Indexed on: 01 Mar '61Published on: 01 Mar '61Published in: Refractories and Industrial Ceramics
In addition to magnesite-chrome concretes with periclase cement base, they can also be manufactured using a periclase-spinel cement. These concretes show less initial strength, but they soften to a lesser degree over the range 400 to 1000–1200°, hence after heating their strength is not lower than concrete with a periclase-cement base.The least softening of magnesite-chrome concretes over the given temperature range is shown by those with the addition of magnesium sulphate solution and soluble glass; as the modulus of the soluble glass is reduced, the compressive strength of the concretes under air-dry conditions and during heating increases. To obtain strong concretes, the soluble glass modulus must come within 1,8–2,2.In pneumatic tamping the strength of magnesite-chrome concretes is much greater than in vibration methods.In the spouts of electric steel-smelting and open-hearth furnaces, magnesite-chrome concrete showed a high degree of resistance, and its use for this purpose should be widely recommended.In the walls of an electric steel smelting furnace, the magnesite-chrome concrete was not inferior in strength to magnesite brick. The concrete containing magnesium sulphate was particularly satisfactory in this respect.The positive results of the test show the advisability of using concretes with a magnesium sulphate bond in the walls of electric furnaces with a view to replacing rammed linings made with a tar and pitch bond.The use of concrete for lining arresters in vacuum steel casting ensures satisfactory steel casting and has no effect on the quality of the metal.