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method for the reduction of iron ore in a blast furnace.
method for the reduction of iron ore in a blast furnace.
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机译：高炉中还原铁矿石的方法。
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1334174 Blast furnace operation NIPPON KOKAN K K and W WENZEL 9 June 1971 [20 June 1970] 19545/71 Heading C7D [Also in Division F4] An auxiliary reducing gas is introduced into the furnace above the melting zone the blowing rates of gas and of blast air each being varied cyclically in opposition so that a substantially constant flow of top gas results, while the feed rates and temperatures may be such that a mixed gas temperature of about 1000‹ C is maintained after mixing of the two streams inthe furnace. The blowing periods are preferably so controlled that during maximum gas injection ore is reduced to sponge down to the level where the reducing and hearth gases meet, the sponge then being melted during the period of maximum air blast; during the latter period the top gas may be used for heating the blast, while during injection of reducing gas the latter may be obtained from the top gas. Alternatively the reducing gas may be obtained from an independent source, such as a fluid or solid fossil fuel, possibly by reacting natural gas or petroleum with an oxygen-containing gas in a regenerator. The temperature and nitrogen content of the air blast may be higher and lower respectively during the period of minimum flow than during maximum. In a particular form of apparatus described, blast air from heater 7 is introduced through tuyeres 4, while reducing gas from heater 18 is introduced at 22 above the melting zone 6. Top gas for heating is drawn off through line 5a and supplied to gas scrubber 11, and heaters 18, 7 while reducing gas is taken off through line 5b and passed, if necessary with supplementary gas from line 16, through scrubber 11 before being reheated and returned to the furnace. To ensure adequate penetration of the air blast into the burden it may be blown at constant velocity independently of flow rate.
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