FIELD: purifying pyrogas. SUBSTANCE: carbon dioxide and hydrogen sulfide are absorbed by aqueous solution of sodium hydroxide. The process is carried out at elevated temperature. Thus treated soluton is extracted by fraction of aromatic hydrocarbons, aqueous phase of sodium hydroxide being separated by sustaining and is then cooled to 0.5-5 C. Crystallized precipitate of sodium carbonate is separated of mother solution and is washed by concentrated solution of sodium hydroxide. The latter process is carried out at 0.5-5 C, it is followed by heating to 40-80 C. Portion of washing and mother solutions is recycled for absorption. Cold residue of washing solution (40-80 %) is recycled to wash precipitate of sodium carbonate. Disposal portion of mother solution is evaporated till total alkaline content is 200-320 g/l (as calculated for sodium hydroxide). Elementary sulfur is added into mentioned above evaporated solution, its quantity being 1-3 moles per one mole of sodium hydroxide and sodium sulfide. EFFECT: improves efficiency of the method. 3 cl, 3 tbl, 1 dwg
