Glass stands for resource efficiency and sustainability like hardly any other material, as it has the highest material recycling rate after steel. The recycling of waste glass in the glass melting process leads to a significant reduction in the energy and resource requirements of the glass processing industry.
In the area of container glass, the recycling cycle in Germany is almost closed and recycling rates of up to 90 % have already been achieved. However, used glass is not always the same as recycled glass, which harbors risks for the desirable closing of the materials cycle. In the course of recycling, for example, different types of glass may be mixed together, for example as a result of faulty throw-ins. In particular, contamination of the used glass by glass containing heavy metals, such as lead glass, can lead to an undesirable accumulation of heavy metals in the container glass without reliable control and sorting processes. To effectively counteract this, Keylab Glastechnologie is working on ongoing projects with industrial partners to further develop and refine such detection methods.
In addition to the separation of raw material streams, the recovery of heavy metals as important raw materials is another field of research at Keylab Glass Technology. For this purpose, detailed investigations are carried out, in particular on liquid-liquid and gas-liquid extraction processes, with which lead oxide recovery rates of over 90 % in post-consumer glass have been achieved.
The knowledge gained is not only used in almost closed material cycles of short-lived container glass. Keylab Glass Technology is also researching and expanding the application possibilities of these technologies in the field of purification and upcycling of secondary glass raw materials and long-lived postconsumer glasses, such as flat glass.
Through practical research, risk potentials due to an accumulation of toxic substances, such as heavy metals, in glasses are reduced and, at the same time, a dissipation of these often valuable raw materials in the glass cycle is counteracted. The increased quality of the recycled glass can also increase the acceptance of this valuable secondary resource in other areas of the glass industry.