Abstract: The high efficiency utilization of phosphogypsum is a problem needing to be solved in phosphate and compound fertilizer industry in China.The preparation of widely used and high value added calcium sulfate whiskers is one way of solving that.The experimental results indicate that，it is unable to get calcium sulfate whiskers with uniform morphology and high aspect ratio from phosphogypsum under hydrothermal condition，due to the influence of impurities，such as P，Si，Fe，and Al. Via the acid pretreatment，most of the impurities in phosphogypsum can be removed，then through hydrothermal-roasting process，anhydrous calcium sulfate whiskers with the main content more than 90%（mass fraction），white content of 87，length of 70~200 μm， and diameter of 1~3 μm were obtained.At last，some preliminary exploration on papermaking process with calcium sulfate whiskers was made.The gypsum whisker paper with white content of 85 and longitudinal and lateral tearing strength of more than 600 mN could be got in the effect of special emulsifier and binder.

Key words: phosphogypsum, calcium sulfate whiskers, purification, hydrothermal technique, papermaking