In this blog post, we will examine how geochemical exploration using plants can contribute to reducing environmental damage during rare metal development.
The Department of Energy Resources Engineering is a field of study that researches the entire process from exploration, processing, production, and use of energy and resources essential to human life, all the way to post-use treatment. The scope of engineering and scientific knowledge required for these processes is extremely broad. Consequently, many laboratories are responsible for various research areas. This article focuses on geochemical exploration conducted by the Applied Geochemistry Laboratory among these diverse research fields.
In the 2010s, the resource term ‘rare earth elements’ emerged as one of the key economic keywords. Rare earth elements, also known as rare metals, are trace metals constituting less than 0.1% of the Earth’s composition. Though present in very small quantities, their applications have increased significantly in recent years, drawing considerable attention. This is because these rare metals are essential for vivid displays, fast communication speeds, and the proliferation of advanced technologies. There are two key characteristics to understand regarding rare metal production. First, the quantities of rare metals are very small. Second, despite this, they exist in small amounts almost everywhere on Earth. This means that even in South Korea, which was once considered resource-poor, it is possible to produce useful metals. However, indiscriminately digging up soil to collect and analyze samples for these metals can cause massive environmental destruction and resource waste. The quantities are so small that even after excavating several tons of earth, it’s difficult to obtain enough rare earth metals for just one smartphone. So, how can rare earth metals be efficiently explored and developed?
The solution proposed by the Applied Geochemistry Research Laboratory involves utilizing plants. When ore bodies (aggregates of minerals) containing rare earth elements exist near the surface, they increase the concentration of these elements in the surrounding soil through weathering. Plants with roots in this soil naturally absorb and concentrate the elements present. By analyzing samples from plant stems, leaves, and roots, the potential for rare metal development in the area can be assessed. This is because plant tissue samples contain much higher concentrations of rare metals compared to soil samples.
This exploration method is already being used for detecting and remediating heavy metal contamination. As plants grow, they absorb heavy metals from the soil and concentrate them within their bodies. This allows us to determine the extent of heavy metal contamination through plant samples and also achieve a purifying effect by reducing the concentration of heavy metals in the soil. Cultivating plants in heavy metal-contaminated areas causes the heavy metals in the soil to migrate into the plants, thereby purifying the soil. This allows for the environmentally friendly restoration of heavy metal-contaminated areas using plants. While these plants are not suitable for consumption, they can contribute to creating forests in barren environments, transforming such areas into recreational spaces.
The Applied Geochemistry Research Lab is conducting research that utilizes plants to detect the behavior and dispersion patterns of chemical components. Not only rare earth metals but also common mineral deposits like iron and copper can be explored through plants. Plant component analysis is also effectively used in the exploration of energy resources such as oil and gas.
China accounts for 96% of the world’s rare earth production and has weaponized these rare metals as resources by leveraging this monopolistic position. However, the severe environmental destruction caused by rare earth production is a significant problem. As an IT powerhouse, South Korea relies on imports for over 95% of the rare metals essential for manufacturing advanced devices. Therefore, securing stable supplies requires not only overseas resource development but also the exploration and development of rare metals existing domestically. Efforts by applied geochemists to secure rare metals without burdening the environment will continue.
