Application of pre-magnetic separation to address grinding classification density effects and enhance iron-copper separation in deep polymetallic magnetite ores

• Utilized BPMA for detailed characterization of polymetallic magnetite. • Process mineralogy identified the intergrowth of associated sulfide minerals, optimizing separation processes. • Integrated pre-magnetic separation into grinding and classification to address density effects. • Enhanced liberation and separation of valuable components, ensuring effective flotation enrichment. This study investigates the challenges faced in the grinding and classification process of a polymetallic magnetite ore from Anhui, particularly focusing on low classification efficiency, significant over-grinding, and decreased metal recovery rates. By analyzing the mineralogical properties of the ore, specifically mineral composition, intergrowth relationships, intergrowth particle size, and liberation degree, with an emphasis on magnetite, chalcopyrite, cobalt minerals, and precious metal minerals, this research aims to identify the underlying causes of these issues. Subsequent single-factor experiments were conducted to assess the effects of magnetic field strength and grinding parameters on the enrichment of magnetite and chalcopyrite. Under optimal processing conditions, with a magnetizing current of 0.25 A and a grinding fineness of 65% passing through a 200-mesh sieve, the application of butyl xanthate as a collector during mixed rough flotation achieved a copper recovery rate of 89.54%. Building on these findings, the study further discusses the impact of various process flow optimizations on grinding, classification operations, and the recovery of target minerals. Additionally, it evaluates the advantages and disadvantages of different processing methods in practical applications and ultimately proposes a suitable mineral processing flow for intermediate to deep ore deposits.