RECOVERY OF RARE EARTHS FROM CONCENTRATES CONTAINING FLUORINE

• US 20180209015A1
• Filed: 07/21/2016
• Published: 07/26/2018
• Est. Priority Date: 07/21/2015
• Status: Active Grant

• Current Assignee: Hazen Research, Inc.
• Original Assignee: Hazen Research, Inc.
• Inventors: SUN, Kang, BAUGHMAN, David R., HAZEN, Wayne W.
• Granted Patent: US 10,640,847 B2
• Time in Patent Office: Days
• CPC Class Codes: C01F 17/271 Chlorides
• CPC Class Codes: C01F 5/32 Preparation of anhydrous magnesium chloride by chlorinating magnesium compounds
• CPC Class Codes: C01G 23/02 Halides of titanium
• CPC Class Codes: C01G 23/04 Oxides; Hydroxides
• CPC Class Codes: C01G 25/02 Oxides
• CPC Class Codes: C01G 25/04 Halides
• CPC Class Codes: C22B 1/08 Chloridising roasting
• CPC Class Codes: C22B 1/16 Sintering; Agglomerating
• CPC Class Codes: C22B 3/10 Hydrochloric acid , other halogenated acids or salts thereof
• CPC Class Codes: C22B 34/12 Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
• CPC Class Codes: C22B 34/1245 containing a halogen ion as active agent
• CPC Class Codes: C22B 34/14 Obtaining zirconium or hafnium treatment or purification of solutions by liquid-liquid extraction, by ion exchange or by adsorption C22B3/00, C01G25/003, C01G27/003
• CPC Class Codes: C22B 34/24 Obtaining niobium or tantalum
• CPC Class Codes: C22B 59/00 Obtaining rare earth metals
• CPC Class Codes: Y02P 10/20 Recycling

Abstract

The present invention relates to the recovery of rare earths, scandium, niobium, tantalum, zirconium, hafnium, titanium, and the like from ores or concentrates containing fluorine. More specifically, the ores or concentrates are pretreated by carbochlorination to convert the rare earths and other metals into their chlorides and then subjected to dilute hydrochloric acid leaching to recover the valuable rare earths and other metals from the leachate. Niobium, tantalum, zirconium, hafnium, and titanium can be recovered as their chlorides or oxychlorides from the gaseous products of carbochlorination, or converted into their oxides while simultaneously regenerating chlorine.

Claims

1. A method of recovering a mineral from a fluorine-containing ore or concentrate, the method comprising:

treating the fluorine-containing ore or concentrate by carbochlorination in the presence of a carbon-containing material and a fluorine capturing agent to form a mineral chloride and a treated ore or concentrate, wherein a partial pressure or activity of the fluorine capturing agent substantially prevents formation of rare earth fluorides throughout the treating step;

contacting the treated ore or concentrate with a dilute HCl leach solution to solubilize the mineral chloride in the leach solution; and

recovering the mineral,

wherein the mineral is selected from the group consisting of a rare earth mineral, a scandium mineral, a niobium mineral, a tantalum mineral, a zirconium mineral, a hafnium mineral, a titanium mineral, and combinations thereof.

2. The method of claim 1, wherein the fluorine capturing agent comprises at least one of magnesium chloride, silicon tetrachloride, and mixtures thereof.

3. The method of claim 2, wherein the fluorine capturing agent comprises at leason one of (i) silicon tetrachloride formed in situ during the treating step by carbochlorination of silicon dioxide or silicates, and (ii) magnesium chloride formed in situ during the treatin gstep by carbochlorination of at least one of magnesium oxide, magnesium hydroxide, and magnesium carbonate.

5. The method of claim 1, wherein the fluorine-containing ore or concentrate comprises at least one of monazite, bastnä

site, pyrochlore, zircon, ilmenite, rutile, loparite, columbite, and tantalite.

6. The method of claim 1, wherein a weight ratio of the fluorine-containing ore or concentrate to the carbon-containing material is less than about 5:

1.

7. The method of claim 1, wherein the treating step is performed for a time of between about two hours and about four hours.

8. The method of claim 1, wherein the treating step is performed at a temperature of between about 600°

C. and about 1000°

C.

9. The method of claim 1, wherein the mineral is recovered from the leach solution.

11. The method of claim 1, wherein the mineral is recovered from a gas phase.

13. The method of claim 1, wherein the carbon-containing material comprises at least one of coke, coal, biomass, and an organic compound.

4. (canceled)

10. (canceled)

12. (canceled)

14. A method of recovering a mineral comprising at least one of scandium, niobium, tantalum, zirconium, hafnium, titanium, and a rare earth element from a fluorine-containing ore or concentrate, comprising:

(a) agglomerating the fluorine-containing ore or concentrate with a carbon-containing material, a fluorine capturing agent, and a binder to produce an agglomerate;

(b) carbochlorinating the agglomerate by exposing the agglomerate to chlorine gas to produce a calcine;

(c) leaching the calcine by contacting the calcine with a dilute hydrochloric acid solution having a pH of less than about 4.0 to produce a mixture of a liquid and a solid; and

(d) recovering the mineral by contacting the liquid of the mixture with at least one of sodium hydroxide, ammonium hydroxide and magnesium hydroxide,

wherein a partial pressure or activity of the fluorine capturing agent substantially prevents formation of rare earth fluorides throughout step (a).

15. The method of claim 14, wherein step (b) produces a gas, further comprising:

(e) condensing the gas to produce at least one of condensed chlorides and oxychlorides; and

(f) regenerating chlorine gas by exposing the at least one of chlorides and oxychlorides to an oxygen-containing gas.

16. The method of claim 15, wherein the chlorine gas regenerated in step (f) is at least part of the chlorine gas to which the agglomerate is exposed in step (b).

17. The method of claim 14, wherein the fluorine capturing agent comprises at least one of magnesium chloride, silicon tetrachloride, and mixtures thereof.

18. The method of claim 17, wherein the fluorine capturing agent comprises at least one of (i) silicon tetrachloride formed in situ during step (b) by carbochlorination of silicon dioxide or silicates, and (ii) magnesium chloride formed in situ during step (b) by carbochlorination of at least one of magnesium oxide, magnesium hydroxide, and magnesium carbonate.

20. The method of claim 14, wherein the fluorine-containing ore or concentrate comprises at least one of monazite, bastnasite, pyrochlore, zircon, ilmenite, rutile, loparite, columbite, and tantalite.

21. The method of claim 14, wherein a weight ratio of the ore or concentrate to the carbon-containing material is less than about 5:

1.

22. The method of claim 14, wherein step (b) is performed for a time of between about two hours and about four hours.

23. The method of claim 14, wherein step (b) is performed at a temperature of between about 600°

C. and about 1000°

C.

24. The method of claim 14, wherein the carbon-containing material comprises at least one of coke, coal, biomass, and an organic compound.

19. (canceled)