METHOD OF PREPARING ALUMINIUM FLUORIDE Russian patent published in 2001 - IPC

FIELD: chemical industry. SUBSTANCE: aluminum containing stock comprises kaolin clays and concentrates, disten-sillimaniteandalusite rocks and concentrates, anorthosites, nepheline syenites, high- silica bauxites or other raw materials which include alumina. Said stock is mixed with ammonium hydrodifluoride or fluoride at weight ratio from 1:2.5 to 1:3.5. Mixture is heated to temperatures from 170 to 210 C and maintained in heated state till complete fluorination of cel rock-forming components to form loose powder-like cake from which, after sublimation of hexafluorosilicate, hexafluorotitanate and ammonium fluoride in reducing or inert medium at least 400 C aluminum fluoride is prepared as nonvolatile residue. In order to prepare highly pure aluminum fluoride from alkali or calcium enriched alumosilicate rocks and minerals, second fluorination is carried out under the same conditions followed by sublimation. EFFECT: more efficient preparation method. 2 cl, 3 ex