Enhanced electrochemical removal of arsenic and heavy metals from mine tailings

Electrochemical remediation process can be used to separate arsenic and heavy metals from mine tailings and prevent them from leaching into the environment. Citric acid, EDTA, NaOH, HCl and H2O were used as chemical extractants in the electrokinetic process. The electrochemical extraction with citric acid as extractant was the most effective method to remove arsenic, iron and manganese from mine tailings highly contaminated. As, Fe and Mn removal from mine tailings was influenced for the citric acid concentration, the liquid/solid ratio, the current intensity and the extraction time. Different values for each of these parameters were tested in order to check their effects on the removal efficiency. The highest efficiency and smallest residual concentrations of contaminants were reached for concentrations of citric acid of 0.8 mol/L, liquid/solid ratio of 10, current intensity of 800 mA and extraction time of 6 h. Too high current intensities or too long extraction times caused corrosion problems in the steel parts of the system. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.