PROCESS FOR PRODUCING AN ALKALI METAL HYDROALUMINATE

摘要

The method comprises leaching a raw material containing aluminium oxides and an alkaline metal while obtaining the alkaline solution which is then desiliconized and concentrated by evaporation, the alkaline solution with a molar ratio of the alkaline metal oxide and aluminium oxide Me2O:Al2O3 of 1.1-1.7 being the subject of that concentration by evaporation. The concentration by evaporation is effected at a temperature of 120-150C up to a concentration of the alkaline metal oxide of 350-400 g/l. After concentration by evaporation the solution at a temperature of 95-150C is subjected to crystallization on a moving filtration surface having a temperature of 10-95C so that a rapid crystallization of the product and its separation from the mother liquor takes place on the filtration surface. The resulting mother liquor is returned for the leaching of the raw material.