镜铁矿粉矿微波磁化焙烧工艺及机理研究

发布时间：2018-05-14 04:20

  本文选题：镜铁矿粉矿 + 微波磁化焙烧　； 参考：《武汉科技大学》2015年硕士论文

【摘要】：镜铁山镜铁矿是酒钢主要原料，由于其矿物组成复杂，矿物粒度嵌布极细且不均匀，矿物颗粒纯度低，铁矿物与脉石矿物比磁化系数、密度等物理参数相近或有交叉，通过常规选矿方法选别较为困难。研究表明，这类难选铁矿采磁化焙烧处理可以达到较好的选别指标，但常用的磁化焙烧工艺因设备或工艺原因对这类粉矿不能有效处理，，而微波加热应用于铁矿碳热还原具有其独特优势：①加热速度快，加热均匀，减少矿物还原时的“夹生”现象；②微波加热具有选择性，矿物内部容易产生裂纹，促进气固还原反应进行，同时裂纹的产生有利于降低磨矿能耗；③可以直接使用粉矿加热，简化工艺流程。因此，研究微波磁化焙烧工艺对于该类难选铁矿物的回收利用具有重要意义。 本研究以镜铁山镜铁矿粉矿为原料，进行了微波磁化焙烧-磁选试验研究，确定了该镜铁矿微波磁化焙烧的工艺参数，并结合矿物微观结构变化探讨了微波加热对磁化焙烧过程影响的作用机理。 该镜铁矿粉矿采用微波加热磁化焙烧时，以固定碳占原矿质量的2.5%配加烟煤、在微波功率1000W、焙烧温度550℃、保温15min条件下焙烧，焙烧矿经球磨机磨细至-0.074mm占85%左右、通过磁场强度为92.16kA/m的磁选管选别，可得铁品位55.16%，回收率86.65%的理想指标。 镜铁矿粉矿经微波焙烧后，矿样中镜铁矿、菱铁矿、褐铁矿均已转化为磁铁矿，微波加热应用于该镜铁矿磁化焙烧效果较好。微波磁化焙烧会导致矿石内部产生裂纹，但不同铁矿产生的裂纹形式有一定差异。由镜铁矿转化而来的磁铁矿内部产生裂纹较少，裂纹主要产生于铁矿与脉石界面之间以及脉石矿物内部，而由菱铁矿转化而来的磁铁矿裂纹的主要形式为矿物从内部龟裂，使矿石结构变得疏松。微波磁化焙烧对矿物结构破坏是微波选择性加热促进矿物产生裂纹以及菱铁矿受热分解双重作用结果。 微波加热应用于该镜铁矿磁化焙烧工艺可以促进矿物内部产生裂纹，降低磨矿能耗，同时能够促进铁矿物与脉石矿物解离，有利于后续磁选分离。
[Abstract]:Jingtieshanjing iron mine is the main raw material of Jiugang. Because of its complex mineral composition, fine and uneven distribution of mineral particle size, low purity of mineral particle, the ratio of iron mineral to gangue mineral magnetization coefficient, density and other physical parameters are close or cross. It is difficult to separate ore by conventional dressing method. The results show that the magnetization roasting treatment of refractory iron ore can achieve a better separation index, but the common magnetization roasting process can not effectively treat this kind of ore because of equipment or process reasons. However, microwave heating has its unique advantage in the reduction of iron ore by carbothermal reduction, which is characterized by high heating speed and uniform heating. Microwave heating can reduce the phenomenon of "pinch" in the reduction of minerals. Microwave heating is selective, and cracks are easy to occur in minerals. The gas-solid reduction reaction is promoted, and the crack generation is beneficial to reduce the energy consumption of grinding. The pulverized ore can be heated directly and the technological process can be simplified. Therefore, it is of great significance to study microwave magnetization roasting technology for the recovery and utilization of refractory iron ore. In this study, the microwave magnetization roasting and magnetic separation experiments were carried out with the mirror iron ore as raw material, and the technological parameters of the microwave magnetization roasting of the mirror iron ore were determined. The mechanism of the effect of microwave heating on magnetization roasting process was also discussed. When magnetized roasting with microwave heating, fixed carbon is used to add bituminous coal to 2.5% of the raw ore mass, calcined at microwave power 1000W, calcination temperature 550 鈩

本文编号：1886302