The Study Of Recycling Alkaline Etching Waste Solution By Emulsion Liquid Membrane Technology

With the rapid development of printed circuit board （PCB） industry, a largeamount of etching solution have been annually produced, which do harm to theenvironment. If etching solution were poured to the pipeline directly without beenproperly handled, the receiving water would be contaminated. What more, etchingsolution is a kind of resources, which is rich in copper. Handling not properly couldcause a waste of resources. At present, there are several traditional methods, but theystill existed some shortcomings, such as secondary pollution、fail to reach thestandard、high consumption of energy、low efficient and high cost. So this paper isaimed at recycling alkaline etching waste solution by emulsion liquid membranetechnology, which can not only regenerate etching waste solution but also can recyclecopper, applied effectively and economically.Stabilization of emulsion liquid membrane is studied in this paper. We comparewith the Stabilization of two types of emulsion liquid membrane made by surfactantspan-80and T154respectively by breakdown rate and apparent swelling as measuredstandard. The result shows that no matter you use sulfuric acid or ammonia as internalphase, emulsion liquid membrane with T154is more stable than it with span-80.Therefore, T154has been chosen as surfactant of emulsion liquid membrane system.Then copper in the preparing etching solution has been extracted on goodcondition through emulsion liquid membrane system made by T154-N910-H2SO4andT154-N910-NH3·H2O. The result shows that the good conditions for the extraction ofcopper from preparing etching solution by emulsion liquid membrane system made byT154-N910-H2SO4are as follow: the speed of making emulsion is3500r·min^-1,making emulsion time is10min, extraction time is10min, the concentration of innerphase is3.0mol·L^-1. volume ratio of membrane phase to internal phase is1:2, volumeratio of membrane phase to external phase is2:5, the volume of surfactant andextractant are3%and5%respectively, the pH of external phase is9.5, stir speed isaround275r·min^-1. The good conditions for the extraction of copper from preparingetching solution by emulsion liquid membrane system made by T154-N910-NH3·H2O are as follow: the speed of making emulsion is3000r·min^-1, making emulsion time is10min, extraction time is10min, the concentration of inner phase is12mol·L^-1.volume ratio of membrane phase to internal phase is1:2, volume ratio of membranephase to external phase is2:5, the volume of surfactant and extractant are3%and5%respectively, the pH of external phase is9.5, stir speed is around250r·min^-1. By usinghigh voltage electrostatic method to demulsificate the emulsion liquid membrane, thecopper in inner phase from two kinds of systems both reached60g/L. Applying twokinds of emulsion liquid membrane to the treatment of alkaline spent etching solution,on such condition discussed above, the effect is nearly the same as the effect ofdealing with preparing etching solution, after dealing with the preparing etchingsolution through three level processing, etching solution reached the recyclingstandard.Finally, the purity of product and economy of dealing methods are analyzed,indicating that the purpose of recycling copper ion resources and regenerating alkalinespent etching solution can be achieved.