METHOD FOR MANUFACTURING SODIUM SULFATE, GYPSUM, ALUMINUM HYDROXIDE BASED ON SODIUM ALUMINUM SULFATE CAPABLE OF COST-EFFECTIVELY IMPLEMENTING MANUFACTURING PROCESSES WITH RESPECT TO POLYSILICON

摘要

PURPOSE: A method for manufacturing sodium sulfate, gypsum, aluminum hydroxide based on sodium aluminum sulfate is provided to prevent the generation of impurities by treating sodium aluminum sulfate(NaAl(SO_4)_2) based on ammonia and calcium oxide.;CONSTITUTION: Sodium aluminum sulfate is introduced into the mixture of water and ammonia in order to obtain sodium sulfate and aluminum hydroxide. The reactant is filtered to obtain a filtered solution. The filtered solution is reacted with calcium oxide under pH 6.5 or less and a reacting temperature of 60-90 degrees Celsius in order to obtain gypsum(CaSO_4·2H_2O). Ammonia gas generated from the reaction is separately collected and re-circulated. The sodium aluminum sulfate is obtained as a byproduct from a polysilicon processing process.;COPYRIGHT KIPO 2012