Abstract: A mixed copper ore from abroad contains 1.45% Cu and 17.62 g/t associated Ag.The on-site flotation per formance is unsatisfactory due to the conflict between mechanical entrainment of slime and precise control of sulfidizer dosage. In this study,based on process mineralogy analysis,the reagent regime was optimized and circuit condition tests were carried out to determine suitable beneficiation parameters.The results show that using a closed-circuit process of "rough grinding,bulk flotation,rougher concentrate regrinding and cleaning",under the conditions of rough grinding fineness of 75% passing 0.074 mm,sodium silicate dosage of 600 g/t,combined collector of butyl xanthate and Z-200 at 60 + 30 g/t,and regrinding fineness of 88% passing 0.074 mm,a copper concentrate with yield of 3.89%,Cu grade of 33.19%,Cu recovery of 89.04%,and Ag grade of 337.08 g/t with Ag recovery of 74.42% in the concentrate can be obtained. In the tailings,Cu grade is reduced to 0.17% with a loss rate of 10.96%,and Ag grade is 4.69 g/t with a loss rate of 25.58%.The lost copper is mainly in the form of copper oxide (accounting for 52.94%).The experimental results provide a basis for efficient utilization of this ore resource and for plant process modification.

Key words: 　complex copper ore,associated silver,combined collector,bulk flotation,regrinding of roughing concentrate