赤泥—煤系偏高岭土地聚合物物理力学性质与机理研究

When we consider environmental challenges, industrial solid waste is nonnegligible. The storage of industrial solid waste (ISW) occupies a great quantity of land, meanwhile, the stability of landfills and pollution of contaminant to the environment are also the hidden dangers. Reutilization of industrial solid waste is a key issue vital to the national economy and people's livelihood. As the reutilization ratio of red mud and coal gangue is lower than 10% in China, to develop a new approach of reutilization these wastes becomes a development trend in the future. Considering the significant amounts of active constituent for polymerization (i.e., SiO2, Al2O3) in red mud and coal-metakalin (industry product of coal gangue), and the alkali activation of red mud, red mud and coal-metakalin are used as the parent materials in this research. A new material (geo-polymer) polymerized by red mud and coal-metakalin (CMK) will be developed, which will present a new approach of industrial solid waste (ISW) reutilization. The chemical composition, microstructure, and basic physical and mechanical properties will be tested using modern material testing technology to investigate the chemical mechanism and microscopic mechanism of polymerization and to determine the optimum prescription of geopolymer. This study will theoretically contribute to the production of geo-polymer. Experiment simulating the influence of different application environment (corrosion in saline and acid solution, freeze-thaw) to the geo-polymer will be taken out to evaluate durability of the geo-polymer, and the damage mechanics model of the geo-polymer in inorganic pollution environment, under freeze-thaw cycle will be established, which contribute to the method and theory for evaluation of the reliability and security of geo-polymer in different extreme application environment.

工业固体废弃物的堆放不仅占用大量土地，还存在堆放体的稳定安全和对环境污染的隐患，因此开展固废物的资源化利用事关国计民生。在我国赤泥、煤矸石等固体废弃物的综合利用率偏低于10%，因此研发新的资源化利用途径已成为新的热点问题。基于赤泥、煤系偏高岭土（煤矸石的再生产物）含有制备地聚合物所需的大量活性成分SiO2, Al2O3, 且赤泥的强碱性有助于聚合过程中的碱激发效应，本项目以赤泥和煤矸石固废物为研究对象，研发新型赤泥-煤系偏高岭土地聚合物，开辟其资源化利用的新途径。借助现代测试技术，化学机理分析，微观结构构建，揭示新型地聚合物的物理力学特性的化学微观机制和最佳配比，为定量制备该类地聚合物奠定理论基础。通过室内模拟试验，微/细观力学分析，建立在无机污染环境、冻融循环作用下该类地聚合物的损伤力学模型，为正确评估其在不同环境的工程应用中的可靠度和安全性提供理论依据和方法。

本项目以实现山西省固体废弃物的综合利用为导向，选取当地典型的拜耳法赤泥（RM）和煤系偏高岭土(CMK)为原料研发制备赤泥-煤系偏高岭土地聚合物，围绕“地聚合物的物理力学特性及相关机理研究、地聚合物在酸性环境下的腐蚀行为与劣化机理、纤维增韧地聚合物的力学性能与收缩特性、地聚合物混凝土设计制备及基本力学性能”四个方面展开系统研究。首先，研究了Si/Al、CMK掺量、Na/Al对赤泥-煤系偏高岭土地聚合物物理力学特性的影响，分析了以上因素对地聚合物相关性能的作用效应及机理，提出了基于原子摩尔比的强度调控理论和方法；在此基础上，探究了赤泥-煤系偏高岭土地聚合物在硫酸和盐酸条件下的损伤机理，通过电化学阻抗谱测试，建立了酸性环境下该类地聚合物的等效电路模型，为赤泥-煤系偏高岭土地聚合物在腐蚀环境中的长期耐久性提供了理论依据及无损检测手段；基于复合材料理论，评估了纤维种类、掺量、长度对赤泥-煤系偏高岭土地聚合物的增韧与减小干燥收缩效果，并提出适用于纤维地聚合物的收缩预测模型。此外，扩展研发了以赤泥-煤系偏高岭土地聚合物为胶凝材料的混凝土，采用四因素四水平的正交设计方法，研究了地聚合物混凝土的基本物理力学特性以及微观结构。