钒尾矿制备泡沫混凝土的研究

发布时间：2018-03-31 02:09

本文选题：钒尾矿　切入点：活化方式　出处：《河北工程大学》2017年硕士论文

【摘要】：钒尾矿是工业酸浸提钒中所产生的固体废弃物。由于钒矿中V_2O_5品位较低,且尾矿性质受原始矿物、选矿工艺的影响存在较大差异,导致其难于回收利用。造成了大量钒尾矿堆存,给经济、环境带来负面影响。基于此本文以陕西山阳钒尾矿为研究对象,在对钒尾矿特性研究的基础上,进行了钒尾矿的活化方式研究以及初步验证了钒尾矿制备泡沫混凝土的技术可行性。为钒尾矿的综合利用提供基础理论支撑。对钒尾矿进行基本性质研究。钒尾矿化学组成中存在较高SiO_2含量达64.2%,主要以石英的形式存在,还伴有少量的石膏、长石、黄铁矿等矿物。同时运用不同的活化方式对钒尾矿进行活化,并运用活性指数K28对不同活化方式下钒尾矿的活性进行评价。结果表明机械粉磨复合碱性激发剂的方式对钒尾矿活性增强作用最为显著,活性指数可达85.1%。经此方式活化的钒尾矿可作为较理想的硅质材料用于建筑制品生产中。通过单因素试验、正交试验,综合考虑钒尾矿的利用率以及泡沫混凝土制品性能,得出了制备钒尾矿泡沫混凝土的优化配合比(质量百分数):钒尾矿40%、矿渣34%、石灰5%、水泥熟料13%、石膏8%,外加干料总量的0.07%的铝粉,水料比为0.6。此时制品抗压强度为3.70MPa、绝干密度为592kg/m3。满足JG/T 266-2011《泡沫混凝土》行业标准要求的A06、C3.5级泡沫混凝土要求。通过XRD、SEM分析对水化过程反应机理进行研究,分析了钒尾矿泡沫混凝土制品强度的来源。得出了在碱激发和硫酸盐激发共同作用下,矿渣和尾矿颗粒表面的硅氧四面体和铝氧四面体发生键的断裂和重组,生成C-S-H凝胶和钙矾石。针棒状的钙钒晶体穿插在凝胶孔隙中生长,将提高凝胶材料整体密实度,提升制品强度。使用专业图形分析软件“Image-Pro Plus”对钒尾矿泡沫混凝土断面孔的分布状况进行分析,研究孔结构的分布状况对制品性能的影响,为孔结构与制品性能的相关性研究提供一定的理论基础。结果表明当制品原料组分基本相同,且制品孔隙率大致相当时,气孔结构分布状况将对制品强度性能产生较大的影响。当气孔孔径较为集中的分布在平均孔径左右时得到的制品抗压性能最佳。
[Abstract]:Vanadium tailing is a solid waste produced by extracting vanadium from industrial acid. Because the V_2O_5 grade in vanadium ore is low and the properties of the tailings are affected by the original minerals, there are great differences in the processing process. As a result, it is difficult to recycle vanadium tailings, which results in a large amount of vanadium tailings, which brings negative effects to economy and environment. Based on this, this paper takes Shanyang vanadium tailings in Shaanxi as the research object, and based on the study of vanadium tailings, the characteristics of vanadium tailings are studied. The activation mode of vanadium tailings was studied and the technical feasibility of preparing foam concrete from vanadium tailings was preliminarily verified. The basic theoretical support for the comprehensive utilization of vanadium tailings was provided. The basic properties of vanadium tailings were studied. The chemical composition of the ore contains a high SiO_2 content of 64.2%, mainly in the form of quartz. Also accompanied by a small amount of gypsum, feldspar, pyrite and other minerals. At the same time, using different activation methods to activate vanadium tailings, The activity of vanadium tailings under different activation modes was evaluated by using activity index K28. The results showed that the activity of vanadium tailings was enhanced most obviously by mechanical grinding combined with alkaline activators. The activity index can reach 85.1. The vanadium tailings activated in this way can be used as ideal siliceous materials in the production of building products. By single factor test and orthogonal test, the utilization ratio of vanadium tailings and the properties of foam concrete products are considered synthetically. The optimum mix ratio of vanadium tailings foamed concrete was obtained (mass percent: 40% vanadium tailings, slag 34, lime 5, cement clinker 13, gypsum 8, aluminum powder 0.07% of the total dry material added, The ratio of water to material is 0.6. The compressive strength of the product is 3.70 MPA and the absolute dry density is 592 kg / m ~ 3. It meets the requirements of JG/T 266-2011 "foam concrete" industry standard. The reaction mechanism of hydration process is studied by XRD-SEM. The source of strength of vanadium tailings foam concrete products is analyzed. The bond fracture and recombination of SiO2 tetrahedron and aluminotetrahedron on the surface of slag and tailings are obtained under the combined action of alkali excitation and sulfate excitation. The formation of C-S-H gel and ettringite. The needle-rod calcium vanadium crystal grows in the gel pore, which will increase the overall compactness of the gel material. Using the professional graphic analysis software "Image-Pro Plus" to analyze the distribution of the broken face of vanadium tailings foam concrete, and to study the influence of the distribution of the pore structure on the properties of the products. It provides a theoretical basis for the study of the correlation between the pore structure and the properties of the products. The results show that when the components of the raw materials are basically the same and the porosity of the products is about the same, The distribution of stomatal structure will have a great influence on the strength properties of the products, and when the pore size is concentrated in the average pore size, the compressive properties of the products are the best.
【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528.2

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