# US 4,397,820 A · Method to maintain a high Fe.sup.+2 /Fe.sup.+3 ratio in the stripping system for the recovery of uranium from wet process phosphoric acid

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- Number: US 4,397,820 A
- Document ID: US4397820A
- Status: Granted
- Kind: A
- Application number: 06/171,699
- Filed: 1980-07-24
- Granted: 1983-08-09
- Earliest claimed: 1980-07-24
- Assignees: Wyoming Mineral Corporation
- Inventors: Regis R. Stana; Jose G. Lopez
- Web page: https://patentgrep.com/patent/US4397820A

## CPC

- C22B 60/0282: {Solutions containing P ions, e.g. treatment of solutions resulting from the leaching of phosphate ores or recovery of uranium from wet-process phosphoric acid}
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS

## Abstract

A process to maintain a high iron +2/iron +3 concentration in the reductive stripping system for recovering uranium from wet-process phosphoric acid, comprises contacting partially oxidized strip acid, containing substantial amounts of iron +3, which had just previously stripped uranium values from an organic solvent, with elemental iron to reduce iron +3 to iron +2 and provide a Fe.sup.+2 /Fe.sup.o conversion ratio of from about 1.5 to 3.0.

## Claims

### Claim 1

In the method of recovering uranium from wet-process phosphoric acid comprising the following steps:
(1) passing acid solution containing uranium through an extractor to provide uranium rich solvent and raffinate acid,
(2) contacting part of the raffinate acid with elemental iron to produce reduced acid containing iron +2, and
(3) stripping uranium rich solvent with the reduced acid in a reductive stripper system comprising at least one stripper, wherein part of the iron in the acid is oxidized to form partially oxidized acid, said partially oxidized acid containing substantial amounts of iron +3 after stripping; the improvement comprising contacting the iron +3 contained in the partially oxidized acid formed in step (3) with elemental iron powder added directly to at least one stripper of said reductive stripper system, the reduce iron +3 to iron +2.

### Claim 2 (depends on 1)

The method of claim 1, wherein the elemental iron power added has a particle size range of between about 354 microns diameter the about 2.8 millimeters diameter, the primary reaction between the iron +3 and the elemental iron power in step (3) is: Fe.sup.o +2Fe.sup.+3 =3Fe.sup.+2 and the Fe.sup.+2 /Fe.sup.o conversion ratio in step (3) is from about 1.5 to 3.0.