预处理方法对氯氧镁水泥中自由氯离子溶出的影响

摘要

The influence of drying temperature,crushing method and extraction solvent on leaching of free Cl-are discussed through determining water-soluble or alcohol-soluble Cl-(also as indicators of free Cl-) content in MOC pretreated by different pretreatment methods.The results indicate that the structure of 5Mg(OH)2·MgCl2·8H2O (P5) was partial thermal decomposition when the drying temperature is higher than 80 ℃,which leads to the great increase in the water-soluble and alcohol-soluble Cl-content; P5 is converted into amorphous structure that more easily dissolves into water but difficultly dissolves in absolute ethyl alcohol because of the mechanochemical effect in the grinding process,and absolute ethyl alcohol or water can prevent P5 amorphous transforming during ball milling; the content of Cl-released from P5 by water decomposing is about five times as compared with alcohol-soluble Cl-content in MOC.%以MOC中醇溶性Cl-质量分数作为衡量自由Cl-质量分数的指标,通过测定经不同预处理方法得到的MOC样品中的水溶性或醇溶性Cl-质量分数,分析干燥温度、粉碎方式和萃取溶剂对MOC中自由Cl-溶出的影响.研究结果表明:当干燥温度高于80℃时,因MOC的主要水化产物5Mg(OH)2·MgCl2·8H2O(P5)发生部分热分解使结构破坏,导致水溶性和醇溶性Cl-大幅度增加；粉碎过程中的机械力化学效应使P5在球磨过程中发生非晶化转变,非晶化的P5更易溶于水而难溶于乙醇,用无水乙醇或水作助磨剂能阻止P5的非晶化转变；用水作溶剂时P5被水分解释放出的Cl-质量分数约为MOC中醇溶性Cl-质量分数的5倍.