Research on the Process Mineralogy of Phosphogypsum Using Mineral Liberation Analysis System

For the first time, process mineralogy including the chemical composition, mineral composition, main mineral particle morphology and embedded features, mineral dissociation analysis, and the occurrence status of harmful elements of an industrial phosphogypsum from Hubei provence was conducted using the mineral liberation analysis (MLA). The results provides a theoretical basis for the purification of phosphogypsum and impurity removal. It shows that the industrial phosphogypsum is mainly consist of oxygen, calcium, sulfur, and silicon. To improve the whiteness of the phosphogypsum, the coloring impurities elementsincluding iron, titaniumneed to be removed. The mineral composition of this phosphogypsum is relatively simple, and the content of gypsum mineral meets the standard of first-level phosphogypsum (≥85%) in GB/T 23456-2009 "Phosphogypsum", followed by a small amount of quartz, potassium feldspar, chlorite, iron-containing aluminosilicate, limonite and pyrite, etc. The impurity phosphorus in the phosphogypsum is mainly distributed in apatite and phosphorus pentoxide, and deep dephosphorization process requires water washing combined with pickling.