Research into the Microstructure of Industrial Copper-Containing Slags

Abstract

In the article, the results of a microstructural examination of industrial slags are presented. The slags generated in a copper smelter comprise those obtained from the lift tube of a Vanyukov furnace (VF), copper-rich converter slags and slags obtained following settlement in a VF electric mixer. The phase structure of slag samples taken from the plant and hardened after remelting under laboratory conditions is considered. The composition of matte inclusions and concentration of dissolved copper in the slag was investigated by means of electronic microanalysis taking into account the ratio between the dissolved and mechanically-combined forms of copper present in the slag. A study of the distribution of matte inclusions by size in all types of slags was carried out. It was shown that, for the richest of the investigated slags, comprising converter slags and slags from the lift tube of the VF, the proportion of copper in the form of matte inclusions is noticeably higher than the proportion of copper in dissolved form, reaching 80–85% of the total copper content in the slags. In this case, the main volume of matte suspension in these slags is represented by droplets having a size of more than 100 microns. Although the proportion of the mechanical losses of copper with slag from the electric mixer is noticeably lower, it nevertheless remains significant at up to 50% of the total loss of copper with slag. In contrast to converter slags and those obtained from the VF lift tube, the matte suspension in the slags from the electric mixer is represented by significantly finer particles with a particle size of lower than 50–70 microns. The content of dissolved copper in the studied slags was determined, with the highest content observed in converter slags at 0.77 and 0.87%. The copper content in the form of matte droplets was 67.76 and 74.42%, respectively. The lowest content of dissolved copper was obtained for slags after an electric mixer, which amounted to 0.51 and 0.62% for the studied samples.