Production process of fused alumina brick and issues needing attention
Date:2019-12-19 15:41 From:Zhengzhou Sunrise Refractory Author:admin
How is fused alumina produced?
The production process of electrofusion is a reduction melting process. The purpose is to remove Fe2O3, TiO2, CaO, etc. from the impurity components through reduction to obtain complete crystals and dense structure. Carbonaceous substances (anthracite, coke, petroleum coke, etc.) are used as reducing agents during melting. The reaction principle is as follows:
SiO2 + 2C → Si + 2CO
Fe2O3 (FeO) + 3C → 2Fe + 3CO
Si + Fe → Si-Fe alloy
TiO2 + 2C → Ti + 2CO
2TiO2 + C → Ti2O3 + CO
TiO2 + C → TiO + CO
CaO- → CaO.6Al2O3, CaO.Al2O3.2SiO2
The reduced iron, silicon, and titanium are incorporated into the ferrosilicon alloy for the second time. The density of the ferrosilicon alloy is greater than that of alumina, sinking into the bottom of the furnace, and separating it from the Al2O3 melt.
During the reduction and melting process, part of the TiO2 is reduced to some titanium-containing minerals. These minerals will expand violently when cooled to 400 ~ 600 "C and cause cracks in the frit. This is due to the formation of rutile by the oxide. Therefore, you can At the end of the smelting process, oxides (rolled steel) are added to oxidize the titanium and its compounds that have been reduced to eliminate this effect.
What should be paid attention to when producing fused alumina?
In the production of fused alumina, the operation control must be strict, so that the raw materials in the furnace are fully melted and reduced. The melt slowly rises, the material surface sinks evenly and normally, and the ferrosilicon alloy fully sinks, and the generated gas can be evenly discharged, so as to avoid splashing and sudden sinking of the material layer or severe sintering, which will affect the normal melting.
The main cause of splashing during the production of electric corundum is caused by the poor permeability of the production gas and the charge. Therefore, the added charge must be fully dried and roasted and dehydrated. The particle size of the charge is generally 10 ~ 14.