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.

Abstract: Compositions of matter are provided by the invention herein which compositions may be in liquid or solid forms depending upon their projected uses, all of which provide fire retardancy in said uses which generally involve shaped articles such as coatings or moldings. The fire retardancy objective is accomplished by locking water into or available to the shaped article by the provision of an inorganic salt hydrate, such as aluminum sulfate hydrate or ferrous sulfate hydrate and by providing also a hydraulic cement, such as Portland cement. The powdered mixture of the salt hydrate and cement may also preferentially contain an alumina silica material which preferably is in fibrous form having fibers in it that have lengths of about 0.25 to about 2.0 inch. Also present in said powder may be an iron oxide and a manganese oxide, such as ferric oxide and manganous oxide, respectively. In certain instances graphite is incorporated into the mixtures, as in the case when epoxy polymers are used.

Abstract: A process for regenerating waste acid, such as waste hydrochloric acid pickling liquor by producing aqueous hydrochloric acid of pickling concentration and generating iron oxide including that of pigment grade, comprises the steps of (1) concentrating the waste liquor, (2) reacting the concentrated liquor at a temperature below 1000.degree. F.

Abstract: A system for regenerating waste acid, comprises (1) a concentrator for concentrating the waste liquor, (2) a reactor for reacting the concentrated liquor at a temperature below 1000.degree. F. in the presence of oxygen and hydrocarbon combustion gases and on a recycled moving bed of particles without vibration of the reactor bottom, (3) a separator for separating the iron oxide dust from the other gases from the reactor, (4) the same concentrator cools these gases, (5) an absorber for absorbing the hydrogen chloride cooled gas in an aqueous solution from the following scrubber, (6) a scrubber for scrubbing the unabsorbed gases in water to absorb the hydrogen chloride gas remaining in the gases from the absorber, and (7) a condenser for condensing any liquids and any residual HCl remaining in the exhaust gases before exhausting them as non-polluting gases into the atmosphere and passing the condensate back into the waste acid concentrator.