Seloxium

If everything goes to plan at the start-up Seloxium, mining companies and others seeking to recover precious metals and rare earth elements from wastewater will soon have the option of better—and cheaper—technology. Spun out of the University of Oxford in 2022, Seloxium is commercializing Selectal, a liquid-phase polymer that can be combined with additives such as surfactants to selectively isolate metals in effluent from sources as diverse as agriculture, mining, and heavy industry.Seloxium won’t disclose the polymers and other reagents it works with but says it tailors them to bond preferentially to a specific target metal—say, gold or platinum—in a given effluent. Next, the metal-laden particles are filtered from the wastewater; the purified and concentrated target metal is then isolated from the polymer and precipitant. Existing approaches such as electrochemistry, ion-exchange resins, and membrane filtration come up short in one way or another, says Seloxium cofounder and CEO Christian Peters, who has a PhD in water treatment. “You need a technology that has three things: it has to be extremely fast to handle the large volumes; it needs to be robust and not foul up; and it needs to be very selective.” Selectal checks all the boxes. Two of Seloxium’s cofounders, industrial chemist Steve Colley and University of Oxford professor Nick Hankins, are among the inventors on a worldwide patent published in 2022 that forms the basis of the company’s technology. In the patent description, the inventors state that their technology could cost-effectively treat effluent at concentrations as low as