天然及合成的硅灰石的高压研究

 研究了天然硅灰石（CaSiO₃）的压致相变，并采用高温高压方法直接合成了硅灰石。结果表明：天然硅灰石经高压（4.6~5.0 GPa）高温（1 200~1 250 ℃）处理后转变为深玫瑰色半透明立方晶体，而采用高温（1 050~1 100 ℃）高压（3.8~4.3 GPa）直接合成的硅灰石也具有同样结构及形貌。SEM分析表明：天然硅灰石SiO₂及CaO的含量分别为50.8%和48.1%，而人工合成的产物SiO₂及CaO含量分别为51.35%和48.15%。

HIGH PRESSURE STUDY ON WOLLASTONITE

The wollastonite (CaSiO₃ ) synthesized by high temperature (HT) under atmospheric pressure (AP) has a triclinic structure while the natural wollastonite with high purity originating from Dading Mountain, Lishu, Jilin Province, China, has a white chain-like structure of monoclinic type. Pressure-induced phase transformation of this natural wollastonite above and the wollastonite synthesized directly from raw materials by HP and HT were firstly investigated. Results show that the natural wollastonite treated under HP (4.6～5.0 GPa) and HT (1 200～1 250 ℃) transforms to partially translucent cubic crystal with dark rose colour and the one synthesized directly by HP (3.8～4.3 GPa) and HT ( 1 050～1 100 ℃)to the same structure and with similar appearance. SEM analysis indicates that, for the natural wollastonite, the contents of SiO₂ and CaO are 50.8% and 48.1% respectively, while the synthetic one, both treated and synthesized directly by HP and HT, has the contents 51.35% and 48.15% respectively.