废弃玻璃粉反应析晶制备玻璃陶瓷过程中硅酸盐晶体多体转变与调控

The traditional production model of glass-ceramics has been a "one-to-one", that is to say, in order to obtain a desired glass-ceramic, must first be prepared by melting a batch of parent glass with the specific components. Explore the "one-to-multiple" preparation model of glass-ceramics by directly reactive crystallization of common soda-lime glass and added crystal become new research method. Applicant has proposed a novel route, sintering-reactive crystallization, to fabricate a series of different types of glass-ceramics using the waste soda-lime glass powder as main raw material by adding different silicate crystals into glass powder and then sintering, which the fluoramphibole glass-ceramics can widely application in environmental protection building materials, because it possesses good machinability. This technique make against mass and low-cost production without melting glass with the specific components and can significantly reduce the sintering temperature and energy consumption. The changes of anion group unit of Si-O tetrahedron and fine microstructure of silicate crystals, the crystallization enthalpy, the relationship between crystallinity and thermal process and the active energy and rate equation of reactive crystallization from start to finish of reactive crystallization will be experimentally researched and the internal transformation route of silicate crystals will be explored based on the theories of thermodynamics, dynamics and mineral polysomy. The aim of the study is to model a polysomatic transformation of silicate crystals and to forecast the type of crystal formed by reactive crystallization according to the above model, achieve the controllable preparation of different kinds of glass-ceramic and lay a solid theoretical foundation and feasible practical way for the application of glass-ceramics prepared by reactive crystallization using the waste glass powder.

在传统玻璃陶瓷的生产模式中，一种玻璃陶瓷需熔制一种特定组分的母相玻璃，而通过普通钠钙玻璃外加晶体直接反应析晶制备玻璃陶瓷是一种新的一对多的制备方法。申请者以废弃玻璃粉为主要原料，加入不同硅酸盐晶体反应析晶制备出一系列不同类型的玻璃陶瓷，其中氟闪石玻璃陶瓷具有良好的可加工性，可作为绿色环保建材应用。该工艺无需熔制特定组分的玻璃，能显著降低烧结温度，减少能耗，利于大批量低成本生产。本项目通过研究硅氧四面体阴离子团精细结构的变化、析晶热、析晶量与热处理工艺的关系、反应析晶活化能及反应析晶速率方程，运用析晶热力学、动力学与矿物多体理论，探讨晶体转变规律，目标是建立硅酸盐晶体多体转变模型及通过模型预测外加晶体反应析晶生成新晶体的类型，实现不同种类玻璃陶瓷的可控制备，从而为废弃玻璃粉反应析晶制备玻璃陶瓷的推广应用提供坚实的理论基础和切实可行的实际途径。

反应析晶法制备玻璃陶瓷不仅简化了玻璃陶瓷的制备工艺，降低了生产成本，还能对废玻璃回收利用，是一项极有潜力的制备玻璃陶瓷的新工艺。与传统的熔融法和烧结法不同的是，玻璃陶瓷中的晶体不是从母相玻璃中析出，而是在烧结过程中通过析晶促进剂和玻璃间的反应析出。本项目通过研究反应析晶的工艺参数，运用析晶热力学与矿物多体理论，探讨晶体转变规律，目标是建立硅酸盐晶体多体转变模型及通过模型预测外加晶体反应析晶生成新晶体的类型，实现不同种类玻璃陶瓷的可控制备。本项目的主要研究内容和成果包括：1. 确定硅灰石、氟闪石、透辉石玻璃陶瓷的反应析晶温度，对反应析晶机理、反应析晶影响因素、玻璃陶瓷组织和性能间的关系以及工艺参数对玻璃陶瓷性能的影响进行了系统研究；研究表明，析晶促进剂加入量为30%、烧结温度900ºC、保温时间2h时均可获得较好的析晶效果；2. 对烧结过程中外加晶体/玻璃界面反应和两者间的成分扩散进行了研究；在晶体反应析出阶段，玻璃中的O2-、Ca2+、Si4+等通过扩散进入促进剂晶体中，使促进剂晶体中硅氧四面体平面网断裂形成硅氧四面体双链，导致促进剂晶体转变成玻璃陶瓷目标晶核；同时K+、Mg2+、Al3+等元素从促进剂晶体向其周围玻璃中扩散促使玻璃的无规网络结构断开，导致玻璃中的硅氧四面体以链状形式反应析晶；3. 建立了钙铝黄长石-硅灰石、氟云母-氟闪石、顽辉石-透辉石转变的晶体学模型；对反应析晶过程的热力学进行研究；4.使用尖晶石、莫来石、钾霞石作为析晶促进剂制备玻璃陶瓷从而对硅酸盐晶体多体转变模型进行验证。结果表明，不同析晶促进剂发生扩散的离子不同，从而影响了玻璃陶瓷中的玻璃含量，进而导致晶体中Si/O摩尔比发生变化，获得不同析晶产物。5. 在制备硅灰石、氟闪石、透辉石玻璃陶瓷的基础上进行了彩色玻璃陶瓷的研究，其性能达到了建筑用微晶玻璃的标准。该研究对于废弃玻璃粉反应析晶制备玻璃陶瓷具有重要的参考价值。