Of this the greatest concentration is in Guinea, where there are wellproven resources of approximately 25 billion tonnes. Most bauxite occurs close to the surface, with only 1 or 2 m of overburden. Typical deposits range in thickness from 3 to 15 m. ... The bauxite ore, Bayer process materials before precipitation, ...
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Bauxite residue (BR) is a caustic redcolored byproduct of the Bayer process for alumina (Al 2 O 3) extraction from bauxite ore, generated in a proportion ranging from to (alumina: BR). BR may have distinguished particle's size distribution varying from sand (+100 μm) to fine particles (−150 μm) depending on the bauxite origins.
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The present study uses the Bayer process solution, in which a bauxite is subsequently leached for alumina extraction, and an alkaline solution with a concentration of 400 g L 1 Na2O, to carry out ...
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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 ...
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The Bayer process is used for refining bauxite to smelting grade alumina (Al 2 O 3), the precursor to aluminium. The process was developed and patented by Karl Josef Bayer 110 years ago, and has ...
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Bayer's process for concentration of bauxite. Bayer's process is used to obtain pure aluminium oxide from bauxite ore. The bauxite ore is concentrated by chemical separation. Bauxite contains impurities like iron oxide and silica. The bauxite ore is powdered and heated with sodium hydroxide under high pressure in the furnace.
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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. In the beginning, the geographical pattern of the metal aluminum was extended with the investigation and exploitation of the large bauxite reserves in Western ...
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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 ...
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The Bayer process is the name for the hydrometallurgical extraction and refinement of alumina from bauxite. Bauxite ore is ground and then digested in highly caustic solutions at elevated temperatures.
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Typically, the Bayer process produces smeltergrade alumina of % Al2O3, starting from bauxite containing 30% to 60% Al2O3. The main objective of the Bayer process is to extract the maximum amount of aluminum from the bauxite at as high an aluminate concentration in solution as possible, while limiting any troublesome side reactions.
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In this study, extraction of aluminum, iron, and titaniumbearing constituents from diasporetype bauxite ores was investigated by stepwise treatment consisting of predesilication via alkalileaching of bauxite ore, extraction of alumina via Bayer process, and recovery of iron from red mud via magnetic separation. The predesilication results showed that the removal of silica reached % ...
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Austria 1888: Karl Josef Bayer first discovered the Bayer process (digesting crushed bauxite in strong sodium hydroxide solution at temperature up to 240oC. ... Dressing or Concentration of the Bauxite ore by Hall's method . The dressing is the process of extracting a metal from an ore in which gangue is removed and the ore is prepared for ...
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The ore quality determines the performance of the Bayer's process. ... The actual processing conditions within the digester, such as the caustic concentration, leaching temperature and pressure, and the operating costs, are greatly influenced by the type of bauxite ore. Ores with high gibbsite content can be processed at about 140°C ...
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Of the three major sources of gallium, Bauxite contributes about 50% and that is even obtained during the refining process of the bauxite ore. So countries with nonnegligible concentration of Ga, needs to undertake thorough investigation into the techniques for recovering Ga both in the Bayer liquor and the red mud in order to add more value ...
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Among environmental hot spots all over the world are the tailings of RM, generated during the digestion of bauxite ore with sodium hydroxide by Bayer process for the extraction of alumina. The term 'red mud' is used as a synonym for 'bauxite residue'. The residue generated is usually highly alkaline with pH about [1, 2].
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Solution Verified by Toppr The bauxite is purified by the Bayer Process. First the ore is mixed with a hot concentrated solution of sodium hydroxide. The N aOH will dissolve the oxides of aluminum and silicon but not other impurities such as iron oxides, which remains insoluble.
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"Bauxite Residue" (BR) refers to the insoluble solid material, generated during the extraction of alumina (Al 2 O 3) from Bauxite ore using the Bayer bauxite ore is treated with caustic soda, the aluminum hydroxides/oxides contained within, are solubilized, with approximately 50% of the bauxite mass being transferred to the liquid phase, while the remaining solid fraction ...
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The first step is to heat the bauxite ore to temperatures of 200°c along with a sodium hydroxide solution. This will convert the aluminium oxide to a solution of sodium aluminate. The silica will dissolve itself in the process. The chemical equation is. Al 2 O 3 + 2 NaOH → 2 NaAlO 2 + H 2 O.
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is the main ore of aluminium with silica (S i O 2), ferric oxide (F e 2 O 3) and titanium oxide (T i O 2) as impurities in it. ii. In this process, the bauxite ore is first crushed and then it is leached by heating with hot concentrated caustic soda (NaOH) solution under high pressure for 2 to 8 hrs at 140 to 150 ∘ C in a tank ...
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The basis of the Bayer process is an understanding of the characteristics of the sodiumhydroxide—sodiumaluminate solution relationship, namely its ability to keep sodiumaluminate in a dissolved state over a wide range of conditions, especially on the temperature and caustic soda concentrations.
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It is well known that the Bayer process is the main method to extract alumina from the bauxite in the world [19]. However, Bayer process is only suitable for the treatment of high grade bauxite ore. With the development of alumina production capacity, the resources of high quality bauxite are decreasing year by year [10, 11].
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Solution. In Bayer's process, the bauxite ore is first crushed and then it is leached by heating with hot concentrated caustic soda (NaOH) solution under high pressure for 2 to 8 hrs at 140 to 150 °C in a tank called a digester. Aluminium oxide, being amphoteric in nature, dissolves in an aqueous NaOH solution, forming watersoluble sodium ...
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The ore is first converted into pure aluminum oxide by the Bayer Process, and this is then electrolyzed in solution in molten cryolite another aluminum compound. The aluminum oxide has too high a melting point to electrolyse on its own. The usual aluminum ore is bauxite. Bauxite is essentially an impure aluminum oxide.
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It is one of the critical contaminants in the Bayer process. Its average concentration, ... It also may occur that that the bauxite ore forms lenses: for example, in Kolhapur district (West Coast, India) there are lenses of sub grade laterite of 12 km long 300400 m wide and 23 m thick. This type of bauxite ore is quasi floating inside ...
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Baeyer's process is used to leach Red Bauxite, which has Fe2O3 as the chief impurity. Serpeck's process, on the other hand, is used to leach White Bauxite, which has Silica as main impurity. Both are efficient for their respective ores. But Baeyer's process is more frequently used, as Bauxite, more often than not, is also a source of Gallium ...
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