lignosulfonates, microsilica, stpp exports from Russia

Microsilica is a mineral composed of ultrafine amorphous spheres of silicon dioxide (SiO2), produced during the manufacture of silicon or ferrosilicon. This tightly controlled electro-metallurgical process involves the reduction of high purity quartz in electric arc furnaces at temperatures of over 2000oC The microsilica is formed when SiO gas, given off as the quartz reduces, mixes with oxygen in the upper parts of the furnace.

Here the SiO is oxidised to SiO2 condensing into the pure spherical particles of microsilica forming the major part of the smoke or fume from the furnace. Hence the alternative names for the material – condensed silica fume or silica fume.

The average particle is 0.15 micron in diameter, meaning that each microsphere is 100 times finer than a cement grain. In a typical mix, with a 10% dosage of microsilica, there will be between 50 000 and 100 000 microsilica particles per grain of cement.

Microsilica is a pozzolana – a term derived from the ancient Italian town of Pozzuli, where volcanic ash was mixed with burnt lime to make cement. This means that it will react with the calcium hydroxide given off by the cement hydration and form more of the calcium silicate hydrate crystal structure that binds concrete together. Because the microsilica is typically over 90% SiO2, the reactive component, it is a very powerful pozzolana.

To promote microsilica in concrete is to promote high quality concrete technology and the benefits of advanced concrete materials: in terms of durable infrastructure, advanced concrete structures and sustainable high quality concrete construction.

Bridge construction, marine structures, parking structures, water supply and sewage facilities all benefit from the use of microsilica (silica fume). Likewise, the special properties of microsilica concrete give benefits in fresh concrete properties, so that rheology improvements gives benefits in terms of concrete pumping and stability of the concrete mix. Special concretes like high strength concrete, light weight concrete (LWC, LWAC), shotcrete and low permeability concretes are better made with microsilica.

Applications

• Concrete
• Cementitous Repair Products
• Concrete Tile & Panels
• FCB, Concrete Roofing & Wallboards
• Shotcrete
• Oil Well Grouting
• Polymers & Elastomers
• Repair Products
• Refactory & Ceramics