FIELD: gas treatment. SUBSTANCE: invention concerns evaporation of black sulfate liquor to selectively remove, using liquid absorption, hydrogen sulfide from gas containing hydrogen sulfide and carbon dioxide. Gas is brought in countercurrent multistep contact with recycling carbonate-containing alkali solutions, preferably sodium carbonate solutions, their pH being adjusted in absorption process to value 9-12 by adding hydroxide (preferably sodium hydroxide). Contacting is preferably carried out in three steps. It is desirable gas stream when contacting to be turbulent and liquid stream laminar. Apparatus has filled container with gas inlet and outlet fittings, filling being disposed in several consecutive steps. Apparatus includes means to feed carbonate-containing solution into the last step and, in contact with gas, into the other side of the same step to provide solution recycling. There are pipelines located between the steps to transfer a part of liquid stream from one step into preceding one, means to introduce hydroxide into carbonate- containing solution at least in one step, and also discharge pipeline from the first step in gas direction to discharge sulfide-containing liquid. EFFECT: enhanced efficiency of process. 10 cl, 1 dwg
