Study on phosphogypsum as a cement retarder

For phosphogypsum employed as a cement retarder instead of natural gypsum, the such 2 problems as soluble P component and high moisture therein must be solved to avoid the excessive retardation, as well as the difficult feeding and pipe blocking. 2 ways of making phosphogypsum into solidified body in size of 50 mm×50 mm are presented and some comparison are made in physical characteristic of cement prepared, the results show that solidified phosphogypsum is similar with natural gypsum in cement solidifying time; 2.0 MPa strength yields after 6 days in nursing and 24 hours in soaking, which is desirable for the stability of feeding and calculating.