WO2014105679A1 - Compositions et procédés de lixiviation de minerais - Google Patents

Compositions et procédés de lixiviation de minerais Download PDF

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Publication number
WO2014105679A1
WO2014105679A1 PCT/US2013/076826 US2013076826W WO2014105679A1 WO 2014105679 A1 WO2014105679 A1 WO 2014105679A1 US 2013076826 W US2013076826 W US 2013076826W WO 2014105679 A1 WO2014105679 A1 WO 2014105679A1
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WO
WIPO (PCT)
Prior art keywords
leaching
heap
sulfide
promoter
ore
Prior art date
Application number
PCT/US2013/076826
Other languages
English (en)
Inventor
David J. Chaiko
Sara ROCKS (Sally)
Original Assignee
Flsmidth A/S
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Flsmidth A/S filed Critical Flsmidth A/S
Publication of WO2014105679A1 publication Critical patent/WO2014105679A1/fr

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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

Definitions

  • This invention relates to methods and systems for leaching metals from metal sulfide ores and concentrates, and more particularly to methods and systems for the improved recovery of base and precious metals during leaching of metal values from ores and concentrates.
  • the present invention is utilized in the process known as heap leaching.
  • Heap leaching is an industrial mining process used to extract precious metals, such as copper, uranium, and other metals from ore via a series of chemical reactions that dissolve specific minerals and then separate the dissolved metals from each other after their division from other earth materials.
  • heap leach mining differs in that it uses a liner to place amounts of ore on, then adds the chemicals via drip systems to the ore, whereas in situ mining lacks these pads and pulls pregnant solution up to obtain the metals.
  • Heap leaching comprises in part the process steps of:
  • a typical heap is routinely open to the air and can be 30 or more feet high, 100 feet or more in width, and up to about 2,500 feet in length; and (iii) performing a leaching step which entails percolating a solution containing a leaching agent such as a lixiviant, sulfuric acid, bacteria etc. through the heap.
  • a leaching agent such as a lixiviant, sulfuric acid, bacteria etc.
  • the heap site can be provided with an overhead sprinkler system or other means to introduce the desired solution(s) at the top of the heap, and a pad at the bottom.
  • the heap may be engineered to improve production efficiency and speed metal recovery by providing a means to introduce the leaching agent(s) throughout the heap at intermediate levels during its construction.
  • the treatment fluids are sprinkled (or sprayed, flooded, emitted or otherwise applied) over the heap, and then they percolate or seep through the heap.
  • the percolation generally is unassisted gravitational flow and when the treatment fluids reach the bottom pad, they drain or run off to the side to a pond or reservoir.
  • the bottom pad must be impervious or inert to the treatment fluid(s) being used, and is commonly formed of polyethylene, and at times of compacted clay.
  • Heap leaching is an accepted way to recover metal values from an ore, in that the capital cost requirements are less than for alternative leaching methods such as agitated tank leaching. Operating costs are also generally lower for heap leaching than agitated tank leaching, due to reduced equipment and manpower requirements. In addition, heap leaching is usually conducted using a coarser size material fraction than agitated tank leaching, thus reducing power requirements and reagent consumption.
  • Bioleaching which comprises adding microbial cultures containing specially selected bacteria to the heap, generally in conjunction with a dilute sulfuric acid solution, is well known.
  • the bacterial bioagents typically used in the solution are Acidithiobacillus microorganisms. While other microbes, including bacteria, are naturally present in the heap, adding cultures of specifically chosen microbes to the heap has been advanced as an improvement over other heap leaching methods. However, bioleaching is too slow kinetically to be completely accepted by the industry. This is because there are inherent inefficiencies associated with bacterial-assisted leaching. The bacteria first and foremost utilize reactions to aid their own growth and metabolism.
  • FIG. 1 is a schematic diagram of a conventional heap leach operation adaptable for use in the present invention.
  • a heap leaching process is augmented by adding, preferably during the during agglomeration step, a leaching promoter comprising (a) sulfide oxidizing bacteria and (b) a sulfide oxidizing promoting material comprising at least one of (i) quorum sensing molecules specific to the sulfide oxidizing bacteria and (ii) an industrial enzyme.
  • a leaching promoter comprising (a) sulfide oxidizing bacteria and (b) a sulfide oxidizing promoting material comprising at least one of (i) quorum sensing molecules specific to the sulfide oxidizing bacteria and (ii) an industrial enzyme.
  • a heap leaching process is augmented by adding, preferably during agglomeration, an leaching promoter comprising (a) sulfide/ferrous oxidizing bacteria and (b) a sulfide/ferrous oxidizing promoting material comprising at least one of (i) quorum sensing molecules specific to the sulfide oxidizing bacteria and (ii) an industrial enzyme.
  • the heap leaching process being augmented utilizes a leaching promoter during the agglomeration step in concert with inserting a bioleaching solution containing an appropriate biological leaching agent, such as Acidithiobacillus microorganisms, throughout the heap.
  • the components of the leaching promoter are further defined as follows:
  • the sulfide/ferrous oxidizing bacteria suitable for use in the leaching promoter include Acidithiobacillus ferrooxidans; Acidithiobacillus thiooxidans; Acidithiobacillus caldus; Acidithiobacillus ferrivorans; Acidithiobacillus organoparus; and Acidithiobacillus acidphilus.
  • Other bacteria which may be utilized in the leaching promoter include: Sulfobacillus ferrooxidans; Acidithiobacillus thiooxidans; Acidithiobacillus caldus; Acidithiobacillus ferrivorans; Acidithiobacillus organoparus; and Acidithiobacillus acidphilus.
  • Other bacteria which may be utilized in the leaching promoter include: Sulfobacillus
  • thermosulfidooxidans Sulfolobus acidocaldarius, Sulfolobus BC; Sulfolobus solfataricus;
  • Acidanus brierley; and Lepto spirillum ferrooxidans are indigenous to the ore being leached. These bacteria are delivered in a solution having a low pH, such as dilute sulfuric acid. The pH may range from about 0.3 to 4.
  • the term "industrial enzyme(s)" as used herein refers to oxidizing enzymes that are produced by industrial processes such as submerged fermentation or solid state fermentation. The thus-produced enzymes are subsequently subject to isolation and optional purification.
  • the enzyme for use in the present invention will typically be in the form of an aqueous dispersion or alternatively a lyophilized powder.
  • Examples of enzymes suitable for use in the present invention are (1) cupredoxins such as amicyanin, plastocyanin, pseudoazurin, plantacyanin, azurin, auracyanin, rusticyanin, stellacyanin, and mavicyanin; cytochromes such as cytochrome c4, which is capable of re-oxidizing the cupredoxin; and iron-sulfur proteins such as a [4Fe-4S] protein having a redox potential high enough to either oxidize ferrous iron or regenerate partner electron transfer enzymes.
  • cupredoxins such as amicyanin, plastocyanin, pseudoazurin, plantacyanin, azurin, auracyanin, rusticyanin, stellacyanin, and mavicyanin
  • cytochromes such as cytochrome c4, which is capable of re-oxidizing the cupredoxin
  • iron-sulfur proteins such as a [4Fe-4S] protein having
  • the redox potential of the lixivant may be controlled to a desired optimum by admixing ferric/ferrous salts at a predetermined ferric to ferrous ratio to the dilute sulfuric acid. It will be recognized by one skilled in the art that the redox potential may purposefully be adjusted at different stages during the life of the heap to maximize both the metal recovery and the rate of metal recovery.
  • Quorum sensing molecules is used herein to designate signal molecules that promote group behavior in bacteria, and are small poly-peptides and can be synthesized cheaply and in abundance.
  • the quorum sensing molecules utilized in the present process will be chosen for their specificity to the bacteria that is utilized in the leaching promoter and/or the bacteria population that is indigenous to the heap.
  • Acidithiobacillus ferrooxidans a major component of bacterial population in the heap and also one possible sulfide/ferrous oxidizing bacteria for utilization in the invention's leaching promoter, utilizes N-acyl homoserine lactone as a quorum sensing molecules to promote biological attachment to mineral surfaces and to enhance the formation of biofilms in the ore.
  • the leaching promoter of the present invention can be delivered to the in heap leaching process in a single stream.
  • bacteria and an industrial enzyme are both used in the leaching promoter they be delivered to the heap leaching process in separate streams, with the proviso that such delivery be essentially simultaneous.
  • quorum sensing molecules when quorum sensing molecules are utilized in the leaching promoter, with or without the use of an industrial enzyme, it is preferred that the quorum sensing molecules be in solution with the bacteria.
  • industrial enzymes When industrial enzymes are applied in a separate solution, it may be an aqueous or acidic solution.
  • the invention can be utilized to promote metal recovery from metal producing ores such as conventional sulfide ores, refractory gold ores, and sulfidic/carbonaceous double refractory gold ores.
  • chalcopyrite the primary copper-containing mineral found in the majority of the copper sulfide ores, is suitable for processing per the present invention.
  • suitable copper-containing ore minerals include chalcocite (Cu 2 S), bornite (Cu 5 FeS 4 ), covellite (CuS), digenite (Cu 2 S), enargite (Cu 3 AsS 4 ), tennantite (Cu 12 As 4 S 13 ), and tetrahedrite
  • Suitable low grade gold ores may include, for example, Calaverite, Sylanite, Nagyagite, Petzite , Krennerite, and other alluvial or oxide-type deposits.
  • FIG. 1 illustrates a conventional heap leach circuit 1 suitable for use in the present invention.
  • the circuit incorporates a feed stream 2 of ore, which is subject to size reduction such as by being crushed in a cone-crusher 3 to thereby form a crushed ore 4.
  • the particles are moved via first conveying means 5 to an agglomerator 13.
  • a polymeric binder is added to the agglomerator via inlet 15.
  • the agglomerator 13 lumps the various particle size distributions within the crushed ore 4 into larger agglomerated balls 19 which are typically coin-sized.
  • the leaching promoter jump starts the bioleaching process within the aggolmerator.
  • agglomerated balls 19 are moved (via secondary conveying means 17) as agglomerated feed 14 to a heap leach pad 16 having an impermeable pad liner 9 thereunder.
  • Leach solution 7, (which can be sulfuric acid, lixiviant, cyanide solution or thiosulfate, but in the most preferred embodiment is a bioleach solution) is delivered via a delivery system 6 comprising drip/spray irrigation nozzles 12. As the leach solution 7 trickles through top 8a, middle 8b, and bottom 8c layers of the heap leach pad 16, it passes between the spaces and interstices created by the larger stacked agglomerated balls 19.
  • target metals dissolve into the leach solution 7 thereby forming a pregnant leach solution 10, which may be recycled to the nozzles 12 or removed for further downstream processing.
  • pregnant leach solution 10 from the heap 16 is moved to a conventional solvent extraction process.
  • the leaching promoter of the invention is added via inlet 15 or another inlet to agglomerator 13.
  • the leaching process will begin immediately prior to the material reaching the leach pad as opposed to prior art methods where an induction period is required before the bacteria begin to thrive.
  • the leach promoter can alternatively or additionally be added to the heap via a delivery system. If a bioleach solution is being utilized bacteria is already being added to the heap, and therefore the quorum sensing molecules and/or the industrial enzymes can be added to the heap in addition to the bioleach solution to provide for augmented leaching.
  • the bacteria, quorum sensing molecules and industrial enzymes are all present in their respective solutions in concentrations ranging from about 1 ppm to about 1000 ppm.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Biotechnology (AREA)
  • Microbiology (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Biochemistry (AREA)
  • Geology (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

L'invention concerne un promoteur de lixiviation utilisé pendant la lixiviation en tas de minerais sulfurés. Le promoteur contient une bactérie oxydant le soufre/le fer et un matériau favorisant l'oxydation du soufre/du fer comprenant (i) des molécules de détection du quorum et/ou (ii) une enzyme industrielle.
PCT/US2013/076826 2012-12-27 2013-12-20 Compositions et procédés de lixiviation de minerais WO2014105679A1 (fr)

Applications Claiming Priority (2)

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US201261746371P 2012-12-27 2012-12-27
US61/746,371 2012-12-27

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WO2014105679A1 true WO2014105679A1 (fr) 2014-07-03

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014201507A1 (fr) * 2013-06-21 2014-12-24 Technological Resources Pty. Limited Dérivés de lactone homosérine pour améliorer l'extraction des éléments minéraux pendant l'extraction biologique de minerais

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110045581A1 (en) * 2009-08-20 2011-02-24 Biosigma S.A. Bioreactor for continuous production of bioleaching solutions for inoculation and irrigation of sulfide-ore bioleaching heaps and dumps
US8119085B2 (en) * 2005-03-21 2012-02-21 Bioheap Limited Heap leaching of sulphide ores

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8119085B2 (en) * 2005-03-21 2012-02-21 Bioheap Limited Heap leaching of sulphide ores
US20110045581A1 (en) * 2009-08-20 2011-02-24 Biosigma S.A. Bioreactor for continuous production of bioleaching solutions for inoculation and irrigation of sulfide-ore bioleaching heaps and dumps

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
BRANDL, H.: "8 Microbial Leaching of Metals", 24 May 2003 (2003-05-24), ZURICH, SWITZERLAND, pages 195 - 197, Retrieved from the Internet <URL:http://www.wiley-vchde/books/biotech/pdf/v10_bran.pdf> [retrieved on 20140314] *
GONZALES, A ET AL.: "AHL Signaling Molecules with a Large Acyl Chain Enhance Biofilm Formation on Sulfur and Metal Sulfides by the Bioleaching Bacterium Acidithiobacillus Ferrooxidans'';", vol. 97, 3 July 2012 (2012-07-03), pages ABST.3730 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014201507A1 (fr) * 2013-06-21 2014-12-24 Technological Resources Pty. Limited Dérivés de lactone homosérine pour améliorer l'extraction des éléments minéraux pendant l'extraction biologique de minerais

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