DEVELOPMENT OF HIGH EFFICIENT SYNTHESIS PROCESS OF IRON CARBIDES IN A FLUIDIZED BED

碳化铁有望作为替代废铁的新铁源用于炼钢，特别是电弧炉炼钢。本研究的目的是在沸腾床中生产高质量的碳化铁，并检测其在钢水中的熔化行为，以明确它们在不久的将来用于炼钢的可行性。在1995年，新建了一个内径为62 mm的沸腾床来生产碳化铁(Fe3C，6.7质量%，直径：0.1-1 mm)。根据一种新的工艺概念，在8000℃左右用我们指定的气体与铁矿石反应进行了初步的生产试验，在1996年和1997年，用同样的方法在沸腾床上成功地生产出了高质量的碳化铁。熔炼试验是在50 kg感应电炉中用喷枪将碳化铁用Ar气体吹向钢水表面。通过测量熔体和出口气体中的温度和物种含量的变化来评估质量平衡和热平衡。碳化物被证明溶解在熔体中没有任何问题。碳化度越高，熔化热越低。此外，熔体中氮的去除也得到了预期的确认。

Iron carbide is expected to be utilized as a new iron source alternative to iron scrap for steelmaking, especially using an electric arc furnace. Objectives of this research are to produce high quality iron carbides in a fluidized bed and examine their melting behavior injected into molten steel, in order to make clear a feasibility for them to be available for steelmaking in the near future. The following results were derived during three years.At I 995, a fluidized bed (62mm inner dia) was newly constructed to produce iron carbides (Fe3C, 6.7mass%, diameter : 0.1-1 mm). Some preliminary production tests were carried out by reacting iron ores with our specified gas around 8000C on the basis of a new process concept.At 1996 and 1997, much high quality iron carbide was successfully produced by the same manner in the fluidized bed. The melting tests were performed by blowing the iron carbide with Ar gas to the surface of molten steel through a lance in a 50kg induction furnace. Mass and heat balances were evaluated by measuring the variation of temperature and contents of species in melt and exit gas. The carbides were proved to be dissolved into melt without any problems. Their melting heats tended to decrease with higher carbidization. Also, nitrogen removal in melt was confirmed as expected.