Potassium Alum crystal 1. Al2(SO4)3K2SO4`12H2O 2. CAS NO. : 7784-24- ... , easily soluble in water, its water solution appears acid, lose crystal water and become white powder on heating. UseageIn the field ... Chemical Industries: Purification of water, paper making and glue spreading, painting, printing and dyeing, color lake and pigment, medicine producing, varinish ...