What is the structure and function of silicon powder?

Haosen, a manufacturer of fused silica powder, has learned that silica powder is also called silica fume, silica powder or ultrafine silica powder.

Micro silicon powder is a kind of ultra-fine silicon powder material, which is formed by the rapid oxidation and condensation of SiO2 and Si gas produced by metallurgical electric furnace at high temperature above 2000 ℃ and oxygen in air.

1. Micro silica powder:

The appearance of the powder is gray or gray, and the fire resistance is more than 1600 ℃. Bulk density: 200-250 kg / m3.

The chemical composition of micro silicon powder is shown in the table below

Chemical properties of micro silicon powder as refractory material

2. Fineness of micro silica powder

Its fineness and specific surface area are about 80-100 times of cement and 50-70 times of fly ash. More than 80% of the micro silicon powders are less than 1 μ m in fineness, with uniform particle size of 0.1-0.3 μ m and specific surface area of 20-28m2 / g.

3. Particle morphology and mineral phase structure:

The small spherical body can be used as lubrication for the materials mixed with micro silica powder. In the formation of micro silicon powder, amorphous spherical particles are formed due to the action of surface tension during the phase transformation, and the surface is relatively smooth. Some of them are clusters of multiple round particles. It is a kind of ash material with large specific surface area and high activity.

The micro silica fume can fill the pores between cement particles, and react with the hydration products naturally, and react with Magnesium Oxide, the basic material, to produce gels. In the cement-based concrete, mortar and refractory castable, the following functions can be achieved by adding appropriate amount of micro silica powder:

1. It can effectively prevent the reaction of alkali aggregate.

2. It is a necessary component of high strength concrete, and has been used in C150 concrete engineering.

3. The service life of concrete is obviously prolonged. Especially in the environment of chloride pollution, sulfate corrosion and high humidity, the durability of concrete can be improved by one or several times.

4. The floor ash of shotcrete and castable material is greatly reduced, and the thickness of single spray layer is increased.

5. It has the function of water conservation, preventing segregation, bleeding and greatly reducing the resistance of concrete pumping.

6. Improve the densification of castable refractory. When it is co-existence with Al2O3, it is easier to naturally develop mullite phase, which makes it have high temperature strength and high vibration resistance.

7. It has made great progress in the compression resistance, folding resistance, impermeability, anti-corrosion, impact resistance and wear-resistant function.

8. It has about 5 times the effect of cement, and can reduce cost and improve durability when applied in ordinary concrete and low cement castable.

If you want to know more about modified silica powder, you can consult Haosen, the manufacturer of fused silica powder.