Bayer process zeolite

The Bayer process for the production of alumina uses caustie soda to extraet aluminium oxide from bauxite. The resulting solution of sodium aluminate also contains dissolved sodium silicate. The silicate is normally removed by allowing the aluminate and silicate to react to form precipitates of the zeolite structure having a eomposition of approximately NagAl6Si6024(0H)2. Slaked lime is added, when very low levels of silicate are required, to precipitate the silicate as cancrinite, which is removed, prior to the formation of the zeolite structures [31.19]. 

The other major raw material for zeolite production is the sodium aluminate solution. The production route to this important ingredient starts from bauxite minerals, for example, gibbsite [15,20,99,100,119,126,142,150-154]. The ore is extracted and purified via the Bayer process. The process encompasses the digestion of sodium aluminate by means of caustic soda and precipitation of purified aluminum trihydroxide [15,18,20,99,100,119,126,142,150-159]. 

Weber, H. 1962. Process for the production of sodium zeolite A. US3058805. Bayer AG. 

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