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high silica bauxite have been reviewed by Smith 2024 He categorized options into three strategies reduce reactive silica input modify the process to produce lower soda DSP and recovery of soda from residue this paper relates to the third strategy Treatment of BR with sulphurous acid SO 2 absorption can
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During the Bayer process the sulfur in high sulfur bauxite first enters the solution in the form of S 2− then the S 2− is gradually oxidized into various forms of high valence Sulfur S 2 O 3 2− SO 3 2− SO 4 2−
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Chapter 2 Production and Processing of Aluminum A high silica content of the bauxite is undesirable because insoluble sodium aluminum silicate will form causing losses of caus tic soda and alumina which increases input material costs Energy consumption is an other consideration The economical operation of the Bayer process requires the
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Semantic Scholar extracted view of Mechanochemical treatment of high silica bauxite with lime by P McCormick et al Semantic Scholar extracted view of Mechanochemical treatment of high silica bauxite with lime by P McCormick et al Skip to search form Skip to main content Skip to account menu Semantic Scholar s Logo Search 204 893 911 papers from all fields of science Search Sign In
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The process stages are 1 Milling The bauxite is washed and crushed reducing the particle size and increasing the available surface area for the digestion stage Lime and spent liquor caustic soda returned from the precipitation stage are added at the mills to make a pumpable slurry 2 Desilication
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The Bayer Process which continues to be the most economical method of manufacturing alumina can be schematically summarised in a flow chart and involves the following operations mining dissolution of the alumina at elevated temperatures addition of flocculants precipitation of pure Gibbsite regeneration of the solutions for recycling
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The principal process for modern bauxite requires smelting in a rotary kiln under a salt cover The salt slag is processed and reutilized later Other methods of processing bauxite such as smelting it in a hearth furnace or an induction furnace need little or no salt and less energy but are reserved for high grade scrap
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A process for removing silica from bauxite is disclosed The method includes the step of mixing bauxite with a caustic liquor to form a mixture and to dissolve and stabilise at least a substantial part of the reactive silica from the bauxite The caustic liquor is selected to have a high caustic concentration and a high alumina content Read More
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kaolinite or reactive silica content of bauxite the more red mud will be generated [3 8] High grade bauxite contains up to 61% Al2O3 and many operating bauxite deposits typically referred as non metallurgical grade are well below this occasionally as low as 30 50% Al2O3 Because the desired product is a high purity Al2O3
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The process chain has to be improved from the bauxite mining and processing up to the refinery and smelter removal of the high silica particle size range Reactive and Non Reactive Silica in Bauxite Ore from West widely used in mineral processing because of its high selectivity
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For a boehmitic or diasporic bauxite undergoing high temperature refining the silica input would typically be the total silica content of the bauxite The H2O % input At present the H 2 O % input has little impact on the CFR price
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Through the addition of soda and metal oxides coupled with also a possible reductive stage of iron by adding carbon the aluminum bearing minerals is then transformed into leachable sodium aluminate phase while suppressing reactive silica formation This will also allow ease of the introduction of leachates back again into the Bayer circuit
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Bauxite is first reduced through crushing and grinding usually in a portion of spent liquor at ∼ 60 °C Silicate minerals principally kaolinite start to dissolve in the spent liquor 1 3Al2Si2O5 OH 4 18NaOH → 6Na2SiO3 6NaAl OH 4 3H2O
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A process of dissolution Severoonezhsk deposit boehmite kaolinite bauxite by hydrochloric acid as well as the processes that occur during open air calcination were investigated A dehydration process has been studied and the basic phase transformation temperatures were identified Temperature and time of calcination influence on bauxite dehydration speed were determined It is shown that
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Sep 15 2021The present alumina prices will also put pressure and only bauxite with high available alumina and low reactive silica may survive in the competition China is undoubtedly the biggest consumer of bauxite and some alumina refineries have been built in the recent past based on imported gibbisitc bauxite of Guinea According to Antaike the
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High silica bauxites detailed process review process selection High Silica Bauxite Processing 2 Strategy One Beneficiation bauxite grades and the importance of research into economic ways of processing of high Effects of Mineral Admixtures Virtual Cement and Concrete Silica fume is modelled as one although beneficiation can be utilized to separate out the
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Bauxites that have high levels of silica SiO 2 go through a process to remove this impurity Silica can cause problems with scale formation and quality of the final product 3 Digestion A hot caustic soda NaOH solution is used to dissolve the aluminium bearing minerals in the bauxite gibbsite böhmite and diaspore to form a sodium
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Silicon bearing minerals first react with alkali entering into the solution in the form of potassium silicate [ 25] and then react with sodium aluminate solution to form potassium silicate hydrate entering into red mud in the high temperature digestion process of a K 2 O Al 2 O 3 H 2 O system Figure 5
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Bauxite produces 60 120 million tons of toxic red mud annually during its processing to alumina Thus in this work the modeling of the bauxite processing process to reduce quantity of red mud produced and with low alumina content was envisaged
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The caustic liquor is selected to have a high caustic concentration and a high alumina reserves of bauxite include vast quantities of ore which at present are sub economic due to high levels of reactive silica that cause expensive loss of caustic soda during Bayer processing PDF Reduction of Reactive Silica from Bauxite Alkali leaching of silica from activation roasted high
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silica removing from bauxite malta T22 09 16 00 00 silica removing from bauxite malta bau ite beneficiation process for removal of silica silica removing from bauxite malta primaryteachers May 23 2024 In view of beneficiation action of bauxite removal of maximum silica content from the feed ore is removal of silica content that are active in nature Chat With
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A process for removing this kaolin comprises contacting the bauxite with sodium hydroxide solution to form a mixture and subjecting the mixture to intense ultrasonic irradiation to cause cavitation this can be carried out at temperatures below 100° C This enhances both the dissolution of kaolin and the precipitation of sodium aluminium silicate
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1 Introduction Scope This document will critically review existing and potential processes for the processing of high silica bauxites High silica bauxites are usually considered to be those with reactive silica contents in excess of ∼ 8% by weight of the bauxite reactive silica is defined later in this paper Cited by 200[PDF]Get price
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Sintering process This method is suitable for treating low grade ores with high silicon content It requires that the Al2O3/SiO2 is 3～5 or so and the Fe2O3 content is below 10% In modern industry the sintering process is alkali lime sintering process The bauxite is mixed with certain soda ash and lime or limestone
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Aug 12 2022The magnetic separation process is as follows crush the raw bauxite ore to less than 5mm heat it with 25% coke at 780℃ for hours grind it then separate it with a magnetic separator to get iron concentrate and high grade raw materials for alumina Chemical beneficiation for bauxite
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World reserves of bauxite include vast quantities of ore which at present are sub economic due to high levels of reactive silica that cause expensive loss of caustic soda during Bayer
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A primary objective of the beneficiation process is to reduce the silica content in the ore as the latter indied the presence of high silica and low alumina management and control of silica in the bayer process some residual reactive silica in the bauxite feeding digestion which tends Of High Silica Bauxitehigh silica bauxite processing MiningDec 16 2024· ATF 06 04
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Integrated processing of non bauxite ores using ammonium hydrogen difluoride was studied The kinetics of sintering of the raw material sublimation of ammonium hexafluorosilicate and formation of aluminum fluoride and alumina were described The rate constants and activation energies of the reactions were determined
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A process for the removal of reactive silica from a feedstock to the digestion step of the Bayer process for the manufacture of alumina in which a the feedstock is contacted with a caustic liquor under process conditions which result in dissolving and stabilizing at least 50% of the silica into solution at a level of at least 3 gpL and without significant precipitation from solution of
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A study on local bauxite was conducted at Mineral Research Centre Ipoh to produce highly purified fine alumina Al 2 O 3 powder by using Bayer process as a basis The study was conducted on a local bauxite from Johor The raw material being classified having the specific gravity of and the major constituent of mineral was identified as
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