Innovative HSR process to transform waste incinerator slag into useful mineral additives

The Holderbank Smelting Redox-Process (HSR), which is patented world-wide, was born as a conse-quence of the general need for the reuse of waste and reduction of tipping fees for landfilling. Holderbank Management and Consulting Ltd (HMC) together with the Montan University of Leoben have developed a process to transform slags from municipal waste incineration into mineral additives. Laboratory and semi-industrial tests show its suitability as a mineral additive and the heavy metal compounds in the slag are transferred into usable heavy metal alloys separated from the molten slag. Preliminary estimates of the production costs are comparable with the costs of landfilling in Switzerland. Involved in the industrialisation of the HSR process is Von Roll Environmental Engineering Division, Zurich (specialised in environmental techniques). Moreover, the project is financially supported by the public authorities of Switzerland, comprising the Swiss Federal Ministry of Environment and several cantons. The HSR pilot plant (start-up in June 1995) will remain in operation for 2 years collecting all the relevant data required for planning the first industrial plant which should be in operation in 1998 with a capacity of about 20,000 t.p.a.