Document Type and Number:
Japanese Patent JPS5227084
Kind Code:
B1
Abstract:
1,144,070. Rotary hearths. MIDLANDROSS CORP. 18 July, 1966 [19 July, 1965], No. 32174/66. Heading F4B. An annular rotary hearth furnace for heattreating materials containing iron oxide is formed with a two-inch surface layer containing wustite as a major constituent. Below the wustite surface layer the hearth comprising a two-inch layer of 95% magnesium oxide castable refractory, a four-inch layer of hard clay castable refractory, and a six-inch layer of insulating castable fireclay refractory. The surface layer is formed by supplying a pelletized magnetite concentrate with 4% of silica and 5% of coal on to the hearth and reacting this as it rotates in a reducing furnace atmosphere. Vitrified wustite is formed at temperatures between 2100‹ and 2500‹ F. Excess wustite formation during operation of the furnace, may be milled off by a milling screw, particularly if the surface layer is heated prior to milling. The addition of silica, reduces the temperature of formation of vitrified wustite, whilst a dolomite or magnesia addition increases it.
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Application Number:
JP4692366A
Publication Date:
July 18, 1977
Filing Date:
July 19, 1966
Export Citation:
International Classes:
C22B1/26; C04B35/01; C21B13/00; C21B13/08; C21B13/10; F27B21/00; (IPC1-7): C22B1/26