2002 Volume 42 Issue 2 Pages 132-138
The leaching behavior of F-containing hot metal dephosphorization slags (HM-slag) in seawater has been found different from that in distilled water. F-containing slags demonstrate higher dissolution degree in seawater, and the F content is lower in the case of seawater due to the precipitation of F-containing Mg(OH)2 which favorably occurs at solid/seawater interface where pH is higher than 10. This F-bearing Mg(OH)2 is not a stable form of F-containing mineral in seawater. It follows from the present study that, of the F-containing minerals in the HM-slags observed, only CaF2 and Ca5(PO4)3F are stable in marine environments. The F solubility of CaF2 is independent of pH, while that of Ca5(PO4)3F increases with increasing pH. The F content in seawater saturated with CaF2 and Ca5(PO4)3F is all below 10 ppm regardless of pH.
