司家营铁矿高梯度强磁选机磁介质改进试验

Experiment on Improve of Magnetic Medium in High Gradient High Intensity Magnetic Separator of Sijiaying

为改善司家营铁矿选厂高梯度强磁选作业对微细粒铁矿的回收效果,以现场高梯度强磁选给矿为研究对象进行了高梯度磁选机磁介质改进试验。单一磁介质试验表明,应用菱形磁介质时精矿铁品位随背景磁感应强度提高的降低幅度较应用棒介质时小,铁回收率提高幅度也较应用棒介质时小;在低背景磁感应强度时,采用菱形介质获得的精矿铁回收率较采用棒介质时高,在高背景磁感应强度时,采用棒介质获得的精矿铁回收率较采用菱形介质时高。在此基础上进行了菱形介质与Φ2.0mm棒介质按1∶1混合磁介质与单一磁介质对比试验,结果显示:不同背景磁感应强度下采用混合磁介质时选别指标均优于采用单一磁介质;背景磁感应强度为600 m T时,应用混合磁介质时获得的精矿铁品位较应用现场原介质提高了1.53个百分点,铁回收率提高了2.32个百分点,-0.045 mm粒级铁回收率提高了3.40个百分点。ANSYS有限元分析结果表明:混合磁介质兼具了菱形聚磁介质磁感应强度高与大直径棒介质作用深度大的优点,磁场梯度高,分布均匀,而且混合磁介质中的棒介质在捕捉磁性矿物的同时,还起到了改变进入分选区域的矿浆流向的作用,使矿浆流向菱形介质周围,使微细粒磁性矿物颗粒更易被菱形介质棒的上下尖端捕捉,合理利用了磁场空间,提高了对微细粒铁矿物的分选效率。

In order to improve recovery effect of micro-fine iron ore in high gradient high intensity magnetic separation of Sijiaying iron dressing plant, high gradient high intensity magnetic separation magnetic medium treating experiments were car- ried out with on-site high gradient high intensity magnetic separation feeding. Single magnetic medium experiment results showed that, compared with rod medium,when using rhombic magnetic medium, decrease range of iron concentrate grade with increase of background magnetic induction intensity is lower, and increase range of iron recovery is lower too. In the condition of low background magnetic induction intensity ,recovery of iron ore concentrate is higher when rhombic magnetic medium was used compared with rod medium, while in the condition of high background magnetic induction intensity, recovery of iron ore concentrate is higher when rod medium was used compared with rhombic magnetic medium. Based on this, comparison experiments was carried out with the rhombie magnetic medium and φ2.0 mm rod medium mixed with number ratio of 1 ： 1 as me- dium, and results showed that, separation effects of mixed magnetic medium is better than that of single magnetic medium under different background magnetic induction intensity; when background magnetic induction intensity is 600 mT, compared with using rod magnetic medium on-site ,when mixed magnetic medium was used,iron concentrate grade increased by 1.53 percentage points,iron recovery increased by 2. 32 percentage points, and recovery of -0. 045 mm fraction increased by 3, 40 percentage points. ANSYS finite analysis results showed that mixed magnetic medium has advantages of both high magnetic induction intensity of rhombic magnetic medium and big action depth of and large diameter rod medium, thus it has characteristics of high magnetic field gradient and homogeneous distribution, and while rod medium collecting magnetic minerals in mixed magnetic medium, it also play a role of changing flow direction of pulp in separation area simultaneously, consequently, the pulp will flow around rhombic magnetic medium, which make micro-fine magnetic ore easier to be collected for upper and lower tips of rhombic magnetic medium, therefore magnetic field was rationally used, and increased separation efficiency of micro-fine iron ore.