Determination of trace amounts of the flotation collectors ethyl xanthate and diethyl dithiophosphate in aqueous solutions by cathodic stripping voltammetry

Abstract

A cathodic stripping method has been devised for determination of low concentrations of the flotation collectors ethyl xanthate, diethyl dixanthogen and diethyl dithiophosphate. The limit of detection for ethyl xanthate was 1 × 10 −8 M by the differential pulse technique and with deposition for 2 min at −0.1 V. Three peaks were observed, each increasing in different concentration ranges of ethyl xanthate. A reaction mechanism is proposed. The detection limit for diethyl dithiophosphate was 1 × 10 −7 M by the differential pulse technique and with deposition for 3 min at −0.1 V. The analytical method was applied to determine ethyl xanthate in a sulphide mineral flotation plant and the amount of adsorbed ethyl xanthate and diethyl dithiophosphate on Cu 2S. It was found that the adsorbed ethyl xanthate forms nearly a monolayer on Cu 2S and that the amount of adsorbed diethyl dithiophosphate corresponds approximately to 0.4 monolayer.