摘要
通过缓慢分解 Ca2 + - Mg2 + - HCO-3 - Cl-- H2 O溶液和以菱锶矿 (或碳钡矿、白铅矿 )为晶种的附晶生长法 ,在 0— 90℃温度范围内定向合成了碳酸钙同质多象变体。矿物合成实验结果表明 ,随着温度升高 ,有利于亚稳态文石和不稳定六方方解石的生成 ;随着溶液中Mg2 +离子浓度增大和 Ca(HCO3 ) 3 溶液浓度减小 ,均有利于亚稳态文石的形成。以 XRD和SEM技术为实验手段 ,详细研究了碳酸钙同质多象转变过程。结果显示 :在流体参与的情况下 ,文石→方解石和六方方解石→方解石的同质多象转变速率很快 ,并且其转变的矿物学机理为溶解 /再沉淀。
Polymorphs of calcium carbonate were orientedly synthesized in a temperature range 0—90 ℃ by techniques of the slow decomposition of Ca 2+ Mg 2+ HCO - 3 Cl - H 2O solution and the overgrowth with SrCO 3, BaCO 3 or PbCO 3 as seed crystals. The results suggest that an increase in experimental temperature is favorable to the formation of metastable aragonite and unstable vaterite, and that an increase in Mg 2+ concentration or a decrease in Ca(HCO 3) 2 solution concentration favors the formation of aragonite. The processes and mineralogical mechanisms of polymorphic transformation from aragonite to calcite and from vaterite to calcite were investigated by means of XRD and SEM techniques. The results indicate that the rates of polymorphic transformation from aragonite to calcite and from vaterite to calcite are very fast, and that their mineralogical mechanisms of polymorphic transformation are dissolution reprecipitation.
出处
《地质科学》
CAS
CSCD
北大核心
2000年第3期325-335,共11页
Chinese Journal of Geology(Scientia Geologica Sinica)
基金
国家自然科学基金! (编号 4 990 30 0 1和 4 94 530 0 3)
中国科学院专项基金
关键词
碳酸钙
矿物合成
同质多象转变
矿物学机理
Calcium carbonate, Mineral synthesis, Polymorphic transformation, Mineralogical mechanism
