AU618177B2 - Biological oxidation of sulfide ore - Google Patents
Biological oxidation of sulfide ore Download PDFInfo
- Publication number
- AU618177B2 AU618177B2 AU52258/90A AU5225890A AU618177B2 AU 618177 B2 AU618177 B2 AU 618177B2 AU 52258/90 A AU52258/90 A AU 52258/90A AU 5225890 A AU5225890 A AU 5225890A AU 618177 B2 AU618177 B2 AU 618177B2
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- strain
- ferrooxidans
- strains
- slurry
- thiobacillus
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- 230000003647 oxidation Effects 0.000 title claims description 23
- 238000007254 oxidation reaction Methods 0.000 title claims description 23
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 title claims description 8
- 241000605222 Acidithiobacillus ferrooxidans Species 0.000 claims description 29
- 238000000034 method Methods 0.000 claims description 29
- 239000002002 slurry Substances 0.000 claims description 18
- 239000007787 solid Substances 0.000 claims description 18
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 16
- 229910052737 gold Inorganic materials 0.000 claims description 16
- 239000010931 gold Substances 0.000 claims description 16
- 239000002184 metal Substances 0.000 claims description 8
- 229910052751 metal Inorganic materials 0.000 claims description 8
- 241000605272 Acidithiobacillus thiooxidans Species 0.000 claims description 5
- 241000589921 Leptospirillum ferrooxidans Species 0.000 claims description 5
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 4
- 239000011707 mineral Substances 0.000 claims description 4
- 238000005065 mining Methods 0.000 claims description 3
- 150000002739 metals Chemical class 0.000 claims description 2
- 108020004414 DNA Proteins 0.000 description 16
- 239000000243 solution Substances 0.000 description 10
- 241000894006 Bacteria Species 0.000 description 9
- 108091008146 restriction endonucleases Proteins 0.000 description 9
- 239000012141 concentrate Substances 0.000 description 8
- 108090000623 proteins and genes Proteins 0.000 description 7
- 239000013611 chromosomal DNA Substances 0.000 description 6
- 239000012634 fragment Substances 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 230000001580 bacterial effect Effects 0.000 description 5
- 238000009396 hybridization Methods 0.000 description 5
- 239000000523 sample Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 238000000605 extraction Methods 0.000 description 4
- NIFIFKQPDTWWGU-UHFFFAOYSA-N pyrite Chemical compound [Fe+2].[S-][S-] NIFIFKQPDTWWGU-UHFFFAOYSA-N 0.000 description 4
- 229910052683 pyrite Inorganic materials 0.000 description 4
- 239000011028 pyrite Substances 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 108020003215 DNA Probes Proteins 0.000 description 3
- 239000003298 DNA probe Substances 0.000 description 3
- 108090000790 Enzymes Proteins 0.000 description 3
- 102000004190 Enzymes Human genes 0.000 description 3
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 3
- 108091028043 Nucleic acid sequence Proteins 0.000 description 3
- 238000002105 Southern blotting Methods 0.000 description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical class [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 210000000349 chromosome Anatomy 0.000 description 3
- 230000029087 digestion Effects 0.000 description 3
- 239000000499 gel Substances 0.000 description 3
- 238000002955 isolation Methods 0.000 description 3
- 239000012528 membrane Substances 0.000 description 3
- 235000010755 mineral Nutrition 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- 102000053602 DNA Human genes 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 2
- 239000004677 Nylon Substances 0.000 description 2
- 241000605118 Thiobacillus Species 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- 239000011543 agarose gel Substances 0.000 description 2
- 229910052785 arsenic Inorganic materials 0.000 description 2
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 2
- 229910052964 arsenopyrite Inorganic materials 0.000 description 2
- MJLGNAGLHAQFHV-UHFFFAOYSA-N arsenopyrite Chemical compound [S-2].[Fe+3].[As-] MJLGNAGLHAQFHV-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- AIYUHDOJVYHVIT-UHFFFAOYSA-M caesium chloride Chemical compound [Cl-].[Cs+] AIYUHDOJVYHVIT-UHFFFAOYSA-M 0.000 description 2
- 210000004027 cell Anatomy 0.000 description 2
- 229910000358 iron sulfate Inorganic materials 0.000 description 2
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 230000035772 mutation Effects 0.000 description 2
- 150000002825 nitriles Chemical class 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 235000015097 nutrients Nutrition 0.000 description 2
- 229920001778 nylon Polymers 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 239000013612 plasmid Substances 0.000 description 2
- 229910052952 pyrrhotite Inorganic materials 0.000 description 2
- 230000002285 radioactive effect Effects 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- 108010072454 CTGCAG-specific type II deoxyribonucleases Proteins 0.000 description 1
- 241000723346 Cinnamomum camphora Species 0.000 description 1
- 108010067770 Endopeptidase K Proteins 0.000 description 1
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 1
- MBMLMWLHJBBADN-UHFFFAOYSA-N Ferrous sulfide Chemical class [Fe]=S MBMLMWLHJBBADN-UHFFFAOYSA-N 0.000 description 1
- 241000589925 Leptospirillum Species 0.000 description 1
- 235000019738 Limestone Nutrition 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 101000702488 Rattus norvegicus High affinity cationic amino acid transporter 1 Proteins 0.000 description 1
- 108020004682 Single-Stranded DNA Proteins 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- 239000003929 acidic solution Substances 0.000 description 1
- 238000005273 aeration Methods 0.000 description 1
- 238000000246 agarose gel electrophoresis Methods 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 238000000376 autoradiography Methods 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000013592 cell lysate Substances 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- DVRDHUBQLOKMHZ-UHFFFAOYSA-N chalcopyrite Chemical compound [S-2].[S-2].[Fe+2].[Cu+2] DVRDHUBQLOKMHZ-UHFFFAOYSA-N 0.000 description 1
- 229910052951 chalcopyrite Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000002759 chromosomal effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910001779 copper mineral Inorganic materials 0.000 description 1
- 230000009089 cytolysis Effects 0.000 description 1
- 238000000502 dialysis Methods 0.000 description 1
- MOTZDAYCYVMXPC-UHFFFAOYSA-N dodecyl hydrogen sulfate Chemical compound CCCCCCCCCCCCOS(O)(=O)=O MOTZDAYCYVMXPC-UHFFFAOYSA-N 0.000 description 1
- ZMMJGEGLRURXTF-UHFFFAOYSA-N ethidium bromide Chemical compound [Br-].C12=CC(N)=CC=C2C2=CC=C(N)C=C2[N+](CC)=C1C1=CC=CC=C1 ZMMJGEGLRURXTF-UHFFFAOYSA-N 0.000 description 1
- 229960005542 ethidium bromide Drugs 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000011790 ferrous sulphate Substances 0.000 description 1
- 235000003891 ferrous sulphate Nutrition 0.000 description 1
- 230000001605 fetal effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000004545 gene duplication Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000003306 harvesting Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 1
- 235000019341 magnesium sulphate Nutrition 0.000 description 1
- 229910052976 metal sulfide Inorganic materials 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000002773 nucleotide Substances 0.000 description 1
- 125000003729 nucleotide group Chemical group 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- 238000004537 pulping Methods 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000010186 staining Methods 0.000 description 1
- 229910052569 sulfide mineral Inorganic materials 0.000 description 1
- 229910021653 sulphate ion Inorganic materials 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000013519 translation Methods 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
- 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
Description
COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION NAME ADDRESS OF APPLICANT: General Mining, fetals and Minerals Limited 74-78 Marshall St eet Johannesburg Trans :al Republic of South Africa 0o a NAME(S) OF INVENTOR(S): Ellen Nanda LAWSON SNicolaas Hendrik HOLDER 0. Michiel Ptrus CAMPHER ADDRESS FOR SERVICE: DAVIES COLLISON Patent Attorneys I Little Collins Street, Melbourne, 3000.
S COMPLETE SPECIFICATION FOR THE INVENTION ENTITLED: Soo Biological oxidation of sulfide ore The following statement is a full description of this invention, including the best method of performing it known to me/us:- NM(S
FINETO()
la BACKGROUND OF THE INVENTION This invention relates to the recovery of metal such as gold from sulfide ores and is particularly concerned with the biological oxidation of such ores.
SUMMARY OF THE INVENTION 44 The invention provides a method of extracting metal from a S: 5 sulfide ore which includes the steps of making a slurry o \from the ore, subjecting the slurry to biological oxidation using Thiobacillus ferrooxidans, separating solids from the slurry, and recovering metal from the S* solids, the method being characterized in that Thiobacillus ferrooxidans at least mainly contains the strain TF-FC-1, as hereinafter defined.
Thiobacillus ferrooxidans strain TF-FC-1 was deposited by General Mining, Metals and Minerals Limited at AGAL on 20 March 1990 under accession No.N90/010723.
I Distinguishing Characteristics of TF-FC-1 '1A ~Thiobacillus ferrooxidans FC1 contains three cryptic plasmids of 4.5, 11.8 and 27.6 kb. When its chromosome was digested with restriction enzymes and probed with nif-HDK genes isolated from T.ferrooxidans ATCC 33020 the following results were obtained: 1) the BamH1 restriction enzyme gave three bands of approximate sizes: 4.3, 2.3 and 2.0 kb, i L L1 _~7 2) the EcoRV restriction enzyme gave three bands of approximate sizes: 4.0 and 1.1 kb, and 3) the PstI restriction enzyme gave four bands of approximate sizes: 7.6, 6.0, 3.5 and 2.6 kb.
*y 1
C,
CC Cr The metal may be gold and may be recovered from the solids using any appropriate technique. For example the gold may be recovered by pulping the solirs in water with the addition of cyanide salts. This dissolves the gold and the gold may then be recovered from solution using a zinc cementation or carbon adsorption technique, for example.
The oxidation step may take place at a pH of from 1.2 to and preferably at a pH of 1.7 to 1.8.
The oxidation step may take place at a temperature of from C to 45 C but preferably at a temperature of about 400C.
Preferably strains of Thiobacillus thiooxidans and of Leptospirillum ferrooxidans are used, in addition at least to the defined strain of TF-FC-1, in the oxidation step.
The strain TF-FC-1 may be purified and be present exclusively in the Thiobacillus ferrooxidans, or may be present with one or more other strains which are co-dominant.
i t C u C Y)o BRIEF DESCRIPTION OF THE DRAWINGS The invention is further described by way of example with
L~
j -lr U -3reference to the accompanying drawings in which: Figure 1 schematically depicts a method of extracting gold from a sulfide ore, using biological oxidation, in accordance with the invention, and Figures 2 and 3 illustrate banding patterns respectively obtained from a selected T.ferrooxidans strain designated TF-FC-1, as herein defined, and the T.ferrooxidans ATCC 33020 strain each probed with nif-HDK genes from ATCC 33020.
S: DESCRIPTION OF PREFERRED EMBODIMENT The process of the invention is applicable to the extraction of precious metal, and particularly gold, from ores and concentrates where the gold exists in occluded form. The following description is made firstly with refeience to the process steps involved and secondly with reference to the bacterial types which are used in the biological oxidation of the concentrates which contain the ore, and in particular with reference to the technique used to identify, or distinguish, the bacteria.
As has been indicated the invention is particularly 30 applicable to the extraction of gold which is locked in sulfide minerals such as pyrite, pyrrhotite, arsenopyrite and also sometimes in chalcopyrite and other copper minerals.
Referring to the accompanying drawing a slurry 10 of the ore concentrate is made in water to between 10% and solids. The slurry may for example arise from a milling or concentrating operation.
L
-4- The slurry is fed to a series of agitated tanks serving as reactors, designated 12 in the accompanying drawing. The number of tanks may vary according to requirement from one upwards and usually is between four and eight.
The slurry in each reactor is agitated by any appropriate means, designated by the numeral 16, for example using mechanically driven stirrers or air, so that the solids are kept in suspension. Air or oxygen, designated 18, is sparged into each reactor to provide the necessary dissolved oxygen for an aerobic bacterial process.
During the bacterial oxidation heat is generated and use is made of a heat exchanger 20, for example cooling coils, to maintain the temperature of each reactor in the range of from 20 C to 45°C but preferably at a temperature of about 40 0
C.
The bacterial oxidation process can be described as follows, referring for example to pyrite: 2 FeS 2 7 02 H 2 0-Fe(S0 4 3
H
2 So 1 s a o? I n r 30
!I
c- The pH of the slurry in the reactor is controlled by a unit 22 so that the acid which is generated in the aforementioned process can be neutralized. This may be achieved by adding lime to the slurry so that its pH is maintained at between 1,2 and 2,0 with an optimal pH value being from 1,7 to 1,8. The lime may be added as a slurry of slaked lime or limestone.
A small amount of nutrients such as ammonia, phosphate and potassium^-a-added to the slurry in any suitable form.
Mj I 71 'eVT0 11 'II; The slurry contains a mixture of three bacteria types, namely strains of Thiobacillus ferrooxidans, Thiobacillus thiooxidans and Leptospirillum ferrooxidans. Within the strains of Thiobacillus ferrooxidans the strain TF-FC-1 is predominant with other T.ferrooxidans strains being present in relatively small concentrations.
The slurry remains in the reactor tanks for several days.
Some concentrates are easy to oxidise and sufficient gold is released in less than 24 hours. For other concentrates, particularly of the mineral pyrite, the time required may 1, be as much as 6 to 8 days but usually 3 to 4 days is sufficient for most ores which are encountered. The efficiency of the bacteria used for oxidation is highly important in this regard. After oxidation the slurry is S" directed from each reactor tank to a series of settling tanks 24. In these tanks the solids 26 are collected and the acidic solution is separated from the solids. The solids may be repulped with water and again allowed to settle so that as much as possible of the acid solution is o' removed from the solids. Filtration can also be used to separate the solids from the solution.
Gold is recovered from the solids 26 using any appropriate ao technique, in a step which is designated 28 in the accompanying drawing. Gold may for example be recovered by o *0 repulping the solids in water with the addition of cyanide salts. This dissolves the gold and the gold is then recovered from solution by known methods such as zinc cementation or carbon adsorption.
The strains of Thiobacillus ferrooxidans which are principally responsible for the oxidation of the concentrate are selected strains which have been established through extensive trial and experiment as -6being highly suitable for this purpose. Initially the Thiobacillus ferrooxidans strains which were available were capable of tolerating arsenic in solution at the relatively low level of 1 gram per litre. Through selective techniques the arsenic resistance of the Thiobacillus ferrooxidans strains used has been increased to 15 grams per litre. The principal strain of T.ferrooxidans which is used is designated, in this specification, as TF-FC-1. This strain is identifiable, for the purposes of this specification, by the criteria referred to hereinbefore, under the heading "Distinguishing Characteristics of TF-FC-1".
It has in addition been found that the oxidation efficiency is increased by the presence of Leptospirillum ferrooxidans and Thiobacillus thiooxidans. These bacteria are characterized by their respective ability to oxidise either ferrous to ferric, or sulfide to sulphate, and morphologically, since Leptospirillum is a curved rod (0,4um x lum) and Thiobacillus is a straight rod.
The TF-FC-1 bacteria are short rods, 0,5 by 2um, but S 25 become much longer under stress conditions, such as high temperatures. They are strictly aerobic and autobrophic.
They obtain energy for growth by oxidizing both ferrous and sulphur compounds and grow well in liquid nutrient 'o media with ferrous sulphate or powdered sulphur as the 'o 3j energy source. They grow even better in the presence of metal sulphides such as pyrrhotite, arsenopyrite and pyrite, when approximately 80% become attached to the surface of the iron sulphides. The bacteria can utilize gaseous nitrogen as their nitrogen source and require carbon dioxide as a carbon source. They are motile and have a pH optimum of 2.
The Thiobacillus ferrooixdans bacterium is broadly defined -7in the literature. Strains from all over the world are called Thiobacillus ferrooxidans even though some strains can apparently be divided into distinct groupings based on DNA homology. The classification is based chiefly on the ability of the bacterium to grow autotrophically and to obtain energy from the oxidation of reduced ion and sulphur compounds in an acid environment. A general description of this type is however not appropriate in distinguishing the strain TF-FC-1 from any other strain of Thiobacillus ferrooxidans. For this reason a DNA fingerprinting technique has been used to distinguish the strain TF-FC-1 from other T.ferrooxidans strains.
DNA fingerprinting involves the isolation of chromosomal DNA from T.ferrooxidans, its digestion with restriction enzymes which recognize specific 6-base pair DNA sequences and the separation of the fragments produced according to their molecular weight, using agarose gel electrophoresis.
These fragments are then transferred to a solid membrane support (Southern blotting) and the two DNA strands of each fragment are separated. A DNA probe that has homology to all the bacterial strains being compared is labelled (with radioactive isotopes or non-radioactively) and the strands are separated. The strands of the labelled DNA probe are added to the chromosomal DNA on the solid support and double stranded DNA is allowed to reform. The labelled DNA probe will reanneal with some of the DNA on W° 3' the solid support providing that the DNA sequences are S similar. This will serve to identify those fragments of DNA that have a similar nucleotide sequence to the probe being used, The fragments are identified by exposure of the solid support to an X-ray film and a banding pattern that is characteristic of a given strain and restriction enzyme will be produced. Generally it is expected that the more distantly related strains are to each other, the more these banding patterns will vary and vice versa.
-8- DIAGRAMMATIC OUTLINE OF THE PRINCIPLE OF THE TECHNIQUE Strain 1 nif-HDK.genes 2.0kb 3.0kb chromosomal
DNA
PstI PstI PstI PstI DNA The result of the digestion of the chromosome of strain 1 with PstI (specific recognition sequence CTGCAG) and s: probing with the nif-HDK genes will be bands at 2.0, and 4.0kb. If in strain 2 one of the nucleotide sequences that constitute the second PstI site has changed, then the bands generated on digestion of the strain 2 chromosome with PstI and probing with the nif-HDK genes, will be altered to 6.0 and 3.0kb. This is because the second PstI site no longer has the recognition sequence CTGCAG.
By comparing the banding patterns for a set of different restriction enzymes, it is possible to distinguish a given o 5 strain from other isolates.
The banding process was repeated with various T.ferrooxidans isolates to verify the distinctiveness of the fingerprinting technique. For this purpose use was S3 made of a purified strain of TF-FC-1 and T.ferrooxidans strains isolated from different ore concentrates, and identified herein as TF-JH, TF-ME, TF-BMP, TF-TS, TF-BR and TF-EI. In each case the chromosomal DNA was digested with four restriction enzymes and probed with T.ferrooxidans ATCC 33020 nif-HDK genes. The resulting banding pattern configurations are summarized in Table 1.
On the basis of the banding patterns from the EcoRV and I I I l J -9- PstI enzymes, the TF-FC-1 strain was most closely related to the TF-BR and TF-BMP strains, and on the basis of the EcoRV enzyme to the TF-ME and TF-TS strains. The TF-FC-1 strain is however clearly different from these strains with respect to the EcoRI and 1,2 kb BamHI fragments.
All the banding patterns from the TF-BMP and TF-BR strains are the same and these two isolates appear to be identical. The TF-TS and TF-ME strains are similar though not identical (EcoRI and PstI patterns vary in some bands) and there is strong similarity between these two strains and the TF-BMP and TF-BR.
On the basis of these tests there appears to be a close relationship between the TF-EI and ATCC 33020 strains although it is clear that the EcoRI banding patterns are different in spite of the TF-EI EcoRI digest being only partial.
The TF-JH strain was only distantly related to any of the others.
The TF-FC-1 strain is distinguishable from the seven other strains investigated, although it is clearly most closely related to the TF-BMP and TF-BR strains. Tt is also related to the TF-ME and TF-TS strains.
The TF-FC-1 strain was in fact introduce" into the TF-BR, if TF-BMP, TF-ME and TF-TS populations, and this is borne out by the banding patterns. Nonetheless there are differences in the banding patterns which are due either to co-dominance of strains arising as the populations adapted to different types of ore concentrates, or alternatively the differences in probe patterns are possibly due to mutations. The TF-FC-1 strain was not introduced into the TF-EI and TF-JH populations.
-I
TABLE 1 TABLE COMPARING THE BANDS SIZES (IN kb) OF DIFFERENT T.FERR0UXIDANS STRAINS CUT WITH THE SAMlE FOUR RESTRICTION ENZYMES
ENZYMES
BamHI EcoRI EcoR\I PstI 4 STRA IN TF.-FC-1 4.3 11+ 4.8 7.6 2.3 3.8 4.0 1.1 2.6 ATCC 33020 11+ 12+ 5.7 2.7 2.8 0.6 1.6 0.8 TF-JH 5.2 11+ 4.9 6.6 4.4 7.71 4.4 3.2 7.2' 2.3 4.7* 3.7* TF-llE 4.3 5.2 4.8 2.2 3.8 4.0 6.6 1.2 3.4 1.1 TF-BMP 4.2 3.7 4.8 2.3 3.4 4.0 1.2 3.4 1.3 -11- EN ZYMPES BamHI EcoRI EcoRV Pst I
STRAIN
TF-FS 4.2 11+ 12+ 2.3 3.6 8.2' 6.2 1.25 5.91' 5.6 4.7' 4.2* 1 TF-BR 4.2 3.s 13+ 6.6 2.2 3.25 11+ 5.2 1.8 5.2* 2.9 1.1 4-Y* 2.3 3.8B* 1 TF-EI 11+ 11+ 6 5.2 2.8 0.85 4.4 1.6 2.7 0.85 2.3* 1 1 1 .2* 0.8 Probable partial digests are indicated with an asterisk.
Note: a large number of bands could also be the result of gene duplication.
-12-
METHODS
Cultivation of T.ferrooxidans strains Approximately 10ml of each T.ferrooxidans strain, drawn from a respective ore slurry, was inoculated into 5 litres of liquid iron sulfate medium. The cultures were incubated at 30 C with vigorous aeration until the ferrous iron was completely oxidized. Oxidation took up to seven days. The cells were harvested by centrifugation at 10 000 rpm for minutes.
Isolation of chromosomal DNA After harvesting, the cells were washed to remove ferric iron and lysed with proteinase K and SDS (lauryl sulphate). RNAse was added to destroy RNA present. The cell lysate was purified by dialysis and phenol extraction. Chromosomal DNA was precipitated with two volumes of ethanol and 1/10 volume Na-acetate.
Isolation of probe DNA The plasmid pIMP16, containing the cloned T.ferrooxidans nif-HDK genes, was extracted from its host using the alkaline lysis method of Ish-Horowicz and Burke. The oplasmid was separated from chromosomal DNA and debri on CsCl density gradients.
Southern Hybridization Agarose gel: After restriction enzyme digests of the DNA, the samples were electrophoresed on agarose gel. The gel was stained with ethidium bromide and photographed on a 254nm UV-transilluminator.
-13- Southern blotting: After staining, the DNA in the gel was denatured. The gel was placed on a glass plate and a Hybond nylon membrane was placed on top. The DNA was transferred to the membrane by capillary action. The transferred, single stranded DNA was fixed to the filter by a 5 minute exposure to UV light.
Nick translation: 500ng of probe DNA was radioactively 32 lu labelled with p using an Amersham nick translation-kit.
This was stored in a lead container at -2 0 C until needed.
Hybridization: The nylon filter was soaked in pre-hybridization solution before being subjected to the 11 hybridization reaction.
The radioactive probe was denatured by boiling and added to the reaction mixture. Hybridization was allowed to take place overnight. The filter was washed after hybridization.
Autoradiography: The filter was placed between two X-ray films and left for at least three days.
i2L -14- Iron sulfate medium 150g FeSO4.H20 water to 11 (pH 1.2) 3g KH 2
PO
4 3g (NH 4 2
SO
4 3g MgSO4.H20 water to 11 (pH 1.7) 5x solution 0. 0 44 0 51 medium: 11 5x 500ml 10x 3.51 watei 10x solution solution solution i P 30 It is apparent that the DNA fingerprinting technique described hereinbefore is repeatable and uniquely identifies the selected strain TF-FC-1, even when the strain is not in a purified form but present as a co-dominant strain, or possibly together with mutations, as is the case with the TF-BMP and TF-BR strains. This strain, as has been stated, is particularly efficient in the oxidation step in the gold extraction process described with reference to Figure 1. A taxonomic investigation of the equilibrium population of TF-FC-1 has revealed that it occurs together with other T.ferrooxidans strains and Thiobacillus thiooxidans and Leptospirillum ferrooxidans. As has been pointed out these bacteria enhance the oxidation efficiency.
Claims (8)
1. A method of extracting metal from a sulfide ore which includes the steps of making a slurry from the ore, subjecting the slurry to biological oxidation using Thiobacillus ferrooxidans, separating solids from the slurry, and recovering metal from the solids, which is characterized in that the Thiobacillus ferrooxidans at least mainly contains the strain TF-FC-1, as hereinbefore defined.
2. A method according to claim 1 wherein the oxidation step takes place at a pH of from 1.2 to a
3. A method according to claim 2 wherein the pH is from 1.7 to 1.8.
4. A method according to claim 1, 2 or 3 wherein the oxidation step takes place at a temperature of from 20 0 C to 45 C. 2aS
5. A method according to claim 4 wherein the temperature is of the order of 40 C.
6. A method according to any one of claims 1 to wherein strains of Thiobacillus thiooxidans and of Leptospirillum ferrooxidans are used, in addition at least to the defined strain TF-FC-1, in the oxidation step.
7. A method of extracting gold from a sulfide ore substantially as hereinbefore described with reference to the accompanying drawings.
8. A strain of Thiobacillus ferrooxidans TF-FC-1 as hereinbefore defined. I I- =bhi PUO thcrcc9-f------ d-ds-leeed- h erei n -oT a ny- DATED this 27th day of March 1990. GENERAL MINING, METALS AND MINERALS LIMITED By Its Patent Attorneys DAVIES COLLISON 'I 200 0 2 0 au
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU52258/90A AU618177B2 (en) | 1990-03-27 | 1990-03-27 | Biological oxidation of sulfide ore |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU52258/90A AU618177B2 (en) | 1990-03-27 | 1990-03-27 | Biological oxidation of sulfide ore |
Publications (2)
| Publication Number | Publication Date |
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| AU5225890A AU5225890A (en) | 1991-10-03 |
| AU618177B2 true AU618177B2 (en) | 1991-12-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU52258/90A Expired AU618177B2 (en) | 1990-03-27 | 1990-03-27 | Biological oxidation of sulfide ore |
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| AU (1) | AU618177B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU654322B2 (en) * | 1991-02-27 | 1994-11-03 | Mount Isa Mines Limited | Biological leaching of transition ores |
| AU680007B2 (en) * | 1993-08-20 | 1997-07-17 | Polifin Limited | Nutrient composition |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1992016667A1 (en) * | 1991-03-22 | 1992-10-01 | Bac Tech (Australia) Pty. Ltd. | Oxidation of metal sulfides using thermotolerant bacteria |
| US5873927A (en) * | 1997-05-16 | 1999-02-23 | Echo Bay Mines, Limited | Integrated, tank/heap biooxidation process |
| US6096113A (en) * | 1997-05-16 | 2000-08-01 | Echo Bay Mines, Limited | Integrated, closed tank biooxidation/heap bioleach/precious metal leach processes for treating refractory sulfide ores |
| DE19960132A1 (en) | 1999-12-14 | 2001-06-21 | Alexander Beckmann | Process for the extraction of copper and other metals |
| CN103909023B (en) * | 2012-12-28 | 2016-06-15 | 北京有色金属研究总院 | A kind of method utilizing microbial flotation method separation pyrite and mispickel |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU565144B2 (en) * | 1982-12-17 | 1987-09-03 | Cra Services Limited | Process |
| AU574818B2 (en) * | 1984-11-26 | 1988-07-14 | Giant Bay Biotech Inc. | Bioleaching fe prior to gold and silver recovery from sulphide ores |
| AU1892688A (en) * | 1987-07-18 | 1989-01-19 | Merck Patent Gesellschaft Mit Beschrankter Haftung | Oxazolidinones |
| AU592161B2 (en) * | 1986-03-13 | 1990-01-04 | Davy Mckee (Stockton) Limited | Extraction of metal values from ores or concentrates |
-
1990
- 1990-03-27 AU AU52258/90A patent/AU618177B2/en not_active Expired
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU565144B2 (en) * | 1982-12-17 | 1987-09-03 | Cra Services Limited | Process |
| AU574818B2 (en) * | 1984-11-26 | 1988-07-14 | Giant Bay Biotech Inc. | Bioleaching fe prior to gold and silver recovery from sulphide ores |
| AU592161B2 (en) * | 1986-03-13 | 1990-01-04 | Davy Mckee (Stockton) Limited | Extraction of metal values from ores or concentrates |
| AU1892688A (en) * | 1987-07-18 | 1989-01-19 | Merck Patent Gesellschaft Mit Beschrankter Haftung | Oxazolidinones |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU654322B2 (en) * | 1991-02-27 | 1994-11-03 | Mount Isa Mines Limited | Biological leaching of transition ores |
| AU680007B2 (en) * | 1993-08-20 | 1997-07-17 | Polifin Limited | Nutrient composition |
Also Published As
| Publication number | Publication date |
|---|---|
| AU5225890A (en) | 1991-10-03 |
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