Optimization and evaluation of the effect of impurities on phosphoric acid process performance using design of experiments

In the present work, we aim to investigate the impact of impurities co-existing in phosphate rock on reactive crystallization and filtration stages during the phosphoric acid dihydrate process. The primary influent impurities were identified by simulating the industrial optimal conditions on a laboratory scale and employing a design of experiments strategy; the positive and negative simultaneous effects for each impurity were elucidated and quantified. In addition, 4 mathematical models describing and predicting their effect on filterability, aspect ratio, thickness, and mean diameter of crystals were established. The obtained results conclude that CO2, F−, Al2O3, and SiO2 impose highly significant contributions and are the most influential species governing the process.