As our societies move away from fossil fuels, vast quantities of many types of metal will be required. Demand is rising rapidly, especially for the family of rare-earth metals, or rare-earth elements (which are fairly abundant, but distributed in low amounts so that purifying them requires processing enormous amounts of raw ore). These metals are used in many applications, including catalysts to refine petroleum; to relay signals through fiber-optic cables; for color computer screens, strong and reliable magnets, tracers in medical devices, and even agricultural fertilizers.
According to knowledgeable researchers, metals that are in use, in infrastructure, or in waste can make up much, if not most, of the metals that we need. Scarce metals such as the rare-earth metals and precious metals like gold and silver can be used near-indefinitely. Emerging technologies are making this increasingly possible.
Traditional mining to obtain new metallic ores frequently results in tremendous harm to pristine environments and indigenous people. Mines are often in countries with low environmental standards, and deforestation, contamination of land and water, and human rights violations are common. Mining produces tremendous amounts of waste, or tailings. Researchers estimate that extracting 1 metric ton of rare-earth elements creates about 2,000 metric tons of waste, including 1 ton of radioactive waste. Improperly managed processes in refining rare earth ores can also have serious environmental consequences.
Open cut hard rock mining for gold in Kalgoorlie, Western Australia, 2005 (Wikimedia)
Simultaneously, a “tsunami” of electrical and electronic equipment is being discarded, producing e-waste that contains both valuable and hazardous materials. This results from a combination of our consumption-driven societies, coupled with rapid technological innovations and planned obsolescence, engineered so that consumers will purchase new products. We produce tens of millions of tons of e-waste annually, much of it toxic, and the volume will likely continue to rise precipitously.
Currently, most e-waste is disposed of in incinerators and landfills. The United States and Europe export a significant volume of their end-of-life electronics to developing countries, primarily in Asia and Africa. There, people disassemble components, saving copper, aluminum, and other valuable metals, and then burn and landfill the remaining materials. During these informal recycling procedures, the toxic chemicals released create considerable environmental and human health risks.
A young man burning electrical wires to recover copper at Agbogbloshie, Ghana, as another metal scrap worker arrives with more wires to be burned, 2019 (Wikimedia)
It doesn’t have to be that way. Given the glaring problems with “business as usual”, some governments and industries are moving towards putting metal-associated economies on a more sustainable future—one in which the needs of the present can be met without compromising the ability of future generations to meet their own needs. We are slowly moving towards a circular economy, in which the waste of one product or process loops back to become the input for another.
But there are challenges – and a long road ahead.
Sources of Materials
A recent article I read in a Geological Society of America publication (Wessel et al, 2024) states “The push for critical minerals…provides an opportunity for mining to be part of a circular economy. A paradigm shift is necessary along with higher standards to bring all those affected together around a twenty-first-century stance that values place, people, justice, and legacy”. Important goals to pursue, IMO!
Moving toward a sustainable, circular economy can be implemented by minimizing waste, repurposing or recycling discarded materials, and reducing the demand for new raw materials. Avoiding opening new mines and seeking new discoveries will require prioritizing alternative sources of mineral resources.
Recycling – aka “Anthropological Resources” and “Urban Mining”
E-waste encompasses a diverse array of equipment, with dozens of different chemical elements found in this waste. Many of the metals are in tiny quantities and are mixed with other elements, such as in touch screens. Nonetheless, efficient separation makes the metals in e-waste far more abundant than in newly mined ores. Recycling magnets in electric motors, for example, can concentrate the rare-earth elements to percentages, whereas ore only contains them in parts per million.
There are two main approaches for processing e-waste to separate valuable elements. The first is pyrometallurgy, in which materials are heated to extremely high temperatures (1,830 F /1,000 C degrees and higher) that burn away plastics and other unwanted materials, purifying a portion of molten metals. A major disadvantage is the high energy input required. The second approach, a hydrometallurgical method, uses hydrochloric acid and other strong acids to dissolve metals and then separate them. Disadvantages of this approach include acid-laden toxic sludge and enormous quantities of wastewater.
For both recycling approaches, the associated costs can mean traditional mining is more economical. Fortunately, clever chemists and material scientists are working on sophisticated new methods that could tip the balance in favor of recycling.
Currently, the biggest competitor for recycling is landfills. IF there were strict controls on landfill deposition of e-waste—and enforcement of export restrictions to prevent e-waste generated in high-income nations from being delivered onto the shores of lower-income nations—then more competition for cost-effective recycling services will be created.
E-waste, 2017 (Wikimedia)
Reworking and Remediating Mine Waste
At active and abandoned mine sites, existing waste streams or tailings offer opportunities to re-utilize material. New technologies are making more thorough ore extraction workable. Reprocessing waste streams, even from active mines, can produce additional valuable ore. Abandoned mine waste may contain elemental concentrations that have become valuable, or they may host elements that were not valued until recently. Also, since many abandoned sites require remediation to mitigate environmental impacts, reworking the mine waste can be part of the remediation.
Moving Forward
Conventional exploration and development practices to open new mines should be a last resort. When clearly necessary, all impacts should be fully mitigated, with no long-term adverse effects on society or the environment. Reducing demand is also of utmost importance—and consumers have an important role. Electronics engineers need to design devices that maximize easier repair and disassembly.
Tall orders for the mining and electronics industries, but not unimaginable! Forward-looking people are developing protocols for twenty-first century mining practices. Eventually, a universal protocol is possible that can be applied everywhere on our planet. An excellent place to start is in the United States.
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A very interesting post, and timely. Thank you. I am not a geologist but have an interest in the field.
Thanks for your comment, Deborah!
As you say, “a tall order”. We need to find a way to clearly communicate the overall cost, beyond the 2000 to 1 ratio in your example. As you note, the true cost of recycling, the cost of mining… trucks, processing, labor, shipping waste, disposal, etc. Thank you for bringing attention to the situation.