White silica fume refers to 99% undensified silica fume and silica fume containing zirconia. Currently, the white silica fume available from Henan Superior Abrasives is 99% undensified silica fume, SiO2 >94%, ZrO2 <2% of silica fume.
White silica fume has good fluidity enhancement characteristics, and it can be well dispersed under the action of dispersant. The fine particle size of silica fume can improve the particle distribution in refractory castables, fill the voids between large particles, increase the density of castables, reduce the void rate, and make the castables self-flowing with less water demand. It is currently used in large quantities in high strength concrete, refractory materials, insulation materials, chemical coatings, oil well cement and other fields.
White silica fume is an indeterminate micro powder with spherical structure, which has high purity, high whiteness, high activity, high thermal conductivity, high insulation and high weather resistance, etc. White silica fume can be widely used in concrete, refractory materials, wall materials, cement products, mortar, flooring, chemical industry and other important fields used in special projects.
White silica fume is relatively rare, mainly because the production of white silica fume raw materials, the production process requirements are very strict, especially to strictly control the temperature control at high temperatures after sublimation time. Therefore, this also makes the production of white silica fume is small. The refractory temperature of white silica fume is 1800 degrees, which is higher than ordinary silica fume, so it is more popular in the refractory industry. White silica fume can be applied in the ultra-fine filler which requires high whiteness, such as grout, caulk, patching agent and other products. At present, very few domestic ordinary production lines of silica fume can reach the process conditions for producing white silica fume. Therefore, the price of white silica fume is much higher than that of ordinary silica fume.
The characteristics of white silica fume
- High purity, high whiteness, adjustable and controllable particle size, uniform distribution.
- Good weather resistance, good chemical stability, except for hydrofluoric acid, strong alkali reaction, does not react with any other substances.
- High hardness and high sex of silica fume improve the scratch resistance of the coating film.
- Low dielectric constant and dielectric loss, is the ideal filling material for electronic and electrical products.
- Low oil absorption, low viscosity, good dispersibility and fluidity.
Applications of white silica fume
Application in refractory materials
It can fill the pores between the particles in the castable and reduce the water consumption of the castable. Because of the spherical structure of silica fume, the relative sliding friction between the particles is changed to rolling friction when filling the particles, which reduces the friction between the particles and leads to the reduction of viscosity and improvement of fluidity of the castable.
It is mainly used as self-flowing refractory castables, prefabricated parts, breathable bricks, ladle materials, high performance refractory castables and wet and dry injection materials. As well as high temperature wear-resistant materials and products, corundum and ceramic products, etc.
Application in mixed cement
Silica fume is often used together with cement and other binding agents, generally grinding silica fume with clinker to produce mixed cement containing about 6% silica fume. silica fume has high surface area, which provides nucleation sites for hydration products of calcium aluminate cement, which is conducive to the crystallization of hydration products and improves the cementing effect between castable particles, thus improving the strength of castable. Now it has been widely added silica fume system mixed cement or cement.
Application in fertilizer industry
Silica fume and waste materials such as waste bark produced by wood factories are processed to form mixed substances, which can enhance soil fertility and improve the effect of soil varieties. Mixed with potassium carbonate or potassium hydroxide can be made into slow-release agricultural fertilizer potassium silicate, which can make crop root development, inhibit pests and diseases, not easy to volatilize and lose, and can protect the soil.
