It is essential to minimise environmental harm throughout the entire process. Advancements in recycling technologies are vital for cost-effective and efficient recovery of critical minerals from complex products. This will include innovative hydrometallurgical and pyrometallurgical process techniques to improve extraction rates and the purity of recycled materials (IChemE, n.d.).
A few of these technologies include:
- Water recycling: Conservation and management of freshwater resources has become a major challenge of our societies globally (Kinnunen et al., 2021a). The most important aspect in water recirculation is to ensure that the quality of process waters is kept constant (Kinnunen et al., 2021a). When it comes to water management in mining, an important strategy for mines is the creation of a ‘hierarchy’ of water use, one where varying qualities of water can be put to different uses (“Closing the Loop,” 2018). Re-circulating and re-using water in this way limits the amount of unnecessary treatment that is needed (“Closing the Loop,” 2018).
- Reduced chemical waste: The mining industry heavily relies on a variety of chemicals to efficiently extract and process minerals. Methods like, secondary retention ponds and other measures are designed as part of the mining facility to guard against accidental spillage, and solutions containing cyanide are often treated to reduce the level of cyanide present (The Safe and Effective Use of Cyanide, n.d.). In copper purifying operations, sulphuric acid is recovered through the capture of sulfur dioxide from the purifying preparation, which is at that point changed over back into sulphuric acid (Kinnunen et al., 2021c). This closed-loop framework essentially decreases squander (Recycling Sulphuric Acid in Industrial Production to Reduce Waste and Improve Sustainability, n.d.).
- Improved Tailings Management: Tailings are the non-economical removed from the valuable part of the ore. These have the potential to release acidity and heavy metals into the environment resulting in concerns of the tailings dam stability. The principle of alkali-activation has been tested as a possible mechanism for the valorization of mine tailings as well as a route to immobilize heavy metals often contained in tailings. Also, in order to safely store tailings (that contain sulphides) and prevent acid mine drainage, these tailings have to be shielded from external water flows and oxidizing conditions (Kinnunen et al., 2021c).
Closed-loop systems offer a concrete solution to today’s environmental and economic challenges (Wilkens, 2024).
What system do you use in your operations? Share in the comments…
References:
Closing the loop. (2018, June 27). MIning Decisions. https://www.miningdecisions.com/sustainability/closing-the-loop/
IChemE. (n.d.). Closing the Loop: A Circular Economy Approach to Critical Mineral Sustainability. Retrieved March 25, 2025, from https://www.thechemicalengineer.com/features/closing-the-loop-a-circular-economy-approach-to-critical-mineral-sustainability/
Kinnunen, P., Obenaus-Emler, R., Raatikainen, J., Guignot, S., Guimerà, J., Ciroth, A., & Heiskanen, K. (2021a). Review of closed water loops with ore sorting and tailings valorisation for a more sustainable mining industry. Journal of Cleaner Production, 278, 123237. https://doi.org/10.1016/j.jclepro.2020.123237
Recycling Sulphuric Acid in Industrial Production to Reduce Waste and Improve Sustainability. (n.d.). Retrieved March 25, 2025, from https://www.chemtradeasia.kr/blog/article-detail/recycling-sulphuric-acid-in-industrial-production
The Safe and Effective Use of Cyanide. (n.d.). Society for Mining, Metallurgy & Exploration. Retrieved March 25, 2025, from https://www.smenet.org/what-we-do/technical-briefings/the-safe-and-effective-use-of-cyanide-in-the-minin
Wilkens, P. (2024, November 22). Closed-Loop Systems in the Circular Economy. CGS. https://cleanglobestaffing.com/closed-loop-systems/
