Introduction. Bauxite residue is a highly alkaline waste discharged from the process of alumina production. In recent years, the global industrial inventory is approximately 5 billion tons, with an annual increase of 200 million tons (Wu et al., 2020).Due to its high salinealkalinity, and potential environmental risk, the comprehensive utilization rate of bauxite residue is less than 10% ...
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The bauxite residue was derived from the Bayer process and deposited in dams with the dry disposal method. The bauxite residue disposal area was divided into two zones, and the effective storage capacities of the first zone and second zone were 4 million and 9 million m 3, respectively. The bauxite residue samples were collected from the ...
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The chemical process of bauxite formation is similar in both cases (clay is leached to aluminum hydroxides) but the source material and the general geological situation of the two types are different. The chemical reactions that constitute the lateritization process 5:
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Soilformation process is critical to ecological rehabilitation on bauxite residue disposal areas. In this study, a soil column experiment was taken to assess the dynamic variations of soilformation indicators in bauxite residue driven by the integration of waste solids and microorganisms. Results showed that the combination of waste solids and microorganisms significantly decreased the ...
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To systematically develop the REE recovery process from bauxite residue, ... China: Insights on conditions of formation and processes. J. Geochemical Explor. 133, 88102 (2013).
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The physicomechanical and technological properties of these bauxite vary widely depending upon the parent rock composition, mode of origin, geomorphological position, duration and age of bauxite formation. In the Bayer process the most important parameter that decides the economic importance is the quality of bauxite which again decides the ...
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The free silica leads to the formation of Bayer sodalite with important losses of sodium hydroxide and alumina in the muds (near to 30%) . The production process of Bayer alumina is shown in Figure 2. In the Bayer process, bauxite is leached with a hot solution of sodium hydroxide (NaOH) at temperature of 150240°C and at 16 atm pressure ...
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In the Bayer Process, the bauxite is washed in a hot solution of sodium hydroxide, which leaches aluminum from the bauxite. The aluminum is precipitated out of solution in the form of aluminum hydroxide, Al (OH) 3. The aluminum hydroxide is then calcined to form alumina, Al 2 O 3. Aluminum is smelted from the alumina using the HallHeroult Process.
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Bauxite is a natural product of weathering and occurs as a white to grey to reddish orangebrown crust at or near the Earth's surface in regions that have, or have had in the past, high rainfall. Bauxite is generally hard, heterogeneous in appearance and can be nodular, layered or massive.
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Thus, the contents of Al and Ti, which are mainly sourced from the continental basement, should be relatively stable during the whole formation process of bauxite. This is confirmed by the high correlation between Al and Ti in most bauxite deposits (, Ellahi et al., 2016; Mameli et al., 2007; Xiong et al., 2021; Yang, Huang, et al., 2019).
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However, the metallogenic mechanism of bauxite is still obscure due to the unclear formation process of the main ore mineral, diaspore. We conducted geological, mineralogical, δ 34 S pyrite, and insitu diaspore trace element analyses on the BaodeXingxian large bauxite deposit in the northern NCC, aiming to clarify the diasporeforming ...
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Wellreacted geopolymers with good compressive strengths (4458 MPa) were formed from highly alkaline residue from red mud (the residue remaining after extraction of alumina from bauxite by the Bayer Process) without the addition of strengthpromoting components, such as fly ash or ground slag, by adjusting the composition to an optimal SiO2/Al2O3 ratio of about 3 with silica fume. The ...
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Formation. Bauxite is a laterite, formed by the intense weathering of surface rocks. In the geosciences, lateritic bauxites (silicate bauxites) are distinguished from karst bauxites (carbonate bauxites). ... bulk of the world's bauxite production is processed into alumina (aluminum oxide) and then into aluminum. In the Bayer process, bauxites ...
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The second, La Compagnie des Bauxites de Guinée (CBG), is a decadesold company, coowned by the Guinean government and multinational mining companies, including Alcoa and Rio Tinto. This report ...
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Organic amendments addition is an effective measure to promote the soil formation process in bauxite residue. Organic amendments including biomass, manure and sewage sludge are effective amendments for accumulating organic carbon in bauxite residue (Courtney et al. 2013; Guo et al. 2022b; Xue et al. 2016). The humification of the residue by ...
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The formation of lateritic bauxite deposits require intense weathering conditions and is best developed in tropical climates. Lowgrade lateritic iron ore forms with the enrichment of Fe by chemical weathering/leaching. ... The paleogeological history establishes the process of nickel laterite formation. The laterite formed by intense chemical ...
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The formation of an amorphous phase and transformation to zeolite A were shown to occur at temperatures lower than 85oC by Barnes et al. [11,12]. Previously, formation of zeolite A as an ... (To the Chemical Process of Bauxite Digestion. Studies in system of Na2OAl2O3TiO2H2O) Metall, 25, (1971), 3, pp. 239250.
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A brief insight into the conventional Bayer bauxite digestion process demonstrates that during the low temperature digestion, gibbsite and clay minerals of bauxite gets dissolved, with formation of sodalite as one of the end reaction product. While the high temperature digestion results in boehmite and diaspore solubilisation that starts ...
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In addition, slaked lime (Ca(OH) 2) is typically added within the Bayer process to enhance extraction of the available alumina from bauxite and this can lead to the formation of many solid phase calcium hydroxides, carbonates and aluminates, such as TCA (tricalcium aluminate — Ca 3 Al 2 (OH) 12). These solids act as an alkalinity store and ...
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Fragmentation of homogeneous bauxite matrix with formation of Feoxide films and coatings around and including the isolated matrix parts in the CK4 horizon (Fig. 4), can also be interpreted as result of an in situ process, that took place either during bauxitization or diagenesis (Bárdossy 1982; see also Achyuthan and Fedoroff 2008; Yuste et ...
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Accelerating the process of soil formation in bauxite residue and converting the residues to a soillike medium are critical to determine success of revegetation on the disposal areas (Xue et al., 2021). During the soil formation process, studies on alkaline removal, aggregate formation and organic carbon accumulation are emphasized.
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Bauxites are residually enriched rocks, mostly composed of Alhydroxides (gibbsite, boehmite and diaspore), kaolinite, Feoxyhydroxides and Tioxides, which form from intense lateritic weathering of aluminosilicate protoliths. Lateritic weathering and bauxite formation are generally favored by largely humid, tropical and subtropical climates.
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Bauxite is used to produce alumina, which is then used to produce aluminum. Wastes can be generated at several points in the production process, including during the mining of the bauxite ore, and during the refinery production process. The refinery processes used to produce aluminum generates about 2 tons of solid waste for every 1 ton ...
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Beside the processing behaviour of the main constituents of bauxite such as hydrated alumina and silica minerals, the Chapter covers the impact of other constituents, such as titania, iron...
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Bauxite is the principal ore of aluminum. Bauxites vary physically according to the origin and geologic history of their deposits: some deposits are soft, easily crushed, and structureless; some are hard, dense, and pisolitic,
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The process of extracting aluminum from bauxite involves crushing and refining the mineral to produce alumina, which is then used to produce aluminum metal. The global demand for aluminum has driven the growth of the bauxite industry, with major bauxiteproducing countries including Australia, Guinea, Brazil, and China.
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The principal components of bauxite ores are aluminum, iron, and siliconbearing minerals. In the Bayer process for recovery of alumina from bauxite,1 aluminum is dissolved into hot alkaline solution whilst iron is relatively insoluble. "Reactive silica" in the form of silicate minerals, such as kaolinite, typically dissolves and reprecipitates as sodium aluminum hydrosilicate, known as ...
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Mineral genesis and oreforming process. Three stages of bauxite formation are recognized based on the mineralogy of studied samples: (1) weathering of regional sedimentary strata; (2) bauxite deposition; (3) second exposure of previously deposited bauxite caused by paleouplift.
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Formation. Bauxite is the most common aluminium ore. Bauxite occurs as a weathered cover or blanket, known as laterite or duricrust, over a variety of aluminabearing rocks. ... In almost all commercial operations, alumina is extracted from the bauxite by the Bayer refining process. The process, discovered by Karl Josef Bayer in 1888, consists ...
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The formation of Al(OH) 3 forms a protective layer. This formula suggest the formation of gibbsite, density g/cc leading to a molar volume of cc. ... What is an amphoteric oxide? What solution is used to extract aluminum from bauxite in the Bayer process?Is aluminum a more reactive metal than zinc towards oxygen? Why does aluminum not ...
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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 ...
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Lateritic bauxite formation. Laterite is formed when heavy tropical rainfall results in intense weathering of rock and soil. The chemistry of weathering silicarich rocks sees the relatively mobile elements such as calcium, sodium, potassium and magnesium being washed away, while the immobile metals including aluminium, iron, titanium, and ...
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However, its formation mechanism is still a matter of debate. In this study, the Taiping bauxite deposit, a representative large deposit in this area, was selected to carry out detailed mineral microanalysis and pyrite sulfur isotope analysis to further understand the metallogenic process of bauxite in this region.
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