Study on Improvement of Phosphorus Release Characteristics of a Phosphate Rock Powder by Wet Grinding

Planetary ball mill was used for ultra-fine grinding of phosphate rock powder with P₂O₅ content of 27.07%. The influences of pulp concentration and grinding time on particle size and solubility of powder products were investigated under the determined optimum dry grinding process parameters. By means of X-ray diffraction analysis, scanning electron microscope analysis and contact Angle measuring instrument, the variation law of crystallization degree, microstructure and surface free energy of pulverized products under different grinding time were investigated. The results showed that under the condition of 55% pulp concentration and 150 min grinding time, the median diameter and solubility of powder products were 1.74 μm and 66.24%, respectively. With the extension of grinding time, the crystallization degree of phosphate ore in the phosphate ore powder decreases significantly, there is basically no large particle in the powder product, the product contact angle gradually decreases, the corresponding surface free energy shows an increasing trend, and the phosphorus release characteristics of the phosphate ore powder are improved.