The main methods for preparing ferrosilicon powder include remelting, pulverization, and atomization.
The remelting process uses a normally operating ferrosilicon submerged arc furnace and a bottom-blown oxygen-blown ladle. During tapping, oxygen and compressed air are bottom-blown into the ladle at a ratio of 2.0–12 m³/h : 1.0–6 m³/h. Simultaneously, a special flux, prepared from quartz sand, quicklime, oxide scale, and fluorite in a weight ratio of 40–44:28–35:1–5:13–20, is added at a rate of 3 wt%–5 wt% of the molten iron. Then, ferrosilicon powder is added to the boiling melt at a rate of 5 wt%–10 wt% of the molten iron. This process improves the fluidity of the molten iron, prevents surface crusting, and offers advantages such as energy saving, pollution prevention, increased yield, and economic benefits.
The pulverization method requires controlling the material temperature to prevent the ferrosilicon alloy from oxidizing when pulverized to a certain particle size. The complete pulverization process uses air-cooling and water-cooling systems to control the material temperature at room temperature or low temperature, solving the problem of easy oxidation and achieving continuous production without fire, oxidation, or pollution. Due to the high hardness and specific gravity of ferrosilicon, it causes severe wear on equipment; therefore, the main and auxiliary equipment must be made of stainless steel, and the pipelines must be made of high-polymer wear-resistant materials or lined with wear-resistant materials.
Atomization is one of the industrial methods for producing ferrosilicon powder. It uses a high-pressure gas stream to atomize molten ferrosilicon alloy into powder. This method is suitable for producing various grades of ferrosilicon powder, such as 45% and 75%, and has been applied industrially. Optimizing process parameters can improve powder quality and reduce costs.
