Abstract: In a low-grade complex copper mine，the copper content in the copper middlings ob ⁃ tained during production is relatively high.However，due to the complex mineral composition and fine dis ⁃ semination size，effectively recover of the copper resources was hard to obtain by conventional beneficia ⁃ tion processes.To address this issue，a new technology for diversified treatment of middlings was adopted to improve the existing process.The results showed that using the original process and original reagents，a copper concentrate with recovery rate of 91.27%and concentrate grade of 22.06%could be obtained.In contrast，with the new process and new reagents，a copper concentrate with recovery rate of 92.87%and concentrate grade of 24.90%could be achieved.Compared with the original process and original reagents， the copper grade of the concentrate increased by 2.84 percentage points，and the recovery rate increased by 1.60 percentage points when using the new process and new reagents.

Key words: low-grade, embedded particle size, middlings, process, recovery rate