配加不同粒度镁橄榄石对球团矿性能的影响

Effect of magnesium olivine particle size on the performance of pellet

本文使用挪威Sibelco公司提供的大粒度镁橄榄石作为镁质添加剂进行造球试验,通过对镁橄榄石进行不同时间的预磨处理,研究其粒度对球团性能的影响。使用化学分析、X射线衍射分析及扫描电镜-能谱分析等手段对造球原料及试验结果进行分析,结果表明:增加镁橄榄石预磨时间有利于提高球团生球性能;焙烧后球团中存在两种孔隙,液相生成导致的圆形大气孔及赤铁矿连晶间的孔隙,二者均对球团强度有一定影响;随着预磨时间增加,球团中大气孔形状和分布逐渐变得均匀,气孔直径逐渐变大,赤铁矿连晶间孔隙尺寸及数量逐渐变小,球团抗压强度先增加后缓慢降低,孔隙率变化呈现相反的趋势;镁橄榄石最佳预磨时间为40 min,此条件下镁橄榄石及生产的球团均可满足生产实践要求。

A type of large-grained magnesium olivine was used as Mg additive to prepare pellet. Effect of olivine particle size distribution was studied by changing pre-grinding time of olivine. Properties of raw materials and prepared pellets were analyzed by Chemical analysis, XRD, SEM-EDS, etc. Results showed that, the pre-grinding time of the magnesium olivine is beneficial to improving the performance of green pellet, there are two kinds of pores in the roasted pellet, the circular large pores caused by liquid phase generation and hematite intergranular pores, both of which have a certain effect on the strength of pellet. With the increase of the pre-grinding time, the shape and distribution of circular large pores in pellets gradually become uniform, pore size and quantity of hematite intergranular pores become smaller, compressive strength of the pellet increased at first and then decreased slowly, porosity changes in the opposite direction. The optimal pre-grinding time of magnesium olivine is 40 min, under which condition can the olivine and pellet meet the requirements of production practice.