Modified phosphogypsum as well as preparation method and use of modified phosphogypsum

The invention belongs to the field of waste residue utilization and specifically relates to a modified phosphogypsum as well as a preparation method and a use of the modified phosphogypsum, solving the technical problem that a novel modified phosphogypsum is provided, which is prepared by taking phosphogypsum, papermaking white clay and kiln dust as raw materials so that industrial waste residues are utilized thoroughly to overcome the defect that the previous modifiers need other natural minerals and chemical raw materials to further achieve the purpose that wastes are treated by using wastes. The modified phosphogypsum is prepared from the following raw materials in parts by weight based on dry matters: 0.2-0.9 part of phosphogypsum, 0.9-8.1 parts of papermaking white clay, and kiln dust accounting for 0.5%-3% of the total weight of the modified phosphogypsum. The preparation method of the modified phosphogypsum comprises the treatment steps of washing, flotation, alkaline neutralization modification and the like; meanwhile, the modification process is basically performed in slurry, and therefore, the phosphogypsum is modified thoroughly, and stable and reliable in quality. The obtained modified phosphogypsum can be used as a cement retarder.