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Sample records for bgc-lurgi slagging process

  1. Process-integrated slag treatment; Prozessintegrierte Schlackebehandlung

    Energy Technology Data Exchange (ETDEWEB)

    Koralewska, R.; Faulstich, M. [Technische Univ., Garching (Germany). Lehrstuhl fuer Wasserguete- und Abfallwirtschaft

    1998-09-01

    The present study compares two methods of washing waste incineration slag, one with water only, and one which uses additives during wet deslagging. The presented aggregate offers ideal conditions for process-integrated slag treatment. The paper gives a schematic description of the integrated slag washing process. The washing liquid serves to wash out the readily soluble constituents and remove the fines, while the additives are for immobilising heavy metals in the slag material. The study is based on laboratory and semi-technical trials on the wet chemical treatment of grate slag with addition of carbon dioxide and phosphoric acid. [Deutsch] Die dargestellten Untersuchungen beziehen sich auf den Vergleich zwischen einer Waesche der Muellverbrennungsschlacke mit Wasser und unter Zugabe von Additiven im Nassentschlacker. In diesem Aggregat bieten sich optimale Voraussetzungen fuer eine prozessintegrierte Schlackebehandlung. Die Durchfuehrung der integrierten Schlackewaesche wird schematisch gezeigt. Durch die Waschfluessigkeit sollen die leichtloeslichen Bestandteile ausgewaschen und die Feinanteile ausgetragen sowie durch die Additive zusaetzlich die Schwermetalle im Schlackematerial immobilisiert werden. Dazu erfolgten Labor- und halbtechnische Versuche zur nasschemischen Behandlung der Rostschlacken unter Zugabe von Kohlendioxid und Phosphorsaeure. (orig./SR)

  2. Process of Re-Resourcing of Converter Slag

    Institute of Scientific and Technical Information of China (English)

    GAO Jin-tao; LI Shi-qi; ZHANG Yan-ting; ZHANG Yan-ling; CHEN Pei-yu; SHEN Ping

    2011-01-01

    The process of "re-resourcing of converter slag" was put forward based on the analysis of the existing steel slag treatment process.The converter slag obtained from Jinan steel plant was studied.After grinding,the slag contained 3.3% of iron particles,54.84% of magnetic part(wTFe=20%),and 41.84% of non-magnetic part,which could be used for making cement directly.At a temperature below 1000 ℃,the non-magnetic Fe2O3 in the slag could be efficiently reduced to magnetic iron by pure H2 and CO.The slag after precise reduction had high degree of dispersion and did not get sintered,which provided an optimum condition for the separation of iron and impurities.To separate the slag and enrich the iron after reduction,the laboratory-scale device of magnetic separation was designed and made.The process of slag re-resourcing,which included magnetic sorting,precise reduction,magnetic separation,and removal of free calcium oxide(f-CaO),was proposed to obtain iron-rich magnetic materials and cement adulterant materials.Through this process,33 kg iron particles,150 kg iron-rich material and 700 kg cement could be obtained in each ton slag.Besides,this process to recycle converter slag had a lower energy and material consumption and no pollutant emission.

  3. Dusting control of magnesium slag produced by Pidgeon process

    Science.gov (United States)

    Wu, Laner; Yang, Qixing; Han, Fenglan; Du, Chun

    2013-06-01

    Magnesium production by Pidgeon process has been developed very fast in China since 1990's. The waste slag from magnesium production has attracted broad attention because the huge amounts of the slag. For each ton of magnesium produced, there will be 6-8 tons of the slag generated. A big part of the Mg slag exists as fine dust with particle size of D95 pollute air, soil and water surrounding the Mg industry. The fine particles are generated by phase transformations of dicalcium silicate C2S (2CaOṡSiO2) during the slag cooling. There is a volume expansion of more than 10% with the transformation of β-C2S to γ-C2S phase, causing a disintegration or dusting of the Mg slag. In the present study, several chemical stabilizers were used to treat the dusting Mg slag at 1200°C, including borates, phosphates and rare earth oxides, in order to obtain volume stable slag aggregates for environmental protection and recycling of the Mg slag. The volume expanding rates of the samples were measured. XRD and SEM studies were carried out to confirm effects of the stabilizers. The results show that all of the stabilizers were effective for the stabilization of Mg slag. Some differences between the stabilizers were also described and discussed.

  4. Processing fine stainless-steel slag using spiral concentration.

    Science.gov (United States)

    Wolfe, Eric R; Klima, Mark S

    2008-04-01

    In this study, the effectiveness of spiral concentration to process a fine (-1 mm) stainless-steel slag was evaluated. Specifically, testing was conducted to determine the feasibility of producing a high metal content stainless steel product and a low metal content aggregate product. This involved investigating a key operating variable for both five-and seven-turn spiral concentrators. The raw slag and spiral products were characterized to determine their respective size and metal distributions. Separation testing was carried out using the two full-scale spiral concentrators to evaluate the effects of feed solids concentration on spiral performance at solids feed rates ranging from 15 to 30 kg/min. The results indicated that under certain conditions, a high-quality metal fraction could be produced. For example, using the five-turn spiral, a product containing 95% metal was obtained at a low metal recovery. Both spirals were ineffective at concentrating the aggregate fraction. Overall, the feed solids concentration did not significantly affect the quality or recoveries of the products, particularly for feed solids concentrations less than 35% by weight. In order to improve the metal recoveries and to produce a low-metal aggregate material, reprocessing of the product streams and/or additional liberation of the raw slag would be required. PMID:18324536

  5. An alternative approach for reusing slags from a plasma vitrification process

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Y.-M. [Department of Safety Health and Environmental Engineering, Chung Hwa University of Medical Technology, 89, Wenhwa 1st St., Rende Shiang, Tainan County 71703, Taiwan (China)], E-mail: yiming@mail.hwai.edu.tw; Tseng, H.-J. [Department of Foundry Engineering, National Tainan Industrial Vocational High School, Tainan 71075, Taiwan (China); Chang, J.-E. [Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Sustainable Environment Research Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Wang, J.-W.; Wang, C.-T. [Department of Safety Health and Environmental Engineering, Chung Hwa University of Medical Technology, 89, Wenhwa 1st St., Rende Shiang, Tainan County 71703, Taiwan (China); Chen, H.-T. [Sustainable Environment Research Center, National Cheng Kung University, Tainan 70101, Taiwan (China)

    2008-08-15

    Vitrification is widely applied to transform hazardous materials into inert slags. Raising the value of the recycled slag is an important issue from an economic point of view. In this study, an alternative approach for mixing a plasma slag with unsaturated polyester resin for making the dough-like molding composites is proposed. Physical properties, including ultimate tensile strength, Rockwell hardness, and the elongation at break, were measured to evaluate the characteristics of the composites. A scanning electron microscope and an X-ray diffractometer were used to examine the micro characteristics of the specimens. The chemical stability of the composites was estimated using the toxicity characteristic leaching procedure and a hot water bathing process. In an optimal slag loading (mass ratio of slag to unsaturated polyester resin) ranged from 0.1 to 0.2, the slag powder improved the physical properties of the composites. With an increased slag loading, excess slag powder weakened the structure of the resin, reducing the ultimate tensile strength and Rockwell hardness. The acid and water bathing tests indicated that the resin is decomposed in a hot environment. However, the slag was not destructed nor were the hazardous metals leached out. The results show that the molding method is an effective technology to recycle the slag.

  6. An alternative approach for reusing slags from a plasma vitrification process.

    Science.gov (United States)

    Kuo, Yi-Ming; Tseng, Ho-Jung; Chang, Juu-En; Wang, Jian-Wen; Wang, Chih-Ta; Chen, Hung-Ta

    2008-08-15

    Vitrification is widely applied to transform hazardous materials into inert slags. Raising the value of the recycled slag is an important issue from an economic point of view. In this study, an alternative approach for mixing a plasma slag with unsaturated polyester resin for making the dough-like molding composites is proposed. Physical properties, including ultimate tensile strength, Rockwell hardness, and the elongation at break, were measured to evaluate the characteristics of the composites. A scanning electron microscope and an X-ray diffractometer were used to examine the micro characteristics of the specimens. The chemical stability of the composites was estimated using the toxicity characteristic leaching procedure and a hot water bathing process. In an optimal slag loading (mass ratio of slag to unsaturated polyester resin) ranged from 0.1 to 0.2, the slag powder improved the physical properties of the composites. With an increased slag loading, excess slag powder weakened the structure of the resin, reducing the ultimate tensile strength and Rockwell hardness. The acid and water bathing tests indicated that the resin is decomposed in a hot environment. However, the slag was not destructed nor were the hazardous metals leached out. The results show that the molding method is an effective technology to recycle the slag. PMID:18243535

  7. Determination of Cu recovery degree from slags in shaft process by means of radiotracers

    International Nuclear Information System (INIS)

    A radiotracer method has been used for determining the recovery degree of copper from slags after converter and flash furnace processing. Re-processing of slags was carried out in a commercial shaft furnace. The tracer used was 64Cu in forms of pure metal, sulphide or oxide. The method applied has been described and the results of experiments presented. (author)

  8. Computational Fluid Dynamic Modeling of Zinc Slag Fuming Process in Top-Submerged Lance Smelting Furnace

    Science.gov (United States)

    Huda, Nazmul; Naser, Jamal; Brooks, Geoffrey; Reuter, Markus A.; Matusewicz, Robert W.

    2012-02-01

    Slag fuming is a reductive treatment process for molten zinciferous slags for extracting zinc in the form of metal vapor by injecting or adding a reductant source such as pulverized coal or lump coal and natural gas. A computational fluid dynamic (CFD) model was developed to study the zinc slag fuming process from imperial smelting furnace (ISF) slag in a top-submerged lance furnace and to investigate the details of fluid flow, reaction kinetics, and heat transfer in the furnace. The model integrates combustion phenomena and chemical reactions with the heat, mass, and momentum interfacial interaction between the phases present in the system. A commercial CFD package AVL Fire 2009.2 (AVL, Graz, Austria) coupled with a number of user-defined subroutines in FORTRAN programming language were used to develop the model. The model is based on three-dimensional (3-D) Eulerian multiphase flow approach, and it predicts the velocity and temperature field of the molten slag bath, generated turbulence, and vortex and plume shape at the lance tip. The model also predicts the mass fractions of slag and gaseous components inside the furnace. The model predicted that the percent of ZnO in the slag bath decreases linearly with time and is consistent broadly with the experimental data. The zinc fuming rate from the slag bath predicted by the model was validated through macrostep validation process against the experimental study of Waladan et al. The model results predicted that the rate of ZnO reduction is controlled by the mass transfer of ZnO from the bulk slag to slag-gas interface and rate of gas-carbon reaction for the specified simulation time studied. Although the model is based on zinc slag fuming, the basic approach could be expanded or applied for the CFD analysis of analogous systems.

  9. MICROSTRUCTURAL STUDY OF THE LD CONVERTER SLAG AND ITS RELATIONSHIP TO THE DEPHOSPHORISATION PROCESS

    Directory of Open Access Journals (Sweden)

    Hugo Filipe Parreiras Gonçalves

    2014-03-01

    Full Text Available The LD converter slag plays an important role in the refining process, mainly in relationship to phosphorus removal. Much is known about the physicochemical characteristics of the slag and its relationship to the process efficiency; however few employ the microstructural aspect for such analysis. In this sense, the aim of this work was to analyze the slag microstructure formed at Usiminas converters and to understand important points relationed to dephosphorisation reaction, to act efficiently in the industrial process improvement. It was verified that dephosphorisation reaction does not occur in slag solid phases. According to this observation, the amount of fluxes added to the converter was reviewed, reaching a considerable reduction in the free CaO content of the slags. It was also observed a drop of approximately 10% in lime consumption at the converters, without influence in the mean phosphorus content at the end of oxygen blown.

  10. Evaluation of copper slag to catalyze advanced oxidation processes for the removal of phenol in water

    Energy Technology Data Exchange (ETDEWEB)

    Huanosta-Gutierrez, T. [Instituto de Ingenieria, Coordinacion de Ingenieria Ambiental, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, Coyoacan 04510, Mexico, D.F. (Mexico); Dantas, Renato F., E-mail: falcao@angel.qui.ub.es [Departament d' Enginyeria Quimica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Ramirez-Zamora, R.M. [Instituto de Ingenieria, Coordinacion de Ingenieria Ambiental, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, Coyoacan 04510, Mexico, D.F. (Mexico); Esplugas, S. [Departament d' Enginyeria Quimica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer We evaluate the use of an industrial residue (copper slag) as catalyst in water treatment. Black-Right-Pointing-Pointer The copper slag was effective to remove organic pollutants (phenol) from water. Black-Right-Pointing-Pointer During experimentation, Cu and Fe leaching were not higher than the acceptable levels. Black-Right-Pointing-Pointer Slag/H{sub 2}O{sub 2}/UV and slag/H{sub 2}O{sub 2} treatments promoted biodegradability increment of the contaminated water. Black-Right-Pointing-Pointer The control of the reaction time would minimize the environmental impact of the produced effluents in terms of acute toxicity. - Abstract: The aim of this work was to evaluate the use of copper slag to catalyze phenol degradation in water by advanced oxidation processes (AOPs). Copper slag was tested in combination with H{sub 2}O{sub 2} (slag/H{sub 2}O{sub 2}) and H{sub 2}O{sub 2}/UV (slag/H{sub 2}O{sub 2}/UV). The studied methods promoted the complete photocatalytic degradation of phenol. Besides, they were able to reduce about 50% the TOC content in the samples. Slag/H{sub 2}O{sub 2}/UV and slag/H{sub 2}O{sub 2} treatments have favored biodegradability increment along the reaction time. Nevertheless, the irradiated method achieved higher values of the biodegradability indicator (BOD{sub 5}/TOC). The toxicity assessment indicated the formation of more toxic compounds in both treatments. However, the control of the reaction time would minimize the environmental impact of the effluents.

  11. Intensification of the electro slag process exothermic mixtures (fluxеs)

    OpenAIRE

    Власов, А. Ф.; Макаренко, Н. О.; Чигарьов, Валерій Васильович

    2015-01-01

    It is established that an effective way to improve performance is to use the electro slag processes exothermic mixture (mechanical mixture scaling of aluminum powder and а standard flux) or flux exothermic (mechanical scaling mixtures, alloys, aluminum powder and a flux standard) in amounts sufficient for the exothermal reaction. Experimentally is defined the presence of the electrically conductive layer exothermic flux, allowing to carry out the electro slag process mono, bifilar or three-ph...

  12. Sulfur behaviour on stainless steel melting by single-slag process

    International Nuclear Information System (INIS)

    A consideration is given to desulfurizing process during melting stainless steel type 08-12Kh18N10T according to a single-slag variant of melting technology. Wastes of abrasive metal machining and worn-out equipment from chemical plants are shown to be highly contaminated with sulfur and cannot be remelted by the above-mentioned process. A new variant of two-slag melting technology was successfully tested. 4 refs

  13. Synthesis and Characterization of Titanium Slag from Ilmenite by Thermal Plasma Processing

    Science.gov (United States)

    Samal, Sneha

    2016-02-01

    Titanium rich slag has emerged as a raw material for alternative titanium source. Ilmenite contains 42-50% TiO2 as the mineralogical composition depending on the geographical resources. Application of titanium in paper, plastic, pigment and other various industries is increasing day by day. Due to the scarcity of natural raw mineral rutile (TiO2), ilmenite is considered as precursor for the extraction of TiO2. Ilmenite is reduced at the initial stage for the conversion of complex iron oxide into simpler form. Therefore, pre-reduction of ilmenite concentrate is essential to minimize the energy consumption during thermal plasma process. Thermal plasma processing of ilmenite for the production of titania rich slag is considered to be the direct route to meet the current demand of industrial needs of titanium. Titania rich slag contains 70-80% TiO2 as the major component with some other minor impurities, like oxide phases of Si, Al, Cr, Mg, Mn, Ca, etc. Usually titanium is present in tetravalent forms with globular metallic iron in the slag. Titania rich slag undergoes leaching for the removal of iron and transforming the slag into synthetic rutile having 85-95% of TiO2.

  14. The influence of different parameters on the hydration process of binders based on alkali activated slag

    Directory of Open Access Journals (Sweden)

    DARKO KRIZAN

    2005-02-01

    Full Text Available The influence of certain types of activators (water glass Na2O·nSiO2 and sodium-metasilicate Na2SiO3·5H2O on the hydration process of alkali activated slag was investigated in this study. The influence of activator concentration, specific surface area of the slag and the modulus n of the water glass (mass ratio between SiO2 and Na2O on the kinetics of the hydration process i.e., the change of compressive strength were also investigated. Poorly crystallized low base calcium silicate hydrate C–S–H (I is the main hydration product of alkali activated slag regardless of the activator used. This is the reason for the rapid increase in the strength of alkali activated slag and also of the very high strength values. The strength growth rate and strength values were significantly higher when sodium–metasilicate was used as the activator than when water glass was used. The specific surface area of the slag and the activator concentration are parameters which have a closely connected influence on strength and their action is cumulative. The modulus n of water glass does not have an explicit influence on the strength of alkali activated slag.

  15. The Concept of Slag Decopperisation in the Flash Furnace Process by Use of Complex Reagents

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    Bydałek A.W.

    2015-04-01

    Full Text Available The article presents an outline of the new technology of pyrometallurgical processing of slag in the direct-to-blister process. The analysis is based on the example of the production process of KGHM Polish Copper SA. A new way of implementing the technology of recovery of copper from the flash furnace slag by means of different feedstocks has been proposed. The method of controlling the processes is another innovation discussed in the paper. The presented concept intensify the reduction reactions, using the Carbo-N-Ox method, of copper compounds to forms of metallic phases in the slag. The processes of coagulation are accelerated and the processes crystallization of metallic phases are under control.

  16. Evaluation of the economic feasibility of a processing plant for steelmaking slag.

    Science.gov (United States)

    Gonçalves, Deyvid R R; Fontes, Wanna C; Mendes, Julia C; Silva, Guilherme J B; Peixoto, Ricardo A F

    2016-02-01

    The utilisation of steelmaking slag as recycled aggregate for concretes is a widely investigated solution for mitigating the expenditure and environmental impacts of its storage. The Brazilian steel industry is investing in research and slag reprocessing practices, aiming to reuse most of its metallic fraction and properly allocate the non-metallic fraction, saving energy and reducing mining impacts. Research results demonstrate the technical and environmental feasibility of steel slag aggregates for civil construction. However, it is essential to evaluate whether the processing of the slag is economically feasible for this purpose. Economic analysis of the processing of steel slag was conducted through simulation - Monte Carlo method - in which it is possible to determine the risks and uncertainties inherent to the project. The costs that comprise the proposed project, from design through construction and operation itself, were estimated at US$2.8 million. The result of the simulation indicates economic feasibility of the project with 98% certainty, and an estimated profit of around 42%. PMID:26634879

  17. Statistical modeling of copper losses in the silicate slag of the sulfide concentrate smelting process

    Directory of Open Access Journals (Sweden)

    Savic Marija V.

    2015-09-01

    Full Text Available This article presents the results of the statistical modeling of copper losses in the silicate slag of the sulfide concentrates smelting process. The aim of this study was to define the correlation dependence of the degree of copper losses in the silicate slag on the following parameters of technological processes: SiO2, FeO, Fe3O4, CaO and Al2O3 content in the slag and copper content in the matte. Multiple linear regression analysis (MLRA, artificial neural networks (ANNs and adaptive network based fuzzy inference system (ANFIS were used as tools for mathematical analysis of the indicated problem. The best correlation coefficient (R2 = 0.719 of the final model was obtained using the ANFIS modeling approach.

  18. Effect of PCs superplasticizers on the rheological properties and hydration process of slag-blended cement pastes

    OpenAIRE

    Palacios, M.; Puertas, F.; Bowen, P.; Houst, Y. F.

    2009-01-01

    The effect of polycarboxylate (PC) superplasticizers with different structure on the rheological properties and hydration process of slag-blended cement pastes with a slag content between 0 and 75% has been studied. Fluidizing properties of PCs admixtures are significantly higher in slag-blended cement with respect to non-blended Portland cement. Also, it has been observed that the rise of the fluidity induced by the PCs on the cement pastes increases with the slag content. This effect is mainl...

  19. The Mechanical Properties of Foamed Concrete containing Un-processed Blast Furnace Slag

    OpenAIRE

    Awang H.; Aljoumaily Z. S.; Noordin N.; Al-Mulali M. Z.

    2014-01-01

    For many years, supplementary cementation materials have been utilized as cement or filler replacements to heighten the properties of concrete. The objective of this paper is to demonstrate the effects of un-processed blast furnace slag (RS) on the compressive, splitting tensile and flexural strengths of foam concrete over periods of 7, 14 and 28 days. The introduction of slag to the cement begins at 30% and rises to 70% of the total content. Six mixes, which include the control mix with a si...

  20. The Mechanical Properties of Foamed Concrete containing Un-processed Blast Furnace Slag

    Directory of Open Access Journals (Sweden)

    Awang H.

    2014-01-01

    Full Text Available For many years, supplementary cementation materials have been utilized as cement or filler replacements to heighten the properties of concrete. The objective of this paper is to demonstrate the effects of un-processed blast furnace slag (RS on the compressive, splitting tensile and flexural strengths of foam concrete over periods of 7, 14 and 28 days. The introduction of slag to the cement begins at 30% and rises to 70% of the total content. Six mixes, which include the control mix with a similar mix ratio (1:2:0.45 and a dry density of 1300 kg/m3 is generated. Taking into consideration, from the total weight of the cementation material, 1% of super- plasticizer (PS-1 is added to the mixes with slag content. Test results revealed that the most favourable (optimum replacement level of un-processed slag in foam concrete is 30%. This represents a commercial advantage as the cement requirement is reduced from 414 Kg/m3 to 290 Kg/m3. On the 28th day, the optimum mix showed higher values than the control mix by 32% for compressive strength, 46.5% for splitting tensile strength and 61% for flexural strength.

  1. Removal of hexavalent chromium in carbonic acid solution by oxidizing slag discharged from steelmaking process in electric arc furnace

    Science.gov (United States)

    Yokoyama, Seiji; Okazaki, Kohei; Sasano, Junji; Izaki, Masanobu

    2014-02-01

    Hexavalent chromium (Cr(VI)) is well-known to be a strong oxidizer, and is recognized as a carcinogen. Therefore, it is regulated for drinking water, soil, groundwater and sea by the environmental quality standards all over the world. In this study, it was attempted to remove Cr(VI) ion in a carbonic acid solution by the oxidizing slag that was discharged from the normal steelmaking process in an electric arc furnace. After the addition of the slag into the aqueous solution contained Cr(VI) ion, concentrations of Cr(VI) ion and total chromium (Cr(VI) + trivalent chromium (Cr(III)) ions decreased to lower detection limit of them. Therefore, the used slag could reduce Cr(VI) and fix Cr(III) ion on the slag. While Cr(VI) ion existed in the solution, iron did not dissolve from the slag. From the relation between predicted dissolution amount of iron(II) ion and amount of decrease in Cr(VI) ion, the Cr(VI) ion did not react with iron(II) ion dissolved from the slag. Therefore, Cr(VI) ion was removed by the reductive reaction between Cr(VI) ion and the iron(II) oxide (FeO) in the slag. This reaction progressed on the newly appeared surface of iron(II) oxide due to the dissolution of phase composed of calcium etc., which existed around iron(II) oxide grain in the slag.

  2. Reaction Process of Chromium Slag Reduced by Industrial Waste in Solid Phase

    Institute of Scientific and Technical Information of China (English)

    SHI Yu-min; DU Xing-hong; MENG Qing-jia; SONG Shi-wei; SUI Zhi-tong

    2007-01-01

    M, a particular industrial waste, was selected to detoxify chromium slag at a high temperature. The carbon remaining in M reduced Cr (Ⅵ) of Na2CrO4 borne in the chromium slag to Cr (Ⅲ) in the solid phase reaction, and its thermodynamics and kinetics were studied. The reduction process of Na2CrO4 by carbon produced CO, which was endothermic. Under the experimental condition, the apparent activation energy was 4.41 kJ·mol-1, the apparent order of reaction for Na2CrO4 was equal to one, and the partial pressure of CO was only 0.22 Pa at 1 330 ℃.

  3. 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.

  4. 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)

    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 SiO2/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

  5. ATMOSPHERE POLLUTION AT STORAGE OF SLAGS OF ALUMINIUM SECONDARY PROCESSING

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    A. S. Panasyugin

    2015-05-01

    Full Text Available Thermodynamic probability of the processes of the formation of compounds of aluminum (which release in the environment by hydrolysis ammonia, acetylene, propane and hydrogen sulfide is determined. In the article the economic loss from irrecoverable waste of aluminum and fines for emissions of air pollutants is estimated.

  6. ATMOSPHERE POLLUTION AT STORAGE OF SLAGS OF ALUMINIUM SECONDARY PROCESSING

    OpenAIRE

    A. S. Panasyugin; D. P. Mihalap; S. A. Panasyugin; N. D. Pavlovsky; Z. N. Chipurko

    2015-01-01

    Thermodynamic probability of the processes of the formation of compounds of aluminum (which release in the environment by hydrolysis ammonia, acetylene, propane and hydrogen sulfide) is determined. In the article the economic loss from irrecoverable waste of aluminum and fines for emissions of air pollutants is estimated.

  7. Studying properties of carbonaceous reducers and process of forming primary titanium slags

    Directory of Open Access Journals (Sweden)

    T. K. Balgabekov

    2014-10-01

    Full Text Available When smelting a rich titanium slag the most suitable are low-ash reducers, and the studies revealed the suitability for this purpose of special coke and coal. An important property of a reducer is its specific resistance. Therefore there were carried out studies for measuring electric resistance of briquettes consisting of ilmenite concentrate and different carbonaceous reducers. It is recommended to jointly smelt the briquetted and powdered burden (the amount of the powdered burden varies form 20 tо 50 %, this leads to the increase of technical-economic indicators of the process.

  8. Alkaline-sulphate activation processes of a Spanish blast furnace slag

    OpenAIRE

    Fernández Jiménez, A.; Puertas, F.; Fernández-Carrasco, L.

    1996-01-01

    Alkaline-sulphate activation processes of a Spanish granulated blast furnace slag (Avilés, Ensidesa) have been studied. Activator solutions used were: deionized water (as reference solution), Ca(OH)2 (3,5∙10-3N), NaOH (1N), Na2CO3 (2N), CaSO4∙2H2O (3,0∙10-3N) at 25ºC. The influence of the nature of alkaline or sulphate solution cation...

  9. Kinetics of Copper Reduction from Molten Slags

    OpenAIRE

    Tesfaye, Fiseha

    2009-01-01

    The objective of this thesis was to study the process of reduction of cuprous oxide by carbon from copper flash smelting slags. The flash smelting and slag cleaning processes are described in the introductory part. The studies are focused on the slag cleaning process in the three - electrode electric furnace (EF), where components of the slag reduce to matte and EF slag in a periodic batch process. Parametric values of different variables (surface energy, density, viscosity, and equilibri...

  10. Developments in gold and silver recovery through flotation in processing of gold ore slags

    International Nuclear Information System (INIS)

    The aim of this work is to recover and improve the extraction of gold and silver present in smelting slags through various mineralogical processes applicable in gold ores. The slag was concentrated in a Knelson type centrifuge, two concentrates (C1 and C2 and a tailing T1) being obtained. In order to improve the recovery, three series of rougher flotation tests were conducted on the tailing T1. The variables analyzed were: particle size, type of collectors (xanthates, di-monothiophosphate) and flotation time. It was deduced that by applying gravity concentration, the recovery of Au and Ag (Knelson centrifuge) is 42.0% and 13.7%, respectively. Au recovery is improved by 87.7% through the flotation of the centrifuge separation tailings, whereas that for Ag is 47.4%. The optimum conditions were: particle size 200 mesh, collectors: PAX (15.8 g/t), F-C5439 (18.75 g/t), MIBC frother (12.5g/t) and 8.5 minutes of flotation time. (Author)

  11. Characterization and immobilization of white slag from secondary metallurgical processes in cementitious composites

    OpenAIRE

    Zalar Serjun, Vesna

    2015-01-01

    The fundamental objective of this study was to define such a cement composite with the addition of white (ladle) slag, which will provide functionality for selected purposes and furthermore, prevent the leaching of toxic elements into the environment. The recovery (recycling) of secondary metallurgical slags from stainless steel production has an important synergistic impact on the environment. In this study, detailed characterization of slag derived from two different ladle refin...

  12. Alkaline-sulphate activation processes of a Spanish blast furnace slag

    Directory of Open Access Journals (Sweden)

    Fernández Jiménez, A.

    1996-03-01

    Full Text Available Alkaline-sulphate activation processes of a Spanish granulated blast furnace slag (Avilés, Ensidesa have been studied. Activator solutions used were: deionized water (as reference solution, Ca(OH2 (3,5∙10-3N, NaOH (1N, Na2CO3 (2N, CaSO4∙2H2O (3,0∙10-3N at 25ºC. The influence of the nature of alkaline or sulphate solution cation on slag activation process was verified. Sodium solutions decrease the induction period while calcium solutions increase it. Slag reaction degree was also determined, likewise the nature of the different reaction products formed as a function of the activator solution nature.

    Se han estudiado los procesos de activación alcalinosulfáticos de una escoria granulada de alto horno española (Avilés, Ensidesa. Las disoluciones activantes utilizadas fueron: H2O desionizada (como disolución de referencia, Ca(OH2 (3,5∙10-3N, NaOH (1N, Na2CO3 (2N, CaSO4∙2H2O (3,0∙10-3N a 25ºC. Se ha comprobado la influencia de la naturaleza del catión de la disolución alcalina o sulfática sobre el proceso de activación de la escoria. Las disoluciones sódicas disminuyen el período de inducción, mientras que las disoluciones cálcicas lo incrementan. También se determinó el grado de reacción de la escoria, así como la naturaleza de los distintos productos de reacción formados, en función de la naturaleza de la disolución activante.

  13. The estimation slag refining features for the Cu-Si alloys melting process

    OpenAIRE

    A. W. Bydałek; A. Bydałek; K. Najman; P. Schlafka

    2008-01-01

    In thc papcr a rncthod of determining the rcduclion capability of slag solutions was uscd. Thc cxtraction of mcrallurgical slag during thcpmccss of rnclting of coppcr alfoys can bc imcnsificd hy addition of carbides. To anatysc thc proccss author has made an cCfort to cstimatcrefining cfficicncy ~Fcornplicatcdse ts of rcagcnts in rcal industrial systems. Thc papcr prcscnts thc analysis o f ~hscta te of art in thc ficldof metallurgy aFsiticium bronze.

  14. Stainless steel denitriding with slag

    International Nuclear Information System (INIS)

    Calculation and experimental methods were used to investigate the process of titanium nitride formation when alloying chromium nickel stainless steels with titanium. At common concentrations of titanium and nitrogen, titanium nitrides were observed to be precipitated from the melt into slag in amounts of 0.1% and more. The laboratory study of the slag influence of the process of steel refining from titanium nitrides showed that the slag containing calcium, aluminium and magnesium oxides is favourable to the denitriding of steel. In addition, the possibility of direct transition of dissolved nitrogen from the metal into the slag is revealed. 7 refs., 1 fig., 2 tabs

  15. Modeling of a self-healing process in blast furnace slag cement exposed to accelerated carbonation

    International Nuclear Information System (INIS)

    In the current research, a mathematical model for the post-damage improvement of the carbonated blast furnace slag cement (BFSC) exposed to accelerated carbonation is constructed. The study is embedded within the framework of investigating the effect of using lightweight expanded clay aggregate, which is incorporated into the impregnation of the sodium mono-fluorophosphate (Na-MFP) solution. The model of the self-healing process is built under the assumption that the position of the carbonation front changes in time where the rate of diffusion of Na-MFP into the carbonated cement matrix and the reaction rates of the free phosphate and fluorophosphate with the components of the cement are comparable to the speed of the carbonation front under accelerated carbonation conditions. The model is based on an initial-boundary value problem for a system of partial differential equations which is solved using a Galerkin finite element method. The results obtained are discussed and generalized to a three-dimensional case.

  16. Microstructural characterisation of chromium slags

    OpenAIRE

    Burja, J.; F. Tehovnik; Vode, F.; Arh, B.

    2015-01-01

    In this chromium slags that form during melting of chromium alloyed steels are examined. During melting and oxidation of these steel grades a considerable amount of chromium is lost, and gained back with slag reduction. Laboratory experiments were performed to study the mechanism of chromium oxide reduction by silicon. Slags chemistry and phase composition have a strong effect on the steelmaking process. Phase analysis revealed two types of chromium oxides, calcium chromites and chromite spin...

  17. Hydraulic properties of ladle slags

    Directory of Open Access Journals (Sweden)

    J. Vlček

    2016-07-01

    Full Text Available The article presents results of examining of hydraulic properties of ladle slags formed during production of steel. The studied ladle slags were subjected to different cooling mode from the molten state. Based on the ability of the slag react with the water was assessed their hydraulic activity. The hydraulic properties are caused by the presence of minerals dicalcium silicate, tricalcium aluminate, mayenite, brownmillerite and dicalcium ferite. The emergence of required hydrating phases in the ladle slags is conditioned by a sufficient CaO content and their cooling rate. The contact the slag with water during processing and their ageing has a negative effect. The experiment has shown that the phase transformation of the mineral dicalcium silicate which occurs during cooling of the ladle slags cause their volume instability.

  18. PHOSPHORUS REMOVAL USING STEEL SLAG

    Institute of Scientific and Technical Information of China (English)

    Y.Z. Lan; S. Zhang; J.K. Wang; R. W. Smith

    2006-01-01

    Steel slag is a byproduct produced in large amounts in the steel-making process. It is an important resource that can be effectively utilized. An experiment was described in which steel slag was tested as an adsorbent for the removal of phosphorus from waste water. Phosphorus removal depended on the amount of steel slag added, the pH value, the contact time, and the initial concentration. Under laboratory conditions when the added slag was 7.5g/L, the contact time 2h, and the pH value was equivalent to 6.5, over 99% of the phosphorus was removed; the experimental data on steel slag adsorption of phosphorus in the water fitted the Freundlich isotherm model. Steel slag was found to be very effective in adsorbing phosphorus.

  19. UTILIZATION OF ELECTRIC STEEL­SMELTING SLAGS

    Directory of Open Access Journals (Sweden)

    A. I. Pankovets

    2013-01-01

    Full Text Available There are not enough of production facilities on crushing of newly-formed slag due to increase of production volume on steel smelting. The tendencies of slag-processing at OAO «BMZ» are considered.

  20. Influence Of Temperature On The Rate Of Copper Recovery From The Slag Of The Flash Direct-To-Blister Process By A Solid Carbon Reducer

    Directory of Open Access Journals (Sweden)

    Madej P.

    2015-09-01

    Full Text Available The aim of the work was to investigate the influence of temperature on the rate of copper removal from the obtained slag from the flash direct-to-blister process by means of a carbon reducer. The slag used in this work was taken from the direct-to-blister Outokumpu flash furnace at the smelter in Głogów, and graphite penetrators were used as the slag reducers. The experiment was carried out at 1573 K, 1623 K and 1673 K. It was found that the rate of the de-coppering process of the “Głogów” slag increased with the increase of temperature.

  1. Numerical Simulation of the Interaction Between Supersonic Oxygen Jets and Molten Slag-Metal Bath in Steelmaking BOF Process

    Science.gov (United States)

    Li, Qiang; Li, Mingming; Kuang, Shibo; Zou, Zongshu

    2015-02-01

    The impinging of multiple jets onto the molten bath in the BOF steelmaking process plays a crucial role in reactor performance but is not clearly understood. This paper presents a numerical study of the interaction between the multiple jets and slag-metal bath in a BOF by means of the three-phase volume of fluid model. The validity of the model is first examined by comparing the numerical results with experimental measurement of time-averaged cavity dimensions through a scaled-down water model. The calculated results are in reasonably good agreement with the experimental data. The mathematical model is then used to investigate the primary transport phenomena of the jets-bath interaction inside a 150-ton commercial BOF under steelmaking conditions. The numerical results show that the cavity profile and interface of slag/metal/gas remain unstable as a result of the propagation of surface waves, which, likely as a major factor, governs the generation of metal droplets and their initial spatiotemporal distribution. The total momentum transferred from the jets into the bath is consumed about a half to drive the movement of slag, rather than fully converted as the stirring power for the metal bath. Finally, the effects of operational conditions and fluid properties are quantified. It is shown that compared to viscosity and surface tension of the melts, operating pressure and lance height have a much more significant impact on the slag-metal interface behavior and cavity shape as well as the fluid dynamics in the molten bath.

  2. Modeling of a self-healing process in blast furnace slag cement exposed to accelerated carbonation

    NARCIS (Netherlands)

    Zemskov, S.V.; Ahmad, B.; Copuroglu, O.; Vermolen, F.J.

    2013-01-01

    In the current research, a mathematical model for the post-damage improvement of the carbonated blast furnace slag cement (BFSC) exposed to accelerated carbonation is constructed. The study is embedded within the framework of investigating the effect of using lightweight expanded clay aggregate, whi

  3. Slags in steel making; Kuonat teraeksen valmistuksessa

    Energy Technology Data Exchange (ETDEWEB)

    Haerkki, J.; Paeaetalo, M.; Karhu, P.; Jauhiainen, A.; Alamaeki, P.; Koski-Laine, S.; Ollila, J. [Oulu Univ. (Finland). Dept. of Process Engineering

    1996-12-31

    At the first step of the project all stages of the steelmaking processes were viewed from the blast furnace to the continuous casting. Slag knowledge of each processes were collected into a guide, which is meant to help both production and research. At the same time the essential problems caused by slags in steelmaking were focused. At the second step the focus of this slag-project were transferred into the desulphurization, converter, ladle and tundish slags. Wide slag knowledge has been divided into smaller parts and applied versatile into the steelmaking process taking into account the metallurgical, economical and qualitative aspects. (orig.) SULA 2 Research Programme; 13 refs.

  4. Performance of separation processes for precipitated calcium carbonate produced with an innovative method from steelmaking slag and carbon dioxide

    Directory of Open Access Journals (Sweden)

    Sebastian eTeir

    2016-02-01

    Full Text Available In this work, experiments were performed to determine the filterability of calcium carbonate produced with an alternative calcium carbonate production concept. The concept uses steelmaking slag as raw material and has potential to fix CO2 emissions and utilize steelmaking slag, simultaneously. As calcium carbonate is precipitated in a solution containing ammonium chloride, calcium chloride and ammonia, the product needs to be washed and hence filtered. In this work different separation processes, including washing, filtering and drying, were tested on two calcium carbonate slurries produced from steel converter slag and CO2 by a laboratory-scale pilot facility, with the aim of obtaining a solid product with a low chloride content using a minimum amount of washing water. The order of maximum filtration rates achievable of the calcium carbonate slurries was determined by experimental work. The tests included pressure filtration and vacuum filtration and the test series contained altogether 21 different filtration cycles with varying combinations of filtering, washing, and drying steps. The filtered cakes were analyzed by their residual moisture content, chloride content and conductivity, and the filtrates by their residual solids content, chloride content and conductivity. Pressure filtration gave a high capacity (400-460 kg/m2h and a low cake residual moisture content (12-14 wt-%. Vacuum filtration gave slightly higher filtration rates (500-610 kg/m2h at the lowest residual chloride contents of the cakes, but the cake residual moisture also stayed higher (25-26 wt-%. As the vacuum filtration tests used a filter cloth with higher permeability than that of the pressure filtration tests, a slightly higher filtration rate was expected. However, both filtration technologies seem suitable for filtering and washing calcium carbonate prepared with the studied method as a residual chloride content as low as 10 ppm of the filtered solids can be achieved

  5. Evaluation of processing rate and reaction products in the polymeric material furnace using the molten slag

    International Nuclear Information System (INIS)

    A prototype furnace, which adopted the new technique for combusting the polymeric material, was manufactured. In this furnace, the polymeric materials such as rubber were fed to molten slag. The ash, generated at the surface of the polymeric material, dissolved into melt, which promoted the surface combustion of the fixed carbon. The advantages of the new furnace are: (1) High treating rate was realized at so low air excessive ratio as 0.5 ∼ 0.7. (2) The fineness of the unburned particles made the combustion in the after burner easy. (3) The reduction of flying ash coming from the gasification zone lowered the load of the ceramic filters. (author)

  6. Evaluation of electric arc furnace-processed steel slag for dermal corrosion, irritation, and sensitization from dermal contact.

    Science.gov (United States)

    Suh, Mina; Troese, Matthew J; Hall, Debra A; Yasso, Blair; Yzenas, John J; Proctor, Debora M

    2014-12-01

    Electric arc furnace (EAF) steel slag is alkaline (pH of ~11-12) and contains metals, most notably chromium and nickel, and thus has potential to cause dermal irritation and sensitization at sufficient dose. Dermal contact with EAF slag occurs in many occupational and environmental settings because it is used widely in construction and other industrial sectors for various applications including asphaltic paving, road bases, construction fill, and as feed for cement kilns construction. However, no published study has characterized the potential for dermal effects associated with EAF slag. To assess dermal irritation, corrosion and sensitizing potential of EAF slag, in vitro and in vivo dermal toxicity assays were conducted based on the Organisation for Economic Co-operation and Development (OECD) guidelines. In vitro dermal corrosion and irritation testing (OECD 431 and 439) of EAF slag was conducted using the reconstructed human epidermal (RHE) tissue model. In vivo dermal toxicity and delayed contact sensitization testing (OECD 404 and 406) were conducted in rabbits and guinea pigs, respectively. EAF slag was not corrosive and not irritating in any tests. The results of the delayed contact dermal sensitization test indicate that EAF slag is not a dermal sensitizer. These findings are supported by the observation that metals in EAF slag occur as oxides of low solubility with leachates that are well below toxicity characteristic leaching procedure (TCLP) limits. Based on these results and in accordance to the OECD guidelines, EAF slag is not considered a dermal sensitizer, corrosive or irritant. PMID:24395402

  7. Preparation of Slag Wool by Integrated Waste-Heat Recovery and Resource Recycling of Molten Blast Furnace Slags: From Fundamental to Industrial Application

    OpenAIRE

    Dawei Zhao; Zuotai Zhang; Xulong Tang; Lili Liu; Xidong Wang

    2014-01-01

    The present paper investigated the process of the slag wool fabrication using high temperature blast furnace (BF) slag modified by coal ash (CA). The liquidus temperature and viscosity of the slag system with different mass ratios of BF slag and CA were measured through an inner cylinder rotation method. The approximate mass ratio used to fabricate the slag wool was therefore determined and slag wool was then successfully prepared with a high-speed air injection method in the laboratory. The ...

  8. Effects of Basicity and MgO in Slag on the Behaviors of Smelting Vanadium Titanomagnetite in the Direct Reduction-Electric Furnace Process

    Directory of Open Access Journals (Sweden)

    Tao Jiang

    2016-05-01

    Full Text Available The effects of basicity and MgO content on reduction behavior and separation of iron and slag during smelting vanadium titanomagnetite by electric furnace were investigated. The reduction behaviors affect the separation of iron and slag in the direct reduction-electric furnace process. The recovery rates of Fe, V, and Ti grades in iron were analyzed to determine the effects of basicity and MgO content on the reduction of iron oxides, vanadium oxides, and titanium oxides. The chemical compositions of vanadium-bearing iron and main phases of titanium slag were detected by XRF and XRD, respectively. The results show that the higher level of basicity is beneficial to the reduction ofiron oxides and vanadium oxides, and titanium content dropped in molten iron with the increasing basicity. As the content of MgO increased, the recovery rate of Fe increased slightly but the recovery rate of V increased considerably. The grades of Ti in molten iron were at a low level without significant change when MgO content was below 11%, but increased as MgO content increased to 12.75%. The optimum conditions for smelting vanadium titanomagnetite were about 11.38% content of MgO and quaternary basicity was about 1.10. The product, vanadium-bearing iron, can be applied in the converter steelmaking process, and titanium slag containing 50.34% TiO2 can be used by the acid leaching method.

  9. Effect of slag composition on the cleanliness of 28MnCr5 gear steel in the refining processes

    Science.gov (United States)

    Dong, Wen-liang; Ni, Hong-wei; Zhang, Hua; Lü, Ze-an

    2016-03-01

    The equilibrium reaction between CaO—Al2O3—SiO2—MgO slag and 28MnCr5 molten steel was calculated to obtain the suitable slag composition which is effective for decreasing the oxygen content in molten steel. The dissolved oxygen content [O] in molten steel under different top slag conditions was calculated using a thermodynamic model and was measured using an electromotive force method in slag-steel equilibrium experiments at 1873 K. The relations among [O], the total oxygen content (T.O), and the composition of the slag were investigated. The experimental results show that both [O] and T.O decrease with decreasing SiO2 content of the slag and exhibit different trends with the changes in the CaO/Al2O3 mass ratio of the slag. Increasing the CaO/Al2O3 mass ratio results in a decrease in [O] and an increase in T.O. To ensure that T.O ≤ 20 ppm and [O] ≤ 10 ppm, the SiO2 content should be controlled to <5wt%, and the CaO/Al2O3 mass ratio should be in the range from 1.2 to 1.6.

  10. Petroleum coke slags :characterization and dissolution

    OpenAIRE

    Lu, Jun

    1997-01-01

    Slags are crystalline to vitreous by-product materials generated in many high temperature industrial processes. This study presents a general technique for the identification of the phases present in petroleum coke gasification slags. documents the phase assemblages and textures, and finally determines the dissolution of vanadium from these slags as part of the considerations of potential resource reclamation. The general identification procedure utilizes (1) recognition of separa...

  11. Development of a Steel-Slag-Based, Iron-Functionalized Sorbent for an Autothermal Carbon Dioxide Capture Process.

    Science.gov (United States)

    Tian, Sicong; Jiang, Jianguo; Hosseini, Davood; Kierzkowska, Agnieszka M; Imtiaz, Qasim; Broda, Marcin; Müller, Christoph R

    2015-11-01

    We propose a new class of autothermal CO2 -capture process that relies on the integration of chemical looping combustion (CLC) into calcium looping (CaL). In the new process, the heat released during the oxidation of a reduced metallic oxide is utilized to drive the endothermic calcination of CaCO3 (the regeneration step in CaL). Such a process is potentially very attractive (both economically and technically) as it can be applied to a variety of oxygen carriers and CaO is not in direct contact with coal (and the impurities associated with it) in the calciner (regeneration step). To demonstrate the practical feasibility of the process, we developed a low-cost, steel-slag-based, Fe-functionalized CO2 sorbent. Using this material, we confirm experimentally the feasibility to heat-integrate CaCO3 calcination with a Fe(II)/Fe(III) redox cycle (with regards to the heat of reaction and kinetics). The autothermal calcination of CaCO3 could be achieved for a material that contained a Ca/Fe ratio of 5:4. The uniform distribution of Ca and Fe in a solid matrix provides excellent heat transfer characteristics. The cyclic CO2 uptake and redox stability of the material is good, but there is room for further improvement. PMID:26616682

  12. A study of some aspects of gas-slag-metal interactions : Towards dynamic process model and control

    OpenAIRE

    Ek, Mattias

    2012-01-01

    The present thesis deals with the development of a new type of dynamic model for metallurgical reactors. It also covers some of the theoretical aspects of steelmaking that is necessary to include in such an application. The thesis consists of modeling work, high temperature experiments and cold model experiments. Two different aspects of slags in the oxygen steelmaking were investigated. In the first study, slag samples were equilibrated with copper at 1923K in order to study their capacities...

  13. Effect of Na3PO4 on the Hydration Process of Alkali-Activated Blast Furnace Slag

    Directory of Open Access Journals (Sweden)

    Lukáš Kalina

    2016-05-01

    Full Text Available In recent years, the utilization of different non-traditional cements and composites has been increasing. Alkali-activated cementitious materials, especially those based on the alkali activation of blast furnace slag, have considerable potential for utilization in the building industry. However, alkali-slag cements exhibit very rapid setting times, which are too short in some circumstances, and these materials cannot be used for some applications. Therefore, it is necessary to find a suitable retarding admixture. It was shown that the sodium phosphate additive has a strong effect on the heat evolution during alkali activation and effectively retards the hydration reaction of alkali-activated blast furnace slag. The aim of the work is the suggestion of a reaction mechanism of retardation mainly based on Raman and X‑ray photoelectron spectroscopy.

  14. Influence of the activator concentration on the kinetics of the alkaline activation process of a blast furnace slag

    OpenAIRE

    Fernández-Jiménez, A.; Puertas, F.

    1997-01-01

    The influence of activator solution concentration on hydration kinetics of an alkaline activated blast furnace slag has been studied. The alkaline activator used was a mix of waterglass (Na2SiO3∙nH2O) and NaOH solution (of variable concentration). Final activator concentrations were 3,4 and 5 % Na2O wt. with respect to the slag total weight. Degree of reaction (α) was determined from hydration hea...

  15. Activities of chromium oxides in slag in the process of argon-oxygen refining of corrosion-resistant steel

    International Nuclear Information System (INIS)

    On the basis of computer simulation results and available experimental data the behaviour of chromium oxides on stainless steel refining is studied. It is revealed that during melting and argon-oxygen refining of stainless steels chromium oxides occur in the solution if the slag contains not more than 25% (by mass) Cr2O3; this fact generates a need for accounting chromium oxide activity in thermodynamic calculations. An increase of Cr2O3 activity in the slag of this type results in increasing percentage ratio of chromium and carbon in the metal

  16. Influence of electro slag remelting (esr) slags on remelted tool steel

    International Nuclear Information System (INIS)

    CaF/sub 2/ base synthetic slag is used during the electroslag remelting technique. ESR slags are refining components of steel. They are usually ionic conductors and in the liquid state conduct electrical current due to mobility of the ions. Physical properties of the slag such as electrical conductivity, viscosity, melting point, density, surface tension and chemical stability at operating temperature influence the removal of inclusions from the metal and subsequent chemical composition of the alloy. Three different type of molten slags system were used in the ESR process to produce different grades of tool steel. It was concluded that the selected lumps of fluorspar (CaF/sub 2/=98%) can be prefused to decrease the level of impurities and can be used in combination with other three-component slag to achieve the similar properties of end product as in the case of imported CaF/sub 2/ base slag. (author)

  17. Research on Hydration of Steel Slag Cement Activated with Waterglass

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper studied the hydration and strength influence factors of Steel Slag Cement (SSC),such as the quantity of steel slag and slag and the dosage of additive.The results show that:(a) In the process of hydration of SSC,steel slag and slag activate each other;(b) Waterglass's structure forms the preliminary skeleton of SSC,and the hydration products of SSC link or fill in the skeleton;(c) Sodium in waterglass is the catalytic and its concentration does not change in the process of hydration.(d) Structure of activation is a significant factor to the property of SSC.

  18. Influence of the activator concentration on the kinetics of the alkaline activation process of a blast furnace slag

    Directory of Open Access Journals (Sweden)

    Fernández-Jiménez, A.

    1997-06-01

    Full Text Available The influence of activator solution concentration on hydration kinetics of an alkaline activated blast furnace slag has been studied. The alkaline activator used was a mix of waterglass (Na2SiO3∙nH2O and NaOH solution (of variable concentration. Final activator concentrations were 3,4 and 5 % Na2O wt. with respect to the slag total weight. Degree of reaction (α was determined from hydration heat values obtained through isothermal conduction calorimetry. From the results obtained it is deduced that a treshold value of 4 % Na2O wt. exists. For those concentrations and at test temperatures (except for 25ºC and 3 % Na2O wt., the mechanism controlling hydration reaction for a values higher than 0.5, is a diffusion process. This process is described by .Jander equation [D3=(1-(1-α1/32=(k/r2t=0,0426(t/t0,5]. The activation energy obtained for that process is of approximately 50-58 Kj/mol.

    Se ha estudiado la influencia de la concentración de la disolución activante en la cinética de hidratación de una escoria granulada de alto horno, activada alcalinamente a distintas temperaturas. El activador alcalino utilizado fue una mezcla de water glass (Na2SiO3∙nH2O con una disolución de NaOH (de concentración variable. Las concentraciones finales del activador alcalino fueron: 3, 4 y 5 % en peso de Na2O respecto a la masa total de escoria. El grado de reacción (α se determinó a partir de valores de calor de hidratación obtenidos por calorimetría de conducción isotérmica. De los resultados obtenidos se deduce que existe un valor umbral de concentraciones en torno al 4 % en peso de Na2O. También para dichas concentraciones y a las temperaturas de ensayo (excepto a 25ºC con un 3 % en peso de Na2O, el mecanismo que controla la reacción de hidrataci

  19. Glassy slags for minimum additive waste stabilization

    International Nuclear Information System (INIS)

    Glassy slag waste forms are being developed to complement glass waste forms in implementing Minimum Additive Waste Stabilization (MAWS) for supporting DOE's environmental restoration efforts. The glassy slag waste form is composed of various crystalline and metal oxide phases embedded in a silicate glass phase. The MAWS approach was adopted by blending multiple waste streams to achieve up to 100% waste loadings. The crystalline phases, such as spinels, are very durable and contain hazardous and radioactive elements in their lattice structures. These crystalline phases may account for up to 80% of the total volume of slags having over 80% metal loading. The structural bond strength model was used to quantify the correlation between glassy slag composition and chemical durability so that optimized slag compositions were obtained with limited crucible melting and testing. Slag compositions developed through crucible melts were also successfully generated in a pilot-scale Retech plasma centrifugal furnace at Ukiah, California. Utilization of glassy slag waste forms allows the MAWS approach to be applied to a much wider range of waste streams than glass waste forms. The initial work at ANL has indicated that glassy slags are good final waste forms because of (1) their high chemical durability; (2) their ability to incorporate large amounts of metal oxides; (3) their ability to incorporate waste streams having low contents of flux components; (4) their less stringent requirements on processing parameters, compared to glass waste forms; and (5) their low requirements for purchased additives, which means greater waste volume reduction and treatment cost savings

  20. Comparison of possibilities the blast furnace and cupola slag utilization by concrete production

    OpenAIRE

    D. Baricová; A. Pribulová; P. Demeter

    2010-01-01

    In process of pig iron and cast iron production secondary raw materials and industrial wastes are formed The most abundant secondaryproduct originating in these processes are furnace slag. Blast furnace slag and cupola furnace slag originates from melting of gangue parts of metal bearing materials, slag forming additions and coke ash. In general, slag are compounds of oxides of metallic and non-metallic elements, which form chemical compounds and solutions with each other and also contain sma...

  1. Occurrence and speciation of copper in slags obtained during the pyrometallurgical processing of chalcopyrite concentrates at the Huelva smelter (Spain

    Directory of Open Access Journals (Sweden)

    Fernández-Caliani J.C.

    2012-01-01

    Full Text Available Slags involved in smelting-converting-refining operations to produce blister copper at the Atlantic Copper smelter, in Huelva (Spain, have been investigated by quantitative electron microprobe analysis, X-ray diffraction and digital imaging techniques. The results showed that mechanically entrapped matte particles are the dominant copper losses in the slags. The largest proportion of Cubearing particles (2.0-3.5 vol % is present in the magnetite-rich converter slags, due to the negative effect of viscosity on coalescence and precipitation of copper matte during conversion. They consist of high-grade matte particles with a core of copper metal rimmed by a copper sulfide phase (Cu2S. The mechanical entrainment of copper matte by slags from both the flash and electric furnaces resulted in copper losses accounting for less than 1.5 vol %, mostly occurring as tiny particles with a stoichiometric composition close to that of bornite (Cu5FeS4. Copper was not found to be enriched in fayalite and magnetite as solid solution.

  2. Uranium recovery from slags of metallic uranium

    International Nuclear Information System (INIS)

    The Center of the Nuclear Fuel of the Institute of Nuclear Energy Research - IPEN finished the program of attainment of fuel development for research reactors the base of Uranium Scilicet (U3 Si2) from Hexafluoride of Uranium (UF6) with enrichment 20% in weight of 235U. In the process of attainment of the league of U 3 Si 2 we have as Uranium intermediate product the metallic one whose attainment generates a slag contend Uranium. The present work shows the results gotten in the process of recovery of Uranium in slags of calcined slags of Uranium metallic. Uranium the metallic one is unstable, pyrophoricity and extremely reactive, whereas the U3O8 is a steady oxide of low chemical reactivity, what it justifies the process of calcination of slags of Uranium metallic. The calcination of the Uranium slag of the metallic one in oxygen presence reduces Uranium metallic the U3O8. Experiments had been developed varying it of acid for Uranium control and excess, nitric molar concentration gram with regard to the stoichiometric leaching reaction of temperature of the leaching process. The 96,0% income proves the viability of the recovery process of slags of Uranium metallic, adopting it previous calcination of these slags in nitric way with low acid concentration and low temperature of leaching. (author)

  3. Separation of Iron Droplets From Titania Bearing Slag

    Institute of Scientific and Technical Information of China (English)

    WANG Ming-yu; LOU Tai-ping; ZHANG Li; SUI Zhi-tong

    2008-01-01

    Owing to smelting vanadium-titanium magnetite ore, the amount of iron entrainment in slag as droplets is far higher than that in conventional BF slag. However, the iron droplets can be easily settled by blowing air into the molten slag. The results show that more than 80% of iron droplets in titania bearing slag can be settled and separated after treatment. The temperature rise of molten slag during the oxidizing process and the decreased viscosity caused by the component change of slag as well as air stirring in slag both accelerate the iron droplets settling. The vanadium content in the settled iron droplets and the original iron droplets was obtained by chemical analysis. The possible reason for the increased vanadium in the settled iron droplets was discussed by thermodynamic principles.

  4. 电石渣在电镀废水处理中的应用%Carbide Slag in Electroplating Waste Water Processing Application

    Institute of Scientific and Technical Information of China (English)

    潘燕锋

    2012-01-01

    文章介绍了一种以废治废的新工艺,该工艺利用电石渣代替烧碱作为中和沉淀剂处理电镀废水,不仅可以节约处理成本,而且使电石渣得到了综合利用,减轻环境污染,达到"以废治废"的目的,环境效益及经济效益显著。%The paper introduced a new technology of treating waste by waste,the process utilized the electric stone slag instead of caustic soda as precipitation agent in electroplating wastewater treatment,not only can save the cost of processing,and the comprehensive utilization of carbide slag by,reduce environmental pollution,to achieve the purpose of treating waste by waste,environmental benefits and economic benefits significantly.

  5. Characteristics and environmental aspects of slag: A review

    International Nuclear Information System (INIS)

    Highlights: • Summarize mineralogy and geochemistry of ferrous and non-ferrous slags. • Discuss potential environmental issues related to weathering of slag dumps. • Outline construction, secondary metal recovery, and environmental applications. • Compiled results from over 150 published studies on slag and included own data. - Abstract: Slag is a waste product from the pyrometallurgical processing of various ores. Based on over 150 published studies, this paper provides an overview of mineralogical and geochemical characteristics of different types of slag and their environmental consequences, particularly from the release of potentially toxic elements to water. This chapter reviews the characteristics of both ferrous (steel and blast furnace Fe) and non-ferrous (Ag, Cu, Ni, Pb, Sn, Zn) slag. Interest in slag has been increasing steadily as large volumes, on the order of hundreds of millions of tonnes, are produced annually worldwide. Research on slag generally focuses on potential environmental issues related to the weathering of slag dumps or on its utility as a construction material or reprocessing for secondary metal recovery. The chemistry and mineralogy of slag depend on the metallurgical processes that create the material and will influence its fate as waste or as a reusable product. The composition of ferrous slag is dominated by Ca and Si. Steel slag may contain significant Fe, whereas Mg and Al may be significant in Fe slag. Calcium-rich olivine-group silicates, melilite-group silicates that contain Al or Mg, Ca-rich glass, and oxides are the most commonly reported major phases in ferrous slag. Calcite and trace amounts of a variety of sulfides, intermetallic compounds, and pure metals are typically also present. The composition of non-ferrous slag, most commonly from base-metal production, is dominated by Fe and Si with significant but lesser amounts of Al and Ca. Silicates in the olivine, pyroxene, and melilite groups, as well as glass, spinels

  6. Influence of amount of oxidizing slag discharged from stainless steelmaking process of electric arc furnace on elution behavior into fresh water

    International Nuclear Information System (INIS)

    Fundamental study was carried out for provision for acidification of soil due to acid rain. The influence of weight of the additive slag on elution behavior of the slag into water was studied in this study. Elution experiment was carried out on a basis of JIS K 0058-1. Generally, the pH in the aqueous solution increased with an increase in weight of the additive slag. The pH converged to approximately eight. Calcium, magnesium and manganese, which were essential elements for plants, were eluted from the slag irrespective to elution condition. The eluted concentrations of Ca and Mg increased with an increase in weight of the additive slag. Silicon and zinc were also eluted depending on the conditions. Aluminum that was harmful for plants was not eluted from the used slag.

  7. Influence of amount of oxidizing slag discharged from stainless steelmaking process of electric arc furnace on elution behavior into fresh water

    Science.gov (United States)

    Yokoyama, S.; Shimomura, T.; Hisyamudin, M. N. N.; Takahashi, T.; Izaki, M.

    2012-03-01

    Fundamental study was carried out for provision for acidification of soil due to acid rain. The influence of weight of the additive slag on elution behavior of the slag into water was studied in this study. Elution experiment was carried out on a basis of JIS K 0058-1. Generally, the pH in the aqueous solution increased with an increase in weight of the additive slag. The pH converged to approximately eight. Calcium, magnesium and manganese, which were essential elements for plants, were eluted from the slag irrespective to elution condition. The eluted concentrations of Ca and Mg increased with an increase in weight of the additive slag. Silicon and zinc were also eluted depending on the conditions. Aluminum that was harmful for plants was not eluted from the used slag.

  8. Energy effective approach for activation of metallurgical slag

    Science.gov (United States)

    Mazov, I. N.; Khaydarov, B. B.; Mamulat, S. L.; Suvorov, D. S.; Saltikova, Y. S.; Yudin, A. G.; Kuznetsov, D. V.

    2016-01-01

    The paper presents results of investigation of the process of mechanical activation of metallurgical slag using different approaches - ball milling and electromagnetic vortex apparatus. Particle size distribution and structure of mechanically activated slag samples were investigated, as well as energetic parameters of the activation process. It was shown that electromagnetic vortex activation is more energy effective and allows to produce microscale milled slag-based concrete using very short treatment time. Activated slag materials can be used as clinker-free cement in civilian and road construction, providing ecology-friendly technology and recycling of high-tonnage industrial waste.

  9. Crystallization phenomena in slags

    Science.gov (United States)

    Orrling, Carl Folke

    2000-09-01

    The crystallization of the mold slag affects both the heat transfer and the lubrication between the mold and the strand in continuous casting of steel. In order for mold slag design to become an engineering science rather than an empirical exercise, a fundamental understanding of the melting and solidification behavior of a slag must be developed. Thus it is necessary to be able to quantify the phenomena that occur under the thermal conditions that are found in the mold of a continuous caster. The double hot thermocouple technique (DHTT) and the Confocal Laser Scanning Microscope used in this study are two novel techniques for investigating melting and solidification phenomena of transparent slags. Results from these techniques are useful in defining the phenomena that occur when the slag film infiltrates between the mold and the shell of the casting. TTT diagrams were obtained for various slags and indicated that the onset of crystallization is a function of cooling rate and slag chemistry. Crystal morphology was found to be dependent upon the experimental temperature and four different morphologies were classified based upon the degree of melt undercooling. Continuous cooling experiments were carried out to develop CCT diagrams and it was found that the amount and appearance of the crystalline fraction greatly depends on the cooling conditions. The DHTT can also be used to mimic the cooling profile encountered by the slag in the mold of a continuous caster. In this differential cooling mode (DCT), it was found that the details of the cooling rate determine the actual response of the slag to a thermal gradient and small changes can lead to significantly different results. Crystal growth rates were measured and found to be in the range between 0.11 mum/s to 11.73 mum/s depending on temperature and slag chemistry. Alumina particles were found to be effective innoculants in oxide melts reducing the incubation time for the onset of crystallization and also extending

  10. Critical Evaluation of Prediction Models for Phosphorus Partition between CaO-based Slags and Iron-based Melts during Dephosphorization Processes

    Science.gov (United States)

    Yang, Xue-Min; Li, Jin-Yan; Chai, Guo-Ming; Duan, Dong-Ping; Zhang, Jian

    2016-08-01

    According to the experimental results of hot metal dephosphorization by CaO-based slags at a commercial-scale hot metal pretreatment station, the collected 16 models of equilibrium quotient k_{{P}} or phosphorus partition L_{{P}} between CaO-based slags and iron-based melts from the literature have been evaluated. The collected 16 models for predicting equilibrium quotient k_{{P}} can be transferred to predict phosphorus partition L_{{P}} . The predicted results by the collected 16 models cannot be applied to be criteria for evaluating k_{{P}} or L_{{P}} due to various forms or definitions of k_{{P}} or L_{{P}} . Thus, the measured phosphorus content [pct P] in a hot metal bath at the end point of the dephosphorization pretreatment process is applied to be the fixed criteria for evaluating the collected 16 models. The collected 16 models can be described in the form of linear functions as y = c0 + c1 x , in which independent variable x represents the chemical composition of slags, intercept c0 including the constant term depicts the temperature effect and other unmentioned or acquiescent thermodynamic factors, and slope c1 is regressed by the experimental results of k_{{P}} or L_{{P}} . Thus, a general approach to developing the thermodynamic model for predicting equilibrium quotient k_{{P}} or phosphorus partition L P or [pct P] in iron-based melts during the dephosphorization process is proposed by revising the constant term in intercept c0 for the summarized 15 models except for Suito's model (M3). The better models with an ideal revising possibility or flexibility among the collected 16 models have been selected and recommended. Compared with the predicted result by the revised 15 models and Suito's model (M3), the developed IMCT- L_{{P}} model coupled with the proposed dephosphorization mechanism by the present authors can be applied to accurately predict phosphorus partition L_{{P}} with the lowest mean deviation δ_{{L_{{P}} }} of log L_{{P}} as 2.33, as

  11. Radionuclides in steel slag intended for road construction

    International Nuclear Information System (INIS)

    The objective of this study was to describe the radiochemical characteristics of electric arc furnace (EAF) slag from Croatian EAF black steel slags, generated from carbon steel production process in CMC Sisak d.o.o., and steel mill in Split in order to enhance the understanding of possibilities for their use in road construction. This article presents the results of radionuclide in electric arc furnace steel slag. The presence of natural isotopes 40K, 232Th (228Ra), 226Ra and 238U was established. The measured activity in slag natural isotopes lies within the Croatian legally permitted limits. (author)

  12. Chemical, Mineralogical, and Morphological Properties of Steel Slag

    Directory of Open Access Journals (Sweden)

    Irem Zeynep Yildirim

    2011-01-01

    Full Text Available Steel slag is a byproduct of the steelmaking and steel refining processes. This paper provides an overview of the different types of steel slag that are generated from basic-oxygen-furnace (BOF steelmaking, electric-arc-furnace (EAF steelmaking, and ladle-furnace steel refining processes. The mineralogical and morphological properties of BOF and electric-arc-furnace-ladle [EAF(L] slag samples generated from two steel plants in Indiana were determined through X-Ray Diffraction (XRD analyses and Scanning Electron Microscopy (SEM studies. The XRD patterns of both BOF and EAF(L slag samples were very complex, with several overlapping peaks resulting from the many minerals present in these samples. The XRD analyses indicated the presence of free MgO and CaO in both the BOF and EAF(L slag samples. SEM micrographs showed that the majority of the sand-size steel slag particles had subangular to angular shapes. Very rough surface textures with distinct crystal structures were observed on the sand-size particles of BOF and EAF(L slag samples under SEM. The characteristics of the steel slag samples considered in this study are discussed in the context of a detailed review of steel slag properties.

  13. Decalcification resistance of alkali-activated slag

    Energy Technology Data Exchange (ETDEWEB)

    Komljenovic, Miroslav M., E-mail: miroslav.komljenovic@imsi.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia); Bascarevic, Zvezdana, E-mail: zvezdana@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia); Marjanovic, Natasa, E-mail: natasa@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia); Nikolic, Violeta, E-mail: violeta@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia)

    2012-09-30

    Highlights: Black-Right-Pointing-Pointer The effects of decalcification on properties of alkali-activated slag were studied. Black-Right-Pointing-Pointer Decalcification was performed by concentrated NH{sub 4}NO{sub 3} solution (accelerated test). Black-Right-Pointing-Pointer Portland-slag cement (CEM II/A-S 42.5 N) was used as a benchmark material. Black-Right-Pointing-Pointer Decalcification led to strength decrease and noticeable structural changes. Black-Right-Pointing-Pointer Alkali-activated slag showed significantly higher resistance to decalcification. - Abstract: This paper analyses the effects of decalcification in concentrated 6 M NH{sub 4}NO{sub 3} solution on mechanical and microstructural properties of alkali-activated slag (AAS). Portland-slag cement (CEM II/A-S 42.5 N) was used as a benchmark material. Decalcification process led to a decrease in strength, both in AAS and in CEM II, and this effect was more pronounced in CEM II. The decrease in strength was explicitly related to the decrease in Ca/Si atomic ratio of C-S-H gel. A very low ratio of Ca/Si {approx}0.3 in AAS was the consequence of coexistence of C-S-H(I) gel and silica gel. During decalcification of AAS almost complete leaching of sodium and tetrahedral aluminum from C-S-H(I) gel also took place. AAS showed significantly higher resistance to decalcification in relation to the benchmark CEM II due to the absence of portlandite, high level of polymerization of silicate chains, low level of aluminum for silicon substitution in the structure of C-S-H(I), and the formation of protective layer of polymerized silica gel during decalcification process. In stabilization/solidification processes alkali-activated slag represents a more promising solution than Portland-slag cement due to significantly higher resistance to decalcification.

  14. Skid resistance performance of asphalt wearing courses with electric arc furnace slag aggregates.

    Science.gov (United States)

    Kehagia, Fotini

    2009-05-01

    Metallurgical slags are by-products of the iron and steel industry and are subdivided into blast furnace slag and steel slag according to the different steel-producing processes. In Greece, slags are mostly produced from steelmaking using the electric arc furnace process, and subsequently are either disposed in a random way or utilized by the cement industry. Steel slag has been recently used, worldwide, as hard aggregates in wearing courses in order to improve the skidding resistance of asphalt pavements. At the Highway Laboratory, Department of Civil Engineering of Aristotle University of Thessaloniki research has been carried out in the field of steel slags, and especially in electric arc furnace (EAF) slag, to evaluate their possible use in highway engineering. In this paper, the recent results of anti-skidding performance of steel slag aggregates in highway pavements are presented. PMID:19423603

  15. Effect of Slag Thickness on Macrosegregation and Transition Zone Width of Electroslag Remelting Dual Alloy Ingot

    Science.gov (United States)

    Wang, Qiang; Yan, Hongguang; Ren, Neng; Li, Baokuan

    2016-01-01

    The influence of the slag thickness on macrosegregation and transition zone (TZ) width of electroslag remelting (ESR) dual alloy ingot was investigated. To produce a dual alloy ingot, an electrode, constituted by a CrMoV bar and a NiCrMoV alloy bar, was remelted by using the ESR process. The slag thickness ranged from 50 mm to 70 mm. The results indicate that the slag temperature and melt rate first increase and then decrease with the increasing of the slag thickness. The metal sump depth, however, monotonically decreases. The most pronounced macrosegregation is found when the slag thickness is 50 mm and is alleviated with a thicker slag. The minimal TZ width appears when the slag thickness is 60 mm. Processing the ESR dual alloy ingot with a 60-mm slag layer is the best choice for reducing the TZ width and macrosegregation in the present work.

  16. Steel desulphurization with synthetic slag

    Directory of Open Access Journals (Sweden)

    Heput, T.

    2007-02-01

    Full Text Available Generally speaking, sulphur is considered a harmful element for steel quality, reason why all the technological steps are being taken in order to eliminate it from the metal bath. This paper deals with the influence of the chemical composition, on the slag quantity and of the bath stirring condition upon the desulphurization process in the casting ladle by treatment with synthetic slag. The experiments were made at an open-hearth plant with the steel tapping in two ladles (the desulphurization was made with synthetic slag at one ladle while the other one was considered standard and at the electric steel plant and for the synthetic slag formation a mix was used, made, according to several receipts, of: lime (50-75%, fluorine (0-17%, bauxite (0-32% and aluminous slag (8-22%. The data were processed in the calculation programs EXCEL and MATLAB, which resulted in a series of correlations between the desulphurization degree and the chemical composition of the slag, respectively the slag quantity both for the charges bubbled with Argon and the unbubbled ones.

    En general, el azufre es considerado un elemento nocivo para la calidad del acero y, por eso, en la práctica, se toman todas las medidas de orden tecnológico para su eliminación del baño metálico. En este trabajo se analiza la influencia de la composición química, de la cantidad de escoria y del estado de agitación del baño sobre el proceso de desulfuración en la cuchara para fundir por tratamiento con escoria sintética. Los experimentos se han realizado en una acería evacuando el acero en dos ollas (en una cuchara se efectuó la desulfuración con escoria sintética y a la otra se consideró como patrón y en un acería eléctrica y para la formación de la escoria sintética se utilizó una mezcla producida según muchas recetas, formada por: cal (50-75%, fluorina (0-17%, bauxita (0-32% y escoria aluminosa (8-22%. Los datos han sido procesados en los programas de c

  17. Accelerated mineral carbonation of stainless steel slags for CO2 storage and waste valorization: effect of process parameters on geochemical properties

    OpenAIRE

    Santos, Rafael; Van Bouwel, Jens; Vandevelde, Ellen; Mertens, Gilles; Elsen, Jan; Van Gerven, Tom

    2013-01-01

    This work explores the mineral carbonation of stainless steel slags in search for a technically and economically feasible treatment solution that steers these waste residues away from costly disposal in landfills and into valuable applications. Argon Oxygen Decarburization (AOD) and Continuous Casting (CC) slags prove ideal for mineral carbonation as their powdery morphology forgoes the need for milling and provides sufficient surface area for high reactivity towards direct aqueous carbonatio...

  18. Microstructure characterisation of freeze linings formed in a copper slag cleaning slag

    Directory of Open Access Journals (Sweden)

    Jansson J.

    2015-01-01

    Full Text Available The initial growth rate of freeze linings on water-cooled elements submerged in molten iron silicate slag is fast. The freeze lining microstructure forming on water cooled steel surface in a high-silica, slag cleaning furnace slag of a direct-to-blister copper smelter is mostly glassy or amorphous. It contains 5-30 μm magnetite crystals, very small and larger copper droplets as well as small magnetite and silicate nuclei embedded in the glassy silica-rich matrix. Chemically the formed freeze linings are more silica-rich than the slag from which they were generated. Magnetite (spinel is the primary phase of the solidifying SCF slag but it does not form a continuous network through the freeze lining. Its strength is given by the intergranular silica-rich phase which initially is glassy or microcrystalline. Due to only partial slag reduction in the SCF process, large magnetite crystals are present in the freeze lining and seem to interact physically with copper droplets.

  19. Steelmaking slag beneficiation by magnetic separator and impacts on sinter quality

    Directory of Open Access Journals (Sweden)

    Bölükbaşı Ö.S.

    2014-01-01

    Full Text Available Basic oxygen furnaces (BOF slag is the main problem at all iron and steel factories. About more than 6 million tons/year of BOF slag has been accumulated from the waste stockyards in Turkey. Dumps slags can be revaluated by a processing technology which makes it possible to obtain products that meet the requirements of sintering and blast furnace production. The slags with particle size of -10 mm were enriched by the magnetic separator resulting and increase in Fe grade from 18% to 33%. The use of BOF slag in sinter blend provided additional Mn, CaO, MgO and introduced a good solution to environmental problems.

  20. The enhancement effect of pre-reduction using zero-valent iron on the solidification of chromite ore processing residue by blast furnace slag and calcium hydroxide.

    Science.gov (United States)

    Li, Jinchunzi; Chen, Zhonglin; Shen, Jimin; Wang, Binyuan; Fan, Leitao

    2015-09-01

    A bench scale study was performed to assess the effectiveness of the solidification of chromite ore processing residue (COPR) by blast furnace slag and calcium hydroxide, and investigate the enhancement effect of pre-reduction using zero-valent iron (ZVI) on the solidification treatment. The degree of Cr immobilization was evaluated using the Toxicity Characteristic Leaching Procedure (TCLP) as well as the solid waste-extraction procedure for leaching toxicity-sulfuric acid & nitric acid method (Chinese standard HJ/T299-2007). Strength tests and semi-dynamic leaching tests were implemented to investigate the potential for reusing the final treatment product as a readily available construction material. The experimental results showed that the performance of pre-reduction/solidification (S/S) was superior to that of solidification alone. After pre-reduction, all of the S/S treated COPR samples met the TCLP limit for total Cr (5 mg L(-1)), whereas the samples with a COPR content below 40% met the pollution control limit of bricks and building block products (Chinese standard HJ/T 301-2007) produced with COPR for total Cr (0.3 mg L(-1)). At the same time, all of the S/S treated specimens tested were suitable for utilization at certain levels. PMID:25929874

  1. [Solidification/Stabilization of Chromite Ore Processing Residue (COPR) Using Zero-Valent Iron and Lime-Activated Ground Granulated Blast Furnace Slag].

    Science.gov (United States)

    Chen, Zhong-lin; Li, Jin-chunzi; Wang, Bin-yuan; Fan, Lei-tao; Shen, Ji-min

    2015-08-01

    The solidification/stabilization (S/S) of chromite ore processing residue (COPR) was performed using zero-valent iron (ZVI) and lime-activated ground granulated blast furnace slag (GGBFS). The degree of Cr immobilization was evaluated using the leaching procedure, mineral composition analysis and morphology analysis. Semi-dynamic leaching tests were implemented to investigate the potential for reusing the final treatment product as a readily available construction material. The results showed that after reduction, all of the S/S treated COPR samples met the pollution control limit of bricks and building block products (Chinese standard HJ/T 301-2007) produced with COPR for total Cr (0.3 mg x L(-1)), the compressive strength of all the S/S samples could meet the compressive strength standard (15 MPa) for producing clay bricks, and Cr existed as the specie that bound to Fe/Mn oxides in the S/S samples. At the same time, all of the S/S treated specimens tested were suitable for utilization at certain levels. PMID:26592036

  2. 熔融钒渣直接氧化钠化提钒新工艺研究%A New Process for Vanadium Extraction from Molten Vanadium Slag by Direct Oxidation and Sodium Activating Method

    Institute of Scientific and Technical Information of China (English)

    宋文臣; 李宏

    2012-01-01

    To address the problem of heat waste of vanadium slag in the existing vanadium extraction process, a new process is proposed in this paper to extract vanadium from molten vanadium slag by direct oxidation and sodium activating method. On the basis of current vanadium extraction process, the new process was verified by thermodynamic and kinetic calculation and analysis, and then simulation tests were carried out in the laboratory. The results show that with enough heat, vanadium slag can be kept in molten state during the vanadium extraction process. The dynamic conditions of the new process are noticeably better than the existing process. The oxidization rate of vanadium slag is about 90% and vanadium leaching rate can reach 82% or above with enough oxygen and Na2CO3 content at 20% ~ 30% of vanadium slag' weight. Thus, the feasibility of the new process is confirmed by the results.%针对现行钒渣焙烧工艺中存在的钒渣高温物理热的浪费问题,提出“熔融钒渣直接氧化钠化提钒”新工艺.在现行工艺基础上,对新工艺进行了热力学和动力学的计算与分析,最后进行了新工艺的实验室模拟试验.研究结果表明:新工艺条件下,钒渣在反应过程中热量充足会保持良好的熔融状态;新工艺的动力学条件明显优越于现行工艺;实验室试验结果验证了新工艺的可行性,在供氧充足,Na2CO3用量为20%~30%的条件下,钒渣氧化率约为90%,钒浸出率在82%以上.

  3. Critical Assessment of P2O5 Activity Coefficients in CaO-based Slags during Dephosphorization Process of Iron-based Melts

    Science.gov (United States)

    Yang, Xue-min; Li, Jin-yan; Chai, Guo-Ming; Duan, Dong-ping; Zhang, Jian

    2016-08-01

    According to the experimental results of hot metal dephosphorization by CaO-based slags at a commercial-scale hot metal pretreatment station, activity a_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in the CaO-based slags has been determined using the calculated comprehensive mass action concentration N_{{{{Fe}}t {{O}}}}{} of iron oxides by the ion and molecule coexistence theory (IMCT) for representing the reaction ability of Fe t O, i.e., activity of a_{{{{Fe}}t {{O}}}}{} . The collected ten models from the literature for predicting activity coefficient γ_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in CaO-based slags have been evaluated based on the determined activity a_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 by the IMCT as the criterion. The collected ten models of activity coefficient γ_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in CaO-based slags can be described in the form of a linear function as log γ_{{{{P}}_{ 2} {{O}}_{ 5} }} ≡ y = c0 + c1 x , in which independent variable x represents the chemical composition of slags, intercept c0 including the constant term depicts temperature effect and other unmentioned or acquiescent thermodynamic factors, and slope c1 is regressed by the experimental results. Thus, a general approach for obtaining good prediction results of activity a_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in CaO-based slags is proposed by revising the constant term in intercept c0 for the collected ten models. The better models with an ideal revising possibility or flexibility in the collected ten models have been selected and recommended.

  4. A Blended Cement Containing Blast Furnace Slag and Phosphorous Slag

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Blended cement containing blast furnace slag(BFS) and phosphorous slag(PS) is a new kind of cement.The total content of blended materials could increase if two additives were used. Using the same admixtures, the properties of the blended cement with 70% additives could reach the standard of 525-grade slag cement according to GB.The strength of cement with 80% additives could reach the standard of 425-grade slag cement.The tests of strength, pore structure,hydration products,inhibiting alkali-aggregate reaction, resistance to sulfate corrosion of BFS-PSC were performed.

  5. Preparation of Slag Wool by Integrated Waste-Heat Recovery and Resource Recycling of Molten Blast Furnace Slags: From Fundamental to Industrial Application

    Directory of Open Access Journals (Sweden)

    Dawei Zhao

    2014-05-01

    Full Text Available The present paper investigated the process of the slag wool fabrication using high temperature blast furnace (BF slag modified by coal ash (CA. The liquidus temperature and viscosity of the slag system with different mass ratios of BF slag and CA were measured through an inner cylinder rotation method. The approximate mass ratio used to fabricate the slag wool was therefore determined and slag wool was then successfully prepared with a high-speed air injection method in the laboratory. The effect of mBF/m ratio, slag temperature for injection and air pressure on the preparation of slag wool was systematically investigated. The mechanical and thermal properties were also studied to confirm the long-term working conditions of the slag wool. An industry-scale slag wool production application was established. The energy consumption and the pollutant generation, were analyzed and compared with the traditional production method, which indicated a 70% reduction in energy consumption and a 90% pollution emission decrease.

  6. Selective Leaching of Germanium and Indium from Dezincification Oxidized Hard Zinc Slag with Oxygen Pressure Leaching Process%氧压酸浸法从脱锌氧化硬锌渣中选择性浸出锗和铟

    Institute of Scientific and Technical Information of China (English)

    王继民; 曹洪杨; 吴斌秀; 王坚; 吴成春; 李俊红

    2013-01-01

    以含锗、铟的锌精炼脱锌氧化硬锌渣为原料,采用氧压酸浸工艺选择性回收其中的锗和铟,并对锗、铟、铜、锡、锑等元素的溶出行为进行了研究.结果表明,锗、铟及锌溶出率分别达到95%、91%及98%以上,大部分铅、硅、锡、锑等则留于残渣中.%Germanium and indium are selective recovered from dezincification oxidized hard zinc slag with oxygen pressure leaching process. The dissolving performances of Ge, In, Cu, Sn, Sb were investigated. The results show that the dissolution rates of Ge, In and Zn from the hard zinc slag are up to 95%, 91% and 98% respectively, and most of Pb, Si, Sn and Sb stay in the trail slag.

  7. Slag recycling of irradiated vanadium

    International Nuclear Information System (INIS)

    An experimental inductoslag apparatus to recycle irradiated vanadium was fabricated and tested. An experimental electroslag apparatus was also used to test possible slags. The testing was carried out with slag materials that were fabricated along with impurity bearing vanadium samples. Results obtained include computer simulated thermochemical calculations and experimentally determined removal efficiencies of the transmutation impurities. Analyses of the samples before and after testing were carried out to determine if the slag did indeed remove the transmutation impurities from the irradiated vanadium

  8. Slag analysis with laser-induced breakdown spectrometry.

    Science.gov (United States)

    Kraushaar, M; Noll, R; Schmitz, H U

    2003-10-01

    Laser-induced breakdown spectrometry (LIBS) has been applied for multi-elemental analysis of slag samples from a steel plant. In order to avoid the time-consuming step of sample preparation, the liquid slag material can be filled in special probes. After cooling of the liquid slag and solidification, the samples can be analyzed with LIBS. Chemical analysis of slag is an essential input parameter used for numerical simulations to control liquid steel processing. The relative variation range of element concentrations in slag samples from steel production can amount to up to 30%. A multivariate calibration model is used to take into account matrix effects caused by these varying concentrations. By optimizing the measuring parameters as well as the calibration models, an agreement between the standard X-ray fluorescence (XRF) analysis and LIBS analysis in terms of the coefficient of determination r2 of 0.99 for the main analytes CaO, SiO2, and Fetot of converter slag samples was achieved. The average repeatability of the LIBS measurement for these elements in terms of the relative standard deviation of the determined concentration is improved to less than 1.0%. With these results, the basis is established for future on-line applications of LIBS in the steel-making industry for slag analysis. PMID:14639759

  9. Utilizing steel slag in environmental application - An overview

    Science.gov (United States)

    Lim, J. W.; Chew, L. H.; Choong, T. S. Y.; Tezara, C.; Yazdi, M. H.

    2016-06-01

    Steel slags are generated as waste material or byproduct every day from steel making industries.The potential environmental issues which are related with the slag dump or reprocessing for metal recovery are generally being focused in the research. However the chemistry and mineralogy of slag depends on metallurgical process which is able to determine whether the steel slag can be the reusable products or not. Nowadays, steel slag are well characterized by using several methods, such as X-ray Diffraction, ICP-OES, leaching test and many more. About the industrial application, it is mainly reused as aggregate for road construction, as armour stones for hydraulic engineering constructions and as fertilizers for agricultural purposes. To ensure the quality of steel slag for the end usage, several test methods are developed for evaluating the technical properties of steel slag, especially volume stability and environmental behaviour. In order to determine its environmental behaviour, leaching tests have been developed. The focus of this paper however is on those applications that directly affect environmental issues including remediation, and mitigation of activities that negatively impact the environment.

  10. UTILIZATION OF LIGHTWEIGHT MATERIALS MADE FROM COAL GASIFICATION SLAGS

    Energy Technology Data Exchange (ETDEWEB)

    Vas Choudhry; Stephen Kwan; Steven R. Hadley

    2001-07-01

    The objective of the project entitled ''Utilization of Lightweight Materials Made from Coal Gasification Slags'' was to demonstrate the technical and economic viability of manufacturing low-unit-weight products from coal gasification slags which can be used as substitutes for conventional lightweight and ultra-lightweight aggregates. In Phase I, the technology developed by Praxis to produce lightweight aggregates from slag (termed SLA) was applied to produce a large batch (10 tons) of expanded slag using pilot direct-fired rotary kilns and a fluidized bed calciner. The expanded products were characterized using basic characterization and application-oriented tests. Phase II involved the demonstration and evaluation of the use of expanded slag aggregates to produce a number of end-use applications including lightweight roof tiles, lightweight precast products (e.g., masonry blocks), structural concrete, insulating concrete, loose fill insulation, and as a substitute for expanded perlite and vermiculite in horticultural applications. Prototypes of these end-use applications were made and tested with the assistance of commercial manufacturers. Finally, the economics of expanded slag production was determined and compared with the alternative of slag disposal. Production of value-added products from SLA has a significant potential to enhance the overall gasification process economics, especially when the avoided costs of disposal are considered.

  11. Leaching modelling of slurry-phase carbonated steel slag.

    Science.gov (United States)

    Costa, G; Polettini, A; Pomi, R; Stramazzo, A

    2016-01-25

    In the present work the influence of accelerated mineral carbonation on the leaching behaviour of basic oxygen furnace steel slag was investigated. The environmental behaviour of the material as evaluated through the release of major elements and toxic metals under varying pH conditions was the main focus of the study. Geochemical modelling of the eluates was used to derive a theoretical description of the underlying leaching phenomena for the carbonated material as compared to the original slag. Among the investigated elements, Ca and Si were most appreciably affected by carbonation. A very clear effect of carbonation on leaching was observed for silicate phases, and lower-Ca/Si-ratio minerals were found to control leaching in carbonated slag eluates as compared to the corresponding untreated slag sample as a result of Ca depletion from the residual slag particles. Clear evidence was also gained of solubility control for Ca, Mg and Mn by a number of carbonate minerals, indicating a significant involvement of the original slag constituents in the carbonation process. The release of toxic metals (Zn, V, Cr, Mo) was found to be variously affected by carbonation, owing to different mechanisms including pH changes, dissolution/precipitation of carbonates as well as sorption onto reactive mineral surfaces. The leaching test results were used to derive further considerations on the expected metal release levels on the basis of specific assumptions on the relevant pH domains for the untreated and carbonated slag. PMID:26489916

  12. Phase composition of high lithium slags from the recycling of lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Elwert, Tobias; Goldmann, Daniel [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Lehrstuhl fuer Rohstoffaufbereitung und Recycling; Strauss, Karl; Schirmer, Thomas [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Lehrstuhl fuer Mineralogie, Geochemie und Salzlagerstaetten

    2012-05-15

    The phase composition of different lithium containing slags from the recycling of lithium ion batteries was investigated in this study. All slags originate from the pyro-metallurgical Umicore Battery Recycling Process which uses an Al{sub 2}O{sub 3}-CaO-Li{sub 2}O-MgO-(MnO)-SiO{sub 2} slag system. The main objective of this study was the determination of the chemical behavior of lithium depending on the slag composition to develop possible slag beneficiation processes for lithium recovery. Lithium aluminate was the main lithium bearing phase in all slag types. The aluminum rich slag has lithium nearly exclusively concentrated in lithium aluminate. If the slag system is shifted towards lower aluminum and higher silicon content additionally a lithium silicate can be found. In a manganese rich slag besides of the aluminate lithium containing spinel type oxides can be calculated. Additionally, the structure and texture of the slags reveal some interesting information about the phase formation during the cooling process. (orig.)

  13. Petrochemistry of coal ash slags. I. Formation of melilite and a high temperature glass from a calcium-rich, silica-deficient slag

    Energy Technology Data Exchange (ETDEWEB)

    Schobert, H.H.; Barbie, D.L.; Christensen, O.D.; Kerner, F.R.

    1977-01-01

    Pilot plant studies are being conducted of a fixed-bed slagging coal gasification process. Lignite from the Indianhead mine is reacted with steam and oxygen in a gasifier at hearth zone temperatures over 1650/sup 0/C. Slag samples were subjected to chemical and petrographic analysis. Layers of layered slag modules were analyzed; the inner layers contain abundant melilite while the outer core is a glass. Results show that the characteristics of the coal ash slag can be affected by temperature fluctuations in the gasifier hearth, and that chemical, flow, and heat transfer behavior are all susceptible to change as a result. 8 figs., 3 tables. (DLC)

  14. Hydration and properties of sodium sulfate activated slag

    OpenAIRE

    A.M. Rashad; Bai, Y.(Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China); Basheer, P. A. M.; Milestone, N.B.; Collier, N.C.

    2013-01-01

    Interest in alkali-activated slag as a construction material is increasing, primarily due to its environmentally friendly nature. Although strong alkaline activators, such as sodium hydroxide and sodium silicate solution, are preferred for high strength, none of them exists naturally and their manufacturing process is quite energy intensive. Whilst sodium sulfate (NaSO ) can be obtained from natural resources, the early strength of NaSO activated slag is usually low. In this paper, the effect...

  15. Characterization of structure and thermophysical properties of three ESR slags

    Science.gov (United States)

    Plotkowski, A.; deBarbadillo, J.; Krane, Matthew J. M.

    2016-07-01

    The structure and properties of electroslag remelting (ESR) slags were characterized. Slags samples of three compositions were obtained from industrial remelting processes at Special Metals Corporation and from casting in a laboratory vacuum induction melter. The structure of the slag samples was observed using optical and electron microscopy, and phases were identified and their relative amounts quantified using X-ray diffraction. Laser flash thermal diffusivity, density, and differential scanning calorimetry measurements for specific heat were performed to determine the bulk thermal conductivity of the samples. Sample porosity was measured as a function of depth using a serial sectioning technique, and a onedimensional computational model was developed to estimate the thermal conductivity of the fully dense slags. These results are discussed in context with previous studies, and opportunities for future research are identified. AFRL Case Number: 88ABW-2015-1871.

  16. The estimation of the reaction stimulators influence into the extraction slag conditions

    Directory of Open Access Journals (Sweden)

    A. W. Bydałek

    2010-04-01

    Full Text Available Slag stimulators was analysed used the DTA methods. In the paper a method of determining the reduction capability of slag solutions wasused. The analysis of slag stimulators concertinaing of the chloride and fluoride compositions are showed. There are the oxides complexesused in to the slag composition for the purpose to establish two indicators in reduction processes: EW - indicator showing the direction and intensity of reaction in to the slag composition, and r - indicator of the rate of coal consumption. There are possible and purposeful the construction optimization programme engaging all of the phisics chemical influence the slags in processes of melting metals alloys. The proposed results, ranges of areas on graphs of phase equilibria's, demonstrative on the optimum values, will be verified in laboratory conditions and industrial. The initiation the new data the gathered base will be built in system of open base enabling.

  17. Red thermoluminescence of quartz and its application in dating archaeometallurgical slag.

    Science.gov (United States)

    Haustein, M; Krbetschek, M R

    2002-01-01

    Slag is often the only relic of early pyrometallurgical processes. In archaeological research information about the age of slag deposits is needed and diflicult to obtain with traditional methods. Thermoluminescence has a great potential in this field, because the smelting process leads to a well defined resetting of the 'Luminescence Clock'. Metallurgical slag generally consists of many components, artificial secondary minerals, e.g. fayalite and glass phases usually being the dominant parts. Primary minerals, called relics, are also components or slag. Such a complex composition leads to large difficulties in palaeodose determation if the bulk slag is used. To overcome these problems defined phases of the slag have been separated. Palaeodose determination has been carried out on separated quartz fractions by 'Single Aliquot Regeneration' procedures using the 620 nm emission. The dose rate was determined by high-resolution gamma spectrometry. Alpha autoradiography was carried out to get information about the distribution of radionuclides. The study includes first dating results. PMID:12382771

  18. Reclamation and reuse of MWI slags under the aspect of ground water protection

    International Nuclear Information System (INIS)

    Some importants aspects of ground water protection are discussed, with regard to MWI-slag reclamation and reuse as construction material. The effects of a treatment process on residual organic compounds of slag material have to be regarded as very positive. Directed chemical influencing of the hydratation process directly after incineration offers new perspectives for generating slag with potentially little and constant elution behaviour. The authors welcome the new, sharpened demands on reuse of MWI-slag in Northrhine-Westfalia. This challenge can be met by the proposed treatment procedure without problems. (orig.)

  19. Stabilization of basic oxygen furnace slag by hot-stage carbonation treatment

    OpenAIRE

    Santos, Rafael; Ling, Da; Sarvaramini, Amin; Guo, Muxing; Elsen, Jan; Larachi, Faïçal; Beaudoin, Georges; Blanpain, Bart; Van Gerven, Tom

    2012-01-01

    Treatment and disposal of Basic Oxygen Furnace (BOF) slag, a residue of the steel production process characterized by high basicity and propensity for heavy metal leaching, is a costly burden on metallurgical plants; a sustainable valorization route is desired. The stabilization of BOF slag utilizing hot-stage carbonation treatment was investigated; this approach envisions carbonation during the hot-to-cold pathway followed by the material after the molten slag is poured and solidified. Three...

  20. Effect of slag composition on iron nuggets formation from carbon composite pellets

    Directory of Open Access Journals (Sweden)

    Alberto Eloy Anduze Nogueira

    2010-06-01

    Full Text Available Iron-carbon nuggets can be obtained by high temperature reduction of iron ore by carbonaceous material when both are agglomerated together as a carbon composite pellet. During this process, the stable oxides contained in the materials will form a slag. This work investigates the effect of this slag composition on iron nugget formation. Pellets were prepared with iron ore and two different carbonaceous materials. Through the addition of Portland® cement, silica and alumina the slag composition was varied to adjust the expected liquidus temperature to 1573 and 2273 K. It has been shown that the formation of iron nuggets is favored for slags presenting low liquidus temperature. In order to further investigate this phenomenon, pellets containing iron powder and carbonaceous material, together with previously prepared slags, were also submitted to high temperature, and it has been shown that iron carburization depends on slag composition.

  1. Slag Behavior in Gasifiers. Part II: Constitutive Modeling of Slag

    Energy Technology Data Exchange (ETDEWEB)

    Massoudi, Mehrdad [National Energy Technology Laboratory; Wang, Ping

    2013-02-07

    The viscosity of slag and the thermal conductivity of ash deposits are among two of the most important constitutive parameters that need to be studied. The accurate formulation or representations of the (transport) properties of coal present a special challenge of modeling efforts in computational fluid dynamics applications. Studies have indicated that slag viscosity must be within a certain range of temperatures for tapping and the membrane wall to be accessible, for example, between 1,300 °C and 1,500 °C, the viscosity is approximately 25 Pa·s. As the operating temperature decreases, the slag cools and solid crystals begin to form. Since slag behaves as a non-linear fluid, we discuss the constitutive modeling of slag and the important parameters that must be studied. We propose a new constitutive model, where the stress tensor not only has a yield stress part, but it also has a viscous part with a shear rate dependency of the viscosity, along with temperature and concentration dependency, while allowing for the possibility of the normal stress effects. In Part I, we reviewed, identify and discuss the key coal ash properties and the operating conditions impacting slag behavior.

  2. Slag Behavior in Gasifiers. Part II: Constitutive Modeling of Slag

    Directory of Open Access Journals (Sweden)

    Mehrdad Massoudi

    2013-02-01

    Full Text Available The viscosity of slag and the thermal conductivity of ash deposits are among two of the most important constitutive parameters that need to be studied. The accurate formulation or representations of the (transport properties of coal present a special challenge of modeling efforts in computational fluid dynamics applications. Studies have indicated that slag viscosity must be within a certain range of temperatures for tapping and the membrane wall to be accessible, for example, between 1,300 °C and 1,500 °C, the viscosity is approximately 25 Pa·s. As the operating temperature decreases, the slag cools and solid crystals begin to form. Since slag behaves as a non-linear fluid, we discuss the constitutive modeling of slag and the important parameters that must be studied. We propose a new constitutive model, where the stress tensor not only has a yield stress part, but it also has a viscous part with a shear rate dependency of the viscosity, along with temperature and concentration dependency, while allowing for the possibility of the normal stress effects. In Part I, we reviewed, identify and discuss the key coal ash properties and the operating conditions impacting slag behavior.

  3. Comparison of possibilities the blast furnace and cupola slag utilization by concrete production

    Directory of Open Access Journals (Sweden)

    D. Baricová

    2010-04-01

    Full Text Available In process of pig iron and cast iron production secondary raw materials and industrial wastes are formed The most abundant secondaryproduct originating in these processes are furnace slag. Blast furnace slag and cupola furnace slag originates from melting of gangue parts of metal bearing materials, slag forming additions and coke ash. In general, slag are compounds of oxides of metallic and non-metallic elements, which form chemical compounds and solutions with each other and also contain small volume of metals, sulfides of metals and gases. Chemical, mineralogical and physical properties of slag determinate their utilisation in different fields of industry.The paper presents results from the research of the blast furnace and cupola furnace slag utilization in the concrete production. Pilotexperiments of the concrete production were performed, by that the blast furnace and cupola furnace slag with a fractions of 0–4mm;4–8mm; 8–16mm were used as a natural substitute. A cupola furnace slag and combination of the blast furnace and cupola furnace slagwere used in the experiments. The analysis results show that such concretes are suitable for less demanding applications.

  4. A Thermodynamic Model for Predicting Phosphorus Partition between CaO-based Slags and Hot Metal during Hot Metal Dephosphorization Pretreatment Process Based on the Ion and Molecule Coexistence Theory

    Science.gov (United States)

    Yang, Xue-min; Li, Jin-yan; Chai, Guo-ming; Duan, Dong-ping; Zhang, Jian

    2016-08-01

    A thermodynamic model for predicting phosphorus partition L P between a CaO-based slags and hot metal during hot metal dephosphorization pretreatment process has been developed based on the ion and molecule coexistence theory (IMCT), i.e., the IMCT- L P model. The reaction abilities of structural units or ion couples in the CaO-based slags have been represented by the calculated mass action concentrations N i through the developed IMCT- N i model based on the IMCT. The developed IMCT- L P model has been verified to be valid through comparing with the measured L P as well as the predicted L P by two reported L P models from the literature. Besides the total phosphorus partition L P between the CaO-based slag and hot metal, the respective phosphorus partitions L P, i of nine dephosphorization products as P2O5, 3FeO·P2O5, 4FeO·P2O5, 2CaO·P2O5, 3CaO·P2O5, 4CaO·P2O5, 2MgO·P2O5, 3MgO·P2O5, and 3MnO·P2O5 can also be accurately predicted by the developed IMCT- L P model. The formed 3CaO·P2O5 accounts for 99.20 pct of dephosphorization products comparing with the generated 4CaO·P2O5 for 0.08 pct. The comprehensive effect of CaO+Fe t O, which can be described by the mass percentage ratio (pct Fe t O)/(pct CaO) or the mass action concentration ratio N_{Fe}t O/N_{Fe}t O N_{CaO}. N_{CaO}} as well as the mass percentage product (pct Fe t O) × (pct CaO) or the mass action concentration product N_{{{{Fe}}t {{O}}}}5 × N_{{CaO}}3 , controls dephosphorization ability of the CaO-based slags. A linear relationship of L P against (pct Fe t O)/(pct CaO) can be correlated compared with a parabolic relationship of L P against N_{Fe}t O/N_{Fe}t O N_{CaO}. N_{CaO}, while the linear relationship of L P against (pct Fe t O) × (pct CaO) or N_{Fe}t O5 × N_{CaO}3 can be established. Thus, the mass percentage product (pct Fe t O) × (pct CaO) and the mass action concentration product N_{Fe}t O5 × N_{CaO}3 are recommended to represent the comprehensive effect of CaO+Fe t O on

  5. ACCELERATED CARBONATION OF STEEL SLAG COMPACTS: DEVELOPMENT OF HIGH STRENGTH CONSTRUCTION MATERIALS

    Directory of Open Access Journals (Sweden)

    Mieke eQuaghebeur

    2015-12-01

    Full Text Available Mineral carbonation involves the capture and storage of carbon dioxide in carbonate minerals. Mineral carbonation presents opportunities for the recycling of steel slags and other alkaline residues that are currently landfilled. The Carbstone process was initially developed to transform non-hydraulic steel slags (stainless steel slag and basic oxygen furnace slags in high quality construction materials. The process makes use of accelerated mineral carbonation by treating different types of steel slags with CO2 at elevated pressure (up to 2 MPa and temperatures (20 to 140°C. For stainless steel slags raising the temperature from 20 to 140°C had a positive effect on the CO2 uptake, strength development and the environmental properties (i.e. leaching of Cr and Mo of the carbonated slag compacts. For BOF slags raising the temperature was not beneficial for the carbonation process. Elevated CO2 pressure and CO2 concentration of the feed gas had a positive effect on the CO2 uptake and strength development for both types of steel slags. In addition also the compaction force had a positive effect on the strength development. The carbonates that are produced in-situ during the carbonation reaction act as a binder, cementing the slag particles together. The carbonated compacts (Carbstones have technical properties that are equivalent to conventional concrete products. An additional advantage is that the carbonated materials sequester 100 to 150 g CO2/kg slag. The technology was developed on lab scale by optimisation of process parameters with regard to compressive strength development, CO2 uptake and environmental properties of the carbonated construction materials. The Carbstone technology was validated using (semi-industrial equipment and process conditions.

  6. UTILIZATION OF LIGHTWEIGHT MATERIALS MADE FROM COAL GASIFICATION SLAGS

    International Nuclear Information System (INIS)

    The integrated-gasification combined-cycle (IGCC) process is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, the process generates large amounts of solid waste, consisting of vitrified ash (slag) and some unconverted carbon. In previous projects, Praxis investigated the utilization of ''as-generated'' slags for a wide variety of applications in road construction, cement and concrete production, agricultural applications, and as a landfill material. From these studies, we found that it would be extremely difficult for ''as-generated'' slag to find large-scale acceptance in the marketplace even at no cost because the materials it could replace were abundantly available at very low cost. It was further determined that the unconverted carbon, or char, in the slag is detrimental to its utilization as sand or fine aggregate. It became apparent that a more promising approach would be to develop a variety of value-added products from slag that meet specific industry requirements. This approach was made feasible by the discovery that slag undergoes expansion and forms a lightweight material when subjected to controlled heating in a kiln at temperatures between 1400 and 1700 F. These results confirmed the potential for using expanded slag as a substitute for conventional lightweight aggregates (LWA). The technology to produce lightweight and ultra-lightweight aggregates (ULWA) from slag was subsequently developed by Praxis with funding from the Electric Power Research Institute (EPRI), Illinois Clean Coal Institute (ICCI), and internal resources. The major objectives of the subject project are to demonstrate the technical and economic viability of commercial production of LWA and ULWA from slag and to test the suitability of these aggregates for various applications. The project goals are to be accomplished in two phases: Phase I, comprising the production of LWA and ULWA from slag at the large pilot scale, and

  7. Gasification slag rheology and crystalline phase formation in titanium-calcium-alumina-silica-rich glass

    Energy Technology Data Exchange (ETDEWEB)

    Brooker, D.D. [Texaco, Inc., Beacon, NY (United States); Oh, M.S. [Hongik Univ., Seoul (Korea, Republic of)

    1996-10-01

    The Texaco Gasification Process employs a high temperature and pressure slagging gasifier, in which the viscosity of the slag plays a key role in determining operating conditions. The empirical models available in the literature as well as laboratory testing have concentrated on low titanium feeds. During the gasification of waste material, titanium oxide will become an important element in controlling the ash and slag behavior. Slag viscosity was measured at temperatures in the range of 1150-1500{degrees}C under reducing atmosphere with 0-30% titanium in combination with calcium-alumina-silica rich feeds to gain a better understanding of the slag theology. The slag viscosities with most titanium-rich slags showed the behavior of a crystalline slag with T{sub cv} of 1250{degrees}C. Crystalline phase analyses of the slag samples revealed that titanium oxide crystal will nucleate, but the glass phase is dominated by calcium-titanium-silicate and calcium-alumina-silicate glasses which have low melting points.

  8. A Microstructure Based Strength Model for Slag Blended Concrete with Various Curing Temperatures

    Directory of Open Access Journals (Sweden)

    Li-Na Zhang

    2016-01-01

    Full Text Available Ground granulated blast furnace slag, which is a byproduct obtained during steel manufacture, has been widely used for concrete structures in order to reduce carbon dioxide emissions and improve durability. This paper presents a numerical model to evaluate compressive strength development of slag blended concrete at isothermal curing temperatures and time varying curing temperatures. First, the numerical model starts with a cement-slag blended hydration model which simulates both cement hydration and slag reaction. The accelerations of cement hydration and slag reaction at elevated temperatures are modeled by Arrhenius law. Second, the gel-space ratios of hardening concrete are calculated using reaction degrees of cement and slag. Using a modified Powers’ gel-space ratio strength theory, the strength of slag blended concrete is evaluated considering both strengthening factors and weakening factors involved in strength development process. The proposed model is verified using experimental results of strength development of slag blended concrete with different slag contents and different curing temperatures.

  9. Developments in gold and silver recovery through flotation in processing of gold ore slags; Avances en la recuperacion de oro y plata mediante flotacion en escorias de procesamiento de menas de oro

    Energy Technology Data Exchange (ETDEWEB)

    Hidalgo, N.; Diaz, A.; Bazan, V.; Sarquis, P.

    2015-07-01

    The aim of this work is to recover and improve the extraction of gold and silver present in smelting slags through various mineralogical processes applicable in gold ores. The slag was concentrated in a Knelson type centrifuge, two concentrates (C1 and C2 and a tailing T1) being obtained. In order to improve the recovery, three series of rougher flotation tests were conducted on the tailing T1. The variables analyzed were: particle size, type of collectors (xanthates, di-monothiophosphate) and flotation time. It was deduced that by applying gravity concentration, the recovery of Au and Ag (Knelson centrifuge) is 42.0% and 13.7%, respectively. Au recovery is improved by 87.7% through the flotation of the centrifuge separation tailings, whereas that for Ag is 47.4%. The optimum conditions were: particle size 200 mesh, collectors: PAX (15.8 g/t), F-C5439 (18.75 g/t), MIBC frother (12.5g/t) and 8.5 minutes of flotation time. (Author)

  10. Slagging and Fouling Characteristics of HRSG for Ferrosilicon Electric Furnaces

    Directory of Open Access Journals (Sweden)

    Yungang Wang

    2015-02-01

    Full Text Available The slagging and fouling characteristics of the heat recovery steam generator (HRSG for ferrosilicon electric furnaces are discussed in this paper. Three ash samples were taken from the HRSG of a ferrosilicon furnace in Ningxia Province, China, which suffered from serious slagging and fouling. X-ray fluorescence (XRF, X-ray powder diffraction (XRD and scanning electron microscope (SEM were used to analyze the ash samples. The results show that low melting point salt Na2SO4 and composite salts Na (AlSi3O8 and 3K2SO4·CaSO4 deposit on the superheater tube walls in aerosol form and solidify to form the initial slag layer. With the continuous deposition of the low melting point compounds, more and more ash particles in the flue gas adhere to the slag surface to form a thicker slag. Low melting point composite salt NaO·Al2O3·SiO2 is absorbed on the evaporator tube walls in aerosol form. With the deposition of NaO·Al2O3·SiO2, more and more ash particles are absorbed to form the fouling. Since there is less space between pin-finned tubes, the large iron-rich slag particles are easily deposited on tube walls and fin surfaces, which is advantageous to the fouling process. There are large quantities of superfine ash particles in the flue gas that easily adhere to other particles or tube walls, which facilitates the slagging and fouling process.

  11. Molybdate adsorption from steel slag eluates by subsoils.

    Science.gov (United States)

    Matern, K; Rennert, T; Mansfeldt, T

    2013-11-01

    Steel slags are industrial by-products which are generated in large amounts worldwide, e.g. 150-230×10(6) Mg in 2012, and which are partly used for construction. Molybdenum (Mo) can be added during steel processing in order to harden the steel. The objective of this study was to evaluate the adsorption behaviour of molybdate (MoO4(2-)) from slag eluates in subsoils. Molybdate batch adsorption experiments were carried out with eluates obtained from two different kinds of steel slags (i) LD slag (Linz-Donawitz operation, LDS) and (ii) electric arc furnace slag (EAF) to assess the risk that may arise from the contamination of groundwater by the leaching of molybdate. Six different subsoils were chosen in order to provide a wide range of chemical properties (pH 4.0-7.6; dithionite-extractable Fe 0.73-14.7 g kg(-1)). Molybdate adsorption experiments were carried out at the pH of the steel slag eluates (pH 11-12) as well as at pH values adjusted to the soil pH. The data were evaluated with the Freundlich equation. Molybdate adsorption exhibited a maximum near pH 4 for steel slag eluates adjusted to the soil pH, and decreased rapidly with increasing pH until adsorption was virtually zero at pH>11. Adsorption was greater for soils with high amounts of dithionite-extractable Fe oxides. The extent and behaviour of molybdate adsorption from both eluates was similar. After a reaction time of 24h, the pH of the EAF slag eluate was lower than that of the LD steel slag eluate, which was caused by different acid buffer capacities. Some soils were able to decrease the pH of the EAF slag eluates by about 4 pH units, enhancing the adsorption of molybdate. Transport simulations indicated that molybdate discharge is low in acidic soils. PMID:23973286

  12. Crystallization Behavior of Copper Smelter Slag During Molten Oxidation

    Science.gov (United States)

    Fan, Yong; Shibata, Etsuro; Iizuka, Atsushi; Nakamura, Takashi

    2015-10-01

    Copper slag is composed of iron silicate obtained by smelting copper concentrate and silica flux. One of the most important criteria for the utilization of this secondary resource is the recovery of iron from the slag matrix to decrease the volume of dumped slag. The molten oxidation process with crushing magnetic separation appears to be a more sustainable approach and is based on directly blowing oxidizing gas onto molten slag after the copper smelting process. In the current study, using an infrared furnace, the crystallization behavior of the slag during molten oxidation was studied to better understand the trade-off between magnetite and hematite precipitations, as assessed by X-ray diffraction (using an internal standard). Furthermore, the crystal morphology was examined using a laser microscope and Raman imaging system to understand the iron oxide transformation, and the distribution of impurities such as Cu, Zn, As, Cr, and Pb were complemented with scanning electron microscopy and energy dispersive spectroscopy. In addition, the reaction mechanism was investigated with a focus on the oxidation processes.

  13. Canyon dissolution of sand, slag, and crucible residues

    International Nuclear Information System (INIS)

    An alternative to the FB-Line scrap recovery dissolver was desired for the dissolution of sand, slag, and crucible (SS and C) residues from the plutonium reduction process due to the potential generation of hydrogen gas concentrations above the lower flammability limit. To address this concern, a flowsheet was developed for the F-Canyon dissolvers. The dissolvers are continually purged with nominally 33 SCFM of air; therefore the generation of flammable gas concentrations should not be a concern. Following removal of crucible fragments, small batches of the remaining sand fines or slag chunks containing less than approximately 350 grams of plutonium can be dissolved using the center insert in each of the four annular dissolver ports to address nuclear criticality safety concerns. Complete dissolution of the sand fines and slag chunks was achieved in laboratory experiments by heating between 75 and 85 degrees Celsius in a 9.3M nitric acid/0.013M (hydrogen) fluoride solution. Under these conditions, the sand and slag samples dissolved between 1 and 3 hours. Complete dissolution of plutonium and calcium fluorides in the slag required adjusting the dissolver solution to 7.5 wt% aluminum nitrate nonahydrate (ANN). Once ANN was added to a dissolver solution, further dissolution of any plutonium oxide (PuO2) in successive charges was not practical due to complexation of the fluoride by aluminum. During the laboratory experiments, well mixed solutions were necessary to achieve rapid dissolution rates. When agitation was not provided, sand fines dissolved very slowly. Measurement of the hydrogen gas generation rate during dissolution of slag samples was used to estimate the amount of metal in the chunks. Depending upon the yield of the reduction, the values ranged between approximately 1 (good yield) and 20% (poor yield). Aging of the slag will reduce the potential for hydrogen generation as calcium metal oxidizes over time. The potential for excessive corrosion in the

  14. Artificial intelligence-based computer modeling tools for controlling slag foaming in electric arc furnaces

    Science.gov (United States)

    Wilson, Eric Lee

    Due to increased competition in a world economy, steel companies are currently interested in developing techniques that will allow for the improvement of the steelmaking process, either by increasing output efficiency or by improving the quality of their product, or both. Slag foaming is one practice that has been shown to contribute to both these goals. However, slag foaming is highly dynamic and difficult to model or control. This dissertation describes an effort to use artificial intelligence-based tools (genetic algorithms, fuzzy logic, and neural networks) to both model and control the slag foaming process. Specifically, a neural network is trained and tested on slag foaming data provided by a steel plant. This neural network model is then controlled by a fuzzy logic controller, which in turn is optimized by a genetic algorithm. This tuned controller is then installed at a steel plant and given control be a more efficient slag foaming controller than what was previously used by the steel plant.

  15. Phase chemical composition of slag from a direct nickel flash furnace and associated slag cleaning furnace

    International Nuclear Information System (INIS)

    During the recovery of base metals from the Bushveld Igneous Complex ores, South Africa, a two-stage process is used to ensure complete recovery of nickel from the ore. A nickel flash smelting furnace is initially used to obtain the valuable metal but the loss of nickel in the slag amounts to about 4 % and thus an electric slag-cleaning furnace has to be subsequently used to reduce the loss of the valuable metal to less than 0.5 % nickel oxide in the slag. The Fe2 + /Fe3 +  ratio and mineralogy in the two different furnaces differ and can be used as a tool to determine the efficiency of the nickel recovered in the two-stage process. By means of XRD, SEM/EDS and Mössbauer spectroscopy the Fe2 + /Fe3 +  ratio and the amount of magnetite was determined in each furnace, which was then used as an indicator of the effectiveness of the whole process.

  16. Phase chemical composition of slag from a direct nickel flash furnace and associated slag cleaning furnace

    Energy Technology Data Exchange (ETDEWEB)

    Waanders, F. B., E-mail: frans.waanders@nwu.ac.za [North-West University, School of Chemical and Minerals Engineering (South Africa); Nell, J., E-mail: Johannes.Nell@hatch.co.za [Hatch (South Africa)

    2013-04-15

    During the recovery of base metals from the Bushveld Igneous Complex ores, South Africa, a two-stage process is used to ensure complete recovery of nickel from the ore. A nickel flash smelting furnace is initially used to obtain the valuable metal but the loss of nickel in the slag amounts to about 4 % and thus an electric slag-cleaning furnace has to be subsequently used to reduce the loss of the valuable metal to less than 0.5 % nickel oxide in the slag. The Fe{sup 2 + }/Fe{sup 3 + } ratio and mineralogy in the two different furnaces differ and can be used as a tool to determine the efficiency of the nickel recovered in the two-stage process. By means of XRD, SEM/EDS and Moessbauer spectroscopy the Fe{sup 2 + }/Fe{sup 3 + } ratio and the amount of magnetite was determined in each furnace, which was then used as an indicator of the effectiveness of the whole process.

  17. Phase chemical composition of slag from a direct nickel flash furnace and associated slag cleaning furnace

    Science.gov (United States)

    Waanders, F. B.; Nell, J.

    2013-04-01

    During the recovery of base metals from the Bushveld Igneous Complex ores, South Africa, a two-stage process is used to ensure complete recovery of nickel from the ore. A nickel flash smelting furnace is initially used to obtain the valuable metal but the loss of nickel in the slag amounts to about 4 % and thus an electric slag-cleaning furnace has to be subsequently used to reduce the loss of the valuable metal to less than 0.5 % nickel oxide in the slag. The Fe2 + /Fe3 + ratio and mineralogy in the two different furnaces differ and can be used as a tool to determine the efficiency of the nickel recovered in the two-stage process. By means of XRD, SEM/EDS and Mössbauer spectroscopy the Fe2 + /Fe3 + ratio and the amount of magnetite was determined in each furnace, which was then used as an indicator of the effectiveness of the whole process.

  18. PERFORMANCE OF PULVERIZED SLAG-SUBSTITUTED CEMENT

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The Portland cement is equivalently substituted by slag micropowders with various specific areas. The workability,activity and acid-corrosion resistance of the slag-substituted cements are investigated,the activation of gypsum is discussed,also the porosity and pore distribution of mortars of the slag micropowders cement are determined by mercury intrusion porosimetry.

  19. Changes in mineralogical and leaching properties of converter steel slag resulting from accelerated carbonation at low CO2 pressure

    International Nuclear Information System (INIS)

    Highlights: → Accelerated carbonation studied to improve environmental properties of steel slag. → Carbonation found to occur predominantly at surface of the steel slag grains. → Combined geochemical modelling and mineral analysis revealed controlling processes. → Enhanced V-leaching with di-Ca silicate (C2S) dissolution identified as major source. → Identified mineral transformations provide guidance for further quality improvement. - Abstract: Steel slag can be applied as substitute for natural aggregates in construction applications. The material imposes a high pH (typically 12.5) and low redox potential (Eh), which may lead to environmental problems in specific application scenarios. The aim of this study is to investigate the potential of accelerated steel slag carbonation, at relatively low pCO2 pressure (0.2 bar), to improve the environmental pH and the leaching properties of steel slag, with specific focus on the leaching of vanadium. Carbonation experiments are performed in laboratory columns with steel slag under water-saturated and -unsaturated conditions and temperatures between 5 and 90 oC. Two types of steel slag are tested; free lime containing (K3) slag and K1 slag with a very low free lime content. The fresh and carbonated slag samples are investigated using a combination of leaching experiments, geochemical modelling of leaching mechanisms and microscopic/mineralogical analysis, in order to identify the major processes that control the slag pH and resulting V leaching. The major changes in the amount of sequestered CO2 and the resulting pH reduction occurred within 24 h, the free lime containing slag (K3-slag) being more prone to carbonation than the slag with lower free lime content (K1-slag). While carbonation at these conditions was found to occur predominantly at the surface of the slag grains, the formation of cracks was observed in carbonated K3 slag, suggesting that free lime in the interior of slag grains had also reacted. The p

  20. Criteria determining the selection of slags for the melt decontamination of radioactively contaminated stainless steel by electroslag remelting

    International Nuclear Information System (INIS)

    Electroslag remelting is an excellent process choice for the melt decontamination of radioactively contaminated metals. ESR furnaces are easily enclosed and do not make use of refractories which could complicate thermochemical interactions between molten metal and slag. A variety of cleaning mechanisms are active during melting; radionuclides may be partitioned to the slag by means of thermochemical reaction, electrochemical reaction, or mechanical entrapment. At the completion of melting, the slag is removed from the furnace in solid form. The electroslag process as a whole is greatly affected by the chemical and physical properties of the slag used. When used as a melt decontamination scheme, the ESR process may be optimized by selection of the slag. In this research, stainless steel bars were coated with non-radioactive surrogate elements in order to simulate surface contamination. These bars were electroslag remelted using slags of various chemistries. The slags investigated were ternary mixtures of calcium fluoride, calcium oxide, and alumina. The final chemistries of the stainless steel ingots were compared with those predicted by the use of a Free Energy Minimization Modeling technique. Modeling also provided insight into the chemical mechanisms by which certain elements are captured by a slag. Slag selection was also shown to have an impact on the electrical efficiency of the process as well as the surface quality of the ingots produced

  1. Study on cementitious properties of steel slag

    Directory of Open Access Journals (Sweden)

    Zhu G.

    2013-01-01

    Full Text Available The converter steel slag chemical and mineral components in China’s main steel plants have been analysed in the present paper. The electronic microscope, energy spectrum analysis, X-ray diffraction analysis confirmed the main mineral compositions in the converter slag. Converter slag of different components were grounded to obtain a powder with specific surface area over 400m2/kg, making them to take place some part of the cement in the concrete as the admixture and carry out the standard tests. The results indicate that the converter slag can be used as cementitious materials for construction. Furthermore, physical mechanic and durability tests on the concrete that certain amount of cement be substituted by converter steel slag powder from different steel plants are carried out, the results show that the concrete with partial substitution of steel slag powder has the advantages of higher later period strength, better frost resistance, good wear resistance and lower hydration heat, etc. This study can be used as the technical basis for “Steel Slag Powder Used For Cement And Concrete”, “Steel Slag Portland Cement”, “Low Heat Portland Steel Slag Cement”, “Steel Slag Road Cement” in China, as well as a driving force to the works of steel slag utilization with high-value addition, circular economy, energy conservation and discharge reduction in the iron and steel industry.

  2. Assessment of toxicity and hazard class slag of incinerator

    Directory of Open Access Journals (Sweden)

    Demura V.I.

    2016-02-01

    Full Text Available Researches of the contents soluble forms of heavy metals in waste are executed. The estimation of a degree of toxicity of products of thermal processing of waste is lead. It is established, that slag of an incinerate factory concerns to І class of danger under the contents of mobile forms of heavy meta

  3. Phosphate removal from domestic wastewater using thermally modified steel slag.

    Science.gov (United States)

    Yu, Jian; Liang, Wenyan; Wang, Li; Li, Feizhen; Zou, Yuanlong; Wang, Haidong

    2015-05-01

    This study was performed to investigate the removal of phosphate from domestic wastewater using a modified steel slag as the adsorbent. The adsorption effects of alkalinity, salt, water, and thermal modification were investigated. The results showed that thermal activation at 800°C for 1 hr was the optimum operation to improve the adsorption capacity. The adsorption process of the thermally modified slag was well described by the Elovich kinetic model and the Langmuir isotherm model. The maximum adsorption capacity calculated from the Langmuir model reached 13.62 mg/g. Scanning electron microscopy indicated that the surface of the modified slag was cracked and that the texture became loose after heating. The surface area and pore volume did not change after thermal modification. In the treatment of domestic wastewater, the modified slag bed (35.5 kg) removed phosphate effectively and operated for 158 days until the effluent P rose above the limit concentration of 0.5 mg/L. The phosphate fractionation method, which is often applied in soil research, was used to analyze the phosphate adsorption behavior in the slag bed. The analysis revealed that the total contents of various Ca-P forms accounted for 81.4%-91.1%, i.e., Ca10-P 50.6%-65.1%, Ca8-P 17.8%-25.0%, and Ca2-P 4.66%-9.20%. The forms of Al-P, Fe-P, and O-P accounted for only 8.9%-18.6%. The formation of Ca10-P precipitates was considered to be the main mechanism of phosphate removal in the thermally modified slag bed. PMID:25968262

  4. Visualisation and quantification of heavy metal accessibility in smelter slags: The influence of morphology on availability.

    Science.gov (United States)

    Morrison, Anthony L; Swierczek, Zofia; Gulson, Brian L

    2016-03-01

    The Imperial Smelting Furnace (ISF) for producing lead and zinc simultaneously has operated on four continents and in eleven countries from the 1950's. One of the process changes that the ISF introduced was the production of a finely granulated slag waste. Although this slag contained significant amounts of residual lead (Pb) and zinc (Zn), because of its glassy nature it was considered environmentally benign. From the Cockle Creek smelter near Boolaroo at the northern end of Lake Macquarie, NSW, Australia, it is estimated that around 2.1 million tonnes of the fine slag was distributed into the community and most remains where it was originally utilised. Residual tonnages of slag of this magnitude are common worldwide wherever the ISF operated. Studies of base metal smelting slags have concluded that mineralogical and morphological characteristics of the slag play a critical role in moderating environmental release of toxic elements. Scanning electron microscopy (SEM) and microanalysis of the ISF slags has shown that the Pb and associated elements are present as discrete nodules (∼6-22 μm) in the slag and that they are not associated with Zn which is contained in the glass slag phase. Using an automated SEM and analysis technique (QEMSCAN(®)) to "map" the mineralogical structure of the particles, it was possible to quantitatively determine the degree of access infiltrating fluids might have to the reaction surface of the Pb phases. The level of access decreases with increasing particle size, but in even the largest sized particles (-3350 + 2000 μm) nearly 80% of the Pb-containing phases were totally or partially accessible. These results provide evidence that the toxic elements in the slags are not contained by the glassy phase and will be vulnerable to leaching over time depending on their individual phase reactivity. PMID:26784748

  5. Slag Behavior in Gasifiers. Part I: Influence of Coal Properties and Gasification Conditions

    Directory of Open Access Journals (Sweden)

    Ping Wang

    2013-02-01

    Full Text Available In the entrained-flow gasifiers used in integrated gasification combined cycle (IGCC plants, the majority of mineral matter transforms to liquid slag on the wall of the gasifier and flows out the bottom. However, a small fraction of the mineral matter is entrained (as fly ash with the raw syngas out of the gasifier to downstream processing. This molten/sticky fly ash could cause fouling of the syngas cooler. To improve gasification availability through better design and operation of the gasification process, a better understanding of slag behavior and the characteristics of the slagging process is needed. Char/ash properties, gas compositions in the gasifier, the gasifier wall structure, fluid dynamics, and plant operating conditions (mainly temperature and oxygen/carbon ratio all affect slagging behavior. Because coal has varying ash content and composition, different operating conditions are required to maintain the slag flow and limit problems downstream. In Part I, we review the main types and the operating conditions of entrained-flow gasifiers and coal properties used in IGCC plants; we identify and discuss the key coal ash properties and the operating conditions impacting slag behavior; finally, we summarize the coal quality criteria and the operating conditions in entrained-flow gasifiers. In Part II, we discuss the constitutive modeling related to the rheological studies of slag flow.

  6. Hydration characteristics and environmental friendly performance of a cementitious material composed of calcium silicate slag.

    Science.gov (United States)

    Zhang, Na; Li, Hongxu; Zhao, Yazhao; Liu, Xiaoming

    2016-04-01

    Calcium silicate slag is an alkali leaching waste generated during the process of extracting Al2O3 from high-alumina fly ash. In this research, a cementitious material composed of calcium silicate slag was developed, and its mechanical and physical properties, hydration characteristics and environmental friendly performance were investigated. The results show that an optimal design for the cementitious material composed of calcium silicate slag was determined by the specimen CFSC7 containing 30% calcium silicate slag, 5% high-alumina fly ash, 24% blast furnace slag, 35% clinker and 6% FGD gypsum. This blended system yields excellent physical and mechanical properties, confirming the usefulness of CFSC7. The hydration products of CFSC7 are mostly amorphous C-A-S-H gel, rod-like ettringite and hexagonal-sheet Ca(OH)2 with small amount of zeolite-like minerals such as CaAl2Si2O8·4H2O and Na2Al2Si2O8·H2O. As the predominant hydration products, rod-like ettringite and amorphous C-A-S-H gel play a positive role in promoting densification of the paste structure, resulting in strength development of CFSC7 in the early hydration process. The leaching toxicity and radioactivity tests results indicate that the developed cementitious material composed of calcium silicate slag is environmentally acceptable. This study points out a promising direction for the proper utilization of calcium silicate slag in large quantities. PMID:26691955

  7. Toxicity assessment and geochemical model of chromium leaching from AOD slag.

    Science.gov (United States)

    Liu, Bao; Li, Junguo; Zeng, Yanan; Wang, Ziming

    2016-02-01

    AOD (Argon Oxygen Decarburization) slag is a by-product of the stainless steel refining process. The leaching toxicity of chromium from AOD slag cannot be ignored in the recycling process of the AOD slag. To assess the leaching toxicity of the AOD slag, batch leaching tests have been performed. PHREEQC simulations combined with FactSage were carried out based on the detailed mineralogical analysis and petrophysical data. Moreover, Pourbaix diagram of the Cr-H2O system was protracted by HSC 5.0 software to explore the chromium speciation in leachates. It was found that AOD slag leachate is an alkaline and reductive solution. The Pourbaix diagram of the Cr-H2O system indicated that trivalent chromium, such as Cr(OH)4(-), is the major chromium species in the experimental Eh-pH region considered. However, toxic hexavalent chromium was released with maximum concentrations of 30 µg L(-1) and 18 µg L(-1) at L/S 10 and 100, respectively, during the earlier leaching stage. It concluded that the AOD slag possessed a certain leaching toxicity. After 10 d of leaching, trivalent chromium was the dominant species in the leachates, which corresponded to the results of PHREEQC simulation. Leaching toxicity of AOD slag is based on the chromium speciation and its transformation. Great attention should be focused on such factors as aging, crystal form of chromium-enriched minerals, and electrochemical characteristics of the leachates. PMID:26583286

  8. Reproducing ten years of road ageing - Accelerated carbonation and leaching of EAF steel slag

    International Nuclear Information System (INIS)

    Reuse of industrial aggregates is still hindered by concern for their long-term properties. This paper proposes a laboratory method for accelerated ageing of steel slag, to predict environmental and technical properties, starting from fresh slag. Ageing processes in a 10-year old asphalt road with steel slag of electric arc furnace (EAF) type in the subbase were identified by scanning electron microscopy (SEM) and leaching tests. Samples from the road centre and the pavement edge were compared with each other and with samples of fresh slag. It was found that slag from the pavement edge showed traces of carbonation and leaching processes, whereas the road centre material was nearly identical to fresh slag, in spite of an accessible particle structure. Batches of moisturized road centre material exposed to oxygen, nitrogen or carbon dioxide (CO2) were used for accelerated ageing. Time (7-14 days), temperature (20-40 oC) and initial slag moisture content (8-20%) were varied to achieve the carbonation (decrease in pH) and leaching that was observed in the pavement edge material. After ageing, water was added to assess leaching of metals and macroelements. 12% moisture, CO2 and seven days at 40 oC gave the lowest pH value. This also reproduced the observed ageing effect for Ca, Cu, Ba, Fe, Mn, Pb, Ca (decreased leaching) and for V, Si, and Al (increased leaching). However, ageing effects on SO4, DOC and Cr were not reproduced.

  9. Experimental study on sulfur removal from ladle furnace refining slag in hot state by blowing Air

    Institute of Scientific and Technical Information of China (English)

    Li-hua Zhao; Lu Lin; Qi-fan Wu

    2016-01-01

    In view of the present problem of sulfur enrichment in the metallurgical recycling process of ladle furnace (LF) refining slag, a simple and efficient method of removing sulfur from this slag was proposed. The proposed method is compatible with current steelmaking processes. Sulfur removal from LF refining slag for SPHC steel (manufactured at a certain steel plant in China) by blowing air in the hot state was studied by using hot-state experiments in a laboratory. The FactSage software, a carbon/sulfur analyzer, and scanning electron micros-copy in conjunction with energy-dispersive X-ray spectroscopy were used to test and analyze the sulfur removal effect and to investigate factors influencing sulfur removal rate. The results show that sulfur ions in LF refining slag can be oxidized into SO2 by O2 at high tempera-ture by blowing air into molten slag; SO2 production was observed to reach a maximum with a small amount of blown O2 when the tem-perature exceeded 1350°C. At 1370°C and 1400°C, experimental LF refining slag is in the liquid state and exhibits good fluidity; under these conditions, the sulfur removal effect by blowing air is greater than 90wt% after 60 min. High temperature and large air flow rate are benefi-cial for removing sulfur from LF refining slag; compared with air flow rate, temperature has a greater strongly influences on the sulfur re-moval.

  10. 转炉钢渣热能回收利用的理论分析和实践%The Theory Analysis and Practice of Heat Recovery Utilization in Converter Steel-slag Treatment Process

    Institute of Scientific and Technical Information of China (English)

    赵旭章; 俞海明

    2015-01-01

    钢渣的热能回收利用,是目前国内外冶金企业关注的焦点。八钢公司自主开发了利用钢渣热能改质、利用钢渣烘烤潮湿原辅料等工艺方法,实践结果表明,通过梯级利用钢渣热能的工艺方法获得了好的效果。%The heat energy recycling of steel-slag is the focus of metallurgy enterprise .Bayi Steel independently devel-ops several methods, using steel-slag thermal to improve quality and using steel-slag to roast damp raw materials. Ac-cording to the practical results, it obtains a good effect with steel-slag thermal cascaded utilization.

  11. Effect of Coal Properties and Operation Conditions on Flow Behavior of Coal Slag in Entrained Flow Gasifiers: A Brief Review

    Energy Technology Data Exchange (ETDEWEB)

    Wang,Ping; Massoudi, Mehrdad

    2011-01-01

    Integrated gasification combined cycle (IGCC) is a potentially promising clean technology with an inherent advantage of low emissions, since the process removes contaminants before combustion instead of from flue gas after combustion, as in a conventional coal steam plant. In addition, IGCC has potential for cost-effective carbon dioxide capture. Availability and high capital costs are the main challenges to making IGCC technology more competitive and fully commercial. Experiences from demonstrated IGCC plants show that, in the gasification system, low availability is largely due to slag buildup in the gasifier and fouling in the syngas cooler downstream of the gasification system. In the entrained flow gasifiers used in IGCC plants, the majority of mineral matter transforms to liquid slag on the wall of the gasifier and flows out the bottom. However, a small fraction of the mineral matter (as fly ash) is entrained with the raw syngas out of the gasifier to downstream processing. This molten/sticky fly ash could cause fouling of the syngas cooler. Therefore, it is preferable to minimize the quantity of fly ash and maximize slag. In addition, the hot raw syngas is cooled to convert any entrained molten fly slag to hardened solid fly ash prior to entering the syngas cooler. To improve gasification availability through better design and operation of the gasification process, better understanding of slag behavior and characteristics of the slagging process are needed. Slagging behavior is affected by char/ash properties, gas compositions in the gasifier, the gasifier wall structure, fluid dynamics, and plant operating conditions (mainly temperature and oxygen/carbon ratio). The viscosity of the slag is used to characterize the behavior of the slag flow and is the dominating factor to determine the probability that ash particles will stick. Slag viscosity strongly depends on the temperature and chemical composition of the slag. Because coal has varying ash content and

  12. Changes in mineralogical and leaching properties of converter steel slag resulting from accelerated carbonation at low CO2 pressure

    International Nuclear Information System (INIS)

    Steel slag can be applied as substitute for natural aggregates in construction applications. The material imposes a high pH (typically 12.5) and low redox potential (Eh), which may lead to environmental problems in specific application scenarios. The aim of this study is to investigate the potential of accelerated steel slag carbonation, at relatively low pCO2 pressure (0.2 bar), to improve the environmental pH and the leaching properties of steel slag, with specific focus on the leaching of vanadium. Carbonation experiments are performed in laboratory columns with steel slag under water-saturated and -unsaturated conditions and temperatures between 5 and 90C. Two types of steel slag are tested; free lime containing (K3) slag and K1 slag with a very low free lime content. The fresh and carbonated slag samples are investigated using a combination of leaching experiments, geochemical modelling of leaching mechanisms and microscopic/mineralogical analysis, in order to identify the major processes that control the slag pH and resulting V leaching. The major changes in the amount of sequestered CO2 and the resulting pH reduction occurred within 24 h, the free lime containing slag (K3-slag) being more prone to carbonation than the slag with lower free lime content (K1-slag). While carbonation at these conditions was found to occur predominantly at the surface of the slag grains, the formation of cracks was observed in carbonated K3 slag, suggesting that free lime in the interior of slag grains had also reacted. The pH of the K3 slag (originally pH ± 12.5) was reduced by about 1.5 units, while the K1 slag showed a smaller decrease in pH from about 11.7 to 11.1. However, the pH reduction after carbonation of the K3 slag was observed to lead to an increased V-leaching. Vanadium leaching from the K1 slag resulted in levels above the limit values of the Dutch Soil Quality Decree, for both the untreated and carbonated slag. V-leaching from the carbonated K3 slag remained

  13. LEACHING OF SLAG FROM STEEL RECYCLING: RADIONUCLIDES AND STABLE ELEMENTS. DATA REPORT, JAN.15, 1997, REVISED SEPT.9, 1997

    Energy Technology Data Exchange (ETDEWEB)

    FUHRMANN,M.SCHOONEN,M.

    2003-07-31

    Of primary importance to this study are releases of radionuclides from slags. However, releases of other constituents also provide valuable information on releases of elements that may be toxic (e.g. Cr) or that may be used as analogs for radionuclides (e.g. K for Cs). In addition, leaching of bulk constituents from the slag gives information on weathering rates of the bulk material that can be used to estimate releases of non-leachable elements. Consequently, we have examined leaching of: radionuclides from those sloags that contain them; bulk elemental constituents of the slags; anionic constituents; trace elements, through spot checks of concentrations in leachates. Analysis by ICP of elemental constituents in leachates from radioactive samples was limited to those leachate samples that contained no detectable radionuclides, to avoid contamination of the ICP. In this data report we present leaching results for five slags that were produced by recycling steel. Two of the slags were generated at facilities that treat radioactively contaminated scrap, consequently the slag contains radionuclides. The slag from the other three was not contaminated. Because of this, we were able to examine the chemical composition of the slag and of the leachate generated during tests of these slags. For these materials we believe that leach rates of the stable elements can be used as analogs for radionuclides if the same steel processing method were used for radioactive material.

  14. On the problem of zinc extraction from the slags of lead heat

    Science.gov (United States)

    Kozyrev, V. V.; Besser, A. D.; Paretskii, V. M.

    2013-12-01

    The possibilities of zinc extraction from the slags of lead heat are studied as applied to the ZAO Karat-TsM lead plant to be built for processing ore lead concentrates. The process of zinc extraction into commercial fumes using the technology of slag fuming by natural gas developed in Gintsvetmet is recommended for this purpose. Technological rules are developed for designing a commercial fuming plant, as applied to the conditions of the ZAO Karat-TsM plant.

  15. Life Cycle Assessment of Internal Recycling Options of Steel Slag in Chinese Iron and Steel Industry%Life Cycle Assessment of Internal Recycling Options of Steel Slag in Chinese Iron and Steel Industry

    Institute of Scientific and Technical Information of China (English)

    CHEN Bo; YANG Jian-xin; OUYANG Zhi-yun

    2011-01-01

    The internal recycling process of BOF slag which is one of the huge solid wastes from iron and steel indus try was emphasized. Based on the four scenarios of different internal recycling strategies for BOF slag, life cycle assessment (LCA) as a valuable t

  16. NONEQUILIBRIUM SULFUR CAPTURE & RETENTION IN AN AIR COOLED SLAGGING COAL COMBUSTOR

    Energy Technology Data Exchange (ETDEWEB)

    Bert Zauderer

    2003-04-21

    Calcium oxide injected in a slagging combustor reacts with the sulfur from coal combustion to form sulfur-bearing particles. The reacted particles impact and melt in the liquid slag layer on the combustor wall by the centrifugal force of the swirling combustion gases. Due to the low solubility of sulfur in slag, it must be rapidly drained from the combustor to limit sulfur gas re-evolution. Prior analyses and laboratory scale data indicated that for Coal Tech's 20 MMBtu/hour, air-cooled, slagging coal combustor slag mass flow rates in excess of 400 lb/hr should limit sulfur re-evolution. The objective of this 42-month project was to validate this sulfur-in-slag model in a group of combustor tests. A total of 36 days of testing on the combustor were completed during the period of performance of this project. This was more that double the 16 test days that were required in the original work statement. The extra tests were made possible by cost saving innovations that were made in the operation of the combustor test facility and in additional investment of Coal Tech resources in the test effort. The original project plan called for two groups of tests. The first group of tests involved the injection of calcium sulfate particles in the form of gypsum or plaster of Paris with the coal into the 20 MMBtu/hour-combustor. The second group of tests consisted of the entire two-step process, in which lime or limestone is co-injected with coal and reacts with the sulfur gas released during combustion to form calcium sulfate particles that impact and dissolve in the slag layer. Since this sulfur capture process has been validated in numerous prior tests in this combustor, the primary effort in the present project was on achieving the high slag flow rates needed to retain the sulfur in the slag.

  17. Effect of blast furnace slag on self-healing of microcracks in cementitious materials

    International Nuclear Information System (INIS)

    The physico-chemical process of self-healing in blast furnace slag cement paste was investigated in this paper. With a high slag content i.e., 66% in cement paste and saturated Ca(OH)2 solution as activator, it was found that the reaction products formed in cracks are composed of C-S-H, ettringite, hydrogarnet and OH–hydrotalcite. The fraction of C-S-H in the reaction products is much larger than the other minerals. Large amount of ettringite formed in cracks indicates the leaching of SO42− ions from the bulk paste and consequently the recrystallization. Self-healing proceeds fast within 50 h and then slows down. According to thermodynamic modeling, when the newly formed reaction products are carbonated, the filling fraction of crack increases first and then decreases. Low soluble minerals such as silica gel, gibbsite and calcite are formed. Compared to Portland cement paste, the potential of self-healing in slag cement paste is higher when the percentage of slag is high. - Highlights: • Self-healing reaction products in slag cement paste were characterized. • Self-healing reaction products formed in time were quantified with image analysis. • Self-healing in slag cement paste was simulated with a reactive transport model. • Effect of carbonation on self-healing was investigated by thermodynamic modeling. • Effect of slag on self-healing was discussed based on experiments and simulation

  18. Effect of blast furnace slag on self-healing of microcracks in cementitious materials

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Haoliang, E-mail: haoliang.huang@tudelft.nl [Microlab, Faculty of Civil Engineering and Geosciences, Delft University of Technology (Netherlands); Ye, Guang [Microlab, Faculty of Civil Engineering and Geosciences, Delft University of Technology (Netherlands); Magnel Laboratory for Concrete Research, Department of Structural Engineering, Ghent University (Belgium); Damidot, Denis [Université Lille Nord de France (France); EM Douai, LGCgE-MPE-GCE, Douai (France)

    2014-06-01

    The physico-chemical process of self-healing in blast furnace slag cement paste was investigated in this paper. With a high slag content i.e., 66% in cement paste and saturated Ca(OH)₂ solution as activator, it was found that the reaction products formed in cracks are composed of C-S-H, ettringite, hydrogarnet and OH–hydrotalcite. The fraction of C-S-H in the reaction products is much larger than the other minerals. Large amount of ettringite formed in cracks indicates the leaching of SO₄⁻² ions from the bulk paste and consequently the recrystallization. Self-healing proceeds fast within 50 h and then slows down. According to thermodynamic modeling, when the newly formed reaction products are carbonated, the filling fraction of crack increases first and then decreases. Low soluble minerals such as silica gel, gibbsite and calcite are formed. Compared to Portland cement paste, the potential of self-healing in slag cement paste is higher when the percentage of slag is high. Highlights: • Self-healing reaction products in slag cement paste were characterized. • Self-healing reaction products formed in time were quantified with image analysis. • Self-healing in slag cement paste was simulated with a reactive transport model. • Effect of carbonation on self-healing was investigated by thermodynamic modeling. • Effect of slag on self-healing was discussed based on experiments and simulation.

  19. Kinetics of steel slag leaching: Batch tests and modeling

    International Nuclear Information System (INIS)

    Reusing steel slag as an aggregate for road construction requires to characterize the leaching kinetics and metal releases. In this study, basic oxygen furnace (BOF) steel slag were subjected to batch leaching tests at liquid to solid ratios (L/S) of 10 and 100 over 30 days; the leachate chemistry being regularly sampled in time. A geochemical model of the steel slag is developed and validated from experimental data, particularly the evolution with leaching of mineralogical composition of the slag and trace element speciation. Kinetics is necessary for modeling the primary phase leaching, whereas a simple thermodynamic equilibrium approach can be used for secondary phase precipitation. The proposed model simulates the kinetically-controlled dissolution (hydrolysis) of primary phases, the precipitation of secondary phases (C-S-H, hydroxide and spinel), the pH and redox conditions, and the progressive release of major elements as well as the metals Cr and V. Modeling indicates that the dilution effect of the L/S ratio is often coupled to solubility-controlled processes, which are sensitive to both the pH and the redox potential. A sensitivity analysis of kinetic uncertainties on the modeling of element releases is performed.

  20. A study on reduction of copper slag from the flash furnace with the use of anthracite dust

    Directory of Open Access Journals (Sweden)

    G. Siwiec

    2014-07-01

    Full Text Available In the paper, results of a study on reduction of blister copper flash smelting slag with the use of anthracite dust are presented. The material, following proper preparation, can be used for slag processing as a substitute for currently applied coke breeze.

  1. High temperature millimeter wave radiometric and interferometric measurements of slag-refractory interaction for application to coal gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    McCloy, John S.; Crum, Jarrod V.; Sundaram, S. K.; Slaugh, Ryan W.; Woskov, Paul P.

    2011-09-17

    Millimeter wave (MMW) radiometry can be used for simultaneous measurement of emissivity and temperature of materials under extreme environments (high temperature, pressure, and corrosive environments) such as in slagging coal gasifiers, where sensors have been identified as a key enabling technology need for process optimization. We present a state-of-the-art dual-channel MMW heterodyne radiometer with active interferometric capability that allows simultaneous radiometric measurements of sample temperature, emissivity, and flow dynamics to over 1873 K. Interferometric capability is supplied via a probe signal originating from the 137 GHz radiometer local oscillator (LO). The interferometric 'video' channels allow measurement of additional parameters simultaneously, such as volume expansion, thickness change, and slag viscosity along with temperature or emissivity. This capability has been used to demonstrate measurement of temperature and simulated coal slag infiltration into a chromia refractory brick sample as well as slag flow down a vertically placed refractory brick. Observed phenomena include slag melting and slumping, slag reboil and foam with oxygen evolution, and eventual failure of the alumina crucible through corrosion by the molten slag. These results show the promise of the MMW system for extracting quantitative and qualitative process parameters from operating slagging coal gasifiers, providing valuable information for process efficiency, control, and increased productivity.

  2. Utilizing of the metallurgical slag for production of cementless concrete mixtures

    Directory of Open Access Journals (Sweden)

    D. Baricová

    2012-10-01

    Full Text Available In process of pig iron, steel and cast iron production besides main product, also secondary products are formed, that have character of secondary raw materials and industrial wastes. The most abundant secondary product originating in the metallurgical process is furnace slag. Total amount of accured slag, also its chemical, mineralogical, physical – chemical properties and similarity with natural stones predestinate its utilisation in different fields of industry. The contribution deals with production of cementless concrete mixtures, where the main parts were formed by blast furnace granulated slag grinded and different gravel slag from blast furnace, oxygen converter and electric arc furnace. As activators of solidification different kinds of water glass were tested.

  3. 锑精炼除铅渣硝酸浸出回收铅的研究%Study on Lead Recovery from Lead Slag of Antimony Refining by Nitric Acid Leaching Process

    Institute of Scientific and Technical Information of China (English)

    韦岩松; 盘有旺

    2013-01-01

    采用硝酸浸出的方法从锑精炼除铅渣中回收金属铅,考察了液固比、浸出温度和时间、硝酸浓度等对铅浸出率的影响.结果表明,适宜的浸出工艺为:液固比4、浸出温度80℃、浸出时间50 min、硝酸浓度7.0 mol/L.在此条件下,铅浸出率可以达到94%.%Lead was recovered from lead slag of antimony refining by nitric acid leaching process.The effects of ratio of liquid to solid (L/S),leaching temperature and time,and nitric acid concentration on lead leaching rate were investigated.The results show that the lead leaching rate is above 94% under the optimum conditions including L/S of 4,leaching temperature of 80 ℃,leaching time of 50 min,and nitric acid concentration of 7.0 mol/L.

  4. Design of Inorganic Polymer Mortar from Ferricalsialic and Calsialic Slags for Indoor Humidity Control

    OpenAIRE

    Elie Kamseu; Isabella Lancellotti; Sglavo, Vincenzo M.; Luca Modolo; Cristina Leonelli

    2016-01-01

    Amorphous silica and alumina of metakaolin are used to adjust the bulk composition of black (BSS) and white (WSS) steel slag to prepare alkali-activated (AAS) mortars consolidated at room temperature. The mix-design also includes also the addition of semi-crystalline matrix of river sand to the metakaolin/steel powders. The results showed that high strength of the steel slag/metakaolin mortars can be achieved with the geopolymerization process which was particularly affected by the metallic i...

  5. 黄磷炉渣废热利用新工艺与实验研究%New processes and experimental study on yellow phosphorus slag of waste heat utilization

    Institute of Scientific and Technical Information of China (English)

    马立; 魏代晓; 龙恩深; 田向伟

    2013-01-01

    The need for waste heat recovery from molten yellow phosphorus slag is analyzed. The difficulties of yellow phosphorus slag heat recovery are explained in detail. Based on the field investigation, thermal analysis and experimental research,a new designing scheme of slag heat recovering and reuse system in yellow phosphorus slag is provided. The system structure and gain of energy-saving and environmental protection of slag waste heat recovery kiln are introduced and proved.%分析了黄磷炉渣废热回收利用的必要性,详细阐述了黄磷炉渣热回收存在的难点,通过现场调研、热工分析及试验研究,提出了利用炉渣废热回收窑对黄磷炉渣废热进行回收与再利用的新工艺,介绍了该工艺的系统结构,验证了该工艺的节能减排效果.

  6. A Laboratory Study of the Treatability of Synthetic Stormwater Under Varying Conditions Using Electric Arc Furnace Steel Slag

    Directory of Open Access Journals (Sweden)

    Nnaemeka C. Okochi

    2012-03-01

    Full Text Available The investigation of electric arc furnace (EAF steel slag as a viable add-on technology to existing stormwater systems for the removal of dissolved phosphorus (P was extended to explore the effects of varying environmental and treatment system conditions. Parameters such as stormwater composition, P concentration, metal concentration, pH, temperature, slag mass and slag particle size were varied. Observations relating to the method of P removal via EAF slag were also carefully considered to explain removal mechanisms involved. Results demonstrated that, although physisorption contributed to P reduction, it was not the key P removal mechanism. Instead, precipitation was observed to be a key removal pathway as evidenced by the correlation between the loss of iron (Fe from slag and the amount of P removed from solution. The reduced removal of P by slag in a copper-dominant stormwater solution was attributed to the formation of a stable complex formed by the interaction of copper with the slag via the ion-exchange surface model. The stability of this complex inhibits the loss of Fe from the EAF slag and, consequently, P removal by means of precipitation. In terms of the effect of changing environmental and treatment system conditions on the P removal process, stormwater composition, P concentration, metal concentration, pH, temperature, slag mass and slag particle size were found to significantly influence the effectiveness of EAF slag in removing P from a given stormwater system. It was also established that a number of combinations of these factors influence P uptake differently.

  7. The use of blast furnace slag

    Directory of Open Access Journals (Sweden)

    V. Václavík

    2012-10-01

    Full Text Available The paper presents the results of experimental research that dealt with the substitution of finely ground blast furnace slag for Portland cement in the course of simple concrete manufacturing. Physical and mechanical properties of experimental concrete mixtures based on finely ground blast furnace slag were observed.

  8. Amorphous and crystalline blast furnace slag

    International Nuclear Information System (INIS)

    Full text: One of the by-products of iron production from a blast furnace is the slag, Generally 250-300 kg of slag is produced per ton of iron. Liquid blast furnace slag can either be cooled quickly by quenching in a granulator or more slowly in air. The air-cooled product is crushed and sized for use as an aggregate in concrete. The granulated slag is ground to form ground granulated slag, which is a cost-effective supplementary cementitious material. Blends of ground granulated slag and Portland cement produce a cementitious paste that is more resistant to chloride penetration than pastes made from the Portland cement alone. In this study neutron diffraction techniques were used to examine samples of air-cooled and granulated slags from Australian Steel Mill Services stock piles at Port Kembla. Sourced from the same blast furnace, the materials should be expected to posses similar elemental chemistry. The mineral compositions would be different due to the rate of cooling each slag was subjected to. Samples, 15 grams in mass, were mounted in a vanadium can and diffraction patterns were measured using the SLAD instrument on the Reactor R-2 at the Studvik Neutron Research Laboratory in Sweden. The diffraction patterns were transformed into radial distribution functions using the reverse Monte Carlo program, MCGR. The granulated slag showed no diffraction peaks while the air cooled slag showed a crystalline product that can be identified by x-ray diffraction. The radial distribution functions showed differences that were consistent with the granulated slag being amorphous and the air-cooled slag crystalline. Both slag samples showed peaks in the radial distribution function at 1.8 Angstroms and 2.8 Angstroms. The greatest anomaly was a feature about 2.5 Angstroms found only in the radial distribution function for the granulated slag. This demonstration showed that there are differences in the short range bonding between the two compounds. We are currently

  9. Properties of Mortar Incorporating Iron Slag

    Directory of Open Access Journals (Sweden)

    Tamara HUMAM

    2013-11-01

    Full Text Available In the present study effects of replacement of fine aggregate (sand with high percentages of iron slag on the properties of Mortar. Cement mortars of mix proportion 1:3 with incorporating various percentage of iron slag was designed. Fine aggregate were replace with five percentage of iron slag. The percentages of replacements were 0, 10, 20, 30, and 40% by weight of fine aggregate. Tests were performed for compressive strength, split tensile strength, sulphate resistance, Rapid Chloride Permeability Test. Test for all replacement levels of iron slag at different curing periods (7, 28, 56 days . Test result indicates that inclusion of iron slag as partial replacement with fine aggregate enhances the properties of Mortar.

  10. Methods for Improving Volume Stability of Steel Slag as Fine Aggregate

    Institute of Scientific and Technical Information of China (English)

    LUN Yunxia; ZilOU Mingkai; CAI Xiao; XU Fang

    2008-01-01

    Suitable methods for enhancing the volume stability of steel slag utilized as fine aggregate were determined. The effects of steam treatment at 100 ℃ and autoclave treatment under 2.0 Mpa on the soundness of steel slag sand were investigated by means of powder ratio, linear expansion, compressive and flexural strength. DTA, EDX, XRD and ethylene glycol methods were employed to analyze both the treated slags and susceptible expansion grains. Experimental results indicate that powder ratio, content of free lime and rate of linear expansion can express the improvement in volume stability of different treated methods. Steam treatment process cannot ultimately prevent specimens from cracking and decrease of strength, but mortar made from autoclave treated slag keeps integration subjected to hot water of 80 ℃ until 28 d and its strength do not show significant decrement. The hydration of over-burn free lime and periclase phase are the main cause for the disintegration or crack of untreated and steam treated steel slag's specimens. Autoclave treatment process is more effective than steam treatment process on enhancement of volume stability of steel slag.

  11. Laser-flash method for determining thermal diffusivity of blast furnace slags and burden materials

    Energy Technology Data Exchange (ETDEWEB)

    Gudenau, H.W.; Rademacher, P.K.; Lindner, K.H.

    1983-01-01

    22% of the total costs have to be paid nowadays for energy in the steel production according to the conventional process (blast furnace route). 66% of the total energy consumption is used for the blast furnace, which is the main energy consumer in a steel plant. The thermal diffusivity measurement of burden materials gives important data for the critical examination of the heat transport inside the blast-furnace. BF-slags (1450-1550/sup 0/C) represent the waste heat potential with the highest temperature level. The thermal diffusivity therefore is of special interest in carrying out thermal calculations on the heat recovery of BF-slags. Thermal diffusivities of BF-slags with different porosity, unreduced pellets and coke were measured using the laser-flash-method. Blast furnace slags have very low thermal diffusivity values similar to refractories and BF-linings.

  12. Leaching characteristics of steel slag components and their application in cementitious property prediction.

    Science.gov (United States)

    Li, Zaibo; Zhao, Sanyin; Zhao, Xuguang; He, Tusheng

    2012-01-15

    High-efficiency recovery and utilization of steel slag are important concerns for environmental protection and sustainable development. To establish a rapid method to evaluate the cementitious properties of steel slag, leaching tests were carried out on steel slag components via an evaporation-condensation method; the leaching characteristics and mechanism of the slag were also investigated. The relationship between leaching characteristics and cementitious properties, which were represented by mortar compressive strength, was analyzed. Results show that there exist significant differences among the amounts of chemically active leached components. The leaching process can be described by the shrinking unreacted core model controlled by intra-particle diffusion, and is in accordance with Kondo R hydration kinetics equation. The leaching process showed a good linear relationship between the amounts of components leached from steel slag and the mortar compressive strength of cementitious materials prepared from reference cement and steel slag with mass ratios of 50:50 and 70:30. The compressive strengths of mortars subjected to 7, 28, and 90 days of curing can be accurately predicted by the sum of leached (CaO+Al(2)O(3)) obtained after a certain length of leaching time. PMID:22088502

  13. A Brief Review of Viscosity Models for Slag in Coal Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Massoudi, Mehrdad; Wang, Ping

    2011-11-01

    Many researchers have defined the phenomenon of 'slagging' as the deposition of ash in the radiative section of a boiler, while 'fouling' refers to the deposition of ash in the convective-pass region. Among the important parameters affecting ash deposition that need to be studied are ash chemistry, its transport, deposit growth, and strength development; removability of the ash deposit; heat transfer mechanisms; and the mode of operation for boilers. The heat transfer at the walls of a combustor depends on many parameters including ash deposition. This depends on the processes or parameters controlling the impact efficiency and the sticking efficiency. For a slagging combustor or furnace, however, the temperatures are so high that much of the coal particles are melted and the molten layer, in turn, captures more particles as it flows. The main problems with ash deposition are reduced heat transfer in the boiler and corrosion of the tubes. Common ways of dealing with these issues are soot blowing and wall blowing on a routine basis; however, unexpected or uncontrolled depositions can also complicate the situation, and there are always locations inaccessible to the use of such techniques. Studies have indicated that slag viscosity must be within a certain range of temperatures for tapping and the membrane wall to be accessible, for example, between 1300 C and 1500 C, the viscosity is approximately 25 Pa {center_dot} s. As the operating temperature decreases, the slag cools and solid crystals begin to form. In such cases the slag should be regarded as a non-Newtonian suspension, consisting of liquid silicate and crystals. A better understanding of the rheological properties of the slag, such as yield stress and shear-thinning, are critical in determining the optimum operating conditions. To develop an accurate heat transfer model in any type of coal combustion or gasification process, the heat transfer and to some extent the rheological properties

  14. Effect of MgO and MnO on Phosphorus Utilization in P-Bearing Steelmaking Slag

    Science.gov (United States)

    Lin, Lu; Bao, Yan-Ping; Wang, Min; Li, Xiang

    2016-04-01

    In order to recycle the phosphorus in P-bearing converter slag and make it used as slag phosphate fertilizer, the effect of MgO and MnO in P-bearing steelmaking slag on phosphorus existence form, P2O5 solubility and magnetic separation behavior were researched systematically. The results show that the phosphorus in slag is mainly in the form of n2CaO · SiO2-3CaO · P2O5 (for short nC2S-C3P) solid solution in the P-rich phase for CaO-SiO2-FetO-P2O5-X (X stands for MgO and MnO, respectively). And the increasing of MgO and MnO content has no influence on precipitation of nC2S-C3P solid solution in slag, MnO and MgO mainly enter into RO phase and base phase to form MnFe2O4 and MgFe2O4, which has little effect on the P2O5 content of P-rich phase, so which has little effect on the degree of phosphorus enrichment and phosphorus occurrence form of the P-bearing slag. And adding MgO and MnO into CaO-SiO2-P2O5-Fe2O3 slag system can break the complex net structure formed by Si-O on certain degree, and also hinder the precipitation of β-Ca3(PO4)2 crystal with low citric acid solubility during the melting-cooling process. Therefore, adding appropriate MgO and MnO content into slag can improve the slag P2O5 solubility, but the effect of different amounts of MgO and MnO on the P2O5 solubility has little difference. Meanwhile, adding MgO and MnO into slag can improve the metallization of slag and magnetism of iron-rich phase, make the magnetic substances content increase and separation of phosphorus and iron incomplete, so it is adverse to phosphorus resources recovery from P-bearing slag by magnetic separation method. In order to recycle the phosphorus in P-bearing converter slag, the MgO and MnO content in the P-bearing slag should be controlled in the steelmaking process.

  15. Research and development plan for the Slagging Pyrolysis Incinerator

    International Nuclear Information System (INIS)

    Objective is to develop an incinerator for processing disposed transuranium waste. This R and D plan describes the R and D efforts required to begin conceptual design of the Slagging Pyrolysis Incinerator (Andco-Torrax). The program includes: incinerator, off-gas treatment, waste handling, instrumentation, immobilization analyses, migration studies, regulations, Belgium R and D test plan, Disney World test plan, and remote operation and maintenance

  16. Coexistence Theory of Slag Structure and Its Application to Calculation of Oxidizing Capability of Slag Melts

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The coexistence theory of slag structure and it's application to calculation of the oxidizing capabilities of slag melts is described. It is shown that the law of mass action can be widely applied to the calculation of oxidizing capabilities of slag melts in combination with the coexistence theory of slag structure.For slag melts containing basic oxides FeO and MnO, their oxidizing capabilities can be expressed by NFetO=NFeO+6NFe2O3, while for slag melts containing basic oxides CaO, MgO, etc., in addition to FeO and MnO, their oxidizing capabilities can be given as NFetO=NFeO+6NFe2O3+8NFe3O4.

  17. ASPEN Plus simulation of coal integrated gasification combined blast furnace slag waste heat recovery system

    International Nuclear Information System (INIS)

    Highlights: • An integrated system of coal gasification with slag waste heat recovery was proposed. • The goal of BF slag heat saving and emission reduction was achieved by this system. • The optimal parameters were obtained and the waste heat recovery rate reached 83.08%. • About 6.64 kmol/min syngas was produced when using one ton BF slag to provide energy. - Abstract: This article presented a model for the system of coal gasification with steam and blast furnace slag waste heat recovery by using the ASPEN Plus as the simulating and modeling tool. Constrained by mass and energy balance for the entire system, the model included the gasifier used to product syngas at the chemical equilibrium based on the Gibbs free energy minimization approach and the boiler used to recover the heat of the blast furnace slag (BF slag) and syngas. Two parameters of temperature and steam to coal ratio (S/C) were considered to account for their impacts on the Datong coal (DT coal) gasification process. The carbon gasification efficiency (CE), cold gasification efficiency (CGE), syngas product efficiency (PE) and the heating value of syngas produced by 1 kg pulverized coal (HV) were adopted as the indicators to examine the gasification performance. The optimal operating temperature and S/C were 800 °C and 1.5, respectively. At this condition, CE reached above 90% and the maximum values of the CGE, PE and HV were all obtained. Under the optimal operating conditions, 1000 kg/min BF slag, about 40.41 kg/min DT pulverized coal and 77.94 kg/min steam were fed into the gasifier and approximate 6.64 kmol/min syngas could be generated. Overall, the coal was converted to clean syngas by gasification reaction and the BF slag waste heat was also recovered effectively (reached up to 83.08%) in this system, achieving the objective of energy saving and emission reduction

  18. Chemical and mineralogical characterizations of LD converter steel slags: A multi-analytical techniques approach

    International Nuclear Information System (INIS)

    The use of LD converter steel slags (coming from Linz-Donawitz steelmaking process) as aggregates in road construction can in certain cases lead to dimensional damage due to a macroscopic swelling that is the consequence of chemical reactions. The aim of this study was to couple several analytical techniques in order to carefully undertake chemical and mineralogical characterizations of LD steel slags and identify the phases that are expected to be responsible for their instability. Optical microscopy, scanning electron microscopy and electron probe microanalyses revealed that LD steel slags mainly contain calcium silicates, dicalcium ferrites, iron oxides and lime. However, as a calcium silicate phase is heterogeneous, Raman microspectrometry and transmitted electron microscopy had to be used to characterize it more precisely. Results showed that lime is present under two forms in slag grains: some nodules observed in the matrix whose size ranges from 20 to 100 μm and some micro-inclusions, enclosed in the heterogeneous calcium silicate phase whose size ranges from 1 to 3 μm. It was also established that without the presence of magnesia, lime is expected to be the only phase responsible for LD steel slags instability. Nevertheless, the distribution of lime between nodules and micro-inclusions may play a major role and could explain that similar amounts of lime can induce different instabilities. Thus, it appears that lime content of LD steel slags is not the only parameter to explain their instability.

  19. Treatment of industrial lead and zink slags in a pilot scale SAF

    Energy Technology Data Exchange (ETDEWEB)

    Boehlke, J.; Friedrich, B. [IME Metallurgical Process Technology and Metal Recycling, Aachen (Germany); Hecker, E. [SMS Demag AG, Duesseldorf (Germany)

    2005-08-01

    In the course of the pyrometallurgical production of lead and zinc it is unavoidable that significant amounts of those metals are contained in the slags which are produced as a by-product. These contents of lead and zinc in the slags lead to a decrease in yield and in the economy of the production and present a latent danger to the environment. Therefore, the treatment of these slags in a submerged arc furnace aiming at the recovery of zinc and lead and production of a useable slag is being investigated at the IME Process Metallurgy and Metal Recycling in project which is financed by the German Federal Ministry of Education and Research. The investigations conducted include chemical analysis, thermodynamic modelling and experimental test work in a laboratory scale submerged arc furnace and a pilot scale submerged arc furnace. The aim of the project is to produce slags which can be utilised in further applications instead of having to be dumped, and at the same time increasing the efficiency of the lead and zinc operation by recovering lead and zinc from the slags. (orig.)

  20. Simulation of Frozen Slag Inside Brickless Reaction Shaft of Flash Smelting Furnace

    Science.gov (United States)

    Wang, Jinliang; Wang, Houqing; Tong, Changren; Zhang, Wenhai; Zhang, Chuanfu

    2013-12-01

    Based on the principle of heat transfer, a three-dimensional model of frozen slag in the brickless reaction shaft of a flash smelting furnace was established by computing the temperature field and judging the moving boundary. In the modeling process, a cylindrical coordinate system was adopted to specify the point positions according to the geometry of the brickless reaction shaft, and an improved method was proposed to discretize the three-dimensional control equations. The model was then applied to investigate the influence of the operational [gas temperature (GT), cooling water temperature (CWT), and melting temperature of frozen slag (MTFS)] and structural (steel shell thickness, steel nail thickness, steel nail length, and distance between nails) parameters on the thickness of the frozen slag. The results showed that the GT, CWT, and MTFS have a marked impact on the thickness of frozen slag, which decreases at high temperature and increases when cooled; the structural parameters have little effect on the thickness of frozen slag in terms of heat transfer. Consequently, to form a layer of frozen slag with a desired thickness inside a brickless reaction shaft, it is important to avoid localized ultra-high temperatures in the inner chamber and to cool the steel shell using a strong flow of low-temperature water; mechanical (and not thermal) factors should take precedence when designing the steel nails of a brickless reaction shaft.

  1. Adsorption Study of Electric Arc Furnace Slag for the Removal of Manganese from Solution

    Directory of Open Access Journals (Sweden)

    C. L. Beh

    2010-01-01

    Full Text Available Problem statement: Steel making slag from Electric Arc Furnace (EAF is an abundant by-product in Malaysia steel making industry. It has potential to be used for heavy metal removal from contaminated water or waste water. Approach: The aim of this study was to investigate the characteristic and behavior of manganese removal by using EAF slag for efficient metal removal. The removal characteristics of manganese were investigated in term of sorption kinetics and isotherm. The batch adsorption kinetics and isotherm studies were carried out at 28°C and ten grams of EAF slag was added into 1 L manganese solution of various concentrations of 10, 25, 50, 75, 100 and 120 mg L-1. All these different mixtures were stirred and sampled at various desired times and centrifuged. The supernatant solutions were then collected for chemical analysis. Results: It was found that the EAF slag adsorption kinetics can be described well by the pseudo-2nd order kinetic model with fairly high correlation coefficients. The adsorption process obeyed the Langmuir isotherm model and the maximum uptake of the manganese from the solution is 2.31 mg L-1 g-1 of EAF slag used. Conclusion: From the study, it was concluded that the EAF slag can be an efficient adsorbent to remove manganese from both the solution and waste water.

  2. Thermodynamic Properties of Lead Oxide in a Mixture of Stainless Steelmaking and Nonferrous Smelting Slags

    Science.gov (United States)

    Maruoka, Nobuhiro; Ueda, Shigeru; Shibata, Hiroyuki; Yamaguchi, Katsunori; Kitamura, Shin-ya

    2012-06-01

    In our previous paper, a slag modification process involving the mixing of stainless steelmaking and nonferrous smelting slags was proposed for preventing the disintegration of the stainless steelmaking slag. In order to use this method, the behavior of heavy metals especially PbO contained in the nonferrous slag has to be assessed. In the present study, the activity coefficient of PbO in CaO-SiO2-FetO-Al2O3-MgO and CaO-SiO2-FetO slags saturated with iron was measured at 1673 K. The results showed that the activity coefficient of PbO increased with basicity and had a maximum value when the basicity was approximately 1.0. The equilibrium PbO content in the modified slag had a minimum value that corresponded to a mixing ratio of 0.6. The trend was similar to the change in the removal ratio of PbO observed in the previous study. Therefore, the change in the oxygen potential and the change in the activity coefficient of PbO can be considered the cause of this trend.

  3. Effect of Superfine Slag Powder on HPC Properties

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A superfine slag powder (SP) made from granulated blast furnace slag incorporating activators by using special millingtechnique, was used as supplementary cementitious material in high performance concrete (HPC), replacing part ofthe mass of normal Portland cement. The effects of the SP on the workability, mechanical and crack self-healingproperties of HPC were studied. The hydration process and microstructure characteristics were investigated by X-raydiffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. The crack self-healing capacitywas evaluated by Brazilian test. The test results indicate that the SP has especially supplementary effect on waterreducing and excellent property of better control of slump loss. The concrete flowability increases remarkably withthe increase of SP replacement level in the range of 20% to 50%. The compressive and splitting tensile strengthsof HPC containing SP are higher than the corresponding strength of the control concrete at all ages. The crackself-healing ability is highly dependent on SP content of HPC.

  4. Application of Improved HMM Algorithm in Slag Detection System

    Institute of Scientific and Technical Information of China (English)

    TAN Da-peng; LI Pei-yu; PAN Xiao-hong

    2009-01-01

    To solve the problems of ladle slag detection system (SDS),such as high cost,short service life,and inconvenient maintenance,a new SDS realization method based on hidden Markov model (HMM) was put forward.The physical process of continuous casting was analyzed,and vibration signal was considered as the main detecting signal according to the difference in shock vibration generated by molten steel and slag because of their difference in density.Automatic control experiment platform oriented to SDS was established,and vibration sensor was installed far away from molten steel,which could solve the problem of easy power consumption by the sensor.The combination of vector quantization technology with learning process parameters of HMM was optimized,and its revaluation formula was revised to enhance its recognition effectiveness.Industrial field experiments proved that this system requires low cost and little rebuilding for current devices,and its slag detection rate can exceed 95 %.

  5. Digested sewage sludge solidification by converter slag for landfill cover.

    Science.gov (United States)

    Kim, Eung-Ho; Cho, Jin-Kyu; Yim, Soobin

    2005-04-01

    A new technology for solidification of digested sewage sludge referred to as converter slag solidification (CSS) has been developed using converter slag as the solidifying agent and quick lime as the solidifying aid. The CSS technology was investigated by analyzing the physicochemical properties of solidified sludge and determining its microstructural characteristics. The feasibility of using solidified sludge as a landfill cover material was considered in the context of the economical recycling of waste. Sludge solidified using the CSS technology exhibited geotechnical properties that are appropriate for replacing currently used cover soil. Microscopic analyses using XRD, SEM and EDS revealed that the main hydrated product of solidification was CSH (CaO . SiO2 . nH2O), which may play an important role in the effective setting process. Negligible leaching of heavy metals from the solidified sludge was observed. The solidification process of the hydrated sludge, slag and quicklime eliminated the coliform bacteria. Recycled sewage sludge solidified using CCS technology could be used as an effective landfill cover. PMID:15763091

  6. Experimental investigation on ligament formation for molten slag granulation

    International Nuclear Information System (INIS)

    During the dry granulation for molten blast furnace slag, rotary cup is used to atomize the molten slag. In this study, the mechanism of ligament formation for molten slag granulation was investigated. The results indicated that the transition equations from direct drop formation to ligament formation and ligament formation to sheet formation, obtained from glycerol/water mixture, can identify the type of disintegration for molten blast furnace slag granulation. Due to short wavelength of dilational wave along molten slag ligaments, the diameter of slag particles decreased with an increase in angular speed, and more and more slag particles were far away from the center of rotary cup. The slag particles diameter decreased with an increase in rotary cup diameter. The empirical equation can be used to predict the diameter of slag particles obtained by ligament formation for molten slag granulation at high angular speed. Because of slight change in viscosity and surface tension when the temperature of molten slag was over than 1300 °C, there was no change in diameter and mass fraction of slag particles with an increase in molten slag temperature. All the results could provide guidance for the design of industrial plant for molten blast furnace slag granulation. - Highlights: • Dry granulation for molten blast furnace slag is an attractive alternative to wet granulation. • Transition equation can be used to identify state of disintegration for molten slag granulation. • The diameter of slag particles decreased as an increase in angular speed and diameter of rotary cup. • There was no change in diameter of slag particles with an increase in molten slag temperature

  7. Heat-resistant ferrochrome slag based concrete

    OpenAIRE

    M.T. Zuginisov; M.M. Myrzahmetov; D.T. Sartayev; Ye.S. Orynbekov

    2014-01-01

    In the construction materials industry, expensive refractories (fire clay, silica, high- aluminous, etc.), are used as the main lining materials which despite their high fire resistance are inefficient for the use in thermal aggregates with an operation temperature up to 1300 °C. The purpose of the research was to develop heat-resistant concrete on the basis of sodium silicate binder and liquid glass with application of ferrochrome slag. Studies on the use of ferrochrome slag to obtain h...

  8. Dissolution of alumina in stainless steelmaking slags

    Energy Technology Data Exchange (ETDEWEB)

    Divakar, M.; Lahiri, A.K. [Indian Inst. of Science, Bangalore (India). Dept. of Metallurgy; Goernerup, M. [Uddeholm Technology AB (Sweden)

    2001-02-01

    Dissolution of alumina in stainless steelmaking slags was studied by conducting laboratory scale experiments on typical slags in the temperature range 1823-1923 K. The mechanism of dissolution was studied under the actual steelmaking conditions where several phenomena such as simultaneous reduction of chromium, iron and vanadium oxides by carbon, in-situ gas generated due to the reduction, foam/emulsion formation occur. The kinetics of alumina dissolution are studied under the influence of the above mentioned phenomena. (orig.)

  9. The use of blast furnace slag

    OpenAIRE

    Václavík, Vojtěch; Dirner, Vojtech; Dvorský, Tomáš; Daxner, J.

    2012-01-01

    The paper presents the results of experimental research that dealt with the substitution of fi nely ground blast furnace slag for Portland cement in the course of simple concrete manufacturing. Physical and mechanical properties of experimental concrete mixtures based on fi nely ground blast furnace slag were observed. Rad predstavlja rezultate eksperimentalnog istraživanja koja se bave mogućnostima primjene fi nozrnate troske iz visoke peći za Portland cement u jednostavnoj proiz...

  10. Evaluation of novel reactive MgO activated slag binder for the immobilisation of lead and zinc.

    Science.gov (United States)

    Jin, Fei; Al-Tabbaa, Abir

    2014-12-01

    Although Portland cement is the most widely used binder in the stabilisation/solidification (S/S) processes, slag-based binders have gained significant attention recently due to their economic and environmental merits. In the present study, a novel binder, reactive MgO activated slag, is compared with hydrated lime activated slag in the immobilisation of lead and zinc. A series of lead or zinc-doped pastes and mortars were prepared with metal to binder ratio from 0.25% to 1%. The hydration products and microstructure were studied by X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. The major hydration products were calcium silicate hydrate and hydrotalcite-like phases. The unconfined compressive strength was measured up to 160 d. Findings show that lead had a slight influence on the strength of MgO-slag paste while zinc reduced the strength significantly as its concentration increased. Leachate results using the TCLP tests revealed that the immobilisation degree was dependent on the pH and reactive MgO activated slag showed an increased pH buffering capacity, and thus improved the immobilisation efficiency compared to lime activated slag. It was proposed that zinc was mainly immobilised within the structure of the hydrotalcite-like phases or in the form of calcium zincate, while lead was primarily precipitated as the hydroxide. It is concluded, therefore, that reactive MgO activated slag can serve as clinker-free alternative binder in the S/S process. PMID:25123653

  11. 结晶器渣圈对渣道压力、振痕及渣耗影响的分析%Analysis on Influences of Mold Slag Rim on Channel Pressure, Oscillation Marks and Slag Consumption

    Institute of Scientific and Technical Information of China (English)

    孟祥宁; 汪宁; 朱苗勇

    2015-01-01

    对比分析了三种类型结晶器渣圈,阐明了渣圈对连铸坯生产过程的影响。结果表明,当渣圈存在时,渣道动态压力变化幅度显著增大,最大正压由1.373 kPa提高到21 kPa,压力增大导致振痕产生,渣圈越厚,振痕越深;同时,渣圈会影响保护渣的消耗量,无渣圈时,最大渣耗量为0.0097 kg/(m.s),渣圈存在时,最大渣耗量降至0.007 kg/(m.s),较厚的渣圈会使渣道宽度变窄,在振动负滑脱中期降低保护渣的消耗量。%The influences of slag rim on the process of continuous casting strand production were explained based on the comparative analysis of three different types of mold slag rims. The results show that when slag rim was used, the amplitude of variation of the dynamic channel pres-sure changed significantly, indicating that the maximum positive pressure increased to 21 kPa from 1.373 kPa, which caused the oscillating marks and the thicker the slag rim was, the deeper the os-cillating marks would be. At the same time, slag rim would have influence on consumption of the slag. When slag rim was not used, the maximum consumption of slag was about 0.009 7 kg/(m.s) while slag rim was used, the maximum consumption of slag was decreased to 0.007 kg/(m.s). And also thicker slag rim would make the width of slag channel narrow down, which would cut down the consumption of slag during the metaphase of negative strip time in oscillation.

  12. Acid slag injection into the blast furnace tuyere zone

    Energy Technology Data Exchange (ETDEWEB)

    Haerkki, J.; Tervola, K. [Oulu Univ. (Finland). Dept. of Process Engineering

    1996-12-31

    The possibility of acid slag injection and its effect on the slag formation and on the melting behaviour of the charge materials are studied in the present work. The work is partly based on the literature evaluating the slag formation, slag properties and the basic slag injection. The possibility of acid slag injection is first examined by studying changes in the composition of the primary slag if the share of the acid slag component (Kostamus pellet/RR) of the charge material is lowered. Phase diagrams and viscosity charts are used to evaluate the viscosity, and solidus/liquidus temperature in the slag phase. The share of the slag phase of the pellet is evaluated by calculating the amount of the acid slag injection. The injection rate of some injectants is also examined. The primary slag formed of the sinter and the coke ash is in liquid form and its viscosity is close to the viscosity of the blast furnace slag. It is possible that the liquid slag phase can be formed in the blast furnace without the presence of the acid pellet because the melting point and the viscosity of the slag is lowered by alkalies, sulfur and the dissolved ironoxide of the slag. If high SiO{sub 2} content materials alone are used for injection there is a risk that the slag phase of the tuyere zone becomes too viscous. Olivine and some iron containing components such as fayalite are possible injection material. More information is needed to evaluate the effect of acid slag injection on the operation of the blast furnace. (orig.) SULA 2 Research Programme; 2 refs.

  13. Recycling of the rare earth oxides from spent rechargeable batteries using waste metallurgical slags

    Directory of Open Access Journals (Sweden)

    Tang K.

    2013-01-01

    Full Text Available A high temperature process for recycling spent nickel-metal hydride rechargeable batteries has been recently developed at SINTEF/NTNU. The spent battery modules were first frozen with liquid nitrogen for the de-activation and brittle fracture treatment. The broken steel scraps and plastics were then separated by the mechanical classification and magnetic separation. The remaining positive and negative electrodes, together with the polymer separator, were heated to 600-800oC in order to remove the organic components and further separate the Ni-based negative electrode. XRF analyses indicate that the heat-treated materials consist mainly of nickel, rare earth and cobalt oxides. The valuable rare earth oxides were further recovered by the high-temperature slagging treatment. The waste metallurgical slags, consist mainly of SiO2 and CaO, were used as the rare earth oxide absorbent. After the high temperature slagging treatment, over 98% of nickel and cobalt oxides were reduced to the metal phase; meanwhile almost all rare earth oxides remain in the molten slags. Furthermore, EPMA and XRF analyses of the slag samples indicate that the rare earth oxides selectively precipitate in the forms of solid xSiO2•yCaO•zRe2O3. The matrix of slag phase is Re2O3 deficient, typically being less than 5 wt%. This provides a sound basis to further develop the high-temperature process of concentrating the Re2O3 oxides in slags.

  14. Research on slag steam generator: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Jablin, R.

    1987-12-01

    A substantial effort has been made to conclude a contract for a large-scale SSG unit to be installed adjacent to a blast furnace. This effort has been unsuccessful during the time period of this contract for two reasons which are described in detail. A potential application for installation of the SSG has been investigated for the electric arc furnaces at Nucor Steel Company in Darlington, South Carolina. This application has several advantages but Nucor is currently bringing on line two major new technologies in steelmaking and the company is unable to devote additional man hours to the SSG process. Because of these other commitments, further investigation by Nucor will be held in abeyance until 1988. Contractural arrangements to license the SSG press has been sought with Paul Wurth Cy. and with Nippon Kokan K.K. Wurth has put the project in abeyance and response from Nippon Kokan is still forthcoming. Negotiations with both companies will be reopened in 1988. A potential application which relates to the DOE project for a coal-fired, gas turbine has been discovered for the SSG process. It appears that consideration of slag handling will probably take place in about two years, at which time further contacts will be made with them. Richard Jablin and Associates plans to continue work on this project without seeking further financial support from the DOE, or from another federal agency.

  15. Recovery of uranium and lining material from magnesium fluoride slag at UMP

    International Nuclear Information System (INIS)

    At Uranium Metal Plant, uranium metal is produced by reduction of UF4 with magnesium metal, in a closed reactor lined with refractory MgF2 lining material. During this reduction, more MgF2 is produced as the slag. This slag generally contains 2-4% uranium and hence is processed to recover these values and part of the slag, free from uranium is reused for lining the reactor. This paper describes the process parameters finalised for crushing and grinding of the slag and for leaching uranium with nitric acid. The leach liquor contains appreciable amount of fluoride and hence is processed through a separate solvent extraction cycle with tributyl phosphate. The resultant purified uranyl nitrate solution is mixed with the main stream crude solution for final purification. The conditions optimised for the solvent extraction step, the problems faced during the regular operation over the last few years and the experience gained are described. An outline of the scheme to treat larger quantities of the slag on a regular basis is presented. (author). 6 refs., 1 fig., 1 tab

  16. THE INFLUENTIAL FACTOR ANALYSIS ON COPPER RECOVERY OF SMELTING SLAG GRINDING FLOTATION PROCESS%影响熔炼炉渣磨浮工艺回收铜的因素分析

    Institute of Scientific and Technical Information of China (English)

    曲胜利; 李天刚; 董准勤

    2012-01-01

    The complex copper concentrate with high gold and silver content is treated by oxygen-enriched bottom-blowing melting technique of matte gold catcher. Controlling the slag type of smelting slag, selecting the appropriate cooling method and optimize crushing- grinding conditions have been adopted to increase the recovery rate of copper. This paper, combines with the production practice and trial, leads a deeper research and analysis on this question as well.%采用富氧底吹熔炼技术造锍捕金技术,处理Au,Ag含量较高的复杂铜精矿.通过控制熔炼渣的渣型、选择合适的冷却方式、优化破碎—细磨条件来提高铜的回收率,并结合生产实践及试验对其进行研究与分析.

  17. Investigation of Copper Losses to Synthetic Slag at Different Oxygen Partial Pressures in the Presence of Colemanite

    Science.gov (United States)

    Rusen, Aydın; Derin, Bora; Geveci, Ahmet; Topkaya, Yavuz Ali

    2016-05-01

    Copper losses to slag are crucial for copper matte smelting and converting stages. One factor affecting the copper losses to slag during these processes is partial pressure of oxygen. In this study, theoretical and experimental investigations of oxygen partial pressure effect on copper losses to fayalite type slag in the presence of colemanite were investigated. Theoretical considerations include liquidus temperatures and phase diagrams of the fayalite type slag calculated by the FactSage software program. In the experiments, a synthetic matte-slag (SM-SS) was produced by melting certain amounts of reagent grade Fe2O3-SiO2 and metallic Fe as starting materials. Experiments were carried out with SM-SS pair by the addition of calcined colemanite (from 0% to 6%) under various partial pressures of oxygen (10-7, 10-9, 10-11 atm) at 1250°C for 2 h. From the experimental results, it was found that the amount of copper in slag decreased slowly when colemanite was increased under all oxidizing atmospheres. The lowest copper content in synthetic slag was obtained as 0.38% after 6% colemanite addition.

  18. Further studies on developing technology for indirect liquefaction

    Science.gov (United States)

    Gray, D.; Neuworth, M. B.; Tomlinson, G.

    1982-03-01

    Our investigations have resulted in the conclusion that fluidized gasifiers, such as Westinghouse or entrained flow gasifiers such as Texaco and Shell-Koppers offer significant advantages over the BGC Lurgi gasifier when Illinois No. 6 coal is employed as the feedstock. Dry-ash Lurgi gasification has additional disadvantages which appear to make it unsuitable for applications with mildly caking coal such as Illinois No. 6. The results of our analyses of Illinois No. 6 coal do not alter our prior conclusions regarding the use of advanced gasification systems for indirect liquefaction. BGC/Lurgi, Westinghouse, Texaco and Shell-Koppers gasifiers offer significant advantages over dry-ash Lurgi and should be given detailed consideration for a US liquefaction facility. The final decision will probably be driven by the relative state of development at the time a decision is required, process license and guarantees which could be negotiated, the market value of an SNG co-product, and the specific characteristics of the coal feedstock to be used.

  19. Geological Sequestration of CO2 by Hydrous Carbonate Formation with Reclaimed Slag

    Energy Technology Data Exchange (ETDEWEB)

    Von L. Richards; Kent Peaslee; Jeffrey Smith

    2008-02-06

    The concept of this project is to develop a process that improves the kinetics of the hydrous carbonate formation reaction enabling steelmakers to directly remove CO2 from their furnace exhaust gas. It is proposed to bring the furnace exhaust stream containing CO2 in contact with reclaimed steelmaking slag in a reactor that has an environment near the unit activity of water resulting in the production of carbonates. The CO2 emissions from the plant would be reduced by the amount sequestered in the formation of carbonates. The main raw materials for the process are furnace exhaust gases and specially prepared slag.

  20. ENHANCEMENT OF STRUCTURAL FOAM MATERIALS BY INCORPORATION OF GASIFIER SLAG

    Energy Technology Data Exchange (ETDEWEB)

    Olin Perry Norton; Ronald A. Palmer; W. Gene Ramsey

    2006-03-15

    As advanced gasification technology is increasingly adopted as an energy source, disposal of the resulting slag will become a problem. We have shown that gasifier slag can be incorporated into foamed glass, which is currently being manufactured as an abrasive and as an insulating material. The slag we add to foamed glass does not simply act as filler, but improves the mechanical properties of the product. Incorporation of gasifier slag can make foamed glass stronger and more abrasion resistant.

  1. Chromium reduction from slag on electromelting of stainless steel

    International Nuclear Information System (INIS)

    Specific features of chromium reduction from the slag on electromelting of stainless steel type Kh18N10T according to one- or two-slag procedure were studied. It was shown that one-slag melting technology allows double decrease of chromium losses in the form of incompletely reduced oxides. This occurs due to additional chemical reactions between metal and slag on their combined pouring into the ladle. 1 ref.; 3 figs

  2. Slag Corrosion Resistace of β-Sialon-Al2O3 Composites-Part I. Thermodynamics and Mechanism

    Institute of Scientific and Technical Information of China (English)

    LIYoufeng; HONGYanruo; 等

    2001-01-01

    Slag corrosion resistance of β-Sialon and β-Sialon-Al2O3 composites has been studied .The effects of FeO content and temperature on corrosion rate have been investi-gated by mens of dip method(static and self-rotating).The corrosion process and microstructural analysis.It is shown that FeO preferentially attacks β-Sialon in the composite and the protruded corundum grains would gradualy fall off into the slag.

  3. Analysis of Cr with various valence states in industrial EAF slag for making stainless steel

    International Nuclear Information System (INIS)

    Slags of stainless steel making by EAF process in one plant from south and the other from north China were selected. The qualitative and quantitative analysis of all elements in samples were investigated first, the possible phases were identified by diffraction. Micro-morphology and composition analysis showed that Cr exist in iron-based alloy, chromite phase and Cr-containing silicate phase. It inferred that Cr (0) would be in iron-based alloy drops, Cr (III) would be in chromite phase. The Cr valence states in slag were assumed as 0, +2, +3 and +6. The caustic plus carbonate sodium solution was adopted to leach Cr (VI) as CrO42-; oxalic acid was applied to leach the Cr (0) in alloy drops; FeCl3-HCl-NH4Cl combined with V2+-HCl leaching process, the Cr (II) in slag would change to Cr2+ in solution; the resident containing Cr (III) was smelting by Na2O2. Cr in different valence states were separated and detected. The optimized leaching processes of Cr (VI) and Cr (0) were investigated. The influence of the leaching process on existence of other phase was checked also. The analysis results showed the route of separation and analysis is suitable for the slag samples. Both slag samples were with the same trend of contents in various Cr states. Among the states, Cr (0) content is highest, about 2.0-4.5 mass%; the second highest content is Cr (III), about 1.4-2.7 mass%; the content of toxic Cr (VI) is about 80-310 ppm, the lest one is Cr (II), about 1.0-2.1 ppm. This study would provide an experimental method and basis for the utilization and environmental impact of stainless steel smelting slag. (author)

  4. Characterization study of heavy metal-bearing phases in MSW slag.

    Science.gov (United States)

    Saffarzadeh, Amirhomayoun; Shimaoka, Takayuki; Motomura, Yoshinobu; Watanabe, Koichiro

    2009-05-30

    Slag products derived from the pyrolysis/melting and plasma/melting treatment of municipal solid waste (MSW) in Japan were examined for the characterization study of heavy metal-bearing phases using petrographic techniques. Detailed microscopic observations revealed that the shapes of heavy metal-rich inclusions are generally spherical to semi-spherical and their sizes range from submicron to scarcely large size spheres (over 100 microm). The experiments (both optical microscopy and electron probe microanalysis) indicated that Fe and Cu participate in mutual substitution and different proportions, and form mainly two-phase Fe-Cu alloys that bound in the silicate glass. This alloy characterizes the composition of more than 80% of the metal-rich inclusions. Other metals and non-metals (such as Pb, Ni, Sb, Sn, P, Si, Al and S) with variable amounts and uneven distributions are also incorporated in the Fe-Cu alloy. In average, the bulk concentration of heavy metals in samples from pyrolysis/melting type is almost six times greater than samples treated under plasma/arc processing. The observations also confirmed that slag from pyrolysis origin contains remarkably higher concentration of metallic inclusions than slag from plasma treatment. In the latter, the metallic compounds are separately tapped from molten slag during the melting treatment that might lead to the generation of safer slag product for end users from environmental viewpoint. PMID:18926624

  5. Performance evaluation for carbonation of steel-making slags in a slurry reactor

    International Nuclear Information System (INIS)

    CO2 sequestration by the aqueous carbonation of steel-making slag under various operational conditions was investigated in this study. The effects of the operational conditions, including type of steel-making slag, reaction time, reaction temperature, and CO2 flow rate, on the performance of the carbonation process were evaluated. The results indicated that the BOF slag had the highest carbonation conversion, approximately 72%, at a reaction time of 1 h, an operating pressure of 101 kPa and a temperature of 60 oC due to its higher BET surface area of BOF slag compared to UF, FA, and BHC slags. The major factors affecting the carbonation conversion are reaction time and temperature. The reaction kinetics of the carbonation conversion can be expressed by the shrinking-core model. The measurements of the carbonated material by the SEM and XRD instruments provide evidence indicating the suitability of using the shrinking-core model in this investigation. Comparison of the results with other studies suggests that aqueous carbonation by slurry reactor is viable due to its higher mass transfer rate.

  6. Performance evaluation for carbonation of steel-making slags in a slurry reactor.

    Science.gov (United States)

    Chang, E-E; Chen, Chung-Hua; Chen, Yi-Hung; Pan, Shu-Yuan; Chiang, Pen-Chi

    2011-02-15

    CO(2) sequestration by the aqueous carbonation of steel-making slag under various operational conditions was investigated in this study. The effects of the operational conditions, including type of steel-making slag, reaction time, reaction temperature, and CO(2) flow rate, on the performance of the carbonation process were evaluated. The results indicated that the BOF slag had the highest carbonation conversion, approximately 72%, at a reaction time of 1h, an operating pressure of 101 kPa and a temperature of 60°C due to its higher BET surface area of BOF slag compared to UF, FA, and BHC slags. The major factors affecting the carbonation conversion are reaction time and temperature. The reaction kinetics of the carbonation conversion can be expressed by the shrinking-core model. The measurements of the carbonated material by the SEM and XRD instruments provide evidence indicating the suitability of using the shrinking-core model in this investigation. Comparison of the results with other studies suggests that aqueous carbonation by slurry reactor is viable due to its higher mass transfer rate. PMID:21168964

  7. Effect of Additives on Melting Point of LATS Refining Ladle Slag

    Institute of Scientific and Technical Information of China (English)

    WANG Hong-ming; LI Gui-rong; DING Zhen-tao; DAI Qi-xun; LI Bo

    2007-01-01

    To avoid slag sticking on the ladle immersion cover during the LATS refining and alloying process, the effect of Al2O3 on the melting point of the ladle slag was studied and the additives including CaF2, B2O3, Li2O, and CaO were used to decrease the melting point of the ladle slag. The melting point was measured using the hemisphere method. The results show that the addition of Al2O3 to the ladle slag increases the melting point. The fluxing action is not remarkable if only CaF2 or CaO is used as the additive. The fluxing action of the composite additive obtained by the mixing of CaO and CaF2 in the mass proportion of wCaO∶wCaF2=2∶1 is preferred. The fluxing action of B2O3 is also notable. When the B2O3 content in mass percent is in the range from 2% to 10%, the corresponding melting point is 1 380 ℃ to 1 290 ℃. The fluxing action of Li2O is the most remarkable. When the Li2O content is up to 5%, the melting point of the slag is lower than 1 300 ℃.

  8. Lignite air-steam gasification in the fluidized bed of iron-containing slag catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, B.N.; Shchipko, M.L.; Golovin, Yu. [Inst. of Chemistry of Natural Organic Materials, Academgorodok, Krasnoyarsk (Russian Federation)

    1995-12-01

    The influence of fluidized bed of iron-containing slag particles on air-steam gasification of powdered Kansk-Achinsk lignite in entrained flow was studied in pilot installation with productivity about 60 kg per hour. Slag of Martin process and boiler slag were used as catalytic active materials until their complete mechanical attrition. Two following methods of catalytic gasification of lignite were compared: the partial gasification in stationary fluidized bed of slag particles with degree of fuel conversion 40-70% and complete gasification in circulating bed of slag particles. In the first case only the most reactive part of fuel is gasified with the simultaneously formation of porous carbon residue with good sorption ability. It was found the catalytic fluidized bed improves heat transfer from combustion to reduction zone of gas-generator and increases the rate of fuel conversion at the temperature range 900-1000{degrees}C. At these temperatures the degree of conversion is depended considerably on the duration time of fuel particles in the catalytic fluidized bed. The influence of catalytic fluidized bed height and velocity of reaction mixture on the temperature profiles in the gas-generator was studied. The optimal relationship was found between the fluidized bed height and velocity of flow which makes possible to produce the gas with higher calorific value at maximum degree of fuel conversion.

  9. Thermoluminescence dating of old copper slags

    International Nuclear Information System (INIS)

    By means of the thermoluminescence method applied to copper slags, copper smelting sites in Turkey, Greece, Jordan, and the Federal Republic of Germany were dated. The samples for thermoluminescence dating were prepared in the same way as for the fine grain method. For the analysis of the radioactive components the following methods were applied: atomic absorption spectrometry, alpha counting, instrumental neutron activation analysis, gamma spectroscopy and fission track mapping. The calculation of the thermoluminescence ages was based on the assumption that the radioactive elements and thermoluminescence phosphorus are uniformly distributed in the slags. (DG)

  10. 活性炭/钢渣吸附-微波氧化法皂化废水处理研究%Study on Activated Carbon/Slag Adsorption-microwave Induced Oxidation Process for Treatment of Saponification Wastewater

    Institute of Scientific and Technical Information of China (English)

    于淑萍; 崔晓雪

    2015-01-01

    以活性炭/钢渣为吸附剂,采用微波诱导氧化法对环氧氯丙烷皂化废水进行降解,考察了活性炭-钢渣用量、 pH值、微波辐射温度、时间、功率等因素对处理效果的影响。结果表明,最佳处理条件为废水:活性炭:钢渣用量固液比为20:1:1,微波辐射功率为850 W,加热温度为100℃,加热时间为25 min, pH值为13。通过正交实验得出pH值对废水处理效果的影响最为显著。在最佳条件下对皂化废水进行连续化处理,去除效果良好。%An effective method of treating saponification wastewater was presented. The technology of microwave radiation with activated carbon and slag adsorbent was used to treat the wastewater. The effective factors such as dosage of activated carbon and slag, pH, and temperature, time and power of microwave radiation were studied. The most optimum treating conditions were as follows: microwave radiation time was 25 min, radiation power was 850 W, pH was 13, wastewater:activated carbon:slag=20:1:1. The pH treatment efficiency was the most obvious based on orthogonal experiments. Its removal efficiency was good under the optimal conditions.

  11. Analysis of the possibility of estimation ecological slag propriety with use the database

    Directory of Open Access Journals (Sweden)

    S. Biernat

    2012-01-01

    Full Text Available This article contains information concerning of the analysis the possibility of defi ning refi nery qualities of the slag based of the thermo-physical and thermodynamical data. The isues presented deals not only with refi ning copper and melting stages, but also of the idea building an optimization program. In its assumption the program is supposed to check and search specifi c data very quickly on the particular types of slag. There are possible and purposeful the construction optimization programme engaging all of the physics chemical infl uence the slag in processes of melting metals alloys. The proposed results, ranges of areas on graphs of phase equilibria’s, demonstrative on the optimum values, will be verifi ed in laboratory conditions and industrial. The initiation the new data the gathered base will be built in system of open base enabling.

  12. Laboratory investigations of stormwater remediation via slag: Effects of metals on phosphorus removal

    Energy Technology Data Exchange (ETDEWEB)

    Okochi, Nnaemeka C. [Environmental Systems Engineering, Faculty of Engineering and Applied Science, University of Regina, Regina, Saskatchewan, S4S 0A2 (Canada); McMartin, Dena W., E-mail: dena.mcmartin@uregina.ca [Environmental Systems Engineering, Faculty of Engineering and Applied Science, University of Regina, Regina, Saskatchewan, S4S 0A2 (Canada)

    2011-03-15

    The use of electric arc furnace (EAF) slag for the removal of phosphorus (P) from various simulated stormwater blends was investigated in the laboratory. The form of P measured was the inorganic orthophosphate (PO{sub 4}-P). The stormwater solutions used in this preliminary study were synthesized as blends of P and typical concentrations of some of the most common and abundant metals in stormwater (e.g. cadmium, copper, lead and zinc), and contacted with EAF slag to determine P removal efficiency and sorptive competition. Results showed that the presence of cadmium, lead and zinc had minimal effect on the removal process; copper was a significant inhibitor of P uptake by the EAF slag media. P removal was greatest in the metal-free and multi-metal stormwater solutions.

  13. Limitation of Sulfide Capacity Concept for Molten Slags

    Science.gov (United States)

    Jung, In-Ho; Moosavi-Khoonsari, Elmira

    2016-04-01

    The sulfide capacity concept has been widely used in pyrometallurgy to define sulfur removal capacities of slags. Typically, the sulfide capacity is considered to be a unique slag property depending only on temperature regardless of partial pressures of oxygen and sulfur. In the present study, it is demonstrated that sulfide capacities of slags in particular those of Na2O-containing slags can vary with partial pressures of oxygen and sulfur due to large solubility of sulfide in Na2O-containing slag systems.

  14. Verification of Steelmaking Slags Iron Content Final Technical Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    J.Y. Hwang

    2006-10-04

    The steel industry in the United States generates about 30 million tons of by-products each year, including 6 million tons of desulfurization and BOF/BOP slag. The recycling of BF (blast furnace) slag has made significant progress in past years with much of the material being utilized as construction aggregate and in cementitious applications. However, the recycling of desulfurization and BOF/BOP slags still faces many technical, economic, and environmental challenges. Previous efforts have focused on in-plant recycling of the by-products, achieving only limited success. As a result, large amounts of by-products of various qualities have been stockpiled at steel mills or disposed into landfills. After more than 50 years of stockpiling and landfilling, available mill site space has diminished and environmental constraints have increased. The prospect of conventionally landfilling of the material is a high cost option, a waste of true national resources, and an eternal material liability issue. The research effort has demonstrated that major inroads have been made in establishing the viability of recycling and reuse of the steelmaking slags. The research identified key components in the slags, developed technologies to separate the iron units and produce marketable products from the separation processes. Three products are generated from the technology developed in this research, including a high grade iron product containing about 90%Fe, a medium grade iron product containing about 60% Fe, and a low grade iron product containing less than 10% Fe. The high grade iron product contains primarily metallic iron and can be marketed as a replacement of pig iron or DRI (Direct Reduced Iron) for steel mills. The medium grade iron product contains both iron oxide and metallic iron and can be utilized as a substitute for the iron ore in the blast furnace. The low grade iron product is rich in calcium, magnesium and iron oxides and silicates. It has a sufficient lime value and

  15. Thermodynamic properties of chromium bearing slags and minerals. A review

    Energy Technology Data Exchange (ETDEWEB)

    Xiao Yanping; Holappa, L.

    1996-12-31

    In this report, the thermodynamic properties of chromium bearing slags and minerals were reviewed based on the available information in the literature. It includes the analysing methods for oxidation state of chromium in slags, oxidation state of chromium and activities of chromium oxides in slags and minerals. The phase diagrams of chromium oxide systems and chromium distributions between slag and metal phases are also covered ill this review. Concerning the analysing methods, it was found that most of the available approaches are limited to iron free slag systems and the sample preparation is very sensitive to the analysing results. In silicate slags under reducing atmosphere, divalent and trivalent chromium co-exist in the slags. It is agreed that the fraction of divalent chromium to total chromium increases with higher temperature, lower slag basicity and oxygen potential. For the slags under oxidising atmosphere, trivalent, pentavalent and hexavalent states were reported to be stable. The activities of CrO and CrO{sub 1.5} were concluded to have positive deviation from ideal solution. Slag basicity has a positive effect and temperature has a negative effect on the activities of chromium oxides. The phase diagrams of the Cr-O, binary, and ternary chromium containing oxide systems have been examined systematically. The analysis shows that the data on the quaternary and quinary systems are insufficient, and require further investigation. The most important features of the chromium containing silicate slags are the large miscibility gaps and the stability of the chromite spinel. (orig.) (76 refs.)

  16. Mechanisms of phosphate removal from aqueous solution by blast furnace slag and steel furnace slag

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    We report the adsorption of phosphate and discuss the mechanisms of phosphate removal from aqueous solution by burst furnace slag (BFS) and steel furnace slag (SFS). The results show that the adsorption of phosphate on the slag was rapid and the majority of adsorption was completed in 5~10 min. The adsorption capacity of phosphate by the slag was reduced dramatically by acid treatment. The relative contribution of adsorption to the total removal of phosphate was 26%~28%. Phosphate adsorption on BFS and SFS follows the Freundlich isotherm, with the related constants ofk 6.372 and 1/n 1.739 for BFS, and ofk 1.705 and 1/n 1.718 for SFS. The pH and Ca2+ concentration were decreased with the addition of phosphate, suggesting the formation of calcium phosphate precipitation. At pH 2.93 and 6.93, phosphate was desorbed by about 36%~43% and 9%~11%, respectively.These results indicate that the P adsorption on the slag is not completely reversible and that the bond between the slag particles and adsorbed phosphate is strong. The X-ray diffraction (XRD) patterns of BFS and SFS before and after phosphate adsorption verify SFS is related to the formation of phosphate calcium precipitation and the adsorption on hydroxylated oxides. The results show that BFS and SFS removed phosphate nearly 100%, indicating they are promising adsorbents for the phosphate removal in wastewater treatment and pollution control.

  17. Study of cryolite preparation from fluoride-containing acid slag in aluminium industry

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A new process of cryolite preparation is studied in this work by selecting a proper system of reaction and weeding impurity technology. The quality of artifial cryolite reaches and exceeds the first level of national standard. The utilization efficient of fluoride-containing acid slag is above 99.5%. It brings considerable economic benefit, and the environment is improved.

  18. Investigation of Bubble-Slag Layer Behaviors with Hybrid Eulerian-Lagrangian Modeling and Large Eddy Simulation

    Science.gov (United States)

    Li, Linmin; Li, Baokuan

    2016-03-01

    In ladle metallurgy, bubble-liquid interaction leads to complex phase structures. Gas bubble behavior, as well as the induced slag layer behavior, plays a significant role in the refining process and the steel quality. In the present work, a mathematical model using the large eddy simulation (LES) is developed to investigate the bubble transport and slag layer behavior in a water model of an argon-stirred ladle. The Eulerian volume of fluid model is adopted to track the liquid steel-slag-air free surfaces while the Lagrangian discrete phase model is used for tracking and handling the dynamics of discrete bubbles. The bubble coalescence is considered using O'Rourke's algorithm to solve the bubble diameter redistribution and bubbles are removed after leaving the air-liquid interface. The turbulent liquid flow that is induced by bubble-liquid interaction is solved by LES. The slag layer fluactuation, slag droplet entrainment and spout eye open-close phenomenon are well revealed. The bubble diameter distribution and the spout eye size are compared with the experiment. The results show that the hybrid Eulerian-Lagrangian-LES model provides a valid modeling framework to predict the unsteady gas bubble-slag layer coupled behaviors.

  19. The Effect of Slag on the Effectiveness of Phosphorus Removal from Ferrous Alloys Containing Carbon, Chromium and Nickel

    Directory of Open Access Journals (Sweden)

    Kawecka-Cebula E.

    2016-03-01

    Full Text Available The aim of this study was to determine the impact of slag composition on phosphorus removal from ferrous solutions containing carbon, chromium and nickel. Additions of cryolite, Na3AlF6, were applied for better fluxing and higher phosphate capacity of the slag. An X-ray analysis of final slags formed during dephosphorization of ferrous solutions containing chromium and nickel with CaO-CaF2 or CaO-CaF2-Na3AlF6 mixtures of different chemical compositions was carried out. The equilibrium composition of the liquid and the solid phase while cooling the slags from 1673K to 298K was computed using FactSage 6.2 software. The performed equilibrium computations indicated that the slags were not entirely liquid at those temperatures. The addition of cryolite causes a substantial increase of the liquid phase of the slag. It also has a favourable effect on the dephosphorization grade of hot metal. The obtained results were statistically processed and presented in the form of regression equations.

  20. Selective Precipitation and Concentrating of Perovskite Crystals from Titanium-Bearing Slag Melt in Supergravity Field

    Science.gov (United States)

    Gao, Jintao; Zhong, Yiwei; Guo, Zhancheng

    2016-08-01

    Selective precipitation and concentrating of perovskite crystals from titanium-bearing slag melt in the supergravity field was investigated in this study. Since perovskite was the first precipitated phase from the slag melt during the cooling process, and a greater precipitation quantity and larger crystal sizes of perovskite were obtained at 1593 K to 1563 K (1320 °C to 1290 °C), concentrating of perovskite crystals from the slag melt was carried out at this temperature range in the supergravity field, at which the perovskite transforms into solid particles while the other minerals remain in the liquid melt. The layered structures appeared significantly in the sample obtained by supergravity treatment, and all the perovskite crystals moved along the supergravity direction and concentrated as the perovskite-rich phase in the bottom area, whereas the molten slag concentrated in the upper area along the opposite direction, in which it was impossible to find any perovskite crystals. With the gravity coefficient of G = 750, the mass fraction of TiO2 in the perovskite-rich phase was up to 34.65 wt pct, whereas that of the slag phase was decreased to 12.23 wt pct, and the recovery ratio of Ti in the perovskite-rich phase was up to 75.28 pct. On this basis, an amplification experimental centrifugal apparatus was exploited and the continuous experiment with larger scale was further carried out, the results confirming that selective precipitation and concentrating of perovskite crystals from the titanium-bearing slag melt by supergravity was a feasible method.

  1. Reduction of nitrobenzene by steel convert slag with Fe(II) system: The role of calcium in steel slag

    International Nuclear Information System (INIS)

    Highlights: ► Steel convert slag (SCS) adsorbed Fe(II) by ion replacement with Ca(II) in SCS. ► Adsorbed Fe(II) on SCS were able to reduce nitrobenzene to aniline. ► A three-step model was proposed for nitrobenzene reduction in SCS-Fe(II) system. - Abstract: Experiments were conducted to examine of nitrobenzene reduction by steel convert slag (SCS) with Fe(II) system. The results showed SCS with Fe(II) was an effective reductant for nitrobenzene at pH 5.5–6.5. Further analysis suggested Fe(II) was adsorbed by SCS through ion replacement with SCS-bound Ca(II). More than 81% of the total Ca(II) in SCS was replaced with dissolved Fe(II), indicating a high adsorption capacity for Fe(II) (more than 5.82 mmol Fe(II)/g SCS). A three step mechanism (replacement process, conversion process and electron transfer process) was proposed for nitrobenzene reduction by SCS with Fe(II) system. The amount of Ca(II) in SCS determined the adsorption capacity for Fe(II) and further determined the reduction capacity of SCS with Fe(II) system.

  2. A Model for Dissolution of Lime in Steelmaking Slags

    Science.gov (United States)

    Sarkar, Rahul; Roy, Ushasi; Ghosh, Dinabandhu

    2016-08-01

    In a previous study by Sarkar et al. (Metall. Mater. Trans. B 46B:961 2015), a dynamic model of the LD steelmaking was developed. The prediction of the previous model (Sarkar et al. in Metall. Mater. Trans. B 46B:961 2015) for the bath (metal) composition matched well with the plant data (Cicutti et al. in Proceedings of 6th International Conference on Molten Slags, Fluxes and Salts, Stockholm City, 2000). However, with respect to the slag composition, the prediction was not satisfactory. The current study aims to improve upon the previous model Sarkar et al. (Metall. Mater. Trans. B 46B:961 2015) by incorporating a lime dissolution submodel into the earlier one. From the industrial point of view, the understanding of the lime dissolution kinetics is important to meet the ever-increasing demand of producing low-P steel at a low basicity. In the current study, three-step kinetics for the lime dissolution is hypothesized on the assumption that a solid layer of 2CaO·SiO2 should form around the unreacted core of the lime. From the available experimental data, it seems improbable that the observed kinetics should be controlled singly by any one kinetic step. Accordingly, a general, mixed control model has been proposed to calculate the dissolution rate of the lime under varying slag compositions and temperatures. First, the rate equation for each of the three rate-controlling steps has been derived, for three different lime geometries. Next, the rate equation for the mixed control kinetics has been derived and solved to find the dissolution rate. The model predictions have been validated by means of the experimental data available in the literature. In addition, the effects of the process conditions on the dissolution rate have been studied, and compared with the experimental results wherever possible. Incorporation of this submodel into the earlier global model (Sarkar et al. in Metall. Mater. Trans. B 46B:961 2015) enables the prediction of the lime dissolution rate

  3. A Model for Dissolution of Lime in Steelmaking Slags

    Science.gov (United States)

    Sarkar, Rahul; Roy, Ushasi; Ghosh, Dinabandhu

    2016-04-01

    In a previous study by Sarkar et al. (Metall. Mater. Trans. B 46B:961 2015), a dynamic model of the LD steelmaking was developed. The prediction of the previous model (Sarkar et al. in Metall. Mater. Trans. B 46B:961 2015) for the bath (metal) composition matched well with the plant data (Cicutti et al. in Proceedings of 6th International Conference on Molten Slags, Fluxes and Salts, Stockholm City, 2000). However, with respect to the slag composition, the prediction was not satisfactory. The current study aims to improve upon the previous model Sarkar et al. (Metall. Mater. Trans. B 46B:961 2015) by incorporating a lime dissolution submodel into the earlier one. From the industrial point of view, the understanding of the lime dissolution kinetics is important to meet the ever-increasing demand of producing low-P steel at a low basicity. In the current study, three-step kinetics for the lime dissolution is hypothesized on the assumption that a solid layer of 2CaO·SiO2 should form around the unreacted core of the lime. From the available experimental data, it seems improbable that the observed kinetics should be controlled singly by any one kinetic step. Accordingly, a general, mixed control model has been proposed to calculate the dissolution rate of the lime under varying slag compositions and temperatures. First, the rate equation for each of the three rate-controlling steps has been derived, for three different lime geometries. Next, the rate equation for the mixed control kinetics has been derived and solved to find the dissolution rate. The model predictions have been validated by means of the experimental data available in the literature. In addition, the effects of the process conditions on the dissolution rate have been studied, and compared with the experimental results wherever possible. Incorporation of this submodel into the earlier global model (Sarkar et al. in Metall. Mater. Trans. B 46B:961 2015) enables the prediction of the lime dissolution rate

  4. Fabrication of low thermal conductivity microporous corundum aggregate by wet process and its slag resist-ance mechanism%低导热微孔刚玉骨料的湿法制备及其抗渣机制研究

    Institute of Scientific and Technical Information of China (English)

    付绿平; 顾华志; 黄奥; 张美杰; 李正坤; 赵义

    2015-01-01

    Microporous corundum aggregate was prepared by wet grinding process and calcining at 1 780 ℃, using α-Al 2 O3 micropowder as the main raw material,as well as alumina sol and starch as binders in order to fabricate lightweight lining refractories with high strength and good slag resistance.The microporous corun-dum aggregate had the bulk density of 3.05 g·cm -3 ,the apparent porosity of 9.1%,the closed porosity of 12.3%,the median pore diameter of 0.43 μm.The thermal conductivity of the microporous corundum was 6.5 W·m -1 ·K -1 at 800 ℃,41.6% lower than that of common corundum.The slag resistance of the microporous corundum aggregate was studied by the immersion method and compared with that of the common corun-dum aggregate to reveal the slag resistant mechanism.Experimental results show that the microporous co-rundum aggregate has obviously better slag resistance than the common corundum aggregate.On the reac-tion interface between microporous corundum and molten slag,a continuous isolation layer,mainly consisting of columnar crystals of CaAl 12 O19 (CA6 )and CaAl 4 O7 (CA2 ),is observed.However,on the reaction interface between common corundum and molten slag,the distribution of columnar crystals is discontinuous,and the aggregate is significantly corroded and penetrated by molten slag.The mechanism is mainly that the micro-porous structure is more advantageous to nucleation and growth of CA2 and CA6 columnar crystals.I n the re-action with the aggregate,the molten slag gets saturated and the critical solution thickness of the micro-porous corundum and the common corundum is 0.16 μm and 0.34 μm,respectively,this is caused by the smaller microporous corundum aggregate pores.The smaller pores also increase the second phase ripening rate of microporous corundum,which is 9.7 times of that of the common corundum.%为了制备轻质高强且耐渣蚀的工作衬耐火材料,首先以α-Al2 O3微粉为主要原料,采用铝溶胶、淀粉为

  5. Investigation of Freeze-Linings in Copper-Containing Slag Systems: Part I. Preliminary Experiments

    Science.gov (United States)

    Fallah-Mehrjardi, Ata; Hayes, Peter C.; Jak, Evgueni

    2013-06-01

    Slag freeze-linings are increasingly used in industrial pyrometallurgical processes to insure that furnace integrity is maintained in aggressive high-temperature environments. Most previous studies of freeze-linings have analyzed the formation of slag deposits based solely on heat-transfer models. The focus of the present research is to determine the impact of slag chemistry and local process conditions on the microstructures, thickness, stability, and heat-transfer characteristics of the frozen deposit at steady-state conditions. The formation of the freeze-linings is studied under controlled laboratory conditions using an air-cooled "cold-finger" technique for Cu-Fe-Si-Al-O slag at equilibrium with metallic copper relevant to the industrial copper smelting processes. The phase assemblages and microstructures of the deposits formed in the cold-finger experiments differ significantly from those expected from phase equilibrium considerations. The freeze-lining deposits have been found, in general, to consist of several layers. Starting from the cold finger, these layers consist of glass; glass with microcrystalline precipitates; closed crystalline layer; and open crystalline layer. Even at steady-state conditions, there was no primary phase sealing layer of delafossite [Cu2O · (Al, Fe)2O3] present at the deposit/liquid interface—these observations differ markedly from those expected from phase equilibrium considerations. The findings have significant practical implications, and potential for the improved design and operation of industrial metallurgical furnaces.

  6. Distribution of Bi Between Slags and Liquid Copper

    Science.gov (United States)

    Chen, Chunlin; Wright, Steven

    2016-06-01

    The distribution of Bi between liquid copper and calcium ferrite slag containing 24 wt pct CaO, iron silicate slag with 25 wt pct SiO2, and calcium iron silicate slags was measured at 1573 K (1300 °C) under controlled CO-CO2 atmosphere. The experimental results showed that bismuth distribution is affected by the oxygen partial pressure, and bismuth is likely to exist in slags in the 2+ oxidation state, i.e., as BiO. The distribution ratio between calcium ferrite slag and metal was found to be close to that of iron silicate slag. The Bi distribution ratio was found to decrease with increasing SiO2 and Al2O3 content in slag. Increasing temperature was found to decrease the Bi distribution ratio between slag and metal. Using the measured equilibrium data on Bi content of the metal and slag and composition dependence of the activity of Bi in liquid copper, the activity and hence activity coefficient of BiO in the slag was calculated. The close value of activity coefficient of BiO in both slags at the same oxygen partial pressure indicates that the CaO-BiO and SiO2-BiO interactions are likely to be at the same level, or the FeO x -BiO interaction is the predominant interaction for BiO in the slag. Therefore at a constant FeO x content in the slag, the CaO-BiO and SiO2-BiO interactions doesn't affect γ_{{BiO}} significantly.

  7. Leaching of heavy metals from steelmaking slags

    Directory of Open Access Journals (Sweden)

    Gomes, J. F. P

    2006-12-01

    Full Text Available Leaching tests with EAF and Ladle slags were performed, using a flow through test and the standard batch test DIN 38414-S4. The previous method was used to simulate the leaching behaviour of steel slags under landfill. The chemical analysis of the leachates during this period shows, in general, for both types of slag, an increase of heavy metal releases with ageing. Standard test method DIN 38414-S4 was used to evaluate leachability of heavy metals by water in unprocessed slags. After more than one year of trials, slag samples submitted to these trials presented very low total leaching levels. The most extracted elements are calcium and magnesium. Nevertheless, in flow-through test, calcium and magnesium leached from solid slags are below 0.5% and all other metals below 0.1%. Leachates obtained with DIN 38414-S4 present, as expected, higher leaching values; however, these are inferior to 5 % (Ca and 1% (other elements.

    Este articulo contiene los resultados obtenidos en ensayos de lixiviación de escorias de acero (horno electrico y cuchara ejecutados siguiendo la metodologia de flujo dinámico así como el ensayo normalizado DIN 38414-S4. El primer ensayo intenta simular el comportamiento de lixiviación de las escorias en vertedero. Para las escorias ensayadas se han complementado los ensayos con el análisis químico de los lixiviados y se ha verificado un aumento de la liberación de metales pesados. El ensayo DIN 38414-S4 se ha utilizado para evaluar la lixiviación por agua de metales pesados, en muestras de escorias originales. Despues de un año de ensayos, se han observado niveles muy bajos de lixiviación. Los elementos mas lixiviados han sido calcio y magnesio. No obstante, en los ensayos de flujo dinámico, el calcio y el magnesio lixiviados de las escorias sólidas era menor de 0,5% y el resto de los otros metales era inferior a 0,1%. Los lixiviados obtenidos con el ensayo DIN 38414-S4 presentan, como era de esperar, valores

  8. Improvement of environmentally relevant qualities of slags from waste-to-energy plants; Verbesserung der umweltrelevanten Qualitaeten von Schlacken aus Abfallverbrennungsanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Alwast, Holger [Prognos AG, Berlin (Germany); Riemann, Axel [RSP GmbH, Herne (Germany)

    2010-10-15

    This expert opinion describes options for improving slag quality (further measures for processing slag, as well as improvements of grate firing in terms of firing-technology), to ensure a slag recovery that is as sustainable as possible. In the context of this project, the term ''slag'' serves as a synonym for solid incineration residues that are generated during the incineration of wastes or of refuse derived fuels and that are separated there (e.g. from the deslagger). The term ''slags'' is also used as a synonym for grate ashes. The main focus of this expertise is on resource and climate protection issues with respect to slag processing. Resource protection refers to the saving of resources and natural raw materials, such as, for example, water and metal ores. Climate protection in this context means CO{sub 2} mitigation through a high specific net energy generation in waste incineration plants, as well as a reduced energy use due to avoided new production of metals, which can be recycled from slag processing. The main measure for improving climate and resource protection in slag processing consists therefore of separating as much metal as possible from slags. By recycling those separated slags, the energy that is needed for the extraction from ores and the raw material ore itself can be saved. This advantage in terms of energy, however, can be partially compensated by the energy use potentially needed for the improvement of slag processing. Further important aspects include the protection of water and soils, as well as the suitability of processed slag for an adequate recovery. These last criteria, however, are not central for this expertise. Currently, 69 municipal solid waste incinerators, hereinafter referred to as Waste-to-Energy (WTE) plants, and 23 refuse derived fuel (RDF) power plants with grate firing are in operation in Germany. Their total capacity amounts to more than 21 million Mg per year. Another 13 RDF

  9. Study on Recovering Copper and Zinc from Slag by Process of Acid Leaching and Solvent Extraction%酸浸-萃取法从炉渣中回收铜、锌的研究

    Institute of Scientific and Technical Information of China (English)

    刘缘缘; 黄自力; 秦庆伟

    2012-01-01

    以硫酸-双氧水浸出低品位炉渣,有效回收了铜和锌.分别进行了pH值、温度、双氧水用量对炉渣中铜锌浸出率的影响研究.研究结果表明:在常压条件下,当pH=2.5,浸出温度70℃,双氧水用量150 L/t时,炉渣中铜和锌的浸出率分别为54.77%和72.33%.用P204作萃取剂,硫酸作反萃剂,得到铜回收率为84.97%,锌回收率为96.47%.%Copper and zinc were effectively recovered by leaching low-grade slag with sulphate-hydrogen peroxide. The effects of pH value, leaching temperature and hydrogen peroxide dosage on leaching rate of copper and zinc were studied. Results showed that leaching rate of copper and zinc from slag reached 54. 77% and 72. 33% , respectively, under normal atmospheric pressure, at a leaching temperature of 70 ℃ , with pH value of 2. 5 and hydrogen peroxide dosage of 150 L/t. The recovery of copper and zinc was 84.97% and 96.47% , respectively, by using P204 as extractant and sulfuric acid as stripping agent.

  10. Stabilization of mercury using waste ladle furnace slag.

    Science.gov (United States)

    Sun, Darren Delai; Zhang, Lilin; Lai, Dickson

    2013-12-01

    Disposal of mercury waste has always provided unique challenges due to its high degree of complexity and volatility. This study evaluated the feasibility of using waste LF slag to form a cementitious matrix capable of providing an effective stabilization/solidification solution for the treatment of mercury wastes. The new matrix was synthesized and simulated through a combination of alkali activation and autoclaving process and doped with mercury nitrate at increasing dosage while monitoring the final form of the mercury and its effects on the mineral stability and structure of the new matrix. Compressive strength of up to 20 N/mm2 was achievable for the original matrix. Promising results were obtained in terms of reduced leachability of the mercury when compared to ordinary Portland cement systems at low doping concentration of around 0.5% by weight. A series of precipitation reactions was found to be the main cause responsible for this successful stabilization, especially the metal sulfide precipitation that occurred with the sulfur present in the original waste LF slag. PMID:24558709

  11. Accelerated carbonation of steel slags in a landfill cover construction

    International Nuclear Information System (INIS)

    Steel slags from high-alloyed tool steel production were used in a full scale cover construction of a municipal solid waste (MSW) landfill. In order to study the long-term stability of the steel slags within the final cover, a laboratory experiment was performed. The effect on the ageing process, due to i.e. carbonation, exerted by five different factors resembling both the material characteristics and the environmental conditions is investigated. Leaching behaviour, acid neutralization capacity and mineralogy (evaluated by means of X-ray diffraction, XRD, and thermogravimetry/differential thermal analysis, TG/DTA) are tested after different periods of ageing under different conditions. Samples aged for 3 and 10 months were evaluated in this paper. Multivariate data analysis was used for data evaluation. The results indicate that among the investigated factors, ageing time and carbon dioxide content of the atmosphere were able to exert the most relevant effect. However, further investigations are required in order to clarify the role of the temperature.

  12. Solidification of spent tributylphosphate by alkali-activated slag

    International Nuclear Information System (INIS)

    The radioactive spent tributylphosphate (TBP) from nuclear industry has large potential hazards, and its processing is a worldwide problem and the study still stays at the level of theory. In this paper, the solidification by alkali-activated slag (AAS) was proposed aimed at the high alkalinity and organic salt content of spent TBP hydrolysate. The effects of activator content, hydrolysate incorporating amount and curing age on the mechanical properties, water resistance, freeze-thaw resistance. hydration degree, alkalinity, mineral composition, and content of active Al and Si were studied. The results indicate that the AAS reveals prominent superiority in the respect of immobilizing spent TBP compared with ordinary Portland cement (OPC) and slag Portland cement (SPC). The compressive strength of immobilization matrix is 18.90 MPa at 28 d incorporating 14.49% spent TBP hydrolysate, while that of OPC is only 8.69 MPa. The leaching resistance, freeze-thaw resistance and shock resistance of AAS are all much better than that of SPC and OPC. (authors)

  13. Hydration of alumina cement containing ferrotitanium slag with polycarboxylate-ethers (PCE) additives

    Science.gov (United States)

    Rechkalov, Denis; Chernogorlov, Sergey; Abyzov, Victor

    2016-01-01

    The paper is discussing results of study of alumina binder containing aluminous cement and ferrotitanium slag from aluminothermic process by Kliuchevskoi Ferroalloys corp. with various additives containing polycarboxylate-ethers (PCE). Selecting ferrotitanium slag as additive is based on the fact that its content of alumina and phase composition is closest to the alumina cement. The composition of the ferrotitanium slag is displayed. In order to compensate the decrease in strength caused by addition of ferrotitanium slag having low activity, PCE additives were added. As PCE additives were used Melflux 1641F, Melflux 2651F and Melflux PP200F by BASF. The effect of additives on the hydration of the binder, depending on the amount and time of additives hardening is shown. The composition of the hydration products in the cement was studied by physico-chemical analysis: derivatography and X-ray analysis. It is found that in the early stages of hardening PCE additives have inhibitory effect on hydration processes and promote new phase amorphization. The optimal content of additives was investigated. The basic properties of the binders have been tested. It was observed that the modified binders meet the requirements of Russian National State Standard GOST 969 to the alumina cement.

  14. Producing fired bricks using coal slag from a gasification plant in indiana

    Science.gov (United States)

    Chen, L.-M.; Chou, I.-Ming; Chou, S.-F.J.; Stucki, J.W.

    2009-01-01

    Integrated gasification combined cycle (IGCC) is a promising power generation technology which increases the efficiency of coal-to-power conversion and enhances carbon dioxide concentration in exhaust emissions for better greenhouse gas capture. Two major byproducts from IGCC plants are bottom slag and sulfur. The sulfur can be processed into commercially viable products, but high value applications need to be developed for the slag material in order to improve economics of the process. The purpose of this study was to evaluate the technical feasibility of incorporating coal slag generated by the Wabash River IGCC plant in Indiana as a raw material for the production of fired bricks. Full-size bricks containing up to 20 wt% of the coal slag were successfully produced at a bench-scale facility. These bricks have color and texture similar to those of regular fired bricks and their water absorption properties met the ASTM specifications for a severe weathering grade. Other engineering properties tests, including compressive strength tests, are in progress.

  15. HCl removal using cycled carbide slag from calcium looping cycles

    International Nuclear Information System (INIS)

    Highlights: • Cycled carbide slag from calcium looping cycles is used to remove HCl. • The optimum temperature for HCl removal of cycled carbide slag is 700 °C. • The presence of CO2 restrains HCl removal of cycled carbide slag. • CO2 capture conditions have important effects on HCl removal of cycled carbide slag. • HCl removal capacity of carbide slag drops with cycle number rising from 1 to 50. - Abstract: The carbide slag is an industrial waste from chlor-alkali plants, which can be used to capture CO2 in the calcium looping cycles, i.e. carbonation/calcination cycles. In this work, the cycled carbide slag from the calcium looping cycles for CO2 capture was proposed to remove HCl in the flue gas from the biomass-fired and RDFs-fired boilers. The effects of chlorination temperature, HCl concentration, particle size, presence of CO2, presence of O2, cycle number and CO2 capture conditions in calcium looping cycles on the HCl removal behavior of the carbide slag experienced carbonation/calcination cycles were investigated in a triple fixed-bed reactor. The chlorination product of the cycled carbide slag from the calcium looping after absorbing HCl is not CaCl2 but CaClOH. The optimum temperature for HCl removal of the cycled carbide slag from the carbonation/calcination cycles is 700 °C. The chlorination conversion of the cycled carbide slag increases with increasing the HCl concentration. The cycled carbide slag with larger particle size exhibits a lower chlorination conversion. The presence of CO2 decreases the chlorination conversions of the cycled carbide slag and the presence of O2 has a trifling impact. The chlorination conversion of the carbide slag experienced 1 carbonation/calcination cycle is higher than that of the uncycled calcined sorbent. As the number of carbonation/calcination cycles increases from 1 to 50, the chlorination conversion of carbide slag drops gradually. The high calcination temperature and high CO2 concentration in the

  16. Improving Beneficiation of Copper and Iron from Copper Slag by Modifying the Molten Copper Slag

    Directory of Open Access Journals (Sweden)

    Zhengqi Guo

    2016-04-01

    Full Text Available In the paper, a new technology was developed to improve the beneficiation of copper and iron components from copper slag, by modifying the molten slag to promote the mineralization of valuable minerals and to induce the growth of mineral grains. Various parameters, including binary basicity, dosage of compound additive, modification temperature, cooling rate and the end point temperature of slow cooling were investigated. Meanwhile, optical microscope, scanning electron microscope and energy dispersive spectrometer (SEM-EDS was employed to determine the mineralogy of the modified and unmodified slag, as well as to reveal the mechanisms of enhancing beneficiation. The results show that under the proper conditions, the copper grade of rougher copper concentrate was increased from 6.43% to 11.04%, iron recovery of magnetic separation was increased significantly from 32.40% to 63.26%, and other evaluation indexes were changed slightly, in comparison with unmodified copper slag. Moreover, matte and magnetite grains in the modified slag aggregated together and grew obviously to the mean size of over 50 μm, resulting in an improvement of beneficiation of copper and iron.

  17. Investigation on the Potentials of Cupola Furnace Slag in Concrete

    Directory of Open Access Journals (Sweden)

    Stephen Adeyemi Alabi

    2013-12-01

    Full Text Available The compressive strength of the concrete designed using blast cupola furnace slag and granulated cupola slag as a coarse aggregate and partial replacement for cement was investigated. A series of experimental studies were conducted involve concrete production in two stages. The first stage comprised of normal aggregate concrete (NAC produced with normal aggregates and 100% ordinary Portland cement (OPC. Meanwhile, the second stage involved production of concrete comprising of cupola furnace slag an aggregates with 100% ordinary Portland cement (OPC and subsequently with 2%, 4%, 6%, 8% and 10% cementitious replacement with granulated cupola furnace slag that had been grounded and milled to less than 75 µm diameter. The outcomes of compressive strength test conducted on the slag aggregate concrete (SAC with and without granulated slag cementitious replacement were satisfactory compared to normal aggregate concretes (NAC.

  18. Aan de slag met niet kerende grondbewerking

    OpenAIRE

    Muijtjens, S.; Swerts, M.; Vervaeke, I.; Meuffels, G.J.H.M.

    2012-01-01

    Glooiende hellingen leveren een prachtig landschap op, maar jammer genoeg gaat dit vaak gepaard met bodemerosie. Zowel voor landbouwers als burgers is erosie ongewenst. Uit verschillende onderzoeken blijkt dat nietkerende grondbewerking en groenbedekking opvallend effectief zijn in de strijd tegen erosie. Toch blijkt het toepassen van niet-kerende grondbewerking niet zo evident. Hoe ga je aan de slag met niet-kerende grondbewerking? Met deze brochure trachten we om jou op weg te helpen naar e...

  19. Electrochemical Method to Accelerate Metal-Slag Reaction

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The electrochemical nature of reaction between melt and slag in a closed system was worked out. Experimental results demonstrated that both the rate and reaction extent increase when the electronic conductor or voltage was applied between melt and slag. The bigger the contact area of the conductor with melts is, the faster the reaction rate is. With the increase of applied voltage which is beneficial for electron's migration between metal and slags, the rate and extent of reaction increase.

  20. Durability of Alkali Activated Blast Furnace Slag

    Science.gov (United States)

    Ellis, K.; Alharbi, N.; Matheu, P. S.; Varela, B.; Hailstone, R.

    2015-11-01

    The alkali activation of blast furnace slag has the potential to reduce the environmental impact of cementitious materials and to be applied in geographic zones where weather is a factor that negatively affects performance of materials based on Ordinary Portland Cement. The scientific literature provides many examples of alkali activated slag with high compressive strengths; however research into the durability and resistance to aggressive environments is still necessary for applications in harsh weather conditions. In this study two design mixes of blast furnace slag with mine tailings were activated with a potassium based solution. The design mixes were characterized by scanning electron microscopy, BET analysis and compressive strength testing. Freeze-thaw testing up to 100 freeze-thaw cycles was performed in 10% road salt solution. Our findings included compressive strength of up to 100 MPa after 28 days of curing and 120 MPa after freeze-thaw testing. The relationship between pore size, compressive strength, and compressive strength after freeze-thaw was explored.

  1. Flexural Fatigue performance of Alkali Activated Slag Concrete mixes incorporating Copper Slag as Fine Aggregate

    Directory of Open Access Journals (Sweden)

    Mithun B.M.

    2015-06-01

    Full Text Available The present investigation attempts a detailed study of mechanical properties and fatigue characteristics of a new class of Alkali Activated Slag Concrete (AASC mixes incorporating Copper Slag (CS as fine aggregates. The natural river sand is replaced with Copper Slag, upto 100% (by volume as fine aggregate in these AASC mixes. The behavior of plain concrete prisms, cast with this range of AASC mixes under dynamic cyclic loads with sand/CS fine aggregates is studied and is compared with conventional OPC-based concrete specimens. The results indicate that incorporation of CS even upto 100% as fine aggregates, did not have any adverse effects on the mechanical properties of AASC mixes. The AASC mixes with CS displayed slightly better fatigue performance as compared to AASC mix with river sand. An attempt is also made herein to statistically describe the fatigue life data of AASC mixes using a 2-parameter Weibull distribution.

  2. Steel Slag Filters to Upgrade Phosphorus Removal in Constructed Wetlands: Two Years of Field Experiments

    OpenAIRE

    Barca, C.; Troesch, S.; Meyer, D.; Drissen, P.; Andres, Y; Chazarenc, F.

    2013-01-01

    Electric arc furnace steel slag (EAF-slag) and basic oxygen furnace steel slag (BOF-slag) were used as filter substrates in two horizontal subsurface flow filters (6 m3 each) designed to remove phosphorus (P) from the effluent of a constructed wetland. The influences of slag composition, void hydraulic retention time (HRTv), temperature, and wastewater quality on treatment performances were studied. Over a period of almost two years of operation, the filter filled with EAF-slag removed 37%...

  3. Development and optimisation of process parameters for recovery of uranium from calcia slag and lining material (SLM) by leaching process and subsequent recovery of uranium from the leach liquor generated

    International Nuclear Information System (INIS)

    Presently uranium value is recovered by nitric acid dissolution of the SLM, to get uranyl nitrate solution (UNS) and subsequent solvent extraction process. UNS generated After SLM dissolution is very lean in uranium content and create difficulty in solvent extraction. Moreover, NOX is also generated during SLM dissolution in nitric acid. An alternate process was developed where nitric acid is not being used and uranium is being recovered by leaching out the SLM using acetic acid. The process was also optimised for recovery and overall economics of the process by using process effluent AALL (Acetic Acid Leach Liquor) as a leaching agent. The uranium value in the leach liquor was precipitated by using sodium hydroxide. The precipitate was dissolved in nitric acid and the Uranyl Nitrate Solution generated was having Uranium concentration of 15-30 g/l. The alternate process developed will have less effluent generation, less NOX generation and will produce more concentrated UNS in comparison to the nitric acid dissolution process

  4. Artificial neural network model to predict slag viscosity over a broad range of temperatures and slag compositions

    Energy Technology Data Exchange (ETDEWEB)

    Duchesne, Marc A. [Chemical and Biological Engineering Department, University of Ottawa, 161 Louis Pasteur, Ottawa, Ont. (Canada); CanmetENERGY, 1 Haanel Drive, Ottawa, Ontario (Canada); Macchi, Arturo [Chemical and Biological Engineering Department, University of Ottawa, 161 Louis Pasteur, Ottawa, Ont. (Canada); Lu, Dennis Y.; Hughes, Robin W.; McCalden, David; Anthony, Edward J. [CanmetENERGY, 1 Haanel Drive, Ottawa, Ontario (Canada)

    2010-08-15

    Threshold slag viscosity heuristics are often used for the initial assessment of coal gasification projects. Slag viscosity predictions are also required for advanced combustion and gasification models. Due to unsatisfactory performance of theoretical equations, an artificial neural network model was developed to predict slag viscosity over a broad range of temperatures and slag compositions. This model outperforms other slag viscosity models, resulting in an average error factor of 5.05 which is lower than the best obtained with other available models. Genesee coal ash viscosity predictions were made to investigate the effect of adding Canadian limestone and dolomite. The results indicate that magnesium in the fluxing agent provides a greater viscosity reduction than calcium for the threshold slag tapping temperature range. (author)

  5. Assessment of hexavalent chromium release in Malaysian electric arc furnace steel slag for fertilizer usage

    Science.gov (United States)

    Bankole, L. K.; Rezan, S. A.; Sharif, N. M.

    2014-03-01

    This study investigates the leaching of hexavalent chromium (Cr (VI)) from electric arc furnace steel slag as Cr (VI) is classified as human carcinogen. Batch leaching tests were performed for 16 days. The lixiviants used were alkaline, de-ionized and rain water. After 16 days, Cr (VI) was found to be highest in alkaline water (0.03 mg/L) and lowest in de-ionized water (0.01 mg/L). Besides the lixiviants used, slag stirring speed and liquid to solid ratio also affect Cr (VI) released. The experimental work was complimented with slag characterization using XRF, XRD and SEM/EDX analysis. The leaching process was also simulated via Factsage software to calculate isothermal pourbaix diagrams. The Cr (VI) released was low and below the threshold of 0.1 mg/L set for public water systems. Recycle the slag as fertilizer should be considered safe as it does not exceed the safety limit set for Cr (VI) dissolution.

  6. Effects of thin-film accelerated carbonation on steel slag leaching.

    Science.gov (United States)

    Baciocchi, R; Costa, G; Polettini, A; Pomi, R

    2015-04-01

    This paper discusses the effects of accelerated carbonation on the leaching behaviour of two types of stainless steel slags (electric arc furnace and argon oxygen decarburisation slag). The release of major elements and toxic metals both at the natural pH and at varying pH conditions was addressed. Geochemical modelling of the eluates was used to theoretically describe leaching and derive information about mineralogical changes induced by carbonation. Among the investigated elements, Ca and Si were most appreciably affected by carbonation. A very clear effect of carbonation on leaching was observed for silicate phases; geochemical modelling indicated that the Ca/Si ratio of Ca-controlling minerals shifted from ∼ 1 for the untreated slag to 0.5-0.67 for the carbonated samples, thus showing that the carbonation process left some residual Ca-depleted silicate phases while the extracted Ca precipitated in the form of carbonate minerals. For toxic metals the changes in leaching induced by carbonation appeared to be mainly related to the resulting pH changes, which were as high as ∼ 2 orders of magnitude upon carbonation. Depending on the specific shape of the respective solubility curves, the extent of leaching of toxic metals from the slag was differently affected by carbonation. PMID:25596552

  7. Recovery of Copper from the Slag of Khatoonabad Flash Smelting Furnace by Flotation Method

    Science.gov (United States)

    Karimi, Nader; Vaghar, Ramez; Mohammadi, Mohammad Reza Tavakoli; Hashemi, Seyed Ahmad

    2013-04-01

    Copper loss in the slag of Khatoonabad flash smelting furnace is estimated to be about 1-3 %. At present, the electric slag cleaning furnace is used for the recovery of copper from slag. However, due to low recovery efficiency of electric furnace along with high consumption of electrical energy and water, selection of a method to enable minimum energy consumption and maximum recovery of copper seems to be essential. Therefore, the aim of this study was to investigate the possibility of copper recovery from this slag using flotation method, and to determine the effective parameters involved in the process. Based on the experiments conducted, the best results were obtained for pH 11.5, 60 g/t Z11 and R407 collectors with a weighing ratio of 3-2, 40 g/t of MIBC and A65 frothers with an equal weighting ratio and grinding time of 45 min. Under these conditions, the copper concentrate grade and recovery were 19 and 91.1 % in the rougher step, 27.4 and 96.3 % in the cleaner step, and 32 and 93 % in the recleaner step, respectively.

  8. Assessment of hexavalent chromium release in Malaysian electric arc furnace steel slag for fertilizer usage

    International Nuclear Information System (INIS)

    This study investigates the leaching of hexavalent chromium (Cr (VI)) from electric arc furnace steel slag as Cr (VI) is classified as human carcinogen. Batch leaching tests were performed for 16 days. The lixiviants used were alkaline, de-ionized and rain water. After 16 days, Cr (VI) was found to be highest in alkaline water (0.03 mg/L) and lowest in de-ionized water (0.01 mg/L). Besides the lixiviants used, slag stirring speed and liquid to solid ratio also affect Cr (VI) released. The experimental work was complimented with slag characterization using XRF, XRD and SEM/EDX analysis. The leaching process was also simulated via Factsage software to calculate isothermal pourbaix diagrams. The Cr (VI) released was low and below the threshold of 0.1 mg/L set for public water systems. Recycle the slag as fertilizer should be considered safe as it does not exceed the safety limit set for Cr (VI) dissolution

  9. Phase Equilibria of ``Cu2O''-``FeO''-CaO-MgO-Al2O3 Slags at PO2 of 10-8.5 atm in Equilibrium with Metallic Copper for a Copper Slag Cleaning Production

    Science.gov (United States)

    Henao, Hector M.; Pizarro, Claudio; Font, Jonkion; Moyano, Alex; Hayes, Peter C.; Jak, Evgueni

    2010-12-01

    Limited data are available on phase equilibria of the multicomponent slag system at the oxygen partial pressures used in the copper smelting, converting, and slag-cleaning processes. Recently, experimental procedures have been developed and have been applied successfully to characterize several complex industrial slags. The experimental procedures involve high-temperature equilibration on a substrate and quenching followed by electron probe X-ray microanalysis. This technique has been used to construct the liquidus for the “Cu2O”-“FeO”-SiO2-based slags with 2 wt pct of CaO, 0.5 wt pct of MgO, and 4.0 wt pct of Al2O3 at controlled oxygen partial pressures in equilibrium with metallic copper. The selected ranges of compositions and temperatures are directly relevant to the copper slag-cleaning processes. The new experimental equilibrium results are presented in the form of ternary sections and as a liquidus temperature vs Fe/SiO2 weight ratio diagram. The experimental results are compared with the FactSage thermodynamic model calculations.

  10. Stabilization of residues obtained from the treatment of laboratory waste: Part 2--transformation of plasma vitrified slag into composites.

    Science.gov (United States)

    Kuo, Yi-Ming; Tseng, Ho-Jung; Chang, Juu-En; Chao, Chih-C; Wang, Chih-Ta; Chang-Chien, Guo-Ping; Wang, Jian-Wen

    2011-01-01

    The Sustainable Environment Research Center of National Cheng Kung University in Taiwan has set up a treatment plant to dispose of laboratory waste. In the treatment process, the residue from the incineration system and the physical and chemical system is vitrified by a plasma melting system. Part 1 of this study described the treatment path of metals during vitrification. In Part 2, plasma vitrified slag is reused by using a molding technology. Unsaturated polyester resin and glass fiber were used as the molding material and additive, respectively, in the molding process. With an appropriate mixing ratio of unsaturated polyester resin, glass fiber, and slag, the physical properties of composites improved, and the ultimate tensile strength reached 17.6 MPa. However, an excess amount of slag reduced the strength and even retarded the production of composites. Differential thermal analysis and the water bathing test results show that the composite decomposed at 80 degrees C and that it vaporized at 187 degrees C. Although the unsaturated polyester resin decomposed, the metal encapsulated in the slag did not leach out. The results show that the reuse of slag using molding technology should be taken into consideration. PMID:21305891

  11. Penetration and dissolution of refractory of magnetite - chrome by fayalite slag

    International Nuclear Information System (INIS)

    Magnesium-chrome refractory have been used with success at high temperatures in different metallurgist processes, such as iron and steel, cement industry and non ferrous pyro metallurgist processes. In particular in the smelting, in the processes of reforming of raffinate of copper. Those materials have good characteristics in relation with the use and the requirements of heat shock resistance. However, they represent an important problem for the environment. The aim of this research was to investigate the interactions between the slag generated in the converter Peirce-Smith in copper and Magnesium-chrome refractory bricks. The infiltration events and chemical attacks in the refractory material caused by the slag formed during the copper conversion process have been studied by means of the development of the different laboratory tests at temperatures of until 1300 celsius degrade.

  12. Foamability of stainless steelmaking slags in an EAF

    Science.gov (United States)

    Kerr, James John

    Foaming in electric furnace steelmaking is desirable to allow for a longer arc and subsequently higher power operation in order to reduce the tap to tap time and consequently increase productivity. Stainless steelmaking slags do not foam as well as carbon steelmaking slags. To produce foam, the foamability or foam index of a slag and the gas generation rate must be adequate. The possible causes for the poor foamability of stainless steelmaking slags were examined in this research. Specifically the foam index of a simulated stainless steelmaking slag containing chrome oxide was measured and the rate at which carbon reacts with Cr2O3, CrO, and FeO was also measured. The experimental results show that the foam index of stainless steelmaking slags is comparable to carbon steelmaking slags provided that the amount of solid chrome oxide particles or complexes is not excessive. This indicates the low foamability is not due to a poor foam index. Gas is normally generated by cycling carbon into the slag, which produces CO by reducing oxides in the slag. The experimental results demonstrate that the reaction rate of carbon with CrO dissolved in the slag and hence the generation of CO is significantly slower than for the reaction rate of carbon with FeO dissolved in slags. Therefore, the lack of FeO or other reducible oxides in stainless steelmaking slags is a primary reason for the poor foamability. Experimental results indicate that limestone, nickel oxide, calcium nitrate, and waste oxide briquettes generate gas at sufficient rates to induce foaming when added to the stainless steelmaking slag. Heat transfer most likely controls the rate of CO2 generated by limestone and NiO reduction is controlled by mass transfer of NiO to the carbon in the slag. WOBs generate gas very rapidly due to intimate mixing of the carbon and iron oxides at unit activity. Calcium nitrate generates gas by dissociation and heat transfer likely controls the dissociation rate. Simple models are

  13. Steel mill slags energy potential: the case of the steel factory of Arcelor-Mittal in Asturias (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez Alvarez, Eduardo; Trashorras, Antonio J.G.; Xiberta Bernat, Jorge [University of Oviedo, Energy Department, Oviedo, Asturias (Spain); Suarez Cuesta, Jose Manuel [Arcelor-Mittal Asturias, Aviles, Asturias (Spain)

    2012-10-15

    Slag accounts for most of the residuals or by-products of the steel manufacturing process and represents a not inconsiderable amount of energy waste and CO{sub 2} emissions. Energy recovery from steel mill slags is not actually performed because of the difficulty of the industrial implementation, but the actual demand and the incentives for new electricity generation plants based on renewable energies and on industrial waste heat recovery offer a new opportunity to evaluate the feasibility of this process. This article presents a review of the slag energy potential on a global scale, and a proposal for a recovery plant in the factories of Arcelor-Mittal in Asturias (Spain), based on a steam Rankine cycle for electricity production in a turbine. The plant production and viability have been analyzed using the typical technical and economic values for this kind of plant. Also, a parametric study has been performed on the heat recuperator efficiency and investment rate. (orig.)

  14. Towards zero-waste mineral carbon sequestration via two-way valorization of ironmaking slag

    OpenAIRE

    Chiang, Yi Wai; Santos, Rafael; Elsen, Jan; Meesschaert, Boudewijn; Martens, Johan; Van Gerven, Tom

    2014-01-01

    A three-stage process was developed to transform blast furnace slag (BFS) into two valuable products: precipitated calcium carbonate (PCC) and zeolitic materials. The conceptualized process aims to simultaneously achieve sustainable CO2 sequestration and solid waste elimination. Calcium is first selectively extracted by leaching with an organic acid, followed by carbonation of the leachate to precipitate CaCO3. In parallel, the hydrothermal conversion of the extracted solid residues in alkali...

  15. Mechanical Properties and Eco-Efficiency of Steel Fiber Reinforced Alkali-Activated Slag Concrete

    OpenAIRE

    Sun-Woo Kim; Seok-Joon Jang; Dae-Hyun Kang; Kyung-Lim Ahn; Hyun-Do Yun

    2015-01-01

    Conventional concrete production that uses ordinary Portland cement (OPC) as a binder seems unsustainable due to its high energy consumption, natural resource exhaustion and huge carbon dioxide (CO2) emissions. To transform the conventional process of concrete production to a more sustainable process, the replacement of high energy-consumptive PC with new binders such as fly ash and alkali-activated slag (AAS) from available industrial by-products has been recognized as an alternative. This p...

  16. Design of Inorganic Polymer Mortar from Ferricalsialic and Calsialic Slags for Indoor Humidity Control

    Directory of Open Access Journals (Sweden)

    Elie Kamseu

    2016-05-01

    Full Text Available Amorphous silica and alumina of metakaolin are used to adjust the bulk composition of black (BSS and white (WSS steel slag to prepare alkali-activated (AAS mortars consolidated at room temperature. The mix-design also includes also the addition of semi-crystalline matrix of river sand to the metakaolin/steel powders. The results showed that high strength of the steel slag/metakaolin mortars can be achieved with the geopolymerization process which was particularly affected by the metallic iron present into the steel slag. The corrosion of the Fe particles was found to be responsible for porosity in the range between 0.1 and 10 µm. This class of porosity dominated (~31 vol % the pore network of B compared to W samples (~16 vol %. However, W series remained with the higher cumulative pore volume (0.18 mL/g compared to B series, with 0.12 mL/g. The maximum flexural strength was 6.89 and 8.51 MPa for the W and B series, respectively. The fracture surface ESEM observations of AAS showed large grains covered with the matrix assuming the good adhesion bonds between the gel-like geopolymer structure mixed with alkali activated steel slag and the residual unreacted portion. The correlation between the metallic iron/Fe oxides content, the pore network development, the strength and microstructure suggested the steel slag's significant action into the strengthening mechanism of consolidated products. These products also showed an interesting adsorption/desorption behavior that suggested their use as coating material to maintain the stability of the indoor relative humidity.

  17. Investigation of Copper Ammonia Leaching from Smelter Slags: Characterization, Leaching and Kinetics

    Science.gov (United States)

    Bidari, Ehsan; Aghazadeh, Valeh

    2015-10-01

    Although ammonia leaching of copper from slags has been reported generally as a part of copper slag utilization methods, but no detailed studies have been reported in the literature. In this research, we tried to investigate the effect of different parameters on ammonia leaching of copper from copper smelting slag by identifying different copper-bearing phases and following them during leaching time. Mineralogical characterization of the smelting slag (1.7 pct Cu) was done using X-ray fluorescence, X-ray diffraction, optical microscopy, diagnostic leaching tests, and scanning electron microscopy. The characterization studies indicated that main copper-bearing species are soluble copper oxides and chalcocite along with minor amount of covellite, bornite, blister copper particles, and chalcopyrite. It was also found that only approximately 0.2 pct Cu was present in the insoluble bulk silicate phases. These results suggest that approximately 88 pct of the total copper of slag could be extracted by ammonia sulfide leaching. Leaching tests were carried out and the effects of various parameters, namely pH, ammonia concentration, temperature, presence of oxygen, stirring speed, and pulp density were examined on copper leaching. The temperature and stirring speed had the most pronounced effect on the copper leaching, whereas ammonia affected the leaching yield at low concentrations of ammonia. It was found that 78 pct of Cu could be extracted within 4 hours and under optimum conditions: T = 343 K (70 °C), 2M ammonia, pH 10.5, stirring speed = 900 rpm, pulp density = 10 pct ( w s/ v). The kinetic data were analyzed with the shrinking core models, and it was found that the leaching process is controlled by both the interfacial transfer and diffusion across the product layer and the activation energy is calculated to be 49.4 kJ mol-1.

  18. Measurement of Moisture Content in Sand, Slag, and Crucible Materials

    International Nuclear Information System (INIS)

    The deinventory process at Rocky Flats (RFETS) has included moisture content measurements of sand, slag, and crucible (SSC) materials by performing weight loss measurements at 210 degrees - 220 degrees Celsius on representative samples prior to packaging for shipment. Shipping requirements include knowledge of the moisture content. Work at the Savannah River Technology Center (SRTC) showed that the measurement at 210 degrees - 220 degrees Celsius did not account for all of the moisture. The objective of the work in this report was to determine if the measurement at 210 degrees - 220 degrees Celsius at RFETS could be used to set upper bounds on moisture content and therefore, eliminate the need for RFETS to unpack, reanalyze and repack the material

  19. A new methodology using mathematical treatment in uranium recovery of slags from U-metal production

    International Nuclear Information System (INIS)

    U3 Si2 fuel was developed by the Fuel Cycle Department of IPEN/CNEN - SP in order to provide high density fuel elements for the IEA-R1m swimming pool reactor. Uranium containing magnesium fluoride slags are produced during the reduction of U F4 to metallic uranium, the first step of U3 Si2 production. Since enriched uranium is used and taking in account process economics and environmental impacts, the recovery of uranium from the slags is highly recommended. This work deals with the uranium recovery from magnesium fluoride slag via nitric acid leaching process using a new methodology for the study. A statistical procedure for process optimization was applied using a fractional factorial design at two levels and four variables represented as 24-1. Variance analysis followed by multiple regression was used, setting up a first order polygonal model, as follow: y 92,409 +3,825 x1 - 0,875 x3 + 1,65 x4 - 0,95 x3 x4 Standard error 1,04572. This equation represents the variables and the most suitable interactions in the uranium recovery process. By using this equation, one can obtain in advance and without making experiments the values from the process variables for a giving process yield. (author)

  20. Analysis of slag material in the production of zinc oxide

    Czech Academy of Sciences Publication Activity Database

    Luptáková, Natália; Pešlová, F.

    Brno : University of Defence, 2014 - (Stodola, J.; Šťastný, J.; Vališ, D.; Neumann, V.), s. 237-242 ISBN 978-80-7231-969-5. [Deterioration, Dependability, Diagnostics. Brno (CZ), 07.10.2014-08.10.2014] Institutional support: RVO:68081723 Keywords : zinc slag * production of zinc oxide * analysis of slag * phases Subject RIV: JG - Metallurgy

  1. A ceramographic evaluation of chromia refractories corroded by slag

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, Alton H.; Chinn, Richard E.

    2001-01-01

    This paper describes the ceramographic preparation of Cr{sub 2}O{sub 3}-Al{sub 2}O{sub 3} refractory bricks and subsequent microstructural analysis to determine the corrosive effects of molten slag. The porous and friable nature of the brick, especially after exposure to the slag or its individual components, presented some problems in the preparation.

  2. Interactions of Refractory Materials with Molten Gasifier Slags

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, Jimichiro; Sridhar, Seetharaman; Kwong, Kye-Sing; Bennett, James; Moss, Tyler

    2011-04-01

    The current study focuses on the analysis of sessile-drop interfacial reactions between two synthetic slags (based on average ash chemistries of coal and petcoke feedstock) and two refractory materials (90 wt% Cr{sub 2}O{sub 3}–10 wt% Al{sub 2}O{sub 3} and 100 wt% Al{sub 2}O{sub 3}), using a Confocal Scanning Laser Microscope (CSLM). Ground slag samples (less than 325 mesh) were placed at specific microstructure locations on refractory substrates and heated to 1500 °C in an atmosphere of CO/CO{sub 2} gas mixture (volume ratio = 1.8), using a gold-image heating chamber. Cross-sections of the slag/refractory interface indicated unique slag penetration into preferred areas of the refractory and grain dissolution into the slag which promoted spalling of the refractory. Initially, the slag attacked both grain boundaries and fine microstructure areas, freeing alumina grains into the slag. The formation of VO{sub x}-based crystalline material in the petcoke slag was found to alter the liquid composition. Chemical spalling of Cr-containing crystal layer also facilitated degradation of the refractory.

  3. Interactions of refractory materials with molten gasifier slags

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, J.; Sridhar, S.; Bennett, J.; Kwong, K.S.; Moss, T. [US DOE, Albany, OR (United States)

    2011-04-15

    The current study focuses on the analysis of sessile-drop interfacial reactions between two synthetic slags (based on average ash chemistries of coal and petcoke feedstock) and two refractory materials (90 wt% Cr2O{sub 3}-10 wt% Al{sub 2}O{sub 3} and 100 wt% Al{sub 2}O{sub 3}), using a Confocal Scanning Laser Microscope (CSLM). Ground slag samples (less than 325 mesh) were placed at specific microstructure locations on refractory substrates and heated to 1500 {sup o}C in an atmosphere of CO/CO{sub 2} gas mixture (volume ratio = 1.8), using a gold-image heating chamber. Cross-sections of the slag/refractory interface indicated unique slag penetration into preferred areas of the refractory and grain dissolution into the slag which promoted spalling of the refractory. Initially, the slag attacked both grain boundaries and fine microstructure areas, freeing alumina grains into the slag. The formation of VOx-based crystalline material in the petcoke slag was found to alter the liquid composition. Chemical spalling of Cr-containing crystal layer also facilitated degradation of the refractory.

  4. Analysis of the Rheological Behaviour of Selected Semi-Solid Slag Systems in Blast Furnace Flow Conditions

    Directory of Open Access Journals (Sweden)

    Migas P.

    2015-04-01

    Full Text Available The rheological properties of liquid and semi-solid systems of slag and hot metal in a blast furnace are extremely important from the perspective of their dripping in the unit. The rheological nature and the values of the dynamic viscosity coefficient of liquid and semi-solid phases - slag and hot metal - determine the permeability of the zones in which those systems exist. The modelling of dripping processes and e.g. static and dynamic holding/retention of liquid in the bed, requires an accurate description of the rheological behaviour of slag and iron systems. Determining the liquid flow through the lump bed of the blast furnace is based on the assumption that liquids in the unit in the whole range of their occurrence are similar to a Newtonian ideal liquid. This study presents an analysis of the findings of high-temperature rheometric measurements of CaO-SiO2-Al2O3-MgO systems, liquid, semi-solid slags of the blast furnace type doped with TiO2 and solids in the form of TiN. The tests were performed within a temperature range of 1310-1490°C. Also measurement results for glycerol solutions with concentrations of 86% and 100% at the ambient temperature, simulating blast furnace slags with various contents of solids - PC, anthracite - are presented.

  5. Roles of Mineralogical Phases in Aqueous Carbonation of Steelmaking Slag

    Directory of Open Access Journals (Sweden)

    Huining Zhang

    2016-05-01

    Full Text Available Mineralogical phases of steelmaking slags have significant influences on the carbonation of the slags. In this paper, the effects of temperature and reaction time on the conversion of calcium-related phases and the carbonation degree of a slag sample were studied. The experimental conditions were a liquid-to-solid ratio of 20 mL/g, a carbon dioxide flow rate of 1 L/min and a slag particle size of 38–75 μm. The results show that the optimum carbonation temperature and reaction time are 60 °C and 90 min, respectively, and calcite phase content is about 26.78% while the conversion rates of Ca3Al2O6, CaSiO3, Ca2SiO4 and free CaO are about 40%, 42.46%, 51% and 100%, respectively, and the carbon dioxide sequestration efficiency is about 170 g/kg slag.

  6. Chemical and mineralogical characterizations of a copper converter slag

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A copper converter slag was examined chemically and mineralogically to determine its existing phases, in particular those containing Co and Cu. The slag consists predominantly of fayalite and magnetite, together with some glass,chalcocite, and metallic copper. Copper is entrapped in the slag mostly as chalcocite and metallic copper, as well as trace copper oxide. There was no indication of any independent Co mineral in the slag, but Co was found to be enriched in fayalite and megnetite as solid solution, although Co was detected in all the phases of the slag by SEM-EDX (scanning electron microscopy equipped with model EDAX-9100 energy dispersive spectrometer) and WDS (model WDX-2A X-ray wave-length dispersive spectrometer).

  7. Slag-Resistance of MgAlON Spinel

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The slag-resistance and microstructural changes after the slag tests of MgAlON spinel containing different amount of nitrogen were studied by means of crucible slag-resistant experiment, SEM and EDS in the work. The results show that the slag-resistance of MgAlON is dependent on the nitrogen content, and the optimum amount is 2.88%. The structure is not changed although the grains have been permeated by some silicon, calcium and iron. A glass phase which contained nitrogen formed in the metamorphic layer. The glass can improve the ability of the slag-resistance of MgAlON because of its higher viscosity.

  8. Solidification of stainless steel slag by accelerated carbonation.

    Science.gov (United States)

    Johnson, D C; MacLeod, C L; Carey, P J; Hills, C D

    2003-06-01

    On exposure to carbon dioxide (CO2) at a pressure of 3 bars, compacts formed from pressed ground slag, and 12.5 weight percent water, were found to react with approximately 18% of their own weight of CO2. The reaction product formed was calcium carbonate causing the slag to self-cement. Unconfined compressive strengths of 9MPa were recorded in carbonated compacts whereas strengths of < 1 MPa were recorded in non-carbonated slag compacts. As molten stainless steel slag containing dicalcium silicate (C2S) cools it can undergo several phase transitions. The final transformation from the beta-polymorph to gamma-C2S is accompanied by a volume change that causes the slag to self-pulverise or 'dust'. As a consequence of this the fine grained portion of the slag contains more of this phase whilst the coarser particles of the slag contain more of the calcium magnesium silicates that contribute the bulk of the waste. The fine fraction (< 125 microm) of the slag when ground is found to react to the same extent as the ground bulk slag and produces compacts with equivalent strength. A coarser fraction (4-8 mm) when ground to a similar grading does not react as extensively and produces a weaker product. Additions of ordinary Portland cement (OPC) at 5 and 10 percent by weight did not alter the degree of reaction during carbonation of the bulk slag or ground fine fraction, however the strength of the 4-8 mm fraction was increased by this change. PMID:12868521

  9. Evaluation of slag regime in ladle during utilization of briquetted synthetic slag in VHM a.s.

    Directory of Open Access Journals (Sweden)

    L. Socha

    2012-10-01

    Full Text Available Purpose: The paper focuses on evaluation of slag regime by the help of synthetic slags based on Al2O3. The comparion of influence of synthetic slags on the production of two chosen grades of steels focused on evaluation of effectivity of created refining slag during treatment in the secondary metallurgy was the objective of plant experiments.Design/methodology/approach: During evaluation of slag regime in the ladle, steel samples for assessment of desulphurization degree were taken under the plant conditions. Slag samples were also taken for evaluation of chosen parameters: basicity, content of easily reducible oxides, proportion of CaO/Al2O3and Mannesmann’s index. The temperature and oxygen activity in steel was continuously measured too.Findings: From plant experiments, it was found out that during using of two different types of synthetic slags during production of steel grades St52-3 and S34MnV similar values of desulphurization degree were achieved. Chosen parameters of ladle slag were monitored and it was demonstrated that the developed synthetic slag B reaches the results comparable with the standard used synthetic slag A.Research limitations/implications: Plant experiments were made under conditions of VÍTKOVICE HEAVY MACHINERY a.s. plant Obtained results are limited by the testing during production of two different steel grades St52-3, S34MnV and by the specific technology of production formed by EAF→LF→VD/VCD.Practical implications: The research results made it possible to realize the optimalization of slag regime under the plant conditions of VÍTKOVICE HEAVY MACHINERY a.s. plant. It was proved that developed synthetic slag B from the company JAP TRADING s.r.o. can adequately replace the common synthetic slag A.Originality/value: Results mentioned in this paper are intended for steel producers and they represent basic information about possibilities of slag regime optimalization in the ladle.

  10. Preparation of novel ceramics with high CaO content from steel slag

    International Nuclear Information System (INIS)

    Highlights: • Efficiently utilize such solid waste with high CaO content. • A novel ceramics was put forward by traditional ceramic process. • The novel ceramics attained high strength. • Sintering mechanisms of the novel ceramics were discussed. - Abstract: Steel slag, an industrial waste discharged from steelmaking process, cannot be extensively used in traditional aluminosilicate based ceramics manufacturing for its high content of calcium oxide. In order to efficiently utilize such solid waste, a method of preparing ceramics with high CaO content was put forward. In this paper, steel slag in combination with quartz, talcum, clay and feldspar was converted to a novel ceramic by traditional ceramic process. The sintering mechanism, microstructure and performances were studied by scanning electron microscope (SEM), X-ray diffraction (XRD) techniques, combined experimenting of linear shrinkage, water absorption and flexural strength. The results revealed that all crystal phases in the novel ceramic were pyroxene group minerals, including diopsite ferrian, augite and diopsite. Almost all raw materials including quartz joined the reaction and transformed into pyroxene or glass phase in the sintering process, and different kinds of clays and feldspars had no impact on the final crystal phases. Flexural strength of the ceramic containing 40 wt.% steel slag in raw materials can reach 143 MPa at sintering temperature of 1210 °C and its corresponding water absorption, weight loss, linear shrinkage were 0.02%, 8.8%, 6.0% respectively. Pyroxene group minerals in ceramics would contribute to the excellent physical and mechanical properties

  11. Enhanced humification by carbonated basic oxygen furnace steel slag--I. Characterization of humic-like acids produced from humic precursors.

    Science.gov (United States)

    Qi, Guangxia; Yue, Dongbei; Fukushima, Masami; Fukuchi, Shigeki; Nie, Yongfeng

    2012-01-01

    Carbonated basic oxygen furnace steel slag (hereinafter referred to as "steel slag") is generated during iron and steel manufacturing and is often classified as waste. The effect of steel slag on humification process was investigated. Catechol, glycine and glucose were used as model humic precursors from degraded biowastes. To verify that humification occurred in the system, humic-like acids (HLAs) were isolated and characterized structurally by elemental analysis, FTIR spectra, solid-state CP-MAS (13)C NMR spectra, and TMAH-Py-GC/MS. Characteristics of the steel slag-HLA were compared with those of HLAs formed in the presence of zeolite and birnessite, and with that of mature compost humic acid. The results showed that steel slag-HLA, like zeolite- and birnessite-HLA, is complex organic material containing prominent aromatic structures. Steel slag substantially accelerated the humification process, which would be highly significant for accelerating the stabilization of biowastes during composting (e.g. municipal solid waste, sewage sludge, and food waste). PMID:22130079

  12. Characterization of slag product from plasma furnace for unsorted solid radioactive waste treatment

    International Nuclear Information System (INIS)

    The shaft furnace equipped with plasma-fuel burners for high temperature slagging treatment has been developed in for State Corp. Radon. A slag is considered as the final wasteform. From this point of view a slag formation mechanism, radionuclides immobilization and basic slag properties have been studied. Chemical and phase compositions of institutional and nuclear power station waste slags were determined. Some details of slag structure were investigated by infrared spectroscopy. A study of radionuclides distribution has shown that cesium and strontium are concentrated in the silicate slag constituent while iron and cobalt enter the metal fraction

  13. Physico-Chemical Characterization of Slag Waste Coming From IGCC Thermal Power Plant

    OpenAIRE

    Acosta, Anselmo; Aineto, Mónica; Iglesias, Isabel; Romero, Maximina; Rincón López, Jesús María

    2001-01-01

    The new gas installations of combined cycle (GICC) thermal power plants for production of electricity are more efficient than conventional thermal power plants, but they produce a high quantity of wastes in the form of slags and fly ashes. Nowadays, these by-products are stored within the production plants with, until now, no applications of recycling in other industrial processes. In order to evaluate the capability of these products for recycling in glass and ceramics inductory, an investig...

  14. Effect of additives in reducing ash sintering and slagging in biomass combustion applications

    OpenAIRE

    Wang, Liang

    2012-01-01

    The objective of this study was to investigate sintering and slagging behaviors of biofuels during combustion processes. Biofuels tested are derived from the agricultural sector, wood and furniture industry as well as from municipal sewage sludge. It was also the aim to test and evaluate additives that can prevent and abate biomass ash sintering by conducting laboratory and industrial scale tests.Sintering characteristics of sewage sludge ashes at elevated temperatures were investigated by me...

  15. Crystallization of synthetic coal-petcoke slag mixtures simulating those encountered in entrained bed slagging gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    Jinichiro Nakano; Seetharaman Sridhar; Tyler Moss; James Bennett; Kyei-Sing Kwong [National Energy Technology Laboratory, Pittsburgh, PA (United States)

    2009-09-15

    Commercial entrained bed slagging gasifiers use a carbon feedstock of coal, petcoke, or combinations of them to produce CO and H{sub 2}. These carbon sources contain mineral impurities that liquefy during gasification and flow down the gasification sidewall, interacting with the refractory linear and solidifying in the cooler zones of the gasifier. Proper slag flow is critical to good gasifier operation. A hot-stage confocal scanning laser microscope (CSLM) was used to analyze the kinetic behavior of slag crystallization for a range of synthetic coal-petcoke mixtures. On the basis of the observed precipitation during cool down studies in the 1200-1700{sup o}C temperature range, a time-temperature-transformation (TTT) diagram was created. The crystallization studies were conducted with a CO/CO{sub 2} (=1.8) corresponding to a gasification PO{sub 2} of approximately 10-8 atm at 1500{sup o}C. Ash chemistries were chosen such that they correspond to coal-petcoke feedstock mixtures with coal ash amounts of 0, 10, 30, 50, 70, and 100% (by weight), with the balance being petcoke ash. The TTT diagram exhibited two crystallization areas, one above and one below 1350{sup o}C. At the nose of the higher temperature curves, karelianite (V{sub 2}O{sub 3}) crystallization occurred and was fastest for a 30% coal-petcoke ash mixture. The second nose was located below 1350{sup o}C and had spinel-type phases that formed at 1200{sup o}C, in which preferred atomic occupation at the octahedral and tetrahedral sites varied depending upon the ash composition. At 1200{sup o}C, an Al-rich spinel formed for 100% coal slag and a Fe-rich spinel formed in petcoke-enriched slags. The addition of petcoke ash to coal ash promoted crystallization in the slag, with additional crystalline phases, such as V-rich spinel, forming at the lower temperatures. These phases were not predicted using commercially available databases. 30 refs., 18 figs.

  16. Vanadium bioavailability in soils amended with blast furnace slag

    International Nuclear Information System (INIS)

    Blast furnace (BF) slags are commonly applied as soil amendments and in road fill material. In Sweden they are also naturally high in vanadium. The aim of this study was to assess the vanadium bioavailability in BF slags when applied to soil. Two soils were amended with up to 29% BF slag (containing 800 mg V kg−1) and equilibrated outdoors for 10 months before conducting a barley shoot growth assay. Additional soil samples were spiked with dissolved vanadate(V) for which assays were conducted two weeks (freshly spiked) and 10 months (aged) after spiking. The BF slag vanadium was dominated by vanadium(III) as shown by V K-edge XANES spectroscopy. In contrast, results obtained by HPLC-ICP-MS showed that vanadium(V), the most toxic vanadium species, was predominant in the soil solution. Barley shoot growth was not affected by the BF slag additions. This was likely due to limited dissolution of vanadium from the BF slag, preventing an increase of dissolved vanadium above toxic thresholds. The difference in vanadium bioavailability among treatments was explained by the vanadium concentration in the soil solution. It was concluded that the vanadium in BF slag is sparingly available. These findings should be of importance in environmental risk assessment

  17. Vanadium bioavailability in soils amended with blast furnace slag.

    Science.gov (United States)

    Larsson, Maja A; Baken, Stijn; Smolders, Erik; Cubadda, Francesco; Gustafsson, Jon Petter

    2015-10-15

    Blast furnace (BF) slags are commonly applied as soil amendments and in road fill material. In Sweden they are also naturally high in vanadium. The aim of this study was to assess the vanadium bioavailability in BF slags when applied to soil. Two soils were amended with up to 29% BF slag (containing 800 mg V kg(-1)) and equilibrated outdoors for 10 months before conducting a barley shoot growth assay. Additional soil samples were spiked with dissolved vanadate(V) for which assays were conducted two weeks (freshly spiked) and 10 months (aged) after spiking. The BF slag vanadium was dominated by vanadium(III) as shown by V K-edge XANES spectroscopy. In contrast, results obtained by HPLC-ICP-MS showed that vanadium(V), the most toxic vanadium species, was predominant in the soil solution. Barley shoot growth was not affected by the BF slag additions. This was likely due to limited dissolution of vanadium from the BF slag, preventing an increase of dissolved vanadium above toxic thresholds. The difference in vanadium bioavailability among treatments was explained by the vanadium concentration in the soil solution. It was concluded that the vanadium in BF slag is sparingly available. These findings should be of importance in environmental risk assessment. PMID:25917693

  18. Vanadium bioavailability in soils amended with blast furnace slag

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, Maja A., E-mail: maja.larsson@slu.se [Department of Soil and Environment, Swedish University of Agricultural Sciences, P.O. Box 7014, 750 07 Uppsala (Sweden); Baken, Stijn, E-mail: stijn.baken@ees.kuleuven.be [Department of Earth and Environmental Sciences, Leuven University, Kasteelpark Arenberg 20 bus 2459, 3001 Leuven (Belgium); Smolders, Erik, E-mail: erik.smolders@ees.kuleuven.be [Department of Earth and Environmental Sciences, Leuven University, Kasteelpark Arenberg 20 bus 2459, 3001 Leuven (Belgium); Cubadda, Francesco, E-mail: francesco.cubadda@iss.it [Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161 (Italy); Gustafsson, Jon Petter, E-mail: jon-petter.gustafsson@slu.se [Department of Soil and Environment, Swedish University of Agricultural Sciences, P.O. Box 7014, 750 07 Uppsala (Sweden); Division of Land and Water Resources Engineering, KTH Royal Institute of Technology, Brinellvägen 28, 100 44 Stockholm (Sweden)

    2015-10-15

    Blast furnace (BF) slags are commonly applied as soil amendments and in road fill material. In Sweden they are also naturally high in vanadium. The aim of this study was to assess the vanadium bioavailability in BF slags when applied to soil. Two soils were amended with up to 29% BF slag (containing 800 mg V kg{sup −1}) and equilibrated outdoors for 10 months before conducting a barley shoot growth assay. Additional soil samples were spiked with dissolved vanadate(V) for which assays were conducted two weeks (freshly spiked) and 10 months (aged) after spiking. The BF slag vanadium was dominated by vanadium(III) as shown by V K-edge XANES spectroscopy. In contrast, results obtained by HPLC-ICP-MS showed that vanadium(V), the most toxic vanadium species, was predominant in the soil solution. Barley shoot growth was not affected by the BF slag additions. This was likely due to limited dissolution of vanadium from the BF slag, preventing an increase of dissolved vanadium above toxic thresholds. The difference in vanadium bioavailability among treatments was explained by the vanadium concentration in the soil solution. It was concluded that the vanadium in BF slag is sparingly available. These findings should be of importance in environmental risk assessment.

  19. Slags and ashes from municipal waste incineration in Poland - mineralogical and chemical composition

    Science.gov (United States)

    Kowalski, Piotr; Michalik, Marek

    2013-04-01

    In the next few years there will be a large change in the waste management system in Poland. Its primary aim will be reduction of the amount of landfilled waste by enhancing level of recycling, waste segregation, composting of biomass and incineration. The biggest investment during this transformation is construction of nine incinerators with assumed slags production around 200 thousand tons per year. Slag production is accompanied by fly ash generating. This ash can be a valuable raw material as fly ash from the power industry. Waste management system transformation will cause big increase in slag production in comparison to the present amount and will require taking necessary steps to ensure environmental safety. For this purpose, studies of slags and fly ashes in terms of environmental risk and potential impact on human health are significant. The object of the study are fly ashes and slags produced in the biggest municipal waste incineration power plant in Poland. Two series of samples obtained in municipal waste incineration process were studied in order to characterize mineralogical and chemical composition and to determine the concentrations of heavy metals and their possible negative environmental impact. Characteristics of these materials will be the basis for determining their value in application, for example in building industry. Mineralogical characteristic of slags was based on X-ray diffraction. Characteristic of structures and forms of occurrence of mineral phases was based on the optical microscopy and SEM imaging coupled with EDS analysis. Chemical analysis were performed using ICP-MS/ICP-AES methods. They allowed to follow variability between studied samples and gave basic information about metals. Metals in samples of slag and ashes are present as component of mineral phases and in the form of metallic inclusions in glass or minerals. Potentially hazardous concentrations for environment are observed for copper (330-4900ppm), zinc (1500-8100ppm

  20. New methods for investigating slag-heaps: integrating geoprospection, excavation and quantitative methods at Meroe, Sudan

    OpenAIRE

    Humphris, J. E.; Carey, C.

    2016-01-01

    This paper describes a multifaceted approach to the investigation of iron slag-heaps, focusing on one of the slag-heaps at the Royal City of Meroe in Sudan. This study marries together geoprospection data (gradiometry and electrical resistivity transects), topographic data and quantitative excavation data, to provide an analysis and comparison of the total volume, slag component and slag composition of a slag-heap. Significantly, the results demonstrate the limitations of using a topographic ...

  1. Thermodynamic modelling of alkali-activated slag cements

    International Nuclear Information System (INIS)

    Highlights: • A thermodynamic modelling analysis of alkali-activated slag cements is presented. • Thermodynamic database describes zeolites, alkali carbonates, C–(N–)A–S–H gel. • Updated thermodynamic model for Mg–Al layered double hydroxides. • Description of phase assemblages in Na2SiO3- and Na2CO3-activated slag cements. • Phase diagrams for NaOH-activated and Na2SiO3-activated slag cements are simulated. - Abstract: This paper presents a thermodynamic modelling analysis of alkali-activated slag-based cements, which are high performance and potentially low-CO2 binders relative to Portland cement. The thermodynamic database used here contains a calcium (alkali) aluminosilicate hydrate ideal solid solution model (CNASH-ss), alkali carbonate and zeolite phases, and an ideal solid solution model for a hydrotalcite-like Mg–Al layered double hydroxide phase. Simulated phase diagrams for NaOH- and Na2SiO3-activated slag-based cements demonstrate the high stability of zeolites and other solid phases in these materials. Thermodynamic modelling provides a good description of the chemical compositions and types of phases formed in Na2SiO3-activated slag cements over the most relevant bulk chemical composition range for these cements, and the simulated volumetric properties of the cement paste are consistent with previously measured and estimated values. Experimentally determined and simulated solid phase assemblages for Na2CO3-activated slag cements were also found to be in good agreement. These results can be used to design the chemistry of alkali-activated slag-based cements, to further promote the uptake of this technology and valorisation of metallurgical slags

  2. Leaching of cadmium, chromium, copper, lead, and zinc from two slag dumps with different environmental exposure periods under dynamic acidic condition.

    Science.gov (United States)

    Jin, Zhisheng; Liu, Taoze; Yang, Yuangen; Jackson, Daniel

    2014-06-01

    Over the past few decades, zinc smelting activities in Guizhou, China have produced numerous slag dumps, which are often dispersed on roadsides and hill slopes throughout the region. During periods of acid rain, these exposed slags release heavy metals into surface water bodies. A column leaching study was designed to test the potential release of the heavy metals cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn) under simulated acid rain events. Two slags with varying environmental exposure periods were packed in columns and subjected to leaching solutions of pH 3.5, 5.5, or DI H2O at intervals of 1, 7, 14, 28, 56d. Pulse concentrations of Cd in leachate were found above 5μg/L, Cr, Pb, and Zn >10μg/L, whereas, Cu reached 10μg/L. After five leaching events, the leachability (percentage of cumulative heavy metal leached after five leaching events as in its respective total concentration in slags) of Cd was 0.05 percent and 0.035 percent from the old and young slag, respectively. Cr (0.035 percent and 0.05 percent) was greater than Cu (0.002 percent and 0.005 percent) and Zn (0.006 percent and 0.003 percent), while the lowest leachability was observed for Pb (0.0005 percent and 0.0002 percent) from the old and young slags, respectively. Reaction rates (release amount of heavy metals in certain period of leaching) of heavy metals in the leachates demonstrated the sequence of Zn>Cr>Cd, Cu>Pb. Leaching release of heavy metals was jointly affected by the pH of leaching solution and mineral composition of slags (including chemical forms of Cd, Cr, Cu, Pb, and Zn). Environmental exposure period of slags, resulting in the alteration of minerals, could affect the release process of heavy metals in leaching as well. PMID:24632122

  3. Estimating phosphorus removal by steel slag in a flume experiment: effects of P concentrations and subsurface hydrological conditions

    Science.gov (United States)

    Chagas, I. S. P.; Huang, C. H.; Bowling, L. C.; Smith, D. R.

    2015-12-01

    Managing excessive phosphorus (P) is essential to reduce the incidence of environmental quality issues, such as eutrophication and harmful algal blooms. One potential strategy that have been developed with this purpose is the use of P sorption materials (PSMs) to sequester P from water systems, which is the objective of this study. We evaluated the performance of steel slag, an industrial by-product with high P sorption potential, through a flume experiment under two different subsurface hydrological conditions, drainage and saturation, and two input P concentrations, 1 and 5 ppm. The 10-m flume configuration, designed to simulate processes occurring in a drainage ditch, is comprised of four 2.5-m sequential segments: a sediment bed, a slag bed over sediment, a slag dam built over a slag bed, and another sediment bed. In the experiments, all four segments of the flume were set to either saturation or with a constant drainage (percolation) of 0.1 L/min for each segment. The experiment was conducted with a constant flow of elevated P water at 7.3 L/min for 4 hrs (adsorption run) and followed 24 hrs later by a 4-hr run of deionized water (desorption run) at the same inflow rate. The adsorption-desorption cycle was repeated three times with the same sediment and slag materials, to allow testing of the resilience of P sorption under different PSM placement, subsurface hydrologic and P loading conditions. Preliminary results from the first adsorption and desorption cycle show that the flow-through slag section sequestered the most P during the adsorption runs. By comparing the different P inflow concentrations analysis, it is clear that the removal process is concentration driven: 83% of the injected P was removed in the 5 ppm as compared to 46% in the 1 ppm saturation run. Because of the higher P removal at 5 ppm P inflow, slightly higher release was also observed during the desorption run. Analyses of the persistence of steel slag as PSM under repeated adsorption and

  4. Boron removal from molten silicon using sodium-based slags

    Institute of Scientific and Technical Information of China (English)

    Yin Changhao; Hu Bingfeng; Huang Xinming

    2011-01-01

    Slag refining,as an important option for boron removal to produce solar grade silicon (SOG-Si) from metallurgical grade silicon (MG-Si),has attracted increasing attention.In this paper,Na2CO3-SiO2 systems were chosen as the sodium-based refining slag materials for boron removal from molten silicon.Furthermore,the effect of Al2O3 addition for boron removal was studied in detail,which showed that an appropriate amount of Al2O3 can help retention of the basicity of the slags,hence improving the boron removal rate.

  5. Deoxidation and slag treatment of liquid steel. 1. Fundamental analysis

    International Nuclear Information System (INIS)

    By means of thermodynamic calculations and of special computer programs one determined the composition of nonmetallic inclusions (NI) developing in Kh18N9 stainless steel depending on alternative method of deoxidation by silicon, aluminium and titanium. One showed predominance of NI belonging to aluminium oxide base solid solution quality; one calculated oxygen partial pressure exerted on substances that corresponded to compositions of the selected slags under 1973 and 2273 K. One determined temperatures of liquidus surface of the mentioned slags and showed that four from mine slags under 1873 K turned to be liquid and homogeneous ones

  6. Leaching Kinetics of Praseodymium in Sulfuric Acid of Rare Earth Elements (REE) Slag Concentrated by Pyrometallurgy from Magnetite Ore

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chul-Joo; Yoon, Ho-Sung; Chung, Kyung Woo; Lee, Jin-Young; Kim, Sung-Don; Shin, Shun Myung [Korea Institute of Geoscience and Mineral Resources, Daejeon (Korea, Republic of); Kim, Hyung-Seop; Cho, Jong-Tae; Kim, Ji-Hye; Lee, Eun-Ji; Lee, Se-Il; Yoo, Seung-Joon [Seonam University, Asan (Korea, Republic of)

    2015-02-15

    A leaching kinetics was conducted for the purpose of recovery of praseodymium in sulfuric acid (H{sub 2}SO{sub 4}) from REE slag concentrated by the smelting reduction process in an arc furnace as a reactant. The concentration of H{sub 2}SO{sub 4} was fixed at an excess ratio under the condition of slurry density of 1.500 g slag/L, 0.3 mol H{sub 2}SO{sub 4}, and the effect of temperatures was investigated under the condition of 30 to 80 .deg. C. As a result, praseodymium oxide (Pr{sub 6}O{sub 1}1) existing in the slag was completely converted into praseodymium sulfate (Pr{sub 2}(SO{sub 4}){sub 3}·8H{sub 2}O) after the leaching of 5 h. On the basis of the shrinking core model with a shape of sphere, the first leaching reaction was determined by chemical reaction mechanism. Generally, the solubility of pure REEs decreases with the increase of leaching temperatures in sulfuric acid, but REE slag was oppositely increased with increasing temperatures. It occurs because the ash layer included in the slag is affected as a resistance against the leaching. By using the Arrhenius expression, the apparent activation energy of the first chemical reaction was determined to be 9.195 kJmol{sup -1}. In the second stage, the leaching rate is determined by the ash layer diffusion mechanism. The apparent activation energy of the second ash layer diffusion was determined to be 19.106 kJmol{sup -1}. These relative low activation energy values were obtained by the existence of unreacted ash layer in the REE slag.

  7. Leaching Kinetics of Praseodymium in Sulfuric Acid of Rare Earth Elements (REE) Slag Concentrated by Pyrometallurgy from Magnetite Ore

    International Nuclear Information System (INIS)

    A leaching kinetics was conducted for the purpose of recovery of praseodymium in sulfuric acid (H2SO4) from REE slag concentrated by the smelting reduction process in an arc furnace as a reactant. The concentration of H2SO4 was fixed at an excess ratio under the condition of slurry density of 1.500 g slag/L, 0.3 mol H2SO4, and the effect of temperatures was investigated under the condition of 30 to 80 .deg. C. As a result, praseodymium oxide (Pr6O11) existing in the slag was completely converted into praseodymium sulfate (Pr2(SO4)3·8H2O) after the leaching of 5 h. On the basis of the shrinking core model with a shape of sphere, the first leaching reaction was determined by chemical reaction mechanism. Generally, the solubility of pure REEs decreases with the increase of leaching temperatures in sulfuric acid, but REE slag was oppositely increased with increasing temperatures. It occurs because the ash layer included in the slag is affected as a resistance against the leaching. By using the Arrhenius expression, the apparent activation energy of the first chemical reaction was determined to be 9.195 kJmol-1. In the second stage, the leaching rate is determined by the ash layer diffusion mechanism. The apparent activation energy of the second ash layer diffusion was determined to be 19.106 kJmol-1. These relative low activation energy values were obtained by the existence of unreacted ash layer in the REE slag

  8. Outcomes of experimental researches on stainless steel decontamination from radioactive contamination using electric slag remelting method

    International Nuclear Information System (INIS)

    Full text: Institute of Atomic Energy prepared and conducted the experiments the purpose of researching a possibility of applying of stainless steel electric slag remelting for its decontamination from radioactive contamination. The activities were conducted at participating of the specialists of Kurgan State University, Kurgan (Russian Federation). A stand, which includes the electroslag furnace (power - 150 kW, current - to 3000 A) and auxiliary equipment (the system of common and special ventilation, system of remote control, system of parameters measuring and registering and others) was created to conduct the experiments. The properties of slag compositions were researched in the course of experiments preparation. Oxide (CaO-Al2O3 - CaO-SiO2 - MgO-B2O3) and fluoride-oxide (CaF2-SiO2 - MgF2-SiO2) slag systems and some their modifications were chosen to research physical and chemical properties. Physical and chemical properties of the slag systems were experimentally researched and it included: measuring of surface tension using the method of maximum pressure in a gas bubble (at the same time density was measured); measuring of slag alloys electrical conductivity; measuring of melt volt-ampere characteristics. The flue tubes of high temperature reactor gas cooling KET technological channels were chosen as a source of radioactive contaminated stainless steel. This reactor is meant for testing of the fuel pin and FA of the nuclear pulse propulsion. Decontamination effect for all the remelted flue tubes was indirectly confirmed by the outcomes of measuring of radioactive radiation dose rate of the materials, extracted of the crystallizer after experiments finishing. The outcomes of the experiments show that the following processes pass at electroslag remelting of radioactively contaminated steel: uranium extraction from steel; uranium transfer from steel to slag; saving or insignificant modification of steel initial composition; radionuclides deposing on the special

  9. Hydration mechanism of a cementitious material prepared with Si-Mn slag

    Science.gov (United States)

    Zhang, Xu-Fang; Ni, Wen; Wu, Jun-Yu; Zhu, Li-Ping

    2011-04-01

    A cementitious material was prepared by mixing 80wt% Si-Mn slag powder, 10wt% lime, and 10wt% anhydrite. The compressive strength of mortar samples reaches 51.48 MPa after 28 d curing. The analyses of X-ray diffraction (XRD) and scanning electron microscopy (SEM) show that much ettringite is formed in the sample cured for 3 d, and C-S-H gel increases rapidly during subsequent curing. Nuclear magnetic resonance (NMR) analysis of 29Si and 27Al and infrared spectroscopy (IR) analysis show that aluminum decomposition from tetrahedral network of the slag glass and its subsequent migration and re-combination play an important role in the process of hydration and strength development of the samples.

  10. Reaction between Steel-Making Slag and Carbonaceous Materials While Mixing with High Density Polyethylene

    Science.gov (United States)

    Hong, Lan; Sahajwalla, Veena

    2016-01-01

    Since the beginning of the extensive applications in numerous high temperature processes such as iron- and steel-making, coke-making etc. partly in the place of coke, the investigation into the reaction mechanism of waste plastics has become increasingly necessary. In this paper a fundamental study on the behavior of a typical component of waste plastics, high density polyethylene (HDPE), in a mixture with coke at a 1:1 ratio in mass base was conducted during the reaction with iron oxide in steel-making slag at 1823 K and was compared with coke and graphite. The reaction mechanism of carbonaceous materials was analyzed based on the contents of CO and CO2 in the off-gas monitored by an infrared (IR) gas analyzer. It is clear from the results that the reaction of HDPE and coke mixture with steel-making slag approached equilibrium of the Boudouard reaction more quickly and closely than coke or graphite.

  11. The recovery of Zn and Pb and the manufacture of lightweight bricks from zinc smelting slag and clay.

    Science.gov (United States)

    Hu, Huiping; Deng, Qiufeng; Li, Chao; Xie, Yue; Dong, Zeqin; Zhang, Wei

    2014-04-30

    Novel lightweight bricks have been produced by sintering mixes of zinc smelting slag and clay. A two-stage sintered process has been proposed to recovery of Zn and Pb and reutilization of the zinc smelting slag. In the first stage of the process, called reduction and volatilization procedure, zinc and lead were reduced by the carbon contained in the zinc smelting slag and volatilized into the dust, and the dust can be used as a secondary zinc resource. In the second stage of the process, called oxidation sintering procedure, a lightweight brick was produced. Samples containing up to 60 wt.% zinc smelting slag and 40 wt.% kaolin clay were reduced at 1050°C for 6h, and then sintered at 1050°C for 4h. The recoveries of Zn and Pb from the brick are 94.5 ± 0.6% and 97.6 ± 0.2%, respectively. Low bulk density (1.42 g cm(-3)) and relatively high compressive strength (2 2MPa) sintered bricks were produced, and the leaching toxicity of the sintered bricks was below the regulatory thresholds of Chinese National Standards. PMID:24637448

  12. Numerical Investigation of Slag Behavior for RSRM

    Science.gov (United States)

    Liaw, P.; Chen, Y.-S.; Shang, H.; Shih, M.; Doran, D.; Stewart, E.

    1996-01-01

    It is known that the flow field of the redesigned solid rocket motor (RSRM) is very complicated due to the complex characteristics of turbulent multi-phase flow, chemical reaction, particle combustion, evaporation, breakup and agglomeration etc. It requires multi-phase calculations, chemical reaction simulation, and particle combustion, evaporation, and breakup models to obtain a better understanding of thermophysics for the RSRM design using numerical methods. Also, the slag buildup due to the molten particles is another factor affecting the performance of the RSRM. To achieve this goal, the volume of fluid (VOF) method is used to capture the free surface motion so as to simulate the accumulation of the molten particles (slag) of the RSRM. A finite rate chemistry model is used to simulate the chemical reaction effects. For multi-phase calculations, the Hermsen combustion model is used for the aluminum particle combustion analysis and the Taylor Analogy Breakup (TAB) model is used for the particle breakup analysis. An interphase mas-exchange model introduced by Spalding is used for the evaporation calculation. The particle trajectories are calculated using a one-step implicit method for several groups of particle sizes by which the drag forces and heat fluxes are then coupled with the gas phase equations. The preliminary results predicted a reasonable physical simulation of the particle effects using a simple two dimensional solid rocket motor configuration. It shows that the AL/AL2O3 particle sizes are reduced due to the combustion, evaporation, and breakup. The flow field is disturbed by the particles. Mach number distributions in the nozzle are deformed due to the effect of particle concentrations away from the center line.

  13. Study of Chromium Oxide Activities in EAF Slags

    Science.gov (United States)

    Yan, Baijun; Li, Fan; Wang, Hui; Sichen, Du

    2016-02-01

    The activity coefficients of chromium in Cu-Cr melts were determined by equilibrating liquid copper with solid Cr2O3 in CO-CO2 atmosphere. The temperature dependence of the activity coefficients of chromium in Cu-Cr melts could be expressed as lg γ_{Cr}(s)^{0} = { 3 2 5 9( ± 1 8 6} )/T - 0. 5 9( { ± 0. 1} ). Based on the above results, the activities of bivalent and trivalent chromium oxide in some slags at 1873 K (1600 °C) were measured. The slags were equilibrated with Cu-Cr melts under two oxygen partial pressures ( {p_{O}_{ 2} }} } = 6.9 × 10-4 and 1.8 × 10-6 Pa, respectively). The morphology of the quenched slags and the solubility of chromium oxide in the melts were investigated by EPMA, SEM, and XRD. Under both oxygen partial pressures, the slags were saturated by the solid solution MgAl2- x Cr x O4- δ . At the low oxygen partial pressure (1.8 × 10-6 Pa), the content of Cr in the liquid phase varied from 0.4 to 1.6 mass pct with the total Cr content in the slags increasing from 1.3 to 10.8 mass pct. At the high oxygen partial pressure (6.9 × 10-4 Pa), the content of Cr in the liquid phase decreased to the level of 0.2 to 0.6 mass pct. Both the activities of CrO and Cr2O3 in slag were found to increase approximately linearly with the increase of the total Cr content in slag. While the oxygen partial pressure had minor effect on the activity of Cr2O3 in the slag, it had significant effect on the activity of CrO.

  14. Investigation on the Potentials of Cupola Furnace Slag in Concrete

    OpenAIRE

    Stephen Adeyemi Alabi; Joseph O. Afolayan

    2013-01-01

    The compressive strength of the concrete designed using blast cupola furnace slag and granulated cupola slag as a coarse aggregate and partial replacement for cement was investigated. A series of experimental studies were conducted involve concrete production in two stages. The first stage comprised of normal aggregate concrete (NAC) produced with normal aggregates and 100% ordinary Portland cement (OPC). Meanwhile, the second stage involved production of concrete comprising of cupola furnace...

  15. Desulfurization ability of refining slag with medium basicity

    Science.gov (United States)

    Yu, Hui-xiang; Wang, Xin-hua; Wang, Mao; Wang, Wan-jun

    2014-12-01

    The desulfurization ability of refining slag with relative lower basicity ( B) and Al2O3 content ( B = 3.5-5.0; 20wt%-25wt% Al2O3) was studied. Firstly, the component activities and sulfide capacity ( C S) of the slag were calculated. Then slag-metal equilibrium experiments were carried out to measure the equilibrium sulfur distribution ( L S). Based on the laboratorial experiments, slag composition was optimized for a better desulfurization ability, which was verified by industrial trials in a steel plant. The obtained results indicated that an MgO-saturated CaO-Al2O3-SiO2-MgO system with the basicity of about 3.5-5.0 and the Al2O3 content in the range of 20wt%-25wt% has high activity of CaO ( a CaO), with no deterioration of C S compared with conventional desulfurization slag. The measured L S between high-strength low-alloyed (HSLA) steel and slag with a basicity of about 3.5 and an Al2O3 content of about 20wt% and between HSLA steel and slag with a basicity of about 5.0 and an Al2O3 content of about 25wt% is 350 and 275, respectively. The new slag with a basicity of about 3.5-5.0 and an Al2O3 content of about 20wt% has strong desulfurization ability. In particular, the key for high-efficiency desulfurization is to keep oxygen potential in the reaction system as low as possible, which was also verified by industrial trials.

  16. Applicability of Carbonated Electric Arc Furnace Slag to Mortar

    Science.gov (United States)

    Yokoyama, S.; Arisawa, R.; Hisyamudin, M. N. N.; Murakami, K.; Maegawa, A.; Izaki, M.

    2012-03-01

    Authors have been studying the absorption of CO2 in the steelmaking slag. In this study, an application of the electric arc furnace slag after the carbonation to admixture of mortar was investigated with the JIS (A6206-1997) method for ground granulated blast-furnace slag for concrete. The percent flows for the test mortar were smaller than that for the standard mortar. The percent flow of the carbonated slag whose average particle size of more than approximately 4 μm increased with an increase in the average size of the particles. Because the compressive strengths of the test mortar cured for 91 days were almost the same as those cured 28 days, the slag after the carbonation was thought not to have self-hardening property for a medium and long term. The compressive strength for the test mortar was almost unchanged within a range of approximately 2 to 7 μm of the average particle size, and it in this range was highest. The activity indexes for the test mortar prepared with the slag after the carbonation ranged from approximately 40 to 60 %.

  17. Removal of cadmium and chromium ions by using slag media

    International Nuclear Information System (INIS)

    This study was carried out to investigate the feasibility and removal efficiency of Cd (II) and Cr(III) ions removal from the simulated wastewater solution by using slag media type filter. The results of the slag filter were compared to conventional sand filter at the point of view of effluent quality and removal performance. The obtained effective size and coefficient uniformity were 0.45mm and 1.67 in slag, 0.46mm and 1.35 in sand respectively. At pH 7, imulated wastewater, 100mg Cd/l was passed through both filter columns. The slag filter showed 60 to 80 percent removal efficiency of the initial Cd concentration, while the sand filter showed only 5 to 10 percent. Optimum pH value for Cd removal showed 7, obtained optimum back wash frequency of slag column was 1.5 times less than of sand. With the simulated wastewater having ionic concentration of pH 7 the removal efficiency of the slag column and metal concentration of 100ml/l revealed 99.7 percent during 62 hrs, while that of the sand column was 28.5 percent. (Author)

  18. Applicability of Carbonated Electric Arc Furnace Slag to Mortar

    International Nuclear Information System (INIS)

    Authors have been studying the absorption of CO2 in the steelmaking slag. In this study, an application of the electric arc furnace slag after the carbonation to admixture of mortar was investigated with the JIS (A6206-1997) method for ground granulated blast-furnace slag for concrete. The percent flows for the test mortar were smaller than that for the standard mortar. The percent flow of the carbonated slag whose average particle size of more than approximately 4 μm increased with an increase in the average size of the particles. Because the compressive strengths of the test mortar cured for 91 days were almost the same as those cured 28 days, the slag after the carbonation was thought not to have self-hardening property for a medium and long term. The compressive strength for the test mortar was almost unchanged within a range of approximately 2 to 7 μm of the average particle size, and it in this range was highest. The activity indexes for the test mortar prepared with the slag after the carbonation ranged from approximately 40 to 60%.

  19. Effects of Slag Ejection on Solid Rocket Motor Performance

    Science.gov (United States)

    Whitesides, R. Harold; Purinton, David C.; Hengel, John E.; Skelley, Stephen E.

    1995-01-01

    In past firings of the Reusable Solid Rocket Motor (RSRM) both static test and flight motors have shown small pressure perturbations occurring primarily between 65 and 80 seconds. A joint NASA/Thiokol team investigation concluded that the cause of the pressure perturbations was the periodic ingestion and ejection of molten aluminum oxide slag from the cavity around the submerged nozzle nose which tends to trap and collect individual aluminum oxide droplets from the approach flow. The conclusions of the team were supported by numerous data and observations from special tests including high speed photographic films, real time radiography, plume calorimeters, accelerometers, strain gauges, nozzle TVC system force gauges, and motor pressure and thrust data. A simplistic slag ballistics model was formulated to relate a given pressure perturbation to a required slag quantity. Also, a cold flow model using air and water was developed to provide data on the relationship between the slag flow rate and the chamber pressure increase. Both the motor and the cold flow model exhibited low frequency oscillations in conjunction with periods of slag ejection. Motor and model frequencies were related to scaling parameters. The data indicate that there is a periodicity to the slag entrainment and ejection phenomena which is possibly related to organized oscillations from instabilities in the dividing streamline shear layer which impinges on the underneath surface of the nozzle.

  20. Analogue experimental study on centrifugal-air blast granulation for molten slag

    International Nuclear Information System (INIS)

    Blast furnace slag is a by-product in iron and steel production process which has a high yield with extremely high discharge temperature. Aiming at energy and water saving as well as emission reduction, dry granulation technique appears to be a good application for the treatment of blast furnace slag. In this study, a granulation technique combining a high-speed rotating cup with air blast is proposed. The performance of this design was investigated by adopting a mixture of rosin and paraffin wax as the analogue of blast furnace slag. The effects of rotating speed of the atomizer, liquid flow rate and blast air flow rate on particle size, particle mass distribution and fiber mass fraction were studied. The effect of the function of air blast on the granulation performance was particularly discussed. The results showed that at a higher rotating speed and a smaller liquid flow rate, smaller particles can be easily obtained, yet the fiber mass fraction also increases. However, the increasing blast air leads to the increase of particle size and fiber mass fraction. For the operating conditions tested in this study, over 60% of total mass of particles fall within the size range of 0.5–1 mm, which means that the present system has a good performance in centrifugal granulation

  1. Blast furnace slag-cement grout blends for the immobilization of technetium-containing wastes

    International Nuclear Information System (INIS)

    Mixed low-level radioactive and chemically toxic process treatment wastes from the Portsmouth Gaseous Diffusion Plant are stabilized by solidification in cement-based grouts. Conventional portland cement and fly ash grouts are shown to be very effective for retention of hydrolyzable heavy metals (including lead, cadmium, uranium, and nickel), but are marginally acceptable for retention of radioactive 99Tc (which is present in the waste as the highly mobile pertechnate anion). Addition of ground blast furnace slag to the grout is shown to reduce the effective diffusivity of technetium by several orders of magnitude; retention of technetium is improved by decreasing the waste loading in the grout or by increasing the proportion of blast furnace slag in the grout dry mix. The selective effect of slag is believed to be due to its ability to reduce Tc(VIII) to the less soluble Tc(IV) species. The addition of other reductive grout admixtures (e.g., sodium sulfide, ferrous ion, and powdered iron metal) also appear to improve the retention of technetium in grout. 31 refs., 2 figs., 25 tabs

  2. Chemical fractionation of some natural radionuclides in a soil contaminated by slags

    International Nuclear Information System (INIS)

    To investigate the chemical fractionation of 238U, 226Ra, 210Pb, and 228Ra in soils contaminated by slags from coal firing and from pyrite roasting, a sequential extraction method (modified Tessier procedure) has been applied. The following fractions were each extracted: 1, easily exchangeable; 2, bound to carbonates; 3, bound to iron-manganese oxides; 4; bound to organic matter; 5, persistently bound; 6, residual. In addition, the extractants were also analyzed for the insoluble matrix elements Al and Fe to provide some information on the effect of each extraction step on the dissolution of the matrix. The results show that the percentage amounts of these radio-nuclide in fractions 1 (238U and 210Pb released from the slag by the iron-manganese oxide extractant are subsequently reabsorbed rapidly to a considerable extent by soil minerals and thus do not appear in the iron-manganese oxide fraction 3 but rather in fractions 4 and 6. As a result of such redistribution processes, it will be almost impossible to predict quantitatively the chemical fractionation of radionuclides in contaminated soils by investigating pure slags only. 24 refs., 2 figs., 2 tabs

  3. The optimisation of the viscosity of lubricating slags used in the continuous casting of steel

    Science.gov (United States)

    Gheorghiu, Csaba Attila; Hepuť, Teodor; Popa, Erika

    2016-06-01

    In the steel continuous casting process, the mould lubrication has a very important technological role, with direct effects on the continuous cast blank quality. The lubrication process is directly influenced by the synthetic flux viscosity (slag thickness), which is determined on its turn by the chemical composition and the temperature. The researches made aimed to establish some correlation relationships between the viscosity, chemical composition and temperature, analytically and graphically expressed, by processing the data in the Matlab program. Based on these correlations the best chemical compositions of the lubrication fluxes are established.

  4. Mass Transfer Behavior of Phosphorus from the Liquid Slag Phase to Solid 2CaO·SiO2 in the Multiphase Dephosphorization Slag

    Science.gov (United States)

    Xie, Senlin; Wang, Wanlin; Luo, Zhican; Huang, Daoyuan

    2016-06-01

    The mass transfer behavior of phosphorus in the multiphase dephosphorization slag at 1623 K (1350 °C) is investigated in this article by adding the reagent P2O5 powders into the CaO-FeOt-SiO2 slag saturated with a directly precipitated 2CaO·SiO2 phase. The results show that the phosphorus was first quickly dissolved and transferred from the liquid slag to the precipitated solid 2CaO·SiO2 particle; then it reacted with the solid 2CaO·SiO2 particle to form (2CaO·SiO2-3CaO·P2O5) solid solution at the edge of a large solid particle. The further diffusion of phosphorus from the formed (2CaO·SiO2-3CaO·P2O5) solid solution reaction layer into the core of the 2CaO·SiO2 particle is the limiting step during the enrichment-phosphorus process. It is observed that the enrichment-phosphorus process is changed when the amount of added P2O5 content is increased and the formed solid solution phase is torn and peeled off from the surface of the 2CaO·SiO2 particle. In addition, the study shows that the solid solution structure is changed and becomes more compacted with the addition of P2O5 content, leading to the increment of solid solution density.

  5. Chemical durability of slag produced by thermal plasma melting of low-level miscellaneous solid wastes. Effects of slag composition

    International Nuclear Information System (INIS)

    Low-level radioactive miscellaneous solid wastes are generated from commercial operation of nuclear power plants and will be generated from decommissioning of nuclear power plants in future. Static leaching tests were carried out in deionized water of 10degC on slag obtained by thermal plasma melting of simulating materials of the miscellaneous solids wastes with surrogate elements of radionuclides. It is found that logarithm of normalized elemental mass loss from the slag is proportional to the basicity represented by mole fractions of main structural oxides of the slag, such as SiO2, Al2O3, CaO, FeO and MgO. The range of static leaching rates from the slag is determined based on the above results and the basicity range of the miscellaneous solid wastes. Then we compared the leaching rates form the slag and from high level waste glasses. On these grounds, we concluded that the slag obtained by thermal plasma melting of miscellaneous solid wastes can stabilize radio-nuclides in it by no means inferior to the high level waste glasses. (author)

  6. Study on aluminothermic reduction of V2O5: effect of slag chemistry

    International Nuclear Information System (INIS)

    Vanadium alloys are promising candidate materials for structural components of fusion reactors because of their superior high temperature thermal and physical properties, low cross section to neutrons, low activation properties and good resistance against neutron irradiation. Increased level of interstitial impurities like O and N in vanadium is known to have several detrimental effects on the workability and weldability of alloys. Activation consideration also place limitation on N content. In the present study, systematic work is done with the use of modern analytical techniques to better understand the science of the thermit process of vanadium so that it can be applied efficiently at bigger scale. In literature, generally CaO is used as a fluxing agent, to minimize excess heat and also for good slag metal separation in aluminothermy. Normally heat sinks are added in order to control the heat of reaction. This study shows that apart from the quantity, it is the nature of heat sink/flux, which plays an important role in controlling the heat of reaction, which subsequently result in better yield and quality of the product. Effect of various parameters like amount of heat sink/flux, nature of heat sink, excess aluminum and particle size of Al has been studied. Heat sink materials/ fluxes were added to control the vigorous nature of the reaction and a corresponding increase in slag volume (resulting in thicker slag layer) was also intended. Increased slag volume was expected to decrease the interaction of air with the molten metal thereby resulting in minimization of nitrogen in the final metal. This aspect is examined in detail in the present work. It will help in better understanding of the process as far as the contribution of nitrogen in thermit from air and starting material. In general, during the aluminothermic reduction, MgO walled reactors is used, but in this study it is shown that substantial amount of MgO also participate in the aluminothermy. The role

  7. Desulfurization ability of refining slag with medium basicity

    Institute of Scientific and Technical Information of China (English)

    Hui-xiang Yu; Xin-hua Wang; Mao Wang; Wan-jun Wang

    2014-01-01

    The desulfurization ability of refining slag with relative lower basicity (B) and Al2O3 content (B=3.5−5.0;20wt%−25wt%Al2O3) was studied. Firstly, the component activities and sulfide capacity (CS) of the slag were calculated. Then slag−metal equilibrium experiments were carried out to measure the equilibrium sulfur distribution (LS). Based on the laboratorial experiments, slag composition was optimized for a better desulfurization ability, which was verified by industrial trials in a steel plant. The obtained results indicated that an MgO-saturated CaO−Al2O3−SiO2−MgO system with the basicity of about 3.5−5.0 and the Al2O3 content in the range of 20wt%−25wt%has high activity of CaO (aCaO), with no deterioration of CS compared with conventional desulfurization slag. The measured LS between high-strength low-alloyed (HSLA) steel and slag with a basicity of about 3.5 and an Al2O3 content of about 20wt%and between HSLA steel and slag with a basicity of about 5.0 and an Al2O3 content of about 25wt%is 350 and 275, respectively. The new slag with a basicity of about 3.5−5.0 and an Al2O3 content of about 20wt%has strong desulfurization ability. In particular, the key for high-efficiency desulfurization is to keep oxygen potential in the reaction system as low as possible, which was also verified by industrial trials.

  8. Energy-conscious production of titania and titanium powders from slag

    Science.gov (United States)

    Middlemas, Scott C.

    Titanium dioxide (TiO2) is used as a whitening agent in numerous domestic and technological applications and is mainly produced by the high temperature chloride process. A new hydrometallurgical process for making commercially pure TiO2 pigment is described with the goal of reducing the necessary energy consumption and CO2 emissions. The process includes alkaline roasting of titania slag with subsequent washing, HCl leaching, solvent extraction, hydrolysis, and calcination stages. The thermodynamics of the roasting reaction were analyzed, and the experimental parameters for each step in the new process were optimized with respect to TiO 2 recovery, final product purity, and total energy requirements. Contacting the leach solution with a tertiary amine extractant resulted in complete Fe extraction in a single stage and proved effective in reducing the concentration of discoloring impurities in the final pigment to commercially acceptable levels. Additionally, a new method of producing Ti powders from titania slag is proposed as a potentially more energy efficient and lower cost alternative to the traditional Kroll process. Thermodynamic analysis and initial experimental results validate the concept of reducing titanium slag with a metal hydride to produce titanium hydride (TiH2) powders, which are subsequently purified by leaching and dehydrided to form Ti powders. The effects of reducing agent type, heating time and temperature, ball milling, powder compaction, and eutectic chloride salts on the conversion of slag to TiH2 powders were determined. The purification of reduced powders through NH4Cl, NaOH, and HCl leaching stages was investigated, and reagent concentration, leaching temperature, and time were varied in order to determine the best conditions for maximum impurity removal and recovery of TiH2. A model plant producing 100,000 tons TiO2 per year was designed that would employ the new method of pigment manufacture. A comparison of the new process and the

  9. Separation of Iron Phase and P-Bearing Slag Phase from Gaseous-Reduced, High-Phosphorous Oolitic Iron Ore at 1473 K (1200 °C) by Super Gravity

    Science.gov (United States)

    Gao, Jintao; Zhong, Yiwei; Guo, Lei; Guo, Zhancheng

    2016-04-01

    In situ observation on the morphology evolution and phosphorous migration of gaseous-reduced, high-phosphorous oolitic iron ore during the melting process was carried out with a high-temperature confocal scanning laser microscope. The results showed that 1473 K (1200 °C) was a critical temperature at which the gangue minerals started to form into the slag phase while the iron grains remained in a solid state; in addition, the phosphorus remained in the slag phase. Since the separation of iron grains and P-bearing slag was not achieved at the low temperature under the conventional conditions, separate experiments of the iron phase and the P-bearing slag phase from gaseous-reduced, high-phosphorous oolitic iron ore at 1473 K (1200 °C) by super gravity were carried out in this study. Based on the iron-slag separation by super gravity, phosphorus was removed effectively from the iron phase at the temperature below the melting point of iron. Iron grains moved along the super-gravity direction, joined, and concentrated as the iron phase on the filter, whereas the slag phase containing apatite crystals broke through the barriers of the iron grains and went through the filter. Consequently, increasing the gravity coefficient was definitely beneficial for the separation of the P-bearing slag phase from the iron phase. With the gravity coefficient of G = 1200, the mass fractions of separated slag and iron phases were close to their respective theoretical values, and the mass fraction of MFe in the separated iron phase was up to 98.09 wt pct and that of P was decreased to 0.083 wt pct. The recovery of MFe in the iron phase and that of P in the slag phase were up to 99.19 and 95.83 pct, respectively.

  10. Maximizing carbon uptake and performance gain in slag-containing concretes through early carbonation

    Science.gov (United States)

    Monkman, Sean

    -cured concrete employed carbonated ladle slag as a fine aggregate. It is estimated that close to two million tonnes of CO2 could be sequestered into precast concrete annually in US and Canada if four building products, namely blocks, pavers, cement boards and fibreboards, are processed using carbonation-curing. The approximately 110 million tonnes of cement produced in North America annually are associated with emissions of about 74 million tonnes of CO2. The sequestration from carbonation-curing would represent an emission reduction of 2.7%. The capacity for carbon storage into precast concretes can be further increased if carbonation-treated aggregates are used.

  11. Steel Slag as an Iron Fertilizer for Corn Growth and Soil Improvement in a Pot Experiment

    Institute of Scientific and Technical Information of China (English)

    WANG Xian; CAI Qing-Sheng

    2006-01-01

    The feasibility of steel slag used as an iron fertilizer was studied in a pot experiment with corn. Slag alone or acidified slag was added to two Fe-deficient calcareous soils at different rates. Results showed that moderate rates (10 and 20 g kg-1)of slag or acidified slag substantially increased corn dry matter yield and Fe uptake. Application of steel slag increased the residual concentration of ammonium bicarbonate-diethylenetriamine pentaacetic acid (AB-DTPA) extractable Fe in the soils. The increase of extractable Fe was usually proportional to the application rate, and enhanced by the acidification of slag. Steel slag appeared to be a promising and inexpensive source of Fe to alleviate crop Fe chlorosis in Fe-deficient calcareous soils.

  12. Preparation of calcium silicate absorbent from iron blast furnace slag.

    Science.gov (United States)

    Brodnax, L F; Rochelle, G T

    2000-09-01

    Calcium silicate hydrate (CSH) solids were prepared from hydrated lime and iron blast furnace slag in an aqueous agitated slurry at 92 degrees C. While it was hoped a minimal lime/slag ratio could be used to create near-amorphous CSH, the surface area of the product improved by increasing the lime/slag weight ratio to 2. The addition of gypsum to the lime/slag system dramatically improved the formation of surface area, creating solids with 139 m2/g after 30 hr of reaction when only a minimal amount of lime was present. The SO2 reactivity of solids prepared with gypsum greatly exceeded that of hydrated lime, achieving greater than 70-80% conversion of the alkalinity after 1 hr of reaction with SO2. The use of CaCl2 as an additive to the lime/slag system, in lieu of gypsum, also produced high-surface-area solids, 115 m2/g after 21 hr of reaction. However, the SO2 reactivity of these sorbents was relatively low given the high surface area. This emphasized that the correlation between surface area and SO2 reactivity was highly dependent on the solid phase, which was subsequently dependent on slurry composition. PMID:11055162

  13. Analysis of the Optimum Usage of Slag for the Compressive Strength of Concrete

    OpenAIRE

    Han-Seung Lee; Xiao-Yong Wang; Li-Na Zhang; Kyung-Taek Koh

    2015-01-01

    Ground granulated blast furnace slag is widely used as a mineral admixture to replace partial Portland cement in the concrete industry. As the amount of slag increases, the late-age compressive strength of concrete mixtures increases. However, after an optimum point, any further increase in slag does not improve the late-age compressive strength. This optimum replacement ratio of slag is a crucial factor for its efficient use in the concrete industry. This paper proposes a numerical procedu...

  14. Evaluation and Characterization of Plasma Sprayed Cu Slag-Al Composite Coatings on Metal Substrates

    OpenAIRE

    S. Mantry; Jha, B. B.; Satapathy, A.

    2013-01-01

    Copper slag is a waste product obtained during matte smelting and refining of copper. The present work explores the coating potential of copper slag by plasma spraying. This work shows that copper slag is eminently coatable. An attempt has been made in the present investigation to use the composites coatings of copper slag and Al powder in suitable combination on aluminium and mild steel substrates in order to improve the surface properties of these ductile metal-alloy substrates. When premix...

  15. Development of Glass Ceramics Made From Ferrous Tailings and Slag in China

    Institute of Scientific and Technical Information of China (English)

    LIU Cheng-jun; SHI Pei-yang; ZHANG Da-yong; JIANG Mao-fa

    2007-01-01

    A great amount of ferrous tailings and slag cause severe damage to the ecological environment, which must be reclaimed and utilized. The composition, type, and characteristics of ferrous tailings and slag in China were introduced. The research status and the application outlook of glass ceramics made from ferrous tailings and slag were discussed. Glass ceramics made from ferrous tailings and slag can be applied to various fields, and it will be environmentally conscious materials in the 21st century.

  16. Petrogenetic characteristics of molten slag from the pyrolysis/melting treatment of MSW.

    Science.gov (United States)

    Saffarzadeh, Amirhomayoun; Shimaoka, Takayuki; Motomura, Yoshinobu; Watanabe, Koichiro

    2009-03-01

    MSW slag materials derived from four pyrolysis melting plants in Japan were studied from the viewpoint of petrology in order to discriminate the glass and mineral phases and to propose a petrogenetic model for the formation process of molten slag. Slag material is composed of two major components: melt and refractory products. The melt products that formed during the melting process comprise silicate glass, and a suite of minerals as major constituents. The silicate glass is essentially composed of low and high silica glass members (typically 30% and 50% of SiO(2), respectively), from which minerals such as spinels, melilite, pseudowollastonite, and metallic inclusions have been precipitated. The refractory products consist mainly of pieces of metals, minerals and lithic fragments that survived through the melting process. Investigations demonstrated that the low silica melts (higher Ca and Al contents) were produced at upper levels of high temperature combustion chamber HTCC, at narrower temperature ranges (1250-1350 degrees C), while the high silica melts formed at broader temperature ranges (1250-1450 degrees C), at the lower levels of HTCC. The recent temperature ranges were estimated by using CaOAl(2)O(3)SiO(2) (CAS) ternary liquidus diagram that are reasonably consistent with those reported for a typical combustor. It was also understood that the samples with a higher CaO/SiO(2) ratio (>0.74-0.75) have undergone improved melting, incipient crystallization of minerals, and extensive homogenization. The combined mineralogical and geochemical examinations provided evidence to accept the concept of stepwise generation of different melt phases within the HTCC. The petrogenesis of the melt products may therefore be described as a two-phase melt system with immiscible characteristics that have been successively generated during the melting process of MSW. PMID:18922688

  17. Experimental determination and numerical simulation of viscositites in slag-systems under gasification conditions; Experimentelle Bestimmung und numerische Simulation von Viskositaeten in Schlackesystemen unter Vergasungsbedingungen

    Energy Technology Data Exchange (ETDEWEB)

    Nentwig, Thomas

    2011-07-01

    Silica melts are reflected in many different industrial and natural processes such as slags in steel production and gasification of coal, glass in the glass making industry, lava in the volcanology and in lots of other fields. Rheological properties like the viscosity of this silica melts are really important in all of these processes. A general and good working viscosity model would help all scientists and engineers, who have to simulate and optimise these processes. First, it is important to have the possibility to measure viscosities of slags. As part of this PhD thesis a new high-temperature high-pressure rotational viscosimeter is developed for measurements up to {>=}1600 C and 20 bar. Particularly in relation to the coal gasification process this two parameters are really important, because coal gasification occurs under high temperatures and high pressures. With this new viscosimeter it is possible to measure slag viscosities under realistic gasification conditions. To show that the new viscosimeter works quite good viscosity measurements of four real slags have been done. The influence of pressure and atmosphere on viscosity have been examined. The measurements are also compared with different viscosity models. The Arrhenius- and Weymann-Equation have been determined and the correlation between viscosity and basicity of the slag has been evaluated. In the second part of the Phd thesis a new viscosity model is developed. The model is based on the structure inside the slag and consists in existing thermodynamic models. After a detailed literature research the model is developed for the SiO{sub 2}-Al{sub 2}O{sub 3}-Na{sub 2}O-K{sub 2}O system. The quality of this new model is estimated by comparing calculated viscosity values with measurements found during the literature research. The new model is also compared with other existing models for viscosity calculation.

  18. On the nature of iron-chromium oxides in stainless steel steelmaking slags

    Science.gov (United States)

    Matteazzi, P.; Magrini, M.; Ramous, E.

    1986-02-01

    A number of slags from electric steelmaking production of AISI 420 and AISI 304 steels, were examined by Mössbauer spectroscopy. The slag samples were taken before and after oxygen blowing. The slag constitution showed the presence of a metallic part, MO mixed oxide and Fe-Cr spinel (Fe2+ Fe{x/3+} Cr2-xO4' x<1).

  19. On the nature of iron-chromium oxides in stainless steel steelmaking slags

    International Nuclear Information System (INIS)

    A number of slags from electric steelmaking production of AISI 420 and AISI 304 steels, were examined by Moessbauer spectroscopy. The slag samples were taken before and after oxygen blowing. The slag constitution showed the presence of a metallic part, MO mixed oxide and Fe-Cr spinel. (Auth.)

  20. Effects of slag fineness on durability of mortars

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In recent years, the usages of by-products and wastes in industry have become more important. The importance of the sustainable development is also of increasing. The utilizations of wastes, as mineral admixture or fine aggregate, reduce the consumption of the natural resources and improve the durability of concrete. In this study, the effect of the fineness on the high temperature and sulphate resistances of concrete mortar specimens, produced with ground granulated blast-furnace slag (GBFS)replacing cement, is investigated. The compressive and flexural strength test results for all series related to durability effects,exposing temperature and solutions, exposure times for these durability effects, slag content and fineness are discussed. Consequently, the optimum slag contents are determined for producing the sulphate and high temperature resistant mortars.

  1. High-Temperatures Rheometric Analysis Of Selected Heterogeneous Slag Systems

    Directory of Open Access Journals (Sweden)

    Migas P.

    2015-06-01

    Full Text Available It is known that the dynamic viscosity coefficient of slag – with an increased titanium compounds content in the reducing conditions of the blast furnace - may rapidly change. The products of the reduction reaction, precipitation and separation of titanium compounds are responsible for the thickening effect of the slag and the problems of permeability of blast furnace, causing anomalies in the dipping zone. The presence of solid components (particles in the melts determines the rheological character of the entire system. Identifying the rheological character of semi-solid slag systems provides opportunities for the development of mathematical modeling of liquid phase flows in a dripping zone of the blast furnace, allowing e.g to indentify the unstable parts of a metallurgical aggregate.

  2. Structure and Vibrational Spectra of Slags Produced from Radioactive Waste

    Science.gov (United States)

    Malinina, G. A.; Stefanovsky, S. V.

    2014-05-01

    The structure of the anionic motif of aluminosilicate and aluminoborosilicate glasses containing simulated slags from a solid radioactive waste incinerator was studied by IR and Raman spectroscopy. Spectra of melted slag were consistent with Si-O tetrahedra with various numbers of bridging O ions and Al-O tetrahedra embedded in the Si-O network in the slag vitreous and crystalline phases (nepheline, nagelschmidtite). Vibrations of doubly and triply bound Si-O tetrahedra and Al-O tetrahedra embedded between them were mainly responsible for the spectra as the content of sodium disilicate fl ux and the glass fraction in the materials increased. Addition of sodium tetraborate fl ux caused the appearance of B-O vibrations of predominantly three-coordinate B and a tendency toward chemical differentiation preceding phase separation.

  3. Pb(II) removal from aqueous solution by a low-cost adsorbent dry desulfurization slag

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qiong; You, Ruirong [College of Materials Science and Engineering, Fuzhou University, New Campus, Minhou, Fujian Province 350108 (China); Clark, Malcolm [Marine Ecology Research Centre, School of Environment, Science and Engineering, Southern Cross University, P.O. Box 157, Lismore, NSW 2480 (Australia); Yu, Yan, E-mail: yuyan_1972@126.com [College of Materials Science and Engineering, Fuzhou University, New Campus, Minhou, Fujian Province 350108 (China)

    2014-09-30

    Highlights: • Dry desulfurization slag, solid waste, was an efficient adsorbent for lead removal. • The adsorption of Pb{sup 2+} onto dry desulfurization slag was generally monolayer. • The rate limiting step in the adsorption process of Pb{sup 2+} was chemisorption. • Pb{sup 2+} was absorbed onto the surface of the sample adsorbent only. • The adsorbent was low-cost and could be recycled. - Abstract: A collectable and non-sintered material prepared as hollow cylindrical shaped pellet from dry desulfurization slag (FGD ash) and ordinary Portland cement (OPC) for wastewater treatments is tested. The characteristic results of powder X-ray diffraction (XRD) and infrared absorption spectroscopy (IR) show that –OH, CO{sub 3}{sup 2−}, SO{sub 3}{sup 2−} and SO{sub 4}{sup 2−} are the possible functional groups responsible for Pb uptake. Adsorption data indicate that Pb removal is pH dependent and optimal at pH 6, with a very rapid initial removal that reaches equilibrium in about 90 min. A maximum removal of 99.2% is seen for 5 mg/L (pH of 6); higher initial Pb concentrations reduce overall removal efficiencies, but generate higher surface loadings. Adsorption process correlates well with both Langmuir and Freundlich models, although the Langmuir isotherm is more favored, providing a maximum adsorption capacity (Qm) of 130.2 mg/g (13 wt%). Pseudo-second order rate kinetic model best describes the Pb removal, and calculated R{sub L} values between 0 and 1, indicate a favored adsorption process that is chemisorption limited. SEM and EDAX analysis of the surface and fracture surface show that Pb occurs as surface precipitates and that Pb is not distributed to the inner core of the pellet. This study demonstrates that dry FGD ash could be successfully used for wastewater Pb removal.

  4. Pb(II) removal from aqueous solution by a low-cost adsorbent dry desulfurization slag

    International Nuclear Information System (INIS)

    Highlights: • Dry desulfurization slag, solid waste, was an efficient adsorbent for lead removal. • The adsorption of Pb2+ onto dry desulfurization slag was generally monolayer. • The rate limiting step in the adsorption process of Pb2+ was chemisorption. • Pb2+ was absorbed onto the surface of the sample adsorbent only. • The adsorbent was low-cost and could be recycled. - Abstract: A collectable and non-sintered material prepared as hollow cylindrical shaped pellet from dry desulfurization slag (FGD ash) and ordinary Portland cement (OPC) for wastewater treatments is tested. The characteristic results of powder X-ray diffraction (XRD) and infrared absorption spectroscopy (IR) show that –OH, CO32−, SO32− and SO42− are the possible functional groups responsible for Pb uptake. Adsorption data indicate that Pb removal is pH dependent and optimal at pH 6, with a very rapid initial removal that reaches equilibrium in about 90 min. A maximum removal of 99.2% is seen for 5 mg/L (pH of 6); higher initial Pb concentrations reduce overall removal efficiencies, but generate higher surface loadings. Adsorption process correlates well with both Langmuir and Freundlich models, although the Langmuir isotherm is more favored, providing a maximum adsorption capacity (Qm) of 130.2 mg/g (13 wt%). Pseudo-second order rate kinetic model best describes the Pb removal, and calculated RL values between 0 and 1, indicate a favored adsorption process that is chemisorption limited. SEM and EDAX analysis of the surface and fracture surface show that Pb occurs as surface precipitates and that Pb is not distributed to the inner core of the pellet. This study demonstrates that dry FGD ash could be successfully used for wastewater Pb removal

  5. Archaeo-metallurgical studies of tuyeres and smelting slags found at Tharros (north-western Sardinia, Italy)

    Science.gov (United States)

    de Caro, T.; Riccucci, C.; Parisi, E. I.; Renzulli, A.; Del Moro, S.; Santi, P.; Faraldi, F.

    2013-12-01

    A large number of pyrometallurgical materials such as tuyeres, slags and refractory tools likely associated with metal extraction processes have been found at Tharros (north-western Sardinia, Italy) during archaeological excavations stratigraphically related to the Phoenician-Punic period (VI-III centuries BC). Micro-chemical, micro-structural and mineralogical studies have been carried out by means of the combined use of X-ray diffraction (XRD), selected-area X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) combined with energy-dispersive X-ray analysis (EDS) in order to identify pyrometallurgical processes and main relevant technological parameters. The results reveal that tuyeres, slags and refractory tools can be associated with an iron ore smelting process to extract the metal by slagging the unwanted by-products. Moreover, temperature and duration of the smelting process have been estimated through mineralogical studies and by a comparative analysis between the micro-chemical and structural features of thermally treated refractory materials and tuyeres. The results disclose the high level of technological competence of the ancient metallurgists able to carry out complex high-temperature processes to extract iron from ores by separating the metal from unwanted siliceous species.

  6. Chemical recycling of municipal waste slag by using phase separation

    OpenAIRE

    Nanba, Tokuro; Kuroda, Yutaro; Sakida, Shinichi; Benino, Yasuhiko

    2009-01-01

    A chemical recycling method by using phase separation was applied to municipal waste slags. Glasses were prepared from incineration ash and ash-melted slag, where B(2)O(3) was added to promote phase separation. The glasses were heat-treated at temperatures higher than their glass transition temperatures, and they were soaked in hydrochloric acid, leaching CaO, Fe(2)O(3), K(2)O, and S. Transparent and colorless solids containing ca. 80 mass% of SiO(2) were successfully obtained as residues. It...

  7. Alternative concrete based on alkali-activated slag

    OpenAIRE

    Puertas, F.; Mejía de Gutiérrez, R.; Bernal, S.; Rodríguez, E.

    2008-01-01

    This article reports the results of related to on the performance of concrete made with waterglass (Na2SiO3•nH2O + NaOH)-activated Colombian granulated blast furnace slag. The mechanical strength and durability properties this alkali-activated slag concrete (AAS) were compared to the properties of ordinary Portland cement concrete (OPC) with the same proportion of binder, which ranged from 340 to 512 kg per m3 of concrete. The results indicated that increasing the proportion ...

  8. Accelerated carbonation of steel slags using CO2 diluted sources: CO2 uptakes and energy requirements

    OpenAIRE

    Renato eBaciocchi; Giulia eCosta; Alessandra ePolettini; Raffaella ePomi; Alessio eStramazzo; Daniela eZingaretti

    2016-01-01

    This work presents the results of carbonation experiments performed on Basic Oxygen Furnace (BOF) steel slag samples employing gas mixtures containing 40 and 10% CO2 vol. simulating the gaseous effluents of gasification and combustion processes respectively, as well as 100% CO2 for comparison purposes. Two routes were tested, the slurry phase (L/S=5 l/kg, T=100 °C and Ptot=10 bar) and the thin film (L/S =0.3-0.4 l/kg, T=50 °C and Ptot=7-10 bar) routes. For each one, the CO2 uptake achieved as...

  9. Recycling the insoluble residue from titania slag dissolution (tionite) in clay bricks

    OpenAIRE

    Dondi, Michele; Guarini, Guia; Raimondo, Mariarosa; Zanelli, Chiara; Dalle Fabbriche, Daniele; Agostini, Antonio

    2010-01-01

    Tionite is the insoluble residue from the titania slag dissolution process for TiO2 manufacturing. It is a fine grained sludge consisting of rutile, anatase, amorphous phase and bassanite. Chemical composition is TiO2 (ca. 50%), SiO2 (ca. 30%) and minor Al, Ca, Mg, and Fe, plus residual sulfur, implying an acidic pH of waste. Moisture is about 35% of dry weight. The potential of tionite as colouring agent in clay bricks was appraised by admixing (up to 9%) either as-produced or neutralized ti...

  10. Corrosion of Refractory Alumina-Graphite and Alumina-Graphite-Zirconia in Slag Containing Titania

    Institute of Scientific and Technical Information of China (English)

    XU Yuan; LIU Qing-cai; BAI Chen-guang; CHEN Deng-fu; Joseph W Newkirk

    2004-01-01

    The corrosion of refractory alumina-graphite and alumina-graphite-zirconia in the slag containing titania was studied by immersion tests (quasi-static and dynamic tests). Combining direct observation with microscopic investigations, a mechanism for corrosion was proposed based on the oxidation of graphite and the dissolution of refractory components. During the corrosion process, there are some special phenomena and laws that can be explained by the relation between the corrosion rate and the TiO2 mass percent, the rotational refractory velocity and the morphology of the deteriorated layer.

  11. Mortality patterns of rock and slag mineral wool production workers: an epidemiological and environmental study.

    OpenAIRE

    Robinson, C F; Dement, J M; Ness, G O; Waxweiler, R J

    1982-01-01

    An epidemiological and environmental study of rock and slag mineral wool production workers was undertaken at a plant that has been in operation since the early 1900s. Size characteristics of fibres produced by each process at the plant and data from industrial hygiene surveys were used to evaluate current and past exposures. These data suggest that the average historical airborne fibre concentration probably did not exceed 2.5 fibres/cc before 1935 and 1.0 fibre/cc after 1935. A retrospectiv...

  12. Preliminary assessment of a method utilizing carbon dioxide and steelmaking slags to produce precipitated calcium carbonate

    International Nuclear Information System (INIS)

    Highlights: ► An NH4-salt-based method utilizes CO2 and steelmaking slags to produce pure CaCO3. ► It was determined if its economic potential warrants moving forward. ► Despite small solvent losses, the method was found to have economical potential. ► The method has significant CO2 emissions reduction potential. ► Scaling up the reactor will allow for a more detailed design for the process. -- Abstract: One of the options that can contribute to the reduction of carbon dioxide emissions for climate change mitigation is the so-called CO2 sequestration by mineral carbonation, or CO2 mineral sequestration. Steel manufacturing could benefit from this option by utilizing its own by-products, i.e. steelmaking slags to combine with CO2. We have recently studied a method, where aqueous solution of ammonium salt (e.g. ammonium acetate, ammonium nitrate and ammonium chloride) is used to extract calcium selectively from the steel converter slag, followed by precipitation of pure calcium carbonate by bubbling CO2 through the produced solution. The ammonium salt solution is recovered and re-used. The purpose of this research was to determine if the economic potential of the method warrants moving forward to large-scale application. Despite the small solvent losses, the method was found to have economical potential. In addition, it has significant CO2 emission reduction potential as well. Scaling up the reactor from the small laboratory scale will allow more detailed design for the process to be made followed by a full economical evaluation including all of the important operational and capital investment costs.

  13. Characterization of ancient Indian iron and entrapped slag inclusions using electron, photon and nuclear microprobes

    Indian Academy of Sciences (India)

    P Dillmann; R Balasubramaniam

    2001-06-01

    Compositional and structural information were obtained from an ancient 1600-year old Indian iron using microprobe techniques (EDS, XRD and PIXE). Several different local locations in the iron matrix and in the entrapped slag inclusions were analyzed. The P content of the metallic iron matrix was very heterogeneous. Lower P contents were observed in the regions near slag inclusions. This was correlated to the dephosphorization capacity of the slag. The crystallized phases identified in the slag inclusions were wüstite and fayalite. The compositions of the slag inclusions were relatively homogeneous.

  14. Future Resources for Eco-building Materials: I.Metallurgical Slag

    Institute of Scientific and Technical Information of China (English)

    XU Delong; LI Hui

    2009-01-01

    In order to make an effectivily recycle use of iron and steel slags that are main industrial wastes generated in Chinese metallurgical industry,the current technologies for reprocessing and recycling these wastes into eco-building materials were reviewed,such as preparing cement-steel slag blended cement with steel slag after metal recovery,using the fine powder of blast furnace slag (BFS)for manufacturing slag cement and high performance concrete.A further research on using these available resources more efficiently were discussed.

  15. Distribution behavior of Copper and Tin between FeO-rich slag and iron solution

    Institute of Scientific and Technical Information of China (English)

    李长荣; 洪新; 郑少波; 蒋国昌

    2004-01-01

    The distribution behavior of residual elements copper and tin between FeO-rich slag and iron solution was investigated under the condition of an induction furnace. The results indicate that a part of copper and tin is incidently oxidized when oxygen is blasted into bath to react with iron element. The distribution ratio of copper and tin between slag and metal is about 0.1. Phenomena of Cu and Sn elements segregation and accumulation in slag were observed by means of EPMA analysis. The distribution ratio of copper and tin between slag and metal may descend with increasing of CaO content in slag.

  16. Thermodynamics of Gold Dissolution Behavior in CaO-SiO2-Al2O3-MgOsat Slag System

    Science.gov (United States)

    Han, Yun Soon; Swinbourne, Douglas R.; Park, Joo Hyun

    2015-12-01

    Gold solubility in the CaO-SiO2-Al2O3-MgOsat slag system was measured at 1773 K (1500 °C) under a CO2-CO atmosphere over a wide range of compositions, i.e., 8 to 40 mass pct CaO, 26 to 50 mass pct SiO2, and 0 to 36 mass pct Al2O3, to determine the dissolution mechanism of gold in the CaO-based metallurgical slags. Gold solubility in the present slag system increased with increasing oxygen partial pressure and increasing activity of CaO. From the thermodynamic analysis, the dissolution mechanism of gold into the (alumino-)silicate melts is proposed as follows according to the activity of basic oxide, which indicates that the predominant species of gold is dependent on slag basicity. {Au}(s) + 1/4{O}2 (g) + 1/2( {{O}^{2 - } } ) = ( {{AuO}^{ - } } ),quad ( {a_{BO} 0.1} ) The enthalpy change for the dissolution of gold into the CaO-SiO2-Al2O3-MgOsat slag system was measured to be about -80 kJ/mol, indicating that the gold dissolution is exothermic. From the iso-Au solubility contours, the dominant factor affecting the gold dissolution behavior is the (CaO + MgO)/SiO2 ratio, whereas the influence of Al2O3 was negligible. Consequently, less basic slags and higher processing temperatures, in conjunction with a strongly reducing atmosphere, are recommended to increase gold recovery during pyro-processing of Au-containing e-wastes.

  17. Use of Slag/Sugar Cane Bagasse Ash (SCBA) Blends in the Production of Alkali-Activated Materials

    OpenAIRE

    María V. Borrachero; Jordi Payá; José Monzó; Lourdes Soriano; Mauro M. Tashima; José L.P. Melges; Jorge L. Akasaki; Vinícius N. Castaldelli

    2013-01-01

    Blast furnace slag (BFS)/sugar cane bagasse ash (SCBA) blends were assessed for the production of alkali-activated pastes and mortars. SCBA was collected from a lagoon in which wastes from a sugar cane industry were poured. After previous dry and grinding processes, SCBA was chemically characterized: it had a large percentage of organic matter (ca. 25%). Solutions of sodium hydroxide and sodium silicate were used as activating reagents. Different BFS/SCBA mixtures were studied, replacing part...

  18. In situ observation of the role of alumina particles on the crystallization behavior of slags

    Energy Technology Data Exchange (ETDEWEB)

    Orrling, C.

    2000-09-01

    The confocal laser scanning microscope (CLSM) allows crystallization behavior in liquid slags to he observed in situ at high temperatures. Slags in the lime-silica-alumina-magnesia system are easily tinder cooled and it is possible to construct time temperature transformation (TTT) diagrams for this system. The presence of solid alumina particles its these liquid slags was studied to determine if these particles act as heterogeneous nucleation sites that cause she precipitation of solid material within slags. The introduction of alumina particles reduced the incubation time for the onset of crystallization and increased the temperature at which crystallization was observed in the slags to close to the liquidus temperature for the slag. Crystal growth rates are in a good agreement with Ivantsov's solution of the problem of diffusion controlled dendritic growth. Alumina appears to be a potent nucleating agent in the slag systems that were studied. (author)

  19. Moessbauer, XRD, NAA and XRF study of archaeological slag

    International Nuclear Information System (INIS)

    In 1960, remains of four furnaces from Early Medieval Age were excavated in Nitra. Because a lot of glass-like findings were found on this site the function of furnaces was considered as being used for production of glass even though no analytical tests were performed. These dig-outs were divided into two groups: The first group contains dark glass-like archaeological fragments which were interpreted as a waste (slag) of a glass production. The second group consists of archaeological artefacts which were thought to be a slag from iron production. The main aim of this work is to investigate these two types of archaeological artefacts. Employing standard transmission geometry Moessbauer effect experiments, iron crystallographic sites are identified and compared. In all samples, Fe2+ and Fe3+ structural positions were revealed. In addition, some of the archaeological artefacts that are presumably coming from glass production show traces of metallic iron. On the other hand, slag from iron production exhibit minute contribution of iron oxides in several instances. Additional information about the composition of slag is obtained from X-ray diffraction (XRD), neutron activation analysis (NAA), and X-ray fluorescence (XRF) measurements. (authors)

  20. Dephosphorization of Steelmaking Slag by Leaching with Acidic Aqueous Solution

    Science.gov (United States)

    Qiao, Yong; Diao, Jiang; Liu, Xuan; Li, Xiaosa; Zhang, Tao; Xie, Bing

    2015-12-01

    In the present paper, dephosphorization of steelmaking slag by leaching with acidic aqueous solution composed of citric acid, sodium hydroxide, hydrochloric acid and ion-exchanged water was investigated. The buffer solution of C6H8O7-NaOH-HCl system prevented changes in the pH values. Kinetic parameters including leaching temperature, slag particle size and pH values of the solution were optimized. The results showed that temperature has no obvious effect on the dissolution ratio of phosphorus. However, it has a significant effect on the dissolution ratio of iron. The dephosphorization rate increases with the decrease of slag particle size and the pH value of the solution. Over 90% of the phosphorus can be dissolved in the solution while the corresponding leaching ratio of iron was only 30% below the optimal condition. Leaching kinetics of dephosphorization follow the unreacted shrinking core model with a rate controlled step by the solid diffusion layer, the corresponding apparent activation energy being 1.233 kJ mol-1. A semiempirical kinetic equation was established. After leaching, most of the nC2S-C3P solid solution in the steelmaking slag was selectively dissolved in the aqueous solution and the iron content in the solid residue was correspondingly enriched.

  1. Design and evaluation of a heat recuperator for steel slags

    International Nuclear Information System (INIS)

    New techniques for emissions reduction and energy efficiency are important challenges of the steel industry. Although great advantages have been reached in these fields, there are still new opportunities. One of them is the possible development of systems to recover energy from slags. The recent policies that encourage the use of renewable and alternative energies determine a favorable scenario for the development of new techniques of heat recovering. In this context, this article presents a new heat recuperation system for the slags produced in the factories of Arcelor–Mittal in Asturias (Spain) and study in detail the design of an innovative slags heat exchanger. To adjust its performance and to determine the influence of the geometric and flow design parameters, the heat exchanger has been simulated using numerical analysis software (CFD). -- Highlights: • A new design of a heat recuperator for slags energy recovery is presented. • The effects of the design parameters have been studied with a numerical model. • Refractory materials with high thermal conductivity improve heat recuperation

  2. Kinetics of Aqueous Leaching and Carbonization of Steelmaking Slag

    Science.gov (United States)

    Lekakh, S. N.; Rawlins, C. H.; Robertson, D. G. C.; Richards, V. L.; Peaslee, K. D.

    2008-02-01

    Sequestration of carbon dioxide by steelmaking slag was studied in an atmospheric three-phase system containing industrial slag particles, water, and CO2 gas. Batch-type reactors were used to measure the rate of aqueous alkaline leaching and slag particle carbonization independently. Four sizes of slag particles were tested for the Ca leaching rate in deionized water at a constant 7.5 pH in an argon atmosphere and for carbonate conversion with CO2 bubbled through an aqueous suspension. Conversion data (fraction of Ca leached or converted to carbonate) were evaluated to determine the rate-limiting step based on the shrinking core model. For Ca leaching, the chemical reaction is the controlling mechanism during the initial period of time, which then switches to diffusion through the developed porous layer as the rate-limiting step. Carbonate conversion proceeded much slower than leaching conversion and was found to be limited by diffusion through the product calcium carbonate layer. The calculated value of diffusivity was found to be 5 × 10-9 cm2/s, which decreased by an order of magnitude with increasing carbonization conversion as a result of changing density of the product layer. The experimental data fit the shrinking core model well after correction for the particle specific surface area.

  3. Application of aluminum slag incorporated in lightweigh aggregate

    International Nuclear Information System (INIS)

    The use of industrial waste materials as additives in the manufacture of ceramic product has been attracting a growing interest in the last few years and is becoming common practice. The main purpose of this work is to evaluate the possibility of incorporation of aluminum slag into clay materials. Expansive clays are obtained from a pyro plastic expansion, and are usually employed like lightweight aggregate in structural concrete as ornamental garden products. The characterization of the aluminum slag and clay materials was carried out by Xray fluorescence spectrometry, Xray diffraction, granulometry, differential thermal analysis, thermal gravimetry (DTA and TG) and scanning electron microscopy. The studied compositions contained 5, 10, 15 and 20 weight % of aluminum slag into clay mass. The linear expansion, mass variation, apparent specific mass and water absorption of all compositions were determined. Leaching and solubilization experiments were also performed. The main results show the viability of using up to 5 wt% aluminum slag for producing expansive clays with characteristics within the accepted standards. (author)

  4. Accelerated carbonation of steelmaking slags in a high-gravity rotating packed bed

    International Nuclear Information System (INIS)

    Highlights: ► The carbonation conversion in a RPB was higher than that in traditional reactors. ► The optimum conditions were operated at 750 rpm and 65 °C for 30 min. ► The product on BOF slag was identified as crystallized calcite based on SEM and XRD. ► The diffusivity ranged from 10−7 to 10−6 cm2 s−1 based on the shrinking core model. - Abstract: Carbon dioxide (CO2) sequestration using the accelerated carbonation of basic oxygen furnace (BOF) slag in a high-gravity rotating packed bed (RPB) under various operational conditions was investigated. The effects of reaction time, reaction temperature, rotation speed and slurry flow rate on the CO2 sequestration process were evaluated. The samples of reacted slurry were analyzed quantitatively using thermogravimetric analysis (TGA) and atomic absorption spectrometry (AAS) and qualitatively using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and transmission electron microscopy (TEM). The sequestration experiments were performed at a liquid-to-solid ratio of 20:1 with a flow rate of 2.5 L min−1 of a pure CO2 stream under atmospheric temperature and pressure. The results show that a maximum conversion of BOF slag was 93.5% at a reaction time of 30 min and a rotation speed of 750 rpm at 65 °C. The experimental data were utilized to determine the rate-limiting mechanism based on the shrinking core model (SCM), which was validated by the observations of SEM and TEM. Accelerated carbonation in a RPB was confirmed to be a viable method due to its higher mass-transfer rate.

  5. Cold experiments on ligament formation for blast furnace slag granulation

    International Nuclear Information System (INIS)

    Rotary cup atomization for molten slag granulation is an attractive alternative to water quenching. However, the mechanism of disintegration of molten slag must be assessed. In the present study, a glycerol/water mixture was substituted for molten slag, and the mechanism of ligament formation in a rotary cup was investigated using photos taken by a high-speed camera. The effects of the angular speed and inner depth of the rotary cup on ligament disintegration was investigated. The results showed that one state of disintegration may transform into another state as the angular speed of the rotary cup increases at a given liquid flow rate. During ligament formation, the number of ligaments increased with an increase in the angular speed of the rotary cup, and a decrease in the diameter of ligament and liquid drop was observed. Moreover, the initial point of disintegration of the ligament moved to the lip of the rotary cup as the angular speed increased. An equation describing the relationship between the diameter of the liquid drop and various factors was used to predict the diameter of the liquid drop. A rotary cup with an inner depth of 30 mm was the best choice for granulation. The results of the present study will be useful for designing devices used in molten slag granulation. - Highlights: ►The results can be used in the granulation of molten blast furnace slag. ► The three different states of disintegration occur as the angular speed of rotary cup increases. ► The mechanism of ligament disintegration is analyzed. ► Eq. can be used to predict the diameter of liquid drop. ► A rotary cup with an inner depth of 30 mm is optimal for granulation.

  6. Analysis of slags using laser-induced breakdown spectroscopy

    Science.gov (United States)

    Sanghapi, Hervé K.; Ayyalasomayajula, Krishna K.; Yueh, Fang Y.; Singh, Jagdish P.; McIntyre, Dustin L.; Jain, Jinesh C.; Nakano, Jinichiro

    2016-01-01

    The feasibility of laser-induced breakdown spectroscopy (LIBS) for the analysis of gasification slags was investigated by comparing LIBS results to the results of an ICP-OES analyzer. A small amount of slag sample was placed on a piece of double sided adhesive tape attached to a glass microscope slide and analyzed for Al, Ca, Fe, Si, and V which are major elements found in slags. The partial least squares regression (PLS-R) and univariate simple linear regression (SLR) calibration methods indicated that apart from V (accuracy up to + 20%) the accuracy of analysis varies within 0.35-6.5% for SLR and 0.06-10% for PLS-R. A paired-sample t-test within the 95% confidence level yielded p-values greater than 0.05, meaning no appreciable statistical difference was observed between the univariate SLR with internal standardization and the multivariate PLS-R for most of the analytes. From the results obtained in this work, LIBS response varies depending on the element and the technique used for quantitative analysis. Simultaneous use of the univariate calibration curves with internal standard (intensity ratio) and PLS regression in multi-elemental analysis can help reduce the matrix effect of slags associated to their high variation in concentration. Overall, these results demonstrate the capability of LIBS as an alternative technique for analyzing gasification slags. Estimated limits of detection for Al, Ca, Fe, Si and V were 0.167, 0.78, 0.171, 0.243 and 0.01 wt.%, respectively.

  7. Disintegration and size reduction of slags and metals after melt refining of contaminated metallic wastes

    International Nuclear Information System (INIS)

    Melting under an oxidizing slag is an attractive method of decontaminating and reducing the volume of radioactively contaminated metal scrap. The contaminants are concentrated in a relatively small volume of slag, which leaves the metal essentially clean. A potential method of permanently disposing of the resulting slags (and metals if necessary) is emplacing them into deep shale by grout hydrofracture. Suspension in grout mixtures requires that the slag and metal be granular. The feasibility of size-reducing slags and disintegrating metals and subsequently incorporating both into grout mixtures was demonstrated. Various types of slags were crushed with a small jaw crusher into particles smaller than 3 mm. Several metals were also melted and water-blasted into coarse metal powder or shot ranging in size from 0.05 to 3 mm. A simple low-pressure water atomizer having a multiple nozzle with a converging-line jet stream was developed and used for this purpose. No significant slag dust and steam were generated during slag crushing and liquid-metal water-blasting tests, indicating that contamination can be well contained within the system. The crushed slags and the coarse metal powders were suspendable in group fluids, which indicates probable disposability by shale hydrofracture. The granulation of slags and metals facilitates their containment, transport, and storage

  8. Steel slag filters to upgrade phosphorus removal in constructed wetlands: two years of field experiments.

    Science.gov (United States)

    Barca, Cristian; Troesch, Stéphane; Meyer, Daniel; Drissen, Peter; Andrès, Yves; Chazarenc, Florent

    2013-01-01

    Electric arc furnace steel slag (EAF-slag) and basic oxygen furnace steel slag (BOF-slag) were used as filter substrates in two horizontal subsurface flow filters (6 m(3) each) designed to remove phosphorus (P) from the effluent of a constructed wetland. The influences of slag composition, void hydraulic retention time (HRTv), temperature, and wastewater quality on treatment performances were studied. Over a period of almost two years of operation, the filter filled with EAF-slag removed 37% of the inlet total P, whereas the filter filled with BOF-slag removed 62% of the inlet total P. P removal occurred predominantly via CaO-slag dissolution followed by Ca phosphate precipitation. P removal efficiencies improved with increasing temperature and HRTv, most probably because this affected the rates of CaO-slag dissolution and Ca phosphate precipitation. It was observed that long HRTv (>3 days) can cause high pH in the effluents (>9) as a result of excessive CaO-slag dissolution. However, at shorter HRTv (1-2 days), pH values were elevated only during the first five weeks and then stabilized below a pH of 9. The kinetics of P removal were investigated employing a first-order equation, and a model for filter design was proposed. PMID:23198779

  9. 木薯渣发酵饲料的工艺筛选%Screening of technology in cassava slag fermentation feed

    Institute of Scientific and Technical Information of China (English)

    艾必燕; 刘长忠; 陈建康; 杨扬; 米本中; 黄倩妮; 樵星芳

    2012-01-01

    Using cassava slag as the main raw material, with aspergillus, trichoderma viride and rhizopus R2 for fermentation strains, the test is to optimize cassava slag fermentation technology producing tropina feed. The appropriate conditions of cassava slag fermentation are that adding amount of liquid spawn is 3%, adding amount of nitrogen source is 10%, fermentation temperature is 37 ℃, fermentation time is 4 days. Cassava slag is a mixture, its highest level of non-nitrogen compounds is 78.7%, main component is soluble starch compounds (such as monosaccharide and starch), but its crude protein content is very low, amino acid composition is extremely uneven, it has poor effect to feed cassava slag directly, so most of the cassava slag cannot be used, which not only causes the waste of resources, but also seriously pollutes environment. Processing cassava slag into feed materials can make full use of the waste in starch industry, it is favorable to the environment protection, and it also can significantly reduce the cost of feed, improve the utilization value and economic benefits of cassava slag.%以木薯生产中产生的废渣为主要原料,以黑曲霉、绿色木霉和根霉R2为发酵菌种,优化木薯渣发酵生产菌体蛋白饲料的工艺.初步确定了木薯渣发酵的适宜条件,即液体菌种添加量为3%,氮源添加量为20%,发酵温度37℃,发酵时间为4d,经试验验证,此发酵条件下发酵饲料中粗蛋白含量较高,可达到蛋白饲料对蛋白质含量的要求.通过处理木薯渣变为动物的饲料原料,不仅可充分利用淀粉工业的废弃物,有利于环境保护,而且可显著降低饲养成本,从而提高了木薯渣的利用价值和经济效益.

  10. Hydraulic activity of cement mixed with slag from vitrified solid waste incinerator fly ash.

    Science.gov (United States)

    Lin, Kae-Long; Wang, Kuen-Sheng; Tzeng, Bor-Yu; Lin, Chung-Yei

    2003-12-01

    This study investigates the effects of the slag composition on the hydraulic activity in slag blended cement pastes that incorporate synthetic slag prepared by melting CaO-modified municipal solid waste incinerator fly ash. Two types of composition-modified slag were prepared for this study. First, fly ash was mixed with the modifier (CaO) at 5% and 15% (by weight) respectively, resulting in two fly ash mixtures. These mixtures were then melted at 1400 degrees C for 30 minutes and milled to produce two types of slag with different modifier contents, designated as C1-slag and C2-slag. These synthetic slags were blended with ordinary Portland cement at various weight ratios ranging from 10% to 40%. The synthetic slags presented sufficient hydraulic activity, and the heavy metal leaching concentrations all met the EPA's regulatory thresholds. The pore size distribution was determined by mercury intrusion porosimetry, and the results correlated with the compressive strength. The results also indicate that the incorporation of the 10% C1-slag tended to enhance the hydration degree of slag blended cement pastes during the early ages (3-28 days). However, at later ages, no significant difference in hydration degree was observed between ordinary Portland cement pastes and 10% C1-slag blended cement pastes. In the 10% C2-slag case, the trend was similar, but with a more limited enhancement during the early ages (3-28 days). Thus vitrified waste incinerator fly ash is a technically useful additive to cement, reducing the disposal needs for the toxic fly ash. PMID:14986718

  11. Utilization of ferrochrome wastes such as ferrochrome ash and ferrochrome slag in concrete manufacturing.

    Science.gov (United States)

    Acharya, Prasanna K; Patro, Sanjaya K

    2016-08-01

    Solid waste management is one of the subjects essentially addressing the current interest today. Due to the scarcity of land filling area, utilization of wastes in the construction sector has become an attractive proposition for disposal. Ferrochrome ash (FA) is a dust obtained as a waste material from the gas cleaning plant of Ferro alloy industries. It possesses the chemical requirements of granulated slag material used for the manufacture of Portland cement. Ferrochrome slag (FS) is another residue that is obtained as a solid waste by the smelting process during the production of stainless steel in Ferroalloy industries. FS possesses the required engineering properties of coarse aggregates. The possibility of using FA with lime for partial replacement of ordinary Portland cement (OPC) and FS for total replacement of natural coarse aggregates is explored in this research. The combined effect of FA with lime and FS-addition on the properties of concrete, such as workability, compressive strength, flexural strength, splitting tensile strength and sorptivity, were studied. Results of investigation revealed improvement in strength and durability properties of concrete on inclusion of FA and FS. Concrete mix containing 40% FA with 7% lime (replacing 47% OPC) and100% of FS (replacing 100% natural coarse aggregate) achieved the properties of normal concrete or even better properties at all ages. The results were confirmed by microscopic study such as X-ray diffraction and petrography examination. Environmental compatibility of concrete containing FA and FS was verified by the toxicity characteristic leaching procedure test. PMID:27357563

  12. Two-stage high temperature sludge gasification using the waste heat from hot blast furnace slags.

    Science.gov (United States)

    Sun, Yongqi; Zhang, Zuotai; Liu, Lili; Wang, Xidong

    2015-12-01

    Nowadays, disposal of sewage sludge from wastewater treatment plants and recovery of waste heat from steel industry, become two important environmental issues and to integrate these two problems, a two-stage high temperature sludge gasification approach was investigated using the waste heat in hot slags herein. The whole process was divided into two stages, i.e., the low temperature sludge pyrolysis at ⩽ 900°C in argon agent and the high temperature char gasification at ⩾ 900°C in CO2 agent, during which the heat required was supplied by hot slags in different temperature ranges. Both the thermodynamic and kinetic mechanisms were identified and it was indicated that an Avrami-Erofeev model could best interpret the stage of char gasification. Furthermore, a schematic concept of this strategy was portrayed, based on which the potential CO yield and CO2 emission reduction achieved in China could be ∼1.92∗10(9)m(3) and 1.93∗10(6)t, respectively. PMID:26409106

  13. Accelerated carbonation of steelmaking slags in a high-gravity rotating packed bed.

    Science.gov (United States)

    Chang, E-E; Pan, Shu-Yuan; Chen, Yi-Hung; Tan, Chung-Sung; Chiang, Pen-Chi

    2012-08-15

    Carbon dioxide (CO(2)) sequestration using the accelerated carbonation of basic oxygen furnace (BOF) slag in a high-gravity rotating packed bed (RPB) under various operational conditions was investigated. The effects of reaction time, reaction temperature, rotation speed and slurry flow rate on the CO(2) sequestration process were evaluated. The samples of reacted slurry were analyzed quantitatively using thermogravimetric analysis (TGA) and atomic absorption spectrometry (AAS) and qualitatively using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and transmission electron microscopy (TEM). The sequestration experiments were performed at a liquid-to-solid ratio of 20:1 with a flow rate of 2.5 L min(-1) of a pure CO(2) stream under atmospheric temperature and pressure. The results show that a maximum conversion of BOF slag was 93.5% at a reaction time of 30 min and a rotation speed of 750 rpm at 65°C. The experimental data were utilized to determine the rate-limiting mechanism based on the shrinking core model (SCM), which was validated by the observations of SEM and TEM. Accelerated carbonation in a RPB was confirmed to be a viable method due to its higher mass-transfer rate. PMID:22633879

  14. Influence of Silica on the Lime-Free Roasting of Chromium-Containing Slag

    Science.gov (United States)

    Yu, Kai-ping; Chen, Bo; Zhang, Hong-ling; Liu, Yuan-yue; Duan, Shao-yong; Xu, Hong-bin; Zhang, Yi

    2016-02-01

    The evolution of silica during the lime-free roasting and their roles were investigated using chromium-containing slag with high content of ferric oxide and silica. The siliceous salt phases were analyzed by means of X-ray diffraction, scanning electron microscope, and energy-dispersive X-ray spectroscopy. The reaction rule involved with silicon-containing compounds in the roasting process was also discussed. The results showed that both oxidation of Cr2O3 and leaching of Na2CrO4 were influenced by the siliceous salts. It suggested that roasting temperature and the amount of alkali act as important factors for the phase transformation of silicon. NaFe(SiO3)2 was formed in the temperature which is best for the production of Na2CrO4, while excess amount of alkali could decompose acmite into NaFeO2 and Na2SiO3. It was observed that a large amount of insoluble NaFe(SiO3)2 took shape during the lime-free roasting when the temperature was above 1273 K (1000 °C). The extracting rate of chromium from chromium-containing slag roasted at 1373 K (1100 °C) was only 29.99 pct and almost no silicon was leached out.

  15. Resistance of Alkali-Activated Slag Concrete to Chloride-Induced Corrosion

    Directory of Open Access Journals (Sweden)

    Joon Woo Park

    2015-01-01

    Full Text Available The corrosion resistance of steel in alkali-activated slag (AAS mortar was evaluated by a monitoring of the galvanic current and half-cell potential with time against a chloride-contaminated environment. For chloride transport, rapid chloride penetration test was performed, and chloride binding capacity of AAS was evaluated at a given chloride. The mortar/paste specimens were manufactured with ground granulated blast-furnace slag, instead of Portland cement, and alkali activators were added in mixing water, including Ca(OH2, KOH and NaOH, to activate hydration process. As a result, it was found that the corrosion behavior was strongly dependent on the type of alkali activator: the AAS containing the Ca(OH2 activator was the most passive in monitoring of the galvanic corrosion and half-cell potential, while KOH, and NaOH activators indicated a similar level of corrosion to Portland cement mortar (control. Despite a lower binding of chloride ions in the paste, the AAS had quite a higher resistance to chloride transport in rapid chloride penetration, presumably due to the lower level of capillary pores, which was ensured by the pore distribution of AAS mortar in mercury intrusion porosimetry.

  16. Kinetics of the leaching of TiO2 from Ti-bearing blast furnace slag

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-hua; GAI Guo-sheng; YANG Yu-fen; SUI Zhi-tong; LI Li; FU Jian-xia

    2008-01-01

    Ti-bearing blast furnace slag is a valuable secondary resource containing about 24 percent of TiO2. In this paper a process of leaching Ti-bearing blast furnace slag with sulfuric acid to recover TiO2, and the kinetics of that reaction, are described. Under laboratory conditions the rate is controlled by a chemical reaction. The leaching reaction is in accord with a shrinking un-reacted-core model. The apparent reaction order of the leaching reaction was 1.222 and the apparent activation energy was 87.01 kJ/mol. The model fits the observed data well until 90% of the TiO2 has be leached from the particles. The model disagrees with observations during later periods of the reaction because the solution becomes supersaturated with Ti ions, which precipitate as H2TiO4. The assumptions of constant reactant concentration and that there is no effect from the product layer on diffusion, also cause the model to deviate from the actual values.

  17. Immobilisation of lead smelting slag within spent aluminate-fly ash based geopolymers.

    Science.gov (United States)

    Ogundiran, M B; Nugteren, H W; Witkamp, G J

    2013-03-15

    This study presents the solidification/stabilisation and immobilisation of lead smelting slag (LSS) by its incorporation in coal fly ash - blast furnace slag based geopolymers. It also explores the use of a spent aluminium etching solution (AES) as geopolymer activator instead of the commonly used silicate solutions. The compressive strength of the geopolymers produced with the AES was lower than when applying a K-silicate solution as activator (100MPa versus 80MPa after 28 days). Compressive strength was not affected when up to 10% of the FA was replaced by LSS. NEN 12457-4, TCLP, SPLP and NEN 7375 leaching tests indicated that mobile Pb from LSS was highly immobilised. The diffusion leaching test NEN 7375 revealed exceeding of the Dutch Soil Quality Regulation threshold limits only for Se and Sb. On the condition that the remaining excess leaching can be reduced by further refinement of the mixture recipes, the proposed process will have the potential of producing waste-based construction materials that may be applied under controlled conditions in specific situations. PMID:23339881

  18. Decomposition Kinetics of Titania Slag in Eutectic NaOH-NaNO3 System

    Science.gov (United States)

    Wang, Dong; Wang, Zhi; Qi, Tao; Wang, Lina; Xue, Tianyan

    2016-02-01

    The decomposition kinetics and mechanism of titania slag in eutectic NaOH-NaNO3 system were studied in the temperature range 623 K to 723 K (350 °C to 450 °C). Decomposed products were examined using X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy. It has been identified that the main product is Na2TiO3 and the decomposition kinetics of titania slag followed a shrinking unreacted core model. It is proposed that the chemical reaction process was the rate determining step with apparent activation energy of 62.4 kJ/mol. NaNO3 was mainly acted as oxygen carrier and mass transport agent to lower the viscosity of the system. The purity of TiO2 obtained in the product was up to 99.3 pct. A flow diagram to produce TiO2 and to recycle the media was proposed.

  19. Performance of water quenched slag particles (WQSP) for municipal wastewater treatment in a biological aerated filter (BAF)

    International Nuclear Information System (INIS)

    Water quenched slag particles (WQSP) and haydite were applied to treat municipal wastewater in two lab-scale up-flow biological aerated filters (BAF) to compare their abilities to act as biofilm supports. The results showed that WQSP reactor brought a relative superiority to haydite reactor in terms of chemical oxygen demand (CODcr) and ammonia nitrogen (NH3-N) removal when hydraulic retention time (HRT) ranged from 1 h to 5 h.Compared with haydite, WQSP had higher total porosity, larger total surface area and lower bulk and apparent density. Tests of heavy metal elements in lixivium proved that WQSP were safe for wastewater treatment. In addition, the detection of the amount of hetero bacteria and nitrobacteria of two biological aerated filters in three HRTs also showed that WQSP medium was more suitable to the attached growth of nitrobacteria, which is helpful to the improvement of nitrification performance in WQSP BAF. Therefore, WQSP is a potential material for use as the filter media of BAF for wastewater treatment. WQSP application, as a novel process of treating wastes with waste, provides a promising way to use water quenched slag (WQS). -- Highlights: ► Novel filter media-water quenched slag particles (WQSP) were prepared. ► Two upflow BAFs were applied to treat municipal wastewater. ► WQSP reactor brought a relative superiority to haydite reactor. ► WQSP medium was more suitable to the attached growth of nitrobacteria. ► The application provided a promising way in water quenched slag waste material utilization.

  20. Velocity and temperature distributions of coal-slag layers on magnetohydrodynamic generators walls

    Science.gov (United States)

    Pian, C. C. P.; Smith, J. M.

    1977-01-01

    Approximate analytical expressions are derived for the velocity and temperature distributions in steady state coal slag deposits flowing over MHD generator walls. Effects of slag condensation and Joule heating are included in the analysis. The transport conditions and the slag temperature at the slag-gas interface are taken to be known parameters in the formulation. They are assumed to have been predetermined either experimentally or from the slag properties and the gas dynamic calculations of the free stream flow. The analysis assumes a power law velocity profile for the slag and accounts for the coupling between the energy and momentum conservation equations. Comparisons are made with the more exact numerical solutions to verify the accuracy of the results.

  1. Theoretical analysis of the interfacial phenomena during the injection of carbon particles into EAF slags

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, H.H.; Morales, R.D. [Instituto Politecnico Nacional, Mexico City (Mexico). Dept. of Metallurgy and Materials Engineering; Conejo, A.N. [Inst. Tecnologico de Morelia (Mexico)

    2001-08-01

    A theoretical analysis of FeO reduction through the injection of carbon fines in electric arc furnace slags, involving the interfacial phenomena at the liquid-gas-solid interface, has been performed using basic principles of transport phenomena and physical chemistry of steelmaking. It was found that small angle contacts between slag and carbon favour FeO reduction. Moreover, FeO in basic slags are more prone to be reduced because the interfacial liquid-gas interface has more free reaction places. In acid slags FeO reduction is difficult because the gas-liquid interface is partially filled by polymeric silicates. When the particle size is smaller than 100 {mu}m the influence of slag basicity is considerably decreased. Practical applications of these results can be found in electric arc furnace shops aiming at the mastering of slag foaming practices and energy saving. (orig.)

  2. Sintering behavior of flying slag particles in entrained-bed coal gasifiers. 3rd Report. Effect of soot on sintering behavior of flying slag particles; Kiryuso sekitan gas ka ro ni okeru hisan slag fun no shoketsu tokusei. 3. Char chu tansobun no slag shoketsu yokusei sayo

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, A.; Kida, E. [Babcock Hitachi K.K., Tokyo (Japan)

    1997-05-25

    The effect of char addition on sintering behavior of flying slag particles in an entrained-bed coal gasifier was examined using four kinds of amorphous water-quenched slag obtained at the pilot plant of HYCOL. This plant was designed to gasify 50 tons of coal per day. The sintering temperatures of the four slags without char were all approximately 800{degree}C. However, Taiheiyo coal slag did not sinter at 900{degree}C when the char added. It was considered that the char collected by the cyclon was a mixture of soot and unburned coal particles and the soot prevented the slag from sintering. Therefore, the effect of soot on sintering behavior was clarified using carbon black as soot. SEM and EDX analyses showed that very small soot particles acted as a dispersant in the slag. 12 refs., 13 figs., 2 tabs.

  3. PRECIPITATION AND GROWTH OF PEROVSKITE PHASE IN TITANIUM BEARING BLAST FURNACE SLAG

    Institute of Scientific and Technical Information of China (English)

    Z.Z. Guo; T.P. Lou; L. Zhang; L.N. Zhang; Z.T. Sui

    2007-01-01

    The effects of transformation of slag composition and additive agents on the morphology, the crystal in the Ti-bearing blast furnace slags were investigated. As the morphology of perovskite is dispersed in molten slags, the crystal growth mechanism of the melting of fine dendrites and the coarsening of large grains exist throughout the solidification of molten slags. With the increase of CaO and Fe2O3 content, VF of perovskite obviously increases. However, high basicity leads to the viscosity of slag, which results in the reduction of the average equivalent diameter (AED). The experimental results showed that the presence of the additives CaF2 and MnO efficiently decreased the viscosity of the slags, and obviously improved the morphology of perovskite and promoted its growth.

  4. Applicability of law of mass action to distribution of manganese between slag melts and liquid iron

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    According to the law of mass action and the coexistence theory of slag structure, the distribution of man ganese between MnO-FeO-SiO2 and MgO-MnO-FeO-SiO2 slag melts as well as liquid iron was analyzed. It is shown that K ′Mn and K Mno are only dependent on temperature and don' t change with basicities and compositions of slag melts. So the distribution of manganese between the above mentioned slag melts and molten iron obeys the law of mass action. But anal ysis of experimental results from other sources shows that K′Mn and K Mno really change with basicities of slag, which is probably arisen from not approaching equilibrium under low basicity slag melts.

  5. X-ray diffractometry of steam cured ordinary Portland and blast-furnace-slag cements

    International Nuclear Information System (INIS)

    This work studies some aspects of the phases produced by hydration of ordinary and blast-furnace-slag cements, at normal conditions and steam cured (60 and 950 C), using an X-ray diffraction technique. The blast-furnace-slag cement was a mixture of 50% of ordinary Portland cement and 50% of blast-furnace-slag (separately grinding). After curing the X-ray diffraction reveals that, in relation to ordinary Portland cement, the main phases in blast-furnace-slag cement are hydrated silicates and aluminates, hydro garnet, etringitte and mono sulphate. After steam curing the hydration of blast-furnace-slag cement proceeds. This is a result of the slag activation by the curing temperature. (author). 8 refs., 3 figs., 1 tab

  6. Evaluation of candidate boiler coal slags for hydrogen sulfide removal from producer gas

    International Nuclear Information System (INIS)

    Six type of coal slags were tested for H2S retention in a TGA reactor under conditions simulating modern coal gasifiers (850 - 1000 deg. and 0.7-1.1 vol % H2S). Results based on analysis from XRD and SEM/EDS showed that the iron contained in the slag was responsible for the removal of H2S in the form of Fes1.1. The reactivity of slag for H2S removal achieved at 850 deg. and 1.1% H2S varied between 7 and 30%. This was found to increase with increasing iron content in slag. Slag reactivity with H2S could be enhanced by decreasing the slag particle size and/ or raising the sulfidation reaction temperature. (author).20 refs., 5 figs. 2 tabs

  7. Composite cements containing natural pozzolan and granulated blast furnace slag

    OpenAIRE

    Irassar, E. F.; Rahhal, V.F.; Donza, H. A.; Menéndez, G.; Bonavetti, V. L.

    2006-01-01

    For reasons of market demand and Portland cement production,the manufacture of cements with two or more separately ground additions to produce customized cements is becoming common practice.When pozzolan or slag content in this type of cements is high, however, the initial strength of the resulting product may be adversely impacted. This problem can be minimized by activating one or both of the replacement materials. The present study analyzes the effect of Portland cement additions such as p...

  8. Low-Chrome/Chrome Free Refractories for Slagging Gasifiers

    International Nuclear Information System (INIS)

    Gasifiers are containment vessels used to react carbon-containing materials with oxygen and water, producing syngas (CO and H2) that is used in chemical and power production. It is also a potential source of H2 in a future hydrogen economy. Air cooled slagging gasifiers are one type of gasifier, operating at temperatures from 1275-1575 C and at pressures of 400 psi or higher. They typically use coal or petroleum coke as the carbon source, materials which contain ash impurities that liquefy at the gasification temperatures, producing liquid slag in quantities of 100 or more tons/day, depending on the carbon fed rate and the percent ash present in the feedstock. The molten slag is corrosive to refractory linings, causing chemical dissolution and spalling. The refractory lining is composed of chrome oxide, alumina, and zirconia; and is replaced every 3-24 months. Gasifier users would like greater on-line availability and reliability of gasifier liners, something that has impacted gasifier acceptance by industry. Research is underway at NETL to improve refractory service life and to develop a no-chrome or low-chrome oxide alternative refractory liner. Over 250 samples of no- or low-chrome oxide compositions have been evaluated for slag interactions by cup testing; with potential candidates for further studies including those with ZrO2, Al2O3, and MgO materials. The development of improved liner materials is necessary if technologies such as IGCC and DOE's Near Zero Emissions Advanced Fossil Fuel Power Plant are to be successful and move forward in the marketplace

  9. Heat Recovery from High Temperature Slags: A Review of Chemical Methods

    OpenAIRE

    Yongqi Sun; Zuotai Zhang; Lili Liu; Xidong Wang

    2015-01-01

    Waste heat recovery from high temperature slags represents the latest potential way to remarkably reduce the energy consumption and CO2 emissions of the steel industry. The molten slags, in the temperature range of 1723–1923 K, carry large amounts of high quality energy. However, the heat recovery from slags faces several fundamental challenges, including their low thermal conductivity, inside crystallization, and discontinuous availability. During past decades, various chemical methods have ...

  10. Short review on the origin and countermeasure of biomass slagging in grate furnace

    OpenAIRE

    Yiming eZhu; Yanqing eNiu; Houzhang eTan; Xuebin eWang

    2014-01-01

    Given the increasing demand for energy consumption, biomass has been more and more important as a new type of clean renewable energy source. Biomass direct firing is the most mature and promising utilization method to date, while it allows a timely solution to slagging problems. Alkali metal elements in the biomass fuel and the ash fusion behavior, as the two major origins contributing to slagging during biomass combustion, are analyzed in this paper. The slag presents various layered structu...

  11. Effects of slag-based silicon fertilizer on rice growth and brown-spot resistance.

    Science.gov (United States)

    Ning, Dongfeng; Song, Alin; Fan, Fenliang; Li, Zhaojun; Liang, Yongchao

    2014-01-01

    It is well documented that slag-based silicon fertilizers have beneficial effects on the growth and disease resistance of rice. However, their effects vary greatly with sources of slag and are closely related to availability of silicon (Si) in these materials. To date, few researches have been done to compare the differences in plant performance and disease resistance between different slag-based silicon fertilizers applied at the same rate of plant-available Si. In the present study both steel and iron slags were chosen to investigate their effects on rice growth and disease resistance under greenhouse conditions. Both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to examine the effects of slags on ultrastructural changes in leaves of rice naturally infected by Bipolaris oryaze, the causal agent of brown spot. The results showed that both slag-based Si fertilizers tested significantly increased rice growth and yield, but decreased brown spot incidence, with steel slag showing a stronger effect than iron slag. The results of SEM analysis showed that application of slags led to more pronounced cell silicification in rice leaves, more silica cells, and more pronounced and larger papilla as well. The results of TEM analysis showed that mesophyll cells of slag-untreated rice leaf were disorganized, with colonization of the fungus (Bipolaris oryzae), including chloroplast degradation and cell wall alterations. The application of slag maintained mesophyll cells relatively intact and increased the thickness of silicon layer. It can be concluded that applying slag-based fertilizer to Si-deficient paddy soil is necessary for improving both rice productivity and brown spot resistance. The immobile silicon deposited in host cell walls and papillae sites is the first physical barrier for fungal penetration, while the soluble Si in the cytoplasm enhances physiological or induced resistance to fungal colonization. PMID:25036893

  12. A Microstructure Based Strength Model for Slag Blended Concrete with Various Curing Temperatures

    OpenAIRE

    Li-Na Zhang; Wang Xiao-Yong; Kyung-Taek Koh

    2016-01-01

    Ground granulated blast furnace slag, which is a byproduct obtained during steel manufacture, has been widely used for concrete structures in order to reduce carbon dioxide emissions and improve durability. This paper presents a numerical model to evaluate compressive strength development of slag blended concrete at isothermal curing temperatures and time varying curing temperatures. First, the numerical model starts with a cement-slag blended hydration model which simulates both cement hydra...

  13. Abatement of Chromium Emissions from Steelmaking Slags - Cr Stabilization by Phase Separation

    OpenAIRE

    Albertsson, Galina

    2013-01-01

    Chromium is an important alloying element in stainless steel but also environmentally harmful element. A number of mineralogical phases present in the slag matrix can contain chromium and lead to chromium leaching. Chromium in slag if not stabilized, could oxidize to the cancerogenic hexavalent state, and leach out if exposed to acidic and oxygen rich environment. Other environmental concerns are slag dusting and chromium escape to the atmosphere. Despite the fact that there is a certain risk...

  14. Experimental investigation of basic oxygen furnace slag used as aggregate in asphalt mixture.

    Science.gov (United States)

    Xue, Yongjie; Wu, Shaopeng; Hou, Haobo; Zha, Jin

    2006-11-16

    Chinese researchers have commenced a great deal of researches on the development of application fields of basic oxygen steel making furnace slag (BOF slag) for many years. Lots of new applications and properties have been found, but few of them in asphalt mixture of road construction engineering. This paper discussed the feasibility of BOF steel slag used as aggregate in asphalt pavement by two points of view including BOF steel slag's physical and micro-properties as well as steel slag asphalt materials and pavement performances. For the former part, this paper mainly concerned the mechanochemistry and physical changes of the steel slag and studied it by performing XRD, SEM, TG and mercury porosimeter analysis and testing method. In the second part, this paper intended to use BOF steel slag as raw material, and design steel slag SMA mixture. By using traditional rutting test, soak wheel track and modified Lottman test, the high temperature stability and water resistance ability were tested. Single axes compression test and indirect tensile test were performed to evaluate the low temperature crack resistance performance and fatigue characteristic. Simultaneously, by observing steel slag SMA pavement which was paved successfully. A follow-up study to evaluate the performance of the experimental pavement confirmed that the experimental pavement was comparable with conventional asphalt pavement, even superior to the later in some aspects. All of above test results and analysis had only one main purpose that this paper validated the opinion that using BOF slag in asphalt concrete is feasible. So this paper suggested that treated and tested steel slag should be used in a more extensive range, especially in asphalt mixture paving projects in such an abundant steel slag resource region. PMID:16982138

  15. Alternative concrete based on alkali-activated slag

    Directory of Open Access Journals (Sweden)

    Puertas, F.

    2008-09-01

    Full Text Available This article reports the results of related to on the performance of concrete made with waterglass (Na2SiO3•nH2O + NaOH-activated Colombian granulated blast furnace slag. The mechanical strength and durability properties this alkali-activated slag concrete (AAS were compared to the properties of ordinary Portland cement concrete (OPC with the same proportion of binder, which ranged from 340 to 512 kg per m3 of concrete. The results indicated that increasing the proportion of slag led to improvements in the properties studied.El propósito de este artículo es dar a conocer los resultados de la evaluación del comportamiento de mezclas de hormigón producidas a partir de la activación con waterglass (Na2SiO3•nH2O + NaOH de una escoria siderúrgica granulada de alto horno colombiana. Las propiedades mecánicas y de durabilidad de los hormigones activados alcalinamente (AAS se comparan con las correspondientes mezclas de hormigón de cemento Portland (OPC producidas con igual proporción de ligante. Estas proporciones variaron entre 340 y 512 kg por m3 de hormigón. Los resultados obtenidos indican que incrementos en la proporción de la escoria contribuye a la mejora de las propiedades evaluadas.

  16. Alkali Aggregate Reaction in Alkali Slag Cement Mortars

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By means of "Mortar Bar Method",the ratio of cement to aggregate was kept as a constant 1∶2.25,the water-cement ratio of the mixture was 0.40,and six prism specimens were prepared for each batch of mixing proportions with dimensions of 10×10×60mm3 at 38±2℃ and RH≥95%, the influences of content and particle size of active aggregate, sort and content of alkali component and type of slag on the expansion ratios of alkali-activated slag cement(ASC) mortars due to alkali aggregate reaction(AAR) were studied. According to atomic absorption spectrometry,the amount of free alkali was measured in ASC mortars at 90d.The results show above factors affect AAR remarkably,but no dangerous AAR will occur in ASC system when the amount of active aggregate is below 15% and the mass fraction of alkali is not more than 5% (Na2O).Alkali participated in reaction as an independent component, and some hydrates containing alkali cations were produced, free alkalis in ASC system can be reduced enormously.Moreover,slag is an effective inhibitor, the possibility of generating dangerous AAR in ASC system is much lower at same conditions than that in ordinary Portland cement system.

  17. Simulation of past exposure in slag wool production.

    Science.gov (United States)

    Fallentin, B; Kamstrup, O

    1993-08-01

    A survey of the working conditions at a Danish slag wool production factory during the early technological phase in the 1940s is presented. No exposure data, however, are available for that period. So, a full-scale simulation of the past production of slag wool has been performed. Air monitoring was carried out in the working area around the cupola furnace. The aim was to measure exposure to air pollutants other than fibres. Such exposure might have confounded a possible association between lung cancer and exposure to fibres, in the early technological phase of slag wool production. The simulation experiment demonstrated exposure to PAH, a known lung carcinogen. The effect of other concurrent exposures is difficult to assess. Time-weighted average concentrations of particulate material ranged between 12.9 and 49.1 mg m-3 at the upper decks around the cupola. Corresponding concentrations of the dominant metals zinc and lead were 4.4-22.7 mg Zn m-3 and 0.9-4.7 mg Pb m-3. Significant concentrations of PAH up to 269 micrograms PAH m-3 (4 micrograms BaP m-3) occurred during ignition of the cupola furnace. The carbon monoxide level reached 270 ppm also during ignition. PMID:8379619

  18. Estimation of slagging in furnaces; Kuonaavuuden ennustaminen kivihiilen poelypoltossa

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, T.; Jaeaeskelaeinen, K.; Oeini, J.; Koskiahde, A.; Jokiniemi, J.; Pyykkoenen, J. [Imatran Voima Oy, Vantaa (Finland)

    1997-10-01

    Understanding and estimation of slagging in furnaces is essential in the design of new power plants with high steam values or in modifications like low-NO{sub x} retrofits in existing furnaces. Major slagging yields poor efficiency, difficult operation and high maintenance costs of the plant. The aim of the project is to develop a computational model for slagging in pulverized coal combustion. The model is based on Computer Controlled Scanning Electron Microscopy (CCSEM) analysis of mineral composition of the coal and physical models for behaviour of minerals inside a furnace. The analyzed mineral particles are classified to five composition classes and distributed to calculational coal particles if internal minerals of coal. The calculational coal particles and the external minerals are traced in the furnace to find out the behaviour of minerals inside the furnace. If the particle tracing indicates that the particle hits the heat transfer surface of the furnace the viscosity of the particle is determined to see if particle is sticky. The model will be implemented to 3D computational fluid dynamics based furnace simulation environment Ardemus which predicts the fluid dynamics, heat transfer and combustion in a furnace. (orig.)

  19. Stabilization effects of surplus soft clay with cement and GBF slag

    Institute of Scientific and Technical Information of China (English)

    LU Jiang; Chirdchanin MODMOLTIN; Katsutada ONITSUKA

    2004-01-01

    Utilization of industrial waste and surplus construction soft clay as construction material was recommended, and many attempts at geotechnical waste utilization were undertaken. This study aimed at the application of cement and a kind of industrial wastes, i.e. granulated blast furnace slag, on stabilization of surplus soft clay. The results showed that the cement and slag can successfully stabilize Ariake clays even though this high organic clay fails to be stabilized by lime and cement. Addition of slag in cement for stabilization induces higher strength than cement alone for longer curing time. The application of the cement with slag is more suitable than cement alone for stabilization because of economical consideration.

  20. The Early Strength of Slag Cements with Addition of Hydrate Microcrystals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The effect of hydrate microcrystals such as calcium silicate hydrates (CSH) and ettringite on the early strength of slag cements was studied.The authors explored the possibility of improving the early strength of the slag cement by applying crystal seed technology.It is shown that slag crystal seeds make the early strength of the cement increased due to the action of hydrate crystal seeds,which speed up the hydration of clinker minerals in the nucleation of ettringite.Therefore,the early strength of the slag cement is obviously improved.

  1. Use of ancient copper slags in Portland cement and alkali activated cement matrices.

    Science.gov (United States)

    Nazer, Amin; Payá, Jordi; Borrachero, María Victoria; Monzó, José

    2016-02-01

    Some Chilean copper slag dumps from the nineteenth century still remain, without a proposed use that encourages recycling and reduces environmental impact. In this paper, the copper slag abandoned in landfills is proposed as a new building material. The slags studied were taken from Playa Negra and Púquios dumps, both located in the region of Atacama in northern Chile. Pozzolanic activity in lime and Portland cement systems, as well as the alkali activation in pastes with copper slag cured at different temperatures, was studied. The reactivity of the slag was measured using thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), electrical conductivity and pH in aqueous suspension and Fourier Transform Infrared Spectroscopy (FTIR). Furthermore, copper slag-Portland cement mortars with the substitution of 25% (by weight) of cement by copper slag and alkali-activated slag mortars cured at 20 and 65 °C were made, to determine the compressive strength. The results indicate that the ancient copper slags studied have interesting binding properties for the construction sector. PMID:26615227

  2. Development of vibration style ladle slag detection methods and the key technologies

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Ladle slag carry-over detection technology (SCDT) is of important practical significance to steel continuous casting production (CCP),which can effectively improve the casting blank quality,increase molten steel yield ratio,and protract the service life of tundish.The current SCDT realization methods and their application circumstance were summarized,and their main problems during the course of factual production were pointed out.The difficult technical points of detection principle,digital signal processing for vibration style SCDT development were described.To aim at the problems of vibration style SCDT,such as low recognition stability and long applied adjustment time,its key technologies including water model experimental platform establishment,two-phase sink vortex entrapment mechanism,forced vibration response of shroud nozzle and steel stream shock vibration signal processing optimization were analyzed deeply,and the corresponding research route and advices were given.

  3. Effect of phase separation structure on cementitious reactivity of blast furnace slag

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Blast furnace slag samples with phase separation structure were prepared by re-melting and then water quenching process. By use of XRD,DTA and SEM technologies in combination with mechanical property experiment,the structure characteristics of samples were determined and their effects on cementitious reactivity were investigated. The results show that the samples with phase separation have better cementitious reactivity than sample with homogenous glass and sample with crystalline phases,which mainly contributes to its glass structure with coexistence of Ca-O rich phase and Si-O rich phase. Moreover,the amorphous samples possess hydrability which is affected by their formation process,since phase separation extends the range of possible Ca-rich crystalline phases.

  4. Effect of phase separation structure on cementitious reactivity of blast furnace slag

    Institute of Scientific and Technical Information of China (English)

    LI Yu; SUN HengHu; LIU XiaoMing; CUI ZengDi

    2009-01-01

    Blast furnace slag samples with phase separation structure were prepared by re-melting and then water quenching process. By use of XRD, DTA and SEM technologies in combination with mechanical prop-erty experiment, the structure characteristics of samples were determined and their effects on cemen-titious reactivity were investigated. The results show that the samples with phase separation have better cementitious reactivity than sample with homogenous glass and sample with crystalline phases, which mainly contributes to its grass structure with coexistence of Ca-O rich phase and Si-O rich phase. Moreover, the amorphous samples possess hydrability which is affected by their formation process, since phase separation extends the range of possible Ca-rich crystalline phases.

  5. Review of the current situation of the production development of slag wool%矿渣棉生产发展现状的综述

    Institute of Scientific and Technical Information of China (English)

    王旭; 袁守谦; 李海潮

    2014-01-01

    The-application-and-the-specific-process-of-slag-wool-are-introduced.Specific-applications-include-length-slag-wool-fibers,slag-wool-and-phenolic-resins-general-slag-wool-products-can-be-used-for-heating-equipment-and-pip-ing;but-insulation-of-various-slag-wools-is-achieved-in-different-conditions;moreover,slag-wool-acoustic-board-can-be-widely-used-in-fields-such-as-construction-and-engineering-decoration.Raw-melting-technology-include-cupola-melting,furnace-melting,electric-arc-furnace-melting;fiber-injection-molding-process-include-injection,centrifuga-tion,centrifugal-blowing;Finally,it-illustrates-the-necessity-of-the-development-of-mineral-wool.%介绍了矿渣棉的应用和具体工艺。具体应用为:长纤维矿渣棉、普通矿渣棉和酚醛树脂矿渣棉制品均可用于热力设备和管道,但其不同矿渣棉是在不同条件下实现保温的,矿渣棉吸声板可广泛用于建筑、工程装饰等方面。原料融制工艺有冲天炉熔制、池窑熔制、电弧炉的熔制;纤维成型工艺有喷吹法、离心法、离心吹制;最后说明了发展矿渣棉的必要性。

  6. Accelerated carbonation of steel slags using CO2 diluted sources: CO2 uptakes and energy requirements

    Directory of Open Access Journals (Sweden)

    Renato eBaciocchi

    2016-01-01

    Full Text Available This work presents the results of carbonation experiments performed on Basic Oxygen Furnace (BOF steel slag samples employing gas mixtures containing 40 and 10% CO2 vol. simulating the gaseous effluents of gasification and combustion processes respectively, as well as 100% CO2 for comparison purposes. Two routes were tested, the slurry phase (L/S=5 l/kg, T=100 °C and Ptot=10 bar and the thin film (L/S =0.3-0.4 l/kg, T=50 °C and Ptot=7-10 bar routes. For each one, the CO2 uptake achieved as a function of the reaction time was analyzed and on this basis the energy requirements associated to each carbonation route and gas mixture composition were estimated considering to store the CO2 emissions of a medium size natural gas fired power plant (20 MW. For the slurry phase route, maximum CO2 uptakes ranged from around 8% at 10% CO2, to 21.1% (BOF-a and 29.2% (BOF-b at 40% CO2 and 32.5% (BOF-a and 40.3% (BOF-b at 100% CO2. For the thin film route, maximum uptakes of 13% (BOF-c and 19.5% (BOF-d at 40% CO2, and 17.8% (BOF-c and 20.2% (BOF-d at 100% were attained. The energy requirements of the two analyzed process routes appeared to depend chiefly on the CO2 uptake of the slag. For both process route, the minimum overall energy requirements were found for the tests with 40% CO2 flows (i.e. 1400-1600 MJ/t CO2 for the slurry phase and 2220-2550 MJ/t CO2 for the thin film route.

  7. Effect of additives in reducing ash sintering and slagging in biomass combustion applications

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Liang

    2012-07-01

    The objective of this study was to investigate sintering and slagging behaviors of biofuels during combustion processes. Biofuels tested are derived from the agricultural sector, wood and furniture industry as well as from municipal sewage sludge. It was also the aim to test and evaluate additives that can prevent and abate biomass ash sintering by conducting laboratory and industrial scale tests. Sintering characteristics of sewage sludge ashes at elevated temperatures were investigated by means of different laboratory methods. Utilizing of phosphorus participation agents Al2(SO4)3 or Fe2(SO4)3 caused substantially high contents of aluminum or iron in the studied sewage sludge ashes, respectively. High initial melting temperatures over 1100 degrees C and low sintering tendencies were observed from the sewage sludge ashes rich in aluminum. It was related to presence and formation of the inert mineral phases such as aluminum oxide, quartz and calcium aluminum silicates in the aluminum rich sewage sludge ashes at elevated temperatures. A low melting temperature, about 994 degree C, was detected from the iron rich sewage sludge ash. Severe sintering of this sewage sludge ash was mainly due to generation of low temperature melting iron silicates, as results of interaction and re-assemblage of hematite (Fe2O3), quartz (SiO2) and alkali feldspars under heating. Fusion behaviors of corn cob ashes under rising temperatures were characterized. The work revealed that chemical compositions of corn cob ashes are dominated by potassium, silicon, chlorine and phosphorus. However, the relative concentrations of these principal elements are considerably different for three studied corn cob ashes, which have major influence on ash transformation reactions and sintering tendencies. Compared with the other two, the chemical composition of the Waimanalo corn cob (WCob) was characterized with the highest K/Cl, Si/(Ca+Mg) and (Si+P+K)/(Ca+Mg) molar ratios, which was favorable for

  8. Conditioning of spent ion-exchange resins followed by solidification in the alkali-slag long-lived matrix with an increased level of filling with resins

    Directory of Open Access Journals (Sweden)

    Svetlana Nikolaevna Skomorokhova

    2015-12-01

    Full Text Available The possibility for spent ion-exchange resins (IER of intermediate specific activity to be solidified in alkali-slag (geocement water-resistant matrixes with an increased level of filling with resins was studied. Comparative tests of the IER immobilization process were done for justifying the most technologically effective matrix material. We used three different alkali-slag cementing systems and the prepared simulated pulps of IER with the specific activity of 3×108 Bq/L, saturated with 137Cs radionuclide. The manufactured samples of the alkali-slag compounds, filled with IER at the level of 24-27% by weight, meet the regulatory requirements set in NP-019-15 code and feature better working quality parameters (mechanical strength: 5-14 MPa, leaching rate of 137Cs, Na, Ca: <2×10-4 g/cm2∙day on the 7th-10th day, mechanical strength of compounds rises by the factor of 1.2-1.5 after immersion tests. The incorporation of the spent IER in the most technologically effective alkali-slag matrix makes it possible to decrease the cementing material consumption by the factor of 2.4 in comparison with Portland cement and by the factor of 1.3 in comparison with the known slag binders, while a compound with better quality parameters is produced. The research was done with the support of the Russian Ministry of Education and Science (unique identifier of the applied research studies - RFMEFI57915X0101 for justifying a new energy-efficient and resource-saving technology of reprocessing the spent IER-containing waste.

  9. Accelerated Carbonation of Steel Slags Using CO2 Diluted Sources: CO2 Uptakes and Energy Requirements

    OpenAIRE

    Baciocchi, Renato; Costa, Giulia; Polettini, Alessandra; Pomi, Raffaella; Stramazzo, Alessio; Zingaretti, Daniela

    2016-01-01

    This work presents the results of carbonation experiments performed on Basic Oxygen Furnace (BOF) steel slag samples employing gas mixtures containing 40 and 10% CO2 vol. simulating the gaseous effluents of gasification and combustion processes respectively, as well as 100% CO2 for comparison purposes. Two routes were tested, the slurry-phase (L/S = 5 l/kg, T = 100°C and Ptot = 10 bar) and the thin-film (L/S = 0.3–0.4 l kg, T = 50°C and Ptot = 7–10 bar) routes. For each one, the CO2 uptake ac...

  10. Kinetics of Hydrochloric Acid Leaching of Titanium from Titanium-Bearing Electric Furnace Slag

    Science.gov (United States)

    Zheng, Fuqiang; Chen, Feng; Guo, Yufeng; Jiang, Tao; Travyanov, Andrew Yakovlevich; Qiu, Guanzhou

    2016-05-01

    The hydrochloric acid leaching of titanium from titanium-bearing electric furnace slag was investigated under different experimental conditions. The results indicate that particle size, hydrochloric acid concentration and reaction temperature were of significance to the leaching kinetics. Specifically, reaction temperature was the most important factor followed by hydrochloric acid concentration and particle size. The shrinking core model was used to describe the leaching process which was controlled by surface chemical reaction. The kinetic equation was obtained and the activation energy was found to be 43.16 kJ/mol. Iron and calcium species were almost completely dissolved in the acid when the extraction degree of titanium reached 99.84%. MgO (19.34 wt.%) and Al2O3 (32.45 wt.%) in the spinel were still in the leaching residue and SiO2 (43.53 wt.%) in the form of quartz remained in the leaching residue.

  11. Physico-chemical characterization of steel slag. Study of its behavior under simulated environmental conditions.

    Science.gov (United States)

    Navarro, Carla; Díaz, Mario; Villa-García, María A

    2010-07-15

    The chemical and mineralogical composition of steel slag produced in two ArcelorMittal steel plants located in the North of Spain, as well as the study of the influence of simulated environmental conditions on the properties of the slag stored in disposal areas, was carried out by elemental chemical analysis, XRF, X-ray diffraction, thermal analysis, and scanning electron microscopy with EDS analyzer. Spectroscopic characterization of the slag was also performed by using FTIR spectroscopy. Due to the potential uses of the slag as low cost adsorbent for water treatment and pollutants removal, its detailed textural characterization was carried out by nitrogen adsorption-desorption at 77 K and mercury intrusion porosimetry. The results show that the slag is a crystalline heterogeneous material whose main components are iron oxides, calcium (magnesium) compounds (hydroxide, oxide, silicates, and carbonate), elemental iron, and quartz. The slags are porous materials with specific surface area of 11 m(2)g(-1), containing both mesopores and macropores. Slag exposure to simulated environmental conditions lead to the formation of carbonate phases. Carbonation reduces the leaching of alkaline earth elements as well as the release of the harmful trace elements Cr (VI) and V. Steel slags with high contents of portlandite and calcium silicates are potential raw materials for CO(2) long-term storage. PMID:20568743

  12. Accelerated carbonation and leaching behavior of the slag from iron and steel making industry

    Institute of Scientific and Technical Information of China (English)

    Quanyuan Chen; D.C. Johnson; Lingyun Zhu; Menghong Yuan; C.D. Hills

    2007-01-01

    Ground granulated blast furnace slag (GGBFS) and steelmaking slag have been used as a raw material for cement production or as an aggregate to make concrete, which contribute aluminum, calcium, iron, and silicon oxides. The suitability of the slag for a particular application depends on its reactivity, cost, availability, and its influence on the properties of the resulting concrete. For the interest of durability studying of concrete in the presence of slag, the accelerated carbonation products and leaching behavior of the slag and Portland cement (PC) were studied. The experimental results confirmed that the slag was more resistant to carbonation compared to PC. The carbonation degree of GGBFS reduced by 17.74%; and the carbonation degrees of steelmaking slags reduced by 9.51%-11.94%. Carbonation neutralized the alkaline nature of the hydrated pastes and gave rise to the redox potential of the leachate slightly (30-77 mV). The carbonation also increased the release of most of the elements presented, except for calcium, to the aqueous environment. It is concluded that blend cements (PC plus slag) have economical advantages and better durability compared to PC.

  13. Assessment of the hydration constants of post blended blast furnace slag cements

    NARCIS (Netherlands)

    Visser, J.H.M.; Zon, Q.F. van; Beijersbergen van Henegouwen, J.F.; Hacquebord, A.; Zwet, R.G.A. van

    2014-01-01

    The amount of bound water in OPC i slag blends have been measured for three different temperature regimes: from 105 to 950°C, 400 to 600 oC and 600 to 950°C for three different OPCs and one type of slag, at 5 different replacement factor and at four ages. Based on the measured linear relationship be

  14. Heat Recovery from High Temperature Slags: A Review of Chemical Methods

    Directory of Open Access Journals (Sweden)

    Yongqi Sun

    2015-03-01

    Full Text Available Waste heat recovery from high temperature slags represents the latest potential way to remarkably reduce the energy consumption and CO2 emissions of the steel industry. The molten slags, in the temperature range of 1723–1923 K, carry large amounts of high quality energy. However, the heat recovery from slags faces several fundamental challenges, including their low thermal conductivity, inside crystallization, and discontinuous availability. During past decades, various chemical methods have been exploited and performed including methane reforming, coal and biomass gasification, and direct compositional modification and utilization of slags. These methods effectively meet the challenges mentioned before and help integrate the steel industry with other industrial sectors. During the heat recovery using chemical methods, slags can act as not only heat carriers but also as catalysts and reactants, which expands the field of utilization of slags. Fuel gas production using the waste heat accounts for the main R&D trend, through which the thermal heat in the slag could be transformed into high quality chemical energy in the fuel gas. Moreover, these chemical methods should be extended to an industrial scale to realize their commercial application, which is the only way by which the substantial energy in the slags could be extracted, i.e., amounting to 16 million tons of standard coal in China.

  15. Microstructure and Composition of Hydration Products of Ordinary Portland Cement with Ground Steel-making Slag

    Institute of Scientific and Technical Information of China (English)

    LI Yong-xin; CHEN Yi-min; ZHANG Hong-tao; HE Xing-yang; WEI Jiang-xiong; ZHANG Wen-sheng

    2003-01-01

    The effect of ground steel-making slag on microstructure and composition of hydration products of ordinary Portland cement (OPC) was investigated by mercury intrusion porosimetry ( MIP ), X- ray diffraction (XRD) and differential thermal analysis (DTA). Results show that ground steel-making slag is a kind of high activity mineral additives and it can raise the longer-age strength of OPC mortar. The total porosity and average pore diameter of OPC paste with groand steel-making slag increase with the increase of the amount of ground steelmaking slag replacing OPC at various ages, while after 28 days most pores in OPC paste with ground steel-making slag do not influeace the strength because the diameter of those pores is in the rang of 20 to 50nm. The hydration mechanism of ground steel-making slag is similar to that of OPC but different from that of fly ash and blast furnace slag. The hydration products of ground steel-making slag contain quite a lot of Ca( OH)2 in long age.

  16. Double Slag Operation Dephosphorization in BOF for Producing Low Phosphorus Steel

    Institute of Scientific and Technical Information of China (English)

    TIAN Zhi-hong; LI Ben-hai; ZHANG Xiao-ming; JIANG Zhong-hang

    2009-01-01

    A study on the production of low phosphorus steel by double slag operation in 210 t converter was carried out.A phosphorus content of less than 0.005% (mass percent) was obtained before tapping.About 80 % phosphorus could be removed by the first slag after 5 min.High Fe3+ content and high basicity in the first slag were in favor of dephosphorization.On the other hand,Fe3+ content had less effect on dephosphorization during second slag treatment.In the second slag period,the fraction of dephosphorization increased with the increase of basicity up to a basicity of 6.Further increase of basicity of the second slag had very little effect on dephosphorization.The tapping temperature had great impact on dephosphorization.It was impossible to get phosphorus less that 0.005% when the tapping temperature was higher than 1 943 K.The optimum operation conditions were suggested.On the basis of these conditions,the amount of the second slag and the effect of the remaining first slag were estimated.

  17. 基于电镜的生物质成型燃料锅炉结渣机理研究%The Slagging Mechanism Study of Biomass Briquette Boiler Based on Electron Microscopy

    Institute of Scientific and Technical Information of China (English)

    李文雅; 史改玲; 王喜云; 孙建中; 刘圣勇

    2014-01-01

    目前市场上已出现生物质成型燃料燃烧设备,由于结渣等因素影响,限制了这种生物质成型燃料燃烧设备的推广与应用。结渣不仅会对燃烧设备的热性能造成影响,而且危及燃烧设备的安全性。在生物质成型燃料炉渣电镜实验的基础上,揭示生物质成型燃料锅炉结渣的过程并得出预防和防止结渣措施。%At present,biomass briquette combustion equipments have been found on the market. But their promotion and application are restricted by some factors such as slagging and so on. Slagging will not only affect the thermal properties of combustion equipments,but also endanger the safety of combustion equipments. Based on the electrical microscopy experiment of biomass briquette slag,we revealed the slagging process of biomass briquette boilers,and found some measures on slagging prevention.

  18. Research on the stability of f-CaO content in desulfurization slag%固硫渣中f-CaO的含量测试及其安定性的研究

    Institute of Scientific and Technical Information of China (English)

    孙夔; 贺深阳; 贾韶辉; 吴双

    2015-01-01

    With the development of desulfurization technology for circulating fluidized bed boiler, large amounts of desulfurization slag is stored up. Desulfurization slag contains a lot of f-CaO and SO3, through the study of the content and digestion rate of f-CaO in desulfurization slag, and the test of the stability of the slag as a cement admixture and aggregate for concrete brick. The test shows that most f-CaO can be easily digested, and can’t affect the stability after the watering process, so that the slag can be used as mixture and aggregate for concrete brick.%随着循环流化床锅炉脱硫技术的发展,大量的固硫渣被堆存。固硫渣含有大量的f-CaO和SO3,通过对固硫渣中f-CaO含量和消解速度的研究,测试其作为水泥混合材和混凝土砖骨料制品时的安定性。结果表明:固硫渣中大部分f-CaO容易消解,经淋水处理以后不会对安定性产生不良影响,可用于水泥混合材和混凝土砖骨料。

  19. Effect of Slag on Titanium, Silicon, and Aluminum Contents in Superalloy During Electroslag Remelting

    Science.gov (United States)

    Jiang, Zhou-Hua; Hou, Dong; Dong, Yan-Wu; Cao, Yu-Long; Cao, Hai-Bo; Gong, Wei

    2016-04-01

    Many factors influence the chemical composition in electroslag remelting (ESR) steel, including atmosphere in crucible, melting rate, slag composition, deoxidation, and so on. Fluoride-based slag, which is exposed to liquid metal directly, influences the chemical composition of ESR ingots to a large extent. The present paper focuses on the effect of slag on the titanium, silicon, and aluminum contents in ingots based on the interaction of the slag and metal. In present work, superalloy of GH8825 and several slags containing different CaO contents have been employed for investigating the effect of slag on titanium, silicon, and aluminum contents in an electrical resistance furnace under argon atmosphere. Results indicate that the higher CaO content in slag has better capacity for avoiding loss of titanium caused by the reaction of titanium with silica in slag, especially in case of remelting superalloy with high titanium and low silicon content. The CaO has a great effect on the activities of TiO2, SiO2, and Al2O3. Thermodynamic analysis is applied to investigate the CaO behavior. Based on the ion and molecule coexistence theory of slag, activity model is established to calculate the activities of components containing titanium, silicon, and aluminum elements in a six-component slag consisting of CaO-CaF2-Al2O3-SiO2-TiO2-MgO. The components containing titanium, silicon, and aluminum in slag are mainly CaO·TiO2, 2CaO·SiO2, CaO·SiO2, CaO·Al2O3, and MgO·Al2O3. With the increase of CaO mass fraction in slag, the activity coefficient of SiO2 decreases significantly, whereas slightly change happens for Al2O3. As a result, the lg ({{γ_{{{{SiO}}2 }} } {/ {{{γ_{{{{SiO}}2 }} } {γ_{{{{TiO}}2 }} }}} {γ_{{{{TiO}}2 }} }}) decreases with increasing CaO content, which is better for preventing loss of titanium caused by the reaction of titanium with silica in slag. The slag with high CaO and appropriate TiO2 content is suitable for electroslag remelting of GH8825.

  20. Fabrication of slag-glass composite with controlled porosity

    Directory of Open Access Journals (Sweden)

    Ranko Adziski

    2008-06-01

    Full Text Available The preparation and performance of porous ceramics made from waste materials were investigated. Slag from thermal electrical plant Kakanj (Bosnia and Herzegovina with defined granulations: (0.500÷0.250 mm; (0.250÷0.125 mm; (0.125÷0.063 mm; (0.063÷0.045 mm and 20/10 wt.% of the waste TV screen glass with a granulation <0.063 mm were used for obtaining slag-glass composites with controlled porosity. The one produced from the slag powder fraction (0.125÷0.063 mm and 20 wt.% TV screen glass, sintered at 950°C/2h, was considered as the optimal. This system possesses open porosity of 26.8±1.0%, and interconnected pores with the size of 250–400 μm. The values of E-modulus and bending strength of this composite were 10.6±0.6 GPa and 45.7±0.7 MPa, respectively. The coefficient of thermal expansion was 8.47·10-6/°C. The mass loss in 0.1M HCl solution after 30 days was 1.2 wt.%. The permeability and the form coefficient of the porous composite were K0=0.12 Da and C0=4.53·105 m-1, respectively. The porous composite shows great potential to be used as filters, diffusers for water aeration, dust collectors, acoustic absorbers, etc.

  1. Biomass fuel leaching for the control of fouling, slagging, and agglomeration in biomass power generation

    Science.gov (United States)

    Bakker, Robert Reurd

    The use of straws and other herbaceous biomass as boiler fuel is limited because of rapid formation of boiler deposits (i.e. fouling and slagging), which results in high boiler operating costs. The removal of troublesome elements in biomass that lead to slagging and fouling was tested by washing (leaching) biomass fuels in water. Potassium, sodium, and chlorine are easily removed from rice straw and other biomass in both tap and distilled water. Simple water leaching leads to considerable changes in combustion properties and ash transformation in biomass. In general, leaching elevates the sintering and melting temperatures, improves ash fusibility, and reduces the volatilization of inorganic species. Leaching leads to a notable decline in the alkali index, a broad indicator of the fouling potential of a biomass fuel. Bench-scale combustion tests at 800-1000°C furnace gas temperatures confirm that leaching dramatically changes the combustion behavior of rice straw. Full-scale combustion tests indicate that leached rice straw is technically suitable under normal boiler operating conditions. Two potential strategies to accomplish leaching of rice straw include leaching under controlled circumstances, and leaching by natural precipitation. Under controlled conditions, substantial amounts of K and Cl can be leached from rice straw with water at ambient temperatures, and without extensive particle size reduction. Leaching straw in a full-scale process is estimated to add approximately $15 to 18 Mg-1 to the fuel costs of a combustion facility. Leaving rice straw in the field and exposed to rainy weather leads to similar improvements in combustion behavior as observed with biomass that is leached under controlled circumstances. Collection of naturally leached rice straw in the Sacramento Valley through delayed harvesting is technically feasible, however its commercial implementation is dependent on harvest practices, rainfall distribution, and field-specific factors. The

  2. Distinctive microstructural features of aged sodium silicate-activated slag concretes

    Energy Technology Data Exchange (ETDEWEB)

    San Nicolas, Rackel [Department of Chemical and Biomolecular Engineering, University of Melbourne, Victoria 3010 (Australia); Bernal, Susan A. [Department of Materials Science and Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin St, Sheffield S1 3JD (United Kingdom); School of Materials Engineering, Composite Materials Group, Universidad del Valle, Cali (Colombia); Mejía de Gutiérrez, Ruby [School of Materials Engineering, Composite Materials Group, Universidad del Valle, Cali (Colombia); Deventer, Jannie S.J. van [Department of Chemical and Biomolecular Engineering, University of Melbourne, Victoria 3010 (Australia); Zeobond Pty Ltd, P.O. Box 23450, Docklands, Victoria 8012 (Australia); Provis, John L., E-mail: j.provis@sheffield.ac.uk [Department of Materials Science and Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin St, Sheffield S1 3JD (United Kingdom)

    2014-11-15

    Electron microscopic characterisation of 7-year old alkali-activated blast-furnace slag concretes enabled the identification of distinct microstructural features, providing insight into the mechanisms by which these materials evolve over time. Backscattered electron images show the formation of Liesegang-type ring formations, suggesting that the reaction at advanced age is likely to follow an Oswald supersaturation–nucleation–depletion cycle. Segregation of Ca-rich veins, related to the formation of Ca(OH){sub 2}, is observed in microcracked regions due to the ongoing reaction between the pore solution and available calcium from remnant slag grains. A highly dense and uniform interfacial transition zone is identified between siliceous aggregate particles and the alkali activated slag binders, across the concretes assessed. Alkali-activated slag concretes retain a highly dense and stable microstructure at advanced ages, where any microcracks induced at early ages seem to be partially closing, and the remnant slag grains continue reacting.

  3. Cementing properties of steel slag activated by sodium silicates and sodium hydroxide

    Institute of Scientific and Technical Information of China (English)

    Wen Ni; En Wang; Jianping Li; Han Sun

    2005-01-01

    Steel slag which is mainly composed of γ-CasSiO4 and other silicates or alumino-silicates is activated by sodium silicates and sodium hydroxide. The powders of such steel slag are usually inert to hydrate and subsequently have very low ability of cementing. But when sodium silicates and sodium hydroxide are used as activators the steel slag shows very good properties of cementing. When activated with NaOH solution the hardened slurry of the steel slag has a compressive strength of 11.13 MPa after being cured for 28 days. When activated with Na2SiO3 solution the samples after being cured for 28 days have an average compressive strength of 40.23 MPa. While the steel slag slurry which is only mixed with water has a compressive of 0.88 MPa after being cured for 28 days.

  4. The Effect of Oxygen Potential on the Sulfide Capacity for Slags Containing Multivalent Species

    Science.gov (United States)

    Allertz, Carl; Selleby, Malin; Sichen, Du

    2016-06-01

    The dependence of sulfide capacity on the oxygen partial pressure for slags containing multivalent species was investigated experimentally using a slag containing vanadium oxide. Copper-slag equilibration experiments were carried out at 1873 K (1600 °C) in the approximate oxygen partial pressure range 10-15.4 to 10-9 atm. The sulfide capacity was found to be strongly dependent on the oxygen potential in this slag system, increasing with the oxygen partial pressure. The sulfide capacity changed by more than two orders of magnitude over the oxygen partial pressure range. The effect of changing oxygen partial pressure was found to be much greater than the effect of changing slag composition at a fixed oxygen partial pressure.

  5. Strength and Drying Shrinkage of Alkali-Activated Slag Paste and Mortar

    Directory of Open Access Journals (Sweden)

    Mao-chieh Chi

    2012-01-01

    Full Text Available The aim of this study is to investigate the strengths and drying shrinkage of alkali-activated slag paste and mortar. Compressive strength, tensile strength, and drying shrinkage of alkali-activated slag paste and mortar were measured with various liquid/slag ratios, sand/slag ratios, curing ages, and curing temperatures. Experimental results show that the higher compressive strength and tensile strength have been observed in the higher curing temperature. At the age of 56 days, AAS mortars show higher compressive strength than Portland cement mortars and AAS mortars with liquid/slag ratio of 0.54 have the highest tensile strength in all AAS mortars. In addition, AAS pastes of the drying shrinkage are higher than AAS mortars. Meanwhile, higher drying shrinkage was observed in AAS mortars than that observed comparable Portland cement mortars.

  6. Reduction chlorination of slag containing niobium, tantalum and titanium

    International Nuclear Information System (INIS)

    Reduction chlorination experiments were carried out with slag containing niobium, tantalum in order to evaluate the effects of some variables on the behaviour of the material. Kinetic curves were obtained with the main variables being temperature and percentage of reducing agent. The results showed a greater effect of temperature as well as indicated the formation of the non-volatile chlorides (CaCl2) as a factor reducing the reaction rate. Quantitative analyses of the material collected in the condenser indicated the viability of the method to recover the valuable metals. (Author)

  7. Performance of alkaline activated slag at high temperatures

    OpenAIRE

    Mejía de Gutiérrez, R.; Maldonado, J.; C. Gutiérrez

    2004-01-01

    This paper presents an investigation into the performance of alkali-activated slag (AAS) mortar exposed to elevated temperatures. Sodium silicate, sodium hydroxide and a mix (waterglass) with a modulus (SiO2/Na20) of 1.5 were used as activators. The specimens were heated in an electric furnace up to 1000 ºC in steps of 200 ºC for a constant period of 2 hours. The weight loss, residual compressive strength, resistance to chloride ion penetration, p...

  8. Reduction of vanadium oxide by carbon in stainless steelmaking slags

    Energy Technology Data Exchange (ETDEWEB)

    Divakar, M.; Lahiri, A.K. [Indian Inst. of Science, Bangalore (India). Dept. of Metallurgy; Goernerup, M. [Uddeholm Technology AB (Sweden)

    2001-02-01

    Simultaneous reduction of chromium, iron and vanadium oxides by carbon has been studied by conducting experiments on typical stainless steelmaking slags in the temperature range of 1823 to 1923 K. In-situ gas generated due to the reduction led to several phenomena such as foam/emulsion formation, change in foam height, size of gas bubbles and rate of gas generation. The kinetics of vanadium oxide reduction by carbon are studied under the influence of the above mentioned phenomena and the presence of chromium and iron oxides. (orig.)

  9. Computer recognition of slag property diagrams in ternary systems

    Institute of Scientific and Technical Information of China (English)

    Jinxiong Lu; Li Wang; Jiongming Zhang; Xinhua Wang

    2004-01-01

    In order to take data information from the slag property diagram in a ternary system automatically and actually, a picture recognition and drawing software has been developed by Visual Basic 6.0 based on the image coding principle of computer system and the graphics programming method of VB. This software can transform the ternary system isopleth diagram from bitmap format to data file and establish a corresponding database which can be applied to rapidly retrieve a mass of data and make correlative thermodynamics or kinetics calculation. Besides, it still has the function of drawing the ternary system diagram which can draw different kinds of property parameters in the same diagram.

  10. Alkali-activated blast furnace slag-zeolite cements and concretes

    International Nuclear Information System (INIS)

    The aim of this work has been the study of alkali-activated slag-zeolite cements and concretes based on them. Various compositions have been tested and some characteristics such as the compressive strength have been measured versus zeolite additions. A table lists the specific surface area and particle size distributions of different cements. The conclusions of the study are the following. First, alkali-activated slag cements and concretes based on them are effective for immobilization of radioactive wastes and the production of building structures, designed for high radiation load. Secondly, zeolite-containing mineral additions are able to increase the immobilization capacity and radiation resistance of alkali-activated blast furnace slag cements and concretes. Thirdly, the efficiency of different zeolite-containing additions - 10% to increase alkali-activated blast furnace slag-zeolite cement strength was established. It is with alkaline components of water-glass, sodium carbonate, sodium sulphate. Fourth, the effective way of introducing zeolite additions in alkali-activated blast furnace slag-zeolite cement is inter-grinding of the slag and addition. Increase in strength of alkali-activated blast furnace slag-zeolite cement stone is 40% higher than that of the stone of a mixture of separately milled components. Fifth, Alkali-activated blast furnace slag-zeolite cements with zeolite-containing additions with a compressive strength of 10.1 to 140 MPa; alkali-activated blast furnace slag-zeolite cements mortars with compressive strength from 35.2 to 97.7 MPa; alkali-activated blast furnace slag-zeolite cements concretes with compressive strength up to 84.5 MPa and frost resistant up to 800 cycles were obtained

  11. INFLUENCE OF CURING TEMPERATURE ON THE PHYSICO-MECHANICAL, CHARACTERISTICS OF CALCIUM ALUMINATE CEMENT WITH AIR-COOLED SLAG OR WATER-COOLED SLAG

    Directory of Open Access Journals (Sweden)

    M. Heikal

    2004-12-01

    Full Text Available The nature, sequence, crystallinity and microstructure of hydrated phases were analyzed using differential scanning calorimetry (DSC, X-ray diffraction (XRD and scanning electron microscopy (SEM. The results showed that the formation of different hydrated phases was temperature dependence. The physico-mechanical and microstructural characteristics were investigated after curing at 20, 40 and 60° C. The results indicated that for the substitution of calcium aluminate cement (CAC by air-cooled slag (AS or water-cooled slag (WS at 20° C, the compressive strength increases with slag content up to 10 wt.%, then followed by a decrease with further slag substitution up to 25 wt.%; but the values are still higher than those of the neat CAC pastes at different curing ages up to 60 days. After 28 days of hydration at 40-60° C, the compressive strength increases with the slag content. This is attributed to the prevention of the conversion reaction, which was confirmed by XRD, DSC and SEM techniques, and the preferential formation of stratlingite (gehleinte-like phase. The SEM micrographs showed a close texture of hydrated CAC/slag blends made with AS or WS at 40°C due to the formation of C2ASH8 and C-S-H phases.

  12. An annular-furnace boiler for the 660-MW power unit for ultrasupercritical parameters intended for firing brown slagging coals

    Science.gov (United States)

    Serant, F. A.; Belorutskii, I. Yu.; Ershov, Yu. A.; Gordeev, V. V.; Stavskaya, O. I.; Katsel, T. V.

    2013-12-01

    We present the main technical solutions adopted in designing annular-furnace boilers intended for operation on brown coals of the prospective Maikubensk open-cast mine in Kazakhstan as part of 660-MW power units for ultrasupercritical steam conditions. Results from 3D modeling of combustion processes are presented, which clearly show the advantages furnaces of this kind have over a traditional furnace in burning heavily slagging brown coals. The layout of the main and boiler auxiliary equipment in the existing boiler cell of the 500-MW power unit at the Ekibastuz GRES-1 district power station is shown. Appropriate attention is paid to matters concerned with decreasing harmful emissions.

  13. Mechanical property and hydration mechanism of slag blended magnesium phosphate cement%矿渣磷酸镁水泥的力学性能和水化机理

    Institute of Scientific and Technical Information of China (English)

    侯磊; 李金洪; 王浩林

    2011-01-01

    以高炉矿渣作为磷酸镁水泥(MPC)的活性混合材料,研究了MPC的凝固时间、力学性能、物相组成和显微结构,并探讨了矿渣MPC的作用机理.实验固定磷镁比为25%,硼镁比为7.5%,矿渣掺量分别为磷镁总质量的0%、10%、20%、30%和40%.结果表明,矿渣参与了水化反应并提高了MPC的胶凝性能,随着矿渣掺量增大,矿渣MPC的抗压强度提高,但矿渣水化产生的膨胀应力会破坏MPC的内部结构,因此其抗折强度随矿渣掺量增大而降低.矿渣MPC的主要水化产物为六水合磷酸镁铵(MgNH4PO4·6 H2O),矿渣的掺入使凝胶相增加,并有部分Ca2+进入MgNH4PO4·6 H2O品格,使水化产物的形貌、大小发生变化.样品中剩余较多死烧镁和矿渣颗粒,可起骨料作用.%Blast-furnace slag was used as an active addition of magnesium phosphate cement. The influence of blast-furnace slag on the setting time, mechanical property, mineral phase and microstucture of slag blended magnesium phosphate cement (MPC) was studied. The prescription was designed as follows: the ratio of monoammonium phosphate to magnesia was 25% in mass, the borax additive amount to magnesia was 7.5% , the additive amount of blast-furnace slag was 0% , 10%, 20%, 30% and 40% separately in the ratio of total amount of dead burned magnesia and monoammonium phosphate to MPC. The results show that slag might participate the hydration, which improves the bonding of MPC, and the compressive strength of slag-blended MPC is improved with the increasing additive amount of slag. However, slag might results in expansion stress during hydration process, which causes lattice disturbance in hardened MPC, so the flexual strength decreases with the increasing additive amount of slag at the same time. The main hydration product of slag blended MPC is struvite (MgNH4PO4·6 H2O), the content of amorphous phase might increase after being mixed with slag in MPC, and Ca2+ ions in slag can result

  14. Mechanical and leaching behaviour of slag-cement and lime-activated slag stabilised/solidified contaminated soil.

    Science.gov (United States)

    Kogbara, Reginald B; Al-Tabbaa, Abir

    2011-05-01

    Stabilisation/solidification (S/S) is an effective technique for reducing the leachability of contaminants in soils. Very few studies have investigated the use of ground granulated blast furnace slag (GGBS) for S/S treatment of contaminated soils, although it has been shown to be effective in ground improvement. This study sought to investigate the potential of GGBS activated by cement and lime for S/S treatment of a mixed contaminated soil. A sandy soil spiked with 3000mg/kg each of a cocktail of heavy metals (Cd, Ni, Zn, Cu and Pb) and 10,000mg/kg of diesel was treated with binder blends of one part hydrated lime to four parts GGBS (lime-slag), and one part cement to nine parts GGBS (slag-cement). Three binder dosages, 5, 10 and 20% (m/m) were used and contaminated soil-cement samples were compacted to their optimum water contents. The effectiveness of the treatment was assessed using unconfined compressive strength (UCS), permeability and acid neutralisation capacity (ANC) tests with determination of contaminant leachability at the different acid additions. UCS values of up to 800kPa were recorded at 28days. The lowest coefficient of permeability recorded was 5×10(-9)m/s. With up to 20% binder dosage, the leachability of the contaminants was reduced to meet relevant environmental quality standards and landfill waste acceptance criteria. The pH-dependent leachability of the metals decreased over time. The results show that GGBS activated by cement and lime would be effective in reducing the leachability of contaminants in contaminated soils. PMID:21420148

  15. Study of glass ceramic material on the base of ash group simulating slag of plasma shaft furnace for high temperature reprocessing of radioactive wastes

    International Nuclear Information System (INIS)

    Using the methods of X-ray diffraction, differential thermal and micro-probe analysis it is shown that the processes of minerals formation and homogenization in ash residue based charge under the heating up to 1450 deg C take place with a high rate and completely finish during 10 minutes. Homogeneous materials containing besides glassy phase crystalline phases and metallic shots are formed in this process. The products obtained with fluxes (dolomite and clay) additions are more homogeneous than a flux-less fused slag. Losses of α-radioactive nuclides during the melting of ash residue at 1300 deg C do not exceed 1.5% and is likely attributed with the products of uranium decay. Hydrolytic stability of the slags estimated from the rate of α-radioactive elements lixiviation is on the level of (1.4-5.7)x10-4 g/(cm2 x day) at 95 deg C

  16. Effects of Converter Slag on some Chemical Characteristics of Acid Soils

    Directory of Open Access Journals (Sweden)

    H. Shariatmadari

    2005-01-01

    Full Text Available Lintz-Donawitz (LD converter slag, a by-product of the iron and steel-making industry is produced in large quantities in Isfahan, Iran. The slag contains 52.8 and 2.2% (w/w CaO and MgO, respectively. To determine the influence of LD slag on the chemical characteristics of three acid soils from Gilan, an incubation study was conducted. The soil samples were collected from 0-30 cm of rice and tobacco fields and a tea garden. Treatments were 0, 0.5, 1, 2, 4, 8 and 16 % (w/w of converter slag/kg soil. The slag was thoroughly mixed with 500g soil in plastic pots. Soil moisture content was adjusted to near field capacity and changes in pH, EC and AB-DTPA-extractable Fe, Mn, Zn, P and K were determined at 1, 10, 30 and 60 days. Results showed that soil pH increased with increasing slag rates. Slag increased AB-DTPA-extractable P and Mn, the magnitude increase depend on the amount of slag applied. However, the effect of slag on AB-DTPA-extractable Fe depended on initial pH, initially decreasing at the pH range of 7.4 - 8.5 and then increasing at higher pH levels. Slag decreased AB-DTPA-extractable K especially in highly acid soil. In the present study, soil pH and AB-DTPA-extractable Fe decreased with time, though the effect of incubation time on pH was not significant. The effect of incubation time on AB-DTPA extractable Mn and P was different. Time effect on EC and AB-DTPA-extractable K was not significant. In general, soil chemical characteristics were more affected by slag rates than by incubation time. In conclusion, it seems that converter slag is a suitable amendment for acid soils. It is suggested that the effect of LD converter slag on plant growth and chemical characteristics of acid soils be studied under field conditions.

  17. Soil Stabilisation Using Ground Granulated Blast Furnace Slag

    Directory of Open Access Journals (Sweden)

    Ashish Kumar Pathak

    2014-05-01

    Full Text Available Stabilisation is a broad sense for the various methods employed and modifying the properties of a soil to improve its engineering performance and used for a variety of engineering works. In today‟s day soil stabilisation is the major problem for civil engineers, either for construction of road and also for increasing the strength or stability of soil and reduces the construction cost. In this thesis the soil are stabilised by ground granulated blast furnace slag (GGBS and this material is obtained from the blast furnace of cement plant, which is the byproduct of iron (from ACC plant, sindri. It is generally obtained in three shaped one is air cooled, foamed shaped and another is in granulated shaped. The use of by-product materials for stabilisation has environmental and economic benefits. Ground granulated blast furnace slag (GGBS material is used in the current work to stabilise soil (clay. The main objectives of this research were to investigate the effect of GGBS on the engineering property (optimum moisture content and maximum dry density, plastic limit, liquid limit, compaction, unconfined compressive strength, triaxial and California bearing ratio test of the soil and determine the engineering properties of the stabilised.

  18. Effects of the slag former on the metal melting and radionuclides distribution in an electric arc furnace

    Energy Technology Data Exchange (ETDEWEB)

    Song, Song Pyung; Min, Byung Youn; Choi, Wang Kyu; Chung, Chong Hun; Oh, Won Zin [Korea Atomic Energy Research Institute, Taejeon (Korea, Republic of)

    2005-11-15

    The characteristics of the metal melting and radionuclide distribution of the radioactive has been investigated in a lab-scale arc furnace. The slag former based on the constituents of silica, calcium oxide, aluminum oxide, borate and calcium fluoride additions was used for melting of the stainless and carbon steel. In the melting of the stainless steel, the amount of slag formation increased with an increase of the concentration of the slag former. But the effects of the slag basicity on the amount of slag formation showed a local maximum value of the slag formation with an increase of the basicity index in the melting of the stainless steel as well as in the melting of the carbon steel. With an increase of the amount of slag former addition, the trends of the cobalt distribution into the ingot and the slag depended on the kind of slag former used in the melting of the stainless steel while the effect of the slag basicity on the distribution of the cobalt was not clarified in the melting of carbon steel. In the melting of the carbon steel, the strontium was captured at up to 50% into the slag phase. Cesium was completely eliminated from the melt of the stainless steel as well as the carbon steel and distributed to the dust phase.

  19. Effects of the slag former on the metal melting and radionuclides distribution in an electric arc furnace

    International Nuclear Information System (INIS)

    The characteristics of the metal melting and radionuclide distribution of the radioactive has been investigated in a lab-scale arc furnace. The slag former based on the constituents of silica, calcium oxide, aluminum oxide, borate and calcium fluoride additions was used for melting of the stainless and carbon steel. In the melting of the stainless steel, the amount of slag formation increased with an increase of the concentration of the slag former. But the effects of the slag basicity on the amount of slag formation showed a local maximum value of the slag formation with an increase of the basicity index in the melting of the stainless steel as well as in the melting of the carbon steel. With an increase of the amount of slag former addition, the trends of the cobalt distribution into the ingot and the slag depended on the kind of slag former used in the melting of the stainless steel while the effect of the slag basicity on the distribution of the cobalt was not clarified in the melting of carbon steel. In the melting of the carbon steel, the strontium was captured at up to 50% into the slag phase. Cesium was completely eliminated from the melt of the stainless steel as well as the carbon steel and distributed to the dust phase

  20. Survey and conceptual flow sheets for coal conversion plant handling-preparation and ash/slag removal operations

    Energy Technology Data Exchange (ETDEWEB)

    Zapp, F.C.; Thomas, O.W.; Silverman, M.D.; Dyslin, D.A.; Holmes, J.M.

    1980-03-01

    This study was undertaken at the request of the Fossil Fuel Processing Division of the Department of Energy. The report includes a compilation of conceptual flow sheets, including major equipment lists, and the results of an availability survey of potential suppliers of equipment associated with the coal and ash/slag operations that will be required by future large coal conversion plant complexes. Conversion plant flow sheet operations and related equipment requirements were based on two representative bituminous coals - Pittsburgh and Kentucky No. 9 - and on nine coal conversion processes. It appears that almost all coal handling and preparation and ash/slag removal equipment covered by this survey, with the exception of some coal comminution equipment, either is on hand or can readily be fabricated to meet coal conversion plant capacity requirements of up to 50,000 short tons per day. Equipment capable of handling even larger capacities can be developed. This approach appears to be unjustified, however, because in many cases a reasonable or optimum number of trains of equipment must be considered when designing a conversion plant complex. The actual number of trains of equipment selected will be influenced by the total requied capacity of the complex, the minimum on-line capacity that can be tolerated in case of equipment failure, reliability of specific equipment types, and the number of reactors and related feed injection stations needed for the specific conversion process.

  1. Sliding Wear Properties of Hybrid Aluminium Composite Reinforced by Particles of Palm Shell Activated Carbon and Slag

    Directory of Open Access Journals (Sweden)

    Zamri Yusoff

    2011-09-01

    Full Text Available In present work, dry sliding wear tests were conducted on hybrid composite reinforced with natural carbon based particles such as palm shell activated carbon (PSAC and slag. Hybrid composites containing 5 -20 wt.% of both reinforcements with average particles sizes about 125μm were prepared by conventional powder metallurgy technique, which involves the steps of mixing, compacting and sintering. Dry sliding experiments were conducted in air at room temperature using a pin-on-disc self-built attach to polisher machine. The disc which acted as the mating surface material was made of mild steel (120 HV cut from commercial mild steel sheet (2 mm thickness into 100mm diameter. The influence of the applied load was investigated under a constant sliding velocity of 0.1m/s with the applied loads at 3N, 11N and 51N. The contribution of the reinforcement content and the applied load as well as the sliding distance on the wear process and the wear rate have been investigated. The contribution of synergic factors such as applied load, sliding distance and reinforcement content (wt.% have been studied using analysis of variance (ANOVA. All synergic factors contribute to the wear process of all tested composites. Among synergic factors, the applied load is the highest contribution to wear process on both composites (Al/PSAC and Al/Slag and hybrid composite. The degree of improvement of wear resistance of hybrid composite is strongly dependent on the reinforcement content.

  2. Environmental impact and potential utilization of historical Cu-Fe-Co slags.

    Science.gov (United States)

    Veselská, Veronika; Majzlan, Juraj

    2016-04-01

    Historical slags from the past Fe and Cu-Co production were investigated in order to evaluate either their potential for utilization or their long-term environmental risk for unsupervised old smelting areas. Here, we studied ferrous slags produced during the recovery of Fe from siderite-Cu ores in Slovakia and two different types of non-ferrous slags produced during the recovery of Cu and Co from Kupferschiefer ores in Germany. The glassy character, rare occurrence of primary silicate phases, and the lack of secondary phases in Cu slags indicate their stability for a prolonged period of time. Electron microprobe analytical work showed that the metals and metalloids (Cu, Co, Fe, Zn, Pb, As) are largely encased in droplets of matte and metal alloys and remain protected by the glassy matrix with its low weathering rate. Fe and Co slags are composed of high-temperature silicates such as wollastonite, cristobalite, as well as olivine, feldspar, quartz, leucite, pyroxene, and pyroxenoids. The presence of secondary phases attests to a certain degree metal release owing to weathering. Assuming minimal contents of metals in slags after a treatment with dilute H2SO4, slags could be used as pozzolanas for addition to cement. PMID:26681328

  3. Effect of Water Vapor on O2- Content in Ironmaking Slag

    Institute of Scientific and Technical Information of China (English)

    Yousef MOHASSAB; Hong-yong SOHN

    2015-01-01

    In principle, slag basicity can be expressed as the concentration of free oxygen (O2−) in the slag system. This free oxygen content is equilibrated with different silicate anions in addition to other components in the silicate-based slags. X-ray photon spec-troscopy (XPS) and scanning electron microscope equipped with energy dispersive spectrometer (SEM-EDS) were used to investi-gate the effect of water vapor on the free oxygen content in ironmaking slags. It was found that water in the gas atmosphere plays a signiifcant role in the silicate anion equilibria. Water decreases the amount of free oxygen in the studied slags, with the free oxygen expressed as percentage of the total oxygen decreasing in the order of the following gas mixtures: CO+CO2 (44%,pH2O = 0 kPa) > CO+CO2+H2+H2O (41%,pH2O = 10.13 kPa) > H2+H2O (37%,pH2O = 14.19 kPa). The content of free oxygen ion affects the distribu-tion of elements such as sulfur, phosphorus, and manganese. In addition, it affects the iron oxide content in the slag as well as the interaction between slag and furnace lining.

  4. Investigation on the Copper Content of Matte Smelting Slag in Peirce-Smith Converter

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The copper contents and its existing forms in the slags duri ng the slag-making stage of Peirce-Smith converters in Guixi Smelter, Jiangxi Province, China have been investigated. The investigation was based on plant trials with the corresponding thermodynamic calculation s and kinetic considerations. From the plant data, the total copper co ntent in the slags was in the range of 2% to 8 % (mass fraction). The mechanical entrainment of matte drops has been found to be the main ca use of the copper loss. The suspension index, defined as the ratio of the mass fraction of copper in suspended matte drops in the slag to th at in bulk of the matte phase, has been adopted to quantify the matte entrainment. The values of this parameter estimated in this work have been found mainly within a range of 2.5%€?.0%. The Fe3O4 content in t he slag has been estimated to be the most important factor, among othe rs, influencing the separation of slag with matte and, consequently, t he copper loss from the slag.

  5. A Proposal for a Novel Method to Measure the Diffusivity of Species in Slag

    Science.gov (United States)

    Muhmood, Luckman; Viswanathan, Nurni Neelakantan; Seetharaman, Seshadri

    2011-04-01

    The rate of reactions involved in steel-refining operations largely depend on the transport of species through the slag or metal phase at steel refining temperatures; the intrinsic reaction rates are expected to be high. Therefore, the study of diffusivity of species in slag is of great importance. The present work proposes a new methodology, in which experiments can be designed to determine the diffusivity of species in liquid slag. In this article, a mathematical description for the methodology is formulated and subsequently solved using numerical methods. This exercise will help in identifying appropriate bounds for experimental parameters for a desired accuracy. The proposed methodology is generic for any species in the liquid slag phase. However, diffusion of sulfur through slag has been illustrated as a case study. The order of magnitude for the diffusion coefficient for sulfur was taken from the classic works of Saito and Kawai, the sulfide capacity and sulfur partition ratio were retrieved from the works of Taniguchi et al., and the slag density was retrieved from earlier experimental results of the present authors. The slag density was obtained from earlier experimental results from the present group. The Henrian activity coefficients were retrieved from literature. Subsequent to the present work, the design of experiments and measurements carried out using the proposed methodology and the results obtained are presented as the second article on this subject.

  6. Effect of High Cooling Rates on the Mineralogy and Hydraulic Properties of Stainless Steel Slags

    Science.gov (United States)

    Kriskova, Lubica; Pontikes, Yiannis; Pandelaers, Lieven; Cizer, Özlem; Jones, Peter Tom; Van Balen, Koen; Blanpain, Bart

    2013-10-01

    This article investigates the effect of chemical composition and cooling rate during solidification on the mineralogy and hydraulic properties of synthetic stainless steel slags. Three synthetic slags, covering the range of typical chemical composition in industrial practice, were subjected to high cooling rates, by melt spinning granulation or quenching in water, and to low cooling rates, by cooling inside the furnace. Both methods of rapid cooling led to volumetrically stable slags unlike the slow cooling which resulted in a powder-like material. Stabilized slags consisted predominantly of lamellar β-dicalcium silicate ( β-C2S) and Mg, Ca-silicates (merwinite and bredigite); the latter form the matrix at low basicity and are segregated along the C2S grain boundaries at high basicities. Slowly cooled slags consist of the γ-C2S polymorph instead of the β-C2S and of less Mg, Ca-silicates. Isothermal conduction calorimetry and thermogravimetric analysis indicate the occurrence of hydration reactions in the stabilized slags after mixing with water, while calcium silicate hydrates (C-S-H) of typical acicular morphology are identified by SEM. The present results demonstrate that the application of high cooling rates can result in a stable, environmental-friendly, hydraulic binder from stainless steel slags, rich in β-C2S, without the necessity of introducing any additions to arrest the β polymorph.

  7. The Analysis of the Chloride and Fluoride Influences on the Reducer Refinement Processes (Carbo-N-Ox Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    A. W. Bydałek

    2013-07-01

    Full Text Available Slag refining slag with west materials was analysed used the DTA methods. In the paper a method of determining the reduction capability, with the Carbo-N-Ox method, of slag solutions was used. Some relations between the stimulators in the environment - slag - metal system allow to initiate mass exchange reactions in the process of slag refining.The presented in work course of behaviour permits on choice of basic composition of slaglite, the of necessary components stimulating quantities, as well as on accomplishment of opinion of ability refinement. The worked out programme Slag-Prop, after introduction of data with experiment, it allows on next corrections in composition of proposed mixtures also, should be put on properly elaborated factors of multistage reaction with essential usage of suitable stimulators.

  8. Other Oxides Pre-removed from Bangka Tin Slag to Produce a High Grade Tantalum and Niobium Oxides Concentrate

    Science.gov (United States)

    Permana, S.; Soedarsono, J. W.; Rustandi, A.; Maksum, A.

    2016-05-01

    Indonesia, as the second largest tin producer in the world, has a byproduct from the production of tin. This byproduct is in the forms of tin slag containing tantalum pentoxide (Ta2O5) and niobium pentoxide (Nb2O5). This study focuses on the recovery of tantalum pentoxide and niobium pentoxide from the tin slag. In the process, one part of the tin slag sample was sieved only (BTS), and the other was roasted at 900°C, water quenched and then sieved (BTS-RQS). Samples BTS and BTS-RQS were characterized by thermo gravimetric analysis (TGA) and X-ray flourence (XRF). One part of BTS-RQS sample was dissolved in hydrofluoric acid (HF) and the other was dissolved in hydrochloric acid (HCl), washed with distilled water, then dissolved into sodium hydroxide (NaOH). Each sample was characterized by using XRF. The BTS sample produced the highest recovery of 0.3807 and 0.6978% for Ta2O5 and Nb2O5, respectively, from the particle size of -1.00+0.71 and a fraction of 47.29%, while BTS-RQS produced the highest recovery of 0.3931 and 0.8994% for Ta2O5 and Nb2O5, respectively, on the particle size of -0.71+0350 and a fraction of 21%. BTS-RQS, dissolved with 8% hydro fluoride acid, yields tantalum pentoxide and niobium pentoxide with a ratio of 2.01 and 2.09, respectively. For the sample BTS-RQS dissolve first with 6M hydrochloric acid, washed with distilled water, then dissolved with sodium hydroxide 10M, the yield ratios are 1.60 and 1.84 for tantalum pentoxide and niobium pentoxide, respectively. In this study, it is found that the dissolution by using hydrofluoric acid 8% yields the best ratio.

  9. Investigations of Stabilization of Cr in Spinel Phase in Chromium-Containing Slags

    OpenAIRE

    Jelkina Albertsson, Galina

    2011-01-01

    The influence of basicity, heat treatment as well as different oxygen partial pressures on the phase relationships in the CaO-MgO-SiO2-Cr2O3 slags was studied with a view to control the precipitation of Cr-spinel in the slag phase. The equilibrium phases in CaO-MgO-SiO2-Cr2O3 slag system in the range on 1673-1873 K have been investigated under low oxygen partial pressure as well as in as air atmosphere. In low oxygen partial pressure experiments, a suitable mixture of CO and CO2 was used to c...

  10. EFFECTS OF BLAST-FURNACE SLAG ON NATURAL POZZOLAN-BASED GEOPOLYMER CEMENT

    OpenAIRE

    MAHSHAD YAZDANIPOUR; EBRAHIM NAJAFI KANI; ALI ALLAHVERDI

    2011-01-01

    A number of geopolymer cement mixes were designed and produced by alkali-activation of a pumice-type natural pozzolan. Effects of blast-furnace slag on basic engineering properties of the mixes were studied. Different engineering properties of the mixes such as setting times and 28-day compressive strength were studied at different amounts of blast-furnace slag, sodium oxide content, and water-to-cement ratio. The mix comprising of 5 wt.% blast-furnace slag and 8 wt.% Na2O with a water-to-dry...

  11. Influence of Environmental Factors on the Volume Change of Blended Cement Containing Steel Slag

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In the condition of 20 ℃, 5% sulfate liquor curing, standard tap water curing and 50% RH curing-three different curing environments, the volume change of steel slag blended cement influenced by environmental factors was studied. With steel slag addition 10%, 30%, 50%, from 90 days to 356 days, the relationship of shrinkage and three different curing environments is: dry curing environment>tap water curing environment>sulfate curing environment. But, the sample shrinkage in 28 days has much difference with the curing environment, which has no obvious orderliness. The different effects on blended cement containing steel slag in different environmental factors were analyzed using SEM.

  12. Evaluation of the slag attack resistance of high alumina refractory free cement castable

    International Nuclear Information System (INIS)

    The slag attack resistance is a very important property when the life time of refractory castable needs to be improved. The substitution of calcium aluminate cement by a free calcium hydraulic blinder has show a viable way to enhance the thermomechanical performance presented by these materials. At the present very few information is found regarding the slag attack of these free cement castable. In this study the slag attack resistance of high alumina castable with and without cement was evaluated by static test. The corroded region was analyzed by SEM and EDS. (author)

  13. Utilization of copper slag as a cementitious material in reactive powder concrete

    OpenAIRE

    Edwin, Romy Suryaningrat; De Schepper, Mieke; Gruyaert, Elke; De Belie, Nele

    2015-01-01

    This research studies the use of copper slag from a plant in Belgium as a cementitious material in reactive powder concrete (RPC). The quickly cooled granulated copper slag (QCS) was ground intensively using a planetary ball mill. A lower water-to-binder ratio of 0.18 was chosen for the RPC in this study. Various concrete and cement paste samples were produced with increasing copper slag contents from 0 to 20 wt% in steps of 5 wt%. Particle size distribution (PSD) and specific surface area (S...

  14. Utilization of steel melting electric arc furnace slag for development of vitreous ceramic tiles

    Indian Academy of Sciences (India)

    Ritwik Sarkar; Nar Singh; Swapan Kumar Das

    2010-06-01

    Steel melting through electric arc furnace route is gaining popularity due to its many advantages, but generates a new waste, electric arc furnace slag, which is getting accumulated and land/mine filling and road construction are the only utilization. This slag has been tried to be value added and utilized to develop vitreous ceramic tiles. Slag, to the extent of 30–40 wt% with other conventional raw materials, were used for the development in the temperature range 1100–1150°C. The fired products showed relatively higher density with shorter firing range and good strength properties. Microstructural and EDAX studies were also done to evaluate the developed products.

  15. Recovery of iron and manganese values from metallurgical slags by the oxidation route

    OpenAIRE

    Semykina, Anna

    2010-01-01

    In the modern practice, a sustainable development strategy in a domain of wasteutilization is shifting its focus from a general completeness of recycling to a morespecific attention to efficiently utilize elements in the wastes. This is well-illustrated bythe steelmaking slag industries. The major waste product from the steelmaking practiceis slag and its main constituents are: CaO, SiO2, Al2O3, MnO, FeO and so on. The mainfield of application for the steelmaking slags is civil engineering, e...

  16. Investigation into hydrogen distribution between metal and slag in electric smelting of stainless steel

    International Nuclear Information System (INIS)

    Procedures are proposed for determining hydrogen in slags and for calculating the ''quasi-equilibrium'' constant of distribution of hydrogen between the metal and the slag in electric smelting of stainless steel of the type 18-10. Under the conditions investigated there is a correlation between the hydrogen content in the metal and in the slag. On the basis of a comparison of the obtained value of the hydrogen distribution constant, which is equal to 4.14, with the data of industrial smelting, recommendations are proposed aimed at a further decrease in the gas content of the metal and at increasing the technical and economic characteristics of smelting

  17. Composite cements containing natural pozzolan and granulated blast furnace slag

    Directory of Open Access Journals (Sweden)

    Irassar, E. F.

    2006-09-01

    Full Text Available For reasons of market demand and Portland cement production,the manufacture of cements with two or more separately ground additions to produce customized cements is becoming common practice.When pozzolan or slag content in this type of cements is high, however, the initial strength of the resulting product may be adversely impacted. This problem can be minimized by activating one or both of the replacement materials. The present study analyzes the effect of Portland cement additions such as physically activated natural pozzolan(up to 20% and/or granulated blast furnace slag (up to 35% on mortar flexural and compressive strength. The results show that higher strength is attained in ternary than binary cements. Initially (2 and 7 days, the highest compressive strengths are reached by mortars with up to 13% natural pozzolan and 5% slag, whereas at later ages mortars with larger proportions of additions are found to perform best.Debido a las exigencias del mercado y de la producción de cemento Portland, es cada vez más frecuente la elaboración de cementos con dos o más adiciones a partir de la molienda separada de sus constituyentes, dando origen a la formulación de los cementos a medida.Cuando el contenido de adiciones es alto, la utilización de puzolana y escoria en este tipo de cementos presenta la peculiaridad de disminuir la resistencia inicial del cemento resultante. Sin embargo, si algunas o ambas adiciones se activan, este problema puede minimizarse. En este trabajo se analiza la influencia de la incorporación al cemento Portland de puzolana natural (hasta 20% activada físicamente y/o escoria granulada de alto horno (hasta 35% sobre la resistencia a flexión y a compresión de morteros. Los resultados indican que los cementos ternarios presentan un mejor comportamiento resistente que los cementos binarios. Las máximas resistencias a compresión en las primeras edades (2 y 7 díasse alcanzan con hasta 13% de puzolana natural y 5% de

  18. Multiphase Modeling of Bottom-Stirred Ladle for Prediction of Slag-Steel Interface and Estimation of Desulfurization Behavior

    Science.gov (United States)

    Singh, Umesh; Anapagaddi, Ravikiran; Mangal, Saurabh; Padmanabhan, Kuppuswamy Anantha; Singh, Amarendra Kumar

    2016-02-01

    Ladle furnace is a key unit in which various phenomena such as deoxidation, desulfurization, inclusion removal, and homogenization of alloy composition and temperature take place. Therefore, the processes present in the ladle play an important role in determining the quality of steel. Prediction of flow behavior of the phases present in the ladle furnace is needed to understand the phenomena that take place there and accordingly control the process parameters. In this study, first a mathematical model is developed to analyze the transient three-phase flow present. Argon gas bottom-stirred ladle with off-centered plugs has been used in this study. Volume of fluid method is used in a computational fluid dynamics (CFD) model to capture the behavior of slag, steel, and argon interfaces. The results are validated with data from literature. Eye opening and slag-steel interfacial area are calculated for different operating conditions and are compared with experimental and simulated results cited in literature. Desulfurization rate is then predicted using chemical kinetic equations, interfacial area, calculated from CFD model, and thermodynamic data, obtained from the Thermo-Calc software. Using the model, it is demonstrated that the double plug purging is more suitable than the single plug purging for the same level of total flow. The advantage is more distinct at higher flow rates as it leads higher interfacial area, needed for desulfurization and smaller eye openings (lower oxygen/nitrogen pickup).

  19. Multiphase Modeling of Bottom-Stirred Ladle for Prediction of Slag-Steel Interface and Estimation of Desulfurization Behavior

    Science.gov (United States)

    Singh, Umesh; Anapagaddi, Ravikiran; Mangal, Saurabh; Padmanabhan, Kuppuswamy Anantha; Singh, Amarendra Kumar

    2016-06-01

    Ladle furnace is a key unit in which various phenomena such as deoxidation, desulfurization, inclusion removal, and homogenization of alloy composition and temperature take place. Therefore, the processes present in the ladle play an important role in determining the quality of steel. Prediction of flow behavior of the phases present in the ladle furnace is needed to understand the phenomena that take place there and accordingly control the process parameters. In this study, first a mathematical model is developed to analyze the transient three-phase flow present. Argon gas bottom-stirred ladle with off-centered plugs has been used in this study. Volume of fluid method is used in a computational fluid dynamics (CFD) model to capture the behavior of slag, steel, and argon interfaces. The results are validated with data from literature. Eye opening and slag-steel interfacial area are calculated for different operating conditions and are compared with experimental and simulated results cited in literature. Desulfurization rate is then predicted using chemical kinetic equations, interfacial area, calculated from CFD model, and thermodynamic data, obtained from the Thermo-Calc software. Using the model, it is demonstrated that the double plug purging is more suitable than the single plug purging for the same level of total flow. The advantage is more distinct at higher flow rates as it leads higher interfacial area, needed for desulfurization and smaller eye openings (lower oxygen/nitrogen pickup).

  20. Influence of slag chemistry on the hydration of alkali-activated blast-furnace slag — Part II: Effect of Al2O3

    International Nuclear Information System (INIS)

    The hydration and microstructural evolution of three alkali activated slags (AAS) with Al2O3 contents between 7 and 17% wt.% have been investigated. The slags were hydrated in the presence of two different alkaline activators, NaOH and Na2SiO3·5H2O. The formation of C(-A)–S–H and hydrotalcite was observed in all samples by X-ray diffraction, thermal analysis and scanning electron microscopy. Higher Al2O3 content of the slag decreased the Mg/Al ratio of hydrotalcite, increased the Al incorporation in the C(-A)-S-H and led to the formation of strätlingite. Increasing Al2O3 content of the slag slowed down the early hydration and a lower compressive strength during the first days was observed. At 28 days and longer, no significant effects of slag Al2O3 content on the degree of hydration, the volume of the hydrates, the coarse porosity or on the compressive strengths were observed.

  1. Greener durable concretes through geopolymerisation of blast furnace slag

    Science.gov (United States)

    Rajamane, N. P.; Nataraja, M. C.; Jeyalakshmi, R.; Nithiyanantham, S.

    2015-05-01

    The eco-friendliness of concrete is quantified by parameters such as ‘embodied energy’ (EE) and ‘embodied CO2 emission’ (ECO2e), besides duration of designed ‘service life’. It may be noted that ECO2e is also referred as carbon footprint (CF) in the literature. Geopolymer (GP) is an inorganic polymeric gel, a type of amorphous alumino-silicate product, which can be synthesised by polycondensation reactions. The concrete reported in this paper was prepared using industrial wastes in the form of blast furnace slag, fly ash as geopolymeric source materials and sodium silicate and sodium hydroxide as activators. Many mechanical properties such as compressive strength, chloride diffusion, steel corrosion, rapid chloride permeability test and rapid migration test are compared with Portland cement.

  2. Improvement of the high temperature slagging incineration system

    International Nuclear Information System (INIS)

    The objective of this paper is to describe the High Temperature Slagging Incinerator (HTSI) application study to reduce the volume of low level dry active waste (DAW) generated at nuclear power stations in Japan. The system, originally developed by SCK/CEN in Belgium, is being practically applied for the treatment of radioactive waste in Europe. JGC has been conducting the R and D work with a view to improving overall performance of the system and enhancing its safety and reliability. The performance tests of a pilot plant with a design capacity of 100 kg/hr revealed a number of positive attributes. It also ensures stable products which can be readily solidified when necessary for disposal

  3. Structural evolution of an alkali sulfate activated slag cement

    Science.gov (United States)

    Mobasher, Neda; Bernal, Susan A.; Provis, John L.

    2016-01-01

    In this study, the effect of sodium sulfate content and curing duration (from fresh paste up to 18 months) on the binder structure of sodium sulfate activated slag cements was evaluated. Isothermal calorimetry results showed an induction period spanning the first three days after mixing, followed by an acceleration-deceleration peak corresponding to the formation of bulk reaction products. Ettringite, a calcium aluminium silicate hydrate (C-A-S-H) phase, and a hydrotalcite-like Mg-Al layered double hydroxide have been identified as the main reaction products, independent of the Na2SO4 dose. No changes in the phase assemblage were detected in the samples with curing from 1 month up to 18 months, indicating a stable binder structure. The most significant changes upon curing at advanced ages observed were growth of the AFt phase and an increase in silicate chain length in the C-A-S-H, resulting in higher strength.

  4. PRODUCTION OF PAVING BLOCK AND KERB INCORPORATING BLASTFURNACE SLAG

    Directory of Open Access Journals (Sweden)

    İsa YÜKSEL

    2007-02-01

    Full Text Available This paper presents results of an experimental study about partial substitution of granulated blast-furnace slag (GBFS as fine aggregate in production of concrete paving blocks and kerbs. GBFS is replaced sand for different GBFS/sand ratios in concrete during production of kerb and paving block specimens. Some tests orienting towards strength and durability were applied on these specimens including control specimens that are produced with normal concrete. Then, the results of tested properties of GBFS-replaced specimens and control specimens were compared. GBFS decreases the compressive strength of paving blocks and kerbs according to the results. However, some durability properties which are more important than strength for these elements are improved with GBFS replacement. The most improved property was abrasion resistance. It is concluded that it is feasible to use GBFS in paving block and kerb production with an optimum replacement ratio for these specimens.

  5. Acid neutralisation capacity of accelerated carbonated stainless steel slag.

    Science.gov (United States)

    Johnson, D C; MacLeod, C L; Hills, C D

    2003-05-01

    The acid neutralisation capacity test is widely used to assess the long-term performance of waste materials prior to disposal. Samples of fixed mass are exposed to increasing additions of nitric add in sealed containers and the resultant pH is plotted as a titration curve. In this work, the add neutralisation capacity test was used in the assessment of an accelerated carbonated stainless steel slag. Difficulties arose in applying the test procedure to this material. This was largely because of the raised pressure from significant volumes of released carbon dioxide trapped in the sealed sample containers, causing an alteration to leachate pH values. Consequently, the add neutralisation capacity test was modified to enable testing of samples in equilibrium with the atmosphere. No adverse effects on the results from testing of a carbonate free material were recorded. PMID:12803247

  6. Deoxidation Limits of Titanium Alloys during Pressure Electro Slag Remelting

    Science.gov (United States)

    Bartosinski, M.; Hassan-Pour, S.; Friedrich, B.; Ratiev, S.; Ryabtsev, A.

    2016-07-01

    This paper focuses on deoxidation of titanium alloys produced by aluminothermic reduction (ATR) and subsequent homogenizing and alloying by vacuum induction melting (VIM). The main goal of the performed research work is to outline the deoxidation limit during pressure electro slag remelting (PESR) of the described material. To obtain electrodes for deoxidation, a Ti-24Al-16V masteralloy was produced by ATR and afterwards melted in a 0.5 litre calcium- zirconate (lab scale) or 14 litres high purity calcia (pilot scale) crucibles with continuous addition of Ti-sponge after reaching liquid state in order to obtain a final Ti-6Al-4V alloy. During melting, in both cases evaporation of calcium was noticed. The cast ingots were analysed for oxygen using inert gas fusion method, matrix and alloying elements were analysed by XRF. Results show oxygen levels between 0.5 and 0.95 wt.-% for the ingots which were melted in calcium-zirconate crucibles and approx. 1 - 1.2 wt.-% for the material produced by utilization of calcia crucibles. The subsequent deoxidation was carried out in lab and pilot scale electroslag remelting furnaces using a commercially pure calcium fluoride slag and metallic calcium as deoxidation agent. It could be shown, that deoxidation of the highly contaminated material is possible applying this method to a certain limit. Pilot scale trials showed a reduction of oxygen contents by 1500 - 3500 ppm. Oxygen levels in lab scale trials showed weaker deoxidation effects. In order to describe the achieved deoxidation effects in a quantitative way, the analyzed oxygen contents of the obtained ingots are compared with calculated data resulting from a mathematical kinetic model. The modelled datasets are in good agreement with experimental oxygen values.

  7. Use of copper slag in the manufacture of Portland cement

    Directory of Open Access Journals (Sweden)

    Aquilar Elguézabal, A.

    2006-03-01

    Full Text Available Given its chemical and mineralogical characteristics, copper slag, a solid industrial by-product, may serve as a partial substitute for silica and hematite in raw mixes used to manufacture Portland cement clinker. The benefits of such substitution include lower production costs and energy savings. The effect of slag-containing raw mixes on the reactivity of the CaO-Si02-Al203-Fe203 system was studied at three temperatures (1,350, 1,400 and 1,450ºC. Four mixes were used: M-1 and M-2 prepared with conventional prime materials and M-3 and M-4, in which ignimbrite and hematite were substituted for slag. In M-3 the slag replaced 45.54% of the ignimbrite and 100% of the hematite, and in M-4 100% of the mineral iron. The samples were clinkerized at 1,350, 1,400 and 1,450ºC. At 1,400ºC, clinker M-3 was found to have 10.7% less free lime than M-1, while the level in M-4 it was 15.93% lower than in M-2. The presence of the main clinker phases was confirmed by X-ray diffraction, which also showed that adding slag during c/inker manufacture slightly improves raw mix burnability without generating new unwanted phases. Consequently, recovery in cement kilns would appear to be an economically and environmentally feasible alternative to coprocessing such waste, although the industrial use of slag depends on its heavy metal content.En acuerdo con las características químicas y mineralógicas de la escoria de cobre, este residuo sólido industrial puede ser utilizado en el proceso de fabricación de clínker Portland como sustituto parcial de los minerales de sílice y hematita en la formación de mezclas crudas cuyos beneficios serían: disminución de los costos de producción de mezclas crudas y del consumo calorífico. El efecto de la adición de la escoria en las mezclas crudas sobre la reactividad del sistema CaO-Si02-Al203-Fe20 3 se estudió en tres niveles de temperatura (1.350, 1.400 Y 1.450ºC. Se trabajó con cuatro mezclas crudas, M-1 y M

  8. Anisotropy of Expansion Coefficient and Slag Resistance of Spinel Carbon Bricks

    Institute of Scientific and Technical Information of China (English)

    YANG Ding'ao; YUAN Shouqian; JIANG Mingxue; DONG Sunzhen; ZHAO Zijian

    2006-01-01

    Effects of the pressure direction on the thermal expansion and slag corrosion resistance were investigated and anisotropic microstructures of flaky graphite in spinel carbon bricks were examined. The experimental results show that slag corrosion velocities in the direction parallel to the pressure direction display a decrease of 34% compared to those in the vertical direction. Meantime, the linear expansion coefficient in the direction parallel to the pressure direction is 2.45 times as large as that in the vertical pressure direction. Slag corrosion velocities of spinel carbon bricks soaked in the AOD melting slag display a 46%-47% decrease compared to those of magnesia carbon bricks. The microstructure observation shows that spinel carbon bricks have a high degree of preferred orientation.

  9. Corrosion Resistance of MgO-C Based Refractory to Slag Containing Titania

    Institute of Scientific and Technical Information of China (English)

    LIU Qing-cai; SUN Ya-li; DU Yun-gui; CHEN Deng-fu

    2004-01-01

    The interaction between the slag containing titanium oxides (TiO2 of 2.0 %-20.0 %) and a MgO-C based refractory was investigated by immersion test. The relationship between TiO2 content in slag and corrosion rate of the refractory was studied. The microstructure and compositions of the corroded refractory were analyzed by SEM and X-ray diffraction. The corrosion mechanism of MgO-C based refractory in the slag containing titanium was proposed, and the effects of TiO2 content, slag basicity (ωCaO/ωSiO2) and temperature in molten bath on the corrosion rate of the refractory were obtained.

  10. Study on Microstructure and Slag Corrosion Mechanism of High Chrome Bricks for Gasifier

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Research was focused on slag corrosion mechanism of high chrome bricks used for different types of gasifier by comparing the structure of high chrome bricks for petroleum coke gasifier and water-coal slurry gasifier with slag corroded testing brick and water coal slurry gasifier through Scanning Electron Microscope (SEM) examination and X-ray diffraction. Results show that for high chrome brick used for petroleum coke gasifier, corrosion is mainly caused by Cr2O3 in the brick and V2O5 in molten slag and liquid phase generation at low temperature; for high chrome brick used for water-coal slurry gasifier, corrosion is caused by dissolution of Cr2O3 in molten slag and corrosion of ZrO2. For LIRR-HK95 brick, it performs better petroleum coke corrosion resistance than the others due to the optimal composition and structure.

  11. Characterization Report on Sand, Slag, and Crucible Residues and on Fluoride Residues

    Energy Technology Data Exchange (ETDEWEB)

    Murray, A.M.

    1999-02-10

    This paper reports on the chemical characterization of the sand, slag, and crucible (SS and C) residues and the fluoride residues that may be shipped from the Rocky Flats Environmental Technology Site (RFETS) to Savannah River Site (SRS).

  12. Short review on the origin and countermeasure of biomass slagging in grate furnace

    Directory of Open Access Journals (Sweden)

    Yiming eZhu

    2014-02-01

    Full Text Available Given the increasing demand for energy consumption, biomass has been more and more important as a new type of clean renewable energy source. Biomass direct firing is the most mature and promising utilization method to date, while it allows a timely solution to slagging problems. Alkali metal elements in the biomass fuel and the ash fusion behavior, as the two major origins contributing to slagging during biomass combustion, are analyzed in this paper. The slag presents various layered structures affected by the different compositions of ash particles. Besides, the high-temperature molten material which provides a supporting effect on the skeletal structure in biomass ash was proposed to evaluate the ash fusion characteristics. In addition, numerous solutions to biomass slagging, such as additives, fuel pretreatment and biomass co-firing, were also discussed.

  13. Efficiency of open-hearth slag under different levels of nitrogen nutrition

    International Nuclear Information System (INIS)

    Field and vegetational experiments have been carried out in the turf-podsolic soil in 1974-1977. Efficiency of open-hearth slag from Izhevsk metallurgical plant depends on the level of nitrogen nutrition. The greatest addition from the slag is received at the elevated level of nitrogen nutrition. The maximum total addition for 3 years resulting from the use of slag in the field experiment constituted 54.5 double centner forage units which is higher than the addition resulting from lime by 52.7 %. Besides, the slag produced positive effect upon the balance of the labelled 15N nitrogen in fertilizer: coefficient of the use of nitrogen in fertilizer during 2 years in the average increased by 7.1 and 11.2 % according to the nitrogen background of 230 and 460 mg/vessel

  14. Elementary composition of the siderurgy slag by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    The slag has been applied to the ground to neutralize its acidity, in similar way to the calcareous rock, contributing in the agriculture as corrective of the acidity alone it and source of nutrients for the plants. However, the alternative for the agricultural slag exploitation is related to metal texts heavy gifts in the slag. The objective of the present work was to survey of the chemical composition of trashes generated in blast high-oven, steel, oven of pan and fertilizers that had used in its manufacture slag of siderurgy for the technique of instrumental neutron activation analysis. The results had evidenced the existence of high variations in the elements Ce, Cr, In, K, Sb and Zn in the distinct analyzed samples. (author)

  15. Improving the behavior of body roads by the use of gravel-slag mixture

    Science.gov (United States)

    Hadinane, Hocine; Oucief, Hocine; Merzoud, Mouloud

    2016-07-01

    The accumulation of wastes industrial stemming of the iron and steel industry has influenced negatively the environment. The adopted policy had for mission to eliminate these undesirable wastes by recycling them by their utilization in adequate areas. The objective of this work is to study the mechanical behavior of a gravel-slag based on crystallized and granulated slag, activated by lime. One will be interested in the study of resistance to punching and the bearing ratio of this slag through Proctor tests, CBR and by compression, tensile tests, for use in the layers of pavement (Foundation and base layers). The obtained result on gravel-slag show considerable performances, compared with natural aggregates point of resistance and thickness of the layers. Its utilization in the road area has allowed therefore the recycling these industrial wastes, to decrease the pollution, to use a minimum noble product requiring important exploitation energy and an economy on layers of surface realized with costly materials (bituminous concrete).

  16. Applicability of mass action law to sulphur distribution between slag melts and liquid iron

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    According to the mass action law and the coexistence theory of slag structure, the calculating models of mass action concentration for CaO-MgO-FeO-Fe2O3-SiO2, CaO-MgO-MnO-FeO-Fe2O3-P2O5-SiO2 and CaO-MgO-MnO-FeO-Fe2O3-Al2O3-P2O5-SiO2 slag melts are formulated and sulphur distribution between the slag melts and liquid iron is treated. It is found that CaO, MnO and FeO promote desulphurization, while MgO is detrimental to desulphurization. In addition, the sulphur distribution coefficients between the slag melts and liquid iron are presented.

  17. Characterization Report on Sand, Slag, and Crucible Residues and on Fluoride Residues

    International Nuclear Information System (INIS)

    This paper reports on the chemical characterization of the sand, slag, and crucible (SS and C) residues and the fluoride residues that may be shipped from the Rocky Flats Environmental Technology Site (RFETS) to Savannah River Site (SRS)

  18. On the Heat Flux Vector and Thermal Conductivity of Slags: A Brief Review

    Directory of Open Access Journals (Sweden)

    Mehrdad Massoudi

    2016-01-01

    Full Text Available The viscosity and the thermal conductivity of slag are among two of the most important material properties that need to be studied. In this paper we review the existing theoretical and experimental correlations for the thermal conductivity of slag. However, since, in general, slag behaves as a non-linear fluid, it is the heat flux vector which must be studied. Both explicit and implicit approaches are discussed and suggestions about the form of the heat flux vector and the thermal conductivity and their dependence on shear rate, porosity, deformation, etc. are provided. The discussion of the constitutive modeling of the heat flux vector for slag is from a theoretical perspective.

  19. A study on anticorrosion effect in high-performance concrete by the pozzolanic reaction of slag

    International Nuclear Information System (INIS)

    The study examines the pozzolanic reaction brought by the addition of slag to the cement paste using the synchrotron radiation accelerator (SRA), the mercury intrusion porosimetry (MIP), and scanning electron microstructural analysis. The anticorrosion effect in high-performance concrete with and without slag added is also assessed by its electrical resistivity and permeability. Results show that pozzolanic reaction due to the addition of slag can decrease the amount of calcium hydroxide, reduce the volume of capillary pores (Pc), and lower its permeability, thus making the concrete more compact and durable. As evidenced by the enhanced electrical resistivity and reduced permeability, the addition of slag to high-performance concrete can indeed strength the anticorrosion effect

  20. Formation of spinel inclusions in molten stainless steel under Al deoxidation with slags; Slag kyozonka no Al datsusan katei ni okeru stainless yokochu spinel kaizaibutsu no seisei

    Energy Technology Data Exchange (ETDEWEB)

    Nishi, T.; Shinme, K. [Sumitomo Metal Industries, Ltd., Osaka (Japan)

    1998-12-01

    Morphology change of inclusions were experimentally investigated under Al deoxidation of molten stainless steel with CaO-SiO{sub 2}-Al{sub 2}O{sub 3}-MgO slags in order to clarify the morphology control factor of inclusions. 15kg of molten 18mass%Cr-8mass%Ni stainless steels were deoxidized by aluminum at 1873K, and the samples were taken at intervals to observe the inclusions by SEM and EDS. As the results, MgO contents of alumina type inclusions were gradually increased with time and the maximum contents were affected by a CaO/SiO{sub 2} ratio in slags. The formation of MgO-Al{sub 2}O{sub 3} spine type inclusions were also observed in case of high CaO/SiO{sub 2} ratio. The origin of Mg in inclusions was presumed to be deformation of MgO in slags. (author)

  1. Effect of fillers Granulated slag on the durability of HPC in marine environment

    OpenAIRE

    Tebbal Nadia; El abidine Rahmouni Zine; Djendi Zoubir

    2014-01-01

    The combined effect of fillers of silica fume and blast furnace slag on the durability of high performance concretes was studied .The storage media are: seawater and tap water as reference. This work focuses on the effect of the incorporation of different amounts of milk more silica fume on the mechanical strength of concretes with limestone cements and its influence on sustainability with respect to marine. The results show that the addition of quantity 10%slag and 5% silica fume offers the ...

  2. ANALYTICAL AND TECHNOLOGICAL EVALUATION OF ANCIENT LEAD SLAGS FROM LAVRION, ATTIKA, GREECE

    OpenAIRE

    Tsaimou, C.; Tsakiridis, P.E.; Oustadakis, P.

    2015-01-01

    The present research reports the chemical and mineralogical results of various archaeometallurgical lead slags from the Ari site at Lavrion, one of the largest ancient sites of Pb–Ag metallurgical activities in Greece, excavated by the School of Mining and Metallurgical Engineering of Greece, under the directorship of Prof. C. Tsaimou. Dating of the metallurgical slags was carried out using radiocarbon measurements, indicating the earliest phase of the Roman Empire. Chemical analysis, X...

  3. Effect of gas–slag interaction on valorisation of refuse derived fuel treated with plasma gasification

    OpenAIRE

    Yan, Pengcheng; Pandelaers, Lieven; Machiels, Lieven; Pontikes, Yiannis; Geysen, Daneel; Guo, Muxing; Blanpain, Bart

    2014-01-01

    During gasification of refuse derived fuel (RDF) to produce syngas in a system in which a melt is also produced, the gasified organic fraction of the RDF is in contact with the molten inorganic fraction, i.e. a slag. Examples of such systems are plasma gasifiers, in which crude syngas is further cracked in a plasma converter. Depending on the degree of gas–slag interaction, their compositions may vary and influence the valorisation potential of both resources. To evaluate the i...

  4. Characteristics and propierties of oil-well cements additioned with blast furnace slag

    OpenAIRE

    Sánchez, R.; Palacios, M.; Puertas, F.

    2011-01-01

    The present paper addresses the alkali activation of Portland cements containing blast furnace slag (20 and 30% of the cement by weight) with a view to the possible use of these materials in oil well construction. The hydration studies conducted showed that in cement/slag blends, the sodium silicate activating solution partially inhibited the dissolution of the silicate phases in the Portland cement, retarding cement hydration and reducing the precipitation of reaction products. D...

  5. Drying shrinkage of mortars with limestone filler and blast-furnace slag

    OpenAIRE

    Carrasco, M. F.; Bonavetti, V. L.; Irassar, E. F.

    2003-01-01

    During the 1990's the use of cements made with port land clinker and two mineral admixtures, called ternary or blended cements, has grown considerably. Nowadays, cements containing several combinations of fly ash and silica fume, blast-furnace slag and silica fume or blast-furnace slag and limestone filler are commonly used. There are numerous works on the influence of blended cements on the fresh state and mechanical properties of mortar and concrete, but the their deformations due to drying...

  6. Impact of Iron and Steel Slag on Crop Cultivation: A Review

    OpenAIRE

    Mir Syeda Yuhannatul Humaria

    2014-01-01

    This review paper addresses the issuesto analyze the impacts of Iron and Steel slag on crop cultivation. The use of steel slag in agriculture produces not only economic but also ecological advantages. The value of silicon (Si) application for rice (Oryzasativa) has been demonstrated when soil soluble Si is low.Impact of solid waste on crop cultivation depends on the availability and quantity of different constituents like PH, Ammonia, Nitrites, Nitrates, Permanganate Value (PV), Biochemical O...

  7. Advances in near-neutral salts activation of blast furnace slags

    OpenAIRE

    Bernal Lopez, S.

    2016-01-01

    The utilisation of near-neutral salts as activators to produce alkali-activated slag cements offers several technical advantages, including reduced alkalinity of the binders, minimising the risk associated with handling of highly alkaline materials, and better workability of the fresh paste compared to that of sodium silicate-activated slag cements. Despite these evident advantages, the delayed setting and slow early-age mechanical strength development of these cements have limited their adop...

  8. Studying the effect of thermal and acid exposure on alkali activated slag Geopolymer

    OpenAIRE

    Khater H.M.

    2014-01-01

    This article reports a study about thermal stability as well as acid resistance of geopolymer materials prepared from Ground Granulated Blast Furnace Slag (GGBFS), Air Cooled Slag (ACS), Silica fume (SF) and cement kiln dust (CKD) using 6% (weight) of equal mix from alkaline sodium hydroxide and sodium silicate activators. Study of addition of ACS, SF and CKD as partial replacement of GGBFS is investigated so as to improve the mechanical and microstructural properties of geopolymer mixes. Com...

  9. EAF C slag influence on physical and mechanical properties of concrete

    OpenAIRE

    Štokelj, Matevž

    2014-01-01

    The diploma thesis deals with the influence of the EAF slag C on physical-mechanical properties of concrete. Two concrete mixtures were designed according to the same recipe; however, two different aggregates with the same volume fraction were used. In the first mix the slag was applied and in the second one crushed limestone aggregate was incorporated. First the properties of concrete in the fresh state were tested: consistency of concrete by the slump method, content of air pores using pres...

  10. Effect of calcium silicate slag application on radium-226 concentrations in plant tissues

    International Nuclear Information System (INIS)

    A greenhouse pot experiment was conducted to determine if plants absorb Ra from slag applied to soil. Slag at rates equivalent to 0 and 22 mt/ha was mixed with Mountview silt loam (Typic Paleudults) limed to pH 5.8 and 7.2. Three clippings each of fescue (Festuca arundiancea Schreb.), and Swiss chard (Beta vulgaris L.), and one harvest of wheat (Triticum aestivum L.) for grain and straw were grown on separate series of treated soil, and plant samples were analyzed for radioactivity due to 226Ra uptake. Samples of sugarcane (Saccharum officinarum L.) forage and extracted juice from field experiments in Florida testing this slage as a Si source also were analyzed for radioactivity. Dry forage yields of fescue and wheat were not affected by slag applications, but those of Swiss chard were somewhat higher on slag-treated soil at pH 5.8. Wheat grain and straw yields were higher on soil at pH 7.2 than at pH 5.8 regardless of slag treatment. Uptake of 226Ra by fescue forage and wheat grain and straw was not affected by slag application. Concentrations of 226Ra were similar in forage and extracted juice from untreated sugarcane or that treated with slag at rates up to 5.6 mt/ha. These results suggest that plant uptake of radionuclides is negligible from calcium silicate slag applied at the recommended rates for liming acid soils or as a source of Si for sugarcane

  11. Study on Behaviour of Concrete Mix Replaceing Fine Aggregate With Steel Slag At Different Properties

    OpenAIRE

    P. Sateesh Kumar; VVS. Sarma

    2015-01-01

    This paper aims to study experimentally, the effect of partial replacement of fine aggregate by steel slag (ss), on the various strength and durability properties of concrete by using the mix designs .the optimum percentage of replacement of fine aggregate by steel slag is found. Workability of concrete gradually decreases, as the percentage of replacement increases which is found using slump test. Compressive strength, tensile strength, flexural strength and durability tests such...

  12. An environmental study of the use of steel slag aggregate in gabion cages

    OpenAIRE

    Richter, Tanya Brigitte

    2013-01-01

    The growing tendency of sustainable building and development is transforming the way in which construction projects are faced. These changes are saving the natural environment, as well as, minimising the quantity of industrial waste. In line with this initiative, the following project studies the potential recovery of Electric Arc Furnace Slag and its use as material fill in gabion cages. From a sustainability point of view, the recovery of steel slag is positive from all perspectives. (a) E...

  13. Resistance of Alkali-Activated Slag Concrete to Chloride-Induced Corrosion

    OpenAIRE

    Joon Woo Park; Ki Yong Ann; Chang-Geun Cho

    2015-01-01

    The corrosion resistance of steel in alkali-activated slag (AAS) mortar was evaluated by a monitoring of the galvanic current and half-cell potential with time against a chloride-contaminated environment. For chloride transport, rapid chloride penetration test was performed, and chloride binding capacity of AAS was evaluated at a given chloride. The mortar/paste specimens were manufactured with ground granulated blast-furnace slag, instead of Portland cement, and alkali activators were added ...

  14. Use of Steel Slag as Coarse Aggregate for the Production of Pervious Concrete

    OpenAIRE

    Georgia Vardaka; Kiriakos Thomaidis; Christos Leptokaridis; Stamatis Tsimas

    2014-01-01

    Pervious concrete is a type of concrete with significantly increased water permeability, ensuring increased rates of drainage of rainfall. The high porosity is achieved by removing a large percentage of fine aggregates from the mix. The present paper is an approach for the addition of steel slag as a substitute for coarse aggregates in pervious concrete. More specifically, three types of aggregates have been used: steel slag, construction and demolition wastes and conventional limestone aggre...

  15. Solidification of radioactive liquid waste - blast furnace slag as a binding agent

    International Nuclear Information System (INIS)

    During the reprocessing of spent Material Test Reactor (MTR) fuel elements from research reactor DIDO a radioactive waste solution is produced. Besides the radiotoxical elements, the waste solution contains aluminium from the cladding material of the spent fuel element and sodium hydroxide which is given to the acidic waste solution to reach a pH value between 12 and 13. After the neutralisation, the waste solution is solidified in a slag rich cement matrix. The final solidified product has to be assessed for a final disposal in a deep geological repository. One aspect of the assessment is related to intrinsic factors inherent to the solidified waste physical properties and the interaction between the binding agent and the waste solution. Another aspect of the safety assessment is related to the hydrolytic behaviour of the final cemented waste product under deep geological disposal conditions. The alkalinity of the waste solution acts as an activator for the hydration of the blast furnace slag. The rate of slag hydration decreases at late ages due to the formation of a denser microstructure of reaction products around the slag particles. The solidification of the waste solution with pure blast furnace slag and slag rich matrices leads to significant compressive strength. The effect is more marked for the waste solution cemented with only blast furnace slag. The solidification with blast furnace slag enables a physical immobilisation of the radiotoxical elements. In presence of MgCl2-rich salt brines, the solid waste matrice has no barrier function: the radiotoxical elements are released from the cement matrix within few months. Cs leaching behaviour shows no interaction with the cement matrix regardless of the pH in the surrounding aqueous phase. In contrast, a chemical interaction of Sr with the cement matrix can be identified for pH-value of leachant above 7. (orig.)

  16. Use of Phosphates to Reduce Slag Penetration in CR203-Based Refractories

    Energy Technology Data Exchange (ETDEWEB)

    Kwong, Kyei-Sing; Dogan, Cynthia P.; Bennett, James P.; Chinn, Richard E.; Petty, Arthur V.

    2004-11-09

    A high-chromium refractory material that provides improved resistance to coal slag penetration is presented. The refractory mixture comprises a blend of chromium oxide, aluminum oxide and phosphates. The refractory mixture may be blended with an aggregate and cured. In addition a phosphorus oxide may be blended with chromium oxide and aluminum oxide and additionally an aggregate. The refractory mixture reduces the rate of coal slag penetration into the surface of the cured refractory.

  17. Evaluation on chemical stability of lead blast furnace (LBF) and imperial smelting furnace (ISF) slags.

    Science.gov (United States)

    Yin, Nang-Htay; Sivry, Yann; Guyot, François; Lens, Piet N L; van Hullebusch, Eric D

    2016-09-15

    The leaching behavior of Pb and Zn from lead blast furnace (LBF) and imperial smelting furnace (ISF) slags sampled in the North of France was studied as a function of pHs and under two atmospheres (open air and nitrogen). The leaching of major elements from the slags was monitored as a function of pH (4, 5.5, 7, 8.5 and 10) under both atmospheres for different slag-water interaction times (1 day and 9 days). The leaching results were coupled with a geochemical model; Visual MINTEQ version 3.0, and a detailed morphological and mineralogical analysis was performed on the leached slags by scanning and transmission electron microscopy (SEM and TEM). Significant amounts of Ca, Fe and Zn were released under acidic conditions (pH 4) with a decrease towards the neutral to alkaline conditions (pH 7 and 10) for both LBF and ISF slags. On the other hand, Fe leachability was limited at neutral to alkaline pH for both slags. The concentrations of all elements increased gradually after 216 h compared to initial 24 h of leaching period. The presence of oxygen under open-air atmosphere not only enhanced oxidative weathering but also encouraged formation of secondary oxide and carbonate phases. Formation of carbonates and clay minerals was suggested by Visual MINTEQ which was further confirmed by SEM & TEM. The hydration and partial dissolution of hardystonite, as well as the destabilization of amorphous glassy matrix mainly contributed to the release of major elements, whereas the spinel related oxides were resistant against pH changes and atmospheres within the time frame concerned for both LBF and ISF slags. The total amount of Pb leached out at pH 7 under both atmospheres suggested that both LBF and ISF slags are prone to weathering even at neutral environmental conditions. PMID:27240207

  18. Modelling of the liquid slag behaviour in the continuous casting mould

    OpenAIRE

    Kountouriotis, Zacharias

    2011-01-01

    This work presents a fluid dynamics model of a continuous caster mould region, including the transient behaviour of the steel/slag interface. The research was carried out in collaboration with ArcelorMittal Research (AMR), based in Maizieres-les-Metz in France. The industrial objective of the thesis was to understand the factors affecting the transient behaviour of the liquid slag layer covering the steel and its interaction with the Submerged Entry Nozzle (SEN) jet supplying the steel from t...

  19. Effect of Slag Composition on Inclusions in Si-Deoxidized 18Cr-8Ni Stainless Steels

    Science.gov (United States)

    Ren, Ying; Zhang, Lifeng; Fang, Wen; Shao, Shijie; Yang, Jun; Mao, Weidong

    2016-04-01

    Laboratory experiments and thermodynamic calculation for the Si-deoxidized 18Cr-8Ni stainless steel with CaO-Al2O3-SiO2-CaF2-MgO-MnO slag were performed to investigate the effect of slag composition on inclusions in Si-deoxidized 18Cr-8Ni stainless steels. A high-basicity slag improved the cleanness of stainless steel, while a low basicity slag lowered the Al2O3 content in inclusions, lowering the melting temperature of inclusions and improving the deformability of inclusions. Approximately, 15 pct content of MgO in the initial slag was beneficial to reduce the corrosion of refractory and would not influence the composition of inclusions. The Al2O3 in slag should be lowered to a minimum to reduce the Al2O3 content in inclusions in Si-deoxidized 18Cr-8Ni stainless steel. The log X_{{{{Al}}_{ 2} {{O}}_{ 3} }}i + log X_{{MgO}}i - log X_{MnO}i - log X_{{{{SiO}}2 }}i of inclusions was expressed as a linear function of log a_{{{{Al}}_{ 2} {{O}}_{ 3} }}^{{s}} + log a_{{CaO}}^{{s}} - log a_{MnO}^{{s}} - log a_{{{{SiO}}2 }}^{{s}} of the slag, which was used to predict the composition of inclusions based on the activity of Al2O3, CaO, SiO2, and MnO in the slag. Moreover, the equilibrium curve of Al-O and the stability diagram of inclusions in Si-deoxidized 18Cr-8Ni stainless steel at 1873 K (1600 °C) were calculated.

  20. CONTACT STRENGTH OF MECHANOACTIVATED FINE CONCRETES FROM GRANULATED BLAST-FURNACE SLAGS

    Directory of Open Access Journals (Sweden)

    V. I. Bolshakov

    2014-10-01

    Full Text Available Purpose. Strengthening of fine concrete contact zone by mechanical processing of all components of the concrete mix in a mixer-activator and aggregate application with rough surface. Methodology. Rotary activator PC-06, developed by Scientific and Research Institute of Construction Technology, was used as a mixer-activator to achieve this purpose. Granulated blast furnace slag, having a more developed rough surface than sand, was used as fine aggregate. This apparatus provides intensive homogeneous mixing of concrete mix components, processing of raw materials (purification of their particles from contaminants, and mechanical destruction of granulated blast furnace slag surface layers and other components of the mix. Findings. During the preparation work, experimental research of new formations composition of fine concretes, using differential thermal and x-ray phase analysis methods, and physical-mechanical properties of fine concretes in accordance with the applicable standards of Ukraine, were carried out. It is established that the phase composition of new formations of fine concretes made from activated and non-activated mixes, is not changed. Their main difference is the size of generated effects and temperature intervals of occurrence of these peaks. Thus, in fine concretes made on the basis of the activated mixes, magnitude of effects is less, indicating a higher hydration degree of its components. Besides, TG curves of concrete specimens show that weight loss of gel calcium hydrosilicate of concrete from a mechanically activated mix is 0.5...0.7 % more than of concrete from a non-activated mix, which indicates a larger number of these formations in concrete from activated mixes. In general, concretes of different composition, made from a mix, processed in the mixer-activator, have higher mechanical strength. Originality. Ideas about the influence of mechanical activation of components of fine concrete mixes with forming humidity in a

  1. Iron blast furnace slag/hydrated lime sorbents for flue gas desulfurization.

    Science.gov (United States)

    Liu, Chiung-Fang; Shih, Shin-Min

    2004-08-15

    Sorbents prepared from iron blast furnace slag (BFS) and hydrated lime (HL) through the hydration process have been studied with the aim to evaluate their reactivities toward SO2 under the conditions prevailing in dry or semidry flue gas desulfurization processes. The BFS/HL sorbents, having large surface areas and pore volumes due to the formation of products of hydration, were highly reactive toward SO2, as compared with hydrated lime alone (0.24 in Ca utilization). The sorbent reactivity increased as the slurrying temperature and time increased and as the particle size of BFS decreased; the effects of the liquid/solid ratio and the sorbent drying conditions were negligible. The structural properties and the reactivity of sorbent were markedly affected by the BFS/HL ratio; the sorbent with 30/70 ratio had the highest 1 h utilization of Ca, 0.70, and SO2 capture, 0.45 g SO2/g sorbent. The reactivity of a sorbent was related to its initial specific surface area (Sg0) and molar content of Ca (M(-1)); the 1 h utilization of Ca increased almost linearly with increasing Sg0/M. The results of this study are useful to the preparation of BFS/HL sorbents with high reactivity for use in the dry and semidry processes to remove SO2 from the flue gas. PMID:15382877

  2. Study on immobilization of high level waste with alkali-activated slag cement

    International Nuclear Information System (INIS)

    A new solidification process using AASC (alkali-activated slag cement) to immobilize HLW (high level waste) is introduced in the article. The AASC incorporated with zeolite and condensed silica fume is used as the matrix of solidified product. High temperature and pressure are not necessary in this process. Under a confined volume the pressure caused by hydrolysis of still explosion to density the matrix of cement. It has high compressive strength, high density, low leachability and high resistance to heat. When the salt loading of HLW in the product is equal to 25 wt% the compressive strength of waste product is 65 ∼ 100 MPa, the porosity is less than 10%, the leachability for Cs is 10-5 g · d-1 and for Sr is 10-7 g · cm-2 · d-1. The performance of this kind cement is comparable with the vitrifying of HLW, but the process is simpler than vitrifying of waste method. The mechanism of the immobilization and the forms of nuclides in AASC waste product are also discussed

  3. Recycling ground granulated blast furnace slag as cold bonded artificial aggregate partially used in self-compacting concrete.

    Science.gov (United States)

    Gesoğlu, Mehmet; Güneyisi, Erhan; Mahmood, Swara Fuad; Öz, Hatice Öznur; Mermerdaş, Kasım

    2012-10-15

    Ground granulated blast furnace slag (GGBFS), a by-product from iron industry, was recycled as artificial coarse aggregate through cold bonding pelletization process. The artificial slag aggregates (ASA) replaced partially the natural coarse aggregates in production of self-compacting concrete (SCC). Moreover, as being one of the most widely used mineral admixtures in concrete industry, fly ash (FA) was incorporated as a part of total binder content to impart desired fluidity to SCCs. A total of six concrete mixtures having various ASA replacement levels (0%, 20%, 40%, 60%, and 100%) were designed with a water-to-binder (w/b) ratio of 0.32. Fresh properties of self-compacting concretes (SCC) were observed through slump flow time, flow diameter, V-funnel flow time, and L-box filling height ratio. Compressive strength of hardened SCCs was also determined at 28 days of curing. It was observed that increasing the replacement level of ASA resulted in decrease in the amount of superplasticizer to achieve a constant slump flow diameter. Moreover, passing ability and viscosity of SCC's enhanced with increasing the amount of ASA in the concrete. The maximum compressive strength was achieved for the SCC having 60% ASA replacement. PMID:22951223

  4. Effect of Boric Acid Concentration on Viscosity of Slag and Property of Weld Metal Obtained from Underwater Wet Welding

    Science.gov (United States)

    Guo, Ning; Guo, Wei; Xu, Changsheng; Du, Yongpeng; Feng, Jicai

    2015-06-01

    Underwater wet welding is a crucial repair and maintenance technology for nuclear plant. A boric acid environment raises a new challenge for the underwater welding maintenance of nuclear plant. This paper places emphasis on studying the influence of a boric acid environment in nuclear plant on the underwater welding process. Several groups of underwater wet welding experiments have been conducted in boric acid aqueous solution with different concentration (0-35000 ppm). The viscosity of the welding slag and the mechanical properties of welds, such as the hardness, strength, and elongation, have been studied. The results show that with increasing boric acid concentration, the viscosity of the slag decreases first and then increases at a lower temperature (less than 1441 °C). However, when the temperature is above 1480 °C, the differences between the viscosity measurements become less pronounced, and the viscosity tends to a constant value. The hardness and ductility of the joints can be enhanced significantly, and the maximum strength of the weld metal can be reached at 2300 ppm.

  5. Experimental determination of nonequilibrium transport parameters reflecting the competitive sorption between Cu and Pb in slag-sand column.

    Science.gov (United States)

    Chung, Jaeshik; Kim, Young-Jin; Lee, Gwanghun; Nam, Kyoungphile

    2016-07-01

    Competitive sorption and resulting nonequilibrium transport of Cu and Pb were investigated using slag as a primary sorbent. A series of estimation models were applied based on the equilibrium, and nonequilibrium sorption respectively, and finally calibrated by incorporating the experimentally determined batch kinetic data. When applied individually, the behavior of metals in slag-sand column were well predicted by both equilibrium and nonequilibrium models in CXTFIT code. However, coexisting Cu and Pb exhibited competition for sorption sites, generating an irregular breakthrough curves such as overshoot (higher concentration in effluent than the feed concentration) of Cu and corresponding earlier peak of Pb followed by gradual re-rising. Although two-site nonequilibrium model further considers coupled hydrochemical process, desorption of the Cu from competition made the model prediction inaccurate. However, the parameter estimation could be improved by incorporating the experimentally determined mass transfer rate, ωexp from batch kinetics. Based on the calibrated model, the fraction of instantaneous retardation, βexp of Pb decreased from 0.41 in the single system to 0.30 in the binary system, indicating the shift from equilibrium to nonequilibrium state, where which of Cu increased from 0.39 to 0.94, representing the shift towards equilibrium. The modified results were also compared with five-step sequential extraction data, confirming that the shift of particular metal fractions from the competition triggered the nonequilibrium transport. PMID:27060642

  6. Competitive adsorption of copper(II), cadmium(II), lead(II) and zinc(II) onto basic oxygen furnace slag

    Energy Technology Data Exchange (ETDEWEB)

    Xue Yongjie [School of Resource and Environment Science, Wuhan University, Hubei, Wuhan (China); Wuhan Kaidi Electric Power Environmental Protection Co. Ltd., Hubei, Wuhan (China)], E-mail: xueyj@mail.whut.edu.cn; Hou Haobo; Zhu Shujing [School of Resource and Environment Science, Wuhan University, Hubei, Wuhan (China)

    2009-02-15

    Polluted and contaminated water can often contain more than one heavy metal species. It is possible that the behavior of a particular metal species in a solution system will be affected by the presence of other metals. In this study, we have investigated the adsorption of Cd(II), Cu(II), Pb(II), and Zn(II) onto basic oxygen furnace slag (BOF slag) in single- and multi-element solution systems as a function of pH and concentration, in a background solution of 0.01 M NaNO{sub 3}. In adsorption edge experiments, the pH was varied from 2.0 to 13.0 with total metal concentration 0.84 mM in the single element system and 0.21 mM each of Cd(II), Cu(II), Pb(II), and Zn(II) in the multi-element system. The value of pH{sub 50} (the pH at which 50% adsorption occurs) was found to follow the sequence Zn > Cu > Pb > Cd in single-element systems, but Pb > Cu > Zn > Cd in the multi-element system. Adsorption isotherms at pH 6.0 in the multi-element systems showed that there is competition among various metals for adsorption sites on BOF slag. The adsorption and potentiometric titrations data for various slag-metal systems were modeled using an extended constant-capacitance surface complexation model that assumed an ion-exchange process below pH 6.5 and the formation of inner-sphere surface complexes at higher pH. Inner-sphere complexation was more dominant for the Cu(II), Pb(II) and Zn(II) systems.

  7. Competitive adsorption of copper(II), cadmium(II), lead(II) and zinc(II) onto basic oxygen furnace slag

    International Nuclear Information System (INIS)

    Polluted and contaminated water can often contain more than one heavy metal species. It is possible that the behavior of a particular metal species in a solution system will be affected by the presence of other metals. In this study, we have investigated the adsorption of Cd(II), Cu(II), Pb(II), and Zn(II) onto basic oxygen furnace slag (BOF slag) in single- and multi-element solution systems as a function of pH and concentration, in a background solution of 0.01 M NaNO3. In adsorption edge experiments, the pH was varied from 2.0 to 13.0 with total metal concentration 0.84 mM in the single element system and 0.21 mM each of Cd(II), Cu(II), Pb(II), and Zn(II) in the multi-element system. The value of pH50 (the pH at which 50% adsorption occurs) was found to follow the sequence Zn > Cu > Pb > Cd in single-element systems, but Pb > Cu > Zn > Cd in the multi-element system. Adsorption isotherms at pH 6.0 in the multi-element systems showed that there is competition among various metals for adsorption sites on BOF slag. The adsorption and potentiometric titrations data for various slag-metal systems were modeled using an extended constant-capacitance surface complexation model that assumed an ion-exchange process below pH 6.5 and the formation of inner-sphere surface complexes at higher pH. Inner-sphere complexation was more dominant for the Cu(II), Pb(II) and Zn(II) systems

  8. Task 3.15 -- Impacts of low-NOx combustion on fly ash and slagging. Semi-annual report, July 1--December 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Zygarlicke, C.J.; McCollor, D.P.

    1997-08-01

    With the advent of the Clean Air Act Amendments of 1990, the coal-fired power industry began a more accelerated move toward using low-NOx burner (LNB) technologies to reduce NOx emissions. Most LNBs incorporate less oxygen with the coal initially, creating a cooler and somewhat substoichiometric initial combustion zone, with additional oxygen added further on in the combustion process to complete char combustion. Another method used to achieve lower NOx emissions is to fire the coal substoichiometrically and add additional air through overfire air ports. Both of these methods create certain impacts on fireside performance that are different from conventional high-excess-air firing arrangements. Some of the impacts that have been noticed by the utility industry are higher levels of unburned carbon in the fly ash and bottom ash, increased boiler tube corrosion, higher particulate loadings on control devices, and changes in slagging in the main furnace. Work on the fundamental mechanisms of entrained ash and ash deposit formation during low-NOx combustion has been sparse. This project by the Energy and Environmental Research Center (EERC) focuses on the issues of entrained ash formation and slagging for low-NOx combustion systems in general. Time-resolved combustion tests under conventional and low-NOx conditions have been conducted to note particle-size formation and slagging deposition. The results from this work are yielding an increased understanding of the mechanisms of ash formation during low-NOx combustion along with methods for enhancing heat transfer and fly ash collectability. Specific objectives of this research project include (1) determining whether initial char and ash generated under low-NOx conditions have greater tendencies for slagging than conventionally generated ash and (2) determining the differences, if any, between particle size and composition for entrained ash generated under low-NOx and conventional combustion conditions.

  9. Synthesis of steel slag ceramics:chemical composition and crystalline phases of raw materials

    Institute of Scientific and Technical Information of China (English)

    Li-hua Zhao; Wei Wei; Hao Bai; Xu Zhang; Da-qiang Cang

    2015-01-01

    Two types of porcelain tiles with steel slag as the main raw material (steel slag ceramics) were synthesized based on the CaO–Al2O3–SiO2 and CaO–MgO–SiO2 systems, and their bending strengths up to 53.47 MPa and 99.84 MPa, respectively, were obtained. The presence of anorthite,α-quartz, magnetite, and pyroxene crystals (augite and diopside) in the steel slag ceramics were very different from the composition of traditional ceramics. X-ray diffraction (XRD) and electron probe X-ray microanalysis (EPMA) results illustrated that the addition of steel slag reduced the temperature of extensive liquid generation and further decreased the firing temperature. The considerable contents of glass-modifying oxide liquids with rather low viscosities at high temperature in the steel slag ceramic adobes promoted element diffusion and crystallization. The results of this study demonstrated a new approach for extensive and effective recycling of steel slag.

  10. Investigation of compressive strength of concrete with slag and silica fu

    International Nuclear Information System (INIS)

    Without doubt, concrete has special place in construction of different types of structures, and used as one of the most important materials in construction industry. Today, with development and modernization of human knowledge in construction industry, it is possible to reach high performance concrete. Mechanical properties and durability of high performance concrete is quite better than that of conventional concrete. In present, the use of supplementary cementitious materials, mainly silica fume, fly ash and blast furnace slag has become increasingly common for reasons of economy and technical benefits imparted by these materials. The aim of present research is investigation and comparison compressive strength of concrete specimens due to variation of water to cementitious materials ratio (W/C M), silica fume and slag percent and their proportions as cement replacement. Furthermore, it is intended to determine best combination of these materials with cement in concrete (optimum percent) to reach to maximum compressive strength. In the current study, specimens were made in 0.5,0.4 and 0.3 W/C M ratio contained 0,20,35 and 50 percent of slag as cement replacement, where in each slag replacement percent, 0, 5, 10 and 15 percent of of silica fume were used as cement replacement. Results of the current study show that the combination effect of slag and silica fume replacement in concrete leads to the maximum compressive strength in concrete; also there are some optimum percents for replacement of slag and silica fume to cement to get the best results

  11. Evaluation and Characterization of Plasma Sprayed Cu Slag-Al Composite Coatings on Metal Substrates

    Directory of Open Access Journals (Sweden)

    S. Mantry

    2013-01-01

    Full Text Available Copper slag is a waste product obtained during matte smelting and refining of copper. The present work explores the coating potential of copper slag by plasma spraying. This work shows that copper slag is eminently coatable. An attempt has been made in the present investigation to use the composites coatings of copper slag and Al powder in suitable combination on aluminium and mild steel substrates in order to improve the surface properties of these ductile metal-alloy substrates. When premixed with Al powder, the coating exhibits higher interfacial adhesion as compared to pure copper slag coatings. Maximum adhesion strengths of about 23 MPa and 21 MPa are recorded for the coatings of copper slag with 15 wt% of Al on aluminium and mild steel substrates, respectively. The input power to the plasma torch is found to affect the coating deposition efficiency and morphology of the coatings. It also suggests value addition of an industrial waste.

  12. Slag cement matrix for spent cationic resins arising from nuclear power plants

    International Nuclear Information System (INIS)

    Direct immobilisation of spent IX resins from nuclear power plants in slag cement matrix was investigated. The results showed that slag cement matrix can be satisfactorily used to immobilise cationic resins in K+ form arising from VVERs and mixed resins arising from PHWRs using vermiculite and bentonite admixtures. The optimum slag content of cement is 50 weight percent The cumulative fraction of 137Cesium leached and 137Cesium leach rate values for best slag cement matrix incorporating cationic resins in K+ form from VVER type reactor were 0.0623 and 0.000566 g/cm2/d with 140 days leaching. The cumulative fraction of 137Cesium leached and 137Cesium leach rate values for slag cement matrix incorporating mixed resins from PHWRs type reactors were 0.0705 and 0.0009 g/cm2/d for 95 days leaching. Contraction of swollen bentonite and IX resins while setting of cement and its subsequent curing decreased strength of pure slag cement matrix from 241 to 50 kg/cm2. (author)

  13. Slag cement matrix for immobilisation of spent organic ion exchange resins from nuclear power plants

    International Nuclear Information System (INIS)

    The spent IX resins from nuclear power reactors are highly active solid wastes generated during operations of water cooled nuclear power plants. Direct immobilisation of spent IX resins in slag cement matrix was investigated. Slag cement matrix formulations were optimised for mixed, K+ and borate resins by evaluating leaching characteristics, porosity, hydraulic conductivity etc. The 137cesium leaching characteristics of slag cement matrices developed in this study gave the average leach rates of the order of 10-4 g/cm2/d and leachability indices of 8.4 to 9.6. The 137cesium behaviour was in accordance with the porosity and hydraulic conductivity of matrix. The laboratory study revealed that these tests can be effectively used to shortlist cement matrix formulations for long term 137cesium leach tests. The results showed that slag cement matrix can be satisfactorily used to immobilise spent resins arising from PHWR and PWR/VVER type reactors. The selected formulations were successfully deployed to prepare full size (200 litre) slag cement matrix block incorporating 100 litres of mixed IX resins. The compressive strengths of core drilled samples were 64 to 118 kg/cm2 which satisfactorily meet the safety requirements. The study has shown that the slag cement matrix has potential to replace the polymer matrix making treatment of spent IX resins cost effective. (author)

  14. Disposal of High-Temperature Slags: A Review of Integration of Heat Recovery and Material Recycling

    Science.gov (United States)

    Sun, Yongqi; Zhang, Zuotai

    2016-05-01

    Nowadays with the continuous urbanization in China, the carbon emission and resource shortage have been serious issues, for which the disposal of blast furnace slags (BFS) and steel slags (SS) discharged from the metallurgical industry make up a significant strategy. The output of crude steel reached 823 Mt in China in 2014 and the thermal heat in these slags was equivalent to ~18 Mt of standard coal. Herein, the recent advances were systemically reviewed and analyzed, mainly from two respects, i.e., integration of heat recovery and material recycling and crystallization control of the slags. It was first found that for the heat recovery from BFS, the most intensively investigated physical method and chemical method were centrifugal granulation and gasification reaction, respectively. Furthermore, a two-step approach could contribute to a promising strategy for the treatment of slags, i.e., the liquid slags were first granulated into small particles, and then other further treatment was performed such as gasification reaction. With regard to SS, the effective disposal could be achieved using a selective crystallization and phase separation (SCPS) method, and moreover, the solid solution of 2CaO·SiO2 and the target phases could act as a promising enriched phase to extract the valuable elements.

  15. Simultaneous removal of Ni(II), As(III), and Sb(III) from spiked mine effluent with metakaolin and blast-furnace-slag geopolymers.

    Science.gov (United States)

    Luukkonen, Tero; Runtti, Hanna; Niskanen, Mikko; Tolonen, Emma-Tuulia; Sarkkinen, Minna; Kemppainen, Kimmo; Rämö, Jaakko; Lassi, Ulla

    2016-01-15

    The mining industry is a major contributor of various toxic metals and metalloids to the aquatic environment. Efficient and economical water treatment methods are therefore of paramount importance. The application of natural or low-cost sorbents has attracted a great deal of interest due to the simplicity of its process and its potential effectiveness. Geopolymers represent an emerging group of sorbents. In this study, blast-furnace-slag and metakaolin geopolymers and their raw materials were tested for simultaneous removal of Ni(II), As(III) and Sb(III) from spiked mine effluent. Blast-furnace-slag geopolymer proved to be the most efficient of the studied materials: the experimental maximum sorption capacities for Ni, As and, Sb were 3.74 mg/g, 0.52 mg/g, and 0.34 mg/g, respectively. Although the capacities were relatively low due to the difficult water matrix, 90-100% removal of Ni, As, and Sb was achieved when the dose of sorbent was increased appropriately. Removal kinetics fitted well with the pseudo-second-order model. Our results indicate that geopolymer technology could offer a simple and effective way to turn blast-furnace slag to an effective sorbent with a specific utilization prospect in the mining industry. PMID:26598283

  16. Influence of the Mold Current on the Electroslag Remelting Process

    Science.gov (United States)

    Hugo, Mathilde; Dussoubs, Bernard; Jardy, Alain; Escaffre, Jessica; Poisson, Henri

    2016-08-01

    The electroslag remelting process is widely used to produce high value-added alloys. The use of numerical simulation has proven to be a valuable way to improve its understanding. In collaboration with Aubert & Duval, the Institute Jean Lamour has developed a numerical transient model of the process. The consumable electrode is remelted within a mold assumed to be electrically insulated by the solidified slag skin. However, this assumption has been challenged by some recent studies: the solidified slag skin may actually allow a part of the melting current to reach the mold. In this paper, the evolution of our model, in order to take into account this possibility, is presented and discussed. Numerical results are compared with experimental data, while several sensitivity studies show the influence of some slag properties and operating parameters on the quality of the ingot. Even, a weakly conductive solidified slag skin at the inner surface of the mold may be responsible for a non-negligible amount of current circulating between the slag and crucible, which in turn modifies the fluid flow and heat transfer in the slag and ingot liquid pool. The fraction of current concerned depends mainly on the electrical conductivities of both the liquid and solidified slag.

  17. Repulsion forces of superplasticizers on ground granulated blast furnace slag in alkaline media, from AFM measurements to rheological properties

    OpenAIRE

    Palacios, M.; Bowen, P.; Kappl, M.; Butt, H. J.; Stuer, M; Pecharromán, C.; Aschauer, U.; Puertas, F.

    2012-01-01

    The electrostatic and steric repulsion induced by different superplasticizers on ground granulated blast furnace slag in alkaline media have been studied. The superplasticizers were sulfonated naphthalene, sulfonated melamine, vinyl copolymer, and polycarboxylate- based admixtures. With these superplasticizers the slag suspensions had negative zeta potentials, ranging from -3 to -10 mV. For the first time the adsorbed layer thicknesses for superplasticizers on slag using colloidal probe atomi...

  18. Repulsion forces of superplasticizers on ground granulated blast furnace slag in alkaline media, from AFM measurements to rheological properties

    OpenAIRE

    Palacios, M.; Kappl, M.; Stuer, M; Aschauer, U.; Bowen, P.; Butt, H. J.; Pecharromán, Carlos; Puertas, F.

    2012-01-01

    [EN]The electrostatic and steric repulsion induced by different superplasticizers on ground granulated blast furnace slag in alkaline media have been studied. The superplasticizers were sulfonated naphthalene, sulfonated melamine, vinyl copolymer, and polycarboxylate- based admixtures. With these superplasticizers the slag suspensions had negative zeta potentials, ranging from -3 to -10 mV. For the first time the adsorbed layer thicknesses for superplasticizers on slag...

  19. The characterisation, improvement and modelling aspects of Frost Salt Scaling of Cement-Based Materials with a High Slag Content

    OpenAIRE

    Copuroglu,O.

    2006-01-01

    Blast furnace slag cement concrete is used extensively in a number of countries. In comparison with OPC, it is particularly well known for its excellent performance in marine environments. One dis-advantage of slag cement is its vulnerability to scaling under the combined load of freezing-thawing and de-icing salts. The current investigation was triggered by positive observations regard-ing certain grinding agents used in slag cement production to improve frost salt scaling resistance. The in...

  20. Quantification of slag heap volumes and masses through the use of induced polarization : application to the Castel-Minier site

    OpenAIRE

    Florsch, Nicolas; Llubes, M.; Tereygeol, E.; A. Ghorbani; Roblet, P.

    2011-01-01

    When used for archaeological purposes, geophysical methods are often useful for the exploration, detection and mapping of archaeological remains. In the case of ancient metallurgical activities, slag accumulations form precious mineral records of these activities. Evaluating the volume of slag produced in such locations is an important issue, since it enables an estimate of the amount of metal produced in the smeltery. Unfortunately, slags themselves cannot be easily detected by DC electrical...

  1. Mechanical Properties and Eco-Efficiency of Steel Fiber Reinforced Alkali-Activated Slag Concrete

    Directory of Open Access Journals (Sweden)

    Sun-Woo Kim

    2015-10-01

    Full Text Available Conventional concrete production that uses ordinary Portland cement (OPC as a binder seems unsustainable due to its high energy consumption, natural resource exhaustion and huge carbon dioxide (CO2 emissions. To transform the conventional process of concrete production to a more sustainable process, the replacement of high energy-consumptive PC with new binders such as fly ash and alkali-activated slag (AAS from available industrial by-products has been recognized as an alternative. This paper investigates the effect of curing conditions and steel fiber inclusion on the compressive and flexural performance of AAS concrete with a specified compressive strength of 40 MPa to evaluate the feasibility of AAS concrete as an alternative to normal concrete for CO2 emission reduction in the concrete industry. Their performances are compared with reference concrete produced using OPC. The eco-efficiency of AAS use for concrete production was also evaluated by binder intensity and CO2 intensity based on the test results and literature data. Test results show that it is possible to produce AAS concrete with compressive and flexural performances comparable to conventional concrete. Wet-curing and steel fiber inclusion improve the mechanical performance of AAS concrete. Also, the utilization of AAS as a sustainable binder can lead to significant CO2 emissions reduction and resources and energy conservation in the concrete industry.

  2. Pb(II) removal from aqueous solution by a low-cost adsorbent dry desulfurization slag

    Science.gov (United States)

    Wu, Qiong; You, Ruirong; Clark, Malcolm; Yu, Yan

    2014-09-01

    A collectable and non-sintered material prepared as hollow cylindrical shaped pellet from dry desulfurization slag (FGD ash) and ordinary Portland cement (OPC) for wastewater treatments is tested. The characteristic results of powder X-ray diffraction (XRD) and infrared absorption spectroscopy (IR) show that -OH, CO32-, SO32- and SO42- are the possible functional groups responsible for Pb uptake. Adsorption data indicate that Pb removal is pH dependent and optimal at pH 6, with a very rapid initial removal that reaches equilibrium in about 90 min. A maximum removal of 99.2% is seen for 5 mg/L (pH of 6); higher initial Pb concentrations reduce overall removal efficiencies, but generate higher surface loadings. Adsorption process correlates well with both Langmuir and Freundlich models, although the Langmuir isotherm is more favored, providing a maximum adsorption capacity (Qm) of 130.2 mg/g (13 wt%). Pseudo-second order rate kinetic model best describes the Pb removal, and calculated RL values between 0 and 1, indicate a favored adsorption process that is chemisorption limited. SEM and EDAX analysis of the surface and fracture surface show that Pb occurs as surface precipitates and that Pb is not distributed to the inner core of the pellet. This study demonstrates that dry FGD ash could be successfully used for wastewater Pb removal.

  3. Investigations on phosphorus recovery and reuse as soil amendment from electric arc furnace slag filters.

    Science.gov (United States)

    Bird, Simon C; Drizo, Aleksandra

    2009-11-01

    Electric arc furnace (EAF) steel slag has been identified as an effective filter material for the removal of phosphorus (P) from both point and non-point sources. To determine the feasibility of land-applying P saturated EAF steel slag this study was undertaken to investigate (i) saturated EAF steel slag material's potential as a P fertilizer or soil amendment and (ii) P desorption and metals leachate from saturated EAF steel slag material to surface runoff. Medicago sativa (alfalfa) was planted in a nutrient depleted washed sand media. Phosphorus was added either as saturated EAF steel slag or as a standard commercial phosphate fertilizer in order to assess the plant availability of the P from saturated EAF steel slag. Four different P application levels were tested: a low (20 lbs acre furrow slice(-1) (5.5 g P m(-3))) two medium (40 and 60 lbs. acre f.s.(-1) (11 and 16.5 g P m(-3))) and a high (120 lbs. acre f.s.(-1) (33 g P m(-3))). The above-ground biomass of half of the plants was harvested after 5 weeks and the second half at 10 weeks. All treatments regardless of the P source used showed high rates of germination. At the first harvest period (5 weeks) significantly higher above-ground biomass (p fertilizer (TSP) than with EAF steel slag. However, by the second harvest (10 weeks) only the highest amendment rate of TSP showed a significantly higher amount of biomass (p slow release P source. In a second experiment, a rain simulator was used to assess desorption of DRP, TP and metals from a saturated and semi-saturated EAF steel slag. The results revealed that the total amounts of DRP and TP released to surface runoff from EAF steel slag were negligible when compared to the total quantities of P retained by this material. Overall the results from this study demonstrated that once the EAF steel slag filter reaches its saturation point, the material could be re-used as soil amendment for the slow release of bioavailable P with minimal risk for loss of P to

  4. Frit screening for Rocky Flats ash and sand, slag, and crucible vitrification

    International Nuclear Information System (INIS)

    Pacific Northwest National Laboratory (PNNL) is developing vitrified waste forms for plutonium-bearing ash and plutonium-bearing sand, slag, and crucible (SS ampersand C) materials from Rocky Flats. Waste forms are to meet product criteria (e.g., safeguard termination limits, storage criteria, and target plutonium loading) and processing constraints (e.g., upper temperature limits, processing time, and equipment compatibility). The target waste form for ash is an agglomerated product, while that for SS ampersand C is a fully encapsulated product. Laboratory scoping studies were conducted on glass formulations from six different glass families: (1) antimony vanadium phosphate, (2) iron vanadium phosphate, (3) tin zinc phosphate, (4) soda-lime silicate, (5) alkali borosilicate, and (6) alkali borate. Glass families were selected due to viscosity behavior in the temperature range of interest (< 800C). Scoping study tests included gradient furnace tests to determine processing range and sintering temperature, thermogravimetric analysis to determine weight loss as a function of temperature, and crucible tests to determine frit compositions tolerance to variations in processing temperature, waste loading, and waste type. The primary screening criterion for the selection of frits for future studies was processing temperature below 400C to minimize the potential for foaming in ash caused by the release of gases (main source of gas is combustion of carbon species) and to minimize processing cycle times. Based on this criterion, glass formulations from the tin zinc phosphate and alkali borosilicate families were selected for future variability testing. Variability testing will include final product evaluation, glass system tolerance to waste loading and composition variation, and identification of parameters impacting time/temperature profiles. Variability testing results will give a final frit formulation for ash and SS ampersand C, and identify key processing parameters

  5. Basicity for blast furnace-type slag containing B2O3 and high MgO

    Institute of Scientific and Technical Information of China (English)

    黄振奇; 蔡亚旻; 朱文非; 杨祖磐

    2003-01-01

    There is quite abundant resource of ludwigite ore in Liaoning Province of China. Content of MgO in the slag of pyrometallurgical separation of boron from iron is much higher than that in the ordinary slags. Through the equilibrium partition ratio of sulfur LS between the metal and the slag in an atmosphere of CO-N2, the acidic coefficients for B2O3 and the basic coefficients for MgO were estimated. The basic formulae were given for the blast furnace-type slag containing B2O3 and high MgO.

  6. Characterization of Iron and Steel Industry Slags to be Recycled under Ecological Aspects as a Recycling Concept for Waste Treatment

    International Nuclear Information System (INIS)

    The recycling and final disposal of different types of industrial waste play an important role in decreasing environmental pollution all over the world. Three different solid waste slags from steel industries situated in the Helwan area (Cairo-Egypt), namely blast furnace slags, oxygen converter slags arc furnace slags were studied. The morphology of the collected slag powders was examined using scanning electron microscopy (SEM). Surface characteristics of the slag powders were measured through nitrogen gas adsorption and application of the BET equation at 77 K. The thermal behaviour of the slag powders was studied with the help of differential thermal analysis (DTA) and thermogravimetry(TG)> Due to the presence of some changes in the DTA base lines, possibly as a result of phase transformations, X-ray diffraction was applied to identify these phases. The sintering behaviour of the compact slag powders after isostatic pressing was evaluated using dilatometry. The sintering and melting temperature of the studied samples were determined using heating microscopy. The effect of changing sintering temperature and of applying different isostatic pressures on the density and porosity of the slag powder compacts was investigated

  7. Hydroxyapatite crystallization from a highly concentrated phosphate solution using powdered converter slag as a seed material

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eung-Ho [School of Urban and Civil Engineering, Hongik University, Sangsu-dong 72-1, Mapo-gu, Seoul 121-791 (Korea, Republic of); Yim, Soo-Bin [School of Urban and Civil Engineering, Hongik University, Sangsu-dong 72-1, Mapo-gu, Seoul 121-791 (Korea, Republic of)]. E-mail: ysb9643@hotmail.com; Jung, Ho-Chan [School of Urban and Civil Engineering, Hongik University, Sangsu-dong 72-1, Mapo-gu, Seoul 121-791 (Korea, Republic of); Lee, Eok-Jae [TaeYoung Corporation, Kongdeok-dong, Mapo-gu, Seoul 121-020 (Korea, Republic of)

    2006-08-25

    A system for recovering phosphorus from membrane-filtrate from a sludge reduction process containing high phosphorus concentrations was developed. In this system, referred to as the completely mixed phosphorus crystallization reactor, powdered converter slag was used as a seed material. In a preliminary experiment, the optimal pH range for metastable crystallization of phosphorus from membrane-filtrate containing about 100 mg/L PO{sub 4}-P was found to be 6.6-7.0. The laboratory scale completely mixed phosphorus crystallization reactor, actually operated in pH range of 6.8-7.6 for influent 72.9 mg/L PO{sub 4}-P, achieved an average efficiency of phosphorus removal from the membrane-filtrate of 52.4% during a 30-day experiment. Mixed-liquor suspended solids (MLSS) measurements revealed that, out of 0.24 kg PO{sub 4}-P in the original membrane-filtrate fed into the reactor, 0.12 kg PO{sub 4}-P was recovered on the seed particles after 30 days. X-ray diffraction (XRD) pattern and Fourier transform infrared (FT-IR) spectra of the crystalline material deposited on the seed particles showed peaks consistent with hydroxyapatite. Scanning electron micrograph (SEM) images exhibited that finely distributed crystalline material was formed on the surfaces of seed particles. Energy dispersive X-ray spectroscopy (EDS) mapping analysis revealed that the molar composition ratio of Ca/P of the crystalline material was 1.84. The Ca/P molar ratio > 1.67 for crystalline substance might result from the presence of CaCO{sub 3} on the crystalline surfaces. A particle size distribution analysis showed that the average particle size increased from 22 {mu}m for the original converter slag seed particles, to 94 {mu}m after 30 days of phosphorus crystallization. Collectively, the present results suggest that the proposed phosphorus crystallization recovery system is an effective tool for recycling phosphorus from phosphate solution.

  8. Investigations of the surface tension of coal ash slags under gasification conditions; Untersuchungen zur Oberflaechenspannung von Kohleschlacken unter Vergasungsbedingungen

    Energy Technology Data Exchange (ETDEWEB)

    Melchior, Tobias

    2011-10-26

    In the context of CO{sub 2}-emission-induced global warming, greenhouse gases resulting from the production of electricity in coal-fired power plants gain increasing attention. One possible way to reduce such emissions is to gasify coal instead of burning it. The corresponding process is referred to as Integrated Gasification Combined Cycle and allows for the separation of CO{sub 2} before converting a synthesis gas into electrical energy. However, further improvements in efficiency and availability of this plant technology are needed to render the alternative generation of electricity sensible from an economic point of view. One corresponding approach introduces hot gas cleaning facilities to the gasification plant which guarantee a removal of slag particles from the synthesis gas at high temperatures. The development of such filters depends on the availability of data on the material properties of the coal ash slags to be withdrawn. In this respect, the surface tension is a relevant characteristic. Currently, the surface tension of real coal ash slags as well as of synthetic model systems was measured successfully by means of the sessile drop and the maximum bubble pressure method. With regard to the sessile drop technique, those experiments were conducted in a gasification-like atmosphere at temperatures of up to 1500 C. Furthermore, the pressure inside the experimental vessel was raised to 10 bar in order to allow for deriving the influence of this variable on the surface tension. In contrast, maximum bubble pressure trials were realised at atmospheric pressure while the gas atmosphere assured inert conditions. For performing sessile drop measurements, a corresponding apparatus was set up and is described in detail in this thesis. Three computer algorithms were employed to calculate surface tensions out of the photos of sessile drops and their individual performance was evaluated. A very good agreement between two of the codes was found while the third one

  9. Steel slag carbonation in a flow-through reactor system: the role of fluid-flux.

    Science.gov (United States)

    Berryman, Eleanor J; Williams-Jones, Anthony E; Migdisov, Artashes A

    2015-01-01

    Steel production is currently the largest industrial source of atmospheric CO2. As annual steel production continues to grow, the need for effective methods of reducing its carbon footprint increases correspondingly. The carbonation of the calcium-bearing phases in steel slag generated during basic oxygen furnace (BOF) steel production, in particular its major constituent, larnite {Ca2SiO4}, which is a structural analogue of olivine {(MgFe)2SiO4}, the main mineral subjected to natural carbonation in peridotites, offers the potential to offset some of these emissions. However, the controls on the nature and efficiency of steel slag carbonation are yet to be completely understood. Experiments were conducted exposing steel slag grains to a CO2-H2O mixture in both batch and flow-through reactors to investigate the impact of temperature, fluid flux, and reaction gradient on the dissolution and carbonation of steel slag. The results of these experiments show that dissolution and carbonation of BOF steel slag are more efficient in a flow-through reactor than in the batch reactors used in most previous studies. Moreover, they show that fluid flux needs to be optimized in addition to grain size, pressure, and temperature, in order to maximize the efficiency of carbonation. Based on these results, a two-stage reactor consisting of a high and a low fluid-flux chamber is proposed for CO2 sequestration by steel slag carbonation, allowing dissolution of the slag and precipitation of calcium carbonate to occur within a single flow-through system. PMID:25597686

  10. The Effect of Refining Slag and Refractory on Inclusion Transformation in Extra Low Oxygen Steels

    Science.gov (United States)

    Liu, Chunyang; Huang, Fuxiang; Wang, Xinhua

    2016-04-01

    MgO-based refractory and MgO bearing slag both have the potential to supply Mg or Ca to the molten steel and then prompt the inclusion transformation. In this paper, the effect of MgO-based refractory and MgO bearing slag on the spinel generation was investigated on laboratorial scale. The results indicated that refractory had a great contribution to MgO·Al2O3 spinel generation. Although refining slag was faster than MgO-C refractory and than MgO refractory in terms of Mg supply velocity, if the interaction area with the molten steel was taken into calculation, MgO-C and MgO refractory supplied more Mg into molten steel than refining slag during the same time. In addition, refining slag can not only supply Mg into the molten steel to form MgO in inclusions but also supply Ca to generate CaO bearing inclusions. The Al2O3 inclusions transformed through the Al2O3 → MgO·Al2O3 → CaO·MgO·Al2O3 routine and the reason why the Al2O3 inclusions degraded into MgO·Al2O3 rather than CaO·Al2O3 inclusions firstly was clarified. CaO and MgO in the slag can be both reduced at the slag-metal interface and then supply [Ca] and [Mg] into the steel melt. [Ca] activity was dramatically suppressed by the dissolved oxygen in the steel melt and the Ca activity coefficient was near zero, however, the Mg activity coefficient was almost 1, and therefore, MgO·Al2O3 spinel generated firstly. When the dissolved oxygen decreased and the Ca activity increased, [Ca] reacted with existed inclusions spinel and generated CaO·MgO·Al2O3 inclusions.

  11. Radiological significance of coal, slag and fly ash samples from the Eastern Black Sea region

    International Nuclear Information System (INIS)

    This work presents a study of natural radioactivity levels in coal and its combustion residues (fly ash and slag) used in the houses in Black Sea Region, Turkey. Coal, fly ash and slag samples were provided from different locations of the region and analyzed by gamma spectroscopy using a high-purity germanium detector (HPGe). Also, chemical analyses of these samples were carried out using energy dispersive X-ray fluorescence spectrometer. The mean 226Ra activity concentrations in coal, slag and fly ash were measured as 83, 99 and 38 Bq kg-1, respectively. The mean 232Th activity concentrations in coal, slag and fly ash were measured as 108, 113 and 50 Bq kg-1, respectively. The mean 40K activity concentrations in coal, slag and fly ash were found to be 366, 381 and 204 Bq kg-1, respectively. The potential radiological hazards associated to these materials were evaluated by calculating the radium equivalent activity (Raeq), the air absorbed gamma dose rate (D), the annual effective dose rate (AED), the external hazard index (Hex) and internal hazard index (Hin) and compared with the internationally accepted or reference values. The mean Raeq values of the coal, fly ash and slag samples were lower than the recommended maximum values 370 Bq kg-1 by the Organization for Economic Cooperation and Development (OECD). The overall mean outdoor terrestrial gamma air absorbed dose rate in coal, fly ash and slag samples are 119, 129 and 62 nGy h-1 and the corresponding outdoor annual effective doses are 0.60, 0.32 and 0.64 mSv y-1, which is higher than the worldwide average (0.07 mSv y-1), respectively. Moreover, the enrichment factors relative to the input coal are calculated for the radionuclide contents observed. Calculated enrichment factor values for 226Ra and 232Th were found 1.14 and 1.01, respectively. (orig.)

  12. The setting time of a clay-slag geopolymer matrix: the influence of blast-furnace-slag addition and the mixing method

    Czech Academy of Sciences Publication Activity Database

    Perná, Ivana; Hanzlíček, Tomáš

    112, Part 1, JAN 20 (2016), s. 1150-1155. ISSN 0959-6526 Institutional support: RVO:67985891 Keywords : blast-furnace slag * geopolymer * setting time * mixing method * solidification * recycling Subject RIV: DM - Solid Waste and Recycling Impact factor: 3.844, year: 2014

  13. Extraction of Metals from Boiler Slag by Sintering

    Institute of Scientific and Technical Information of China (English)

    LI Jinping; GAN Jinhua; HOU Haobo

    2009-01-01

    A new method of recycling aluminum and iron in boiler slag derived from plants that use coal as fuel was presented.The new method can integrate efficient extraction and reuse of the leached pellets together.An elemental analysis of aqueous solutions leached by sulfuric acid was conducted by the EDTA-Na_2-ZnCl_2 titration method,and the components and microstructures of the samples were examined by means of XRF,XRD and SEM.An aluminum extraction efficiency of 86.50%was achieved when the sintered pellets were leached using 4 mol·L ~(-1 )H_2SO_4 with solid/liquid ratio(m/V)of 1:5 at 80 ℃ for 24 h.An iron extraction efficiency of 94.60% was achieved under the same condition for the maximum extraction efficiency of Al.The extraction efficiency of Al and Fe increased with temperature,leaching time and acidity.The concentration of alumina and iron hy-droxide in the final product was determined to be 99.12% and 92.20% respectively.This product of alumina would be used directly for the production of metallic aluminum.

  14. Use of steel slag aggregate in asphalt concrete mixes

    Energy Technology Data Exchange (ETDEWEB)

    Asi, I.M.; Qasrawi, Y.; Shalabi, F.I. [Hashemite Univ., Zarqa (Jordan). Dept. of Civil Engineering

    2007-08-15

    The physical, chemical and mechanical properties of generated steel slag aggregates (SSA) were studied in order to investigate their potential use in asphalt concrete (AC) mixes. Five AC mixes were investigated, notably an AC mix with a 100 per cent limestone aggregate, and mixes comprised of 25, 50, 75, and 100 per cent SSA coarse aggregates. A superpave mix design was used to determine optimum asphalt content (OAC). Steps included the selection of a design aggregate structure, optimization of the asphalt content for the structure, and an evaluation of the moisture sensitivity of the design mixture. The effectiveness of the samples were assessed by their ability to improve indirect tensile strength (ITS); resilient and creep modulus; fatigue life; and stripping and rutting resistance. Various AC mixes containing the SSA were then evaluated. A gyratory compactor was used to compact the test samples, which were then subjected to comprehensive mechanical evaluations. Statistical analyses were then performed to examine the significance of the SSA percentage in the changing ITS values using analysis of variance (ANOVA) calculations. Results of the study indicated that SSA met both superpave consensus properties and Jordanian standards source properties. Chemical and toxic levels were within allowable limits. It was concluded that optimal the replacement percentage of SSA was 25 per cent. 18 refs., 9 tabs., 21 figs.

  15. Kinetics and mechanism of hexavalent chromium removal by basic oxygen furnace slag.

    Science.gov (United States)

    Han, Chong; Jiao, Yanan; Wu, Qianqian; Yang, Wangjin; Yang, He; Xue, Xiangxin

    2016-08-01

    Basic oxygen furnace slag (BOFS) has the potential to remove hexavalent chromium (Cr(VI)) from wastewater by a redox process due to the presence of minerals containing Fe(2+). The effects of the solution pH, initial Cr(VI) concentration, BOFS dosage, BOFS particle size, and temperature on the removal of Cr(VI) was investigated in detail through batch tests. The chemical and mineral compositions of fresh and reacted BOFS were characterized using scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS) system and X-ray diffractometer (XRD). The results show that Cr(VI) in wastewater can be efficiently removed by Fe(2+) released from BOFS under appropriate acidic conditions. The removal of Cr(VI) by BOFS significantly depended on the parameters mentioned above. The reaction of Cr(VI) with BOFS followed the pseudo-second-order kinetic model. Fe(2+) responsible for Cr(VI) removal was primarily derived from the dissolution of FeO and Fe3O4 in BOFS. When H2SO4 was used to adjust the solution acidity, gypsum (CaSO4·2H2O) could be formed and become an armoring precipitate layer on the BOFS surface, hindering the release of Fe(2+) and the removal of Cr(VI). Finally, the main mechanism of Cr(VI) removal by BOFS was described using several consecutive reaction steps. PMID:27521937

  16. Recovery of gold from gold slag by wood shaving fly ash.

    Science.gov (United States)

    Aworn, Amphol; Thiravetyan, Paitip; Nakbanpote, Woranan

    2005-07-15

    Wood shaving fly ash was used as an alternative adsorbent for gold preconcentration from gold slag. The maximum gold adsorption capacity of wood shaving fly ash washed with tap water (WSFW) at 20, 30, 40, and 60 degrees C was 8.68, 7.79, 7.44, and 7.25 mg(Au)/g(adsorbent), respectively, while of activated carbon it was 76.78, 60.95, 56.13, and 51.90 mg(Au)/g(adsorbent), respectively. Deionized water at 100 degrees C could elute gold adsorbed onto WSFW to 71%. The effect of the increasing temperature of water, 30, 60, and 100 degrees C, implied that the adsorption mechanism was mainly physical adsorption. The negative values of enthalpy change (DeltaH) and free energy change (DeltaG) indicated an exothermic and spontaneous process, respectively. The positive values of entropy change (DeltaS) indicated increasing disorder of the system. The advantages of wood shaving fly ash are the purification of gold and the easier recycling of gold from the gold-adsorbed adsorbent. PMID:15925603

  17. An intelligent monitoring system for the detection of slag deposition on a pulverized coal fired burner

    Energy Technology Data Exchange (ETDEWEB)

    Tan, C.K.; Wilcox, S.J.; Ward, J.; Lewitt, M. [University of Glamorgan, Pontypridd (United Kingdom). School for Technology

    2005-08-01

    The objective of this paper is to describe the further development of a monitoring system to detect the presence of so-called burner eyebrows, i.e. relatively large deposits of slag around the burner quarl in pulverized coal fired boilers. Experiments were undertaken with a range of coals and with various artificial eyebrows constructed from cast refractory inserts. The system uses a microphone to detect combustion noise and an infrared sensor which measures flame radiation, and the signals from these cheap, easily installed sensors were analyzed by a hybrid neural network. In tests with two coals, the system was able to distinguish the different eyebrows with a high degree of accuracy if representative data were used to train the network for each particular coal. In further tests with a range of six different coals, the system was able to distinguish between a clean burner and one fitted with a particular sized eyebrow. In this case, it proved to be possible to use only the features from three of the coals in the training process and the data from the remaining fuels for validation. The monitoring system, therefore, appears to be relatively independent of changes to the coal fired by the burner if trained with a representative range of coals. Finally, this paper presents a possible method to detect burner eyebrows via the evaluation of so-called 'eyebrow indices' using a self-organizing map which is trained solely using clean burner sensor patterns.

  18. Mortality patterns of rock and slag mineral wool production workers: an epidemiological and environmental study.

    Science.gov (United States)

    Robinson, C F; Dement, J M; Ness, G O; Waxweiler, R J

    1982-02-01

    An epidemiological and environmental study of rock and slag mineral wool production workers was undertaken at a plant that has been in operation since the early 1900s. Size characteristics of fibres produced by each process at the plant and data from industrial hygiene surveys were used to evaluate current and past exposures. These data suggest that the average historical airborne fibre concentration probably did not exceed 2.5 fibres/cc before 1935 and 1.0 fibre/cc after 1935. A retrospective cohort mortality study was designed to assess mortality patterns. Detailed occupational histories were compiled on all plant employees. All jobs in the plant were assigned to one of eight potential exposure categories to assess the extent and severity of mineral wool exposure and the effect of other significant exposures on employee mortality. Findings included an increase in the number of deaths due to cancer of the digestive system and non-malignant respiratory disease among workers who had over 20 years' exposure to mineral wool or who had survived 20 years since their first exposure to mineral wool. These findings are not inconsistent with those of Enterline's (Symposium on Biological Effects of Mineral Fibres, Lyon, France, September 1979) in the Thermal Insulation Manufacturers' Association's mortality study of men employed in four mineral wool plants. PMID:6279138

  19. The recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor

    International Nuclear Information System (INIS)

    This paper reports the optimization of the process parameters for recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor. The experiments were carried out in an ammoniacal ammonium chloride system. The influence of composition of electrolytes, pH, stirring rate, current density and temperature, on cathodic current efficiency, specific power consumption and anodic dissolution of Zn were investigated. The results indicate that the cathode current efficiency increases and the hydrogen evolution decreased with increasing the cathode current density. The partial current for electrodeposition of Zn has liner relationship with ω1/2 (ω: rotation rate). The highest current efficiency for dissolving zinc was obtained when NH4Cl concentration was 53.46 g L-1 and the anodic dissolution of zinc was determined by mass transfer rate at stirring rate 0-300 r min-1. Increase in temperature benefits to improve CE and dissolution of Zn, and reduce cell voltage. Initial pH of electrolytes plays an important role in the deposition and anodic dissolution of Zn. The results of single factor experiment show that about 50% energy consumption was saved for electrodeposition of Zn in the anion-exchange membrane electrolysis reactor.

  20. Impact of the density of the mould powder on thickness of the layer of liquid slag in the continuous caster mould

    OpenAIRE

    Kania, H; K. Nowacki; T. Lis

    2013-01-01

    The paper presents results of measurements of the thickness of liquid slag layer in concast mould for pulverized, granulated or formed mould powder. The thickest layer of liquid slag was obtained for formed powders.