During the Great Proletarian Cultural Revolution, a "three-in-one" combination research group was organized from the workers, which formed the main-force, cadres and technical staffs of Silicon-Steel Sheet Works, Metallurgical Designing Institute and a research institute, for the recovery of sulphuric acid from the waste acid liquor of the steel works.Through the employment of our 5-203 anion ezohange membrane by way of diffusion-dialysis, a fairly satisfactory resint was obtained with an economy of the material as well as an improv.ment of the environment.