Ferosilicon is afraid of moisture, so pay attention to moisture proof and waterproof in transportation and storage.But sometimes due to the storage of water or air humidity is too large, while the content of aluminum, calcium and phosphorus impurities is high, after a certain period of time, it will produce the phenomenon of pulverization, and then the release of stink, toxic phosphine (PH3) and hydrogen (ASH3) gas, and even serious combustion phenomenon may occur.
Aluminum, phosphorus and calcium in ferrosilicon improper content, will contribute to ferrosilicon pulverization.When the content of aluminum and phosphorus increases to a certain value at the same time, the ferrosilicate is easy to pulverize in the air with higher humidity.Some data pointed out that the phosphorus content of ferrosilicon is less than 0.04%, aluminum content is less than 3%, not easy to produce the phenomenon of pulverization.
Some units have been on the silicon content of ferrosilicon on ferrosilicon pulverization phenomenon has been observed and studied.It is thought that the silicon content in ferrosilicon is low (mostly waste) and it is easy to be pulverized.The reason may be that FeSi, FeSi2 and other silicon and iron compounds in ferrosilicate decrease in temperature and expand in volume, resulting in ferrosilicate powder.The main cause of ferrosilicate powder is the formation of alumina hydroxide and gas when ferrosilicate containing aluminum meets water.
The cooling rate after casting also has an effect on ferrosilicate powdering.The cooling speed of ferrosilicate is fast, the segregation degree of silicon is small, and it is not easy to pulverize.The cooling speed is slow, the segregation degree of silicon is large, it is easy to produce pulverization.Similarly, the thickness of ferrosilicate ingot is thick, easy to produce pulverization, thinner is not easy to produce pulverization.
In order to prevent ferrosilicate pulverization, the following three points should be noted:
1. The thickness of ferrosilicon ingot is not easy to be too thick, in order to reduce the segregation degree of ferrosilicon.
2. Strictly control the silicon content of ferrosilicon, not too low.Control ferrosilicon aluminum, phosphorus and calcium content, so to use better raw materials, especially can not use high ash coke, in order to reduce aluminum, phosphorus content, in order to reduce the calcium content of ferrosilicon, smelting should be as far as possible to reduce the addition of lime.
3.Ferrosilicate should be stored in the warehouse, strictly protected from rain.