The effect of PEO and organic sulfonates in enhancing phosphogypsum filtration

The effect of PEO and organic sulfonates on phosphogypsum filtration has be en evaluated using high-dolomite phosphate ore in a multistage batch minera l dissolution and filtration process. Results show that PEO and organic sul fonate compounds increase the rate of filtration. A thorough analysis of pa rameters that affect filtration was conducted to isolate the mechanism(s) b y which the additives enhance the rate of phosphogypsum filtration. The ana lysis of the data indicates that both PEO and organic sulfonate compounds d elay the measurable onset of phosphogypsum crystal nucleation. Results also suggest that the PEO alters the rate of phosphogypsum nucleation by associ ating with calcium ions and acting as an effective buffer. The reduced rate of nucleation is believed to be responsible for the observed increase in p article size and the corresponding increase in the rate of phosphogypsum fi ltration, (C) 1999 Elsevier Science B.V. All rights reserved.