25～75℃酸性NaCl溶液中方铅矿的溶解动力学  

Dissolution Kinetics of Galena in Acidic NaCl Solutions at 25～75℃

作　　者：张生[1] 李建平[1] 王玉荣[1] 胡光黔[1] 

机构地区：[1]中国科学院广州地球化学研究所,广东广州510640

出　　处：《地球化学》2002年第6期587-592,共6页Geochimica

基　　金：国家自然科学基金(49973023);广东省自然科学基金(974190)

摘　　要：在25～75℃、pH=0.43～2.45的1mol/LNaCl溶液中进行了方铅矿的溶解动力学实验。发现在远平衡条件下,方铅矿的溶解速率r与氢离子活度犤H+犦呈线性关系,溶解速率方程(速率定律)为:r=k犤H+犦,即对H+而言,溶解反应为一级。其中速率常数k为2.344×10-7mol/m2·s(25℃)、1.380×10-6mol/m2·s(50℃)、7.079×10-6mol/m2·s(75℃)。溶解反应的活化能为43.54kJ/mol,方铅矿的溶解机理为表面化学反应,速率决定步骤为表面配合物的离解。The experiments on galena dissoluti on kinetics are performed in 1mol /L NaCl solutions from pH 0.43to2.45at 25～75℃.The results show that when the dissolution reaction is far from equilibrium,a linear relation exits between the dissolution rate,r,of galena and the hydrogen ion activ ity,[H + ].The rate equation of dissolution is given by the followin g formula:r =k i.e.with respect to hydrogen ion,t he dissolution reaction is first order.The rate con stant,k,has values of 2.344×10 -7 mol /m 2 ·s at 25℃,1.380×10 -6 mol /m 2 ·s at 50℃,and 7.079×10 -6 mol /m 2 ·s at 75℃.The activation energy of dis solution reaction is 43.54kJ /mol.The dissolution mechanism of ga lena is surface chemical reactions,and the rate-determining step is the dissociation of the surface complex,which releases lead ion into the solution.

关 键 词：方铅矿 溶解动力学 速率方程 速率常数 活化能 表面化学反应 溶解机理 

分 类 号：P578.22[天文地球—矿物学]