Abstract: The present invention relates to a method for removing a silicic compound from the waste liquor of steel pickling. A filtering method using a filter fabric or biscuit plate is impractical as an industrial method because the filtering medium becomes clogged.The present invention is characterized by an adsorption method in which silicic compounds are adsorbed on adsorbent substrates in an optional part of an adsorption bed.The present invention is characterized in that the waste liquor is passed through the adsorption bed for a two-month period or longer without clogging occurring.