Influence of pH, Pb2+, and temperature on the electrochemical dissolution of galena: environmental implications

We investigated the influence of pH, Pb2+, and temperature on the electrochemical dissolution of galena. The experimental results showed the following: (1) Acidic or alkaline conditions stimulate galena electrochemical dissolution. The galena electrode corrosion current density (j (corr)) increased from 0.072 to 0.143 mu A center dot cm(-2) as the pH decreased from 6.0 to 2.0 (promotion efficiency of 98.61 %) and from 0.066 to 0.132 mu A center dot cm(-2) as the pH increased from 8.0 to 12.0 (promotion efficiency of 100 %). (2) Pb(NO3)(2) promotes galena electrochemical dissolution at low concentrations (< 0.10 mol center dot L-1) and inhibits it at high concentrations (> 0.10 mol center dot L-1) because Pb2+ has two different functions during galena electrochemical dissolution. (3) Higher temperatures are favorable for galena electrochemical dissolution. The galena j (corr) increased from 0.143 to 0.226 mu A center dot cm(-2) as the temperature increased from 25 to 55 A degrees C. These experimental results are of direct significance for the control of environmental pollution during galena weathering and mining activities.