Approximately 200 kilograms of raw materials per capita per day are consumed by the German Federal Environmental Agency. This puts us at the top of the world. This not only harms the environment - it is also dangerous to our international competitiveness. As a resource-poor country, Germany must rely on a particularly careful use of resources. New and efficient recycling processes are one way to make yourself more independent from importing expensive and scarce raw materials. Important foundations for the consistent recycling and production in cycles have been laid by Fraunhofer experts in the day after tomorrow project "Molecular Sorting for Resource Efficiency". At the fair IFAT, they present new methods that enable the recycling of precious metals, rare earths, glass, wood, concrete and also phosphorus.

Recycling 2.0 - perfectly separated

"The separation processes take place for the first time at the smallest required level, that is, we go down to the molecular or even atomic level," explains the coordinator of the project, Professor Jörg Woidasky from the Fraunhofer Institute for Chemical Technology ICT in Pfinztal near Karlsruhe. One example is microbial ore leaching, which is being developed for application at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart. This also allows small amounts of precious metal or rare earths to be recovered. The researchers use microorganisms to convert insoluble metal compounds in ores, incineration slags or waste wood soaked in metal salts into water-soluble salts. The dissolved metals can then be bound with special polymers and thus selectively removed from the solution. In a third stage, the metals are separated.

Experts from the Fraunhofer Institute for Silicate Research ISC in Würzburg are working on a process to extract high-quality, dye-free glass from old flat glass. Ultra-white glass allows maximum light transmission and is therefore used in photovoltaics, in fiber optic cables, or displays. If foreign atoms - such as iron - are in the glass, its permeability decreases. "The growth momentum, especially in photovoltaics, is so great that neither the natural, iron-free raw material sources, nor the amount of recycled" old "PV modules, are sufficient to meet the demand for highly transparent flat glass in the coming decades," says Dr. Jürgen Meinhardt from the ISC. An alternative source of raw materials could be conventional flat glass. However, the iron content of the glass is too high. Researchers are developing a process that allows iron atoms to be extracted directly from the liquid hot 1500-Celsius melt.

Use old wood intelligently

In Germany, wood recycling is still in its infancy: So far, only about 33 percent of the annually about eight million tons of wood waste are used. One reason for the low recycling rate is the waste wood regulation. It stipulates that material coated with organohalogen compounds or wood treated with wood preservatives must not or only to a very limited extent be reused. New separation techniques at the molecular level are intended to remedy this without jeopardizing the precautionary idea of ​​the waste wood ordinance.

To be able to recycle waste wood more strongly, one must recognize existing pollutants. Researchers from the Fraunhofer Institute for Wood Research - Wilhelm-Klauditz-Institut, WKI in Braunschweig used various methods such as near-infrared spectroscopy, X-ray fluorescence analysis or ion mobility spectrometry. If the pollutant is identified, you can also remove it. »Wood treated with organic wood preservatives can be cleaned with supercritical fluids. In order to separate or enrich heavy metals, we want to use both wet-chemical and combustion processes and pyrolysis processes, "says physicist Peter Meinlschmidt from the WKI.

Recycle concrete

Several million tons of construction waste are generated every year. A process for recycling concrete does not yet exist. Researchers at the Fraunhofer Institute for Building Physics IBP in Holzkirchen want to change that. They rely on "electrodynamic fragmentation," where ultrashort lightning bolts are chased through the concrete. It enables the concrete to be broken down into its individual components - gravel and cement stone. A first decisive step towards recycling old concrete.

Recover germanium and phosphorus

But valuable materials can not only be obtained from solid waste. The exhaust gases from waste incineration plants also contain raw materials. In order to enrich this, the researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden are developing special ceramic filters on which certain constituents in the exhaust gas are first selectively separated at temperatures of more than 850 ° C and then recovered - for example germanium, zinc and also phosphorus.

But are these developed methods actually suitable for a rapidly changing market environment? The Molecular Sorting partners have investigated this in a study. Your conclusion is positive. Recycling at the atomic level is highly likely to be meaningful in the future. Not only if it is promoted politically, but also as an economically independent business model.

Further information:
http://www.molecular-sorting.fraunhofer.de