| For ilmenite resources in China,the grade is generally low and is difficult to exploit.As a dry separation technology and compared with wet separation,triboelectric separation has the advantages of low energy consumption,no need of dehydration and little environmental pollution.Conduct the research of triboelectric separation of ilmenite has great significance to the development of ilmenite resources in China,especially in the areas of water shortage.In this paper,in order to lay the foundation for the triboelectric separation of ilmenite,firstly,the triboelectric characteristics of ilmenite and the main gangue minerals were analyzed,numerical simulation method was used to optimize the design of the laboratory triboelectric separator and the separation experiments of the simulated mixed materials and the actual ilmenite samples was carried out.The main conclusions of this paper are as follows:(1)The ilmenite ore was detected by using X ray diffraction method and the main gangue minerals were obertiite,albite,manganneptunite,quartz,kaersutite and ilmenite.Triboelectric characteristics of ilmenite and three kinds of gangue minerals of feldspar,quartz and mica tribocharged with PVC,PPR,PMMA,Teflon,Coppor,stainless steel,quartz glass were studied by using a laboratory charge-mass ratio measurement system,and the results show that when particles tribocharged with PVC,copper and stainless steel,objective mineral opposite charged with gangue minerals.And among the three tribocharger materials,PVC makes the maximum differences between ilmenite and gangue minerals,charge-mass ratio of ilmenite is 3.34 nC/g,feldspar,quartz and mica are-2.14,-4.05 and-2.93 nC/g,respectively.When PVC was selected as the tribocharger material,the influence of particle size and friction length on the triboelectric characteristics were studied.Results indicated that the optimum size fraction of the four minerals was-0.25 +0.074 mm and charge of particles increase with the increase of tribocharging length and there is a significant logarithmic relation.(2)In this paper,numerical simulation method was used to optimize the design of laboratory triboelectric separator.The trajectory of particle group,changes of pressure distribution of gas and particle movement with movement distance in body under different angles between the tribocharger wall and vertical direction were simulated.The simulation results show that when the angle is 22 degrees,the particles can collide with the tribocharger wall 25 ~ 30 times and the impact strength is larger and the charge effect is the best.At the same time,the gas pressure difference in the separator is small and will not interfere with the particle separation process.(3)According to the simulation optimization parameters,PVC was selected as the tribocharger material,and aluminum plate was used as the electrode plate for the laboratory triboelectric separator.Separation experiments of simulation mineral composed of ilmenite concentrate and gangue minerals with mass ratio of 1:3:5:1 were conducted using the laboratory separator and the influences of separation voltage,feed rate and gas flow rate on the separation results were studied.The experimental results show that when the other factors remain unchanged,the separation efficiencies of the simulated material increase first and then decrease with the increase of the factors explored.When the separation voltage is 20 kV,the feed quantity is 4.7 g/s and the air volume is 80 m3/h,the concentrate product with ilmenite content of 24.61%,recovery of 89.96% can be got and the separation efficiencies reach the best.In the process of separation,it is more effective for the separation of the ilmenite and mica,and the separation behavior of feldspar and quartz is weak.Based on the separation results of simulated materials,the separation experiments of ilmenite at grade of 15.47% were carried out,and the concentrate product with 28.40% grade and 14.03% yield was obtained after three separation processes and based on this a process flow was put forward. |
PDF Full Text Request