An innovative method for simultaneous stabilization/solidification of PO43− and F− from phosphogypsum using phosphorus ore flotation tailings.

Phosphogypsum (PG) contains plenty of PO 4 3− and F− and some heavy metals. Phosphorus ore flotation tailing (POFT) mainly consists of dolomite (CaMg(CO 3) 2) and calcium fluophosphate (Ca 5 (PO 4) 3 F). Traditional methods of POFT and PG storage could seriously damage the ecological environment. In this study, an innovative method for simultaneous stabilization/solidification (S/S) of PG and POFT was studied. The effects of PG and POFT mass ratio, S/S pH, solid-liquid ratio and temperature on the concentrations of PO 4 3− and F− in the leaching solution as well as the characteristics of POFT and PG were studied. Meanwhile, the simultaneous S/S mechanisms of PG and POFT and leaching test were investigated. The results showed that the concentrations of F− and PO 4 3− in the leaching solution were 6.0 mg/L and 4.0 mg/L, respectively, when the mass ratio of PG and POFT was 1:1 and the initial pH was 8.0 after being solidified for 30 days. F− and PO 4 3− were mainly stabilized as (Ca, Mg, Zn)F 2 and (Ca, Mg, Zn) 3 (PO 4) 2 , respectively. Leaching test results showed that PO 4 3− was reduced from 508.0 mg/L to 4.0 mg/L, and the concentrations of all the measured heavy metals and F− were within the permitted level for the GB8978-1996 after 30 days S/S. Image 1 • Simultaneous S/S of PG and POFT is an economically feasible method. • F− and PO 4 3− were mainly stabilized in the form of chemical precipitates in PGP. • Heavy metals concentrations were within the permitted level after 30 days S/S. [ABSTRACT FROM AUTHOR]