Effect of Surfactant on Water Content of Phosphogypsum

Abstract

Phosphogypsum is a kind of solid waste produced in wet process of producing phosphoric acid, which affects the filtration rate and water content of phosphogypsum. The effects of single surfactant sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (SDBS), stearic acid (SR) and polydimethylsiloxane (PDMS) and coupled surfactants on the water content of phosphogypsum were investigated. The results show that, during the leaching process, surfactant strengthened the interfacial interactions between molecules through hydrophobic and hydrophilic orientation on solid–liquid interface, reduced the surface tension and contact angle to improve the filtration rate and reduced the soluble phosphorus loss, thereby improving the leaching rate of phosphate rock and reducing the water content of phosphogypsum. Among them, the water content of phosphogypsum was better controlled by stearic acid and sodium dodecylbenzene sulfonate than the other surface surfactants. Compared with the blank group, the stearic acid and sodium dodecylbenzene sulfonate increased the filtration rate of phosphogypsum by 24.34%, the moisture content decreased by 3%, and the phosphate leaching rate increased by 4.36%.