Abstract: The flow-sheet of copper-sulfide bulk flotation-copper-sulfide flotation separation and middlings returning in order in dressing plant of Yongping Copper Mine was carried out. The insufficient liberation of single mineral in middlings affects the recovery of copper. To this end, the laboratory tests and industrial tests were carried out to improve the recovery of copper in Yongping copper mine through the process of selective-classification regrinding of middlings. The lab tests indicated that compared with the original process, the new process increased copper recovery by 0.64%, and copper concentrate grade by 043%; In industrial tests, the copper recovery was increased by 0.89%, and copper grade improved by 0.38% by the new process. All these confirmed the feasibility of the new process in industrial implementation.

Key words: Selective classification regrinding of middlings, Middlings returning in order, Recovery rate of copper ore