温度-浓度耦合作用下可溶岩钙芒硝溶浸细观结构演化

岩石细观结构通常随外部环境变化而逐渐发展演化,为了研究不同溶浸条件下钙芒硝细观结构演化的规律。通过对特殊的钙芒硝可溶岩在不同温度与浓度溶液中溶蚀过程进行显微CT观测,以孔隙率为表征参数,研究了不同温度、不同浓度盐溶液中,4 mm×4 mm×9 mm长方体试样同一截面的孔隙结构演化特征。试验结果表明,各种条件下钙芒硝均由表及里进行溶解,孔隙发展具有明显的渐进过程;3种浓度条件下,钙芒硝在淡水中的溶浸速度及细观结构演化最快,孔隙率随时间呈线性规律急速增大。在常温淡水溶液中溶浸48 h后,钙芒硝的孔隙率较初始孔隙率增大近10倍,而在半饱和与饱和盐溶液中仅增大1~2倍。不同温度条件下,95℃溶液比常温溶液作用下钙芒硝孔隙率演化速率提高了4~5倍。溶浸作用下钙芒硝可溶岩孔隙率演化存在显著温度与浓度效应。

Micro- structural development of glauberite under temperature and concentration coupling effect

Rock micro- structure always developed with changing of external circumstances.To investigate the micro- structure the micro- structure development of glauberite under different solutions，serried of experiments were performed with cuboid glauberite specimens in size of 4 mm×4 mm×9 mm，the micro- structure development of the specimens were tested and recorded through a micro- CT system μCT225kVFCB.Through statistic analysis，some characteristics of porosity and pore diameter of glauberite were discovered with concentration and temperature changing of the solutions.The results show that the mineral dissolution of the specimens develops slowly from the outside to the inside，and it is the typical mutual acceleration of dissolution and seepage process.After 48 hours，the porosity of glauberite dissolved in fresh water at RT is almost as tenfold as that of original specimen.However，the porosity of glauberite dissolved in half- saturated and saturated saline solutions only increases one to two times as the original.With solution temperature increasing，the porosity increase rate of glauberite in 95 ℃ solution is improved by 4 to 5 times than room temperature.Temperature and concentration play a significant role on the porosity development of glauberite.