Porosising agents in the Austrian brick industry

In this report, the Federal Environment Agency describes the origin and use of porosising agents in the Austrian brick industry. These additives are added to the raw clay and leave fine air pores when burning, which results in better heat — insulation of the brick. In 2005, 109,733 tonnes of paper — trapping materials, 35,811 tonnes of sawdust and smaller amounts of sunflower — shells, polystyrene and lignite were used as porosising agents. In addition to listing porosing agents currently being used internationally, production waste and their possible recovery are also presented. The report also describes how traditional porosising agents can be replaced by organic substances (e.g. plant fibres or sewage sludge) or inorganic substances (e.g. silica or coal ash).