Patent Number: 043494650
Section: description

EXAMPLE About 10 kg of a non-radioactive simulated waste mixture was subjected to preliminary comminution. This preliminary comminuted waste mixture had the following composition, by weight, and particle size: ______________________________________ 45% polyvinyl chloride (particle size 5mm) 20% neoprene (particle size 10-15mm) 15% cellulose (particle size 10-20mm) 7.5% granulated polyethylene (particle size 5mm), and 7.5% granulated polypropylene (particle size 5mm) ______________________________________ The preliminary ground waste material was rendered brittle with liquid nitrogen and subjected to a primary comminution where it was ground in a cold-grinding mill at an average temperature of 113.degree. K. (-160.degree. C.). After the primary comminution, 96% of the waste exhibited a particle size smaller than 2 mm. The waste material was then sifted to less than 1 mm, at which size, about 80% passed through the sifter. A suspension was then prepared in a cooled 2-liter, agitated vessel, by adding with agitation, 360 g of the finely comminuted and sifted waste, in incremental portions, to 1.440 kg of 90% H.sub.2 SO.sub.4. The temperature rose during mixing from 295.degree. K. (22.degree. C.) to 311.degree. K. (38.degree. C.). The decomposition of the waste in this suspension was carried out in a 2 liter, electrically heated, forced circulation evaporator (thermal syphon evaporator). Within one hour, 800 g of waste suspension were decomposed at 490.degree. K. (217.degree. C.) at a pressure of 300 m bar. 730 grams of 98% HNO.sub.3 were required for the decomposition. The vapors were condensed at about 343.degree. K. (70.degree. C.) in a condenser, and the non-condensible exhaust gases were removed by suction with the use of a water jet pump from the condenser. The removed non-condensible exhaust gases were fed into a scrubbing column, containing a Raschig ring packing having a height of 1 m. and a diameter of 60 mm. The scrubbing column was rinsed with dilute HNO.sub.3. Within one hour, 250 ml. of 10% H.sub.2 O.sub.2 solution was added to the rinsing liquid. No NO and no NO.sub.2 could be detected any longer in the exhaust gas, withdrawn from the head of the scrubbing column. It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.