酒钢干磨铁矿悬浮磁化焙烧—磁选分离实验研究

Experimental Study on Suspension Magnetization Roasting−Magnetic Separation of Dry Grinding Iron Ore from Jiuquan Iron and Steel Company

  • 摘要: 磁化焙烧工艺是处理复杂难选铁矿石最有效的手段之一,以酒钢干式制粉样品为研究对象,聚焦干法磨矿与悬浮磁化焙烧的衔接优势,系统开展悬浮磁化焙烧−磁选分离试验。通过考察焙烧温度、还原气浓度、焙烧时间、磨矿细度及磁选场强等关键参数对分选指标的影响,确定了最佳工艺条件。原矿中主要有用矿物为赤铁矿和菱铁矿,悬浮磁化焙烧—磁选试验结果表明,在焙烧温度475 ℃、CO体积浓度20%、焙烧时间6 min、磨矿细度−0.125 mm占比100%、磁场强度160 kA/m的条件下,可获得铁品位56.75%、铁回收率91.71%的磁选精矿。物相与成分分析表明,焙烧过程中赤铁矿和菱铁矿高效转化为磁铁矿,磁选后精矿中磁性铁分布率达93.25%,有害元素含量显著降低。本研究突出了干法磨矿在简化流程、降低能耗及与焙烧环节顺畅衔接方面的优势,为悬浮磁化焙烧技术在难选铁矿资源中的应用提供了新的工艺组合路径与技术支撑。

     

    Abstract: Magnetizing roasting stands as one of the most effective techniques for processing complex and refractory iron ores. This study investigated the synergistic advantages of integrating dry grinding with suspension magnetizing roasting, using dry−processed powder samples from Jiuquan Iron & Steel Group as the raw material. A systematic experimental program of suspension magnetizing roasting followed by magnetic separation was conducted. The research focused on elucidating the influence of key parameters—namely roasting temperature, reducing gas (CO) concentration, roasting duration, grinding fineness, and magnetic field intensity—on the separation efficiency to determine the optimal processing conditions. The primary valuable minerals in the raw ore were identified as hematite and siderite. The suspension magnetizing roasting−magnetic separation tests revealed that the following optimal conditions yielded the highest performance: a roasting temperature of 475 ℃, a CO volume concentration of 20%, a roasting time of 6 minutes, a grinding fineness of 100% passing 0.125 mm, and a magnetic field intensity of 160 kA/m. Under this optimized regime, a magnetic concentrate with an iron grade of 56.75% and an iron recovery of 91.71% was successfully obtained. Phase and component analyses demonstrate that during the roasting process, hematite and siderite are efficiently converted into magnetite. Post−separation, the distribution rate of magnetic iron in the concentrate reaches 93.25%, while the content of harmful elements is significantly reduced. This investigation highlights the inherent advantages of dry grinding, which simplifies the overall flowsheet, reduces energy consumption, and ensures seamless integration with the subsequent roasting stage. The findings provide a novel process combination and robust technical support for the application of suspension magnetizing roasting technology in utilizing challenging iron ore resources.

     

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