方解石颗粒尺寸对白云质灰岩中碱白云石反应的影响

Influence of Particle Size of Calcite on Alkali-dolomite Reaction of Dolomitic Limestone

探讨了白云质灰岩中方解石基质对Na^+在岩石中迁移及其对碱白云石反应的影响。采用图像分析法测定不同白云质灰岩样本中方解石颗粒的尺寸,采用N_2吸附法测定岩石孔径分布,采用火焰光度计测定养护在80℃、1mol/L NaOH溶液中岩石柱内部的Na^+含量,采用X-射线内标法定量分析白云质灰岩中碱白云石反应(ADR)生成的水镁石含量。结果表明,白云质灰岩TS-1、TS-2、GS-2及FHS-1中方解石颗粒中位径分别为4μm、12μm、15μm和33μm;方解石颗粒越小,迁移到岩石内部的Na^+含量越高,岩石中白云石的碱白云石反应程度越高。

The influence of the calcite matrixes on migration of Na^＋ and alkali-dolomite reaction was studied in dolomitic limestone. The sizes of the calcite particles in dolomitic limestones were measured by using microscopic image analysis method. The pore size distribution of dolomitic limestones was measured by using N2-adsorption method. The content of Na ＋ ions in sections of the rock prisms was measured by flame emission spectroscopy. Brucite formed by alkali-dolomite reaction （ ADR） was quantitatively analyzed by XRD in the dolomitic limestones. The results indicate that the median diameters of the calcite in the dolomitic limestones TS-1,TS-2, GS-2 and FHS-1 were 4 （ xm,12 （ xm,15 jjim and 33 jjim, respectively. The smaller the size of calcite particles was, the higher the content of Na ＋ migrated in the rock, the higher the dedolomitization of dolomite in the rock would be.