Abstract: Under the influences of fine and complicated dissemination,high rate of copper oxidation of the ore,the production indexes in a large copper mine in Jiangxi constantly keeps falling. In order to solve the problems existing in on-site process,beneficiation tests were carried out by the process of partially preferential copper flotation Cu-S bulk flotation at coarser grinding fineness,separation of copper and sulphur for regrinding of Cu-S bulk flotation products. The experiment result indicated that with the one-stage grinding fineness of 68% -0.074 mm,copper concentrate with copper grade of 22.79% and copper recovery rate of 86.04%,and sulphur concentrate with sulphur grade of 43.86% and sulphur recovery rate of 58.73% were gained respectively by adopting the closed-circuit process of fast preferential copper flotation by one roughing and one cleaning,sulphur-copper bulk flotation by one roughing and one scavenging,separation of copper and sulphur by one roughing,one cleaning and one scavenging after regrinding mixed concentrates of the middling of preferential copper flotation and the primary concentrate of the bulk flotation to 98.07% -0.074 mm,and middles back to the regrinding. Compared with the production indexes,the copper grade of the copper concentrate was increased by 1.46 percentage points,and the copper recovery rate was increased by 3.60 percentage points,so the indexes were improved significantly.

Key words: Fast partially preferential copper flotation, Copper-sulphur bulk flotation, Regrinding of middlings, Collector PLQ-4