Ferrochrome (FeCr) is the main source of chromium (Cr) units used in modern-day chromium (Cr) containing alloys. The vast majority of produced Cr is used during the production of stainless steel, which owes its corrosion resistance mainly to the presence of Cr. In turn, stainless steel is mainly produced from Cr-containing scrap …
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Therefore, the ash obtained in this research is less dangerous to the environment and humans than in the case of products from incineration processes described by Velusamy et al., who reported the presence of Cr(VI) in the ash, or Kavouras et al., who reported the oxidation ratio from 74% to of Cr(VI)/Cr total, depending …
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Du Y, Chrysochoou M. Microstructural analyses of Cr(VI) speciation in chromite ore processing residue from the soda ash process. Journal of Hazardous Materials. 2020; …
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A novel reduction reaction for extracting Cr 2 O 3 from chromite ores is demonstrated by excluding the formation of carcinogenic chromate (Cr 6+) intermediates.We have investigated in detail the underpinning high-temperature reduction reaction: FeCr 2 O 4 +Na 2 CO 3 +2[C]=[Fe]+Na 2 Cr 2 O 4 +3CO (g), which defines the …
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According to Elahi et al., 2020, Cr (VI) can be severely harmful to plants at concentrations as low as 5 mg/kg in soils and 0.5 mg/L in solution. Cr (VI) is linked to a …
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Approximately 95% of the world's chromite ores are employed in the metallurgical in- dustry as ferrochrome alloy (50-70% chromium in iron) ( Kogel et al., 2006;Papp, 2011).
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Milling is the only process step applied during chromite beneficiation that has been implicated in the possible generation of Cr(VI). However, only dry milling of chromite has been proven to generate Cr(VI) (Beukes and Guest, 2001, Glastonbury et al., 2010). Extreme grinding (i.e. pulverization), which is not a typical comminution technique ...
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Chromite concentrate, when combined with a reductant such as coal or coke and a high temperature furnace can produce ferrochrome. Ferrochrome is a type of ferroalloy that is an alloy in between chromium and iron. ... Cr-III is converted to Cr-VI. As with chromite ore, ...
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III may be converted to mobile Cr-VI. Dry milling (grinding) of chromite ore is now known to convert Cr-III to Cr-VI and efforts are required to avoid producing and spreading hexavalent chromium during mining activity. Studies suggest that milling ores while wet or in a non-oxygenated atmosphere (i.e. nitrogen) will decrease Cr-VI formation.
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Chromite is a crystalline mineral composed primarily of iron(II) oxide and chromium(III) oxide compounds. It can be represented by the chemical formula of FeCr2O4. It is an oxide mineral belonging to the spinel group. The element magnesium can substitute for iron in variable amounts as it forms a solid solution with magnesiochromite (MgCr2O4). A …
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The chromite concentrate was fused with KOH above 773 K under a flow of ambient air in order to oxidize Cr(III) to Cr(VI). ... The effective extracting Cr(VI) from chromite ore processing residue ...
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DOI: 10.1016/j.jhazmat.2020.122385 Corpus ID: 211726800; Microstructural analyses of Cr(VI) speciation in chromite ore processing residue from the soda ash process. @article{Du2020MicrostructuralAO, title={Microstructural analyses of Cr(VI) speciation in chromite ore processing residue from the soda ash process.}, …
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Plant exposure to excess Cr-III or VI can negatively affect plant health and survival. It is still unclear whether Cr-III or Cr-VI is more toxic to plants. Chromium toxicity to plants has …
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Abstract. Chemical reduction combined with microbial stabilization is a green and efficient method for the remediation of hexavalent chromium (Cr (VI)) contaminated …
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Based on the aforementioned studies, Cr(VI)-resistant alkaliphiles exhibit tremendous potential to remove elevated concentrations of Cr(VI) from alkaline …
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This review examines the evidence of Cr (VI) as a neurotoxicant that targets mitotic cells of the brain and may contribute to various neurological disorders. It also …
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Chromium (Cr) is a critical metal that supports the development of China's emerging industries. Approximately 82% of China's Cr is used to manufacture stainless steel. However, the stainless-steel product chain has often been referred to as a "black box" in Cr substance flow analysis, leading to limited guidance for Cr management.
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In this work, we investigated chromium extraction using a pyrometallurgical process and the subsequent production of nano-sized chromium oxide from Turkish chromite concentrate by assessing the effects of the base amount, fusion temperature, and fusion time on the chromium conversion.
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Chromite ore processing tailings and low-grade manganese ores are typically considered waste due to their limited or negligible utility, leading to environmental and storage concerns. Researchers globally have explored various methods to utilize or upgrade these wastes, particularly because dumping chromite ore has been linked to …
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The chromite concentrate typically contains Cr(VI) in the range 2-5 mg Cr(VI) kg −1 depending upon the nature of ore deposit as reported by Kapure and Mohan Rao (2008). During the production of ...
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In this study, the possibility of chromium extraction from Turkish chromite concentrate and the production of chromium oxide were investigated. For the conversion of chromium(III) into chromium(VI), NaOH was employed, as well as air with a rate of 20
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DOI: 10.1016/J.MINPRO.2013.05.011 Corpus ID: 96945255; Process optimization for bio-beneficiation of a chromite concentrate by a Cr(VI) reducing native microbe (Bacillus sp.) @article{Dhal2013ProcessOF, title={Process optimization for bio-beneficiation of a chromite concentrate by a Cr(VI) reducing native microbe (Bacillus sp.)}, …
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However, only dry milling of chromite has been proven to generate Cr(VI) (Beukes and Guest, 2001; Glastonbury et al., ... during chromite concentrate beneficiation the milling step would be aimed only at liberating the chromite crystals from the gangue minerals. This is in contrast to the dry milling tests conducted by Beukes and Guest ...
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chromite content of 20.03% with silica as the major gangue measured at 33.50%. The iron oxide content assayed at 17.94%. The chromite content corroborates the research that was conducted by [4] which indicated that there is sufficient amount of chromite in tailings streams measuring between 9–20% Cr 2 O 3.
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Almost complete reduction of Cr(VI) in the chromite concentrate was achieved in ~ 12 min of incubation under the optimized conditions of pH ~ 7.0, 35 °C temperature and 60% pulp density with the ...
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InlEnllnllonmnnmnmoF zyxwvutsrqpo mmaua PRot ci5me ELSEVIER Int. J. Miner. Process. 50 (1997) 87-96 Investigation of chrome( VI) oxide production from chromite concentrate by alkali fusion Ciineyt Arslan *, …
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Almost complete reduction of Cr (VI) in the chromite concentrate was achieved in ~ 12 min of incubation under the optimized conditions of pH ~ 7.0, 35 °C …
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Almost complete reduction of Cr(VI) in the chromite concentrate was achieved in ~ 12 min of incubation under the optimized conditions of pH ~ 7.0, 35 °C temperature and 60% pulp density with the ...
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Research highlights High tailing losses from the existing chromite plants (9–20% Cr 2 O 3). Accumulation of huge amount of low and sub-grade fines (10–30% Cr 2 O 3). Utilization of stockpiled tailings containing chromite values. Concentrate with required Cr 2 O 3 content and Cr/Fe ratio. Unrecoverable ultrafine chrome particles.
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Conversion was calculated based on the amount of Cr(VI) formed via oxidation of the Cr(III) from the chromite concentrate: (1) Conversion % = M Cr 6 + g / W g × 0.3345 × 100, Where, M Cr6 + is the quantity of hexavalent chromium dissolved in the solution in grams, W is the sample weight in grams, and 0.3345 is the measured fraction …
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