Statistics show that less than 1% of the rare earth elements contained in e-waste in Europe are recovered. This makes the region highly dependent on supplies of strategic raw materials from China that could be profitably recovered from e-waste locally. Scientists from Switzerland have taken a step in this direction by creating a technology for quickly and inexpensively extracting rare earth elements from obsolete equipment.
Image source: ETH Zurich
A team of chemists from the ETH Zurich has set themselves the goal of profitably extracting rare earth elements from waste, although technically these same reactions can be used to obtain valuable raw materials from ore. Rare earth elements are chemically bound to other substances in both products and ores, but recycling e-waste is a notch higher in environmental priorities and therefore more important than other initiatives.
The starting point for the research was the study of tetrathiometalates, inorganic molecules containing four sulfur atoms around tungsten or molybdenum. These molecules bind metals in natural enzymes and are even used for anti-cancer therapy and for disorders of copper metabolism in humans. Similarly, tetrathiometalates could be adapted to bind rare earth elements in compound solutions.
Scientists began their work with tetrathiometalates by extracting europium from the phosphor layer of fluorescent lamps. In recent years, Switzerland has been getting rid of fluorescent lamps, including energy-saving ones, sending them to landfills outside the country. Along with the lamps, potentially valuable raw materials are lost, which also end up in landfills. In the process of experiments, scientists developed a technology for the profitable extraction of europium from the phosphor of lamps.
Moreover, the proposed solution helped recover 50 times more europium from scrap than previous alternative processes. Riding the wave of success, a group of scientists created a startup called REEcover to commercialize technology for extracting rare earth elements from electronic waste and promises to similarly extract other rare chemicals that Europe sorely needs from waste.