酯硬化水玻璃旧砂中残留酯的提取与测定

Extraction and Determination of Residual Ester for Ester Hardening Sodium Silicate Used Sand

酯硬化水玻璃旧砂及再生砂中的残留酯对再生砂的可使用性能有重要影响。本文旨在建立一种水玻璃旧砂及再生砂中的残留酯提取和检测方法。以乙醇、石油醚、丙酮等为溶剂,采用索氏提取器提取酯硬化水玻璃旧砂中残留酯,将提取物中的残留酯水解后,利用中和滴定法测定其中酸含量。通过酸碱滴定测试残留酯水解产物有机酸的量来反应残留酯的含量。结果表明,通过对提取溶剂、提取温度、提取时间、液固比的研究,在单因素试验基础上采用四因素三水平正交试验对提取条件进行优选,确定了最佳提取工艺:提取溶剂为石油醚,提取温度为80℃,提取时间1.5 h。这为水玻璃再生砂性能的评价奠定基础。

Residual ester of the ester hardening sodium silicate used sand and reclaimed sand has important influence on the workability of the reclaimed sand. The purpose of this paper is to establish a kind of ester extraction and determination method for the residual ester of sodium silicate sand and reclaimed sand. With the solvent such as ethanol, petroleum ether and acetone, soxhlet extractor was used to extract residual ester in the ester hardening sodium silicate sand; after hydrolysis of the extract residual ester, neutralization titration method has been applied to the determination of acid content. Organic acids quantity of hydrolysis product determined by acid-base titration test was used to reflect the content of residual ester. The results show that through the study on the extraction solvent, extraction temperature, extraction time and solid-liquid ratio and on the basis of single factor experiment, four factors and three levels orthogonal experiments were made to optimize extraction conditions and determine the best extraction technology, namely for petroleum ether extraction solvent, extraction temperature is 80 ℃, extracting time 1.5 h, which lays a foundation for the reclaimed performance evaluation of sodium silicate sand.