Abstract: Dust containing high-temperature gas exhausted from an electric steelmaking furnace is directed through scrap preheaters, wherein scrap that is to be charged into said electric furnace is preheated. The absorption of some of the heat from the exhaust leaving the electric furnace by the scrap, therefore, decreases the amount of electric power required for melting the steel scrap and also shortens the time required for steelmaking. Exhaust gas after preheating of the scrap is contaminated with incidental malodorous materials, e.g., paint and oil fumes, and is directed through a gas scrubber followed by a wet-type electric precipitator to remove these contaminants before release of cleaned exhaust gas into the atmosphere. A flow of alkaline aqueous solution of a deodorant solvent in the gas scrubber removes malodorous substances from the exhaust gas, simultaneously causing a drop in the gas temperature to a predetermined controlled value while generating a constant supply of saturated water vapor.

Abstract: A hot gunning robot system moves a gunning nozzle along a vertical center line of the furnace and changes the swiveling angle of the gunning nozzle to perform mending of all interior side and bottom surfaces of the furnace. The system comprises a shifter transferring the nozzle carrier from a housing position to a mending position in the furnace. The shifter has parallelogram-links and an actuator which actuates the links to move the nozzle carrier in an upright constant orientation. A water feeding tube is fitted on a vertical feeding pipe to mix lining material powder with water to obtain a sludgy lining material introduced into the gunning nozzle smoothly by guide vanes provided in a cylindrical nozzle supporter. The nozzle carrier is partitioned into a driving chamber and an air chamber and both of chambers are air cooled. A driving system and bearing system for the vertical feeding pipe is protected from the heat of the furnace.

Abstract: Dust containing high-temperature gas exhausted from an electric steelmaking furnace is directed through scrap preheaters, wherein scrap that is to be charged into said electric furnace is preheated. The absorption of some of the heat from the exhaust leaving the electric furnace by the scrap, therefore, decreases the amount of electric power required for melting the steel scrap and also shortens the time required for steelmaking. Exhaust gas after preheating of the scrap is contaminated with incidental malodorous materials, e.g., paint and oil fumes, and is directed through a gas scrubber followed by a wet-type electric precipitator to remove these contaminants before release of cleaned exhaust gas into the atmosphere. A flow of alkaline aqueous solution of a deodorant solvent in the gas scrubber removes malodorous substances from the exhaust gas, simultaneously causing a drop in the gas temperature to a predetermined controlled value while generating a constant supply of saturated water vapor.