Abstract

Efficient separation of Cu–Mo sulfide minerals from moraine materials remains a major challenge for low-grade, high-moraine Cu–Mo ores. Fine-grained muscovite induces severe slime coating and gangue entrainment, thereby markedly reducing flotation selectivity. In this work, a biodegradable polymer depressant, polyaspartic acid (PASP), was employed to regulate Cu–Mo sulfide flotation under muscovite interference conditions. Microflotation tests, particle size distribution analysis, zeta potential measurements, SEM-EDS observations, contact angle measurements, and XPS analyses were conducted to clarify the dispersion behavior, slime-coating mechanism, and selective adsorption characteristics of PASP. The results demonstrated that PASP selectively depressed muscovite at relatively low dosages while exerting negligible influence on the floatability of chalcopyrite and molybdenite. Notably, at a dosage of 15 mg/L, PASP reduced muscovite recovery by 43.07% and 31.23% more effectively than sodium silicate and sodium hexametaphosphate, respectively, demonstrating superior selective depression efficiency under moraine interference conditions. Particle size distribution and zeta potential analyses confirmed that PASP effectively weakened heterocoagulation and electrostatic attraction between muscovite and sulfide minerals, thereby suppressing slime coating and improving slurry dispersion stability. SEM-EDS and contact angle analyses further revealed that PASP significantly reduced muscovite deposition on sulfide mineral surfaces while maintaining the hydrophobicity of chalcopyrite and molybdenite. High-resolution XPS analysis further indicated that PASP adsorbed onto muscovite mainly through coordination between carboxylate groups and surface Al–OH sites, forming a stable hydrophilic adsorption layer. Overall, PASP provides a low-dosage, highly selective, and biodegradable depressant strategy for mitigating muscovite-induced slime coating and improving the flotation separation of Cu–Mo sulfide ores under moraine interference conditions.

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