Silica
Finnfjord AS offer silica for sale at a competitive price. 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 silica is delivered in accordance with NS 3045:1992 and satisfies the requirements of ASTM C-1240/93. The company is certified in accordance with DS 478E:1996, including DS 478E/Ret.I:2000 by DANCERT, and is certified according to NS ISO 9001:2000 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. | ||