METHOD OF KYANITE CONCENTRATE RECYCLING Russian patent published in 2014 - IPC C22B21/00 C22B3/10 C01F7/00 

FIELD: chemistry.

SUBSTANCE: kyanite concentrate undergoes hydrochloric acid treatment with acid concentration 15-25%, solid to liquid ratio of 1:4-8 and temperature 80-95°C for 0.5-2.0 hours with separation of aluminosilicate residue. Residue is mixed with ammonium hydrodifluoride in weight ratio 1:3-4. Obtained mixture is subjected to grinding until coarseness of particles constitutes 60-250 mcm in amount not less than 90%. Ground mixture is heated to 240-270°C and kept in heated state for 3-5 hours until complete fluorination of components with cake formation. After that, high temperature case is processed at high temperature at 780-820°C for 4-6 hours with removal of volatile hexafluorosilicate, hexafluorotitanate and ammonium fluoride and obtaining aluminium-containing product. Method ensures reduction of content of silicon dioxide admixture in aluminium-containing product to 0.0001% and lower.

EFFECT: increased degree of aluminium oxide extraction from kyanite concentrate with high content of aluminium oxide in target product.

3 cl, 4 ex