Production process of calcium dihydrogen phosphate

The present invention is a method of producing monocalcium phosphate, which is characterized by the decomposition of rock phosphate with an excess of phosphoric acid, to give after separation of slag containing a plurality of metal impurities and rare earth metal and phosphoric acid solution containing monocalcium phosphate, partially after the monocalcium phosphate is crystallized from the phosphoric acid solution, it separated to obtain calcium dihydrogen phosphate, calcium dihydrogen phosphate with sulfuric acid decomposition is still contained in the mother liquor, obtained after isolated white gypsum phosphate, phosphate rock decomposition for batch . The present invention makes use of elemental calcium in the phosphate rock, sulfuric saving, to give a white gypsum byproduct slag and metal impurities for use.