Methods for rapidly leaching chalcopyrite

Patent metadata

Field	Value
Publication number	US-10407753-B2
Application number	US-201515535000-A
Country	US
Kind code	B2
Filing date	Dec 21, 2015
Priority date	Dec 19, 2014
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

A method of improving leach kinetics and recovery during atmospheric or above-atmospheric leaching of a metal sulfide is disclosed. A system for practicing the aforementioned method is also disclosed. Apparatus for practicing the aforementioned method is also disclosed. A new composition of matter which is formed by the aforementioned method, and which may be utilized in the system and apparatus is further disclosed. The new composition of matter may exhibit improved leach kinetics, and may have some utility in the semi-conductor arts, including uses within photovoltaic materials.

First claim

We claim:

1. A method of improving leach kinetics or metal recovery from a metal sulfide comprising:
exchanging iron in the metal sulfide for copper according to the following reaction stoichiometry:
Cu a Fe b S c +x Cu 2+ Cu a+x Fe b−(x+w) S c−w +( x+w )Fe 2+
wherein a is equal to one, b is equal to one, c is equal to two, x is equal to or less than 0.10, and the molar amount of iron (x+w) released from the Cu a Fe b S c exceeds the molar amount x of copper absorbed by the Cu a Fe b S c ,

wherein charge neutrality is maintained by producing an anion to balance the w amount of released iron,
wherein a ratio of the molar amount (x+w) of iron released from the Cu a Fe b S c to the molar amount x of copper absorbed by the Cu a Fe b S c is 1.2 to 1.94.

2. The method according to claim 1 , wherein the extent of conversion of the metal sulfide is calculated by the ratio (x/a).

3. The method according to claim 1 , wherein the anion is produced by oxidizing sulfide atoms within a lattice of the metal sulfide.

4. The method according to claim 1 , wherein the product Cu a+x Fe b−(x+w) S c−w is deficient in sulfide as well as iron, and differs in unit cell structure from chalcopyrite and covellite.

5. The method according to claim 1 , wherein the product Cu a+x Fe b−(x+w) S c−w comprises an intermediate phase which is metastable and transitionary between chalcopyrite and covellite.

6. The method according to claim 1 , further comprising oxidatively leaching the product Cu a+x Fe b−(x+w) S c−w at atmospheric pressure.

7. The method according to claim 1 , further comprising oxidatively leaching the product Cu a+x Fe b−(x+w) S c−w at a pressure above atmospheric pressure.

8. A method of activating a material containing chalcopyrite, comprising treating the material with copper sulfate under reducing conditions, and at least partially converting a portion of the material to a non-stoichiometric, iron-depleted copper sulfide specie according to the following reaction stoichiometry:
(CuFeS 2 ) n •3{Cu + Fe 3+ (S 2− ) 2 }+3Cu 2+ →3Fe 2+ +(CuFeS 2 ) n •2{(Cu + ) 3 (S 2 2− )(S •− )}

wherein n+3 is the total number of unit cells of (CuFeS 2 ) n •3{Cu + Fe 3+ (S 2− ) 2 } within a particle of the material;
wherein n is the number of unit cells of CuFeS 2 contained within (CuFeS 2 ) n •3{Cu + Fe 3+ (S 2− ) 2 } which remain unreacted by the copper sulfate, and
wherein superscript • appearing after S denotes an electron hole.

9. The method according to claim 8 , wherein treating the material with copper sulfate under reducing conditions is performed in the presence of chloride.

10. The method according to claim 8 , wherein treating the material with copper sulfate under reducing conditions is performed in the absence of chloride.

11. The method according to claim 8 , wherein treating the material with copper sulfate under reducing conditions comprises a diffusion-controlled, solid-state reaction process.

12. A composition of matter formed via the method according to claim 1 , comprising a non-stoichiometric, iron-depleted copper sulfide material which exhibits higher electrochemical reactivity than chalcopyrite.

13. A method of chemically activating a material containing chalcopyrite comprising the step of:
treating the material with cupric solution under reducing conditions to at least partially convert a portion of the material to a new material according to the following reaction:
(CuFeS 2 ) n •3{Cu + Fe 3+ (S 2− ) 2 }+3Cu 2+ →3Fe 2+ +(CuFeS 2 ) n •2{(Cu + ) 3 (S 2 2− )(S •− )}

wherein n+3 is the total number of unit cells of (CuFeS 2 ) n •3{Cu + Fe 3+ (S 2− ) 2 } within a particle of the material;
wherein n is the number of unit cells of CuFeS 2 contained within (CuFeS 2 ) n •3{Cu + Fe 3+ (S 2− ) 2 } which remain unreacted by the cupric solution, and
wherein superscript • appearing after S denotes an electron hole.

14. The method of claim 13 , further comprising the step of oxidatively leaching the treated chalcopyrite-containing material.

15. The method according to claim 13 , wherein the treated chalcopyrite-containing material comprises a non-stoichiometric, iron-depleted copper sulfide material.

16. The method according to claim 13 , wherein the new material comprises a non-stoichiometric, iron-depleted copper sulfide material.

17. The method according to claim 13 , wherein the new material is metastable.

18. The method according to claim 17 , wherein the new material is transitory.

19. The method according to claim 17 , wherein the new material is an intermediate phase that is transitionary between chalcopyrite and covellite.

20. A composition of matter formed via the method according to claim 8 , comprising a non-stoichiometric, iron-depleted copper sulfide material which exhibits higher electrochemical reactivity than chalcopyrite.

Assignees

• Smidth As F L
• Chaiko David J

Inventors

• Chaiko David J
• Rocks Sara (Sally)

Classifications

• C22B15/00

  Obtaining copper · CPC title

• C22B3/04

  by leaching (C22B3/18 takes precedence) · CPC title

• C22B15/0071 Primary

  containing sulfur · CPC title

• C01G49/14

  Sulfates {(C01G49/0018 takes precedence)} · CPC title

• C22B4/04

  Heavy metals {(C22B4/005 takes precedence)} · CPC title