Method of producing activated carbon from pit-wet lignite

A method of producing an activated carbon from pit-wet lignite by an activation reaction, consisting essentially of adding potassium ions to the pit-wet lignite and then adding water vapor and simultaneously heating the pit-wet lignite to a temperature of at least 600.degree. C. for a time sufficient for activation and subsequently washing with water, to obtain an activated carbon which displays improved adsorption capacity, wherein up to 2% by weight potassium ions on a dry basis are added to the lignite and said water vapor being present in an amount sufficient to improve the adsorption capacity of said activated carbon.