Rotary kiln

The rotary kiln furnace is essential for the recycling process for a wide variety of products and materials. Examples are the removal of plastic and paint in UBC (Used Beverage Cans) as well as cooling lubricant from copper shavings or the removal of separator films in the black mass of Li-Ion batteries or the simple drying process of wet materials of any kind. The furnace can process materials with a high organic content and uses the energy to produce a large amount of the heat needed for the process. The plant is scalable for the desired throughput. Dependent on the material, throughputs of up to 20 tons per hour can be achieved.

The material gets filled into the rotating kiln which has hot process gas flowing through it. The constant rotation and the tilted drum cause an even pyrolysis and convey the material through the kiln. The organic components are sublimated, carried away with the airflow and used energetically which creates a large part of the energy needed for the process and can reduce the consumption of inert gas.

We developed an electric heated furnace as well as a gas heated one. While the electric heating transmits its heat through heat radiation on to the drum and from there on to the material, the gas heated furnace heats the process gas which then heats up the material convectively. For best energy efficiency and a reduced consumption of inert gas we also developed a hybrid version.

The pyrolysis drastically improves the metal yield by reducing the amount of oxides that result in the melting process. With UBC we reduced the metal loss by 21.4 % due to the pyrolysis. Even more energy can be saved by directly connecting the rotary kiln furnace to a melting furnace. That way the material is already warm when going into the melting process which can save around 35 % of the energy.