The Bayer Process. The Bayer Process, which is used by about 80 active plants worldwide, is the primary method of producing aluminum from bauxite. Bauxite ore is dissolved in sodium hydroxide, or lye, at a high temperature and pressure. Then, the alumina and bauxite ores are separated by washing out the waste (red muds or sands) from the alumina.
WhatsApp: +86 18203695377
The most commonly used methods for aluminium production are the Bayer process and the HallHeroult process. The Bayer process is used to produce alumina (Al 2 O 3) from bauxite and the HallHeroult process is used to produce molten aluminium from the year 1887, Karl Josef Bayer invented a method of extracting aluminium hydroxide from bauxite through Bayer processing.
WhatsApp: +86 18203695377
Precipitation 2. Desilication In the Bayer process the desilication of bauxite is an important step to maintain the alumina quality. It requires conversion of reactive silica of the bauxite into a nonsoluble sodalite complex (Sodium aluminium silicate or sodalite). The desilication can be carried out before digestion or after the digestion ...
WhatsApp: +86 18203695377
In the Bayer process, bauxite is digested with sodium hydroxide solution at high temperature and pressure producing alumina and generating the waste known as 'red mud' or 'bauxite residue' in large quantity. After the process, the residue which is alkaline in nature has pH of and is disposed of in red mud ponds.
WhatsApp: +86 18203695377
The bauxite ore, Bayer process materials before precipitation, mud residue, and sand residue are therefore of radiological interest, whereas the alumina product is Positional and personal monitoring data from bauxite mines and alumina refineries in Western Australia have been used to assess the abovebackground annual doses for the ...
WhatsApp: +86 18203695377
silica minerals in the gibbsite bauxite during the digestion process at high temperatures was also studied. It was determined that the phase transition of aluminogoethite is enhanced at 250 °C. By further raising the temperature and extending the digestion time, aluminogoethite transforms into hematite, from which more alumina can be recovered.
WhatsApp: +86 18203695377
• Digestion; • Clarification; • Precipitation; and • Calcination. A simplified process flow diagram of the Bayer process used at the Wagerup refinery is presented in Figure 6. Bauxite Grinding and Slurry Storage Bauxite is ground to less than mm particle size at the refinery, using semiautogenous
WhatsApp: +86 18203695377
Almost the entire metallurgical grade alumina is produced from bauxite using the Bayer process. The leaching conditions in Bayer process depend on various Aloxyhydroxide minerals/phases present in the bauxite. Among the various bauxite types, gibbsitic (trihydrate) bauxite is easiest to digest. Monohydrate (boehmitic and diasporic) bauxites need more stringent digestion conditions in terms of ...
WhatsApp: +86 18203695377
the dissolved metal as the "back" end. This is the essence of the continuous Bayer Process used by the industry today. Caustic liquor (a strong caustic soda solution) is the medium moving around the circuit. When bauxite is added, the aluminium dissolves and a "green" (or pregnant) liquor richer in aluminium is formed.
WhatsApp: +86 18203695377
To test this hypothesis, a set of digestion experiments were conducted using gibbsite, one of the major minerals in bauxite. Gibbsite was digested at various temperatures (50, 75, and 95 °C) in ...
WhatsApp: +86 18203695377
The Bayer process is a chemical process for refining aluminium hydroxide, Al(OH)3from bauxite; this aluminium hydroxide is subsequently calcined to produce alumina, Al2O3.
WhatsApp: +86 18203695377
In the Bayer process, bauxite ore is heated in a pressure vessel along with a sodium hydroxide solution (caustic soda) at a temperature of 150 to 200 °C. At these temperatures, the aluminium is dissolved as sodium aluminate (primarily [Al (OH) 4] −) in an extraction process.
WhatsApp: +86 18203695377
As shown in Figure 1, the source of energy to the Bayer Process is the Powerhouse. Energy is distributed essentially as steam to Digestion and Evaporation and electrical power to the refinery. The amount of energy required is determined by four interrelated factors: 1. Type of Bauxite. Trihydrate bauxite (low temperature digest or
WhatsApp: +86 18203695377
The Bayer process involves four steps: digestion, clarification, precipitation, and calcination. In the first step, bauxite is ground, slurried with a solution of caustic soda ( sodium hydroxide ), and pumped into large pressure tanks called digesters, where the ore is subjected to steam heat and pressure.
WhatsApp: +86 18203695377
The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide) and was developed by Carl Josef, the most important ore of aluminium, contains only 3060% aluminium oxide (Al 2 O 3), the rest being a mixture of silica, various iron oxides, and titanium aluminium oxide must be further purified before it can be refined into ...
WhatsApp: +86 18203695377
Compared to typical Bayer digestion with Algoethite containing gibbsitic bauxite as raw material, the red mud yield of reductive Bayer digestion decreases from % to %, and the grade of ...
WhatsApp: +86 18203695377
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
WhatsApp: +86 18203695377
An improved process for extracting monohydrate and trihydrate alumina from bauxite containing both forms of alumina. The slurry of bauxite is subjected to a first digestion in a first portion of spent liquor at conditions sufficient to extract the trihydrate. The liquor containing the dissolved trihydrate is separated from the slurry under conditions of temperature and pressure that are ...
WhatsApp: +86 18203695377
Very small differences in bauxite hardness or density, mainly through variability in the content of ironcontaining hardcap, can lead to an increased recirculating load. This also leads to a longer residence time, with the possibility of a buildup of a critical size inside the mill.
WhatsApp: +86 18203695377
Because the aluminum component in bauxite is digested in a 5 N sodium hydroxide solution, the purity of alumina produced by the Bayer process is approximately % with the remainder Na 2 O.
WhatsApp: +86 18203695377
The Bayer process, as it has become known, is used for refining bauxite to smelting grade alumina (aluminum oxide), the precursor to aluminium. Typically, depending upon the quality of the ore, between and tonnes of bauxite is required to produce 1 tonne of alumina. The Bayer process is a cyclic one and is often called Bayer cycle.
WhatsApp: +86 18203695377
Abstract. In the Bayer process, used for the production of alumina from the bauxite ores, there are frequent disturbances and a large number of interacting processes which incorporate considerable ...
WhatsApp: +86 18203695377
The major portions of the impurity enter the Bayer process through bauxite. Beyond the critical levels the impurities alter the kinetics of the process. Among the various impurities, organic carbon is the most prominent one that affects the precipitation operation and the product quality, depending on the level of organic with respect to the ...
WhatsApp: +86 18203695377
At the start of the process, the bauxite is finely ground and, with the addition of caustic soda, converted into a viscous suspension (chemists say: digested). The sus pension is pumped through the pipes of a reactor and heated up in stages to approx. 270 °C. The lye dissolves almost specifically as the temperature rises and under pressure.
WhatsApp: +86 18203695377
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
Copyright © 2023 GMC Co., Ltd. SiteMap
