Promat high temperature insulation - Further heat insulation materials

CALCIUMSILICAATMATERIALEN

Lightweight calcium silicate boards

Calcium silicate products are manufactured by a hydrothermal process with the finely ground raw material lime (Ca0) and sand in a water suspension with a low proportion of solid material and reinforcements. The mineralogical conversion into the mainphases tobermorite 5Ca0 · 6Si02 · 5.5 H20 (approx. 10 % H20; constant up to 650 °C) and Xonolite 6Ca0 · 6Si02 · H20 (approx. 3 % H20; constant up to 850 °C) is carried out in autoclaves. The phase wollastonite Ca3Si309 without water is initiated by firing. Wollastonite serves as an additive and increases temperature resistance.

Low densities and high thermal insulation are characteristic properties. In general, lightweight calcium silicate boards do not have organic binders. The dehydration reactions during service determine the degree of firing shrinkage and, consequently, the service limit of the insulating material. The median pore size is approximately 0.5 µm. Calcium silicate boards are not suitable for service on the front side due to their sensitivity to thermal shock. However, where mineral wool, moler bricks and vermiculite cannot be used, calcium silicate is an ideal insulating material.
Calcium silicate insulating boards

These calcium silicate insulating boards differ from the above-mentioned product groups by having higher bulk densities and stabilities. They can be produced through filter pressing and Hatschek processes. The boards are strong, self-supporting, have good thermal insulating values and can be cut, drilled and milled with conventional woodworking tools.

The boards have a concrete matrix and are resistant to water and water vapour. They do not rot and mould and will not be attacked by vermin. In order to avoid metal corrosion through condensates, these boards are primarily used in dryer and plant constructions instead of steel sheet. Additionally, they can be used as top boards for sandwich elements with insulating cores and for application in the aluminium industry. Special coatings protect against increased humidity adoption and chemically aggressive media. (Promat product groep PROMAFOUR^® and PROMASSAL^®).

MICROPOROUS INSULATING MATERIALS

Microporous insulating materials show extremely low thermal conductivity values which are even below that of calm air. This is possible with pore sizes < 0.1 µm, which means that the hollow spaces are equal or lower than the size of the median stretch of gas molecules. This impairs heat transfer by convection and solid state conduction. The infrared permeability is further reduced by adding opacifiers.
Highly dispersive silicic acids, titanium dioxide and additives are the main components. The powder mixture is pressed to boards and shaped parts and then eventually processed. (Promat product group PROMALIGHT^®).

MINERAL FOARMS

Mineral foams are produced by a gas propellant process, for example from the main components of inorganic filling substances, water glass hardener and propellant. They are subsequently treated and finished by casting, extrusion or pressing. The chemical geopolymer formation is a polycondensation with separation of water.
The foams produced harden within a short time, which can be supported by heating. Depending upon the objective and propellant charge, bulk densities of 100 to 800 kg/m³ are obtained.

MINERAL WOOL MATERIALS

Glass wools are made out of glass melts with wide-ranging and different raw material compositions. Production is carried out by drawing, blowing, centrifugal and combined processes. The glass composition used depends on the specific application purpose (A-, C- and E-glasses).
In general, glass wool products are applied up to 500 °C, in special compositions up to 750 °C.
Mineral wools are made by remelting slags and/or rocks in cupola or electric furnaces. The next step is tofiberize the melt stream with blowing or centrifugal equipment. The application limit also depends on the chemical composition and is between 600 °C and 750 °C.
Further processing of the glass and mineral wool to mats, boards, cloth, paper, shaped parts and cords isperformed on separate production lines. On catalogue pages 46 - 47 the properties of PROMALAN^® mineral wool boards are listed. The most important applications are in the field of insulation against heat and sound in buildings, ships, aeroplanes, automobiles and other industrial applications
High temperature insulation glass wools were developed with the objective of reduced biological resistance in order to provide fibrous products for the high temperature field without classification.These products are earth alkali-silicates with similar chemical composition to that of glass and mineral wools. The application limit is strongly influenced by the thermal and chemical stress and is between 850 and 1200 °C for neutral atmospheres. Due to the short sintering range there is danger of over-heating. Aggressive media can dramatically shorten the life of the lining. (Promat products PROMAGLAF^®-HTI 1100 and –HTI 1250).