Bauxite is widely used to produce alumina. There are many bauxite resources with high iron content. These resources could not be processed and utilized efficiently due to the high concentration of iron (Fe). The alkaline leaching process has been proposed to remove iron from these bauxite resources. Therefore, in this study, the alkaline leaching process was employed, and the effects of sodium ...
Bauxite residue (red mud) is an alkaline waste derived from the industrial process for extraction of alumina from bauxite ore. Some bauxite residues contain considerable concentrations of critical metals, for example, rare earth elements. Lithium in red mud was also reported as a potential resource. In the current study, a Lirich red mud was leached using acetic acid to investigate the ...
Hall's process for leaching of alumina from bauxite: (1) Bauxite ore and sodium carbonate are fused toghether to convert aluminium oxide into soluble sodium metaaluminate. The insoluble residue contains the impurities of silica and iron oxide. The fused mass is treated with water.
The results indicated that leaching of bauxite is the rate controlling process. The activation energy was determined to be kJ/mole, which was characteristic for a chemically controlled process. ... The effect of particle size on leaching of bauxite was studied using different size fractions (100+150 mesh, 150+200 mesh and 200+270 mesh
The process of extracting aluminum from bauxite involves crushing and refining the mineral to produce alumina, which is then used to produce aluminum metal. ... Leaching: This process involves the removal of minerals from rocks through the action of water. In the case of bauxite formation, silica and other minerals are leached out of the rock ...
Because the water leaching process does not consume additional reagents, it is economical. Still, this process is timeconsuming because longterm leaching and repeated dealkalization are necessary for the water leaching process. ... Red mud which is a byproduct from Bauxite ores process has a strong alkali component contg. % of Na2O ...
Bauxite residue (BR), an alkaline industrial waste, is a major byproduct of the alumina production process known as the Bayer process. The Bayer process generates a byproduct known as bauxite residue (red mud). This residue was leached with sulfuric acid in a pilot plant of Mytilineos to recover scandium. Scandium was selectively recovered in pilotscale experiments using ion exchange.
1. Introduction. Red mud (RM) is a solid waste generated by alkali (NaOH) leaching of bauxite by the Bayer process for alumina production [].More than one ton of RM is produced for one ton of alumina (Al 2 O 3), and over 150 Mt of RM is annually stored in landfills and sea [].The RM utilization degree is extremely low due to the high Na, Al, Si, and Ca content because these elements increase ...
Bauxite residue (BR) is a well promising resource for critical metals, especially scandium (Sc), a rare and expensive metal with increasing applications in advanced technology. Greek BR seems to significantly favor a commercially viable recovery of Sc combining optimized leaching and advanced separation techniques. Leaching with mineral acids emerges as the dominant selection compared to other ...
In this study, a novel process has been developed to extract lithium as lithium phosphate from bauxite mine tailings, which includes: 1) leaching with mixed acid (H 3 PO 4 + H 2 SO 4), 2) leachate neutralization, and 3) Li 3 PO 4 preparation. Mixed acid was used to effectively leach lithium (Li) without roasting pretreatment, the Li leaching ...
In general, the lithium content in bauxite ore is negatively correlated with the alumina content,, the lithium content in bauxite decreases with increasing Al 2 O 3 content. 25,28 Lithium in bauxite tailings 27 can be recovered using acid leaching; however, this leaching process is not selective and the leachate purification process is ...
In this study, metal extraction from bauxite ore was carried out with a twostage leaching process. At the first stage, bauxite ore was leached under atmospheric conditions with oxalic acid, iron ...
Leaching is a process widely used in extractive metallurgy where ore is treated with chemicals to convert the valuable metals within into soluble salts while the impurity remains insoluble. ... Alkali leaching ( bauxite ore) Acid leaching ( sulfide ore) Chemistry. Leaching is done in long pressure vessels which are cylindrical ...
1. Introduction. Red mud (RM) is a waste generated during bauxite processing for alumina production. The most common method for bauxite processing is the Bayer process, where raw material is digested under high pressure by NaOH to obtain a pregnant sodium aluminate solution [].During highpressure leaching, nonsoluble elements such as iron, titanium, and refractory or precipitated during ...
Leaching is used for the purification of Bauxite ore. Leaching is a process that is used in extractive metallurgy. How bauxite ore is purified by chemical method? It can be purified by either Hall's process or Baeyer's process or Serperck's process. Here, Mond's process is used for refining the nickel metal and Liquation process is used ...
Primary aluminum production is achieved by the combination of two metallurgical processes: (a) the Bayer process, which refines bauxite to metallurgicalgrade alumina (MGAl 2 O 3), and (b) the HallHéroult process, which produces aluminum metal by electrolytically reducing MGAl 2 O 3 in a cryolite bath. Increasing the sustainability of both these processes and of the entire primary ...
To uncover the mechanism of REEs leaching process from bauxite residue in the H 2 SO 4 system (without microwave pretreatment), liquid samples were taken over time up to 60 min at all four ...
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 iron, which can be separated from slag that contains ...
The process involves baking of bauxite residue with sulfuric acid (12 mL/g, 120200 °C, 224 h) to generate metal sulfates and further decomposition of sulfates (except RE) at high temperatures (600800 °C) and water leaching to dissolve REEs [14,15,16,17]. The process is not costeffective due to the very low starting concentration ...
The study showed the change in the limiting stage of the alkaline leaching process after water treatment, with the activation energy growing from to kJ/mol.
Acid leaching. In order to recover scandium and other rare earth metals, red mud is often dissolved by leaching with acids. The investigations on acid leaching of scandium from bauxite residue were extensively carried out [51, 53, 78, 8993].Zhang et al. [] used HCl for leaching of scandium from red mud, and the optimum leaching condition was determined as HCl concentration of 6 mol·L ...
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 .
The calcification‑carbonation method is a novel technology recovering Na 2 O and Al 2 O 3 from bauxite residue through mineral transformation, which realizes the harmless treatment of bauxite residue simultaneously. It is mainly realized by two key transformation steps such as calcification transformation and carbonation transformation of the slag phase, and multiple wet process series steps.
The acid leaching reactions of the bauxite would be thermodynamically easy and completed. Under the conditions that ore granularity is less than −55 μm, the L/S ratio is 100:7, and the leaching temperature is 373383 K, the leaching time is 120 min and the concentration of HCl is 10%, both the leaching rates of Al and Fe are over 95%.
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