The refractory material used in the early ladle slag line was directly combined magnesia-chrome bricks, Electrofusion combined with high-quality alkaline bricks such as magnesia-chrome bricks. After the MgO-C brick was successfully used in the converter, the MgO-C brick was also used in the refining ladle slag line, and good results were obtained. China and Japan generally use resin-bonded MgO-C bricks with a carbon content of 12% to 20%, while Europe mostly uses asphalt-bonded MgO-C bricks, and the carbon content is generally around 10%.
Japan Sumitomo Metal Corporation Kokura Steel Works used MgO content of 83% and C content of 14-17% MgO-C in VAD line section 1M1 instead of directly bonded magnesia-chrome bricks, and the life of the slag line was increased from 20 times to 30- 32 times. Japan Sendai Steel Plant LF refining ladle, using Mgo-C bricks instead of magnesia-chrome bricks, the life of the slag line has been increased from 20-25 times to 40 times, and good results have been achieved. Osaka Kiln Refractory Co., Ltd. studied the effects of carbon content and antioxidant types on the oxidation resistance, slag resistance and high temperature flexural strength of MgO-C bricks.
The mixture of fused magnesia and sintered magnesia, plus 15% phosphorus flake graphite and a small amount of magnesium aluminum alloy as antioxidants to makes MgO-C bricks, which have good use effects. When used in LF ladle slag line with a capacity of 100 tons, compared with MgO-C bricks with 18% C content without antioxidants, the damage rate is reduced by 20-30%, and the average erosion rate is 1.2-1.3mm/furnace.