| 摘要 |
<p>A method and apparatus for heat treatment of expansible materials to form lightweight aggregate is disclosed. The material is heated within a kiln to a temperature less than that required for optimum expansion. Then the material is further heated by application of microwave energy to complete its expansion. Typically, initial heating of the material is performed in a kiln to a temperature below an optimum expansion temperature of the material. Subsequently, microwave energy is applied either within or externally of the kiln. The method and apparatus can be used with a material such as slate chips, shale, clay or other material. It may be mixed with a refractory material that is microwave-transparent, such as alumina or bauxite.</p> |
