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Chromium is extracted from its ores by two processes. In the alkaline process, the finely ground ore is roasted with Na 2 CO 3 under oxidizing conditions at 1100 °C. The sodium chromate is leached from the calcine. ... The gangue present in a chromium ore has a significant effect on the temperature of the smelting zone, thereby influencing the ...
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"Chromite ore processing residue" (COPR) is a typical waste from the chromium metal industry. Chromium production started in the first part of the nineteenth century and has been increasing ever since, particularly for use in the production of stainless steel and a wide range of other materials (Blazy and Hermant 2014).The production of chromate, a raw …
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Unfortunately, the formation of a molten state between the chromate ore particles at 1200 °C roasting temperature reduces the mass transfer rate of the oxygen (Yan et al., 2021), resulting in the low chromium extraction efficiency (approximate 85%) of this process for chromium and the larger energy consumption (Matern et al., 2020).
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To establish a cleaner production technology of chromium salt, the pressurized leaching process of chromite ore in 60 wt.% NaOH solution, subsequent separation of a chromium salt from the leached ...
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Selective pre-removal of Mg can effectively enhance the extraction of Cr from COPR. The phase transformation of Cr-containing wastes is critical for Cr extraction. …
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Commercial production of chromium chemicals from ore began in the UK and USA in 1810–25 and involved 'the opening up of the ore with soda and lime and ... efficient extraction of a wide range of ore qual-ities; minimised negative effects of silicates; immobilised vanadium. Lime-based
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It has been shown that EPA Method 3060A does not adequately extract Cr(VI) from chromium ore processing residue (COPR). We modified various parameters of EPA 3060A toward understanding the transformation of COPR minerals in the alkaline extraction and improving extraction of Cr(VI) from NIST SRM 2701, a standard COPR-contaminated soil. Aluminum and …
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The extraction of chromium occurs from chromite ore deposits, typically nestled within extensive layered ultramafic intrusive rocks. Mining operations for chromite ore employ both underground and surface techniques, contingent upon the …
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In addition to conventional extraction methods for solvent extraction of iron and chromium, there are ionic liquid and liquid membrane extraction. Discussion and prospects The extraction, separation and enrichment of chromium and iron are fundamental processes in the preparation of related products following chromite ore acid leaching.
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which combines with chromium easily, was added to the first leaching residue to extract chromium and 95.16 pct chromium was extracted under the optimal conditions. The total vanadium and chromium leaching rates were above 95 pct, achieving the efficient separation and extraction of vanadium and chromium. The established method provides a new ...
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The effective extracting Cr(VI) from chromite ore processing residue (COPR) is the key to achieve COPR detoxification and recovery. We developed an effective method to extract Cr(VI) from COPR via controlling the phase transformation of Cr(VI)-containing minerals. Characteristic analysis showed that Cr(VI) was mainly incorporated in the hydrocalumite (NaCa …
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9. Activity & Ease of Refinement In relation to Chromium's uses: Chromium does not react easily; it possesses passivation, which makes it highly unreactive It does not corrode or oxidise easily Therefore it is used to build & plate things to protect them from corrosion and oxidation Chromium ore (chromite) has a high abundance, and chromium is easy to extract …
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The following are the steps involved in the pyrometallurgical extraction of chromium from chromite ore: Materials and Chemicals Required: Chromite ore (FeCr2O4) Sodium carbonate (Na2CO3) Lime (CaO) Aluminum powder (Al) Heat-resistant crucible Furnace or kiln Heat source (such as an electric arc furnace) Refractory materials for lining the ...
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DOI: 10.1016/j.mineng.2020.106737 Corpus ID: 230586985; Extraction, phase transformation and kinetics of valuable metals from nickel-chromium mixed metal oxidized ore @article{Shen2020ExtractionPT, title={Extraction, phase transformation and kinetics of valuable metals from nickel-chromium mixed metal oxidized ore}, author={Xiao-yi Shen and Hong Mei …
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Chromium ore processing residue (COPR) is a hazardous waste generated during the production of chromate. Currently, approximately 10% of Cr2O3 cannot be extracted after chromite sodium roasting ...
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The combination of tabling and magnetic separation of a 2.5-pct-Cr2O3 ore from Auburn, Calif., resulted in a concentrate containing about 45 pct Cr2O3 with a chromium-to-iron ratio of 1.6:1, a product well suited to chemical …
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Chromite (FeCr2O4 FeCr 2 O 4) is the most commercially useful ore, and is extensively used for extraction of chromium. Chromium is produced in two forms: Ferrochrome by the reduction of chromite with coke in an electric arc furnace. …
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Chromium extraction techniques can be classified as chemical leaching [12], [13], bioleaching [14], [15], electrochemical recovery [16], and calcination [17], [18], [19]. ... 1 V cm −1, applied for 20 days, could yield an 84% extraction rate of chromium from residues produced by processing chromium ore. However, this method requires a lot of ...
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To this end, the test and selection of the specific chemical reagent for efficient chromium extraction from phosphate ore were studied. The effects of some parameters were taken into consideration and optimized. The results show that the chromium content was reduced to approximately 30% in natural phosphate using citric acid as extracting solution.
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Chromium is one of such very important metal, although it is very rarely used in its metal form, is an essential ingredient for stainless steel making. tool, and alloy steel, nickel–chromium heating elements, and plating metals. ... means 60%–70% ore must be left in the stope as working platform. However, this tied-up ore may be extracted ...
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A novel reductive alkali roasting of chromite ores for Carcinogen-free Cr6+-ion Extraction of chromium oxide (Cr2O3) – a clean route to chromium product manufacturing! August 2020 Journal of ...
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Chromium is extracted from its most important ore, chromite, through a process that involves crushing the ore, separating it using gravity and magnetic techniques, and then oxidizing the concentrated chromium through …
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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 process chemistry for the formation of …
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Aluminum-chromium slag (ACS), a by-product produced during the reduction of chromium from chromium ore by metal aluminum smelting, is a typical chromium-containing solid waste, with an output of about 50–60 million tons per year in China (Luo et al., 2020, Zhao et al., 2018a, Zhao et al., 2018c).ACS is mainly composed of aluminum-chromium solid solution ((Al …
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tion of chromium ore and the problems of resource recovery, environmental pollution, and CO 2 emis-sions. METHODS Definitions and Boundaries In this study, the system boundary is defined as a country, and the object of the analysis is chromium ore (Fig. 4). The chromium cycle can be divided into the four stages, namely production stage ...
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Considering the chromium industrial chain and factors such as production, consumption, and recovery tendency of chromium-bearing stainless steel, it is forecasted that China's demand for chromium ore will decline by 2040. This could considerably reduce the security situation of chromium resources.
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Extraction of chromium from COPR, Alkali extraction-COPR (I g. particle diameter 2 mm, 0.8 mm and 0.2 mm) was tre· .:c--1. ith NaOH (1-15M, 25 ml) for 60 min . 1he chromium leached out after the ex~r· ction process was quantified by spectrophotometr c techniques. The particle size or COPR after c romium extraction was determined
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The representative vanadium extraction route from vanadium slag mainly consists of the following procedures: sodium or calcium salts roasting in oxidizing atmosphere, leaching, solution purification and vanadium precipitation [2, 3].It is well known that oxidation roasting is a the key stage in the whole process of vanadium extraction, predominantly deciding the amount …
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Extraction Chromite, FeCr 2 O 4, is the most commercially useful ore, and is extensively used for extraction of chromium. Chromium is produced in two forms: (Chemistry of the Elements, Greeenwood and Earnshaw, Chapter 23). (a) Ferrochrome by the reduction of chromite with coke in an electric arc furnace.
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Evaluation of Hexavalent Chromium Extraction Method EPA Method 3060A for Soils Using XANES Spectroscopy. Environmental Science & Technology 2011, 45 (24) ... Treatment of Hexavalent Chromium in Chromite …
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DOI: 10.1016/j.jhazmat.2022.129754 Corpus ID: 251507844; Sufficient extraction of Cr from chromium ore processing residue (COPR) by selective Mg removal. @article{Zhang2022SufficientEO, title={Sufficient extraction of Cr from chromium ore processing residue (COPR) by selective Mg removal.}, author={Jing Zhang and Wenyu Xie and Shasha …
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Here's an overview of the typical process for mining and processing chromium ore: Extraction: The first step in chromium ore mining is the extraction of the ore from the earth's crust. Chromium ore is typically found in …
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A new leaching process for preparing chromium oxide from chromite was studied in this paper, using Cr(VI) extracted from the remediation treatment of chromite ore processing residue (COPR) as an oxidant. Thus, the "detoxification" of deposited COPR could be achieved and no new Cr(VI)-bearing substances would be generated in preparation process of …
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Nickel is extracted via pyrometallurgical or hydrometallurgical processes depending on the ore. 2). Important nickel alloys include nickel-copper alloys, nickel-chromium alloys, and nickel-base superalloys used in applications requiring high heat resistance. 3).
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5a. The Extraction of Lead. Because its position in the reactivity series of metals, lead can be extracted using carbon (coke) in a smelting furnace.Because lead is below carbon, that is less reactive than carbon, lead can be displaced by carbon from lead oxides or lead sulfides in a sort of displacement reaction. The principal ore of lead is galena, chemical formula PbS lead …
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X-ray fluorescence (XRF) was used to evaluate the levels of chromium, iron, and calcium in the ore. Volumetric analysis was performed to assess chromium and iron, whilst gravimetric …
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