(PDF) Chemical Processing of Bauxite: Alumina and Silica …
This Chapter provides an introduction to the Bayer process and how the mineral composition of bauxites affects the process variants and the principal parameters to be selected.
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R Lancashire Bauxite and aluminium production
The early work on non-bauxite sources was prompted by the potential disruption of bauxite supplies during World War II. At that time Germany for example, used domestic clay and 76 andalusite as a minor source of aluminium. After World War II, the aluminium industry relied almost entirely on bauxite as a raw material, and there was neither
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2. Digestion Technologies. The two main process efficiency requirements while processing any bauxite are: 1) Maximum possible alumina extraction and 2) Maximum possible and …
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Pre-desilication and digestion of gibbsitic bauxite with …
The Bayer process, which is the main process for pro- ducing alumina, involves the digestion of bauxites, solid- liquid separation, gibbsite precipitation, and calcination
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2. Digestion Technologies. The two main process efficiency requirements while processing any bauxite are: 1) Maximum possible alumina extraction and 2) Maximum possible and satisfactory desilication of sodium aluminate liquor at the digestion stage. Maximum alumina extraction ensures all the alumina
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Evolution of Tube Digestion Technology for Alumina …
Keywords: Tube digestion; single stream. Introduction Alumina refineries use primarily the "Bayer" process to extract alumina from Gibbsitic, Boehmitic or Diasporic bauxites. The Bayer process utilises a recirculating stream of caustic soda to extract the valuable alumina from the bauxite in four main processing steps.
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Section 4.8 Operational Report 1. The Bayer Process
The Bayer process is a continuous process which may be separated into four simple steps: hydrothermal digestion, where the bauxite is heated in hot caustic soda solutions to dissolve the aluminium bearing minerals; clarification, where separation of the aluminium-rich solutions and
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alumina minerals (digestion), and the crystallization of Al(OH) 3 (precipitation). The digestion process step highly depends on the mineralogical composition of the bauxite. The two major forms of digestion are: the low temperature digestion which was developed for the gibbsitic type
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Bauxite
Bauxite is converted to alumina in a refinery through a continuous four stage Bayer process involving: 1. Digestion – dissolving the bauxite's alumina content Finely ground bauxite is …
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R Lancashire Bauxite and aluminium production
The digestion process takes advantage of the solubility of amphoteric aluminium oxides to form a solution of aluminate ions, whilst the basic iron oxide, which does not
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consumption of raw materials for different bauxite is calculated, and the optimized digestion process is suggested considering suppressed the quartz attack and boehmite reversion. …
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Digestion Efficiency Improvement of Gibbsite-Boehmite …
Test results show that the bauxite contains 50% of alumina (gibbsite and boehmite) and 9% of silica (kaolinite and quartz). Its digestion efficiency is studied in detail with various digestion conditions such as temperatures, holding times and additives.
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In the treatment of boehmitic bauxites to achieve high target ratios, ideally requires: 1) fine milled bauxite, 2) optimal bauxite charge, 3) short residence times in digestion, 4) rapid settling in …
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(PDF) #45 Updated Improved Low Temperature Digestion (ILTD) Process …
The Improved Low Temperature Digestion (ILTD) Process was originally developed for processing gibbsitic type bauxites, that comprise nearly 90% of the World's bauxite reserves. This paper briefly reviews the development of the process concept, some
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consumption of raw materials for different bauxite is calculated, and the optimized digestion process is suggested considering suppressed the quartz attack and boehmite reversion. Keywords: Bauxite mineralogy, reactive silica, raw materials consumption model, digestion
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Digestion Efficiency Improvement of Gibbsite-Boehmite …
above 220 °C are needed in the digestion process. But at the relatively high digestion temperatures and long holding times, more quartz dissolves, which consumes alumina and caustic in the liquor. Therefore, the key to the study on the digestion process of gibbsite-boehmite bauxite is to ensure the complete digestion of boehmite and to ...
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Pre-desilication and digestion of gibbsitic bauxite with …
The effect of lime on the pre-desilication and digestion of gibbsitic bauxite in synthetic sodium aluminate liquor at different temperatures was investigated. The bauxite is comprised of gibbsite, aluminogoethite, hematite, kaolin, quartz, and minor boehmite. Lime increases the desilication efficiency of the bauxite during the pre-desilication process by …
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Digestion Efficiency Improvement of Gibbsite-Boehmite …
Test results show that the bauxite contains 50% of alumina (gibbsite and boehmite) and 9% of silica (kaolinite and quartz). Its digestion efficiency is studied in detail with various digestion …
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Pre-desilication and digestion of gibbsitic bauxite with
The Bayer process, which is the main process for pro- ducing alumina, involves the digestion of bauxites, solid- liquid separation, gibbsite precipitation, and calcination
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Modelling and optimization of digestion efficiency of …
Low-grade bauxites, when required, are used in the Bayer process by simple and inexpensive pre-processing to remove or reduce aluminosilicate mineral content [1, 2].
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Bauxite
four stage Bayer process involving: 1. Digestion – dissolving the bauxite's alumina content Finely ground bauxite is mixed with recycled hot caustic soda solution under pressure. This dissolves the alumina content of the bauxite and the solution is then cooled in a series of flash tanks. 2. Clarification – settling out and separating ...
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(PDF) Leaching Behavior of Lithium-Bearing Bauxite with …
The behavior of lithium-bearing bauxite in the digestion process was investigated, and the effect of digestion conditions on the extraction rates of lithium was studied. The (PDF) Leaching Behavior of Lithium-Bearing Bauxite with High-Temperature Bayer Digestion Process in K2O-Al2O3-H2O System | Nopia saputri - Academia.edu
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The Sandy Desilication Product Process Concept | JOM
The principal components of bauxite ores are aluminum-, iron-, and silicon-bearing minerals. In the Bayer process for recovery of alumina from bauxite,1 aluminum is dissolved into hot alkaline solution whilst iron is relatively insoluble. "Reactive silica" in the form of silicate minerals, such as kaolinite, typically dissolves and reprecipitates as sodium aluminum …
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(PDF) Enhanced conversion mechanism of Al-goethite in gibbsitic bauxite
Compared to typical Bayer digestion with Al-goethite containing gibbsitic bauxite as raw material, the red mud yield of reductive Bayer digestion decreases from 39.02% to 31.19%, and the grade of ...
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Bauxite
Bauxite is converted to alumina in a refinery through a continuous four stage Bayer process involving: 1. Digestion – dissolving the bauxite's alumina content Finely ground bauxite is mixed with recycled hot caustic soda solution under pressure. This dissolves the alumina content of the
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Section 4.8 Operational Report 1. The Bayer Process
The Bayer process is a continuous process which may be separated into four simple steps: hydrothermal digestion, where the bauxite is heated in hot caustic soda solutions to dissolve …
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AA02
In the treatment of boehmitic bauxites to achieve high target ratios, ideally requires: 1) fine milled bauxite, 2) optimal bauxite charge, 3) short residence times in digestion, 4) rapid settling in thickeners and washers, and 5) addition of liquor stabilizers to …
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Kinetics analysis for aluminum dissolution of west …
there are three minerals type of bauxite such as gibbsite, boehmite and diaspore (Bardossy and Aleva, 1990). Indonesia's bauxite mostly contains gibbsite and it requires relatively low digestion temperature for dissolving the alumina. Digestion is the core of Bayer process, which determine the yield of alumina. There are two main reactions
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initially reduces the bauxite to a size that the mill can handle, and then the mill delivers a product size suitable for the refinery feed. Milling of the crushed bauxite product (Table 2) takes place in caustic spent liquor at temperatures of ~ 75 °C and delivers a slurry for desilication and digestion. Bauxite is considered to be soft´
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KINETICS ANALYSIS FOR ALUMINUM DISSOLUTION OF WEST KALIMANTAN BAUXITE
Kinetics model was developed for aluminum dissolution of West Kalimantan bauxite based on shrinking core model. A series of digestion tests was carried out to study aluminum dissolution from the ...
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