Electric Arc Furnace Refractory

Selection of Refractory Materials For Electric Arc Furnace

Design of refractory materials for furnace wall and furnace bottom of electric arc furnace.

The working conditions of the furnace wall and furnace bottom are roughly the same as those of the furnace cover. 

They are susceptible to the high temperature radiation of the arc. They work under extremely high temperature conditions and are often subjected to quenching.

More serious than the furnace cover is that the furnace wall and furnace bottom are directly contacted with molten steel and slag, and are eroded by molten steel and slag, and are also impacted by the charge when charging.

Therefore, it's very important to choose high-quality refractory materials, especially the parts in contact with the slag and the parts close to the arc hot spot have higher requirements. 

The Commonly Used Refractory Materials Are As Follows:

① Magnesia

Magnesia is one of the main materials for building the lining of alkaline electric arc furnaces. It's used to knot the bottom and slope of the furnace, and can also be used to make magnesia bricks.

At the same time, it is the main material for furnace repair.

Magnesia is calcined from natural magnesite at a temperature of 1650°C.

The refractoriness of magnesia can reach above 2000 ℃, and it has better ability to resist the erosion of basic slag.

However, its thermal stability is poor and its thermal conductivity is large. The main component of magnesia is magnesium oxide> 85%, and also contains a small amount of impurities.

② Dolomite

Dolomite is also one of the main materials for the lining of alkaline electric arc furnaces. 

It's used as furnace wall and furnace repair material, and can also be made into dolomite bricks.

The refractoriness of dolomite is also above 2000°C, it can resist the erosion of alkaline slag, and its thermal stability is better than that of magnesia, but dolomite is easy to absorb water and pulverize.

Therefore, the time from firing to use of dolomite should be shortened as much as possible.

③ Quartz Sand

Quartz sand is one of the main materials for the lining of acid electric arc furnaces.

Pure quartz sand is a crystal transparent body. It is white when it contains a small amount of florets. The more florets are, the darker it becomes. 

The quartz sand used in electric arc furnaces is mostly white.

④ Various Refractory Masonry

Clay is mainly used as a refractory material for the furnace wall and furnace bottom of the electric arc furnace, so the refractoriness and the softening temperature under load are low, and it is used as an insulating brick inside, which is built near the furnace shell.

In the clay bricks, magnesia bricks and other alkaline bricks are built again.

Due to the lack of raw materials, magnesia-alumina bricks are more expensive and less used. 

Silica bricks are used in acid electric arc furnaces.

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