Study on the influence of graphite and sphalerite flotation separation by carboxymethyl cellulose

It was previously understood that the smelting process involving high-graphite content sulfide concentrates would result in a chemical reaction with oxygen, which would subsequently release a significant amount of CO 2 . This not only contributes to environmental pollution but also hampers smelting efficiency and quality, consequently escalating smelting costs. Therefore, this work improved the purity of sulfide ores by flotation methods using environmentally friendly depressant to depress graphite. The results of the micro-flotation study reveal that the flotation separation of graphite and sphalerite mixed ore was best under the flotation reagent concentration system of 10 mg/L PBX, 10 mg/L CMC and 8 × 10 −5  mol/L CuSO 4 , and the flotation recoveries were 8.22 % and 79.24 %, respectively. Analyses conducted using FTIR and XPS reveals that PBX competed with CMC for the adsorption of Cu 2+ , and exhibited a stronger adsorption for Cu 2+ on the sphalerite surface compared to CMC, which increased the adsorption of PBX with the sphalerite surface. Meanwhile, the graphite is only affected by CMC, which results led to sphalerite surface hydrophobicity and graphite surface hydrophilicity for efficient separation. Further confirmation was provided by DFT and MD simulations that Cu 2+ were adsorbed on the graphite (001) surface through physical interactions. The adsorption order was as follows: CuOH + < Cu 2+ < Cu(OH) 2 . CMC chemisorbed with Cu 2+ on the graphite surface, resulting in an increase in the adsorbed content of CMC on the graphite surface and an improvement in the hydrophilicity of graphite. These results indicate that CMC effectively depress graphite during the flotation separation of graphite and sphalerite.