Method for controlling of calcium sulfate crystal form in wet process phosphoric acid process by controlling content of impurities

The invention provides a method for controlling a calcium sulfate crystal form in a wet process phosphoric acid process by controlling the content of impurities. The method comprises the steps: mixingphosphoric acid, sulfuric acid and water to obtain an acid regurgitation solution, and mixing and stirring the acid regurgitation solution, calcium dihydrogen phosphate monohydrate and impurities toform a material 1; mixing water and sulfuric acid to form a material 2; adding the material 1 and the material 2 into a reactor to react at 50-90 DEG C for 2-5 h, then, pumping the obtained product byusing a peristaltic pump, wherein the pumping rate is same as the sum of the adding rates of two solutions. The control on the calcium sulfate crystal form is realized by investigating influences single impurity such as Si/Al/Fe/Mg/K/Na and the cooperation of multiple impurities to a calcium sulfate crystallization process and determining the control range of the impurities, so that the activityof phosphogypsum serving as