西藏班戈湖水菱镁矿矿物学研究

Study on mineralogy of hydromagnesite from Bangor Lake in Tibet,China

为了研究西藏班戈湖地区水菱镁矿的形态、矿石化学成分及矿物组成、主要矿物共生关系及典型特征,采用偏光显微镜、扫描电子显微镜、透射电子显微镜、电子探针及MLA矿物分析检测系统进行分析。结果表明:水菱镁矿为土块状隐晶质集合体,结晶颗粒非常细小,单体呈单斜板片状,在(001)晶面具有特征倾斜条纹,易发育成具有层状结构的聚片双晶及沿(100)晶面的接触双晶。在水菱镁矿的矿石中,常见文石、白云石等碳酸盐矿物,并常与其呈浸染状共生关系,相互之间分离难度较大。

In order to study the morphology,chemical composition,symbiotic relationship among major minerals and the typical embedding characteristics of the hydromagnesite from Bangor Lake in Tibet,polarizing microscope,scanning electron microscope,transmission electron microscope,electron probe and MLA mineral analysis system were used. The results indicate that the hydromagnesite is cryptocrystalline aggregate which consists of small crystal particles. The single crystal which has characteristic striation on the(001) is monoclinic plate-like. The hydromagnesite crystal usually grow into layered polysynthetic twin and contact twin along(100). Aragonite,dolomite and other carbonate minerals are often associated with hydromagnesite in disseminated symbiotic relationship in raw ores. It might be difficult to use physical mineral processing to get rid of them.