Although silica fume is a by-product of large industrial smelting, it plays a very important role in many industrial fields, so few people in the relevant industry fields do not know it, silica fume is not only alias a lot, it also has many types, come to know what is the classification of silica fume, right?

Silica fume by color

The color of silica fume is roughly divided into three kinds: light color, white, black. There are many factors that lead to the difference in the color of silica fume, smelting formula and different raw materials, the color of the produced silica fume is also different, but the content of silicon generally does not change much, mainly because of the difference in the content of other substances, caused by the color change.

Light-colored silica fume

Light-colored silica fume is rare in silica fume and belongs to a rare species. Its generation process requires higher temperatures, and the firing process in the electric arc furnace is also more demanding, and must ensure that the coke as well as the impurity composition of quartz is very low, and the smelting process should pay attention to the treatment of waste discharge, which requires the separation of silica fume generation to obtain.

The smooth and rounded surface of fine beads of silica produced by coagulation at high temperatures. So the color is light close to white. High silica content of light-colored micro silica powder used in concrete has increased concrete denseness increase strength. Good fluidity and low water requirement. Good adaptability with water reducing agent. Will not deepen the color of concrete.

White silica fume

White silica fume (powder) is a very rare silica fume. It has very strict requirements for the production of raw materials, production process and other aspects. Its yield is very small, and it can be applied in the ultra-fine filler which requires high whiteness, such as grout, caulk, patching agent and other products. The refractory temperature of white micro silica powder is 1800 degrees, which is higher than ordinary micro silica powder, so it is more popular in the refractory industry. The production of white silica fume (powder) requires a process that is mainly in the control of the time of temperature maintenance after high temperature sublimation. At present, very few domestic ordinary production lines of silica fume can meet the process conditions for producing white silica fume. Therefore, the price of white silica fume is much higher than the price of ordinary silica fume.

Black silica fume

Black silica fume contains high purity silica and has finer particle size, so it is more active and suitable for high temperature and high strength concrete. It is widely loved by users. Black silica fume can also be used in ordinary concrete to play a significant increase in strength and significantly increase the durability of the function of reducing costs.

In the use of oil cementing, black silica fume has a more special role. In the process of oil extraction, the temperature of superheated steam injected into the formation is up to 300 degrees or more. At such high temperatures, the strength of ordinary silicate cement decreases dramatically. Therefore, adding silica fume to cement can effectively improve the thermal stability of cement, and because black silica fume contains a large amount of high-purity silica, it is more suitable for application under high temperature conditions.

Silica fume classification according to morphology

Silica fume can be divided into powdered silica fume and granular silica fume according to its morphology.

Powder silica fume

Generally speaking, powdered silica fume is not processed by encryption equipment; granular silica fume is produced by encryption equipment. There is a big difference between the two in terms of stacking density, but there is little difference in chemical composition.

Granular silica fume

Granular silica fume is more stable in physical form, its dust is united into balls, not easy to be lifted, and performs better in constructability. Some countries have very strict requirements for environmental protection, so the use of granular silica fume can reduce the pollution to the environment during construction. In terms of transportation efficiency and cost control, granular silica fume also has its own advantages.

At present, silica fume is used in large quantities in the construction industry and refractory industry, with the construction industry, refractory industry process modification and the nature of silica fume itself. After the encryption process, the granular silica fume has been widely recognized.

Today we have discussed the classification of micro silica powder according to color and form, but in fact micro silica powder can also be classified according to many other properties, such as: silica content, density, particle size, etc. For more information about the classification of micro silica powder, please visit: https://hsamaterial.com/blog/micro-silica-fume-grades-and-their-uses.html