Conventional micro silica fume
When ferroalloys are smelting ferrosilicon and industrial silicon (silicon metal), a large amount of volatile SiO2 and Si gas is produced in the mineral-heated electric furnace, and the gas is discharged and rapidly oxidized and precipitated with air. It is a by-product of large industrial smelting, and the whole process needs to be recovered by dust removal and environmental protection equipment, and because of its light mass, it also needs to be encrypted by encryption equipment. The density can be increased to 600~680 kg/m³.
Its classification is mostly based on silica content, divided into five standards: SF85, SF92, SF94, SF96, SF99, and other indicators are mostly used in national standards GBT 27690-2011, GBT 21236-207.
The role of conventional micro silica fume
The physical role
The physical role, that is the role of particle filling. Silica fume particle size is one percent of the size of cement particles, just as sand fills in the gap between stones, cement fills in the gap between sand, silica fume particles can fill in the gap between cement particles, making the cement paste more dense, reducing the permeability of cement stone, improving the strength of cement stone, while increasing the compactness of the interface between cement stone and aggregate, and improving the bond strength of the interface between aggregate and cement stone.
Chemical effect
Chemical effect, silica fume is mainly composed of glassy silicon dioxide, which has high chemical reaction activity at room temperature. Silica fume can react with calcium hydroxide produced by cement hydration (i.e., volcanic ash reaction or secondary hydration reaction) to produce calcium silicate gel. The structure of calcium hydroxide produced by cement hydration is loose and porous, which is detrimental to the strength, permeability and chemical resistance of the concrete.
Ultrafine micro silica fume
When ferroalloys are smelted with ferrosilicon and industrial silicon (silicon metal), a large amount of highly volatile SiO2 and Si gas is produced in the mineral-heated electric furnace, and the gas is discharged and rapidly oxidized and precipitated with air.
which has the following significant effects.
The Role of Ultra-fine micro silica fume
- Again improve the strength of concrete.
- Increase the meltability of the microsilica powder.
- Reduces the density of the micro silica fume.
- Reduces viscosity and facilitates transport.
Ultra-fine micro silica fume VS conventional micro silica fume
Micro silica fume is produced in ferroalloys during the smelting of ferrosilicon and industrial silicon (silicon metal), and a large amount of highly volatile SiO2 and Si gas is produced in the mineral-heated electric furnace. However, the dense and high quality of the microsilicon powder collected by the dust removal equipment often causes dust pollution, so nearly all microsilicon powder companies are forced to encrypt the microsilicon powder. The encryption process will make the role of micro silica fume in the main body is greatly reduced. For example, the fineness of micronized silica powder on the market is about 300 mesh. The micro silica fume is lighter and more viscous, so it cannot be decrypted at the construction site after encryption, nor can it be ground finely again.
The fineness of Henan Superior Abrasives‘s ultrafine micro silica fume can be controlled from 325 mesh to 4000 mesh, and the fineness can be adjusted according to the customer’s specifications.
The new ultrafine micro silica fume takes environmental protection into consideration at the early stage of production, making the powder more environmentally friendly while refining the product. Ultra-fine micro silica fume can fill the gaps that cannot be filled by traditional micro silica fume, and make the strength of concrete improve again, and again improve the strength and durability of concrete, high compression, bending, seepage resistance, anti-corrosion, impact resistance and wear resistance. And the density of ultra-fine micro silica fume is much lower than the traditional micro silica fume, and consumes part of the viscosity, making the ultra-fine micro silica fume better delivery.
The continuous upgrading of smelters has led to continuous changes in traditional micro silica fumes, some of which are unable to melt water well, making their innate advantages and usefulness greatly reduced, and even unusable in some fields. Ultra-fine micro silica fumes also solve this problem, making better water melting. The sieve allowance of conventional microsilica powders is usually 3%-10%. The sieve allowance of ultra-fine micro silica fume is 0. And the ultra-fine micro silica fume increases the fluidity and compatibility of micro silica fume.
The Superfine micro silica fume produced by our company is finely processed by ultrafine vertical mill, and its particles are in the shape of round spheres, with fineness of D50 reaching 2000-3000 mesh and D90 reaching 800-1000 mesh. This high-end microsilica powder provides a guarantee and support for high-tech applications in various fields, Superfine micro silica fume is also available with a silica content of 85-99.
