2-4 ) cor-rosion of steel in alkaline solution was reviewed in this paper, and the research progress of S2-corrosion of steel in alkali conditions was discussed particularly. Bayer process is the common method of alumina production with high-sulfur bauxite, during the pro-gress, sulfur is transformed into sodium aluminate solution in the forms of S2-, S2 O2-3 and smaller amounts of SO2-3 , SO2-4 , leading to serious corrosion of the production equipment. At present, sulfur corrosion of steel in sodium aluminate solution is seldom repor-ted, especially the coupled corrosive effects of different forms sulfur on equipment material when they coexist in sodium aluminate solution:the corrosion rate of 16Mn steel was dramatically reduced to 8. 66 mm/a from 151. 21 mm/a when 5 g/L S2 O2-3 was added into sodium aluminate solution with 5 g/L S2-. Finally, study on the mechanism of coupled corrosion was prospected.%硫对钢材的腐蚀是石油化工行业、造纸工业及氧化铝生产行业面临的一个普遍问题。研究表明,纯氢氧化钠溶液中S2-质量浓度达到5 g/L时,3.5 mm厚的CT20碳钢的腐蚀寿命只有6 h,且16Mn钢在含有5 g/L的S2-的铝酸钠溶液中腐蚀速率高达151.21 mm/a。综述了碱性条件下S2-,S2 O2-3,SO2-3和SO2-4等4种形态的硫对钢材腐蚀的研究现状,重点阐述了苛碱条件下S2-对钢材腐蚀的研究进展。拜耳法是高硫铝土矿生产氧化铝的常用方法,在生产过程中,硫以S2-,S2 O2-3

  4. Heuristic economic assessment of the Afghanistan construction materials sector: cement and dimension stone production

    Science.gov (United States)

    Mossotti, Victor G.

    2014-01-01

    Over the past decade, the U.S. Government has invested more than $106 billion for physical, societal, and governmental reconstruction assistance to Afghanistan (Special Inspector General for Afghanistan Reconstruction, 2012a). This funding, along with private investment, has stimulated a growing demand for particular industrial minerals and construction materials. In support of this effort, the U.S. Geological Survey released a preliminary mineral assessment in 2007 on selected Afghan nonfuel minerals (Peters and others, 2007). More recently, the 2007 mineral assessment was updated with the inclusion of a more extensive array of Afghan nonfuel minerals (Peters and others, 2011). As a follow-up on the 2011 assessment, this report provides an analysis of the current use and prospects of the following Afghan industrial minerals required to manufacture construction materials: clays of various types, bauxite, gypsum, cement-grade limestone, aggregate (sand and gravel), and dimension stone (sandstone, quartzite, granite, slate, limestone, travertine, marble). The intention of this paper is to assess the: Use of Afghan industrial minerals to manufacture construction materials, Prospects for growth in domestic construction materials production sectors, Factors controlling the competitiveness of domestic production relative to foreign imports of construction materials, and Feasibility of using natural gas as the prime source of thermal energy and for generating electrical energy for cement production. The discussion here is based on classical principles of supply and demand. Imbedded in these principles is an understanding that the attributes of supply and demand are highly variable. For construction materials, demand for a given product may depend on seasons of the year, location of construction sites, product delivery time, political factors, governmental regulations, cultural issues, price, and how essential a given product might be to the buyer. Moreover, failure on the

  5. Construction Site Foundation Stability Assessment in an Old Gob Subsidence Area in Tangshan, Hebei%河北唐山某老采煤沉陷区建设场地地基稳定性评价

    Institute of Scientific and Technical Information of China (English)

    张立才; 刘燕龙

    2013-01-01

    There were mining activities mainly coal mining in the study area and formed extensive gob subsidence. For the purpose of intensive use of land and hazard prevention and mitigation, along the technical route of combined theoretical analysis, quantitative com-putation and site observation, Based on the“three (caving, fracture and bending) zones”theory, qualitatively and quantitatively as-sessed extent of gob area impacts spread to surface and surface displacement range, and using stress analysis method carried out site stability analysis. The result has shown:most gob areas in the area are basically stable and in a residual deformation stage;surface is in a relatively stable condition;residual deformation is within structure acceptable range. Not fully collapsed compaction area is existed in shallow gob area, under the impacts from surface structural load, earthquake and groundwater, still has possibility of secondary activa-tion. The age of old gob area in central south part is more than 5 years, thus the activation process is rather stable and long-range, gen-erally less impact on surface and slow subsiding, its uneven settlement is limited. In central south part had a Kailuan bauxite mine origi-nally, its mining method was tunnel mining, rather shallow occurrence, under the surface structural load, easy to collapse and activated, thus rather hazardous. In allusion to different regions and activation types, put forward corresponding controlling measures, thus has cer-tain reference value in construction site foundation stability assessment.%研究区内历史上存在强烈的以采煤为主的采矿活动,形成了大规模的采空塌陷,为了集约用地和防灾减灾,运用理论分析、定量计算及现场观测相结合的技术路线,根据“三带”理论对采空区波及地表的影响程度和地表移动的范围定性定量评价,应用应力分析法对场区进行稳定性分析。结果表明:该区大部分采空区基本稳

  6. Determination of Major and Minor Components in High-Cr Red Mud by X-ray Fluorescence Spectrometry with Fusion Sample Preparation%熔融制样X射线荧光光谱法测定高铬赤泥中主次量组分

    Institute of Scientific and Technical Information of China (English)

    朱忠平; 曾精华; 王长根; 吕立超

    2014-01-01

    be analyzed by X-ray Fluorescence Spectrometry (XRF).However,a use of sodium flux and a high dilution ratio are not conducive to sodium and low content elements.In this paper,a method of XRF analysis is developed for the determination of the major and minor components (Cr,Si,Al,Fe,Mg,Ca,Na,K,S,P,Ti,Mn and V)in high-Cr red mud by fused bead preparation with Li2B4O7-LiBO2(67∶33)flux,NH4NO3 oxidizer and saturated LiBr solution parting medium.When the dilution ratio of the melting sample is lower than 24∶1 ,the lower dilution ratio,the more serious is the corrosion on the Pt-Au crucible;the RSD (n=1 0)of the sample preparation method is at a minimum when the dilution ratio is 24∶1;the longer the melting time and the higher the melting temperature,the RSD becomes lower.The optimization conditions of fused bead are obtained when the dilution ratio is 24∶1 ,the melting temperature is 1 1 00℃ and the melting time is 1 5 min.The working curve was established by chromite,bauxite,clay,iron ore standards and manual preparation standard materials.The matrix effect and spectrum line overlap interference were corrected by a fundamental parameter method and standard regression.The results are consistent with certified values and the RSD (n=10)is from 0.3% to 3.9%.Compared with domestic and foreign XRF methods for chromium-containing minerals,this method uses no sodium salt,a fuse piece,conventional sample melting temperature (1 1 00℃),low dilution ratio (24 ∶1 )for sample preparation,and the sampling precision and analysis precision are low.The problem with XRF analysis of high-Cr red mud has been solved by this method,which can be used to analyze Cr,Al, Si and Fe in roasting,concentrates and tailings and other ores processed by sodium.

  7. 泡沫胶凝法制备轻质钙长石耐火材料的工艺研究%Preparation of lightweight anorthitic refractories by foaming-gel method

    Institute of Scientific and Technical Information of China (English)

    夏光华; 谢穗; 何婵

    2011-01-01

    Lightweight anorthitic was prepared by foaming-gel method using calcined bauxite, calcined kaolin, wollastonite,protein foaming agent, gelatin, polyvinyl alcohol, silica sol, and polymeric aluminum sulfate as starting materials. The influences of protein foaming agent addition, gelatin addition, adding occasions of silica sol and polymeric aluminum sulfate as well as the silica sol addition on the foam-gel shaping were discussed,and the chemical composition, microstructure, and properties of the fired lightweight anorthitic were analyzed. The results show that: ( 1 ) when volume content of protein foaming agent in protein foaming agent-water system is 15% ,the foaming multiple of the system is the biggest; when adding 1.2 g gelatin in 100 mL protein foaming agent-water system,the subsidence rate of bubble is the lowest and its stability is the best;when spreading polymeric aluminum sulfate coagulant to sticky mud to prepare foamed mud,stirring at high speed,slowly adding silica sol in proportion of 137 mL silica sol in 1 L slurry bubble,15 min after stirring,the system begins to have the gelation ;2)the lightweight anorthite material shaping by the optimum technology and firing at 1 280 ℃ for 0.5 h,consists of anorthitic as principal crystalline phase and a small amount of corundum phase; the fired anorthite lightweight material has porous structure,and its pores are mostly closed with average size of about 200 μm and distribute uniformly; performance parameters of fired anorthite lightweight materials have achieved or even surpassed those of Germany's Jm23 brick.%以煅烧矾土、煅烧高岭土、硅灰石、蛋白质发泡剂、明胶、聚乙烯醇、硅溶胶和聚合硫酸铝为原料,采用泡沫胶凝法制备了轻质钙长石材料,主要研究了蛋白质发泡剂加入量、明胶加入量、硅溶胶和聚合硫酸铝的加入时机以及硅溶胶加入量等对泡沫胶凝成型工艺的影响,并分析了烧成后轻质钙长石材料的物相

  8. 引入 Y2 O3对刚玉-尖晶石中间包挡渣墙高温强度和抗渣性的影响%Influence of adding Y2O3 on HMOR and slag resistance of corundum-spinel tundish slag barrier

    Institute of Scientific and Technical Information of China (English)

    郭钰龙; 梁永和; 聂建华; 尹玉成

    2015-01-01

    Corundum-spinel tundish slag wall specimens were prepared using special grade bauxite,brown corundum,fused white corundum,magnesium aluminate spinel,α-Al 2 O3 micropowder,ρ-Al 2 O3 ,calcium alu-minate cement as the main raw materials,adding dispersant and other additives like steel fibre.The effect of Y2 O3 addition on hot properties and slag resistance of the specimens was studied.The results show that with Y2 O3 addition increasing,the specimens have higher hot strength and better slag resistance.When the Y2 O3 addition is 2 mass%,the specimen has the best hot strength and slag resistance.The microstructure analysis shows that at high temperatures Y2 O3 reacts with Al 2 O3 forming high melting point phase Y3 Al 5 O12 , which activates the crystal lattice and enhances the density of the specimen effectively.Y2 O3 is active and can form liquid yttrium silicate with silica at high temperatures,bonding spinel and Al 2 O3 in the material tightly,and preventing the further slag penetration.As the addition of Y2 O3 increases,abundant CA6 protec-tion layers are observed at the reaction layer and the penetration layer,restraining the further penetration of slag.Meanwhile,the formed CA6 consumes CaO in the slag,enhancing the slag viscosity and lowering the penetration ability of the slag,and thus stopped slag penetration gradually.%以特级矾土、棕刚玉、电熔白刚玉、镁铝尖晶石、α-Al2 O3微粉、ρ-Al2 O3、铝酸钙水泥为主要原料,添加分散剂和钢纤维等外加剂,研究了加入 Y2 O3对刚玉-尖晶石质中间包挡渣墙高温性能和抗渣性能的影响。结果表明:随着 Y2 O3加入量的增加,试样的高温抗折强度增大,抗渣性能变好,当加入量为2%(w)时其高温强度和抗渣性能均最优。显微结构分析表明:Y2 O3高温下与 Al2 O3反应生成 Y3 Al5 O12高熔点相,活化了晶格,有效提高试样的致密度,Y2 O3活性较大,高温下还能与材料中 SiO2反应形

  9. High sorption materials for SFL - A literature review

    Energy Technology Data Exchange (ETDEWEB)

    Krall, Lindsay [Svensk Kaernbraenslehantering AB, Stockholm (Sweden)

    2012-05-15

    passive, and the material must be suitable over a much longer period of time. Bentonite and zeolite are the most relevant cation exchangers. While bentonite may be applicable, to develop a concept around zeolite may require a substantial work and resources. Moreover, the 1999 assessment results suggest that cation exchange is not necessarily a concern due to adsorption to concrete, gravel, and bedrock. Layered double hydroxides are a class of clays that have been investigated for their anion exchange capacities, which are high at pH below neutral. Hydrous metal oxides are amphoteric, which implies that they adsorb anions at low pH and cations at high pH. The exchange capacity and the pH demarking the transition from cation to anion exchange varies by type of oxide. Zero-valent iron (ZVI) and red mud are the most complex materials, which may imply versatility. ZVI in itself is not an adsorbent, but it will corrode if utilized. The corrosion products may be capable of adsorbing anions and cations, but the specific species and adsorption capacities will change over time as corrosion continues. Hematite would be the final corrosion product. Red mud, a highly alkaline waste product of bauxite processing, and its derivations are complex in that they are comprised of a variety of minerals. These include zeolite-like minerals that may adsorb cations, amphoteric metal oxides, and LDHs when neutralized with seawater. Beyond its apparent versatility as an adsorbent, this survey also found investigations into the potential application of red mud to cement, building materials, and as an adsorbent in a shallow LLW repository. Since it is also available in large quantities and possibly less costly than ordinary Portland cement, basic studies comparing the properties of these two materials may be interesting and worthwhile. Still, further information regarding the site conditions and the disposal concept in general would be helpful in determining the most efficient adsorbent.