Towards holistic technology solution to chromite ore
Schematic diagram of Chromite ore processing is shown in the Process flow diagram with chemical reactions involved (Fig. 1). Chromite ore (FeO·Cr 2 O 3 ) in rock form contains about Cr 2 O 3 50–61%; FeO 11–19%, which is generally available with other minerals MgO 9–16%, Al 2 O 3 10–16%, Fe 2 O 3 1–16%.
Process flow chart for the production of a chromium salt from chromite ore.
The optimum process conditions of leaching treatment were found to be a temperature of 176 °C, a dichromic acid/chromite mass ratio of 0.12, and a sulfuric acid concentration of 81%.
Immobilization of chromite ore processing residue with alkali-activated
1. Introduction. Chromite ore processing residue (COPR) is an industrial solid waste [1].It has been reported that 2–3 t of COPR is generated in the production of 1 t chromic salts [2].Accumulation of COPR takes up considerable land, and when the leached hexavalent chromium flows into the water after rainfall, it pollutes the water and the soil …
Recovery of chromium by calcium-roasting, sodium-roasting …
Zhao et al. conducted the acidic leaching process of chromium from chromite leaching residue. It was found that increasing reaction temperature and acidity of the solution had a positive effect on the leaching efficiency, while reaction time had a …
Recovery of chromium from residue of sulfuric acid leaching of chromite
The optimum process conditions of leaching treatment were found to be a temperature of 176 °C, a dichromic acid/chromite mass ratio of 0.12, and a sulfuric acid concentration of 81%.
Sulfuric Acid Leaching of South African Chromite. Part 1: …
The sulfuric acid leaching process is regarded as a promising, cleaner method to prepare trivalent chromium products from chromite; however, the decomposition mechanism of the ore is poorly ...
Effects of particle size and acid addition on the remediation …
Semantic Scholar extracted view of "Effects of particle size and acid addition on the remediation of chromite ore processing residue using ferrous sulfate." ... Leaching kinetics of acid-soluble Cr(VI) in ... was caused by anion exchange of sulfates for chromate in the layered double hydroxide mineral hydrocalumite, a process for which scanning ...
Chemistry and Leaching Behavior of Chromite Ore
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 ...
Mineral processing: leaching process of chromium and
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(PDF) Potential Processing Routes for Recovery ofWEBA process flow diagram indicating the likely process steps to be utilized when combining pelletized carbothermic pre-reduction, to selectively separate Fe from the …
Leaching kinetics of acid-soluble Cr(VI) from chromite …
Key words: leaching; kinetics; hydrofluoric acid; hexavalent chromium; chromite ore processing residue 1 Introduction Chromite ore processing residue (COPR) is a solid residue produced by the so-called high lime process. COPR was classified as a hazardous waste for containing 1%−2% hexavalent chromium (Cr(VI)) [1], which is a mutagenic ...
Leaching of hexavalent chromium from young chromite ore …
Chromite ore processing residue (COPR) is a waste derived from the chromate extraction from roasted ores and is deposited in some countries in landfills. The objective of this study was to investigate the leaching characteristics of hexavalent Cr [Cr(VI)] from two COPR samples obtained from unlined landfills in the Kanpur area of …
Immobilization of chromium ore processing residue by alkali …
Chromium ore processing residue (COPR) is classified as hazardous solid waste because of the leachable Cr(VI). Cementitious materials are often used to solidify and stabilize heavy metals. However, most of them focus on the leaching concentration of particles after solidification and stabilization and lack research on leaching …
Leaching of Valuable Elements from the Waste Chromite Ore …
The L/S is a very crucial factor in the acid-leaching process of an ore or residue. 33 To figure out the influence of L/S, a series of experiments with varying L/S from 4 to 10 mL/g at 60% of w/w % H 2 SO 4, 373 K, and a leaching time of 6 h were conducted, and the results are shown in Figure Figure3 3.
A cleaner method for preparation of chromium oxide from chromite ore
Abstract. 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 solution and Cr 2 O 3 preparation from the intermediate product BaCrO 4 were systematically investigated, and a new highly …
Pressure oxidative leaching of Indian chromite ore in …
A novel process for leaching chromite ore has been proposed. Compared to the traditional alkaline roasting process, the new hydrometallurgical process lowers effectively the reaction temperature and enhances the leaching efficiency through pressure oxidative leaching with pure oxygen (O 2) in concentrated sodium hydroxide (NaOH) …
Leaching of Valuable Elements from the Waste …
chromite ore processing residue (COPR) is an inevitable solid emission in chromite salt production. It is an industrial waste produced during the extraction of Cr(VI) from a chromite ore using the high-temperature roasting process.11 In general, the COPR is alkaline (pH > 12),5,7 and because of the presence of partially water-soluble ...
PGM extraction from oxidized ores using flotation and leaching …
Direct leaching of oxidic PGM ore using different acids yielded relatively low PGM extractions. Leaching in hydrochloric acid achieved extractions of 36.6% Pt and 8.8% Pd, nitric acid achieved extractions of 34.5% Pt and 7.1% Pd. The best leaching results were obtained using aqua regia, with extractions of 48% Pt and 24.5% Pd. In view of the ...
(PDF) A Review of Chromite Ore Processing …
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 …
Chemistry and Leaching Behavior of Chromite Ore …
DOI: 10.1089/ees.2018.0047 Corpus ID: 239831715; Chemistry and Leaching Behavior of Chromite Ore Processing Residue from the Soda Ash Process @article{Du2018ChemistryAL, title={Chemistry and Leaching Behavior of Chromite Ore Processing Residue from the Soda Ash Process}, author={Yaguang Du and Maria …
Long-Term Leaching Behavior of Chromite Ore Processing …
Leaching characteristics of chromium ore processing residue (COPR) for the long term (simulating a 20-year leaching scenario) were investigated using laboratory flow-through column testing with ...
Leaching of a low grade Egyptian chromite ore
The Fe content in the FeCr produced depends on the chromite spinel Cr/Fe ratio. Therefore, the selective removal of Fe from the chromite spinel using different combinations of chromite pre-oxidation, pre-reduction, and sulphuric acid leaching was investigated. The Cr/Fe ratio of the case study ores could be increased from 1.57 up to …
Leaching of Valuable Elements from the Waste Chromite …
The optimum parameters for COPR leaching were as follows: mechanical ball-milling time of 120 min, sulfuric acid concentration (w/w % H2SO4) of 60%, reaction temperature (T) …
Advances towards a Clean Hydrometallurgical …
With the goal of improving the leaching behavior of chromite in sulfuric acid solution, Geveci et al. used perchloric acid as the catalyst in the leaching process at atmospheric pressure, achieving 83% chromium …
A clean and efficient leaching process for chromite ore
Abstract The effects of the nitric acid concentration, leaching time, leaching temperature, and solid-to-liquid ratio on leaching efficiency were examined. From those …
Sulfuric Acid Leaching of South African Chromite. Part 2: Optimization
The sulfuric acid leaching process is regarded as a promising, cleaner method to prepare trivalent chromium products from chromite; however, the decomposition mechanism of the ore is poorly ...
Leaching kinetics of acid-soluble Cr(VI) from chromite ore …
The leaching process of acid-soluble Cr(VI) from COPR is controlled by the diffusion through the product layer. The apparent activation energy is 8.696 kJ/mol and the reaction orders with respect to HF concentration and particle size is 0.493 8 and −2.013 3, respectively. ... Leaching kinetics of acid-soluble Cr(VI) in chromite ore processing ...
A clean and efficient leaching process for chromite ore
Abstract. In order to improve the chromate salts cleaner production technology, a pressure leaching process for chromite ore in 50 wt% KOH solution was studied for the first time and the results were presented in this manuscript. It was found out that the chromium extraction rate increased significantly with the increase of temperature …
Sulfuric acid leaching kinetics of South African chromite
The sulfuric acid leaching process is regarded as a promising, cleaner method to prepare trivalent chromium products from chromite; however, the decomposition mechanism of the ore is poorly ...
Recovery of chromium from residue of sulfuric acid leaching of chromite
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. However, some insoluble anhydrous chromium sulfate could precipitate causing a serious chromium resource loss and potential pollution problems.
Leaching of Valuable Elements from the Waste Chromite Ore …
The optimum parameters for COPR leaching were as follows: mechanical ball-milling time of 120 min, sulfuric acid concentration (w/w % H 2 SO 4) of 60%, …