摘要
为研究磁铁矿石多级破碎的演化特征,基于岩石破碎分形理论,构建了磁铁矿石多级破碎的物理试验模型,采用落锤冲击试验机开展不规则磁铁矿石多级破碎试验,模拟磁铁矿石从初始粒度破碎至目标粒度的一般过程,实现了矿石机械破碎过程的室内试验反演,揭示了碎块粒度与分布特征逐级演化规律。结果表明:粒度级配曲线、平均粒径、中值粒径和粒度分形维数可完整描述磁铁矿石多级破碎演化特征;随着破碎级数的增加,磁铁矿石的粒度级配趋于均匀分布,级配变化程度逐渐减小;碎块平均粒径与中值粒径降低,但降低幅度逐渐减小,平均粒径的变化梯度更为显著;磁铁矿石每级破碎结束的碎块粒度分布具有分形特征,多级破碎过程具有自相似性,每级破碎结束后碎块粒度分形维数增大,但增大速率逐渐减小,最终趋于稳定值。研究结果提出了一种通过落锤冲击多级破碎模拟矿石机械破碎演化过程的方法,首次从物理试验的角度验证了矿石机械破碎过程符合破碎分形理论,为磁铁矿石破碎粒度控制与工艺改进提供了理论依据。
To research evolution characteristics of magnetite multistage crushing,a physical experimental model was established based on the fractal theory of rock fragmentation.Multistage crushing tests on irregular magnetite were carried out by drop weight impact apparatus to simulate the general process of magnetite crushing from initial size to target size.Therefore,the indoor test inversion of the mechanical crushing process of ore was realized,and the gradual evolution regulations of fragment size and distribution characteristics were revealed.The results show that the particle size distribution curve,average particle size,median particle size and fractal dimension can completely describe the evolution characteristics of magnetite multistage crushing.With the increase of crushing steps,the particle size distribution of magnetite tends to be uniform,the degree of gradation change gradually decreases,the average particle size and median particle size of the fragments decrease as well,whose decreasing range gradually decreases,and the change gradient of average particle size is more significant.The particle size distribution of magnetite after each crushing stage has fractal characteristics.The multistage crushing process has self-similarity.After each crushing stage,the fractal dimension of fragment size increases to be a stable value with the gradually decreasing at its increasing rate.A method was proposed to simulate the evolution process of ore mechanical crushing by means of multistage crushing with drop weight impact.It is the first time to verify that the mechanical crushing process of ore accords with the fractal theory of ore crushing from the aspects of physical tests.The research provides a theoretical basis for particle size control and process improvement of magnetite crushing.
作者
高锋
甘德清
甘泽
邵静静
GAO Feng;GAN Deqing;GAN Ze;SHAO Jingjing(Deparment of Mining Engineering,Shanxi Institute of Technology,Yangquan.Shanxi 045000,China;College of Mining Engineering,North China University of Science and Technology,Tangshan,Hebei 063000,China)
出处
《矿业研究与开发》
CAS
北大核心
2021年第11期149-154,共6页
Mining Research and Development
基金
国家自然科学基金项目(52074124)
河北省自然科学基金青年基金项目(E2020209254)
山西工程技术学院科研启动项目(2021QD-10)。
关键词
磁铁矿石
分形理论
多级破碎
破碎特征
演化规律
Magnetite
Fractal theory
Multistage crushing
Crushing characteristics
Evolution regulation
