摘要
用测定黑钨矿碳糊电极在比Pb^(2+),Mn^(2+)离子活化下的双电层微分电容变化,探索阳离子活化剂在该矿物浮选过程中的活化机理。黑钨矿碳糊电极是用石蜡油将纯黑钨矿(-0.074mm)和碳粉粘结而成,测定该电极在捕收剂FXL-14(十四烷基亚氨基二次甲基磷酸)及Pb^(2+),Mn^(3+)溶液中的双电层微分电容。结果表明,Pb^(2+)只在较窄的pH值范围使该电极的微分电容具有稍大的变化,而Mn^(2+)则在较宽的pH值范围具有明显的变化,这是因为Mn^(2+)是黑钨矿晶体的同名离子,Mn^(2+)被吸附后,不仅发生化学键合作用,而且嵌入其晶格中。
In flotation of wolframite slime, it can be activated by multivalent metalcations, such as Pb(Ⅱ), Mn(Ⅱ), Fe(Ⅲ) and Fe(Ⅱ). In this paper, double-layercapacitance of wolframite-carbon paste electrode was measured with triangularpotential sweep in Mn(Ⅱ) or Pb(Ⅱ) ion solution, to explain the mechanism. Inthe presence of activate agent of Mn(Ⅱ) or Pb(Ⅱ) cation, the double-layer ca-pacitance of wolframite-carbon paste electrode has gone up from about 2μF toabout 3μF. It has shown that double-layer capacitance of wolframite is influ-enced by the cation. In the presence of activate agent of cation and collectoragent(FXL-14) together, the double-layer capacitance of wolframite-carbon pasteelectrode rises in tbe Mn(Ⅱ) solution at pH=6～10, but in the Pb(Ⅱ) solutionthis phenomenon does not appear. In the presence of activate agent of Mn(Ⅱ),the relation between capacitance and potential has a steep slope, but in thc Pb(Ⅱ)solution, relation between capacitance and potential runs smoothly. In the pre-sence of activate agent of cation of Mn(Ⅱ) or Pb(Ⅱ), and collector agent(FXL-14) together, the double-layer capacitance of wolframite-carbon paste electroderises with the adsorbed time, but in Mn(Ⅱ) solution it has a steep slope, and inPb(Ⅱ) solution it runs smoothly. According to the value of double-layer capa-citance, we can conclude the Mn(Ⅱ)-wolframite has chemical adsorption as pri-mary, and the pb(Ⅱ)-wolframite has physical adsorption as primary, Mn(Ⅱ)is the same name of ion of wolframite crystal. When it is adsorbed by wolfra-mite crystal surface, it can clinch in the wolframite lattice and form the chemi-cal MnWO_4, which adsorb collector easily. So its capacitance rises more than thePb(Ⅱ) solution at pH=6～10. Its capacitance-potential line and capacitance-timeline have a steep slope.
关键词
黑钨矿
矿泥
金属
阳离子
活化剂
wolframite
activate agent of cation
wolframite-carbon paste electrode
collector agent
alkylamino-dimethylphosphonic acid
