机械粉磨对黄河泥沙颗粒群特性及胶凝活性的影响

Influence of Mechanical Grinding on the Particle Groups Characteristics and Cementitious Activity of Yellow River Sediment

通过机械粉磨对黄河泥沙进行活性激发,研究了随着机械粉磨时间的延长,泥沙颗粒群特性和胶凝活性的变化,从颗粒群粒径分布变化、矿物组成、晶体结构等方面表征了其性能的变化且阐释了活化机理,并利用灰色关联度分析定量化表征颗粒群粒径分布的变化与活性指数的内在联系。活性指数随着机械粉磨时间的延长先增大后减小,其中机械粉磨40 min时,泥沙活性指数最高,3 d、7 d、28 d分别为53.9%、67.6%、84.7%。在机械粉磨40 min内,颗粒粒径变化幅度较高,超过40 min后粒径变化幅度较小。泥沙粒径分布中,小于20μm的颗粒对活性指数起增强作用;大于20μm的颗粒对活性指数起劣化作用;10~20μm粒径范围内颗粒含量的波动对活性指数的影响最大。经机械粉磨后,泥沙矿物晶体的衍射峰半高宽增大,晶粒尺寸减小,晶体的结晶度显著下降,这些晶体结构参数的变化是泥沙活性指数提高的内在因素。

In this work,Yellow River sediment was activated by mechanical grinding.The changes in particle groups characteristics and cementitious activity of the sediment with increasing grinding time were investigated.The changes in particle size distribution,mineral composition and crystal structure were characterized to explain the mechanism of mechanical activation,and the intrinsic relationship between variations in particle size distribution and activity index was expressed quantitatively using gray correlation analysis.The activity index increased and then decreased with the increase of mechanical grinding time,and the highest activity index at 40 min was 53.9%,67.6%and 84.7%for 3 d,7 d and 28 d,respectively.Within 40 min,the reduction of particle size was higher,and the decrease of particles was smaller after more than 40 min.In the particle size distribution of the sediment,particles smaller than 20μm played an enhancing role on the activity index;particles larger than 20μm played a deteriorating role on the activity index;the variation of particle content in the particle size range of 10—20μm exhibited the greatest influence on the activity index.After mechanical milling,the half-height width of the diffraction peaks increased,the grain size decreased,and the crystallinity of the mineral crystals decreased significantly.These changes in crystal structure parameters were intrinsic factors for the increase of activity index.