The global amount of waste electrical and electronic equipment (WEEE) is growing fast. Non-ferrous metals represent a large portion of this waste, and they can be potentially recovered via black copper smelting. Alumina and magnesia, originating from the e-waste or fluxes, can be present in the feed of a secondary copper smelter in varying concentrations. Our study focuses on the impact of MgO on the slag chemistry of high-alumina iron silicate slags. The distributions of tin and nickel as minor elements were also investigated and compared with literature data. The equilibrium study was performed at 1300 °C in reducing conditions. Three different slag mixtures with 0, 3, and 6 wt% MgO were used in the study. The MgO addition significantly reduced the solubility of alumina in the slag and changed the primary spinel phase composition. The combined effects of increasing MgO and decreasing Al₂O₃ concentration in the slag regarding the distribution of tin were noticeable, i.e., its deportment to metal phase increased, but for nickel the effect was negligible. Theoretical calculations were performed for estimating the isolated effect of MgO on the distributions and they confirmed the beneficial effect on the behavior of tin but showed no impact for nickel.

Graphical Abstract

中文翻译：

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氧化铝和镁质黑渣冶炼黑铜中镍和锡的熔渣化学性质和行为

全球废弃电子电气设备（WEEE）的数量正在快速增长。有色金属占这种废物的很大一部分，可以通过黑铜冶炼加以回收。来自电子废物或助熔剂的氧化铝和氧化镁可以以不同的浓度存在于二级铜冶炼厂的进料中。我们的研究重点是MgO对高铝硅酸铁渣的化学性质的影响。还研究了锡和镍作为次要元素的分布，并与文献数据进行了比较。在还原条件下于1300°C进行平衡研究。在研究中使用了三种含0、3和6 wt％MgO的炉渣混合物。MgO的添加显着降低了氧化铝在炉渣中的溶解度，并改变了尖晶石相的组成。关于锡的分布，炉渣中₂ O _3的浓度是显着的，即，其向金属相的比例增加，但是对于镍，影响可忽略不计。进行了理论计算以估计MgO对分布的孤立作用，他们证实了对锡行为的有益作用，但对镍没有影响。

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