· The main advantage of the process is that, under reducing atmosphere and subsequent leaching conditions, the oxidation of Cr3+ to Cr6+ is completely avoided; thereby decreasing the risk of land
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· In the sulfuric acid leaching process for chromite, a strong oxidizing environment is maintained by the presence of oxidant and the employment of concentrated sulfuric acid. From Fig. 1 it can be confirmed that Cr 2 (SO 4 ) 3 could precipitate from the solutions and be stable under leaching conditions (area delimited by the dotted box),
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:Chromite Ore Processing ResidueCOPR · An advanced sulfuric acid leaching process of chromite was finally proposed. Experimental results showed that the chromium sulfates were completely
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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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· For example, most of the chromite mines in the Philippines and Vietnam are chromite sand. After desliming by washing, the grade of chromite sand will rise greatly, and it will be further improved by jigs and shaking tables. 2. Concentration. The predominant method to concentrate chromite stone is gravity separation.
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· Because of the acute toxicity of Cr(VI)-bearing substances, the pollution problem caused by chromite process residue has become a worldwide concern. In the view of relevant studies, the technologies based on the alkali treatment cannot fundamentally resolve the pollution problem, because the oxidation of Cr(III) to Cr(VI) is
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C.H. Weng et al., “Chromium leaching behavior in soil derived from the chromite ore processing waste”, The science of the total environment 154 (1994), 71–86. Article Google Scholar R.Mattuck and N.P. Nikolaidis.“Chromium mobility in freshwater
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· In the leaching process of chromite, how to quickly separate sodium chromate from leaching slurry is a key issue. In this paper, a simple method, named thermal sedimentation, was firstly
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· Abstract. Supply of world chromite (chrome ore) has come under severe pressure over the past year driven by strong demand for ferrochrome used in ferroalloy production for making stainless steel. Many of the strategic minerals are inputs into products in fast-changing markets. This article reviews the major process flow sheets in practice
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· Chromite ore processing residue (COPR) is a byproduct generated in producing chromium and chromium salts by high-temperature (approximately 1200 C) roasting. COPR does great harm
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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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· A new metallurgical process for extracting chromium from chromite ore is proposed to overcome the severe chromium (VI) pollution in chromate production industry. When the 60 wt.% KOH solution was used to decompose chromite ore, the chromium and iron ions in chromite ore were oxidized into soluble K 2 CrO 4 crystal and insoluble KFe
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:Sulfuric AcidPublish Year:2017The physical chemistry of leaching of water soluble Chromate is examined for determining the barrier to the extraction of Cr 6+ ions. In this respect the role of spinel is examined.
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· Note that flotation of conventional chromite rich ores is usually done in a mill-float–mill-float (MF2) During the leach process, in addition to NO (g) and NO 2(g), the system may contain a number of other nitrogen compounds (HNO 2, N 2 O 4, NO 2-,
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· In the liquid phase oxidation leaching process of chromite salt, a new dynamic-static combined stirred mode is proposed. That is, a static cylindrical baffle is fixedly installed at a certain
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· Abstract. The sulfuric acid leaching process is widely considered to be a cleaner technology to prepare chromium salt from natural chromite as no Cr (VI)-bearing wastes are generated or discharged
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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 Cr3+ 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 ResidueRecovery of Chromium · To establish a cleaner production technology of chromium salt, the pressurized leaching process of chromite ore in 60 wt.% NaOH solution, subsequent
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:Chromite OreChromium Salt · Abstract The effects of the nitric acid concentration, leaching time, leaching temperature, and solid-to-liquid ratio on leaching efficiency were examined. From those
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· A new leaching process for preparing chromium oxide from chromite was studied for this paper, using Cr (VI) extracted from the remediation treatment of chromite ore processing residue (COPR) as an
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by chromite process residue has become a worldwide concern. In the view of relevant studies O2, air, O3 or their mixtures, and then prepared sodium chromate by pressure leaching. In this process,
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:Chromite OreMinerals · This paper aims to study the sulfuric acid leaching process using chromite as a raw material via either microwave irradiation or in the presence of an oxidizing
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:Chromite OreRecovery of ChromiumChromite MineralPublish Year:2019The results of the leaching kinetics analysis indicated that the leaching of Fe and Cr from the COPR was controlled by a surface chemical reaction, and the leaching of Al was
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· Safe management and disposal of chromite ore processing residue (COPR) is an unsolved global problem. In spite of several global research efforts, the problem of safe management of COPR and redemption of dump sites has remained unsolved. There is a high risk for all living beings in and around the COPR dump sites
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· A process flow diagram indicating the likely process steps to be utilized for pelletized pre-reduction before acid leaching to improve the Cr/Fe ratio of chromite. In this general process flow diagram ( Fig. 1 ), Process steps 1–5 are based on the currently applied pelletized chromite pre-reduction process.
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:Sergio Sanchez-Segado, Animesh JhaPublish Year:2013In this study, a clean hydrometallurgical process without the generation of hexavalent chromium is demonstrated. First, the chromite was decomposed and leached by sulfuric
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· Roasted ilmenite samples were treated in a two-stage leaching process, where the first step involved water leaching and this was followed by organic acid (mixture of 0.25 M oxalic and 0.01 M ascorbic acid) leaching for 2
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· In the liquid phase oxidative leaching system of chromite, the reagents, including NaOH, HCl, H 2 SO 4, H 3 PO 4, HNO 3, NH 3 ·H 2 O, Chrome azurol S, Emulsifier OP, Ethylenediamine, Propanone, Bromohexadecyl pyridine, Cetyl pyridinium bromide (CPB), Diphenyl carbamide, Phenolphthalein, Potassium biphthalate etc.,
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· Flow sheet of the proposed process route for treating low-Fe (II) chromite. 4. Conclusions. To investigate the feasibility of sulfuric acid-based leaching of low Fe (II)-chromite, the optimal experimental conditions for leaching of a Zimbabwean chromite with 1.52% of FeO were determined by a Box–Behnken design (BBD).
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Amongst different organic acids, oxalic acid has been reported to be more effective in leaching of lateritic COB (Sukla, et. al., 1993). Leaching kinetics study is an inevitable factor to justify the reaction mechanisms
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