Abstract: Copper slag dilution is an important method for the sustainable development of copper metallurgy industry. As high-quality copper concentrates continue to be consumed, low-grade, high-impurity copper concentrates are gradually being utilized. As a typical low-quality copper concentrate, the content of Al2O3 in the copper slag after smelting of high-alumina copper concentrate has increased. With the change in copper slag composition, controlling the slag characteristics is critical to recover copper in the copper slag dilution process and to reduce copper losses in slag. In this work, ISASMELT copper slag was used as raw material. Analytical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM-EDS), and infrared spectroscopy (FTIR) are used to elucidate the effects of different Al2O3 contents on the phase and structure of copper slag during the copper slag dilution, as well as the effect of phase transformation and structure change on copper loss in slag. The effects of different CaO additions on the phase transformation, structure and copper loss of high-alumina copper slag are also investigated. The results show that with the increase of Al2O3 content, high melting point hercynite can be formed in the slag, and the polymerization of slag increases and the aluminosilicate structure becomes more complex. This increases the slag viscosity and the copper loss of slag. The addition of CaO in the high alumina copper slag would form high melting point hedenbergite, monticellite, and the viscosity increases. However, with the increase of CaO addition, the slag structure tends to simplify and viscosity decreases. At the CaO addition of 2wt%, the slag contains the lowest copper content of 0.78wt%. The addition of small amount of CaO can reduce the copper loss of high-alumina copper slag.

Key words: copper slag dilution, Al2O3, phase transformation, Melt structure, Copper loss

摘要： 铜渣贫化是铜冶金工业可持续发展的重要方法。随着优质铜精矿的不断消耗，低品位、高杂质的铜精矿逐渐被利用。高铝铜精矿作为一种典型的低品质铜精矿，其熔炼后的铜渣中Al2O3含量有所上升。随着铜渣成分的变化，控制铜渣特性对在贫化过程中回收铜以及降低铜损失至关重要。本工作以ISASMELT铜渣为原料，采用X射线衍射(XRD)、扫描电子显微镜(SEM-EDS)、红外光谱(FTIR)等分析技术，阐明了火法贫化过程中不同Al2O3含量对铜渣的物相及结构的影响，以及物相转变及结构改变对铜损失的影响。还研究了不同CaO添加量对高铝铜渣的物相转变、结构和铜损失的影响。结果表明，随着Al2O3含量的增加，熔渣中会形成高熔点的铁铝尖晶石，且铝硅酸盐结构也趋于复杂，使熔渣黏度增大，渣中铜含量增加。在高铝铜渣中加入CaO，会形成高熔点的钙铁辉石、钙镁橄榄石，黏度增大。但是随着CaO添加量的增加，熔渣结构趋于简化，黏度降低。在CaO添加量为2wt%时，渣中铜含量最低，为0.78wt%。少量CaO的加入能够降低高铝铜渣的渣中铜含量。

关键词: 铜渣贫化, Al2O3, 物相转变, 熔体结构, 铜损失