水玻璃粘结剂改性技术的现状及发展趋势

Present Situation and Development Trend of Sodium Silicate Binder Modification Technique

结合酯硬化水玻璃砂应用特点,介绍了水玻璃粘结剂改性技术的现状及发展方向。水玻璃粘结剂改性的本质可概括为提高纯净度(降低杂质含量)、减少老化现象(加入抗老化物质)、提高水玻璃砂的强度、溃散性、抗湿性、操作性等。水玻璃的模数是水玻璃砂性能的主要性能控制指标,调整水玻璃的模数是调整水玻璃砂硬化速度和强度的主要手段。普通干法再生砂能实现循环使用的关键技术之一是采用模数为1.6～2.0的超低模数的水玻璃。目前,水玻璃砂的抗湿性问题、干法再生砂循环使用后溃散性快速恶化问题、酯硬化水玻璃砂厚大砂型的硬透性问题等还有待进一步解决,这些问题的深入研究及其实用技术的开发是水玻璃粘结剂改性技术的发展方向。

Combining with discussion on the application characteristics of the ester-hardened sodium silicate sand, the present situation and development trend of the sodium silicate binder modifying technique was introduced. The essence of the sodium silicate binder modifying technique can be summarized as： to enhance the purity, i.e. to reduce the impurity content, to decrease aging degree by adding aging resistant materials, to improve some special properties such as to increase the bonding strength, to improve collapsibility, moisture-resistance as well as the workability, and so on. The modulus of the sodium silicate is the main parameter to control properties of the sodium silicate sand, and the modulus adjusting is the main means to adjust the sand hardening speed and the sand strength after being hardened. One of the processes to realize the recycling usage of the ordinary dry reclaimed sand is to adopt the sodium silicate with extra-low modulus of 1.6 -2.0. At present, some problems with sodium silicate sand still remain to be solved such as the problems with moisture resistance of the sodium silicate sand, the collapsibility rapid deterioration of the dry-reclaimed sand after recycling usage, thorough hardening of the ester-hardened sodium silicate sand mold/core with heavy section, etc. Therefore, the further investigation and the development of practical techniques to solve these problems became the development trend of the sodium silicate binder modifying technique.