Explain Submerged Arc Furnace's Furnace Refractory Requirements and Selection
The submerged arc furnace is used for the reduction and smelting of metal oxide ore, so it is also called the submerged arc reduction electric furnace.
When the submerged arc furnace is used to produce ferroalloy, it is called a ferroalloy furnace: when it is used to produce calcium carbide, it is called a calcium carbide furnace: when it is used to produce yellow phosphorus, it is called a yellow phosphorus furnace: when it is used to produce matte, it is called matte furnace: it is used for ferroalloy refining It is called submerged thermal refining furnace: when it is used to melt the pre-reduced charge and separate the metal from the slag, it is called a melting furnace.
For the submerged arc furnace, the refractory masonry is the furnace lining. Because the molten pool of the submerged arc furnace not only withstands strong high-temperature action but also is eroded and mechanically scoured by the charge, high-temperature furnace gas, molten iron,, and high-temperature slag, specific refractory materials must be selected.
Requirements for refractory materials: high refractoriness, large changes in shape and volume at high temperature, high-temperature strength, good slag resistance, and good chemical stability at high temperature, various refractory materials should keep their appearance clean and complete in structure, the corner corrugation has no defects, and the surface has no cracks
In the masonry of the submerged arc furnace, the refractory materials for the submerged arc furnace are mainly made of refractory bricks, and the refractory castables are the auxiliary masonry configuration. The choice of material is as follows:
1. Carbon brick
Carbon brick is a kind of carbon material. It is made with crushed coke and anthracite. Its specifications are: section 400mm×400mm (the allowable error is ±30mm), length is 800~1600mm (the allowable error is ±5mm);
The advantages of carbon bricks are high refractoriness, strong thermal shock resistance, high compressive strength; good stability, especially volume stability, and good slag resistance. However, it is easy to be oxidized at high temperatures, and the oxidation speed will increase with the increase in temperature.
Therefore, the carbon material cannot come into contact with gases such as air and water vapor at high temperatures. Carbon materials have high thermal conductivity and poor thermal insulation performance. In the submerged arc furnace, carbon bricks can be used as the lining material for all varieties that are not afraid of carburizing in smelting, and self-baking carbon bricks are used in the submerged arc furnace.
2. Magnesia brick for submerged arc furnace
The main component of magnesia brick is magnesia, its refractoriness is above 2273K, and its alkali resistance is very strong; but its softening point under load is low, and its thermal shock resistance is poor. Most of the refining furnaces are smelted in an alkaline environment, and alkaline refractory materials that resist alkaline corrosion should be selected, such as magnesia bricks as linings.
3. Clay bricks
Clay bricks are weakly acidic refractory materials, which can resist the erosion of acid slag, and refractory clay bricks cannot be used at high temperatures.
In summary, the selection of refractory materials for submerged arc furnaces should be professionally configured according to the actual smelting environment and smelting raw materials. High-alumina bricks can also be used to replace clay bricks in the molten pool of submerged arc furnaces. In terms of performance, high-alumina bricks have more advantages. Among the unshaped refractories, cold ramming pastes and high-alumina castables are the main ones.