Name the following elements : (i) A trivalent metal used to make light tools. (ii) A monovalent nonmetal present in fluorspar. Baeyer's process is used to concentrate bauxite ore to alumina. Give balanced chemical equations for the reaction taking place for it's conversion from bauxite to alumina.
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Details of the Bayer process and related chemical issues for alumina production have been summarized in literature (Adamson et al., 2016). Bauxite residue waste has limited practical applications. The volume and composition of the generated waste depends on the quality of the bauxite ore, refinery design, and process conditions.
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Bauxite ore is the world's main source of aluminum. Bauxite is a rock formed from a reddish clay material called laterite soil and is most commonly found in tropical or subtropical regions. Bauxite is primarily comprised of aluminum oxide compounds (alumina), silica, iron oxides and titanium dioxide. Approximately 70 percent of the world's ...
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Solution. (1) The chief ore of aluminium is Bauxite Al 2 O 3 · 2 H 2 O from which aluminium is extracted. (2) The process of concentration of bauxite is done by Bayer's process. (3) In the electrolytic reduction of aluminium, alumina is added to cryolite because it lowers the fusion temperature of the electrolytic bath in the extraction of ...
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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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Scandium extraction from the Greek bauxite residue has been demonstrated at an industrial pilot plant at MYTILINEOS. This work comes as the result of the H2020 SCALE collaborative research project. By combining sulfuric acid leaching and IIVI SelectiveIon Recovery (SIR) technology, a 22 wt% Sc concentrate has been produced from the Greek Bauxite Residue that contains 70100 mg/kg Sc.
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Keeping the above characteristics in view, several west coast lateritic bauxite mines of India employ dry crushing−screening process to bring down silica content from the metallurgical grade bauxite [].Recently, a bauxite mine of Guinea known as AGB2A has also adopted the dry beneficiation procedure to cut down silica from about 7% to below 3%, to make this one the best metallurgical grade ...
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Answer NCERT Solutions CBSE CBSE Study Material Textbook Solutions CBSE Notes Bauxite is concentrated by: A) Chemical method B) Roasting C) Magnetic separation D) Froth flotation process Answer Verified + views
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In aluminum processing: Extraction and refining. .from bauxite is a twostep process: refining bauxite to obtain alumina and smelting alumina to produce aluminum. Bauxite contains a number of impurities, including iron oxide, silica, and titania. If these impurities are not removed during refining, they will alloy with and contaminate the ...
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It is the process of heating the concentrated ore in a limited supply or absence of air at a temperature not sufficient to melt the ore. ... Write the chemical formula of the ore. Answer. Bauxite [Al 2 O 2 O] Question 6(2018) Name the process by which impure ore of aluminium gets purified, by a conc. soln. of an alkali.
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The Bayer process is used for refining bauxite to smelting grade alumina, the precursor to aluminum. Typically, depending upon the quality of the ore, between and tonnes of bauxite is required to produce 1 ton of alumina. The Bayer process involves the digestion of crushed bauxite in the concentrated sodium hydroxide (caustic) solution at
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As the minerals are weathered they gradually breakdown into various forms of hydrated aluminum oxide, Al 2 O 3 .xH 2 O, known as bauxite. The bauxite is purified by the Bayer Process. First the ore is mixed with a hot concentrated solution of sodium hydroxide. The NaOH will dissolve the oxides of aluminum and silicon but not other impurities ...
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Control the Bayer Process. Red bauxite ore is transformed in the Bayer process to white alumina powder. This is the raw material for the electrometallurgical extraction of Aluminum metal. The yield of the Bayer process is not simply related to the Aluminum grade in Bauxite that is determined by chemical analysis.
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Zhang et al. used a twostage acid leaching process to extract titanium from bauxite residue using the nature of titanium insolubility in lowconcentration HCl. First, the bauxite residue was leached directly with a low concentration of HCl (5 mol/L is preferable), followed by H 2 SO 4 with a mass fraction of 92%, under the conditions of the ...
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The Bayer process is a chemical process for refining aluminium hydroxide, Al(OH) 3 from bauxite; this aluminium hydroxide is subsequently calcined to produce alumina, Al 2 O 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 ...
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The process is demonstrated in the following examples: Leaching of alumina from bauxite. The primary ore of aluminium is bauxite. Impurities such as SiO 2, iron oxides, and titanium oxide (TiO 2) are common. Heating the powdered ore with a concentrated solution of NaOH at 473523 K and 3536 bar pressure is used to concentrate it.
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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 called a digester. Aluminium oxide, being amphoteric in nature, dissolves in an aqueous NaOH solution, forming watersoluble sodium aluminate.
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Bauxite residues from alumina production. Aluminium production consists of two key stages: The first is alumina refining (Bayer process), which involves the generation of alumina from bauxite ore; the second stage is aluminium smelting (HallHéroult), the process of transforming alumina into Most of the world's alumina is produced using the Bayer process, although minor volumes ...
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Under the leaching conditions of Al and Li of an acid concentration of 60%, a liquidsolid ratio of 4 mL/g, a reaction temperature of 100 °C and a reaction time of 3 h, the highest leaching rates ...
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The bauxite is purified by the Bayer Process. First the ore is mixed with a hot concentrated solution of sodium hydroxide. The NaOH will dissolve the oxides of aluminum and silicon but not other impurities such as iron oxides, which remains insoluble. The insoluble materials are removed by filtration. The solution which now contains the oxides ...
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The REEs present in a bauxite ore end up in its bauxite residue during the Bayer process . The REE concentrations in the Jamaican bauxite residue is ppm [ 28 ]. The average concentration of REEs in Greek karst bauxite residue is ca. 1000 ppm [ 12 ].
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The process used for the concentration of sulphide ore.froth floatation process 6. The process of heating the concentrated ore in the absence of air, such that temperature is not sufficient to melt the orecalcination 7. The process of heating the concentrated ore in the presence of air to a high temperature.roasting. 8. An ore of aluminium ...
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The Bayer Process was patented in 1888 in Germany by the Austrian chemist, Karl Joseph Bayer [].The simple chemistry of the process is that the hydrated forms of aluminum in bauxite, readily dissolve in heated caustic (NaOH) solutions (the DIGESTION step, see Chap. 4).The advantage is that nearly all of the minerals in bauxite containing other metallic ions do not dissolve and so can be ...
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The iron oxide in bauxite ore is present as hematite or goethite; silica as clay; and free quartz and titania as leucoxene or rutile. Bauxite is the principal ore of aluminum which is one of the most important nonferrous metals used in the modern industry. It is also an essential ore for refractory and chemical industries.
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The ore is dug out from the opencast mines and contains aluminium oxide. The bauxite ore is purified to yield a white powder from which aluminium is extracted. The process of its extraction is done by electrolysis. Usually, bauxite ore is heated in a pressure vessel along with a sodium hydroxide solution at a temperature of 150 to 200°C.
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Bauxite is a sedimentary rock mineral that is the primary source of aluminum. It is formed through the weathering of aluminumrich rocks in tropical and subtropical regions. The name bauxite is derived from the French village of Les Baux, where it was first discovered in 1821 by geologist Pierre Berthier. Bauxite is typically found in layers beneath a few meters of overburden, which can vary ...
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Bauxite residue is generated during the Bayer process of alumina recovery from bauxite ore. The chemical compositions of bauxite residue are associated with the alumina process and the raw bauxite ores. ... In the process of changing acetic concentration from to mol/L, the loss of lithium was stable around %. However, further ...
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Bauxite (Fig. ) is formed by surface weathering of clay rocks around the tropical region and composer of aluminum oxide (Al (OH) 3 ). It contains 15%25% aluminum and only ore used for commercial extraction for aluminum. The bauxite occurs as nearsurface layers and usually mixed with clay minerals, iron oxide, and titanium dioxide.
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PROCESS DESCRIPTION: BAUXITE MINING. Bauxite is the principal ore of alumina (Al 2 O 3 ), which is used to produce aluminum (Al). It is composed of hydrated aluminum oxides, hydrated aluminosilicates, iron oxides, hydrated iron oxides, titanium oxide, and silica. It contains mixtures of various minerals such as gibbsite, boehmite, hematite ...
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The iron recovery ratio, Fe2O3 content in iron concentration and the bauxite dissolution ratio of each process were investigated. Moreover, the optimizations of the leaching, roasting and magnetic separation conditions were studied. Results indicate that the RSL process should be an advisable order to recover both alumina and iron.
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