Ferrosilicon is an important raw material for metallurgical casting industry. There are five main production methods of ferrosilicon:
One is the use of fine charge production of high purity ferrosilicate.The second is to produce high purity and low carbon ferrosilicate by means of blowing chlorine refining outside furnace.The third is to produce high purity and low alumina ferrosilicate by using the method of top blowing oxygen outside furnace.The fourth is to produce high purity and low carbon ferrosilicate by hot washing slag.Five is to use the method of fine charge production of low aluminum, low carbon ferro silicon.
Using the method of fine charge to produce high purity ferrosilica is mainly smelting and producing the raw materials of quartz stone, petroleum coke, wood block, charcoal and silicon steel sheet, in order to reduce the content of impurity elements in the products.Because there is a volatile raw material quality, the method of smelting production process to avoid into part of impurities, thus the impurity content in the product rate is restricted, the product quality is not high, low yield, and production furnace condition difficult to maintenance and operation of the oven is difficult, the production cost and energy consumption is larger, poor economic indicators.In addition, the production often produces leakage and the blowing chlorine graphite pipe breaks off and stops refining, which seriously pollutes the environment, endangers the health of workers, and corrodes the production equipment.Therefore, it is not the preferred method.It is also better to remove calcium, aluminum and carbon impurities in the products by the method of top oxygen blowing outside the furnace.However, in the process of use, the temperature of molten iron drops rapidly due to the intense churning and large splashing loss of molten iron, resulting in a large loss of sticky bale and iron, and the loss is between 12%-20% according to data statistics.The graphite pipe used for oxygen blowing is often broken, and the refining is stopped, the yield is low, and the economy is very uneconomical.The method of fine charge production of low aluminum, low carbon ferrosilicate is mainly through the fine reducing agent, such as blue carbon, gas coal coke and other raw materials for smelting production, in order to reduce the impurities in the product, mainly aluminum content of the purpose.Due to the large fluctuation of raw material composition, this method inevitably brings some impurities into the smelting process, so the reduction rate of impurities in the product is limited. The aluminum content can be reduced to 1.6% or 1.2% at most, and the carbon content can be reduced to 0.2%, which can only produce some brand products.
Therefore, the specific production method can be decided according to the actual demand, and the method of energy saving, environmental protection and high economic benefit should be chosen as far as possible.