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US 8,802,041 B1Granted
Decontamination of radioactive metals
AssigneeToxco, Inc.
InventorsW. Novis Smith, David S. Eaker
Life of this patent
Estimating the term…
Abstract
There is provided a process for decontaminating and converting volumetrically contaminated radioactive metals, especially nickel, and recovering a decontaminated metal hydroxide or metal carbonate. The process includes the use of hydrogen peroxide to oxidize and remove nucleotides.
Claims14
A process for the recovery of metals in a carbonate or hydroxide form from volumetrically contaminated radioactive metals, wherein the process comprises the steps of:
- A) dissolving the radioactive metals in an acid solution containing about 0.5 to about 2.0% by weight, based on the weight of radioactive metals, of an iron salt or iron oxide or combination thereof to obtain a first solution;
- B) neutralizing the first solution from step A) to a pH of about 4.5 to about 5 with at least one base to obtain a first slurry containing precipitated ferric hydroxide;
- C) treating the first slurry obtained in step B) with hydrogen peroxide, to oxidize any oxidizable nucleotides present, and with an alkali metal fluoride to obtain a second slurry;
- D) filtering the second slurry of step C) to remove the precipitated ferric hydroxide and any impurities absorbed on the precipitated ferric hydroxide and to obtain a filtrate;
- E) passing the filtrate from step D) through an anion exchange column maintained at a temperature of below about 35° C. so as to absorb nucleotides onto said anion exchange column to obtain an eluent;
- F) adjusting the pH of the eluent of step E) to a pH of from about 10 to about 11 with at least one base selected from the group consisting of alkali metal hydroxides and alkali metal carbonates to obtain a product;
- and
- G) filtering the product from step F) to recover metals in a carbonate or hydroxide form.
5 more elements
A process for the decontamination of radioactive nickel, wherein the process comprises the steps of:
- a) dissolving radioactive nickel particles in aqueous nitric acid under an inert atmosphere to obtain a first solution;
- b) adding 0.5 to about 2.0% by weight of ferric nitrate, based on the weight of radioactive nickel particles, to the first solution obtained in step a) to obtain a second solution;
- c) neutralizing the second solution from step b) with calcium hydroxide and at least one alkali metal hydroxide to a pH of about 4.5 to about 5 to obtain a first slurry containing precipitated ferric hydroxide;
- d) adding a solution of hydrogen peroxide to the first slurry obtained in step c) to oxidize any nucleotides present to obtain a second slurry;
- e) adding a solution of sodium fluoride to the second slurry to precipitate soluble calcium present in the second slurry to obtain a third slurry;
- f) filtering the third slurry of step e) to obtain a filtrate and passing the filtrate through a strong anion exchange column which has been conditioned and adjusted to a pH of 5 and a temperature below 35° C. to obtain an eluent;
- g) adjusting the eluent obtained in step f) with an alkali metal carbonate to a pH of from about 10 to about 11 to obtain a product;
- and
- h) filtering the product obtained in step g) to recover nickel carbonate.
6 more elements
Dependencies are inferred from the claim text.