电渗作用下高岭土的元素及矿物成分变化

Effects of electroosmosis on variation of elemental and mineral composition of kaolin

为研究电渗对土的化学成分及矿物的影响,以高岭土为试样进行室内电渗固结试验。取一维电渗固结试验前后的土样及排出水样,采用X射线衍射及X射线荧光光谱分析测定土样的矿物组成及化学成分,通过ICP-MS测定水样的化学成分。土样及排出水的化学成分变化以及电渗过程中不同元素的迁移现象表明:高岭土的主要矿物成分中,地开石含量的变化幅度较大,而石英、高岭石、珍珠陶土的变化幅度很小;土体的主要化学成分SiO_2、Al_2O_3经过电渗作用后没有明显变化,变化幅度较大的化学成分为CaO、MgO、Na_2O、K_2O,其中CaO的变化明显强于其他成分;Na、K容易以离子形式发生迁移流入水中,Ca、Mg则反应生成氢氧化物沉淀而不易被检测出来,表现为"消失"。

In order to investigate the effects of electroosmosis on chemical and mineral compositions of soil, a laboratory electroosmotic consolidation test was carried out using kaolin as an example. The soil samples and drainage water samples before and after the one-dimensional electroosmotic consolidation experiment were collected. The mineral and chemical composition of soil samples were measured using the X-ray diffraction and X-ray fluorescence spectrometry techniques, and the chemical composition of the water samples were measured with inductively coupled plasma mass spectrometry （ICP-MS）. The variations of chemical composition in the soil and water samples and the migration phenomenon of different elements during the electroosmosis process were analyzed. The results show that, of the main mineral constituents of kaolin, the dickite content changed significantly, while the quartz, kaolinite, and nacrite contents changed little. The main chemical constituents in the soil samples, SiO2 and Al2 O3 , did not show obvious change after electroosmosis. There were large changes in CaO, MgO, Na2 O, and K2 O, of which the variation of CaO was the most significant. The analysis of water samples shows that Na and K tended to flow into water in the form of ions, and Ca and Mg tended to generate hydroxide precipitation, which meant that the Ca and Mg ions could not be detected easily.