Sustainable Technologies for Calcined Industrial Minerals in Europe
Stoicism is a European project focused on developing a more efficient method of calcining minerals for use in industry. We have developed a combination rotary kiln that uses both radiant heat and microwave heating to process a variety of materials used in the chemicals, fine chemicals, and building materials sectors.
Significant design and engineering challenges were addressed relating to the incorporation of microwave heating in a rotating kiln. The design features special microwave inlet ports and microwave choke seals designed to prevent stray microwave field escaping. The flights of the rotating barrel are designed to maximise the absorption of microwave energy by the tumbling material. Specialist high temperature materials are used in the kiln construction. The rotating barrel of the unit is 4 metres long and the complete installation weighs 3 tonnes. It operates at up to 1050 °C.
The efficiency of a conventional rotary kiln for mineral calcination is improved by introducing additional microwave heating. This facilitates the removal of bound water. The kiln is heated with 21 kW of radiant power plus an additional 12 kW adjustable microwave input and is designed to process a variety of materials including kaolin, diatomaceous earth and perlite, with specific operating parameters to achieve the required mineral quality.
Co-funded by the European Union under the FP7 programme