Determination and application of the solubility product of metal xanthate in mineral flotation and heavy metal removal in wastewater treatment

The reactions of ethyl and butyl xanthates with Pb2+, C-2(+) and Zn2+ were investigated to determine the solubility products of metal xanthates using UV/Visible spectroscopic method and software WinSGW and MEDUSA. The effects of solution pH, chemical reactions and ionic strength on the determination of solubility products of metal xanthates were investigated. For a given metal, the solubility product of metal xanthate was found to decrease with the increase of the carbon chain length of the alkyl group. The determined solubility products of metal xanthates were in the order of ZnX2 > CdX2 > PbX2 and M(EX)(2) > M(BX)(2) . The accurate Ksp constant allowed more accurate calculation of the minimal concentration of xanthate ions for treating heavy metal-containing waste water to selectively separate metal ions, avoiding the potential presence of toxic xanthates in the treated water.