The common raw material for aluminium production, bauxite is composed primarily of one or more aluminium hydroxide compounds, plus silica, iron and titanium oxides as the main impurities. It is used to produce aluminium oxide through the Bayer chemical process and subsequently aluminium through the HallHeroult electrolytic Process. On a world ...
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The effect of lime on gibbsite bauxite digestion is different from its effect on diaspore bauxite due to its different composition and digestion properties [15, 16]. In one report, gibbsite bauxite was digested by adding 1% lime at 145 °C, achieving a better digestion efficiency of %. However, excessive lime addition will lead to excess ...
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The impact of bauxite slurry pumping on the refining process such as bauxite dewatering, additional evaporation requirements etc. must be taken into account in the design of the alumina plant. ... (= bauxite residue [incl. sand] + lime products) maximum t/tA (dry basis): the bauxite residue ("red mud") leaving the refinery after ...
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The dominance of Ca in the sintering process is assigned to the excessive addition of lime. Depending upon the refining process adopted by the refinery, Al 2 O 3 ... Wu, Y.: Characterization of red mud derived from a combined Bayer process and bauxite calcination method. J. Hazard. Mater. 146(12), 255261 (2007) Google Scholar ...
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An improved lime sinter process based on the drysintering is proposed by adding Na 2 Ocontaining compounds to decrease CaO addition and increase alumina leaching property. The molar ratios of CaO to Al 2 O 3 and Na 2 O to Al 2 O 3 are and, respectively.
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The hydrogen reduction of bauxite residue lime pellets at elevated temperatures was carried out to recover iron and alumina from the bauxite residue in a new process route. Prior to the H 2 reduction, oxide pellets were initially prepared via the mixing of an industrial bauxite residue with fine calcite powder followed by calcination and high ...
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The process is based on smelting reduction of basic (steelmaking slags), acidic industrial residues (fly ash, bottom ash, etc.) and additives like bauxite, lime, etc. based on requirement. The process uses electrically heated ladle furnace or smelting reduction . This process can be used to produce fluxes of the required composition by treating ...
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The alkali methods for alumina extraction from byproducts of HAC can be classified into lime sintering process, limesoda sintering process, hydrochemical process, and hematite involved roastingalkali leachingBayer process. ... Teng W, Wang XG, Qin JG, Xu P, Li PC (2010) Alkali desilicated coal fly ash as substitute of bauxite in limesoda ...
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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 3 . The basis of the ...
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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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Introduction. Bauxite residue, or red mud, is a solid waste produced from the alumina refining of bauxite ore. Red mud is mostly collected from the Bayer process which uses sodium hydroxide to dissolve the aluminium silicate. Typically, about 1 to tonnes of red mud remains from the production of 1 t of alumina (Zhang et al., 2011).
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Lime can be used to overcome problems when using bauxites with specific and variable chemical and mineralogical characteristics. Although lime is extensively used when processing diasporic...
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Soda sintering or limesoda sintering process, began from L ouis Le Chatelier's work in 1855 in obtaining aluminum hydroxide (Al(OH) 3 ) from sintering bauxite with soda at around 1000 °C which
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The Bayer process is the principal method for production of alumina from bauxite worldwide. The modern version of the process (developed in the 1880's) still maintains
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Bayer process and sodalime sintering process are elaborated and compared. As a hybrid process, bauxite residue undergoes a reductive smelting process with lime addition in an electric arc furnace in order to generate aluminaenriched slag. This slag is subsequently treated with high
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The flotationBayer process has been widely applied in the alumina refineries, but it introduces large amounts of hazardous organic reagents and produces tailings totaling of about 25% of the initial bauxite ores in weight. 25,26 The lime Bayer process has been also employed to process a portion of highsilica bauxite, but it cannot ...
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Ferric bauxite, a type of bauxite with high hematite content, has yet to be commercialized. Direct reduction [1−2] can realize ferric bauxite comprehensive utilization; however, the sodium carbonate consumption in direct reduction is considerably higher than that in the ordinary bauxite processing technology [3]. Previous research
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Based on lime sintering method, a novel process of alumina production from lowgrade bauxite containing sulfur or fly ash is carried out in this paper. The phase of alumina transforms from 12CaO·7Al 2 O 3 (C 12 A 7) to 4CaO·3Al 2 O 3 ·SO 3 (C 4 A 3 S), whose alumina leaching property is better, through decreasing sinter temperature and time ...
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Bauxite residues (also known as 'red mud', 'Bayer process tailings' or 'bauxite process tailings') are generated from alumina production where bauxite is digested in hot NaOH solution via the Bayer process. 22 The production of 1 tonne of alumina generates between 1 and tonnes of bauxite residue. 23 Currently, the yearly global ...
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Lime is an essential reagent required in various process steps of the Bayer process, in which bauxite ore is converted into alumina (Whittington et al. 1997), as illustrated in Fig. is used for improving conversion of goethite to hematite and dissolution of boehmite and diaspore during digestion; control of liquor impurities such as silica, oxalate, titanium and phosphorous; minimising ...
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A material supplier from Belgium would like to produce limestone powder for his custome...
India is rich in various mineral resources and it is an important mineral processing market
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