Industrial Silicon Requirements For Silica Raw Materials

The cleanliness of silica

The higher the content of impurities, the furnace surface obviously sticky, the furnace air permeability is not good, the temperature of the surface rises and redness, the heat loss is large, thus increasing the power consumption; Therefore, the selection and washing of silica is one of the main measures to reduce the impurities brought into the silica, energy saving and consumption.

It is understood that for the production of superior industrial silicon silica, its oxide impurity content should reach Fe2O3 less than 0.15%, Al2O3 less than 0.20%, CaO less than 0.15%. If the production of super high quality industrial silicon, the control of oxide impurities is more strict, Fe2O3 is less than 0.1%, Al2O3 is less than 0.15%, CaO is less than 0.10%, and there are strict requirements for boron (B) phosphorus (P) in silica.

Thermal stability and knock resistance of silica

The silica added to the electric furnace should have sufficient thermal stability and good blast resistance. Otherwise, it will break quickly because of heat and the surface quickly spalling, resulting in poor permeability of the electric furnace, bonding of the upper charge of the electric furnace, increasing heat loss and power consumption, so this phenomenon should be considered when choosing.

The granularity of silica

If the particle size is too small, the permeability of the charge is poor. If the particle size is too large, the unreacted silica will sink into the bottom of the furnace or enter the silicon solution, resulting in an increase in the amount of slag and the power consumption will increase. Therefore, it is necessary to control the particle size range of silica within 50-120mm.