Optimization Study of Cobalt Enrichment from Iron Tailings by Flotation Using Response Surface Methodology (RSM)

Cobalt (Co) is an important strategic metal that has a wide variety of applications. In minerals, Co often occurs with pyrite (FeS2) in the form of isomorphism and is typically enriched by flotation. In this study, iron tailings containing cobaltiferous pyrite (Co-py) from the Handan–Xingtai region in China were used to enrich Co by flotation. Single-factor flotation tests were conducted to investigate the appropriate ranges of four operational factors: sodium butyl xanthate (SBX) concentration, turpentine oil (TO) dosage, pulp concentration, and pulp pH. The response surface methodology based on the Box–Behnken design was performed to determine the effects and interactions of various operational factors on the enrichment ratio and Co recovery. Two mathematical models were developed and accurately predicted the responses. The optimum solution of the models showed that an enrichment ratio of 2.30 and a Co recovery of 97.35% could be achieved with an SBX concentration of 350 g/t, TO dosage of 0.43 g, pulp concentration of 8%, and pulp pH of 3.51. Validation experiments under these conditions further validated the reliability of the model predictions. This work provides a solid experimental foundation for operational parameter design and process optimization in Co enrichment from iron tailings.