FIELD: chemical technology. SUBSTANCE: method involves absorption of carbon dioxide and hydrogen sulfide with sodium hydroxide aqueous solution at elevated temperature, refinement of spent absorbent from organic impurities by extraction with aromatic hydrocarbon fraction, separation of organic phase from an aqueous one that contains sodium hydroxide and carbonate by settling. Then method involves an aqueous phase heating to 80-105 C, its settling for 3-15 hr, evaporation of obtained aqueous phase to the total alkalinity 165-360 g/l (measured as sodium hydroxide), sodium carbonate crystallization from an aqueous phase by cooling at 0-10 C, separation of sodium carbonate precipitate from mother liquor, its washing with concentrated sodium hydroxide solution at 0-10 C and recovery 30-70% washing solution to absorption. Remained part is fed to sodium carbonate washing, part of mother liquor is fed to adsorption, its remained part is processed by addition of concentrated hydrogen sulfide-containing gas and/or elemental sulfur up to saturation degree with hydrogen sulfide and elemental sulfur 0.3-0.5 and 0.3-3 mole per mole sodium hydroxide, respectively. Elemental sulfur is added to mother liquor at stirring at 40-80 C. Proposed method ensures to increase sodium carbonate yield from 14.2-38.6 to 25.0-72.5%, i. e. by 10.8-33.9% and its quality also. Sodium sulfide and/or polysulfide obtained can be utilized at retained high level of purification of pyrogas from acid components. Removal of toxic solution is excluded. Method is used in chemical, oil processing and petroleum chemical industries. EFFECT: improved method of scrubbing, improved ecology, increased yield of product. 2 cl, 1 dwg, 3 tbl, 3 ex
