| The electrolytic capacitor is widely used in modern electronicdevices, and its market demand keeps a rapid growth. China is the largestproducer of aluminum electrode foil for electrolytic capacitors. Duringthe corrosion process large amount of waste acids, containing mass freeacids and soluble aluminum species, are produced, which may causeserious environmental pollution as well as waste of resources. The goal ofthis study is to explore efficient method to recycle the waste acid. Thecontent consists of the following three parts:1) Design and build a diffusion dialysis system (DD). DD canseparate free acid from the aluminum salt in the waste acid by using thepermselecitivity of ion exchange membrane with concentration differenceon both sides of the membranes as ion migration force. Simulated wasteacid is treated by DD and reaction conditions is optimized.2) Electrolytic system is used to convert simulated aluminiumchloride solution to poly aluminium chloride. Electrolytic conditions areinvestigated to optimize the process. Calculation and analysis on thecost,current efficiency et al. for pilot scale test are contained in this part.3) Electrodialysis with bipolar membrane (EDBM) is introduced andcoupled with DD to recover the simulated waste acid. In this processhydrochloric acid recycling and aluminum salt concersion into PACperform simultaneously and finally achieve zero-emissions. Reactionconditions is optimized and calculations on the cost,current efficiency etal. for pilot scale test are showed in this part. |
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