# US 2019/0169038 A1 · Process For The Conversion Of Lithium Phosphate Into A Low Phosphate Lithium Solution Suitable As Feedstock For The Production Of Saleable Lithium Products And For The Recovery Of Phosphorous For Re-Use In The Production Of Lithium Phosphate

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- Number: US 2019/0169038 A1
- Document ID: US20190169038A1
- Status: Published application
- Kind: A1
- Application number: 16/324,065
- Filed: 2017-08-08
- Published: 2019-06-06
- Earliest claimed: 2016-08-08
- Assignees: Lithium Extraction Technologies (Australia) Pty Lt D; Australian Nuclear Science and Technology Organisation
- Applicants: Lithium Extraction Technologies (Australia) Pty Ltd; Australian Nuclear Science and Technology Organisation
- Inventors: Cameron STANTON; John LAWSON; Paul FREEMAN; Suzanne BURLING
- Web page: https://patentgrep.com/patent/US20190169038A1

## CPC

- C01D 15/02: Oxides; Hydroxides
- C01B 25/308: {Methods for converting an alkali metal orthophosphate into another one; Purification; Decolorasing; Dehydrating; Drying}
- C01B 25/34: Magnesium phosphates
- C01B 25/37: Phosphates of heavy metals
- C01B 25/375: {of iron}
- C01D 15/08: Carbonates; Bicarbonates
- C01F 5/22: from magnesium compounds with alkali hydroxides or alkaline- earth oxides or hydroxides
- C01G 49/02: Oxides; Hydroxides {(C01G49/0018 takes precedence)}
- C22B 3/06: in inorganic acid solutions {, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions}
- C22B 3/10: Hydrochloric acid {, other halogenated acids or salts thereof}
- C22B 3/44: by chemical processes (treatment or purification of solutions by liquid-liquid extraction C22B3/26, by ion-exchange extraction C22B3/42)
- C22B 26/12: Obtaining lithium
- Y02P 10/20: Recycling
- C01D: COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; sulfides C01B17/22; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds other than ammonia and cyanogen, containing nitrogen and other non-metals C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; phosphides C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; cyanides C01C3/08; salts of cyanic acid C01C3/14; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C01F: COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; sulfides or polysulfides of magnesium, calcium, strontium, or barium C01B17/42; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds other than ammonia or cyanogen containing nitrogen and non-metals and optionally metals C01B21/082; amides or imides of silicon C01B21/087}; metal {imides or} amides C01B21/092, {C01B21/0923}; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanic acid C01C3/14; salts of cyanamide C01C3/16; thiocyanates C01C3/20; {double sulfates of magnesium with sodium or potassium C01D5/12; with other alkali metals C01D15/00, C01D17/00})
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

Some aspects of the present disclosure relate to systems and processes for the conversion of lithium phosphate into a low-phosphate solution containing lithium which may be suitable as feedstock for the production of saleable lithium products.

## Claims

### Claim 1

A process for converting lithium phosphate into a low-phosphate solution containing lithium which is suitable as feedstock for the production of saleable lithium products, the process comprising:
dissolving the lithium phosphate in acid to form an acidic lithium phosphate bearing solution;
treating the acidic lithium phosphate bearing solution with a hydroxide of a phosphate carrier to form a precipitate of phosphate and the phosphate carrier; and
separating the precipitate of phosphate and the phosphate carrier leaving a low-phosphate solution containing lithium.

### Claim 2 (depends on 1)

The process of claim 1, further comprising: treating the precipitate of phosphate and the phosphate carrier with a hydroxide base to convert the phosphate carrier to a precipitate of hydroxide and the phosphate carrier.

### Claim 3

(canceled)

### Claim 4 (depends on 2)

The process of claim 2, wherein the treatment with the hydroxide base is carried out at a temperature higher than ambient temperature.

### Claim at position 5

5-7. (canceled)

### Claim 8 (depends on 2)

The process of claim 2, wherein the treatment with the hydroxide base is carried out at an acidic pH.

### Claim at position 7

9-12. (canceled)

### Claim 13 (depends on 2)

The process of claim 2, wherein the treatment with the hydroxide base is carried out in two stages.

### Claim 14 (depends on 13)

The process of claim 13, wherein the first stage and/or the second stage of treatment with the hydroxide base are carried out at a temperature higher than ambient temperature.

### Claim 15 (depends on 13)

The process of claim 13, wherein the first stage and/or the second stage of treatment with the hydroxide base are carried out at a temperature about 70° C. to about 200° C.

### Claim at position 11

16-17. (canceled)

### Claim 18 (depends on 13)

The process of claim 13, wherein the first stage and/or the second stage of treatment with the hydroxide base are carried out at an acidic pH.

### Claim 19 (depends on 13)

The process of claim 13, wherein the first stage and/or the second stage of treatment with the hydroxide base are carried out at a pH<2.75.

### Claim 20

(canceled)

### Claim 21 (depends on 13)

The process of claim 13, wherein the pH in the second stage is controlled to a pH greater than the pH of the first stage.

### Claim 22

(canceled)

### Claim 23 (depends on 2)

The process of claim 2, wherein treating the precipitate of phosphate and the phosphate carrier with a hydroxide base releases the phosphate into solution for re-use in a process to produce lithium phosphate.

### Claim 24 (depends on 2)

The process of claim 2, wherein the precipitate of hydroxide and the phosphate carrier is separated and at least some of the phosphate carrier is re-used in the step of treating the acidic lithium phosphate bearing solution to form the precipitate of phosphate and the phosphate carrier.

### Claim 25 (depends on 2)

The process of claim 2, wherein the precipitate of hydroxide and the phosphate carrier is separated and at least some of the phosphate carrier is dissolved in acid to form a solution of the phosphate carrier ion.

### Claim 26 (depends on 25)

The process of claim 25, wherein the solution of the phosphate carrier ion is used to treat a solution containing residual phosphate from which the lithium phosphate has been separated prior to being dissolved in acid whereby the phosphate carrier forms a precipitate of the residual phosphate and the phosphate carrier.

### Claim 27 (depends on 26)

The process of claim 26, wherein the solution containing residual phosphate is a brine and the precipitate of the residual phosphate and the phosphate carrier is separated from the brine, thereby leaving the brine substantially phosphate free for return to the environment.

### Claim 28 (depends on 27)

The process of claim 27, wherein the precipitate of the residual phosphate and the phosphate carrier separated from the brine is treated with the hydroxide base.

### Claim 29 (depends on 1)

The process of claim 1, wherein the phosphate carrier comprises an ion that forms an insoluble phosphate compound within a certain pH range and that releases the phosphate and forms an insoluble hydroxide compound at a higher pH.

### Claim 30 (depends on 1)

The process of claim 1, wherein the phosphate carrier ion is iron (lll).

### Claim 31 (depends on 1)

The process of claim 1, wherein the phosphate carrier ion is magnesium (II).

### Claim 32

(canceled)

### Claim 33 (depends on 1)

The process of claim 1, wherein the phosphate carrier ion is an ion of a rare earth element.

### Claim at position 28

34-38. (canceled)