METHOD OF TREATING GYPSUM FOR REDUCING ELUTION OF CONTAINED FLUORINE, AND GYPSUM REDUCED IN ELUTION OF CONTAINED FLUORINE

摘要

PROBLEM TO BE SOLVED: To provide a method of treating gypsum capable of economically and surely reducing the elution amount of fluorine from a gypsum containing fluorine up to a value of 0.8 mg/L or less of environmental quantity standards for soil by a simple work, and a gypsum obtainable by this treating method. SOLUTION: The gypsum containing fluorine is recovered after being aged for a required time in water in the presence of calcium hydrogen phosphate dihydrate to be an amount in the ratio of 1-5 pts.mass to 100 pts.mass of calcium sulfate dihydrate in the gypsum. COPYRIGHT: (C)2009,JPO&INPIT