天青石形貌特征的水热晶体生长实验研究  

Experimental study on the morphological characteristics of celestite crystals by using hydrothermal synthesis methods

作　　者：王丽[1,2] 周丽 王春垚 周文戈[3] WANG Li;ZHOU Li;WANG Chun-yao;ZHOU Wen-ge(School of Geography and Environmental Science,Guizhou Normal University,Guiyang 550025,China;State Key Laboratory Incubation Base for Karst Mountain Ecology Environment of Guizhou Province,Guiyang 550025,China;Key Laboratory of High-Temperature and High-Pressure Study of the Earth's Interior,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China)

机构地区：[1]贵州师范大学地理与环境科学学院,贵阳550025 [2]贵州省喀斯特山地生态环境国家重点实验室培育基地,贵阳550025 [3]中国科学院地球化学研究所,地球内部物质高温高压院重点实验室,贵阳550081

出　　处：《矿物岩石地球化学通报》2023年第1期89-97,共9页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金资助项目(91962168)。

摘　　要：为了更好地了解天青石晶体的形貌特征和沉淀机制,本文利用硫酸钠溶液和氯化锶溶液,采用室温混合-室温生长法、室温混合-高温熟化生长法及高温原位混合法,开展了天青石的水热晶体生长实验。结果表明,温度对天青石晶体的形貌具有重要影响。200℃条件下原位混合实验合成的天青石具有多种形貌,包括粒状、X形、V形、片状、树枝状和菱形体,而室温混合-室温生长与室温混合-高温熟化生长实验合成的天青石晶体形貌差异不大,主要为板状和双锥状。此外,树枝状天青石仅出现在200℃条件下[SO_(4)^(2-)]∶[Sr^(2+)]的摩尔比为2∶8和3∶7的高温原位合成实验中,这与前人发现的树枝状重晶石仅出现在Ba^(2+)相对于SO_(4)^(2-)过量的高温原位混合实验的结果相似。可见树枝状形貌可能是重晶石-天青石类质同象固溶体系列矿物的重要形貌标型特征,指示着高温下阳离子相对于阴离子过量的流体混合作用。In order to better understand the morphological features and precipitation mechanism of celestite crystals, in this paper, sodium sulfate solution and strontium chloride solution were used to conduct the hydrothermal synthesis experiments of celestite using various methods including the room temperature mixing-room temperature growth method, the room temperature mixing-high temperature ripening growth method, and the high temperature in-situ mixing method.Results show that the temperature has a significant impact on the morphology of celestite crystal. The celestite crystals synthesized by using the in-situ mixing experiments at 200 ℃ are characterized with various kinds of morphological crystals, including granular, X-shaped, V-shaped, flake-like, dendritic and rhombohedral ones, while the celestite crystals synthesized by using the room-temperature mixing-room-temperature growth and the room-temperature mixing-high-temperature ripening growth experiments, have mainly plate and bipyramid morphologies with little difference. In addition, dendritic celestite crystals were only appeared in the high-temperature in situ synthesis experiments under conditions of [SO_(4)^(2-)]∶[Sr^(2+)] molar concentration ratios of 2∶8 and 3∶7 at 200 ℃. These results are similar to previous experimental results of barite, that is, the dendritic barite only formed in the high-temperature in situ mixing experiments with the mixed solution having excessive Ba^(2+)relative to SO_(4)^(2-)in terms of their molar concentrations. Taken together, dendritic morphology of cystal may be an important morphological feature for minerals of the barite-celestite-like isomorphic solid solution series. This reveals the fluid mixing of excessive cation relative to anion in terms of their molar concentrations at high temperature.

关 键 词：天青石 晶体形貌 标型特征 高温原位混合 水热合成 

分 类 号：P589[天文地球—岩石学]