Silica fume, also known as microsilica, is a byproduct of the production of silicon metal or ferrosilicon alloys. Here is a general process of how silica fume is produced:

Raw Material Production

Silicon metal and alloys are produced in electric furnaces. The raw materials are quartz, coal, and woodchips. The smoke that results from furnace operation is collected and sold as silica fume, rather than being landfilled.

Furnace Operation

The raw materials are heated in an electric arc furnace that operates at temperatures up to 2000 degrees Celsius. This process results in the production of very pure silicon and a smoke or fume containing silicon dioxide (SiO2).

Fume Collection

The smoke is collected in bag houses, which are large fabric filters. The smoke or fume is extremely fine, with over 95% of the particles having a diameter less than 1 micron. This fine powder is silica fume.

Processing

The collected silica fume is then processed and packaged for distribution. It’s typically sold in a densified or undensified form, depending on the specific needs of the customer.

Silica fume is used in concrete and other construction materials because it improves the strength and durability of the material. It’s also used in refractory, ceramics, and other industrial applications.