Similitude theory considerations in the production of calcium hydrosilicates from lime-rich mixtures

The use of calcium hydrosilicates (CSH) can. open up nero applications which are particularly interesting from the point of view of environmental technology Outside the building materials industry the demand for calcium oxide for CSH in Germany is currently about 25 000 tonnes per year with an upward trend. This article describes the production of a CSI-I with the same structure as xonotlite. Because of the special process the product has a high level of purity which is adequate even when xonotlite is used as a pigment in the paper and die industries. Because of its specific properties xonotlite is also used as an asbestos replacement for fire protection materials and as a means of adjusting the thixotropy when processing plastics. A large number of influencing variables have to be taken into account to achieve a consistent product quality when producing xonotlite. The similitude theory can make a substantial contribution here by describing complex relationships with just a few coefficients. This enables the production parameters to be defined accurately and represented in a single working diagram. The results of the similitude theory considerations can be applied to other CSH phases.