| 摘要 |
PROBLEM TO BE SOLVED: To provide a raw-material projection device which projects a raw material such as lime into molten pig iron to adjust components of the molten pig iron in a hot-metal ladle in a preliminarily treatment of the molten pig iron. SOLUTION: This projection device includes: a raw-material projection mechanism; a dust-collecting hood 4 serving as a lid of the hot-metal ladle 1; a lifting and lowering device 8 for the dust-collecting hood 4; a lance 3 which penetrates the dust-collecting hood and projects the raw material into the molten pig iron therethrough; and a waste-gas exhaust mechanism which is connected to the dust-collecting hood. The dust-collecting hood seals the hot-metal ladle with the lifting and lowering device when the raw-material projection mechanism projects the raw material into the molten pig iron. The waste-gas exhaust mechanism includes a dust collector, a dust-collecting duct 6, and a gas-exhaust adjustment valve 10 between the dust-collecting duct and the dust-collecting hood. The raw-material projection mechanism includes a raw-material delivery device, a pipe line d which connects the raw-material delivery device with the lance, and an adjusting valve 11 on the way of the pipe line. The degree of opening of the gas-exhaust adjustment valve is adjusted so as to minimize the amount of the waste gas to be exhausted on the basis of the inner pressure of the hood, the pressure in the dust-collecting side and the dead weight of the gas-exhaust adjustment valve. The degree of opening of the adjusting valve is adjusted so as to maximize the yield of the raw material in the adjusted degree of opening of the gas-exhaust adjustment valve. COPYRIGHT: (C)2011,JPO&INPIT
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