Characterization of Copper Slag

Abstract

Copper slag can be treated as a secondary resource since it usually contains a substantial amount of copper and other valuable metals. Characterization of the slags to determine the expected metal recovery is essential for the design of separation flow sheets. In this study, the chemical and mineralogical composition of a copper slag from El Teniente, Chile were characterized. The copper content of the fayalite based slag is around 0.87 wt% which is higher than for certain copper ores. Copper exists as sulfides in the form of droplets in the slag. The content and particle size distribution of the major sulfide phases (bornite, chalcopyrite and chalcocite) were quantified using analytical scanning electron microscopy (QEMSCAN). The copper bearing particles have a wide particle size distribution from a few microns up to mm level. Large copper bearing particles (> 100 μm) are composed mainly of bornite and chalcocite and tend to accumulate in the lower part of the slag layer. As characterized with X-ray computed tomography (CT), around 70 volume% of copper value exist in these large copper bearing particles.

Environmental and Socioeconomic Impact of Copper Slag—A Review

“…Previous research on slag supports this investigation, with researchers from the biggest mining sectors involving copper slag from as far as Chile and Turkey still investigating the reclamation of valuables from copper slag [8,20]. Botswana faces similar problems with high yields of slag produced over time, which have had a high impact on the environment [21].…”

“…Some of these alloys obtained reflect sponge iron properties, which can be pelletized before magnetic separation to get iron. This in turn could be a viable approach toward the recovery of metals [8]. Thus, it I s worthwhile for Chile to take the necessary research steps toward utilizing CS to their advantage and benefit.…”

“…Copper is another important metal, and its current market price is the highest considering the last 10 years [22]. Copper and nickel are usually found in the sulfide phase, and previous research has indicated that the best possible recovery routes involve flotation and leaching, whereas iron can be recovered via direct reduction using coke or other reductants [8,91,92]. Table 3 shows a summary of possible process routes used in previous research for possible metals present in CS.…”

“…It is estimated that 2.2-3 tons of copper slag is generated per ton of copper produced, and this waste is mostly Crystals 2021, 11, 1504 2 of 16 disposed of near smelter sites [5,6]. There are a significant number of copper processing plants around the world, and this has resulted in the production of about 24.6 million tons per year of slag, which is regarded as waste [7][8][9]. The main questions related to this slag are as follows: What does the slag contain?…”

Metal losses in pyrometallurgical operations - A review

“…The different mineral phases in the sample have a different linear attenuation coefficient μ (cm -1 ), which depends on the electron density, the effective atomic number of the material and the energy of the X-ray beam. Wang et al already used this technique to characterize copper slags [80,81]. This technique, however, as it uses Xrays, cannot characterize slags with a high lead concentration.…”