Verfahren zur Herstellung von kristallwasserarmen Aluminiumfluorid

摘要

1283498 Crystallizing aluminium fluoride OSTERREICHISCHE STICKSTOFFWERKE AG 19 April 1971 [30 April 1970] 27117/71 Heading C1A Aluminium fluoride having no more than 1 mol water of crystallization per mol of AlF 3 is crystallized from aqueous solution at at least 120‹ C. and 2 atmospheres pressure. Desirably the temperature is no more than 200‹ C. and the pressure no more than 16 atmospheres. Suitable process times are 30 minutes to 3 hours. Seed crystals may be added to the solution and these should be anhydrous AlF 3 or contain up to 1 mol/mol water of crystallization. The residual liquor contains 2-5 g./l. fluorine. The AlF 3 may be prepared by the reaction of Al(OH) 3 e.g. as bauxite, or clay, with fluosilicic acid.