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Recycling
You will soon find more information on the recycling application area here.
Valuable resources must not be wasted
Electronic waste makes up a significant proportion of recyclable waste. Every year, around 50 million tons of it is generated worldwide. Valuable materials that can be recovered as secondary raw materials are also of interest to industry. These are valuable resources that must not be wasted. On the other hand, it contains a large number of highly toxic and environmentally hazardous substances that are released during recycling. This is one of the reasons for the relatively low recycling rate of 20% (in Germany 2.4 million tons / 43% recycling rate). In order to achieve the politically prescribed collection rates and reach the long-term target of 100%, new recycling processes are required. One of the most promising approaches is pyrolysis, as it produces a concentrate with a high copper content and high-quality by-products.
The challenge of achieving a recycling rate of 100%
A new process for the resource-efficient recycling of PCB scrap using microwave pyrolysis in a rotary kiln and the necessary plant technology must be developed in order to achieve a recycling rate of up to 100% for PCB scrap in Germany.
Pyrolysis: High energy efficiency and short treatment times
Pyrolysis enables more efficient mechanical post-processing of the printed circuit boards and thus the production of a metal concentrate containing copper and precious metals with a metal content > 45 %. The adhering organic material is converted into a combustible pyrolysis gas with a calorific value > 18 MJ/m³. Other by-products can be used, for example, in the cement industry and to reduce metallurgical slags
Our solution for process development
Fricke und Mallah, together with the Institute for Metallurgical Process Engineering and Metal Recycling and the Institute for Industrial Furnace Construction and Heat Engineering at RWTH Aachen University, and funded by the German Federal Ministry for Economic Affairs and Energy (reference ZF4042207RE7), has designed and constructed a laboratory device for the process development of microwave pyrolysis of printed circuit boards.
All information at a glance
The device has 8 generators with 6 kW each and works with magnetron technology and 2455 MHz at up to 1000° C. It contains an outer, gas-tight and fixed jacket housing that reflects the microwave radiation and holds it in place, as well as an inner, gas-tight and microwave-permeable rotating tube in which the goods can be transported and high-quality pyrolysis gases can be obtained. Connections for introducing and removing nitrogen are also included.
Innovative advantages over conventional solutions
Compared to conventional, gas-heated rotary kilns, a high level of energy efficiency was achieved when coupling the thermal energy, as at least 80% of the microwave radiation is converted directly into thermal energy in the volume of the material, meaning that the entire rotary kiln does not have to be heated. The throughput of the industrial-scale systems for this process is ≥ 0.25 t/h.
Incomparable with previous solutions
Compared to conventionally heated rotary kilns, the system achieves up to 7 times higher heating rates and thus avoids unwanted pyrolysis oil. In addition, measurement and control technology adapted to the new process was developed to ensure trouble-free operation of the entire system.
Our case studies
Recycling printed circuit board scrap
Have we convinced you?
