低硅铁尾矿制备加气混凝土及蒸压养护动力学研究

发布时间：2018-02-11 19:31

  本文关键词： 铁尾矿 加气混凝土 蒸压养护 动力学过程 托贝莫来石　出处：《武汉理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：铁尾矿是工业废弃物的主要类型,目前多堆存在尾矿库中,对矿山周边环境造成很大的影响。随着矿产资源的贫化和尾矿堆存量的增多,针对尾矿的综合利用研究逐渐成为热门课题。加气混凝土是一种新型建筑材料,拥有质轻、防火、保温、抗震等诸多优点,应用在建筑中能够有效节能,提高能源利用率。利用尾矿制备加气混凝土作为处理选矿尾矿的有效方法之一,不仅能够大量消纳堆存的尾矿,缓解矿山尾矿库建设和维护的压力,同时能为建材市场提供优质的产品,也为加气混凝土生产原料开辟新的途径。利用河北平泉富有公司低贫钒钛铁尾矿为主要硅质原料,掺入适量的硅砂、石灰、水泥等添加物后制备加气混凝土。系统研究了该铁尾矿制备加气混凝土工艺过程中的物料配比和蒸压养护制度等,探讨了蒸压养护反应动力学过程,并对制备过程中的反应机理进行了阐述。河北平泉钒钛铁尾矿粒度较粗,-0.074 mm粒级仅占21.07%,SiO2含量为40.46%。试验研究结果显示,加气混凝土制备的最佳物料配比为尾矿:硅砂:石灰:水泥:石膏=32:35:21:10:2,铝粉掺量为0.08%,水料比为0.57。蒸压养护过程升温时间为2 h,恒温时间为8 h,恒温温度为178℃,并采用自然降温方式。加气混凝土制品的抗压强度和绝干容重的平均值分别为3.98 MPa和622.1 kg/m3,已经达到国家标准对A3.5B06规格加气混凝土的要求。针对蒸压养护反应过程动力学研究的结果显示,蒸压养护恒温阶段的原料反应速度主要受反应物在水化产物层中的扩散速度所控制,加气混凝土制备原料中的SiO2-Ca(OH)2-H2O体系的反应过程可以用反应物通过产物层的扩散模型来描述,其动力学方程式为2/31?2/3x?(1?x)?0.792 exp(?19269/RT)t?b。蒸压养护过程中硅质材料和钙质材料在高温高压环境中发生了一系列水热合成反应,水化反应产物类型逐渐从高碱度转变为低碱度,同时结晶度不断完善,结构也逐渐变得更为致密,最终制品中的主要化学成分为托贝莫来石、CSH、水化石榴石以及未反应完全的SiO2,片状的托贝莫来石和CSH凝胶相互胶结形成整体强度。
[Abstract]:Iron tailings are the main types of industrial waste. At present, there are many piles in tailings reservoir, which have a great impact on the surrounding environment of mines. With the depletion of mineral resources and the increase of tailings heap stock, The study of comprehensive utilization of tailings has gradually become a hot topic. Aerated concrete is a new type of building material, which has many advantages such as light weight, fire resistance, heat preservation, earthquake resistance, etc., which can be used in building to save energy effectively. Using tailings to prepare aerated concrete is one of the effective methods to deal with tailings, which can not only absorb large amounts of tailings, but also relieve the pressure of construction and maintenance of mine tailings. At the same time, it can provide high quality products for the building materials market, and also open up a new way for the production of aerated concrete raw materials. Using the low and poor vanadium titanium-iron tailings of Pingquan Rich Company in Hebei Province as the main siliceous raw materials, with appropriate amount of silica sand and lime, Aerated concrete was prepared after adding cement and other additives. The material ratio and autoclaved curing system in the process of preparing aerated concrete by iron tailings were studied systematically, and the kinetic process of autoclaved curing reaction was discussed. The reaction mechanism in the process of preparation was described. The particle size of Hebei Pingquan vanadium ferric titanium tailings is coarse and -0.074 mm. The content of Sio _ 2 is 40.46. The experimental results show that the content of Sio _ 2 is 40.46 mm, and the content of Sio _ 2 is 40.46 mm. The optimum material ratio of aerated concrete is tailings: silica sand: lime: cement: gypsum 32: 35: 21: 10: 2, aluminum powder 0.08, water / material ratio 0.57.The temperature rise time of autoclaved curing process is 2 hours, the constant temperature time is 8 hours, and the constant temperature temperature is 178 鈩，

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