低温条件下锡的实验地球化学研究

Experimental Geochemical Research of Tin at Low Temperature

低温条件下锡的实验地球化学研究＠陈紫新￥中国科学院地球化学研究所锡的可溶性，络合作用，实验地球化学，低温体系低温条件下锡的实验地球化学研究陈紫新（中国科学院地球化学研究所，贵阳５５０００２）关键词锡的可溶性络合作用实验地球化学低温体系目前，国内外对锡的成矿...

In order to model the complexation between tin and chloride,hydroxide,silica at lower temperatures,a quantitative experiment of chemistry was calibrated at different temperatures,oxygen fugacities and pH conditions.Thermodynamic calculations showed that(1) with fO2 of NNO at 250℃,SnCl+ was dominant in SnO_2HClH_2O system (Sn^2++Cl=SnCl+,logK=2.969)。(2) At lower temperature and higher oxygen fugacity (such as HM),tinhydroxide (Sn(OH)04) was much more important than tinchloride for tintransport.(3) The fO2 of HM,the equilibrium constants for the cassiterite dissolution reaction in solution were given by Sn4++4OH=Sn(OH)04,logK=83.229-1.889×104/t.(4)With fO_2 of HM at 200℃,the complexation between tin and silica was calibrated as:Sn4++4H3SiO4=Sn(H_3SiO_4)04,logK=40.962±3.0.The dissolution of cassiterite in aqueons SiO2 solution could be described as :SnO2+4H4SiO04=Sn(H_3SiO_4)04+2H_2O,logK=-0.5021,which indicated that there was a close association between silication and tin mineralization.