Abstract: Acid-insolubles often lead to serious erosion to equipment in the production of nitrophosphate.Besides,they frequently deposits in the equipment and pipelines and causes blockage.Presently,the acid-insolubles in nitrophosphate are generally separated by mechanical methods,by which,however,the removal percentage is remarkably low and only reaches about 20%.Therefore,flocculation method was adopted in the separation of acid-insolubles.Four flocculants with good deformation efficiencies were selected from 15 flocculants by optimization experiments.Experimental results showed that the optimal dosage for these four flocculants was 50 g/m³,and the removal percentage of the acid-insolubles reached more than 90%.The method can simplify the process,save the cost and will open up a new way for separation of acid-insolubles in the production of nitrophosphate.

Key words: acid-insolubles, flocculants, flocculated separation