Lime, sand and a small quantity of water are measured and mixed in the correct quantities. This mixture is taken to a reactor in which the quicklime reacts with water. From here this mixture finds its way to the presses where it is pressed into the required forms (bricks, blocks or large format blocks). After pressing, the products are placed on a carriage and driven into an autoclave. Then steam is introduced into the autoclave up to a pressure of around 15 Bar (approx. 200 °C). At this temperature, a chemical reaction occurs between the lime and components of the sand that contain silicon and the product hardens. Once the products have cooled, they can be transported to the construction site and laid. The steam is produced using natural gas, a relatively clean fuel. The steam only needs to be at a temperature of 200 °C to produce calcium silicate. This gives rise to a relatively low use of energy per calcium silicate unit. Approximately 8 m3 natural gas and 10kWh electrical energy are required per ton of calcium silicate products. Production waste is generated in producing calcium silicate. This comprises rejected products and sawing remnants. Nowadays the production waste is largely reused by crushing it and feeding it back into the production process. In doing so, the crushed rubble acts as a replacement for sand. A smaller amount is reused as foundation material in the road construction industry and for improving the slope in the sand quarry. A new application for this crushed rubble is as surfacing for bicycle paths in nature reserves. This application is highly valued because of the natural appearance of the rubble and the very limited maintenance required by the material.
