Patent Number: 054535620
Section: claims

1. A method for separating volatile and semi-volatile chemical contaminants from contaminated mixed waste feed materials comprising, subjecting the feed materials contaminated with chemical compounds to a vacuum sufficient to expose the feed materials to a final pressure from about 400 mm Hg to about 50 mm Hg; simultaneously heating the feed materials to a temperature effective to volatilize the volatile and semi-volatile chemical contaminants, but below incineration temperature and below thermal desorption temperatures required at atmospheric pressure; substantially continuously removing the evolved vapors for a period of time sufficient to effect a desired degree of separation of the volatile and semi-volatile chemical contaminants from the feed materials. 2. A method as in claim 1, wherein the temperature employed to effect volatilization is equal to or below 600.degree. F. 3. A method as in claim 1, wherein the volatile and semi-volatile contaminants comprise halogenated organic chemicals. 4. A method as in claim 1, further comprising passing an inert gas other than steam through inert solids. 5. A method as in claim 4, wherein the inert gas is selected from the group consisting of nitrogen, carbon dioxide, helium and argon. 6. A method as in claim 1, wherein the concentration of any single organic contaminant in the treated feed materials after treatment is 25 ppm or less. 7. A method for separating volatile and semi-volatile chemical contaminants from contaminated mixed waste feed materials comprising, subjecting the feed materials contaminated with chemical compounds to a vacuum sufficient to expose the feed materials to a final pressure from about 400 mm Hg to about 50 mm Hg; simultaneously heating the feed materials to a temperature effective to volatilize the volatile and semi-volatile chemical contaminants, but below incineration temperature and below the thermal desorption temperature required at atmospheric pressure; substantially continuously removing the evolved vapors for a period of time sufficient to effect a desired degree of separation of the volatile and semi-volatile chemical contaminants from the feed materials, wherein the evolved vapors are treated prior to atmospheric discharge. 8. A method as in claim 7, wherein the temperature employed to effect volatilization is equal to or below 600.degree. F. 9. A method as in claim 7, wherein the contaminants comprise halogenated organic chemicals. 10. A method as in claim 7, further comprising passing an inert gas other than steam through inert solids. 11. A method as in claim 10, wherein the inert gas is selected from the group consisting of nitrogen, carbon dioxide, helium and argon. 12. A method as in claim 7, wherein the concentration of any single organic contaminant in the treated feed materials after treatment is 25 ppm or less. 13. A method for separating volatile and semi-volatile chemical contaminants from contaminated mixed waste solid materials comprising, in combination, the steps of: (a) removing from the ground solid materials contaminated with hazardous and radioactive pollutants;  (b) introducing the contaminated solid materials into a batch mixing vessel;  (c) drawing a vacuum on the mixing vessel while purging the mixing vessel with an inert purge gas;  (d) agitating the contaminated solid materials in the mixing vessel in the presence of the inert gas while indirectly heating the solid materials to a temperature between about 200.degree. to about 600.degree. F.;  (e) simultaneously with the heating and agitation of step (d) continuously drawing a vacuum until a final pressure from about 400 mm Hg to about 50 mm Hg on the mixing vessel is reached while maintaining a sweep stream of an inert gas; and  (f) continuously removing by means of the vacuum, evolved vapors comprising substantially all of the volatile and semi-volatile chemical compounds originally contained in the contaminated solid materials.