生石灰吸水特性对钒钛磁铁精粉烧结制粒的影响

Effects of water absorbing characteristics of quicklime on granulation of the vanadium titano-magnetite concentrate fines

为改善钒钛磁铁精粉的烧结制粒效果,采用微型圆筒制粒机研究了生石灰的吸水特性对钒钛磁铁精粉烧结制粒的影响。研究结果表明:不同生石灰的吸水特性差异较大,随着生石灰吸水特性指数的增大,钒钛磁铁精粉的颗粒长大指数、均匀性指数和抗热粉化指数先升高后降低,破损指数先降低后升高;相对于中钛型和高钛型钒钛磁铁矿,吸水特性指数对低钛型钒钛矿破损指数和抗热粉化指数的影响较小;增加吸水能力强的生石灰使用配比,有利于制粒性能的改善;但生石灰吸水能力过高时,其消化反应剧烈,消化后的黏性大,容易出现"自团聚"现象,造成其在混合料发生偏析,且水分在矿粉颗粒间的分布占比下降,矿粉颗粒间形成毛细力的水分不足。因此,对于吸水能力过高的生石灰,制粒中应适当调整配水量和加水方式使其均匀分布,同时保证铁矿粉之间形成毛细水的含水量,进而提高钒钛磁铁精粉的制粒效果。

In order to improve the sintering granulating effects of vanadium titano-magnetite concentrate,the effects of water absorbing characteristics of quicklime on the granulation of the vanadium titano-magnetite concentrate are investigated using micro-drum granulation equipment.The results show that there exists great difference for the water absorbing index(WAI)of different kinds of quicklime.With the increase of the WAI,the granulation index(GI),uniformity index(UI),and resistance index of the thermal disintegration(KI) of vanadium titano-magnetite concentrate first increase and then decrease,but the damage index(DI)exhibits the opposite behavior.Compared with medium-titanium and high-titanium vanadium titano-magnetite concentrate,the effects of WAI on the KI and DI are little for low-titanium vanadium titano-magnetite concentrate.Increasing the proportion of quicklime with strong water absorbing capacity is favorable for improving granulating performance,but when the WAI of quicklime is too high,the digestion reaction will be strong and the viscosity increases,which easily leads to "self-reunion" phenomenon and result in flux segregation in mixture.Meanwhile,the proportion of water distributed in the ore particles decreases,the water required for forming the capillary force among the ore particles is insufficient.Therefore,for the quicklime with high WAI,the water content and water adding methods can be adjusted in the granulation process for the flux uniform distribution and appropriate moisture of the ore particles,so as to improve the granulating effect of vanadium titano-magnetite concentrate.