Grinding Properties Of Nano-Ceramic Ball In Vertical Stirred Mills

The development of mineral resources at home and abroad is moving towards “low-grade,fine-grained dissemination and complex”.These mineral resources require fine grinding or ultrafine grinding to achieve valuable mineral liberation.Vertical mill is gradually replaced ball mill as fine grinding equipment.Steel ball is commonly used as grinding medium for fine grinding.Nanoceramic ball is a new grinding medium with high energy efficiency.In this paper,nano-ceramic ball and steel ball are used as grinding medium and magnetite,quartz,and binary mixed minerals are used as grinding materials.The particle size distribution and energy consumption characteristics of ground products are discussed in the mono-binary mineral system.Actual iron ore was used for verification.This paper comes to the following conclusions:With the same grinding fineness,the specific energy of magnetite,quartz,binary mixed minerals and actual iron ore first decreases and then increases as the diameter of nano-ceramic ball decreases,and the specific energy of 15 mm nano-ceramic ball is the lowest.At the same specific energy,with the decrease of the diameter of the nano-ceramic ball,the qualified particle size content of magnetite,quartz,binary mixed minerals and the actual iron ore ground products first increases and then decreases.The qualified particle size content of 15 mm is the largest.Therefore,the grinding ability of 15 mm nano-ceramic ball is the best.At the same specific energy,compared with same mass of steel ball,the content of newly qualified particle size content of magnetite,quartz,binary mixed minerals and actual iron ore ground products of nano-ceramic ball are more than that of steel ball,so the grinding ability of nano-ceramic ball is stronger than that of steel ball in the same mass.At the same grinding fineness,the specific energy of nano-ceramic ball is lower than that of steel ball.Binary mixed minerals are affected by the hardness of component mineral.The energy split factor of magnetite is greater than 1,while that of quartz is less than 1.The specific breakage rate of magnetite(small hardness)is larger,and that of quartz(large hardness)is smaller.The grinding process of binary mixed minerals is non-uniform grinding,and the component minerals with low hardness have priority broken.The quartz(high hardness)can accelerate magnetite(small hardness)to broken.Therefore,there is selective grinding in the grinding process of hard and soft minerals.The grinding performance of nano-ceramic ball is better than that of steel ball with the same mass.Nano-ceramic ball is a new type of energy saving grinding medium in vertical mill,which has a better application prospect.