Although end-of-life (EOL) batteries are estimated to become a significant source of secondary cobalt in the future, recycled cobalt alone will not be nearly enough to satisfy the increasing demand during the next decade (Alves Dias et al. Over 50% of the world’s cobalt is mined together with copper in the Democratic Republic of Congo (DRC), where small scale artisanal mining is estimated to cover approximately 20% of the country’s mining output and is associated with human rights violations, corruption, and environmental damage (Nkulu et al. In ores, cobalt is usually extracted as a by- or co-product of nickel and copper, which makes the metal vulnerable to fluctuations in the demand for copper and nickel (Olivetti et al. The ongoing transition to electric mobility is projected to massively increase the demand for battery metals, such as cobalt, nickel, and lithium, many of which are considered critical raw materials in the EU (European Commission 2020). Optimal solutions for the concentrate could be found when experimental data on the minerals processing steps becomes available. Based on this, it is suggested that, during hydrometallurgical processing, improved treatment of cobalt-containing wash waters and the optimization of oxygen utilization efficiency in pressure leaching are the most significant ways to decrease the environmental impacts. The impacts were estimated prior to intensive metallurgical testing to determine the possible high impact areas in the process. The simulation showed that there is still potential to improve the cobalt recovery (to approximately 96%), which would also affect the indicator values. The production of a high grade concentrate was observed to greatly decrease the impacts of the hydrometallurgical process, but the cobalt losses in the beneficiation stage and the mineral processing impacts would likely increase. With linnaeite-dominated ores, the equivalent values were 20.4 kg CO 2-eq and 11.0 kg CO 2-eq. With cobaltite-dominated ores ( High As case), the global warming potential (GWP) was estimated to be 20.9 kg CO 2-eq, of which 12.7 kg CO 2-eq was attributed to the hydrometallurgical process. The results indicated that the main cobalt mineral type (cobaltite, linnaeite) had only minor effects on the evaluated impact categories. Uncertainty regarding the possible future raw material composition was studied, and the simulation was used to investigate process performance and to evaluate the effect of variation in the process parameters on the environmental impact indicators. The environmental impact categories (global warming, acidification, eutrophication, ozone depletion, photochemical smog creation, water use) were calculated in GaBi software. The drafted process was simulated using HSC Sim software to obtain a mass and energy balance, which was compiled into a life cycle inventory (LCI). MethodsĪ literature analysis was conducted to establish the state-of-the-art processing methods for complex cobalt ores containing significant amounts of gold. The goal of this study was to evaluate the cradle-to-gate impacts of cobalt sulfate recovery from unutilized cobalt- and gold-bearing ores with the use of process simulation. Such raw materials include complex ores containing minerals such as cobaltite and skutterudite, which, while rare, occur around the world, including in Finland, Canada, and the USA. The soaring demand for cobalt for lithium-ion batteries has increased interest in the utilization of non-conventional cobalt sources.
0 Comments
Leave a Reply. |