Andritz-Patentverwaltungs-Gesellschaft M.b.h.

Andritz Ag

Albert Lebl

A process for the recovery of metal oxides from a solution containing metallic salts by spray roasting of these solutions. The process is particularly suitable for spray roasting spent pickling acids. The process feeds the solution to a reactor for spray roasting of the droplets in at least two stages, where at least one evaporation stage follows at least one conversion stage to convert the metal salts to metal oxides. The device for implementing the process includes a spray roasting reactor having a first heating zone to evaporate the water and a second heating zone to convert the metal salts to oxides.

Process and apparatus for the recovery of metal oxide particles

Process and apparatus for regenerating spent acid liquor includes a primary roasting furnace for evaporating a substantial portion of the liquid from the spent acid to produce acid vapors and partially roasted metal salts. The partially roasted metal salts are transferred to a secondary roasting chamber where the acids adhering to the surface of the metal salts is vaporized and the metal salts are oxidized. The acid vapors from the primary roasting furnace are then transferred to an absorption column to regenerate the acid. The primary roasting furnace is operated at a different temperature from the secondary roasting chamber and has different retention times for the metal salts. The secondary roasting chamber includes a raking device to mix and convey the metal salts during the secondary roasting step to produce a uniformly roasted metal oxide.

Process and apparatus for the extraction and regeneration of acids from spent acids

A process for regenerating spent acid liquor feeds an acid liquor into a reactor having a first heating zone for evaporating a substantial portion of the liquid from the spent acid to produce acid vapors and metal salts without decomposing the acid. The metal salts are transferred to a second heating zone where the salts are roasted to form metal oxides. The acid vapors from the primary roasting furnace are then transferred to an absorption column to regenerate the acid. The first heating zone is operated at a temperature below the decomposition temperature of the acid and the metal salts. The second heating zone operates at a higher temperature to completely oxidize the metal salts.

Process for regeneration of acids from spent acids

Process for the extraction and regeneration of acids from spent acids

Process for extraction or recovery of acids, in particular hydrofluoric acid, hydrochloric acid and nitric acid, from solutions of these acids containing metal, by pyrohydrolytic treatment and subsequent absorption and/or condensation of the acid gases thus formed in an aqueous absorption solution, in which process the solids produced are removed. In order to guarantee economical acid recovery in existing plants without requiring large-scale adaptation, the waste pickling liquor is subjected to pre-concentration first of all before pyrohydrolysis, using the heat contained in the exhaust gas from the pyrohydrolysis. In a device for extraction or recovery of acids in particular hydrofluoric acid, hydrochloric acid and nitric acid, from solutions of these acids containing metal, comprising a feed pipe for the solution, a pyrohydrolysis reactor, and at least one absorption or condensation column connected to the exhaust gas pipe from the reactor, a device is provided for pre-concentration and upgrading of the solution.

Process and plant for extraction or recovery of acids from solutions of

A process is disclosed for removing the very fine oxide particles produced during regeneration of used pickling acids by pyrolysis. The process includes the step of spraying water into the gaseous stream to produce a mist of fine droplets and thereafter passing the gaseous stream through a liquid separator. The invention is also directed to a plant for carrying out the process where the plant includes a nozzle to spray water droplets into the gaseous stream before the drop separator.

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Vienna, Austria

Albert Lebl