返矿影响烧结过程的机理研究

Research on mechanism of return fines affecting sintering process

为研究烧结返矿中大粒级占比对烧结生产指标的影响,通过化学分析、XRD分析、热重分析等对烧结返矿的各项理化性能进行了分析研究,并利用微型烧结实验装置及烧结杯模拟实验就返矿中+5 mm粒级占比对烧结指标的影响进行了实验研究。结果表明:返矿中不同粒级的成分存在较大差异;随着返矿粒级的增大,其矿物物相中磁铁矿和铁酸钙的量增加;返矿粒级越大,其同化温度、熔化温度越高,返矿粒级越小,越有利于液相生成;当返矿+5 mm的占比超过25%时,混合料制粒效果变差,同时其烧结成品率、转鼓强度均下降,固体燃耗升高,烧结矿成品粒级组成中5~10 mm的粒级占比上升。因此,在烧结生产配料过程中需控制返矿中+5 mm的粒级占比低于25%。

In order to research the influence of the proportion of large particle size fraction in sintering return fines on the index of sintering production, the physical and chemical properties of sintering return fines are analyzed by chemical analysis, XRD analysis, thermogravimetric analysis, etc.The influence of the proportion of +5 mm particle size fraction on sintering index is studied by using micro sintering experimental device and sintering cup simulation experiment.The results show that, the composition of different particle sizes in the return fines is also quite different;as the particle size of the return fines increases, the amount of magnetite and calcium ferrite in the mineral phase increases.The larger the particle size of return fines is, the higher the assimilation temperature and melting temperature are, and as the particle size of return fines gets smaller, it becomes more conducive to the formation of liquid phase.When the proportion of return fines +5 mm is more than 25%,the granulation effect of the mixture becomes worse, the sintering yield and drum strength decrease, the solid fuel consumption increases, and the proportion of 5~10 mm in the particle size composition of sinter products also increases.Therefore, it is necessary to control the proportion of +5 mm in the return fines less than 25% in the sintering production proportioning process.