Abstract: A copper-containing slag from electric furnace impoverishment in Yunnan is recycled into the raw material by adding CaO for roasting in oxygen atmosphere. The influences of holding time, holding temperature, slag grain size, and gas phase atmosphere on magnetic roasting are investigated. SEM and XRD are used to analyze the microstructure and phase change of roasted slag. The influences of copper slag roasted by adding CaO and grain size are observed by TGA. The results show that the addition of CaO is effective in promoting the decomposition of Fe2SiO4. And the finer the grinding is, the better the reaction is. With increasing of roasting temperature and holding time, a-Fe2O3 is increased, Fe3O4 is first increased, and then decreased at 850℃. Excessively high temperature and long time are not conducive to the accumulation of Fe3O4, and a low oxygen potential is not conducive to the gas-solid reaction of Fe3O4 concentration. The optimal conditions of Fe3O4 concentration are air atmosphere, 850℃ and 2 h roasting.

Key words: oxidation, roasting, concentration, CaO, Fe3O4, copper slag

摘要： 以云南某铜冶炼厂电炉贫化渣为原料，在有氧气氛下加入CaO高温焙烧铜渣，分析了焙烧时间、焙烧温度、铜渣粒度、气相气氛对磁化焙烧效果的影响，利用SEM和XRD等对焙烧样品的微观形貌、物相变化进行分析，并通过热重分析考察了添加CaO及研磨粒度对铜渣焙烧过程的影响. 结果表明，加入CaO能有效促进Fe2SiO4分解，磨矿越细越有利于反应进行，随焙烧温度提高、焙烧时间延长，a-Fe2O3增多，而Fe3O4先增加、温度超过850℃后减少；过高温度及过长焙烧时间不利于Fe3O4富集，且过低的氧势不利于富集Fe3O4的气固反应进行，Fe3O4富集的优化条件为空气气氛下850℃焙烧2 h.

关键词: 氧化, 焙烧, 富集, CaO, Fe3O4, 铜渣