Method for recovering fluorapatite from a leachate of phosphogypsum by ionic activity control

Abstract

The application belongs to the technical field of phosphogypsum resource utilization, and particularly relates to a method for recovering fluorapatite from phosphogypsum leaching solution by ion activity control. The method comprises the following steps: on-line detection of fluorapatite saturation index of phosphogypsum leaching solution original solution, real-time adjustment of Ca source / P source / F source supplementing amount to keep the system supersaturated; addition of background electrolyte, complexing agent and crystal face control agent in the above-processed solution to obtain a crystallization precursor solution; control of temperature to 50-90 DEG C, adjustment of system pH to 6.4-6.9, supplementing of Ca 2+ and addition of FA crystal seeds to stir and mix uniformly; increase of temperature to 70-95 DEG C and increase of pH to 6.8-7.8, addition of surface rearrangement promoter for directional crystallization, solid-liquid separation, washing and drying of the solid product to obtain fluorapatite. The application controls and regulates FA crystal nucleation through ion activity control, thereby significantly improving the yield and purity of the target product.

Images