Precious metal adsorbers

Recovering precious metals from the effluents of the metal processing industry using textile adsorbers

© Klaus Opwis, DTNW, Krefeld

The project “Precious metal textile adsorbers” is based on innovative fibers - textiles that filter valuable metals from industrial process waters and recycle them commercially. They can recover and recycle palladium, platinum and gold on an industrial scale.

The idea of textile mining originated in the think tank of the German Textile Research Centre North-West (DTNW). The project partners are turning the idea into an industrial application over the course of a two-year project. Central to this project is an innovative so called adsorber textile capable of binding precious metals from industrial process waters and recovering them for commercial use.

The innovative method is able to fix polyelectrolytes permanently and in large quantities to textile substrates. Polyelectrolytes are organic compounds that bind different metal ions. The textile itself consists of polyester and polyvinylamine – inexpensive basic materials that can be combined efficiently. This enables it to filter out different precious metals, especially from process water with low metal concentrations from metal processing industries.

The innovative fibers have already proven their practical feasibility in tests filtering industrial wastewater containing palladium: The palladium was completely bonded and subsequent smelting yielded the pure precious metal. The project “Precious metal textile adsorbers” continues where these tests left off and advances the technological maturity of the process. The adsorber textile is produced on an industrial scale and used to filter industrial process water at a printed circuit board manufacturer. The concept will subsequently be transferred to other unutilized sources of precious metals.