Surface analytical techniques applied to minerals processing

International Nuclear Information System (INIS)

Smart, R.St.C.

1991-01-01

An understanding of the chemical and physical forms of the chemically altered layers on the surfaces of base metal sulphides, particularly in the form of hydroxides, oxyhydroxides and oxides, and the changes that occur in them during minerals processing lies at the core of a complete description of flotation chemistry. This paper reviews the application of a variety of surface-sensitive techniques and methodologies applied to the study of surface layers on single minerals, mixed minerals, synthetic ores and real ores. Evidence from combined XPS/SAM/SEM studies have provided images and analyses of three forms of oxide, oxyhydroxide and hydroxide products on the surfaces of single sulphide minerals, mineral mixtures and complex sulphide ores. 4 refs., 2 tabs., 4 figs

South Africa's mineral industry

International Nuclear Information System (INIS)

1985-06-01

The main aim of the Minerals Bureau in presenting this annual review is to provide an up-to-date reference document on the current state of the mineral industry in South Africa. This includes a brief look at the production, trade, economy, resources and deposits of precious metals and minerals, energy minerals, metallic minerals, and non-metallic minerals. One article discusses the production, trade, export, deposits and economy of uranium

Microbiological metal extraction processes

International Nuclear Information System (INIS)

Torma, A.E.

1991-01-01

Application of biotechnological principles in the mineral processing, especially in hydrometallurgy, has created new opportunities and challenges for these industries. During the 1950's and 60's, the mining wastes and unused complex mineral resources have been successfully treated in bacterial assisted heap and dump leaching processes for copper and uranium. The interest in bio-leaching processes is the consequence of economic advantages associated with these techniques. For example, copper can be produced from mining wastes for about 1/3 to 1/2 of the costs of copper production by the conventional smelting process from high-grade sulfide concentrates. The economic viability of bio leaching technology lead to its world wide acceptance by the extractive industries. During 1970's this technology grew into a more structured discipline called 'bio hydrometallurgy'. Currently, bio leaching techniques are ready to be used, in addition to copper and uranium, for the extraction of cobalt, nickel, zinc, precious metals and for the desulfurization of high-sulfur content pyritic coals. As a developing technology, the microbiological leaching of the less common and rare metals has yet to reach commercial maturity. However, the research in this area is very active. In addition, in a foreseeable future the biotechnological methods may be applied also for the treatment of high-grade ores and mineral concentrates using adapted native and/or genetically engineered microorganisms. (author)

Conflict minerals from the Democratic Republic of the Congo: global tantalum processing plants, a critical part of the tantalum supply chain

Science.gov (United States)

Papp, John F.

2014-01-01

The U.S. Geological Survey (USGS) analyzes mineral and metal supply chains to identify and describe major components of mineral and metal material flows from ore extraction, through intermediate forms, to a final product. Supply chain analyses may be used (1) to identify risks to the United States associated with the supply of critical and strategic minerals and metals and (2) to provide greater supply chain transparency so that policymakers have the fact-based information needed to formulate public policy. This fact sheet focuses on the post-mining/pre-consumer-product part of the tantalum supply chain. The USGS National Minerals Information Center (NMIC) has been asked by governmental and non-governmental organizations to provide information about tantalum, tin, tungsten, and gold (collectively known as “3TG minerals”) processing facilities worldwide in response to U.S. legislation aimed at identifying and removing the supply chain links between the trade in these minerals and civil unrest in the Democratic Republic of the Congo and adjacent countries.

Characteristics and adaptability of iron- and sulfur-oxidizing microorganisms used for the recovery of metals from minerals and their concentrates

Directory of Open Access Journals (Sweden)

Rawlings Douglas E

2005-05-01

Full Text Available Abstract Microorganisms are used in large-scale heap or tank aeration processes for the commercial extraction of a variety of metals from their ores or concentrates. These include copper, cobalt, gold and, in the past, uranium. The metal solubilization processes are considered to be largely chemical with the microorganisms providing the chemicals and the space (exopolysaccharide layer where the mineral dissolution reactions occur. Temperatures at which these processes are carried out can vary from ambient to 80°C and the types of organisms present depends to a large extent on the process temperature used. Irrespective of the operation temperature, biomining microbes have several characteristics in common. One shared characteristic is their ability to produce the ferric iron and sulfuric acid required to degrade the mineral and facilitate metal recovery. Other characteristics are their ability to grow autotrophically, their acid-tolerance and their inherent metal resistance or ability to acquire metal resistance. Although the microorganisms that drive the process have the above properties in common, biomining microbes usually occur in consortia in which cross-feeding may occur such that a combination of microbes including some with heterotrophic tendencies may contribute to the efficiency of the process. The remarkable adaptability of these organisms is assisted by several of the processes being continuous-flow systems that enable the continual selection of microorganisms that are more efficient at mineral degradation. Adaptability is also assisted by the processes being open and non-sterile thereby permitting new organisms to enter. This openness allows for the possibility of new genes that improve cell fitness to be selected from the horizontal gene pool. Characteristics that biomining microorganisms have in common and examples of their remarkable adaptability are described.

Levels of heavy metals and essential minerals in hair samples of children with autism in Oman: a case-control study.

Science.gov (United States)

Al-Farsi, Yahya M; Waly, Mostafa I; Al-Sharbati, Marwan M; Al-Shafaee, Mohammed A; Al-Farsi, Omar A; Al-Khaduri, Maha M; Gupta, Ishita; Ouhtit, Allal; Al-Adawi, Samir; Al-Said, Mona F; Deth, Richard C

2013-02-01

Toxic levels of heavy metals and low levels of essential minerals have been suggested to play a critical role in the pathogenesis of autism spectrum disorders (ASD). This study documents the levels of heavy metals and essential minerals in hair samples of children with ASD in Muscat, the urbanized capital of Oman, Muscat. The study included 27 children with ASD and 27 matched non-ASD controls. Parental interviews were held and dietary intake questionnaires completed in conjunction with the collection of hair samples. Analysis of heavy metals and essential minerals was carried out by inductively coupled plasma mass spectrometry. Chi-square analysis and non-parametric Fisher's exact tests were used to assess statistical significance. Children with ASD had significantly higher levels of all 11 analyzed heavy metals in their hair samples (P minerals sulfur, sodium, magnesium, potassium, zinc, and iron, but lower levels of calcium and copper in their hair samples. This study corroborates data from previous studies in different parts of the world indicating the presence of elevated levels of heavy metals and selective depletion of essential minerals in the hair of children with ASD.

A novel mineral flotation process using Thiobacillus ferrooxidans.

Science.gov (United States)

Nagaoka, T; Ohmura, N; Saiki, H

1999-08-01

Oxidative leaching of metals by Thiobacillus ferrooxidans has proven useful in mineral processing. Here, we report on a new use for T. ferrooxidans, in which bacterial adhesion is used to remove pyrite from mixtures of sulfide minerals during flotation. Under control conditions, the floatabilities of five sulfide minerals tested (pyrite, chalcocite, molybdenite, millerite, and galena) ranged from 90 to 99%. Upon addition of T. ferrooxidans, the floatability of pyrite was significantly suppressed to less than 20%. In contrast, addition of the bacterium had little effect on the floatabilities of the other minerals, even when they were present in relatively large quantities: their floatabilities remained in the range of 81 to 98%. T. ferrooxidans thus appears to selectively suppress pyrite floatability. As a consequence, 77 to 95% of pyrite was removed from mineral mixtures while 72 to 100% of nonpyrite sulfide minerals was recovered. The suppression of pyrite floatability was caused by bacterial adhesion to pyrite surfaces. When normalized to the mineral surface area, the number of cells adhering to pyrite was significantly larger than the number adhering to other minerals. These results suggest that flotation with T. ferrooxidans may provide a novel approach to mineral processing in which the biological functions involved in cell adhesion play a key role in the separation of minerals.

Alternative Silver Production by Environmental Sound Processing of a Sulfo Salt Silver Mineral Found in Bolivia

Directory of Open Access Journals (Sweden)

Alexander Birich

2018-02-01

Full Text Available Very often, the production of silver causes devastating environmental issues, because of the use of toxic reagents like cyanide and mercury. Due to severe environmental damage caused by humans in the last decades, the social awareness regarding the sustainable production processes is on the rise. Terms like “sustainable” and “green” in product descriptions are becoming more and more popular and producers are forced to satisfy the rising environmental awareness of their customers. Within this work, an alternative environmental sound silver recovery process was developed for a vein type silver ore from Mina Porka, Bolivia. A foregoing characterization of the input material reveals its mineral composition. In the following mineral processing, around 92.9% silver was concentrated by separating 59.5 wt. % of non-silver minerals. Nitric acid leaching of the generated concentrate enabled a silver recovery of up to 98%. The dissolved silver was then separated via copper cementation to generate a metallic silver product of >99% purity. Summarizing all process steps, a silver yield of 87% was achieved in lab scale. A final upscaling trial was conducted to prove the process’ robustness. Within this trial, almost 4 kg of metallic silver with a purity of higher than 99.5 wt. % was produced.

Variations in the mineral composition and heavy metals content of ...

African Journals Online (AJOL)

Babayemi

The parts of Moringa oleifera were assessed for mineral composition and some heavy metal ... cadmium from aqueous system (Sharma et al., 2006). ... Crude extracts and essential oil from M. oleifera possess ... into some probable chemical interactions between the .... processing methods that may lead to detoxification and.

Injury experience in metallic mineral mining, 1991

Energy Technology Data Exchange (ETDEWEB)

1993-10-01

This Mine Safety and Health Administration (MSHA) informational report reviews in detail the occupational injury and illness experience of metallic mineral mining in the United States for 1991. Data reported by operators of mining establishments concerning work injuries are summarized by work location, accident classification, part of body injured, nature of injury, occupation, and principal type of mineral. Related information on employment, worktime, and operating activity also is presented. Data reported by independent contractors performing certain work at mining locations are depicted separately in this report. For ease of comparison with other metal and nonmetallic mineral mining industries and with coal mining, summary reference tabulations are included at the end of both the operator and the contractor sections of this report.

Injury experience in metallic mineral mining, 1992

Energy Technology Data Exchange (ETDEWEB)

1994-05-01

This Mine Safety and Health Administration (MSHA) informational report reviews in detail the occupational injury and illness experience of metallic mineral mining in the United States for 1992. Data reported by operators of mining establishments concerning work injuries are summarized by work location, accident classification, part of body injured, nature of injury, occupation, and principal type of mineral. Related information on employment, worktime, and operating activity also is presented. Data reported by independent contractors performing certain work at mining locations are depicted separately in this report. For ease of comparison with other metal and nonmetallic mineral mining industries and with coal mining, summary reference tabulations are included at the end of both the operator and the contractor sections of this report.

Rock geochemistry related to mineralization processes in geothermal areas

Science.gov (United States)

Kausar, A. Al; Indarto, S.; Setiawan, I.

2018-02-01

Abundant geothermal systems in Indonesia suggest high heat and mass transfer associated with recent or paleovolcanic arcs. In the active geothermal system, the upflow of mixed fluid between late stage hydrothermal and meteoric water might contain mass of minerals associated with epithermal mineralisation process as exemplified at Lihir gold mine in Papua New Guinea. In Indonesia, there is a lack of study related to the precious metals occurrence within active geothermal area. Therefore, in this paper, we investigate the possibility of mineralization process in active geothermal area of Guci, Central Java by using geochemical analysis. There are a lot of conducted geochemical analysis of water, soil and gas by mapping the temperature, pH, Hg and CO2 distribution, and estimating subsurface temperature based on geothermometry approach. Then we also apply rock geochemistry to find minerals that indicate the presence of mineralization. The result from selected geothermal area shows the presence of pyrite and chalcopyrite minerals on the laharic breccias at Kali Putih, Sudikampir. Mineralization is formed within host rock and the veins are associated with gold polymetallic mineralization.

Advances in microbial leaching processes for nickel extraction from lateritic minerals - A review

International Nuclear Information System (INIS)

Behra, Sunil Kumar; Mulaba-Bafubiandi, Antoine Floribert

2015-01-01

Lateritic nickel minerals constitute about 80% of nickel reserves in the world, but their contribution for nickel production is about 40%. The obstacles in extraction of nickel from lateritic minerals are attributed to their very complex mineralogy and low nickel content. Hence, the existing metallurgical techniques are not techno-economically feasible and environmentally sustainable for processing of such complex deposits. At this juncture, microbial mineral processing could be a benevolent approach for processing of lateritic minerals in favor of nickel extraction. The microbial mineral processing route offers many advantages over conventional metallurgical methods as the process is operated under ambient conditions and requires low energy input; thus these processes are relatively simple and environment friendly. Microbial processing of the lateritic deposits still needs improvement to make it industrially viable. Microorganisms play the pivotal role in mineral bio-processing as they catalyze the extraction of metals from minerals. So it is inevitable to explore the physiological and bio-molecular mechanisms involved in this microbe-mineral interaction. The present article offers comprehensive information about the advances in microbial processes for extraction of nickel from laterites.

Advances in microbial leaching processes for nickel extraction from lateritic minerals - A review

Energy Technology Data Exchange (ETDEWEB)

Behra, Sunil Kumar; Mulaba-Bafubiandi, Antoine Floribert [Faculty of Engineering and the Built Environment, University of Johannesburg, (South Africa)

2015-08-15

Lateritic nickel minerals constitute about 80% of nickel reserves in the world, but their contribution for nickel production is about 40%. The obstacles in extraction of nickel from lateritic minerals are attributed to their very complex mineralogy and low nickel content. Hence, the existing metallurgical techniques are not techno-economically feasible and environmentally sustainable for processing of such complex deposits. At this juncture, microbial mineral processing could be a benevolent approach for processing of lateritic minerals in favor of nickel extraction. The microbial mineral processing route offers many advantages over conventional metallurgical methods as the process is operated under ambient conditions and requires low energy input; thus these processes are relatively simple and environment friendly. Microbial processing of the lateritic deposits still needs improvement to make it industrially viable. Microorganisms play the pivotal role in mineral bio-processing as they catalyze the extraction of metals from minerals. So it is inevitable to explore the physiological and bio-molecular mechanisms involved in this microbe-mineral interaction. The present article offers comprehensive information about the advances in microbial processes for extraction of nickel from laterites.

Minerals From the Marine Environment

Science.gov (United States)

Cruickshank, Michael J.

The current interest in minerals centering on, among other things, potential shortages, long-term needs, and deep seabed nodules, accentuates the usefulness and timeliness of this little book authored by a former chairman of the British National Environmental Research Council.In less than 100 pages, the author puts into perspective the potential for producing minerals from offshore areas of the world. After introducing the reader to the ocean environment and the extraordinary variety of the nature of the seabed, the author describes in some detail the variety of minerals found there. This is done in seven separate chapters entitled ‘Bulk and Non-Metallic Minerals From the Seas’ ‘Metals From the Shallow Seas’ ‘Metals From the Deep Oceans’ ‘Minerals From Solution’ ‘Oil and Gas from the Shallow Seas’ ‘Oil and Gas From Deep Waters’ and ‘Coal Beneath the Sea.’ The remaining chapters give a brief regional review of marine minerals distribution for eight areas of significant socioeconomic structure, and a short recapitulation of special problems of mineral recovery in the marine environment including such matters as the effect of water motion on mineral processing and of international law on investments. Glossaries of geological periods and technical terms, a short list of references, and an index complete the work.

Modelling of non-metallic particles motion process in foundry alloys

Directory of Open Access Journals (Sweden)

P. L. Żak

2015-04-01

Full Text Available The behaviour of non-metallic particles in the selected composites was analysed, in the current study. The calculations of particles floating in liquids differing in viscosity were performed. Simulations based on the Stokes equation were made for spherical SiC particles and additionally the particle size influence on Reynolds number was analysed.The movement of the particles in the liquid metal matrix is strictly connected with the agglomerate formation problem.Some of collisions between non-metallic particles lead to a permanent connection between them. Creation of the two spherical particles and a metallic phase system generates the adhesion force. It was found that the adhesion force mainly depends on the surface tension of the liquid alloy and radius of non-metallic particles.

NOVEL IN-SITU METAL AND MINERAL EXTRACTION TECHNOLOGY

Energy Technology Data Exchange (ETDEWEB)

Glenn O' Gorman; Hans von Michaelis; Gregory J. Olson

2004-09-22

This white paper summarizes the state of art of in-situ leaching of metals and minerals, and describes a new technology concept employing improved fragmentation of ores underground in order to prepare the ore for more efficient in-situ leaching, combined with technology to continuously improve solution flow patterns through the ore during the leaching process. The process parameters and economic benefits of combining the new concept with chemical and biological leaching are described. A summary is provided of the next steps required to demonstrate the technology with the goal of enabling more widespread use of in-situ leaching.

Indicator minerals as guides to base metal sulphide mineralisation ...

Indian Academy of Sciences (India)

Zn-bearing minerals that act as indicator minerals for base metal sulphide mineralization from the Proterozoic Betul Belt,central India with special emphasis on their genetic significance have been discussed.Sulphide mineralisation is hosted by the felsic volcanic rocks and has similarities with volcanic-hosted massive ...

Main types of rare-metal mineralization in Karelia

Science.gov (United States)

Ivashchenko, V. I.

2016-03-01

Rare-metal mineralization in Karelia is represented by V, Be, U deposits and In, Re, Nb, Ta, Li, Ce, La, and Y occurrences, which are combined into 17 types of magmatic, pegmatite, albitite-greisen, hydrothermal-metasomatic, sedimentary, and epigenetic groups. The main vanadium resources are localized in the Onega ore district. These are deposits of the Padma group (556 kt) and the Pudozhgorsky complex (1.5 Mt). The REE occurrences are primarily characterized by Ce-La specialization. The perspective of HREE is related to the Eletozero-Tiksheozero alkaline and Salmi anorthosite-rapakivi granite complexes. Rare-metal pegmatites bear complex mineralization with insignificant low-grade resources. The Lobash and Jalonvaara porphyry Cu-Mo deposits are potential sources of rhenium: Re contents in molybdenite are 20-70 and 50-246 ppm and hypothetical resources are 12 and 7.5 t, respectively. The high-grade (˜100 ppm) and metallogenic potential of indium (˜2400 t) make the deposits of the Pitkäranta ore district leading in the category of Russian ore objects most prospective for indium. Despite the diverse rare-metal mineralization known in Karelia, the current state of this kind of mineral commodities at the world market leaves real metallogenic perspective only for V, U, Re, In, and Nb.

Catalysed electrolytic metal oxide dissolution processes

International Nuclear Information System (INIS)

Machuron-Mandard, X.

1994-01-01

The hydrometallurgical processes designed for recovering valuable metals from mineral ores as well as industrial wastes usually require preliminary dissolution of inorganic compounds in aqueous media before extraction and purification steps. Unfortunately, most of the minerals concerned hardly or slowly dissolve in acidic or basic solutions. Metallic oxides, sulfides and silicates are among the materials most difficult to dissolve in aqueous solutions. They are also among the main minerals containing valuable metals. The redox properties of such materials sometimes permit to improve their dissolution by adding oxidizing or reducing species to the leaching solution, which leads to an increase in the dissolution rate. Moreover, limited amounts of redox promoters are required if the redox agent is regenerated continuously thanks to an electrochemical device. Nuclear applications of such concepts have been suggested since the dissolution of many actinide compounds (e.g., UO 2 , AmO 2 , PuC, PuN,...) is mainly based on redox reactions. In the 1980s, improvements of the plutonium dioxide dissolution process have been proposed on the basis of oxidation-reduction principles, which led a few years later to the design of industrial facilities (e.g., at Marcoule or at the french reprocessing plant of La Hague). General concepts and well-established results obtained in France at the Atomic Energy Commission (''Commissariat a l'Energie Atomique'') will be presented and will illustrate applications to industrial as well as analytical problems. (author)

Mineralogy and heavy metal content of secondary mineral salts: A ...

African Journals Online (AJOL)

Secondary minerals associated with acid mine drainage play an important role in metal cycling and may pose a geochemical hazard. The occurrence of secondary minerals indicates prevailing and past geochemical conditions. Detecting and characterising secondary minerals is necessary to the planning of remediation ...

Process for cleaning radioactively contaminated metal surfaces

International Nuclear Information System (INIS)

Mihram, R.G.; Snyder, G.A.

1975-01-01

A process is described for removing radioactive scale from a ferrous metal surface, including the steps of initially preconditioning the surface by contacting it with an oxidizing solution (such as an aqueous solution of an alkali metal permanganate or hydrogen peroxide), then, after removal or decomposition of the oxidizing solution, the metallic surface is contacted with a cleaning solution which is a mixture of a mineral acid and a complexing agent (such as sulfuric acid and oxalic acid), and which preferably contains a corrosion inhibitor. A final step in the process is the treatment of the spent cleaning solution containing radioactive waste materials in solution by adding a reagent selected from the group consisting of calcium hydroxide or potassium permanganate and an alkali metal hydroxide to thereby form easily recovered metallic compounds containing substantially all of the dissolved metals and radioactivity. (auth)

Maintaining and increasing the contribution made to South Africa by the minerals and metals industry

International Nuclear Information System (INIS)

Jochens, P.R.

1985-01-01

This review article first highligts the past performance of the industry and discusses the manner in which the development of the industry has followed a logical progression from mining to the production of mineral and metal products of specification purity. Then the numerous constraints against a greater contribution by the industry are enumerated. Attention is drawn to the extent of further processing that can be undertaken in the context of mining and metallurgical processing, not only to indicate the benefits that can be derived from the added-value conferred on a mineral or metal commodity during each stage of its further processing, but also to point out some important corollaries of further processing. The many opportunities and challenges for an increased contribution by the minerals and metals industry are then reviewed. This major section includes a list of commodities for which increased penetration of export markets could be sought because the increasing resistance level (a term developed in this paper) has not been attained: a list of commodities that are imported at present, many of which could be produced locally on the basis of identified resources and expertise; a list of commodities for which additional uses should be developed so that South Africa, which possesses the largest reserves and is the largest exporter, can increase its production rate; and examples of commodities for which further processing is still at an early stage

Influence of non-clay minerals on the interaction between metallic iron and Callovo-Oxfordian clay fraction

International Nuclear Information System (INIS)

Rivard, C.; Pelletier, M.; Villieras, F.; Michau, N.

2012-01-01

Document available in extended abstract form only. In the context of the geological disposal of high-level radioactive waste, it is of prime importance to understand the interaction mechanisms between the geological matrix, Callovo-Oxfordian clay rock (COx) and metallic iron, from the package overpack. In order to evidence the individual role of each clay component entering in the mineralogy of the COx, interactions between metallic iron and pure clays (smectites, illite and kaolinite) were first conducted. To investigate the role of the other minerals, the reactivity of COx, COx clay fraction (COxCF) and mixtures between COxCF and quartz, calcite or pyrite, was studied. Clays and additional minerals were put in contact with powder metallic iron with a weight ratio iron:clay fixed at 1:3 and a clay:solution ratio of 1:20. Proportions of non-clay minerals were deduced from the average COx composition: 50% clays, 24.5% quartz, 24.5% calcite and 1% pyrite. Batch experiments were carried out in anoxic conditions at 90 deg. C in the presence of background electrolyte (NaCl 0.02 M.L -1 , CaCl 2 0.04 M.L -1 ) in Parr reactors for durations of one, three or nine months. After reaction, solid and liquid phases were separated by centrifugation and characterized by classical techniques combining chemical analyses (liquid analyses, transmission electron microscopy combined with Energy Dispersive of X-rays spectroscopy TEM-EDS), mineralogical (X-ray diffraction), spectroscopic ( 57 Fe Moessbauer) and morphometric techniques (TEM, scanning electron microscopy and N 2 adsorption). For COx, COxCF and all the pure clay phases, major evolutions were observed during the first month, which shows that the oxidation of metallic iron is rapid in our experimental conditions. Release of iron cations in solution, pH increase (8-10) and Eh decrease (reductive conditions) are responsible for the partial dissolution of initial clay phases. Released iron is involved in the crystallization of Fe

Adsorption and redox reactions of heavy metals on synthesized Mn oxide minerals

International Nuclear Information System (INIS)

Feng Xionghan; Zhai Limei; Tan Wenfeng; Liu Fan; He Jizheng

2007-01-01

Several Mn oxide minerals commonly occurring in soils were synthesized by modified or optimized methods. The morphologies, structures, compositions and surface properties of the synthesized Mn oxide minerals were characterized. Adsorption and redox reactions of heavy metals on these minerals in relation to the mineral structures and surface properties were also investigated. The synthesized birnessite, todorokite, cryptomelane, and hausmannite were single-phased minerals and had the typical morphologies from analyses of XRD and TEM/ED. The PZCs of the synthesized birnessite, todorokite and cryptomelane were 1.75, 3.50 and 2.10, respectively. The magnitude order of their surface variable negative charge was: birnessite ≥ cryptomelane > todorokite. The hausmannite had a much higher PZC than others with the least surface variable negative charge. Birnessite exhibited the largest adsorption capacity on heavy metals Pb 2+ , Cu 2+ , Co 2+ , Cd 2+ and Zn 2+ , while hausmannite the smallest one. Birnessite, cryptomelane and todorokite showed the greatest adsorption capacity on Pb 2+ among the tested heavy metals. Hydration tendency (pK 1 ) of the heavy metals and the surface variable charge of the Mn minerals had significant impacts on the adsorption. The ability in Cr(III) oxidation and concomitant release of Mn 2+ varied greatly depending on the structure, composition, surface properties and crystallinity of the minerals. The maximum amounts of Cr(III) oxidized by the Mn oxide minerals in order were (mmol/kg): birnessite (1330.0) > cryptomelane (422.6) > todorokite (59.7) > hausmannite (36.6). - The characteristics of heavy metal adsorption and Cr(III) oxidation on Mn oxide minerals are determined by their structure, composition, surface property and crystallinity

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%.

The review of recent carbonate minerals processing technology

Science.gov (United States)

Solihin

2018-02-01

Carbonate is one of the groups of minerals that can be found in relatively large amount in the earth crust. The common carbonate minerals are calcium carbonate (calcite, aragonite, depending on its crystal structure), magnesium carbonate (magnesite), calcium-magnesium carbonate (dolomite), and barium carbonate (barite). A large amount of calcite can be found in many places in Indonesia such as Padalarang, Sukabumi, and Tasikmalaya (West Java Provence). Dolomite can be found in a large amount in Gresik, Lamongan, and Tuban (East Java Provence). Magnesite is quite rare in Indonesia, and up to the recent years it can only be found in Padamarang Island (South East Sulawesi Provence). The carbonate has been being exploited through open pit mining activity. Traditionally, calcite can be ground to produce material for brick production, be carved to produce craft product, or be roasted to produce lime for many applications such as raw materials for cement, flux for metal smelting, etc. Meanwhile, dolomite has traditionally been used as a raw material to make brick for local buildings and to make fertilizer for coconut oil plant. Carbonate minerals actually consist of important elements needed by modern application. Calcium is one of the elements needed in artificial bone formation, slow release fertilizer synthesis, dielectric material production, etc. Magnesium is an important material in automotive industry to produce the alloy for vehicle main parts. It is also used as alloying element in the production of special steel for special purpose. Magnesium oxide can be used to produce slow release fertilizer, catalyst and any other modern applications. The aim of this review article is to present in brief the recent technology in processing carbonate minerals. This review covers both the technology that has been industrially proven and the technology that is still in research and development stage. One of the industrially proven technologies to process carbonate mineral is

Study on mineral processing technology for abrasive minerals

Energy Technology Data Exchange (ETDEWEB)

Hong, Seong Woong; Yang, Jung Il; Hwang, Seon Kook; Choi, Yeon Ho; Cho, Ken Joon; Shin, Hee Young [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)

1995-12-01

Buyeo Materials in Buyeogun, Choongnam province is a company producing feldspar concentrate, but does not yet utilize the garnet as abrasive material and other useful heavy minerals wasted out from the process of feldspar ore. The purpose of this study is to develop technology and process for the recovery of garnet concentrate. As results, the garnet is defined as ferro manganese garnet. The optimum process for recovery of garnet concentrate is to primarily concentrate heavy minerals from tailings of feldspar processing. And secondly the heavy minerals concentrated is dried and separated garnet concentrate from other heavy minerals. At this time, the garnet concentrate is yield by 0.176%wt from 0.31%wt of heavy minerals in head ore. The garnet concentrate contains 33.35% SiO{sub 2}, 12.20% Al{sub 2}O{sub 3}, 28.47% Fe{sub 2}O{sub 3}, 11.96% MnO. As for utilization of abrasive materials, a fundamental data was established on technology of grinding and classification. (author). 13 refs., 47 figs., 24 tabs.

Environmental Benign Process for Production of Molybdenum Metal from Sulphide Based Minerals

Science.gov (United States)

Rajput, Priyanka; Janakiram, Vangada; Jayasankar, Kalidoss; Angadi, Shivakumar; Bhoi, Bhagyadhar; Mukherjee, Partha Sarathi

2017-10-01

Molybdenum is a strategic and high temperature refractory metal which is not found in nature in free state, it is predominantly found in earth's crust in the form of MoO3/MoS2. The main disadvantage of the industrial treatment of Mo concentrate is that the process contains many stages and requires very high temperature. Almost in every step many gaseous, liquid, solid chemical substances are formed which require further treatment. To overcome the above drawback, a new alternative one step novel process is developed for the treatment of sulphide and trioxide molybdenum concentrates. This paper presents the results of the investigations on molybdenite dissociation (MoS2) using microwave assisted plasma unit as well as transferred arc thermal plasma torch. It is a single step process for the preparation of pure molybdenum metal from MoS2 by hydrogen reduction in thermal plasma. Process variable such as H2 gas, Ar gas, input current, voltage and time have been examined to prepare molybdenum metal. Molybdenum recovery of the order of 95% was achieved. The XRD results confirm the phases of molybdenum metal and the chemical analysis of the end product indicate the formation of metallic molybdenum (Mo 98%).

Effect of soil metal contamination on glyphosate mineralization: role of zinc in the mineralization rates of two copper-spiked mineral soils.

Science.gov (United States)

Kim, Bojeong; Kim, Young Sik; Kim, Bo Min; Hay, Anthony G; McBride, Murray B

2011-03-01

A systematic investigation into lowered degradation rates of glyphosate in metal-contaminated soils was performed by measuring mineralization of [(14)C]glyphosate to (14)CO(2) in two mineral soils that had been spiked with Cu and/or Zn at various loadings. Cumulative (14)CO(2) release was estimated to be approximately 6% or less of the amount of [(14)C]glyphosate originally added in both soils over an 80-d incubation. For all but the highest Cu treatments (400 mg kg(-1)) in the coarse-textured Arkport soil, mineralization began without a lag phase and declined over time. No inhibition of mineralization was observed for Zn up to 400 mg kg(-1) in either soil, suggesting differential sensitivity of glyphosate mineralization to the types of metal and soil. Interestingly, Zn appeared to alleviate high-Cu inhibition of mineralization in the Arkport soil. The protective role of Zn against Cu toxicity was also observed in the pure culture study with Pseudomonas aeruginosa, suggesting that increased mineralization rates in high Cu soil with Zn additions might have been due to alleviation of cellular toxicity by Zn rather than a mineralization specific mechanism. Extensive use of glyphosate combined with its reduced degradation in Cu-contaminated, coarse-textured soils may increase glyphosate persistence in soil and consequently facilitate Cu and glyphosate mobilization in the soil environment. Copyright © 2010 SETAC.

Mercury contamination in agricultural soils from abandoned metal mines classified by geology and mineralization.

Science.gov (United States)

Kim, Han Sik; Jung, Myung Chae

2012-01-01

This survey aimed to compare mercury concentrations in soils related to geology and mineralization types of mines. A total of 16,386 surface soils (0~15 cm in depth) were taken from agricultural lands near 343 abandoned mines (within 2 km from each mine) and analyzed for Hg by AAS with a hydride-generation device. To meaningfully compare mercury levels in soils with geology and mineralization types, three subclassification criteria were adapted: (1) five mineralization types, (2) four valuable ore mineral types, and (3) four parent rock types. The average concentration of Hg in all soils was 0.204 mg kg(-1) with a range of 0.002-24.07 mg kg(-1). Based on the mineralization types, average Hg concentrations (mg kg(-1)) in the soils decreased in the order of pegmatite (0.250) > hydrothermal vein (0.208) > hydrothermal replacement (0.166) > skarn (0.121) > sedimentary deposits (0.045). In terms of the valuable ore mineral types, the concentrations decreased in the order of Au-Ag-base metal mines ≈ base metal mines > Au-Ag mines > Sn-W-Mo-Fe-Mn mines. For parent rock types, similar concentrations were found in the soils derived from sedimentary rocks and metamorphic rocks followed by heterogeneous rocks with igneous and metamorphic processes. Furthermore, farmland soils contained relatively higher Hg levels than paddy soils. Therefore, it can be concluded that soils in Au, Ag, and base metal mines derived from a hydrothermal vein type of metamorphic rocks and pegmatite deposits contained relatively higher concentrations of mercury in the surface environment.

Studies Concerning the Accumulation of Minerals and Heavy Metals in Fruiting Bodies of Wild Mushrooms

International Nuclear Information System (INIS)

Stihi, Claudia; Radulescu, Cristiana; Gheboianu, Anca; Bancuta, Iulian; Popescu, Ion V.; Busuioc, Gabriela

2011-01-01

The minerals and heavy metals play an important role in the metabolic processes, during the growth and development of mushrooms, when they are available in appreciable concentration. In this work the concentrations of Cr, Mn, Fe, Ni, Cu, Zn, Se, Cd and Pb were analyzed using the Flame Atomic Absorption spectrometry (FAAS) together with Energy Dispersive X-ray Fluorescence spectrometry (EDXRF) in 3 wild mushrooms species and their growing substrate, collected from various forestry fields in Dambovita County, Romania. The analyzed mushrooms were: Amanita phalloides, Amanita rubescens and Armillariella mellea. The accumulation coefficients were calculated to assess the mobility of minerals and heavy metals from substrate to mushrooms [1].

‘… a metal conducts and a non-metal doesn't’

Science.gov (United States)

Edwards, P. P.; Lodge, M. T. J.; Hensel, F.; Redmer, R.

2010-01-01

In a letter to one of the authors, Sir Nevill Mott, then in his tenth decade, highlighted the fact that the statement ‘… a metal conducts, and a non-metal doesn’t’ can be true only at the absolute zero of temperature, T=0 K. But, of course, experimental studies of metals, non-metals and, indeed, the electronic and thermodynamic transition between these canonical states of matter must always occur above T=0 K, and, in many important cases, for temperatures far above the absolute zero. Here, we review the issues—theoretical and experimental—attendant on studies of the metal to non-metal transition in doped semiconductors at temperatures close to absolute zero (T=0.03 K) and fluid chemical elements at temperatures far above absolute zero (T>1000 K). We attempt to illustrate Mott’s insights for delving into such complex phenomena and experimental systems, finding intuitively the dominant features of the science, and developing a coherent picture of the different competing electronic processes. A particular emphasis is placed on the idea of a ‘Mott metal to non-metal transition’ in the nominally metallic chemical elements rubidium, caesium and mercury, and the converse metallization transition in the nominally non-metal elements hydrogen and oxygen. We also review major innovations by D. A. Goldhammer (Goldhammer 1913 Dispersion und absorption des lichtes) and K. F. Herzfeld (Herzfeld 1927 Phys. Rev. 29, 701–705. (doi:10.1103/PhysRev.29.701)) in a pre-quantum theory description of the metal–non-metal transition, which emphasize the pivotal role of atomic properties in dictating the metallic or non-metallic status of the chemical elements of the periodic table under ambient and extreme conditions; a link with Pauling’s ‘metallic orbital’ is also established here. PMID:20123742

Non-autoclaved aerated concrete with mineral additives

Science.gov (United States)

Il'ina, L. V.; Rakov, M. A.

2016-01-01

We investigated the effect of joint grinding of Portland cement clinker, silica and carbonate components and mineral additives to specific surface of 280 - 300 m2/kg on the properties (strength, average density and thermal conductivity) of non-autoclaved aerated concrete, and the porosity of the hardened cement paste produced from Portland cement clinker with mineral additives. The joint grinding of the Portland cement clinker with silica and carbonate components and mineral additives reduces the energy consumption of non-autoclaved aerated concrete production. The efficiency of mineral additives (diopside, wollastonite) is due to the closeness the composition, the type of chemical bonds, physical and chemical characteristics (specific enthalpy of formation, specific entropy) to anhydrous clinker minerals and their hydration products. Considering the influence of these additions on hydration of clinker minerals and formation of hardened cement paste structure, dispersed wollastonite and diopside should be used as mineral additives. The hardness and, consequently, the elastic modulus of diopside are higher than that of hardened cement paste. As a result, there is a redistribution of stresses in the hardened cement paste interporous partitions and hardening, both the partitions and aerated concrete on the whole. The mineral additives introduction allowed to obtain the non-autoclaved aerated concrete with average density 580 kg/m3, compressive strength of 3.3 MPa and thermal conductivity of 0.131 W/(m.°C).

Standard practice for process compensated resonance testing via swept sine input for metallic and Non-Metallic parts

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 This practice describes a general procedure for using the process compensated resonance testing (PCRT) via swept sine input method to identify metallic and non-metallic parts’ resonant pattern differences that can be used to indentify parts with anomalies causing deficiencies in the expected performance of the part in service. This practice is intended for use with instruments capable of exciting, measuring, recording, and analyzing multiple whole body mechanical vibration resonant frequencies within parts exhibiting acoustical ringing in the audio, or ultrasonic, resonant frequency ranges, or both. PCRT is used in the presence of manufacturing process variance to distinguish acceptable parts from those containing significant anomalies in physical characteristics expected to significantly alter the performance. Such physical characteristics include, but are not limited to, cracks, voids, porosity, shrink, inclusions, discontinuities, grain and crystalline structure differences, density related anomalies...

ROCKS & MINERALS DETERMINATION AND ANALYSIS

Institute of Scientific and Technical Information of China (English)

2015-01-01

20150204 Abaydulla Alimjan(Department of Chemistry and Environmental Sciences,Kashgar Teachers College,Kashgar 844006,China);Cheng Chunying Non-Metallic Element Composition Analysis of Non-Ferrous Metal Ores from Oytagh Town,Xinjiang(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,33(1),2014,p.44-50,5illus.,4tables,28refs.)Key words:nonferrous metals ore,nonmetals,chemical analysis,thermogravimetric analysis Anions in non-ferrous ore materials

Effects of Medium-Term Amendment with Diversely Processed Sewage Sludge on Soil Humification—Mineralization Processes and on Cu, Pb, Ni, and Zn Bioavailability

Directory of Open Access Journals (Sweden)

Gabriella Rossi

2018-03-01

Full Text Available The organic fraction of sewage sludge administered to agricultural soil can contribute to slowing down the loss of soil’s organic carbon and, in some cases, can improve the physical and mechanical properties of the soil. One of the main constraints to the agricultural use of sewage sludge is its heavy metals content. In the long term, agricultural administration of sewage sludge to soil could enhance the concentration of soil heavy metals (as total and bioavailable fractions. The aim of this research was to evaluate the effects of medium-term fertilization with diversely processed sewage sludge on the soil’s organic carbon content and humification–mineralization processes, on the physical–mechanical properties of soil and their influence on the pool of potentially bioavailable heavy metals, in order to assess their effectiveness as soil organic amendments. After eight years of sludge administration; an increase in the concentrations of bioavailable form was evidenced in all the heavy metals analyzed; independently of the type of sludge administered. The form of sludge administration (liquid, dehydrated, composted has differently influenced the soil humification–mineralization processes and the physical–mechanical properties of soil. The prolonged amendment with composted sewage sludge contributed to keeping the soil humification–mineralization process in equilibrium and to improving the physical and mechanical qualities of the treated soil.

Life-Cycle environmental impact assessment of mineral industries

Science.gov (United States)

Hisan Farjana, Shahjadi; Huda, Nazmul; Parvez Mahmud, M. A.

2018-05-01

Mining is the extraction and processing of valuable ferro and non-ferro metals and minerals to be further used in manufacturing industries. Valuable metals and minerals are extracted from the geological deposits and ores deep in the surface through complex manufacturing technologies. The extraction and processing of mining industries involve particle emission to air or water, toxicity to the environment, contamination of water resources, ozone layer depletion and most importantly decay of human health. Despite all these negative impacts towards sustainability, mining industries are working throughout the world to facilitate the employment sector, economy and technological growth. The five most important miners in the world are South Africa, Russia, Australia, Ukraine, Guinea. The mining industries contributes to their GDP significantly. However, the most important issue is making the mining world sustainable thus reducing the emissions. To address the environmental impacts caused by the mining sectors, this paper is going to analyse the environmental impacts caused by the 5 major minerals extraction processes, which are bauxite, ilmenite, iron ore, rutile and uranium by using the life-cycle impact assessment technologies. The analysis is done here using SimaPro software version 8.4 using ReCipe, CML and Australian indicator method.

Leaching behavior of mineral processing waste: Comparison of batch and column investigations

Energy Technology Data Exchange (ETDEWEB)

Al-Abed, Souhail R. [National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (United States)], E-mail: al-abed.souhail@epa.gov; Jegadeesan, G. [Pegasus Technical Services Inc., 46 East Hollister Street, Cincinnati, OH 45219 (United States); Purandare, J. [Englandgeosystem Inc., 15375 Barranca Pkwy, Suite F-106, Irvine, CA 92618 (United States); Allen, D. [National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (United States)

2008-05-30

In this study, a comparison of laboratory batch and column experiments on metal release profile from a mineral processing waste (MPW) is presented. Batch (equilibrium) and column (dynamic) leaching tests were conducted on ground MPW at different liquid-solid ratios (LS) to determine the mechanisms controlling metal release. Additionally, the effect of pH on metal release is also discussed. It was observed that acidic pH conditions induced dissolution of As, Zn and Cu. Negligible leaching at alkaline pH was observed. However, Se depicted amphoteric behavior with high release at low and high pH. The batch and column data showed that As and Se release increased with LS ratio, while that of Cu and Zn increased initially and tapered towards equilibrium values at high LS ratios. The results on metal release from the MPW suggested that dissolution of the metal was the controlling mechanism. Leaching profiles from the batch and column data corresponded well for most LS ratios. This is most likely due to the acidic character of the waste, minimal changes in pH during the column operation and granular structure of the waste. From a waste management perspective, low cost batch equilibrium studies in lieu of high cost column experiments can be used for decision making on its disposal only when the waste exhibits characteristics similar to the mineral processing waste.

Leaching behavior of mineral processing waste: Comparison of batch and column investigations

International Nuclear Information System (INIS)

Al-Abed, Souhail R.; Jegadeesan, G.; Purandare, J.; Allen, D.

2008-01-01

In this study, a comparison of laboratory batch and column experiments on metal release profile from a mineral processing waste (MPW) is presented. Batch (equilibrium) and column (dynamic) leaching tests were conducted on ground MPW at different liquid-solid ratios (LS) to determine the mechanisms controlling metal release. Additionally, the effect of pH on metal release is also discussed. It was observed that acidic pH conditions induced dissolution of As, Zn and Cu. Negligible leaching at alkaline pH was observed. However, Se depicted amphoteric behavior with high release at low and high pH. The batch and column data showed that As and Se release increased with LS ratio, while that of Cu and Zn increased initially and tapered towards equilibrium values at high LS ratios. The results on metal release from the MPW suggested that dissolution of the metal was the controlling mechanism. Leaching profiles from the batch and column data corresponded well for most LS ratios. This is most likely due to the acidic character of the waste, minimal changes in pH during the column operation and granular structure of the waste. From a waste management perspective, low cost batch equilibrium studies in lieu of high cost column experiments can be used for decision making on its disposal only when the waste exhibits characteristics similar to the mineral processing waste

Multi-scale interactions of geological processes during mineralization: cascade dynamics model and multifractal simulation

Directory of Open Access Journals (Sweden)

L. Yao

2011-03-01

Full Text Available Relations between mineralization and certain geological processes are established mostly by geologist's knowledge of field observations. However, these relations are descriptive and a quantitative model of how certain geological processes strengthen or hinder mineralization is not clear, that is to say, the mechanism of the interactions between mineralization and the geological framework has not been thoroughly studied. The dynamics behind these interactions are key in the understanding of fractal or multifractal formations caused by mineralization, among which singularities arise due to anomalous concentration of metals in narrow space. From a statistical point of view, we think that cascade dynamics play an important role in mineralization and studying them can reveal the nature of the various interactions throughout the process. We have constructed a multiplicative cascade model to simulate these dynamics. The probabilities of mineral deposit occurrences are used to represent direct results of mineralization. Multifractal simulation of probabilities of mineral potential based on our model is exemplified by a case study dealing with hydrothermal gold deposits in southern Nova Scotia, Canada. The extent of the impacts of certain geological processes on gold mineralization is related to the scale of the cascade process, especially to the maximum cascade division number n_max. Our research helps to understand how the singularity occurs during mineralization, which remains unanswered up to now, and the simulation may provide a more accurate distribution of mineral deposit occurrences that can be used to improve the results of the weights of evidence model in mapping mineral potential.

Methods of mineral potential assessment of uranium deposits: A mineral systems approach

International Nuclear Information System (INIS)

Jaireth, S.

2014-01-01

deposit). The five questions include: i) what is the architecture and size of the system; ii) what is P-T and geodynamic history of the system; iii) what is the nature of the fluids and fluid reservoirs in the system; iv) what is the nature of fluid pathways; and v) what is the chemistry of metal transport and deposition in space as well as time. Analysis of fertile mineral systems can provide useful information on geological processes essential to form an economic mineral deposit in an area. Mappable features of these processes in geological datasets can then be used to estimate probabilities visualised in the form of mineral potential, prospectivity and favourability maps. The probabilities (levels of mineral potential, favourability index) can be either shown using non-numerical (high, moderate and low), ordinal (numbers expressing ranking) and cardinal (numbers expressing quantities) scales. This paper will discuss advantages and disadvantages of various GIS-based methods of qualitative assessment and will also present a number of case studies illustrating mineral potential assessment of uranium deposits carried out in Geoscience Australia. (author)

Enhancement of Au-Ag-Te contents in tellurium-bearing ore minerals via bioleaching

Science.gov (United States)

Choi, Nag-Choul; Cho, Kang Hee; Kim, Bong Ju; Lee, Soonjae; Park, Cheon Young

2018-03-01

The purpose of this study was to enhance the content of valuable metals, such as Au, Ag, and Te, in tellurium-bearing minerals via bioleaching. The ore samples composed of invisible Au and Au paragenesis minerals (such as pyrite, chalcopyrite, sphalerite and galena) in combination with tellurium-bearing minerals (hessite, sylvanite and Tellurobismuthite) were studied. Indigenous microbes from mine drainage were isolated and identified as Acidithiobacillus ferrooxidans, which were used in bioleaching after adaption to copper. The effect of the microbial adaption on the bioleaching performance was then compared with the results produced by the non-adaptive process. The microbial adaption enhanced the Au-Ag-Te contents in biological leaching of tellurium-bearing ore minerals. This suggests that bioleaching with adapted microbes can be used both as a pretreatment and in the main recovery processes of valuable metals.

Coastal placer minerals

Digital Repository Service at National Institute of Oceanography (India)

Iyer, S.D.; Gujar, A.R.

to be processed and purified to extract the metal either by sulphate or chloride route. The economical aspects of placer mining would involve the cost to benefit ratio, which would encompass the money Selective sorting has resulted in two distinct sediments... or mineral at the national and international levels. Interestingly, though gold is the most sought metal and the prices per gram keep rising, there are others that are much more costly such as diamond and rare earth metals. Uses of Heavy Minerals...

Binding of heavy metal ions in aggregates of microbial cells, EPS and biogenic iron minerals measured in-situ using metal- and glycoconjugates-specific fluorophores

Science.gov (United States)

Hao, Likai; Guo, Yuan; Byrne, James M.; Zeitvogel, Fabian; Schmid, Gregor; Ingino, Pablo; Li, Jianli; Neu, Thomas R.; Swanner, Elizabeth D.; Kappler, Andreas; Obst, Martin

2016-05-01

Aggregates consisting of bacterial cells, extracellular polymeric substances (EPS) and Fe(III) minerals formed by Fe(II)-oxidizing bacteria are common at bulk or microscale chemical interfaces where Fe cycling occurs. The high sorption capacity and binding capacity of cells, EPS, and minerals controls the mobility and fate of heavy metals. However, it remains unclear to which of these component(s) the metals will bind in complex aggregates. To clarify this question, the present study focuses on 3D mapping of heavy metals sorbed to cells, glycoconjugates that comprise the majority of EPS constituents, and Fe(III) mineral aggregates formed by the phototrophic Fe(II)-oxidizing bacteria Rhodobacter ferrooxidans SW2 using confocal laser scanning microscopy (CLSM) in combination with metal- and glycoconjugates-specific fluorophores. The present study evaluated the influence of glycoconjugates, microbial cell surfaces, and (biogenic) Fe(III) minerals, and the availability of ferrous and ferric iron on heavy metal sorption. Analyses in this study provide detailed knowledge on the spatial distribution of metal ions in the aggregates at the sub-μm scale, which is essential to understand the underlying mechanisms of microbe-mineral-metal interactions. The heavy metals (Au3+, Cd2+, Cr3+, CrO42-, Cu2+, Hg2+, Ni2+, Pd2+, tributyltin (TBT) and Zn2+) were found mainly sorbed to cell surfaces, present within the glycoconjugates matrix, and bound to the mineral surfaces, but not incorporated into the biogenic Fe(III) minerals. Statistical analysis revealed that all ten heavy metals tested showed relatively similar sorption behavior that was affected by the presence of sorbed ferrous and ferric iron. Results in this study showed that in addition to the mineral surfaces, both bacterial cell surfaces and the glycoconjugates provided most of sorption sites for heavy metals. Simultaneously, ferrous and ferric iron ions competed with the heavy metals for sorption sites on the organic

A study of liberation and separation process of metals from printed circuit boards (PCBs) scrap

International Nuclear Information System (INIS)

Noorliyana, H.A.; Zaheruddin, K.; Mohd Fazlul Bari; M. Sri Asliza; Nurhidayah, A.Z.; Kamarudin, H.

2009-01-01

Since the metallic elements are covered with or encapsulated by various plastic or ceramic materials on printed circuit boards, a mechanical pre-treatment process allowing their liberation and separation is first needed in order to facilitate their efficient extraction with hydrometallurgy route. Even though many studies have been performed on the mechanical pre-treatment processing for the liberation and separation of the metallic components of printed circuit boards scrap, further studies are required to pave the way for efficient recycling of waste printed circuit boards through a combination of mechanical pre-treatment and hydrometallurgical technology. In this work, a fundamental study has been carried out on the mechanical pre-treatment that is necessary to recover metallic concentrates from printed circuit boards scraps. The most important problem is to separate or release particles from the associated gangue minerals at the possible liberation particle size. The distribution of metallic elements has been also investigated in relation to the particle size of the milled printed circuit boards. The samples of printed circuit boards were separated into the magnetic and non-magnetic fractions by Rare-earth Roll Magnetic separator. Thereafter, the magnetic and non-magnetic fractions were separated to heavy fraction (metallic elements) and light fraction (plastic) by Mozley Laboratory Table Separator. The recovery ratios and the evaluation of the metallic concentrates recovered by each separation process were also investigated. This study is expected to provide useful data for the efficient mechanical separation of metallic components from printed circuit boards scraps. (author)

Hydrometalurgical processes for mineral complexes

International Nuclear Information System (INIS)

Barskij, L.A.; Danil'chenko, L.M.

1977-01-01

Requirements for the technology of the processing of ores including uranium ores and principal stages of the working out of technological schemes are described in brief. There are reference data on commercial minerals and ores including uranium-thorium ores, their classification with due regard for physical, chemical and superficial properties which form the basis for ore-concentrating processes. There are also presented the classification of minerals including uranium minerals by their flotation ability, flotation regimes of minerals, structural-textural characteristics of ores, genetic types of ore formations and their concentrating ability, algorithmization of the apriori evaluation of the concentration and technological diagnostics of the processing of ores. The classification of ore concentration technique is suggested

Bone mineral density and blood metals in premenopausal women

International Nuclear Information System (INIS)

Pollack, A.Z.; Mumford, S.L.; Wactawski-Wende, J.; Yeung, E.; Mendola, P.; Mattison, D.R.; Schisterman, E.F.

2013-01-01

Exposure to metals, specifically cadmium, lead, and mercury, is widespread and is associated with reduced bone mineral density (BMD) in older populations, but the associations among premenopausal women are unclear. Therefore, we evaluated the relationship between these metals in blood and BMD (whole body, total hip, lumbar spine, and non-dominant wrist) quantified by dual energy X-ray absorptiometry in 248 premenopausal women, aged 18–44. Participants were of normal body mass index (mean BMI 24.1), young (mean age 27.4), 60% were white, 20% non-Hispanic black, 15% Asian, and 6% other race group, and were from the Buffalo, New York region. The median (interquartile range) level of cadmium was 0.30 μg/l (0.19–0.43), of lead was 0.86 μg/dl (0.68–1.20), and of mercury was 1.10 μg/l (0.58–2.00). BMD was treated both as a continuous variable in linear regression and dichotomized at the 10th percentile for logistic regression analyses. Mercury was associated with reduced odds of decreased lumbar spine BMD (0.66, 95% confidence interval: 0.44, 0.99), but overall, metals at environmentally relevant levels of exposure were not associated with reduced BMD in this population of healthy, reproductive-aged women. Further research is needed to determine if the blood levels of cadmium, lead, and mercury in this population are sufficiently low that there is no substantive impact on bone, or if effects on bone can be expected only at older ages.

Bone mineral density and blood metals in premenopausal women

Energy Technology Data Exchange (ETDEWEB)

Pollack, A.Z., E-mail: pollacka@mail.nih.gov [Epidemiology Branch, Division of Epidemiology, Statistics, and Prevention Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD (United States); Mumford, S.L. [Epidemiology Branch, Division of Epidemiology, Statistics, and Prevention Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD (United States); Wactawski-Wende, J. [Department of Social and Preventive Medicine, University at Buffalo, State University of New York, Buffalo, NY (United States); Yeung, E.; Mendola, P.; Mattison, D.R.; Schisterman, E.F. [Epidemiology Branch, Division of Epidemiology, Statistics, and Prevention Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD (United States)

2013-01-15

Exposure to metals, specifically cadmium, lead, and mercury, is widespread and is associated with reduced bone mineral density (BMD) in older populations, but the associations among premenopausal women are unclear. Therefore, we evaluated the relationship between these metals in blood and BMD (whole body, total hip, lumbar spine, and non-dominant wrist) quantified by dual energy X-ray absorptiometry in 248 premenopausal women, aged 18-44. Participants were of normal body mass index (mean BMI 24.1), young (mean age 27.4), 60% were white, 20% non-Hispanic black, 15% Asian, and 6% other race group, and were from the Buffalo, New York region. The median (interquartile range) level of cadmium was 0.30 {mu}g/l (0.19-0.43), of lead was 0.86 {mu}g/dl (0.68-1.20), and of mercury was 1.10 {mu}g/l (0.58-2.00). BMD was treated both as a continuous variable in linear regression and dichotomized at the 10th percentile for logistic regression analyses. Mercury was associated with reduced odds of decreased lumbar spine BMD (0.66, 95% confidence interval: 0.44, 0.99), but overall, metals at environmentally relevant levels of exposure were not associated with reduced BMD in this population of healthy, reproductive-aged women. Further research is needed to determine if the blood levels of cadmium, lead, and mercury in this population are sufficiently low that there is no substantive impact on bone, or if effects on bone can be expected only at older ages.

Geology mineralogy, structure and texture of Agh-Otagh base- precious metal mineralization (North Takab

Directory of Open Access Journals (Sweden)

Nahid Rahmati

2017-07-01

Full Text Available The Agh-Otagh mineralization area in the north of Takab, was formed within the andesistic tuffaceous rocks of the Oligo- Miocene age. Mineralization include polymetallic (Cu-Pb-Zn-Au-Ag quartz veins and silicified zones, which occurred as breccia and vein- veinlets with comb, cockade and disseminated textures. Chalcopyrite, pyrite, galena and sphalerite are common ore minerals. Alteration zones consist of silicification, sericitization, argillitic, propelitic and carbonatization. Cu-Au mineralization is associated with silicification and sericitization. Analytical results of the samples from the ore- bearing quartz veins and the silicified zones indicate that the highest grade for Au is 664 ppb (ave.181 ppb. The highest and the average grades for Ag, Cu, Pb, and Zn are 120 ppm (300 ppm, 1.3 % (0.38 %, 5.5 % (0.06 % and 4.5 % (0.28 %, respectively. The investigations indicate that the Agh-Otagh mineralization was formed in four stages. In the first stage or the pre-mineralization stage, the host rock, as a result of hydrothermal process, underwent brecciation and some quartz veins and siliceous cap were formed. In the second stage or the mineralization stage the sulfide minerals formed within the quartz veins and silicification zones developed at the third stage, some unmineralized quartz, barite and carbonate vein- veinlets crosscut the previous stages. The last stage of mineralization related to supergene processes. Based on geological, mineralogical, alteration, structural and textural evidences, the Agh-Otagh base- precious metal mineralization is similar to the medium sulfidation epithermal deposits.

Catalytic extraction processing of contaminated scrap metal

International Nuclear Information System (INIS)

Griffin, T.P.; Johnston, J.E.

1994-01-01

The contract was conceived to establish the commercial capability of Catalytic Extraction Processing (CEP) to treat contaminated scrap metal in the DOE inventory. In so doing, Molten Metal Technology, Inc. (MMT), pursued the following objectives: demonstration of the recycling of ferrous and non-ferrous metals--to establish that radioactively contaminated scrap metal can be converted to high-grade, ferrous and non-ferrous alloys which can be reused by DOE or reintroduced into commerce; immobilize radionuclides--that CEP will concentrate the radionuclides in a dense vitreous phase, minimize secondary waste generation and stabilize and reduce waste volume; destroy hazardous organics--that CEP will convert hazardous organics to valuable industrial gases, which can be used as feed gases for chemical synthesis or as an energy source; recovery volatile heavy metals--that CEP's off-gas treatment system will capture volatile heavy metals, such as mercury and lead; and establish that CEP is economical for processing contaminated scrap metal in the DOE inventory--that CEP is a more cost-effective and, complete treatment and recycling technology than competing technologies for processing contaminated scrap. The process and its performance are described

Process technology - rare and refractory metals

International Nuclear Information System (INIS)

Gupta, C.K.; Bose, D.K.

1989-01-01

India has fairly rich resreves of rare and refractory metals. Abundant sources of ilmenite, rutile, zircon and rare earths are found in the placer deposits of the southern and eastern coasts of the country. Columbite-tantalite occur in mica and the mining belts of Bihar and cassiterite deposits are found in Bastar (Madhya Pradesh). Vanadium as a minor associate occurs in bauxites and in the vast deposits of titaniferrous magnetites. Over the years, research and development and pilot plant works in many research organisations in India have built up a sound technological base in the country for process metallurgy of many refractory and rare earth metals starting from their indigenous sources. The present paper provides a comprehensive view of the developments that have taken place till now on the processing of various refractory and rare earth metals with particular reference to the extensive work carried out at the Department of Atomic Energy. The coverage includes mineral benification separation of individual elements, preparation of pure intermediates, techniques of reduction to metal and final purification. The paper also reviews some of the recent developments that have been taken place in these fields and the potential application of these metals in the foreseeable future. (author). 22 refs., 18 fi g., 7 tabs

Mineral composition and heavy metal contamination of sediments originating from radium rich formation water.

Science.gov (United States)

Bzowski, Zbigniew; Michalik, Bogusław

2015-03-01

Radium rich formation water is often associated with fossil fuels as crude oil, natural gas and hard coal. As a result of fossil fuels exploitation high amount of such water is released into environment. In spite of the high radium content such waters create a serious radiation risk neither to humans nor biota directly. First and foremost due to very high mineralization they are not drinkable at all. But after discharge chemical and physical conditions are substantially changed and sediments which additionally concentrated radium are arising. Due to features of technological processes such phenomenon is very intensive in underground coal mining where huge volume of such water must be pumped into surface in order to keep underground galleries dry. Slightly different situation occurs in oil rigs, but finally also huge volume of so called process water is pumped into environment. Regardless their origin arising sediments often contain activity concentration of radium isotopes exceeding the clearance levels set for naturally occurring radioactive materials (NORM) (Council Directive, 2013). The analysis of metals and minerals content showed that besides radioactivity such sediments contain high amount of metals geochemically similar to radium as barium, strontium and lead. Correlation analysis proved that main mechanism leading to sediment creation is co-precipitation radium with these metals as a sulfate. The absorption on clay minerals is negligible even when barium is not present in significant quantities. Owing to very low solubility of sulfates radium accumulated in this way should not migrate into environment in the neighborhood of a site where such sediment were deposited. Copyright © 2014 Elsevier Ltd. All rights reserved.

IMMOBILIZATION OF HEAVY METALS IN SOILS AND WATER BY A MANGANESE MINERAL

Science.gov (United States)

A synthesized Mn mineral used in study on adsorption of heavy metals from water has shown a great adsorption capability for Pb, Cu, Cd, Co, Ni and Zn on this mineral over a pH range from 2 to 8. The retention of Pb on this mineral was as high as 10% of its weight. Application of ...

Towards sustainable processing of columbite group minerals: elucidating the relation between dielectric properties and physico-chemical transformations in the mineral phase.

Science.gov (United States)

Sanchez-Segado, Sergio; Monti, Tamara; Katrib, Juliano; Kingman, Samuel; Dodds, Chris; Jha, Animesh

2017-12-21

Current methodologies for the extraction of tantalum and niobium pose a serious threat to human beings and the environment due to the use of hydrofluoric acid (HF). Niobium and tantalum metal powders and pentoxides are widely used for energy efficient devices and components. However, the current processing methods for niobium and tantalum metals and oxides are energy inefficient. This dichotomy between materials use for energy applications and their inefficient processing is the main motivation for exploring a new methodology for the extraction of these two oxides, investigating the microwave absorption properties of the reaction products formed during the alkali roasting of niobium-tantalum bearing minerals with sodium bicarbonate. The experimental findings from dielectric measurement at elevated temperatures demonstrate an exponential increase in the values of the dielectric properties as a result of the formation of NaNbO 3 -NaTaO 3 solid solutions at temperatures above 700 °C. The investigation of the evolution of the dielectric properties during the roasting reaction is a key feature in underpinning the mechanism for designing a new microwave assisted high-temperature process for the selective separation of niobium and tantalum oxides from the remainder mineral crystalline lattice.

New and non-traditional mineral raw materials deposits, perspectives of use

International Nuclear Information System (INIS)

Beyseev, O.; Beyseev, A.; Baichigasov, I.; Sergev, E.; Shakirova, G.

1996-01-01

Deposits of new and non-traditional kinds of mineral raw material are revealed, explored and prepared to industrial recovery in Kazakstan, that can be used in frames of conversion process to create new materials with unique properties, to prepare base for new technologies elaboration, and to achieve appreciable economic benefit. These deposits are located mostly in geographic and economic conditions of advanced infrastructure and mining works network, favorable for recovery.On the tests results the following is of heaviest interest: RHODUCITE, NEMALITE-CONTAINING CHRYSOTILE-ASBESTOS, NICKEL-CONTAINING SILICATE-ASBOLAN ORES, MEDICINAL MINERALS, SHUNGITES, FULLERENES, RAW QUARTZ MINERALS - the group of deposits containing 5 min tons of high quality quartz good for manufacture of cut-glass and fibre-optical articles, is explored in details. There are also deposits of other kinds of non-traditional strategic mineral raw material in the Republic of Kazakstan - natural fillers, that can be used in the national economy of the country and bring considerable economic benefit: chrysotile-asbestos, amphibole-asbestos, talk, vollastonite, tremolite, actinolite, vermiculite, zeolite, etc

Valuable metals - recovery processes, current trends, and recycling strategies

Energy Technology Data Exchange (ETDEWEB)

Froehlich, Peter; Lorenz, Tom; Martin, Gunther; Brett, Beate; Bertau, Martin [Institut fuer Technische Chemie, TU Bergakademie Freiberg, Leipziger Strasse 29, 09599, Freiberg (Germany)

2017-03-01

This Review provides an overview of valuable metals, the supply of which has been classified as critical for Europe. Starting with a description of the current state of the art, novel approaches for their recovery from primary resources are presented as well as recycling processes. The focus lies on developments since 2005. Chemistry strategies which are used in metal recovery are summarized on the basis of the individual types of deposit and mineral. In addition, the economic importance as well as utilization of the metals is outlined. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Uptake of heavy metals by Typha capensis from wetland sites polluted by effluent from mineral processing plants: implications of metal-metal interactions.

Science.gov (United States)

Zaranyika, M F; Nyati, W

2017-10-01

The aim of the present work was to demonstrate the existence of metal-metal interactions in plants and their implications for the absorption of toxic elements like Cr. Typha capensis , a good accumulator of heavy metals, was chosen for the study. Levels of Fe, Cr, Ni, Cd, Pb, Cu and Zn were determined in the soil and roots, rhizomes, stems and leaves of T. capensis from three Sites A, B and C polluted by effluent from a chrome ore processing plant, a gold ore processing plant, and a nickel ore processing plant, respectively. The levels of Cr were extremely high at Site A at 5415 and 786-16,047 μg g -1 dry weight in the soil and the plant, respectively, while the levels of Ni were high at Site C at 176 and 24-891 μg g -1 in the soil and the plant, respectively. The levels of Fe were high at all three sites at 2502-7500 and 906-13,833 μg g -1 in the soil and plant, respectively. For the rest of the metals, levels were modest at 8.5-148 and 2-264 μg g -1 in the soil and plant, respectively. Pearson's correlation analysis confirmed mutual synergistic metal-metal interactions in the uptake of Zn, Cu, Co, Ni, Fe, and Cr, which are attributed to the similarity in the radii and coordination geometry of the cations of these elements. The implications of such metal-metal interactions (or effects of one metal on the behaviour of another) on the uptake of Cr, a toxic element, and possible Cr detoxification mechanism within the plant, are discussed.

Do the levels of selected metals differ significantly between the roots of carious and non-carious teeth?

International Nuclear Information System (INIS)

Malara, Piotr; Kwapulinski, Jerzy; Malara, Beata

2006-01-01

Since the metals deposited in teeth during formation and mineralization processes are to a large extent retained, human teeth receive a considerable attention as the indicators of the heavy metal exposure. The use of permanent teeth is limited because the extraction of healthy permanent teeth just for this purpose is hardly acceptable. As the issue of the loss of elements from a carious lesion in the coronal part of a tooth remains controversial, the valuable material could only be the root of carious and fractured permanent teeth. However, to ensure the validity of the results, it should be ascertained that the levels of certain toxic and essential elements do not differ significantly between the roots of non-carious and carious teeth, and therefore this is the aim of this project. The levels of cadmium, chromium, copper, iron, manganese, lead, zinc, potassium, sodium, calcium and magnesium were determined in the roots of 344 permanent teeth (189 carious and 155 caries-free teeth) from the residents of Ruda Slaska, Poland, aged 18 to 34. No statistically significant difference between the concentration of these metals in the roots of non-carious and carious teeth was found. This finding applies to both the general population and after the grouping by donor's gender and tooth type. The concentration of lead, iron, calcium and manganese in the roots of non-carious and carious teeth exhibited dependence upon tooth type, as well as the concentration of potassium in the roots of carious teeth. Since the mineral composition of the roots of permanent teeth is similar for the non-carious, as well as the carious teeth, they can be indiscriminately selected for the tests required by a research project, as they will produce the comparable results. However, in the case of lead, iron, calcium, potassium and manganese, the comparison should be made after grouping by tooth type

EIS and adjunct electrical modeling for material selection by evaluating two mild steels for use in super-alkaline mineral processing

DEFF Research Database (Denmark)

Bakhtiyari, Leila; Moghimi, Fereshteh; Mansouri, Seyed Soheil

2012-01-01

The production of metal concentrates during mineral processing of ferrous and non-ferrous metals involves a variety of highly corrosive chemicals which deteriorate common mild steel as the material of choice in the construction of such lines, through rapid propagation of localized pitting...... in susceptible parts, often in sensitive areas. This requires unscheduled maintenance and plant shut down. In order to test the corrosion resistance of different available materials as replacement materials, polarization and electrochemical impedance spectroscopy (EIS) tests were carried out. The EIS numerical...... software-enhanced polarization resistance, and reduced capacitance added to much diminished current densities, verified the acceptable performance of CK45 compared with high priced stainless steel substitutes with comparable operational life. Therefore, CK45 can be a suitable alternative in steel...

Trace metals analysis in molybdenite mineral sample

International Nuclear Information System (INIS)

Tamrakar, Praveen Kumar; Pitre, K.S.

2000-01-01

DC polarography and other related techniques, viz., DPP and DPASV have been successfully used for the simultaneous determination of trace metals in molybdenite mineral sample. The polarograms and voltammograms of sample solution have been recorded in 0.1 M (NH 4 ) 2 tartrate supporting electrolyte at two different pH values i.e., 2.7±0.1 and 9.0±0.1. The results indicate the presence of Cu 2+ , Mo 6+ , Cd 2+ , Ni 2+ , In 3+ , Fe 3+ and W 6+ metal ions in the sample. For the determination of tungsten(VI), 11 M HCl has been used as supporting electrolyte. Tungsten(VI) produces a well defined wave/peak with E 1/2 /Ep=-0.42V/-0.48V vs SCE in 11 M HCl. The quantitative analysis by the method of standard addition shows the mineral sample to have the following composition, Cu 2+ ( 14.83), Mo 6+ (253.70), Cd 2+ (41.36), Ni 2+ (16.08), In 3+ (3.06), Fe 3+ (83.00)and W 6+ (4.14 )mg/g of the sample. Statistical treatment of the observed voltammetric data reveals high accuracy and good precision of determination. The observed voltammetric results are comparable with those obtained using AAS method. (author)

Synchrotron X-ray Investigations of Mineral-Microbe-Metal Interactions

International Nuclear Information System (INIS)

Kemner, Kenneth M.; O'Loughlin, Edward J.; Kelly, Shelly D.; Boyanov, Maxim I.

2005-01-01

Interactions between microbes and minerals can play an important role in metal transformations (i.e. changes to an element's valence state, coordination chemistry, or both), which can ultimately affect that element's mobility. Mineralogy affects microbial metabolism and ecology in a system; microbes, in turn, can affect the system's mineralogy. Increasingly, synchrotron-based X-ray experiments are in routine use for determining an element's valence state and coordination chemistry, as well as for examining the role of microbes in metal transformations.

Assessment and Seasonal Variations of Heavy Metals and Mineral ...

African Journals Online (AJOL)

Mal Raji

ISSN 0794-5698. Assessment and Seasonal Variations of Heavy Metals and Mineral Elements in River ... immediately from Sokoto Cement Factory) at value above WHO's permissible limit in the rainy season. Ag .... level which is considered to represent a threat to the life of .... regulations governing waste management and.

Niger Republic Mineral Planning : Part IV - first volume : Main mineral substances specific study and their geological context

International Nuclear Information System (INIS)

Franconi, Antoine; Joo', Julien; Zibo, Idde

1981-01-01

This volume contains the detailed study of mineral substances industrially exploited to date : uranium, coal, non metallic building materials and public activities, and non conventionally exploited substances, that are : tin, columbite-tantalite, tungsten, gold, phosphates and evaporates [fr

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. Copyright © 2014 Elsevier B.V. All rights reserved.

tectonic environments and rare metal mineralization in pegmatites of ...

African Journals Online (AJOL)

Admin

The discrimination diagrams: Rb versus Nb +Y and Nb versus Y, and Th/Ta ratio combined with field observations and empirical information from the literature were used to infer the tectonic environments and sources of the rare metal mineralization in the pegmatites of Komu area, southwestern Nigeria. The discrimination ...

Metal immobilization by sludge-derived biochar: roles of mineral oxides and carbonized organic compartment.

Science.gov (United States)

Zhang, Weihua; Huang, Xinchen; Jia, Yanming; Rees, Frederic; Tsang, Daniel C W; Qiu, Rongliang; Wang, Hong

2017-04-01

Pyrolyzing sludge into biochar is a potentially promising recycling/disposal solution for municipal wastewater sludge, and the sludge-derived biochar (SDBC) presents an excellent sorbent for metal immobilization. As SDBC is composed of both mineral oxides and carbonized organic compartment, this study therefore compared the sorption behaviour of Pb and Zn on SDBC to those of individual and mixture of activated carbon (AC) and amorphous aluminium oxide (Al 2 O 3 ). Batch experiments were conducted at 25 and 45 °C, and the metal-loaded sorbents were artificially aged in the atmosphere for 1-60 days followed by additional sorption experiments. The Pb sorption was generally higher than Zn sorption, and the co-presence of Pb reduced Zn sorption on each studied sorbent. Higher sorption capacities were observed at 45 °C than 25 °C for SDBC and AC, while the opposite was shown for Al 2 O 3 , indicating the significance of temperature-dependent diffusion processes in SDBC and AC. Nevertheless, metal sorption was more selective on Al 2 O 3 that showed a greater affinity towards Pb over Zn under competition, correlating with the reducible fraction of sequential extraction. Furthermore, significant amounts of Pb and Zn were additionally sorbed on SDBC following 30-day ageing. The X-ray diffraction revealed the formation of metal-phosphate precipitates, while the X-ray photoelectron spectroscopy showed a larger quantity of metal-oxygen bonding after 30-day ageing of metal-loaded SDBC. The results may imply favourable long-term transformation and additional sorption capacity of SDBC. In conclusion, SDBC resembles the sorption characteristics of both organic and mineral sorbents in different aspects, presenting an appropriate material for metal immobilization during soil amendment.

Formation of secondary minerals in a lysimeter approach - A mineral-microbe interaction

Science.gov (United States)

Schäffner, F.; Merten, D.; De Giudici, G.; Beyer, A.; Akob, D. M.; Ricci, P. C.; Küsel, K.; Büchel, G.

2012-04-01

Heavy metal contamination of large areas due to uranium mining operations poses a serious long-term environmental problem. In the Ronneburg district (eastern Thuringia, Germany), leaching of low grade uranium bearing ores (uranium content metals, especially Cd, Ni, Co, Cu and Zn due to a residual contamination even after remediation efforts. To reveal the processes of secondary mineral precipitation in the field a laboratory lysimeter approach was set up under in situ-like conditions. Homogenized soil from the field site and pure quartz sand were used as substrates. In general, in situ measurements of redox potentials in the substrates showed highly oxidizing conditions (200-750 mV). Water was supplied to the lysimeter from below via a mariottés bottle containing contaminated groundwater from the field. Evaporation processes were allowed, providing a continuous flow of water. This led to precipitation of epsomite and probably aplowite on the top layer of substrate, similar to what is observed in field investigations. After 4 weeks, the first iron and manganese bearing secondary minerals became visible. Soil water samples were used to monitor the behaviour of metals within the lysimeter. Saturation indices (SI) for different secondary minerals were calculated with PHREEQC. The SI of goethite showed oversaturation with respect to the soil solution. SEM-EDX analyses and IR spectroscopy confirmed the formation of goethite. Geochemical data revealed that goethite formation was mainly dominated by Eh/pH processes and that heavy metals, e.g. Zn and U, could be enriched in this phase. Although Eh/pH data does not support formation of manganese minerals, Mn(II)-oxidizing bacteria (MOB) could be isolated from field soil samples, supporting the fact that microorganisms may influence this natural attenuation process. Laser ablation ICP-MS data reveal accumulation of manganese in MOB biomass on Mn(II)-containing agar plates. Furthermore, it was possible to show the importance

Effects of aerobic and anaerobic biological processes on leaching of heavy metals from soil amended with sewage sludge compost.

Science.gov (United States)

Fang, Wen; Wei, Yonghong; Liu, Jianguo; Kosson, David S; van der Sloot, Hans A; Zhang, Peng

2016-12-01

The risk from leaching of heavy metals is a major factor hindering land application of sewage sludge compost (SSC). Understanding the change in heavy metal leaching resulting from soil biological processes provides important information for assessing long-term behavior of heavy metals in the compost amended soil. In this paper, 180days aerobic incubation and 240days anaerobic incubation were conducted to investigate the effects of the aerobic and anaerobic biological processes on heavy metal leaching from soil amended with SSC, combined with chemical speciation modeling. Results showed that leaching concentrations of heavy metals at natural pH were similar before and after biological process. However, the major processes controlling heavy metals were influenced by the decrease of DOC with organic matter mineralization during biological processes. Mineralization of organic matter lowered the contribution of DOC-complexation to Ni and Zn leaching. Besides, the reducing condition produced by biological processes, particularly by the anaerobic biological process, resulted in the loss of sorption sites for As on Fe hydroxide, which increased the potential risk of As release at alkaline pH. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biodegradation of CuTETA, an effluent by-product in mineral processing.

Science.gov (United States)

Cushing, Alexander M L; Kelebek, Sadan; Yue, Siqing; Ramsay, Juliana A

2018-04-13

Polyamines such as triethylenetetramine (TETA) and other amine chelators are used in mineral processing applications. Formation of heavy metal complexes of these reagents as a by-product in effluent water is a recent environmental concern. In this study, Paecilomyces sp. was enriched from soil on TETA as the sole source of carbon and nitrogen and was found to degrade > 96 and 90% CuTETA complexes at initial concentrations of 0.32 and 0.79 mM respectively, following 96-h incubation. After destabilization, most of the copper (> 78%) was complexed extracellularly and the rest was associated with the cell. Mass spectroscopy results provided confirmation that copper re-complexed with small, extracellular, and organic molecules. There are no reports in the literature that Paecilomyces or any other organism can grow on TETA or CuTETA. This study is the first to show that biological destabilization of CuTETA complexes in mineral processing effluents is feasible.

Niger Republic Mineral Planning : Part IV - first volume : Main mineral substances specific study and their geological context; Plan Mineral de la Republique du Niger : Tome IV - 1er volume : Etude specifique des principales substances minerals et leur contexte geologique

Energy Technology Data Exchange (ETDEWEB)

Franconi, Antoine; Joo' , Julien; Zibo, Idde

1981-07-01

This volume contains the detailed study of mineral substances industrially exploited to date : uranium, coal, non metallic building materials and public activities, and non conventionally exploited substances, that are : tin, columbite-tantalite, tungsten, gold, phosphates and evaporates. [French] Ce volume contient l'etude detaillee des substances minerals exploitees industriellement a ce jour : l'uranium, le charbon, les materiaux non metalliques de construction et de travaux publics et les substances exploitees artisanalement qui sont : l'etain, la Colombo-tantalite, le tungstene, l'or, les phosphates et les evaporates.

TUCS/phosphate mineralization of actinides

Energy Technology Data Exchange (ETDEWEB)

Nash, K.L. [Argonne National Lab., IL (United States)

1997-10-01

This program has as its objective the development of a new technology that combines cation exchange and mineralization to reduce the concentration of heavy metals (in particular actinides) in groundwaters. The treatment regimen must be compatible with the groundwater and soil, potentially using groundwater/soil components to aid in the immobilization process. The delivery system (probably a water-soluble chelating agent) should first concentrate the radionuclides then release the precipitating anion, which forms thermodynamically stable mineral phases, either with the target metal ions alone or in combination with matrix cations. This approach should generate thermodynamically stable mineral phases resistant to weathering. The chelating agent should decompose spontaneously with time, release the mineralizing agent, and leave a residue that does not interfere with mineral formation. For the actinides, the ideal compound probably will release phosphate, as actinide phosphate mineral phases are among the least soluble species for these metals. The most promising means of delivering the precipitant would be to use a water-soluble, hydrolytically unstable complexant that functions in the initial stages as a cation exchanger to concentrate the metal ions. As it decomposes, the chelating agent releases phosphate to foster formation of crystalline mineral phases. Because it involves only the application of inexpensive reagents, the method of phosphate mineralization promises to be an economical alternative for in situ immobilization of radionuclides (actinides in particular). The method relies on the inherent (thermodynamic) stability of actinide mineral phases.

Radiotracer techniques in mineral processing

International Nuclear Information System (INIS)

Przewlocki, K.

1991-01-01

The value of the smelter metal content in currently exploited polymetallic ores mostly does not exceed 2%. Before metallurgical treatment, ore must pass through the concentration process. The benefication process usually starts from the comminution of excavated material and terminates at the flotation and drying of the concentrate. These operations consume vast quantities of energy. To be economically justified, the process requires optimization and, if possible, automatic control. Radioactive tracers were found to be useful in the identification of particular technological subsystems and their subsequent optimization. A great deal of experience has been gathered in this field so far. The industrial radiotracer test (RTT) is carried out using very sensitive multidetector recording systems which have digital data acquisition capabilities. The optimization strategy consists of periodically adjusting technological process and set points of controlled variables according to certain improvement procedures. If computer facilities are available, data interpretation and calibration of the mathematical models describing the technical process itself can be performed on the spot. This significantly accelerates the whole procedure as RTT may be repeated for particular system configurations. The procedure of plant optimization by means of RTT is illustrated in the paper using the example of the copper ore enrichment process, assuming that it is representative of the whole mineral industry. Identification by RTT of the three main operations involved in the ore enrichment process, such as comminution, flotation and granular classification, is discussed in detail as particular case studies. In reference to this, it is also shown how the technological process can be adjusted to be most efficient. (author). 14 refs, 7 figs

Current knowledge of US metal and nonmetal miner health: Current and potential data sources for analysis of miner health status

Science.gov (United States)

Yeoman, K. M.; Halldin, C. N.; Wood, J.; Storey, E.; Johns, D.; Laney, A. S.

2016-01-01

ABSTRACT Little is known about the current health status of US metal and nonmetal (MNM) miners, in part because no health surveillance systems exist for this population. The National Institute for Occupational Safety and Health (NIOSH) is developing a program to characterize burden of disease among MNM miners. This report discusses current knowledge and potential data sources of MNM miner health. Recent national surveys were analyzed, and literature specific to MNM miner health status was reviewed. No robust estimates of disease prevalence were identified, and national surveys did not provide information specific to MNM miners. Because substantial gaps exist in the understanding of MNM miners' current health status, NIOSH plans to develop a health surveillance program for this population to guide intervention efforts to reduce occupational and personal risks for chronic illness. PMID:25658684

Principles of image processing in machine vision systems for the color analysis of minerals

Science.gov (United States)

Petukhova, Daria B.; Gorbunova, Elena V.; Chertov, Aleksandr N.; Korotaev, Valery V.

2014-09-01

At the moment color sorting method is one of promising methods of mineral raw materials enrichment. This method is based on registration of color differences between images of analyzed objects. As is generally known the problem with delimitation of close color tints when sorting low-contrast minerals is one of the main disadvantages of color sorting method. It is can be related with wrong choice of a color model and incomplete image processing in machine vision system for realizing color sorting algorithm. Another problem is a necessity of image processing features reconfiguration when changing the type of analyzed minerals. This is due to the fact that optical properties of mineral samples vary from one mineral deposit to another. Therefore searching for values of image processing features is non-trivial task. And this task doesn't always have an acceptable solution. In addition there are no uniform guidelines for determining criteria of mineral samples separation. It is assumed that the process of image processing features reconfiguration had to be made by machine learning. But in practice it's carried out by adjusting the operating parameters which are satisfactory for one specific enrichment task. This approach usually leads to the fact that machine vision system unable to estimate rapidly the concentration rate of analyzed mineral ore by using color sorting method. This paper presents the results of research aimed at addressing mentioned shortcomings in image processing organization for machine vision systems which are used to color sorting of mineral samples. The principles of color analysis for low-contrast minerals by using machine vision systems are also studied. In addition, a special processing algorithm for color images of mineral samples is developed. Mentioned algorithm allows you to determine automatically the criteria of mineral samples separation based on an analysis of representative mineral samples. Experimental studies of the proposed algorithm

Progress in bioleaching: part B: applications of microbial processes by the minerals industries.

Science.gov (United States)

Brierley, Corale L; Brierley, James A

2013-09-01

This review presents developments and applications in bioleaching and mineral biooxidation since publication of a previous mini review in 2003 (Olson et al. Appl Microbiol Biotechnol 63:249-257, 2003). There have been discoveries of newly identified acidophilic microorganisms that have unique characteristics for effective bioleaching of sulfidic ores and concentrates. Progress has been made in understanding and developing bioleaching of copper from primary copper sulfide minerals, chalcopyrite, covellite, and enargite. These developments point to low oxidation-reduction potential in concert with thermophilic bacteria and archaea as a potential key to the leaching of these minerals. On the commercial front, heap bioleaching of nickel has been commissioned, and the mineral biooxidation pretreatment of sulfidic-refractory gold concentrates is increasingly used on a global scale to enhance precious metal recovery. New and larger stirred-tank reactors have been constructed since the 2003 review article. One biooxidation-heap process for pretreatment of sulfidic-refractory gold ores was also commercialized. A novel reductive approach to bioleaching nickel laterite minerals has been proposed.

Microbial Mineral Transformations at the Fe(II)/Fe(III) Redox Boundary for Solid Phase Capture of Strontium and Other Metal/Radionuclide Contaminants

International Nuclear Information System (INIS)

Ferris, F.G.; Roden, E.E.

2000-01-01

The migration of 90 Sr in groundwater is a significant environmental concern at former nuclear weapons production sites in the US and abroad. Although retardation of 90 Sr transport relative to mean groundwater velocity is known to occur in contaminated aquifers, Sr 2+ does not sorb as strongly to iron oxides and other mineral phases as do other metal-radionuclides contaminants. Thus, some potential exists for extensive 90 Sr migration from sources of contamination. Chemical or biological processes capable of retarding or immobilizing Sr 2+ in groundwater environments are of interest from the standpoint of understanding controls on subsurface Sr 2+ migration. In addition, it may be possible to exploit such processes for remediation of subsurface Sr contamination. In this study the authors examined the potential for the solid phase sorption and incorporation of Sr 2+ into carbonate minerals formed during microbial Fe(III) oxide reduction as a first step toward evaluating whether this process could be used to promote retardation of 90 Sr migrations in anaerobic subsurface environments. The demonstration of Sr 2+ capture in carbonate mineral phases formed during bacterial HFO reduction and urea hydrolysis suggests that microbial carbonate mineral formation could contribute to Sr 2+ retardation in groundwater environments. This process may also provide a mechanism for subsurface remediation of Sr 2+ and other divalent metal contaminants that form insoluble carbonate precipitates

Professional illnesses in miners caused by heavy metals and toxic substances

OpenAIRE

Veličkova N.; Petrova B.

2013-01-01

The exposure of humans in an environment contaminated with heavy metals is associated with many diseases, characterized by pathological changes in the respiratory tract, lung function deterioration. The results of the research, conducted with miners working in the “Sasa” lead and zinc mine, were focused on validating the existing professional risk. Most affected are the miners engaged in drilling head and ore. Disease was verified by analysis of acute symptoms. According to the time of ...

Chalcopyrite—bearer of a precious, non-precious metal

Science.gov (United States)

Kimball, Bryn E.

2013-01-01

The mineral chalcopyrite (CuFeS2) is the world's most abundant source of copper, a metal component in virtually every piece of electrical equipment. It is the main copper mineral in several different ore deposit types, the most important of which are porphyry deposits. Chalcopyrite is unstable at the Earth's surface, so it weathers from sulphide outcrops and mine waste piles, contributing acid and dissolved copper to what is known as acid rock drainage. If not prevented, dissolved copper from chalcopyrite weathering will be transported downstream, potentially harming ecosystems along the way. Pristine areas are becoming targets for future copper supply as we strive to meet ever-increasing demands for copper by developed and developing nations. Additionally, our uses for copper are expanding to include technology such as solar energy production. This has lead to the processing of increasingly lower grade ores, which is possible, in part, due to advances in bio-leaching (i.e. metal extraction catalysed by micro-organisms). Although copper is plentiful, it is still a nonrenewable resource. Future copper supply promises to fall short of demand and the volatility of the copper market may continue if we do not prioritize copper use and improve copper recycling and ore extraction efficiency.

Sorption Energy Maps of Clay Mineral Surfaces

International Nuclear Information System (INIS)

Cygan, Randall T.; Kirkpatrick, R. James

1999-01-01

A molecular-level understanding of mineral-water interactions is critical for the evaluation and prediction of the sorption properties of clay minerals that may be used in various chemical and radioactive waste disposal methods. Molecular models of metal sorption incorporate empirical energy force fields, based on molecular orbital calculations and spectroscopic data, that account for Coulombic, van der Waals attractive, and short-range repulsive energies. The summation of the non-bonded energy terms at equally-spaced grid points surrounding a mineral substrate provides a three dimensional potential energy grid. The energy map can be used to determine the optimal sorption sites of metal ions on the exposed surfaces of the mineral. By using this approach, we have evaluated the crystallographic and compositional control of metal sorption on the surfaces of kaolinite and illite. Estimates of the relative sorption energy and most stable sorption sites are derived based on a rigid ion approximation

Buckminsterfullerenes: a non-metal system for nitrogen fixation.

Science.gov (United States)

Nishibayashi, Yoshiaki; Saito, Makoto; Uemura, Sakae; Takekuma, Shin-Ichi; Takekuma, Hideko; Yoshida, Zen-Ichi

2004-03-18

In all nitrogen-fixation processes known so far--including the industrial Haber-Bosch process, biological fixation by nitrogenase enzymes and previously described homogeneous synthetic systems--the direct transformation of the stable, inert dinitrogen molecule (N2) into ammonia (NH3) relies on the powerful redox properties of metals. Here we show that nitrogen fixation can also be achieved by using a non-metallic buckminsterfullerene (C60) molecule, in the form of a water-soluble C60:gamma-cyclodextrin (1:2) complex, and light under nitrogen at atmospheric pressure. This metal-free system efficiently fixes nitrogen under mild conditions by making use of the redox properties of the fullerene derivative.

The mineralization and mechanism of the endogenetic mineral deposit in China

International Nuclear Information System (INIS)

Jiang Yonghong

2010-01-01

In the process of mineralization, due to the difference in rank, scale and order of structures orebody, mine colomn or rich ore bag are often produced in the specific structural parts. Obviously, it is controlled by favourite structure. The important and direct control of the structure to metal endogenetic mineralization evolution are representative on the affect of pulse action of structure to the multi-stage of mineralization evolution. According to the formation environment of the mineralization, it can be classified as collision orogeny mineralization, release(extension)mineralization, slide draw-division basin mineralization and shear zone extension mineralization. Throng the discuss of endogenetic deposit in the geological evolution, structure and formation machenism, the metallogenic model was preliminary established,and the criteria for delineating favourable metallogenic area was identified. (authors)

Stepwise effects of the BCR sequential chemical extraction procedure on dissolution and metal release from common ferromagnesian clay minerals: A combined solution chemistry and X-ray powder diffraction study

Energy Technology Data Exchange (ETDEWEB)

Ryan, P.C. [Geology Department, Middlebury College, Middlebury, Vermont 05753 (United States)], E-mail: pryan@middlebury.edu; Hillier, S. [Macaulay Institute, Aberdeen, AB15 8QH UK (United Kingdom); Wall, A.J. [Department of Geosciences, Penn State University, University Park, Pennsylvania, 16802 (United States)

2008-12-15

Sequential extraction procedures (SEPs) are commonly used to determine speciation of trace metals in soils and sediments. However, the non-selectivity of reagents for targeted phases has remained a lingering concern. Furthermore, potentially reactive phases such as phyllosilicate clay minerals often contain trace metals in structural sites, and their reactivity has not been quantified. Accordingly, the objective of this study is to analyze the behavior of trace metal-bearing clay minerals exposed to the revised BCR 3-step plus aqua regia SEP. Mineral quantification based on stoichiometric analysis and quantitative powder X-ray diffraction (XRD) documents progressive dissolution of chlorite (CCa-2 ripidolite) and two varieties of smectite (SapCa-2 saponite and SWa-1 nontronite) during steps 1-3 of the BCR procedure. In total, 8 ({+-} 1) % of ripidolite, 19 ({+-} 1) % of saponite, and 19 ({+-} 3) % of nontronite (% mineral mass) dissolved during extractions assumed by many researchers to release trace metals from exchange sites, carbonates, hydroxides, sulfides and organic matter. For all three reference clays, release of Ni into solution is correlated with clay dissolution. Hydrolysis of relatively weak Mg-O bonds (362 kJ/mol) during all stages, reduction of Fe(III) during hydroxylamine hydrochloride extraction and oxidation of Fe(II) during hydrogen peroxide extraction are the main reasons for clay mineral dissolution. These findings underscore the need for precise mineral quantification when using SEPs to understand the origin/partitioning of trace metals with solid phases.

Mineralization of alanine enantiomers in soil treated with heavy metals and nutrients

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Pavel Formánek

2011-01-01

Full Text Available This work deals with the determination of the effect of heavy metals and nutrients applied to the soil on alanine enatiomers mineralization with the main focus on evaluating the effect on L/D alanine respiration rate ratio. This study was initiated because previous research works revealed a change in L/D amino acid respiration under acid- or heavy metal-stress in soil. Generally, D-amino acids artificially supplied to soil are less utilized by microorganisms compared with their L-enantiomers. Stress of soil microorganisms cause decreased discrimination of D-amino acids utilization. Also, previous research showed that an application of fertilizers or combinations of fertilizers may affect the mineralization rate of L-amino acids differently, compared with their D-enantiomers. The results of this study show, that the effect of both heavy metals and nutrients on the L/D ratio was not clear, increasing or decreasing this ratio. Further research is necessary to broaden this study.

Analyses of heavy metals in mineral trioxide aggregate and Portland cement.

Science.gov (United States)

Schembri, Matthew; Peplow, George; Camilleri, Josette

2010-07-01

Portland cement is used in the construction industry as a binder in concrete. It is manufactured from chalk, limestone, and clay, which are clinkered at very high temperatures and ground with gypsum to form Portland cement. The raw materials and the manufacturing process can result in the inclusion of heavy metals in Portland cement. Portland cement with a four to one addition of bismuth oxide is marketed as mineral trioxide aggregate (MTA), which is used mainly as a dental material. Heavy metal inclusion can be of concern because MTA is in contact with hard and soft tissues. Measurements of arsenic, lead, and chromium in hydrated gray and white Portland cement, ProRoot MTA, and MTA Angelus were conducted with graphite furnace atomic absorption spectrophotometry after acid digestion on the hydrated material. The leaching of the metal ions from the solid material in water and simulated body fluid (SBF) was also determined. All cement types showed high relative values of leached chromium compared with arsenic and lead in both the total metal content and leached species. The gray Portland cement showed the highest total amount of metal. The white Portland and both MTAs had lower values for all the leached metal ions. Both MTAs released more arsenic than the amount specified in ISO 9917-1 (2007). Portland cements and MTAs showed evidence of heavy metals in the acid-soluble form as well as leaching in deionized water and SBF. MTA contained levels of arsenic higher than the safe limit specified by the ISO 9917-1 (2007). Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Hydrogeochemical processes governing the origin, transport and fate of major and trace elements from mine wastes and mineralized rock to surface waters

Science.gov (United States)

Nordstrom, D. Kirk

2011-01-01

The formation of acid mine drainage from metals extraction or natural acid rock drainage and its mixing with surface waters is a complex process that depends on petrology and mineralogy, structural geology, geomorphology, surface-water hydrology, hydrogeology, climatology, microbiology, chemistry, and mining and mineral processing history. The concentrations of metals, metalloids, acidity, alkalinity, Cl-, F- and SO42- found in receiving streams, rivers, and lakes are affected by all of these factors and their interactions. Remediation of mine sites is an engineering concern but to design a remediation plan without understanding the hydrogeochemical processes of contaminant mobilization can lead to ineffective and excessively costly remediation. Furthermore, remediation needs a goal commensurate with natural background conditions rather than water-quality standards that might bear little relation to conditions of a highly mineralized terrain. This paper reviews hydrogeochemical generalizations, primarily from US Geological Survey research, that enhance our understanding of the origin, transport, and fate of contaminants released from mined and mineralized areas.

Energy consumption analysis of Spanish food and drink, textile, chemical and non-metallic mineral products sectors

International Nuclear Information System (INIS)

Aranda-Usón, Alfonso; Ferreira, Germán; Mainar-Toledo, M.D.; Scarpellini, Sabina; Llera Sastresa, Eva

2012-01-01

This paper provides quantitative information for energy consumption from four different industry sectors based on an energy analysis obtained by means of in-situ energy audits and complementary information. The latter information was taken from Saving Strategy and Energy Efficiency in Spain (Estrategia de Ahorro y Eficiencia Energética en España 2004–2010, E4) documents and the 2009 Industrial Survey of Spain from the National Statistics Institute (Instituto Nacional de Estadística, INE). The results show an estimate of energy consumption for each sector, namely Spanish food, drink and tobacco (9.6%), textile (4.5%), chemical (14.7%), and non-metallic mineral products (24.3%), as well as the degree of inefficiency for each, obtained by means of a stochastic frontier production function model. These results are combined with the energy consumption analysis to identify potential energy saving opportunities around 20.0% of the total energy consumption for all studied sectors. These energy saving opportunities are classified according to thermal or electrical energy consumption and percentage savings of the total energy consumption. -- Highlights: ► This study presents the analysis of four Spanish energy-consuming industrial sectors. ► The four selected sectors account for 33.0% of the total industrial SMEs. ► An audit was carried out in several factories from each analysed industrial sector. ► Stochastic Cobb-Douglas frontiers were used to estimate production frontiers. ► Potential energy saving opportunities around 20.0% of the total energy consumption.

A case in support of implementing innovative bio-processes in the metal mining industry.

Science.gov (United States)

Sánchez-Andrea, Irene; Stams, Alfons J M; Weijma, Jan; Gonzalez Contreras, Paula; Dijkman, Henk; Rozendal, Rene A; Johnson, D Barrie

2016-06-01

The metal mining industry faces many large challenges in future years, among which is the increasing need to process low-grade ores as accessible higher grade ores become depleted. This is against a backdrop of increasing global demands for base and precious metals, and rare earth elements. Typically about 99% of solid material hauled to, and ground at, the land surface currently ends up as waste (rock dumps and mineral tailings). Exposure of these to air and water frequently leads to the formation of acidic, metal-contaminated run-off waters, referred to as acid mine drainage, which constitutes a severe threat to the environment. Formation of acid drainage is a natural phenomenon involving various species of lithotrophic (literally 'rock-eating') bacteria and archaea, which oxidize reduced forms of iron and/or sulfur. However, other microorganisms that reduce inorganic sulfur compounds can essentially reverse this process. These microorganisms can be applied on industrial scale to precipitate metals from industrial mineral leachates and acid mine drainage streams, resulting in a net improvement in metal recovery, while minimizing the amounts of leachable metals to the tailings storage dams. Here, we advocate that more extensive exploitation of microorganisms in metal mining operations could be an important way to green up the industry, reducing environmental risks and improving the efficiency and the economy of metal recovery. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Soil Organic Matter Stabilization via Mineral Interactions in Forest Soils with Varying Saturation Frequency

Science.gov (United States)

Possinger, A. R.; Inagaki, T.; Bailey, S. W.; Kogel-Knabner, I.; Lehmann, J.

2017-12-01

Soil carbon (C) interaction with minerals and metals through surface adsorption and co-precipitation processes is important for soil organic C (SOC) stabilization. Co-precipitation (i.e., the incorporation of C as an "impurity" in metal precipitates as they form) may increase the potential quantity of mineral-associated C per unit mineral surface compared to surface adsorption: a potentially important and as yet unaccounted for mechanism of C stabilization in soil. However, chemical, physical, and biological characterization of co-precipitated SOM as such in natural soils is limited, and the relative persistence of co-precipitated C is unknown, particularly under dynamic environmental conditions. To better understand the relationships between SOM stabilization via organometallic co-precipitation and environmental variables, this study compares mineral-SOM characteristics across a forest soil (Spodosol) hydrological gradient with expected differences in co-precipitation of SOM with iron (Fe) and aluminum (Al) due to variable saturation frequency. Soils were collected from a steep, well-drained forest soil transect with low, medium, and high frequency of water table intrusion into surface soils (Hubbard Brook Experimental Forest, Woodstock, NH). Lower saturation frequency soils generally had higher C content, C/Fe, C/Al, and other indicators of co-precipitation interactions resulting from SOM complexation, transport, and precipitation, an important process of Spodosol formation. Preliminary Fe X-ray Absorption Spectroscopic (XAS) characterization of SOM and metal chemistry in low frequency profiles suggest co-precipitation of SOM in the fine fraction (soils showed greater SOC mineralization per unit soil C for low saturation frequency (i.e., higher co-precipitation) soils; however, increased mineralization may be attributed to non-mineral associated fractions of SOM. Further work to identify the component of SOM contributing to rapid mineralization using 13C

SOLVENT EXTRACTION PROCESS FOR SEPARATING ACTINIDE AND LANTHANIDE METAL VALUES

Science.gov (United States)

Hildebrandt, R.A.; Hyman, H.H.; Vogler, S.

1962-08-14

A process of countercurrently extracting an aqueous mineral acid feed solution for the separation of actinides from lanthanides dissolved therern is described. The feed solution is made acid-defrcient with alkali metal hydroxide prior to.contact with acid extractant; during extraction, however, acid is transferred from organic to aqueous solution and the aqueous solution gradually becomes acid. The acid-deficient phase ' of the process promotes the extraction of the actinides, while the latter acid phase'' of the process improves retention of the lanthanides in the aqueous solution. This provides for an improved separation. (AEC)

Novel non-platinum metal catalyst material

DEFF Research Database (Denmark)

2014-01-01

The present invention relates to a novel non-platinum metal catalyst material for use in low temperature fuel cells and electrolysers and to fuel cells and electrolysers comprising the novel non-platinum metal catalyst material. The present invention also relates to a novel method for synthesizing...... the novel non-platinum metal catalyst material....

Radiation damage in non-metals

International Nuclear Information System (INIS)

Stoneham, A.M.

1980-01-01

Work on the problem of radiation damage in non-metals over the past 25 years is reviewed with especial emphasis on the contribution made at AERE, Harwell and in particular by members of the Theoretical Physics Division. In the years between 1954 and the end of the 1960's the main thrust in the radiation damage of non-metals was model-building including devising defect models and mechanisms that were qualitatively acceptable, and compiling systematic data. The early 1970's made greater quantitative demands as computer techniques made theory more powerful. In many cases it was possible to predict defect properties accurately, so that one could distinguish between different defect models which were hard to tell apart by experiment alone. In the late 1970's the most important aspect has moved towards mechanisms of defect processes, especially in cases where experiment by itself is limited by timescale, by complexity, by the unintentional impurities inevitable in real crystals, or by the extreme conditions required. (UK)

Proceedings of the 41. annual meeting of the Canadian Mineral Processors : 2009

Energy Technology Data Exchange (ETDEWEB)

Orford, I. [AMEC, Oakville, ON (Canada); Henderson, R. [Kinross Gold Corp., Toronto, ON (Canada); Zinck, J. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Mining and Mineral Sciences Laboratories] (comps.)

2009-07-01

This conference provided a forum for the exchange of mineral processing information. It addressed a broad range of issues affecting the minerals and metals sector, with particular reference to advances in technology that continue to improve mineral processing. New, highly efficient mineral extraction processes were presented along with process analysis methods and advanced control systems. In addition to a plenary session, the conference featured the following 6 sessions: (1) flotation, (2) operations, (3) laboratory and pilot plants, (4) precious metals, (5) new ideas and technologies, and (6) comminution. The conference featured 38 presentations, of which 3 have been catalogued separately for inclusion in this database. refs., tabs., figs.

Mineralogy and mineral chemistry of rare-metal pegmatites at Abu Rusheid granitic gneisses, South Eastern Desert, Egypt

Directory of Open Access Journals (Sweden)

Mohamed Fahmy Raslan

2011-12-01

-site where it ranges from 12.72 to 16.49% with an average of 14.84%. The calculated formula of the studied fergusonite is A(Y0.303 ΣREE0.014 U0.135 Th0.063 Ca0.013 Pb0.006 Si0.213 Zr0.035 Hf0.048 Fe0.105Σ0.935 B(Nb0.61 Ta0.084 Ti0.01Σ0.704 O4.The presence of uraninite (high Th, and REE contents and thorite, indicates that these minerals magmatic processes and followed by hydrothermal processes which are responsible for the precipitation of Nb-Ta multioxide minerals. Uranophane and kasolite of Abu Rusheid pegmatites are most probably originated from hydrothermalalterations of the primary uraninite. Abu Rushied pegmatites are characterized by being of ZNF-type due to their marked enrichement in Zr, Nb, and F, with a typical geochemical signature: Zr, Nb >>Ta, LREE, Th, P, F. Accordingly, the mineralized Abu Rushied pegmatite can be considered as a promising target ore for its rare metal mineralization that includes mainly Nb, Ta, Y, U, and REE together with Zr, Hf, Sn and Th.

Preliminary Mineral Resource Assessment of Selected Mineral Deposit Types in Afghanistan

Science.gov (United States)

Ludington, Steve; Orris, Greta J.; Bolm, Karen S.; Peters, Stephen G.; ,

2007-01-01

INTRODUCTION Wise decision-making and management of natural resources depend upon credible and reliable scientific information about the occurrence, distribution, quantity and quality of a country's resource base. Economic development decisions by governments require such information to be part of a Mineral Resource Assessment. Such Mineral Assessments are also useful to private citizens and international investors, consultants, and companies prior to entry and investment in a country. Assessments can also be used to help evaluate the economic risks and impact on the natural environment associated with development of resources. In February 2002, at the request of the Department of State and the then U.S. Ambassador to Afghanistan (Robert P. Finn), the U.S. Geological Survey (USGS) prepared a detailed proposal addressing natural resources issues critical to the reconstruction of Afghanistan. The proposal was refined and updated in December 2003 and was presented as a 5-year work plan to USAID-Kabul in February 2004. USAID-Kabul currently funds this plan and this report presents a part of the preliminary results obligated for fiscal year 2006. A final Preliminary Assessment of the Non Fuel Mineral Resource of Afghanistan will be completed and delivered at the end of fiscal year 2007. Afghanistan has abundant metallic and non-metallic resources, but the potential resources have never been systematically assessed using modern methods. Much of the existing mineral information for Afghanistan was gathered during the 1950s and continued in the late 1980s until the departure of the geologic advisors from the Soviet Union. During this period, there were many mineral-related activities centered on systematic geologic mapping of the country, collection of geochemical and rock samples, implementation of airborne geophysical surveys, and exploration focused on the discovery of large mineral deposits. Many reports, maps, charts, and tables were produced at that time. Some of

The distribution of some rare metals in the process of separation of organic matter from Estonian dictyonema argillite

International Nuclear Information System (INIS)

Palvadre, R.; Ahelik, V.

1993-01-01

The distribution of rare metals Mo, U and V in the process of separation of organic matter from Maardu and Toolse argillite s is discussed. The beneficiation process of argillite consists of the hydro cycling treatment, in the course of which organic matter is separated as a light fraction, followed by direct flotation of organic matter and pyrite concentrates. Determinations of Mo and U were made by X-ray fluorescence, V by titration and pyrite by titration of iron. It can be concluded that rare metals Mo, U and V were concentrating in organic matter, their recovery in pyrite and quartz was negligible, depending on the degree of pyrite separation. The recovery of rare metals, especially that of V in the mineral phase, was more considerable in the processing of Maardu argillite, whose content of clay minerals was higher than that of Toolse argillite. 4 tabs., 6 refs

Microbial impact on metallic corrosion processes: case of iron reducing bacteria

International Nuclear Information System (INIS)

Esnault, Loic; Jullien, Michel; Libert, Marie; Mustin, Christian

2010-01-01

Document available in extended abstract form only. French concept of deep disposal of nuclear waste is based on a multi-barrier system with a metal container and a clayey host rock as last natural barrier for radionuclides confinement and to avoid their migration in the environment. One of the most important criteria for the safety assessment concerns the life time of metal containers. In this deep environment (elevated pressure and temperature, low water content) many factors may induce an alteration and modification of metal containers properties through corrosion processes. Two types of reactions are currently studied First, the anaerobic aqueous corrosion (a) which is depending on the amount of water available and the second is clayey corrosion (b) by an oxidation of structural Iron(III) or clay's H + on Fe(0) of metal containers. - Fe 0 + 2H 2 O → Fe 2+ + 2OH - + H 2 (a) - Fe 0 + 2H + argile → Fe 2+ solution + H 2 (b) - Fe 0 + Fe 3+ argile → Fe 2+ solution + Fe 2+ argile (b) These processes will entail different reaction products: first, we observe formation of corrosion products like aqueous Fe(II) and magnetite, hematite like mineral. These new minerals inhibit aqueous corrosion by the formation of a passivation process. For the second process, we observe a transformation of smectites into iron-rich serpentine-type minerals. These phenomenons will be responsible for a potential loss of confinement properties such as release of radionuclides, swelling and capacity to cations exchange. Moreover, since the discovery of microorganisms in deep clayey environment or in bentonite used as swelling clay. A new corrosion parameter 'biological one inducing bio-corrosion process' must be taken into account and has to be investigated to improve geochemical prediction on the sustainability of containers in geological disposal. - Impact of microorganisms has to be focused in term of bio-corrosion and more precisely on an indirect corrosion through the

A non-pedological hypothesis for the processes of uranium mineralization in calcrete

International Nuclear Information System (INIS)

Briot, P.; Fuchs, Y.

1984-01-01

The non-pedological hypothesis presented for the origin of the uraniferous calcrete deposits in Western Australia is based on the premise that alluvial and calcareous lacustrine sediments were initially formed during earlier wet periods, evidence for which has been found in the fossil records. These were followed by subsequent epigenetic alteration accompanied by the precipitation of uranium mineralization during drier semi-arid periods. Typical examples of the processes involved were found in the Yeelirrie uranium deposit. During the latter semi-arid period, the limited surface flow which consisted of periodic flash flood conditions probably contributed marginally to the recharge of the groundwater, and consequently, semi-stagnant groundwater conditions evolved, particularly where the hydraulic gradient was extremely small, for example, for the Yeelirrie channel it is approximately 0.001. In addition, ponding of water behind a natural barrier caused the groundwater to evolve along the following geochemical sequence: mild alkalinity, weak oxidizing conditions, and oversaturation in dissolved elements. These hydrological and hydrogeochemical conditions induced the epigenetic alteration of the palustral/lacustrine limestone, bringing about dolomite neogenesis and the precipitation of carnotite. The source of the uranium in the calcretes and the groundwater of the Yeelirrie channel is considered to be the weathered outcrops of the breakaways along its margins. The genetic hypothesis proposed in this paper, although somewhat different from those described previously and elsewhere in this volume, could be applied to the other uranium-bearing calcretes in Mauritania, Namibia, and Somalia

Mining Waste Classification and Quantity of Non-Metal Minesin Slovenia

Directory of Open Access Journals (Sweden)

Ana Burger

2007-06-01

Full Text Available Mining is an important human activity that creates wealth and supplies materials for maintaining standard of living and further human development. However, mining has also negative impacts on the environment and society. One of them is the production of mining waste throughout the entire mining cycle, in particular in the mine development and operation /production stage.Due to the EU Directive 2006/21/EC on the management of waste from the extractive industries and its implementation in Member state, estimation on quality and quantity of mining waste from active non-metal mines in Slovenia was carried out. In the selected mines mining and processing was closely examined. With material flow analysis quantity and characteristics of mining waste were defined for several mines of different commodities.Data on mining waste were afterwards generalized in order to get an overall country evaluation on mining waste “production” of non-metal mines.Mining waste as a result of mining and beneficiation processes in non-metal mines of Slovenia is either inert or non-hazardous. Most of the mining waste is used for mine reclamation running simultaneously with the production phase. The largest amounts of mining waste per unit produced are created in dimension stone industry. Since the dimensionstone production is small, the waste amount is negligible. Large quantities of mining waste are produced in crushed stone and, sand and gravel operations, because aggregate production is pretty large with regard to other non-metals production in Slovenia. We can therefore conclude that large quantities of mining waste from non-metal mines, which are mostly used in reclamation and for side products, do not represent danger to the environment.

Short-term variability of mineral dust, metals and carbon emission from road dust resuspension

Science.gov (United States)

Amato, Fulvio; Schaap, Martijn; Denier van der Gon, Hugo A. C.; Pandolfi, Marco; Alastuey, Andrés; Keuken, Menno; Querol, Xavier

2013-08-01

Particulate matter (PM) pollution in cities has severe impact on morbidity and mortality of their population. In these cities, road dust resuspension contributes largely to PM and airborne heavy metals concentrations. However, the short-term variation of emission through resuspension is not well described in the air quality models, hampering a reliable description of air pollution and related health effects. In this study we experimentally show that the emission strength of resuspension varies widely among road dust components/sources. Our results offer the first experimental evidence of different emission rates for mineral dust, heavy metals and carbon fractions due to traffic-induced resuspension. Also, the same component (or source) recovers differently in a road in Barcelona (Spain) and a road in Utrecht (The Netherlands). This finding has important implications on atmospheric pollution modelling, mostly for mineral dust, heavy metals and carbon species. After rain events, recoveries were generally faster in Barcelona rather than in Utrecht. The largest difference was found for the mineral dust (Al, Si, Ca). Tyre wear particles (organic carbon and zinc) recovered faster than other road dust particles in both cities. The source apportionment of road dust mass provides useful information for air quality management.

Modification of Non-Metallic Inclusions by Rare-Earth Elements in Microalloyed Steels

Directory of Open Access Journals (Sweden)

M. Opiela

2012-04-01

Full Text Available The modification of the chemical composition of non-metallic inclusions by rare-earth elements in the new-developed microalloyed steels was discussed in the paper. The investigated steels are assigned to production of forged elements by thermo- mechanical treatment. The steels were melted in a vaccum induction furnace and modification of non-metallic inclusions was carried out by the michmetal in the amount of 2.0 g per 1 kg of steel. It was found that using material charge of high purity and a realization of metallurgical process in vacuous conditions result in a low concentration of sulfur (0.004%, phosphorus (from 0.006 to 0.008% and oxygen (6 ppm. The high metallurgical purity is confirmed by a small fraction of non-metallic inclusions averaging 0.075%. A large majority of non-metallic inclusions are fine, globular oxide-sulfide or sulfide particles with a mean size 17m2. The chemical composition and morphology of non-metallic inclusions was modified by Ce, La and Nd, what results a small deformability of non- metallic inclusions during hot-working.

Comparing heavy metal contents in crops receiving mineral fertilisers and animal manure

DEFF Research Database (Denmark)

Christensen, Bent Tolstrup; Elsgaard, Lars

2014-01-01

Spring barley (grain, straw), grass-clover (two cuts), winter wheat (grain, straw) and silage maize grown in the Askov long-term experiment with different levels (0, ½, 1, 1½, 2) of mineral fertiliser (NPK) and animal manure (AM) had concentrations of As, Pb, Cd and Hg below the EC maximum permis...... of NPK and AM does not pose a threat in terms of feed quality. However, the long-term accumulation of heavy metals added with mineral fertilisers and animal manure is essentially irreversible and may threaten soil quality....... in the analysed metal contents between crops grown with NPK and AM. Crop contents of uranium and thallium were below the analytical detection limits regardless of nutrient source and addition rate. Thus in a farming context similar to that of the Askov experiment, the long-term application of standard rates...

Bacterial assimilation reduction of iron in the treatment of non-metallics

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Peter Malachovský

2005-11-01

Full Text Available Natural non-metallics, including granitoide and quartz sands, often contain iron which decreases the whiteness of these raw materials. Insoluble Fe3+ in these samples could be reduced to soluble Fe2+ by bacteria of Bacillus spp. and Saccharomyces spp. The leaching effect, observed by the measurement of Fe2+concentration in a solution, showed higher activities of a bacterial kind isolated from the Bajkal lake and also by using of yeast Saccharomyces sp. during bioleaching of quartz sands. However, allkinds of Bacillus spp. isolated from the Slovak deposit and from Bajkal lake were very active in the iron reduction during bioleaching of the feldspar raw material. This metal was efficiently removed from quartz sands as documented by the Fe2O3 decrease (from 0,317 % to 0,126 % and from feldpars raw materials by the Fe2O3 decrease (from 0,288 % to 0,115 % after bioleaching. The whiteness of these non-metallics was increased during a visual comparison of samples before and after bioleaching but samples contain selected magnetic particles. A removal of iron as well as a release of iron minerals from silicate matrix should increase the effect of the magnetic separation and should give a product which is suitable for industrial applications.

Understanding Contaminants Associated with Mineral Deposits

Science.gov (United States)

Verplanck, Philip L.

2008-01-01

Interdisciplinary studies by the U.S. Geological Survey (USGS) have resulted in substantial progress in understanding the processes that control *the release of metals and acidic water from inactive mines and mineralized areas, *the transport of metals and acidic water to streams, and *the fate and effect of metals and acidity on downstream ecosystems. The potential environmental effects associated with abandoned and inactive mines, resulting from the complex interaction of a variety of chemical and physical processes, is an area of study that is important to the USGS Mineral Resources Program. Understanding the processes contributing to the environmental effects of abandoned and inactive mines is also of interest to a wide range of stakeholders, including both those responsible for managing lands with historically mined areas and those responsible for anticipating environmental consequences of future mining operations. The recently completed (2007) USGS project entitled 'Process Studies of Contaminants Associated with Mineral Deposits' focused on abandoned and inactive mines and mineralized areas in the Rocky Mountains of Montana, Colorado, New Mexico, Utah, and Arizona, where there are thousands of abandoned mines. Results from these studies provide new information that advances our understanding of the physical and biogeochemical processes causing the mobilization, transport, reaction, and fate of potentially toxic elements (including aluminum, arsenic, cadmium, copper, iron, lead, and zinc) in mineralized near-surface systems and their effects on aquatic and riparian habitat. These interdisciplinary studies provide the basis for scientific decisionmaking and remedial action by local, State, and Federal agencies charged with minimizing the effects of potentially toxic elements on the environment. Current (2007) USGS research highlights the need to understand (1) the geologic sources of metals and acidity and the geochemical reactions that release them from their

Tracing low-temperature aqueous metal migration in mineralized watersheds with Cu isotope fractionation

International Nuclear Information System (INIS)

Mathur, R.; Munk, L.A.; Townley, B.; Gou, K.Y.; Gómez Miguélez, N.; Titley, S.; Chen, G.G.; Song, S.; Reich, M.; Tornos, F.; Ruiz, J.

2014-01-01

Highlights: • Cu isotope fractionation of ores and waters identifies copper sulfide weathering. • Redox reactions cause isotopic shift measured in areas of sulfide weathering. • Consistent isotope signature in different deposit, climate, or concentration. - Abstract: Copper isotope signatures in waters emanating from mineralized watersheds provide evidence for the source aqueous copper in solution. Low-temperature aqueous oxidation of Cu sulfide minerals produces significant copper isotopic fractionation between solutions and residues. Abiotic experimental data of fractionation (defined as Δ liquid–solid ‰ = δ 65 Cu liquid − δ 65 Cu solid ) are on the order of 1–3‰ and are unique for copper rich-sulfide minerals. Data presented here from ores and waters within defined boundaries of porphyry copper, massive sulfide, skarn, and epithermal ore deposits mimic abiotic experiments. Thus, the oxidation of sulfide minerals appears to cause the signatures in the waters although significant biological, temperature, and pH variations exist in the fluids. Regardless of the deposit type, water type, concentration of Cu in solution, or location, the data provide a means to trace sources of metals in solutions. This relationship allows for tracking sources and degree of metal migration in low temperature aqueous systems and has direct application to exploration geology and environmental geochemistry

Directions of development of research methods in the assessment of leaching of heavy metals from mineral waste

Directory of Open Access Journals (Sweden)

Król Anna

2016-01-01

Full Text Available There are many test methods to assess the level of the release of heavy metals into the environment from mineral waste materials. Leaching methods can be different depending on the leaching time periods, leaching dynamics, sample preparation method or the pH of the elution medium. In Poland, little attention is paid to the research on the relationship between the leaching of particular heavy metals from mineral wastes and changes in environmental conditions, including the pH of the environment. Tests being carried out abroad have started to pay great attention to the pH-dependent impact of the environment and the liquid being in contact with the material on the degree of leaching contaminants from wastes. The solubility of all metals depends on the value of the pH. Authors of the paper will try to prove that Polish methods of waste characterization is incomplete and inconsistent with opinions prevailing in the global literature. The procedure described in the Polish standards are insufficient to determine the actual level of leaching of heavy metals having regard to the impact of multiple external conditions on the level of leaching of heavy metals. Paper will present a directions of development of research methods in the assessment of leaching of heavy metals from mineral waste.

Hydrothermal Pb-Zn sulphide mineralization on the site Marianka (Small Carpathians); Hydrotermalna Pb-Zn sulfidicka mineralizacia na lokalite Marianka (Male Karpaty)

Energy Technology Data Exchange (ETDEWEB)

Kubac, A [Univerzita Komenskeho v Bratislave, Prirodovedecka fakulta, Katedra mineralogie a petrologie, 84215 Bratislava (Slovakia)

2012-04-25

Hydrothermal Pb-Zn sulphide mineralization at Marianka village in Small Carpathians occurs in Palaeozoic metapelit rocks of Tatricum crystalline. Mineralization consists of ore lenses. Banded texture of ores is typical. The main ore minerals are sphalerite and galenite accompanied by bournonit, boulangerit, meneghinit, pyrite, chalcopyrite, tetrahedrite, marcasite and pyrotite. Quartz is the main non-metallic mineral. Other non-metallic minerals are calcite, ankerite, siderite and dolomite. Micro-thermometric measurements of fluid inclusions in quartz indicate creation of mineralization probably from low salinic fluids (0.1 to 20 wt.% NaCl equiv.), at 100 to 150 grad C. (authors)

Protein-assisted synthesis of double-shelled CaCO3 microcapsules and their mineralization with heavy metal ions.

Science.gov (United States)

Li, Xuan Qi; Feng, Zhiwei; Xia, Yinyan; Zeng, Hua Chun

2012-02-13

Calcium carbonate (CaCO(3)) is one of the most abundant and important biominerals in nature. Due to its biocompatibility, biodegradability and nontoxicity, CaCO(3) has been investigated extensively in recent years for various fundamental properties and technological applications. Inspired by basic wall structures of cells, we report a protein-assisted approach to synthesize CaCO(3) into a double-shelled structural configuration. Due to varying reactivities of outer and inner shells, the CaCO(3) microcapsules exhibit different sorption capacities and various resultant structures toward different kinds of heavy metal ions, analogical to biologically controlled mineralization (BCM) processes. Surprisingly, three mineralization modes resembling those found in BCM were found with these bacterium-like "CaCO(3) cells". Our investigation of the cytotoxicity (MTT assay protocol) also indicates that the CaCO(3) microcapsules have almost no cytotoxicity against HepG2 cells, and they might be useful for future application of detoxifying heavy metal ions after further study. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The enhancing of Au-Ag-Te content in tellurium-bearing ore mineral by bio-oxidation-leaching

Science.gov (United States)

Kim, PyeongMan; Kim, HyunSoo; Myung, EunJi; Kim, YoonJung; Lee, YongBum; Park*, CheonYoung

2015-04-01

The purpose of this study is to enhance the content of valuable metals such as Au-Ag-Te in tellurium-bearing minerals by bio-oxidation-leaching. It was confirmed that pyrite, chalcopyrite, sphalerite and galena were produced together with tellurium-bearing minerals including hessite, sylvanite and tellurobismuthite from ore minerals and concentrates through microscopic observation and SEM/EDS analysis. In a bio-oxidation-leaching experiment, with regard to Au, Ag, Te, Cu and Fe, the changes in the amount of leaching and the content of leaching residues were compared and analyzed with each other depending on the adaptation of an indigenous microbe identified as Acidithiobacillus ferrooxidans. As a result of the experiment, the Au-Ag-Te content in tellurium-bearing ore mineral was enhanced in the order of physical oxidation leaching, physical/non-adaptive bio-oxidation-leaching and physical/adaptive biological leaching. It suggests that the bio-oxidation-leaching using microbes adapted in tellurium-bearing ore mineral can be used as a pre-treatment and a main process in a recovery process of valuable metals. "This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(NRF-2013R1A1A2004898)"

Book review: Economic geology: Principles and practice: Metals, minerals, coal and hydrocarbons—Introduction to formation and sustainable exploitation of mineral deposits

Science.gov (United States)

Anderson, Eric

2013-01-01

This volume, available in both hardcover and paperback, is an English translation of the fifth edition of the German language text Mineralische und Energie-Rohstoffe. The book provides an extensive overview of natural resources and societal issues associated with extracting raw materials. The comprehensive list of raw materials discussed includes metals, industrial minerals, coal, and hydrocarbons. The book is divided into four parts: (1) “Metalliferous ore deposits,” (2) “Nonmetallic minerals and rocks,” (3) “Practice of economic geology,” and (4) “Fossil energy raw materials—coal, oil, and gas.” These sections are bound by a brief introduction and an extensive list of up-to-date references as well as an index. Each chapter begins with a concise synopsis and concludes with a summary that contains useful suggestions for additional reading. All figures are grayscale images and line drawings; however, several have been grouped together and reproduced as color plates. Also included is a companion website (www.wiley.com/go/pohl/geology) that contains additional resources, such as digital copies of figures, tables, and an expanded index, all available for download in easy-to-use formats.Economic Geology: Principles and Practice: Metals, Minerals, Coal and Hydrocarbons—Introduction to Formation and Sustainable Exploitation of Mineral Deposits. Walter l. Pohl. 2011. Wiley-Blackwell. Pp. 663. ISBN 978-1-4443-3663-4 (paperback).

Professional illnesses in miners caused by heavy metals and toxic substances

Directory of Open Access Journals (Sweden)

Veličkova N.

2013-01-01

Full Text Available The exposure of humans in an environment contaminated with heavy metals is associated with many diseases, characterized by pathological changes in the respiratory tract, lung function deterioration. The results of the research, conducted with miners working in the “Sasa” lead and zinc mine, were focused on validating the existing professional risk. Most affected are the miners engaged in drilling head and ore. Disease was verified by analysis of acute symptoms. According to the time of exposure, disease symptoms were most frequent after exposure from 1 to 3 years. This indicates that a short span of exposure can be dangerous for some organs, depending on individual hypersensitivity. The most common lung diseases in exposed workers are, chronic bronchitis and tracheitis, chronic obstructive lung disease, pneumoconiosis and silicosis. The multidisciplinary elaboration of the topic, suggests the need for a more serious approach to this important phenomenon (ecotoxicological impact of heavy metals in exposed workers, and also is a specific model that is capable of application and in other related research.

From mineral processing to waste treatment: an open-mind process simulator

International Nuclear Information System (INIS)

Guillaneau, J.C.; Brochot, S.; Durance, M.V.; Villeneuve, J.; Fourniguet, G.; Vedrine, H.; Sandvik, K.; Reuter, M.

1999-01-01

More than two hundred companies are using the USIM PAC process simulator within the mineral industry world-wide. Either for design or plant adaptation, simulation is increasingly supporting the process Engineer in his activities. From the mineral field, new domains have been concerned by this model-based approach as new models are developed and new applications involving solid waste appears. Examples are presented in bio-processing, steel-making flue dust treatment for zinc valorisation, soil decontamination or urban waste valorisation (sorting, composting and incineration). (author)

Minerals Yearbook, volume II, Area Reports—Domestic

Science.gov (United States)

,

2018-01-01

The U.S. Geological Survey (USGS) Minerals Yearbook discusses the performance of the worldwide minerals and materials industries and provides background information to assist in interpreting that performance. Content of the individual Minerals Yearbook volumes follows:Volume I, Metals and Minerals, contains chapters about virtually all metallic and industrial mineral commodities important to the U.S. economy. Chapters on survey methods, summary statistics for domestic nonfuel minerals, and trends in mining and quarrying in the metals and industrial mineral industries in the United States are also included.Volume II, Area Reports: Domestic, contains a chapter on the mineral industry of each of the 50 States and Puerto Rico and the Administered Islands. This volume also has chapters on survey methods and summary statistics of domestic nonfuel minerals.Volume III, Area Reports: International, is published as four separate reports. These regional reports contain the latest available minerals data on more than 180 foreign countries and discuss the importance of minerals to the economies of these nations and the United States. Each report begins with an overview of the region’s mineral industries during the year. It continues with individual country chapters that examine the mining, refining, processing, and use of minerals in each country of the region and how each country’s mineral industry relates to U.S. industry. Most chapters include production tables and industry structure tables, information about Government policies and programs that affect the country’s mineral industry, and an outlook section.The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the Minerals Yearbook are welcomed.

Minerals Yearbook, volume III, Area Reports—International

Science.gov (United States)

,

2018-01-01

The U.S. Geological Survey (USGS) Minerals Yearbook discusses the performance of the worldwide minerals and materials industries and provides background information to assist in interpreting that performance. Content of the individual Minerals Yearbook volumes follows:Volume I, Metals and Minerals, contains chapters about virtually all metallic and industrial mineral commodities important to the U.S. economy. Chapters on survey methods, summary statistics for domestic nonfuel minerals, and trends in mining and quarrying in the metals and industrial mineral industries in the United States are also included.Volume II, Area Reports: Domestic, contains a chapter on the mineral industry of each of the 50 States and Puerto Rico and the Administered Islands. This volume also has chapters on survey methods and summary statistics of domestic nonfuel minerals.Volume III, Area Reports: International, is published as four separate reports. These regional reports contain the latest available minerals data on more than 180 foreign countries and discuss the importance of minerals to the economies of these nations and the United States. Each report begins with an overview of the region’s mineral industries during the year. It continues with individual country chapters that examine the mining, refining, processing, and use of minerals in each country of the region and how each country’s mineral industry relates to U.S. industry. Most chapters include production tables and industry structure tables, information about Government policies and programs that affect the country’s mineral industry, and an outlook section.The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the Minerals Yearbook are welcomed.

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

International Nuclear Information System (INIS)

Liapis, Ioannis; Papayianni, Ioanna

2015-01-01

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 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

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.

Microbe and Mineral Mediated Transformation of Heavy Metals, Radionuclides, and Organic Contaminants

Science.gov (United States)

Gerlach, R.

2011-12-01

Microorganisms influence their surroundings in many ways and humans have utilized microbially catalyzed reactions for benefit for centuries. Over the past few decades, microorganisms have been used for the control of contaminant transport in subsurface environments where many microbe mineral interactions occur. This presentation will discuss microbially influenced mineral formation and transformation as well as their influence on the fate of organic contaminants such as chlorinated aliphatics & 2,4,6-trinitrotoluene (TNT), heavy metals such as chromium, and radionuclides such as uranium & strontium. Both, batch and flow experiments have been performed, which monitor the net effect of microbe mineral interactions on the fate of these contaminants. This invited presentation will place an emphasis on the relative importance of direct microbial (i.e. biotic) transformations, mineral-mediated transformations as well as other abiotic reactions influencing the fate of environmental contaminants. Experiments will be summarized and placed in context of past and future engineered applications for the control of subsurface contaminants.

Electrochemical Applications in Metal Bioleaching.

Science.gov (United States)

Tanne, Christoph Kurt; Schippers, Axel

2017-12-10

Biohydrometallurgy comprises the recovery of metals by biologically catalyzed metal dissolution from solids in an aqueous solution. The application of this kind of bioprocessing is described as "biomining," referring to either bioleaching or biooxidation of sulfide metal ores. Acidophilic iron- and sulfur-oxidizing microorganisms are the key to successful biomining. However, minerals such as primary copper sulfides are recalcitrant to dissolution, which is probably due to their semiconductivity or passivation effects, resulting in low reaction rates. Thus, further improvements of the bioleaching process are recommendable. Mineral sulfide dissolution is based on redox reactions and can be accomplished by electrochemical technologies. The impact of electrochemistry on biohydrometallurgy affects processing as well as analytics. Electroanalysis is still the most widely used electrochemical application in mineralogical research. Electrochemical processing can contribute to bioleaching in two ways. The first approach is the coupling of a mineral sulfide to a galvanic partner or electrocatalyst (spontaneous electron transfer). This approach requires only low energy consumption and takes place without technical installations by the addition of higher redox potential minerals (mostly pyrite), carbonic material, or electrocatalytic ions (mostly silver ions). Consequently, the processed mineral (often chalcopyrite) is preferentially dissolved. The second approach is the application of electrolytic bioreactors (controlled electron transfer). The electrochemical regulation of electrolyte properties by such reactors has found most consideration. It implies the regulation of ferrous and ferric ion ratios, which further results in optimized solution redox potential, less passivation effects, and promotion of microbial activity. However, many questions remain open and it is recommended that reactor and electrode designs are improved, with the aim of finding options for simplified

Oxygen Extraction from Minerals

Science.gov (United States)

Muscatello, Tony

2017-01-01

Oxygen, whether used as part of rocket bipropellant or for astronaut life support, is a key consumable for space exploration and commercialization. In Situ Resource Utilization (ISRU) has been proposed many times as a method for making space exploration more cost effective and sustainable. On planetary and asteroid surfaces the presence of minerals in the regolith that contain oxygen is very common, making them a potential oxygen resource. The majority of research and development for oxygen extraction from minerals has been for lunar regolith although this work would generally be applicable to regolith at other locations in space. This presentation will briefly survey the major methods investigated for oxygen extraction from regolith with a focus on the current status of those methods and possible future development pathways. The major oxygen production methods are (1) extraction from lunar ilmenite (FeTiO3) with either hydrogen or carbon monoxide, (2) carbothermal reduction of iron oxides and silicates with methane, and (3) molten regolith electrolysis (MRE) of silicates. Methods (1) and (2) have also been investigated in a two-step process using CO reduction and carbon deposition followed by carbothermal reduction. All three processes have byproducts that could also be used as resources. Hydrogen or carbon monoxide reduction produce iron metal in small amounts that could potentially be used as construction material. Carbothermal reduction also makes iron metal along with silicon metal and a glass with possible applications. MRE produces iron, silicon, aluminum, titanium, and glass, with higher silicon yields than carbothermal reduction. On Mars and possibly on some moons and asteroids, water is present in the form of mineral hydrates, hydroxyl (-OH) groups on minerals, andor water adsorbed on mineral surfaces. Heating of the minerals can liberate the water which can be electrolyzed to provide a source of oxygen as well. The chemistry of these processes, some key

Proceedings of the international symposium on control and optimization in minerals, metals and materials processing

International Nuclear Information System (INIS)

Hodouin, D.; Bazin, C.; Desbiens, A.

1999-01-01

This is the first symposium on Process optimization and Control in Ore Processing, Extractive Metallurgy and Material Science ever sponsored by Metsoc. Sure enough, papers dealing with these topics are regularly presented at the Annual Conference of Metallurgists, but they have always been, so far, scattered through different symposia dealing with specific mineral or metallurgical processes. The novelty, at this symposium, is that our central theme reflects the methods rather than the processes, a change of focus that should foster interdisciplinary exchanges in Metallurgical Engineering. The various methods reviewed in the symposium proceedings are presented in four chapters covering the following topics: data acquisition and filtering, process monitoring; process modelling; process control; and process optimization. We hope that the 41 papers collected in this volume can sensitize the reader to the importance of modern data processing techniques for the valorization of available process data to improve the metallurgical and economic efficiency of industrial processes. They should also incite production managers, research directors and educational leaders to expand their efforts in the field

Separation of the metallic and non-metallic fraction from printed circuit boards employing green technology

Energy Technology Data Exchange (ETDEWEB)

Estrada-Ruiz, R.H., E-mail: rhestrada@itsaltillo.edu.mx; Flores-Campos, R., E-mail: rcampos@itsaltillo.edu.mx; Gámez-Altamirano, H.A., E-mail: hgamez@itsaltillo.edu.mx; Velarde-Sánchez, E.J., E-mail: ejvelarde@itsaltillo.edu.mx

2016-07-05

Highlights: • Small sizes of particles are required in order to separate the different fractions. • Inverse flotation process is an efficient green technology to separate fractions. • Superficial air velocity is the main variable in the inverse flotation process. • Inverse flotation is a green process because the pulṕs pH is 7.0 during the test. - Abstract: The generation of electrical and electronic waste is increasing day by day; recycling is attractive because of the metallic fraction containing these. Nevertheless, conventional techniques are highly polluting. The comminution of the printed circuit boards followed by an inverse flotation process is a clean technique that allows one to separate the metallic fraction from the non-metallic fraction. It was found that particle size and superficial air velocity are the main variables in the separation of the different fractions. In this way an efficient separation is achieved by avoiding the environmental contamination coupled with the possible utilization of the different fractions obtained.

Biorefine: Recovery of nutrients and metallic trace elements from different wastes by chemical and biochemical processes

OpenAIRE

Tarayre, Cédric; Fischer, Christophe; De Clercq, Lies; Michels, Evi; Meers, Erik; Buysse, Jeroen; Delvigne, Frank; Thonart, Philippe

2014-01-01

At present, most waste processing operations are not oriented towards the valorization of valuable reusable components such as nitrogen, phosphorus, potassium and even Metallic Trace Elements (MTEs). Currently, sewage sludge, for example is usually used as a fertilizer in agriculture, in energy production or in the field of construction. Ashes originating from sludge incineration contain heavy metals and minerals in large quantities. Manure is mainly used in agriculture, although considerable...

Performance evaluation of a biodiesel fuelled transportation engine retrofitted with a non-noble metal catalysed diesel oxidation catalyst for controlling unregulated emissions.

Science.gov (United States)

Shukla, Pravesh Chandra; Gupta, Tarun; Agarwal, Avinash Kumar

2018-02-15

In present study, engine exhaust was sampled for measurement and analysis of unregulated emissions from a four cylinder transportation diesel engine using a state-of-the-art FTIR (Fourier transform infrared spectroscopy) emission analyzer. Test fuels used were Karanja biodiesel blend (B20) and baseline mineral diesel. Real-time emission measurements were performed for raw exhaust as well as exhaust sampled downstream of the two in-house prepared non-noble metal based diesel oxidation catalysts (DOCs) and a baseline commercial DOC based on noble metals. Two prepared non-noble metal based DOCs were based on Co-Ce mixed oxide and Lanthanum based perovskite catalysts. Perovskite based DOC performed superior compared to Co-Ce mixed oxide catalyst based DOC. Commercial noble metal based DOC was found to be the most effective in reducing unregulated hydrocarbon emissions in the engine exhaust, followed by the two in-house prepared non-noble metal based DOCs. Copyright © 2017 Elsevier B.V. All rights reserved.

A double metal process

International Nuclear Information System (INIS)

Hawley, F.; Vasche, G.; Caywood, J.M.; Houck, B.; Boyce, J.; Tso, L.

1988-01-01

A dual layer metallization process is studied using a Tungsten 10% Titanium/Molybdenum sandwich (TiW/Mo) first metal with an Al/.5% Cu for the second metal. This metallization process has: 1) very reliable shallow junction contacts without junction spiking, 2) very high electromigration resistance and (3) A very smooth defect free surface throughout the process. Contact resistance of 50 and 30 ohm-um2 for P and N type silicon respectively is achieved. The TiW/Mo film stress is studied and an optimum condition for low compressive stress is defined. The TiW/Mo is etched using a corrosion free etch process. Electromigration data is presented showing TiW/Mo to be at least an order of magnitude better than Al/Si. The intermetal oxide layer is a planarized sandwich of LTO/SOG/LTO providing a smooth positive slope surface for the Metal 2. Metal l/Metal 2 via resistances are studied with 1.25 ohm-um2 values obtained

Microbial weathering processes after release of heavy metals and arsenic from fluvial tailing deposits; Mikrobielle Verwitterungsprozesse bei der Freisetzung von Schwermetallen und Arsen aus fluvialen Tailingablagerungen

Energy Technology Data Exchange (ETDEWEB)

Willscher, S. [Technische Univ. Dresden (Germany). Fak. fuer Forst, Geo und Hydrowissenschaften, Inst. fuer Abfallwirtschaft und Altlasten

2006-07-01

Microbial processes play an important role in global metal cycles. The microbial weathering of mineral surfaces, including deposited anthropogenic mineral remainders, is a natural occurring process, taking place on uncovered dump surfaces as well as in deeper zones of dumps. Such weathering processes also occur in metal contaminated soils and sediments. In this work, a sulfidic fluvial tailing sediment was investigated for its acidity and salinity generating potential and the subsequent mobilisation of heavy metals, generated by biogeochemical processes. The long-term risks of such a deposit were evaluated. Unstabilised deposits of such materials can generate a considerable contamination of the surrounding ground and surface water. It could be shown in the experiments that in acid generating dumps and tailing materials besides the well known acidophilic autotrophs also acidotolerant heterotrophic microorganisms play a role in the mobilisation of metals. (orig.)

An exploration in mineral supply chain mapping using tantalum as an example

Science.gov (United States)

Soto-Viruet, Yadira; Menzie, W. David; Papp, John F.; Yager, Thomas R.

2013-01-01

This report uses the supply chain of tantalum (Ta) to investigate the complexity of mineral and metal supply chains in general and show how they can be mapped. A supply chain is made up of all the manufacturers, suppliers, information networks, and so forth, that provide the materials and parts that go into making up a final product. The mineral portion of the supply chain begins with mineral material in the ground (the ore deposit); extends through a series of processes that include mining, beneficiation, processing (smelting and refining), semimanufacture, and manufacture; and continues through transformation of the mineral ore into concentrates, refined mineral commodities, intermediate forms (such as metals and alloys), component parts, and, finally, complex products. This study analyses the supply chain of tantalum beginning with minerals in the ground to many of the final goods that contain tantalum.

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.

Contribution of nuclear analysis methods to the certification of BCR reference materials for non-metals in non-ferrous metals

International Nuclear Information System (INIS)

Pauwels, J.

1979-01-01

A number of reference materials for oxygen in different non-ferrous metals have been certified by BCR in the frame of a multidisciplinary Community project. The contribution of nuclear analysis methods is illustrated by several examples concerning the optimization of sample preparation techniques, the analysis of low and high oxygen non-ferrous metals and the extension of the program to other non-metals, especially nitrogen and carbon. (author)

Webinar Presentation: Vitamins, Minerals and Metals: Do Healthy Diets Counteract Health Effects of Toxicants?

Science.gov (United States)

This presentation, Vitamins, Minerals and Metals: Do Healthy Diets Counteract Health Effects of Toxicants?, was given at the NIEHS/EPA Children's Centers 2015 Webinar Series: Food and Children's Health held on Dec. 9, 2015.

Minerals, Toxic Heavy Metals, and Antioxidant Properties of Honeys from Bangladesh

Directory of Open Access Journals (Sweden)

Sudip Paul

2017-01-01

Full Text Available The study reports on major and trace elements as well as antioxidant properties of honey samples from Bangladesh. Four major cationic elements, seven trace elements, and three heavy metals were determined in the 12 honey samples using atomic absorption spectrophotometer. Nutritional values in these honey samples were further investigated according to their antioxidant properties. The content of major elements was in the range of 62.75–616.58, 579.48–2219.43, 69.42–632.25, and 0.13–1.20 mg/kg for sodium, potassium, magnesium, and calcium, respectively. The trace elements varied in the range of 0.41–28, 0.12–3.54, 1.54–2.85, 0.29–0.59, 0.02–0.35, and 0.01–0.06 mg/kg for iron, zinc, copper, nickel, cobalt, and cadmium, respectively. Among the heavy metals, only lead (0.17–2.19 mg/kg was detected. The results of antioxidant analysis based on phenolics, flavonoids, ascorbic acid, reducing sugar, and proteins (as nonphenolic antioxidants revealed that multifloral raw honey samples contain significantly higher levels of reducing agents than monofloral and commercial brand honeys. The study provides a useful insight on the minerals, heavy metals, and antioxidant properties of honey samples commonly consumed in Bangladesh and found to be rich source of antioxidants and minerals. Some samples might pose some risk to the health due to lead contamination.

Comprehensive recovery of gold and base-metal sulfide minerals from a low-grade refractory ore

Science.gov (United States)

Li, Wen-juan; Liu, Shuang; Song, Yong-sheng; Wen, Jian-kang; Zhou, Gui-ying; Chen, Yong

2016-12-01

The comprehensive recovery of small amounts of valuable minerals such as gold and base-metal sulfide minerals from a low-grade refractory ore was investigated. The following treatment strategy was applied to a sample of this ore: gold flotation-gold concentrate leaching-lead and zinc flotation from the gold concentrate leaching residue. Closed-circuit trials of gold flotation yielded a gold concentrate that assayed at 40.23 g·t-1 Au with a recovery of 86.25%. The gold concentrate leaching rate was 98.76%. Two variants of lead-zinc flotation from the residue—preferential flotation of lead and zinc and bulk flotation of lead and zinc—were tested using the middling processing method. Foam from the reflotation was returned to the lead rougher flotation or lead-zinc bulk flotation, whereas middlings from reflotation were discarded. Sulfur concentrate was a byproduct. The combined strategy of flotation, leaching, and flotation is recommended for the treatment of this kind of ore.

Mineralization of Carbon Dioxide: Literature Review

Energy Technology Data Exchange (ETDEWEB)

Romanov, V; Soong, Y; Carney, C; Rush, G; Nielsen, B; O' Connor, W

2015-01-01

CCS research has been focused on CO2 storage in geologic formations, with many potential risks. An alternative to conventional geologic storage is carbon mineralization, where CO2 is reacted with metal cations to form carbonate minerals. Mineralization methods can be broadly divided into two categories: in situ and ex situ. In situ mineralization, or mineral trapping, is a component of underground geologic sequestration, in which a portion of the injected CO2 reacts with alkaline rock present in the target formation to form solid carbonate species. In ex situ mineralization, the carbonation reaction occurs above ground, within a separate reactor or industrial process. This literature review is meant to provide an update on the current status of research on CO2 mineralization. 2

New Approach for Fractioning Metal Compounds Studies in Soils

Science.gov (United States)

Minkina, Tatiana; Motuzova, Galina; Mandzhieva, Saglara; Bauer, Tatiana; Burachevskaya, Marina; Sushkova, Svetlana; Nevidomskaya, Dina; Kalinitchenko, Valeriy

2016-04-01

A combined approach for fractioning metal compounds in soils on the basis of sequential (Tessier, 1979) and parallel extractions (1 N NH4Ac, pH 8; 1% EDTA in NH4Ac; and 1N HCl) is proposed. Metal compounds in sequential and parallel extracts are grouped according to the strength of their bonds with soil components. A given group includes metal compounds with similar strengths of bonds and, hence, with similar migration capacities. The groups of firmly and loosely bound metal compounds can be distinguished. This approach has been used to assess the group composition of Zn, Cu, and Pb compounds in an ordinary chernozem and its changes upon the soil contamination with metals. Contamination of an ordinary chernozem from Rostov oblast with heavy metals caused a disturbance of the natural ratios between the metal compounds. In the natural soil, firmly bound metals predominate (88-95%of the total content), which is mainly caused by the fixation of metals in lattices of silicate minerals (56-83%of the total content). The mobility of the metals in the natural soil is low (5-12%) and is mainly related to metal compounds loosely bound with the soil carbonates. Upon the soil contamination with metals (application rates of 100-300 mg/kg), the content of all the metal compounds increases, but the ratio between them shifts towards a higher portion of the potentially mobile metal compounds (up to 30-40% of the bulk contents of the metals). Organic substances and non-silicate Fe, Al, and Mn minerals become the main carriers of the firmly and loosely bound metals. The strengths of their bonds with Cu, Pb, and Zn differ. Lead in the studied chernozems is mainly fixed in a loosely bound form with organic matter, whereas copper and zinc are fixed both by the organic matter and by the non-silicate Fe, Al, and Mn compounds. Firm fixation of the applied Cu and Pb is mainly ensured by the soil organic matter and non-silicate minerals, whereas firm fixation of Zn is mainly due to non

Silicosis and lung cancer in U.S. metal miners

International Nuclear Information System (INIS)

Amandus, H.; Costello, J.

1991-01-01

The association between silicosis and lung cancer mortality was estimated in 9,912 (369 silicotics and 9,543 nonsilicotics) white male metal miners. These miners were examined by the U.S. Public Health Service during 1959-1961 and were followed through 1975. Miners were excluded from this study if they were employed in a mine during 1959-1961 that used diesel equipment underground. The ores that were mined consisted of copper, lead-zinc, iron, mercury, lead silver, gold and gold-silver, tungsten, and molybdenum. The standardized mortality ratio (SMR, U.S. white male rates) for lung cancer was 1.73 (95% CI: .94-2.90) in silicotics and 1.18 (95% CI: .98-1.42) in nonsilicotics. Additionally, SMRs were higher in silicotics than in nonsilicotics, even in most subgroups stratified by cigarette smoking habit, type of ore mined, years of service in an underground job, radon exposure group, or year of hire. When lung cancer mortality between silicotics and nonsilicotics was compared, the age-adjusted rate ratio (95% CI) was 1.56 (.91-2.68), and the age- and smoking-adjusted rate ratio was 1.96 (.98-3.67). Corresponding figures for miners who were employed in mines with low levels of radon exposure were 1.90 (.98-3.67) and 2.59 (1.44-4.68), respectively. These findings indicate that lung cancer mortality risk was increased in silicotics, and this probably did not result from chance or bias. However, confounding from radon exposure could not be ruled out. The findings indicate that further follow-up of this cohort is needed

Comparative study of metal and non-metal ion implantation in polymers: Optical and electrical properties

International Nuclear Information System (INIS)

Resta, V.; Quarta, G.; Farella, I.; Maruccio, L.; Cola, A.; Calcagnile, L.

2014-01-01

The implantation of 1 MeV metal ( 63 Cu + , 107 Ag + , 197 Au + ) and non-metal ( 4 He + , 12 C + ) ions in a polycarbonate (PC) matrix has been studied in order to evaluate the role of ion species in the modification of optical and electrical properties of the polymer. When the ion fluence is above ∼1 × 10 13 ions cm −2 , the threshold for latent tracks overlapping is overcome and π-bonded carbon clusters grow and aggregate forming a network of conjugated C=C bonds. For fluences around 1 × 10 17 ions cm −2 , the aggregation phenomena induce the formation of amorphous carbon and/or graphite like structures. At the same time, nucleation of metal nanoparticles (NPs) from implanted species can take place when the supersaturation threshold is overcome. The optical absorption of the samples increases in the visible range and the optical band gap redshifts from 3.40 eV up to 0.70 eV mostly due to the carbonization process and the formation of C 0x clusters and cluster aggregates. Specific structures in the extinction spectra are observed when metal ions are selected in contrast to the non-metal ion implanted PC, thus revealing the possible presence of noble metal based NPs interstitial to the C 0x cluster network. The corresponding electrical resistance decreases much more when metal ions are implanted with at least a factor of 2 orders of magnitude difference than the non-metal ions based samples. An absolute value of ∼10 7 Ω/sq has been measured for implantation with metals at doses higher than 5 × 10 16 ions cm −2 , being 10 17 Ω/sq the corresponding sheet resistance for pristine PC

Comparative study of metal and non-metal ion implantation in polymers: Optical and electrical properties

Energy Technology Data Exchange (ETDEWEB)

Resta, V., E-mail: vincenzo.resta@le.infn.it [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy); Quarta, G. [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy); Farella, I. [Institute for Microelectronics and Microsystems – Unit of Lecce, National Council of Research (IMM/CNR), Lecce I-73100 (Italy); Maruccio, L. [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy); Cola, A. [Institute for Microelectronics and Microsystems – Unit of Lecce, National Council of Research (IMM/CNR), Lecce I-73100 (Italy); Calcagnile, L. [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy)

2014-07-15

The implantation of 1 MeV metal ({sup 63}Cu{sup +}, {sup 107}Ag{sup +}, {sup 197}Au{sup +}) and non-metal ({sup 4}He{sup +}, {sup 12}C{sup +}) ions in a polycarbonate (PC) matrix has been studied in order to evaluate the role of ion species in the modification of optical and electrical properties of the polymer. When the ion fluence is above ∼1 × 10{sup 13} ions cm{sup −2}, the threshold for latent tracks overlapping is overcome and π-bonded carbon clusters grow and aggregate forming a network of conjugated C=C bonds. For fluences around 1 × 10{sup 17} ions cm{sup −2}, the aggregation phenomena induce the formation of amorphous carbon and/or graphite like structures. At the same time, nucleation of metal nanoparticles (NPs) from implanted species can take place when the supersaturation threshold is overcome. The optical absorption of the samples increases in the visible range and the optical band gap redshifts from 3.40 eV up to 0.70 eV mostly due to the carbonization process and the formation of C{sub 0x} clusters and cluster aggregates. Specific structures in the extinction spectra are observed when metal ions are selected in contrast to the non-metal ion implanted PC, thus revealing the possible presence of noble metal based NPs interstitial to the C{sub 0x} cluster network. The corresponding electrical resistance decreases much more when metal ions are implanted with at least a factor of 2 orders of magnitude difference than the non-metal ions based samples. An absolute value of ∼10{sup 7} Ω/sq has been measured for implantation with metals at doses higher than 5 × 10{sup 16} ions cm{sup −2}, being 10{sup 17} Ω/sq the corresponding sheet resistance for pristine PC.

Validation of the Ventgraph program for use in metal/non-metal mines

Energy Technology Data Exchange (ETDEWEB)

Pritchard, C.J. [National Inst. for Occupational Safety and Health, Spokane, WA (United States)

2010-07-01

Ventgraph is a ventilation software developed by the Polish Academy of Sciences. It has features similar to other ventilation programs, such as network simulation and contaminant dispersal. Its additional capabilities include mine fire simulation, compressible flow modelling, and real-time on-screen visualization of mine ventilation and fire effects. For that reason, it has been widely used around the world for studying coal mine fires, fighting fires with inert gases, spontaneous combustion, and mine emergency exercises. Ventgraph has been used to a much lesser extent in metal/non-metal (M/NM) mines. The National Institute for Occupational Safety and Health has determined that the use of Ventgraph to hardrock mining methods would be beneficial for studying M/NM ventilation effects, mine evacuation training, risk analysis of potential mine ventilation changes, airborne contaminants, recirculation, and mine fires. Ventgraph was used to simulate the 1972 Sunshine Mine fire where 91 miners perished. The Sunshine Mine was chosen because of its deep, complex ventilation system. Calibration of Ventgraph's fire simulation module to known events of the fire showed close correlation to contaminant levels observed and real-time movement of fire combustion products through the mine. It was concluded that Ventgraph is a valuable tool for M/NM mine ventilation, fire, and evacuation planning. 13 refs., 3 figs.

Damage parameters for non-metals in a high energy neutron environment

International Nuclear Information System (INIS)

Dell, G.F.; Berry, H.C.; Lazareth, O.W.; Goland, A.N.

1980-01-01

Simulation of radiation damage induced in monatomic and binary non-metals by FMIT and fusion neutrons is described. Damage produced by elastic scattering of recoil atoms and by ionization-assisted processes has been evaluated using the damage program DON. Displacement damage from gamma rays has been evaluated by using the technique of Oen and Holmes. A comparison of damage for an anticipated FMIT radiation environment generated by a coupled n-γ transport calculations and a fusion spectrum is made. Gamma-induced displacement damage is sufficiently small that it is dominated by neutron-induced recoil processes. Ionization-assisted displacements may be important depending upon the ionization cross section of the particular non-metal under consideration

Chemical changes of minerals trapped in the lichen Trapelia involuta. Implication for lichen effect on mobility of uranium and toxic metals

International Nuclear Information System (INIS)

Kasama, Takeshi; Murakami, Takashi; Ohnuki, Toshihiko

2002-01-01

To elucidate development of minerals trapped in a lichen, we examined the lichen Trapelia involuta growing directly on secondary uranyl minerals and U-enriched Fe oxide and hydroxide minerals. Sericite and other minerals in the underlying rock are trapped in the lichen T. involuta during its biological growth and chemically changed by lichen activities. The presence of chemically changed sericite accompanied by an Fe-bearing mineral in the lichen suggests that dissolution of sericite is promoted mainly by polysaccharides excreted by the lichen. Oxalic acid or lichen acids absent in the medulla may not play an important role in the dissolution. Our results suggest that lichens on metal-rich surface affect the mobility of uranium and other toxic metals through dissolution followed by trap of minerals from the underlying rock. (author)

Molten salt extraction process for the recovery of valued transition metals from land-based and deep-sea minerals

Science.gov (United States)

Maroni, V.A.; von Winbush, S.

1987-05-01

A process for extracting transition metals and particularly cobalt and manganese together with iron, copper and nickel from low grade ores (including ocean-floor nodules) by converting the metal oxides or other compositions to chlorides in a molten salt, and subsequently using a combination of selective distillation at temperatures below about 500/degree/C, electrolysis at a voltage not more negative that about /minus/1.5 volt versus Ag/AgCl, and precipitation to separate the desired manganese and cobalt salts from other metals and provide cobalt and manganese in metallic forms or compositions from which these metals may be more easily recovered.

Characterization and mechanical separation of metals from computer Printed Circuit Boards (PCBs) based on mineral processing methods.

Science.gov (United States)

Sarvar, Mojtaba; Salarirad, Mohammad Mehdi; Shabani, Mohammad Amin

2015-11-01

In this paper, a novel mechanical process is proposed for enriching metal content of computer Printed Circuit Boards (PCBs). The PCBs are crushed and divided into three different size fractions namely: -0.59, +0.59 to 1.68 and +1.68 mm. Wet jigging and froth flotation methods are selected for metal enrichment. The coarse size fraction (+1.68 mm) is processed by jigging. The plastic free product is grinded and screened. The oversized product is separated as the first concentrate. It was rich of metal because the grinding process was selective. The undersized product is processed by froth flotation. Based on the obtained results, the middle size fraction (+0.59 to 1.68 mm) and the small size fraction (-0.59 mm) are processed by wet jigging and froth flotation respectively. The wet jigging process is optimized by investigating the effect of pulsation frequency and water flow rate. The results of examining the effect of particle size, solid to liquid ratio, conditioning time and using apolar collector showed that collectorless flotation is a promising method for separating nonmetals of PCBs. 95.6%, 97.5% and 85% of metal content of coarse size, middle size and small size fraction are recovered. The grades of obtained concentrates were 63.3%, 92.5% and 75% respectively. The total recovery is calculated as 95.64% and the grade of the final concentrate was 71.26%. Determining the grade of copper and gold in the final product reveals that 4.95% of copper and 24.46% of gold are lost during the concentration. The major part of the lost gold is accumulated in froth flotation tail. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of mineral resource potential of the Finnish precambrian

International Nuclear Information System (INIS)

Peltonen, K.

1993-05-01

In the report the undiscovered mineral resource potential of metallogenic regions in Finland is evaluated. The evaluation is based on known deposits. The criteria of the evaluation were: ore and mineral deposit density, regional distribution of valuable metals, and the amount and the nature of prospecting methods used. The information for the study has been collected from the data base for ore minerals maintained by the Geological Survey of Finland. Regions with mineral resource potential conclusively under national average are Presvecokarelidic and Svecokarelidic granitoids and rapakivi Massif. The mineral resource potential of basic rocks in relation to their surface area is multiple compared to non-basic rocks

Metal nanostructures for non-enzymatic glucose sensing

International Nuclear Information System (INIS)

Tee, Si Yin; Teng, Choon Peng; Ye, Enyi

2017-01-01

This review covers the recent development of metal nanostructures in electrochemical non-enzymatic glucose sensing. It highlights a variety of nanostructured materials including noble metals, other transition metals, bimetallic systems, and their hybrid with carbon-based nanomaterials. Particularly, attention is devoted to numerous approaches that have been implemented for improving the sensors performance by tailoring size, shape, composition, effective surface area, adsorption capability and electron-transfer properties. The correlation of the metal nanostructures to the glucose sensing performance is addressed with respect to the linear concentration range, sensitivity and detection limit. In overall, this review provides important clues from the recent scientific achievements of glucose sensor nanomaterials which will be essentially useful in designing better and more effective electrocatalysts for future electrochemical sensing industry. - Highlights: • Overview of recent development of metal nanostructures in electrochemical non-enzymatic glucose sensing. • Special attention is focussed on noble metals, other transition metals, bimetallic systems, and their hybrid with carbon-based nanomaterials. • Merits and limitations of various metal nanostructures in electrochemical non-enzymatic glucose sensing. • Strategies to improve the glucose sensing performance of metal nanostructures as electrocatalysts.

Process for improving metal production in steelmaking processes

Science.gov (United States)

Pal, Uday B.; Gazula, Gopala K. M.; Hasham, Ali

1996-01-01

A process and apparatus for improving metal production in ironmaking and steelmaking processes is disclosed. The use of an inert metallic conductor in the slag containing crucible and the addition of a transition metal oxide to the slag are the disclosed process improvements.

Mineral composition of non-conventional leafy vegetables.

Science.gov (United States)

Barminas, J T; Charles, M; Emmanuel, D

1998-01-01

Six non-conventional leafy vegetables consumed largely by the rural populace of Nigeria were analyzed for mineral composition. Mineral contents appeared to be dependent on the type of vegetables. Amaranthus spinosus and Adansonia digitata leaves contained the highest level of iron (38.4 mg/100 g and 30.6 mg/100 g dw, respectively). These values are low compared to those for common Nigerian vegetables but higher than those for other food sources. All the vegetables contained high levels of calcium compared to common vegetables, thus they could be a rich source of this mineral. Microelement content of the leaves varied appreciably. Zinc content was highest in Moringa oleifera, Adansonia digitata and Cassia tora leaves (25.5 mg/100 g, 22.4 mg/100 g and 20.9 mg/100 g dw, respectively) while the manganese content was comparatively higher in Colocasia esculenta. The concentrations of the mineral elements in the vegetables per serving portion are presented and these values indicate that the local vegetables could be valuable and important contributors in the diets of the rural and urban people of Nigeria. The mean daily intake of P, Mg, Ca, Fe, Cu and Zn were lower than their recommended dietary allowances (RDAs). However, the manganese daily intake was found not to differ significantly (p = 0.05) from the RDA value.

Review of Biohydrometallurgical Metals Extraction from Polymetallic Mineral Resources

Directory of Open Access Journals (Sweden)

Helen R. Watling

2014-12-01

Full Text Available This review has as its underlying premise the need to become proficient in delivering a suite of element or metal products from polymetallic ores to avoid the predicted exhaustion of key metals in demand in technological societies. Many technologies, proven or still to be developed, will assist in meeting the demands of the next generation for trace and rare metals, potentially including the broader application of biohydrometallurgy for the extraction of multiple metals from low-grade and complex ores. Developed biotechnologies that could be applied are briefly reviewed and some of the difficulties to be overcome highlighted. Examples of the bioleaching of polymetallic mineral resources using different combinations of those technologies are described for polymetallic sulfide concentrates, low-grade sulfide and oxidised ores. Three areas for further research are: (i the development of sophisticated continuous vat bioreactors with additional controls; (ii in situ and in stope bioleaching and the need to solve problems associated with microbial activity in that scenario; and (iii the exploitation of sulfur-oxidising microorganisms that, under specific anaerobic leaching conditions, reduce and solubilise refractory iron(III or manganese(IV compounds containing multiple elements. Finally, with the successful applications of stirred tank bioleaching to a polymetallic tailings dump and heap bioleaching to a polymetallic black schist ore, there is no reason why those proven technologies should not be more widely applied.

Emerging industrial processes for low grade rare earth mineral concentrates

International Nuclear Information System (INIS)

Soldenhoff, Karin; Ho, Elizabeth

2015-01-01

Historically rare earth recovery has mainly been derived from the processing of monazite, bastnasite and xenotime containing ores amenable to beneficiation, yielding high grade mineral concentrates. A notable exception is the recovery of heavy rare earths from ionic clays in Southern China. Recently, projects are being proposed to treat a range of mineral concentrates which tend to be lower grade with wide ranging modal mineralogy for rare earths and associated gangue minerals. This has a significant impact on processing routes. This paper discusses processes proposed for emerging rare earth producers and how different projects have responded to particular challenges including: Control of phosphorous due to the presence of xenotime or monazite type minerals; Control of phosphorous due to the presence of rare earth containing apatite; Rare earth recovery from polymetallic ores; Control of radionuclides in rare earth processing, etc.

Solar Convective Furnace for Metals Processing

Science.gov (United States)

Patidar, Deepesh; Tiwari, Sheetanshu; Sharma, Piyush; Pardeshi, Ravindra; Chandra, Laltu; Shekhar, Rajiv

2015-11-01

Metals processing operations, primarily soaking, heat treatment, and melting of metals are energy-intensive processes using fossil fuels, either directly or indirectly as electricity, to operate furnaces at high temperatures. Use of concentrated solar energy as a source of heat could be a viable "green" option for industrial heat treatment furnaces. This paper introduces the concept of a solar convective furnace which utilizes hot air generated by an open volumetric air receiver (OVAR)-based solar tower technology. The potential for heating air above 1000°C exists. Air temperatures of 700°C have already been achieved in a 1.5-MWe volumetric air receiver demonstration plant. Efforts to retrofit an industrial aluminium soaking furnace for integration with a solar tower system are briefly described. The design and performance of an OVAR has been discussed. A strategy for designing a 1/15th-scale model of an industrial aluminium soaking furnace has been presented. Preliminary flow and thermal simulation results suggest the presence of recirculating flow in existing furnaces that could possibly result in non-uniform heating of the slabs. The multifarious uses of concentrated solar energy, for example in smelting, metals processing, and even fuel production, should enable it to overcome its cost disadvantage with respect to solar photovoltaics.

Particle morphology and mineral structure of heavy metal-contaminated kaolin soil before and after electrokinetic remediation.

Science.gov (United States)

Roach, Nicole; Reddy, Krishna R; Al-Hamdan, Ashraf Z

2009-06-15

This study aims to characterize the physical distribution of heavy metals in kaolin soil and the chemical and structural changes in kaolinite minerals that result from electrokinetic remediation. Three bench-scale electrokinetic experiments were conducted on kaolin that was spiked with Cr(VI) alone, Ni (II) alone, and a combination of Cr(VI), Ni(II) and Cd(II) under a constant electric potential of 1VDC/cm for a total duration of 4 days. Transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analyses were performed on the soil samples before and after electrokinetic remediation. Results showed that the heavy metal contaminant distribution in the soil samples was not observable using TEM and EDX. EDX detected nickel and chromium on some kaolinite particles and titanium-rich, high-contrast particles, but no separate phases containing the metal contaminants were detected. Small amounts of heavy metal contaminants that were detected by EDX in the absence of a visible phase suggest that ions are adsorbed to kaolinite particle surfaces as a thin coating. There was also no clear correlation between semiquantitative analysis of EDX spectra and measured total metal concentrations, which may be attributed to low heavy metal concentrations and small size of samples used. X-ray diffraction analyses were aimed to detect any structural changes in kaolinite minerals resulting from EK. The diffraction patterns showed a decrease in peak height with decreasing soil pH value, which indicates possible dissolution of kaolinite minerals during electrokinetic remediation. Overall this study showed that the changes in particle morphology were found to be insignificant, but a relationship was found between the crystallinity of kaolin and the pH changes induced by the applied electric potential.

Particle morphology and mineral structure of heavy metal-contaminated kaolin soil before and after electrokinetic remediation

International Nuclear Information System (INIS)

Roach, Nicole; Reddy, Krishna R.; Al-Hamdan, Ashraf Z.

2009-01-01

This study aims to characterize the physical distribution of heavy metals in kaolin soil and the chemical and structural changes in kaolinite minerals that result from electrokinetic remediation. Three bench-scale electrokinetic experiments were conducted on kaolin that was spiked with Cr(VI) alone, Ni (II) alone, and a combination of Cr(VI), Ni(II) and Cd(II) under a constant electric potential of 1 VDC/cm for a total duration of 4 days. Transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analyses were performed on the soil samples before and after electrokinetic remediation. Results showed that the heavy metal contaminant distribution in the soil samples was not observable using TEM and EDX. EDX detected nickel and chromium on some kaolinite particles and titanium-rich, high-contrast particles, but no separate phases containing the metal contaminants were detected. Small amounts of heavy metal contaminants that were detected by EDX in the absence of a visible phase suggest that ions are adsorbed to kaolinite particle surfaces as a thin coating. There was also no clear correlation between semiquantitative analysis of EDX spectra and measured total metal concentrations, which may be attributed to low heavy metal concentrations and small size of samples used. X-ray diffraction analyses were aimed to detect any structural changes in kaolinite minerals resulting from EK. The diffraction patterns showed a decrease in peak height with decreasing soil pH value, which indicates possible dissolution of kaolinite minerals during electrokinetic remediation. Overall this study showed that the changes in particle morphology were found to be insignificant, but a relationship was found between the crystallinity of kaolin and the pH changes induced by the applied electric potential.

Molecular orbital (SCF-Xα-SW) theory of metal-metal charge transfer processes in minerals - II. Application to Fe2+ --> Ti4+ charge transfer transitions in oxides and silicates

Science.gov (United States)

Sherman, David M.

1987-01-01

A molecular orbital description, based on Xα-Scattered wave calculations on a (FeTiO10)14− cluster, is given for Fe2+ → Ti4+ charge transfer transitions in minerals. The calculated energy for the lowest Fe2+ → Ti4+ metal-metal charge transfer transition is 18040 cm−1 in reasonable agreement with energies observed in the optical spectra of Fe-Ti oxides and silicates. As in the case of Fe2+ → Fe3+ charge transfer in mixed-valence iron oxides and silicates, Fe2+ → Ti4+ charge transfer is associated with Fe-Ti bonding across shared polyhedral edges. Such bonding results from the overlap of the Fe(t 2g ) and Ti(t 2g ) 3d orbitals.

The Genesis of Precious and Base Metal Mineralization at the Miguel Auza Deposit, Zacatecas, Mexico

Science.gov (United States)

Findley, A. A.; Olivo, G. R.; Godin, L.

2009-05-01

The Miguel Auza mine located in Zacatecas State, Mexico, is a vein-type polymetallic epithermal deposit hosted in deformed argillite, siltstone and, greywacke of the Cretaceous Caracol Formation. Silver-rich base metal veins (0.2 m to >1.5 m wide) are spatially associated with the NE-striking, steeply SE- dipping (70-80°) Miguel Auza fault over a strike length of 1.6 km and a depth of 460 m. A 2 km2 monzonitic stock located in the proximity of the mineralized zones, has previously been interpreted as the source of the mineralizing fluids. Four distinct structural stages are correlated with hydrothermal mineral deposition: (I) The Pre-ore stage is characterized by normal faulting, fracturing of host rock, and rotation of bedding planes. This stage consists of quartz, illite, chlorite, +/- pyrite alteration of sedimentary wall rocks. (II) The Pyrite-vein stage is associated with reverse-sense reactivation of early normal faults, dilation of bedding planes/fractures, and deposition of generally barren calcite + pyrite veinlets. (III) The Main-ore stage is related to the development of reverse-fault- hosted massive sulphide veins. During this stage three phases of mineral deposition are recorded: early pyrite and arsenopyrite, intermediate chalcopyrite, pyrite, arsenopyrite, and base metals, and late base metals and Ag-bearing minerals. Associated gangue minerals during the main ore stage are quartz, muscovite, calcite and chlorite. (IV) The Post-ore stage involves late NW-SE striking block faulting, brecciation and calcite veining. Later supergene oxidation of veins led to deposition of Fe-oxides and hydroxides, commonly filling fractures or replacing early-formed sulphide assemblages. The various vein types display classic epithermal textures including open space filling, banding, comb quartz and brecciation. The Ag-bearing minerals comprise pyrargyrite [Ag3(Sb,As)S3], argentotennantite [(Cu,Ag)10(Zn,Fe)2(Sn,As)4S13], polybasite-pearceite [(Ag,Cu)16(Sb,As)2S11], and

Tannins in Mineral Processing and Extractive Metallurgy

Directory of Open Access Journals (Sweden)

Jordan Rutledge

2015-08-01

Full Text Available This study provides an up to date review of tannins, specifically quebracho, in mineral processing and metallurgical processes. Quebracho is a highly useful reagent in many flotation applications, acting as both a depressant and a dispersant. Three different types of quebracho are mentioned in this study; quebracho “S” or Tupasol ATO, quebracho “O” or Tupafin ATO, and quebracho “A” or Silvafloc. It should be noted that literature often refers simply to “quebracho” without distinguishing a specific type. Quebracho is most commonly used in industry as a method to separate fluorite from calcite, which is traditionally quite challenging as both minerals share a common ion—calcium. Other applications for quebracho in flotation with calcite minerals as the main gangue source include barite and scheelite. In sulfide systems, quebracho is a key reagent in differential flotation of copper, lead, zinc circuits. The use of quebracho in the precipitation of germanium from zinc ores and for the recovery of ultrafine gold is also detailed in this work. This analysis explores the wide range of uses and methodology of quebracho in the extractive metallurgy field and expands on previous research by Iskra and Kitchener at Imperial College entitled, “Quebracho in Mineral Processing”.

Actinide metal processing

International Nuclear Information System (INIS)

Sauer, N.N.; Watkin, J.G.

1992-01-01

A process for converting an actinide metal such as thorium, uranium, or plutonium to an actinide oxide material by admixing the actinide metal in an aqueous medium with a hypochlorite as an oxidizing agent for sufficient time to form the actinide oxide material and recovering the actinide oxide material is described together with a low temperature process for preparing an actinide oxide nitrate such as uranyl nitrate. Additionally, a composition of matter comprising the reaction product of uranium metal and sodium hypochlorite is provided, the reaction product being an essentially insoluble uranium oxide material suitable for disposal or long term storage

Effect of sonication on particle dispersion, administered dose and metal release of non-functionalized, non-inert metal nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Pradhan, Sulena; Hedberg, Jonas, E-mail: jhed@kth.se; Blomberg, Eva [KTH Royal Institute of Technology, Division of Surface and Corrosion Science, Department of Chemistry (Sweden); Wold, Susanna [KTH Royal Institute of Technology, Division of Applied Physical Chemistry, Department of Chemistry (Sweden); Odnevall Wallinder, Inger [KTH Royal Institute of Technology, Division of Surface and Corrosion Science, Department of Chemistry (Sweden)

2016-09-15

In this study, we elucidate the effect of different sonication techniques to efficiently prepare particle dispersions from selected non-functionalized NPs (Cu, Al, Mn, ZnO), and corresponding consequences on the particle dose, surface charge and release of metals. Probe sonication was shown to be the preferred method for dispersing non-inert, non-functionalized metal NPs (Cu, Mn, Al). However, rapid sedimentation during sonication resulted in differences between the real and the administered doses in the order of 30–80 % when sonicating in 1 and 2.56 g/L NP stock solutions. After sonication, extensive agglomeration of the metal NPs resulted in rapid sedimentation of all particles. DLVO calculations supported these findings, showing the strong van der Waals forces of the metal NPs to result in significant NP agglomeration. Metal release from the metal NPs was slightly increased by increased sonication. The addition of a stabilizing agent (bovine serum albumin) had an accelerating effect on the release of metals in sonicated solutions. For Cu and Mn NPs, the extent of particle dissolution increased from <1.6 to ~5 % after sonication for 15 min. A prolonged sonication time (3–15 min) had negligible effects on the zeta potential of the studied NPs. In all, it is shown that it is of utmost importance to carefully investigate how sonication influences the physico-chemical properties of dispersed metal NPs. This should be considered in nanotoxicology investigations of metal NPs.Graphical Abstract.

Recovering byproduct heavy minerals from sand and gravel, placer gold, and industrial mineral operations

Energy Technology Data Exchange (ETDEWEB)

Gomes, J.M.; Martinez, G.M.; Wong, M.M.

1979-01-01

The Bureau of Mines, as part of an effort to maximize minerals and metals recovery from domestic resources, has investigated the feasibility of recovering heavy minerals as byproducts from sand and gravel, placer gold, and industrial mineral operations in northern California. Sand samples from about 50 locations were treated by gravity separation to yield heavy-mineral cocentrates (black sands). Mineral compositions of the concentrates were determined by chemical analysis and mineralogical examination. Individual zircon, ilmenite, magnetite, platinum-group metals, thoria, and silica products were prepared from heavy-mineral concentrates by selective separation using low- and high-intensity magnetic, high-tension, and flotation equipment.

Secondary defects in non-metallic solids

International Nuclear Information System (INIS)

Ashbee, K.H.G.; Hobbs, L.W.

1977-01-01

This paper points out features of secondary defect formation which are peculiar to non-metallic solids (excluding elemental semiconductors). Most of the materials of interest are compounds of two or more (usually more or less ionic) atomic species, and immediate consequence of which is a need to maintain both stoichiometry (or accommodate non-stoichiometry) and order. Primary defects in these solids, whether produced thermally, chemically or by irradiation, seldom are present or aggregate in exactly stoichiometric proportions, and the resulting extending defect structures can be quite distinct from those found in metallic solids. Where stoichiometry is maintained, it is often convenient to describe extended defects in terms of alterations in the arrangement of 'molecular' units. The adoption of this procedure enables several novel features of extended defect structures in non-metals to be explained. There are several ways in which a range of non-stoichiometry can be accommodated, which include structural elimination of point defects, nucleation of new coherent phases of altered stoichiometry, and decomposition. (author)

The Early Jurassic Bokan Mountain peralkaline granitic complex (southeastern Alaska): geochemistry, petrogenesis and rare-metal mineralization

Science.gov (United States)

Dostal, Jaroslav; Kontak, Daniel J.; Karl, Susan M.

2014-01-01

The Early Jurassic (ca. 177 Ma) Bokan Mountain granitic complex, located on southern Prince of Wales Island, southernmost Alaska, cross-cuts Paleozoic igneous and metasedimentary rocks of the Alexander terrane of the North American Cordillera and was emplaced during a rifting event. The complex is a circular body (~3 km in diameter) of peralkaline granitic composition that has a core of arfvedsonite granite surrounded by aegirine granite. All the rock-forming minerals typically record a two-stage growth history and aegirine and arfvedsonite were the last major phases to crystalize from the magma. The Bokan granites and related dikes have SiO2 from 72 to 78 wt. %, high iron (FeO (tot) ~3-4.5 wt. %) and alkali (8-10 wt.%) concentrations with high FeO(tot)/(FeO(tot)+MgO) ratios (typically >0.95) and the molar Al2O3/(Na2O+K2O) ratio Nd values which are indicative of a mantle signature. The parent magma is inferred to be derived from an earlier metasomatized lithospheric mantle by low degrees of partial melting and generated the Bokan granitic melt through extensive fractional crystallization. The Bokan complex hosts significant rare-metal (REE, Y, U, Th, Nb) mineralization that is related to the late-stage crystallization history of the complex which involved the overlap of emplacement of felsic dikes, including pegmatite bodies, and generation of orthomagmatic fluids. The abundances of REE, HFSE, U and Th as well as Pb and Nd isotopic values of the pluton and dikes were modified by orthomagmatic hydrothermal fluids highly enriched in the strongly incompatible trace elements, which also escaped along zones of structural weakness to generate rare-metal mineralization. The latter was deposited in two stages: the first relates to the latest stage of magma emplacement and is associated with felsic dikes that intruded along the faults and shear deformations, whereas the second stage involved ingress of hydrothermal fluids that both remobilized and enriched the initial

Mineral statistics yearbook 1994

International Nuclear Information System (INIS)

1994-01-01

A summary of mineral production in Saskatchewan was compiled and presented as a reference manual. Statistical information on fuel minerals such as crude oil, natural gas, liquefied petroleum gas and coal, and of industrial and metallic minerals, such as potash, sodium sulphate, salt and uranium, was provided in all conceivable variety of tables. Production statistics, disposition and value of sales of industrial and metallic minerals were also made available. Statistical data on drilling of oil and gas reservoirs and crown land disposition were also included. figs., tabs

Survey on basic data of risk estimation of lung cancer among non-uranium miners in China

International Nuclear Information System (INIS)

Fu Yinghua; Sun Quanfu; Du Weixia; Lei Suwen; Lei Shujie; Li Xiaoying; Zhang Shouzhi; Qian Yekan; Su Xu

2009-01-01

Objective: To investigate the basic data of risk estimation of lung cancer among non-uranium miners in China. Methods: 2836 workers from 24 mines in 9 provinces/regions were face-to-face interviewed to collect information including age at exposure,exposure duration, cigarette smoking among others. Results: Age of the investigated non-uranium miners ranged from 17 to 72 (36.9 ± 8.0) years. The miners received low and poor education, 3% of them were illiterate, 58% with primary and middle school education, only 7% with junior college and higher education. Seventy-five percent of the uranium miners are migrant rural workers. Ethnic minority miners accoungted for 16% of all the investigated miners. Among the migrant rural workers age at initial exposure was estimated to be 29.6 ± 8.0 years. By the time of the investigation, 46.7% of the miners had worked in the mine for five years and longer, working years in the mine was 6.7 ± 6.8 years with a median of 4.1 years. 3.4% of the non-uranium miners began the initial radon exposure in mines before their 18 years of old. 17.5% of the investigated miners reported working more than 8 h every working day. Among the males, 58.0% were current smokers with a median of 16 cigarettes per day. Age to begin the cigarette smoking was 20 years on average. Current smoking rate was age-dependent, the rate as high as 69.2% for the males aged 15-19 years. Current smoking rate was significantly statistically lower in coal mines than that in other mines, 49.0% vs 62.5%. Compared with other miners, more frequent mechanical ventilations were reported by coal miners, Conclusions: In China non-uranium mines, 75% were migrant rural workers, by the time of the investigation about half of them had worked in the mines for at least five years. Non-uranium miners began their mining at 30 years on average, with a very small percentage of 3%, exposed to the mining radon before their 18 years. Current cigarette smoking rate in non-uranium male miners

Advanced metal lift-off process using electron-beam flood exposure of single-layer photoresist

Science.gov (United States)

Minter, Jason P.; Ross, Matthew F.; Livesay, William R.; Wong, Selmer S.; Narcy, Mark E.; Marlowe, Trey

1999-06-01

In the manufacture of many types of integrated circuit and thin film devices, it is desirable to use a lift-of process for the metallization step to avoid manufacturing problems encountered when creating metal interconnect structures using plasma etch. These problems include both metal adhesion and plasma etch difficulties. Key to the success of the lift-off process is the creation of a retrograde or undercut profile in the photoresists before the metal deposition step. Until now, lift-off processing has relied on costly multi-layer photoresists schemes, image reversal, and non-repeatable photoresist processes to obtain the desired lift-off profiles in patterned photoresist. This paper present a simple, repeatable process for creating robust, user-defined lift-off profiles in single layer photoresist using a non-thermal electron beam flood exposure. For this investigation, lift-off profiles created using electron beam flood exposure of many popular photoresists were evaluated. Results of lift-off profiles created in positive tone AZ7209 and ip3250 are presented here.

Geological structure and prospects of noble metal ore mineralization of the Khayrkhan gabbroid massif (Western Mongolia)

Science.gov (United States)

Kurumshieva, K. R.; Gertner, I. F.; Tishin, P. A.

2017-12-01

An analysis of the distribution of noble metals in zones of sulfide mineralization makes it possible to justify the isolation of four ore-bearing horizons with a specific geochemical zonation. A rise in the gold content relative to palladium and platinum is observed from the bottom upwards along the section of the stratified series of gabbroids. The study of the mineral phases of sulphides and the noble minerals itself indicates the evolution of hydrothermal solutions, which determines the different activity and mobility of the fluid (mercury, tellurium, sulfur) and ore (copper, nickel, iron, platinum, gold and silver) components.

Bio-mineralization and potential biogeochemical processes in bauxite deposits: genetic and ore quality significance

Science.gov (United States)

Laskou, Magdalini; Economou-Eliopoulos, Maria

2013-08-01

The Parnassos-Ghiona bauxite deposit in Greece of karst type is the 11th largest bauxite producer in the world. The mineralogical, major and trace-element contents and δ18O, δ12C, δ34S isotopic compositions of bauxite ores from this deposit and associated limestone provide valuable evidence for their origin and biogeochemical processes resulting in the beneficiation of low grade bauxite ores. The organic matter as thin coal layers, overlying the bauxite deposits, within limestone itself (negative δ12C isotopic values) and the negative δ34S values in sulfides within bauxite ores point to the existence of the appropriate circumstances for Fe bio-leaching and bio-mineralization. Furthermore, a consortium of microorganisms of varying morphological forms (filament-like and spherical to lenticular at an average size of 2 μm), either as fossils or presently living and producing enzymes, is a powerful factor to catalyze the redox reactions, expedite the rates of metal extraction and provide alternative pathways for metal leaching processes resulting in the beneficiation of bauxite ore.

Method for decontaminating radiation metal waste

International Nuclear Information System (INIS)

Onuma, Tsutomu; Tanaka, Akio; Akimoto, Hidetoshi

1991-01-01

This report describes a method for decontaminating radiation metal waste characterized by the following properties: in order to decontaminate radiation metal waste of various shapes produced by facilities involved with radioactive substances, non-complex shapes are decontaminated by electropolishing the materials in a neutral saline solution. Complex shapes are chemically decontaminated by means of an acid solution containing permanganic acid or an alkaline solution and a mineral acid solution. After neutralizing the solutions used for chemical decontamination, the radioactive material is separated and removed. Further, in the decontamination method for radioactive metal waste, a supernatant liquid is reused as the electrolyte in electropolishing decontamination. Permanganic ions (MnO 4 - ) are reduced to manganese dioxide (MnO 2 ) and deposited prior to neutralizing the solution used for chemical decontamination. Once manganese dioxide (MnO 2 ) has been separated and removed, it is re-used as the electrolyte in electropolishing decontamination by means of a process identical to the separation process for radioactive substances. 3 figs

Autoradiographic investigation of the removal of non-metallic inclusions in connection with the steel remelting process in vacuum furnaces

International Nuclear Information System (INIS)

Kolaski, H.; Siewierski, J.

1978-01-01

The labelled radioactive non-metallic inclusions in steel were obtained through deoxidation of steel with an activated aluminium alloy containing 1% rare earths. Quantity and distribution of the non-metallic inclusions in the steel were determined by applying autoradiography to the longitudinal and cross sections of the steel slabs. After remelting in an electronic furnace the distribution of non-metallic inclusions was determined by autoradiography of the lateral surfaces and the cross section of the slabs. It was found that 50 - 70% of the inclusions could be removed. The results obtained from autoradiographic investigation allow the exploration of the mechanism of the removal of inclusions. (author)

Process, structure, property and applications of metallic glasses

Directory of Open Access Journals (Sweden)

B. Geetha Priyadarshini

2016-07-01

Full Text Available Metallic glasses (MGs are gaining immense technological significance due to their unique structure-property relationship with renewed interest in diverse field of applications including biomedical implants, commercial products, machinery parts, and micro-electro-mechanical systems (MEMS. Various processing routes have been adopted to fabricate MGs with short-range ordering which is believed to be the genesis of unique structure. Understanding the structure of these unique materials is a long-standing unsolved mystery. Unlike crystalline counterpart, the outstanding properties of metallic glasses owing to the absence of grain boundaries is reported to exhibit high hardness, excellent strength, high elastic strain, and anti-corrosion properties. The combination of these remarkable properties would significantly contribute to improvement of performance and reliability of these materials when incorporated as bio-implants. The nucleation and growth of metallic glasses is driven by thermodynamics and kinetics in non-equilibrium conditions. This comprehensive review article discusses the various attributes of metallic glasses with an aim to understand the fundamentals of relationship process-structure-property existing in such unique class of material.

Application of hydrometallurgy techniques in quartz processing and purification: a review

Science.gov (United States)

Lin, Min; Lei, Shaomin; Pei, Zhenyu; Liu, Yuanyuan; Xia, Zhangjie; Xie, Feixiang

2018-04-01

Although there have been numerous studies on separation and purification of metallic minerals by hydrometallurgy techniques, applications of the chemical techniques in separation and purification of non-metallic minerals are rarely reported. This paper reviews disparate areas of study into processing and purification of quartz (typical non-metallic ore) in an attempt to summarize current work, as well as to suggest potential for future consolidation in the field. The review encompasses chemical techniques of the quartz processing including situations, progresses, leaching mechanism, scopes of application, advantages and drawbacks of micro-bioleaching, high temperature leaching, high temperature pressure leaching and catalyzed high temperature pressure leaching. Traditional leaching techniques including micro-bioleaching and high temperature leaching are unequal to demand of modern glass industry for quality of quartz concentrate because the quartz products has to be further processed. High temperature pressure leaching and catalyzed high temperature pressure leaching provide new ways to produce high-grade quartz sand with only one process and lower acid consumption. Furthermore, the catalyzed high temperature pressure leaching realizes effective purification of quartz with extremely low acid consumption (no using HF or any fluoride). It is proposed that, by integrating the different chemical processes of quartz processing and expounding leaching mechanisms and scopes of application, the research field as a monopolized industry would benefit.

Pretreatment process for mineral analysis in FFH using INAA-method and evaluation of mineral intakes

International Nuclear Information System (INIS)

Lee, Ok Hee; Youn, Kyung Jin; Lee, Ji Bum; Kim, Mi Jin

2010-05-01

This study were aimed to set up the pre-treatment process for FFH and analyse Pretreatment processes for the analysis of food mineral contents by INAA were established according to FFH state using freeze-drying and homogenization. The Se contents showed higher precision with INAA-method than ICP-method. The content of Ca, Na, Mg, Fe, Zn, Cu, Mn, Cr, Co in FFH measured using INAA-method showed that the mineral contents in the amount of recommended intakes by manufacturer were not significantly different according to FFH type. The average Ca contents was the highest in Yousanguns > nutritional supplement> glucosamines. The average K content of FFH with one serving size were the highest in glucosamines>aloes> nutritional supplements. I content among FFH was the highest in nutritional supplements. The average Mg contents were highest in Chlorella-Spirurina and Aloes. The average Cu content of FFH was the highest in Yeasts. The contents of Fe, Zn and Se were the highest in nutritional supplements. The mineral contents in recommended intake amounts by manufacturer were over the maximum contents regulated by Korean FDA in some imported FFH products. their mineral contents of FFH using NAA-method and to assess the mineral intakes by FFH

Pretreatment process for mineral analysis in FFH using INAA-method and evaluation of mineral intakes

Energy Technology Data Exchange (ETDEWEB)

Lee, Ok Hee; Youn, Kyung Jin; Lee, Ji Bum; Kim, Mi Jin [Yongin University, Yongin (Korea, Republic of)

2010-05-15

This study were aimed to set up the pre-treatment process for FFH and analyse Pretreatment processes for the analysis of food mineral contents by INAA were established according to FFH state using freeze-drying and homogenization. The Se contents showed higher precision with INAA-method than ICP-method. The content of Ca, Na, Mg, Fe, Zn, Cu, Mn, Cr, Co in FFH measured using INAA-method showed that the mineral contents in the amount of recommended intakes by manufacturer were not significantly different according to FFH type. The average Ca contents was the highest in Yousanguns > nutritional supplement> glucosamines. The average K content of FFH with one serving size were the highest in glucosamines>aloes> nutritional supplements. I content among FFH was the highest in nutritional supplements. The average Mg contents were highest in Chlorella-Spirurina and Aloes. The average Cu content of FFH was the highest in Yeasts. The contents of Fe, Zn and Se were the highest in nutritional supplements. The mineral contents in recommended intake amounts by manufacturer were over the maximum contents regulated by Korean FDA in some imported FFH products. their mineral contents of FFH using NAA-method and to assess the mineral intakes by FFH

Proceedings of the 40. annual meeting of the Canadian Mineral Processors : 2008

Energy Technology Data Exchange (ETDEWEB)

Orford, I. [AMEC, Oakville, ON (Canada)] (comp.)

2008-07-01

This conference addressed a broad range of issues affecting the minerals and metals sector, with particular reference to advances in technology that continue to improve mineral processing. Innovative, high efficiency mineral extraction processes were presented along with process analysis methods and advanced control systems. In addition to a plenary session, the conference featured the following 8 sessions: (1) plant improvements, (2) plant design and comminution, (3) mineral separation, (4) dewatering and flotation, (5) flotation, (6) instrumentation and process control, (7) hydrometallurgy and gold, and (8) gold. One of the 36 presentations featured at this conference has been catalogued separately for inclusion in this database. refs., tabs., figs.

Thermomagnetic identification of manganese and iron minerals present in soils and industrial dusts

Science.gov (United States)

Wawer, Małgorzata; Rachwał, Marzena; Jabłońska, Mariola; Krzykawski, Tomasz; Magiera, Tadeusz

2017-04-01

Many industries (e.g. metallurgy, power, cement, and coking plants) constitute a sources of industrial dusts containing technogenic magnetic particles (TMP). TMP are mostly iron oxides with ferrimagnetic or antiferromagnetic properties, therefore their presence in dusts, soils and sediments can be easily detected by magnetic susceptibility measurements. TMP, thanks their specific mineral and magnetic properties, and well developed specific surface area, are characterized by a chemical affinity for some elements like heavy metals. The main objective of this study was identification of manganese and iron (hydro)oxides occurring in industrial dusts and soils being under their deposition for long time period. In principle, Mn and Fe (hydro)oxides present in these samples originate from high-temperature technological processes. Soils samples (collected from different soil horizons) taken from surroundings of power station, iron/steel and non-ferrous plants as well as metallurgical dusts and fly ashes from power stations were subjected to investigation. During the studies temperature dependent magnetic susceptibility measurements and X-ray powder diffraction analyses were applied. Thermomagnetic analyses (K-T) revealed differences between samples from particular industries, however an inflexion at 450-500°C of all curves was observed indicating a probable occurrence of maghemite- or titanomagnetite-like phases. The curves of TMP emitted by power plants have inflection at 580 °C indicating that magnetite was the main magnetic phase. In case of TMP originated from non-ferrous metal smelting additional curve deflection at 130 and 210 °C occurred relating to intermediate titanomagnetite or iron sulfides. X-ray diffraction proved the occurrence of magnetite and maghemite in almost all samples, especially connected with power industry and iron/steel metallurgy. Mineral analysis revealed that kind of industrial process influenced on the dominating mineral forms found in

Treatment of transverse patellar fractures: a comparison between metallic and non-metallic implants.

Science.gov (United States)

Heusinkveld, Maarten H G; den Hamer, Anniek; Traa, Willeke A; Oomen, Pim J A; Maffulli, Nicola

2013-01-01

Several methods of transverse patellar fixation have been described. This study compares the clinical outcome and the occurrence of complications of various fixation methods. The databases PubMed, Web of Science, Science Direct, Google Scholar and Google were searched. A direct comparison between fixation techniques using mixed or non-metallic implants and metallic K-wire and tension band fixation shows no significant difference in clinical outcome between both groups. Additionally, studies reporting novel operation techniques show good clinical results. Studies describing the treatment of patients using non-metallic or mixed implants are fewer compared with those using metallic fixation. A large variety of clinical scoring systems were used for assessing the results of treatment, which makes direct comparison difficult. More data of fracture treatment using non-metallic or mixed implants is needed to achieve a more balanced comparison.

Implementation and application of a method for quantifying metals and non-metals in drainage water from soils fertilized with phosphogypsum

International Nuclear Information System (INIS)

Silva, Camila Goncalves Bof

2010-01-01

Phosphogypsum is a waste generated in phosphoric acid production by the 'wet process'. The immense amount of phosphogypsum yearly produced (around 150 million tons) is receiving attention from environmental protection agencies all over the word, given its potential of contamination. In Brazil, this material has been used for many decades, especially for agricultural application on cropland. Although the phosphogypsum is mainly composed of dehydrated calcium sulfate, it can have high levels of impurities, such as metals (Cd, Cr, Cu, Pb), non-metals (As and Se) and radioactive elements from natural series of 232 Th and 238 U. Therefore, its continuous application as an agricultural agent can result not just in soil contamination, but also contamination of the surface and groundwater due to the runoff and infiltration process. The concern associated with the contamination of aquatic environments increases; when water is used for human consumption, requiring progressive adoption of more restrictive limits. However, some of the conventional analytical techniques used to determine the maximum limit of contaminants in water have detection limits above the maximum limits established by the environmental legislation. This work was aimed to evaluate the mobility of metals and non-metals in soils and, consequently, the contamination of drainage water through greenhouse-scale leaching and transport of toxic elements from soils fertilized with phosphogypsum. Hence, methods were studied and implemented for determination of metals (Cd, Cr, Cu and Pb) using Furnace Graphite Atomic Absorption Spectrometry (GF AAS), as well as for non-metals (As and Se) using Inductively Coupled Plasma Mass Spectrometry (lCP-MS). Effects of different chemical modifiers on the determination of Cd, Cr, Cu and Pb concentration by GF AAS were also investigated. In general, it was observed that the metal and non-metal concentration were below than the actual detection limit of the equipment for all

Innovation processes in technologies for the processing of refractory mineral raw materials

Science.gov (United States)

Chanturiya, V. A.

2008-12-01

Analysis of the grade of mineral resources of Russia and other countries shows that end products that are competitive in terms of both technological and environmental criteria in the world market can only be obtained by the development and implementation of progressive technologies based on the up-to-date achievements of fundamental sciences. The essence of modern innovation processes in technologies developed in Russia for the complex and comprehensive processing of refractory raw materials with a complex composition is ascertained. These processes include (i) radiometric methods of concentration of valuable components, (ii) high-energy methods of disintegration of highly dispersed mineral components, and (iii) electrochemical methods of water conditioning to obtain target products for solving specific technological problems.

Metal-organic molecular device for non-volatile memory storage

International Nuclear Information System (INIS)

Radha, B.; Sagade, Abhay A.; Kulkarni, G. U.

2014-01-01

Non-volatile memory devices have been of immense research interest for their use in active memory storage in powered off-state of electronic chips. In literature, various molecules and metal compounds have been investigated in this regard. Molecular memory devices are particularly attractive as they offer the ease of storing multiple memory states in a unique way and also represent ubiquitous choice for miniaturized devices. However, molecules are fragile and thus the device breakdown at nominal voltages during repeated cycles hinders their practical applicability. Here, in this report, a synergetic combination of an organic molecule and an inorganic metal, i.e., a metal-organic complex, namely, palladium hexadecylthiolate is investigated for memory device characteristics. Palladium hexadecylthiolate following partial thermolysis is converted to a molecular nanocomposite of Pd(II), Pd(0), and long chain hydrocarbons, which is shown to exhibit non-volatile memory characteristics with exceptional stability and retention. The devices are all solution-processed and the memory action stems from filament formation across the pre-formed cracks in the nanocomposite film.

Mineral industry in Australia

International Nuclear Information System (INIS)

Parbo, S.A.

1982-01-01

The paper reviews the history and growth of the mineral industry in Australia and its significance to the nation's economic growth and overseas trade, particularly over the last twenty years during which time production of coal, iron ore, manganese and mineral sands has increased greatly and new discoveries of petroleum, bauxite and nickel have given rise to major new industries. Australia ranks fourteenths in the value of world trade and is among the world's largest exporters of alumina, iron ore, mineral sands, coal, lead, zinc and nickel. Some details of production, processing and exports of the major minerals are given. Comment is made on the policies and roles of the six State Governments and the Federal Government in respect of ownership and control of the mining, processing and exporting of both energy and non-energy minerals. (orig.) [de

Process and apparatus for distilling bituminous minerals

Energy Technology Data Exchange (ETDEWEB)

Veyrier, J A

1922-03-27

This process of distillation of bituminous minerals and particularly bituminous limestone is characterized by the fact that the minerals are introduced into the retort where they stand only the temperature necessary to distill the water and lighter oils that they contain and then are drawn out into the hearth and serve for heating the retort. The apparatus is characterized by the fact that the retort has a screw conveyor, placed in the flue of the hearth, supplied with a chamber for evacuation below this hearth.

Online differentiation of mineral phase in aerosol particles by ion formation mechanism using a LAAP-TOF single-particle mass spectrometer

Science.gov (United States)

Marsden, Nicholas A.; Flynn, Michael J.; Allan, James D.; Coe, Hugh

2018-01-01

Mineralogy of silicate mineral dust has a strong influence on climate and ecosystems due to variation in physiochemical properties that result from differences in composition and crystal structure (mineral phase). Traditional offline methods of analysing mineral phase are labour intensive and the temporal resolution of the data is much longer than many atmospheric processes. Single-particle mass spectrometry (SPMS) is an established technique for the online size-resolved measurement of particle composition by laser desorption ionisation (LDI) followed by time-of-flight mass spectrometry (TOF-MS). Although non-quantitative, the technique is able to identify the presence of silicate minerals in airborne dust particles from markers of alkali metals and silicate molecular ions in the mass spectra. However, the differentiation of mineral phase in silicate particles by traditional mass spectral peak area measurements is not possible. This is because instrument function and matrix effects in the ionisation process result in variations in instrument response that are greater than the differences in composition between common mineral phases.In this study, we introduce a novel technique that enables the differentiation of mineral phase in silicate mineral particles by ion formation mechanism measured from subtle changes in ion arrival times at the TOF-MS detector. Using a combination of peak area and peak centroid measurements, we show that the arrangement of the interstitial alkali metals in the crystal structure, an important property in silicate mineralogy, influences the ion arrival times of elemental and molecular ion species in the negative ion mass spectra. A classification scheme is presented that allowed for the differentiation of illite-smectite, kaolinite and feldspar minerals on a single-particle basis. Online analysis of mineral dust aerosol generated from clay mineral standards produced mineral fractions that are in agreement with bulk measurements reported by

Mechanism of radiation and thermal decomposition of sulphide non-ferrous metals

International Nuclear Information System (INIS)

Mazhrenova, N.P.

1998-01-01

This paper deals with the non-ferrous metals sulfides in term of their radiative sensitivity, directed chances of their physical-chemical, and hence technological properties by radiation influence both on sulfide materials and on the processes with their participation. (author)

Model Predictive Control of Mineral Column Flotation Process

Directory of Open Access Journals (Sweden)

Yahui Tian

2018-06-01

Full Text Available Column flotation is an efficient method commonly used in the mineral industry to separate useful minerals from ores of low grade and complex mineral composition. Its main purpose is to achieve maximum recovery while ensuring desired product grade. This work addresses a model predictive control design for a mineral column flotation process modeled by a set of nonlinear coupled heterodirectional hyperbolic partial differential equations (PDEs and ordinary differential equations (ODEs, which accounts for the interconnection of well-stirred regions represented by continuous stirred tank reactors (CSTRs and transport systems given by heterodirectional hyperbolic PDEs, with these two regions combined through the PDEs’ boundaries. The model predictive control considers both optimality of the process operations and naturally present input and state/output constraints. For the discrete controller design, spatially varying steady-state profiles are obtained by linearizing the coupled ODE–PDE model, and then the discrete system is obtained by using the Cayley–Tustin time discretization transformation without any spatial discretization and/or without model reduction. The model predictive controller is designed by solving an optimization problem with input and state/output constraints as well as input disturbance to minimize the objective function, which leads to an online-solvable finite constrained quadratic regulator problem. Finally, the controller performance to keep the output at the steady state within the constraint range is demonstrated by simulation studies, and it is concluded that the optimal control scheme presented in this work makes this flotation process more efficient.

Acid extraction of molybdenum, nickel and cobalt from mineral sludge generated by rainfall water at a metal recycling plant.

Science.gov (United States)

Vemic, M; Bordas, F; Guibaud, G; Comte, S; Joussein, E; Lens, P N L; Van Hullebusch, E D

2016-01-01

This study investigated the leaching yields of Mo, Ni and Co from a mineral sludge of a metal recycling plant generated by rainfalls. The investigated mineral sludge had a complex heterogeneous composition, consisting of particles of settled soil combined with metal-bearing particles (produced by catalysts, metallic oxides and battery recycling). The leaching potential of different leaching reagents (stand-alone strong acids (HNO3 (68%), H2SO4 (98%) and HCl (36%)) and acid mixtures (aqua regia (nitric + hydrochloric (1:3)), nitric + sulphuric (1:1) and nitric + sulphuric + hydrochloric (2:1:1)) was investigated at changing operational parameters (solid-liquid (S/L) ratio, leaching time and temperature), in order to select the leaching reagent which achieves the highest metal leaching yields. Sulphuric acid (98% H2SO4) was found to be the leachant with the highest metal leaching potential. The optimal leaching conditions were a three-stage successive leaching at 80 °C with a leaching time of 2 h and S/L ratio of 0.25 g L(-1). Under these conditions, the achieved mineral sludge sample leaching yields were 85.5%, 40.5% and 93.8% for Mo, Ni and Co, respectively. The higher metal leaching potential of H2SO4 in comparison with the other strong acids/acid mixtures is attributed to the fact that H2SO4 is a diacidic compound, thus it has more H(+) ions, resulting in its stronger oxidizing power and corrosiveness.

Characterization of Mongolian Natural Minerals and Their Application for Heavy Metal Adsorbent

OpenAIRE

Dolgormaa, Munkhbat; Shiomori, Koichiro; Bayanjargal, Ochirkhuyag

2016-01-01

In this study, the structural characteristic and the adsorption properties of heavy metals on Mongolian natural minerals were investigated. The natural samples were confirmed as Heulandite group of Clinoptilolite type zeolite and clay sample that contains albite and quartz by X-ray diffraction analysis. According to BET surface analysis, natural zeolites have mesoporous type of pore. The results of adsorption study showed that adsorption ability of natural zeolite is high effective for lead i...

Incidence of non-lung solid cancers in Czech uranium miners: A case-cohort study

International Nuclear Information System (INIS)

Kulich, M.; Rericha, V.; Rericha, R.; Shore, D.L.; Sandler, D.P.

2011-01-01

Objectives: Uranium miners are chronically exposed to radon and its progeny, which are known to cause lung cancer and may be associated with leukemia. This study was undertaken to evaluate risk of non-lung solid cancers among uranium miners in Pribram region, Czech Republic. Methods: A retrospective stratified case-cohort study in a cohort of 22,816 underground miners who were employed between 1949 and 1975. All incident non-lung solid cancers were ascertained among miners who worked underground for at least 12 months (n=1020). A subcohort of 1707 subjects was randomly drawn from the same population by random sampling stratified on age. The follow-up period lasted from 1977 to 1996. Results: Relative risks comparing 180 WLM (90th percentile) of cumulative lifetime radon exposure to 3 WLM (10th percentile) were 0.88 for all non-lung solid cancers combined (95% CI 0.73-1.04, n=1020), 0.87 for all digestive cancers (95% CI 0.69-1.09, n=561), 2.39 for gallbladder cancer (95% CI 0.52-10.98, n=13), 0.79 for larynx cancer (95% CI 0.38-1.64, n=62), 2.92 for malignant melanoma (95% CI 0.91-9.42, n=23), 0.84 for bladder cancer (95% CI 0.43-1.65, n=73), and 1.13 for kidney cancer (95% CI 0.62-2.04, n=66). No cancer type was significantly associated with radon exposure; only malignant melanoma and gallbladder cancer showed elevated but non-significant association with radon. Conclusions: Radon was not significantly associated with incidence of any cancer of interest, although a positive association of radon with malignant melanoma and gallbladder cancer cannot be entirely ruled out. - Research highlights: → Uranium miners are chronically exposed to radon. → We evaluate risk of non-lung solid cancers among uranium miners. → No cancer type was significantly associated with radon exposure. → Malignant melanoma and gallbladder cancer showed non-significant elevated risk.

Arc plasma assisted rotating electrode process for preparation of metal pebbles

International Nuclear Information System (INIS)

Mohanty, T.; Tripathi, B.M.; Mahata, T.; Sinha, P.K.

2014-01-01

Spherical beryllium pebbles of size ranging from 0.2-2 mm are required as neutron multiplying material in solid Test Blanket Module (TBM) of International Thermonuclear Experimental Reactor (ITER). Rotating electrode process (REP) has been identified as a suitable technique for preparation of beryllium pebbles. In REP, arc plasma generated between non-consumable electrode (cathode) and rotating metal electrode (anode) plays a major role for continuous consumption of metal electrode and preparation of spherical metal pebbles. This paper focuses on description of the process, selection of sub-systems for development of REP experimental set up and optimization of arc parameters, such as, cathode geometry, arc current, arc voltage, arc gap and carrier gas flow rate for preparation of required size spherical metal pebbles. Other parameters which affect the pebbles sizes are rotational speed, metal electrode diameter and physical properties of the metal. As beryllium is toxic in nature its surrogate metals such as stainless steel (SS) and Titanium (Ti) were selected to evaluate the performance of the REP equipment. Several experiments were carried out using SS and Ti electrode and process parameters have been optimized for preparation of pebbles of different sizes. (author)

Intensification of zinc dissolution process in sulphuric acid

Directory of Open Access Journals (Sweden)

Stanojević D.

2005-01-01

Full Text Available Many high purity salts are produced by dissolving pure metal in non-oxidizing mineral acids. If hydrogen overpotential on the given metal is high, then the rate of overall process is defined by reaction of hydrogen ion reduction. This study investigated the possibility of accelerated dissolving of metal zinc in sulphuric acid by introducing copper cathode on which evolving hydrogen is much easier than on zinc. It was found out that the acceleration of zinc dissolving is possible and, at constant surface of copper cathode depends on the quality of electrical contact between copper electrode and zinc.

Opportunities for membrane technologies in the treatment of mining and mineral process streams and effluents

International Nuclear Information System (INIS)

Awadalla, F.T.; Kumar, A.

1994-01-01

The membrane separation technologies of microfiltration, ultrafiltration, nanofiltration, and reverse osmosis are suitable for treating many dilute streams and effluents generated in mining and mineral processing. Membrane technologies are capable of treating these dilute streams in order to produce clean permeate water for recycle and a concentrate that can potentially be used for valuable metals recovery. Membrane technologies can be utilized alone, or in combination with other techniques as a polishing step, in these separation processes. A review of potential applications of membranes for the treatment of different process streams and effluents for water recycling and pollution control is given here. Although membranes may not be optimum in all applications, these technologies are recognized in the mining sector for the many potential advantages they can provide. 59 refs

Pre-eruptive magmatic processes re-timed using a non-isothermal approach to magma chamber dynamics.

Science.gov (United States)

Petrone, Chiara Maria; Bugatti, Giuseppe; Braschi, Eleonora; Tommasini, Simone

2016-10-05

Constraining the timescales of pre-eruptive magmatic processes in active volcanic systems is paramount to understand magma chamber dynamics and the triggers for volcanic eruptions. Temporal information of magmatic processes is locked within the chemical zoning profiles of crystals but can be accessed by means of elemental diffusion chronometry. Mineral compositional zoning testifies to the occurrence of substantial temperature differences within magma chambers, which often bias the estimated timescales in the case of multi-stage zoned minerals. Here we propose a new Non-Isothermal Diffusion Incremental Step model to take into account the non-isothermal nature of pre-eruptive processes, deconstructing the main core-rim diffusion profiles of multi-zoned crystals into different isothermal steps. The Non-Isothermal Diffusion Incremental Step model represents a significant improvement in the reconstruction of crystal lifetime histories. Unravelling stepwise timescales at contrasting temperatures provides a novel approach to constraining pre-eruptive magmatic processes and greatly increases our understanding of magma chamber dynamics.

Minerals Yearbook, volume III, Area Reports—International—Europe and Central Eurasia

Science.gov (United States)

Geological Survey, U.S.

2018-01-01

The U.S. Geological Survey (USGS) Minerals Yearbook discusses the performance of the worldwide minerals and materials industries and provides background information to assist in interpreting that performance. Content of the individual Minerals Yearbook volumes follows:Volume I, Metals and Minerals, contains chapters about virtually all metallic and industrial mineral commodities important to the U.S. economy. Chapters on survey methods, summary statistics for domestic nonfuel minerals, and trends in mining and quarrying in the metals and industrial mineral industries in the United States are also included.Volume II, Area Reports: Domestic, contains a chapter on the mineral industry of each of the 50 States and Puerto Rico and the Administered Islands. This volume also has chapters on survey methods and summary statistics of domestic nonfuel minerals.Volume III, Area Reports: International, is published as four separate reports. These regional reports contain the latest available minerals data on more than 180 foreign countries and discuss the importance of minerals to the economies of these nations and the United States. Each report begins with an overview of the region’s mineral industries during the year. It continues with individual country chapters that examine the mining, refining, processing, and use of minerals in each country of the region and how each country’s mineral industry relates to U.S. industry. Most chapters include production tables and industry structure tables, information about Government policies and programs that affect the country’s mineral industry, and an outlook section.The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the Minerals Yearbook are welcomed.

Minerals Yearbook, volume III, Area Reports—International—Asia and the Pacific

Science.gov (United States)

Geological Survey, U.S.

2018-01-01

The U.S. Geological Survey (USGS) Minerals Yearbook discusses the performance of the worldwide minerals and materials industries and provides background information to assist in interpreting that performance. Content of the individual Minerals Yearbook volumes follows:Volume I, Metals and Minerals, contains chapters about virtually all metallic and industrial mineral commodities important to the U.S. economy. Chapters on survey methods, summary statistics for domestic nonfuel minerals, and trends in mining and quarrying in the metals and industrial mineral industries in the United States are also included.Volume II, Area Reports: Domestic, contains a chapter on the mineral industry of each of the 50 States and Puerto Rico and the Administered Islands. This volume also has chapters on survey methods and summary statistics of domestic nonfuel minerals.Volume III, Area Reports: International, is published as four separate reports. These regional reports contain the latest available minerals data on more than 180 foreign countries and discuss the importance of minerals to the economies of these nations and the United States. Each report begins with an overview of the region’s mineral industries during the year. It continues with individual country chapters that examine the mining, refining, processing, and use of minerals in each country of the region and how each country’s mineral industry relates to U.S. industry. Most chapters include production tables and industry structure tables, information about Government policies and programs that affect the country’s mineral industry, and an outlook section.The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the Minerals Yearbook are welcomed.

Minerals Yearbook, volume III, Area Reports—International—Latin America and Canada

Science.gov (United States)

,

2018-01-01

The U.S. Geological Survey (USGS) Minerals Yearbook discusses the performance of the worldwide minerals and materials industries and provides background information to assist in interpreting that performance. Content of the individual Minerals Yearbook volumes follows:Volume I, Metals and Minerals, contains chapters about virtually all metallic and industrial mineral commodities important to the U.S. economy. Chapters on survey methods, summary statistics for domestic nonfuel minerals, and trends in mining and quarrying in the metals and industrial mineral industries in the United States are also included.Volume II, Area Reports: Domestic, contains a chapter on the mineral industry of each of the 50 States and Puerto Rico and the Administered Islands. This volume also has chapters on survey methods and summary statistics of domestic nonfuel minerals.Volume III, Area Reports: International, is published as four separate reports. These regional reports contain the latest available minerals data on more than 180 foreign countries and discuss the importance of minerals to the economies of these nations and the United States. Each report begins with an overview of the region’s mineral industries during the year. It continues with individual country chapters that examine the mining, refining, processing, and use of minerals in each country of the region and how each country’s mineral industry relates to U.S. industry. Most chapters include production tables and industry structure tables, information about Government policies and programs that affect the country’s mineral industry, and an outlook section.The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the Minerals Yearbook are welcomed.

Extraction process for removing metallic impurities from alkalide metals

Science.gov (United States)

Royer, Lamar T.

1988-01-01

A development is described for removing metallic impurities from alkali metals by employing an extraction process wherein the metallic impurities are extracted from a molten alkali metal into molten lithium metal due to the immiscibility of the alkali metals in lithium and the miscibility of the metallic contaminants or impurities in the lithium. The purified alkali metal may be readily separated from the contaminant-containing lithium metal by simple decanting due to the differences in densities and melting temperatures of the alkali metals as compared to lithium.

Online differentiation of mineral phase in aerosol particles by ion formation mechanism using a LAAP-TOF single-particle mass spectrometer

Directory of Open Access Journals (Sweden)

N. A. Marsden

2018-01-01

Full Text Available Mineralogy of silicate mineral dust has a strong influence on climate and ecosystems due to variation in physiochemical properties that result from differences in composition and crystal structure (mineral phase. Traditional offline methods of analysing mineral phase are labour intensive and the temporal resolution of the data is much longer than many atmospheric processes. Single-particle mass spectrometry (SPMS is an established technique for the online size-resolved measurement of particle composition by laser desorption ionisation (LDI followed by time-of-flight mass spectrometry (TOF-MS. Although non-quantitative, the technique is able to identify the presence of silicate minerals in airborne dust particles from markers of alkali metals and silicate molecular ions in the mass spectra. However, the differentiation of mineral phase in silicate particles by traditional mass spectral peak area measurements is not possible. This is because instrument function and matrix effects in the ionisation process result in variations in instrument response that are greater than the differences in composition between common mineral phases.In this study, we introduce a novel technique that enables the differentiation of mineral phase in silicate mineral particles by ion formation mechanism measured from subtle changes in ion arrival times at the TOF-MS detector. Using a combination of peak area and peak centroid measurements, we show that the arrangement of the interstitial alkali metals in the crystal structure, an important property in silicate mineralogy, influences the ion arrival times of elemental and molecular ion species in the negative ion mass spectra. A classification scheme is presented that allowed for the differentiation of illite–smectite, kaolinite and feldspar minerals on a single-particle basis. Online analysis of mineral dust aerosol generated from clay mineral standards produced mineral fractions that are in agreement with bulk

Minerals in deserts

International Nuclear Information System (INIS)

Smith, G.I.

1982-01-01

Almost any kind of mineral deposit can occur in desert areas, and the lack of vegetation and soil cover makes finding them easier. Some kinds of deposits, though, are more likely to occur in deserts than elsewhere. Some of these result from processes genetically related to the present desert climate that improved lower grade deposits of ore. One such process, termed secondary enrichment, is most effective in areas with deep water tables, and many low-grade copper, silver, and uranium deposits have been converted into mineable ore by the downward migration and redeposition of soluble metals. In a desert terrane, placer processes are effective whenever running water flowing over steep slopes erodes outcropping ore bodies and transports and concentrates the heavier ore minerals at lower levels, thus converting low-grade or hard-to-mine bedrock deposits into economically workable concentrations. Other kinds of deposits are better preserved in deserts because the lower rainfall at the surface, and the lower volume of flow and the greater depths to groundwater, result in less destruction of soluble ores; deposits of salines and phosphates are the most notable ores affected by these factors. Still other ore deposits are created as a consequence of the arid climate, mostly because the high evaporation rates operating on standing bodies of water produce brines that can lead directly to concentrations of salts and indirectly to secondary minerals, such as zeolites, that are produced by reaction of silicate minerals with saline waters

New process for weld metal reliability

International Nuclear Information System (INIS)

Hebel, A.G.

1985-01-01

The industry-wide nature of weld cracking alerts one to the possibility that there is a fundamental law being overlooked. And in overlooking this law, industry is unable to counteract it. That law mandates that restraint during welding causes internal stress; internal stress causes weld metal to crack. Component restraint during welding, according to the welding standard, is the major cause of weld metal failures. When the metal working industry accepts this fact and begins to counter the effects of restraint, the number of weld failures experienced fall dramatically. Bonal Technologies, inc., of Detroit, has developed the first consistently effective non-thermal process to relieve stress caused by restraint during welding. Bonal's patented Mets-Lax sub-resonant stress relief acts as a restraint neutralizer when used during welding. Meta-Lax weld conditioning produces a finer more uniform weld grain structure. A finer, more uniform grain structure is a clear metallurgical indication of improved mechanical weld properties. Other benefits like less internal stress, and less warpage are also achieved

Effects of pollution and bioleaching process on the mineral composition and texture of contaminated sediments of the Reconquista River, Argentina.

Science.gov (United States)

Tufo, Ana E; Porzionato, Natalia F; Curutchet, Gustavo

2017-10-31

In this work, we report on the structural and textural changes in fluvial sediments from Reconquista River´s basin, Argentina, due to processes of contamination with organic matter and remediation by bioleaching. The original uncontaminated matrix showed quartz and phyllosilicates as the main primary mineral constituents and phases of interstratified illite-montmorillonite as secondary minerals. It was found that in contaminated sediments, the presence of organic matter in high concentration causes changes in the specific surface area, particle size distribution, size and distribution of micro and meso, and the morphology of the particles with respect to the uncontaminated sediment. After the bioleaching process, there were even greater changes in these parameters at the level of secondary mineral formation and the appearance of nanoparticles, which were confirmed by SEM. Especially, we found the formation of cementing substances such as gypsum, promoting the formation of macroporous aggregates and the weathering of clay components. Our results indicate that the bioleaching not only decreases the content of metals but also favors the formation of a material with improved characteristics for potential future applications.

Mineralization and biodegradability enhancement of Methyl Orange dye by an effective advanced oxidation process

International Nuclear Information System (INIS)

Paul Guin, Jhimli; Bhardwaj, Y.K.; Varshney, Lalit

2017-01-01

An effective process for the oxidation of Methyl Orange dye (MO) was determined by comparing the mineralization efficiency between two advanced oxidation processes (AOPs) viz., ozonolysis and gamma radiolysis in presence and absence of an added inorganic salt potassium persulfate (K_2S_2O_8). The effects of various operating parameters such as ozone flow rate and reaction temperature were optimized to achieve the best possible mineralization extent of MO by ozonolysis. The mineralization efficiency of MO was significantly enhanced during gamma radiolysis in presence of K_2S_2O_8 (γ+K_2S_2O_8) compared to in absence of K_2S_2O_8. The presence of methyl group at the amine of phenyl ring assisted the mineralization of dye during γ+K_2S_2O_8. The oxygen-equivalent chemical-oxidation capacities (OCC) of ozonolysis and γ+K_2S_2O_8 for 75% mineralization of the dye solution were calculated as 7.008 and 0.0336 kg equiv. O_2 m"−"3, respectively which signifies that γ+K_2S_2O_8 can be explored as an effective AOP. The non-biodegradable MO dye solution became biodegradable even after the dose of 0.5 kGy during γ+K_2S_2O_8 compared to 1 kGy in absence of K_2S_2O_8. The study concludes that a lower dose γ+K_2S_2O_8 could be one of the efficient pretreatment steps before undergoing biological degradation of dye solution. - Highlights: • Systematic investigation was performed for the treatment of Methyl Orange dye solution. • AOPs investigated were ozonolysis and gamma radiolysis. • The OCC and % mineralizations of the AOPs were compared. • Gamma radiolysis in presence of K_2S_2O_8 was found as most effective AOP.

Performance simulation of serpentine type metallic and non-metallic solar collector

International Nuclear Information System (INIS)

Al-Sageer, A. A. M.; Alowa, M. I.; Saad, M.

2006-01-01

This paper presents a theoretical investigation of metallic and non-metalic solar water collector models for evaluating its performane parameters. The determined parameters include heat removal factor , overall heat loss coefficients, heat gain, daily and hourly efficiencies. The present study reports that, under forced circulation lest, the non-metallic collector has an inferior performance parameters when compared to that of the metallic one. It was also revealed that the overall heat loss coefficients of both collectors show weak dependence on the flow rate variations. It was also noticed that the heat removal factor forboth models is more sensitive to the flow rate variations. Also noticed that the heat removal factor for both models is more sensitive to the flow rate variations. Also, a comparision of performance parameters of the theoretical and experimental studies showed good agreements for most hours of the day, except the results obtained at the early morning and late after noon hours.(Author)

Decontamination of alpha contaminated metallic waste by cerium IV redox process

International Nuclear Information System (INIS)

Shah, J.G.; Dhami, P.S.; Gandhi, P.M.; Wattal, P.K.

2012-01-01

Decontamination of alpha contaminated metallic waste is an important aspect in the management of waste generated during dismantling and decommissioning of nuclear facilities. Present work on cerium redox process targets decontamination of alpha contaminated metallic waste till it qualifies for the non alpha waste category for disposal in near surface disposal facility. Recovery of the alpha radio nuclides and cerium from aqueous secondary waste streams was also studied deploying solvent extraction process and established. The alpha-lean secondary waste stream has been immobilised in cement based matrix for final disposal. (author)

Recent Progress on Data-Based Optimization for Mineral Processing Plants

Directory of Open Access Journals (Sweden)

Jinliang Ding

2017-04-01

Full Text Available In the globalized market environment, increasingly significant economic and environmental factors within complex industrial plants impose importance on the optimization of global production indices; such optimization includes improvements in production efficiency, product quality, and yield, along with reductions of energy and resource usage. This paper briefly overviews recent progress in data-driven hybrid intelligence optimization methods and technologies in improving the performance of global production indices in mineral processing. First, we provide the problem description. Next, we summarize recent progress in data-based optimization for mineral processing plants. This optimization consists of four layers: optimization of the target values for monthly global production indices, optimization of the target values for daily global production indices, optimization of the target values for operational indices, and automation systems for unit processes. We briefly overview recent progress in each of the different layers. Finally, we point out opportunities for future works in data-based optimization for mineral processing plants.

Biological role in the transformation of platinum-group mineral grains

Science.gov (United States)

Reith, Frank; Zammit, Carla M.; Shar, Sahar S.; Etschmann, Barbara; Bottrill, Ralph; Southam, Gordon; Ta, Christine; Kilburn, Matthew; Oberthür, Thomas; Ball, Andrew S.; Brugger, Joël

2016-04-01

Platinum-group elements are strategically important metals. Finding new deposits is becoming increasingly difficult owing to our limited understanding of the processes that affect their mobility in surface environments. Microorganisms have been shown to promote the mobility of metals around ore deposits. Here we show that microorganisms influence the mobility of platinum-group elements in mineral grains collected from Brazil, Australia and Colombia. Scanning electron microscopy showed biofilms covering the platinum-group mineral grains. The biofilms contained abundant platinum-group element nanoparticles and microcrystalline aggregates, and were dominated by Proteobacteria, many of which were closely related to known metal-resistant species. Some platinum-group mineral grains contained carbon, nitrogen, sulfur, selenium and iodine, suggesting the grains may be biogenic in origin. Molecular analyses show that Brazilian platinum-palladium grains hosted specific bacterial communities, which were different in composition from communities associated with gold grains, or communities in surrounding soils and sediments. Nano-phase metallic platinum accumulated when a metallophillic bacterium was incubated with a percolating platinum-containing medium, suggesting that biofilms can cause the precipitation of mobile platinum complexes. We conclude that biofilms are capable of forming or transforming platinum-group mineral grains, and may play an important role for platinum-group element dispersion and re-concentration in surface environments.

Glycine Polymerization on Oxide Minerals

Science.gov (United States)

Kitadai, Norio; Oonishi, Hiroyuki; Umemoto, Koichiro; Usui, Tomohiro; Fukushi, Keisuke; Nakashima, Satoru

2017-06-01

It has long been suggested that mineral surfaces played an important role in peptide bond formation on the primitive Earth. However, it remains unclear which mineral species was key to the prebiotic processes. This is because great discrepancies exist among the reported catalytic efficiencies of minerals for amino acid polymerizations, owing to mutually different experimental conditions. This study examined polymerization of glycine (Gly) on nine oxide minerals (amorphous silica, quartz, α-alumina and γ-alumina, anatase, rutile, hematite, magnetite, and forsterite) using identical preparation, heating, and analytical procedures. Results showed that a rutile surface is the most effective site for Gly polymerization in terms of both amounts and lengths of Gly polymers synthesized. The catalytic efficiency decreased as rutile > anatase > γ-alumina > forsterite > α- alumina > magnetite > hematite > quartz > amorphous silica. Based on reported molecular-level information for adsorption of Gly on these minerals, polymerization activation was inferred to have arisen from deprotonation of the NH3 + group of adsorbed Gly to the nucleophilic NH2 group, and from withdrawal of electron density from the carboxyl carbon to the surface metal ions. The orientation of adsorbed Gly on minerals is also a factor influencing the Gly reactivity. The examination of Gly-mineral interactions under identical experimental conditions has enabled the direct comparison of various minerals' catalytic efficiencies and has made discussion of polymerization mechanisms and their relative influences possible Further systematic investigations using the approach reported herein (which are expected to be fruitful) combined with future microscopic surface analyses will elucidate the role of minerals in the process of abiotic peptide bond formation.

Glycine Polymerization on Oxide Minerals.

Science.gov (United States)

Kitadai, Norio; Oonishi, Hiroyuki; Umemoto, Koichiro; Usui, Tomohiro; Fukushi, Keisuke; Nakashima, Satoru

2017-06-01

It has long been suggested that mineral surfaces played an important role in peptide bond formation on the primitive Earth. However, it remains unclear which mineral species was key to the prebiotic processes. This is because great discrepancies exist among the reported catalytic efficiencies of minerals for amino acid polymerizations, owing to mutually different experimental conditions. This study examined polymerization of glycine (Gly) on nine oxide minerals (amorphous silica, quartz, α-alumina and γ-alumina, anatase, rutile, hematite, magnetite, and forsterite) using identical preparation, heating, and analytical procedures. Results showed that a rutile surface is the most effective site for Gly polymerization in terms of both amounts and lengths of Gly polymers synthesized. The catalytic efficiency decreased as rutile > anatase > γ-alumina > forsterite > α- alumina > magnetite > hematite > quartz > amorphous silica. Based on reported molecular-level information for adsorption of Gly on these minerals, polymerization activation was inferred to have arisen from deprotonation of the NH 3 + group of adsorbed Gly to the nucleophilic NH 2 group, and from withdrawal of electron density from the carboxyl carbon to the surface metal ions. The orientation of adsorbed Gly on minerals is also a factor influencing the Gly reactivity. The examination of Gly-mineral interactions under identical experimental conditions has enabled the direct comparison of various minerals' catalytic efficiencies and has made discussion of polymerization mechanisms and their relative influences possible Further systematic investigations using the approach reported herein (which are expected to be fruitful) combined with future microscopic surface analyses will elucidate the role of minerals in the process of abiotic peptide bond formation.

Evaluation of mineral content and heavy metals of dromedary camel milk in Iran

Directory of Open Access Journals (Sweden)

Mahdieh MOSTAFIDI

Full Text Available Abstract The aim of this study was to determine the amount of major mineral compounds and heavy metals of camel milk in Iran. For this purpose camel milk samples were collected from seven regions of Iran include Qazvin, Golestan, Semnan, Sistan-Baluchestan, Khuzestan, Bushehr and Tehran. The samples were analyzed using Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES method. The results showed that among the mineral contents, iron and zinc of camel milk were greater than bovine milk. Based on the codex standard 193-2007 standards, the maximum acceptable limit for lead and cadmium is 20 µg/kg and 10 µg/kg, respectively. The results of this study showed that the measured amounts of lead, cadmium and nickel in all samples were less than the acceptable limit for bovine milk. Bovine milk and dairy products are a poor source of iron, while the obtained data revealed that camel milk is a major source of minerals, especially iron. The camel milk’s iron was 10 times more than bovine milk. However, variations in mineral content in camel milk could be due to feed, stage of lactation, milk collection time, drought conditions, environmental conditions and associated analytical methods. Camel milk recommended as a valuable source of food for the human.

What are we missing? Scope 3 greenhouse gas emissions accounting in the metals and minerals industry

Science.gov (United States)

Greene, Suzanne E.

2018-05-01

Metal and mineral companies have significant greenhouse gas emissions in their upstream and downstream value chains due to outsourced extraction, beneficiation and transportation activities, depending on a firm's business model. While many companies move towards more transparent reporting of corporate greenhouse gas emissions, value chain emissions remain difficult to capture, particularly in the global supply chain. Incomplete reports make it difficult for companies to track emissions reductions goals or implement sustainable supply chain improvements, especially for commodity products that form the base of many other sector's value chains. Using voluntarily-reported CDP data, this paper sheds light on hotspots in value chain emissions for individual metal and mineral companies, and for the sector as a whole. The state of value chain emissions reporting for the industry is discussed in general, with a focus on where emissions could potentially be underestimated and how estimates could be improved.

Minerals Yearbook, volume III, Area Reports—International—Africa and the Middle East

Science.gov (United States)

,

2018-01-01

The U.S. Geological Survey (USGS) Minerals Yearbook discusses the performance of the worldwide minerals and materials industries and provides background information to assist in interpreting that performance. Content of the individual Minerals Yearbook volumes follows:Volume I, Metals and Minerals, contains chapters about virtually all metallic and industrial mineral commodities important to the U.S. economy. Chapters on survey methods, summary statistics for domestic nonfuel minerals, and trends in mining and quarrying in the metals and industrial mineral industries in the United States are also included.Volume II, Area Reports: Domestic, contains a chapter on the mineral industry of each of the 50 States and Puerto Rico and the Administered Islands. This volume also has chapters on survey methods and summary statistics of domestic nonfuel minerals.Volume III, Area Reports: International, is published as four separate reports. These regional reports contain the latest available minerals data on more than 180 foreign countries and discuss the importance of minerals to the economies of these nations and the United States. Each report begins with an overview of the region’s mineral industries during the year. It continues with individual country chapters that examine the mining, refining, processing, and use of minerals in each country of the region and how each country’s mineral industry relates to U.S. industry. Most chapters include production tables and industry structure tables, information about Government policies and programs that affect the country’s mineral industry, and an outlook section.The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the Minerals Yearbook are welcomed.

Recovery of drinking water and valuable minerals from acid mine drainage using an integration of magnesite, lime, soda ash, CO(sub)2 and reverse osmosis treatment processes

CSIR Research Space (South Africa)

Masindi, Vhahangwele

2017-08-01

Full Text Available that drinking water, metals, gypsum, hydrated lime/limestone were recovered from the treatment process as valuable resources. This was confirmed by X-ray diffraction (XRD) and X-ray Fluorescence (XRF). Morphological properties of initial and recovered minerals...

Application of liquid metals for the extraction of solid metals

International Nuclear Information System (INIS)

Borgstedt, H.U.

1996-01-01

Liquid metals dissolve several solid metals in considerable amounts at moderate temperatures. The dissolution processes may be based upon simple physical solubility, formation of intermetallic phases. Even chemical reactions are often observed in which non-metallic elements might be involved. Thus, the capacity to dissolve metals and chemical properties of the liquid metals play a role in these processes. Besides the solubility also chemical properties and thermochemical data are of importance. The dissolution of metals in liquid metals can be applied to separate the solutes from other metals or non-metallic phases. Relatively noble metals can be chemically reduced by the liquid phases. Such solution processes can be applied in the extractive metallurgy, for instance to extract metals from metallic waste. The recycling of metals is of high economical and ecological importance. Examples of possible processes are discussed. (author)

Process for continuous distillation of bituminous minerals, etc

Energy Technology Data Exchange (ETDEWEB)

Marie, J J

1923-01-26

An apparatus is described for operating the process, in which the petroleum-bearing asphaltic or bituminous minerals are charged to the upper part of a vertical furnace with a lining of refractory material and varying sections; air is necessary for combustion and inert gas is necessary to regulate this combustion and to remove the hydrocarbons being blown into the lower part of the furnace; the hydrocarbons in vapor state or gases being removed are received in the condensers where they are deposited in the liquid state; the liquid from the condensers is next centrifuged to give oils essentially like natural petroleum, leaving as residue solid hydrocarbons and entrained mineral; the minerals treated are removed by gravity at the bottom of the furnace.

Release of microspherolites and metals extraction from energetical fly ashes by Bacillus isolates

Directory of Open Access Journals (Sweden)

Štyriaková Iveta

2000-09-01

Full Text Available The amorphous secondary silicate mineral components formed in the process of coal combustion dominate in the composition of energy fly-ash. Depending on the composition of coal concentrate, this secondary raw material source also contains the industrially interesting components, e.g. titanium (eventually iron and aluminium and can be considered as a non-metallic material suitable for the construction industry.The main secondary mineral components of the energy fly-ash formed during the coal combustion were studied using SEM (scanning electronic microscope. They can be divided into four groups:1. Amorphous spherical alumocilicate particles in allotriomorphic aluminosilicate grains – they represent a main mineral component of fly-ash, which is formed from the accompanying rocks of coal containing silicate minerals,2. Quartz – which formed a substantial component of accompanying rocks of coal or accompanying accessory mineral of coal together with kaolinite and mica, was transformed into tridymite at the temperature exceeding 870°C and into cristobalite at the temperature exceeding 1470°C. The spherical particles are products of reaction between cristobalite and aluminosilicate, which is a frequent phenomenon occurring during the formation of volcanic rocks. These particles form together a main amorphous phase of fly-ash.3. Mullite – represents a secondary component of fly-ash, which is formed from accompanying clay minerals of coal (kaolinite, mica together with cristobalite under the effect of temperature exceeding 1150°C,4. Non-combusted residue – consists of organic substance, represents a non-combusted ratio of coal as a secondary component of fly-ash.Heterotrophic bacteria of Bacillus genus are capable to remove 66 % of titanium and 33 % of iron from non-deposited fly-ash from Opatovice after 35 days of leaching of samples. The content of solid phase in fly-ash influences the extraction of elements, mainly iron and titatnium, because

Competitive platinum-group-metal (PGM) supply from the Eastern Limb, Bushveld Complex: Geological, mining and mineral economic aspects

CSIR Research Space (South Africa)

McGill, JE

2011-08-01

Full Text Available -GROUP-METAL (PGM) SUPPLY FROM THE EASTERN LIMB, BUSHVELD COMPLEX: GEOLOGICAL, MINING, AND MINERAL ECONOMIC ASPECTS Dr. Jeannette E. McGill & Prof. Murray W. Hitzman ACKNOWLEDGEMENTS ? COUNCIL FOR SCIENTIFIC AND INDUSTRIAL RESEARCH (CSIR) ? Centre for Mining... Innovation ? Office of Graduate Studies, Fogarty Endowment ? Mr. VISHNU PILLAY (EXECUTIVE HEAD: JV?S ? Anglo Platinum) ? ACADEMIC ADVISORS Prof. Murray Hitzman (Economic Geology); Dr. Hugh Miller (Mining Engineering); Prof. Rodderick Eggert (Mineral...

Metal ions released from fixed orthodontic appliance affect hair mineral content.

Science.gov (United States)

Mikulewicz, Marcin; Wołowiec, Paulina; Loster, Bartłomiej; Chojnacka, Katarzyna

2015-02-01

The objective was to evaluate metal ion accumulation in hair of patients undergoing orthodontic treatment with fixed appliances in time. The patients (N = 47) participated in a questionnaire survey. Hair sampling was performed at the beginning and in the 4th, 8th, and 12th month of the treatment. The content of metals (Cr, Ni, Fe) in hair was analyzed by ICP-OES equipped with USN nebulizer. The peak release of Cr and Fe occurred after 4 months of the treatment, and the peak release of Ni gradually increased throughout the whole year of the therapy. During 1 year treatment, an average accumulation of metals in hair tissue was 7.42 ± 14.19 μg of Ni, 8.94 ± 13.1 μg of Cr, and 131 ± 279 μg of Fe. The mean content of Cr was higher than the 90th percentile value for this element. The upper limit of literature reference ranges for Cr, Ni, and Fe in hair was not exceeded. The value of exposure (kinetics and dose) of orthodontic patients to metal ions released from orthodontic appliances can be assessed by hair mineral analysis. The content of Cr was statistically significantly higher during the treatment than before the beginning of therapy.

Implementation of a Non-Metallic Barrier in an Electric Motor

Science.gov (United States)

M?Sadoques, George; Carra, Michael; Beringer, Woody

2012-01-01

Electric motors that run in pure oxygen must be sealed, or "canned," for safety reasons to prevent the oxygen from entering into the electrical portion of the motor. The current canning process involves designing a metallic barrier around the rotor to provide the separation. This metallic barrier reduces the motor efficiency as speed is increased. In higher-speed electric motors, efficiency is greatly improved if a very thin, nonmetallic barrier can be utilized. The barrier thickness needs to be approximately 0.025-in. (.0.6-mm) thick and can be made of a brittle material such as glass. The motors, however, designed for space applications are typically subject to high-vibration environments. A fragile, non-metallic barrier can be utilized in a motor assembly if held in place by a set of standard rubber O-ring seals. The O-rings provide the necessary sealing to keep oxygen away from the electrical portion of the motor and also isolate the fragile barrier from the harsh motor vibration environment. The compliance of the rubber O-rings gently constrains the fragile barrier and isolates it from the harsh external motor environment. The use of a non-metallic barrier greatly improves motor performance, especially at higher speeds, while isolating the electronics from the working fluid with an inert liner.

Leading research on next generation metal production technology; Jisedai kinzoku shigen seisan gijutsu no sendo kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

The energy saving environment-friendly technology for low- grade difficult-to-process ores was researched focusing attention on the hydro-metallurgical process of non-ferrous metals. This research aims at development of both effective leaching system of metals, and separation/crystallization system recognizing the property difference between metal ions in solution. The leaching system allows the inexpensive molecular level control of electron transfer, mass transfer of metal ions and stabilization of leached metal ions in a solid/liquid interface. The system thus allows selective leaching of metals from various resources such as difficult- to-leach sulfide minerals to prepare concentrated solutions. The separation system can obtain high-purity solutions including each metal ion by advanced separation/concentration technology from the solutions. The crystallization technology (including electrolysis) is developed for preparing target metal materials by molecular level control of nucleation, particle growth, thin film formation and bulky metal formation processes. Overall energy consumption is reduced to 1/3 of that of the pyro-metallurgical method, aiming at zero emission. 15 refs., 14 figs., 11 tabs.

Selenide Mineralization in the Příbram Uranium and Base-Metal District (Czech Republic

Directory of Open Access Journals (Sweden)

Pavel Škácha

2017-06-01

Full Text Available Selenium mineralization in the Příbram uranium and base-metal district (Central Bohemia, Czech Republic bound to uraninite occurrences in calcite hydrothermal veins is extremely diverse. The selenides antimonselite, athabascaite, bellidoite, berzelianite, brodtkorbite, bukovite, bytízite, cadmoselite, chaméanite, clausthalite, crookesite, dzharkenite, eskebornite, eucairite, ferroselite, giraudite, hakite, klockmannite, naumannite, permingeatite, příbramite, sabatierite, tiemannite, and umangite were found here, including two new mineral phases: Hg-Cu-Sb and Cu-As selenides. Those selenides—and in some cases their sulphidic equivalents—are characterized using wavelength-dispersive spectroscopy, reflected light, powder X-ray diffraction, single crystal X-ray diffraction, Raman spectroscopy, and electron backscatter diffraction. The selenide mineralization in the Příbram uranium district is bound to the border of the carbonate-uraninite and subsequent carbonate-sulphidic stages. Selenides crystallized there at temperatures near 100 °C in the neutral-to-weakly-alkaline environment from solutions with high oxygen fugacity and a high Se2/S2 fugacity ratio.

Rare earth element lithogeochemistry of granitoid mineral deposits

Energy Technology Data Exchange (ETDEWEB)

Taylor, R.P.; Fryer, B.J. (Memorial Univ. of Newfoundland, St. John' s (Canada). Dept. of Earth Sciences)

1983-12-01

As a monitor of the processes involved in the formation of granitoid mineral deposits the coherent group behaviour of the rare earth elements (REE) actively reflects changing fluid characteristics. For example, in the porphyry environment, magmatic-hydrothermal fluids produce potassic alteration with strong enrichment in the light rare earth elements, reflecting their high pH, low fluid/rock ratios, and the dominant role of Cl/sup -/ complexing in metal (i.e. Cu, Au) transport. With increasing fluid/rock ratios and decreasing pH accompanying the progressive involvement of meteoric fluids (and the production of propylitic, argillic, and phyllic alteration) anionic species such as F/sup -/ and CO/sub 3//sup 2 -/ become important in metal (e.g. Mo, W) transport through complexing, and their activity in the hydrothermal fluids is illustrated by mobilization of the heavy rare earth elements. The relative involvement of Cl/sup -/ versus F/sup -/ versus CO/sub 3//sup 2 -/ in metal transport in other granite-related systems can also be monitored through REE behaviour. Hence granitoid tin-tungsten mineralization and associated greisenization typically exhibit heavy rare earth enrichment and evidence the importance of F/sup -/ and CO/sub 3//sup 2 -/ in metal transport. Similarly, heavy rare earth element enrichment in hydrothermal uranium deposits can be related to the transport of uranium as carbonate complexes. REE are widely accepted as powerful tools in the study of rock petrogenesis, but their use has been neglected in the investigation of mineral deposits. The recognition of the systematic variation of REE distributions in granitoid mineral deposits suggests that the application of REE geochemistry, particularly when integrated with fluid inclusion and isotope studies, can provide l) an effective method for identifying the physiochemical controls of metal transport and 2) a useful criterion of elucidating metal distribution.

Rare earth element lithogeochemistry of granitoid mineral deposits

International Nuclear Information System (INIS)

Taylor, R.P.; Fryer, B.J.

1983-01-01

As a monitor of the processes involved in the formation of granitoid mineral deposits the coherent group behaviour of the rare earth elements (REE) actively reflects changing fluid characteristics. For example, in the porphyry environment, magmatic-hydrothermal fluids produce potassic alteration with strong enrichment in the light rare earth elements, reflecting their high pH, low fluid/rock ratios, and the dominant role of Cl - complexing in metal (i.e. Cu, Au) transport. With increasing fluid/rock ratios and decreasing pH accompanying the progressive involvement of meteoric fluids (and the production of propylitic, argillic, and phyllic alteration) anionic species such as F - and CO 3 2- become important in metal (e.g. Mo, W) transport through complexing, and their activity in the hydrothermal fluids is illustrated by mobilization of the heavy rare earth elements. The relative involvement of Cl - versus F - versus CO 3 2- in metal transport in other granite-related systems can also be monitored through REE behaviour. Hence granitoid tin-tungsten mineralization and associated greisenization typically exhibit heavy rare earth enrichment and evidence the importance of F - and CO 3 2- in metal transport. Similarly, heavy rare earth element enrichment in hydrothermal uranium deposits can be related to the transport of uranium as carbonate complexes. REE are widely accepted as powerful tools in the study of rock petrogenesis, but their use has been neglected in the investigation of mineral deposits. The recognition of the systematic variation of REE distributions in granitoid mineral deposits suggests that the application of REE geochemistry, particularly when integrated with fluid inclusion and isotope studies, can provide l) an effective method for identifying the physiochemical controls of metal transport and 2) a useful criterion of elucidating metal distribution

Infiltration processing of metal matrix composites using coated ceramic particulates

Science.gov (United States)

Leon-Patino, Carlos Alberto

2001-07-01

A new process was developed to fabricate particulate metal matrix composites (MMCs). The process involves three steps: (1) modifying the particulate surface by metal coating, (2) forming a particulate porous compact; and (3) introducing metal into the channel network by vacuum infiltration. MMCs with different reinforcements, volume fractions, and sizes can be produced by this technique. Powders of alumina and silicon carbide were successfully coated with nickel and copper in preparation for infiltration with molten aluminum. Electroless Ni and Cu deposition was used since it enhances the wettability of the reinforcements for composite fabrication. While Cu deposits were polycrystalline, traces of phosphorous co-deposited from the electroless bath gave an amorphous Ni-P coating. The effect of metal coating on wetting behavior was evaluated at 800°C on plain and metal-coated ceramic plates using a sessile drop technique. The metallic films eliminated the non-wetting behavior of the uncoated ceramics, leading to equilibrium contact angles in the order of 12° and below 58° for Ni and Cu coated ceramics, respectively. The spreading data indicated that local diffusion at the triple junction was the governing mechanism of the wetting process. Precipitation of intermetallic phases in the drop/ceramic interface delayed the formation of Al4C3. Infiltration with molten Al showed that the coated-particulates are suitable as reinforcing materials for fabricating MMCs, giving porosity-free components with a homogeneously distributed reinforcing phase. The coating promoted easy metal flow through the preform, compared to the non-infiltration behavior of the uncoated counterparts. Liquid state diffusion kinetics due to temperature dependent viscosity forces controlled the infiltration process. Microstructural analysis indicated the formation of intermetallic phases such as CuAl 2, in the case of Cu coating, and Ni2Al3 and NiAl 3 when Ni-coated powders were infiltrated. The

Heavy metal sequestration by humic substances during phyto-treatment of sewage sludges

International Nuclear Information System (INIS)

Peruzzi, E.; Doni, S.; Macci, C.; Ceccanti, B.; Masciandaro, G.

2009-01-01

The presence of heavy metals in sludges stabilized in a reed bed system, may affect their use for agricultural purposes; however, the environmental impact of sludges depends on the availability and phyto toxicity of their heavy metal. The aim of this paper was to determine the effectiveness of a reed bed (Phragmites Australia) sludge treatment system in two urban wastewater treatment plants in Italy after two-year period of operation: by estimating the process of sludge stabilization, following conventional and non conventional parameters related with the evolution of organic matter quality Water soluble Carbon, Dehydrogenase activity, Fulvic Acids, Humic Acids, Pyrolytic indices or organic matter Mineralization and Humification); by following the heavy metal speciation bioavailability in sludges. (Author)

Clay minerals and metal oxides strongly influence the structure of alkane-degrading microbial communities during soil maturation.

Science.gov (United States)

Steinbach, Annelie; Schulz, Stefanie; Giebler, Julia; Schulz, Stephan; Pronk, Geertje J; Kögel-Knabner, Ingrid; Harms, Hauke; Wick, Lukas Y; Schloter, Michael

2015-07-01

Clay minerals, charcoal and metal oxides are essential parts of the soil matrix and strongly influence the formation of biogeochemical interfaces in soil. We investigated the role of these parental materials for the development of functional microbial guilds using the example of alkane-degrading bacteria harbouring the alkane monooxygenase gene (alkB) in artificial mixtures composed of different minerals and charcoal, sterile manure and a microbial inoculum extracted from an agricultural soil. We followed changes in abundance and community structure of alkane-degrading microbial communities after 3 and 12 months of soil maturation and in response to a subsequent 2-week plant litter addition. During maturation we observed an overall increasing divergence in community composition. The impact of metal oxides on alkane-degrading community structure increased during soil maturation, whereas the charcoal impact decreased from 3 to 12 months. Among the clay minerals illite influenced the community structure of alkB-harbouring bacteria significantly, but not montmorillonite. The litter application induced strong community shifts in soils, maturated for 12 months, towards functional guilds typical for younger maturation stages pointing to a resilience of the alkane-degradation function potentially fostered by an extant 'seed bank'.

On the theory system of hydrothermal uranium metallization in China

International Nuclear Information System (INIS)

Du Letian

2011-01-01

Based on summarizing the mass of research outcome of the predecessors, the author attempts to make a brief generalization on the theory system of hydrothermal uranium mineralization in China. The system of uranium metallization is founded in the basic way of uranium source-migration-transportation-richment-reservation. The system mainly consists of the following frames: (1) mineralization type of silification zone; (2) age gap of mineralization to host rock; (3) alkli metasomatism; (4) metallogenic layer of crust; (5)integratation of 4 types mineralization (granite, volcanics, carbonaceous-siliceous-argilaceous rock and sandstone) in tectonic-hydrothermal process; (6) pre-enrichment process of metallization; (7) decouplement of granite magma evolution; (8) types of rich ore by high tempreture sericitization; (9)basalt event;(10) rock and ore formation by HARCON. (authors)

Tracer investigations of macroprocesses in mineral processing. 1

International Nuclear Information System (INIS)

Koch, P.

1981-01-01

Results obtained from tracer studies in mineral processing have been evaluated with regard to the effects of hydrodynamic and design parameters of the single cell on flotation kinetics, to the residence time in single and in series-connected cells, and to the possibility of designing process control models. An algorithm is given for technological interpretation of results obtained from residence time and process kinetics studies

Cobalt deposition in mineralized bone tissue after metal-on-metal hip resurfacing: Quantitative μ-X-ray-fluorescence analysis of implant material incorporation in periprosthetic tissue.

Science.gov (United States)

Hahn, Michael; Busse, Björn; Procop, Mathias; Zustin, Jozef; Amling, Michael; Katzer, Alexander

2017-10-01

Most resurfacing systems are manufactured from cobalt-chromium alloys with metal-on-metal (MoM) bearing couples. Because the quantity of particulate metal and corrosion products which can be released into the periprosthetic milieu is greater in MoM bearings than in metal-on-polyethylene (MoP) bearings, it is hypothesized that the quantity and distribution of debris released by the MoM components induce a compositional change in the periprosthetic bone. To determine the validity of this claim, nondestructive µ-X-ray fluorescence analysis was carried out on undecalcified histological samples from 13 femoral heads which had undergone surface replacement. These samples were extracted from the patients after gradient time points due to required revision surgery. Samples from nonintervened femoral heads as well as from a MoP resurfaced implant served as controls. Light microscopy and µ-X-ray fluorescence analyses revealed that cobalt debris was found not only in the soft tissue around the prosthesis and the bone marrow, but also in the mineralized bone tissue. Mineralized bone exposed to surface replacements showed significant increases in cobalt concentrations in comparison with control specimens without an implant. A maximum cobalt concentration in mineralized hard tissue of up to 380 ppm was detected as early as 2 years after implantation. Values of this magnitude are not found in implants with a MoP surface bearing until a lifetime of more than 20 years. This study demonstrates that hip resurfacing implants with MoM bearings present a potential long-term health risk due to rapid cobalt ion accumulation in periprosthetic hard tissue. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1855-1862, 2017. © 2016 Wiley Periodicals, Inc.

Selection of a mineral binder for the stabilization - solidification of waste containing aluminum metal

International Nuclear Information System (INIS)

Lahalle, H.; Cau Dit Counes, C.; Lambertin, D.; Antonucci, P.; Delpech, S.

2015-01-01

The dismantling of nuclear facilities produces radioactive waste materials, some of which may contain aluminum metal. In a strongly alkaline medium, such as that encountered in conventional cementitious materials based on Portland cement, aluminum metal becomes corroded, with a continued production of dihydrogen. In order to develop a mineral matrix having enhanced compatibility with aluminum, a literature review was first undertaken to identify binders capable of reducing the pore solution pH compared with Portland cement. An experimental study was then carried out to measure the hydrogen production resulting from corrosion of aluminum metal rods encapsulated in the different selected cement pastes. The best results were achieved with magnesium phosphate cement, which released very little hydrogen over the duration of the study. This production could be reduced further by adding a corrosion inhibitor (lithium nitrate) to the mixing solution

Process for treating waters and sludges and device for developing this process

International Nuclear Information System (INIS)

Levaillant, Claude.

1977-01-01

The description is given of a process for treating waters and sludge by means of a ionizing radiation beam, featuring the following stages: settlement of primary waters and sludge, centrifugation of the settled waters and sludge in order to separate the waste waters, the sludge formed of organic compounds charged with heavy metals and the sludge formed of mineral compounds, irradiation, by ionizing radiation beam, of the sludge formed of organic compounds, containing heavy metals, and which are transformed into less toxic and denser recoverable mineral compounds, centrifugation of the irradiated sludge making it possible to obtain clarified waters treated by irradiation, sludge composed of organic compounds freed of their heavy metals and sludge formed of mineral compounds containing heavy metals and which will be easily separated owing to their high density [fr

Molecular Studies of Complex Soil Organic Matter Interactions with Metal Ions and Mineral Surfaces using Classical Molecular Dynamics and Quantum Chemistry Methods

Science.gov (United States)

Andersen, A.; Govind, N.; Laskin, A.

2017-12-01

Mineral surfaces have been implicated as potential protectors of soil organic matter (SOM) against decomposition and ultimate mineralization to small molecules which can provide nutrients for plants and soil microbes and can also contribute to the Earth's elemental cycles. SOM is a complex mixture of organic molecules of biological origin at varying degrees of decomposition and can, itself, self-assemble in such a way as to expose some biomolecule types to biotic and abiotic attack while protecting other biomolecule types. The organization of SOM and SOM with mineral surfaces and solvated metal ions is driven by an interplay of van der Waals and electrostatic interactions leading to partitioning of hydrophilic (e.g. sugars) and hydrophobic (e.g., lipids) SOM components that can be bridged with amphiphilic molecules (e.g., proteins). Classical molecular dynamics simulations can shed light on assemblies of organic molecules alone or complexation with mineral surfaces. The role of chemical reactions is also an important consideration in potential chemical changes of the organic species such as oxidation/reduction, degradation, chemisorption to mineral surfaces, and complexation with solvated metal ions to form organometallic systems. For the study of chemical reactivity, quantum chemistry methods can be employed and combined with structural insight provided by classical MD simulations. Moreover, quantum chemistry can also simulate spectroscopic signatures based on chemical structure and is a valuable tool in interpreting spectra from, notably, x-ray absorption spectroscopy (XAS). In this presentation, we will discuss our classical MD and quantum chemistry findings on a model SOM system interacting with mineral surfaces and solvated metal ions.

Research on Lessening of Bonding Effects Between the Metallic and Non-Metallic Surfaces Through the Graphite Films Deposited with Pulsed Electrical Discharges Process

Science.gov (United States)

Marin, L.; Topala, P.

2017-06-01

The paper presents the results of experimental research on the physics of natural graphite film formation, the establishment of chemical composition and functional properties of the graphite films, formed on metal surfaces, as a result of the action of plasma in the air environment, at a normal pressure, under the electrical discharge in impulse conditions (EDI). The researchings were performed in the frame of doctoral thesis “Research on lessening of the bonding effects between the metallic and nonmetallic surfaces through the graphite films” and aimed to identify the phenomena that occur at the interface metal/ film of graphite, and to identify also the technological applications that it may have the surface treatment for submitting the films of graphite on metallic surfaces achieved through an innovative process of electrical pulsed discharges. After the research works from the PhD theme above mentioned, a number of interesting properties of graphite pellicle have been identified ie reducing of metal surface polarity. This led to drastic decreases for the values of adhesion when bonding of metal surfaces was performed using a structural polyurethane adhesive designed by ICECHIM. Following the thermo-gravimetric analysis, performed of the graphite film obtained by process of electrical pulsed discharges, have been also discovered other interesting properties for this, ie reversible mass additions at specific values of the working temperature Chemical and scanning electron microscopy analysis have revealed that on the metallic surface subjected to electrical pulsed discharges process, outside the graphite film, it is also obtained a series of spatial formation composed of carbon atoms fullerenes type which are responsible for the phenomenon of addition of mass.

Petrochemical Characteristics and Age of Rare Metal (Ta-Nb Mineralization in Precambrian Pegmatites, Komu, Nigeria

Directory of Open Access Journals (Sweden)

A. OLUGBENGA

2010-06-01

Full Text Available The Precambrian pegmatites of Komu area intrude semi discordantly older rock types, such as biotite gneiss, amphibolites and pelitic schists. The pegmatites occur as near flat lying bodies. This study aims at elucidating the geological setting, petrography, geochemical features and age of mineralization of these pegmatite bodies, with a view to classifying them and knowing their economic potential. The petrographic analysis shows that the pegmatite samples contain mainly quartz (35%, plagioclase (15%, microcline (10% and muscovite (12% with accessories like tourmaline, tantalum, niobium and illmeno-rutiles. Geochemical analysis of the muscovites extracted from pegmatites show that these rocks are enriched in silica (>60% and Al2O3 (>12% and depleted in Fe2O3, MgO and TiO2. Trace element analysis shows that the pegmatites contain rare metals with moderately high Ta, Nb, Sn, Rb, Li and Cs values and depleted in Ti, Ba and Zr. Elemental ratios indicate low ratios of K/Cs, Th/U and K/Rb. Variation plots of Ta/(Ta+Nb versus Mn/ (Mn+Fe show that the pegmatites plot in the complex (beryl subtype field. The Na/K versus Sn, Nb, Rb variation plots show that the pegmatites of Komu area are mineralized and compare favourably with those of other mineralized pegma-tite areas like Egbe and Ijero in southwestern Nigeria. The variation plots of Ta versus K/Cs, and Ta/W versus Cs, also confirm rare metal mineralization of Komu pegmatites, which plot over the mineralized line of Beus and Gordiyenko. The K/Rb versus Rb, Cs and Sn plots indicate low K/Rb ratios indicating moderate differentiation. The Rare Earth Elements (REE show high heavy REE values and lower light REE values with prominent positive Ce anomaly and negative Eu anomaly from normalized chondrite plots. K/Ar dating of the age of mineralization of muscovites extracted from the pegmatite yielded late Pan-African ages between 502.8±13Ma and 514.5±13.2Ma. This period represents the cooling ages of the

Pyrometallurgical processing for raw materials of heavy non-ferrous metals and furnace for carrying it out. Pyrometallurgisches Verarbeitungsverfahren fuer Rohstoffe schwerer Buntmetalle und Ofen zu dessen Realisierung

Energy Technology Data Exchange (ETDEWEB)

Vanjukov, A V; Metschev, V V; Bystrov, V P; Eschov, E I; Vasiliev, M G; Zaitsev, V Y; Romenets, V A; Ivanov, V V; Golik, S Y; Grin-Gnatovsky, E S

1980-06-04

Pyrometallurgical processing is described, by which non-ferrous metals are obtained from a melt. The pneumatic mixing of melt material and the oxidation of sulphide and oxide starting material is done by blowing a flow of gas with more than 35% oxygen content into it. The layers of slag, ore and raw metal formed in the furnace can be separated. The construction of the furnace is described in detail. 4 examples complete the description.

MINERAL PROCESSING BY SHORT CIRCUITS IN PROTOPLANETARY DISKS

Energy Technology Data Exchange (ETDEWEB)

McNally, Colin P. [Niels Bohr International Academy, Niels Bohr Institute, DK-2100 Copenhagen (Denmark); Hubbard, Alexander; Mac Low, Mordecai-Mark [Department of Astrophysics, American Museum of Natural History, New York, NY 10024-5192 (United States); Ebel, Denton S. [Department of Earth and Planetary Sciences, American Museum of Natural History, New York, NY 10024-5192 (United States); D' Alessio, Paola, E-mail: cmcnally@nbi.dk, E-mail: ahubbard@amnh.org, E-mail: mordecai@amnh.org, E-mail: debel@amnh.org, E-mail: p.dalessio@crya.unam.mx [Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, 58089 Morelia, MICH (Mexico)

2013-04-10

Meteoritic chondrules were formed in the early solar system by brief heating of silicate dust to melting temperatures. Some highly refractory grains (Type B calcium-aluminum-rich inclusions, CAIs) also show signs of transient heating. A similar process may occur in other protoplanetary disks, as evidenced by observations of spectra characteristic of crystalline silicates. One possible environment for this process is the turbulent magnetohydrodynamic flow thought to drive accretion in these disks. Such flows generally form thin current sheets, which are sites of magnetic reconnection, and dissipate the magnetic fields amplified by a disk dynamo. We suggest that it is possible to heat precursor grains for chondrules and other high-temperature minerals in current sheets that have been concentrated by our recently described short-circuit instability. We extend our work on this process by including the effects of radiative cooling, taking into account the temperature dependence of the opacity; and by examining current sheet geometry in three-dimensional, global models of magnetorotational instability. We find that temperatures above 1600 K can be reached for favorable parameters that match the ideal global models. This mechanism could provide an efficient means of tapping the gravitational potential energy of the protoplanetary disk to heat grains strongly enough to form high-temperature minerals. The volume-filling nature of turbulent magnetic reconnection is compatible with constraints from chondrule-matrix complementarity, chondrule-chondrule complementarity, the occurrence of igneous rims, and compound chondrules. The same short-circuit mechanism may perform other high-temperature mineral processing in protoplanetary disks such as the production of crystalline silicates and CAIs.

Ventilatory Function in Relation to Mining Experience and Smoking in a Random Sample of Miners and Non-miners in a Witwatersrand Town1

Science.gov (United States)

Sluis-Cremer, G. K.; Walters, L. G.; Sichel, H. S.

1967-01-01

The ventilatory capacity of a random sample of men over the age of 35 years in the town of Carletonville was estimated by the forced expiratory volume and the peak expiratory flow rate. Five hundred and sixty-two persons were working or had worked in gold-mines and 265 had never worked in gold-mines. No difference in ventilatory function was found between the miners and non-miners other than that due to the excess of chronic bronchitis in miners. PMID:6017134

Comparative study of resist stabilization techniques for metal etch processing

Science.gov (United States)

Becker, Gerry; Ross, Matthew F.; Wong, Selmer S.; Minter, Jason P.; Marlowe, Trey; Livesay, William R.

1999-06-01

This study investigates resist stabilization techniques as they are applied to a metal etch application. The techniques that are compared are conventional deep-UV/thermal stabilization, or UV bake, and electron beam stabilization. The electron beam tool use din this study, an ElectronCure system from AlliedSignal Inc., ELectron Vision Group, utilizes a flood electron source and a non-thermal process. These stabilization techniques are compared with respect to a metal etch process. In this study, two types of resist are considered for stabilization and etch: a g/i-line resist, Shipley SPR-3012, and an advanced i-line, Shipley SPR 955- Cm. For each of these resist the effects of stabilization on resist features are evaluated by post-stabilization SEM analysis. Etch selectivity in all cases is evaluated by using a timed metal etch, and measuring resists remaining relative to total metal thickness etched. Etch selectivity is presented as a function of stabilization condition. Analyses of the effects of the type of stabilization on this method of selectivity measurement are also presented. SEM analysis was also performed on the features after a compete etch process, and is detailed as a function of stabilization condition. Post-etch cleaning is also an important factor impacted by pre-etch resist stabilization. Results of post- etch cleaning are presented for both stabilization methods. SEM inspection is also detailed for the metal features after resist removal processing.

Quantitative Measures of Mineral Supply Risk

Science.gov (United States)

Long, K. R.

2009-12-01

Almost all metals and many non-metallic minerals are traded internationally. An advantage of global mineral markets is that minerals can be obtained from the globally lowest-cost source. For example, one rare-earth element (REE) mine in China, Bayan Obo, is able to supply most of world demand for rare earth elements at a cost significantly less than its main competitors. Concentration of global supplies at a single mine raises significant political risks, illustrated by China’s recent decision to prohibit the export of some REEs and severely limit the export of others. The expected loss of REE supplies will have a significant impact on the cost and production of important national defense technologies and on alternative energy programs. Hybrid vehicles and wind-turbine generators, for example, require REEs for magnets and batteries. Compact fluorescent light bulbs use REE-based phosphors. These recent events raise the general issue of how to measure the degree of supply risk for internationally sourced minerals. Two factors, concentration of supply and political risk, must first be addressed. Concentration of supply can be measured with standard economic tools for measuring industry concentration, using countries rather than firms as the unit of analysis. There are many measures of political risk available. That of the OECD is a measure of a country’s commitment to rule-of-law and enforcement of contracts, as well as political stability. Combining these measures provides a comparative view of mineral supply risk across commodities and identifies several minerals other than REEs that could suddenly become less available. Combined with an assessment of the impact of a reduction in supply, decision makers can use these measures to prioritize risk reduction efforts.

NON-LINEAR FINITE ELEMENT MODELING OF DEEP DRAWING PROCESS

Directory of Open Access Journals (Sweden)

Hasan YILDIZ

2004-03-01

Full Text Available Deep drawing process is one of the main procedures used in different branches of industry. Finding numerical solutions for determination of the mechanical behaviour of this process will save time and money. In die surfaces, which have complex geometries, it is hard to determine the effects of parameters of sheet metal forming. Some of these parameters are wrinkling, tearing, and determination of the flow of the thin sheet metal in the die and thickness change. However, the most difficult one is determination of material properties during plastic deformation. In this study, the effects of all these parameters are analyzed before producing the dies. The explicit non-linear finite element method is chosen to be used in the analysis. The numerical results obtained for non-linear material and contact models are also compared with the experiments. A good agreement between the numerical and the experimental results is obtained. The results obtained for the models are given in detail.

Non-hydrolytic metal oxide films for perovskite halide overcoating and stabilization

Science.gov (United States)

Martinson, Alex B.; Kim, In Soo

2017-09-26

A method of protecting a perovskite halide film from moisture and temperature includes positioning the perovskite halide film in a chamber. The chamber is maintained at a temperature of less than 200 degrees Celsius. An organo-metal compound is inserted into the chamber. A non-hydrolytic oxygen source is subsequently inserted into the chamber. The inserting of the organo-metal compound and subsequent inserting of the non-hydrolytic oxygen source into the chamber is repeated for a predetermined number of cycles. The non-hydrolytic oxygen source and the organo-metal compound interact in the chamber to deposit a non-hydrolytic metal oxide film on perovskite halide film. The non-hydrolytic metal oxide film protects the perovskite halide film from relative humidity of greater than 35% and a temperature of greater than 150 degrees Celsius, respectively.

Kinetics and mechanisms of metal retention/release in geochemical processes in soil. 1998 annual progress report

International Nuclear Information System (INIS)

Taylor, R.W.

1998-01-01

'The long-term fate of toxic metals in soils cannot be precisely predicted, and often remediation recommendations and techniques may be ineffective or unnecessary. This work will generate basic knowledge on the kinetics and mechanism(s) of heavy metal retention/release by soil mineral colloids. The information should assist in improving remediation strategies for toxic heavy metal contaminated soils. The objectives are: (1) To determine the effects of residence time on the mechanisms of Cr(VI), Cu(II), Co(II), Cd(II), Pb(II), and Ni(II) sorption/release on Fe and Al oxide and clay mineral surfaces using kinetic studies coupled to extended x-ray absorption fine structure (EXAFS) spectroscopy and fourier transform infrared (FTIR) spectroscopy. (2) To study the effect of temperature, pH, and phosphate on metal sorption by oxides, and derive thermodynamic parameters to describe the sorption process. As of June, 16, 1997 several clay minerals were tested for their efficiency of removing Cr from aqueous systems. The materials tested--smectite, vermiculites, illites, and kaolinite--represent the natural clay minerals that are abundant in soils and sediments. The clays were used in either their original or reduced (reduced with sodium dithionite) forms. The experimental result indicate that the reduced clays acted as an efficient remover of Cr(VI) from an aqueous system. The XANES spectra of Cr-treated clays provided evidence that the clays reduced Cr(VI) to Cr(III) and immobilized Cr in the clays at the same time. Sodium dithionite applied directly into aqueous systems reduced Cr(VI) to Cr(III), but could not immobilize Cr even in the presence of the clays. The Cr(VI) removal capacity varied with the clay mineral type and the structural Fe content. For the clays used in this study, the removal capacity follows the orders of smectites > vermiculites and illites > kaolinite. Within the same type of clay minerals, reduction of Cr(VI) is highly related to the ferrous iron

Environmental impact assessment of european non-ferro mining industries through life-cycle assessment

Science.gov (United States)

Hisan Farjana, Shahjadi; Huda, Nazmul; Parvez Mahmud, M. A.

2018-05-01

European mining industries are the vast industrial sector which contributes largely on their economy which constitutes of ferro and non-ferro metals and minerals industries. The non-ferro metals extraction and processing industries require focus of attention due to sustainability concerns as their manufacturing processes are highly energy intensive and impacts globally on environment. This paper analyses major environmental effects caused by European metal industries based on the life-cycle impact analysis technologies. This research work is the first work in considering the comparative environmental impact analysis of European non-ferro metal industries which will reveal their technological similarities and dissimilarities to assess their environmental loads. The life-cycle inventory datasets are collected from the EcoInvent database while the analysis is done using the CML baseline and ReCipe endpoint method using SimaPro software version 8.4. The CML and ReCipe method are chosen because they are specialized impact assessment methods for European continent. The impact categories outlined for discussion here are human health, global warming and ecotoxicity. The analysis results reveal that the gold industry is vulnerable for the environment due to waste emission and similar result retained by silver mines a little bit. But copper, lead, manganese and zinc mining processes and industries are environment friendly in terms of metal extraction technologies and waste emissions.

Process to separate alkali metal salts from alkali metal reacted hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Gordon, John Howard; Alvare, Javier; Larsen, Dennis; Killpack, Jeff

2017-06-27

A process to facilitate gravimetric separation of alkali metal salts, such as alkali metal sulfides and polysulfides, from alkali metal reacted hydrocarbons. The disclosed process is part of a method of upgrading a hydrocarbon feedstock by removing heteroatoms and/or one or more heavy metals from the hydrocarbon feedstock composition. This method reacts the oil feedstock with an alkali metal and an upgradant hydrocarbon. The alkali metal reacts with a portion of the heteroatoms and/or one or more heavy metals to form an inorganic phase containing alkali metal salts and reduced heavy metals, and an upgraded hydrocarbon feedstock. The inorganic phase may be gravimetrically separated from the upgraded hydrocarbon feedstock after mixing at a temperature between about 350.degree. C. to 400.degree. C. for a time period between about 15 minutes and 2 hours.

Method of processing radioactive metal wastes

International Nuclear Information System (INIS)

Inoue, Yoichi; Kitagawa, Kazuo; Tsuzura, Katsuhiko.

1980-01-01

Purpose: To enable long and safety storage for radioactive metal wastes such as used fuel cans after the procession or used pipe, instruments and the likes polluted with various radioactive substances, by compacting them to solidify. Method: Metal wastes such as used fuel cans, which have been cut shorter and reprocessed, are pressed into generally hexagonal blocks. The block is charged in a capsule of a hexagonal cross section made of non-gas permeable materials such as soft steels, stainless steels and the likes. Then, the capsule is subjected to static hydraulic hot pressing as it is or after deaeration and sealing. While various combinations are possible for temperature, pressure and time as the conditions for the static hydraulic hot pressing, dense block with no residual gas pores can be obtained, for example, under the conditions of 900 0 C, 1000 Kg/cm 2 and one hour where the wastes are composed of zircaloy. (Kawakami, Y.)

Heavy metals contamination and their risk assessment around the abandoned base metals and Au-Ag mines in Korea

Science.gov (United States)

Chon, Hyo-Taek

2017-04-01

Heavy metals contamination in the areas of abandoned Au-Ag and base metal mines in Korea was investigated in order to assess the level of metal pollution, and to draw general summaries about the fate of toxic heavy metals in different environments. Efforts have been made to compare the level of heavy metals, chemical forms, and plant uptake of heavy metals in each mine site. In the base-metals mine areas, significant levels of Cd, Cu, Pb and Zn were found in mine dump soils developed over mine waste materials and tailings. Leafy vegetables tend to accumulate heavy metals(in particular, Cd and Zn) higher than other crop plants, and high metal concentrations in rice crops may affect the local residents' health. In the Au-Ag mining areas, arsenic would be the most characteristic contaminant in the nearby environment. Arsenic and heavy metals were found to be mainly associated with sulfide gangue minerals, and the mobility of these metals would be enhanced by the effect of continuing weathering and oxidation. According to the sequential extraction of metals in soils, most heavy metals were identified as non-residual chemical forms, and those are very susceptible to the change of ambient conditions of a nearby environment. The concept of pollution index(PI) of soils gives important information on the extent and degree of multi-element contamination, and can be applied to the evaluation of mine soils before their agricultural use and remediation. The risk assessment process comprising exposure assessment, dose-response assessment, and risk characterization was discussed, and the results of non-cancer risk of As, Cd, and Zn, and those of cancer risk of As were suggested.

Mapping Potential Areas For Gold And Base Metals Mineralization In Southeastern Desert, Egypt: An Approach By Using Remote Sensing And GIS

International Nuclear Information System (INIS)

ElFouly, A.; Salem, H.

2003-01-01

Integration of Landsat-Thematic Mapper (TM), aero magnetic data, structural geology along with the known mineralization occurrences in the area are mainly the factors used to recognize favorable sites for structurally controlled mineralization at the northern part of the southeastern Desert of Egypt. Two knowledge-driven models were constructed based on a conceptual gold exploration model. The Density of Lineament Intersection (DLI) results from this study along with Dempster-Shafer (D-S) Belief approach show good results in delineating favorable mineralization areas. The basic assignment probability maps for the heat source, strong magnetism, hydrothermal alteration, geologic structure, and known mineralization occurrences in the area are the main D-S Belief approach recognition criteria component used for mineral exploration in the study area. The DLI method is maximizing the use of Landsat remote sensing data that could be used efficiently in the exploration for structurally controlled hydrothermal related mineralization. The DLI method results show higher resolution and accurate results for gold and base metals exploration. The high favorability areas by using the DLI method is 2196 Km 2 which are concise area than the D-S Belief approach for about 3976.5 Km 2 . These results are useful to be a strong base for planning accurate exploration program. The potential favorability maps of gold and base metals ore deposits from the northern part of the South Eastern Desert predicted the known areas of mineralization as well as identified high potential areas not known before with mineralization for future exploration

Extraterrestrial Metals Processing, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The Extraterrestrial Metals Processing (EMP) system produces iron, silicon, and light metals from Mars, Moon, or asteroid resources in support of advanced human...

Posibility for application of froth separation process in beneficiation of raw minerals

Directory of Open Access Journals (Sweden)

František Tichánek

2005-11-01

Full Text Available Froth separation belongs to newer flotation methods that are suitable for the separation of fine-grained raw materials whose size is too big for regular flotation. The technology of coarse-grained flotation has a significant economical effect because it allows a decrease in the costs for mineral processing. The article concerneds the posibility of using the froth separation process during the mineral processing of bituminous coal.

Polymer derived non-oxide ceramics modified with late transition metals.

Science.gov (United States)

Zaheer, Muhammad; Schmalz, Thomas; Motz, Günter; Kempe, Rhett

2012-08-07

This tutorial review highlights the methods for the preparation of metal modified precursor derived ceramics (PDCs) and concentrates on the rare non-oxide systems enhanced with late transition metals. In addition to the main synthetic strategies for modified SiC and SiCN ceramics, an overview of the morphologies, structures and compositions of both, ceramic materials and metal (nano) particles, is presented. Potential magnetic and catalytic applications have been discussed for the so manufactured metal containing non-oxide ceramics.

Growth and Filling Regularities of Filamentary Channels in Non-Metallic Inorganic Coatings Under Anodic Oxidation of Valve Metals. Mathematical Modeling

Science.gov (United States)

Mamaev, A. I.; Mamaeva, V. A.; Kolenchin, N. F.; Chubenko, A. K.; Kovalskaya, Ya. B.; Dolgova, Yu. N.; Beletskaya, E. Yu.

2015-12-01

Theoretical models are developed for growth and filling processes in filamentary channels of nanostructured non-metallic coatings produced by anodizing and microplasma oxidation. Graphical concentration distributions are obtained for channel-reacting anions, cations, and sparingly soluble reaction products depending on the time of electric current transmission and the length of the filamentary channel. Graphical distributions of the front moving velocity for the sparingly soluble compound are presented. The resulting model representation increases the understanding of the anodic process nature and can be used for a description and prediction of porous anodic film growth and filling. It is shown that the character of the filamentary channel growth and filling causes a variety of processes determining the textured metal - nonmetallic inorganic coating phase boundary formation.

Cancrinite-group minerals behavior at non-ambient conditions

Science.gov (United States)

Lotti, Paolo; Gatta, G. Diego; Kahlenberg, Volker; Merlini, Marco; Alvaro, Matteo; Cámara, Fernando

2014-05-01

; vishnevite has KV 0 = 49(2) GPa; balliranoite has KV 0 = 48(3) GPa and αV,293K = 4.6(4)·10-5 K-1; davyne has KV 0 = 46.5(11) GPa and αV,293K = 4.2(4)·10-5 K-1). However, these minerals show different thermo-elastic anisotropy schemes, more pronounced in the cancrinite-subgroup minerals. This behavior is governed by different deformation mechanisms of the crystal structure, which likely reflect the different coordination environments of the cage-cations between the minerals of the cancrinite- and davyne-subgroups (i.e. Na+ and Ca2+, respectively). In addition, a P -induced re-organization of the extraframework population is observed, in vishnevite, at P ≥ 3.5 GPa, suggesting that the channel-constituents can also affect the elastic and structural behavior and the phase stability of these minerals at non-ambient conditions. Besides common features likely ascribable to the [CAN]-topology, the nature of the extraframework population appears to control significantly the (P ,T)-induced structure evolution and thermo-elastic behavior of the cancrinite-group compounds. PL, GDG and MM acknowledge the Italian Ministry of Education, MIUR-Project: 'Futuro in Ricerca 2012 - ImPACT- RBFR12CLQD'. MA acknowledges the ERC starting grant N. 307322 to FN.

Studies on the optimization of deformation processed metal metal matrix composites

Energy Technology Data Exchange (ETDEWEB)

Ellis, Tim W. [Iowa State Univ., Ames, IA (United States)

1994-01-04

A methodology for the production of deformation processed metal metal matrix composites from hyper-eutectic copper-chromium alloys was developed. This methodology was derived from a basic study of the precipitation phenomena in these alloys encompassing evaluation of microstructural, electrical, and mechanical properties. The methodology developed produces material with a superior combination of electrical and mechanical properties compared to those presently available in commercial alloys. New and novel alloying procedures were investigated to extend the range of production methods available for these material. These studies focused on the use of High Pressure Gas Atomization and the development of new containment technologies for the liquid alloy. This allowed the production of alloys with a much more refined starting microstructure and lower contamination than available by other methods. The knowledge gained in the previous studies was used to develop two completely new families of deformation processed metal metal matrix composites. These composites are based on immissible alloys with yttrium and magnesium matrices and refractory metal reinforcement. This work extends the physical property range available in deformation processed metal metal matrix composites. Additionally, it also represents new ways to apply these metals in engineering applications.

Predicting toxic heavy metal movements in upper Sanyati catchment ...

African Journals Online (AJOL)

Water samples from boreholes located in areas where mining, mineral processing and agricultural activities were dominant, yielded the highest values of toxic heavy metals. Dilution Attenuation Factor (DAF) for each toxic heavy metal was calculated to observe metal behaviour along the contaminant path for each season.

Determinants of Electricity Demand in Nonmetallic Mineral Products Industry: Evidence from a Comparative Study of Japan and China

Directory of Open Access Journals (Sweden)

Gang Du

2015-06-01

Full Text Available Electricity intensity is an important indicator for measuring production efficiency. A comparative study could offer a new perspective on investigating determinants of electricity demand. The Japanese non-metallic mineral products industry is chosen as the object for comparison considering its representative position in production efficiency. By adopting the cointegration model, this paper examines influencing factors of electricity demand in Japanese and Chinese non-metallic mineral products industries under the same framework. Results indicate that although economic growth and industrial development stages are different between the two countries, major factors that affect the sectoral energy consumption are the same. Specifically, economic growth and industrial activity contribute to the growth of sectoral electricity consumption, while R&D intensity, per capita productivity and electricity price are contributors to the decline of sectoral electricity consumption. Finally, in order to further investigate the development trend of sectoral electricity demand, future electricity consumption and conservation potential are predicted under different scenarios. Electricity demand of the Chinese non-metallic mineral products industry is predicted to be 680.53 TWh (terawatt-hours in 2020 and the sectoral electricity conservation potentials are estimated to be 118.26 TWh and 216.25 TWh under the moderate and advanced electricity-saving scenarios, respectively.

Guangxi non-ferrous metal industry speeding up its restructuring

Institute of Scientific and Technical Information of China (English)

2007-01-01

<正>Non-ferrous metal industry in Guangxi takes an important position in China.However,the waste of resources is severe due to its simple industrial structure,small size of enterprises, sloppy technology,scattered layout,obstructed market and indiscriminate mining.Starting from last year,Guangxi began the project of building a world-influential non-ferrous metal

Mineralization of 2-chlorophenol by sequential electrochemical reductive dechlorination and biological processes

Energy Technology Data Exchange (ETDEWEB)

Arellano-González, Miguel Ángel; González, Ignacio [Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Química, Av. San Rafael Atlixco No. 186, Col. Vicentina, 09340 Mexico D.F. (Mexico); Texier, Anne-Claire, E-mail: actx@xanum.uam.mx [Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Biotecnología, Av. San Rafael Atlixco No. 186, Col. Vicentina, 09340 Mexico, D.F. (Mexico)

2016-08-15

Highlights: • Dechlorination of 2-chlorophenol to phenol was 100% efficient on Pd-Ni/Ti electrode. • An ECCOCEL reactor was efficient and selective to obtain phenol from 2-chlorophenol. • Phenol was totally mineralized in a coupled denitrifying biorreactor. • Global time of 2-chlorophenol mineralization in the combined system was 7.5 h. - Abstract: In this work, a novel approach was applied to obtain the mineralization of 2-chlorophenol (2-CP) in an electrochemical-biological combined system where an electrocatalytic dehydrogenation process (reductive dechlorination) was coupled to a biological denitrification process. Reductive dechlorination of 2-CP was conducted in an ECCOCEL-type reactor on a Pd-Ni/Ti electrode at a potential of −0.40 V vs Ag/AgCl{sub (s)}/KCl{sub (sat)}, achieving 100 percent transformation of 2-CP into phenol. The electrochemically pretreated effluent was fed to a rotating cylinder denitrifying bioreactor where the totality of phenol was mineralized by denitrification, obtaining CO{sub 2} and N{sub 2} as the end products. The total time required for 2-CP mineralization in the combined electrochemical-biological process was 7.5 h. This value is close to those previously reported for electrochemical and advanced oxidation processes but in this case, an efficient process was obtained without accumulation of by-products or generation of excessive energy costs due to the selective electrochemical pretreatment. This study showed that the use of electrochemical reductive pretreatment combined with biological processes could be a promising technology for the removal of recalcitrant molecules, such as chlorophenols, from wastewaters by more efficient, rapid, and environmentally friendly processes.

Acid lixiviation of phophorite minerals for uranium extraction

International Nuclear Information System (INIS)

Linzama, H.; Rivas, J.

1988-01-01

Lixiviation studies of the phosphorite mineral, found in the north of Chile, using sulfuric acid solutions are described. These minerals contain 62.0 ppm of Uranium, 24% of Silice, 18.9% of P 2 O 5 and other metal-oxides. The influence of the acid concentration, the amount of acid used, granulometry, and the lixiviation yield as a function of the H 3 PO 4 and uranium concentrations was evaluated. In addition, the thermodinamic parameters of the lixiviation process were also evaluated. (author) [pt

On the Sustainability and Progress of Energy Neutral Mineral Processing

Directory of Open Access Journals (Sweden)

Frederik Reitsma

2018-01-01

Full Text Available A number of primary ores such as phosphate rock, gold-, copper- and rare earth ores contain considerable amounts of accompanying uranium and other critical materials. Energy neutral mineral processing is the extraction of unconventional uranium during primary ore processing to use it, after enrichment and fuel production, to generate greenhouse gas lean energy in a nuclear reactor. Energy neutrality is reached if the energy produced from the extracted uranium is equal to or larger than the energy required for primary ore processing, uranium extraction, -conversion, -enrichment and -fuel production. This work discusses the sustainability of energy neutral mineral processing and provides an overview of the current progress of a multinational research project on that topic conducted under the umbrella of the International Atomic Energy Agency.

21 CFR 888.3120 - Ankle joint metal/polymer non-constrained cemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ankle joint metal/polymer non-constrained cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3120 Ankle joint metal/polymer non-constrained cemented prosthesis. (a) Identification. An ankle joint metal/polymer non...

Atmospherically deposited trace metals from bulk mineral concentrate port operations.

Science.gov (United States)

Taylor, Mark Patrick

2015-05-15

Although metal exposures in the environment have declined over the last two decades, certain activities and locations still present a risk of harm to human health. This study examines environmental dust metal and metalloid hazards (arsenic, cadmium, lead and nickel) associated with bulk mineral transport, loading and unloading port operations in public locations and children's playgrounds in the inner city of Townsville, northern Queensland. The mean increase in lead on post-play hand wipes (965 μg/m(2)/day) across all sites was more than 10-times the mean pre-play loadings (95 μg/m(2)/day). Maximum loading values after a 10-minute play period were 3012 μg/m(2), more than seven times the goal of 400 μg/m(2) used by the Government of Western Australia (2011). Maximum daily nickel post-play hand loadings (404 μg/m(2)) were more than 26 times above the German Federal Immission Control Act 2002 annual benchmark of 15 μg/m(2)/day. Repeat sampling over the 5-day study period showed that hands and surfaces were re-contaminated daily from the deposition of metal-rich atmospheric dusts. Lead isotopic composition analysis of dust wipes ((208)Pb/(207)Pb and (206)Pb/(207)Pb) showed that surface dust lead was similar to Mount Isa type ores, which are exported through the Port of Townsville. While dust metal contaminant loadings are lower than other mining and smelting towns in Australia, they exceeded national and international benchmarks for environmental quality. The lessons from this study are clear - even where operations are considered acceptable by managing authorities, targeted assessment and monitoring can be used to evaluate whether current management practices are truly best practice. Reassessment can identify opportunities for improvement and maximum environmental and human health protection. Copyright © 2015 Elsevier B.V. All rights reserved.

Self-Ordering and Complexity in Epizonal Mineral Deposits

Science.gov (United States)

Henley, Richard W.; Berger, Byron R.

Epizonal base and precious metal deposits makeup a range of familiar deposit styles including porphyry copper-gold, epithermal veins and stockworks, carbonate-replacement deposits, and polymetallic volcanic rock-hosted (VHMS) deposits. They occur along convergent plate margins and are invariably associated directly with active faults and volcanism. They are complex in form, variable in their characteristics at all scales, and highly localized in the earth's crust. More than a century of detailed research has provided an extensive base of observational data characterizing these deposits, from their regional setting to the fluid and isotope chemistry of mineral deposition. This has led to a broad understanding of the large-scale hydrothermal systems within which they form. Low salinity vapor, released by magma crystallization and dispersed into vigorously convecting groundwater systems, is recognized as a principal source of metals and the gases that control redox conditions within systems. The temperature and pressure of the ambient fluid anywhere within these systems is close to its vapor-liquid phase boundary, and mineral deposition is a consequence of short timescale perturbations generated by localized release of crustal stress. However, a review of occurrence data raises questions about ore formation that are not addressed by traditional genetic models. For example, what are the origins of banding in epithermal veins, and what controls the frequency of oscillatory lamination? What controls where the phenomenon of mineralization occurs, and why are some porphyry deposits, for example, so much larger than others? The distinctive, self-organized characteristics of epizonal deposits are shown to be the result of repetitive coupling of fracture dilation consequent on brittle failure, phase separation ("boiling"), and heat transfer between fluid and host rock. Process coupling substantially increases solute concentrations and triggers fast, far

Geophysical aspects of underground fluid dynamics and mineral transformation process

Science.gov (United States)

Khramchenkov, Maxim; Khramchenkov, Eduard

2014-05-01

The description of processes of mass exchange between fluid and poly-minerals material in porous media from various kinds of rocks (primarily, sedimentary rocks) have been examined. It was shown that in some important cases there is a storage equation of non-linear diffusion equation type. In addition, process of filtration in un-swelling soils, swelling porous rocks and coupled process of consolidation and chemical interaction between fluid and particles material were considered. In the latter case equations of physical-chemical mechanics of conservation of mass for fluid and particles material were used. As it is well known, the mechanics of porous media is theoretical basis of such branches of science as rock mechanics, soil physics and so on. But at the same moment some complex processes in the geosystems lacks full theoretical description. The example of such processes is metamorphosis of rocks and correspondent variations of stress-strain state. In such processes chemical transformation of solid and fluid components, heat release and absorption, phase transitions, rock destruction occurs. Extensive usage of computational resources in limits of traditional models of the mechanics of porous media cannot guarantee full correctness of obtained models and results. The process of rocks consolidation which happens due to filtration of underground fluids is described from the position of rock mechanics. As an additional impact, let us consider the porous media consolidating under the weight of overlying rock with coupled complex geological processes, as a continuous porous medium of variable mass. Problems of obtaining of correct storage equations for coupled processes of consolidation and mass exchange between underground fluid and skeleton material are often met in catagenesi processes description. The example of such processes is metamorphosis of rocks and correspondent variations of stress-strain state. In such processes chemical transformation of solid and fluid

Conflict minerals from the Democratic Republic of the Congo: global tungsten processing plants, a critical part of the tungsten supply chain

Science.gov (United States)

Bermúdez-Lugo, Omayra

2014-01-01

The U.S. Geological Survey (USGS) analyzes supply chains to identify and define major components of mineral and material flows from ore extraction, through intermediate forms, to a final product. Two major reasons necessitate these analyses: (1) to identify risks associated with the supply of critical and strategic minerals to the United States and (2) to provide greater supply chain transparency so that policymakers have the information necessary to ensure domestic legislation compliance. This fact sheet focuses on the latter. The USGS National Minerals Information Center has been asked by governmental and non-governmental organizations to provide information on tin, tantalum, tungsten, and gold (collectively known as “3TG minerals”) processing facilities worldwide in response to U.S. legislation aimed at removing the link between the trade in these minerals and civil unrest in the Democratic Republic of the Congo. Post beneficiation processing plants (smelters and refineries) of 3TG mineral ores and concentrates were identified by company and industry association representatives as being the link in the 3TG mineral supply chain through which these minerals can be traced to their source of origin (mine); determining the point of origin is critical to establishing a transparent conflict mineral supply chain. This fact sheet, the first in a series of 3TG mineral fact sheets, focuses on the tungsten supply chain by listing plants that consume tungsten concentrates to produce ammonium paratungstate and ferrotungsten worldwide.

Trace Metal Levels in Raw and Heat Processed Nigerian Staple ...

African Journals Online (AJOL)

The levels of some trace metals (Fe, Zn, Cu, Ni, Cd) were quantitatively determined in raw and heat processed staple food cultivars (yam, cassava, cocoyam and maize) from oil producing areas of part of the Niger Delta and compared with a non-oil producing area of Ebonyi State as control. The survey was conducted to ...

[Balneotherapeutics of non-alcoholic fatty liver disease with the use of the Essentuki-type drinking mineral waters].

Science.gov (United States)

Fedorova, T E; Efimenko, N V; Kaĭsinova, A S

2012-01-01

The objective of the present work was to estimate the effectiveness of combined spa-and-resort treatment with the use of the Essentuki-type drinking mineral waters for the patients presenting with non-alcoholic fatty liver disease. A total of 40 patients presening with non-alcoholic fatty liver disease (NOFLD) were available for the examination. The study has demonstrated positive dynamics of clinical symptoms and results of liver functional tests, characteristics of intrahepatic dynamics, lipid metabolism, antioxidant hemostais, and the hormonal status of the patients with non-alcoholic fatty liver disease. The intake of the Essentuki-type drinking mineral waters promoted normalization of adiponectin and leptin levels in conjunction with the reduction in the degree of insulin resistance, i.e., the key pathogenetic factors responsible for hepatic steatosis and non-alcoholic steatohepatitis. It is concluded that the Essentuki-type drinking mineral waters may be recommended for the inclusion in the combined treatment and prevention of the progression of non-alcoholic fatty liver disease.

Management of waste from mining and minerals processing

International Nuclear Information System (INIS)

Kraus, W.

2000-01-01

Growing attention has been paid to exposures to enhanced natural radiation in the last decade. One important problem is the management of waste from mining and minerals processing. The inconsistencies in the relevant approaches may partly be a consequence of the fact that feasible but too expensive measures to reduce doses may be unreasonable because of their socio-economic impacts. Although in principle airborne and liquid effluents belong to the definition of radioactive waste they are not discussed in this paper: There are three different basic waste types: -Waste rock piles and tailings from uranium mining and milling as practices. -Wastes created by mining and processing of minerals where the enhanced radioactivity is incidental to the work, e.g. phosphate industry, processing of metal ores and zircon sands, manufacture of rare earths, manufacture and use of thorium compounds, oil and gas extraction industry, combustion of coal. (Amounts of wastes and their activity concentrations are very different in different countries. Most of these 'practices' already exist, and they might be included in the radiation protection system like an intervention situation. In the European Basic Safety Standards they are called 'work activities'.) -Residues from former mining and processing, where radiation protection had not or inadequately been observed, as pure intervention situations. To solve radiation protection problems with regard to enhanced natural radioactivity a flexible approach is to be preferred. After an overview of the problems and their significance in a country work activities and intervention situations of concern should be identified. Compliance with established dose criteria should be achieved by simple intervention measures. Only if this is not possible a radiation protection system as for practices should be applied. At present efforts are focussed on occupational exposures. The management of wastes should analogously and simultaneously be included in new

Effect of organosolv and soda pulping processes on the metals content of non-woody pulps.

Science.gov (United States)

González, M; Cantón, L; Rodríguez, A; Labidi, J

2008-09-01

In this work the effect of different pulping processes (ethyleneglycol, diethyleneglycol, ethanolamine and soda) of tow abounded raw materials (empty fruit bunches - EFB and rice straw) on the ash, silicates and metals (Fe, Zn, Cu, Pb, Mn, Ni and Cd) content of the obtained pulps have been studied. Results showed that pulps obtained by diethyleneglycol pulping process presented lower metals content (756 microg/g and 501 microg/g for EFB and rice straw pulp, respectively) than soda pulps (984 microg/g and 889 microg/g). Ethanolamine pulps presented values of holocellulose (74% and 77% for EFB and rice straw pulp, respectively), alpha-cellulose (74% and 69%), kappa number (18.7 and 18.5) and viscosity (612 and 90 6ml/g) similar to those of soda pulp, and lower lignin contents (11% and 12%).

A concise review of nanoscopic aspects of bioleaching bacteria-mineral interactions.

Science.gov (United States)

Diao, Mengxue; Taran, Elena; Mahler, Stephen; Nguyen, Anh V

2014-10-01

Bioleaching is a technology for the recovery of metals from minerals by means of microorganisms, which accelerate the oxidative dissolution of the mineral by regenerating ferric ions. Bioleaching processes take place at the interface of bacteria, sulfide mineral and leaching solution. The fundamental forces between a bioleaching bacterium and mineral surface are central to understanding the intricacies of interfacial phenomena, such as bacterial adhesion or detachment from minerals and the mineral dissolution. This review focuses on the current state of knowledge in the colloidal aspect of bacteria-mineral interactions, particularly for bioleaching bacteria. Special consideration is given to the microscopic structure of bacterial cells and the atomic force microscopy technique used in the quantification of fundamental interaction forces at nanoscale. Copyright © 2014 Elsevier B.V. All rights reserved.

Metal sorption on kaolinite

International Nuclear Information System (INIS)

Westrich, H.R.; Brady, P.V.; Cygan, R.T.; Nagy, K.L.; Anderson, H.L.

1997-01-01

A key issue in performance assessment of low-level radioactive waste sites is predicting the transport and retardation of radionuclides through local soils under a variety of hydrologic and geochemical conditions. Improved transport codes should include a mechanistic model of radionuclide retardation. The authors have been investigating metal sorption (Cs + , Sr 2+ , and Ba 2+ ) on a simple clay mineral (kaolinite) to better understand the geochemical interactions of common soil minerals with contaminated groundwaters. These studies include detailed characterizations of kaolinite surfaces, experimental adsorption measurements, surface complexation modeling, and theoretical simulations of cation sorption. The aluminol edge (010) site has been identified as the most likely site for metal sorption on kaolinite in natural solutions. Relative metal binding strengths decrease from Ba 2+ to Sr 2+ to Cs + , with some portion sorbed on both kaolinite edges and basal surfaces. Some Cs + also appears to be irreversibly sorbed on both sites. Molecular dynamics simulations suggest that Cs + is sorbed at aluminol (010) edge sites as an inner-sphere complex and weakly sorbed as an outer-sphere complex on (001) basal surfaces. These results provide the basis to understand and predict metal sorption onto kaolinite, and a framework to characterize sorption processes on more complex clay minerals

Outlook 96: Minerals and Energy

International Nuclear Information System (INIS)

1996-01-01

Papers discussing the future of Australia's minerals and energy are presented under the following headings: Australia in the global minerals and energy markets; minerals exploration; steelmaking raw materials; aluminium and alumina; gold; nickel; base metals; titanium minerals; energy for a sustainable future; electricity; electricity in Asia; crude oil; coal trade; natural gas in Australia and uranium. Relevant papers are individually indexed/abstracted. Tabs., figs., refs

Environmental Pollution by Heavy Metals in the Soil Resources of Zakhur District, as Examined through Geological Processes

International Nuclear Information System (INIS)

Jalilzadeh, J.; Siahcheshm, K.

2016-01-01

In order to assess soil pollution formed on the alteration zones of Zakhur District, we used 20 ICP-MS analyses. Argillic, argillic-phyllic, advanced argillic, silicic along with Cu, Fe, Pb, Zn, Co, Ni, Au and Ag are the most important decentralized natural resource contaminating agents that have formed extensive heavy/toxic metal haloes in this area. Diverse environmental pollution indices (e.g. geo-accumulation-Igeo, modified contamination degree- mCd and potential ecological risk- RI) show that the leve of environmental pollution risk of Pb is considerable and, as in different alteration zones, quaternary sediments are also very high. Soils highly contaminated with sulfur result in the high sulfide mineralization character of the alteration zones in Zakhur District. Calculations of the mass changes in argillic and silisic zones indicate enrichment by Cr, Ni, As, Pb and S and loss of Hg and Cd. Besides the positive correlation of heavy metals with each other, there are significant correlations between them and Mn and Al which may have occurred due to the adsorption processes by manganese, iron oxides and/or clay minerals.

Fabrication of subwavelength metallic structures by using a metal direct imprinting process

International Nuclear Information System (INIS)

Hsieh, C W; Hsiung, H Y; Lu, Y T; Sung, C K; Wang, W H

2007-01-01

This work employs a metal direct imprinting process, which possesses the characteristics of simplicity, low-cost and high resolution, for the fabrication of subwavelength structures on a metallic thin film. Herein, the mould featuring periodic line structures is manufactured by using E-beam lithography and followed by a dry etching process; meanwhile, the thin film is fabricated by sputtering Al on a silicon substrate. AFM section analyses are employed to measure imprinting depths of the subwavelength metallic structures and it is found that the uniformity of the imprinting depths is affected by the designed patterns, the material property of thin film and mould deformation. The process temperature and the mould filling that influence the transferred quality are investigated. In addition, TEM is also utilized to examine defects in the subwavelength metallic structures. Finally, good quality subwavelength metallic structures are fabricated under a pressure of 300 MPa for 60 s at room temperature. In this study, we have demonstrated that subwavelength metallic structures with a minimum linewidth of less than 100 nm on the Al thin film are successfully constructed by the metal direct imprinting process

A Fully Non-Metallic Gas Turbine Engine Enabled by Additive Manufacturing

Science.gov (United States)

Grady, Joseph E.; Halbig, Michael C.; Singh, Mrityunjay

2015-01-01

In a NASA Aeronautics Research Institute (NARI) sponsored program entitled "A Fully Non-Metallic Gas Turbine Engine Enabled by Additive Manufacturing", evaluation of emerging materials and additive manufacturing technologies was carried out. These technologies may enable fully non-metallic gas turbine engines in the future. This paper highlights the results of engine system trade studies which were carried out to estimate reduction in engine emissions and fuel burn enabled due to advanced materials and manufacturing processes. A number of key engine components were identified in which advanced materials and additive manufacturing processes would provide the most significant benefits to engine operation. In addition, feasibility of using additive manufacturing technologies to fabricate gas turbine engine components from polymer and ceramic matrix composite were demonstrated. A wide variety of prototype components (inlet guide vanes (IGV), acoustic liners, engine access door) were additively manufactured using high temperature polymer materials. Ceramic matrix composite components included first stage nozzle segments and high pressure turbine nozzle segments for a cooled doublet vane. In addition, IGVs and acoustic liners were tested in simulated engine conditions in test rigs. The test results are reported and discussed in detail.

Metal oxides, clay minerals and charcoal determine the composition of microbial communities in matured artificial soils and their response to phenanthrene.

Science.gov (United States)

Babin, Doreen; Ding, Guo-Chun; Pronk, Geertje Johanna; Heister, Katja; Kögel-Knabner, Ingrid; Smalla, Kornelia

2013-10-01

Microbial communities in soil reside in a highly heterogeneous habitat where diverse mineral surfaces, complex organic matter and microorganisms interact with each other. This study aimed to elucidate the long-term effect of the soil mineral composition and charcoal on the microbial community composition established in matured artificial soils and their response to phenanthrene. One year after adding sterile manure to different artificial soils and inoculating microorganisms from a Cambisol, the matured soils were spiked with phenanthrene or not and incubated for another 70 days. 16S rRNA gene and internal transcribed spacer fragments amplified from total community DNA were analyzed by denaturing gradient gel electrophoresis. Metal oxides and clay minerals and to a lesser extent charcoal influenced the microbial community composition. Changes in the bacterial community composition in response to phenanthrene differed depending on the mineral composition and presence of charcoal, while no shifts in the fungal community composition were observed. The abundance of ring-hydroxylating dioxygenase genes was increased in phenanthrene-spiked soils except for charcoal-containing soils. Here we show that the formation of biogeochemical interfaces in soil is an ongoing process and that different properties present in artificial soils influenced the bacterial response to the phenanthrene spike. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Recovery and recycling of aluminum, copper, and precious metals from dismantled weapon components

International Nuclear Information System (INIS)

Gundiler, I.H.; Lutz, J.D.; Wheelis, W.T.

1994-01-01

Sandia National Laboratories (SNL) is tasked to support The Department of Energy in the dismantlement and disposal of SNL designed weapon components. These components are sealed in a potting compound, and contain heavy metals, explosive, radioactive, and toxic materials. SNL developed a process to identify and remove the hazardous sub-components utilizing real-time radiography and abrasive water-jet cutting. The components were then crushed, granulated, screened, and separated into an aluminum and a precious-and-base-metals fraction using air-tables. Plastics were further cleaned for disposal as non-hazardous waste. New Mexico Bureau of Mines and Mineral Resources assisted SNL in investigation of size-reduction and separation technologies

Mineral exploration with ERTS imagery. [Colorado

Science.gov (United States)

Nicolais, S. M.

1974-01-01

Ten potential target areas for metallic mineral exploration were selected on the basis of a photo-lineament interpretation of the ERTS image 1172-17141 in central Colorado. An evaluation of bias indicated that prior geologic knowledge of the region had little, if any, effect on target selection. In addition, a contoured plot of the frequency of photo-lineament intersections was made to determine what relationships exist between the photo-lineaments and mineral districts. Comparison of this plot with a plot of the mineral districts indicates that areas with a high frequency of intersections commonly coincide with known mineral districts. The results of this experiment suggest that photo-lineaments are fractures or fracture-controlled features, and their distribution may be a guide to metallic mineral deposits in Colorado, and probably other areas as well.

A review of silver-rich mineral deposits and their metallogeny

Science.gov (United States)

Graybeal, Frederick T.; Vikre, Peter

2010-01-01

Mineral deposits with large inventories or high grades of silver are found in four genetic groups: (1) volcanogenic massive sulfide (VMS), (2) sedimentary exhalative (SEDEX), (3) lithogene, and, (4) magmatichydrothermal. Principal differences between the four groups relate to source rocks and regions, metal associations, process and timing of mineralization, and tectonic setting. These four groups may be subdivided into specific metal associations on ternary diagrams based on relative metal contents. The VMS deposits rarely contain more than 15,600 t Ag (500 Moz). Grades average 33 g/t Ag. Variable Ag- Pb-Zn-Cu-Au ± Sn concentrations are interpreted as having been derived both from shallow plutons and by leaching of the volcanic rock pile in regions of thin or no continental crust and the mineralization is syngenetic. Higher silver grades are associated with areas of abundant felsic volcanic rocks. The SEDEX deposits rarely contain more than 15,600 t Ag (500 Moz). Grades average 46 g/t Ag. Silver, lead, and zinc in relatively consistent proportions are leached from sedimentary rocks filling rift-related basins, where the continental crust is thin, and deposited as syngenetic to diagenetic massive sulfides. Pre-mineral volcanic rocks and their detritus may occur deep within the basin and gold is typically absent. Lithogene silver-rich deposits are epigenetic products of varying combinations of compaction, dewatering, meteoric water recharge, and metamorphism of rift basin-related clastic sedimentary and interbedded volcanic rocks. Individual deposits may contain more than 15,600 t Ag (500 Moz) at high grades. Ores are characterized by four well-defined metal associations, including Ag, Ag-Pb-Zn, Ag-Cu, and Ag-Co-Ni-U. Leaching, transport, and deposition of metals may occur both in specific sedimentary strata and other rock types adjacent to the rift. Multiple mineralizing events lasting 10 to 15 m.y., separated by as much as 1 b.y., may occur in a single basin

U-Pb age for some base-metal sulfide deposits in Ireland: genetic implications for Mississippi Valley-type mineralization

International Nuclear Information System (INIS)

Duane, M.J.; Welke, H.J.; Allsopp, H.L.

1986-01-01

Evidence is presented that links the timing of vein-type (Cu-Ag(U)) to stratiform Mississippi Valley-type (MVT, Pb-Zn) ore events in Ireland. The rare occurrence of pitchblende, coffinite(?), and brannerite mineralization, which is regarded as a precursor component to the sulfide mineralization in the Gortdrum deposit (Ireland), provides the first direct radiometric dating tool for these carbonate-hosted deposits. The U-Pb (340 +25/-20 Ma) and Pb-Pb (359 +/- 26 Ma) whole-rock ages constrain the uranium and base-metal mineralizing events to the Early Carboniferous. The data support a model according to which MVT and earlier uranium mineralization stages of some major ore bodies resulted from fracturing coincident with large basin-dewatering events. The Pb-Pb and concordia data are consistent with an Early Carboniferous age for the mineralization at Gortdrum and agree closely with a previously published Rb-Sr age of 359 +/- 22 Ma, obtained for Missouri glauconites. Furthermore, other comparative geologic data from Ireland and from North American MVT mineral provinces support a model of Pb-Zn-Cu(U) mobilization on a regional scale that implicates the later closing stages of the proto-Atlantic. 40 references, 3 figures, 1 table

Mesoporous metal oxides and processes for preparation thereof

Energy Technology Data Exchange (ETDEWEB)

Suib, Steven L.; Poyraz, Altug Suleyman

2018-03-06

A process for preparing a mesoporous metal oxide, i.e., transition metal oxide. Lanthanide metal oxide, a post-transition metal oxide and metalloid oxide. The process comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to form the mesoporous metal oxide. A mesoporous metal oxide prepared by the above process. A method of controlling nano-sized wall crystallinity and mesoporosity in mesoporous metal oxides. The method comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to control nano-sized wall crystallinity and mesoporosity in the mesoporous metal oxides. Mesoporous metal oxides and a method of tuning structural properties of mesoporous metal oxides.

The Measurement of Hardness and Elastic Modulus of non-Metallic Inclusions in Steely Welding Joints

Directory of Open Access Journals (Sweden)

Ignatova Anna

2015-08-01

Full Text Available Trunk pipelines work under a cyclic dynamical mechanical load because when oil or gas is pumped, the pressure constantly changes - pulsates. Therefore, the fatigue phenomenon is a common reason of accidents. The fatigue phenomenon more often happens in the zone of non-metallic inclusions concentration. To know how the characteristics of nonmetallic inclusions influence the probability of an accident the most modern research methods should be used. It is determined with the help of the modern research methods that the accident rate of welded joints of pipelines is mostly influenced by their morphological type, composition and size of nonmetallic inclusions, this effect is more important than the common level of pollution by non-metallic inclusions. The article presents the results of the investigations of welded joints, obtained after the use of different common welding materials. We used the methods, described in the state standards: scanning electronic microscopy, spectral microprobe analysis and nano-indentation. We found out that non-metallic inclusions act like stress concentrators because they shrink, forming a blank space between metal and nonmetallic inclusions; it strengthens the differential properties on this boundary. Nonmetallic inclusion is not fixed, it can move. The data that we have received mean that during welded joints’ contamination (with non-metallic inclusions monitoring process, more attention should be paid to the content of definite inclusions, but not to total contamination.

Mineral formation and organo-mineral controls on the bioavailability of carbon at the terrestrial-aquatic interface

Science.gov (United States)

Rod, K. A.; Smith, A. P.; Renslow, R.

2016-12-01

Recent evidence highlights the importance of organo-mineral interactions in regulating the source or sink capacity of soil. High surface area soils, such as allophane-rich or clay-rich soils, retain organic matter (OM) via sorption to mineral surfaces which can also contribute physical isolation in interlayer spaces. Despite the direct correlation between mineral surfaces and OM accumulation, the pedogenic processes controlling the abundance of reactive surface areas and their distribution in the mineral matrix remains unclear. As global soil temperatures rise, the dissolution of primary minerals and formation of new secondary minerals may be thermodynamically favored as part of soil weathering process. Newly formed minerals can supply surfaces for organo-metallic bonding and may, therefore, stabilize OM by surface bonding and physical exclusion. This is especially relevant in environments that intersect terrestrial and aquatic systems, such as the capillary fringe zone in riparian ecosystems. To test the mechanisms of mineral surface area protection of OM, we facilitated secondary precipitation of alumino-silicates in the presence of OM held at two different temperatures in natural Nisqually River sediments (Mt Rainier, WA). This was a three month reaction intended to simulate early pedogenesis. To tease out the influence of mineral surface area increase during pedogenesis, we incubated the sediments at two different soil moisture contents to induce biodegradation. We measured OM desorption, biodegradation, and the molecular composition of mineral-associated OM both prior to and following the temperature manipulation. To simulate the saturation of capillary fringe sediment and associated transport and reaction of OM, column experiments were conducted using the reacted sediments. More co-precipitation was observed in the 20°C solution compared to the 4°C reacted solution suggesting that warming trends alter mineral development and may remove more OM from solution

Do constructed wetlands remove metals or increase metal bioavailability?

Science.gov (United States)

Xu, Xiaoyu; Mills, Gary L

2018-07-15

The H-02 wetland was constructed to treat building process water and storm runoff water from the Tritium Processing Facility on the Department of Energy's Savannah River Site (Aiken, SC). Monthly monitoring of copper (Cu) and zinc (Zn) concentrations and water quality parameters in surface waters continued from 2014 to 2016. Metal speciation was modeled at each sampling occasion. Total Cu and Zn concentrations released to the effluent stream were below the NPDES limit, and the average removal efficiency was 65.9% for Cu and 71.1% for Zn. The metal-removal processes were found out to be seasonally regulated by sulfur cycling indicated by laboratory and model results. High temperature, adequate labile organic matter, and anaerobic conditions during the warm months (February to August) favored sulfate reduction that produced sulfide minerals to significantly remove metals. However, the dominant reaction in sulfur cycling shifted to sulfide oxidation during the cool months (September to next March). High concentrations of metal-organic complexes were observed, especially colloidal complexes of metal and fulvic acid (FA), demonstrating adsorption to organic matter became the primary process for metal removal. Meanwhile, the accumulation of metal-FA complexes in the wetland system will cause negative effects to the surrounding environment as they are biologically reactive, highly bioavailable, and can be easily taken up and transferred to ecosystems by trophic exchange. Copyright © 2018 Elsevier Ltd. All rights reserved.

Clean Air Act Standards and Guidelines for Mineral Processing

Science.gov (United States)

This page contains the stationary sources of air pollution for the mineral processing industries, and their corresponding air pollution regulations. To learn more about the regulations for each industry, just click on the links below.

Proceedings of the 39. annual meeting of the Canadian Mineral Processors : 2007

Energy Technology Data Exchange (ETDEWEB)

Folinsbee, J. [G and T Metallurgical Services, Kamloops, BC (Canada)] (comp.)

2007-07-01

This conference addressed a broad range of issues affecting the minerals and metals sector, including ore processing and human resource issues such as an aging workforce. In addition to a plenary session, the conference featured the following 6 sessions: (1) new projects and operating improvements, (2) comminution, (3) precious metals, (4) process applications 1, (5) process modelling and mineralogy and (6) process applications 2. The papers in the first session addressed topics such as Voisey's Bay Mill; grinding mill design for the Tenke Project; the Paracatu gold mine; ore characterization of the Aqqaluk deposit; and, improvements of circuit performance. The second session focused on grinding circuit modeling and design; SAG mill operations; matching motor to mill torque; interactions between slurry density and grinding media size; replacement of diatomaceous earth filter aid with alpha-cellulose at the Laronde Refinery; and, the Turbo Pulp Lifter. The session on precious metals discussed the reduction of free gold losses at the Kemess Mine; lead nitrate control in cyanidation; effect of operating variables in Knelson concentrators; Kelsey centrifugal jig; Gekko's gold ore treatment plants; and, the gravity recoverable gold test. The two sessions on process applications included papers on underground milling of uranium ores; infrared recognition of high sulphide and carbonaceous rocks after microwave heating; iron control in mineral processing; frother analysis; the use of passive sonar; new applications for biogenic sulphide reagent in hydrometallurgy and mineral processing; analytical surface chemistry; and, improvement of mass and value balance data from the statistical benchmark model. The final session included papers on validation of high fidelity simulation wear; the use of computational fluid dynamics and discrete element, flotation circuit design; mineralogical evaluation of Au-Sb-As mineralization from the AD-MW Zones; principal components

Process for the enhanced capture of heavy metal emissions

Science.gov (United States)

Biswas, Pratim; Wu, Chang-Yu

2001-01-01

This invention is directed to a process for forming a sorbent-metal complex. The process includes oxidizing a sorbent precursor and contacting the sorbent precursor with a metallic species. The process further includes chemically reacting the sorbent precursor and the metallic species, thereby forming a sorbent-metal complex. In one particular aspect of the invention, at least a portion of the sorbent precursor is transformed into sorbent particles during the oxidation step. These sorbent particles then are contacted with the metallic species and chemically reacted with the metallic species, thereby forming a sorbent-metal complex. Another aspect of the invention is directed to a process for forming a sorbent metal complex in a combustion system. The process includes introducing a sorbent precursor into a combustion system and subjecting the sorbent precursor to an elevated temperature sufficient to oxidize the sorbent precursor and transform the sorbent precursor into sorbent particles. The process further includes contacting the sorbent particles with a metallic species and exposing the sorbent particles and the metallic species to a complex-forming temperature whereby the metallic species reacts with the sorbent particles thereby forming a sorbent-metal complex under UV irradiation.

The Diesel Exhaust in Miners Study: IV. Estimating historical exposures to diesel exhaust in underground non-metal mining facilities.

Science.gov (United States)

Vermeulen, Roel; Coble, Joseph B; Lubin, Jay H; Portengen, Lützen; Blair, Aaron; Attfield, Michael D; Silverman, Debra T; Stewart, Patricia A

2010-10-01

We developed quantitative estimates of historical exposures to respirable elemental carbon (REC) for an epidemiologic study of mortality, including lung cancer, among diesel-exposed miners at eight non-metal mining facilities [the Diesel Exhaust in Miners Study (DEMS)]. Because there were no historical measurements of diesel exhaust (DE), historical REC (a component of DE) levels were estimated based on REC data from monitoring surveys conducted in 1998-2001 as part of the DEMS investigation. These values were adjusted for underground workers by carbon monoxide (CO) concentration trends in the mines derived from models of historical CO (another DE component) measurements and DE determinants such as engine horsepower (HP; 1 HP = 0.746 kW) and mine ventilation. CO was chosen to estimate historical changes because it was the most frequently measured DE component in our study facilities and it was found to correlate with REC exposure. Databases were constructed by facility and year with air sampling data and with information on the total rate of airflow exhausted from the underground operations in cubic feet per minute (CFM) (1 CFM = 0.0283 m³ min⁻¹), HP of the diesel equipment in use (ADJ HP), and other possible determinants. The ADJ HP purchased after 1990 (ADJ HP₁₉₉₀(+)) was also included to account for lower emissions from newer, cleaner engines. Facility-specific CO levels, relative to those in the DEMS survey year for each year back to the start of dieselization (1947-1967 depending on facility), were predicted based on models of observed CO concentrations and log-transformed (Ln) ADJ HP/CFM and Ln(ADJ HP₁₉₉₀(+)). The resulting temporal trends in relative CO levels were then multiplied by facility/department/job-specific REC estimates derived from the DEMS surveys personal measurements to obtain historical facility/department/job/year-specific REC exposure estimates. The facility-specific temporal trends of CO levels (and thus the REC

Processing method of radioactive metal wastes

International Nuclear Information System (INIS)

Uetake, Naoto; Urata, Megumu; Sato, Masao.

1985-01-01

Purpose: To reduce the volume and increase the density of radioactive metal wastes easily while preventing scattering of radioactivity and process them into suitable form to storage and treatment. Method: Metal wastes mainly composed of zirconium are discharged from nuclear power plants or fuel re-processing plants, and these metals such as zirconium and titanium vigorously react with hydrogen and rapidly diffuse as hydrides. Since the hydrides are extremely brittle and can be pulverized easily, they can be volume-reduced. However, since metal hydrides have no ductility, dehydrogenation is applied for the molding fabrication in view of the subsequent storage and processing. The dehydrogenation is easy like the hydrogenation and fine metal pieces can be molded in a small compression device. For the dehydrogenation, a temperature is slightly increased as compared with that in the hydrogenation, pressure is reduced through the vacuum evacuation system and the removed hydrogen is purified for reuse. The upper limit for the temperature of the hydrogenation is 680 0 C in order to prevent the scttering of radioactivity. (Kamimura, M.)

Use of non-hyperaccumulator plant species for the phytoextraction of heavy metals using chelating agents

Directory of Open Access Journals (Sweden)

Lucas Anjos Souza

2013-08-01

Full Text Available Soil contamination by heavy metals is a challenge faced by many countries, and engineering technologies to solve this problem are expensive and can cause negative impacts on the environment. One way to minimise the levels of heavy metals in the soil is to use plants that can absorb and accumulate heavy metals into harvestable parts, a process called phytoextraction. Typical plant species used in research involving phytoextraction are heavy metal hyperaccumulators, but plants from this group are not good biomass producers and grow more slowly than most species; thus, they have an important role in helping scientists understand the mechanisms involved in accumulating high amounts of heavy metals without developing symptoms or dying. However, because of their slow growth, it is not practical to use these species for phytoextraction. An alternative approach is to use non-hyperaccumulator plants assisted by chelating agents, which may improve the ability of plants to accumulate more heavy metals than they would naturally. Chelating agents can be synthetic or organic acids, and the advantages and disadvantages of their use in improving the phytoextraction potential of non-hyperaccumulator plants are discussed in this article. We hope to draw attention to ways to improve the phytoextraction potential of non-hyperaccumulator plants that produce a large amount of biomass and to stimulate more research on phytoextraction-inducing substances.

Incidence of non-lung solid cancers in Czech uranium miners: a case-cohort study.

Science.gov (United States)

Kulich, M; Reřicha, V; Reřicha, R; Shore, D L; Sandler, D P

2011-04-01

Uranium miners are chronically exposed to radon and its progeny, which are known to cause lung cancer and may be associated with leukemia. This study was undertaken to evaluate risk of non-lung solid cancers among uranium miners in Příbram region, Czech Republic. A retrospective stratified case-cohort study in a cohort of 22,816 underground miners who were employed between 1949 and 1975. All incident non-lung solid cancers were ascertained among miners who worked underground for at least 12 months (n=1020). A subcohort of 1707 subjects was randomly drawn from the same population by random sampling stratified on age. The follow-up period lasted from 1977 to 1996. Relative risks comparing 180 WLM (90th percentile) of cumulative lifetime radon exposure to 3 WLM (10th percentile) were 0.88 for all non-lung solid cancers combined (95% CI 0.73-1.04, n=1020), 0.87 for all digestive cancers (95% CI 0.69-1.09, n=561), 2.39 for gallbladder cancer (95% CI 0.52-10.98, n=13), 0.79 for larynx cancer (95% CI 0.38-1.64, n=62), 2.92 for malignant melanoma (95% CI 0.91-9.42, n=23), 0.84 for bladder cancer (95% CI 0.43-1.65, n=73), and 1.13 for kidney cancer (95% CI 0.62-2.04, n=66). No cancer type was significantly associated with radon exposure; only malignant melanoma and gallbladder cancer showed elevated but non-significant association with radon. Radon was not significantly associated with incidence of any cancer of interest, although a positive association of radon with malignant melanoma and gallbladder cancer cannot be entirely ruled out. Copyright © 2011 Elsevier Inc. All rights reserved.

21 CFR 888.3490 - Knee joint femorotibial metal/composite non-constrained cemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metal/composite non... § 888.3490 Knee joint femorotibial metal/composite non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/composite non-constrained cemented prosthesis is a device...

Controls on Mississippi Valley-Type Zn-Pb mineralization in Behabad district, Central Iran: Constraints from spatial and numerical analyses

Science.gov (United States)

Parsa, Mohammad; Maghsoudi, Abbas

2018-04-01

The Behabad district, located in the central Iranian microcontinent, contains numerous epigenetic stratabound carbonate-hosted Zn-Pb ore bodies. The mineralizations formed as fault, fracture and karst fillings in the Permian-Triassic formations, especially in Middle Triassic dolostones, and comprise mainly non-sulfides zinc ores. These are all interpreted as Mississippi Valley-type (MVT) base metal deposits. From an economic geological point of view, it is imperative to recognize the processes that have plausibly controlled the emplacement of MVT Zn-Pb mineralization in the Behabad district. To address the foregoing issue, analyses of the spatial distribution of mineral deposits comprising fry and fractal techniques and analysis of the spatial association of mineral deposits with geological features using distance distribution analysis were applied to assess the regional-scale processes that could have operated in the distribution of MVT Zn-Pb deposits in the district. The obtained results based on these analytical techniques show the main trends of the occurrences are NW-SE and NE-SW, which are parallel or subparallel to the major northwest and northeast trending faults, supporting the idea that these particular faults could have acted as the main conduits for transport of mineral-bearing fluids. The results of these analyses also suggest that Permian-Triassic brittle carbonate sedimentary rocks have served as the lithological controls on MVT mineralization in the Behabad district as they are spatially and temporally associated with mineralization.

Bismuth-silver mineralization in the Sergozerskoe gold occurrence

Directory of Open Access Journals (Sweden)

Kalinin A. A.

2017-03-01

Full Text Available Bismuth-silver mineralization attendant to gold mineralization in the Sergozerskoe gold occurrence has been studied in detail. Bi-Ag mineralization is connected with diorite porphyry dykes, which cut volcanic-sedimentary Lopian complexes of the Strel'ninsky greenstone belt – hornblendite and actinolite-chlorite amphibolites, biotite and bi-micaceous gneisses. Distribution of Bi-Ag mineralization similar to gold mineralization is controlled by 80 m thick zone of silicification. Bi minerals are found in brecciated diorite porphyry. Bismuth-silver mineralization includes native metals (bismuth, electrum, silver, tellurides (hedleyite, hessite, selenides (ikunolite, sulfides and sulfosalts of Bi and Ag (matildite, lillianite, eckerite, jalpaite, prustite, acanthite, a few undiagnosed minerals. All Bi and Ag minerals associate with galena. Composition of mineralization evolved from early to late stages of development, depending on intensity of rock alteration. The earliest Bi-Ag minerals were native bismuth and hedleyite formed dissemination in galena, and electrum with 30-45 mass.% Au. Later native bismuth was partly substituted by silver and bismuth sulfosalts and bismuth sulfides. The latest minerals were low-temperature silver sulfides eckerite, jalpaite, and acanthite, which were noted only in the most intensively altered rocks. As soon as the process of formation of Bi-Ag mineralization is the same as formation of gold, findings of bismuth-silver mineralization can serve as a positive exploration sign for gold in the region.

Clean thermal decomposition of tertiary-alkyl metal thiolates to metal sulfides: environmentally-benign, non-polar inks for solution-processed chalcopyrite solar cells

Science.gov (United States)

Heo, Jungwoo; Kim, Gi-Hwan; Jeong, Jaeki; Yoon, Yung Jin; Seo, Jung Hwa; Walker, Bright; Kim, Jin Young

2016-11-01

We report the preparation of Cu2S, In2S3, CuInS2 and Cu(In,Ga)S2 semiconducting films via the spin coating and annealing of soluble tertiary-alkyl thiolate complexes. The thiolate compounds are readily prepared via the reaction of metal bases and tertiary-alkyl thiols. The thiolate complexes are soluble in common organic solvents and can be solution processed by spin coating to yield thin films. Upon thermal annealing in the range of 200-400 °C, the tertiary-alkyl thiolates decompose cleanly to yield volatile dialkyl sulfides and metal sulfide films which are free of organic residue. Analysis of the reaction byproducts strongly suggests that the decomposition proceeds via an SN1 mechanism. The composition of the films can be controlled by adjusting the amount of each metal thiolate used in the precursor solution yielding bandgaps in the range of 1.2 to 3.3 eV. The films form functioning p-n junctions when deposited in contact with CdS films prepared by the same method. Functioning solar cells are observed when such p-n junctions are prepared on transparent conducting substrates and finished by depositing electrodes with appropriate work functions. This method enables the fabrication of metal chalcogenide films on a large scale via a simple and chemically clear process.

21 CFR 888.3520 - Knee joint femorotibial metal/polymer non-constrained cemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metal/polymer non... § 888.3520 Knee joint femorotibial metal/polymer non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer non-constrained cemented prosthesis is a device intended to...

Disposal of radioactive waste from mining and processing of mineral sands

International Nuclear Information System (INIS)

Hartley, B.M.

1993-01-01

All mineral sands products contain the naturally radioactive elements uranium and thorium and their daughters. The activity levels in the different minerals can vary widely and in the un mined state are frequently widely dispersed and add to the natural background radiation levels. Following mining, the minerals are concentrated to a stage where radiation levels can present an occupational hazard and disposal of waste can result in radiation doses in excess of the public limit. Chemical processing can release radioactive daughters, particularly radium, leading to the possibility of dispersal and resulting in widespread exposure of the public. The activity concentration in the waste can vary widely and different disposal options appropriate to the level of activity in the waste are needed. Disposal methods can range from dilution and dispersal of the material into the mine site, for untreated mine tailings, to off site disposal in custom built and engineered waste disposal facilities, for waste with high radionuclide content. The range of options for disposal of radioactive waste from mineral sands mining and processing is examined and the principles for deciding on the appropriate disposal option are discussed. The range of activities of waste from different downstream processing paths are identified and a simplified method of identifying potential waste disposal paths is suggested. 15 refs., 4 tabs

Cleavage of hydrogen by activation at a single non-metal centre - towards new hydrogen storage materials.

Science.gov (United States)

Grabowski, Sławomir J

2015-05-28

Molecular surfaces of non-metal species are often characterized by both positive and negative regions of electrostatic potential (EP) at a non-metal centre. This centre may activate molecular hydrogen which further leads to the addition reaction. The positive EP regions at the non-metal centres correspond to σ-holes; the latter sites are enhanced by electronegative substituents. This is why the following simple moieties; PFH2, SFH, AsFH2, SeFH, BrF3, PF(CH3)2 and AsF(CH3)2, were chosen here to analyze the H2 activation and its subsequent splitting at the P, As, S, Se and Br centres. Also the reverse H-H bond reforming process is analyzed. MP2/aug-cc-pVTZ calculations were performed for systems corresponding to different stages of these processes. The sulphur centre in the SFH moiety is analyzed in detail since the potential barrier height for the addition reaction for this species is the lowest of the moieties analyzed here. The results of calculations show that the SFH + H2 → SFH3 reaction in the gas phase is endothermic but it is exothermic in polar solvents.

The effect of non-equilibrium metal cooling on the interstellar medium

Science.gov (United States)

Capelo, Pedro R.; Bovino, Stefano; Lupi, Alessandro; Schleicher, Dominik R. G.; Grassi, Tommaso

2018-04-01

By using a novel interface between the modern smoothed particle hydrodynamics code GASOLINE2 and the chemistry package KROME, we follow the hydrodynamical and chemical evolution of an isolated galaxy. In order to assess the relevance of different physical parameters and prescriptions, we constructed a suite of 10 simulations, in which we vary the chemical network (primordial and metal species), how metal cooling is modelled (non-equilibrium versus equilibrium; optically thin versus thick approximation), the initial gas metallicity (from 10 to 100 per cent solar), and how molecular hydrogen forms on dust. This is the first work in which metal injection from supernovae, turbulent metal diffusion, and a metal network with non-equilibrium metal cooling are self-consistently included in a galaxy simulation. We find that properly modelling the chemical evolution of several metal species and the corresponding non-equilibrium metal cooling has important effects on the thermodynamics of the gas, the chemical abundances, and the appearance of the galaxy: the gas is typically warmer, has a larger molecular-gas mass fraction, and has a smoother disc. We also conclude that, at relatively high metallicity, the choice of molecular-hydrogen formation rates on dust is not crucial. Moreover, we confirm that a higher initial metallicity produces a colder gas and a larger fraction of molecular gas, with the low-metallicity simulation best matching the observed molecular Kennicutt-Schmidt relation. Finally, our simulations agree quite well with observations that link star formation rate to metal emission lines.

Canadian minerals yearbook : 2004 review and outlook

International Nuclear Information System (INIS)

2004-01-01

The main focus of the CMY publication is the non-fuel mineral industry, together with uranium, although all mineral fuels are normally included when the total value of Canada's mineral production is reported. The Yearbook includes chapters devoted to each major mineral commodity produced in Canada: aluminum, coal, copper, diamonds, gold, iron ore, magnesium, nickel, potash, salt, silica, and uranium. The subject matter spans all stages of mineral industry activity from geoscience and exploration, through mining and processing, to markets and use. Although domestic issues receive the greatest attention in each chapter, international developments may also be reviewed because of the global nature of the mineral industry and the significant impact that such developments could have on the Canadian industry

Toenail as Non-invasive Biomarker in Metal Toxicity Measurement of Welding Fumes Exposure - A Review

Science.gov (United States)

Bakri, S. F. Z.; Hariri, A.; Ma'arop, N. F.; Hussin, N. S. A. W.

2017-01-01

Workers are exposed to a variety of heavy metal pollutants that are released into the environment as a consequence of workplace activities. This chemical pollutants are incorporated into the human by varies of routes entry and can then be stored and distributed in different tissues, consequently have a potential to lead an adverse health effects and/or diseases. As to minimize the impact, a control measures should be taken to avoid these effects and human biological marker is a very effective tool in the assessment of occupational exposure and potential related risk as the results is normally accurate and reproducible. Toenail is the ideal matrix for most common heavy metals due to its reliability and practicality compared to other biological samples as well as it is a non-invasive and this appears as a huge advantage of toenail as a biomarker. This paper reviews studies that measure the heavy metals concentration in toenail as non-invasive matrix which later may adapt in the investigation of metal fume emitted from welding process. The development of new methodology and modern analytical techniques has allowed the use of toenail as non-invasive approach. The presence of a heavy metal in this matrix reflects an exposure but the correlations between heavy metal levels in the toenail must be established to ensure that these levels are related to the total body burden. These findings suggest that further studies on interactions of these heavy metals in metal fumes utilizing toenail biomarker endpoints are highly warranted especially among welders.

The use of tomographic techniques in the mineral processing Industry. A review

International Nuclear Information System (INIS)

Witika, L.K.; Jere, E.H.

2002-01-01

Process tomographic techniques may be used to analyse the internal state of most of the multiphase process engineering systems such as material segregation in a reactor multiphase flow in pipes and the spatial resolution of mineral grains in multiphase particles. These techniques include radiation computed tomography (X-ray or ray), electrical methods(capacitance, impedance and inductive tomography) positron emission tomography,optical tomography, microwave tomography, acoustic tomographical methods and many more. Many potential applications exist for process tomographic instrumentation for quantitative analysis and fault-detection purposes. Amongst these, electrical methods are widely used for those mineral processes deserving particular attention such as dense-medium separation, hydro cyclones, flotation cells and columns, gas-liquid absorbers, solvent extraction and other liquid-liquid processes, filtration and other solid-liquid processes, grinding mills (both dry and wet, conveyors and hoppers). Development in on-line measurement instrumentation now allow direct observation of the behaviour of fluids inside mineral separation equipment. This offers the possibility to acquire process data to enable models to be devised, to verify theoretical computational fluid dynamics predictions and control of various unit processes. In this review, the most important tomographic sensing methods are reviewed. Examples of the implementation of some electrical methods are illustrated. (authors)

ANALYSIS OF NONMAGNETIC METAL INDUCTION HEATING PROCESSES BY FLAT-TYPE CIRCULAR SOLENOIDAL FIELD

Directory of Open Access Journals (Sweden)

Yu. Batygin

2016-12-01

Full Text Available The article analyzes the electromagnetic processes in the system of induction heating with estimating the main characteristics of heating the non-magnetic sheet metal. The analytical expressions for numerical estimates of the induced current in terms of the phase of the excitation signal are presented. The dependence for the heating temperature of the considered circular sheet metal area for the time corresponding to the interval phase has been determined.

Agronomic potential of mineral concentrate from processed manure as fertiliser

NARCIS (Netherlands)

Velthof, G.L.; Hoeksma, P.; Schröder, J.J.; Middelkoop, van J.C.; Geel, van W.C.A.; Ehlert, P.A.I.; Holshof, G.; Klop, G.; Lesschen, J.P.

2012-01-01

Processing of manure intends to increase the use efficiency of nutrients. A concentrated solution of nitrogen (N) and potassium (K) (‘mineral concentrate’) is one of the possible products resulting from manure processing. A study is carried out in the Netherlands to determine the agronomic and

A novel property of DNA - as a bioflotation reagent in mineral processing.

Science.gov (United States)

Vasanthakumar, Balasubramanian; Ravishankar, Honnavar; Subramanian, Sankaran

2012-01-01

Environmental concerns regarding the use of certain chemicals in the froth flotation of minerals have led investigators to explore biological entities as potential substitutes for the reagents in vogue. Despite the fact that several microorganisms have been used for the separation of a variety of mineral systems, a detailed characterization of the biochemical molecules involved therein has not been reported so far. In this investigation, the selective flotation of sphalerite from a sphalerite-galena mineral mixture has been achieved using the cellular components of Bacillus species. The key constituent primarily responsible for the flotation of sphalerite has been identified as DNA, which functions as a bio-collector. Furthermore, using reconstitution studies, the obligatory need for the presence of non-DNA components as bio-depressants for galena has been demonstrated. A probable model involving these entities in the selective flotation of sphalerite from the mineral mixture has been discussed.

A novel property of DNA - as a bioflotation reagent in mineral processing.

Directory of Open Access Journals (Sweden)

Balasubramanian Vasanthakumar

Full Text Available Environmental concerns regarding the use of certain chemicals in the froth flotation of minerals have led investigators to explore biological entities as potential substitutes for the reagents in vogue. Despite the fact that several microorganisms have been used for the separation of a variety of mineral systems, a detailed characterization of the biochemical molecules involved therein has not been reported so far. In this investigation, the selective flotation of sphalerite from a sphalerite-galena mineral mixture has been achieved using the cellular components of Bacillus species. The key constituent primarily responsible for the flotation of sphalerite has been identified as DNA, which functions as a bio-collector. Furthermore, using reconstitution studies, the obligatory need for the presence of non-DNA components as bio-depressants for galena has been demonstrated. A probable model involving these entities in the selective flotation of sphalerite from the mineral mixture has been discussed.

INDUCTION HEATING OF NON-MAGNETIC SHEET METALS IN THE FIELD OF A FLAT CIRCULAR MULTITURN SOLENOID

Directory of Open Access Journals (Sweden)

Y. Batygin

2016-06-01

Full Text Available The theoretical analysis of electromagnetic processes in the system for induction heating presented by a flat circular multiturn solenoid positioned above a plane of thin sheet non-magnetic metal has been conducted. The calculated dependences for the current induced in a metal sheet blank and ratio of transformation determined have been obtained. The maximal value of the transformation ratio with regard to spreading the eddy-currents over the whole area of the sheet metal has been determined.

Blackberry wines mineral and heavy metal content determination after dry ashing: multivariate data analysis as a tool for fruit wine quality control.

Science.gov (United States)

Amidžić Klarić, Daniela; Klarić, Ilija; Mornar, Ana; Velić, Darko; Velić, Natalija

2015-08-01

This study brings out the data on the content of 21 mineral and heavy metal in 15 blackberry wines made of conventionally and organically grown blackberries. The objective of this study was to classify the blackberry wine samples based on their mineral composition and the applied cultivation method of the starting raw material by using chemometric analysis. The metal content of Croatian blackberry wine samples was determined by AAS after dry ashing. The comparison between an organic and conventional group of investigated blackberry wines showed statistically significant difference in concentrations of Si and Li, where the organic group contained higher concentrations of these compounds. According to multivariate data analysis, the model based on the original metal content data set finally included seven original variables (K, Fe, Mn, Cu, Ba, Cd and Cr) and gave a satisfactory separation of two applied cultivation methods of the starting raw material.

Highly Active Non-PGM Catalysts Prepared from Metal Organic Frameworks

Directory of Open Access Journals (Sweden)

Heather M. Barkholtz

2015-06-01

Full Text Available Finding inexpensive alternatives to platinum group metals (PGMs is essential for reducing the cost of proton exchange membrane fuel cells (PEMFCs. Numerous materials have been investigated as potential replacements of Pt, of which the transition metal and nitrogen-doped carbon composites (TM/Nx/C prepared from iron doped zeolitic imidazolate frameworks (ZIFs are among the most active ones in catalyzing the oxygen reduction reaction based on recent studies. In this report, we demonstrate that the catalytic activity of ZIF-based TM/Nx/C composites can be substantially improved through optimization of synthesis and post-treatment processing conditions. Ultimately, oxygen reduction reaction (ORR electrocatalytic activity must be demonstrated in membrane-electrode assemblies (MEAs of fuel cells. The process of preparing MEAs using ZIF-based non-PGM electrocatalysts involves many additional factors which may influence the overall catalytic activity at the fuel cell level. Evaluation of parameters such as catalyst loading and perfluorosulfonic acid ionomer to catalyst ratio were optimized. Our overall efforts to optimize both the catalyst and MEA construction process have yielded impressive ORR activity when tested in a fuel cell system.

Understanding Non-Equilibrium Charge Transport and Rectification at Chromophore/Metal Interfaces

Science.gov (United States)

Darancet, Pierre

Understanding non-equilibrium charge and energy transport across nanoscale interfaces is central to developing an intuitive picture of fundamental processes in solar energy conversion applications. In this talk, I will discuss our theoretical studies of finite-bias transport at organic/metal interfaces. First, I will show how the finite-bias electronic structure of such systems can be quantitatively described using density functional theory in conjunction with simple models of non-local correlations and bias-induced Stark effects.. Using these methods, I will discuss the conditions of emergence of highly non-linear current-voltage characteristics in bilayers made of prototypical organic materials, and their implications in the context of hole- and electron-blocking layers in organic photovoltaic. In particular, I will show how the use of strongly-hybridized, fullerene-coated metallic surfaces as electrodes is a viable route to maximizing the diodic behavior and electrical functionality of molecular components. The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (Argonne). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357.

The problem of the involvement of the off-balance reserves of the metallic ores into the production process

Directory of Open Access Journals (Sweden)

V. I. Golik

2017-12-01

Full Text Available The underground mining of the ore deposits by means of the intensive methods of the traditional technologies is characterized by the loss of the reserves, which are off-balance for the technologies applied. The experience, which was accumulated by the state-of-the-art enterprises before the economic reforms and the crisis indicates, that it is possible to decrease the loss of metals. This can be assumed by means of involving the off-balance reserves into the production process with the metal lixiviation during closed work. The purpose of the present-day research is the substantiation of the technical possibility and economic reasonability of the lixiviation of metals from the off-balance reserves and poorly balance ores. The correct estimation of the perspectives of those combined technology is still one of the purposes. It is a matter of fact that combining traditional technologies of the underground mining with new ones concerned with the creation of the effective lixiviation of metals from ores can be carried out with the two-stage processing. It happens when the excavation of some amount of the balance reserves creates the compensational space for crushing off-balance reserves. Involving off-balance ores into the production process solves a set of the mining production problems. For example, the fullness of mineral resources usage, the strengthening of the resource base, the reduction of load of the environment and the security of works. The involvement of the off-balance reserves into the development in the course of the revaluation of the resources and in the technological facilities of the development in the context of the growth of the scale of production reduces the production price to the competitive level. The field of application of these results is in the mining enterprises which extract solid metal-containing ores by means of the underground mining. These ores are mostly of the nonferrous, rare and precious metals, which are easily

Synthesis and Catalytic Applications of Non-Metal Doped Mesoporous Titania

Directory of Open Access Journals (Sweden)

Syed Z. Islam

2017-03-01

Full Text Available Mesoporous titania (mp-TiO2 has drawn tremendous attention for a diverse set of applications due to its high surface area, interfacial structure, and tunable combination of pore size, pore orientation, wall thickness, and pore connectivity. Its pore structure facilitates rapid diffusion of reactants and charge carriers to the photocatalytically active interface of TiO2. However, because the large band gap of TiO2 limits its ability to utilize visible light, non-metal doping has been extensively studied to tune the energy levels of TiO2. While first-principles calculations support the efficacy of this approach, it is challenging to efficiently introduce active non-metal dopants into the lattice of TiO2. This review surveys recent advances in the preparation of mp-TiO2 and their doping with non-metal atoms. Different doping strategies and dopant sources are discussed. Further, co-doping with combinations of non-metal dopants are discussed as strategies to reduce the band gap, improve photogenerated charge separation, and enhance visible light absorption. The improvements resulting from each doping strategy are discussed in light of potential changes in mesoporous architecture, dopant composition and chemical state, extent of band gap reduction, and improvement in photocatalytic activities. Finally, potential applications of non-metal-doped mp-TiO2 are explored in water splitting, CO2 reduction, and environmental remediation with visible light.

Development of Ceramic Coating on Metal Substrate using Industrial Waste and Ore Minerals

Science.gov (United States)

Bhuyan, S. K.; Thiyagarajan, T. K.; Mishra, S. C.

2017-02-01

The technological advancement in modern era has a boon for enlightening human life; but also is a bane to produce a huge amount of (industrial) wastes, which is of great concern for utilization and not to create environmental threats viz. polution etc. In the present piece of research work, attempts have been made to utilize fly ash (wastes of thermal power plants) and along with alumina bearing ore i.e. bauxite, for developing plasma spray ceramic coatings on metals. Fly ash and with 10 and 20% bauxite addition is used to deposit plasma spray coatings on a metal substrate. The surface morphology of the coatings deposited at different power levels of plasma spraying investigated through SEM and EDS analysis. The coating thickness is measured. The porosity levels of the coatings are evaluated. The coating hardness isalso measured. This piece of research work will be beneficial for future development and use of industrial waste and ore minerals for high-valued applications.

Enhanced metal recovery through oxidation in liquid and/or supercritical carbon dioxide

KAUST Repository

Blanco, Mario

2017-08-24

Process for enhanced metal recovery from, for example, metal-containing feedstock using liquid and/or supercritical fluid carbon dioxide and a source of oxidation. The oxidation agent can be free of complexing agent. The metal-containing feedstock can be a mineral such as a refractory mineral. The mineral can be an ore with high sulfide content or an ore rich in carbonaceous material. Waste can also be used as the metal-containing feedstock. The metal-containing feedstock can be used which is not subjected to ultrafine grinding. Relatively low temperatures and pressures can be used. The metal-containing feedstock can be fed into the reactor at a temperature below the critical temperature of the carbon dioxide, and an exotherm from the oxidation reaction can provide the supercritical temperature. The oxidant can be added to the reactor at a rate to maintain isothermal conditions in the reactor. Minimal amounts of water can be used as an extractive medium.

A Multi-Scale Study on the Role of Trace Metals on Physiological and Pathological Mineralization

Science.gov (United States)

Rammelkamp, Derek

The work in this thesis provides mulit-scale contributions towards understanding the effects of trace metals on the pathological mineralization process relating to both the development of healthy bone tissue, the diseased state of osteoporosis, and microcalcifications which develop in breast cancers. A protein level study was performed on ECM protein fibronectin, which plays a role in cell adhesion. The protein studies showed zinc interactions with fibronectin and its fragment, anastellin, to influence protein structure. Zinc is also shown to decrease cell migration in vitro, which may be influenced by changes in fibronectin ECM structure. The effects of osteoporosis on micronutrient composition in vivo were examined using the technique of x-ray fluorescence (XRF) in an ovariectomized rat model. Compared to healthy bone, subtle difference are observed in zinc and iron in osteoporotic rat bones, showing micronutrients may play an important role in healthy bone regulation. Effects of micronutrient zinc was used to inhibit microcalcification formation in breast cancers. Microcalcifications have been linked malignancy of breast cancers, but the process of microcalcification formation has yet to be well understood. In this work, exogenous zinc is used to inhibit microcalcification formation, and metastatic potential in both a 2D and 3D spheroid environment. A novel in vitro self-assembled three dimensional multi-cellular tumor spheroid (MCTS) model for the study of breast cancer microcalcifications was developed for this experiment. A MCTS model for studying breast cancer microcalcifications has potential to be used in drug discovery, or for basic research applications studying mechanisms of microcalcification formation, which are still not fully understood. Taken together this study uses a multi-scale approach to gain a better understanding of micronutrients involved in pathological mineralization.

Improved process control through real-time measurement of mineral content

Energy Technology Data Exchange (ETDEWEB)

Turler, Daniel; Karaca, Murat; Davis, William B.; Giauque, Robert D.; Hopkins, Deborah

2001-11-02

In a highly collaborative research and development project with mining and university partners, sensors and data-analysis tools are being developed for rock-mass characterization and real-time measurement of mineral content. Determining mineralogy prior to mucking in an open-pit mine is important for routing the material to the appropriate processing stream. A possible alternative to lab assay of dust and cuttings obtained from drill holes is continuous on-line sampling and real-time x-ray fluorescence (XRF) spectroscopy. Results presented demonstrate that statistical analyses combined with XRF data can be employed to identify minerals and, possibly, different rock types. The objective is to create a detailed three-dimensional mineralogical map in real time that would improve downstream process efficiency.

Laser Processing Technology using Metal Powders

Energy Technology Data Exchange (ETDEWEB)

Jang, Jeong-Hwan; Moon, Young-Hoon [Pusan National University, Busan (Korea, Republic of)

2012-03-15

The purpose of this paper is to review the state of laser processing technology using metal powders. In recent years, a series of research and development efforts have been undertaken worldwide to develop laser processing technologies to fabricate metal-based parts. Layered manufacturing by the laser melting process is gaining ground for use in manufacturing rapid prototypes (RP), tools (RT) and functional end products. Selective laser sintering / melting (SLS/SLM) is one of the most rapidly growing rapid prototyping techniques. This is mainly due to the processes's suitability for almost any materials, including polymers, metals, ceramics and many types of composites. The interaction between the laser beam and the powder material used in the laser melting process is one of the dominant phenomena defining feasibility and quality. In the case of SLS, the powder is not fully melted during laser scanning, therefore the SLS-processed parts are not fully dense and have relatively low strength. To overcome this disadvantage, SLM and laser cladding (LC) processes have been used to enable full melting of the powder. Further studies on the laser processing technology will be continued due to the many potential applications that the technology offers.

Theoretical Analysis of Unit Friction Force Working on the Metal Contact Surface with the Roll Change during Feedstock with Non-Uniform Temperature Distribution Rolling Process

Directory of Open Access Journals (Sweden)

Sygut P.

2016-06-01

Full Text Available The paper presents the results of theoretical studies influence of non-uniform temperature distribution along the feedstock length to the unit friction force working on the metal contact surface with the roll change during the round bars 70 mm in diameter continuous rolling process. This value is one of the major factors affecting the grooves wear during the rolling process. The studies were carried out based on the actual engineering data for 160 × 160 mm square cross-section feedstock of steel S355J0. Numerical modelling of the rolling process was performed using Forge2008®, a finite-element based computer program.

The diesel exhaust in miners study: II. Exposure monitoring surveys and development of exposure groups.

NARCIS (Netherlands)

Coble, J.B.; Stewart, P.A.; Vermeulen, R.; Yereb, D.; Stanevich, R.; Blair, A.; Silverman, D.T.; Attfield, M.

2010-01-01

Air monitoring surveys were conducted between 1998 and 2001 at seven non-metal mining facilities to assess exposure to respirable elemental carbon (REC), a component of diesel exhaust (DE), for an epidemiologic study of miners exposed to DE. Personal exposure measurements were taken on workers in a

Beach sand mineral industries in India and challenges of value addition

International Nuclear Information System (INIS)

Patra, R.N.

2016-01-01

Beach sand minerals (BSM) are a suite of seven minerals that often occur together in various proportions in the beach sands of coastal India. They are also called heavy minerals as they have densities in the range 3.2 gms/cc to 5.2 gms/cc, which are higher than the sand. Ilmenite, leucoxene and rutile are oxide minerals of titanium metal. Zircon is silicate of zirconium where as silimanite is silicate of aluminum. The titanium, zirconium and thorium bearing minerals are atomic minerals under the atomic energy act 1962 and need no objection from the Department of Atomic Energy (DAE) for their mining. Further authorization is necessary from DAE to handle and process monazite as it contains thorium, as it is a prescribed substance under the notification issued under the atomic energy act. Radioactive nature of monazite also mandates obtaining permission from Atomic Energy Regulatory Board (AERB) with a view to ensure regulatory compliance with radiological safety. Monazite is processed to produce rare earths, trisodium phosphate (TSP) and thorium compounds.Thorium values are stockpiled in engineered trenches for use in nuclear power program of the country where as rare earths are used for manufacture of high power permanent magnets, energy efficient optical phosphors, metal alloys for battery to store electricity and hydrogen, as additives to glass for imparting special optical properties and myriads of applications in defence and strategic sectors. Rare earths of late have assumed importance as high power rare earths based permanent magnets are used in manufacture of wind mills, MRI machines, magnetic levitated bearings etc, having minimal impact on green house gas generation and use in renewable energy sector. The presentation brings out the limitation of value added product industries in India, the efforts taken by Indian Rare Earths Ltd. (IREL) in developing value added products in the face of technology denial regime and hostile market dynamics. The road map for

Environmental Risk of Metal Mining Contaminated River Bank Sediment at Redox-Transitional Zones

Directory of Open Access Journals (Sweden)

Sarah F. L. Lynch

2014-01-01

Full Text Available Diffuse metal pollution from mining impacted sediment is widely recognised as a potential source of contamination to river systems and may significantly hinder the achievement of European Union Water Framework Directive objectives. Redox-transitional zones that form along metal contaminated river banks as a result of flood and drought cycles could cause biogeochemical changes that alter the behaviour of polyvalent metals iron and manganese and anions such as sulphur. Trace metals are often partitioned with iron, manganese and sulphur minerals in mining-contaminated sediment, therefore the dissolution and precipitation of these minerals may influence the mobility of potentially toxic trace metals. Research indicates that freshly precipitated metal oxides and sulphides may be more “reactive” (more adsorbent and prone to dissolution when conditions change than older crystalline forms. Fluctuations at the oxic-anoxic interface brought about through changes in the frequency and duration of flood and drought episodes may therefore influence the reactivity of secondary minerals that form in the sediment and the flux of dissolved trace metal release. UK climate change models predict longer dry periods for some regions, interspersed with higher magnitude flood events. If we are to fully comprehend the future environmental risk these climate change events pose to mining impacted river systems it is recommended that research efforts focus on identifying the primary controls on trace metal release at the oxic-anoxic interface for flood and drought cycles of different duration and frequency. This paper critically reviews the literature regarding biogeochemical processes that occur at different temporal scales during oxic, reducing and dry periods and focuses on how iron and sulphur based minerals may alter in form and reactivity and influence the mobility of trace metal contaminants. It is clear that changes in redox potential can alter the composition

Impacts of Nickel Nanoparticles on Mineral Carbonation

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Marius Bodor

2014-01-01

Full Text Available This work presents experimental results regarding the use of pure nickel nanoparticles (NiNP as a mineral carbonation additive. The aim was to confirm if the catalytic effect of NiNP, which has been reported to increase the dissolution of CO2 and the dissociation of carbonic acid in water, is capable of accelerating mineral carbonation processes. The impacts of NiNP on the CO2 mineralization by four alkaline materials (pure CaO and MgO, and AOD and CC steelmaking slags, on the product mineralogy, on the particle size distribution, and on the morphology of resulting materials were investigated. NiNP-containing solution was found to reach more acidic pH values upon CO2 bubbling, confirming a higher quantity of bicarbonate ions. This effect resulted in acceleration of mineral carbonation in the first fifteen minutes of reaction time when NiNP was present. After this initial stage, however, no benefit of NiNP addition was seen, resulting in very similar carbonation extents after one hour of reaction time. It was also found that increasing solids content decreased the benefit of NiNP, even in the early stages. These results suggest that NiNP has little contribution to mineral carbonation processes when the dissolution of alkaline earth metals is rate limiting.

Fatal Cobalt Toxicity after a Non-Metal-on-Metal Total Hip Arthroplasty

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Rinne M. Peters

2017-01-01

Full Text Available This case illustrates the potential for systemic cobalt toxicity in non-metal-on-metal bearings and its potentially devastating consequences. We present a 71-year-old male with grinding sensations in his right hip following ceramic-on-ceramic total hip arthroplasty (THA. After diagnosing a fractured ceramic liner, the hip prosthesis was revised into a metal-on-polyethylene bearing. At one year postoperatively, X-rays and MARS-MRI showed a fixed reversed hybrid THA, with periarticular densities, flattening of the femoral head component, and a pattern of periarticular metal wear debris and pseudotumor formation. Before revision could take place, the patient was admitted with the clinical picture of systemic cobalt toxicity, supported by excessively high serum cobalt and chromium levels, and ultimately died. At autopsy dilated cardiomyopathy as cause of death was hypothesized. A third body wear reaction between ceramic remnants and the metal femoral head very likely led to excessive metal wear, which contributed systemic cobalt toxicity leading to neurotoxicity and heart failure. This case emphasizes that fractured ceramic-on-ceramic bearings should be revised to ceramic-on-ceramic or ceramic-on-polyethylene bearings, but not to metal-on-polyethylene bearings. We aim to increase awareness among orthopedic surgeons for clinical clues for systemic cobalt intoxication, even when there is no metal-on-metal bearing surface.

Were mercury emission factors for Chinese non-ferrous metal smelters overestimated? Evidence from onsite measurements in six smelters

International Nuclear Information System (INIS)

Zhang Lei; Wang Shuxiao; Wu Qingru; Meng Yang; Yang Hai; Wang Fengyang; Hao Jiming

2012-01-01

Non-ferrous metal smelting takes up a large proportion of the anthropogenic mercury emission inventory in China. Zinc, lead and copper smelting are three leading sources. Onsite measurements of mercury emissions were conducted for six smelters. The mercury emission factors were 0.09–2.98 g Hg/t metal produced. Acid plants with the double-conversion double-absorption process had mercury removal efficiency of over 99%. In the flue gas after acid plants, 45–88% was oxidized mercury which can be easily scavenged in the flue gas scrubber. 70–97% of the mercury was removed from the flue gas to the waste water and 1–17% to the sulfuric acid product. Totally 0.3–13.5% of the mercury in the metal concentrate was emitted to the atmosphere. Therefore, acid plants in non-ferrous metal smelters have significant co-benefit on mercury removal, and the mercury emission factors from Chinese non-ferrous metal smelters were probably overestimated in previous studies. - Highlights: ► Acid plants in smelters provide significant co-benefits for mercury removal (over 99%). ► Most of the mercury in metal concentrates for smelting ended up in waste water. ► Previously published emission factors for Chinese metal smelters were probably overestimated. - Acid plants in smelters have high mercury removal efficiency, and thus mercury emission factors for Chinese non-ferrous metal smelters were probably overestimated.

Flotation process of lead-, copper-, uranium-, and rare earth minerals

International Nuclear Information System (INIS)

Broman, P.G.; Kihlstedt, P.G.; Du Rietz, C.

1977-01-01

This invention relates to a flotation process of oxide or sulfide ores containing lead-, copper-, uranium-, and rare earth minerals applicating a new collector. Flotation is in the presence of a tertiary amine

Using microorganisms to recover metals

International Nuclear Information System (INIS)

Jeffers, T.H.

1991-01-01

Biological processes have been used for thousands of years to make cheese, wine, and beer. During the past few hundred years these processes have been employed to process sewage. Increasingly, microbes are being used to clean up a wide variety of toxic chemical wastes that have been dumped into the environment. Scientists are currently examining the possible use of microbes to detoxify naturally occurring toxic selenium-bearing water at the Kesterson Wildlife Refuge. The mining and minerals industries also use biological processes to remove impurities from ores, cut processing costs, and treat some metallic ores that previously were too difficult or too expensive to process by traditional methods. In this article, the term 'mining industry' applies to the extraction of ore whereas the term 'minerals industry' applies to processing the ore. Applications of biotechnology in the mining and minerals industries are expected to increase. The paper discusses the use of microbial leaching in the copper, uranium, gold, and manganese mining industries; treatments of mine wastes; the treatment of cyanide solution, and research into bioleaching, biosorption, and genetic engineering

The use of neutron radiography and microdensitometry in the study of instrumental effectiveness on dental tissue in the process of mineralization

International Nuclear Information System (INIS)

Vulcain, J.M.; Tamisier, J.; Espie, J.H.; Masse, R.; Laporte, A.

1983-01-01

In this study, neutron-radiography is used as a non-destructive method of exposing the peripheral part of the root canal which, in the course of endodontic treatment, is to be removed by root therapy instruments. Samples are treated with an agent of contrast with high screen power for neutrons: gadolinium which is used in the form of a citrate solution, it slowly diffuses through non-mineralized structures and settles like the other rare earths on the interface of mineralized tissues and of those in the process of mineralization, in this case, dentin and predentin. This mechanism is on occasion controlled by the richness of proteoglycans in this tissue. Once the samples are saturated, a neutron-radiographic image is made, then analyzed by microdensitometry so as to obtain a quantitative parameter. After instrumentation of the samples, a new neutron-radiographic image, and a new microdensitometric analysis are made. The results thus obtained make it possible to quantify the effectiveness of the various instruments available for endodontic treatments. (Auth.)

Mass transport in non crystalline metallic alloys

International Nuclear Information System (INIS)

Limoge, Y.

1986-08-01

In order to improve our understanding of mass transport in non crystalline metallic alloys we have developed indirect studies of diffusion based on electron irradiation and hydrostatic pressure effects upon crystallization. In a first part we present the models of crystallization which are used, then we give the experimental results. The main point is the first experimental measurement of the activation volume for diffusion in a metallic glass: the value of which is roughly one atomic volume. We show also recent quantitative results concerning radiation enhanced diffusion in metallic glasses (FeNi) 8 (PB) 2 and Ni 6 Nb 4 . In a last part we discuss the atomic model needed to explain our results

Using of Mineral Recourses for Water Purification

International Nuclear Information System (INIS)

Tumanova, I.V.; Nazarenko, O.B.; Anna, Yu.

2009-01-01

Pollution of surface waters results in necessity of underground waters using for drinking. Underground waters are characterized by the high quantity of heavy metals salts. This led to development of methods reducing the concentration of the metal salts in water. Wide spread occurrence, cheapness and high sorption properties of nature minerals allow to consider them as perspective sorbents for different impurities extraction, including dissoluble compounds of heavy metals. Reachable purification efficiency with mineral resources use for the moment satisfies sanitary indexes and standards presenting to portable water in Russia. In given material there are presented the results of research of artificial sorbent and certain minerals sorption characteristics, which are typical for West Siberia. For purification quality improvement from Fe and Mn ions there are suggested to use the method of boiling bed.

Significance, mechanisms and environmental implications of microbial bio-mineralization

International Nuclear Information System (INIS)

Benzerara, K.; Miot, J.; Morin, G.; Ona-Nguema, G.; Skouri-Panet, F.; Ferard, C.

2011-01-01

Microorganisms can mediate the formation of minerals by a process called bio-mineralization. This process offers an efficient way to sequester inorganic pollutants within relatively stable solid phases. Here we review some of the main mechanisms involved in the mediation of mineral precipitation by microorganisms. This includes supersaturation caused by metabolic activity, the triggering of nucleation by production of more or less specific organic molecules, and the impact of mineral growth. While these processes have been widely studied in the laboratory, assessment of their importance in the environment is more difficult. We illustrate this difficulty using a case study on an As-contaminated acid mine drainage located in the South of France (Carnoules, Gard). In particular, we explore the potential relationships that might exist between microbial diversity and mineral precipitation. The present review, far from being exhaustive, highlights some recent advances in the field of bio-mineralogy and provides non-specialists an introduction to some of the main approaches and some questions that remain unanswered. (authors)

Intermediate sulfidation type base metal mineralization at Aliabad-Khanchy, Tarom-Hashtjin metallogenic belt, NW Iran

Science.gov (United States)

Kouhestani, Hossein; Mokhtari, Mir Ali Asghar; Chang, Zhaoshan; Johnson, Craig A.

2018-01-01

The Aliabad-Khanchy epithermal base metal deposit is located in the Tarom-Hashtjin metallogenic belt (THMB) of northwest Iran. The mineralization occurs as Cu-bearing brecciated quartz veins hosted by Eocene volcanic and volcaniclastic rocks of the Karaj Formation. Ore formation can be divided into five stages, with most ore minerals, such as pyrite and chalcopyrite being formed in the early stages. The main wall-rock alteration is silicification, and chlorite, argillic and propylitic alteration. Microthermometric measurements of fluid inclusion assemblages show that the ore-forming fluids have eutectic temperatures between −30 and −52 °C, trapping temperatures of 150–290 °C, and salinities of 6.6–12.4 wt% NaCl equiv. These data demonstrate that the ore-forming fluids were medium- to high-temperature, medium- to low-salinity, and low-density H2O–NaCl–CaCl2 fluids. Calculated δ18O values indicate that ore-forming hydrothermal fluids had δ18Owater ranging from +3.6‰ to +0.8‰, confirming that the ore–fluid system evolved from dominantly magmatic to dominantly meteoric. The calculated 34SH2S values range from −8.1‰ to −5.0‰, consistent with derivation of the sulfur from either magma or possibly from local volcanic wall-rock. Combined, the fluid inclusion and stable isotope data indicate that the Aliabad-Khanchy deposit formed from magmatic-hydrothermal fluids. After rising to a depth of between 790 and 500 m, the fluid boiled and subsequent hydraulic fracturing may have led to inflow and/or mixing of early magmatic fluids with circulating groundwater causing deposition of base metals due to dilution and/or cooling. The Aliabad-Khanchy deposit is interpreted as an intermediate-sulfidation style of epithermal mineralization. Our data suggest that the mineralization at Aliabad-Khanchy and other epithermal deposits of the THMB formed by hydrothermal activity related to shallow late Eocene magmatism. The altered Eocene volcanic and

Design, fabrication, and application of a directional thermal processing system for controlled devitrification of metallic glasses

Science.gov (United States)

Meyer, Megan Anne Lamb

The potential of using metallic glass as a pathway to obtaining novel morphologies and metastable phases has been garnering attention since their discovery. Several rapid solidification techniques; such as gas atomization, melt spinning, laser melting, and splat quenching produce amorphous alloys. A directional thermal processing system (DTPS) was designed, fabricated and characterized for the use of zone processing or gradient-zone processing of materials. Melt-spun CuZr metallic glass alloy was subjected to the DTPS and the relaxation and crystallization responses of the metallic glass were characterized. A range of processing parameters were developed and analyzed that would allow for devitrification to occur. The relaxation and crystallization responses were compared with traditional heat treatment methods of metallic glasses. The new processing method accessed equilibrium and non-equilibrium phases of the alloy and the structures were found to be controllable and sensitive to processing conditions. Crystallized fraction, crystallization onset temperature, and structural relaxation were controlled through adjusting the processing conditions, such as the hot zone temperature and sample velocity. Reaction rates computed from isothermal (TTT) transformation data were not found to be reliable, suggesting that the reaction kinetics are not additive. This new processing method allows for future studying of the thermal history effects of metallic glasses.

Computer Simulation of the Formation of Non-Metallic Precipitates During a Continuous Casting of Steel

Directory of Open Access Journals (Sweden)

Kalisz D.

2016-03-01

Full Text Available The authors own computer software, based on the Ueshima mathematical model with taking into account the back diffusion, determined from the Wołczyński equation, was developed for simulation calculations. The applied calculation procedure allowed to determine the chemical composition of the non-metallic phase in steel deoxidised by means of Mn, Si and Al, at the given cooling rate. The calculation results were confirmed by the analysis of samples taken from the determined areas of the cast ingot. This indicates that the developed computer software can be applied for designing the steel casting process of the strictly determined chemical composition and for obtaining the required non-metallic precipitates.

Bioprocessing of coal - 10 - an application of microbial flotation to mineral processing

Energy Technology Data Exchange (ETDEWEB)

Nagaoka, T. [and others] [CRIEPI, Abiko-shi (Japan). Abiko Research Lab.

1996-09-01

Microbial flotation for coal desulfurization is being developed. Pyrite in coal is removed by bacterial adhesion by changing the surface property of pyrite. The bacterial adhesion of Thiobacillus ferrooxidans to sulfide minerals (pyrite, galena, molybdenite, chalcocite and millerite), and pyrite removal from the mixture of these sulfide minerals by microbial flotation was investigated. To compare the adhesion of T. ferrooxidans to pyrite with that to the other four minerals mentioned, the surface areas of the minerals, where the bacterium could adhere, was measured. It was observed that the roughness on the mineral surfaces was much smaller than the size of the bacterial cells. Hence, it was suggested that the roughness did not affect the bacterial adhesion to mineral surfaces. Bacterial adhesion to pyrite was compared with that to the other minerals. The amount of adhering bacterium was estimated on the basis of the adherable surface area measured with microscopic method. The amount of adhering cells to pyrite was 421.6 x 10{sup 8} cells/cm{sup 2}. On the other hand, the amounts of adhering cells to the minerals, except for pyrite were in a range of 77.1 to 160.8 x 10{sup 8} cells/cm{sup 2}. The bacterium adheres more to pyrite than to the other minerals, and only adheres to pyrite even if the pyrite is mixed with other minerals. Hence, T. ferrooxidans could adhere selectively to pyrite. Pyrite removal from the mineral mixtures was investigated with microbial flotation. Pyrite removal was in a range of 83.7% to 95.1% and mineral recovery was 72.9% to 100%. The grade of recovered minerals was in a range of 79.2 to 86.0% and that of rejected pyrite was in a range of 78.7 to 90.0%. These results suggest that microbial flotation can be a novel technology for mineral processing.

Coating a polystyrene well-plate surface with synthetic hematite, goethite and aluminium hydroxide for cell mineral adhesion studies in a controlled environment

International Nuclear Information System (INIS)

Pouran, Hamid M.; Banwart, Steve A.; Romero-Gonzalez, Maria

2014-01-01

Highlights: • Hematite, goethite and aluminium hydroxide were synthesized and characterize. • Polystyrene cell culture well plates were coated with the synthetic metal oxides. • The coated well plates proven to be completely identical to the synthetic minerals. • The coating method is compatible with what occurs in aquifers with metal oxides. • This method provides a key experimental part for cell mineral adhesion studies. - Abstract: Iron and aluminium oxides are available in many climatic regions and play a vital role in many environmental processes, including the interactions of microorganisms in contaminated soils and groundwater with their ambient environment. Indigenous microorganisms in contaminated environments often have the ability to degrade or transform those contaminants, a concept that supports an in situ remediation approach and uses natural microbial populations in order to bio-remediate polluted sites. These metal oxides have a relatively high pH-dependent surface charge, which makes them good candidates for studying mineral–bacterial adhesion. Given the importance of understanding the reactions that occur at metal oxide and bacterial cell interfaces and to investigate this phenomenon further under well-characterized conditions, some of the most common iron and aluminium oxides; hematite, goethite and aluminium hydroxide, were synthesized and characterized and a coating method was developed to coat polystyrene well-plates as a surface exposable to bacterial adhesion with these minerals (non-treated polystyrene-12 well-plates which are used for cell cultures). The coating process was designed in a way that resembles naturally coated surfaces in aquifers. Hematite, Fe 2 O 3 , was synthesized from acidic FeCl 3 solution, while goethite, FeOOH, and aluminium hydroxide, Al(OH) 3 , were prepared from an alkaline solution of Fe(NO 3 ) 3 and Al(NO 3 ) 3 . They were further characterized using X-ray diffraction (XRD), Fourier transform infrared

Waste removal in pyrochemical fuel processing for the Integral Fast Reactor

International Nuclear Information System (INIS)

Ackerman, J.P.; Johnson, T.R.; Laidler, J.J.

1994-01-01

Electrorefining in a molten salt electrolyte is used in the Integral Fast Reactor fuel cycle to recover actinides from spent fuel. Processes that are being developed for removing the waste constituents from the electrorefiner and incorporating them into the waste forms are described in this paper. During processing, halogen, chalcogen, alkali, alkaline earth, and rare earth fission products build up in the molten salt as metal halides and anions, and fuel cladding hulls and noble metal fission products remain as metals of various particle sizes. Essentially all transuranic actinides are collected as metals on cathodes, and are converted to new metal fuel. After processing, fission products and other waste are removed to a metal and a mineral waste form. The metal waste form contains the cladding hulls, noble metal fission products, and (optionally) most rare earths in a copper or stainless steel matrix. The mineral waste form contains fission products that have been removed from the salt into a zeolite or zeolite-derived matrix

Resource nationalism in Indonesia—Effects of the 2014 mineral export ban

Science.gov (United States)

Lederer, Graham W.

2016-09-27

Resource nationalism encompasses a broad range of political and economic actions taken by Governments to regulate the extraction of natural resources within their borders. Policies such as increased tariffs or export restrictions can have far-reaching economic effects on international trade. As the Governments of several developing countries consider enacting nationalistic policies, an examination of the 2014 mineral export ban in Indonesia provides an instructive example of the possible impacts of resource nationalism. Significant changes in the production and trade of unprocessed (that is, ores and concentrates) and processed (that is, refined metal) aluminum, copper, and nickel before and after the export ban form the basis of this study.The U.S. Geological Survey (USGS) National Minerals Information Center (NMIC) tracks production and trade of mineral commodities between producer and consumer countries. Materials flow studies clarify the effects of an export ban on different mineral commodities by assessing changes in production, processing capacity, and trade. Using extensive data collection and monitoring procedures, the USGS NMIC investigated the effects of resource nationalism on the flow of mineral commodities from Indonesia to the global economy.

Application of Hydroforming Process in Sheet Metal Formation

OpenAIRE

GRIZELJ, Branko; CUMIN, Josip; ERGIĆ, Todor

2009-01-01

This article deals with the theory and application of a hydroforming process. Nowadays automobile manufacturers use high strength sheet metal plates. This high strength steel sheet metal plates are strain hardened in the process of metal forming. With the use of high strength steel, cars are made lightweight, which is intended for low fuel consumption because of high energy prices. Some examples of application of a hydroforming process are simulated with FEM.

Precious metal recovery from waste printed circuit boards using cyanide and non-cyanide lixiviants--A review.

Science.gov (United States)

Akcil, Ata; Erust, Ceren; Gahan, Chandra Sekhar; Ozgun, Mehmet; Sahin, Merve; Tuncuk, Aysenur

2015-11-01

Waste generated by the electrical and electronic devices is huge concern worldwide. With decreasing life cycle of most electronic devices and unavailability of the suitable recycling technologies it is expected to have huge electronic and electrical wastes to be generated in the coming years. The environmental threats caused by the disposal and incineration of electronic waste starting from the atmosphere to the aquatic and terrestrial living system have raised high alerts and concerns on the gases produced (dioxins, furans, polybrominated organic pollutants, and polycyclic aromatic hydrocarbons) by thermal treatments and can cause serious health problems if the flue gas cleaning systems are not developed and implemented. Apart from that there can be also dissolution of heavy metals released to the ground water from the landfill sites. As all these electronic and electrical waste do posses richness in the metal values it would be worth recovering the metal content and protect the environmental from the pollution. Cyanide leaching has been a successful technology worldwide for the recovery of precious metals (especially Au and Ag) from ores/concentrates/waste materials. Nevertheless, cyanide is always preferred over others because of its potential to deliver high recovery with a cheaper cost. Cyanidation process also increases the additional work of effluent treatment prior to disposal. Several non-cyanide leaching processes have been developed considering toxic nature and handling problems of cyanide with non-toxic lixiviants such as thiourea, thiosulphate, aqua regia and iodine. Therefore, several recycling technologies have been developed using cyanide or non-cyanide leaching methods to recover precious and valuable metals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Electromagnetic detection and infrared visualization techniques for non-metallic inclusions in molten aluminum

International Nuclear Information System (INIS)

Fei Ming; Ludwig, Reinhold; Shankar, Sumanth; Apelian, Diran

2002-01-01

The role of detecting non-metallic and weakly conducting inclusions in hot melts during the manufacturing process is of major importance. However, the key impediment to assessing melt cleanliness is the quantification of the level of inclusions. In this paper, we present the theory and practice in using a magnetic force-based detection system capable of monitoring small inclusions of micron-size dimensions. The idea is to force the non-conducting inclusions to a detection location (the free melt surface) by electromagnetic Archimedes forces. Further, an infrared (IR) imaging system can then be applied to detect their thermal signature. Finally, a novel image-processing algorithm is used to analyze the inclusion level on the measurement surface

Non-traditional Stable Isotope Systematics of Seafloor Hydrothermal Systems

Science.gov (United States)

Rouxel, O. J.

2009-05-01

Seafloor hydrothermal activity at mid-ocean ridges is one of the fundamental processes controlling the chemistry of the oceans and the altered oceanic crust. Past studies have demonstrated the complexity and diversity of seafloor hydrothermal systems and have highlighted the importance of subsurface environments in controlling the composition of hydrothermal fluids and mineralization types. Traditionally, the behavior of metals in seafloor hydrothermal systems have been investigated by integrating results from laboratory studies, theoretical models, mineralogy and fluid and mineral chemistry. Isotope ratios of various metals and metalloids, such as Fe, Cu, Zn, Se, Cd and Sb have recently provided new approaches for the study of seafloor hydrothermal systems. Despite these initial investigations, the cause of the isotopic variability of these elements remains poorly constrained. We have little understanding of the isotope variations between vent types (black or white smokers) as well as the influence of source rock composition (basalt, felsic or ultrabasic rocks) and alteration types. Here, I will review and present new results of metal isotope systematics of seafloor hydrothermal systems, in particular: (1) determination of empirical isotope fractionation factors for Zn, Fe and Cu-isotopes through isotopic analysis of mono-mineralic sulfide grains lining the internal chimney wall in contact with hydrothermal fluid; (2) comparison of Fe- and Cu-isotope signatures of vent fluids from mid- oceanic and back-arc hydrothermal fields, spanning wide ranges of pH, temperature, metal concentrations and contributions of magmatic fluids enriched in SO2. Ultimately, the use of complementary non-traditional stable isotope systems may help identify and constrain the complex interactions between fluids,minerals, and organisms in seafloor hydrothermal systems.

Value added phytoremediation of metal stressed soils using phosphate solubilizing microbial consortium.

Science.gov (United States)

Gupta, Pratishtha; Kumar, Vipin

2017-01-01

The presence of heavy metals in the soil is a matter of growing concern due to their toxic and non-biodegradable nature. Lack of effectiveness of various conventional methods due to economic and technical constraints resulted in the search for an eco-friendly and cost-effective biological techniques for heavy metal removal from the environment. Until now, phytoremediation has emerged as an innovative technique to address the problem. However, the efficiency of phytoremediation process is hindered under the high metal concentration conditions. Hence, phosphate solubilizing microbes (PSM) assisted phytoremediation technique is gaining more insight as it can reduce the contamination load even under elevated metal stressed conditions. These microbes convert heavy metals into soluble and bioavailable forms, which consequently facilitate phytoremediation. Several studies have reported that the use of microbial consortium for remediation is considered more effective as compared to single strain pure culture. Therefore, this review paper focuses on the current trends in research related to PSM mediated uptake of heavy metal by plants. The efficiency of PSM consortia in enhancing the phytoremediation process has also been reviewed. Moreover, the role of phosphatase enzymes in the mineralization of organic forms of phosphate in soil is further discussed. Biosurfactant mediated bioremediation of metal polluted soils is a matter of extensive research nowadays. Hence, the recent advancement of using biosurfactants in enhanced phytoremediation of metal stressed soils is also described.

Significance of bioleaching method in dissolution of iron and in the quality improvement of non-metallics

Directory of Open Access Journals (Sweden)

Iveta Štyriaková

2006-12-01

Full Text Available Simple laboratory bioleaching experiments for the iron removal with heterotrophic bacteria on natural raw materials were conducted to explore a simple cyclic operation for a potential use at the industrial scale. Heterotrophic bacteria of Bacillus spp. growing in the presence of feldspar raw materials are able to dissolve iron. Anaerobic conditions Quickly formed by bacteria enable a simple manipulation with the sample solution. Insoluble Fe(III in the feldspars sample could be enzymatically dissolved as Fe3+ and also reduced to soluble Fe2+ by silicate bacteria of Bacillus spp. This metal was efficiently removed from the feldspars sample as documented by a Fe2O3 decrease (from 0.29 % to 0.12 % after bioleaching in the conical flask and by a Fe2O3 decrease (from 0.29 % to 0.19 % after bioleaching in the percolate column. Bioleaching of Fe was more effective in the conical flask. Iron-bearing minerals can be easily removed by magnetic separation, but ultra fine iron particles are difficult to treat by conventional mineral processing methods. Thus bioleaching is an attractive alternative for effective removal of iron minerals. The removal of iron with the whiteness increase should give a product, which is fit for industrial ceramic applications.

Kinetics and Mechanism of Metal Retention/Release in Geochemical Processes in Soil - Final Report

Energy Technology Data Exchange (ETDEWEB)

Taylor, Robert W.

2000-12-29

Effective, remediation of soils contaminated with heavy metals requires a better understanding of the mechanisms by which the metals are retained/released in soils over a long period of time. Studies on reaction of Cr(VI) with iron-rich clays indicated that structural iron (II) in these surfaces is capable of reducing chromate to chromium (III). We found that iron (II) either found naturally or produced by treatment of clay with sodium dithionite, effectively reduced Cr (VI) to Cr (III). Thus, in situ remediation of chromium combines reduction of Cr (VI) to Cr (III) and immobilization of chromium on mineral surfaces. During this study, lead sorption on a kaolin surface was found to be a rapid and a pH dependant process in which lead sorption significantly increased with the amount of phosphate on the clay surface. This study verifies that methylmercury cation remains intact when it binds to humic acids, forming a monodentate complex with some sub-population of humic thiol ligands .

Optimal fabrication processes for unidirectional metal-matrix composites: A computational simulation

Science.gov (United States)

Saravanos, D. A.; Murthy, P. L. N.; Morel, M.

1990-01-01

A method is proposed for optimizing the fabrication process of unidirectional metal matrix composites. The temperature and pressure histories are optimized such that the residual microstresses of the composite at the end of the fabrication process are minimized and the material integrity throughout the process is ensured. The response of the composite during the fabrication is simulated based on a nonlinear micromechanics theory. The optimal fabrication problem is formulated and solved with non-linear programming. Application cases regarding the optimization of the fabrication cool-down phases of unidirectional ultra-high modulus graphite/copper and silicon carbide/titanium composites are presented.

Noble Metal/Ceramic Composites in Flame Processes

DEFF Research Database (Denmark)

Schultz, Heiko; Madler, Lutz; Strobel, Reto

conditions influence the resulting noble metal particles size in those systems [1]. For every specific application the particle size and the metal/metal oxide interaction affect the performance of these nano-composite materials [2]. Recently, aerosol processes have been successfully used to produce platinum...

A Novel Property of DNA – As a Bioflotation Reagent in Mineral Processing

Science.gov (United States)

Vasanthakumar, Balasubramanian; Ravishankar, Honnavar; Subramanian, Sankaran

2012-01-01

Environmental concerns regarding the use of certain chemicals in the froth flotation of minerals have led investigators to explore biological entities as potential substitutes for the reagents in vogue. Despite the fact that several microorganisms have been used for the separation of a variety of mineral systems, a detailed characterization of the biochemical molecules involved therein has not been reported so far. In this investigation, the selective flotation of sphalerite from a sphalerite-galena mineral mixture has been achieved using the cellular components of Bacillus species. The key constituent primarily responsible for the flotation of sphalerite has been identified as DNA, which functions as a bio-collector. Furthermore, using reconstitution studies, the obligatory need for the presence of non-DNA components as bio-depressants for galena has been demonstrated. A probable model involving these entities in the selective flotation of sphalerite from the mineral mixture has been discussed. PMID:22768298

Fumarolic minerals

DEFF Research Database (Denmark)

Balic Zunic, Tonci; Garavelli, Anna; Jakobsson, Sveinn Peter

2016-01-01

The fumarolic mineralogy of the Icelandic active volcanoes, the Tyrrhenian volcanic belt (Italy) and the Aegean active arc (Greece) is investigated, and literature data surveyed in order to define the characteristics of the European fumarolic systems. They show broad diversity of mineral...... associations, with Vesuvius and Vulcano being also among the world localities richest in mineral species. Volcanic systems, which show recession over a longer period, show fumarolic development from the hightemperature alkaline halide/sulphate, calcic sulphate or sulphidic parageneses, synchronous...... with or immediately following the eruptions, through mediumtemperature ammonium minerals, metal chlorides, or fluoride associations to the late low-temperature paragenesis dominated by sulphur, gypsum, alunogen, and other hydrous sulphates. The situation can be different in the systems that are not recessing but show...

Description of Latvian Metal Production and Processing Enterprises' Air Emissions

OpenAIRE

Pubule, J; Zahare, D; Blumberga, D

2010-01-01

The metal production and processing sector in Latvia has acquired a stable position in the national economy. Smelting of ferrous and nonferrous metals, production of metalware, galvanisation, etc. are developed in Latvia. The metal production and processing sector has an impact on air quality due to polluting substances which are released in the air from metal treatment processes. Therefore it is necessary to determine the total volume of emissions produced by the metal production and process...

Solvent extraction of gold using ionic liquid based process

Science.gov (United States)

Makertihartha, I. G. B. N.; Zunita, Megawati; Rizki, Z.; Dharmawijaya, P. T.

2017-01-01

In decades, many research and mineral processing industries are using solvent extraction technology for metal ions separation. Solvent extraction technique has been used for the purification of precious metals such as Au and Pd, and base metals such as Cu, Zn and Cd. This process uses organic compounds as solvent. Organic solvents have some undesired properties i.e. toxic, volatile, excessive used, flammable, difficult to recycle, low reusability, low Au recovery, together with the problems related to the disposal of spent extractants and diluents, even the costs associated with these processes are relatively expensive. Therefore, a lot of research have boosted into the development of safe and environmentally friendly process for Au separation. Ionic liquids (ILs) are the potential alternative for gold extraction because they possess several desirable properties, such as a the ability to expanse temperature process up to 300°C, good solvent properties for a wide range of metal ions, high selectivity, low vapor pressures, stability up to 200°C, easy preparation, environmentally friendly (commonly called as "green solvent"), and relatively low cost. This review paper is focused in investigate of some ILs that have the potentials as solvent in extraction of Au from mineral/metal alloy at various conditions (pH, temperature, and pressure). Performances of ILs extraction of Au are studied in depth, i.e. structural relationship of ILs with capability to separate Au from metal ions aggregate. Optimal extraction conditon in order to gain high percent of Au in mineral processing is also investigated.

Mineralogy of accessory and rare minerals associated with chromite deposits in the Khoy area

International Nuclear Information System (INIS)

Emamalipour, A.

2008-01-01

The chromite deposits in the Khoy area have lenticular, tubular and vein-like shapes which are found in serpenlinized hurzburgite. Chromite and serpentine are major minerals and hematite and magnetite are minor phases in the chromitic ores .Furthermore, Fe, Ni, Cu, Co, Zn, Ru, Os, Ir, La, Ce, Gd and S elements are found as base metal sulfides, sulfides of platinum group elements, metal oxides, native elements, natural alloys and solid inclusions in chromite grains and or in serpentinic ground mass. These minerals have very fine grain sizes and recognitions of them by ore microscopic method was limited, so the investigations were continued by EMPA. The majority of these minerals have secondary origin and are related with serpentinization. processes and only a few of them have primary origin. Among sulfide minerals bravoite, pyrotite, milerite, linaite and pyrite have secondary origin, whereas pentlandite has primary one. Chalcopyrite has been formed in two generations, as both primary and secondary origins. Among primary platinum group elements minerals lourite ((Ru, Os, Ir)S 2 ) is considerable, which was found as a solid inclusion in the chromite grain and has primary origin. Native metals and natural alloys such as nickel, copper, iron and josephinite (Ni 3 Fe) have been formed in micro fractures of chromite grains filled by serpentine. A few rare earth element-rich compositions were found in micro fractures also and have secondary origin

Tritium processing using metal hydrides

International Nuclear Information System (INIS)

Mallett, M.W.

1986-01-01

E.I. duPont de Nemours and Company is commissioned by the US Department of Energy to operate the Savannah River Plant and Laboratory. The primary purpose of the plant is to produce radioactive materials for national defense. In keeping with current technology, new processes for the production of tritium are being developed. Three main objectives of this new technology are to ease the processing of, ease the storage of, and to reduce the operating costs of the tritium production facility. Research has indicated that the use of metal hydrides offers a viable solution towards satisfying these objectives. The Hydrogen and Fuels Technology Division has the responsibility to conduct research in support of the tritium production process. Metal hydride technology and its use in the storage and transportation of hydrogen will be reviewed

Methanogens predominate in natural corrosion protective layers on metal sheet piles.

NARCIS (Netherlands)

Kip, Nardy; Jansen, S.; Leite, M.F.A.; De Hollander, M.; Afanasyev, M.; Kuramae, E.E.; van Veen, J.A.

2017-01-01

Microorganisms are able to cause, but also to inhibit or protect against corrosion. Corrosion inhibition by microbial processes may be due to the formation of mineral deposition layers on metal objects. Such deposition layers have been found in archaeological studies on ancient metal objects, buried

Evaluation of Mineral Deposits Along the Little Wind River, Riverton, WY, Processing Site

Energy Technology Data Exchange (ETDEWEB)

Campbell, Sam [Navarro Research and Engineering, Oak Ridge, TN (United States); Dam, Wiliam [US Department of Energy, Washington, DC (United States). Office of Legacy Management

2014-12-01

In 2012, the U.S.Department of Energy (DOE) began reassessing the former Riverton, Wyoming, Processing Site area for potential contaminant sources impacting groundwater. A flood in 2010 along the Little Wind River resulted in increases in groundwater contamination (DOE 2013).This investigation is a small part of continued efforts by DOE and other stakeholders to update human health and ecological risk assessments, to make a comprehensive examination of all exposure pathways to ensure that the site remains protective through established institutional controls. During field inspections at the Riverton Site in 2013, a white evaporitic mineral deposit was identified along the bank of the Little Wind River within the discharge zone of the groundwater contamination plume. In December 2013, Savannah River National Laboratory (SRNL) personnel collected a sample for analysis by X-ray fluorescence (Figure 1 shows the type of material sampled). The sample had a uranium concentration of approximately 64 to 73 parts per million. Although the uranium in this mineral deposit is within the expected range for evaporatic minerals in the western United States (SRNL 2014), DOE determined that additional assessment of the mineral deposit was warranted. In response to the initial collection and analysis of a sample of the mineral deposit, DOE developed a work plan (Work Plan to Sample Mineral Deposits Along the Little Wind River, Riverton, Wyoming, Processing Site [DOE 2014]) to further define the extent of these mineral deposits and the concentration of the associated contaminants (Appendix A). The work plan addressed field reconnaissance, mapping, sampling, and the assessment of risk associated with the mineral deposits adjacent to the Little Wind River.

Combination of magnetic parameters and heavy metals to discriminate soil-contamination sources in Yinchuan--a typical oasis city of Northwestern China.

Science.gov (United States)

Xia, Dunsheng; Wang, Bo; Yu, Ye; Jia, Jia; Nie, Yan; Wang, Xin; Xu, Shujing

2014-07-01

Various industrial processes and vehicular traffic result in harmful emissions containing both magnetic minerals and heavy metals. In this study, we investigated the levels of magnetic and heavy metal contamination of topsoils from Yinchuan city in northwestern China. The results demonstrate that magnetic mineral assemblages in the topsoil are dominated by pseudo-single domain (PSD) and multi-domain (MD) magnetite. The concentrations of anthropogenic heavy metals (Cr, Cu, Pb and Zn) and the magnetic properties of χlf, SIRM, χARM, and 'SOFT' and 'HARD' remanence are significantly correlated, suggesting that the magnetic minerals and heavy metals have common sources. Combined use of principal components and fuzzy cluster analysis of the magnetic and chemical data set indicates that the magnetic and geochemical properties of the particulates emitted from different sources vary significantly. Samples from university campus and residential areas are mainly affected by crustal material, with low concentrations of magnetic minerals and heavy metals, while industrial pollution sources are characterized by high concentrations of coarse magnetite and Cr, Cu, Pb and Zn. Traffic pollution is characterized by Pb and Zn, and magnetite. Magnetic measurements of soils are capable of differentiating sources of magnetic minerals and heavy metals from industrial processes, vehicle fleets and soil parent material. Copyright © 2014 Elsevier B.V. All rights reserved.

A Novel Approach To Mineral Carbonation: Enhancing Carbonation While Avoiding Mineral Pretreatment Process Cost

Energy Technology Data Exchange (ETDEWEB)

Michael J. McKelvy; Andrew V. G. Chizmeshya; Kyle Squires; Ray W. Carpenter; Hamdallah Bearat

2006-06-21

Known fossil fuel reserves, especially coal, can support global energy demands for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Unlike other CO{sub 2} sequestration candidate technologies that propose long-term storage, mineral sequestration provides permanent disposal by forming geologically stable mineral carbonates. Carbonation of the widely occurring mineral olivine (e.g., forsterite, Mg{sub 2}SiO{sub 4}) is a large-scale sequestration process candidate for regional implementation, which converts CO{sub 2} into the environmentally benign mineral magnesite (MgCO{sub 3}). The primary goal is cost-competitive process development. As the process is exothermic, it inherently offers low-cost potential. Enhancing carbonation reactivity is key to economic viability. Recent studies at the U.S. DOE Albany Research Center have established that aqueous-solution carbonation using supercritical CO{sub 2} is a promising process; even without olivine activation, 30-50% carbonation has been achieved in an hour. Mechanical activation (e.g., attrition) has accelerated the carbonation process to an industrial timescale (i.e., near completion in less than an hour), at reduced pressure and temperature. However, the activation cost is too high to be economical and lower cost pretreatment options are needed. Herein, we report our second year progress in exploring a novel approach that offers the potential to substantially enhance carbonation reactivity while bypassing pretreatment activation. As our second year progress is intimately related to our earlier work, the report is presented in that context to provide better overall understanding of the progress made. We have discovered that robust silica-rich passivating layers form on the olivine surface during carbonation. As carbonation proceeds, these passivating layers thicken, fracture and eventually exfoliate, exposing fresh olivine surfaces during rapidly

Method for nanomodulation of metallic thin films following the replica-antireplica process based on porous alumina membranes

Energy Technology Data Exchange (ETDEWEB)

Palma, J.L. [Departamento de Ciencias Básicas, Facultad de Ingeniería, Universidad Central de Chile, Santa Isabel 1186, 8330601 Santiago (Chile); Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago (Chile); Denardin, J.C.; Escrig, J. [Departamento de Física, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 9170124 Santiago (Chile); Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago (Chile)

2017-03-15

In this paper we have introduced a method for modulation of metallic thin films by sputtering of metals on anodized aluminum templates. Using a high deposition rate during deposition of the non-magnetic metal on the Al pattern, we have separated the two metallic surfaces and, thus, imprinted a pattern of nanohills on a non-magnetic metallic film, such as Au, Ag or Cu. The morphology of the nanostructured metallic films was determined by scanning electron microscopy. Thus, we have confirmed that the ordering degree of the Al template remained after the replication process. Additionally, and as an example of use of these films, we have prepared Supermalloy thin films deposited by sputtering onto these nanostructured non-magnetic metals. The room temperature magnetic behavior of these thin films is also studied. Interestingly, we have found that when the external magnetic field is applied out of plane of the substrate, the coercivity increases linearly as we increase the radius of the nanohills. These soft magnetic films can open new opportunities for magnetic field sensor applications. - Highlights: • A very soft magnetic film is investigated on ordered nanohills. • It is possible to imprint a metallic pattern directly from the etched aluminum foil. • These nanopatterned substrates add an additional degree of freedom. • A method for modulation of metallic thin films.

Mass fractionation processes of transition metal isotopes

Science.gov (United States)

Zhu, X. K.; Guo, Y.; Williams, R. J. P.; O'Nions, R. K.; Matthews, A.; Belshaw, N. S.; Canters, G. W.; de Waal, E. C.; Weser, U.; Burgess, B. K.; Salvato, B.

2002-06-01

Recent advances in mass spectrometry make it possible to utilise isotope variations of transition metals to address some important issues in solar system and biological sciences. Realisation of the potential offered by these new isotope systems however requires an adequate understanding of the factors controlling their isotope fractionation. Here we show the results of a broadly based study on copper and iron isotope fractionation during various inorganic and biological processes. These results demonstrate that: (1) naturally occurring inorganic processes can fractionate Fe isotope to a detectable level even at temperature ˜1000°C, which challenges the previous view that Fe isotope variations in natural system are unique biosignatures; (2) multiple-step equilibrium processes at low temperatures may cause large mass fractionation of transition metal isotopes even when the fractionation per single step is small; (3) oxidation-reduction is an importation controlling factor of isotope fractionation of transition metal elements with multiple valences, which opens a wide range of applications of these new isotope systems, ranging from metal-silicate fractionation in the solar system to uptake pathways of these elements in biological systems; (4) organisms incorporate lighter isotopes of transition metals preferentially, and transition metal isotope fractionation occurs stepwise along their pathways within biological systems during their uptake.

Composition suitable as collection agent in ore flotation process and preparation of said composition

International Nuclear Information System (INIS)

Bresson, C.R.; Parlman, R.M.

1984-01-01

A composition and process are provided for the recovery of the values of zinc, molybdenum, copper, lead, ion (pyrite), and iron-containing small amounts of gold or uranium, or both, from ores comprising these mineral sulfides. The aqueous composition is the impure form of an alkali metal alkyl trithiocarbonate compound. The process comprises employing said aqueous composition as a collection agent for the above minerals in an ore recovery process. A process for the separation of zinc values from lead values from an ore comprising both is provided by employing an alkali metal alkyl trithiocarbonate compound as a collection agent for zinc. In addition, both a composition and process are provided for the recovery of the values of iron, copper, and lead from ores comprising these values. The composition consists essentially of a dispersant and an impure form of an alkali metal alkyl trithiocarbonate compound. The process comprises employing this composition as a collection agent for the above minerals in an ore recovery process

Multi Blending Technology (MBT): mineral processing method for increasing added value of marginal reserve

Science.gov (United States)

Agustinus, E. T. S.

2018-02-01

Indonesia's position on the path of ring of fire makes it rich in mineral resources. Nevertheless, in the past, the exploitation of Indonesian mineral resources was uncontrolled resulting in environmental degradation and marginal reserves. Exploitation of excessive mineral resources is very detrimental to the state. Reflecting on the occasion, the management and utilization of Indonesia's mineral resources need to be good in mining practice. The problem is how to utilize the mineral reserve resources effectively and efficiently. Utilization of marginal reserves requires new technologies and processing methods because the old processing methods are inadequate. This paper gives a result of Multi Blending Technology (MBT) Method. The underlying concept is not to do the extraction or refinement but processing through the formulation of raw materials by adding an additive and produce a new material called functional materials. Application of this method becomes important to be summarized into a scientific paper in a book form, so that the information can spread across multiple print media and become focused on and optimized. This book is expected to be used as a reference for stakeholder providing added value to environmentally marginal reserves in Indonesia. The conclusions are that Multi Blending Technology (MBT) Method can be used as a strategy to increase added values effectively and efficiently to marginal reserve minerals and that Multi Blending Technology (MBT) method has been applied to forsterite, Atapulgite Synthesis, Zeoceramic, GEM, MPMO, SMAC and Geomaterial.

Minerals yearbook: The mineral industry of Brazil. 1988 international review

International Nuclear Information System (INIS)

Ensminger, H.R.

1988-01-01

Brazil's gross domestic product (GDP) grew only slightly in 1988 to $277 billion at current prices. The growth rate was the smallest registered since 1983, when the rate was minus 2.8%. The economy's performance was strongly influenced by a 2% to 3% decrease in industrial production and civil construction. The mineral industry, however, countered the downward trend in the industrial sector and grew a modest 1.4%. Topics discussed in the report include the following: Government policies and programs; Production; Trade; Commodity review--Metals (Aluminum, Aluminia, and Bauxite, Columbium, Copper, Gold, Iron and Steel, Manganese, Tin, Titanium); Industrial Minerals (Gem stones, Phosphate rock, Quartz); Mineral fuels (Coal, Natural gas, Petroleum, Nuclear power); Nonmineral energy sources (Alcohol, Hydroelectric)

Improvement in grade of minerals using simultaneous Bio-oxidation of invisible gold concentrate and deep-sea manganese crust

Science.gov (United States)

Myung, EunJi; Cho, Kang Hee; Kim, Hyun Soo; Park, Cheon Young

2016-04-01

Many sulfides of metal such as galena, sphalerite, chalcopyrite, and pyrite, are semiconductors. When two kinds of such minerals contact each other in an electrolyte, a galvanic couple, where the mineral of lower rest potential as anode, and that of higher rest potential as cathode forms. Manganese dioxide is also a semiconductor with much higher rest potential than all sulfides mentioned above, so that a galvanic couple in which both the minerals would dissolve simultaneously can form, when it contacts with any of the sulfides. The aim of this study was to investigate the improvement in grade of minerals using the simultaneous bio-oxidation of deep-sea manganese crust and invisible gold concentrate. The samples(deep-sea manganese crust and invisible gold concentrate) were characterized by chemical and XRD analysis. The primary components of the invisible gold concentrate was pyrite and quartz and the deep-sea manganese crust was amorphous material, as detected using XRD. The result of chemical analysis showed that Au, Ag, Te contents in the invisible gold concentrate 130.2, 954.1 and 1,043.6 mg/kg, respectively. and that Mn, Ni, Co contents in the deep-sea manganese crust 19,501.5, 151.9, 400.4 mg/kg, respectively. In order to increase the bacteria's tolerance of heavy metals, the bacteria using bio-oxidation experiments were repeatedly subcultured in an Cu adaptation-medium containing of 382.98 mg/l for 20 periods of 21 days. The improvement in grade of samples of in present adapted bacteria condition was greater than another conditions(control and in present non-adapted bacteria). The Au-Ag-Te contents in the invisible gold concentrate was enhanced in the order of physical oxidation, simultaneous/non-adaptive bio-oxidation, adaptive/bio-oxidation, simultaneous/adaptive bio-oxidation. If the bacteria is adapted to heavy metal ions and an optimization of conditions is found in future bio-oxidation-leaching processes. Acknowledgment : "This research was supported

ATOMIC-LEVEL IMAGING OF CO2 DISPOSAL AS A CARBONATE MINERAL: OPTIMIZING REACTION PROCESS DESIGN; A

International Nuclear Information System (INIS)

M.J. McKelvy; R. Sharma; A.V.G. Chizmeshya; H. Bearat; R.W. Carpenter

2001-01-01

Fossil fuels, especially coal, can support the energy demands of the world for centuries to come, if the environmental problems associated with CO(sub 2) emissions can be overcome. Permanent and safe methods for CO(sub 2) capture and disposal/storage need to be developed. Mineralization of stationary-source CO(sub 2) emissions as carbonates can provide such safe capture and long-term sequestration. Mg-rich lamellar-hydroxide based minerals (e.g., brucite and serpentine) offer a class of widely available, low-cost materials, with intriguing mineral carbonation potential. Carbonation of such materials inherently involves dehydroxylation, which can disrupt the material down to the atomic level. As such, controlled dehydroxylation, before and/or during carbonation, may provide an important parameter for enhancing carbonation reaction processes. Mg(OH)(sub 2) was chosen as the model material for investigating lamellar hydroxide mineral dehydroxylation/carbonation mechanisms due to (i) its structural and chemical simplicity, (ii) interest in Mg(OH)(sub 2) gas-solid carbonation as a potentially cost-effective CO(sub 2) mineral sequestration process component, and (iii) its structural and chemical similarity to other lamellar-hydroxide-based minerals (e.g., serpentine-based minerals) whose carbonation reaction processes are being explored due to their low-cost CO(sub 2) sequestration potential. Fundamental understanding of the mechanisms that govern dehydroxylation/carbonation processes is essential for minimizing the cost of any lamellar-hydroxide-based mineral carbonation sequestration process. This report covers the third year progress of this grant, as well as providing an integrated overview of the progress in years 1-3, as we have been granted a one-year no-cost extension to wrap up a few studies and publications to optimize project impact

Bio-recovery of non-essential heavy metals by intra- and extracellular mechanisms in free-living microorganisms.

Science.gov (United States)

García-García, Jorge D; Sánchez-Thomas, Rosina; Moreno-Sánchez, Rafael

2016-01-01

Free-living microorganisms may become suitable models for recovery of non-essential and essential heavy metals from wastewater bodies and soils by using and enhancing their accumulating and/or leaching abilities. This review analyzes the variety of different mechanisms developed mainly in bacteria, protists and microalgae to accumulate heavy metals, being the most relevant those involving phytochelatin and metallothionein biosyntheses; phosphate/polyphosphate metabolism; compartmentalization of heavy metal-complexes into vacuoles, chloroplasts and mitochondria; and secretion of malate and other organic acids. Cyanide biosynthesis for extra-cellular heavy metal bioleaching is also examined. These metabolic/cellular processes are herein analyzed at the transcriptional, kinetic and metabolic levels to provide mechanistic basis for developing genetically engineered microorganisms with greater capacities and efficiencies for heavy metal recovery, recycling of heavy metals, biosensing of metal ions, and engineering of metalloenzymes. Copyright © 2016 Elsevier Inc. All rights reserved.

Extraction process

International Nuclear Information System (INIS)

Rendall, J.S.; Cahalan, M.J.

1979-01-01

A process is described for extracting at least two desired constituents from a mineral, using a liquid reagent which produces the constituents, or compounds thereof, in separable form and independently extracting those constituents, or compounds. The process is especially valuable for the extraction of phosphoric acid and metal values from acidulated phosphate rock, the slurry being contacted with selective extractants for phosphoric acid and metal (e.g. uranium) values. In an example, uranium values are oxidized to uranyl form and extracted using an ion exchange resin. (U.K.)

Extraterrestrial Metals Processing, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The Extraterrestrial Metals Processing (EMP) system produces ferrosilicon, silicon monoxide, a glassy mixed oxide slag, and smaller amounts of alkali earth...

Selective flotation of phosphate minerals with hydroxamate collectors

Science.gov (United States)

Miller, Jan D.; Wang, Xuming; Li, Minhua

2002-01-01

A method is disclosed for separating phosphate minerals from a mineral mixture, particularly from high-dolomite containing phosphate ores. The method involves conditioning the mineral mixture by contacting in an aqueous in environment with a collector in an amount sufficient for promoting flotation of phosphate minerals. The collector is a hydroxamate compound of the formula; ##STR1## wherein R is generally hydrophobic and chosen such that the collector has solubility or dispersion properties it can be distributed in the mineral mixture, typically an alkyl, aryl, or alkylaryl group having 6 to 18 carbon atoms. M is a cation, typically hydrogen, an alkali metal or an alkaline earth metal. Preferably, the collector also comprises an alcohol of the formula, R'--OH wherein R' is generally hydrophobic and chosen such that the collector has solubility or dispersion properties so that it can be distributed in the mineral mixture, typically an alkyl, aryl, or alkylaryl group having 6 to 18 carbon atoms.

A fast laser alloying process for the selective electroplating of metal on SiO2 and polyimide

International Nuclear Information System (INIS)

Malba, V.; Bernhardt, A.F.

1992-01-01

This paper reports on a new laser direct-write process for patterning of metal on multichip modules. The process involves the laser modification of the non-conductive surface of a seed multilayer, converting it to a conductive surface, which can be electroplated with metal. The seed multilayer is composed of a TiW adhesion layer, onto which a Au film is sputtered, followed by an a-Si layer, which forms the non-conductive surface. The laser modifies the surface by alloying (or mixing) the Si and Au to form the conductive surface. This laser process has been shown to be capable of writing speeds of 2.5 m/s. With a silicon dioxide interlevel dielectric layer, the process works over a large range of laser power (P max /P min ∼ 5). A polyimide interlevel dielectric layer can be used without damage or loss of adhesion, although the process margin is substantially reduced (P max /P min ∼ 2)