褐-赤复合型高磷铁矿直接还原-磁选实验

    Limonite-hematite Composite High-phosphorus Iron Ores by Direct Reduction and Magnetic Separation

    • 摘要: 为了实现某褐-赤复合型低品位复杂高磷铁矿的高效利用,进行了基于直接还原-磁选工艺制备铁精矿的实验研究,考查了还原温度、添加剂、还原剂种类等因素对高磷铁矿还原的影响。结果表明:随着温度从1 000 ℃升高到1 150 ℃,还原球团金属化率从28.65%增加到73.11%;碱度从0增加到1.2,还原球团金属化率先增加后降低,金属化率较高为76.52%;球团Na2CO3用量从2%增加到8%,还原球团金属化率先增加后降低,金属化率较高为74.36%;使用城市固废替代部分还原剂,随着置换比从0增加到60%,还原球团的金属化率增加后降低,较高金属化率为83.64%。在碱度为0.6、Na2CO3用量为4%、城市固废置换比为20%、还原温度为1 100 ℃和还原时间为30 min,还原后球团金属化率为83.64%。将上述还原球团进行磨矿磁选,在磨矿粒度小于0.03 mm,磁场强度为100 kA/m时,磁选后精矿产率、铁回收率、金属化率分别为50.81%、78.36%和48.81%。由于金属铁颗粒的尺寸较小,导致精矿产率和铁回收率整体偏低,继续研究如何实现金属铁颗粒的长大非常关键。

       

      Abstract: In order to achieve the efficient utilization of a certain limonite-hematite composite high-phosphorus iron ore, experimental research was conducted on the preparation of iron concentrate based on a direct reduction-magnetic separation process. The results indicate that with an increase in temperature from 1 000 °C to 1 150 °C, the metallization ratio of the reduction pellets increased from 28.65% to 73.11%. With an increase in alkalinity from 0 to 1.2, the metallization ratio of the reduction pellets initially increased and then decreased, reaching a maximum of 76.52%. As the dosage of Na2CO3 in the pellets increased from 2% to 8%, the metallization ratio initially increased and then decreased, reaching a maximum of 74.36%. When a portion of the reducing agent was substituted with municipal solid waste, as the substitution ratio increased from 0 to 60%, the metallization ratio of the reduction pellets initially increased and then decreased, reaching a maximum metallization ratio of 83.64%. With an alkalinity of 0.6, Na2CO3 dosage of 4%, municipal solid waste substitution ratio of 20%, reduction temperature of 1 100 °C, and reduction time of 30 min, the metallization ratio of the pellets after reduction reached 83.64%. The previously reduced pellets were subjected to grinding and magnetic separation. With a grinding particle size of less than 0.03 mm and a magnetic field intensity of 100 kA/m, the concentrate yield, iron recovery rate, and metallization ratio after magnetic separation were 50.81%, 78.36%, and 48.81%, respectively. Due to the relatively small size of metallic iron particles, there is an overall lower concentrate yield and recovery rate. Further research on achieving the growth of metallic iron particles is crucial to address this issue.

       

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