Recovery of landfilled aluminium

The former aluminium slag landfill in Wiener Neustadt is being cleared and cleaned up by the Bundesaltlastensanierungsgesellschaft (BALSA). In the process, not only are groundwater and the environment protected, but aluminium is also extracted from the landfill as a valuable raw material and recycled. This is done with the help of innovative processes that enable the efficient and sustainable use of resources.

At the Berlin Recycling Congress, those responsible for the project presented their results. Tons of waste were disposed of at the former landfill site in the west of Wiener Neustadt from 1974 to 1991. These caused considerable damage and threatened the Mitterndorfer Senke, one of the largest groundwater resources in Europe. After thorough preliminary work, the total volume of the landfill was determined using a 3-D model. About 1 million tonnes of waste are contained in the contaminated site, more than half of which is hazardous industrial waste. "The waste covers an area of 44,000 square metres, or about ten football fields," said project manager Johannes Czeczil in Berlin.

From the beginning, BALSA worked closely with the University of Leoben, above all with Univ. Prof. Helmut Antrekowitsch from the Chair of Nonferrous Metallurgy and his team. There are 680,000 tonnes of aluminium dross residues stored in the landfill. "With the help of eddy current technology, a total of around 60,000 to 70,000 tonnes of aluminium granulate can be recovered from the landfill. Through further use in aluminium smelting plants, 35,000 tonnes of aluminium can ultimately be returned to the economic cycle. For example, new engines are produced for the automotive industry," explains Antrekowitsch. The environmental balance of the remediation is impressive: A total of around 700,000 tonnes of CO2 will be saved.