不同产地蓝铜矿矿物学及谱学特征研究

Mineralogical and Spectral Characteristics of Azurite Ores From Different Origins

蓝铜矿是含铜的碳酸盐矿物,它产于铜矿床的氧化带,是一种次生矿物,因此蓝铜矿的出现可作为寻找原生铜矿床的标志。国内学者对蓝铜矿的谱学研究比较少,且对世界不同著名产地蓝铜矿矿物学与谱学特征对比是空白区。通过扫描电镜能谱分析仪、粉晶X射线衍射仪、同步热分析仪、红外光谱仪等仪器对2块中国产地蓝铜矿矿物样品(安徽六峰山、广东阳春)与2块外国产地蓝铜矿矿物样品(老挝、澳大利亚)的成分、结构及谱学特征进行了分析与探讨。能谱元素分析结果显示4块矿物样品的主要元素为C、O、Cu三种元素。X衍射结果表明除产于安徽六峰山矿物外,其他3种产地矿物X衍射物相分析结果均为蓝铜矿Cu_(3)(OH)_(2)(CO_(3))_(2)。产于安徽六峰山矿物除了主物相蓝铜矿的衍射峰外,在其他位置也检测出衍射峰,表明产于安徽六峰山的矿物含有第二物相孔雀石CuCO_(3)·Cu(OH)_(2)。从同步热分析仪热重曲线可以看出主要有两个失重台阶,300℃之前的失重可能是蓝铜矿中含有小部分的孔雀石的分解失重,而300~600℃的失重对应的是蓝铜矿的分解失重。从红外光谱上看主要的红外峰为蓝铜矿的特征峰,四个不同产地的红外光谱比较相似。结合蓝铜矿的外观特征,可为不同产地蓝铜矿的产地鉴定和检测提供依据。

Azurite is a copper-containing carbonate mineral that occurs in the oxidation zone of copper deposits.It is a secondary mineral,and its presence can serve as an indicator for searching primary copper deposits.There is relatively little spectroscopic research on azurite by domestic scholars,and the comparison of mineralogical and spectroscopic characteristics of azurite from different famous locations worldwide is an area that has not been explored.In this paper,the composition,structure,and spectroscopic characteristics of two samples of azurite from China(Liufengshan,Anhui;Yangchun,Guangdong)and two samples from foreign locations(Vietnam,Australia)were analyzed and discussed using scanning electron microscopes(SEM),X-ray diffraction(XRD),simultaneous thermal analysis(STA)and Fourier transform infrared spectrometer(FTIR).The energy dispersive elemental analysis results show that the main elements in all four mineral samples are C,O,and Cu.X-ray diffraction results indicate that,except for the sample from Liufengshan,Anhui,the X-ray diffraction phase analysis of the other three samples from different locations correspond to azurite Cu_(3)(OH)_(2)(CO_(3))_(2).In addition to the diffraction peaks of the main phase azurite,diffraction peaks were also detected at other positions in the sample from Liufengshan,Anhui,indicating the presence of the second phase malachite CuCO_(3)·Cu(OH)_(2)in the sample.From the thermal analysis curve obtained from synchronous thermal analysis,it can be observed that there are mainly two weight loss stages.The weight loss before 300℃may be attributed to the decomposition of a small amount of malachite in azurite,while the weight loss between 300℃and 600℃corresponds to the decomposition of azurite.The main infrared peaks observed in the infrared spectra are characteristic peaks of azurite,and the infrared spectra from the four different locations are relatively similar.Combined with the visual characteristics of azurite,this study can provide a basis for identifying and detecting azurite from different locations.