FIELD: oil and gas production. SUBSTANCE: method includes treating raw material with water-alkali solution of ferric complexonate at pH 7.1-10 and ferric complexonate/hydrogen sulfide molar ratio (0.5-1.9):1; isolation of purified product; regeneration of exhausted solution by blowing it through with air; separation of resulting elementary sulfur from regenerated solution by filtration or centrifugation; and recycling regenerated solution into raw material treatment stage. As alkali agent in water-alkali solution of ferric complexonate at pH 7.1-10, alkali and/or metal phosphate and/or water-soluble organic amine are used. The former are preferably sodium or potassium phosphate or polyphosphate, and the latter mono-, di-, triethanolamine, N-methyldiethanolamine, N,N- dimethylethanolamine, or their mixtures. Raw material containing hydrogen sulfide and mercaptans is advantageously treated at molar proportion of ferric complexonate to hydrogen sulfide sulfur plus mercaptan sulfur (0.5-1.9):1. EFFECT: enhanced process efficiency. 7 cl, 10 ex
