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Silica

We offer both densed (500 - 700 Kg/m3) and undensed (200 - 350 Kg/m3) material. Due to a strong commitment to quality, the plant has strikt process control during the production process. Each lot leaving the plant has its own certicicate of analysis. The company is certified in accordance with EN 13263-1:2009 by Kontrollrådet, and is certified according to ISO 9001:2008 and ISO 14001:2004 by Det Norske Veritas.

The annual production of silica is 18.000 metric tons.

What is Silica?

The silica dust is initially a waste product from the production of FeSi. However, with today's cleaning technology, it has become a resource. New areas of application are constantly found, e.g. as an additive in concrete (increases the strength, prevents chlorine penetration and hence the corrotion of the reinforcing rods), and as a substitute for asbestos in wallboards. It is also used in cosmetics and contact lences. To strengthen and seal the concrete in the world's largest building, The Petronas Twin Towers in Kuala Lumpur, 4800 tons of silica was used, all delivered by Finnfjord  AS. Silica has been named the most important new concrete product of the nineties, even though it has been in commercial use since the end of the seventies.

Chemical Properties

Silica is an ultra fine powder made up of nearly completely round particles with an average sice of 0,15 micrometer. The particles are approximately 100 times smaller than cement granes, and fill the gaps that arise in ordinary concrete mixtures.

Advantages

  • improves longevity in general
  • increases resistance against sulfates and chlorides
  • contibutes to increased compressive, flexural and tensile strength
  • reduces permeability and water break-through
  • increases abrasion resistance
  • eliminates bleeding

Chemical properties of silica manufactured by Finnfjord

Element Limit Typical values
SiO2 >85 90-93
CaO <2,5 0,2-0,7
Na2O <1.8 0,2-0,6
K2O <2,5 1,0-1,3
Cl <0,3 0,05-0,15
SO3 <1,5 0,25-0,35
MgO <3,5 0,9-1,3
Fe2O3 <3,5 1,0-2,0
Al2O3 <2,2 0,4-0,9
Screen analysis, particles > 0,45µm <40 0,8-2,2
Loss of ignition, (LOI) <5 1,0-2,5
Free silicon     <0,4 <0,4 0,04-0,15
Specific surface, BET >15 20-24
Accelerated pozzolanic index >95 120-135
Carbon is normally 0-0,2 % lower than LOI.