# US 4,396,560 A · Process for the continuous removal of undesirable components of solid particles by a solvent applied in counterflow

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- Number: US 4,396,560 A
- Document ID: US4396560A
- Status: Granted
- Kind: A
- Application number: 06/207,027
- Filed: 1980-11-14
- Granted: 1983-08-02
- Earliest claimed: 1978-03-03
- Assignees: Gesellschaft zur Forderung der Forschung an der Eidgenossisschen Technischen Hochschule
- Inventors: Bernard Stofer
- Web page: https://patentgrep.com/patent/US4396560A

## CPC

- G21C 3/58: Solid reactor fuel {Pellets made of fissile material}
- B01D 11/0207: {Control systems}
- B01D 11/0242: {in towers, e.g. comprising contacting elements}
- Y02E 30/30: Nuclear fission reactors
- Y10S 422/903: Radioactive material apparatus
- G21C: NUCLEAR REACTORS (fusion reactors, hybrid fission-fusion reactors G21B; nuclear explosives G21J)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A cyclical and automatable process and apparatus for continuously removing undesired components from solid particles by means of a solvent, the process including maintaining an expanded bed of solid particles in a vertical column, supplying a suitable solvent to the bed to flow through the bed either upwardly or downwardly in a selectably alternating manner, supplying solid particles to the top of the column while the solvent flows upwardly therethrough and interrupting the supply of solid particles and removing a bottom portion of the bed by the solvent when it flows downwardly.

## Claims

### Claim 1

A process for the removal of undesirable soluble contaminants from solid particles by passing a solvent for the contaminants through a bed of the contaminated solid particles, the process comprising the following sequential steps:
(1) charging the contaminated solid particles into the upper end of a column of solvent by way of an upper decanter zone which has a greater diameter than that of the solvent column;
(2) adding solvent to the solvent column near its lower end and causing the solvent to move at a predetermined rate upwardly, thereby causing the contaminated solid particles in the solvent column to form an expanded bed,
(3) removing solvent with dissolved contaminants therein from the upper decanter zone,
(4) after a first predetermined time period has passed, stopping the charging of contaminated solid particles to the top of the solvent column and the adding of solvent to the base of the solvent column,
(5) adding solvent to the solvent column near its upper end and concurrently removing a section of the bed of solid particles from the lower end of the solvent column for a second predetermined time period,
(6) at the conclusion of said second predetermined time period, stopping both the supply of solvent to the upper end of the solvent column and the removal of solid particles from the lower end of the solvent column, and
(7) repeating steps (1)-(6).

### Claim 2 (depends on 1)

A process according to claim 1, wherein said solid particles are particles containing thorium, uranium or plutonium.

### Claim 3 (depends on 1)

A method according to claim 1, wherein said solid particles are gel-like.

### Claim 4 (depends on 1)

A method according to claim 1 wherein said solid particles are in the form of microspheres produced by a wet-chemical process.