块状铁矿石竖炉磁化焙烧的工艺优化

竖炉磁化焙烧是处理难选红铁矿较有效的方法。通过对弱磁块矿竖炉磁化焙烧的试验研究，提出了更加科学、高效的竖炉磁化焙烧理论，在现有鞍山式竖炉的基础上，通过高效控制铁矿石竖炉磁化焙烧还原气氛，对竖炉磁化焙烧工艺进行了优化。结果表明：还原气体H2体积分数提高到12%±1%，同时降低CO体积分数，提高块矿焙烧还原温度，可获得最佳的磁化焙烧效果；通过独立设置铁矿石磁化焙烧还原煤气系统与加热煤气系统，可实现还原煤气的成分、流量、压力灵活调节；通过减少还原煤气总量，将矿石还原煤气量降低至1400～1600m3/h，降低竖炉的生产成本；通过独立的还原煤气系统，提高还原煤气中焦炉煤气比例，将H2体积分数控制在12%±1%，矿石磁化率控制在2.33左右，降低了竖炉磁化焙烧煤气消耗，提高矿石磁化焙烧质量；为保证还原煤气降低用量后的压力和喷出的均匀性，将还原煤气喷出塔的出口面积缩小50%，使矿石能够充分、均匀地完成还原。

Process optimization on magnetic roasting of lump iron ore in shaft furnace

Magnetic roasting in shaft furnace is an effective method to dispose refractory red iron ore. A more scientific and efficient shaft furnace magnetic roasting theory is put forward through the experimental research on haft furnace magnetic roasting of weakly magnetic lump iron ore. And based on the existing Anshan- type shaft furnace, shaft furnace magnetic roasting process is optimized via controlling reducing atmosphere efficiently. The results show that the maximum effectiveness of magnetic roasting is obtained under the condition that the content of hydrogen reduction gas increases to 12%±1%, the CO content decreases and the magnetic roasting reduction temperature rises. And by independently setting the reduction gas and heating gas system in the process of magnetic roasting, the flexible adjustment for reducing gas components, flow rate and pressure is achieved. Decreasing the amount of reduction gas to reduce the gas for reduction of ore to 1400- 1600m3/h can lower the production cost of shaft furnace. The independent reduction gas system can increase coke oven gas proportion of reduction gas and keep the H2 content and the magnetic susceptibility to 12%±1% and to 2.33 respectively, which can decrease gas reduction and improve the quality of ore magnetic roasting. At the same time, the export area of gas jet tower will be decreased by 50% in order to keep the stable gas pressure stability and the uniformity of the gas burner. In this way can the ore be reduced fully and evenly.