Many industrial processes produce substantial amounts of wastewater with very high salt concentrations. Covestro and partners from industry and academia are searching for environmentally friendly ways to recover salt and water. They want to use the treated salt and purified wastewater in electrolysis processes to produce chlorine. Chlorine is key raw material for the manufacture of polycarbonate and other plastics.
Ideas include the development of a trace substance analysis in strongly saline solutions, the purification of saline wastewater streams by adapted adsorptive and electrochemical processes, and the use of waste heat from adjacent production plants to increase the salt content of the salt solutions. If all goes well, Covestro will build a demonstration plant for testing purposes at its Krefeld-Uerdingen site in Germany. In early 2016, the company already brought a pilot plant on stream that uses a recycling process developed in-house to purify salt-laden process wastewater so that it can be reused for the production of chlorine.
Other project participants in the “Re-Salt” (recycling of salt-laden industrial process water) project are the German Water Center, Donau Carbon GmbH, the University of Duisburg-Essen University, Dechema-Forschungsinstitut, Envirochemie GmbH, and TH Köln – University of Applied Sciences. Re-Salt is scheduled to run for three years and is funded by the German Ministry for Education and Research (BMBF) as part of the WavE funding measure (funding code: 02WAV1408).
- Covestro, Leverkusen, Germany