Technical Bulletin No. 0059: The Electrodialysis of Ammonia Base Liquor for Ammonia Recovery

A major shortcoming of ammonia base sulfite pulping is the lack of a practical method for recovering the base from the spent pulping liquor. Electrodialysis has been finding increasing use in effecting chemical recoveries in other industries and the advent of new membranes for use in this process is broadening its scope of application. The enclosed technical bulletin describes preliminary studies, conducted by the Council’s project at Oregon State College, on ammonia recovery from spent liquor by electrodialysis employing a cationic plastic membrane. Results indicated that ammonia could be recovered at suitable strength at a relatively low power requirement and were of sufficient promise to warrant continuation of these studies. Future plans include tests of various types of membranes under wide ranges of applied current, as well as an evaluation of other process factors.