RECYCLING OF WASTE GYPSUM BY EFFECTIVE SEPARATION USING ULTRASONIFICATION AND GRAVITY

摘要

PURPOSE: Provided is a method for recycling waste gypsum by removing impurities from waste gypsum effectively through ultrasonification and gravity separation. CONSTITUTION: The purification method of waste gypsum comprises the steps of: (i) milling waste gypsum, generated from desulfurization and production of H3PO4, HF, F, etc., in attrition mill, wherein the waste gypsum contains 70wt.% of gypsum and 30wt.% of impurities such as magnetite, galena, pyrite and quartz; (ii) cyclone separating gypsum particles(about 100micrometer) to separate magnetite, galena, pyrite; (iii) passing separated gypsum through spiral separator to remove remaining magnetite and pyrite, which results in good quality gypsum of 95% purity for use as gypsum board. The purity of resultant gypsum is further improved by applying ultrasonic waves(40-50kHz) to gypsum obtained from the step (iii) and removing heavy metal particles from gypsum by multi-gravity separator.