PYRAL AG owns and operates a pyrolysis plant in Freiberg, Saxony.

This plant synergistically ties together ImCAL’s waste management services, which include:

•     waste procurement,
•     thermal processing,
•     recovery of recyclable materials (secondary raw materials), and
•     the discharge of waste residuals underground or at the corporate Group’s landfill.

Key Input Materials

Various aluminum composites and aluminum laminates (i.e., mixtures of aluminum with glass or with plastics) serve as the key input materials for the pyrolytic process, discussed below. These wastes originate predominantly from the packaging industry.

Effective June 2005, the German Landfill Ordinance mandates that these types of wastes, in addition to numerous other waste materials, must either undergo a mechanical pre-treatment process prior to landfilling or incineration, or be recycled.

The Pyrolysis Process

Pyrolysis is a thermal process whereby organic matter is disintegrated under anaerobic or oxygen-deficient conditions at a temperature of 600° C. Pyral AG’s pyrolysis plant produces three output materials:

•     high quality aluminum briquettes, for further refinement by the secondary aluminum smelting plant;
•     highly inert glass granulates, stabilized and ready for disposal; and
•     synthesis gas, an alternative fuel reused in the pyrolysis process

Starting from a mixed waste stream consisting of aluminum and plastics, ImCAL’s aluminum recovery and waste treatment complex produces high quality aluminum briquettes, achieved through pyrolysis.

In a second, associated process stage, a high-temperature reactor is used to vitrify waste materials - such as pyrolysis coke (which is a direct waste by-product of the pyrolytic treatment process), and other high-priced wastes from various industrial sources. By means of this procedure, waste materials are then converted into highly inert glass granulates.

Synthesis gas (syngas) is a by-product derived from both the pyrolysis and the waste vitrification plants. Syngas serves as a reliable alternative to natural gas and is used to heat the pyrolysis drum to temperatures over 600° C. An added advantage of this economical fuel replacement is that syngas, unlike other fuel gases, does not require a burdensome cleaning process; instead, it can immediately be fed back into the pyrolytic production process, which thus generates fewer waste by-products.


The ability to recycle waste gases and to recover metals is a distinct direct benefit associated with the pyrolytic process. In contrast, other waste incineration facilities are only able to profit from the heat they generate (as a result of the combustion of refuse - which is used to generate electricity).

Sources of Input Materials

With the objective to keep the waste stream composition at ideal levels, ImCAL strives to maintain an optimal balance (mixing ratio) between wastes that contain aluminum and non-aluminum wastes. With this procurement goal in mind, we have assembled a network of suppliers from various segments of the recycling industry. The following sources contribute to a steady and reliable stream of wastes rich in aluminum:

•     Waste sorting facilities associated with Germany’s Binary System (Duales System Deutschland (DSD). The  DSD has the nationwide responsibility for overseeing the separate collection and recycling of packaging materials. From this source, we obtain aluminum-plastics composite wastes;
•     Waste sorting facilities that process PCB-contaminated aluminum cables (with an aluminum content of 80%). Given that they are laced with PCBs, scrap dealers and recycling operators are legally prevented from accepting such wastes (Seventeenth Ordinance on the Implementation of the Federal Emissions Control Act: 17. BImSch). Such wastes can only be recycled via the pyrolytic process.

The recycling of Tetra Packs is of further interest. The deposit duty imposed by the German Packaging Ordinance forces waste sorting facilities to look for (better) ways to process packaging materials, such as Tetra Packs. The incineration of packaging materials (beverage containers) that contain aluminum is no longer considered an acceptable solution today.