How to smelt metallic silicon？

How to smelt silicon metal?

Silicon Metal

Metallic silicon, also known as industrial silicon or crystalline silicon, is usually produced by reducing silicon dioxide with carbon in an electric furnace. Metallic silicon is a product smelted from quartz and coke in an electric furnace. The main component silicon content is about 98% (in recent years, 99.99% Si content is also included in metallic silicon), and the remaining impurities are iron and aluminum. , calcium, etc. Its main uses are as additives for non-iron-based alloys and starting materials for the production of semiconductor silicon and organic silicon.

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In our country, metallic silicon is usually classified according to the content of its three main impurities: iron, aluminum, and calcium. According to the percentage content of iron, aluminum, and calcium in metallic silicon, metallic silicon can be divided into different grades such as 553, 441, 411, 421, 3303, 3305, 2202, 2502, 1501, and 1101. (About the source of metal silicon numbers: The 1st and 2nd codes represent the percentage content of iron and aluminum, and the 3rd and 4th digits represent the calcium content. For example, 553 represents the iron, aluminum, and calcium content of 5% and 5%. , 3%; 3303 represents that the content of iron, aluminum and calcium is 3%, 3%, 0.3%)

Metal silicon is produced using the carbothermal method, which is a method of smelting silica and carbonaceous reducing agents in a submerged arc furnace. The purity of the silicon produced in this way is 97% to 98%, and this kind of silicon can generally be used for metallurgical purposes. 

If you want to obtain higher-grade silicon, you need to refine it to remove impurities to obtain metallic silicon with a purity of 99.7% to 99.8%.