# US 4,395,367 A · Process for treating fission waste

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- Number: US 4,395,367 A
- Document ID: US4395367A
- Status: Granted
- Kind: A
- Application number: 06/322,144
- Filed: 1981-11-17
- Granted: 1983-07-26
- Earliest claimed: 1981-11-17
- Inventors: Charles A. Rohrmann; Oswald J. Wick
- Web page: https://patentgrep.com/patent/US4395367A

## CPC

- C03C 1/002: {Use of waste materials, e.g. slags}
- C03C 3/089: containing boron
- C03C 8/04: containing zinc
- C03C 8/14: Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions
- G21F 9/007: {Recovery of isotopes from radioactive waste, e.g. fission products (separating different isotopes of the same chemical element B01D59/00)}
- G21F 9/305: {Glass or glass like matrix (C03B5/005 takes precedence; compositional aspects C03C)}
- C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- G21F: PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR (radiation protection by pharmaceutical means A61K8/00, A61Q17/04; in cosmonautic vehicles B64G1/54; combined with a reactor G21C11/00; combined with X-ray tubes H01J35/16; combined with X-ray apparatus H05G1/02)

## Abstract

A method is described for the treatment of fission waste. A glass forming agent, a metal oxide, and a reducing agent are mixed with the fission waste and the mixture is heated. After melting, the mixture separates into a glass phase and a metal phase. The glass phase may be used to safely store the fission waste, while the metal phase contains noble metals recovered from the fission waste.

## Claims

### Claim 1

A process for the treatment of fission waste comprising:
(a) mixing a glass forming agent, a scavenging metal oxide, and a reducing agent with said fission waste;
(b) melting said mixture and thereby forming a glass phase and a metal phase;
(c) separating the two phases; and
(d) cooling said glass phase and thereby forming a stable leach-resistant solid suitable for long-term storage of radioactive materials.

### Claim 2 (depends on 1)

The process of claim 1 wherein the glass forming agent comprises SiO.sub.2. B.sub.2 O.sub.3, Na.sub.2 CO.sub.3, CaO, or glass prepared therefrom.

### Claim 3 (depends on 1)

The process of claim 1 wherein the scavenging metal oxide is PbO, Bi.sub.2 O.sub.3, Sb.sub.2 O.sub.3, SnO, or CuO.

### Claim 4 (depends on 1)

The process of claim 1 wherein the reducing agent comprises Si or C.

### Claim 5 (depends on 1)

The process of claim 1 wherein said metal phase comprises scavenging metal and Pd, Rh, Ru, or Tc.

### Claim 6 (depends on 5)

The process of claim 5 wherein said Pd, Rh, Ru, or Tc is separated from said metal phase and the scavenging metal is oxidized and recycled to step (a).