WEBBauxite is the principal ore of aluminium. The impurities present in bauxite are SiO2, iron oxides and titanium oxide (T iO2). Concentration is carried out by heating the powdered ore with a concentrated solution of NaOH at 473 – 523 K and 35 – 36 bar pressure. This process is called digestion. Al2O3 is extracted out as sodium aluminate.
WEBJan 1, 2023 · The extracted Al in these studies exceeded 80%. However, the kinetics of the leaching process and the behavior of the major and trace elements have not been examined. Therefore, the leaching of highsilica bauxite from the Severoonezhsk deposit (μ Si < 3) using a mixture of NH 4 HSO 4 and H 2 SO 4 was investigated for the first .
WEBJun 1, 2024 · Bauxite residue (BR) is a byproduct of bauxite refining using Bayer process for alumina production, which contains numerous valuable components: iron (Fe), aluminum (Al), and rare earth elements such as scandium (Sc). The main issue of previous research for the Sc extraction from BR was the low extraction efficiency or high Fe coextraction.
WEBDec 1, 2012 · Both clinkers sintered by the real bauxite and simulated bauxite at 1350 °C when the molar ratio of CaO to Al2O3 decreased to were produced, the alumina leaching rates of which reached over ...
WEBJul 1, 2019 · During the Bayer process for alumina production, the molecular formula of the bauxite residue is approximately equivalent to Na 2 O·Al 2 O 3 · 2 ·nH 2 O. This means that 1 kg of SiO 2 in bauxite will produce 1 kg of Al 2 O 3 and kg of Na 2 O in bauxite residue. Thus, the extraction efficiency of alumina is low when processing low .
WEBMar 1, 2019 · During acid leaching of bauxite residue (red mud), the increase in dissolution of rareearth elements (REEs) is associated with a substantial codissolution of iron; this poses problems in the downstream processing ( solvent extraction or ion exchange). Six different slags generated by reductive smelting of the same bauxite .
WEBJan 1, 2023 · The leaching of highsilica bauxite using a mixture of NH 4 HSO 4 and H 2 SO 4 was analyzed using empirical SCM equations ((7), (8), (9)) to determine the optimal process by estimating the coefficient of determination (R 2). The following kinetic equation is applicable if the leaching process is limited by the surface reaction: (7) 1 – 1 ...
WEBDec 15, 2023 · 1. Introduction. Bauxite residue is an industrial solid waste with high alkalinity produced in the alumina refining process, which contains a variety of elements such as iron, aluminum, sodium, titanium, silicon, calcium, and magnesium (Fu et al., 2022; Shao et al., 2021).With the rapid development of the alumina industry, China has been .
WEBJan 6, 2022 · Some studies have already shown that the iron oxide content in nonrefractory grade bauxite can be decreased by an acid leaching process. 5, 820 Hydrochloric acid (HCl) in particular seems to be attractive for this appliion. However, in order to determine the possible leaching success, extensive tests are necessary, since a large number of ...
WEBApr 4, 2017 · A full process was designed to recover scandium from bauxite residue. • Scandium is leached by sulfationroastingleaching and multistage leaching. • [Hbet][Tf 2 N] was used for the extraction of scandium from the leachate. • Separation between Fe and Sc was improved by reduction of Fe(III) to Fe(II).
WEBJul 1, 2010 · The Al2O3 recovery, as well as the kinetic parameters, during the Bayer leaching process of different bauxite types strongly depends on their mineralogical composition. In this paper an attempt was made to develop a mathematical model which enables calculation of the Al2O3 recovery from boehmitediaspore or gibbsiteboehmite .
WEBDec 27, 2021 · The carbonate leaching of scandium from the landfilled bauxite residue (red mud) of the Bogoslovsky Aluminum Plant (Russia) and samples of red mud (RM) after alkaline pretreatment has been ...
WEBMay 15, 2015 · The leaching process with dilute HNO 3 was performed at pilot scale and optimized for the extraction of scandium from bauxite residue (OchsenkühnPetropoulou et al., 2002). Xue et al. (2010) found that at a reaction temperature of 90 °C and an L/S ratio of 3:1, over 80% of the scandium in bauxite residue could be leached by H 2 SO 4 .
WEBJun 1, 2020 · Bauxite residue, a byproduct of alumina manufacture, is a serious environmental pollutant due to its high leaching contents of metals and caustic compounds.
WEB1. Introduction. Depending on the composition and properties of the feedstock, alumina (Al 2 O 3) is produced by a variety of industrial processes [].Lowsilica bauxites are used worldwide for the production of alumina by the most energyeffective Bayer process, which is based on alkaline leaching with continuous regeneration of the solution by the .
WEBApr 4, 2018 · Due to drawbacks of the direct leaching route from bauxite residue, such as silica gel formation and low selectivity towards these valuable metals, a novel leaching process based on oxidative ...
WEBOct 10, 2002 · Published chemical analysis and leaching studies of bauxite residue focus on the concentration of Sc, because Sc represents 95% of REE's financial values found in BR (case of Greek Bauxite ...
WEBMay 30, 2022 · Bauxite Ore Processing: 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. Impurities are removed from bauxite by leaching a bauxite .
WEBJun 24, 2019 · The sandy DSP process has the potential to significantly reduce costs associated with the bauxite residue sinterleach process by lowering energy and reagent requirements. The sandy DSP process uses conventional processing equipment and solution chemistry, which is fully compatible with the Bayer process. ...
WEBMar 1, 2019 · Although conventional acid leaching with different mineral acids (, HCl, H 2 SO 4, HNO 3) can partially or fully extract REEs from bauxite residue, the leaching process is controlled by intraparticle diffusion as metals are transported from the solid phase to the solution through the cracks and pores present in the particles (Liu et al ...
WEBAccording to the literature, the leaching process depends on the type of bauxite residue, because mineralogical composition and morphological distribution of bauxite residue determine the best leaching agent. Hence, the REE recovery process from bauxite residue must be tailored for a given source 5. Most of the previous studies were focused .
WEBApr 1, 2021 · The leaching of boehmitekaolinite bauxite from the Severoonezhsk deposit mine (Arkhangelsk region, Russia) using a mixture of NH 4 HSO 4 and H 2 SO 4 was investigated for the first time. The bisulfate method, which combines the advantages of the acidic and alkaline methods, involves bauxite leaching, precipitation of ammonium alum ...
WEBJan 7, 2022 · 1. Introduction. Red mud (RM) is a solid waste generated by alkali (NaOH) leaching of bauxite by the Bayer process for alumina production [].More than one ton of RM is produced for one ton of alumina (Al 2 O 3), and over 150 Mt of RM is annually stored in landfills and sea [].The RM utilization degree is extremely low due to the high Na, Al, .
WEBJan 24, 2024 · The following are the examples of leaching process. Leaching of Bauxite. An example of a leaching process is the leaching of bauxite or Al 2 O 2 O with concentrated and heated sodium hydroxide. The concentrated NaOH here prefers to dissolve the aluminium contained in the provided bauxite, ...
WEBFeb 3, 2024 · This study presents a process for the simultaneous recoveryRecovery of metals from bauxite residueBauxite residue (BR) at relatively lower temperatures using H2 reduction to achieve zerowaste discharge (minimal waste generation) of BR. The proposed methodMethod...
WEBOct 1, 2016 · The orthogonal experiment of highsulfur bauxite leaching process. Table 4 lists the schedule of the orthogonal test in which the three factors liquid–solid ratio (A), leaching temperature (B) and leaching time (C) are selected. Each factor has three levels to be optimized.
WEBDec 1, 2010 · This article presents the results of experimental investigations of the leaching process kinetics for different types of bauxite: gibbsite, boehmite, diaspore, and gibbsite/boehmite and ...
WEBJun 28, 2023 · The Bayer process is the main method of alumina production worldwide. The use of lowquality bauxites for alumina production results in the formation of a significant amount of technogenic waste—bauxite residue (BR). The Bayer reductive method is one possible way to eliminate BR stockpiling, but it requires highpressure .
WEBJan 1, 2016 · PDF | On August 3, 1888 German Patent No. 43977 entitled "A Process for the Production of Aluminum Hydroxide" was issued**. ... The Bayer Process involved the pressure leaching of bauxite with ...
WEBMay 10, 2019 · Water leaching process is also recommended as a promising strategy to ameliorate the high salinity and alkalinity of bauxiteprocessing residue (Zhang et al., 2011) and high sodium (Na +) concentration has been reported in bauxiteprocessing residue leachate (Xiangfeng Kong et al., 2018a). Taking full advantage of the available water .
WEBDec 1, 2017 · The commercial Ga is the byproduct from Bayer liquor obtained from the bauxite leaching process and zinc residue generated by hydrometallurgical treatment of zinc concentrates (Zhao et al., 2012, Frenzel et al., 2016, Geological Survey, 2017). In the Bayer process, approximately 70% of the Ga is leached from the bauxite into the .
WEBFeb 3, 2024 · This study aims to obtain highpurity alumina from lateritic bauxite through hydrometallurgical processes by leaching bauxites with both sulphuric and hydrochloric acids at varying concentrations, temperatures, solid/liquid ratios, and process times.
WEBOct 15, 2023 · Bauxite resources in China are considerably large (Ling et al., 2015, Sun et al., 2018), while they are discovered mainly within Carboniferous and Permian strata of South China and North China cratons (Yu et al., 2019). ... Geochemistry characteristics and leaching process of the typical weathering profile within a karsitc depression revealed ...
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