The optimization of lead electrodeposition from leachant of lead laden cupels

Abstract

Disposal of lead laden cupels is proving problematic to mining and metallurgical companies due to environmental and health issues. In this study the optimization of operation parameters for the electrode position of lead metal from acetic acid leachant was carried out. The effects of voltage, temperature, concentration, size of electrode and the effect of the space between the electrodes were investigated. Acetic acid (10%) was used as a leachant in the optimization process. The optimum voltage was found to be 6 V, with the best operating temperature of 20°C. The amount of lead deposited increased with increase in concentration of the lead in solution up to an optimum concentration of 2271.1 ppm. However the extraction efficiencies tended to decrease with increase in concentration. The optimum inter-electrode distance was observed to be 4 cm with 0.5 cm radius electrodes that gave the largest extraction efficiency (70.9%). Acetic acid (10%) was preferred as a leachant compared to EDTA (0.1 M) because it gave higher leaching and electrode position efficiencies (73.3% vs 68.1) and (95% vs 90.8) respectively. EDTA (0.1 M) was however found to be less corrosive to the carbon electrodes as observed with acetic acid. Other advantages of acetic acid are that it is cheaper, can be obtained from renewable sources and is easy to use because there is no need for constant pH monitoring and adjustments.