The invention relates to a method for preparing modified
phosphogypsum through
calcination without water scrubbing. The method is as follows: firstly, composite excitant and modifier are added into
phosphogypsum and uniformly mixed, wherein, the weight percent of the
phosphogypsum is between 85 and 95 percent; the weight percent of the composite excitant is between 2 and 5 percent; the weight percent of the modifier is between 3 and 10 percent; the composite excitant is green
vitriol and
aluminum sulphate, and the modifier is
calcium oxide and
cement; secondly, after uniform mixing, the mixture is dried at a
drying temperature of between 100 and 110 DEG C, and the
moisture of the phosphogypsum is lower than 8 percent; thirdly, the mixture enters into a calciner, is calcined for 0.5 to 1 hour at a temperature of between 150 and 300 DEG C, and is naturally cooled to prepare the modified phosphogypsum. The method decomposes and volatilizes harmful substances such as
phosphor,
fluorine, organic substances and so on contained in the phosphogypsum or converts the harmful substances into
inert substance
calcium pyrophosphate which is harmless to products, thereby not only avoiding secondary
pollution but also reducing or avoiding influence of harmful chemical microconstituents contained in the phosphogypsum on the quality and the performance of the products. Moreover, the method shortens the
processing time by 15 to 20 percent, saves the investment by 3 to 8 percent and reduces the
energy consumption by 10 to 20 percent.