Matching Mechanism Between The Motion Energy Of Semi-autogenous Steel Balls And The Fracture Energy Of Ore In Beiya Gold Min

As the medium and fine crushing equipment in the crushing section of the beneficiation process,the processing capacity and crushing efficiency of the SAG mill directly affect the production index of the subsequent grinding and sorting process.The SAG mill mainly crushes the ore bed with large pieces of ore,supplemented by a small amount of steel balls for impact crushing of hard ores and hard-to-grind hard stone,the steel ball size of the SAG mill directly affects its processing capacity,and the precise ball load can effectively improve the impact crushing probability of hard stone particles and reduce the accumulation of hard stone.Therefore,how to determine the best ball size for SAG mills for different mechanical properties of ores is of great practical significance to improve grinding efficiency and enhance plant efficiency.This paper is based on the scientific research project of "optimization study of grinding-classification system in the second processing plant of Beiya Mining Company Limited",which addresses the problems of large accumulation of hard stone and unstable processing capacity in the second processing plant of Beiya Gold Mine.Based on the statistical principle of log-normal distribution,random specimens of irregular ores of different grain sizes are subjected to uniaxial compression tests,and the maximum breaking point of the curve is determined by the axial force-displacement curve,and the fracture energy is obtained by curve integration,and the fitting parameters of the correlation function of the Tavares crushing model are calibrated.The fracture energy of different ore grades is predicted by the power function of fracture energy and ore grade,and the optimal ball size of 140 mm is calculated by combining the fracture energy of recalcitrant ore grades with Davis steel ball motion theory.The results of the grinding comparison test in the laboratory D×L 450×450 mm mill set up with Φ120 m,Φ130 mm,Φ140 and Φ150 mm,and the closed circuit grinding effect was predicted by four open circuit grinding cycles.The Φ140 mm steel ball also ensures the crushing efficiency of large ore and the ability to eliminate hard stone and grind fine particles.The results of EDEM simulation show that the recommended Φ140 mm solution has less impact on the barrel liner in the throwing zone and can impact the ore layer more efficiently with the smallest area of kidney-shaped zone;the recommendedΦ140 mm solution can guarantee the effective impact crushing of large ore,and has the highest effective normal cumulative power to the hard stone grade and the highest cumulative power to the total normal collision of ore.The results of the Tavares crushing model show that the recommended Φ140 mm solution has the highest efficiency in crushing large ores and hard stone,and the highest yield of-25 mm fines.The reliability of combining the fracture energy with Davis ball motion theory to derive SAG ball sizes was further verified by discrete element simulation tests.