The iron in ferrosilicon comes from the steel shavings in the charge. According to the quality requirements of ferrosilicon, only ordinary carbon steel shavings are allowed to be used in smelting, and alloy steel shavings are not allowed, such as stainless steel, high chromium content, high manganese steel, etc. Therefore, if alloy steel shavings are used to smelt ferrosilicon, it will result in waste products. Pig iron filings cannot be used either because of its high phosphorus content. Ferrosilicon smelting should not use non-ferrous metal shavings such as copper and aluminum. Therefore, in order to improve the quality of ferrosilicon, only ordinary carbon steel shavings are allowed to be used in smelting.
Steel shavings with a lot of rust cannot be used because there are many impurities, and the iron content is not easy to control during smelting. At the same time, steel shavings with a lot of rust have poor strength and a lot of powder. Therefore, it is stipulated that the iron content of the steel shavings used should be greater than 95%, and the surface should be clean without many impurities.
The length of the steel shavings should not be too long to prevent uneven mixing and blockage of the feeding pipe. Too long steel shavings will also cause uneven charging of the charge and affect the unbalanced three-phase load. For this reason, it is advisable to stipulate that the length of steel chips should not exceed 100 mm.
