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Manufacturers and Distributors of Vermiculite,
Insulating Materials
and selected Refractory Materials


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Olifantsfontein, 1666
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Manufacturers and distributors of Vermiculite, Insulating Materials and Selected Refractory Materials

Technical Data of a Typical Culite S


SiO2:                            47%

Al2O3:                         23%

Fe2O3:                         5,5%

TiO2:                           1,6%

CaO+MgO:                  19,2%

K2O+Na2O:                 3,0%

Physical Properties

Bulk density:                             0,56g/cm3 (@ ambient temperature)

Crushing strength:                    1,4 Mpa (@ ambient temperature)

Perm. Linear Change:             -1,0% @1000 °C

Spalling resistance:                 +30 cycles (0°C   - application                                                   temperature)

Maximum. Service.Temperature:         1100°C

Thermal conductivity:              0.13 W/mK (@250 °C)

Data are typical of day-to-day production, but are subject to normal statistical variation and should therefore not be considered as a binding specification. Where a property is critical, confirmation should be obtained from Insutech as to specification limits.

In addition to a great number of standard and special sizes Culite are also available in large slabs resulting in fewer mortar joints and significant labour savings.

Extensive lists/drawings of potential applications are available at your request.

An >40% alumina mortar is generally compatible with Culite S. If in doubt contact our technical staff for guidance.



The name vermiculite is derived from the Latin “Vermicular”, meaning “to breed worm”. Vermiculite is a naturally occurring mica mineral of laminar structure which has been heated in a furnace to create exfoliated granules with a very high surface area and inter-laminar air space (like a concertina). The inter-laminar air space provides a very high pore volume, typically 96% of total volume.  As with Perlite, pores may be filled with air or water, depending on size. The cation exchange properties of Vermiculite act as a nutrient buffer, releasing added nutrients to plants in a form they can easily assimilate.  In addition Vermiculite naturally contains magnesium, iron and potassium which are available for plant growth. Vermiculite has a neutral pH of between 6.0-7.0, is chemically and biologically stable and is free from pests, weeds and diseases.

Mineral wool products

These highly versatile refractory ceramic fibre products are lightweight, have low thermal conductivity, low heat storage and excellent resistance to thermal shock. They are available in a variety of densities, thicknesses and temperature capabilities.

Insulation fire-brick

High temperature insulating fire bricks based on a variety of raw materials and manufacturing processes offer superior insulating properties, minimising energy use, combined with the ability to withstand chemical attack and high heat conditions.

The Culite range of processed vermiculite products

Formulated to meet specific thermal and physical requirements Culite S is made from high purity South-African refractory vermiculite and other ceramic raw materials. Proven performance over the years reflecting the mastering of the technology of heat containment is testimony to the uniqueness of Culite S.

Its light weight and low thermal conductivity (k-value) allows for thinner furnace walls, improved energy conservation and lower operating costs. With a specific heat of 0,8 kJ/kgK lower heat storage versus denser brick means reduced fuel costs in particularly cyclically operating heating/firing equipment.

Culite H is a high strength vermiculite insulating brick. Its volume stability and thermal expansion levels make. Culite H is compatible with normal hot face firebricks. Uses include muffle kilns, pottery and enamelling furnaces, backing brick in boilers, annealing furnaces, soaking pits, linings for ducts and flues, etc.

Vermiculite board is made from a naturally occurring aluminium-magnesium silicate layer that has been already expanded with the application of heat. This expansion process is called exfoliation and the resulting material is used in bulk form or processed to boards by a press forming process. The board can be worked easily with wood working tools. It can be sawn, drilled and sanded.