High-temperature insulation wool

High-temperature insulation wool (HTIW), also known as kaowool (a portmanteau of the words kaolin and wool), known as ceramic fiber wool until the 1990s, is one of several types of synthetic mineral wool, generally defined as those resistant to temperatures above 1000°C. The first variety, aluminium silicate fibre, developed in the 1950s, was referred to as refractory ceramic fibre.

Due to the costly production, and limited availability compared to mineral wool, HTIW products are almost only used in high temperature industrial applications and processes.

Humans have used fire for melting and heat treating metals for thousands of years. To ensure safe working with the fire, for melting and working metals (bronze, iron), special refractory materials were needed to enable the handling of liquid or hot metals . To meet the needs of the wide-ranging applications, a large number of shaped, dense materials (refractory bricks, chamotte), shaped heat-insulating materials (lightweight refractory bricks) and unshaped refractory materials (heavy- and lightweight ramming mixes) have been developed, which are used for special high temperature applications. For decades, however, other manmade materials have been used for thermal insulation, glass wool and rock wool being used in the low-temperature range (around 200 °C to maximum 500 °C).

In the 1960s aluminium-silicate-based "refractory ceramic fibre" were launched on the market in Europe. Due to their high temperature-resistance and good technical properties (i.e. good thermal shock resistance and low thermal conductivity), they quickly became the reference for industrial high temperature insulation. Due to the development of new material types the nomenclature of high-temperature insulation wool was redefined in Germany at the end of the 1990s. (VDI 3469.). Although even today the term "ceramic fibre" or "refractory ceramic fibre" is commonly used it is inaccurate in terms of the materials available, their specific properties and limitations.

Thermal insulation with HTIW enabled a more lightweight construction of industrial furnaces and other technical equipment (heating systems, automobiles), resulting in many economic and ecological benefits. Consequences are smaller wall thicknesses and considerably lower lining masses.

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