矿石破碎颗粒黏结模型黏结键特征及表征

The characteristics and representation of bond key in bonded particle model for ore crushing

目的针对矿石颗粒黏结模型与实际矿石破碎特性存在差异造成的仿真不准确问题,重点对不同粒级矿石颗粒黏结模型中的黏结键特征进行研究。方法依据矿石强度尺寸效应理论,设计铜矿石颗粒黏结模型中基础颗粒间的黏结键参数,应用离散元方法对30,40,60 mm三种粒级铜矿石矿样进行落重试验和破碎仿真。本文给出黏结键等效临界变形的概念,讨论了矿石落重试验t10和冲击能量的关系,探讨黏结键参数变化规律。结果结果表明,三种粒级铜矿石颗粒黏结模型破碎仿真与落重试验粒级质量分数的平均误差分别为1.75%,1.66%,1.84%,试验和仿真得到的破碎粒度质量分数具有很好的一致性;法向和切向等效临界变形可以表征黏结键强度,单位冲击能量下落重试验的tn10可以表征矿石强度。结论利用黏结键等效临界变形和tn10的对应关系确定黏结键参数,提高了矿石颗粒黏结模型的建模效率和仿真精度。

Objectives Aimed at addressing the inaccuracy of simulation owing to the difference between the ore bonded particle model and the actual ore crushing feature,the characteristics of bond key in the bonded particle model of different size were emphasized.Methods According to the theory of ore strength size effect,the bond parameters between basic particles in the bonded particle model of copper ore were designed.As for three sizes of copper ore samples including 60 mm,40 mm and 30 mm,the drop weight test and crushing simulation by discrete element method were carried out.The concept of equivalent critical deforma⁃tion of bond was given.The relationship between t10 from drop weight test and impact energy was discussed.The variation rule of bond parameters was explored.Results The results show that the average errors of mass percentage from crushing simulation and drop weight test of three kinds of size copper ore are 1.75%,1.66%and 1.84%,respectively.The crushing mass percentage obtained by test and simulation are in good agreement.The bond strength can be characterized by normal and shear equivalent critical deformation.The tn10 of unit impact energy from drop weight test can characterize the ore strength.Conclusions The bond pa⁃rameters are determined by the corresponding relationship between the equivalent critical deformation of the bond and the tn10,which improves the modeling efficiency and simulation accuracy of the ore bonded particle model.