Efficient recovery of phosphorus from phosphogypsum leachate based on struvite precipitation
Phosphogypsum leachate is a liquid produced during phosphogypsum stacking.It has the characteristics of high phosphorus content,low pH,high corrosivity,and high concentrations of heavy metals.If it seeps into the ground over time,it will seriously pollute the groundwater and sur-face water and pose a significant threat to the surrounding basin environment and human health.In this study,a struvite precipitation method was proposed to recover phosphorus sources from phospho-gypsum and its leachate to prepare valuable percolate-based struvite crystal(PSL-S).The core idea is to improve the recovery rate of valuable components by converting the raw mineral phase of phos-phorus in the leachate,which enables the production of struvite using industrial solid waste instead of pure reagents,thereby solving two issues:the high price of struvite prepared by pure reagents and the substantial waste of valuable components in phosphogypsum leachate.The study involved three varia-bles:Mg/P molar ratio,N/P molar ratio,and pH.Two indicators,namely,the phosphorus recovery rate in leachate and the purity of struvite from PSL-S,were selected.Through a combination of single-factor influence experiments and optimization orthogonal experiments,combined with phase analysis,the optimal conditions for the preparation of PSL-S were obtained,specifically,when the N/P molar ratio was 5∶1,the Mg/P molar ratio was 1.6∶1,and the pH value was 9.5,with a phosphate recov-ery rate of 87.73%and a PSL-S preparation purity of 78.24%.The successful preparation of PSL-S enables the efficient resource utilization of phosphogypsum leachate,greatly reduces the production cost of struvite,and provides technical support for the resource utilization of phosphorus chemical waste.
Struvite precipitation methodPhosphogypsum leachateStruviteOptimized orthogonal experimentResource utilization of solid waste
国家科技期刊平台
NSTL
万方数据
