贫赤铁矿高压辊磨机产品强磁预选试验研究

HighIntensity Magnetic Pre-concentration of Hematite Ore Comminuted by High-pressure Grinding Roller

对贫赤铁矿石的高压辊磨机产品分别进行干式预选试验和湿式预选试验的基础上进行了分级预选研究。试验结果表明:干式预选过程中,降低带速能够降低预选尾矿品位和产率,提高预选精矿收率。湿式预选过程中,减小介质棒间隙,增加介质棒直径和提高背景磁场强度均能够降低预选尾矿品位和产率,提高预选精矿回收率。贫赤铁矿石单一形式的预选效果均不理想。对贫赤铁矿石高压辊磨机产品进行预先分级,筛上粗粒级产品进行干式辊式预选,筛下细粒级产品进行湿式高梯度预选,当分级粒度为0.5mm时,预选效果最佳。在入选铁品位24%的条件下,高压辊磨机粉碎产品的综合预选精矿品位较原矿品位提高8.44个百分点,回收率达86.51%,抛尾产率达35.71%。

High intensity pre-concentration of hematite ore comminuted by high-pressure ganndmg roller（HPGR）was studied by dry magnetic separation and wet magnetic separation, and then the classifying pre-concentration test was done. The results showed that as the roll speed was reduced,the tailings grade and the tailings yield were reduced, while the Fe recovery were raised in dry pre-concentration. As the rod gap was decreased,the rod diameter and the BMFI were increased, the tailings grade and the tailings yield were reduced, while the Fe recovery was raised in wet pre-concentration. The pre-concentration performances were not satisfactory by the single separating method. But when the products in HPGR were screened firstly, and then the oversize products were separated by the dry magnetic separator and the undersize products were separated by the wet high-gradient magnetic separator, the optimum per- formance for the classifying pre-concentration was obtained at the classifying size of 0. 5ram. After classifying pre- concentration, the overall concentrate grade was improved by 8.44% with a recovery of 86.51% and a tailing yield of 35.71% under the condition of the beneficiation feed grade as 24%.