铁矿粉流态化还原过程黏结机理分析  

Sticking Mechanism Analysis of Fine Iron Ore in Fluidized-Reduction Process

作　　者：徐其言[1] 王建军[1] 郭磊 

机构地区：[1]安徽工业大学,冶金工程学院,安徽马鞍山243000 [2]钢铁冶金新技术国家重点实验室,北京100083

出　　处：《金属矿山》2016年第2期108-111,共4页Metal Mine

摘　　要：为探究常压下铁矿粉颗粒在流化床中进行还原时的颗粒间黏结失流情况,指导用流化床还原铁矿粉的工业化应用,以澳大利亚某铁品位为61.42%、颗粒粒径为0.63~1.0 mm的铁矿粉为原料,添加与铁矿粉质量比为2%的Mg O粉末,在还原温度为923~1 023 K、H2与CO体积比为4∶1的混合气体为还原气体、还原气体线速度为0.6m/s、还原时间为60 min条件下,考察铁矿颗粒在流化床中还原时的受力情况。结果表明：颗粒在流化床中的存在状态主要受气体对颗粒的曳力、颗粒间的黏结力以及颗粒自身重力作用的影响。颗粒在竖直方向上所受向上的合外力大于零时,处于流化状态;合外力等于零时,铁矿粉处于临界黏结状态;合外力小于零时,处于黏结失流状态。温度相同时,颗粒间黏结力随着固体桥半径增大而增大;当固体桥半径相同时,高温条件下颗粒间的黏结力比低温条件下要大,黏结失流的临界固体桥半径范围为82~106 nm。To guide the fluidized bed industrial application, exploring the ordinary conditions of fine iron ores in the fluidized bed to restore loss of flow between fine iron ore particles. A process with Australia fine iron ore with 61.42% iron is reduced in fiuidized bed at the experimental conditions include 923 K to 1 023 K temperatures ,particle size range of 0. 63 mm to 1.0 mm, coating MgO accounting for 2% of the total quality of fine iron ore, the volume ratio ofearbon monoxide and H2 and CO monoxide is 4 ： 1 ,linear velocity of O. 6 m/s, reduction time is 60 min, and observe the force of fine iron ores in the reduc- tion process. The results show that the particles in the fluidized bed are mainly affected by gas drag force of particles, the bond- ing force between particles and particles the result of its own gravity. Particle sticking is affected by the external force, which is given by the following formula,when the force is over zero,fine iron ore is in fluidization state;when the force is equal to zero, the fine iron ore is in critical sticking state;and when the force is below zero, fine iron ore is in the defiuidizatiou state. Bonding force increases as the solid bridge radius increases at the same temperature and the bonding force between particles is bigger at higher temperature when the radius of solid bridge is the same. Under the experiment conditions, the critical radius of solid bridge is 82 - 106 nm.

关 键 词：流化床 流态化 黏结 固体桥 

分 类 号：TF046.2[冶金工程—冶金物理化学]