水玻璃固化黏土矿物的试验研究

Experimental study of clay minerals solidified by sodium silicate

采用扫描电镜(SEM)、X线衍射(XRD)和X线光电子能谱(XPS),对常温下不同密度水玻璃固化的蒙脱石、伊利石和高岭石试样进行测试与分析。结果表明:黏土矿物由固化前的粒状、片状结构转变为固化后的团块状的网状结构。黏土矿物固化样中出现明显的非晶态弥散峰群,未出现新的晶体;固化样衍射强度变小、晶层间距变小、颗粒变得更细小,结晶构造有序性变差,但晶体主体依然是黏土矿物的晶体。固化样中,仅1.15 g/cm3水玻璃固化的蒙脱石样的Ca-2p电子结合能减少了0.624 6 eV,其余元素的相应值未变化。水玻璃固化黏土矿物的机理是:硅酸盐离子和硅酸胶粒在黏土矿物表面如蒙脱石的晶层平面与端面存在复杂的吸附作用,形成了团粒,具有很大表面能的团粒进一步失水缩聚,形成非晶质硅酸盐凝胶和晶质黏土矿物共存的网状结构产物,限制了黏土矿物的活性,固化了黏土矿物。

Such clay minerals as montmorillonite and illite and kaolinite solidified by two different density sodium silicate under room temperature were tested and analyzed by carrying out X-ray diffraction（XRD）,scanning electron microscope（SEM） and X-ray photoelectron spectroscopy（XPS）.The results show that the microstructure of solidified clay minerals is changed from granular and sheet formation to block net formation.There are amorphous dispersing diffraction peaks and no new crystals in the samples of solidified clay minerals.Diffraction intensity and lattice spacing of solidified clay minerals become smaller,and mineral particles become finer,and orderliness of crystal structure become worse.In all the elements of samples,only Ca-2P electron binding energy of montmorillonite solidified by sodium silicate with density 1.15 g/cm3 decreases 0.624 6 eV.The findings indicate the mechanism of clay minerals solidified by sodium silicate.Because of complicated adsorption of such clay minerals surface as crystal layers and edges,aggregate is formed by silicate ions and silica gel particles.The net structure products of amorphous silicates gels and crystalline clay minerals are generated in the process of aggregate dehydrating.These silicate gels restrain clay minerals activities and make clay minerals solidified.