Electrode heating is used in the heat preservation electric arc furnace, and the inner side of the furnace lining carries high-temperature slag liquid. When the high-temperature molten liquid comes out of the furnace, the temperature of the furnace wall will drop sharply, causing the furnace lining refractory to withstand the thermal shock of sudden cooling and sudden heating, and also to withstand the thermal shock of the molten slag. Oxidation and corrosion in contact with air during chemical erosion and liquid level drop, so the selection of refractory materials for furnace lining is very strict.

At present, the refractory materials used for electric arc furnace lining mainly include magnesia-chromium spinel bricks, high-alumina bricks, cold ramming paste, and other refractory materials, but in the production process, these three kinds of refractory materials cannot meet the requirements of use, and the service life does not exceed 3 months, resulting in the production line being unable to reach production capacity and unable to meet production requirements.

The inner lining of the thermal insulation electric arc furnace is built with magnesia-chromium spinel bricks, and the furnace bottom is built with high-alumina bricks. After 10 days of production, the furnace wall is completely corroded, and the furnace bottom is partially corroded.

The furnace bottom is built with pre-baked carbon bricks, the furnace wall is completely corroded and the furnace bottom is intact after 10 days of production and use.

High alumina bricks are used to build the furnace wall and pre-baked carbon bricks are used to build the furnace bottom. This scheme has been used for 40 days. The furnace wall is partially corroded and the furnace bottom is intact.

The furnace wall is built with cold ramming paste, and the furnace bottom is built with pre-baked carbon bricks. After 30 days of production and use, the furnace wall is completely corroded and the furnace bottom is intact.

Pre-baked carbon bricks are used to build the furnace wall and furnace bottom. After 90 days of production and use, the furnace wall is fully oxidized and the furnace bottom is intact.

The thermal slag of the holding electric arc furnace is an acidic slag. The furnace wall refractory is washed by acid slag, and its service life is very limited. Because the slag is not completely poured out to form a protective layer at the bottom of the furnace and the temperature is stable, it is feasible to use pre-baked carbon bricks to build the furnace bottom. Pre-baked carbon bricks have high refractoriness, excellent slag erosion resistance, excellent thermal conductivity, and a small expansion coefficient.

If silicon nitride refractory products are used, the corrosion resistance, wetting resistance of molten cryolite, oxidation resistance, wear resistance, high thermal conductivity, thermal shock resistance, and extremely low electrical conductivity are longer than those of other refractory materials. more than doubled. Silicon nitride has a good anti-slag corrosion effect. It is used as the inner lining of the lower furnace body of the electric furnace, and the structure of the contact with the air does not change after high-temperature impact, and its high-temperature resistance and oxidation resistance are excellent.

Since the price of silicon carbide nitride is too high, from the perspective of cost, silicon nitride bricks and pre-baked carbon bricks can be used together for the masonry of the thermal insulation electric furnace lining. The pre-baked carbon bricks are used for the masonry of the furnace bottom and the inner side of the furnace wall, and the nitrided silicon carbide bricks are used for the outer side of the furnace wall to be in direct contact with hot slag and air. This mixed-use makes the pre-baked carbon bricks, not in direct contact with the air, reduces the oxidation erosion of the pre-baked carbon bricks, and reduces the masonry cost, and the excellent performance of the nitrided silicon carbide bricks can ensure the service life of the insulation furnace lining.