针对易门铜业Φ2.4×3.6 m球磨机装补球制度不合理、磨矿产品细度低、分级机效率偏低及循环负荷偏高等问题，基于矿石的力学性质及粒度组成分布情况，采用段氏球径半理论公式对推荐初装介质配比进行计算，最终确定初装球方案为Φ80 mm∶Φ60 mm∶Φ50 mm∶Φ40 mm=30%∶25%∶25%∶20%。将推荐钢球配比方案与现场方案进行实验室磨矿对比试验，结果表明：与现场方案相比，推荐方案的过粗级别+0.150 mm产率降低了2.38个百分点，磨矿细度（-0.074 mm占比）提高了5.14个百分点，中间级别-0.150+0.010 mm产率提高了1.08个百分点，磨矿技术效率增长了3.39个百分点。由此可见，采用推荐初装钢球配比作为易门铜业Φ2.4×3.6 m球磨机磨矿介质，其优化效果明显。

With the rapid development of China’s society economy，the demand for copper mineral resources in various fields of our country is increasing day by day，and more and more “poor，fine and miscellaneous” copper resources are being mined，which makes the aim of the grinding operation changes to as much as possible to reduce the yield of over-fine grades and over-coarse grades in grinding products，and increase the yield of intermediate grades of grinding products.At present，there are some problems in the grinding operation of Yimen Copper Co.，Ltd.，such as unreasonable ball filling system of Φ2.4×3.6 m ball mill，low fineness of grinding products，low efficiency of classifier and high circulating load.In view of the above problems，based on the mechanical properties such as ore density，uniaxial compressive strength，elastic modulus and Poisson’s ratio，and the particle size distribution of grinding cycle products such as belt feeding，classifier overflow，classifier sand return and ball mill discharge，the calculation formulas for the ball diameter of various ball mill steel balls that are widely used at home and abroad was compared and analyzed.The semi-theoretical formula of Duan’s ball diameter was adopted to calculate the recommended initial loading medium ratio.Finally，the initial loading plan is determined as：Φ80 mm∶Φ60 mm∶Φ50 mm∶Φ40 mm=30%∶25%∶25%∶20%.And four groups of schemes was set up，namely field scheme，recommended scheme，oversized scheme，and undersized scheme， to carry out laboratory grinding comparison test.The grade yield，grinding fineness and grinding technical efficiency were used as evaluation indicators to study the optimization of the size and ratio of steel balls in the mill.After optimization，compared with the on-site scheme，the yield of +0.150 mm over-coarse grades of the recommended scheme is reduced by 2.38 percentage points，the grinding fineness of -0.074 mm is increased by 5.14 percentage points，and the yield of the intermediate grade （-0.150+0.010 mm） is increased by 1.08 percen-tage points.The efficiency of grinding technology increased by 3.39 percentage points.It shows that using the recommended ratio of initially charged steel balls as the grinding medium of Yimen Copper’s Φ2.4×3.6 m ball mill has obvious optimization effect.On the premise of improving the grinding fineness，the intermediate grade yield is increased，and the over-coarse grade is reduced.The production rate can effectively improve the effi-ciency of grinding technology，and achieve the improvement of grinding technical indicators of the dressing plant，which is of great significance to improving the efficiency and reducing consumption of the dressing plant.