WO1997046724A1 - Process for obtaining chromium enriched chromite from ...
A process for obtaining chromium enriched chromite from chromite ores comprising the steps of: dry chlorinating the ores at a temperature between 400 °C and 750 °C to produce a chlorinated substrate containing acid soluble ferric oxide, acid soluble ferric chloride and acid insoluble chromium enriched chromite; digesting the chlorinated substrate with hydrochloric …
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Selective Extraction of Chromium from EAF Stainless Steel Slag …
Chen et al. studied the chromium extraction rate from Philippine chromite ore at a high oxygen pressure in a KOH submolten salt ... the leaching rate reached 98%. Thus far, investigations on the selective extraction of chromium from EAF slag by pressurized oxidation in NaOH solution have rarely been reported. The experimental parameters (e.g ...
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Study on extraction of iron from chromite - Åbo Akademi …
N2 - Research about extraction of iron from chemical-grade South African chromite by carbothermic reduction and hydrochloric acid leaching was conducted in this study. It was found that temperature had a remarkable effect on the extraction yield of iron and that the optimum experimental temperature was 1100 °C, which coincides with the ...
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Flotation of chromite and serpentine | Semantic Scholar
Effect of particle shape properties on selective separation of chromite from serpentine by flotation. ... The article presents the possibility of additional extraction of chromite concentrate from enrichment tails of chromite containing ores by the gravitational method. The enrichment of … Expand.
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Preparation of Potassium Dichromate Crystals from the Chromite …
In the present investigation, the oxidizing roasting process of chromite with sodium carbonate to prepare potassium dichromate crystals was studied in the microwave field with air, by heating the chromite and sodium carbonate. The chromite and sodium carbonate heated separately at 1000 °C in the microwave oven (frequency: 2.45 GHz; power 1.5 kW) in …
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Preparation of Superconcentrate and Chromium Powder from Chromite …
Non-traditional metallurgical technology of comprehensive processing of Sevan chromite (with a 43–46% Cr 2 O 3 content) is developed allowing chromium extraction from local chromite in the form of more expensive chromium powder. The process of increasing the reactivity of chromite concentrate (with a Cr 2 O 3 content of 53%) as a result of thermal and …
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Characterization of copper chromite catalysts for methanol ...
Copper chromite catalysts have been characterised by total and metal surface areas. X-ray powder diffraction, thermal gravimetric analysis and selective extraction of copper oxide in order to investigate the nature of the active catalyst for methanol dehydrogenation. After reduction in hydrogen at atmospheric pressure, the catalyst surface has ...
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Acid leaching of chromite - ScienceDirect
Selective chromium (Cr) leaching from stainless steel slag (SS slag) by alkali roasting followed by water leaching was investigated. ... extraction tailings containing high chromium concentrations by synergistic carbothermal reduction of the mixture of chromite and the vanadium extraction tailings. Experiments show that the recoveries of ...
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Selective Extraction of Chromium from EAF Stainless Steel Slag …
Under conditions of temperature 350°C, KOH-to-chromite ore ratio 2:1, stirring speed 700 rpm, KNO3-to-chromite ore ratio 0.8:1, oxygen partial pressure 50%, and gas flow 1 L/min, chromium ...
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Kell hydrometallurgical process for extraction
has been shown to provide high (>95 per cent) and selective extraction efficiencies for the key valuable metals, i.e. Pt, Pd, Rh, Au, Ni, Co, and Cu. The Kell Process consists of several commercially proven unit ... keep the chromite level in the concentrate below the smelter plant's limits; other operations have to limit the amount of
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Robinson M, Wilson H.B., Crosby A.D, Talati K (1981)"Beneficiation …
Article citations More>>. Robinson M, Wilson H.B., Crosby A.D, Talati K (1981)"Beneficiation of Chromite Ore and other ores by Selective Chlorination" Journal of Extraction Metallurgy, London Sept, 1981, pp 393 – 403.
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WO2020188527A1 - Recovery of pgms and chromite from mixed …
This invention relates to a process for the enhanced recovery of chromite and platinum group metals (PGMs) from a mixed chromite/PGM ore. Ore is ground 12, classified 14, to produce a coarse fraction and a fine fraction 36. The coarse fraction is subjected to gravity separation 16 and coarse particle flotation 20 to obtain a chrome concentrate and a PGM concentrate.
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Selective Control and Regulation of Mg Removal to …
Chromite processing residue (COPR) is a by-product of chromate production, generally containing less than 1% Cr(VI) and about 10% total Cr, belonging to hazardous waste, and an essential Cr resource. Here, we report the composition of the Cr host phases in COPR and the method for sufficient extraction of Cr from it.
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Environmental implications of one-century COPRs evolution in a …
The Stoppani factory manufactured chromium for more than one century, dumping millions of tons of Chromite Ore Processing Residues (COPRs) over decades. ... Selective extraction experiments confirmed a strong reactivity for Cr-bearing minerals as confirmed by concentrations as high as 375 mg L-1 of leached Cr VI.
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Selective Extraction of Chromium from EAF Stainless …
that the maximum extraction rate reached 98% at the optimal conditions. Liu et al. investigated the chromium leaching rate from chromium ore in concentrated KOH by catalytic oxidation using CuO as the catalyst.14) With the optimal reaction conditions, the leaching rate reached 98%. Thus far, investigations on the selective extraction of ...
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Deep Learning-Enabled Label-Free On-Chip Detection and Selective ...
Thus, real-time on-chip selective extraction of cell-laden hydrogel microcapsules from oil into aqueous phase is crucial to the further use of the microencapsulated cells/tissues. Contemporary extraction methods either require labeling of cells for their identification along with an expensive detection system or have a low extraction purity ...
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Recent Progress in Hydrometallurgical Processing of Nickel …
The selective extraction of nickel and cobalt over iron from an Indonesian limonitic laterite Fe(II) rich has been investigated using NAPL . During NAPL leaching, nitric acid acts as both lixiviant and oxidant, and the process is a dissolution-oxidation–precipitation mechanism. ... Microbial extraction of nickel from chromite overburdens in ...
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Selective Potassium Chloride Recognition, Sensing, Extraction, …
Chalcogen bonding (ChB) is rapidly rising to prominence in supramolecular chemistry as a powerful sigma (σ)-hole-based noncovalent interaction, especially for applications in the field of molecular recognition. Recent studies have demonstrated ChB donor strength and potency to be remarkably sensitive to local electronic environments, including redox …
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Processing of Chromite Overburden by Soda Roasting to
Sodium hydroxide leaching [13, 14] and the consequent hydrometallurgical extraction of chromate from the lean chromite ores have also been reported. ... In order to remove these impurities, the leach liquor is used for the precipitation at the selective pH values. Initial experiments were conducted to precipitate out the silica. The pH of stock ...
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Selective Flocculation of Chromite Tailings | SpringerLink
Odisha state is the major reserve of the chromite ore. Due to the extensive applications, high-grade chromite ore is getting depleted day by day. Now it is a challenge for the industry to utilize these low-grade ores and tailings. Several attempts were taken to upgrade the low-grade chrome ores and tailings using different gravity separation methods, magnetic …
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Selective Control and Regulation of Mg Removal to Enhance Cr Extraction …
Chromite processing residue (COPR) is a by-product of chromate production, generally containing less than 1% Cr(VI) and about 10% total Cr, belonging to hazardous waste, and an essential Cr resource. Here, we report the composition of the Cr host phases in COPR and the method for sufficient extraction of Cr from it.
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Leaching of chromite ore in concentrated KOH by catalytic oxidation ...
DOI: 10.1016/S1003-6326(17)60103-1 Corpus ID: 99706121; Leaching of chromite ore in concentrated KOH by catalytic oxidation using CuO as catalyst @article{Longjie2017LeachingOC, title={Leaching of chromite ore in concentrated KOH by catalytic oxidation using CuO as catalyst}, author={Li Longjie and Hao Du and Yang Zhang …
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A novel reductive alkali roasting of chromite ores for carcinogen …
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 …
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Sufficient extraction of Cr from chromium ore processing …
The efficacious treatment and resource utilization of the chromite ore processing residue (COPR) is important for chromate salt production. In this study, the leaching of valuable elements from ...
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Materials | Free Full-Text | Reactivity of Low-Grade Chromite ...
It indicates that in the case of the chlorination of chromite constituents, a selective separation of the obtained chlorides is feasible thanks to great differences in their vapor pressure in a selected temperature interval. ... N. Extraction des Métaux de Valeur des Concentrés de Chalcopyrite et de Chromite par Chloruration. Ph.D. Thesis ...
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Sufficient extraction of Cr from chromium ore processing residue …
Chromium ore processing residue (COPR) is a hazardous waste generated during the production of chromate. Currently, approximately 10% of Cr 2 O 3 cannot be extracted after chromite sodium roasting and remains in COPR, wasting valuable Cr resources. In this study, Mg was selectively removed by using (NH 4) 2 SO 4 roasting in combination with H 2 SO 4 …
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2chromite ore processing residue (COPR)
2 22removal from the Mg & Cr coexisting phases in COPR.For this experiment, under the 23optimal (NH4)2SO4 active roasting (80 mmol (NH4)2SO4, 800 °C, 2 h), 79.55% Mg was 24removed, and the Cr extraction rate in sodium roasting reached 95.39%.After Mg 25removal, spinel and diopside in COPR were converted to easily extractable (Fe,Cr)2O3 26and Cr2O3, …
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Selective Removal of Iron from Chromite Ore Overburden
An extraction of 85% nickel with 2–3% iron could be achieved at a temperature of 700°C when roasted for 15 mins, 25 wt% sulphuric acid and 20 wt% moisture in two stages.
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The Chromothermic Reduction of Chromite
of the chromite spinels. Structural dissociation of the spinels is a basic requirement for making the iron amen able to removal. This has been the subject ofconsiderable research effort on the use of selective reduction of iron oxides and subsequent leaching ofmetallic iron. Reduc tion has been attempted mainly with solid carbon, but also
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Study on Extraction of Iron From Chromite - Zhao - 2015 - steel ...
This work demonstrated the feasibility of extraction of iron from chromite by carbothermic reduction and hydrochloric acid leaching. A chromite concentrate containing nearly 52% of Cr2O3% is finally ...
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Preparation of Potassium Dichromate Crystals from the …
The chromite and sodium carbonate heated separately at 1000 C in the microwave oven (frequency: 2.45 GHz; power 1.5 kW) in order to study the ... from tailings, extraction of rare metals from ores and heavy metals [3–6]. The microwave is an electromagnetic wave, with the frequency of 0.3–300 GHz (wavelength in
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Selective extraction of neutral nitrogen compounds found in …
An extraction of up to 50% of the N-compounds was obtained in one step, whereas the sulfur concentration reduction was only 5%. The selectivity of the extraction process towards heterocyclic aromatic compounds and polyaromatic compounds using BMIm + Cl − was further emphasized by two-dimensional GC-MS analysis of the extracted compounds.
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Study on extraction of iron from chromite — Åbo Akademi
N2 - Research about extraction of iron from chemical-grade South African chromite by carbothermic reduction and hydrochloric acid leaching was conducted in this study. It was found that temperature had a remarkable effect on the extraction yield of iron and that the optimum experimental temperature was 1100 °C, which coincides with the ...
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