Sustainable process for fully recycling masonry rubble

Masonry rubble  containing brick
© Shutterstock / Aleksashka

Around 60 million tons of building rubble are generated in Germany every year. Besides waste concrete, a large part of this is so-called masonry rubble, i.e. brick fragments, which sometimes have residues of mortar or plaster firmly adhering to them. Brick and mortar or plaster, however, differ fundamentally in their chemical-mineralogical composition, making it difficult to recycle masonry rubble directly.

In order to make full, sustainable use of masonry rubble, it must first be selectively separated into its various constituents. To this end, our experts use both established and new, innovative technologies, which are constantly being further developed in ongoing research projects. 

Closing the material cycle: Processing, recycling and re-using building rubble

Once the rubble has been roughly crushed (e.g. in a jaw crusher), it can be processed by electrodynamic fragmentation (EDF). This process is based on the repeated discharge of ultrashort pulses under water through the material and its resulting fragmentation, preferably along existing grain and phase boundaries. This removes any adhering mortar and plaster residues from the crushed brick.

Fractional screening can then be used to obtain coarse-grained, cleanly-sorted brick. The remaining mixed fine fraction is subsequently cleanly sorted into brick and mortar fractions, for example by real-time optical spectroscopic analysis. Suitable recycling strategies can then be evaluated based on comprehensive analyses of the RC materials obtained.

This means that the resulting brick material can be fed back into production to make new bricks, thus closing a real material cycle. Thanks to the ENSUBA process developed by our researchers, gypsum can also be recovered from the resulting mortar fraction to be re-used by the construction industry.

Competent advice on specific issues

Through the knowledge gained from our research work and our extensive expertise in processing and recycling, we are more than happy to advise you on matters such as

  • Comprehensive solid state analysis
  • Selective separation of masonry rubble or comparable composites
  • Sorting heterogeneous mixtures (also separating particles of the same color)
  • Evaluating suitable strategies for re-use
  • Processing sulfate-containing residues and recovering gypsum