Arsenic Removal from Mine Tailings for Recycling via Flotation

Abstract

In this study, we propose a flotation process to remove the arsenic from Samkwang mine tailings in South Korea, which contained a high arsenic content, in order to render them suitable for recycling. In order to maximize the arsenic removal from the mine tailings, three variables (type of collectors and activators, and solution pH) were systematically investigated. Characterization experiments (X-ray diffraction and electrokinetic property analyses) were carried out to complement the flotation results, and the results showed that the mine tailings were mainly composed of arsenopyrite (FeAsS), arsenic trioxide (As2O3 ,A s4O6), arsenic pentoxide (As2O5) and quartz (SiO2). The flotation results obtained using different collectors (i.e., potassium amyl xanthate (PAX), sodium oleate, sodium dodecyl sulfate) revealed that arsenic removal efficiency was greatest in the presence of PAX, which was explained by the difference in the electrokinetic properties and the interaction type of collectors with arsenic-bearing minerals. Meanwhile, the addition of activators (Na2S, CuSO4 ,N a2S+CuSO4) and the pulp pH significantly affected the arsenic removal efficiency. The arsenic removal was maximized in the presence of mixed activators (Na2S+CuSO4) at low pH. The effect of activator type and pulp pH on the arsenic removal efficiency was attributed to the coupled role of the sulphidization of arsenic oxides (e.g., AS2O3 ,A S4O6 and AS2O5), the activation of sulphidized minerals, and the formation of dixanthogen. Lastly, based on the results obtained from the parameter optimization tests (i.e., type of collector and activator, and pulp pH), a series of flotation processes consisting of rougher flotation and two subsequent scavenging flotations was designed. The results demonstrated the capability of the process to successfully remove arsenic from Samkwang mine tailings for recycling. [doi:10.2320/matertrans.M2013285]