关键词: 金矿石, 毒砂, 重选, 中矿再磨, 浮选

Abstract: The Au grade of a gold ore in Hunan is 2.41 g/t，the main gold-bearing minerals are arse⁃ nopyrite and pyrite，the main gangue minerals are kaolin，chlorite and so on. The disseminated grain size of gold minerals is very fine，and the amount of single gold particles is very small. Most gold particles are connected with arsenopyrite or contained in arsenopyrite，and a small part of gold particles are contained in pyrite. The beneficiation tests were carried out to determine the suitable separation technology of the ore. The results showed that gravity separation by shaking was applied for the samples when the grinding fine⁃ ness is -0.074 mm accounting for 78%. Then，the middlings from gravity separation was processed by the closed-circuit flotation process of one roughing and two cleaning and middlings return in sequence when the grinding fineness is -0.074 mm accounting for 87.77%. Finally，the gold concentrate with yield of 1.84%，Au grade of 111.45 g/t and recovery rate of 85.05% was obtained. The quality of gold concentrate met the quality requirements of first grade products containing arsenopyrite，and the gold recovery was well realized.

Key words: gold ore, arsenopyrite, gravity separation, regrinding of midllings, flotation