The aggregated laboratory tests on metallurgical gases clearing from sulphur dioxide by alumino-sulfate method is presented. One-stage and two-level schemes of gas clearing with low (0,19–1,2 %) the concentrating of sulphur dioxide in stationary and selected modes are carried out. Degree of treatment is more than 97 %. The paper shows, that counterflow continuous two-level scheme of clearing with reception of pure commodity plaster is the most effective for gas desulfurization with low concentration of SO₂