硫化物矿物对银的表面吸附作用及其成矿意义  

ADSORPTION OF SILVER IONS ONTO SULFIDE MINERALS AND ITS SIGNIFICANCE IN MINERALIZATION

作　　者：吴大清[1] 彭金莲[1] 陈国玺[1] 

机构地区：[1]中国科学院广州地球化学研究所

出　　处：《地球化学》1996年第4期372-378,共7页Geochimica

基　　金：国家自然科学基金

摘　　要：通过硫化物矿物对银离子的吸附实验研究表明，在５０℃时，硫化物矿物对溶液中银离子的等温饱和吸附量大小顺序是：方铅矿＞黄铜矿＞辉锑矿＞闪锌矿；当温度超过７０℃时，这个顺序变为：辉锑矿＞方铅矿＞黄铜矿＞闪锌矿。这与天然多金属矿床中硫化物矿物银的含量顺序是一致的。实验证明，硫化物具有把溶液中的银富集到固体（矿物中）达１０６量级以上的能力。这些结果极好地解释了多金属矿床中银在普通硫化物中含量大小的顺序及锑和银在矿床和矿物上密切共生的关系。The experiments of the isotherm adsorption of silver ions by sulfide minerals(galena,sphalerite, chalcopyrite and stibnite)and synthetic sulfides (PbS,ZnS and Sb2O3)are carried out at pH=3, t=50°C and ionic strengh I=0.1.The results show that the sulfides are the good capture agents for silver ions and they can concentrate the silver ions from the solution to the solids(sulfides)about 5-6 orders in magnitude. The adsorption density of sulfide minerals with grain size 56-84μm is as follows: galena>chalcopyrite>stibnite>sphalerite.The larger capicity is expected if the mineral grain is more fine. Actually, for the adsorption of silver ions by new precipitated PbS, ZnS and Sb2S3 the capacity is as high as 29.7 mol /kg.The silver concentration in solution is always less than 0.01 mg/L after equilibrium which is less than the flame AAS sensitivity. It means that these sulfides can concentrate the silver ions from solution to solids for more than 6 orders in magnitude. When the temperature raises the adsorption capacities of all sulfides increase linearly. As t>74°C,the adsorption capacity is:stibnite>galena>chalcopyrite>sphalerite. This can be proved by the silver contents in sulfides found in polymetallic ore deposit except for stibnite. The results explain why the silver exists always in the sulfide minerals and is commonly associated with stibium and exsits in form of antimony sulfosalt minerals. The results also suggest that the adsorption of silver ions by sulfides plays an important role in silver concentration in the sulfides during the mineralization of polymetallic ore deposits.

关 键 词：硫化物 吸附 银离子 银 成矿 多金属矿床 

分 类 号：P618.205[天文地球—矿床学]