New strategy for sustainable treatment of residual xanthate in mineral processing wastewater by using natural pyrite

Abstract

Residual xanthates in mineral processing wastewater cause severe water pollution and potential air pollution in mining areas. In this work, the subsequent degradation behavior of xanthate after adsorption on pyrite surface was investigated and confirmed for the first-time using potassium ethyl xanthate (PEX) as a model xanthate collector. The influences of different parameters, including pyrite loading, pH, temperature and oxygen, on PEX degradation were examined by monitoring the PEX concentration and the hazardous by-product CS2. The results indicated that pyrite was an effective natural material for treating residual xanthates in mineral processing wastewater. The removal rate constant increased from 0.006 h−1 to 0.2024 h−1 with increasing pyrite loading, and the CS2 generated during the PEX degradation reduced from 92.11 % to 1.95 %. Acidic pH and high temperature were conducive to PEX degradation but also resulted in more CS2 generation. Dissolved oxygen played a critical role in PEX degradation by affecting the reactive oxygen species production. The activity of pyrite declined by 23.5 % when it was reused for three runs due to oxidation products accumulation. This work provided a new strategy and practical information for using nature pyrite as an eco-friendly and cost-effective material for residual xanthate degradation in mineral processing wastewater.