磷石膏煅烧制备超白Ⅱ型无水石膏工艺研究OA

Phosphogypsum is a large solid waste discharged during the production of phosphate fertilizers,and its resource utilization and high-value utilization have become research hotspots in the fields of materials and environment.The use of calcined phosphogypsum can produce type Ⅱ anhydrous gypsum materials with higher whiteness and excel-lent performance,which have good application prospects.This experiment prepared uper-white type Ⅱ anhydrite(APG)by high-temperature calcination of phosphogypsum and investigated the effects of calcination temperature and additives on its properties.The results show that with the increase of calcination temperature,the standard consistency of anhydrous gypsum decreased,and the setting time is first prolonged and then shortened;The APG 28 days prepared by calcination at 900℃has the highest compressive strength of 8.23 MPa and a whiteness of 89.12%;Adding admixtures can shorten the setting time and improve compressive strength;The uper-white APG obtained by calcining at 500℃and adding 0.34%additive has excellent performance,with compressive strengths of 12.82 MPa and 45.82 MPa at 3 and 28 days,initial and final setting times of 13.0 h and 16.5 h,respectively,and a whiteness of 96.13%.The research results can provide reference for the high-value utilization of phosphogypsum.