Study On The Occurrence State Of Cd And The Release Flux Of Tailings In Hunan Shuikou Shan Mining Area

The paper takes the Kangjiawan deposit of Shuikoushan Mining Area in Changning City,Hunan Province as the research object,Through the microscopic observation of rock ore,tailings and other samples,single mineral test and analysis,X-ray diffraction analysis,electron probe experimental analysis,tailings sand element and particle size experimental analysis,as well as integrating previous research results,Discuss and analyze the rock geochemical characteristics of Shuikoushan Mining Area,Cd and other elements occurrence state,the characteristics of tailings reservoir elements,as well as waste rock heap tailings weathering and oxidation of heavy metal elements during the release of flux and so on.The main ore minerals of Kangjiawan deposit in Shuikoushan Mining Area are galena,sphalerite and pyrite,ore is mainly composed of massive,disseminated,brecciated,ribbon,veins and other networks.Ore structure is mainly semi-self-shaped-it is granular,significant skeletal structure.Exposed to the surface rock to sandstone,basically no granodiorite,all showed different degrees of weathering.The Zn,Pb,Cd and other heavy metal elements were significantly higher than the crustal element abundance.The average contents of Pb,Zn,S,Cd and As in sphalerite were 0.63%,58.43%,32.51%,3043.7?g/g and 40.64?g/g,respectively.The average contents of Pb,Zn,S,Cd and As in pyrite were 0.53%,0.22%,49.18%,24.25?g/g and 6123.86?g/g,respectively.The average contents of Pb,Zn,S,Cd and As in galena were 74.32%,7.18%,16.28%,375.9?g/g and 70.85?g/g,respectively.Sphalerite,pyrite are the main minerals of Cd and As elements.By electron probe and correlation analysis,it was found that the main form of Cd in sphalerite is the substitution of Zn by the isoptic system.The main elements of Baoshiling tailings are SiO2,Al2O3,CaO,K2O,etc.The main minerals are quartz,calcite,a small amount of dolomite and pyrite.The content of Cu,Zn,As,Cd,Pb and other elements in tailing sand far exceeds the background value of Hunan soil,The contents of heavy metal elements in the tailing profile are obviously different.The contents of Pb,As,Zn,Cu and Cd increase sharply with the increase of depth.Tailings sand particle size varies widely,with a weighted average of70.86?m.Through theoretical calculation,the oxidation rate of pyrite in Lingwei tailings pond is2.75×10^-9mol·m^-2·s^-1,The total annual oxidation is 3.33×10⁹g,Resulting in 1.76×10⁷gPb?7.32×10⁶gZn?8.08×10⁴Cd?2.04×10⁷gAs?6.66×10⁵gCu released into the environment.Pyrite pyrite in the total annual oxidation of 8.0×10⁶g,The annual fluxes of Pb,Zn,Cd,As and Hg were 4.24×10⁴g,1.76×10⁴g,1.94×10²g,2.04×10⁷ g,4.90×10⁴g,respectively.The total annual oxidation of sphalerite is5.78×10⁵g,and the oxidation rates of Zn and Cd are 2.585×10^-8mol·m^-2·s^-1,6.274×10^-88 mol·m^-2·s^-1,their annual fluxes are 3.64×10⁵g,1.76×10³g.