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 washing step aluminum ...
At the same time, as a secondary resource, its aluminum content can reach 50%, which is close to that of mediumgrade bauxite; thus, it can be used as a substitute for bauxite resources. We propose a new method for extracting aluminum from fly ash via leaching. By designing the thermal reaction system of the molten brine, highpurity hydroxyl ...
The circulation liquid and lime (75% active CaO) for Bayer leaching were obtained from Guizhou, China. Methods. Three different AlFe recovery processes can be found in Fig. shown in Fig. 2, the LRS process means that the bauxite is firstly subjected to Bayer leaching, followed by magnetic roasting of red mud, and then, the roasted red mud would be magnetically separated for ...
The process of Leaching is used to concentrate the ore. NaAlO 2 + 2H 2 O → NaOH + Al(OH) 3. Serpek's process: This process is used when the bauxite ore contains a higher percentage of silica as an impurity. In this process, powdered bauxite ore is mixed with carbon (coke) and heated to 1473K in a current of nitrogen.
Gibbsitic bauxite from Australia was leached by hydrochloric acid in this work. Analysis on kinetics for the extraction of Al 2 O 3 was quantitatively studied. It was concluded that the hydrochloric acid leaching process of gibbsitic bauxite was controlled by chemical reaction. Moreover, the mechanism for the dissolution followed the equation ...
The lateritic bauxite hydrochloric acid leaching process showed that when the ore granularity was less than 55 μm, the liquid/solid ratio (L/S ratio) was 100:7, the leaching temperature was 373383 K, the leaching time was 120 min and the HCl concentration was 10%, both the leaching rates of Al and Fe were over 95% . But the hydrochloric ...
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 ...
In the process of recovering valuable elements from bauxite residue, the acid leaching process method is mainly used at present, which includes hydrochloric acid leaching, sulfuric acid leaching, nitric acid leaching, etc. Nitric acid is highly corrosive and cannot be connected with the medium of the subsequent extraction process, so most of them use hydrochloric acid or sulfuric acid leaching.
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 ...
Thus, Bayer process is economically unsuitable to process the bauxite resource with silica content greater than 8% by weight (A/S≤) . As to the bauxite with A/S of, the A/S in concentrate fed to the Bayer process can be increased by predesilication with flotation dressing [ 26, 27 ], roastingleaching process [ 28, 29 ], or ...
The ideal conditions for the leaching process was determined through response surface methodology (RSM) to be H3PO4 concentration of mol/L, L/S ratio of 11 mL/g and leaching temperature of 40 ...
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.
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 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.
In the leaching method, bauxite ore is digested with a concentrated solution of N a O H that produces X. When C O 2 gas is passed through the aqueous solution of X, a hydrated compound Y is precipitated. X and Y are N a [A l (O H) 4 ] and A l 2 O 3 ⋅ x H 2 O respectively.
It is the process in which ore is treated with aqueous alkali to form a soluble complex,, bauxite ore. Acid Leaching. In this process, the ore is treated with an acid solution. In other words, it is a process for the dissolution of metals using an acid solution. An example is the extraction of copper from oxide or sulfidebearing ore.
The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide) and was developed by Carl Josef, the most important ore of aluminium, contains only 3060% aluminium oxide (Al 2 O 3), the rest being a mixture of silica, various iron oxides, and titanium dioxide. The aluminium oxide must be further purified before it can be refined ...
In this process, bauxite residue is smelted at 1500 °C or higher in presence of a flux and a reductant to produce pig iron and slag. Alumina in the produced slag is mainly in the form of calcium aluminate that can be treated with Na 2 CO 3 solution. The leach residue generated from this process is known as gray mud.
Red mud (RM), also known as bauxite residue, is an alkaline solid waste byproduct derived in the extraction process of alumina from bauxite ore. With increasing demands for alumina, the global reserves of RM have reached billion tons in 2018, and it is estimated that an annual increase was approximately 200 million tons [1].
Bauxite residue (BR) is a hazardous industrial waste and also becomes an important reserve of rare earth elements (REE). An elegant process for achieving separation of REEs against silica from an ironremoved BR was established in this paper through selective leaching of silica with simultaneous enrichment of REEs.
The process consists of the following steps: calcination of bauxite, leaching of calcined bauxite in hydrochloric acid, filtration of residue, crystallization of A1C1 H 2 O, decomposition of AlCl H 2 O crystals to produce A1 2 O 3, regeneration of hydrochloric acid for recycle into the leaching step.
In order to explore the commercialized applications of the lowgrade bauxite in the refractory industry, a calcination integrated with acid leaching method was adopted to remove the potassium (K) and iron (Fe) from the diasporeillite (DI) type lowgrade bauxite. Following calcining the bauxite at different temperatures, the leaching parameters, including the sulfuric acid concentration ...
DOI: /materproc Corpus ID: ; The Efficient Use of Sulfuric Acid in Bauxite Residue Leaching article{Toli2023TheEU, title={The Efficient Use of Sulfuric Acid in Bauxite Residue Leaching}, author={Aikaterini Toli and Dimitrios Kotsanis and Maria Psoma and Danai Marinos and Panagiotis Davris and Efthymios Balomenos and Dimitrios Panias}, journal={RawMat 2023}, year ...
An example of the leaching process would be the leaching of Al 2 O 2 O (or bauxite) with a heated and concentrated solution of sodium hydroxide. In this example, the concentrated NaOH dissolves the aluminium present in the bauxite whereas the impurities such as Fe 2 O 3, TiO 2, and SiO 2, are not dissolved by the reagent.
Bayer process solution, in which a bauxite is subsequently leach ed for alumina extraction, and an alkaline solution with a concentration of 400 g L 1 Na 2 O, to c arry out similar investigations.
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.
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 ...
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.
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 ...
During the Bayer process, REEs Fe, Ti and other undissolved material along with remain unchanged. As a result rare earths end up in BR with an enrichment factor of approximately 2 comparing to the initialore [3]. Therefore, the aluminum industry throughthe Bayer process concentrates the critical metals found in bauxite into bauxite residue.
Verified by Toppr. Bauxite gets dissolved in hot concentrated NaOH but the impurities do not dissolve in this. So, the method of concentration used for bauxite ore is Leaching. Solve any question of General Principles and Processes of Isolation of Elements with:. Patterns of problems.
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 ...
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