铁矿粉流化床直接还原防止粘结的试验研究

Experimental Study on Sticking Prevention in Fludized Bed Reduction of Iron Ore Powder

研究了流化床铁矿粉直接还原过程中掺入惰性物质对防止粘结的效果以及粘结失流与铁矿的组成、粒度、还原温度、还原气氛、金属化率、掺入惰性物质种类、数量等多种因素的关系,探讨了粘结失流机理。结果表明:MgO是最有效的防止粘接添加剂,使用量小于5%;CaO次之,使用量约为5%～10%。少量焦粉、白云石、碳酸钙等对抑制粘结失流无明显的作用。铁矿的熔点越低、粒度越小、金属化率越高、温度越高就越容易失流。

The sticking of iron ore powder restricts the reduction of iron ore in fludized bed.The effects of sticking prevention by adding inert material into fludized bed,and the relationship between defluidization and composition and size of iron ore,reduction temperature and atmosphere,metallization rate,and kinds and quantity of inert material etc.are probed into through experiment in this paper.Then the mechanism of sticking is discussed.MgO is the best additive for sticking prevention with an adding amount below 5%;CaO comes second with the adding amount of 5%~10%.Small amount of coke powder,dolomite,and CaCO3 has little effect on sticking prevention.The lower melting point,the smaller size,and the higher metallization rate and temperature the iron ore powder has,the easier it becomes defluidized.