Electric Arc Furnace

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Overview of Electric Arc Furnace

An electric arc furnace is a type of furnace used for the production of steel or other metals through the process of smelting. When gas discharge forms an arc, the energy is very concentrated, and the temperature of the arc zone is above 3000 ℃. It relies on the heat generated by an electric arc, which is created between the electrodes and the raw materials inside the furnace. The basic construction of an electric arc furnace consists of a refractory-lined vessel, usually cylindrical in shape, which serves as the melting chamber. The furnace is equipped with three graphite electrodes that are inserted through the roof of the furnace. These electrodes are connected to a powerful electric power supply.

An electric arc furnace is important equipment for the steel industry and metal production. It plays a crucial role in the melting and refining of metals, particularly steel. Electric arc furnaces offer several advantages such as flexibility in raw materials, lower capital investment, energy efficiency, and environmental benefits. Therefore, electric arc furnaces are vital in modern steelmaking, supporting sustainable practices and facilitating the production of high-quality steel.

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Basic Structure of Electric Arc Furnace

Based on electric arc form, the electric arc furnace can be divided into three-phase electric arc furnace, consumable electric arc furnace, single-phase electric arc furnace and resistance electric arc furnace. The furnace body of an electric arc steel-making furnace consists of a furnace cover, a furnace door, a tapping spout, and a furnace body. The furnace bottom and walls are constructed with alkaline or acidic refractory materials. The electric arc furnace uses electric energy as the heat source and can adjust the atmosphere inside the furnace, which is extremely beneficial for melting steel grades containing more easily oxidizable elements.

Refractory Materials for Electric Arc Furnace

AGRM Refractory is one of the most professional refractory material production enterprises in China, And our refractory products have property of high temperature resistance, good insulation, good chemical resistance, good abrasion resistance, etc. These properties ensure the efficient and reliable operation of the electric arc furnace, contributing to the production of molten metal for various industrial applications. An electric arc furnace consists of a furnace roof, furnace walls, furnace bottom, and a steel tapping spout. Different refractory materials are selected for different parts of it.

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Furnace roof

The top of electric arc furnaces is built with high alumina bricks, with an alumina content of 75% -85%. Compared with silicon bricks, high alumina bricks have characteristics of high fire resistance, good thermal shock resistance, and high compressive strength. High alumina bricks have become the main refractory material for electric arc furnace roof with a lifespan of about 2-3 times that of silicon brick furnace roof.

With the development of large ultra high power electric furnaces, high alumina bricks are gradually being replaced by alkaline bricks such as magnesium bricks and magnesium chromium bricks. It can also be hoisted by casting refractory prefabricated parts from merchants. Compared with ordinary masonry roof, it has the advantages of convenient construction, good integrity, strong resistance to arc radiation, and resistance to rapid cooling and heating.

Furnace Wall

The furnace wall is divided into general furnace walls, slag line areas, and hot spots near the arc. The furnace wall is mainly built with magnesium bricks, dolomite bricks, and square magnesium bricks. The slag line area and hot spots are the weak links of the furnace wall. The lifespan of the furnace wall mainly depends on the degree of damage to the hot spot area. Magnesium chromium bricks were often used for masonry in the early stages. Nowadays, magnesium carbon bricks with excellent high-temperature resistance and slag resistance are widely used for masonry. The service life has significantly improved, reaching over 300 heats.

Measures has taken to extend the service life of furnace wall. The inner surface of the furnace wall is sprayed with a layer of refractory coating to form a protective layer for slag hanging, which can effectively reduce the unit consumption of refractory materials.

Electric Arc Furnace

Furnace Bottom

Furnace bottom is the position that the furnace material and molten steel gather. The masonry or knotted lining in this area have the characteristics of uniform overall performance, tight masonry, good high-temperature performance, high strength, corrosion resistance, erosion resistance, good thermal shock resistance, and stable volume.

Good magnesia or fused magnesia should be selected for knotted lining, attention should be paid to the connection and interlocking of each layer, and the thickness and density of each layer should be consistent. Tar asphalt combined with magnesium bricks are used in the working layer, and the permanent lining should mostly be constructed by magnesium bricks. Due to severe slag erosion in slag line area, lining bricks that are similar to the hot spot area of the furnace wall are often used in this area, such as cast magnesium chromium bricks or combined with magnesium chromium bricks.

Tapping Spout

The bricks for the eccentric tapping spout are asphalt-impregnated fired magnesia bricks. The tube bricks are made of resin-bonded magnesia-carbon bricks with a carbon content of 15%. The end bricks are resin-bonded magnesia-carbon bricks with a carbon content of 10%-15%, and the ALO-C-SiC bricks with a resin-bonded carbon content of 15%. To ensure smooth steel tapping, coarse sand with olivine as the matrix is commonly used as the draining material.

AGRM Engineering Co., Ltd. provides customers with complete arc furnace technology, equipment, consumables such as graphite electrodes, spare parts, and exhaust gas treatment systems.

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