Processing materials

    Biogenic silica.

    The term ‘biogenic silica‘ (also known as rice husk ash) indicates the product's source. Biogenic silica is a natural, renewable raw material. Rice husks are used in modern biomass power plants as a quality-controlled source of energy. Hereby, the raw material is burned in a CO2-neutral manner. This means that during combustion, no more CO2 is released than the rice plant absorbed from the atmosphere during its growth. An aspect with increasing importance for raw materials in future.

    Thermal conductivity of NERMAT®
    Biogenic silica features a high chemical purity and consists of 94...96 % SiO2. This explains the high melting point of about 1.650 °C. During production, the volatile constituents are incinerated, but without destroying the microporous structure of the SiO2.

    It is this structure that leads to the extremely low thermal conductivity as well as the low bulk weight of biogenic silica.
    Depending on the manufacturing process, various bulk weights of our products are possible.

    NERMAT® AF-V ~ 160 kg/m3
    NERMAT® AF ~ 200 kg/m3
    NERMAT® BF ~ 190-350 kg/m3

    Thanks to its special properties, biogenic silica is the ideal and therefore most widely used insulating material in the steel industry.
    For more than 30 years NERMAT® AF has been the classical thermal insulating cover material for continuous casting tundishes and casting ladles, and has set high standards in quality and economy worldwide.
    SILIMAT® G is the low-carbon version. In particular, this white biogenic silica is used for the production of ULC steel with carbon contents of less than 25 ppm. But NERMAT® AF and SILIMAT® G are also used in ingot casting to insulate the ingot head and as raw materials.
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