预热焙烧参数对超细粒度磁铁矿粉球团性能的影响

 国内某磁铁精矿粉粒度非常细,小于0.044mm的比例达到89%，对其制备的球团矿的预热焙烧性能进行试验研究，小型管式炉焙烧试验结果表明，预热焙烧温度太高或高温下预热焙烧时间过长，球团矿外层易形成硬壳，阻碍球团矿的进一步氧化，球团矿强度反而下降。矿相鉴定结果表明，预热焙烧球团矿的外层、中层、里层的氧化程度不同，整体来看，外层氧化速度快，氧化较好，而中层和里层氧化逐渐减弱，预热焙烧温度高或高温预热焙烧时间长是球团矿外层易形成硬壳的主要原因。因此，对于超细粒度磁铁矿粉球团矿，预热焙烧温度太高或高温下预热焙烧时间过长，反而不利于球团矿强度的提高。

Effect of Preheating and Roasting Parameters on Pellet Property of Super-Fine Magnetite Concentrate

One kind of super-fine magnetite concentrates with nearly 89% of the material being minus 0.044mm was investigated to make the pellets. The results show that the compression strength of preheated and finished pellets would decrease when the pellets being preheated or roasted at higher temperature or longer time. Much more research work was performed on the changes of mineral composition on different layer of the pellet. The results shows the oxidization process demonstrating different intensity on different layer, which means that the outer layer exhibiting stronger oxidization intensity, while mediate and inner layer get weaker oxidization intensity. So the outer layer get crusted layer easily at higher preheating and roasting temperature or longer time, which would prevent the oxidization process for inner and median layer pellet and the compression strength of preheated and finished pellets get decreased. The whole experiments show that it is not conducive to the increase of compression strength for preheated and finished pellets with higher preheating and roasting temperature or longer time.