Phosphate Rock Dissolution Using Nitric Acid

摘要

This work describes the effect of process parameters on the acidulation of Moroccan phosphate rock using nitric acid, i.e., the nitro-phosphate process. A series of bench scale experiments were conducted, using a stirred tank reactor (STR) system, to investigate the chemical reactions involved and optimum conditions for the formation of nitro-phosphate fertilizer. The effect of reaction time, temperature, mixing speed, acidulation ratio, and acid concentration were investigated, and were found to have an effect on the dissolution of P-2O_5 from the phosphate rock, using nitric acid. An increase in nitric acid concentration resulted in an increase in P_2O_5 dissolution, however, the dissolution was also found to be a function of acidulation ratio. A nitric acid phosphate rock ratio of 4:1 ensured 90% dissolution for nitric acid concentration >30%.