What is perlite?

The name perlite is the scientific term for the chemically and physically transformed material obsidian which is thus counted as a stone. In common parlance the term »volcanic glass« is also used. Perlites have been known as a building material and in agriculture for thousands of years.

Perlites are a natural raw material

During the course of transformation the hard obsidian is broken down by small cracks into glass beads or shards roughly the size of a pea; it then exhibits the typical perlite properties.. As soon as the cracks come into contact with water devitrification commences.

Through the formation of small crystals (quartz, cristobalite and feldspar) a stone is created from the amorphous glass blueish-green, brownish or grey in colour.

Properties of the raw material perlite

Perlite contains up to 2 % water and as raw perlite has a bulk density of around 900 to 1,000 kg/m³. In a thermal treatment process perlite is brought to a glowing state at temperatures of up to 1,000 °C. During this expansion process the volume of perlite increases 18 – 20- fold.

With a bulk density of 50 to 100 kg/m³ a thermal conductivity of λ = 0.040 to 0.070 W/(m K) is achieved. The XERAL building materials technology provides optimization of the thermal conductivity to values of up to λ = 0.028 W/(m K). In addition to optimum values in the sector of thermal protection perlites fulfil the highest demands in fire prevention and provide for a regulated indoor climate.

Perlite and XERAL

Perlite is found in XERAL building materials for numerous applications in the sector of thermal insulation for modern buildings and for home construction. Special treatment procedures and specifically developed production processes for XERAL products allow maximum exploitation of perlite potential.