Process for producing high-purity alumina and hydraulic cement
AssigneeTatabanyai Szenbanyak
InventorsLaszlo Kapolyi, Geza Szentgyorgyi, Gyorgy Vamos, Jerzy Grzymek, Anna D. Grzymek, Stanislaw Bethke, Bronislaw Werynski
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Abstract
A low grade aluminum and silicon containing starting material is intimately mixed with limestone and the resultant mixture is fluidized. The fluidized mixture is preheated to a temperature of 700.degree. to 900.degree. C., then held at sintering temperature for 5 to 10 minutes. Aluminum may be recovered by extraction of the sintered powder so produced.
Claims10
In a process for recovering aluminum from a low grade aluminum and silicon containing starting material by sintering the starting material with limestone to produce a reaction product containing dicalcium silicate, cooling the reaction product whereby phase conversion of the dicalcium silicate causes the reaction product to disintegrate and subjecting the disintegrated product to alkaline extraction, wherein the improvement comprises the starting material and limestone are intimately mixed;
- the mixture of starting material and limestone is fluidized and preheated in the fluidized state to a temperature of 700.degree. to 900.degree. C. by heat exchange;
- then the preheated mixture is held at sintering temperature for 5 to 10 minutes in said sintering step.
Dependencies are inferred from the claim text.