| Summary: | To cope with current trends in the base metals industry due to the lack of pure mining resources, booming metals prices, and growing demand for base metals: new thinking regarding the nature of metal resources as well as novel recycling technologies is needed. Slags from base metals' production can be a superior material for recycling. Currently, at the Rönnskär smelter plant, copper slag is recycled in a continuous procedure, including fuming, settling, and granulation. The main product is called Iron Sand with smaller amounts of matte and speiss. These two phases contain a considerable amount of Cu, Ni, and precious metals. Investigating the distribution of elements and oxides in these separate phases and the effect of CaO as a common impurity, is the main aim of this study. The original materials, including settling slag, matte, and speiss, were delivered by Boliden AB, Rönnskär Smelter Plant. Each material was dried, crushed, milled, and separated in the mineral processing laboratory of Luleå University of Technology for later analysis with X-ray diffractometery (XRD) and thermal treatment. Six different samples were prepared by homogenously mixing these three phases along with different ratios of CaO. Then, the six samples were placed in alumina crucibles and remelted in a Tamman furnace under N2 atmosphere at 1400°C for one hour to attain maximum settling. After cooling, slag, matte, and speiss were carefully separated from solidified material. A fraction of the materials were mounted and prepared for light optical microscopy (LOM) and scanning electron microscopy (SEM) investigations. The remaining material was crushed and milled for X-ray diffractometery (XRD) and chemical analysis. XRD analysis disclosed that the matte and speiss result in very complicated patterns, which are not easily interpreted. Treated samples along with original samples were sent to Rönnskär smelter plant for accurate chemical analysis of Cu, Ni, Fe, Zn, Pb, Sn, Sb, As, Ag, S, Al2O3, MgO, CaO, and Fe3O4. The results of XRD, LOM, ...
|
|---|