Study On The Technology Of Separation And Concentration Of Cadmium From Spent Nickel-Cadmium Batteries By Emulsion Liquid Membranes

Liquid membrane separation technology is a kind of membrane separation technology with a great potential application. In this study, the new technology was used to separate and concentrate cadmium from the leaching solution of spent Ni-Cd batteries and good results were achieved.After conducting a pre-treatment of spent Ni-Cd batteries, this experiment implemented leaching according to the need of experiment, and then detected the mass concentration of Cd,Ni,Co in the leaching solution with the apparatus of ICP-AES.This experiment investigated the stability of W/O single emulsion made by T154 and Span80 from four factors—namely, the types and content of surfactant, emulsifying steering speed, volume ratio of oil phase and the concentration of NaOH in inner phase. According to the result, T154 was selected as the liquid membrane surfactant of the following experiment.The emulsion liquid membrane system disposes of the leaching solution from spent Ni-Cd batteries, with dialk eny 1 succinimide (T154) as surfactant, tri-n-octylamine (TOA) as the carrier, kerosene as a solvent, liquid paraffin as the strengthening agent, sodium hydroxide as an internal phase was established. Single factor experiment and orthogonal experiment method were used to determine the optimal membrane phase composition and operating conditions. Under the optimal conditions, the mean ion migration rate are:R(Cd2+)=97.11%, R(Ni2+)=4.49%, R(Co2+)=3.58%。The emulsion liquid membrane system disposes of the leaching solution from spent Ni-Cd batteries, with dialk eny 1 succinimide (T154) as surfactant, tributyl phosphate (TBP) as the carrier, cyclohexane as a solvent, ethylhexanol as the strengthening agent, sodium hydroxide as an internal phase was established. Single factor experiment and orthogonal experiment method were used to determine the optimal membrane phase composition and operating conditions. Under these conditions, the mean ion migration rate are:R(Cd2+)=97.52%, R(Ni2+)=5.41%, R(Co2+)=3.46%. At last, the experiment of electrostatic demulsification to break the emulsion and comparatively WAS conducted to investigate the effect of breaking voltage and breaking time on breaking emulsion rate of the two emulsion systems concerned above. At the fixed condition of demulsification voltage 250V and time of 18min, the two kinds of emulsion systems could achieve the separation of oil-water phases and be able to recycle oil phase and water phase.