A recent study published in the journal Science pointed out that the annual output of domestic mines in the United States could meet the domestic energy, defense and high-tech industries’ demand for all key minerals, such as cobalt, lithium, gallium and various rare earth elements (neodymium, yttrium, etc.). However, these resources are discarded in large quantities as tailings during the mining production process and cannot be effectively recycled.
Colorado's Summit Mine, which produces about 30 million pounds of molybdenum annually, was one of the U.S. mining projects evaluated in a critical minerals analysis published in the journal Science. Image source: Colorado School of Mines
The research was led by Elizabeth Holley, associate professor of mining engineering at the Colorado School of Mines. She said that the key to the problem lies not in resource reserves, but in the recycling process: "These minerals are as difficult to extract as salt mixed in dough. A large amount of research and development and policy promotion are the prerequisites for achieving cost-effective recycling." The team first established an annual production database of all federally licensed metal mines in the United States, combined with data from the United States Geological Survey, Australian Geosciences and the Canadian Geological Survey, and used sampling statistics to estimate the total amount of key minerals abandoned by tailings every year.
Research results show that by recycling only 1% to 10% of cobalt, germanium and other elements currently in tailings, all the needs of the U.S. battery and chip industries can be met. Most key minerals have achieved import substitution, and only platinum and palladium have significant gaps. Take cobalt as an example. As a key raw material for electric vehicle batteries, cobalt is often discarded as a by-product in nickel and copper mining. Less than 10% of it is recycled to supply the U.S. battery industry. Germanium is also enriched in zinc ore and molybdenum mine tailings, and less than 1% can be recycled to fully meet U.S. demand.
The study emphasizes that strengthening the mine recycling belt has two major benefits: First, it is economic and geosecurity benefits; second, it greatly reduces the risk of environmental pollution caused by tailings stockpiling, and it can also promote the recycling of resources in construction and other fields. Holley suggested that relevant policies should encourage mining companies to add supporting processing facilities, because it is difficult to drive manufacturers to actively invest solely relying on market price promotion. "We have discovered the low-hanging fruit of industrial recycling. Next, we need to analyze the minerals occurring in key minerals in detail and test specific technical routes based on mineralogy to separate 'salt' from specific minerals."