Thermodynamical Study on the Reaction between Mercury and Xanthate

To investigate the mechanism of the reaction between mineral surface and xanthate in flotation, the reactions between mercury and xauthate were thermodynamically studied with measuring the potential of the following cells: Hg|Hg2X2|X-||Hg2++||Hg.(The abbreviation ‘X’ is used for xanthate.)The standard potential, the free energy, the solubility product, and the reaction heat of the mercury xanthate were determined. Xanthates used in the experiments were ethyl xanthate, iso-propyl xanthate, and amyl xanthate.The results obtained are as follows:-(1) The standard potentials of the cells, Hg|Hg2X2|X-||Hg2++|Hg, are 1.066 volt for ethyl xanthate, 1.078 volt for iso-propyl xanthate, and 1.109 volt for amyl xanthate.(2) The change of free energies for formation of mercury xanthate are -4.91×104cal for ethyl xanthate, -4.97×104cal for iso-propyl xanthate, and -5.11×104cal for amyl xanthate.(3) The solubility products of mercury xanthate are 1×10-36for ethyl xanthate, 4×10-37for iso-propyl xanthate, and 4×10-38for amyl xanthate.(4) The reaction heats of the formation of mercury xanthate are -5.46×104cal for ethyl xanthate, -5.53×104cal for iso-propyl xanthate, and -5.68×104cal for amyl xanthate.(5) The stable formation of metal was xanthate was considered on mercury surface contacting a dilute aqueous sloution of xanthate by comparing the potential of the cell, Hg|Hg2X2|X-||Hg2++|Hg, with that of the cell, Hg|X-||Hg2++|Hg.