Bauxite reaction residue BRR produced from the poly aluminum chloride PAC coagulant industry is a solid acidic waste that is harmful to environment A low temperature synthesis route to convert the waste into water glass was reported Silica dissolution process was systematically studied including the thermodynamic analysis and the influence of calcium and aluminum on
The major element composition of the bauxite is dominated by elevated concentrations of SiO 2 TiO 2 Al 2 O 3 and Fe 2 O 3 and analyses of element mobility within the bauxite indicate that all elements except for Nb and Ni and to a lesser extent Cr are depleted relative to the immobile element Ti
They first leached the reduced bauxite residue after extracting pig iron using a solution of 1 M H 3 PO 4 at 30 40 °C to remove SiO 2 Fe 2 O 3 Al 2 O 3 and CaO Subsequently they used a solution of 35 40% NaOH at 230 260 °C to remove over 95% of Al 2 O 3 and SiO 2 from the slag
Bauxite residue is generated from alumina production in the alumina refining industry by the Bayer process which requires a large amount of land resource and causes serious environmental problems
A large quantity of residues is generated in the refinery process of alumina from bauxite ores It is estimated that 1 t of bauxite ore residues are generated per ton of alumina [1] and approximately 90 Mt bauxite ore residues are produced annually in the world [2] The bauxite ore residue is a kind of industrial waste and always stockpiled on land after dehydration
When processing low quality gibbsite kaolinite bauxites technologies that involve different methods of mechanical and chemical enrichment with the separation of a difficult to utilize fine kaolinite fraction for disposal are used Before production problems related to waste storage and disposal arise To solve the problem of utilization it is necessary to develop an
A novel process is proposed to extract alumina and silica from high silica bauxite without residue discharge 1 Introduction Silica is a major impurity in bauxite ores which is commonly present as quartz SiO 2 and phyllosilicate minerals such as kaolinite Al 4 [Si 4 O 10] OH 8 illite K x Al 4 Si 8−x Al x O 20 OH 2 and pyrophyllite Al 2 [Si 4 O 10] OH 2 1 2 When producing
Silicon is the main impurity in high silica bauxite [1] [2] [3] and causes scaling on plant surfaces while affecting the quality of alumina during alumina production using alkaline methods such as the conventional Bayer process [4] [5] [6] With the increasing demand for alumina refineries the utilization of low grade high silica bauxite has attracted substantial
The percentage extraction of SiO 2 and REEs was calculated based on the following equations 1 ε M % = γ × β α × 10 2 γ = m 1 m 0 × 100 where ε M represents the leaching ratio of SiO 2 and REEs %; γ is the yield of the leached residue %; α is the content of SiO 2 or REEs in original bauxite residue or iron removed bauxite
Bauxite is the main raw material of the alumina production industry especially the main source of aluminum metal industry [1] Depending on the difference of main alumina bearing minerals bauxites can be classified into three categories gibbsitic bauxite Al OH 3 boehmitic bauxite γ AlO OH and diasporic bauxite α AlO OH
On the Mechanism of Sodic Removal from Bauxite Residue and Bauxite Desilication Products BDP Using Acetic Acid Bauxite to Aluminum Advances Automation and Alternative Processes; The β cage is a six corner chopped truncated octahedron with either AlO 4 or SiO 4 tetrahedrons alternately arranged at each apex of the cage
Bauxite residue is generated from alumina production in the alumina refining industry by the Bayer process which requires a large amount of land resource and causes serious environmental problems
from the alkaline leaching process of the bauxite residue As shown by the XRD pattern in Fig 1 after pre removal of iron silica and alumina as well as other components from bauxite residue only perovskite CaTiO 3 and a small amount of brushite CaHPO 4 Æ 2H 2O were present Reagents Chemical acids of analytical grade such as phos
Materials The bauxite samples used in this work originated from Dengfeng city Henan province China After crushing and grinding a chemical analysis of the bauxite was performed by X ray Fluorescence XRF ZSX Primus II the results are listed in Table basic chemical composition of the sample as indicated in Table 1 are typical for a low grade bauxite
Bauxite is digested with sodium hydroxide at an elevated temperature of about 106 240 °C depending upon the quality of bauxite to extract alumina from it 97% has been reported with scope for better use for the non magnetic fraction in building material industry because of removal of iron and increase in percentage of aluminosilicate
Similarly for iron removal from bauxite iron reducing bacteria can be used Silicate bacteria aid in selective silica solubilisation to control alumina silica ratios SiO 2 CaCO 3 removal are discussed below Impurities like calcium and iron in the bauxite ores causes many processing problems for applications in manufacture of alumina
reactive silica content The contents are at least of 40% alumina and 5% of silica reactive [3 7] And the bauxite standard for feed of Bayer process are is grade of Al 2O 3 > 51% grade of SiO 2 < 7% and ratio of Al 2O 3/ SiO 2 > 10 [5] Bauxite in Tayan itself has different chemical compositions of Al 2O 3 and SiO 2 One of kind of bauxites
Afterward in tests designed by the Taguchi method the effect of parameters such as time process temperature HCl concentration and feed grain size on iron removal from bauxite by HCl leaching
Bauxite ore is the principal resource for aluminum production Bauxite ore is composed of aluminum based minerals like gibbsite Al OH 3 boehmite γ AlO OH and diaspore α AlO OH with auxiliary minerals such as hematite Fe 2 O 3 goethite FeO OH quartz SiO 2 rutile/anatase TiO 2 and kaolinite Al 2 Si 2 O 5 OH 4 There are three
