Selfrag introduces slag recycling system

Selfrag AG, a maker of high-voltage fragmentation equipment, has developed a process for the commercial recycling of incinerator slag. The company, headquartered in Kerserz, Switzerland, will install its first system at SAIDEF’s facility in Posieux, Switzerland. The installation at SAIDEF, a Swiss-based waste management company, is expected to be operational by the beginning of 2016, Selfrag says.

Selfrag says slag often contains significantly more ferrous and nonferrous metals than those found in natural mineral deposits. The high temperature during incineration causes an agglomeration of the different fractions, which typically has made it difficult to economically recover these metal fractions.

However, Selfrag uses a high-voltage fragmentation process to separate the recyclable fractions. Electrical discharges produced by high-voltage pulse generators create powerful shockwaves that efficiently separation the slag fractions, including the metals. The company says its process significantly improves the quantity and quality of the recycled materials.

By using the new system at its Posieux incinerator, the Swiss waste management firm SAIDEF says it expects to increase recovery of ferrous and nonferrous metals by more than 100 percent and to reduce landfill requirements by up to 30 percent.

Albert Bachmann, CEO of SAIDEF, comments, “Extensive tests convinced us of this new technology. We can double our recovery, especially for nonferrous metals. The recovered metals are cleaner and will generate a higher sales price.”

Bachman adds, “About 5 to 10 percent of the total slag volume is completely cleaned, fulfilling stringent Swiss regulations on inert fractions and can be potentially used as aggregates in road construction, which opens up another income source. The metal recycling, together with the decontamination of the remaining material, will reduce the waste to be landfilled by 20-30 percent, leading to a cost saving of 50 Swiss francs (US$50.60) per metric ton.”

He continues, “There is an additional benefit through the reduction of fossil CO₂ emission from the waste incineration process, a mandatory requirement in Switzerland from 2020.”

Frédéric von der Weid, CEO of Selfrag, says, “Selfrag is a recognized pioneer in the field of electrodynamic fragmentation. Our vision is to establish an economical recycling method for the respectful use of the world’s resources. Thanks to our new slag treatment system, the metals from the waste in Fribourg will be reused instead of being landfilled. We hope that this project is a paradigm shift and will convince other cities too.”

The system in Posieux, with a capacity of 3 metric tons per hour, will be installed in partnership with the Swiss consulting and engineering firm Frei Fördertechnik.

“The partnership between Selfrag and Frei Fördertechnik allows us to offer a combination of state-of-the-art technology with proven systems engineering capabilities within the incinerator and landfill industries,” says Collin Frei, CEO of Frei Fördertechnik. “The partnership enables optimized processing, sorting and conveying of bottom ash, delivering immediate financial benefits and setting a new standard for environmentally friendly treatment of bottom ash.”