Study Of ICP-MS Detection About Trace Elements And Noble Metal Elements In Sulfides

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.