Study On The Precipitation Mechanism Of Germanium-rich Sphalerite In Huize Lead-zinc Mine

The Huize super-large lead-zinc deposit is located on the southwest edge of the Yangtze platform.It is one of the famous production bases of Pb,Zn,and Ge in China.Because of its high lead and zinc grades(Pb+Zn grades are mostly 25%?35%,some ores Grade more than 60%),many associated useful elements(Ag,Ge,Ga,Cd,In,etc.).This article will take the Huize lead-zinc deposit as the research object,combined with the previous research results,conduct the following research and obtain the following understanding:1.Combined with previous studies and this study,the Huize lead-zinc deposit metallogenic stage is divided into:sphalerite-pyrite-calcite stage,sphalerite-galena-pyrite-pyrite-calcite stage,yellow iron Ore-galena-zinc blende-calcite-calcite stage,the corresponding zinc blende is divided into three generations corresponding to three metallogenic stages;2.ICP-MS and La-ICP-MS data of ore and gangue minerals in the mining area show that the germanium-rich mineral in the Huize lead-zinc deposit is sphalerite(zinc blende is also a cadmium-rich mineral),and germanium is mainly rich in It is collected in the third generation sphalerite,followed by enrichment in the first generation sphalerite,and the least content in the second generation sphalerite;3.The sulfur isotope data of sulfide in the mining area indicates that the sulfur in the ore-forming fluid mainly comes from marine evaporites in the formation.The sulfate reduction mechanism is thermochemical reduction(TSR)reaction;and the fractionation mechanism of sulfur isotope in the mining area belongs to dynamic equilibrium Fractional distillation,controlled by oxidation reaction and organic reduction;?34S value characteristics of sphalerite of different generations show that the degree of oxidation in the fluid during the crystallization process of sphalerite of the third generation in the late mineralization stage is enhanced;4.The ore-forming fluids of the Huize lead-zinc deposit have undergone an evolution process from the early metallogenic stage to the late metallogenic stage of medium-medium high temperature-medium high salinity?medium-medium low temperature-medium salinity medium low temperature-medium low salinity;Combining with the change of Ge content in sphalerite in Huize lead-zinc ore,the process of first decreasing and then increasing,it is speculated that the main factor for the enrichment of germanium in the early mineralization stage is the high concentration of Ge in the fluid,while the enrichment in the late mineralization stage The main factors are the decrease in temperature,the increase in the degree of oxidation and the decrease in pH;5.The pH and Eh of the zinc-blende ore-forming fluids of different generations are simply calculated.The results show that from the early ore-forming stage to the late ore-forming stage,the pH value gradually decreases,and the fluid Eh value gradually increases,resulting in The mineral solution system gradually changed from weakly reducing to oxidizing;through research,it was found that the pH and Eh value had an effect on the enrichment of germanium by controlling the activity of germanium hydrosulfide and germanium alloy hydride that migrated with the fluid;6.The 40 Ar-39 Ar method was used to date the clay minerals in the mining area and the metallogenic age of the Huize lead-zinc deposit was between 200.39 and 226,26 Ma.The lower age of the metallogenic events in the Sichuan-Yunnan-Guizhou metallogenic area was 174.71 Ma.