Technology for producing medium element fertilizer by using phosphogypsum

The invention relates to the technical field of a medium element fertilizer, and especially relates to a technology for producing the medium element fertilizer by using phosphogypsum. The technology comprises the following steps: performing phosphogypsum pretreatment, mixing phosphogypsum and a soil conditioner, performing fragmentation and granulation on a mixture to obtain the granular-fertilizer, and performing steps of primary drying, primary cooling, secondary drying, and secondary cooling to obtain a product. The free water proportion in the pre-treated phosphogypsum is 12-15%, the granular-fertilizer is heated to 75-85 DEG C while primary drying, the proportion of the free water in the granular-fertilizer is reduced to 10-13%, the temperature of the granular-fertilizer after primarycooling is reduced to 65 DEG C, the granular-fertilizer after secondary drying is heated to the temperature of 75-80 DEG C, and the proportion of the free water in the granular-fertilizer is reducedto lower than 8%, A granul