Continuous process for preparing sodium percarbonate

In a process of continuously crystallizing sodium percarbonate by the reaction of sodium carbonate with hydrogen peroxide using first and second reaction vessels, the process comprising the steps of:

• (a) continuously feeding a first fed solution comprising sodium carbonate and hydrogen peroxide and a hydrogen peroxide solution 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 wherein residence time of said first slurry in said first reaction vessel is not longer than 5 minutes;
• (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, the final sodium percarbonate crystals having a particle size of less than 100 .mu.m;
• (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;
• (f) continuously recirculating said mother liquor into the first reaction vessel while steps (a)-(e) are performed;
• and
• (g) granulating the final sodium percarbonate crystals thereby to form a final product of sodium percarbonate.