窑尾钢渣直接外加法生产水泥熟料研究

发布时间：2018-06-08 15:20

  本文选题：粗颗粒钢渣 + 界面反应　； 参考：《中国建筑材料科学研究总院》2015年硕士论文

【摘要】：本研究通过X射线衍射(XRD)、扫描电镜(SEM)、水化热等手段,探究了粗颗粒钢渣在不同温度下煅烧后自身形貌及矿物的变化、粗颗粒钢渣与生料在高温煅烧下的反应机理以及外加不同掺量的粗颗粒钢渣对水泥熟料矿物的影响。研究表明,粗颗粒钢渣的掺入替代了部分水泥生料,降低了CO2的排放,同时碳酸钙的分解温度下降,有利于降低煅烧过程中能耗和气体排放。随着粗颗粒钢渣的掺入,熟料煅烧低共熔温度下降,促进了烧成熟料矿物中游离氧化钙的吸收,易烧性提高。经高温煅烧后,钢渣自身的矿物含量及种类也发生一定变化,其内部游离氧化物含量显著减少,钢渣中铁铝相胶凝矿物含量增加。RO相固溶体内部固溶氧化物组成发生明显变化,由以Fe O为主RO相转变为以Mg O为主RO相,温度越高,转化程度越大。通过对1350℃和1450℃下粗颗粒与生料界面的EMS形貌及XRD矿物相分析可得知,粗颗粒钢渣与生料的过渡区在不同温度均发生了化学反应,生成了以Fe、Al、Ca为主要元素的片状或团状矿物,结合X射线衍射分析可判断该过渡区域矿物为C4AF矿物,该过渡区反应主要由生料提供钙源,钢渣提供Fe、Al相,随着温度的升高,钢渣的反应参与度增加。粗颗粒钢渣的掺量低于20%时,生成的钢渣熟料易磨性较好。当钢渣掺量超过15%后,钢渣易磨性下降较为明显。钢渣的掺入导致水化速率和放热量均下降,早期强度呈现一定的下降,后期强度显著增加,增长率较快。在1450℃下煅烧后,掺15%粗颗粒钢渣样品28d水泥砂浆强度仅损失1.22Mpa,下降比例不超过3%。早期强度的下降主要是由于,钢渣的掺入,带入大量铁相,降低了生料的铝率,使熟料中C4AF含量上升,C3A含量下降。钢渣的掺入,早期水化后,孔径数量增多,随着龄期的延长,有害孔逐渐被填充,这也是掺钢渣熟料后期强度增长迅速的重要因素。通过将上述研究成果应用于湖南韶峰南方水泥有限公司日产2500吨的新型干法窑上,结果表明,粗颗粒钢渣的掺入,降低了水泥熟料中C3S和C3A的含量,增加了C2S和C4AF含量,从而降低了水泥的水化放热速率及放热量,为生产低热水泥和道路水泥提供了有利条件。同时C3S及C3A含量的上升,有利于提高水泥的抗硫酸盐腐蚀性能。以10%粗颗粒钢渣替代部分水泥生料能够烧制出游离氧化钙较低,强度较高,矿物分布均匀,结构致密的优质硅酸盐水泥熟料。
[Abstract]:By means of X-ray diffraction (XRD), scanning electron microscope (SEM), heat of hydration and so on, the morphology and mineral changes of coarse granular steel slag calcined at different temperatures were investigated. The reaction mechanism of coarse grain steel slag and raw meal under high temperature calcination and the effect of different amount of coarse grain steel slag on cement clinker mineral. The results show that the addition of coarse grain steel slag can replace some raw cement and reduce CO _ 2 emission, while the decomposition temperature of calcium carbonate is decreased, which is beneficial to reduce the energy consumption and gas emission during the calcination process. With the addition of coarse-grained steel slag, the low eutectic temperature of clinker calcination decreases, which promotes the absorption of free calcium oxide in clinker minerals and improves its burnability. After high temperature calcination, the mineral content and species of steel slag also changed to a certain extent, the content of free oxide in steel slag decreased significantly, and the content of iron and aluminum phase cementing mineral in steel slag increased. The composition of solid solution oxide in the solid solution of RO phase changed obviously. The higher the temperature is, the greater the transformation degree is when the RO phase is changed from Feo phase to MgO phase. The morphology and mineral phase of the interface between coarse grain and raw meal at 1350 鈩，

本文编号：1996252