Abstract: A method and apparatus are disclosed for the treatment of paint sludge and for reducing volatile organic compound emissions from a paint spraybooth operation, thereby obtaining a recyclable material for use in new coating products. In such an operation, uncured paint resins mixed with volatile organic compounds are sprayed onto an article to be painted and at least a portion of the overspray is mixed with water to form a waste stream containing water, uncured paint resin, volatile organic compounds and inorganic substances. The method includes the steps of: removing a portion of the water and liquid volatile organic compounds from the waste stream; heating the resultant sludge to volatilize the residual water and liquid volatile organic compounds and to cure the uncured paint resin; collecting the residual solids stream, and removing all of the volatilized organic compounds from the resultant stream, thereby generating a volatile organic compound-free gas effluent.

Abstract: Volatile matter especially solvents is recovered from waste material using a hot granular material such as sand, as a heat carrier to drive off the solvents, and as a carrier for the non-volatile resin content of the waste; the resins are thermally decomposed in reactions which provide heat to maintain the granular material hot and the granular material is continuously circulated; the exhaust gases from the thermal decomposition of the resins can be used as a source of heat outside the system.

Abstract: A device for and method of working up etching and pickling liquids consisting of a vertical furnace having one or more vertical reaction spaces through which balls move at a maximum packing density.The furnace has a temperature gradient from the bottom (high) to the top (low). The reaction space and the balls consist of a material which is inert with respect to the liquid to be worked up. The liquid is introduced into the upper side of the furnace so that a film is formed in the heated surface of the balls. The salt dissolved in the liquid decomposes pyrolytically. The metal oxide is deposited on the surface of the balls and is removed therefrom after leaving the reaction space. The acid residue vapours are drained at the top and recovered in a separate absorber to the original pickling or etching acid.