Abstract: Mercury-contaminated substances are fed through a shredder to a loader that loads a rotary tubular kiln, in which a mercury content is evaporated by a primary burner. A temperature of an unlined rotary kiln is monitored from an outside at various points over an entire length, by infrared sensors. The thus acquired data are supplied to a regulating unit that regulates fuel supply and primary air supply through various control lines. Burned gas is supplied through a duct to a cyclone separator in which solids are separated and returned to the process. The gaseous substances are fed through a postcombustion chamber of a quench to a washer in which mercury is removed. The residual gas reaches a chimney through an active coal filter. This process is particularly easy to control, economical and allows a particularly low residual mercury content to be reached, for example less than 0.1 ppm, in a residual combustion product.

Abstract: A method to decontaminate radioactively contaminated metallic objects in which the objects are contacted with a non- radioactive, aqueous solution containing acetic acid. The metallic objects are in contact with the acid continuously or successively over several hours until the acid is completely stoichiometrically depleted. The concentration of the aqueous solution containing acetic acid is preferably approximately 0.3 Mol/l. These steps are repeated until the residual contamination of the metallic objects is beneath the desired target threshold of 0.37 Bq/cm.sup.2. The radioactive metallic oxides and metallic hydroxides in the aqueous stoichiometrically depleted solution are sedimented out, and the sludge is solidified with cement and subsequently decontaminated.

Abstract: A method for decontaminating a radioactively contaminated metallic object. A radioactively contaminated metallic object is placed into a first bath and thus contacted with a non-radioactive, aqueous solution containing formic acid until the formic acid is completely stoichiometrically depleted thereby forming an aqueous, stoichiometrically depleted solution. The metallic object is then placed into a second bath of the same chemical composition. The non-radioactive, aqueous solution of the second bath is also preferably completely stoichiometrically depleted. The concentration of the aqueous solution containing formic acid is preferably about 0.3 Mol/l. These steps are repeated until the residual radioactivity level of the metallic object is beneath a permissible threshold level, such as 0.37 Bq/cm.sup.2. The radioactive metallic oxides and metallic hydroxides are sedimented out, and the sludge is solidified with cement and subsequently decontaminated.