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 ...
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Alumina (Al 2 O 3) is the raw material used to produce aluminium with a high temperature electrolysis process. It is mainly obtained by leaching an aluminacontaining ore known as bauxite. The most common process used to obtain alumina from bauxite is the one developed in 1887 by Bayer (Bayer, 1888, Bayer, 1894).
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Bauxite residue, known as red mud, is a byproduct of alumina production using the Bayer process. Currently, its total global storage amounts to over billion tons, including about 600 million tons in Russia. The total global storage of red mud occupies large areas, leading to environmental damage and increasing environmental risks. Moreover, it contains a significant amount of sodium ...
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Red mud, also referred to as bauxite residue, is the largest process waste produced during alumina production from bauxite ore by the Bayer method. Approximately 12 tons of red mud are produced for every ton of alumina produced 1. Global red mud manufacturing is anticipated to be 200 million tons annually.
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In 2015, the US Geological Survey estimated that over 95% of bauxite was converted to alumina, with the remainder going toward a variety of products such as abrasives, chemicals, proppants, and more. The primary approach to transforming bauxite ore to alumina is known as the Bayer Process.
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Aluminum Precipitation and Alumina Preparation. NH 4 HCO 3 solution (2 mol/L) was added to the leaching solution to adjust the appropriate pH value to precipitate aluminum in the form of Al(OH) precipitation conditions were carried out in the process of precipitation with the pH range of 59, precipitation temperature range of 30°C80°C, and precipitation time range of 30 min ...
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Concentration of Rare Earth Elements (Sc, Y, La, Ce, Nd, Sm) in Bauxite Residue (Red Mud) Obtained by Water and Alkali Leaching of Bauxite Sintering Dust May 2020 Minerals 10(6):500
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There are three primary methods for recovering alumina from aluminum ore such as Bayer process, sintered Bayer process and Pedersen process (Safarian and Kolbeinsen, 2016 ). The summary of these processes are listed in Table 1.
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Red mud, also referred to as bauxite residue, is the largest process waste produced during alumina production from bauxite ore by the Bayer method. Approximately 12 tons of red mud are produced ...
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bauxite and the red mud obtained by the alkali fusionwater leach ing method from this bauxite (RMF) and the mechanism of the process were presented in our previous article [36].
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A silicon modulus of enriched bauxite units was obtained. As a result of the autoclave leaching of gibbsitekaolinite bauxite after a twostage enrichment, the maximum extraction of alumina into solution was %. The yield of red mud during the processing of bauxite enriched and calcined at 950 C was %. During the autoclave
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Abstract In view of the shortcomings of traditional comprehensive utilization of high iron bauxite resources to produce alumina, such as high energy consumption and long process flow, this paper proposed a doublecycle process for alumina production. As a main component in highiron bauxite, iron(Fe) has adverse effect on the recovery of aluminum. Removal of iron is essential for recovery of ...
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In terms of price, scandium is the most valuable rareearth element in bauxite residue. This research discusses the effectiveness of scandium extraction from the bauxite residue through pressure leaching in sulfuric acid solution. The method was selected to obtain high scandium recovery and leaching selectivity to iron and aluminium.
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In this paper, a novel process is proposed to extract Al 2 O 3 and SiO 2 from highsilica bauxite without residue discharge, that is, sintering bauxite with Na 2 CO 3 followed by twostep leaching with water and sulfuric acid. The effects of the sintering parameters on the process were investigated, and the phase transformations during ...
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The specific process included pressure leaching by hydrochloric acidextraction separation of leaching solutiondirect pyrolysis of aluminum chloride solution to produce alumina. As shown in Fig. 1, first, the highiron bauxite was treated by acid leaching, and the solution containing aluminum chloride and ferric chloride was obtained.
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More than 90% of the world's commercial manufacture of alumina is obtained by hydrochemical sodium hydroxide extraction of bauxite through the conventional Bayer process.
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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 Dimis Kotsanis and Maria Psoma and Danai Marinos and Panagiotis Davris and Efthymios Balomenos and Dimis Panias}, journal={RawMat 2023}, year ...
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During the digestion process of the Bayer method, lithium and gallium in bauxite will enter into the sodium aluminate solution (Tang et al. 2020; Xu et al. 2018 ), which will return to the digestion process for recycling after the precipitation of aluminum hydroxide from the decomposition of crystal species.
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Experimental Method. In this study, the recovery of precious metals from bauxite ore was examined by a twostage leaching process. The stages of this process were Stage I: Removing iron to a large extent and revealing the solubility conditions of titanium by treating the bauxite ore with oxalic acid, Stage II: Determining the recovery conditions of aluminum from the residue obtained after the ...
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On refining bauxite by Bayers method, pure aluminium oxide is obtained which is also called alumina. In this method, bauxite powder is taken and concentrated (4 5 %) and sodium hydroxide solution is added and then heated in a closed vessel at 4 3 3 K temperature and 5 to 6 bars of pressure, for 6 to 8 hours, so that aluminium oxide present in ...
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The Bayer process is the main process applied to obtain alumina from bauxite ore. The mineral is dissolved using sodium hydroxide in digesters, which obtain sodium aluminate in solution and a solid phase called red mud; the two are separated by the clarification process [ 1, 2 ].
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The 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.
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produce highly purified and fine alumina, some alternative on leaching and precipitation processes were studied. These due to leaching process tends to predetermine the rate of recovery and the purity of alumina whereas a very effective precipitation process can be applied to produce fine size of alumina powder.
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In the Bayer Process to obtain alumina from bauxite, for each tonne of alumina produced, it generates tonnes of residue known as red mud [].The major chemical components of red mud are aluminum, iron, sodium, titanium and silicon; however studies have confirmed the presence of different valuable metals, such as scandium, yttrium and other rare earth elements [2,3,4,5,6].
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Based on the above technical route, > 96% SiO 2 and 97% Al 2 O 3 in highalumina coal gangue was extracted, respectively. 26 In addition, > 95% of silica by reduction roasting simulated CFBderived coal fly ash with Fe 2 O 3 can be dissolved in alkaline solution and the mass ratio of alumina to silica in the leached residue can increase from to above 20. 25 However, the silica leaching ...
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The Pedersen process is a method to produce alumina from Alcontaining sources, and it is a more materialefficient method than the current commercial Bayer process, since the formation of bauxite residue (red mud) is avoided, and the bauxite can be holistically consumed. The smelting reduction (SR) part of the Pedersen process yields pig iron and a calcium aluminate slag, and the latter is a ...
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A silicon modulus of enriched bauxite units was obtained. As a result of the autoclave leaching of gibbsitekaolinite bauxite after a twostage enrichment, the maximum extraction of alumina into solution was %. The yield of red mud during the processing of bauxite enriched and calcined at 950 °C was %.
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The Bayer process produces alumina from the bauxite ore, and the HallHéroult process leads to the dissolution of the alumina powder into cryolite batch to produce the metal aluminum. ... (OH) 3 obtained in the Bayer process is easier than do for aluminum salt like aluminum chloride (AlCl 3), obtained by acid leaching of nonbauxites ...
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The obtained desilicated bauxite was subjected to atmospheric leaching at 120 °C in a strong alkali solution (350 g L−1) or highpressure leaching at 160220 °C using the Bayer process mother ...
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