The invention discloses a method for producing industrial diammonium
hydrogen phosphate from crude
phosphoric acid, and belongs to the technical field of production of industrial diammonium
hydrogen phosphate. The method solves the problem that the industrial-grade diammonium
hydrogen phosphate product cannot be directly prepared by using crude
phosphoric acid and
ammonia gas as main raw materials. The method comprises the following steps: S1, mixing crude
phosphoric acid and
ammonia gas, and neutralizing for the first time, wherein the
neutralization degree of the first time is 1.50-1.60; s2, filtering the material liquid obtained after the first time of
neutralization; s3, concentrating the filtered material liquid, adding
ammonia gas into the concentrated material liquid, and neutralizing for the second time with the
neutralization degree of 1.95-2.0; and S4, cooling and crystallizing the material liquid obtained after the secondary neutralization to obtain an industrial-grade diammonium
hydrogen phosphate product. The industrial-grade diammonium
hydrogen phosphate product is produced by adopting a two-step
neutralization method, so that the purpose of ammoniation
impurity removal is achieved, heat release of ammoniation neutralization reaction is facilitated, the use of steam is reduced, the existing process is shortened, and the cost is reduced.