我国第一个新铊矿物铊明矾的发现与研究

The discovery and study of Lanmuchangite,the First New Thallium Mineral,in China

扼要报道了在我国发现的第一个新铊矿物铊明矾及其主要研究成果。铊明矾是在贵州滥木厂铊 (汞 )矿床富铊矿体氧化带中发现的一个新铊矿物种。与多种次生矿物共生。集合体大小一般为 2 - 10mm ,白色至淡黄色 ,玻璃光泽 ,透明 ,折光率为 1.4 95 ,维氏硬度为 94 -12 4kg/mm2 、摩氏硬度为 3.1- 3.4 ,实测密度 2 .2 2 g/cm3,易溶于水。化学式为 (Tl1.0 0K0 .0 5) 1.0 5(Al1.0 1Si0 .0 2 Ca0 .0 1Mg0 .0 1Fe0 .0 1) 1.0 6[SO4 ]2 .0 2 · 11.86H2 O ,理论式为TlAl[SO4 ]2 ·12H2 O .X射线粉末衍射数据经指标化 ,并参照人工合成TlAl[SO4 ]2 ·12H2 O的资料 ,确定铊明矾为等轴晶系 ,空间群为Pa3,a =12 .2 12 (5 ) 、v =182 1(2 ) 3、Z =4 ,与人工合成物及明矾族的钾明矾、钠明矾和铵明矾为等结构 ,应属明矾族矿物之一 ,其在成分上有别于其他矿物者为一价阳离子为Tl+ .

This is a brief report on the discovery of Lanmuchangite,the first new thallium mineral,in China and the principal results of research on it.The new thallium sulphate mineral was found associated with many secondary minerals in oxidation zone of rich thallium ore bodies in Lanmuchang thallium ore deposit,Xinren county,Guizhou province.The aggregates of Lanmuchangite are 2-10mm in size,white and light yellow in colour,transparent with a glass luster.Their Nmeas=1.495,hvmeas=94-124kg/mm 2,Hm=3.1-3.4,Dmeas=2.22g/cm 3.The mineral is easy to dissolve in water.The empirical formula is (Tl 1.00 K 0.05 ) 1.05 (Al 1.01 Si 0.02 Ca 0.01 Mg 0.01 Fe 0.01 ) 1.06 2.02 11.86H 2O,the simplified fomula is TlAl 2·12H 2O.According to the data of X ray diffration analysis with indexes and information of synthetic TlAl 2·12H 2O for reference,it is determined that Lanmuchangite is characterized by the system(isometric),space group (Pa3),cell parameters (a=12.212(5)?,V=1821(2)? 3,Z=4).The mineral and synthetic TlAl 2·12H 2O and minerals of potassium alum group such as pottasium alum,sodium alum and Tschermigite are in isostructure,and so it belongs to the pottassium alum group,but its composition is different from others in the existence of monovalent thallium (i.e Tl +.)