WO2014105944A1 - Use of enzymes for recovering a metal from a metal-containing ore - Google Patents
Use of enzymes for recovering a metal from a metal-containing ore Download PDFInfo
- Publication number
- WO2014105944A1 WO2014105944A1 PCT/US2013/077790 US2013077790W WO2014105944A1 WO 2014105944 A1 WO2014105944 A1 WO 2014105944A1 US 2013077790 W US2013077790 W US 2013077790W WO 2014105944 A1 WO2014105944 A1 WO 2014105944A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- metal
- enzyme
- leaching
- leaching agent
- containing ore
- Prior art date
Links
- 108090000790 Enzymes Proteins 0.000 title claims abstract description 112
- 102000004190 Enzymes Human genes 0.000 title claims abstract description 112
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 112
- 239000002184 metal Substances 0.000 title claims abstract description 112
- 238000002386 leaching Methods 0.000 claims abstract description 137
- 238000000034 method Methods 0.000 claims abstract description 110
- 108090000623 proteins and genes Proteins 0.000 claims abstract description 11
- 238000002708 random mutagenesis Methods 0.000 claims abstract description 9
- 238000002741 site-directed mutagenesis Methods 0.000 claims abstract description 7
- 239000003795 chemical substances by application Substances 0.000 claims description 70
- 230000008569 process Effects 0.000 claims description 52
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 51
- 229910052802 copper Inorganic materials 0.000 claims description 51
- 239000010949 copper Substances 0.000 claims description 51
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 claims description 28
- OMZSGWSJDCOLKM-UHFFFAOYSA-N copper(II) sulfide Chemical compound [S-2].[Cu+2] OMZSGWSJDCOLKM-UHFFFAOYSA-N 0.000 claims description 24
- 108010086158 rusticyanin Proteins 0.000 claims description 17
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 15
- 239000011707 mineral Substances 0.000 claims description 15
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 14
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 13
- DVRDHUBQLOKMHZ-UHFFFAOYSA-N chalcopyrite Chemical compound [S-2].[S-2].[Fe+2].[Cu+2] DVRDHUBQLOKMHZ-UHFFFAOYSA-N 0.000 claims description 12
- 102000018832 Cytochromes Human genes 0.000 claims description 11
- 108010052832 Cytochromes Proteins 0.000 claims description 11
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 10
- 239000004332 silver Substances 0.000 claims description 10
- 229910052709 silver Inorganic materials 0.000 claims description 10
- 239000002253 acid Substances 0.000 claims description 9
- 239000002245 particle Substances 0.000 claims description 9
- 230000002378 acidificating effect Effects 0.000 claims description 8
- 229910052951 chalcopyrite Inorganic materials 0.000 claims description 8
- 230000001590 oxidative effect Effects 0.000 claims description 8
- 230000027756 respiratory electron transport chain Effects 0.000 claims description 8
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 7
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 7
- 239000000654 additive Substances 0.000 claims description 7
- 239000010941 cobalt Substances 0.000 claims description 7
- 229910017052 cobalt Inorganic materials 0.000 claims description 7
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 7
- 229910052955 covellite Inorganic materials 0.000 claims description 7
- 239000003599 detergent Substances 0.000 claims description 7
- 229910052759 nickel Inorganic materials 0.000 claims description 7
- 229920000642 polymer Polymers 0.000 claims description 7
- 238000007423 screening assay Methods 0.000 claims description 7
- 229910052725 zinc Inorganic materials 0.000 claims description 7
- 239000011701 zinc Substances 0.000 claims description 7
- 241000605222 Acidithiobacillus ferrooxidans Species 0.000 claims description 6
- 238000003556 assay Methods 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 6
- 239000007787 solid Substances 0.000 claims description 6
- 238000012360 testing method Methods 0.000 claims description 6
- 108010006519 Molecular Chaperones Proteins 0.000 claims description 5
- 230000000996 additive effect Effects 0.000 claims description 5
- 108010092351 cupredoxin Proteins 0.000 claims description 5
- 229910052742 iron Inorganic materials 0.000 claims description 5
- -1 silver ions Chemical class 0.000 claims description 5
- 102000005298 Iron-Sulfur Proteins Human genes 0.000 claims description 4
- 108010081409 Iron-Sulfur Proteins Proteins 0.000 claims description 4
- 239000011942 biocatalyst Substances 0.000 claims description 4
- 229910052948 bornite Inorganic materials 0.000 claims description 4
- 229910052947 chalcocite Inorganic materials 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 3
- 229910052737 gold Inorganic materials 0.000 claims description 3
- 239000010931 gold Substances 0.000 claims description 3
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 claims description 3
- DSRJIHMZAQEUJV-UHFFFAOYSA-N Cuprizon Chemical compound C1CCCCC1=NNC(=O)C(=O)NN=C1CCCCC1 DSRJIHMZAQEUJV-UHFFFAOYSA-N 0.000 claims description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 2
- FOIXSVOLVBLSDH-UHFFFAOYSA-N Silver ion Chemical compound [Ag+] FOIXSVOLVBLSDH-UHFFFAOYSA-N 0.000 claims description 2
- 229910052793 cadmium Inorganic materials 0.000 claims description 2
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 claims description 2
- YFHXZQPUBCBNIP-UHFFFAOYSA-N fura-2 Chemical compound CC1=CC=C(N(CC(O)=O)CC(O)=O)C(OCCOC=2C(=CC=3OC(=CC=3C=2)C=2OC(=CN=2)C(O)=O)N(CC(O)=O)CC(O)=O)=C1 YFHXZQPUBCBNIP-UHFFFAOYSA-N 0.000 claims description 2
- 229910052750 molybdenum Inorganic materials 0.000 claims description 2
- 239000011733 molybdenum Substances 0.000 claims description 2
- AHEWZZJEDQVLOP-UHFFFAOYSA-N monobromobimane Chemical compound BrCC1=C(C)C(=O)N2N1C(C)=C(C)C2=O AHEWZZJEDQVLOP-UHFFFAOYSA-N 0.000 claims description 2
- 230000001737 promoting effect Effects 0.000 claims description 2
- 150000003573 thiols Chemical class 0.000 claims description 2
- 230000001747 exhibiting effect Effects 0.000 claims 2
- 238000011065 in-situ storage Methods 0.000 claims 1
- 230000001699 photocatalysis Effects 0.000 claims 1
- 238000007146 photocatalysis Methods 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 16
- 150000002739 metals Chemical class 0.000 abstract description 14
- 244000005700 microbiome Species 0.000 abstract description 11
- 102000004169 proteins and genes Human genes 0.000 abstract description 9
- 235000010755 mineral Nutrition 0.000 description 12
- 238000006243 chemical reaction Methods 0.000 description 9
- 238000012545 processing Methods 0.000 description 9
- 238000005188 flotation Methods 0.000 description 8
- 241000894007 species Species 0.000 description 7
- 238000005363 electrowinning Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000011084 recovery Methods 0.000 description 5
- 241000894006 Bacteria Species 0.000 description 4
- 230000001580 bacterial effect Effects 0.000 description 4
- 239000003153 chemical reaction reagent Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000000975 dye Substances 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 238000012216 screening Methods 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 description 3
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- 239000012141 concentrate Substances 0.000 description 3
- 238000000227 grinding Methods 0.000 description 3
- 230000002209 hydrophobic effect Effects 0.000 description 3
- 238000005065 mining Methods 0.000 description 3
- 238000002703 mutagenesis Methods 0.000 description 3
- 231100000350 mutagenesis Toxicity 0.000 description 3
- 235000015097 nutrients Nutrition 0.000 description 3
- 108090000765 processed proteins & peptides Proteins 0.000 description 3
- 239000011435 rock Substances 0.000 description 3
- 238000000638 solvent extraction Methods 0.000 description 3
- 229910052569 sulfide mineral Inorganic materials 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 241000588724 Escherichia coli Species 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 150000001413 amino acids Chemical class 0.000 description 2
- 238000001311 chemical methods and process Methods 0.000 description 2
- 229910000365 copper sulfate Inorganic materials 0.000 description 2
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 2
- VFLDPWHFBUODDF-FCXRPNKRSA-N curcumin Chemical compound C1=C(O)C(OC)=CC(\C=C\C(=O)CC(=O)\C=C\C=2C=C(OC)C(O)=CC=2)=C1 VFLDPWHFBUODDF-FCXRPNKRSA-N 0.000 description 2
- DMBHHRLKUKUOEG-UHFFFAOYSA-N diphenylamine Chemical compound C=1C=CC=CC=1NC1=CC=CC=C1 DMBHHRLKUKUOEG-UHFFFAOYSA-N 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000011133 lead Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- 150000002923 oximes Chemical class 0.000 description 2
- 239000010665 pine oil Substances 0.000 description 2
- 102000004196 processed proteins & peptides Human genes 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000011343 solid material Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 239000012991 xanthate Substances 0.000 description 2
- RBTBFTRPCNLSDE-UHFFFAOYSA-N 3,7-bis(dimethylamino)phenothiazin-5-ium Chemical compound C1=CC(N(C)C)=CC2=[S+]C3=CC(N(C)C)=CC=C3N=C21 RBTBFTRPCNLSDE-UHFFFAOYSA-N 0.000 description 1
- 241001646130 Alkalimonas amylolytica Species 0.000 description 1
- 239000004382 Amylase Substances 0.000 description 1
- 102000013142 Amylases Human genes 0.000 description 1
- 108010065511 Amylases Proteins 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 241000196324 Embryophyta Species 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 241000233866 Fungi Species 0.000 description 1
- 108010025885 Glycerol dehydratase Proteins 0.000 description 1
- 241000588747 Klebsiella pneumoniae Species 0.000 description 1
- 235000019738 Limestone Nutrition 0.000 description 1
- 229920001410 Microfiber Polymers 0.000 description 1
- SJEYSFABYSGQBG-UHFFFAOYSA-M Patent blue Chemical compound [Na+].C1=CC(N(CC)CC)=CC=C1C(C=1C(=CC(=CC=1)S([O-])(=O)=O)S([O-])(=O)=O)=C1C=CC(=[N+](CC)CC)C=C1 SJEYSFABYSGQBG-UHFFFAOYSA-M 0.000 description 1
- 108091005804 Peptidases Proteins 0.000 description 1
- 239000004365 Protease Substances 0.000 description 1
- 108020004511 Recombinant DNA Proteins 0.000 description 1
- 102100037486 Reverse transcriptase/ribonuclease H Human genes 0.000 description 1
- MTCFGRXMJLQNBG-UHFFFAOYSA-N Serine Natural products OCC(N)C(O)=O MTCFGRXMJLQNBG-UHFFFAOYSA-N 0.000 description 1
- 108090000787 Subtilisin Proteins 0.000 description 1
- 108010056079 Subtilisins Proteins 0.000 description 1
- 102000005158 Subtilisins Human genes 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 241000499912 Trichoderma reesei Species 0.000 description 1
- 229910052770 Uranium Inorganic materials 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 235000019418 amylase Nutrition 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- UDSAIICHUKSCKT-UHFFFAOYSA-N bromophenol blue Chemical compound C1=C(Br)C(O)=C(Br)C=C1C1(C=2C=C(Br)C(O)=C(Br)C=2)C2=CC=CC=C2S(=O)(=O)O1 UDSAIICHUKSCKT-UHFFFAOYSA-N 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 108020001778 catalytic domains Proteins 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 229910001431 copper ion Inorganic materials 0.000 description 1
- BUGICWZUDIWQRQ-UHFFFAOYSA-N copper iron sulfane Chemical compound S.[Fe].[Cu] BUGICWZUDIWQRQ-UHFFFAOYSA-N 0.000 description 1
- BWFPGXWASODCHM-UHFFFAOYSA-N copper monosulfide Chemical class [Cu]=S BWFPGXWASODCHM-UHFFFAOYSA-N 0.000 description 1
- 239000004148 curcumin Substances 0.000 description 1
- 229940109262 curcumin Drugs 0.000 description 1
- 235000012754 curcumin Nutrition 0.000 description 1
- VFLDPWHFBUODDF-UHFFFAOYSA-N diferuloylmethane Natural products C1=C(O)C(OC)=CC(C=CC(=O)CC(=O)C=CC=2C=C(OC)C(O)=CC=2)=C1 VFLDPWHFBUODDF-UHFFFAOYSA-N 0.000 description 1
- 238000009510 drug design Methods 0.000 description 1
- 238000004070 electrodeposition Methods 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 229910052971 enargite Inorganic materials 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000009088 enzymatic function Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- ZZUFCTLCJUWOSV-UHFFFAOYSA-N furosemide Chemical compound C1=C(Cl)C(S(=O)(=O)N)=CC(C(O)=O)=C1NCC1=CC=CO1 ZZUFCTLCJUWOSV-UHFFFAOYSA-N 0.000 description 1
- 230000014509 gene expression Effects 0.000 description 1
- 235000003869 genetically modified organism Nutrition 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000009854 hydrometallurgy Methods 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
- 239000003446 ligand Substances 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 125000001360 methionine group Chemical group N[C@@H](CCSC)C(=O)* 0.000 description 1
- 229960000907 methylthioninium chloride Drugs 0.000 description 1
- 239000003658 microfiber Substances 0.000 description 1
- 230000035772 mutation Effects 0.000 description 1
- 239000002086 nanomaterial Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000002018 overexpression Effects 0.000 description 1
- 229910052592 oxide mineral Inorganic materials 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- FIKAKWIAUPDISJ-UHFFFAOYSA-L paraquat dichloride Chemical compound [Cl-].[Cl-].C1=C[N+](C)=CC=C1C1=CC=[N+](C)C=C1 FIKAKWIAUPDISJ-UHFFFAOYSA-L 0.000 description 1
- 230000006320 pegylation Effects 0.000 description 1
- 238000005325 percolation Methods 0.000 description 1
- YIBBMDDEXKBIAM-UHFFFAOYSA-M potassium;pentoxymethanedithioate Chemical compound [K+].CCCCCOC([S-])=S YIBBMDDEXKBIAM-UHFFFAOYSA-M 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 239000002265 redox agent Substances 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 229910052604 silicate mineral Inorganic materials 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 150000004763 sulfides Chemical group 0.000 description 1
- 230000002459 sustained effect Effects 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- DNYWZCXLKNTFFI-UHFFFAOYSA-N uranium Chemical compound [U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U] DNYWZCXLKNTFFI-UHFFFAOYSA-N 0.000 description 1
- 239000010878 waste rock Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B15/00—Obtaining copper
- C22B15/0063—Hydrometallurgy
- C22B15/0065—Leaching or slurrying
- C22B15/0067—Leaching or slurrying with acids or salts thereof
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B15/00—Other processes for the manufacture of iron from iron compounds
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/18—Extraction of metal compounds from ores or concentrates by wet processes with the aid of microorganisms or enzymes, e.g. bacteria or algae
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Definitions
- Copper sulfide ore processing is sustained by technologies based on physical and chemical processes associated with mineral crushing, grinding and flotation, followed by fusion-conversion of concentrates and electrolytic refining of metal.
- over 70% of copper is produced through the described route - known as the conventional route - which is limited to high and medium grade ores, according to the specific characteristics of deposits and of ore processing plants.
- ores in which copper is present in the form of oxide species are processed by means of acid leaching processes, followed by solvent extraction processes and electro- winning of the metal, in what is known as copper winning through hydrometallurgy.
- leaching of minerals may be accomplished in the presence of micro-organisms that enhance the leaching kinetics.
- the leaching environments are difficult for microorganisms due to the low pH, high ionic strength, and high temperatures.
- all hydro metallurgical processing conditions can be incredibly harsh to microorganisms.
- extremophiles i.e. , bacteria that thrive under extreme conditions
- bioleaching may be used in bioleaching.
- bioleaching is inherently inefficient because, for example, much of the organisms' energy must be expended by the organisms in life processes unrelated to mineral recovery, the organisms must be supplied with nutrients, many of which are incompatible with mineral processing and recovery, and leaching may tend to kill microorganisms or suppress their growth due to harsh environments (e.g. , low pH, high ionic strength, high temperatures, etc.).
- enzyme-based leaching agents that can be used to leach metals from metal-containing ores. Methods for recovering metals from metal- containing ores using such enzyme-based leaching agents are also described. Enzymes that are active under leaching conditions (e.g. , low pH, high ionic strength, high temperatures) may be isolated from microorganisms that are able to thrive under such conditions. In addition, the activity of enzymes that are identified as being active under leaching conditions may be improved through protein engineering techniques such as, but not limited to, random mutagenesis, site directed mutagenesis, directed evolution, combinatorial techniques, and the like.
- a leaching agent for recovering a metal from a metal- containing ore includes an acid and at least one enzyme associated with the acid and capable of promoting (e.g. , enhancing) leaching metal from the metal-containing ore.
- the leaching agent may be substantially abiotic.
- the at least one enzyme may include a native enzyme or a recombinant enzyme that is isolated from or derived from a microorganism.
- a method of recovering a metal from a metal- containing ore includes (1) contacting the ore with a leaching agent that includes at least one enzyme, wherein the leaching agent is substantially abiotic, (2) performing a leaching process with the leaching agent to leach the metal from the metal-containing ore, (3) producing at least one of a solid or liquid leachate from the leaching process, wherein the leachate includes the metal from the metal- containing ore, and (4) recovering the metal from the leachate.
- the method may include a method of recovering copper from a copper sulfide-containing ore.
- Such a method includes (1) contacting the copper sulfide-containing ore with an acidic, substantially abiotic leaching agent that includes Fe(III) and at least one enzyme capable of oxidizing Fe(II) to Fe(III), (2) performing a leaching process to leach the copper from the copper sulfide-containing ore, (3) producing at least one of a solid or liquid leachate from the leaching process, wherein the leachate includes the copper from the copper sulfide- containing ore, and (4) recovering copper metal from the leachate.
- the at least one enzyme may include at least one of rusticyanin or cytochrome C442.
- the copper sulfide-containing ore may include at least one of copper sulfide (chalcocite and covellite) or copper iron sulfide (chalcopyrite and bornite).
- copper sulfide chalcocite and covellite
- copper iron sulfide chalcopyrite and bornite
- Other metals that can be recovered using the methods described herein include, but are not limited to, molybdenum, gold, silver, and nickel.
- a screening assay may be performed to identify the at least one enzyme that is suitable for leaching the metal.
- crystalline nano-scale mineral particles may be pre-synthysized that represents, or otherwise approximate a composition of the metal-containing ore.
- the composition of the crystalline nano-scale mineral particles may be approximately about 0.001 ⁇ to about 0.1 ⁇ in diameter.
- the screening assay may further include subjecting the crystalline nano-scale mineral particles to a solution to form a plurality of homogenous test assays, and separately combining the test assays with different enzymes to identify the at least one enzyme.
- the different enzymes used may be previously subjected to random or site-specific mutagenesis.
- the screening assay further includes identifying colorometric, fluorometric, or calorimetric changes within any of the test assays.
- the solution may be include one or more of the following for identifying colorometric changes: a) ferrozine if the metal contains iron, copper, or cobalt; b) cuprizone if the metal contains copper; or c) PAR if the metal contains zinc, nickel, cobalt, or copper.
- the solution may include one or more of the following for identifying fluorometric changes: a) monobromobimane if the metal contains thiols; or b) Fura-2 if the metal contains manganese, cobalt, zinc, copper, nickel, or cadmium.
- colorometric changes may be identified with a photoelectric colorimeter or color standard comparison; fluorometric changes may be identified with a flurometer; and calorimetric changes may be identified using thermocouples or calorimeters.
- contacting the metal-containing ore with a leaching agent may include providing at least one non-biocatalyst.
- the at least one non-biocatalyst comprises light waves, microwaves, or radiowaves.
- Figure 1 illustrates a flow diagram for a biohydrometallurgy process according to an embodiment that may employ any of the leaching agents disclosed herein;
- Figure 2 illustrates a flow diagram for a biohydrometallurgy leaching process according to an embodiment that may employ any of the leaching agents disclosed herein;
- Figure 3 illustrates a flow diagram for a biohydrometallurgy process for recovering copper from a copper sulfide-containing ore according to an embodiment that may employ any of the leaching agents disclosed herein.
- enzyme-based leaching agents that can be used to leach metals from metal-containing ores. Methods for recovering metals from metal- containing ores using such enzyme-based leaching agents are also described. Enzymes that are active under leaching conditions (e.g. , low pH, high ionic strength, high temperatures) may be isolated from microorganisms that are able to thrive under such conditions. In addition, the activity of enzymes that are identified as being active under leaching conditions may be improved through protein engineering techniques such as, but not limited to, random mutagenesis, site directed mutagenesis, directed evolution, combinatorial techniques, and the like.
- a leaching agent for recovering a metal from a metal- containing ore includes at least one enzyme capable of leaching at least one metal or a metal-containing species from the metal-containing ore.
- the leaching agent is substantially abiotic.
- the term "abiotic” refers to a leaching agent that is substantially free of bacteria, fungi, and other living organisms that are capable of self-replication.
- the materials e.g. , metal containing ores
- the leaching agent itself is substantially abiotic.
- the leaching agent includes an acid to which a metal- containing ore may be exposed, such as by immersion in a leaching tank or percolation as occurs in heap leaching.
- the leaching agent may be a dry material that is added to the metal-containing ore.
- the leaching agent may include a lyophilized enzyme and any optional additives.
- Such a dry leaching agent may, for example, be activated by rehydrating the leaching agent in hydrated leach pile.
- the leaching agent may have an enzyme concentration sufficient to allow the concentration of enzyme in the leach agent to be about 1 ppm to about 1000 ppm or any concentration therebetween, such as about 5 ppm to about 100 ppm, or about 10 ppm to about 25 ppm.
- the enzyme may be added in a lyophilized state. The most concentrated is in mM range.
- the solution may be buffered to leach condition pH.
- detergents or fatty organics should not be added that are mobile in the leach pile.
- Detergents/ polymers may be used to get higher E solubilities for transport.
- PEGylation of the enzyme and immobilization of enzymes on a surface may be performed. This surface may be used to line leach vessels or be a media (such as beads) that is larger than the crushed ore and readily separated by screening after mixing with the ore slurry.
- the leaching agent may contain a redox agent to keep the enzyme in an active redox state prior to addition to the ore.
- the leaching agent further includes at least one of Fe(III) or a silver ion.
- Fe(III) may be used to convert insoluble copper sulfide species to soluble Cu 2+ ions.
- the reaction formula below illustrates this process:
- the enzyme(s) included in the leaching agent may be selected to be capable of converting Fe(II) to Fe(III). Such an enzyme can continually recycle Fe(II) to Fe(III) and keep the leaching reaction going forward.
- the leaching agent may include a native enzyme or a recombinant enzyme that is isolated from or derived from a microorganism.
- the enzyme is derived from an organism selected from the group consisting of acidophiles, thermophiles, halophiles, and combinations thereof.
- Acidithiobacillus ferrooxidans is a bacterium that is able to thrive in acidified sulfate soils, mine drainage effluents, and other mining areas.
- A. ferrooxidans naturally produces enzymes that can be used in enzyme-based leaching agents described herein.
- Such enzymes can be isolated as native enzymes from A. ferrooxidans or a similar organism or recombinant enzymes can be produced and isolated from other organisms (e.g., E. coli) using recombinant DNA technology.
- the enzyme includes at least one of a cupredoxin, a cytochrome, an iron- sulfur protein, or another enzyme that is capable of participating in one or more redox reactions involved in leaching metal(s) from metal-containing ores.
- the enzyme may be at least one of rusticyanin or cytochrome C442.
- rusticyanin is particularly preferred.
- Rusticyanin is a bacterial enzyme that is, in its native context, involved in electron- transfer. Rusticyanin is a copper- containing enzyme and a strong oxidant that can, for example, catalyze the conversion of Fe(II) to Fe(III). Overexpression and purification of the rusticyanin protein from A. ferrooxidans in E.
- the leaching agent may further include one or more of a chaperone, a detergent, a polymer additive (e.g., PEO, PVP, or combinations thereof), or an electron transfer dye in an amount of about 1-100 ppm.
- a chaperone e.g., PEO, PVP, or combinations thereof
- an electron transfer dye in an amount of about 1-100 ppm.
- Such additives may, for example, increase the stability and/or activity of the enzyme included in the leaching agent.
- the structure of the ore may prevent access by the enzyme to the metal-containing species or the ore may develop a crust in the leaching process that likewise prevents access by the enzyme to the metal-containing species.
- the electron transfer dye may be added to the leaching agent to shuttle electrons between the enzyme and the ore.
- Suitable examples of electron transfer dyes include, but are not limited to, methyl viologen (redox potential of about -660 mV (SHE)), patent blue, curcumin (redox potential of about 0.8-1 (SHE)), methylene blue (redox potential of 100-500 mV (SHE)), diphenylamine (redox potential of about 760 mV (SHE)), bromophenol blue, and the like.
- enzymes having identified activity under leaching conditions can be selectively engineered to increase their activity, increase pH stability, resistance to high ionic strength, high temperatures, and the like.
- Proteins may be re-engineered to alter their activity and/or their stability using a number of techniques. For instance, enzyme activity, stability, and the like may be improved through protein engineering techniques such as, but not limited to, random mutagenesis, site directed mutagenesis, directed evolution, combinatorial techniques, combinations thereof, and the like.
- rusticyanin the high-resolution three- dimensional structure of rusticyanin is known. This high-resolution three-dimensional structure can be used to identify candidate residues for mutagenesis in order to improve enzyme activity, stability, and the like.
- redox potentials may be tuned by altering the secondary sphere of an enzyme' s active site while pH stability may be increased by blocking solvent access to enzymes active site via steric interactions and hydrophobic amino acids. Altering the amino acid sequence of proteins can negatively impact the enzyme's activity (i.e. , how well it functions chemically). Nevertheless, high-throughput mutagenesis and analysis processes can be used to quickly identify successful mutants by producing a large number and screening them for activity under the harsh conditions of mineral processing. Those enzymes that remain active may then be sequenced and subjected to further study. In this way, a natural enzyme can be altered in order to yield an enzyme that is easily overexpressed and purified as well as being highly active and stable under leaching conditions.
- the activity and/or the stability of a natural enzyme may be altered so that the enzyme is active for recovering a metal from a metal-containing ore at under conditions such as, but not limited to, a pH in a range of 0-4 (e.g., 0-2, or 0-3), a high ionic strength up to and including a saturation point of one or more metals (e.g. , copper ions) from the metal-containing ore, or a temperature up to about 80 °C.
- these altered proteins are not subject to any special environmental regulations and, because they cannot self-replicate, they are therefore seen as catalysts opposed to biological reagents.
- the biohydrometallurgy process 100 includes a step 110 of mining and/or receiving the metal-containing ore.
- Most copper ores contain only a small percentage of copper metal, with the remainder of the ore being unwanted rock or waste minerals, typically silicate minerals or oxide minerals for which there is often no value.
- the average grade of copper ores in the 21st century is below 1% copper, with a proportion of economic ore minerals (including copper) being less than 2% of the total volume of the ore rock.
- a key objective in the metallurgical treatment of any ore is the separation of ore minerals from the waste materials within the rock.
- Comminution 120 is a process in which solid materials are reduced in size, by crushing, grinding and other processes.
- the most common machines for the comminution of coarse feed material are the jaw crusher (lm > P80 > 100 mm), cone crusher (P80 > 20 mm) and hammer crusher.
- Primary jaw crusher product in intermediate feed particle size ranges (100mm > P80 > 20mm) can be ground in autogenous or semi-autogenous mills depending on feed properties and application requirements.
- the metal-containing ore may be subjected to flotation 130 prior to leaching 140.
- Flotation 130 is essentially a concentration process. Flotation 130 is particularly effective for concentrating copper obtained from copper- containing ores. Remember that it is likely that less than 1% (e.g. , about 0.6%) of the ore is copper. In such cases, it may be desirable to concentrate the proportion of copper in the ore prior to further processing.
- the ore from the comminution process 120 may be combined with water to form a slurry and the slurry is mixed with milk of lime (simply water and ground-up limestone) to give a basic pH, an oil (e.g. , pine oil) to make bubbles, an alcohol to strengthen the bubbles, and a flotation reagent - e.g. , potassium amyl xanthate or a peptide flotation reagent.
- lime e.g. , water and ground-up limestone
- an oil e.g. , pine oil
- a flotation reagent e.g. , potassium amyl xanthate or a peptide flotation reagent.
- the xanthates or the peptides are added to the slurry in relatively small quantities.
- the xanthates or peptides are long chain molecules. In one embodiment, one end of the chain is polar and sticks to sulfide minerals while the other end is nonpolar and is attracted to the nonpolar hydrocarbon pine oil molecules.
- Raising the pH causes the polar end to ionize more and to preferentially stick to sulfide minerals (e.g. , chalcopyrite (CuFeS 2 ) or chalcocite (Cu 2 S)).
- sulfide minerals e.g. , chalcopyrite (CuFeS 2 ) or chalcocite (Cu 2 S)
- Air is blown into the tanks and agitated like a giant blender, producing a foamy froth.
- the sulfide mineral grains become coated with the flotation reagent with their hydrophobic ends waving around trying urgent to get out of the water.
- the hydrophobic tails attach themselves to the oily air bubbles which become coated with chalcopyrite grains as they rise to the surface and flow over the edge of the tank. In this manner through a series of steps the ore is concentrated. For example, copper ore can be concentrated from about 0.6% to an eventual value of about 30% copper. Waste rock particles do not adhere to the bubbles and drop to the bottom of the tank.
- the ground and/or concentrated ore may be subjected to a leaching process 140 to liberate the metal form the metal- containing ore.
- Leaching is an extraction process used to extract precious metals, copper, uranium, and other metals from ore via a series of chemical reactions that absorbs specific minerals and then re-separate them after their division from other earth materials.
- the leaching 140 may be a heap leaching process. In heap leaching, the ore is piled on a lined bed and then leaching chemicals are percolated through the pile to leach metal from the ore.
- the enzyme- based leaching processes described herein may be preferable to known bioleaching processes that use bacterial consortia because the heap leaching process can generate a great deal of heat that can kill living cells; however, enzymes may be unaffected.
- enzymes do not require nutrients or battle with existing heap components and become altered in the activity. For example, bacteria compete for nutrients and eventually die off.
- the leaching 140 may include a tank leaching process where the ore and the leaching chemical are combined in a tank and stirred to promote separation of metal from the ore.
- the enzyme-based methods described herein may be further preferable to known bioleaching processes that use bacterial consortia in that the mixing processes may actually tend to physically rupture cells by grinding them or smashing them between the ore material.
- the leaching process 140 includes a step 210 of contacting the ore with a substantially abiotic leaching agent that includes at least one enzyme.
- the at least one enzyme has a concentration in the leaching agent of a lower concentration of about 1 ppm, 5 ppm, 10 ppm, 15 ppm, 20 ppm, 30 ppm, 50 ppm, 75 ppm, 100 ppm, 150 ppm, 200 ppm, 300 ppm, 400 ppm, or about 500 ppm; an upper concentration of about 1000 ppm, 900 ppm, 800 ppm, 700 ppm, 600 ppm, 550 ppm, 500 ppm, 450 ppm or about 400 ppm, and any combination of the recited lower and upper concentration values, such as about 1 ppm to about 1000 ppm (e.g., 5-10 ppm, 1-5 ppm, or
- the leaching 140 further includes a step 220 of performing a leaching process to leach the metal from the metal-containing ore.
- the at least one enzyme in the leaching agent is capable of participating in one or more chemical reactions that separate the metal from the metal containing ore.
- the enzyme may be an iron oxidizing enzyme.
- rusticyanin is oxidizing enough to oxidize chalcopyrite.
- the leaching process may include converting Fe(III) to Fe(II) to yield a soluble metal species from the metal-containing ore and the leaching process may then further include enzymatically converting the Fe(II) produced in the leaching process back to Fe(III).
- the enzyme may be at least one of a cupredoxin, a cytochrome, or an iron-sulfur protein. Suitable examples of enzymes include, but are not limited to rusticyanin or cytochrome C442.
- the leaching 140 further includes a step 230 of producing at least one of a solid or liquid leachate from the leaching process, wherein the leachate includes the metal from the metal-containing ore.
- the metal(s) may be recovered from the leachate in steps 150- 170.
- the leachate is treated to remove impurities from the leachate.
- impurities may be removed with the use of ion exchange resins, molecular recognition, microfibers (e.g., carbon nanomaterial), or by biorecognition.
- the metal is extracted from the leachate by solvent extraction.
- copper is typically extracted acidic leachate by adding phenolic oxime compounds to the leachate that selectively complex with copper.
- the copper complexed with oxime can be recovered from the leachate.
- the oxime is recycled and the copper is sent to further processing.
- step 170 the metal(s) from the solvent extraction step 160 are purified by electrowinning.
- Electro winning also called electroextraction, is an electrodeposition process where metals in solution are electrodeposited on an electrode surface. Electrowinning uses electroplating on a large scale - the resulting metals are said to be electrowon. The metal is deposited on the cathode (either in solid or in liquid form), while the anodic reaction is usually oxygen evolution.
- the most common electrowon metals are lead, copper, gold, silver, zinc, aluminium, chromium, cobalt, manganese, and the rare-earth and alkali metals. For aluminium, this is the only production process employed.
- a specific embodiment of a method 300 for extracting copper from a copper sulfide-containing ore includes a step 310 of providing a copper sulfide-containing ore.
- the copper sulfide-containing ore may include the copper sulfide- containing ore includes at least one of copper sulfide (chalcocite and covellite) or copper iron sulfide (chalcopyrite and bornite).
- Method 300 further includes a step 320 of contacting the copper sulfide- containing ore with an acidic, substantially abiotic leaching agent that includes Fe(III) and at least one enzyme capable of oxidizing Fe(II) to Fe(III).
- the enzyme may be at least one of rusticyanin or cytochrome C442.
- a suitable example of such an enzyme is rusticyanin.
- the enzyme has a concentration in the leaching process of about 1 ppm to about 1000 ppm.
- the leaching solution further comprising one or more of a chaperone, a detergent, a polymer additive, or an electron transfer dye.
- the leaching agent may include silver ions in addition to Fe(III). Silver ions are capable of participating in chemical reactions to liberate copper from copper sulfate ore similarly to iron.
- silver is highly toxic to most living organisms, the enzyme based processes described herein can use silver, whereas processes that uses bacterial consortia cannot use silver because the silver could kill some or all of the organisms in the consortia.
- the method 300 further includes a step 330 of performing a leaching process wherein the enzyme is allowed to participate in one or more chemical reactions to recover copper from the copper sulfate ore.
- the leaching process 330 produces a leachate in step 340 that includes copper recovered from the ore.
- the method 300 finally includes a step 350 of recovering copper metal from the leachate.
- the metal may, for example, be recovered from the leachate according to steps 150-170 described in reference to Figure 1.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biochemistry (AREA)
- Biotechnology (AREA)
- Microbiology (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
Enzyme-based leaching agents for leaching metals from metal-containing ores. Methods for recovering metals from a metal-containing ores using such enzyme-based leaching agents are also described. Enzymes that are active under leaching conditions (e.g., low pH, high ionic strength, high temperatures) may be isolated from microorganisms. In addition, the activity of enzymes that are identified as being active under leaching conditions may be improved through protein engineering techniques such as, but not limited to, random mutagenesis, site directed mutagenesis, directed evolution, combinatorial techniques, and the like.
Description
USE OF ENZYMES FOR RECOVERING A METAL FROM A METAL- CONTAINING ORE
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is an international PCT application which claims priority to United States Provisional Patent Application Serial No. 61/746,710 filed on 28 December 2012.
BACKGROUND
[0002] Many of the world's metal containing ores contain only small amounts (e.g. , by percent weight) of desirable metals. In order to make such ores commercially viable, it is often necessary to leach (i.e. , extract) the metal from the ore and concentrate it prior to further processing.
[0003] For example, over 90% the world's mine copper is currently obtained from copper sulfide ore processing. The most important copper sulfide species present in ores are chalcopyrite, bornite chalcosite, covellite, tenantite and enargite, of which chalcopyrite is the species found in most relative abundance and, therefore, the one of greatest economic interest. High-grade copper ores may only contain about 2% copper by weight and low-grade ores, which may be commercially viable nonetheless, may contain less than 1% copper by weight.
[0004] Copper sulfide ore processing is sustained by technologies based on physical and chemical processes associated with mineral crushing, grinding and flotation, followed by fusion-conversion of concentrates and electrolytic refining of metal. In practice, over 70% of copper is produced through the described route - known as the conventional route - which is limited to high and medium grade ores, according to the specific characteristics of deposits and of ore processing plants.
[0005] On the other hand, ores in which copper is present in the form of oxide species (easily soluble in acid) are processed by means of acid leaching processes, followed by solvent extraction processes and electro- winning of the metal, in what is known as copper winning through hydrometallurgy. This route is very attractive due to its lower operation and investment costs when compared to conventional technologies, as well as to its lower environmental impact. Nevertheless, applications of this technology are limited to oxide ores, or to copper sulfide mixed ores in which metal is present in the form of secondary sulfides (chalcosite and covellite) that are acid soluble in the presence of an energetic oxidizing agent catalyzed by microorganisms.
[0006] As an alternative to the processes described above, leaching of minerals may be accomplished in the presence of micro-organisms that enhance the leaching kinetics. However, the leaching environments are difficult for microorganisms due to the low pH, high ionic strength, and high temperatures. In fact, all hydro metallurgical processing conditions can be incredibly harsh to microorganisms. In some instances, extremophiles (i.e. , bacteria that thrive under extreme conditions) may be used in bioleaching. Nevertheless, bioleaching is inherently inefficient because, for example, much of the organisms' energy must be expended by the organisms in life processes unrelated to mineral recovery, the organisms must be supplied with nutrients, many of which are incompatible with mineral processing and recovery, and leaching may tend to kill microorganisms or suppress their growth due to harsh environments (e.g. , low pH, high ionic strength, high temperatures, etc.).
SUMMARY
[0007] Described herein are enzyme-based leaching agents that can be used to leach metals from metal-containing ores. Methods for recovering metals from metal- containing ores using such enzyme-based leaching agents are also described. Enzymes that are active under leaching conditions (e.g. , low pH, high ionic strength, high temperatures) may be isolated from microorganisms that are able to thrive under such conditions. In addition, the activity of enzymes that are identified as being active under leaching conditions may be improved through protein engineering techniques such as, but not limited to, random mutagenesis, site directed mutagenesis, directed evolution, combinatorial techniques, and the like.
[0008] In an embodiment, a leaching agent for recovering a metal from a metal- containing ore is described. The leaching agent includes an acid and at least one enzyme associated with the acid and capable of promoting (e.g. , enhancing) leaching metal from the metal-containing ore. For example, the leaching agent may be substantially abiotic. In one embodiment, the at least one enzyme may include a native enzyme or a recombinant enzyme that is isolated from or derived from a microorganism.
[0009] In another embodiment, a method of recovering a metal from a metal- containing ore is described. The method includes (1) contacting the ore with a leaching agent that includes at least one enzyme, wherein the leaching agent is substantially abiotic, (2) performing a leaching process with the leaching agent to leach the metal from the metal-containing ore, (3) producing at least one of a solid or liquid leachate from the leaching process, wherein the leachate includes the metal from the metal- containing ore, and (4) recovering the metal from the leachate.
[0010] In a more specific embodiment, the method may include a method of recovering copper from a copper sulfide-containing ore. Such a method includes (1) contacting the copper sulfide-containing ore with an acidic, substantially abiotic leaching agent that includes Fe(III) and at least one enzyme capable of oxidizing Fe(II) to Fe(III), (2) performing a leaching process to leach the copper from the copper sulfide-containing ore, (3) producing at least one of a solid or liquid leachate from the leaching process, wherein the leachate includes the copper from the copper sulfide- containing ore, and (4) recovering copper metal from the leachate.
[0011] In one embodiment, the at least one enzyme may include at least one of rusticyanin or cytochrome C442. In one embodiment, the copper sulfide-containing ore may include at least one of copper sulfide (chalcocite and covellite) or copper iron sulfide (chalcopyrite and bornite). Other metals that can be recovered using the methods described herein include, but are not limited to, molybdenum, gold, silver, and nickel.
[0012] In an embodiment, a screening assay may be performed to identify the at least one enzyme that is suitable for leaching the metal. In an embodiment, crystalline nano-scale mineral particles may be pre-synthysized that represents, or otherwise approximate a composition of the metal-containing ore. In an embodiment, the composition of the crystalline nano-scale mineral particles may be approximately about 0.001 μιη to about 0.1 μιη in diameter. In some embodiments, the screening assay may further include subjecting the crystalline nano-scale mineral particles to a solution to form a plurality of homogenous test assays, and separately combining the test assays with different enzymes to identify the at least one enzyme. In some embodiments, the
different enzymes used may be previously subjected to random or site-specific mutagenesis.
[0013] In an embodiment, the screening assay further includes identifying colorometric, fluorometric, or calorimetric changes within any of the test assays. For example, the solution may be include one or more of the following for identifying colorometric changes: a) ferrozine if the metal contains iron, copper, or cobalt; b) cuprizone if the metal contains copper; or c) PAR if the metal contains zinc, nickel, cobalt, or copper. In an embodiment, the solution may include one or more of the following for identifying fluorometric changes: a) monobromobimane if the metal contains thiols; or b) Fura-2 if the metal contains manganese, cobalt, zinc, copper, nickel, or cadmium. For example, colorometric changes may be identified with a photoelectric colorimeter or color standard comparison; fluorometric changes may be identified with a flurometer; and calorimetric changes may be identified using thermocouples or calorimeters.
[0014] In a further embodiment, contacting the metal-containing ore with a leaching agent may include providing at least one non-biocatalyst. For example, the at least one non-biocatalyst comprises light waves, microwaves, or radiowaves.
[0015] Features from any of the disclosed embodiments may be used in combination with one another, without limitation. In addition, other features and advantages of the present disclosure will become apparent to those of ordinary skill in the art through consideration of the following detailed description and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] To further clarify the above and other advantages and features of embodiments of the present invention, a more particular description will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is appreciated that these drawings depict only illustrated embodiments of the invention and are therefore not to be considered limiting of its scope. Various embodiments of the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
[0017] Figure 1 illustrates a flow diagram for a biohydrometallurgy process according to an embodiment that may employ any of the leaching agents disclosed herein;
[0018] Figure 2 illustrates a flow diagram for a biohydrometallurgy leaching process according to an embodiment that may employ any of the leaching agents disclosed herein; and
[0019] Figure 3 illustrates a flow diagram for a biohydrometallurgy process for recovering copper from a copper sulfide-containing ore according to an embodiment that may employ any of the leaching agents disclosed herein.
DETAILED DESCRIPTION
[0020] Described herein are enzyme-based leaching agents that can be used to leach metals from metal-containing ores. Methods for recovering metals from metal- containing ores using such enzyme-based leaching agents are also described. Enzymes that are active under leaching conditions (e.g. , low pH, high ionic strength, high temperatures) may be isolated from microorganisms that are able to thrive under such conditions. In addition, the activity of enzymes that are identified as being active under leaching conditions may be improved through protein engineering techniques such as, but not limited to, random mutagenesis, site directed mutagenesis, directed evolution, combinatorial techniques, and the like.
I. LEACHING AGENTS
[0021] In an embodiment, a leaching agent for recovering a metal from a metal- containing ore is described. The leaching agent includes at least one enzyme capable of leaching at least one metal or a metal-containing species from the metal-containing ore. Preferably, the leaching agent is substantially abiotic. As used herein, the term "abiotic" refers to a leaching agent that is substantially free of bacteria, fungi, and other living organisms that are capable of self-replication. One will appreciate that while the materials (e.g. , metal containing ores) that the leaching agent is applied to may include microorganisms that can proliferate under leaching conditions, the leaching agent itself is substantially abiotic.
[0022] In one embodiment, the leaching agent includes an acid to which a metal- containing ore may be exposed, such as by immersion in a leaching tank or percolation as occurs in heap leaching. In another embodiment, the leaching agent may be a dry material that is added to the metal-containing ore. For instance, the leaching agent may
include a lyophilized enzyme and any optional additives. Such a dry leaching agent may, for example, be activated by rehydrating the leaching agent in hydrated leach pile. The leaching agent may have an enzyme concentration sufficient to allow the concentration of enzyme in the leach agent to be about 1 ppm to about 1000 ppm or any concentration therebetween, such as about 5 ppm to about 100 ppm, or about 10 ppm to about 25 ppm.
[0023] In an embodiment, the enzyme may be added in a lyophilized state. The most concentrated is in mM range. The solution may be buffered to leach condition pH. In some embodiments, detergents or fatty organics should not be added that are mobile in the leach pile. Detergents/ polymers may be used to get higher E solubilities for transport. In an embodiment, PEGylation of the enzyme and immobilization of enzymes on a surface may be performed. This surface may be used to line leach vessels or be a media (such as beads) that is larger than the crushed ore and readily separated by screening after mixing with the ore slurry. The leaching agent may contain a redox agent to keep the enzyme in an active redox state prior to addition to the ore.
[0024] In one embodiment, the leaching agent further includes at least one of Fe(III) or a silver ion. For instance, in the recovery of copper from copper sulfide ores, Fe(III) may be used to convert insoluble copper sulfide species to soluble Cu2+ ions. For example, the reaction formula below illustrates this process:
CuS + 8 Fe3+ + 4 H20→ Cu2+ + 8 Fe2+ + S04 2~ + 8 H+ Formula 1
Recovery of copper from copper-iron-sulfide ores (e.g. , chalcopyrite) can be accomplished by a similar chemical process. Likewise, similar chemistry can be used for recovery of metals such as lead, nickel, and zinc from sulfide-containing ores. However, in order to maintain the process, it is necessary to either begin the process
with an excess of Fe(III), replenish the Fe(III) by continuing to add more as the leaching progresses, or convert the Fe(II) back to Fe(III).
[0025] Starting with an excess of Fe(III) and/or continually adding Fe(III) to the leach are expensive and impractical. This can be appreciated by reviewing Formula 1 above: 8 moles of Fe(III) is needed in order to recover 1 mole of Cu2+ from CuS. Other copper sulfides require even more Fe(III). However, in one embodiment, the enzyme(s) included in the leaching agent may be selected to be capable of converting Fe(II) to Fe(III). Such an enzyme can continually recycle Fe(II) to Fe(III) and keep the leaching reaction going forward.
[0026] In one embodiment, the leaching agent may include a native enzyme or a recombinant enzyme that is isolated from or derived from a microorganism. In one embodiment, the enzyme is derived from an organism selected from the group consisting of acidophiles, thermophiles, halophiles, and combinations thereof. For example, Acidithiobacillus ferrooxidans is a bacterium that is able to thrive in acidified sulfate soils, mine drainage effluents, and other mining areas. A. ferrooxidans naturally produces enzymes that can be used in enzyme-based leaching agents described herein. Such enzymes can be isolated as native enzymes from A. ferrooxidans or a similar organism or recombinant enzymes can be produced and isolated from other organisms (e.g., E. coli) using recombinant DNA technology.
[0027] In one embodiment, the enzyme includes at least one of a cupredoxin, a cytochrome, an iron- sulfur protein, or another enzyme that is capable of participating in one or more redox reactions involved in leaching metal(s) from metal-containing ores. For example, the enzyme may be at least one of rusticyanin or cytochrome C442. In one embodiment, rusticyanin is particularly preferred. Rusticyanin is a bacterial enzyme
that is, in its native context, involved in electron- transfer. Rusticyanin is a copper- containing enzyme and a strong oxidant that can, for example, catalyze the conversion of Fe(II) to Fe(III). Overexpression and purification of the rusticyanin protein from A. ferrooxidans in E. coli is described in "Gene Synthesis, High-Level Expression, and Mutagenesis of Thiobacillus ferrooxidans Rusticyanin: His 85 Is a Ligand to the Blue Copper Center," Casimiro et al., Biochemistry 1995, 34, 6640-6648, the entirety of which is incorporated herein by reference.
[0028] In one embodiment, the leaching agent may further include one or more of a chaperone, a detergent, a polymer additive (e.g., PEO, PVP, or combinations thereof), or an electron transfer dye in an amount of about 1-100 ppm. Such additives may, for example, increase the stability and/or activity of the enzyme included in the leaching agent. For example, the structure of the ore may prevent access by the enzyme to the metal-containing species or the ore may develop a crust in the leaching process that likewise prevents access by the enzyme to the metal-containing species. In such a case, the electron transfer dye may be added to the leaching agent to shuttle electrons between the enzyme and the ore. Suitable examples of electron transfer dyes include, but are not limited to, methyl viologen (redox potential of about -660 mV (SHE)), patent blue, curcumin (redox potential of about 0.8-1 (SHE)), methylene blue (redox potential of 100-500 mV (SHE)), diphenylamine (redox potential of about 760 mV (SHE)), bromophenol blue, and the like.
[0029] In addition to the foregoing, enzymes having identified activity under leaching conditions can be selectively engineered to increase their activity, increase pH stability, resistance to high ionic strength, high temperatures, and the like. Proteins may be re-engineered to alter their activity and/or their stability using a number of
techniques. For instance, enzyme activity, stability, and the like may be improved through protein engineering techniques such as, but not limited to, random mutagenesis, site directed mutagenesis, directed evolution, combinatorial techniques, combinations thereof, and the like. Referring specifically to rusticyanin, the high-resolution three- dimensional structure of rusticyanin is known. This high-resolution three-dimensional structure can be used to identify candidate residues for mutagenesis in order to improve enzyme activity, stability, and the like.
[0030] For example, redox potentials may be tuned by altering the secondary sphere of an enzyme' s active site while pH stability may be increased by blocking solvent access to enzymes active site via steric interactions and hydrophobic amino acids. Altering the amino acid sequence of proteins can negatively impact the enzyme's activity (i.e. , how well it functions chemically). Nevertheless, high-throughput mutagenesis and analysis processes can be used to quickly identify successful mutants by producing a large number and screening them for activity under the harsh conditions of mineral processing. Those enzymes that remain active may then be sequenced and subjected to further study. In this way, a natural enzyme can be altered in order to yield an enzyme that is easily overexpressed and purified as well as being highly active and stable under leaching conditions.
[0031] For instance, the activity and/or the stability of a natural enzyme may be altered so that the enzyme is active for recovering a metal from a metal-containing ore at under conditions such as, but not limited to, a pH in a range of 0-4 (e.g., 0-2, or 0-3), a high ionic strength up to and including a saturation point of one or more metals (e.g. , copper ions) from the metal-containing ore, or a temperature up to about 80 °C. In contrast to natural and genetically modified organisms that may be used in bioleaching,
these altered proteins are not subject to any special environmental regulations and, because they cannot self-replicate, they are therefore seen as catalysts opposed to biological reagents.
[0032] Further discussion of such techniques and examples of their use for altering the activity of proteins can be found in "Enhancement of pH stability and activity of glycerol dehydratase from Klebsiella pneumoniae by rational design," Qi X et al., Biotechnol Lett. 2012 Feb;34(2):339-46; "Improvement in the alkaline stability of subtilisin using an efficient random mutagenesis and screening procedure," Cunningham et al., Protein Eng. (1987) 1 (4): 319-325; "Structure-based replacement of methionine residues at the catalytic domains with serine significantly improves the oxidative stability of alkaline amylase from alkaliphilic Alkalimonas amylolytica," Yang et al., Biotechnology Progress, Volume 28, Issue 5, pages 1271-1277, September/October 2012; "Modulating the Redox Potential and Acid Stability of Rusticyanin by Site-Directed Mutagenesis of Ser86," Hall et al., Biochemistry, 1998, 37 (33), pp 11451-11458; "Rationally tuning the reduction potential of a single cupredoxin beyond the natural range," Marshall et al., Nature 462, 113-116 (5 November 2009); "A combination of weakly stabilizing mutations with a disulfide bridge in the a-helix region of Trichoderma reesei endo-l,4-P-xylanase II increases the thermal stability through synergism," Turunena et al., Journal of Biotechnology, Volume 88, Issue 1, 1 June 2001, Pages 37-46; "Engineering of a Cold- Adapted Protease by Sequential Random Mutagenesis and a Screening System," Taguchi et al., Appl. Environ. Microbiol. February 1998 vol. 64 no. 2 492-495; "Tuning the activity of an enzyme for unusual environments: sequential random mutagenesis of subtilisin E for catalysis in dimethylformamide," Chen et al., PNAS June 15, 1993 vol. 90 no. 12 5618-
5622; and "Optimising enzyme function by directed evolution," Dalby et al., Current Opinion in Structural Biology, Volume 13, Issue 4, August 2003, Pages 500-505, the entireties of which are incorporated herein by reference.
II. METHODS OF RECOVERING A METAL FROM A METAL- CONTAINING ORE
[0033] Referring now to Figure 1, a flow diagram for a biohydrometallurgy process 100 is illustrated according to an embodiment, which may employ any of the leaching agents disclosed herein. The biohydrometallurgy process 100 includes a step 110 of mining and/or receiving the metal-containing ore. Most copper ores contain only a small percentage of copper metal, with the remainder of the ore being unwanted rock or waste minerals, typically silicate minerals or oxide minerals for which there is often no value. The average grade of copper ores in the 21st century is below 1% copper, with a proportion of economic ore minerals (including copper) being less than 2% of the total volume of the ore rock. A key objective in the metallurgical treatment of any ore is the separation of ore minerals from the waste materials within the rock.
[0034] Following mining of the ore 110, the ore is subjected to a process called comminution 120. Comminution is a process in which solid materials are reduced in size, by crushing, grinding and other processes. There are several methods of comminution. Comminution of solid materials requires different types of crushers and mills depending on the feed properties such as hardness at various size ranges and application requirements such as throughput and maintenance. The most common machines for the comminution of coarse feed material are the jaw crusher (lm > P80 > 100 mm), cone crusher (P80 > 20 mm) and hammer crusher. Primary jaw crusher
product in intermediate feed particle size ranges (100mm > P80 > 20mm) can be ground in autogenous or semi-autogenous mills depending on feed properties and application requirements. For comminution of finer particle size ranges (20mm > P80 > 30 μιη) machines like the ball mill, vertical roller mill, hammer mill, roller press or high compression roller mill, vibration mill, jet mill and others may be used.
[0035] Following comminution 120, the metal-containing ore may be subjected to flotation 130 prior to leaching 140. Flotation 130 is essentially a concentration process. Flotation 130 is particularly effective for concentrating copper obtained from copper- containing ores. Remember that it is likely that less than 1% (e.g. , about 0.6%) of the ore is copper. In such cases, it may be desirable to concentrate the proportion of copper in the ore prior to further processing.
[0036] In such a case, the ore from the comminution process 120 may be combined with water to form a slurry and the slurry is mixed with milk of lime (simply water and ground-up limestone) to give a basic pH, an oil (e.g. , pine oil) to make bubbles, an alcohol to strengthen the bubbles, and a flotation reagent - e.g. , potassium amyl xanthate or a peptide flotation reagent.
[0037] The xanthates or the peptides are added to the slurry in relatively small quantities. The xanthates or peptides are long chain molecules. In one embodiment, one end of the chain is polar and sticks to sulfide minerals while the other end is nonpolar and is attracted to the nonpolar hydrocarbon pine oil molecules.
[0038] Raising the pH causes the polar end to ionize more and to preferentially stick to sulfide minerals (e.g. , chalcopyrite (CuFeS2) or chalcocite (Cu2S)). Air is blown into the tanks and agitated like a giant blender, producing a foamy froth. The sulfide mineral
grains become coated with the flotation reagent with their hydrophobic ends waving around trying desperately to get out of the water.
[0039] The hydrophobic tails attach themselves to the oily air bubbles which become coated with chalcopyrite grains as they rise to the surface and flow over the edge of the tank. In this manner through a series of steps the ore is concentrated. For example, copper ore can be concentrated from about 0.6% to an eventual value of about 30% copper. Waste rock particles do not adhere to the bubbles and drop to the bottom of the tank.
Following either comminution 120 or flotation 130, the ground and/or concentrated ore may be subjected to a leaching process 140 to liberate the metal form the metal- containing ore. Leaching is an extraction process used to extract precious metals, copper, uranium, and other metals from ore via a series of chemical reactions that absorbs specific minerals and then re-separate them after their division from other earth materials. In one embodiment, the leaching 140 may be a heap leaching process. In heap leaching, the ore is piled on a lined bed and then leaching chemicals are percolated through the pile to leach metal from the ore. In the case of heap leaching, the enzyme- based leaching processes described herein may be preferable to known bioleaching processes that use bacterial consortia because the heap leaching process can generate a great deal of heat that can kill living cells; however, enzymes may be unaffected.
Furthermore, enzymes do not require nutrients or battle with existing heap components and become altered in the activity. For example, bacteria compete for nutrients and eventually die off.
[0040] In another embodiment, the leaching 140 may include a tank leaching process where the ore and the leaching chemical are combined in a tank and stirred to
promote separation of metal from the ore. In the case of stirred reactor or agitated leach vessel, the enzyme-based methods described herein may be further preferable to known bioleaching processes that use bacterial consortia in that the mixing processes may actually tend to physically rupture cells by grinding them or smashing them between the ore material.
[0041] Referring now to Figure 2, the leaching process 140 is illustrated in greater detail according to an embodiment. The leaching process includes a step 210 of contacting the ore with a substantially abiotic leaching agent that includes at least one enzyme. In one embodiment, the at least one enzyme has a concentration in the leaching agent of a lower concentration of about 1 ppm, 5 ppm, 10 ppm, 15 ppm, 20 ppm, 30 ppm, 50 ppm, 75 ppm, 100 ppm, 150 ppm, 200 ppm, 300 ppm, 400 ppm, or about 500 ppm; an upper concentration of about 1000 ppm, 900 ppm, 800 ppm, 700 ppm, 600 ppm, 550 ppm, 500 ppm, 450 ppm or about 400 ppm, and any combination of the recited lower and upper concentration values, such as about 1 ppm to about 1000 ppm (e.g., 5-10 ppm, 1-5 ppm, or 5-15 ppm).
[0042] The leaching 140 further includes a step 220 of performing a leaching process to leach the metal from the metal-containing ore. As explained in greater detail herein above, the at least one enzyme in the leaching agent is capable of participating in one or more chemical reactions that separate the metal from the metal containing ore. In one embodiment, the enzyme may be an iron oxidizing enzyme. For example, rusticyanin is oxidizing enough to oxidize chalcopyrite.
[0043] For example, the leaching process may include converting Fe(III) to Fe(II) to yield a soluble metal species from the metal-containing ore and the leaching process may then further include enzymatically converting the Fe(II) produced in the leaching
process back to Fe(III). In one embodiment, the enzyme may be at least one of a cupredoxin, a cytochrome, or an iron-sulfur protein. Suitable examples of enzymes include, but are not limited to rusticyanin or cytochrome C442.
[0044] The leaching 140 further includes a step 230 of producing at least one of a solid or liquid leachate from the leaching process, wherein the leachate includes the metal from the metal-containing ore.
[0045] Referring again to Figure 1, following the leaching process 140, the metal(s) may be recovered from the leachate in steps 150- 170. In step 150, the leachate is treated to remove impurities from the leachate. For example, impurities may be removed with the use of ion exchange resins, molecular recognition, microfibers (e.g., carbon nanomaterial), or by biorecognition.
[0046] In step 160, the metal is extracted from the leachate by solvent extraction. For example, copper is typically extracted acidic leachate by adding phenolic oxime compounds to the leachate that selectively complex with copper. The copper complexed with oxime can be recovered from the leachate. The oxime is recycled and the copper is sent to further processing.
[0047] In step 170, the metal(s) from the solvent extraction step 160 are purified by electrowinning. Electro winning, also called electroextraction, is an electrodeposition process where metals in solution are electrodeposited on an electrode surface. Electrowinning uses electroplating on a large scale - the resulting metals are said to be electrowon. The metal is deposited on the cathode (either in solid or in liquid form), while the anodic reaction is usually oxygen evolution. The most common electrowon metals are lead, copper, gold, silver, zinc, aluminium, chromium, cobalt, manganese,
and the rare-earth and alkali metals. For aluminium, this is the only production process employed.
[0048] Referring now to Figure 3, a specific embodiment of a method 300 for extracting copper from a copper sulfide-containing ore is illustrated. Such a method 300 includes a step 310 of providing a copper sulfide-containing ore. In one embodiment, the copper sulfide-containing ore may include the copper sulfide- containing ore includes at least one of copper sulfide (chalcocite and covellite) or copper iron sulfide (chalcopyrite and bornite).
[0049] Method 300 further includes a step 320 of contacting the copper sulfide- containing ore with an acidic, substantially abiotic leaching agent that includes Fe(III) and at least one enzyme capable of oxidizing Fe(II) to Fe(III). In one embodiment, the enzyme may be at least one of rusticyanin or cytochrome C442. A suitable example of such an enzyme is rusticyanin. In one embodiment, the enzyme has a concentration in the leaching process of about 1 ppm to about 1000 ppm. In one embodiment, the leaching solution further comprising one or more of a chaperone, a detergent, a polymer additive, or an electron transfer dye.
[0050] In one embodiment, the leaching agent may include silver ions in addition to Fe(III). Silver ions are capable of participating in chemical reactions to liberate copper from copper sulfate ore similarly to iron. In addition, because silver is highly toxic to most living organisms, the enzyme based processes described herein can use silver, whereas processes that uses bacterial consortia cannot use silver because the silver could kill some or all of the organisms in the consortia.
[0051] The method 300 further includes a step 330 of performing a leaching process wherein the enzyme is allowed to participate in one or more chemical reactions to
recover copper from the copper sulfate ore. The leaching process 330 produces a leachate in step 340 that includes copper recovered from the ore. The method 300 finally includes a step 350 of recovering copper metal from the leachate. The metal may, for example, be recovered from the leachate according to steps 150-170 described in reference to Figure 1.
[0052] The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Claims
1. A method of recovering a metal from a metal-containing ore, the method comprising:
performing a screening assay to identify at least one enzyme that is suitable for leaching the metal from the metal-containing ore;
contacting the metal-containing ore with a leaching agent that includes the at least one enzyme, wherein the leaching agent is substantially abiotic;
performing a leaching process with the leaching agent to leach the metal from the metal-containing ore;
producing at least one of a solid or liquid leachate from the leaching process, wherein the leachate includes the metal from the metal-containing ore; and
recovering the metal from the leachate.
2. The method of claim 1, wherein the screening assay comprises pre- synthysizing crystalline nano-scale mineral particles which represents, or otherwise approximates a composition of the metal-containing ore.
3. The method of claim 2, wherein the composition of the crystalline nano- scale mineral particles are approximately between 0.001 μιη to 0.1 μιη in diameter.
4. The method of claim 2, wherein the screening assay further comprises subjecting the crystalline nano-scale mineral particles to a solution to form a plurality of homogenous test assays, and separately combining the test assays with different enzymes to identify the at least one enzyme.
5. The method of claim 4, wherein the different enzymes used are previously subjected to random or site-specific mutagenesis.
6. The method of claim 4, wherein the screening assay step further comprises identifying colorometric, fhiorometric, or calorimetric changes within any of the test assays.
7. The method of claim 6, wherein the solution comprises one or more of the following for identifying colorometric changes:
a) ferrozine if the metal contains iron, copper, or cobalt;
b) cuprizone if the metal contains copper;
c) PAR if the metal contains zinc, nickel, cobalt, or copper.
8 The method of claim 6, wherein the solution comprises one or more of the following for identifying fluorometric changes:
a) monobromobimane if the metal contains thiols;
b) Fura-2 if the metal contains manganese, cobalt, zinc, copper, nickel, or cadmium.
9. The method of claim 6, wherein colorometric changes are identified with a photoelectric colorimeter or color standard comparison; fluorometric changes are identified with a flurometer; and calorimetric changes are identified using thermocouples or calorimeters.
10. The method of claim 1, wherein the at least one enzyme is configured to withstand conditions for leaching the metal-containing ore during the leaching process.
11. The method of claim 1, wherein contacting the metal-containing ore with a leaching agent that includes the at least one enzyme further comprises provide at least one non-biocatalyst.
12. The method of claim 11, wherein the at least one non-biocatalyst comprises light waves, microwaves, or radiowaves.
13. The method of claim 12, wherein the at least one enzyme comprises a light-emitting enzyme, thereby providing in-situ photocatalysis throughout the leaching agent.
14. The method of claim 13, further comprising providing one or more organic cofactors with the at least one enzyme in the leaching agent.
15. The method of claim 1, wherein the at least one enzyme includes an iron oxidizing enzyme.
16. The method of claim 1, wherein the at least one enzyme includes at least one of a cupredoxin, a cytochrome, or an iron-sulfur protein.
17. The method of claim 1, wherein the at least one enzyme is at least one of rusticyanin or cytochrome C442.
18. The method of claim 1, wherein the metal-containing ore includes at least one of copper, nickel, zinc, molybdenum, gold, or silver.
19. The method of claim 12, further comprising: wherein the leaching agent includes Fe(III); and converting Fe(III) to Fe(II) to yield a soluble metal species from the metal- containing ore and the leaching process further includes enzymatically converting the Fe(II) produced in the leaching process back to Fe(III).
20. The method of claim 1, wherein the at least one enzyme has a concentration in the leaching agent of about 1 ppm to about 1000 ppm.
21. The method of claim 1, wherein the leaching agent includes one or more of a chaperone, a detergent, a polymer additive, or an electron transfer dye.
22. The method of claim 1, wherein the leaching agent exhibits one or more of:
a pH in a range of 0-4;
an ionic strength of up to and including the saturation point of the metal from the metal-containing ore; or
a temperature up to about 80 °C.
23. A leaching agent for recovering a metal from a metal-containing ore, comprising: an acid; and at least one enzyme associated with the acid and capable of promoting leaching the metal from the metal-containing ore; wherein the leaching agent is substantially abiotic.
24. The leaching agent of claim 23, further comprising at least one of Fe(III) or a silver ion, and wherein the at least one enzyme is capable of converting Fe(II) to Fe(III).
25. The leaching agent of claim 23 wherein the at least one enzyme includes at least one of a cupredoxin, a cytochrome, or an iron-sulfur protein.
26. The leaching agent of claim 25 wherein the at least one enzyme is at least one of rusticyanin or cytochrome C442.
27. The leaching agent of claim 23 wherein the at least one enzyme is derived from an organism selected from the group consisting of acidophiles, thermophiles, halophiles, and combinations thereof.
28. The leaching agent of claim 27 wherein the at least one enzyme is derived from Acidithiobacillus ferrooxidans .
29. The leaching agent of claim 27 wherein the at least one enzyme is isolated from a recombinant organism carrying one or more genes from an organism selected from the group consisting of acidophiles, thermophiles, halophiles, and combinations thereof.
30. The leaching agent of claim 23 wherein the leaching agent includes one or more of a chaperone, a detergent, a polymer additive, or an electron transfer dye.
31. The leaching agent of claim 23 wherein the at least one enzyme is selected to be active for recovering the metal from the metal-containing ore in an environment exhibiting one or more of:
a pH in a range of 0-4;
a high ionic strength up to and including a saturation point of the metal from the metal-containing ore; or
a temperature up to about 80 °C.
32. The leaching agent of claim 31 wherein the at least one enzyme includes a recombinant enzyme selectively engineered to be active for recovering the metal from the metal-containing ore in an environment exhibiting one or more of:
a pH in a range of 0-4;
a high ionic strength up to and including a saturation point of the metal from the metal-containing ore; or
a temperature up to about 80 °C.
33. A method of recovering copper from a copper sulfide-containing ore, the method comprising:
contacting the copper sulfide-containing ore with an acidic, substantially abiotic leaching agent that includes Fe(III) and at least one enzyme capable of oxidizing Fe(II) to Fe(III);
performing a leaching process with the acidic, substantially abiotic leaching agent to leach the copper from the copper sulfide-containing ore;
producing at least one of a solid or liquid leachate from the leaching process, wherein the leachate includes the copper from the copper sulfide-containing ore; and recovering copper metal from the leachate.
34. The method of claim 33, wherein the at least one enzyme includes at least one of rusticyanin or cytochrome C442.
35. The method of claim 33, wherein the copper sulfide-containing ore includes at least one of copper sulfide (chalcocite and covellite) or copper iron sulfide (chalcopyrite and bornite).
36. The method of claim 33, wherein the at least one enzyme has a concentration in the acidic, substantially abiotic leaching agent of about 1 ppm to about 1000 ppm.
37. The method of claim 33, wherein the acidic, substantially abiotic leaching agent includes one or more of a chaperone, a detergent, a polymer additive, or an electron transfer dye.
38. The method of claim 33, wherein the acidic, substantially abiotic leaching agent includes silver ions.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201261746710P | 2012-12-28 | 2012-12-28 | |
US61/746,710 | 2012-12-28 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2014105944A1 true WO2014105944A1 (en) | 2014-07-03 |
Family
ID=51022057
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2013/077790 WO2014105944A1 (en) | 2012-12-28 | 2013-12-26 | Use of enzymes for recovering a metal from a metal-containing ore |
Country Status (1)
Country | Link |
---|---|
WO (1) | WO2014105944A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113355519A (en) * | 2021-06-03 | 2021-09-07 | 上海第二工业大学 | Method for leaching copper in waste circuit board by using microwave-enhanced thiobacillus ferrooxidans |
CN114854989A (en) * | 2022-04-27 | 2022-08-05 | 江苏师范大学 | Method for enhancing leaching of active substances of positive electrode of waste lithium ion battery through photocatalysis |
CN115287453A (en) * | 2022-06-29 | 2022-11-04 | 中南大学 | Method for enhancing chalcopyrite bioleaching by flotation collector |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4497778A (en) * | 1981-04-06 | 1985-02-05 | University College Cardiff Consultants Limited | Microbial leaching of sulphide-containing ores |
US5030426A (en) * | 1989-06-27 | 1991-07-09 | Technical Research, Inc. | Biomining of gallium and germanium containing ores |
US5766478A (en) * | 1995-05-30 | 1998-06-16 | The Regents Of The University Of California, Office Of Technology Transfer | Water-soluble polymers for recovery of metal ions from aqueous streams |
US5898002A (en) * | 1997-08-22 | 1999-04-27 | Betzdearborn Inc. | Method for removing ferric-ferrous oxides from a liquid |
US20040038354A1 (en) * | 2000-11-25 | 2004-02-26 | Dew David William | Bioproduct production during oxidisation of metal sulphide minerals by means of microorganisms |
US20050124021A1 (en) * | 2000-06-14 | 2005-06-09 | Newton Gerald L. | Acetyl glucosaminyl inositol deacetylase, a mycothiol biosynthetic enzyme, and methods of use |
US20080069723A1 (en) * | 2006-09-20 | 2008-03-20 | Hw Advanced Technologies, Inc. | Method for oxidizing carbonaceous ores to facilitate precious metal recovery |
US20080207462A1 (en) * | 2005-11-21 | 2008-08-28 | Biosigma S.A. | DNA fragments array from biomining microorganisms and method for detection of them |
US20120237606A1 (en) * | 2009-09-16 | 2012-09-20 | Spheritech Ltd | Hollow particulate body |
-
2013
- 2013-12-26 WO PCT/US2013/077790 patent/WO2014105944A1/en active Application Filing
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4497778A (en) * | 1981-04-06 | 1985-02-05 | University College Cardiff Consultants Limited | Microbial leaching of sulphide-containing ores |
US5030426A (en) * | 1989-06-27 | 1991-07-09 | Technical Research, Inc. | Biomining of gallium and germanium containing ores |
US5766478A (en) * | 1995-05-30 | 1998-06-16 | The Regents Of The University Of California, Office Of Technology Transfer | Water-soluble polymers for recovery of metal ions from aqueous streams |
US5898002A (en) * | 1997-08-22 | 1999-04-27 | Betzdearborn Inc. | Method for removing ferric-ferrous oxides from a liquid |
US20050124021A1 (en) * | 2000-06-14 | 2005-06-09 | Newton Gerald L. | Acetyl glucosaminyl inositol deacetylase, a mycothiol biosynthetic enzyme, and methods of use |
US20040038354A1 (en) * | 2000-11-25 | 2004-02-26 | Dew David William | Bioproduct production during oxidisation of metal sulphide minerals by means of microorganisms |
US20080207462A1 (en) * | 2005-11-21 | 2008-08-28 | Biosigma S.A. | DNA fragments array from biomining microorganisms and method for detection of them |
US20080069723A1 (en) * | 2006-09-20 | 2008-03-20 | Hw Advanced Technologies, Inc. | Method for oxidizing carbonaceous ores to facilitate precious metal recovery |
US20120237606A1 (en) * | 2009-09-16 | 2012-09-20 | Spheritech Ltd | Hollow particulate body |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113355519A (en) * | 2021-06-03 | 2021-09-07 | 上海第二工业大学 | Method for leaching copper in waste circuit board by using microwave-enhanced thiobacillus ferrooxidans |
CN114854989A (en) * | 2022-04-27 | 2022-08-05 | 江苏师范大学 | Method for enhancing leaching of active substances of positive electrode of waste lithium ion battery through photocatalysis |
CN114854989B (en) * | 2022-04-27 | 2024-05-24 | 江苏师范大学 | Method for leaching anode active material of photocatalytic reinforced waste lithium ion battery |
CN115287453A (en) * | 2022-06-29 | 2022-11-04 | 中南大学 | Method for enhancing chalcopyrite bioleaching by flotation collector |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN100471947C (en) | Bacterial strain for leaching out ore or clean ore comprising metallic sulfide ore component and leaching method thereof | |
Lee et al. | Bio-processing of solid wastes and secondary resources for metal extraction–a review | |
Mohanty et al. | A review of biotechnology processes applied for manganese recovery from wastes | |
Morin et al. | Bioleaching of a cobalt-containing pyrite in stirred reactors: a case study from laboratory scale to industrial application | |
RU2483127C1 (en) | Method of processing refractory gold-bearing pyrrotine-arsenopyrite ore | |
Rawlings | Industrial practice and the biology of leaching of metals from ores The 1997 Pan Labs Lecture | |
Adams et al. | Biogenic sulphide for cyanide recycle and copper recovery in gold–copper ore processing | |
Brierley | Mining biotechnology: research to commercial development and beyond | |
Agate | Recent advances in microbial mining | |
Mishra et al. | Biotechnological avenues in mineral processing: Fundamentals, applications and advances in bioleaching and bio-beneficiation | |
Ahn et al. | Comparative investigations on sulfidic gold ore processing: A novel biooxidation process option | |
CN105986119B (en) | Polymeric support for leaching mineral concentrates and method | |
WO2014105944A1 (en) | Use of enzymes for recovering a metal from a metal-containing ore | |
CN100404705C (en) | Method for extracting metal copper using microbe and its use | |
Ubaldini et al. | Treatment of secondary raw materials by innovative processes | |
Miller et al. | Commercialization of bioleaching for base-metal extraction | |
Morin et al. | Progress after three years of BioMinE—Research and Technological Development project for a global assessment of biohydrometallurgical processes applied to European non-ferrous metal resources | |
Das et al. | Manganese mining microorganisms | |
Torma et al. | Bioliberation of gold | |
Natarajan | Biotechnology in gold processing | |
Natarajan | Bioprocessing for enhanced gold recovery | |
Chaerun et al. | Biohydrometallurgy: paving the way for a greener future of mineral processing in Indonesia-A mini review | |
Mora et al. | Industrial Biotechnology and its Role in the Mining Industry | |
Duarte et al. | Biotreatment of tailings for metal recovery | |
Senthil Kumar et al. | Biomining of natural resources |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 13868598 Country of ref document: EP Kind code of ref document: A1 |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 13868598 Country of ref document: EP Kind code of ref document: A1 |