Flotation preconcentration of cobalt and nickel by lead(II) hexamethylenedithiocarbamate

A flotation method for simultaneous separation of cobalt and nickel traces from fresh water is proposed. Lead(II) hexamethylenedithiocarbamate, Pb(HMD TC)(2), was used as a new collector for the precipitate flotation preconcen tration. It was obtained during the reaction between hexamethyleneammonium- hexamethylenedithiocarbamate. HMA-HMDTC, and lead(II) ions. Mass of lead, m (Pb), amount of hexamethylenedithiocarbamate, n(HMDTC-), pH of the system, induction time, type of surfactants, which are all important parameters for the successful flotation, were studied and optimized. After flotation prec oncentration. electrothermal atomic absorption spectrometry (ETAAS) was app lied for cobalt and nickel determination. The results obtained by ETAAS wer e compared with the results obtained by inductively coupled plasma-atomic e mission spectrometry (ICP-AES). The detection limit of the proposed method is 0.025 mug/L for cobalt and 0.0157 mug/L for nickel.