Comparative analysis of colloid-mechanical microenvironments on the efficient purification of phosphogypsum

The storage of phosphogypsum could bring huge burden to the environment, while the traditional method of washing and purifying phosphogypsum produced a large amount of waste water and colossal energy consumption. The novel colloidal-mechanical method as a new treatment technology of purifying phosphogypsum was benefit for the large-scale comprehensive utilization of phosphogypsum, but its purification effect and influencing factors needed to be further studied. Surfactants like Span-80, TX-100 and Tween-80 were one of major factors for colloidal-mechanical purification method about whiteness improvement and impurities removal of phosphogypsum. It created colloidal-mechanical microenvironments during the purification process of phosphogypsum, and helped to realize the best removal effects and purification technology of phosphogypsum. After characterization, it showed that the whiteness of phosphogypsum increased under the action of micelle and mechanical force, and the removal effects of soluble phosphorus and fluorine impurities were noticeable. The whiteness value of purified PAS could reach 51.9, which was 57.8% higher than natural PG. The phosphorus content in the slurry solution of PAS was 274.649 ppm, which was 208% higher than PG. The fluorine content in PAS was 0.289 wt%, which was 24.3% lower than PG. The purification effect of phosphogypsum was the best through the micro-environment created by Span-80 and mechanical force. This study provided a green design direction for the critical purification and its further utilization of phosphogypsum. This work provided a clear idea for solving the current purification dilemma of phosphogypsum with an outstanding application prospect.