超纯铁精矿粉直接还原制备超细铁粉

将超纯铁精矿粉气流粉碎到微米级,用氢气直接还原制备超细铁粉,利用正交实验法研究还原温度、时间、氢气流量等工艺参数对还原率的影响。结果表明:对超纯铁精矿粉还原率的影响程度从大到小依次为温度、时间、氢气流量,综合考虑生产成本,确定最佳的还原工艺参数为温度780℃、时间60 min、氢气流量0.3 L/min。在此工艺条件下得到的超细铁粉,全铁含量为98.58%,氢损0.45%,酸不溶物含量为0.19%,其化学成分符合粉末冶金用铁粉标准,一次粒度小于5μm。

Ultra-fine iron powder prepared by directly reducing super iron concentrates

The ultra fine iron powder was produced through directly reducing the super iron concentrates by H2, the super iron concentrates were milled into micrometer scale by jet mill machine before reducing. The effects of reducing temperature, time and flow rates of H2 on the reduction rate of super iron concentrates were studied by orthogonal experiments. The results show that the significantly descending order of parameters on the reduction rate is temperature, time and H2 flow rate. Considering the energy consumption, the optimal reducing parameters are 780℃ for 60 min with H2flow rate of 0.3 L/min. The iron powder produced under these parameters has an Fe content of 98.58%, hydrogen loss of 0.45% and acid insoluble content of 0.19%. The chemical constituent of the iron powder is consistent with the correspondent Chinese standards, and the primary particle size of this powder is smaller than 5mm.