METHOD FOR PREPARING FEED GRADE CALCIUM HYDROPHOSPHATE FROM WASTE LIQUID COMPRISING PHOSPHORIC ACID

摘要

A method for preparing feed grade calcium hydrophosphate from a waste liquid comprising phosphoric acid, comprising the following steps: heating the waste liquid comprising phosphoric acid under stirring, and adding a CaCO₃ slurry to a pH value of 2.5-3.5 to obtain a first mixed system and keeping same at the temperature for a period of time; adding a Ca(OH)₂ slurry to the first mixed system to a pH value of 5.0-6.5, and subjecting a second mixed system to crystal growth; performing filtration and reserving the residues, and the residues being the feed grade calcium hydrophosphate. In the method for preparing feed grade calcium hydrophosphate from the waste liquid comprising phosphoric acid, a CaCO₃ slurry is used to perform first stage treatment on the waste liquid comprising phosphoric acid, the final pH value of the first stage treatment being 2.5-3.5, and then a Ca(OH)₂ slurry is added to perform second stage treatment, the final pH value of the second stage treatment being 5.0-6.5, finally, crystal growth is performed, followed by filtration to obtain the feed grade calcium hydrophosphate. The method for preparing the feed grade calcium hydrophosphate from the waste liquid comprising phosphoric acid can maximize the recycling of the phosphoric acid resources in the waste liquid comprising phosphoric acid.