Development of new smelting process by using metal dusting

以赤铁矿粉和铁矿粒为原料，研究了碳化铁在高温（750℃以上）和低温（750℃以下）下的分解行为，作为金属粉生产细还原铁粉的基础性研究。利用流化床反应器对碳化铁的分解行为进行了研究。结果表明：(1)以赤铁矿为原料，用H_2-30vol%CH_4在750℃下合成碳化铁，在650℃和900℃时分解速度最快；650℃下碳化铁分解产生的多余碳量是900℃时的1/5。因此，碳化铁在650℃下的分解非常适合去除多余的碳。(2)采用粒度为250~600μm的铁矿进行了同样的实验，采用赤铁矿粉作为药剂获得了相同的结果。因此，金属除尘能够利用铁矿石颗粒。(3)用CO-20vol%C0_2在900℃下气化脱除碳化铁分解过程中产生的多余碳。650℃下产生的多余碳比900℃下产生的多余碳的去除率快，因为650℃下产生的多余碳量比900℃下少。(4)碳化铁分解过程中产生的多余碳，由于分解铁是烧结的，采用流化床反应器很难去除。

As a fundamental research for the production of fine reduction iron powder by using metal dusting, the decomposition behavior of iron carbide at high temperature (above 750℃) and low temperature (under 750℃) was investigated by using a reagent hematite powder and iron ore particle. Moreover, the decomposition behavior of iron carbide was investigated by using a fluidized bed reactor. The results obtained are summarized as follows:(1) The decomposition rate of iron carbide which synthesized from reagent hematite with H_2-30vol%CH_4 at 750℃ was fastest at 650℃ and 900℃. Moreover, the amount of excess carbon generated during decomposition of iron carbide at 650℃ was 1/5 times that at 900℃. Therefore, The decomposition of iron carbide at 650℃ is well suited to remove the excess carbon.(2) The same experiment was carried out by using iron ore particle (250~600μm) and the same results when reagent hematite powder was used were obtained. Therefore, metal dusting is able to use iron ore particle.(3) The excess carbon generated during decomposition of iron carbide was removed by gasification with CO-20vol%C0_2 at 900℃. The removal rate of excess carbon generated at 650℃ was faster than that at 900℃ because the amount of excess carbon generated at 650℃ was smaller than that at 900℃.(4) It is difficult to remove the excess carbon generated during decomposition of iron carbide by using a fluidized bed reactor because of sintering the decomposition iron.