Liaoning Technical University
由于废弃物渗透液中复杂的化学物质能影响钠基膨润土垫层的吸水膨胀性能,针对这种情况本文研究了不同价态及浓度的盐溶液对膨润土膨胀指数的影响,同时探究了pH值及温度对膨润土膨胀性能的影响,利用X射线衍射仪及扫描电子显微镜对盐溶液处理后的膨润土进行表征分析。试验结果表明,高价态高浓度的盐溶液对膨润土的膨胀性能起抑制作用,此时膨胀指数最低为5 mL/2g,单价态低浓度的NaCl溶液对膨润土的膨胀性能起促进作用,此时膨胀指数达到最高达到56mL/2g。XRD测试表明盐溶液处理后的膨润土层间距由12.512?下降到11.856 ?,SEM测试分析发现在高价态盐溶液中膨润土形貌由规则鳞片状转化为无规则絮凝状。在给定盐溶液浓度为0.04mol/L、pH值为9及温度为90℃的条件下,膨胀指数提升近50％。膨润土吸水膨胀过程中凝胶态部分符合non-Fickian扩散模型,水分子扩散速率与膨润土凝胶态部分松弛速率大致相同。
Since the complex chemical substances in the waste permeate can affect the water-absorbing swelling performance of the sodium bentonite cushion, this paper studies the influence of different valences and concentrations of salt solutions on the swelling index of bentonite, At the same time, the influence of pH and temperature on the swelling performance of bentonite was explored, and the bentonite treated with salt solution was characterized and analyzed by X-ray diffractometer and scanning electron microscope. The test results show that the high-valence and high-concentration salt solution inhibits the swelling performance of bentonite, and the swelling index is at least 5 mL/2g, The monovalent low-concentration NaCl solution promotes the swelling performance of bentonite, and the swelling index reaches a maximum of 56mL/2g. XRD test showed that the bentonite layer spacing after salt solution treatment decreased from 12.512 ? to 11.856 ?. SEM test analysis found that the morphology of bentonite in the high-valence salt solution changed from regular scaly to irregular flocculation. Under the conditions of a given salt solution concentration of 0.04 mol/L, a pH value of 9 and a temperature of 90°C, the expansion index increases by nearly 50%. The gel part of bentonite swells in accordance with the non-Fickian diffusion model, and the diffusion rate of water molecules is roughly the same as the relaxation rate of the gel part of bentonite.