Gold has been widely used because of its easy forging and corrosion resistance，and it promotes the development of daily life，industry and global economy. Gold ore separation is mainly composed of raw ore crushing，grinding classification，flotation and concentration. The quality of grinding products is directly determined by the addition system of grinding medium，which affects the beneficiation index and the economic benefit of the concentrator. Grinding operation is an important part of gold recovery. The optimization of grinding medium system can effectively improve the quality of grinding products，and make more qualified fractions enter the flotation process，which is beneficial to the separation and enrichment of gold mines. There are some problems in the first-stage grinding workshop of Jiaojia gold mine，such as high unit ball consumption of ball mill，low grinding efficiency and unreasonable particle size composition of grinding products，which greatly affect the normal production situation and separation index of concentrator and lead to low economic benefits of mine. In order to solve the above problems，this paper optimized the grinding medium addition system of ball mill to improve the quality of grinding products. The mechanical properties of ore were determined and the particle size composition of ore was screened. Based on the mechanical properties of ore and the particle size distribution of grinding cycle products，the medium ratio of the recommended scheme was calculated by Duan's semi-theoretical formula of spherical diameter as Φ90∶Φ70∶Φ50∶Φ40∶Φ30=15∶25∶20∶15∶25. In addition，four groups of schemes，i.e.，field scheme，recommended scheme，oversize scheme and undersize scheme，were tested in laboratory grinding contrast test and grinding contrast test under different sand return ratio in a discontinuous Φ450×450 mm ball mill in laboratory. The yield of roughing grade，easy-to-select grade，optional grade and superfine grade were taken as evaluation indexes. Finally，the initial ball loading scheme was determined as follows：Φ90∶Φ70∶Φ50∶Φ40∶Φ30=15∶25∶20∶15∶25.The industrial test of 3# mill （MQG2736） in Jiaojia gold mine was started on October 26，2016. After the industrial test，the content of -0.074 mm in ore discharge of No.3 mill increased by 4.06%，the content of +0.30 mm decreased by 5.64%，and the processing capacity of No.3 mill increased by 6.42% during the industrial test period. This shows that the recommended ball ratio scheme is more suitable for increasing the content of middle easy-to-choose fraction and reducing the content of over-crushed fraction than before the industrial test，which can effectively increase the output per hour，and has certain reference significance for similar mines.

http://www.goldsci.ac.cn/article/2022/1005-2518/1005-2518-2022-30-1-122.shtml