A method for producing aqueous hydrochloric acid from flue gases is provided. The method comprises conveying water to a first scrubber (102, 202, 302, 402, 502, 602, 702) or to a line (112b, 212b, 312b, 412b, 512b, 712b, 712c) to use the water in a scrubbing liquid of the first scrubber. The method also comprises providing flue gas containing chlorides into the first scrubber (102, 202, 302, 402, 502, 602, 702) and scrubbing the flue gas containing chlorides with the scrubbing liquid by contacting the flue gas with the scrubbing liquid in the first scrubber (102, 202, 302, 402, 502, 602, 702). Dilute hydrochloric acid and a flue gas derivate (104, 204, 304, 404, 504, 704) are produced. The method comprises letting out at least some of the dilute hydrochloric acid from the first scrubber (102, 202, 302, 402, 502, 602, 702) as a scrubber bleed, separating solids suspended by the scrubber bleed in a solids separator (192, 592, 692), conveying the scrubber bleed from the solids separator (192, 592, 692) into an evaporation vessel (194, 594, 694) and concentrating the scrubber bleed in the evaporation vessel (194, 594, 694) to produce hydrochloric acid vapor having a concentration of 5-22 wt-%. A corresponding system is also provided.