IRON CHELATORS AS ACTIVATORS IN ALKALINE FLOTATION CIRCUITS

Abstract

The present invention is directed to a method for selectively recovering a mineral from an ore applying a promoter being a substituted ethylene diamine. Further, the present invention is directed to the use of said substituted polymeric alkylenediamine to separate a target mineral from an ore.

Claims

1. A method for selectively recovering a mineral from an ore, comprising: i) grinding the ore, ii) preparing a pulp of the ground ore obtained in step i), iii) adding at least one promoter comprising at least one substituted polymeric alkylene diamine to the pulp obtained in step ii), and iv) subjecting the pulp containing the at least one promoter obtained in step iii) to froth flotation.

2. The method according to claim 1, wherein the pH value of the pulp is adjusted to a range of 8.0 to 12.0.

3. The method according to claim 1, wherein the concentration of the at least one promoter within the pulp is in the range of 5 to 250 g/t.

4. The method according to claim 1, wherein the at least one substituted polymeric alkylene diamine is of formula (I) ##STR00022## wherein R.sup.1 and R.sup.2 are independently from each other a polyalkyleneimine moiety B or a salt thereof comprising at least one pendant group Z, R.sup.3 and R.sup.4 are independently from each other a pendant group Z, Z is an alkyl, heteroalkyl, aryl, alkylaryl or arylalkyl group comprising at least one moiety Y, and Y is a carboxylate (—COOR.sup.5), sulfonate (—SO.sub.3R.sup.6), sulfate (—O—SO.sub.3R.sup.7), phosphonate (—P(═O)(OR.sup.8)(OR.sup.9)), phosphate (—O—P(═O)(OR.sup.10)(OR.sup.11)), carboxylic acid (—COOH), sulfonic acid (—SO.sub.3H), phosphonic acid (—P(═O)(OH).sub.2), phosphoric acid (—O—P(═O)(OH).sub.2) moiety, or their deprotonated forms, R.sup.5, R.sup.6 and R.sup.7 are independently from each other H, alkyl, aryl, alkylaryl or arylalkyl, Li, Na or K, R.sup.8 and R.sup.10 are independently from each other alkyl, aryl, alkylaryl or arylalkyl, R.sup.9 and R.sup.11 are independently from each other H, alkyl, aryl, alkylaryl or arylalkyl, and q is an integer from 0 to 5.

5. The method according to claim 4, wherein the pendant group Z is independently from each other the pendant group Z1 ##STR00023## or the pendant group Z2 ##STR00024## wherein m is an integer from 1 to 15, r is an integer from 2 to 15, and p is an integer from 1 to 15.

6. The method according to claim 4, wherein the polyalkyleneimine moiety B or salt thereof is a polyethyleneimine moiety B or salt thereof.

7. The method according to claim 4, wherein the polyalkyleneimine moiety B is of formula (B) ##STR00025## wherein Z is independently from each other Z1 or Z2, and n is in the range of 1 to 300.

8. The method according to claim 4, wherein the at least one substituted polymeric alkylene diamine is a substituted polymeric ethylene diamine of formula (I) wherein at least one of R.sup.1 or R.sup.2 is ##STR00026## wherein Z is independently from each other Z1 or Z2, n is in the range of 1 to 300, q is 0, and R.sup.3 and R.sup.4 have the same meaning as Z.

9. The method according to claim 4, wherein Y is a carboxylate (—COOR.sup.5).

10. The method according to claim 9, wherein the substituents R.sup.5 are independently from each other H, Li, Na or K.

11. The method according to claim 4, wherein the pendant group Z is independently from each other the pendant group Z1′ ##STR00027## or the pendant group Z2′ ##STR00028## wherein the substituents R.sup.5 are independently from each other H, Li, Na or K.

12. The method according to claim 11, wherein the substituents R.sup.5 are independently from each other H or Na.

13. The method according to claim 12, wherein 90 to 100 mol-% of the substituents R.sup.5 are Na.

14. The method according to claim 4, wherein the at least one substituted polymeric alkylene diamine is a substituted polymeric ethylene diamine of formula (IIb) ##STR00029## wherein the substituents R.sup.5 are independently from each other H or Na and 90 to 100 mol-% of the substituents R.sup.5 are Na.

15. The method according to claim 1, wherein the pulp further comprises at least one collector.

16. The method according to claim 15, wherein the collector is selected from the group consisting of xanthates, dithiophosphates, thionocarbamates, dithiocarbamates, xantoformiates, xanthate esters, dithiophosphates, monothiophosphates, dithiophosphinates, hydroxamic acids and their alkali metal or ammonium salts, alkyl-, alkenyl- and arylphosphonic acids and salts thereof, phosphoric acid mono- and diesters with long chain alcohols or alcoxylated alcohols and salts thereof, mixtures of the collectors mentioned above with fatty acids and their salts, and mixtures thereof.

17. The method according to claim 1, wherein the pulp further comprises at least one frother.

18. The method according to claim 1, wherein the ore comprises gold, copper or iron or a combination thereof.

19. A method of using the promoter of claim 1 to separate a target mineral from an ore.

20. The method Use-according to claim 19, wherein the target mineral contains gold or copper.

Description

EXAMPLES

[0190] A Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) from Q-Sense, was used to demonstrate the use of inventive flotation promoters to improve the adsorption of collector onto the surface of gold previously exposed to iron salts.

[0191] Comparative example: a gold plate was contacted with Mili-Q water at pH=7 for 30 minutes. A solution of 10 mmol/L FeCl.sub.3 was circulated though the QCM-D to allow deposition of Fe on the gold plate. Milli-Q water was circulated again for 30 minutes to rinse the excess salts not adsorbed onto the gold plate. A solution of 1% Diethyl dithiophosphate ammonium salt (Sigma-Aldrich, CAS 1068-22-0) at pH=11 was circulated for 60 minutes. A final rinse with Mili-Q water at pH=11 was conducted for 60 minutes. The Mass change in ng/cm.sup.2 was continuously recorded during the experiment.

[0192] The inventive promoter DP-OMC-1127 is a commercially available polyethyleneimine by BASF having a molecular weight of 50,000 g/mol and a degree of substitution of 80%. DP-OMC-1127 is represented by the below formula:

##STR00021##

[0193] Inventive example: a gold plate was contacted with Mili-Q water at pH=7 for 30 minutes. A solution of 10 mmol/L FeCl.sub.3 was circulated though the QCM-D to allow deposition of Fe on the gold plate. Milli-Q water was circulated again for 30 minutes to rinse the excess salts not adsorbed onto the gold plate. A solution of 1% DP-OMC-1127 (BASF) at pH=11 was circulated for 60 minutes. Milli-Q water was circulated again for 30 minutes as rinsing step for the non-adsorbed DP-OMC-1127. A solution of 1% Diethyl dithiophosphate ammonium salt (Sigma-Aldrich, CAS 1068-22-0) at pH=11 was circulated for 60 minutes. A final rinse with Mili-Q water at pH=11 was conducted for 60 minutes. The Mass change in ng/cm.sup.2 was continuously recorded during the experiment.

[0194] The comparative and inventive example results are summarized in Tables 1 and 2.

TABLE-US-00001 TABLE 1 Comparative example results. Mass Change [ng/cm.sup.2] Step Solution pH Run 1 Run 2 1 Water 7 0 0 2 10 mmol/L FeCl.sub.3 3 311 243 3 Water 11 340 261 4 1% Dithiophosphate 11 312 240 Mass of Dithiophosphate Adsorbed [ng] 1 −3

TABLE-US-00002 TABLE 2 Inventive example results. Mass Change [ng/cm.sup.2] Step Solution pH Run 3 Run 4 1 Water 7 0 0 2 10 mmol/L FeCl.sub.3 3 390 513 3 Water 11 409 533 4 1% DP-OMC-1127 11 440 460 5 Water 11 445 371 6 1% Dithiophosphate 11 502 413 Mass of Dithiophosphate Adsorbed [ng] 57 42

[0195] As shown in Tables 1 and 2, the application of the inventive promoter DP-OMC-1127 after the exposure of the gold surface to FeCl.sub.3 allow the deposition of collector Diethyl dithiophosphate which was not detected in the comparative experiment without the promoter.

[0196] The results obtained showed that the addition of the inventive promoter resulted in improvement in the adsorption of collector onto gold surfaces.