Process water from the recycling of waste concrete by pulsed power processing
Besides water, concrete is the world's most widely used material. Thus, every year approximately two billion tonnes of waste concrete accrue worldwide, and 900 million tonnes of waste concrete accrue every year in America, Europe and Japan alone. Disposal of this waste concrete or the reuse as sub-base for roads is not a very sustainable option. Recovering of concrete would reduce environmental costs and the unnecessary landfill of valuable materials. Additionally, it preserves our primary resources by regaining raw materials for new building materials. The crushing of concrete by mechanical methods leads to products that consist of gravel with adherent cement stone. Reusing these recycled secondary aggregates in new concrete causes various drawbacks for the concrete, such as reduced mechanical strength and higher demand of water. With the technology of electrodynamic fragmentation, a specific pulsed power process, it is possible to separate the cement stone from the aggregate and therefore, the gravel could easily be reused in new concrete. This pulsed power process is an underwater process and for an effective continuous operating it is necessary to treat the resulting process water in a suitable way.