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

碳化铁有望作为一种新的铁源替代废铁用于炼钢，特别是在电弧炉中使用。本研究的目的是在流化床中生产高质量的碳化铁，并研究其注入钢液中的熔化行为，以明确其在不久的将来可用于炼钢的可行性。以下结果是在三年内得出的。在1995年，新建了一个流化床（62mm内径），用于生产碳化铁（Fe3C， 6.7质量%，直径：0.1-1 mm）。在新的工艺概念的基础上，用我们指定的气体在8000℃左右反应铁矿石，进行了一些初步的生产试验。1996年和1997年，用同样的方法在流化床中成功生产了许多高质量的碳化铁。在50kg的感应炉中，通过喷枪将含氩气的碳化铁吹至钢液表面，进行了熔炼试验。通过测量熔体和出口气体中温度和物质含量的变化来评估质量和热平衡。碳化物被证明可以毫无问题地溶解在熔体中。它们的熔化热随渗碳程度的升高而降低。同时，熔体脱氮效果与预期一致。

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.