硫化物吸附金属离子的实验研究──Ⅰ类型

EXPERIMENTAL STUDY ON ADSORPTION OF METAL IONS ONTO SULFIDES (I):TYPES

合成ＰｂＳ、ＺｎＳ对金属离子Ａｇ＋、Ｃｕ（２＋）、Ｃｄ（２＋）、Ｚｎ（２＋）、Ｆｅ（２＋）、Ｍｎ（２＋）、Ｍｇ（２＋）、Ｓｂ（３＋）和Ｂｉ（３＋）的吸附等温线（５０℃）研究表明，其可分为Ａ、Ｂ、Ｃ三类：Ａ类，线性型，即吸附量随吸附离子浓度增加而呈线性上升，并表现出百分之百吸附，属于此类的吸附有ＰｂＳ对Ａｇ＋、Ｃｕ（２＋）离子吸附和ＺｎＳ对Ａｇ＋、Ｃｕ（２＋）、Ｃｄ（２＋）离子的吸附；Ｂ类，朗谬尔型，即随吸附离子的浓度增加，吸附量逐趋向一饱和值，属于此类的有ＰｂＳ对Ｆｅ（２＋）、Ｓｂ（３＋）、Ｂｉ（３＋）等离子及ＺｎＳ对Ｆｅ（２＋）、Ｍｎ（２＋）、Ｍｇ（２＋）等离子的吸附；Ｃ类，反朗谬尔型，即吸附量随吸附离子浓度增加而呈非线性增加。属此类吸附的有ＰｂＳ对Ｚｎ（２＋）、Ｃｄ（２＋）等离子的吸附。合成ＰｂＳ、ＺｎＳ对金属离子的吸附量与天然方铅矿和闪锌矿中微量元素含量可类比，这意味着吸附作用可能在硫化物矿物微量元素形成过程中起着重要的作用。

The adsorption isotherms of metal ions of Ag+,Cu(2+),Cd(2+), Zn(2+),Fe(2+),Mn(2+),Mg(2+),Sb(3+) and Bi(3+) by newly precipitated sulfides PbS and ZnS were deteimined at 50℃ under conditions of PH=3 and I=0.1(NaCl or Na2SO4).Based on the isotherm curves there are three types of adsorptions:A.the linear-type,i.e.,the density increases linearly with increasing of adion concentration.And 100% adsorptions are always observed even the density as high as 30 ×10(-3)-×10(-3).This type includes the adsorption of metal ions of Ag+ and Cu(2+) by PbS,and Ag+,Cu(2+) and Cd(2+) by ZnS;B.the Langmuir type, the density increases to a saturation value as the adion concentration increases.Their saturation densities are 0.27×10(-3),4.3×10(-3) and 6.0×10(-3) for Fe(2+),Sb(3+) and Bi(3+) ions adsorbed onto PbS,respectively,and 1.0×10(-3),1.3×10(-3) and 1.3×10(-3) for Fe(2+), Mn(2+) and Mg(2+) adsorbed onto ZnS,respectively;C. the anti-Langmnuir type,only the adsorptions of Zn(2+) and Cd(2+) ions by PbS are found in this study.Their densities increase nonlinearly with the adion concentration and can be fitted by the formula of potential adsorption.By comparison of all these densities with the maximium contents of those elements in natural sulfide of galena and sphalerite from polymetal ore deposits in China,we find that all of the maximium contents are not beyond the maximium densities (or saturation densities),except that of the Fe and Mn in sphalerite,which may result from the coprecipitation or alternation during mineral forming.Even though the mangnese contents in the most of sphalerite in nature are not beyond the saturation density.This fact suggests that the adsorption may play an important role during incorporation of trace elements into those sulfide minerals.