A METHOD FOR PRODUCING CALCIUM SULFATE BY USING SPENT CAUSTIC FROM CHEMICAL PROCESS

摘要

Provided is an environment-friendly method for producing calcium sulfate out of spent caustic that is discharged from a chemical process being performed in a petrochemical plant. The method for producing calcium sulfate(CaSO4) out of spent caustic comprises the steps of: inputting compressed air containing oxygen to the spent caustic produced from a chemical process to oxidize Na2S to Na2SO4 at 95-110deg.C; neutralizing the spent caustic that contains Na2SO4 to pH 2-10 by adding sulfuric acid or hydrochloric acid as a neutralizing agent; adding CaCl2 to the resulting solution to precipitate CaSO4; filtering and washing the precipitated CaSO4; and drying the CaSO4.