利用熔融态高炉渣显热直接成形微晶玻璃的基础研究

The technologies for manunfactering glass-ceramics produced with the blast furnace (BF) slag as main raw materials have been developed for many years. However, the research and application of BF slag glass-ceramics are restricted because of the high energy consumption and production cost. How to efficiently use the sensible heat of BF slag is very helpful for saving energy of metallurgy industries.This research aims at manufacturing glass-ceramics with the BF slag as the main materials using sensible heat of liquid BF slag. On the basis of testing chemical composition, mineral constituent and microstructure of BF slag, effect of chemical composition and temperature on viscosity and melting temperature will be studied and the model of “composition-temperature-viscosity” for BF slag will be set up. The diffuse process and disperse characteristic of nucleation agents in liquid BF slag under different temperature will be studied using solution with different viscosity composed by sodium silicate and glycerinum at room temperature. Rational temperature of adding nucleation agents into liquid BF slag could be determined according to these results and nonuniform crystallization could be controlled and even eliminated. The activation energy of devitrification in phase seperation of glass will be calculated and dynamics process of phase seperation in glass will be discussed according to the DTA and IR spectral absorption results. The restrictive factors in crystallization and growth process of BF slag glass-ceramics could be found. The relationship between nucleation agent, heat treating temperature and microstructure, principal crystalline phase will be studied sysmatically. All these results will provide powerful theory support for glass-ceramic manufacturing using the sensible heat of liquid BF slag.

用高炉渣制备微晶玻璃在技术上完全可行，但由于生产成本和能耗高而限制了其发展。高炉渣显热的合理高效利用也一直是钢铁工业节能的重要研究方向，本项目就是充分利用熔融态高炉渣显热一步完成高炉渣微晶玻璃的配料、熔融及制备成形，并研究其相应的晶化机理。在分析高炉渣化学成分、矿物组成、显微结构的基础上，深入研究其他配料、晶核剂和温度对其粘度、熔化性温度的影响，建立高炉渣的“化学成分-温度-粘度”三维体系模型。利用水玻璃和甘油配置不同粘度的溶液，在室温下模拟研究晶核剂在不同温度高炉渣中的扩散过程和分散特征，进而确定晶核剂加入的合理温度区间，解决微晶玻璃产品的晶化不均匀问题。借助差热分析和红外光谱吸收计算和分析玻璃分相的析晶活化能及动力学过程，讨论影响玻璃析晶和长大的限制性环节，研究晶核剂、热处理温度与显微结构和主晶相类型之间的关系，为利用高炉渣显热直接成形微晶玻璃奠定理论基础。

高炉渣是高炉炼铁过程的副产品，目前的处理工艺主要制成水冲渣，然后用于制造水泥等低附加值产品，在此过程中，不仅高炉渣所携带的一次显热不能充分高效利用，而且还要消耗大量水资源，造成明显的一次能源和二次能源浪费。由于化学成分的相似性，利用高炉渣制备高性能微晶玻璃在技术上是完全可行的。因此，本项目基于节能减排的战略背景，提出了利用高温熔融态一步成形微晶玻璃的思路。. 在实验室通过添加纯化学试剂来调制微晶玻璃成分，采用熔融法成功制备出了性能优异的高炉渣微晶玻璃，并运用高温熔体物性测定仪、拉曼光谱仪、高温综合热分析仪、X射线衍射仪、场发射扫描电子显微镜等现代检测分析手段系统研究了晶核剂对微晶玻璃的熔制、基础玻璃结构、形核结晶温度、物相组成和显微结构的影响，阐明了高炉渣微晶玻璃制备过程的析晶动力学，为高炉渣的显热回收及资源综合高效利用奠定了基础。. 研究结果表明，高炉渣微晶玻璃的晶相为透辉石、普通辉石和钙镁黄长石。随着CaO/SiO2的增加，微晶玻璃中钙镁黄长石的含量增加，微晶玻璃的吸水率升高，耐酸碱腐蚀性能降低。在添加晶核剂TiO2和CaF2的微晶玻璃中，Ti4+能够置换硅氧四面体中的Si4+，F-可以置换O2-，从而破坏硅氧四面体结构，降低玻璃液粘度，有利于玻璃的熔制并增加基础玻璃的不稳定性；在热处理过程中，钛和氟从玻璃基体中析出，使基础玻璃分相。添加晶核剂TiO2和CaF2能够降低微晶玻璃的形核析晶温度，促进微晶玻璃析晶。当TiO2含量为4%时，微晶玻璃晶体含量高、晶粒细小并且排列致密。当CaF2含量大于4%时，微晶玻璃中会生成新晶相—枪晶石；当CaF2添加量为6%时，微晶玻璃晶粒平均粒度为100nm，具有良好的耐酸碱腐蚀性能。