Abstract: A method and apparatus are provided for treatment of acid fumes to reduce the acid content of the fumes to meet the stringent environmental requirements. The acid fumes are treated in a packed zone containing, as the packing materials, polyester resins treated with aluminum sulfate crystals.

Abstract: A system for the chemical cleaning of metal, for example, the acid pickling of steel, includes one or more tanks containing a corrosive liquid bath in which the liquid is flowed rapidly relative to the metal and held at a temperature in excess of 180.degree. F. The tanks comprise an outer metal shell whose internal wall is protected by a layer of a rubber-like material. In one embodiment the rubber-like layer is protected from the hot corrosive liquid by panels of fiberglass reinforced plastic (FRP) which are overlapped in a shingle pattern. In another embodiment, an inner tub (tank) of FRP floats on a layer of water which is held between the inner FRP tub and the layer of rubber-like material which covers an outer metal shell.