Method and apparatus for treating a gas mixture

The present invention relates to a method (100) for treating a starting gas mixture comprising carbon dioxide, hydrogen and water, the starting gas mixture being produced including a Claus process (1), wherein the method comprises forming at least one product fraction predominantly or exclusively containing carbon dioxide. According to the present invention, the starting gas mixture is enriched in carbon dioxide and hydrogen and depleted in water in a first group (10) of method steps forming an intermediate gas mixture, the first group (10) of method steps including compressing (11), cooling (12, 13), condensing and drying (13), and ,in that the intermediate gas mixture rs at least partially submitted to a second group of method steps (20), the second group (20) of method steps including subjecting at least a part of the intermediate gas mixture to a partial liquefaction (21, 22, 23) forming a liquid fraction and a gaseous fraction, the liquid fraction being at least partially used in forming the at least one product fraction. A corresponding apparatus is also disclosed.