Mineralogy and Flotation Purification of Calcium Fluoride Sludge

The fluorine-containing sludge produced by the photovoltaic industry contains a large amount of calcium fluoride minerals, but the current utilization is extremely difficult. Objective To fully utilize the fluorite resources in fluorine-containing sludge, Method a typical photovoltaic sludge was investigated as the research object, with adetailed process mineralogy being systematically carried out. The occurrence state and micromorphological characteristics of the sludge particles were clearly clarified. ResultThe sludge particles had poor crystallinity, fine particle size, and serious agglomeration, hindering their separation and enrichment. Based on the physical and chemical properties, a strategy of acidic wash and depolymerization-flotation purification for calcium fluoride sludge was proposed and carried out. The grades of two sludges increased from 49.00% and 48.51% to 76.93% and 75.67%, respectively, while the recoveries were 84.79% and 80.88%, respectively. ConclusionFurther investigation revealed the micromorphological difference and separation mechanism of the flotation concentrate and tailings, thereby providing a scientific basis for the flotation recovery and resource utilization of calcium fluoride sludge.