基于二次回归正交设计及均匀设计的柞水菱铁尾矿最佳回收工艺参数

在条件试验基础上, 分别采用二次回归正交设计及均匀设计对柞水菱铁尾矿进行了深度还原-磁选试验研究, 研究了配碳量、碳酸钠用量、还原温度、保温时间、磨矿时间和磁场强度对铁精矿品位的影响, 以磁选铁精矿品位为响应值, 利用逐步回归法建立了二次多项式模型。二次回归正交设计试验结果表明, 在配碳量21.12%、碳酸钠含量11.55%、焙烧温度1 280 ℃、保温时间130 min、磨矿时间55 s、磁场强度238 mT时, 可获得品位为90.13%、回收率为81.77%的最终选别指标；均匀设计试验结果显示, 在配碳量21.43%、碳酸钠含量14.79%、焙烧温度1 277 ℃、保温时间127 min、磨矿时间51 s、磁场强度260 mT时, 可获得品位88.75%、回收率83.62%的最终选别指标。由2种试验方法所建立模型而获得的最佳工艺参数可靠, 具有实际应用价值。

Optimum Parameters for Recovering Iron from Siderite Tailings in Zhashui with Quadratic Regression-Orthogonal Design and Uniform Design

Based on condition tests, an experimental study was carried out for recovering iron from siderite tailings in Zhashui by adopting deep reduction-magnetic separation process respectively with quadratic regression orthogonal composite design (QROCD) and uniform design, in which effects of factors, including coal and Na₂CO₃ dosages, reduction temperature and holding time, grinding time and magnetic field strength, on iron concentrate grade were explored and a quadratic polynomial model was established by stepwise regression method with the grade of iron concentrate from magnetic separation as a response value. The QROCD experiment showed that with coal dosage at 21.12%, Na₂CO₃ dosage at 11.55%, reduction temperature at 1 280 ℃ and reduction time of 130 min, grinding time of 55 s, magnetic field strength at 238 mT, a concentrate approaching 90.13% Fe grade at 81.77% recovery was obtained. While the uniform design experiment with coal dosage at 21.43%, Na₂CO₃ dosage at 14.79%, reduction temperature at 1 277 ℃ and reduction time of 127 min, grinding time of 51 s, magnetic field strength at 260 mT, resulted in 83.62% recovery into a concentrate grading 88.75% Fe. It is concluded that the optimal parameters obtained from the above two models were reliable and practical.