Abstract: New methods of purification and comprehensive utilization of phosphogypsum were experimentally studied.On the basis of physical testing of phosphogypsum samples，including particle size distribution，XRD mineral analysis，chemical analysis，and SEM morphology analysis，phosphogypsum was treated with low-cost ammonium bicarbonate，ammonia，and industrial by-product hydrochloric acid，and calcium sulfate（CaSO₄） was obtained by removing impurities.Meanwhile，by-product ammonium chloride was also got and carbon dioxide could be recovered.Then CaSO₄ was applied as raw material to prepare calcium sulfate whisker by hydrothermal method，so as to enhance the application value of phosphogypsum.Optimal conditions of phosphogypsum purification and hydrothermal method of calcium sulfate whisker were obtained by experiments，the morphologies of calcium sulfate and calcium sulfate whisker were analyzed by POM and SEM.Results showed that the experimental process route was technically feasible，the process equipment and operating conditions were simple，the mother liquor could be recycled，no‘three waste’ pollution，so it not only reduced environmental pollution，but also cut down the production costs.Therefore，it had good economic and social benefits.

Key words: phosphogypsum, purification, calcium sulfate whisker, hydrothermal method