Electric Furnace Magnesia-Carbon Bricks
Electric furnace magnesia-carbon bricks are refractory products manufactured primarily from fused magnesia and flaky graphite. They are produced by resin-bonded pressing and heat treatment. Since their industrial introduction in 1970, these bricks have been widely used in hot spots and slag line areas of electric furnace walls, offering high refractoriness, excellent thermal shock resistance, and superior slag corrosion resistance. Their carbon content ranges from 10% to 30%, which is higher than the 10%–20% typically found in converter magnesia-carbon bricks.
In the United States, Europe, and Japan, these bricks have largely replaced fused magnesia-chrome, re-bonded magnesia-chrome, and straight-bonded magnesia-chrome bricks at hot spots in electric furnace walls. Typically, a variety of magnesia-carbon bricks are employed in electric furnaces, including those with varying carbon content (or different C/MgO ratios), different types of carbon, different magnesia grades, and different binder systems.
The most notable difference between magnesia-carbon bricks for electric furnaces and those for converters lies in their fixed carbon content: electric furnace bricks contain 10%–30%, compared to 10%–20% for converter bricks. Consequently, the production of electric furnace magnesia-carbon bricks calls for a higher proportion of flaky graphite. Other manufacturing steps remain essentially the same as those for converter bricks.
In high-power and ultra-high-power water-cooled electric furnaces, these bricks are particularly effective in areas subject to severe wear, such as hot spots and slag lines. In such applications, their service life can exceed 300 heats. Magnesia-carbon bricks are now also being used in the bottoms of electric furnaces.
