某磁铁精矿内配碳直接还原试验研究

Experimental Study on Direct Reduction for a Carbon-containing Magnetite Concentrate

为探究直接还原铁新工艺并提高产品质量,以全铁含量为64.71%的某低硫磁铁精矿为原料,糊精为有机粘结剂,采用内配焦炭制备生球团,在氮气的保护下进行还原焙烧试验。结果表明:在焦炭用量为20%、还原温度为1150℃、还原时间为1 h、糊精添加量为1%、磨矿细度为-0.074mm占80%、磁场强度为80 kA/m的条件下,可获得全铁含量为92.67%的直接还原铁产品,此时铁回收率为95.74%;内配1.6%的碳酸钠后,直接还原铁产品的全铁含量达到93.55%,提升近一个百分点,而铁回收率降至94.20%。SEM-EDS分析显示直接还原铁产品晶粒较大,金属铁衍射峰明显,可作为电炉炼钢中替代废钢的优质原料。

In order to explore the new technology of direct reduction iron and improve product quality,carbon was added in a low sulfur magnetite concentrate with the total iron contents of 64.71%for the preparation of raw pellets and dextrin as organic binder.Then,the reduction roasting tests were carried out under the protection of nitrogen.The results showed that under the conditions of coke dosage of 20%,reduction temperature of 1150℃,reduction time of 1 h,dextrin addition of 1%,grinding fineness of-0.074 mm accounting for 80%and magnetic field intensity of 80 kA/m,direct reduced iron product with total iron contents of 92.67%and iron recovery rate of 95.74%was obtained.With the addition of 1.6%sodium carbonate,the total iron contents of the direct reduced iron product reached 93.55%,which increased by nearly one percentage point,and the iron recovery rate decreased to 94.20%.SEM-EDS analysis showed that the product has large grain size and obvious metal iron diffraction peak,which can be used as high quality raw material to replace scrap steel in electric furnace steelmaking.