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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Abstract The recovery of major components of bauxite residue by carbothermic reduction at °C and subsequent slag leaching in a Na3CO3(aq) solution is studied. Iron recovers primarily to pigiron and lime is added to tune the calcium aluminate slags towards the highly leachable mayenite phase. The concentration of aluminum in the leachate correlates well with the occurrence of ...
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The Bayer process simulation is based on the modelling of selected and defined unit processes and inputoutput parameters from the published literatures, described in the following section. In the Bayer process simulation, the bauxite ore, extraction liquor and lime addition are mixed and heated in digesters in the pressure leaching step.
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The Bayer process is the principal method for the production of alumina from bauxite worldwide. The modern version of the process (developed in the 1880's) still maintains the key steps of dissolution of aluminarich minerals into hot caustic solution, separation of the insoluble phases, followed by gibbsite precipitation and calcination of the gibbsite to alumina (Al 2 O 3).
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Bauxite residue is the industrial solid waste discharged from the production of alumina by bauxite, which contains a certain amount of ferric oxide in a reddishbrown color, so it is also called "red mud", and is a typical nonferrous metallurgical solid waste (Wang et al. 2018; Xue et al. 2022).The varieties of bauxite residue depend on the grade of the bauxite and alumina production process.
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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 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 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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Additionally, it shows an increase in yields of two points when the lime dosage is low, and between and 3% of the bauxite weight. Based on the mineralogical and chemical composition findings ...
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Lime addition in the Bayer process enhances the phase transformation rate of goethite and the digestion performance of alumina in highiron bauxite (Chen and Peng, 1998; Peter, 2017). However, there is no report on the promotion scale, especially for the highcalcium medium system.
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In Bayer process, low temperature treatment of bauxite generally applicable to gibbsite in the presence of a significant amount of boehmite (>3%), requires a temperature increase and the addition of an additive to improve the leaching conditions. This research is based on improvement of low temperature leaching conditions 108 °C and the addition of lime during the attack of some types of ...
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The mechanochemical processing of bauxite with lime has been investigated. The milling of bauxite and lime mixtures in an attritor mill resulted in the formation of an iron rich hydrogarnet phase in bauxite/lime slurries containing greater than 9% CaO. ... The role of lime in the Bayer process with less lime is to eliminate the harmful effect ...
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Milling: Several meters of rock and clay are removed by blasting, drilling, and bulldozers. The bauxite is then transported to the crushing and washing area, reducing the particle size and increasing the available surface area for the digestion stage. The material that is discharged from the mill is called slurry
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Bauxite residue is a highly salinesodic tailings material formed as a byproduct of the Bayer process for alumina production. In situ remediation of bauxite residue has the potential to provide an effective means for accelerated rehabilitation of residue storage areas. However, previous work has predominantly only used chemical and physical amendments to date, limiting rates of pH ...
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Overall typical composition of a bauxite residue is given in Table 2 and based on the process conditions and region, the bauxite residue composition is tabulated as Table 3 and 4, respectively. Next to the major elements like Fe, Al, Si, Ca, and Na, there are also valuable minor elements such as Ga, V, Zr, and rare earth elements (Evans, 2016).
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Therefore, the optimum lime addition in the digestion process of gibbsiteboehmite bauxite should be determined by tests. Mineral Composition Changes During Digestion The mineral compositions in the bauxite residues at 240 ℃ for different digestion times are shown in Fig. 5 .
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Diasporic bauxite is the major kind in China, characterized by highaluminum, highsilicon, low ratio of Al2O3 to SiO2 [1], complicated mineral compositions [2] and finely disseminated associations of aluminous minerals and silicate minerals [34]. Presently, to produce aluminum oxide in China is usually not Bayer process but sintering process ...
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To simulate the hydration process of bauxite tailings as supplementary cementitious material, the hydration kinetics of a calcination activated bauxite tailingslimegypsum ternary system was investigated. Hydration heat of the ternary system was measured at 50 °C by an isothermal calorimeter. Kinetics equations were used to simulate the hydration process of the ternary system.
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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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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 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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1. Introduction The Bayer process accounts for over 90% of the world's commercial production of alumina. The process involves digestion of bauxite in a caustic soda solution at temperatures ranging from 100 to 250 °C, depending on the form of alumina in the bauxite, gibbsitic, boehmitic or diasporic.
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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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