机械力化学改性钙基膨润土提高注浆材料的稳定性

Mechano-Chemical Modified Calcium Bentonite Improves Stability of Grouting Materials

利用高能球磨机,通过机械力作用和机械力化学作用分别对钙基膨润土进行改性,通过X射线衍射仪、扫描电子显微镜、激光粒度仪及Zeta电位仪对改性膨润土进行表征,然后将经机械力作用和机械力化学作用改性的膨润土分别加入水胶比为1的水泥浆。结果表明:经机械力化学作用改性后,膨润土的d(001)由未改性的1.52 nm变化为1.27 nm,其层间钙离子被钠离子置换,D50(样品颗粒累计50%点的直径)由未改性的13.5μm降低到0.64μm,Zeta电位由未改性的-5.5 mV变为-66.3 mV,可达到粒度减小和表面改性的双重目的。经球磨机研磨45 min后的膨润土可使水泥浆静置2 h的泌水率降低至3.97%,将焦磷酸钠与膨润土湿磨15 min后复合物可使水泥浆的泌水率降低至3.64%。

Modification of calcium bentonite by mechanical and mechano-chemical chemistry using a high energy ball mill.The structure and properties of modified muscovites were characterized by X-ray diffractometer,scanning electron microscopy,laser scattering analysis and Zeta potential analyzer,respectively.Then the bentonite modified by mechanical force and the bentonite modified by mechano-chemical force were respectively added to the cement slurry with a water-to-binder ratio of 1.The results show that after mechano-chemical modification,d(001)is changed from 1.52 nm to 1.27 nm,and the calcium ions between the layers of bentonite are replaced by sodium ions,D 50 decreases from unmodified 13.5μm to 0.64μm,the zeta potential changes from unmodified-5.5 mV to-66.3 mV,which can achieve the dual purposes of particle size reduction and surface modification.After 45 minutes of grinding by high-energy ball mill,the bentonite can make the cement slurry stand for 2 h and the bleeding rate reaches 3.97%.The bentonite after wet grinding of sodium pyrophosphate and bentonite for 15 minutes can make the bleeding rate of the cement slurry reach 3.64%.