Recycling carbon-rich residues in a versatile and sustainable way

High-carbon residues from tyres
© Shutterstock / AevanStock

Particularly when waste is thermally processed in the absence of oxygen (pyrolysis), residues with a high carbon content are produced. Depending on the feedstock, these so-called carbonisates (or pyrolysates) can be used as a valuable base material for industrial processes or as a carbon sink for technologies with a positive impact on the climate.

Recovered Carbon Black: Closing the material cycle through demineralization

Carbon black (CB), one of the main constituents of tires or rubber articles as well as of colorants in the plastics industry, is a high-tech product that seems to be essentially “unproblematic” when viewed from an ecological perspective. Of the more than 15 million tons of carbon black produced worldwide each year (and rising), 80 percent is used to make technical rubber / tires.

When scrap tires are pyrolyzed, recovered carbon black (rCB) is obtained as a solid by-product. For every ton processed, about one-third is carbon black - which could be reused in industry, but so far has not been an adequate alternative to primary carbon black. One of the main reasons for this is the high mineral “ash” content, which usually includes zinc sulfides, zinc oxides, silicon dioxide, aluminum oxides and, for example, cobalt compounds.

Larger quantities of recovered carbon black can only be used if the mineral residues are removed - but without significantly altering the properties of the rCB. With this in mind, our experts have developed a demineralization process that takes into account both economic and ecological aspects and makes it possible to close the material cycle. 

Pyrochar (vegetable char) as a basis for innovative building materials

The pyrolysis of partly organic residual materials (e.g. plant residues, cuttings, sewage sludge or packaging material) results in the formation of gaseous and liquid products of pyrolysis as well as so-called pyrochar (also known as vegetable char/biochar). This is a solid with a high carbon content. Because this carbon is derived from organic material - and thus originally from atmospheric carbon dioxide - pyrochar is considered a carbon sink. It is an important negative emissions technology (NET, carbon capture and storage CCS) in terms of measures to combat climate change.

Our researchers are constantly working on strategies and methods for processing and using special pyrochars. In addition to exploring ways to refine the chemical composition and morphology of the chars, we are also developing climate-friendly products for future use in new types of building materials.

Are you looking for suitable ways to use your pyrolysis products or do you operate pyrolysis plants and want to refine your pyrochars? Then get in touch with us - we are looking forward to hearing from you!


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