Selective depression of pyrite with lignosulfonate-based biopolymers in the flotation of copper sulfide minerals

摘要

Pyrite, a gangue mineral, is commonly associated with valuable sulfide minerals, such as chalcopyrite, chalcocite, galena and sphalerite. The separation of pyrite from these valuable sulfide minerals by flotation is difficult due to the activation of pyrite by lead and copper ions added intentionally or dissolved from minerals. In this study, a type of biopolymers, modified from lignosulfonates, was used to depress pyrite in chalcopyrite flotation based on previous investigations. It was found that these biopolymers selectively depressed pyrite flotation with little effect on chalcopyrite flotation. The observed selectivity resulted from the selective adsorption of biopolymers on pyrite as revealed by ToF-SIMS measurements. The adsorption isotherms also showed that biopolymers exhibited higher affinity towards copper-activated pyrite than chalcopyrite.