Abstract

A stable, nonhygroscopic potassium monopersulfate composition comprising KHSO5, KHSO4 and K2 SO4 having a composition represented by a point within the closed curve of FGHIF of FIG. 1.A process for preparing a stable, nonhygroscopic potassium monopersulfate composition having the following formula:(KHSO5)x.(KHSO4)y.(K2 SO4)zwhere x+y+z=1 and x=0.48-0.64, y=0.15-0.37, and z=0.15-0.37 includes providing Caro's acid having a molar ratio of H2 SO5 /H2 SO4 of 1.6 or more and a water content of 40 to 65 weight percent, partially neutralizing the Caro's acid with a basic potassium compound to form a reaction mixture having a potassium to sulfur ratio (K/S) of 1.15 to 1.25 and a molar ratio of KHSO5 /(KHSO4 +K2 SO4) greater than 1.0, adding the reaction mixture to a solution having a molar ratio of KHSO5 /(KHSO4 +K2 SO4) greater than 2.5 to produce a final mixture having a molar ratio of KHSO5 /(KHSO4 +K2 SO4) of between 1.3 and 7.3, concentrating the final mixture in a vacuum crystallizer to produce a slurry, separating the slurry into a wet cake and a mother liquor, and drying the wet cake.An alternative process for preparing the triple salts includes using a triple salt of Caro's acid as the starting material, removing K2 SO4 from the starting material to produce a filtrate, neutralizing the filtrate, adding the neutralized filtrate to a KHSO5 -rich solution to produce a final mixture, crystallizing the mixture to produce a slurry, separating a wet cake from the slurry, and drying the wet cake.