Editorial Feature

Reducing the Use of Cyanide in Mining with Glycine Leaching Technology

As the industry aspires to a low-carbon future and the demand for essential metals increases, the sustainability and effective recovery of these resources becomes a worldwide issue. Glycine leaching technology (GLT) tackles many of the mining industry's challenges, assisting miners in recovering metals in a safer, more ecologically friendly, and cost-effective manner than any other available technique.

cyanide, glycine leaching

Image Credit: chemical industry/Shutterstock.com

Environmental Hazards of Cyanide

Cyanide harms the environment and human health by polluting water, contaminating the ecosystem, and disturbing the food chain. Contact with cyanide can also result in respiratory and neurological complications for workers and communities.

When the tailings dam broke at the Aurul gold processing plant in Romania, it released 100,000 cubic meters of cyanide-contaminated water into the Somes, Tisza, and Danube rivers.

Over 2.5 million people in Hungary suffered from polluted drinking water, and the levels of cyanide in the Somes River exceeded 700 times the allowable limit. Affecting people and marine life, the repercussions were far-reaching enough to stir alarm in the industry. It is necessary to find an alternative to cyanide in mining to overcome the adverse effects of cyanide.

Glycine Leaching Technology as an Alternative

Glycine leaching technology (GLT) is inspired by nature. Over a decade ago, researchers at Curtin University in Perth, Australia, observed that plants were absorbing gold and other metals from the soil due to glycine.

Glycine leaching technology operates on a molecular level, where glycine forms stable complexes with metals, facilitating their dissolution from ores. This process is highly selective, allowing for efficient extraction of target metals while minimizing the extraction of unwanted elements.

Real-world examples of mining operations transitioning to glycine leaching highlight the technology's viability. Operations in Australia and Canada have reported successful outcomes, demonstrating the potential of glycine leaching to become a standard practice in the mining industry.

How Glycine Leaching Technology Works

Glycine leaching involves a series of chemical reactions where glycine interacts with metals in ores, forming soluble complexes. This process allows for the efficient extraction of metals, with glycine acting as a selective agent. The resulting metal-glycine complexes are easily recoverable, contributing to the overall efficiency of the mineral extraction process.

Advantages of Glycine

Glycine is an attractive leaching reagent since it is non-toxic and edible. It is a food additive for humans and animals.

Glycine is highly selective about what it bonds with. In mining operations, glycine binds with target metals such as silver, gold, copper, nickel, and, in certain situations, platinum group metals. It does not form bonds with gang metals, such as iron, mercury, lead, or arsenic, which must be removed during the procedure to avoid environmental problems.

Compared to cyanide, a powerful leaching agent that efficiently extracts gold and other metals, glycine is far more selective and recyclable. 

Environmental and Health Benefits of Glycine Leaching

The transition to glycine leaching also addresses concerns regarding worker and community health. The non-toxic nature of glycine eliminates the immediate health risks associated with cyanide exposure, fostering a safer working environment. By prioritizing the well-being of those involved in mining operations, glycine leaching contributes to the industry's social responsibility and sustainability.

A comprehensive comparison of the environmental footprint of glycine leaching and traditional cyanide-based methods underscores the environmental benefits of adopting Glycine Leaching Technology. Reduced water and soil contamination, lower carbon emissions, and decreased dependence on hazardous chemicals make glycine leaching a more environmentally sustainable choice for mineral processing.

Efficiency and Cost-Effectiveness of Glycine Leaching Technology

Glycine leaching offers competitive efficiency compared to traditional cyanide-based methods. Studies have shown comparable extraction rates, with the added benefit of reduced energy consumption. While initial adjustments and investments may be required to implement glycine leaching technology, the long-term economic and environmental benefits make it a cost-effective and sustainable choice.

While the initial investment in adopting glycine leaching technology may be higher than traditional methods, a comprehensive cost analysis reveals the long-term economic benefits. Factors such as reduced environmental remediation costs, lower health and safety expenses, and potential revenue from eco-conscious consumers contribute to the overall economic viability of glycine leaching.

Current Limitations of Glycine Leaching Technology

Despite its promise, glycine leaching technology is not without its challenges. For example, it is still in its early stages of adoption, there can be variations in efficiency, and it is difficult to scale.

The biggest challenge of glycine leaching technology is that it is new, and an entire mining industry is trained to use cyanide. Glycine leaching technology is a new chemical approach that requires re-training of the industry to use it as an efficient and sustainable approach, and adapting to a new technology can be time-consuming.

Ongoing Research and Future Prospects

Ongoing research and development efforts are crucial to address the existing limitations of glycine leaching technology. Collaborations between researchers, mining companies, and technology developers aim to enhance the efficiency and applicability of glycine leaching. The mining industry's commitment to overcoming these challenges underscores the collective determination to transition to more sustainable practices.

Glycine leaching technology is one example of emerging technologies aiming to revolutionize mining practices. Ongoing research and development continue exploring novel approaches, such as bioleaching and electrochemical methods, each with unique advantages. The evolution of these technologies collectively contributes to the industry's journey toward sustainability.

The Future of Glycine Leaching Technology in Mining

In conclusion, shifting from cyanide-based mining to glycine-leaching technology is crucial for a more sustainable and responsible mining industry. The environmental and health benefits, technical advancements, and economic considerations associated with glycine leaching underscore its potential to revolutionize global mineral-processing practices.

References and Further Reading

Barani, K., Kogani, Y., & Nazarian, F. (2022). Leaching of complex gold ore using a cyanide-glycine solution. Minerals Engineering, 180, 107475. https://www.sciencedirect.com/science/article/abs/pii/S0892687522000851

Sarvar, M., Tonkaboni, Z. S., Noaparast, M., Badiei, A. R., & Amiri, A. (2023). Application of amino acids for gold leaching: Effective parameters and the role of amino acid structure. Journal of Cleaner Production, 391, 136123. https://www.sciencedirect.com/science/article/abs/pii/S0959652623002810

Altinkaya, P., Wang, Z., Korolev, I., Hamuyuni, J., Haapalainen, M., Kolehmainen, E., & Lundström, M. (2020). Leaching and recovery of gold from ore in cyanide-free glycine media. Minerals engineering, 158, 106610. https://www.sciencedirect.com/science/article/pii/S0892687520304301

Johnson, C. A. (2015). The fate of cyanide in leach wastes at gold mines: An environmental perspective. Applied geochemistry, 57, 194-205. https://www.sciencedirect.com/science/article/abs/pii/S0883292714001279

Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.

Usman Ahmed

Written by

Usman Ahmed

Usman holds a master's degree in Material Science and Engineering from Xian Jiaotong University, China. He worked on various research projects involving Aerospace Materials, Nanocomposite coatings, Solar Cells, and Nano-technology during his studies. He has been working as a freelance Material Engineering consultant since graduating. He has also published high-quality research papers in international journals with a high impact factor. He enjoys reading books, watching movies, and playing football in his spare time.

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