Bayer process


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Bayer process,

procedure for obtaining alumina from the aluminum ore bauxite. The alumina can then be used for various industrial purposes or smelted to provide aluminum. The first step in the process is the mixing of ground bauxite into a solution of sodium hydroxide. By applying steam and pressure in tanks containing the mixture, the bauxite slowly dissolves. The alumina released reacts with the sodium hydroxide to form sodium aluminate. After the contents of the tank have passed through other vessels where the pressure and temperature are reduced and impurities are removed, the solution of sodium aluminate is placed in a special tank where the alumina is precipitated out. The precipitate is removed from the tank, washed, and heated in a kiln to drive off any water present. The residue is a commercially pure alumina.

Bayer process

[′bī·ər ‚präs·əs]
(metallurgy)
A method of producing alumina from bauxite by heating it in a sodium hydroxide solution.
References in periodicals archive ?
The commonly used process for extracting bauxite is the Bayer process.
The project team which also includes the CSIRO, ETH Zurich, Hatch, IT Power, UNSW and the San Diego State University aims to develop the technologies and process knowledge to progressively integrate low temperature CST, solar reforming of natural gas, and high temperature CST into the existing Bayer process.
Billions of tonnes of this "red mud" sit in holding ponds around the world, an amount that will continue to increase as long as the Bayer process is used.
These include the formation of anionic polyacrylamide through hydrolysis, (17) the synthesis of sulfomethylated derivatives from the reaction of polyacrylamide with formaldehyde and sodium bisulfate, (18) the formation of aminomethylated polyacrylamide from the reaction of polyacrylamide with formaldehyde and dimethylamine (Mannich reaction), (19) and the generation of various derivatives by transamidation reactions including hydroxamated polyacrylamides used as a flocculant in the Bayer process.
For metal grade bauxite the aluminum content should be more than 40% and for chemical grade it may above 60% while most Bayer process plants use bauxite having alumina content greater than 40% however all the technical factors from mining to marketing are to be considered [8].
The available alumina and reactive silica results quoted are unbeneficiated based on low temperature caustic digest analysis (143AC), to simulate extraction by the Bayer process.
He explained the improved Bayer process step by step: identified a market problem, formed an economic value proposition and solicited feedback about the value proposition from parties throughout the value chain.
From the data obtained in this study, it may be safely said that bauxite of this area is suitable for extraction of aluminum by a small size Bayer Process Plant having annual feed of 1.
Stamixco LLC says the Bayer process also allows the mixers to be made and sold at lower cost.
The Bayer process uses caustic soda to digest the ore and solubulize the alumina from the bauxite as sodium aluminate.

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