Study on transfer laws of phosphorus and fluorine impurities during producing calcium sulfide through sulfur reduction decomposition of phosphogypsum
The reduction and decomposition to produce sulfuric acid and low-carbon calcium-based materials is a powerful way to realize the large-scale disposal and circular utilization of phosphogypsum.Clarifying the migration and transformation rules of phosphorus and fluorine,two key impurities in the decomposition process of phosphogypsum,plays an important role in regulating the reaction of sulfur reduction and decomposition of phosphogypsum.This article firstly provided a com-prehensive analysis of the properties and composition of phosphogypsum,identifying the forms in which impurities such as phosphorus and fluorine exist within it.By using thermodynamic software to simulate calculations,the phase transformations of these two impurities before and after the reaction were revealed.Utilizing pure gypsum,the key factors affecting the de-composition of phosphogypsum to produce calcium sulfide were explored.Under optimized conditions,the migration and changes of different amounts of phosphorus and fluorine impurities during the decomposition process were investigated.The research results showed that when the temperature was 800℃,the reaction time was 2 h,and the molar fraction of sulfur was 40%,the decomposition rate of phosphogypsum could reach more than 98%.Under this condition,phosphorus impuri-ties mainly existed in the solid phase products in the form of insoluble phosphorus,and some eutectic phosphorus would be released and existed in the form of insoluble phosphorus.The fluorine mainly existed in the form of insoluble fluorine,and a small part entered the gas phase products.The research results of this paper could provide certain theoretical guidance for the recycling economy utilization of phosphogypsum.
sulphurcalcium sulfatecalcium sulfidephosphogypsumimpuritiestransfer law
NETL
NSTL
万方数据
