【作者】 张红雨；

【导师】 苏犁；

【作者基本信息】 中国地质大学(北京) ， 地球化学， 2012， 硕士

【摘要】 硫化物矿物中痕量元素含量变化规律研究已成为近年来矿床学精细研究的重要内容之一。高温、高压封闭酸溶法成为各类地质样品大多数微量元素进行测试的前处理首选方法，但金、银化学性质稳定，且地质样品中其含量较低，测试有一定的难度，以往需要将它们与其他元素分离、充分溶解后才能测定。火试金是经典方法，但火试金存在取样量大、空白值高等缺点。而且无论前述任何一种方法都不能在一次进样分析过程中对微量元素、稀土元素和Au、Ag等元素进行同时检测。本文通过利用中国地质大学（北京）科学研究院元素地球化学实验室的超净化学实验室、Agilent7500a型ICP-MS和与天津一同电子工程设备厂共同研制的高压反应釜，进行了多种溶样方法、稀释倍数、ICP-MS检测条件的对比实验，基本建立了取样量¹00mg、王水-HNO₃+HF-王水二次高压反应釜溶样和2000倍稀释后ICP-MS同时测试黄铁矿等硫化物中微量元素和Au、Ag等贵金属元素的检测、监控方法，利用该方法进行测试的多个标准物质（GSD-11（水系沉积物）、GBW7267（黄铁矿）、GSR-6（泥灰岩）、GSS-5（土壤）和GBW070023（金））测定值与参考值吻合较好，相对误差优于15%，相对标准偏差RSD<5%。测试结果也显示：HNO₃+HF高压反应釜酸溶法保证了除金、银个别元素以外大多数元素的充分溶解以及各标样中所有元素的溶解稳定性；随着王水加入次数（说明王水量和溶解时间增加）的增加，王水对Au和Ag等溶解越充分，王水对其他元素的溶解也未造成明显不良影响；黄铁矿等标样溶解液2000倍稀释可以有效抑制铁的基体效应，也能达到同时准确测定不同含量级别元素的目的。该方法的应用，将有助于更精确地讨论黄铁矿等硫化物结晶条件及伴生Au、Ag等贵金属元素的富集机制。利用该法对大兴安岭三道湾子金矿床精心分选的两个阶段（Ⅰ和Ⅱ期）的黄铁矿中微量和Au、Ag等元素进行了精细分析，测试结果揭示Ⅱ期黄铁矿中Au、Te和Ag的含量普遍高于Ⅰ期黄铁矿，表明Ⅱ期黄铁矿是Te-Au-Ag的重要载体矿物。该研究成果的获得表明微取样量（100mg）、同时、准确测定黄铁矿等硫化物中稀土元素、过渡族元素、大离子亲石元素、高场强元素和Au、Ag等贵金属元素分析方法在相关矿产的成矿机制研究中具有良好的应用前景。更多还原

【Abstract】 Study about trace elements variations in sulfides has been an important part of preciseformation about ore deposit. High temperature and high pressure closure of acid-soluble methodhas become the preferred method of handling the majority of various types of geologicalsamples in analyzing trace elements and REE. It is usually difficult to detect Au and Ag contentsin geological samples for their chemical properties and usually low contents. In order to determineand fully dissolve Au and Ag，we need separate Au and Ag from other elements.The FireAssay method has been the most classic method to take pre-treatment for Au and Ag. The FireAssay method has disadvantages for large amount of sampling and high blank value. However,none of the method mentioned before has the ability to measure trace, rare earth elements togetherwith Au and Ag in one analysis.In this paper, we combined super purified laboratory and Agilent7500a type ICP-MS inChina University of Geosciences Beijing as well as high pressure tax produced by Tianjin Yitongelectronic factory and China University of Geosciences Beijing ICP-MS laboratory to carry outvarious experiments under many solution samples methods, dilution multiples and ICP-MSdetection conditions. We establish basically sulfide （100mg）, aqua regia-HNO₃+HF twice highpressure tax solution samples method and2000times dilution ICP-MS detection way. Applyingthis method, we determined many standard samples including GSD-11（stream sediment）,GBW7267（pyrite）, GSR-6（marl）, GSS-5（soil） and GBW070023（gold）. The results demonstratethat detections of standard coincide well with the given values （RE<15%）and the relative standarddeviations （RSD） are below5%. The results also demonstrate that HNO₃+HF twice high pressuretax solution samples method ensures sucifficent disolutiion of majority elements eacept Au andAg, it also matains the solution stalibity of all elements in standard samples. With increasing timesof aqua regia （indicating increasing contents and dissolved time）, the aqua regia dissolves Au andAg more efficiently and does not show any bad effect on dissolution of other elements.2000timesdilution of pyrite standard solutions could effectively surpress the matrix effect of iron and alsoachieve the purpose of accurate determination of different content-level elements.The applicationof this method will allow more precise discussion of pyrites and other sulfides crystallizationconditions and enrichment mechanism about the associated Au, Ag and other precious metalelements. Using this method to take pre-treatment and analyze two stages pyrites（Ⅰand Ⅱ） from theSandaowanzi Au deposit in Da Hinggan Range. The results demonstrate that Au, Te and Agcontents in stage Ⅱ pyrites are higher than stage Ⅰ pyrites, indicating that stage Ⅱ pyrites areimportant carriers for Te-Au-Ag. This study implies that this method, which has advantagesofsmall sampling quantity, simultaneous and high accuracy analysis to measure REE, transitionelement, LILE and HFSE together with Au and Ag in sulfides shows good prospects to study oreforming mechanism.更多还原