Research On Finishing Grinding Of Vertical Roller Mill And Flotation Technology Of Low-Grade Magnesite Ore

Material crushing is an inefficient process consuming high energy and high steel.Therefore,how to reduce the wear of grinding media,improve the energy utilization of grinding process,improve the size distribution characteristics of grinding products has become the main content of the research process of grinding material.Vertical roller mill is a new type of grinding equipment,it is widely used in cement,coal,chemical,electric power industry in recent years.Not only can effectively grinding materials,but also has a small footprint,low power consumption,small steel abrasion,low noise,high degree of automation,and its benefits are attracting more and more people's attention and adoption.In this paper,the vertical roller mill and ball mill grinding was tested with magnesite flotation conditions in Dandong area of Liaoning Province.Respectively,the open circuit and closed circuit test was carried on.On the basis of process mineralogy,studies to determine the principle of the separation process of magnesite and gangue minerals.Under the condition of the same ores,after the procedure of the closed circuit,Vertical roller mill-flotation test can get 47.24 percent MgO,0.27 percent SiO2,0.29 percent CaO and 65.14 percent of the magnesite can be recovered.The ball mill-flotation test can get 47.07 percent MgO,0.25 percent SiO2,0.57 percent CaO and 61.95 percent of the magnesite can be recovered.The recovery of MgO in the vertical roller mill flotation concentrate is about 3 percentage points higher than that of the ball mill.And CaO in vertical roller mill-flotation concentrate grade was 0.29%,conform to the industrial of superfine magnesite standard.Through an analysis of ore properties in both grinding methods.It is concluded that vertical roller mill for flotation in the middle of the graded product content is 2.39%higher than that of ball mill.The concentration of iron ions in both flotation pulp grinding methods were determined.Vertical roller mill-flotation pulp iron ion concentration are lower than those of ball mill,and the flotation concentrate quality is better than the ball mill.Through an analysis of vertical roller mill grinding mechanism,we conclude that the vertical roller mill grinding the ore is crushed mainly biased manner,cutting and grinding,Through the analysis of the North Heavy Industries Group MPS32 vertical roller mill related parameters.It is concluded that the grinding material is in the range of the vertical roller mill.This paper through the magnesite vertical roller grinding-flotation tests and ball mill wet grinding-flotation tests and related theories,providing some experimental and theoretical foundation in applied and theoretical study of the vertical roller mill.