钙和镁添加剂在氧化球团中的应用

Application of Ca,Mg-additives in oxidized pellets

对石灰石、菱镁石和白云石3种钙、镁添加剂对球团性能、TFe品位以及生产工艺的影响进行研究。研究结果表明:添加剂降低了生球落下强度和预热球抗压强度,但提高了生球爆裂温度;添加剂中的CaO使焙烧球抗压强度先升高后降低,MgO使得焙烧球抗压强度降低;加入钙、镁添加剂会降低球团矿TFe品位,通过添加生石灰或有机黏结剂取代膨润土,可以提高球团的TFe品位;钙、镁添加剂在干燥预热段分解吸热会影响链篦机的热平衡,通过在球团中内配无烟煤,由无烟煤燃烧放热来提供钙、镁添加剂热分解所需的热量,可以维持链篦机的热平衡制度;通过添加生石灰或有机黏结剂和内配适量的无烟煤,可解决钙、镁添加剂在氧化球团中应用的难题。

The effects of adding Ca and Mg-additives,such as limestone,magnesite and dolomite on the properties of pellets,and the content of Fe and the production process were studied.The results show that adding additives decrease the drop strength of green pellets and the compressive strength of preheated pellets,improve the crack temperature,and CaO in additives can increase the compressive strength of fired pellets firstly but then decrease,and MgO can decrease the compressive strength of fired pellets.The content of Fe will drop when adding additives,but it can be increased by adding lime or organic binder to replace bentonite.Decalescence of the Ca and Mg-additives decomposition in drying and preheating will affect the thermal equilibrium of grate.The combustion heat that offered by adding anthracite can provide the heat of decomposition of Ca and Mg-additives,which can keep the thermal equilibrium of grate.So,the difficulty of applying Ca and Mg-additives into oxidized pellets can be resolved by adding lime or organic binder suitable anthracite.