In the quest for purer copper, researchers have uncovered a promising method that could significantly impact industries reliant on high-purity copper, particularly in energy and aerospace sectors. A recent study, led by Mohsine Ez-zine from the Mohammadia School of Engineers at Mohammed V University in Rabat, Morocco, and published in the journal Tribology and Materials (translated as Tribology and Materials), has revealed that thermal pretreatment of copper scrap can enhance its purity and reduce refining time, potentially leading to substantial cost savings and improved efficiency.
The research builds on Ez-zine’s previous work, which identified 1120 °C as the optimal melting temperature for achieving high purity from recycled copper scrap. In this phase, the team investigated the effects of thermal pretreatment at various temperatures before melting and casting. “We wanted to see if we could further improve purity and reduce refining time by controlling the thermal pretreatment process,” Ez-zine explained.
The initial approach involved continuous heating with isothermal holds at six target temperatures, ranging from 200 to 950 °C, with holding times of 5, 10, 15, or 20 minutes. This method significantly improved copper purity, increasing it from 99.9230 to 99.9714 wt. %. However, the team noticed substantial mass losses when holding times exceeded 10 minutes, primarily due to the thermal degradation and fragmentation of thin copper wires.
To address this issue, the researchers explored alternative thermal pretreatment techniques using different holding times. One particularly effective refinement involved a holding time sequence of 5 – 5 – 10 – 10 – 15 – 5 minutes at selected isothermal stages. This approach increased purity to 99.9716 wt. % and achieved a thermal conductivity of approximately 362 W/mK, while reducing the total refining time to 94 minutes.
The implications of this research are substantial for industries that require high-purity copper, such as energy and aerospace. By optimizing the refining process, companies can reduce costs, minimize material losses, and improve overall efficiency. “This method not only enhances purity but also makes the refining process more sustainable and economical,” Ez-zine noted.
As the demand for high-purity copper continues to grow, particularly in the renewable energy sector, this research could pave the way for more efficient and cost-effective refining processes. By fine-tuning the thermal pretreatment stage, industries can achieve the desired purity levels while reducing their environmental footprint and operational costs.
The study, published in Tribology and Materials, offers a promising avenue for future developments in copper refining. As Ez-zine and his team continue to explore this method, the potential for further improvements in purity, efficiency, and cost savings remains significant. This research not only advances our understanding of copper refining but also highlights the importance of sustainable practices in the energy sector.