The Research On Selective Liberation Of Vanadium-titanium Magnetite

China has rich reserves in vanadium titanomagnetite resources.As a kind of associated mineral with many valuable metal components,its comprehensive utilization is of great value.However,because of its complex mineral association and uneven distribution of useful minerals,it is difficult to realize efficient liberation and lead to difficult separation and low comprehensive utilization rate,which is a "hard bone" of iron ore dressing.Therefore,the development of new efficient liberation technology is the prerequisite for the comprehensive utilization of its multi valuable components.In this paper,Panzhihua vanadium titanomagnetite is taken as the research object.Based on the research of mineral technology,the differences of physicochemical properties among the components in the ore are analyzed,then use microwave and liquid nitrogen pretreatment to treat it.The influence factors and mechanism of pretreatment on the selective liberation of vanadium titanomagnetite were studied.The main conclusions are as follows.1.Microwave heating power and time are the main factors that affect the ore treatment.Under the conditions of feeding particle size of-2mm ～ + 0.15 mm and adding amount of 150 g,microwave power of 2500 W and treatment time of 30 s have the greatest improvement on grinding efficiency,which is the optimal microwave treatment condition.After microwave pretreatment,the maximum yield of-0.074 mm size fraction of ore grinding product can be increased by 6.27 percentage points;the overall monomer liberation degree of grinding product can be increased by 3.84 percentage points;the iron grade can be increased by 2.62 percentage points;and the iron recovery can be increased by 5.52 percentage points.2.Liquid nitrogen pretreatment can effectively improve the grinding efficiency and monomer liberation degree of ore.the water content of ore and freezing time are the main factors affecting the freezing effect of liquid nitrogen.Under the conditions of feeding particle size of-2mm ～ + 0.15 mm and adding amount of 150 g,the most suitable liquid nitrogen pretreatment conditions are soaking time of 0.5h,freezing in liquid nitrogen for 10 min and boiling water bath for 30 min.After liquid nitrogen pretreatment,the maximum yield of-0.074 mm size fraction of ore grinding product can be increased by 6.18 percentage points;the overall monomer liberation degree of grinding product can be increased by 2.90 percentage points;the iron grade can be increased by 3.16 percentage points after magnetic separation;and the iron recovery can be increased by 3.78 percentage points.3.The mechanism of microwave heat treatment is to make use of the difference of microwave absorbing property and thermal expansion property between different components to produce thermal stress during microwave heating,so as to produce cracks at the junction of different phases;while the mechanism of liquid nitrogen freezing treatment is due to the difference of thermal expansion property between different components and the volume expansion of water in the ore when it is cold,resulting in a strong tensile stress during liquid nitrogen freezing,which will lead to internal cracks and promote the selective liberation of ore.After experimental study,microwave heating pretreatment is more conducive to efficient and selective liberation of ore.