Abstract: In order to improve the problem of low yield of calcium sulfate whiskers prepared by atmospheric pressure acidification. In this study,ultrasound and chloride additives (sodium chloride and calcium chloride) were used to improve the yield of whisker products. The results showed that when 8 g of phosphogypsum reacted with 400 g of acid leaching solution under the conditions of ultrasonic frequency of 40 kHz and sodium chloride concentration of 1. 5 mol / L,while calcium chloride with mass ratio (calcium chloride / phosphogypsum) of 1. 5 was added after the reaction,the whisker yield reached 77. 63%. The mechanism study shows that the sodium chloride increases the whisker yield by promoting the dissolution of phosphogypsum through charge effects and salt effects. Meanwhile,the calcium chloride improved the yield of whiskers by increasing the degree of crystallizeout through the coion effect. In addition,the whisker yield improving process produced calcium sulfate dihydrate whiskers with purity 99. 78%,whiteness 96. 43% and length-diameter 78,which met the requirements of the industry standard (DB43 / T 1155—2016). 

Key words: atmospheric pressure acidification method,phosphogypsum,calcium sulfate whisker,increasing the yield