不同氯盐溶液中钙矾石与氯离子结合的研究

Combination of Ettringite and Chloride Ion in Different Chloride Solutions

通过溶液法合成钙矾石(AFt),然后采用X射线衍射(XRD)、热分析(TG-DSC)和红外光谱(IR),对比研究了NaCl溶液和模拟海水溶液对AFt与氯离子结合的影响.结果表明:在纯NaCl溶液中,未发生AFt与氯离子的化学结合;当模拟海水溶液中氯离子的浓度升至0.270 mol/L时,有少量Friedel盐形成,同时AFt衍射特征峰的位置发生偏移;当模拟海水溶液中氯离子的浓度升至0.540、1.700 mol/L时,AFt的衍射特征峰消失,水化产物主要为CaSO_(4)·2H_(2)O及Friedel盐;AFt对氯离子的结合在纯NaCl溶液中主要为物理吸附,在模拟海水溶液中不仅有物理吸附,还有化学结合.

The ettringite was synthesized in solution. The effects of chloride ion concentration and liquid phase composition on the curing of ettringite were studied through X-ray diffraction(XRD),thermal analysis(TG-DSC)and infrared spectroscopy(IR). The results show that there is no ettringite adsorb chlorine ions in pure sodium chloride solution. In the simulated seawater solution,when the concentration of chloride ion is up to 0.270 mol/L,a small amount of Friedel’s salt is started. At the same time,the position of ettringite diffraction peak is shifted. When the concentration of chloride ion rises to 0.540 mol/L and 1.700 mol/L,the characteristic peak of ettringite diffraction is basically disappeared,and the hydration products are mainly gypsum and Friedel’s salt. In pure sodium chloride solution,the main binding mechanism of ettringite to chloride ion is physical adsorption. In the simulated seawater solution,the binding mechanism of ettringite to chloride ion is not only physical adsorption,but also chemical binding.