WEBThe HallHeroult process is widely used in the extraction of aluminium. In HallHeroults process, pure Al 2 O 3 is mixed with CaF 2 or Na 3 AlF 6. This results in lowering the melting point of the mixture and increases its ability to conduct electricity. A steel vessel with a lining of carbon and graphite rods is used.
WEBJan 26, 2022 · Bauxite residue, the high alkaline and finegrained byproduct of Bayer process for alumina's production, is a material rich in numerous minerals and elements of high value and technoeconomical interest in high tech appliions such as rare earths, including scandium. Lately, the European Committee has characterized scandium as a .
WEBJun 1, 2016 · Leaching efficiency depends on the bauxite residue composition and process parameters, such as reagent type and concentration, retention time, temperature, and solid/liquid ratio [2,3,5,6,9,10]. ...
WEBAug 1, 2014 · The optimum conditions for the process parameters were obtained as: 675 0 C calcination temperature; 97 0 C leaching temperature; mol/l acid concentration; g/ml solidtoliquid ratio ...
WEBApr 1, 2024 · Due to drawbacks of the direct leaching route from bauxite residue, such as silica gel formation and low selectivity towards these valuable metals, a novel leaching process based on oxidative ...
WEBDec 12, 2016 · In this study, extraction of aluminum, iron, and titaniumbearing constituents from diasporetype bauxite ores was investigated by stepwise treatment consisting of predesiliion via alkalileaching of bauxite ore, extraction of alumina via Bayer process, and recovery of iron from red mud via magnetic separation. The pre .
WEBJun 1, 2015 · At this preliminary study, HbetTf 2N was applied on the direct leaching of Bauxite residue (Red. Mud), the solid residue generated from the Bayer process in alumina refineries worldwide. Bauxite ...
WEBJul 15, 2019 · In this study, an alternative twostage extraction process to acid roastingwater leaching was investigated to recover scandium from a Canadian bauxite residue. The process is called acid bakingwater leaching, in which bauxite residue is mixed with 98 wt% H 2 SO 4, baked in a furnace at 200–400 °C, and leached in water at ambient .
WEBJun 1, 2024 · Bauxite residue (BR) is a byproduct of bauxite refining using Bayer process for alumina production, which contains numerous valuable components: iron (Fe), aluminum (Al), and rare earth elements such as scandium (Sc). The main issue of previous research for the Sc extraction from BR was the low extraction efficiency or high Fe coextraction.
WEBMar 1, 2019 · During acid leaching of bauxite residue (red mud), the increase in dissolution of rareearth elements (REEs) is associated with a substantial codissolution of iron; this poses problems in the downstream processing ( solvent extraction or ion exchange). Six different slags generated by reductive smelting of the same bauxite .
WEBJun 24, 2019 · The sandy DSP process has the potential to significantly reduce costs associated with the bauxite residue sinterleach process by lowering energy and reagent requirements. The sandy DSP process uses conventional processing equipment and solution chemistry, which is fully compatible with the Bayer process. ...
WEBJan 1, 2023 · The leaching of highsilica bauxite using a mixture of NH 4 HSO 4 and H 2 SO 4 was analyzed using empirical SCM equations ((7), (8), (9)) to determine the optimal process by estimating the coefficient of determination (R 2). The following kinetic equation is applicable if the leaching process is limited by the surface reaction: (7) 1 – 1 ...
WEBSoda Sintering/Leaching Process Dried homogenized bauxite residue was sintered in muffle furnace with 50% excess of sodium carbonate (Na2 CO3, Sigma Aldrich, > % Purity) from stoichiometric amount required for sodium aluminate conversion, which amounted to 25 g Na2 CO3 for 100 g of bauxite residue. Sintering was performed in .
WEBThe leaching order of these materials are as follows: Goethite > serpentine > magnetite and hematite. The leaching kinetics were analyzed and this leaching process followed a shrinking core model controlled by a combination of .
WEBNov 1, 2020 · The acid baking water leaching process proves to be a promising technique as the first step of a potential nearzerowaste integrated process for the sustainable valorization of bauxite residue to ...
WEBThe results have been obtained as following: (i) Temperature play an important role in iron leaching from bauxite residue. Higher temperature is favor of Fe (III) leaching from bauxite residue. (ii) The leaching process is applicable to the intraparticle diffusion model and the apparent activation energy of model of leaching is found to be 17. ...
WEBJan 1, 2022 · The process combines carbothermic smelting, acid baking – water leaching, and thermal desulfation to efficiently extract the target materials from the bauxite residue without producing hazardous solid residues, while enabling the recovery and recycling of the major process reagents: CaO, SiO 2, and H 2 SO 4. Through .
WEBOct 15, 2023 · The REE patterns of Alrich layers were also associated with weathering and leaching process, the loss of most LREEs within bauxite ores (Fig. 9 A) and the strong negative correlation between (La/Yb)N ratios Al 2 O 3 contents (Fig. 8 H) indied REEs were also affected accompanying the accumulation of Al during the chemical weathing .
WEBJan 1, 2022 · A closedloop valorization process, combining carbothermic smelting and acid baking – water leaching was developed to recover scandium, aluminum, and iron from bauxite residue, a major side product of aluminum production. This process employs carbothermic smelting to recover 99% of the iron in the starting residue as crude metallic .
WEBOct 1, 2007 · The behavior of Al and Si in red mud in the leaching process of diaspore bauxite with NaOH submolten salt was investigated. The effects of reaction temperature, mass ratio of alkali to ore and ...
WEBJun 28, 2023 · The Bayer process is the main method of alumina production worldwide. The use of lowquality bauxites for alumina production results in the formation of a significant amount of technogenic waste—bauxite residue (BR). The Bayer reductive method is one possible way to eliminate BR stockpiling, but it requires highpressure .
WEBApr 4, 2017 · A full process was designed to recover scandium from bauxite residue. • Scandium is leached by sulfationroastingleaching and multistage leaching. • [Hbet][Tf 2 N] was used for the extraction of scandium from the leachate. • Separation between Fe and Sc was improved by reduction of Fe(III) to Fe(II).
WEBJun 1, 2020 · During water leaching, the watersoluble ions in bauxite residue were leached out. The CO 3 2−, HCO 3 −, Al(OH) 4 − and OH − were selected as the typical anions to evaluate leaching behavior of alkaline solid phases in bauxite residue. With the increase of L/S ratio, the leaching concentrations of CO 3 2−, HCO 3 − and Al(OH) 4 − .
WEBJun 13, 2014 · Request PDF | Leaching of rare earths from bauxite residue (red mud) | Bauxite residue or red mud is a waste generated during the Bayer process of alumina production. Its storage is a spatial and ...
WEBOct 1, 2016 · Semantic Scholar extracted view of "Study on the roasting and leaching behavior of highsulfur bauxite using ammonium bisulfate" by Z. Lou et al. Skip to search form Skip to ... In this study, we propose a novel temperatureprogrammed ammonium chloride (NH4Cl) roasting–waterleaching process to extract nickel (Ni), cobalt (Co), .
WEBApr 4, 2018 · Due to drawbacks of the direct leaching route from bauxite residue, such as silica gel formation and low selectivity towards these valuable metals, a novel leaching process based on oxidative ...
WEBIn the leaching method, bauxite ore is digested with a concentrated solution of NaOH that produces 'X'. When C O 2 gas is passed through the aqueous solution of 'X', a hydrated compound 'Y' is precipitated.
WEBNov 18, 2016 · Bauxite residue (red mud) with a high alumina content requires large amounts of fluxes during smelting, which increases the overall process cost, the energy consumption during smelting, and the acid consumption during slag leaching and decreases the throughput of bauxite residue in the smelting phase. Therefore, alumina .
WEBMay 15, 2015 · The leaching process with dilute HNO 3 was performed at pilot scale and optimized for the extraction of scandium from bauxite residue (OchsenkühnPetropoulou et al., 2002). Xue et al. (2010) found that at a reaction temperature of 90 °C and an L/S ratio of 3:1, over 80% of the scandium in bauxite residue could be leached by H 2 SO 4 .
WEBJul 15, 2019 · The current study put the emphasis on developing a novel and environmentally friendly waste valorization process, called "acidbaking waterleaching", to recover scandium from bauxite residue produced by the aluminum industry. In this process, bauxite residue is mixed with concentrated sulfuric acid, baked in a furnace at .
WEBOct 1, 2016 · The orthogonal experiment of highsulfur bauxite leaching process. Table 4 lists the schedule of the orthogonal test in which the three factors liquid–solid ratio (A), leaching temperature (B) and leaching time (C) are selected. Each factor has three levels to be optimized.
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