Butyl xanthate removal from mineral processing wastewater via electrochemical treatment using copper electrodes

Abstract

Residual flotation collectors are the most widespread organic pollutants in tailings wastewater and their efficient abatement usually involves energy-consuming and high cost treatments. In this study, the applicability of electrocoagulation for removing butyl xanthate (BX), a typical thiol collector for sulfide ore flotation, from wastewater were investigated. Chemical oxygen demand (COD) and turbidity variation were monitored to reveal the removal behavior of BX. The results showed efficiency of copper based electrocoagulation was significantly higher than that of conventional aluminum or iron electrodes. More than 91.5% of COD was removed within 6 min electrolysis operated at 6 mA/cm2, natural pH and 0.02 M Na2SO4 concentration. Calcite and copper electrocoagulation played a synergistic role in accelerating COD removal of the wastewater. Mechanism analysis indicated that the electrocoagulation process involves two successive stages. First stage: the transformation of BX into insoluble copper–organic complexes; second stage: destabilization of the complex colloid by charge neutralization mechanism. Calcite particles adsorbed a portion of the suspended complexes and acted as coarse particles that facilitated the settling of fine particles. The proposed simple electrocoagulation process could represent an effective strategy for removing BX and mitigating environmental pollutants discharged from the mineral processing industry.