叶绿矾族矿物是硫化物矿床氧化带的特殊产物,被认为是硫化物矿床的“标志矿物”,分布在氧化带的上部,并与其他高铁硫酸盐共生。特定的地质环境和矿床类型发育有不同的叶绿矾族矿物。新疆哈密红山高硫化物型浅成低温Cu-Au矿床火山机构和次火山岩相控矿作用十分明显,形成于中生代,其成因类型为浅成低温热液型金矿-斑岩铜矿之间过渡的“紫金山式”金铜矿床。其氧化带呈漏斗状产于原生硫化物矿体的上部,延深约50~60m,以硫酸盐矿物为主。利用X射线粉晶衍射、湿法化学和差热分析,在红山氧化带发现了铜叶绿矾、高铁叶绿矾,这两种叶绿矾族矿物均系在中国首次发现。铜叶绿矾湿法化学分析结果为[w(B)/%]H2O 30.87,SO3 36.76,Na2O 0.03,Fe2O3 23.40,CuO 6.27,MgO 0.01,Al2O3 0.01,不溶物0.28,CaO 0.03,总计97.66;其XRD特征谱线为:6.03(100),7.39(95),9.04(65)。高铁叶绿矾湿法化学分析结果为[w(B)/%]:H2O 28.15,SO3 37.02,K2O 3.88,Fe2O3 27.75,Na2O 1.30,MgO 1.86,不溶物0.24,总计100.20;其XRD特征谱线为:9.07(100),6.04(89),5.59(50)。红外和热分析实验进一步验证了化学分析数据的可靠性,并对这些硫酸盐热反应机制和相变过程作了解释。目前该类硫酸盐矿物已作为新型环保资源直接制酸用于湿法炼铜。
The copiapite group minerals are special products of the oxidized zone in a sulfide deposit. These sulfate minerals appear in the middle-upper part of the oxidized zone and coexist with some other high-Fe sulfates. The oxidized zone of the Hongshan HS-epithermal Cu-Au deposit in Hami area of Xinjiang, assuming the filler-like form, lies on the upper part, with a depth of 50-60 m. The authors madea systematic analysis by means of XRD, DAT and TGA and identified various kinds of supergene minerals. The oxidized zone is composed of natural elements, chlorides, Fe-oxides and sulfates in various colors, in which sulfate minerals are dominant. Cuprocopiapite and ferricopiapite were found for the first time in China. Here are the results of XRD and chemical analysis. Chemical analyses of cuprocopiapite ( wB/% ) are H2O 30.87, SO3 36.76, Na2O 0.03, Fe2O3 23.40, CuO 6.27, MgO 0.01, Al2O3 0.01, insoluble residue 0.28, CaO 0.03, and total 97.66, with the characteristic data of XRD analysis being 6.03 (100), 7.39 (95), and 9.04 (65). Chemical analyses of ferricopiapite (wB/%) are H2O 28.15, SO3 37.02, K2O 3.88, Fe2O3 27.75, Na2O 1.30, MgO 1.86, insoluble residue 0.24, and total 100.20, with the characteristic data of XRD analysis being 9.07 (100), 6.04 (89) and 5.59 (50). Furthermore, cuprocopiapite and ferricopiapite were confirmed through the thermal and infrared analysis, and their thermal reaction and facies change mechanism were explained. Now these sulfate minerals have been used as a new type of acid resource for copper smelting. So the researches on the assemblages, modes of occurrence and formation conditions of sulfate minerals in the oxidation zone may help to trace paleoenvironment and paleoelimate.