Abstract: In order to recover and utilize calcium source in phosphogypsum, feed grade calcium hydrogenphosphate was prepared by the reaction of phosphoric acid with calcium hydrosulfide prepared from phospho-gypsum. The results show that the route of preparing calcium hydrogen phosphate from phosphogypsum is fea-sible; both wet process phosphoric acid and thermal process phosphoric acid can produce feed grade calciumhydrogen phosphate products in line with national standards; compared with the two, wet process phosphoricacid has advantages in cost, while thermal process phosphoric acid has advantages in quality. The experimen-tal results have a certain guiding significance for the comprehensive utilization of phosphogypsum.

Key words:  phosphogypsum, calcium hydrosulfide, calcium hydrophosphate