Chromite ore processing residue (COPR) is a by-product generated after the leaching of sodium chromate by roasting chromite ore at 1200 °C. However, the …
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Typically, standard metallurgical grade chromite, used in alloy steel making, is 48% Cr203 and 3:1 Cr:Fe ratio. Chemical grade chromite ore, used to manufacture sodium dichromate, generally has a Cr203 content of over 44%, with a Cr:Fe ratio of about 1.5, and a silica content of less than 3.5%.
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The processing cycle of Fe-Cr involves the chemical reduction of the chromite ore. Smelting of HC Fe-Cr ferro-alloy. HC Fe-Cr and charge chrome are normally produced by the conventional smelting process utilizing carbo-thermic reduction of chromite ore (consisting oxides of Cr and Fe) using an electric submerged arc furnace …
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Detailed characterization and quality improvement study on low-grade chromite ore from Ghutrigaon, Odisha, India, was investigated to improve the Cr/Fe …
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STAR process treats such dust and Fe–Cr–Ni metal is recovered and recycled at stainless steel production. ... The chromium metal commercially separated by oxidizing chromite ore to Cr 2 O 3, then the metal is attained by heating …
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The IRMS process has previously been utilised in India to upgrade the Cr: Fe ratio of chromite ore, to upgrade mineral sand ore (e.g. ilmenite and rutile) and to upgrade ferromanganese ore, as ...
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Chromite ore processing residue (COPR) is a waste byproduct of chromate production that contains high levels of hexavalent chromium (Cr[VI]). Although the high temperature chromite process was ...
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1. Introduction. Chromite ore processing residue (COPR) is an industrial waste generated during the extraction of Cr(VI) from chromite ore using the high-temperature lime-based roasting process [[1], [2], [3]].When COPR undergoes weathering reactions during the deposition process, it would release highly toxic and mobile Cr(VI) …
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Introduction. Chromite ore processing residue (COPR) is a byproduct produced in chromite processing at high temperature ... The Cr and Fe were reduced directly into (Cr, Fe) 7 C 3 alloy by the solid carbon from Fe-C-bearing dust, and then recovered by magnetic separation (Wu et al., 2019, Zhu et al., 2018). The Pb and Zn …
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Figure 8 presents a flow sheet of the process for treating low-Fe (II) chromite proposed in this work. A product Cr 2 O 3 was prepared from LFC by using the proposed process, with a chemical …
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It is a great challenge to find an effective method for the treatment of chromite ore processing residue (COPR), due to the highly toxic and mobile characteristic of Cr(VI) in the sludge. ... This study first reported the efficient reduction of Cr(VI) and recovery of Fe from COPR by waste molasses-assisted hydrothermal treatment. Under optimal ...
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1. Introduction. The natural mineral chromite is widely utilized by high-lime roasting technique to obtain chromate products due to the needs of leather, catalysis, metallurgy and other industries, in which a large amount of chromite ore processing residue (COPR) is produced (Dermatas et al., 2006; He and Traina, 2005).A small …
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Fluxing of South African chromite ore with colemanite South African chromite ores and concentrates are blended to obtain a Cr/Fe ratio that is high enough to produce 'charge chrome', a special grade of high-carbon ferrochrome (HCFeCr). Charge chrome contains approximately 50–53% Cr, 6–8% C, 4–6% Si, and the balance Fe, with minor ...
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A clean hydrometallurgical process without hexavalent chromium is demonstrated in this study. First, the chromite is decomposed in sulfuric acid solution with oxidation, and Cr 3+ is extracted into the acid solution. Seed crystal is added to acid solution, and the jarosite is precipitated by the hydrothermal treatment.
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Chromite ore processing residue (COPR) is an industrial waste generated during the extraction of Cr(VI) from chromite ore using the high-temperature lime-based roasting process [[1], [2], [3]]. When COPR undergoes weathering reactions during the deposition process, it would release highly toxic and mobile Cr(VI) due to the …
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The present investigation emphasized on the liberation and beneficiation characteristics of Indian chromite oreto improve the Cr: Fe ratio . The off grade chro mite samp le ofSukinda region,...
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ABSTRACT. The control of chromite feeds is supported by alternating modes of operation that respond to imbalances in feed stockpiles. Conventional classifications of chromite relate to its end uses: metallurgical (with high Cr 2 O 3 content and Cr:Fe ratio close to 3, to produce ferrochrome), chemical and refractory. However, natural chromite is …
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It is therefore evident that Fe- and Cr-oxide changes during processing may be considered separately on a thermodynamic level. Davies et al. (2022) performed a fundamental investigation to show the behavior of chromite when exposed to hydrogen at elevated temperatures. ... Canaguier showed that Mg-containing chromite ((Fe, Mg)Cr 2 …
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The off grade chro mite samp le ofSukinda region, India analysed 40.8% of Cr 2 O 3 with Cr:Fe rat io of 1.7 and 5.8% of SiO 2 which was not suitable for metallu rgical industry. Detailed ...
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In the paper are shown the history, processing and applications of chromite. Chromite is an oxide of iron and chromium with the chemical composition FeO.Cr2O3 and belonging to the spinel group ...
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Residues from mining and chromite processing are often toxic, not only because of the presence of hexavalent Cr (Cr(VI)) but because of the reagents and other waste materials in overburden and wastes. ... that can be represented as FeCr 2 O 4 or (Fe 2+,Mg)[Cr,Al,Fe 3+] 2 O 4 (Murthy et al., 2011, Sanchez-Segado et al., 2015). Fig. 11.1 …
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Characterization and beneficiation of Anka chromite ore using magnetic separation process. Journal chromite ore shows that the Cr2O3 content has increased to 48% of Minerals & Materials Characterization & Engineering 6 (2), 143–150. from 36.84% with a maximum Cr:Fe ratio of 6.2:1. Akdemir, Ü., Hiçyilmaz, C., 1996.
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Several carbides can form preferentially to the metallic Cr and Fe during the reduction process of chromite ores. Cr/Fe ratio plays a role in the determination of the C content of the Fe-Cr. As Cr has higher affinity to form carbides than Fe, a higher Cr/Fe ratio means a higher C content in the Fe-Cr. Properties of Fe-Cr
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Chromite deposits are mined by both underground and surface techniques. Much of the ore is rich enough to be used directly: for production of ferrochromium, a rich, lumpy ore …
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Sulfuric acid-based leaching is a promising cleaner method to produce chromium salts, but its feasibility for treating low Fe(II)-chromite still remains to be proven. A Box–Behnken design (BBD)-based set of experiments for sulfuric acid leaching of low Fe(II)-chromite was utilized in this work for generating an experimental dataset for revealing the functional …
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Our study provides a new insight into Cr (VI) reoccurrence in rCOPR and helps in predicting its environmental risk in nature. Keywords: Cr (III)−Fe (III) hydroxides; …
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Natural chromite is a mixture of chromium and iron oxides, with varying amounts of magnesium and aluminium, the general formula being …
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the BIC chromite resources, historical preference has been for the higher grade and more physically competent seams that produce a lumpy product as represented by the LG6 seams (Cr/Fe ratio of 1.5–2 once beneficiated), followed by the MG1 or 2 seams (Cr/Fe ratio of 1.5–1.8 once beneficiated).
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Figure 8 presents a flow sheet of the process for treating low-Fe (II) chromite proposed in this work. A product Cr 2 O 3 was prepared from LFC by using the proposed process, with a chemical composition as follows: Cr 2 O 3 % = 99.36%, MgO% = …
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ABSTRACT In the paper are shown the history, processing and applications of chromite. Chromite is an oxide of iron and chromium with the chemical composition FeO.Cr2O3 …
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Abstract. Chromium (Cr) is a versatile element used in numerous applications in the metallurgical, chemical, foundry sand, and refractory industries. Chromite (FeCr2O4) is the only commercially ...
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The issue that the residual Cr(VI) in the reduced chromite ore processing residue (rCOPR) is slowly released during deposition has attracted increasing attention. …
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Another classification method is based on Cr/Fe ratio, and the ores are divided into three groups: metallurgical grade (Cr/Fe > 2.5), chemical grade (Cr/Fe ≈ 1), and refractory grade, which contain a large amount of Al 2 O 3 ((Al 2 O 3 + Cr 2 O 3) > 60%) . Therefore, chromite processing method depends on the type of the ore in terms of ...
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About 40% of the Indian chromite ore reserves are suitable for metallurgical purpose due to higher Cr:Fe ratio. The present investigation emphasized on the liberation and beneficiation characteristics of Indian chromite oreto improve the Cr: Fe ratio. The off grade chromite sample ofSukinda region, India analysed 40.8% of Cr 2 O 3 > with Cr:Fe …
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Idiomorphic chromite is the only ore mineral appearing in economic quantities. The average content of the ore is 26% Cr 2 O 3 and the Cr/Fe ratio is 1.55. The Kemi chromium mine is an open-pit mine with a waste rock to ore ratio of 5.5:1. At Kemi, the ore from the mine contains 11% iron and 25.5% Cr 2 O 3.
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The chromium (Cr) content of stainless steel originates from recycled scrap and/or ferrochrome (FeCr), which is mainly produced by the carbothermic reduction of chromite ore. Ever-increasing pressure on FeCr producers to curtail carbon emissions justifies migration from traditional FeCr production routes. The interaction between …
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