Methods for simultaneous leaching and extraction of precious metals

Patent metadata

Field	Value
Publication number	US-2018142322-A1
Application number	US-201615568245-A
Country	US
Kind code	A1
Filing date	Apr 21, 2016
Priority date	Apr 21, 2015
Publication date	May 24, 2018
Grant date	—

Abstract

The present applications relates to methods for the simultaneous leaching and extraction of precious metals. For example, the present application relates to methods of leaching and extracting gold and/or palladium from a substance comprising gold and/or palladium such as a gold- and/or palladium-containing ore in one step using a compound of Formula I:(I).

First claim

1 . A method of leaching and extracting gold and/or palladium from a substance comprising gold and/or palladium, the method comprising:
treating a mixture comprising an aqueous phase comprising an acid, an oxidizing agent and the substance, and an organic phase comprising a water-immiscible organic solvent and a compound of Formula I:

wherein
R 1 is —NR 4 R 5 or aryl;
R 2 and R 3 are each independently selected from H, C 1-10 alkyl, C 3-10 cycloalkyl, C 1-6 alkyleneC 3-10 cycloalkyl, heterocycloalkyl and aryl; or
R 2 and R 3 together with the nitrogen atom to which they are attached, form a heterocycloalkyl or a heteroaryl, or a heterocycloalkyl or a heteroaryl substituted at one or more carbon atoms with C 1-4 alkyl;
R 4 and R 5 are each independently selected from H, C 1-10 alkyl, C 3-10 cycloalkyl, C 1-6 alkyleneC 3-10 cycloalkyl, heterocycloalkyl and aryl; or
R 4 and R 5 together with the nitrogen atom to which they are attached, form a heterocycloalkyl or a heteroaryl, or a heterocycloalkyl or a heteroaryl substituted at one or more carbon atoms with C 1-4 alkyl;
X is O or S;
Y is S, NR 6 or CR 6 R 7 ; and
R 6 and R 7 are each independently selected from H, C 1-10 alkyl, C 3-10 cycloalkyl, C 1-6 alkyleneC 3-10 cycloalkyl, heterocycloalkyl and aryl,

under conditions to leach the gold and/or palladium from the substance and extract the gold and/or palladium by forming a complex between the leached gold and/or palladium and the compound of Formula I, in one step.

2 . The method of claim 1 , wherein the compound of Formula I is a compound of Formula I(a):

wherein R 2 , R 3 , R 4 , R 5 and Y are as defined in claim 1 .

3 . The method of claim 2 , wherein only one of R 2 , R 3 , R 4 and R 5 is H.

4 . The method of claim 2 , wherein R 2 and R 3 together with the nitrogen atom to which they are attached form a heterocycloalkyl or a substituted heterocycloalkyl, wherein the heterocycloalkyl is selected from aziridinyl, azetidinyl, pyrrolidinyl, piperidinyl, azepanyl, azocanyl, imidazolidinyl, oxazolidinyl, thiazolidinyl, piperazinyl, hexahydropyrimidinyl, morpholinyl, 1,3-oxazinanyl, thiomorpholinyl, 1,3-thiazinanyl, 1,3-diazepanyl, 1,3-oxazepanyl, 1,3-thiazepanyl, 1,4-diazepanyl, 1,4-oxazepanyl, 1,4-thiazepanyl, 1,3-diazocanyl, 1,3-oxazocanyl, 1,3-thiazocanyl, 1,4-diazocanyl, 1,4-oxazocanyl, 1,4-thiazocanyl, 1,5-diazocanyl, 1,5-oxazocanyl and 1,5-thiazocanyl.

5 . (canceled)

6 . The method claim 2 , wherein R 4 is H and R 5 is C 1-6 alkyl or C 3-8 cycloalkyl.

7 . The method of claim 1 , wherein Y is NR 6 .

8 . The method of claim 7 , wherein R 6 is H, C 1-6 alkyl or C 3-8 cycloalkyl.

9 . The method of claim 1 , wherein the compound of Formula I is a compound of Formula I(a)(i), I(a)(ii), I(a)(iii) or I(a)(iv):

10 . (canceled)

11 . (canceled)

12 . The method of claim 1 , wherein the molar ratio of the compound of Formula I to the gold and/or palladium is about 3:1 to about 4:1.

13 . The method of claim 1 , wherein the acid is HCl having a concentration in the aqueous solution of about 1 M to about 2 M.

14 . The method of claim 1 , wherein the oxidizing agent is HNO 3 having a concentration in the aqueous solution of about 0.1 M to 1.0 M.

15 . The method of claim 1 , wherein the water-immiscible organic solvent is selected from dichloromethane, chloroform and chlorobenzene.

16 . The method of claim 1 , wherein the conditions to leach the gold and/or palladium from the substance and extract the gold and/or palladium by forming a complex between the leached gold and/or palladium and the compound of Formula I in one step comprise stirring the mixture for a time of about 2 hours to about 10 hours at a temperature of about 10° C. to about 40° C.

17 . The method of claim 1 , wherein the method further comprises separating the mixture into an aqueous phase and an organic phase comprising the complex between the leached gold and/or palladium and the compound of Formula I.

18 . The method of claim 17 , wherein the method further comprises stripping the gold and/or palladium from the complex between the compound of Formula I and the leached gold and/or palladium by a method comprising contacting the organic phase with an aqueous solution comprising an acid and thiourea under conditions to obtain a gold and/or palladium-containing strip solution and a gold and/or palladium-reduced organic phase comprising the compound of Formula I.

19 . The method of claim 18 , wherein the method further comprises separating the gold and/or palladium-containing strip solution from the gold and/or palladium-reduced organic phase comprising the compound of Formula I and recovering gold and/or palladium from the gold and/or palladium-containing strip solution by electrowinning or reduction.

20 . The method of claim 18 , wherein the method further comprises recycling the compound of Formula I from the gold and/or palladium-reduced organic phase.

21 . The method of claim 17 , wherein the method further comprises recovering gold and/or palladium from the organic phase by direct reduction.

22 . The method of claim 1 , wherein the substance comprising gold and/or palladium is a gold-containing ore.

23 . (canceled)

24 . (canceled)

25 . (canceled)

26 . (canceled)

27 . (canceled)

28 . The method of claim 1 , wherein the method further comprises, prior to contacting with the mixture, crushing and/or grinding the substance comprising gold and/or palladium into particles.

29 . (canceled)

30 . (canceled)

Assignees

• Univ Saskatchewan

Inventors

• Foley Stephen
• Salimi Hiwa
• Moradi Loghman

Classifications

• C22B3/16

  in organic solutions · CPC title

• C22B11/04 Primary

  by wet processes (extraction of metal compounds by leaching in organic solutions C22B3/16; treatment or purification of solutions by liquid-liquid extraction C22B3/26) · CPC title

• C07D295/215

  Radicals derived from nitrogen analogues of carbonic acid · CPC title

• C25C7/06

  Operating or servicing · CPC title

• C07D207/06

  with radicals, containing only hydrogen and carbon atoms, attached to ring carbon atoms · CPC title