METHOD OF PROCESSING SILICATE RAW MATERIAL Russian patent published in 2002 - IPC

FIELD: technology of inorganic agents, more particularly preparation of highly dispersed silicon dioxide (which is analog of carbon white) and aluminium salts used in water purification processes. SUBSTANCE: raw material is decomposed with 5-30 % sulfuric or hydrochloric acid, and after separation of insoluble deposit, solution is dehydrated, the resulting product is leached, the resulting suspension is divided, deposit is washed and dried, raw material is decomposed at acid consumption rate of 75-120% of stoichiometric amount to react with acid-soluble raw material components, and solution is dehydrated at 80-300 C. Decomposition of raw material with acid having concentration of higher than 20% is carried out when cooling or in the presence of stabilizing additive. Leaching of dehydrated product is carried out with water or acidified solution. After separation of the resulting suspension, solution is neutralized with nepheline to attain pH of at least 1.5. EFFECT: increased specific surface of silicon dioxide particles, lower content of impurities and increased yield of silicon dioxide from 1 ton of raw material. 4 cl