A method of removing mercury from flue gas containing mercury and particulate solids emanating from a fossil-fuel energy conversion plant and passing through a flue gas duct. The method includes (a) contacting the mercury in the flue gas with a solution containing at least one chloride-containing salt dissolved in a solvent by injecting the solution into the flue gas duct at an injection location, in order to oxidize mercury into HgCl₂, (b) heating the solution prior to or after step (a) to at least about 300 C., and (c) removing oxidized mercury from the flue gas with a device for removing particulate solids from the flue gas.