铅渣煤基直接还原—磁选选铁试验

Experiments on Iron Concentration from Lead Slag with Coal-based Direct Reduction and Magnetic Separation

云南澜沧某铅渣Fe、Cu、Pb、Zn含量均较高,采用煤基直接还原—磁选工艺对其中的铁进行了回收工艺技术条件研究,并对试验过程中的重要产物进行了XRD和SEM-EDS分析。结果表明,含铁25.98%的铅渣在还原煤用量为铅渣质量的30%、焙烧温度为1 200℃、焙烧时间为40 min、直接还原产物磨矿细度为-74μm占83.92%、1粗1精弱磁选磁场强度分别为180、56 kA/m情况下,可获得铁品位为93.68%、回收率为77.59%的金属铁粉;煤基直接还原可使铅渣中粒度细微、嵌布关系复杂、磁性弱的含铁矿物转变成粒度粗大、与渣界限分明、磁性强的金属铁,为弱磁选分离创造了有利条件。

There are high content of Fe, Cu, Pb, Zn among Lancang lead slag in Yunnan. Tests on technical condi- tions of iron concentration with the process of coal-based direct reduction and magnetic separation are made, and the key minerals in tests are analyzed by XRD and SEM-EDS. The results show that under the conditions of the coal consumption occupying 30% of lead slag, roasting temperature at 1 200 ℃ for 40 min, with particle size of -74 txm 83.92%, iron powder with Fe grade of 93.68% and recovery rate of 77.59% were obtained by the process of one roughing-one cleaning with low intensity magnetic fields at 180 kA/m and 56 kA/m separately. The coal-based direct reduction method can trans- fer Fe-contained minerals with fine particle size, complex dissemination and low intensity magnetic field into metal Fe with large particle size, well district between iron and slag and high intensity magnetic field, which creates a favorable condition for low intensity magnetic separation.