Westinghouse Electric Corporation

William R Gass

Thomas S Snyder

Laura J Ayers

Samuel A Worcester

Gregory F Boris

David C Phillips

Shyam Vasant Dighe

David F McLaughlin

Luciano C Scala

Gordon A Conn

This invention provides a process wherein hazardous or radioactive wastes in the form of liquids, slurries, or finely divided solids are mixed with finely divided glassformers (silica, alumina, soda, etc.) and injected directly into the plume of a non-transferred arc plasma torch. The extremely high temperatures and heat transfer rates makes it possible to convert the waste-glassformer mixture into a fully vitrified molten glass product in a matter of milliseconds. The molten product may then be collected in a crucible for casting into final wasteform geometry, quenching in water, or further holding time to improve homogeneity and eliminate bubbles.

Plasma vitrification of waste materials

Nickel (or other transition metal) contaminated with about 5 ppm technetium is decontaminated by dissolving the nickel and the technetium into an aqueous acid solution while introducing a graphite or activated carbon powder into the acid to immediately adsorb the dissolving technetium. The technetium-contaminated powder is separated from the aqueous acid solution and the nickel is then electrowon from the solution. The depleted acid solution is then recycled back to the dissolution step.

Transition metal decontamination process

Technetium is separated from nickel by electro-refining contaminated nickel. Electrorefining controls the electrolyte solution oxidation potential to selectively reduce the technetium from the metallic feedstock solution from Tc(VII) to Tc(IV) forcing it to report to the anodic slimes and thereby preventing it from reporting to the cathodic metal product. This method eliminates the need for peripheral decontamination processes such as solvent extraction to remove the technetium prior to nickel electrorefining. These methods are particularly useful for remediating nickel contaminated by radio-contaminants such as technetium and actinides.

Decontamination of radioactive metals

Two alternate, mutually exclusive, methods of removing radio contaminants from metal are taught based respectively on electrowinning or electrorefining of the base metal. The alternative using electrorefining controls the anolyte oxidation potential to selectively reduce the technetium in the metallic feedstock solution from Tc(VII) to Tc(IV) forcing it to report to the anodic slimes preventing it from reporting to the cathodic metal product. This method eliminates the need for peripheral decontamination processes such as solvent extraction and/or ion exchange to remove the technetium prior to nickel electrorefining. The other alternative method combines solvent extraction with electrowinning. By oxidizing technetium to the heptavalent state and by using mixtures of tri-n-octyalphosphine oxide and di-2-ethyl phosphoric acid in aliphatic hydrocarbon carriers to extract the radio contaminants prior to electrowinning, the background metal may be recovered for beneficial reuse. Electrowinning may further polish the decontamination extraction process to remove residual actinides in solution while winning a radio- chemical free metal product. These methods are particularly useful for the decontamination of nickel by radio contaminants such as technetium and actinides.

A method of coating a copper substrate comprises the steps of: anodically microsmoothing the copper substrate in an acid bath to provide a substantially smooth surface; electrocoating the microsmoothed substrate with a pin hole free nickel film having a thickness of between about 2.5 microns to about 12.5 microns; single step, non-aqueous electrocoating the microsmoothed, nickel coated substrate with a pin hole free polyamic acid polymer, and curing the polyamic acid coating to form a polyimide film free of copper ion contamination.

Method for coating of polyimide by electrodeposition

A metal article is produced by: (1) providing an aluminum master substrate, the surface of which may be smooth or patterned; (2) making the aluminum master substrate cathodic, in an acid or acid salt solution which will not etch aluminum, at a current density of between about 10 to 500A/sq. ft., at solution temperatures of up to about 50.degree.C; (3) coating the surface of the aluminum master substrate with a thin metal layer and (4) dissolving the aluminum master substrate, to provide a metal foil article that is a negative duplicate of the smooth or patterned aluminum master substrate surface.

Growing community of inventors

Plum Boro, PA, United States of America

William R Gass