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To co-extract vanadium, titanium, and chromium from vanadium slag, a cleaner process featuring oxalic acid hydrothermal leaching with synergy of Fe powder was proposed in this paper.


Calcification roasting-acid leaching of high-chromium vanadium slag (HCVS) was conducted to elucidate the roasting and leaching behaviors of vanadium and chromium. The effects of the purity of CaO, molar ratio between CaO and V2O5 ( n(CaO)/ n(V 2 O 5 )), roasting temperature, holding time, and the heating rate used in the oxidation-calcification processes were investigated.


The process of sodium roasting and water leaching is able to effectively extract vanadium (V) and tungsten (W) from spent SCR catalysts. To improve the efficiencies of V and W, different sodium additives were first investigated in the roasting process. The results revealed that the process of NaCl-NaOH composite roasting and water leaching ...


Various processes such as soda-ash roasting (Antony et al., 2001), acid leaching (Geveci et al., 2002, Zhao et al., 2014), alkali leaching (Xu et al., 2005, Zhang et al., 2010) and alkali fusion (Hundley et al., 1985) have been developed for the processing of chromite ores in order to produce sodium chromate (Na 2 CrO 4), which is the primary ...


We simulated the roasting process of chromium by mixing Cr2O3 and Na2CO3 to analyze the influence of chromium on roasting vanadium slag. Samples were characterized by XRD, thermal analysis and SEM ...


ABSTRACT Calcification roasting-acid leaching were conducted to investigate the extraction behavior of vanadium and chromium from high-chromium vanadium slag (HCVS). The conditions were optimized by response surface methodology (RSM). Results showed that when HCVS and CaO were mixed in m(CaO)/m(V2O5) of 0.62, then roasted from room temperature to 840 °C and maintained for 170 …


Vanadium exists as multivalent valences in high-chromium vanadium slag, and it is hard to leach out in low valence. Electro-oxidation technology has been applied to enhance the leaching process of calcium-roasting high-chromium vanadium slag. The effect of parameters that affect the leaching efficiency of vanadium including concentration of sulfur acid, current density, reaction temperature ...


produce sodium chromate in sodium roasting process.8,9) During the chromium extraction process, the recovery rate is controlled by the salt roasting step in which chromium species in high valence states, such as sodium chromate, are produced. These compounds are readily soluble in the sub-sequent leaching step. Therefore, oxidation of chromite ores


Reclamation of reactive metal oxides from complex minerals using alkali roasting and leaching – an improved approach to process engineering S. Sanchez-Segado, T. Makanyire, L. Escudero-Castejon, Y. Hara and A. Jha, Green Chem., 2015, 17, 2059 DOI: 10.1039/C4GC02360A


The common methods for leaching out vanadium and chromium were hydrometallurgical technologies, like sodium salt roasting-water leaching 16, calcium roasting-acid leaching …


The roasting parameters have been studied as a function of roasting temperature, roasting time and ratio of alkali, in which the roasting temperature is the most effective factor on the leaching rate of vanadium and chromium. Under the optimum condition, the leaching rates of V and Cr reached 95.8% and 97.6%, respectively.


Calcification roasting–sodium carbonate (Na2CO3) leaching process was carried out to separate chromium and vanadium efficiently from high chromium vanadium slag (HCVS). Then vanadium existed in the form of ammonium metavanadate (NH4VO3) after precipitation from the purified leaching liquid, and highly pure V2O5 was prepared, while chromium remained in the vanadium tailings in the form of ...


12%Traditionally chromium chemical extraction has been carried out with alkali and CaO roasting, which led to major environmental issues due to CaCrO 4 /Na 2 CrO 4 release. In this review we examine the physical chemistry of both the low- and high-temperature roasting processes, which oxidizes the Cr 3+ to Cr 6+ state.


· from the calcium roasting process is the residue of water leaching after mixing chromite, sodium carbonate (Na 2 CO 3), and dolomite and calcining at high temperatures.15 This residue contains a large amount of calcium and a small amount of iron, aluminum, chromium, etc.


Chromium (Cr) was concentrated as chromium spinel in the vanadium slag produced by pre-oxidizing vanadium-containing hot metal in Pan-steel in China. Due to the chromium-rich Hongge ores used, chromium concentration in this slag was much higher than that in common vanadium slags. To propose a process for effective Cr extraction from the slag, mechanisms of Cr oxidation in Pan-steel vanadium ...


An efficient process to utilize the industrial waste, chromium–containing vanadium tailings was proposed. • 91.51% chromium was extracted after soda roasting–water leaching, and 87.40% chromium oxide was prepared further.


Roast-Water Leach Process Highlights: Ongoing process work at TECMMINE in Lima, Peru has replicated, and improved upon, promising initial roasting …


Bottom ash (BA) is mainly composed of compounds of Al, Fe, Ca, and traces of rare earth elements (REEs). In this study, the selective recovery of erbium (Er) as REEs by means of sulfation–roasting–leaching–precipitation (SRLP) using BA was investigated. A pre-treatment process of sulfation and roasting of BA was developed to selectively recover REEs using ammonium oxalate leaching …


While the leaching ratio of chromium is 3.98%. During roasting process, vanadium is oxidized to acid-soluble CaV2O5, Ca2V2O7, and CaMgV2O7. After leaching, chromium mainly exists in form of chromohercynite (FeCr2O4) and chrome-manganese spinel (Mn1.5Cr1.5O4) in leaching residues.


Traditionally chromium chemical extraction has been carried out with alkali and CaO roasting, which led to major environmental issues due to CaCrO 4 /Na 2 CrO 4 release. In this review we examine the physical chemistry of both the low- and high-temperature roasting processes, which oxidizes the Cr …


However, there are only a few studies of elements' effects on the salt roast vanadium process with the addition of calcium (every 1% increase of CaO in slag would cause a 4.7%–9.0% V2O5 loss [18]). This study will investigate the effect of chromium on salt roasting to provide a theoretical basis for the


chromium leach from basalt - buromas-bureaustoelen.be. chromium in basalt stone . It is a basic building block of the construction industry (dimension stone) and the chief materials from which aggregate, cement, lime, . will chromium leach from basalt chromium mining equipment,chromium, reaction or by roasting and leaching process The chromium crusher is, Basalt Stone Contact …


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roasting chromium processing

Earlier researches reveal the optimisation of the process parameters on soda-ash roasting leaving behind the . The Effect of Chromium on the Roasting Process of . · Abstract: We simulated the roasting process of chromium by mixing Cr2O3 and Na2CO3 to analyze the influence of chromium on roasting vanadium slag.


Chromium - Wikipedia, the free encyclopedia. Chromium is a chemical element with symbol Cr and atomic number 24. ... by silicothermic or aluminothermic reactions, or by roasting and leaching processes.


Effective Extraction of Chromium from Chromite Ore China. Chromite Ore Beneficiation Process or Chrome Ore Mining Process means Extraction of Chromium from Chromite Ore and the gravity concentration solution has been proven that it is a cost effective solution for chromite ore process there are many mineral separators which can be used for chromite ore beneficiation process such as jig …


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J. Wen, T. Jiang*, M. Zhou, H.Y. Gao, J.Y. Liu, X.X. Xue, Roasting and leaching behaviors of vanadium and chromium in calcification roasting–acid leaching of high-chromium vanadium slag, Int. J. Miner. Metall. Mater. 25 (2018) 515-526. : " " 。


ground and roasted chromite ores. In the roasting process, insoluble trivalent chromium [Cr(III)] present in the ores oxidizes to soluble hexavalent Cr [Cr(VI)], which is then recovered by aqueous leaching for further processing (Burke et al., 1991). The technology dates back to 1845 and is still in


While for the roasting and leaching behavior of chromium, the leaching rate reaches a maximum at 8.48 pct in n(CaO)/n(V 2 O 3) of 5, and is lower than 1 pct at n(CaO)/n(V 2 O 3) of 0 to 2, which proves that almost all chromium remains at the leaching residue. All of above indicates that CaO tends to react with vanadium rather than chromium.


Under the optimum microwave roasting conditions (1 NaOH/NaNO 3 mass ratio, 450 ℃ roasting temperature, and 10 min roasting time), the leaching rates of vanadium and chromium were 94.11% and 90.81%, respectively. In the leaching process, the reaction mechanism for the water leaching process was proposed. The process showed that leaching time ...


Here, we review chromium resources and methods to leach out Cr such as calcium-roasting, sodium-roasting, acidic leaching, alkaline leaching and sub-molten technology. The crystal structure of ...


When the roasting temperature was in the range of 500–800 °C, the leaching efficiencies of vanadium and chromium increased sharply to maximum of 94.87% and 80.51% respectively, indicating that vanadium and chromium spinels in the vanadium-chromium slag reacted with NaOH and O 2 and converted sufficiently into leachable sodium salts in this ...


Calcification roasting–sodium carbonate (Na 2 CO 3) leaching process was carried out to separate chromium and vanadium efficiently from high chromium vanadium slag (HCVS).Then vanadium existed in the form of ammonium metavanadate (NH 4 VO 3) after precipitation from the purified leaching liquid, and highly pure V 2 O 5 was prepared, while chromium remained in the vanadium tailings in the ...


The extraction of vanadium and chromium from high chromium content vanadium slag by salt roasting and water leaching process has been investigated, which uses …


Chromium is mined as chromite ore. Globally this ore is available in India, South Africa, Finland, Zimbabwe, Kazakihstan and the Philippines. Commercially, chromium is produced from chromite using silicothermic or aluminothermic reactions. Roasting and leaching processes are also used. Chemical Properties