Continuous process for preparing sodium percarbonate

Abstract

A process of continuously crystalizing sodium percarbonate by the reaction of sodium carbonate with hydrogen peroxide using first and second reaction vessels includes the steps of: (a) continuously feeding a first feed solution containing sodium carbonate and a second feed solution containing hydrogen peroxide into the first reaction vessel, thereby to form therein a first slurry containing seed crystals of sodium percarbonate; (b) continuously discharging the first slurry from the first reaction vessel into the second reaction vessel while step (a) is performed; (c) continuously feeding at least one of hydrogen peroxide and sodium carbonate into the second reaction vessel while steps (a) and (b) are performed thereby to form therein a second slurry containing final sodium percarbonate crystals grown from the seed crystals; (d) continuously discharging the second slurry from the second reaction vessel while steps (a), (b) and (c) are performed; (e) continuously separating the second slurry into the final sodium percarbonate crystals and a mother liquor while steps (a), (b), (c) and (d) are performed; and (f) granulating the final sodium percarbonate crystals thereby to form a final product of sodium percarbonate. According to the process, it is possible to maintain particle size of the final sodium percarbonate crystals not larger than 100 .mu.m, thereby to efficiently produce sodium percarbonate granules having a satisfactory strength.