WO2009083204A1 - Procédé amélioré pour la récupération de métal et recyclage d'agent de lixiviation dans des installations à lixiviation par agitation - Google Patents

Procédé amélioré pour la récupération de métal et recyclage d'agent de lixiviation dans des installations à lixiviation par agitation Download PDF

Info

Publication number
WO2009083204A1
WO2009083204A1 PCT/EP2008/010979 EP2008010979W WO2009083204A1 WO 2009083204 A1 WO2009083204 A1 WO 2009083204A1 EP 2008010979 W EP2008010979 W EP 2008010979W WO 2009083204 A1 WO2009083204 A1 WO 2009083204A1
Authority
WO
WIPO (PCT)
Prior art keywords
aqueous
solution
desired metal
leach
aqueous leach
Prior art date
Application number
PCT/EP2008/010979
Other languages
English (en)
Inventor
Andrew Nisbett
Original Assignee
Cognis Ip Management Gmbh
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
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=40377569&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=WO2009083204(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Cognis Ip Management Gmbh filed Critical Cognis Ip Management Gmbh
Priority to CA2711025A priority Critical patent/CA2711025C/fr
Priority to BRPI0821491-3A priority patent/BRPI0821491A2/pt
Priority to US12/811,285 priority patent/US20100282025A1/en
Priority to MX2010005024A priority patent/MX2010005024A/es
Priority to AU2008342921A priority patent/AU2008342921B2/en
Publication of WO2009083204A1 publication Critical patent/WO2009083204A1/fr
Priority to ZA2010/04346A priority patent/ZA201004346B/en

Links

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
    • 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
    • C22B15/0071—Leaching or slurrying with acids or salts thereof containing sulfur
    • 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
    • C22B15/0084—Treating solutions
    • 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
    • C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
    • C22B3/26—Treatment or purification of solutions, e.g. obtained by leaching by liquid-liquid extraction using organic compounds
    • 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

  • the present invention relates to the design and operation of the leaching and solvent extraction steps in a metal recovery plant for recovering desired metal values from mined ores containing such metal values possibly commingled with other metal values.
  • metals e.g., copper, nickel, cobalt, zinc, uranium, and the like
  • these metals must be removed and recovered from the ores in which they are found through a series of physical, hydrometallurgical and/or chemical steps.
  • the mined ore containing a greater or lesser amount of the desired metal value, in addition to possibly one or more other more-or-less desirable metal values and a large amount of gangue and other more-or-less complicating minerals, is leached with an aqueous acidic (commonly sulphuric acid) or basic (commonly ammonium hydroxide) solution.
  • aqueous acidic commonly sulphuric acid
  • basic commonly ammonium hydroxide
  • This leaching is accomplished by either distributing the leaching agent over a pile or bed of mostly dry ore solids in dump leaching, heap leaching or vat leaching, wherein these ores are either leached as mined, or they may be crushed, but not ground or milled, to a size that gives higher metal recovery and/or faster metal recovery, or, as in agitation leaching, by mixing the leaching agent with an aqueous slurry of crushed and milled ore solids in one or more stirred tanks in an attempt to ensure optimal distribution of the leaching solution throughout the ore solids.
  • crushed ore that is to be agitation- leached is generally ground or wet-milled to a desired size distribution for achieving an acceptable metal recovery in leaching, with the resulting ore solids being added to the agitation leach unit(s) as aqueous slurry.
  • agitation leaching a considerable amount of water is normally brought into the leaching system with the ore. This water must eventually leave or be removed from the system in order to maintain a water balance and it does so, mainly and continually, with the leached solids in the tailings or by intermittent bleeds from the circuit. Any desired metal or other valuable metals in the water leaving with the leached solids is lost (called the "soluble metal loss").
  • any leaching agent in this water is also lost and often has to be neutralized prior to the final disposal of the leached solids.
  • a dump or heap leach system is generally much less costly in both capital (equipment) costs and operating (energy) expense, and is therefore selected for use with lower grade ores, where costs are critical, or with higher grade ores that respond well to heap leaching, permitting a high metal recovery.
  • Agitation leaching provides for a faster and more complete recovery of the desired metal(s), is easier to control, and often gives higher recovery of secondary valuable metals, such as cobalt, but it is also more expensive due to the capital cost of additional equipment, such as mills, leach tanks and clarifiers, and has a higher operating cost because of, for example, the energy re- quired to mill the ore and the chemicals needed for the solids-liquid separation.
  • the resulting mix of aqueous leachate, now containing a high proportion of the desired metal values, as well as leached ore solids from which the desired metal values have been dissolved is then normally sent to a solids-liquid separation process, such as by counter-current decantation ("CCD"), with washing, or by filtration, also with washing.
  • CCD counter-current decantation
  • the clarified or partially-clarified aqueous phase is sent to one or more units in a solvent extraction process for transfer of the metal values from the aqueous leachate into an organic phase comprising one or more extraction re- agents.
  • the particular desired metal value is extracted from the leach solution containing that metal value into an organic phase by one or more extraction reagents specific for that desired metal, which reagent(s) is/are dissolved in an organic phase that comprises the extraction reagent(s), optionally with one or more equilibrium modifiers, kinetic additive(s) and/or other compounds, in a water-insoluble, water-immiscible organic solvent.
  • extraction reagents specific for that desired metal which reagent(s) is/are dissolved in an organic phase that comprises the extraction reagent(s), optionally with one or more equilibrium modifiers, kinetic additive(s) and/or other compounds, in a water-insoluble, water-immiscible organic solvent.
  • hydrogen ions are released from the organic phase into the aqueous phase, now largely depleted of the desired metal values, as represented by the equation below for extraction when copper is the desired metal, sulphuric acid is the leaching agent, and where "RH" represents the copper-specific extraction reagent(
  • the metal-rich organic phase containing one or more complexes of the desired metal with the extraction reagent(s) is then possibly washed to reduce the level of undesired iron and/or other undesirable species, and stripped of its desired metal content with a stripping agent, such as a relatively concentrated acid solution (normally sulphuric acid) that breaks apart the complex(es), freeing the desired metal into the aqueous "pregnant stripping solution".
  • a stripping agent such as a relatively concentrated acid solution (normally sulphuric acid) that breaks apart the complex(es), freeing the desired metal into the aqueous "pregnant stripping solution". That metal is then finally captured in a pure form from the desired metal-rich pregnant stripping solution, by electrodeposition in an electrowinning stage, or by one or more alternative metal recovery processes.
  • a particular issue addressed by this invention is the high cost both of replacing leaching agents lost or bled from the leaching-solvent extraction-electrowinning circuits and of purchasing substances used to neutralize excess leaching agents prior to further metal recovery activities and/or disposal of spent leaching and/or washing solutions containing these leaching agents.
  • Another issue addressed is the need to recover a higher percentage of the desired metal values from the leached ores and thereby reduce the amount of valuable metal that is ultimately lost from the circuit in bleed streams or to tailings disposal, resulting in the loss of significant revenue that could be realized by the operator.
  • Such washing is intended to minimize the loss of metal values with the disposal of the metal-depleted tailings slurry, but it also reduces the concentration of the desired metal in the clarified leach solution exiting solids-liquid separation and thereby reduces the leaching agent concentration which can build in this solution as the desired metal is extracted. Since only a portion of this leach solution, now depleted of desired metal values, but increased in leaching agent concentration, is recycled back to leaching, less leaching agent is recycled back to leaching than would be if the leaching solution had not been diluted.
  • the split circuit design involves subjecting the first leached pulp from the leach u- nit(s), comprising a mixture of metal-depleted leached solids and an aqueous leach solution containing dissolved salts of the desired metal, leaching agent, water, and possibly other metal values, to a first solids-liquid separation, without significant dilution.
  • the solids pulp from that separation is then sent to a second solids-liquid separation, with significant washing/dilution, with the clarified metal-rich aqueous leach solutions from each solids-liquid be- ing separation circulated to separate solvent extraction units.
  • the solids, as aqueous slurry, from the second solids-liquid separation are then sent to disposal, with the metal-depleted raffinate from the solvent extraction unit(s) following the first solids-liquid separation, without dilution, being recycled as leach solution, possibly supplemented with additional fresh leaching agent, to one or more of the leach unit(s).
  • the raffinate, depleted of desired metal values, exiting the solvent extraction unit(s) following the second solids-liquid separation is neutralized, as necessary, and/or circulated to one or more additional units to possibly recover other metal values that may also have been present in the original ore in sufficient quantities, and/or recycled back to the second solids-liquid separation as wash solution, with the possibility that some of the neutralized solution may be bled to disposal in order to maintain a water balance.
  • the present invention is directed to a process for leaching desired metal values from crushed and milled ore solids and extracting those values into organic phases for further recovery efforts, in order to eventually obtain the desired metal in a usable form.
  • This process initially comprises leaching crushed and milled ore solids with an acidic or basic leaching solution in one or more initial/"first" agitation leach units, to dissolve a significant portion of the desired metal values from the crushed and milled ore solids into an aqueous phase.
  • the slurry of partially-leached solids with aqueous leach solution (called a "leach pulp”) resulting from the initial leaching unit(s) proceeds to a first solids-liquid separation and clarification to produce two products, a first undiluted aqueous leach solution, rich in desired metal values, and a second leach pulp.
  • the first undiluted aqueous leach solution is then circulated, without significant dilution, to one or more "first" solvent extraction units for extracting the desired metal values from the aqueous solution into an organic phase.
  • first solvent extraction units for extracting the desired metal values from the aqueous solution into an organic phase.
  • the aqueous solution (“raffinate"), depleted of desired metal values, is recycled as leaching solution, possibly augmented by fresh leaching agent and/or recycled raffinate from one or more other solvent extractions later in the process/circuit, back to the initial leach unit(s).
  • the second leach pulp is sent, without significant dilution, to one or more "final" agitation leach units for additional leaching, in order to dissolve another significant portion of the desired metal values remaining in the pulp.
  • the leach pulp resulting from the "final" leach unit(s) is subjected to a second solids-liquid separation and clarification to produce two products, a second undiluted aqueous leach solution, rich in desired metal values, and a third leach pulp.
  • the second undiluted aqueous leach solution is circulated, without significant dilution, to one or more "second" solvent extraction units for extracting the desired metal values from the aqueous solution into an organic phase, with the aqueous solution ("raffinate"), depleted of desired metal values, exiting the second solvent extraction unit(s) being recycled as leaching solution, possibly augmented by fresh leaching agent and/or recycled raffinate from one or more other solvent extractions earlier and/or later in the process/circuit, back to the final agitation leach unit(s).
  • the third leach pulp now largely depleted of desired metal values after two teachings, is sent to a last solids-liquid separation, with water washing and significant dilution for the first time, from which the washed solids slurry is sent to disposal, and the clarified aqueous wash solution is sent to one or more final solvent extraction units.
  • the aqueous solution (raffi- nate), depleted of desired metal values is optionally neutralized and then either possibly sent to one of more units to recover any other valuable metal values also present in the original ore, or recycled back to the last solid-liquid separation unit(s) as wash solution, or it may be split, with some portion sent to recovery of other metal values, and some portion sent to recycle back to the last solids-liquid separation unit(s) as wash solution, and perhaps even some to final disposal.
  • the amount of leaching agent recycled to leach may be significantly increased, and both the amount of leached metal that is lost to tailings disposal and the quantities of additional fresh leaching agent purchased and the quantities of chemicals that must be expended to neutralize excess leaching agent in the circuits may be significantly decreased.
  • Each of these units then leaches desired metal values from the same ore solids, with each unit being followed by its own solids-liquid separator, without significant dilution, then its own solvent extraction unit(s), prior to a final solids-liquid separation, with washing, and a final solvent extraction on the clarified solution exiting the final solids-liquid separation, with washing, to try to recover any final amounts of valuable metal.
  • the metal-depleted aqueous solution exiting the final solvent extraction unit is neutralized, as necessary, and/or circulated to one or more additional units to possibly recover other metal values that may also be present in the original ore, prior to disposal and/or recycle back to the final solid-liquid separation, with washing, as wash solution.
  • the metal-depleted aqueous slurry of the leached solids exiting the final solids-liquid separation, with washing, is then sent to final disposal, which, in most cases, includes neutralization.
  • final disposal which, in most cases, includes neutralization.
  • raff ⁇ nates from each solvent extraction unit, except the final solvent extraction unit may be totally recycled to one or more of the preceding agitation leach unit(s), and, in doing so, much more leaching agent is recy- cled to leaching and, therefore, much less leaching agent is lost to final disposal as compared to the conventional and "split circuit" flow sheets.
  • the desired metal lost to final disposal in the leached and washed solids is minimized when compared to either the conventional or "split circuit" flow sheets.
  • the crushed and milled ore solids are subjected to a sequence of leach units, each leach unit dissolving a portion of the desired metal values from, effectively, the same crushed ore solids (the original crushed and milled ore solids in the first agitation leach unit and progressively-more-leached solids pulps in subsequent agitation leach units in the series) with each such leaching unit being followed by its own solids-liquid separation without significant dilution, then one or more solvent extraction units to extract the desired metal value from the aqueous leach solution, rich in desired metal values, coming from the respective solids-liquid separation unit(s).
  • all, or almost all, of the aqueous raff ⁇ nates regenerated by the solvent extractions are recycled back to either their respective leach units, or recycled among two or more of the previous or following leach units in the circuit, for additional leaching, prior to a final solids-liquid separation, with washing. That final separation is applied to the crushed and milled leached solids exiting the last solids-liquid separation without significant dilution, and is followed by a final solvent extraction on the clarified leach solution exiting the final solids-liquid separation.
  • any copper agitation leach-solvent extraction recovery process all the sulphuric acid recycled back to leaching may be used to leach more copper, while all the acid taken to neutralization or contained in the tailings is lost, and, therefore, cannot be used to leach more copper.
  • the more acid that can be recycled the less acid that needs to be pur- chased, and the less the amount of acid that must be neutralized and/or that would be lost to disposal.
  • copper recovery from leaching is set at a realistic 90% and copper recovery from solvent extraction is also assumed to be a realistic 90%, even though copper recovery in an agitation leaching process can be up to nearly 100% in some cases and copper recovery across a copper solvent extraction unit can be more than 90% in some cases.
  • the instant invention provides a process for recovering metal values from crushed and milled ore solids comprising desired metal values that may be commingled with one or more other metal values, which process comprises:
  • each leaching “unit” may consist of several agitated leaching tanks in parallel or in series
  • each solvent extraction “unit” may consist of a single stages or a multiple number of stages, either extraction only or extraction and stripping in a typical arrangement, such as solvent extraction units or stages in parallel or series. It is also possible that all of the solvent extraction units are actually just different stages in a single solvent extraction plant.
  • the solvent extraction process is highly flexible and the particular arrangement of solvent extraction units or stages for any given leach solution is done in order to optimize recovery of the desired metal and to optimize regeneration of the leaching agent for recycle.
  • each solids-liquid separation with or without dilution/washing, may be conducted in any manner capable of separating solids from liquids; the method of such separations is not critical.
  • solids may be separated from liquids by methods including, but not limited to, decantation and/or filtration.
  • counter-current decantation is preferred, but is not mandatory.
  • significant dilution refers to the addition of a measurable amount of water or other aqueous solution. Dilution of any of the clarified leach solutions prior to circulation of them to solvent extraction could cause a build-up of the volume of aqueous phase in one of the loops, and as such, would be undesirable and could decrease leaching agent recovery. Significant dilution of such aqueous leach solution is only used in the instant process in the final solids-liquid separation as part of the final solids- liquid separation wash process to try to recover the last vestiges of the desired metal values from the pulp prior to disposal of the me- tal-depleted ore solids.
  • solvent extractions in accordance with the processes of the present invention may also be carried out in any known manner, wherein aqueous leach solution is contacted with an organic phase containing an extraction reagent, specific to the desired metal.
  • these solvent extractions may be carried out using mixer- settler solvent extraction units, wherein the organic phase and the aqueous leach solution are vigorously intermixed in a mixer, and the resulting dispersion of organic and aqueous is then passed to a settler where the two phases settle, and from which there exits a clear organic phase and a clear aqueous phase.
  • the "further metal recovery processes" to which the organic phases, rich in the desired metal values, may be subjected might comprise additional metal extraction followed by washing with a solution designed to remove undesirable species prior to contacting the organic phase, rich in desired metal values, with a suitable stripping agent that breaks apart the desired metal-extraction reagent complex and allows passage of the desired metal into an aqueous phase containing the desired metal in a concentrated and purified state from which final metal recovery takes place by electro winning, or one or more other final metal recovery methods.
  • With certain metals is may also be possible to recover the desired metal directly from the organic phase, rich in desired metal values, even though this is not a common technique.
  • all solutions, phases, raffinates, and pulps may be conveyed within the circuits of the process by pipes or any other natural or man-made conduit.
  • the process according to the instant invention may be practiced in a new plant designed specifically for the instant invention, or it may be practiced in an existing plant by reconfiguring existing equipment, and pulp and solution flows, without necessarily adding a great deal of handling and/or process equipment.
  • a majority of the desired metal values in the mined ore is intended to be leached from the crushed and milled ore solids in an initial leach unit, at least a majority of the desired metal values remaining in the solids pulp from the solids-liquid separator following the initial leach unit is leached in the next leach unit, and, in embodiments of the instant process comprising more than two leach units, the number of such units being limited by the economics of diminishing returns, the desired metal values in the mined ore are leached in sequential leach units progressively from a majority in the initial leach unit in the total circuit, a majority of the metal values remaining being leached in the next leach unit, and so on, until the last reasonably-recoverable amount of the remaining desired metal values from the original crushed and milled ore solids are leached by the final leach unit in the process/circuit.
  • the instant process which comprises leaching with two leach units
  • 60 to 75% of the desired metal values in the original ore might be preferably leached in the first leach unit, and the remaining 25 to 40% of such desired metal values would then be leached in the second leach unit.
  • 45 to 55% of such desired metal values in the original ore might be preferably leached in the first leach unit
  • 25 to 35% of such desired metal values might be preferably leached in the second leach unit
  • the remaining 10-30% of such desired metal values might preferably be leached in the third leach unit.
  • This sequential leaching practice generally results in the concentration of desired metal in the first clarified aqueous leach solution being at least 30% greater than the concentration of the desired metal in the second clarified aqueous leach solution, preferably this difference is at least 50%, more preferably this difference is at least 70%, and still more preferably this difference is 100%.
  • one or more intermediate agitation tank leach units may be inserted after the first solid-liquid separation and before the final agitated tank leach unit in step (c), such intermediate agitated tank leach unit sending an aqueous leach pulp, resulting from an aqueous leach solution being distributed through an aqueous leach pulp coming from the first solids-liquid separation, to an intermediate solids-liquid separation, from which an intermediate aqueous leach pulp is sent to the final agitated tank leach unit, and an intermediate clarified aqueous leach solution is circulated to an intermediate solvent extraction, from which an intermediate aqueous raffinate up to all of which raffinate may be recycled/circulated back to the intermediate agitated tank leach unit as at least a part of the aqueous leach solution for such leach unit, which solution may be supplemented by fresh leaching agent, and an intermediate desired metal-rich organic phase, rich in desired metal values, is sent to further metal recovery processes.
  • one such additional sub-circuit may comprise a leach unit, labelled an “intermediate agitation leach unit", a solids-liquid separator labelled an “intermediate solids-liquid separation", following this agitation leach unit, and a solvent extraction following the intermediate solids-liquid separation, this solvent extraction labelled an "interme- diate solvent extraction”.
  • Such an intermediate agitation leach unit might be inserted after the first solids-liquid separation and before the final agitated tank leach unit in step (c) in the process described above, such intermediate agitation leach unit sending an aqueous leach pulp, resulting from an aqueous leach solution being distributed through an aqueous leach pulp coming from the first solids-liquid separation, to an intermediate solids-liquid separation, from which an intermediate aqueous leach pulp is sent to the next agitation leach unit, and an intermediate clarified aqueous leach solution is circulated to an intermediate solvent extraction, from which exits an intermediate aqueous raffinate, up to all of which raffinate may be recycled/circulated back to the intermediate leach unit, or an earlier or later agitation leach unit, as at least a part of the aqueous leach solution for such leach unit, which solution may be supplemented by fresh leaching agent, and an intermediate organic phase, rich in the desired metal as a desired metal-extraction reagent(
  • the process according to the instant invention may be used in any metal recovery operation which employs an aqueous agitation leaching operation, where the leaching agent is regenerated in the solvent extraction process, and essentially with any leaching agent that is water- miscible, capable of leaching the desired metal from the mined ore into the desired metal leaching solution.
  • leaching agents include, but are not limited to acids, including sulphuric acid, hydrochloric acid, nitric acid, organic acids, and combinations of two or more thereof, and basic substances, including gaseous ammonia and ammonium hydroxide.
  • the leaching agent is sulphuric acid, resulting in each aqueous leach solution, i.e., the first aqueous leach solution, the second aqueous leach solution, the third aqueous solution, any intermediate aqueous leach solution, and so on, as well as each raffinate, i.e., the first aqueous raffinate, the second aqueous raffi- nate, the third aqueous raffinate, and so on, being sulphuric acid solutions.
  • the preferred leaching agent is gaseous ammonia or ammonium hydroxide, resulting in each of the leach solutions, i.e., the first aqueous leach solution, the second aqueous leach solution, the third aqueous solution, any intermediate aqueous leach solution, and so on, as well as each raffinate, i.e., the first aqueous raffinate, the second aqueous raffinate, the third aqueous raffinate, and so on, being ammonia/ammonium hydroxide solutions.
  • the process of the invention is preferably used in the leaching and solvent extraction of desired metals that occur naturally as oxide and/or sulphide ores, preferably in the leaching and solvent extraction of divalent metals, such as copper, zinc, nickel and cobalt, and including, for example, transition metals.
  • the desired metal is copper, and, particularly, when the desired metal is copper, the preferred leaching agent is sulphuric acid.
  • the desired metal is copper, and the preferred leaching agent is gaseous ammonia or ammonium hydroxide.
  • the desired metal is zinc, and particularly, when the desired metal is zinc, the leaching agent is sulphuric acid or gaseous ammonia or ammonium hydroxide.
  • the desired metal is nickel, and, particularly, when the desired metal is nickel, the preferred leaching agent is sulphuric acid or gaseous ammonia or ammonium hydroxide.
  • the desired metal is cobalt and the preferred leaching agent is sulphuric acid.
  • the aqueous raffinate from each solvent extraction process is generally recycled back to the leach unit from which the clarified aqueous leach solution that was circulated to that vessel originated most recently in order to leach more desired metal from the crushed and milled ore solids or a subsequent leach pulp.
  • a portion of the first aqueous raffinate, a portion of the second aqueous raffinate, a portion of the third aqueous raffinate, a portion of any in- termediate aqueous rafflnate(s), or a mixture of two or more thereof may be circulated to any of the leach units and/or the third solids-liquid separator in the process according to the present invention if needed to maintain a water balance or to more efficiently distribute leaching agent.
  • the first aqueous raffinate produced in accordance with the processes of the present invention will generally have a leaching agent concentration which is greater than the concentration of leaching agent present in the second aqueous raffinate
  • the second aqueous raffinate produced in accordance with the processes of the present invention will generally have a leaching agent concentration which is greater than the concentration of leaching agent present in the third aqueous raffinate, and so on, with the aqueous raffinate from a solvent extraction component of any additional "intermediate" sub-circuit in accordance with the processes of the present invention generally having a leaching agent concentration which is greater than the concentration of leaching agent present in the aqueous raffinate from the solvent extraction vessel next following in the instant process.
  • the first aqueous raffinate will have a leaching agent concentration which is at least 10% greater than the concentration of leaching agent present in the second aqueous raffinate, while in increasingly more preferred embodiments of the present invention, the first aqueous raffinate will have a leaching agent concentration which is at least 20% greater, preferably at least 50% greater, more preferably at least 75% greater and most preferably 100% greater.
  • leaching agent concentration which is at least 20% greater, preferably at least 50% greater, more preferably at least 75% greater and most preferably 100% greater.
  • the concentration of leaching agent in any intermediate aqueous raffinate over the concentration of leaching agent is the aqueous raffinate from the next- following solvent extraction vessel in the present process are also similar to those between the first and second aqueous raffinates.
  • the aqueous stream for diluting the fourth aqueous leach pulp (step (g)) is normally the raffinate from the final solvent extraction process, optionally with neutralization or optionally following metal recovery of a second valuable metal value, but it may comprise fresh water introduced into the process and/or a portion of other aqueous process streams to maintain a water balance.
  • any of the aqueous raffinate(s) may be at least partly neutralized (e.g., to any pH up to about 8) with any basic substance (e.g., lime when the leaching agent is sulphuric acid) prior to its use for diluting the fourth aqueous leach pulp in the third solid-liquid separation.
  • any basic substance e.g., lime when the leaching agent is sulphuric acid
  • FIG. 1 is a flow diagram, containing pertinent components of the mass balance for the circuit, representing the flows in a standard conventional agitation leaching-solvent extraction flow sheet, wherein all of the aqueous leach solution is treated in the same manner.
  • FIG. 2 is a flow diagram, with pertinent mass balance values, representing a "Split Circuit" flow sheet, wherein an aqueous leach solution is divided into two portions- one portion without significant dilution and the other with water dilution- prior to being subjected to solvent extraction.
  • FIG. 3 is a flow diagram, with pertinent mass balance values, representing an embodiment of the "Sequential Circuit" flow sheet according to the present invention.
  • Optional units/operations are shown in dashed lines, with a cobalt recovery unit representing one or more units for recovering other metal values that may be present in sufficient quantities in the incoming ore.
  • Comparative Example A is based on Figure 1, which depicts a process flow diagram of a standard conventional copper agitation leaching and solvent extraction circuit, with pertinent mass balance numbers included for aqueous flows, copper concentrations and acid concentrations.
  • the leach pulp exiting the leach unit/train consisting of about 1224 cubic meters/hour of aqueous leach solution, comprising 9.92 g/1 of copper and 2.0 g/1 of sulphuric acid, and about 362.5 tonnes/hour of crushed and milled ore less the mass leached, is mixed/washed, in a counter-current decantation ("CCD”), with about 622 cubic meters/hour of recycled aqueous raffinate from the copper solvent extraction unit/train (“SXl").
  • CCD counter-current decantation
  • SXl recycled aqueous raffinate from the copper solvent extraction unit/train
  • the 622 cubic meters/hour of raffinate containing 0.80 g/1 Cu was assumed to be neutralized to contain 2 g/1 sulphuric acid before addition to the CCD circuit as wash solution, thus diluting the copper concentration of the aqueous leach solution exiting the CCD circuit from about 9.92 g/1 copper to about 8.05 g/1 copper prior to this solution being fed to the solvent extraction.
  • the about 622 cubic meters/hour of raffinate, which is recycled to the CCD operation, is used to wash the leach solution from the leached solids, in order to minimize soluble metal losses in the aqueous phase portion of the leached pulp that is eventually disposed to tailings.
  • a small portion of fresh water may be added to the overall leach/wash system or a small portion of aqueous solution may be bled from the overall leach/wash system to maintain a water balance.
  • Comparative Example A 913 cubic meters per hour of raffinate containing 13.2 g/1 sulphuric acid would be returned to leaching, about 622 cubic meters per hour of raffinate containing 13.2 g/1 sulphuric acid is neutralized to 2.0 g/1 sulphuric acid prior to recycle back to the CCD circuit, and about 311 cubic meters per hour of aqueous solution containing 0.91 g/1 copper is lost in tailings. Comparative Example B
  • Comparative Example B is based on Figure 2, which depicts a process flow diagram of a "Split Circuit" copper leaching and solvent extraction system, with pertinent mass balance numbers included for aqueous flows, copper concentrations and acid concentrations.
  • the leach pulp exiting the leach unit/train (“LEACH”) consisting of about 1224 cubic meters/hour of aqueous leach solution, comprising 9.92 g/1 of copper and 2.0 g/1 of sulphuric acid, and about 362.5 tonnes/hour of crushed and milled ore, less the mass leached, is passed to an initial solids-liquid separation (S/L), comprising a clarifier using decantation.
  • LEACH leach unit/train
  • the leach pulp exiting the initial solid-liquid separation which contains about 311 cubic me- ters/hour of leach solution, is taken to a counter-current decantation wash circuit (CCD) where it is mixed with about 622 cubic meters/hour of raffinate from SX 2 that has been, optionally, partially neutralized to 2.0 g/1 sulphuric acid.
  • CCD counter-current decantation wash circuit
  • About 622 cubic meters/hour of leach solution from the CCD circuit comprising 5.21 g/1 copper and 2.0 g/1 sulphuric acid, is taken to SX 2 to give a raffinate containing 0.52 g/1 copper and 9.2 g/1 sulphuric acid.
  • a small portion of fresh water may be added to the overall leach/wash system or a small portion of aqueous solution may be bled from the overall leach/wash system to maintain a water balance.
  • the amount of acid in any aqueous stream at a particular time is the stream flow at that time multiplied by the acid concentration in the stream.
  • a simple calculation shows that for this particular case about 2.51 more metric tons of acid/hour, or about 60.3 more metric tons of acid/day, is recycled to leaching using the "Split Circuit" flow sheet of Comparative Example B over the standard conventional flow sheet of Comparative Example A.
  • Acid costs vary widely from, currently, about US$60/ton to above US$250/ton depending on the location.
  • the amount of copper in any aqueous stream at a particular time is the stream flow at that time multiplied by the copper concentration in the stream.
  • a third simple calculation shows that the total copper recovered using the "Split Circuit" flow sheet of Comparative Example B is greater than the total copper recovered using the standard conventional flow sheet of Comparative Example A by 74.64 kilograms/hour or about 1.79 tonnes/day.
  • this additional copper has a value of US$9,866/day or about US$3.55M annually.
  • Example 1 illustrating the present invention is based on Figure 3, which depicts a process flow diagram of a simple example of a copper leaching and solvent extraction process according to the instant invention (denominated "Sequential Circuit"), with pertinent mass balance numbers included for aqueous flows, copper concentrations and acid concentrations.
  • a leach pulp consisting of about 1224 cubic meters/hour of aqueous leach solution, comprising 7.56 g/1 of copper and 2.0 g/1 of sulphuric acid, and about 362.5 tonnes/hour of crushed and milled ore less the mass leached, flows directly without dilution from this first leach unit (Leach 1), where about 75% of the copper from the crushed, mined ore has been dissolved into an aqueous acidic leach solution, to a solid-liquid separator (S/Ll).
  • Leach 1 first leach unit
  • S/Ll solid-liquid separator
  • S/Ll From sepa- rator S/Ll about 913 cubic meters/hour of an aqueous leach solution, comprising 7.56 g/1 copper and 2.0 g/1 sulphuric acid, is circulated to a solvent extraction unit/train (SXl), and a pulp, consisting of about 31 1 cubic meters/hour of leach solution and about 362.5 tonnes/hour of partially leached crushed and milled ore less the small mass of ore leached in Leach 1 , is sent to a second leach unit.
  • SXl solvent extraction unit/train
  • the remaining amount of copper in the partially leached crushed and milled ore solids exiting Leach 1 (25% of the original amount in the crushed and milled ore solids entering Leach 1) is then dissolved from the solids in LEACH 2, from which 1224 cubic meters/hour of aqueous leach solution, comprising 4.6g/l copper and 2.0 g/1 sulphuric acid, and about 362.5 ton- nes/hour of solids less the total mass leached, is sent to another solid-liquid separator (S/L2), again, without dilution.
  • S/L2 solid-liquid separator
  • a second aqueous leach solution comprising about 4.6 g/1 copper and 2.0 g/1 sulphuric acid emerges from S/L2 and is circulated to a second solvent extraction unit (SX2), and a pulp, consisting of about 331 cubic meters/hour of leach solution and about 362.5 tonnes/hour of almost totally leached solids less the mass leached, is sent to a third solid-liquid separator (CCD) where the pulp is diluted and washed
  • CCD solid-liquid separator
  • the entire 913 cubic meters/hour of metal-depleted aqueous leach solution, comprising 8.4 g/1 sulphuric acid and 0.46 g/1 copper, are recycled from SX2 to LEACH 2 where the acid contained in this second raffinate is used to leach copper from the partially leached crushed and milled ore solids entering Leach 2 from S/Ll .
  • Exiting the CCD wash process is a pulp, consisting of 311 cubic meters/hour of aqueous solution, comprising 0.31 g/1 copper and 2 g/1 sulphuric acid, and 362.5 tonnes/hour of almost totally leached solids, which is sent to tails and 622 cubic meters/hour of a third aqueous leach solution, comprising 2.4 g/1 copper and 2.0 g/1 sulphuric acid, which is sent to a final solvent extraction unit (SX3).
  • SX3 final solvent extraction unit
  • Example 1 In Example 1, about 913 cubic meters/hour of raffinate containing 12.5 g/1 acid and about 913 cubic meters/hour of raffinate containing 8.4 g/1 acid are returned to Leach 1 and 2, respectively. About 622 cubic meters/hour raffinate from SX 3 containing 5.3 g/1 acid is neutralized to 2 g/1 acid and about 311 cubic meters/hour of aqueous solution containing 0.31 g/1 copper is lost to tailings Example 3 Economic benefit calculation
  • the neutralization cost/year is calculated by multiplying the acid neutralized/day by the cost of neutralization times 360 days/year.
  • the cost of neutralization assumed to be US$ 200/tonne acid, is the total cost of the acid plus the cost of the base needed to neutralize the acid plus a small operating cost.
  • a neutralization cost of US$ 200 tonne acid is used for this example and such cost is reasonable for neutralization and well within the range of today's costs for neutralization.
  • the benefit of the acid savings on an annual basis for the Sequential Circuit flow sheet according to the instant invention over the Split Circuit flow sheet and over the conventional standard flow sheet is calculated from the difference in the neutralization cost for each of the three flow sheets. Also in Table 2, the benefit on an annual basis associated with the lower soluble copper loss offered by the by the Sequential Circuit flow sheet according to this instant invention over the "Split Circuit" flow sheet and over the conventional standard flow sheet is determined from the differences in the economic value of the soluble copper lost on an annual basis (the con- centration of the copper in the respective streams exiting the CCD wash circuit to Tails times the flow calculated on an annual basis times the copper price) for each of the three flow sheets.
  • the leaching process is divided into a first leach, where a majority of the copper is leached, and a sec- ond leach, where the remainder of the copper is leached, the copper concentration in the aqueous phase in contact with the almost-totally-leached, crushed and milled ore solids in the last leach unit is considerably lower (4.60 g/1 Cu) than when all the leaching is done in one leaching unit/train (10.07 g/1 Cu in the case of the split circuit flow sheet and 9.92 g/1 Cu in the case of the standard conventional flow sheet).
  • a lower copper concentration in the leach solution in contact with the final leached solids should allow a very slightly higher overall leach recovery because the diffusion of leached copper from the pores in the ore particles is faster.
  • the acid to leach can be better controlled and thus made more efficient.
  • a fifth benefit may occur in those cases where the acid in the stream being recycled to the CCD wash process does not need to be neutralized, but the bleed of this stream from which a component of value in the bleed is recovered, for example cobalt, must be neutralized prior to cobalt recovery.
  • Neutralization with a soluble base such as caustic or ammonia, is very expensive, thus the lower the acid content of the bleed stream, the lower the amount of expensive base needed for neutralization.
  • the use of a solution of caustic for neutrali- zation adds water to the bleed stream, thereby diluting the valuable cobalt stream.
  • neutralization can take place with lime or limestone, which is a less costly base.
  • a lesser amount of acid in the bleed stream requires less lime or limestone for neutralization, and in the process, a lesser amount of gypsum precipitate, that must be removed from the system, is produced.
  • a lesser amount of gypsum allows the use of smaller equipment for this particular solid-liquid separation. Since, when finely-divided solids separated from a liquid, the solids will always contain some of the liquid, a lesser amount of gypsum will contain a lower volume of the neutralized bleed stream that contains the valuable second component, for example, cobalt. Thus, the ultimate recovery of the secondary valuable component in the bleed stream is higher when using the process according to the invention.

Landscapes

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

Abstract

La présente invention concerne un procédé amélioré pour la récupération de métal à partir de minerai à l'aide d'une lixiviation par agitation, comprenant la division de la lixiviation du minerai broyé et exploité en au moins deux circuits secondaires d'extraction avec solvant pour une séparation solides/liquides de lixiviation, sans dilution significative lors de la séparation solides/liquides dans ces unités, et le raffinat provenant de l'extraction avec solvant étant recyclé vers la lixiviation. La pulpe de tamisat provenant du second séparateur solides/liquides est envoyée vers un séparateur solides/liquides final, avec lavage à l'eau, à partir duquel les solides lavés sont envoyés vers l'évacuation et la solution de lavage aqueuse clarifiée est envoyée vers une extraction avec solvant finale, une partie ou la totalité du raffinat aqueux appauvri en métal provenant de cette extraction avec solvant finale étant facultativement neutralisée et/ou étant mise à circuler pour repartir vers la troisième séparation solides/liquides sous forme de solution de lavage et/ou vers la récupération d'autres métaux et/ou vers l'évacuation afin de maximiser la récupération de métal et de conserver l'équilibre en eau.
PCT/EP2008/010979 2007-12-31 2008-12-20 Procédé amélioré pour la récupération de métal et recyclage d'agent de lixiviation dans des installations à lixiviation par agitation WO2009083204A1 (fr)

Priority Applications (6)

Application Number Priority Date Filing Date Title
CA2711025A CA2711025C (fr) 2007-12-31 2008-12-20 Procede ameliore pour la recuperation de metal et recyclage d'agent de lixiviation dans des installations a lixiviation par agitation
BRPI0821491-3A BRPI0821491A2 (pt) 2007-12-31 2008-12-20 Método aperfeiçoado para recuperação de metal e reciclagem de agente de lixiviação em instalações de lixiviação por agitação
US12/811,285 US20100282025A1 (en) 2007-12-31 2008-12-20 Method For Metal Recovery and Leaching Agent Recycle in Agitation Leach Plants
MX2010005024A MX2010005024A (es) 2007-12-31 2008-12-20 Metodo mejorado para recuperacion de metal y reciclaje de agente de lixiviacion en plantas de lixiviacion de agitacion.
AU2008342921A AU2008342921B2 (en) 2007-12-31 2008-12-20 Improved method for metal recovery and leaching agent recycle in agitation leach plants
ZA2010/04346A ZA201004346B (en) 2007-12-31 2010-06-21 Improved method for metal recovery and leaching agent recycle in agitation leach plants

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US971907P 2007-12-31 2007-12-31
US61/009,719 2007-12-31

Publications (1)

Publication Number Publication Date
WO2009083204A1 true WO2009083204A1 (fr) 2009-07-09

Family

ID=40377569

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2008/010979 WO2009083204A1 (fr) 2007-12-31 2008-12-20 Procédé amélioré pour la récupération de métal et recyclage d'agent de lixiviation dans des installations à lixiviation par agitation

Country Status (9)

Country Link
US (1) US20100282025A1 (fr)
AU (1) AU2008342921B2 (fr)
BR (1) BRPI0821491A2 (fr)
CA (1) CA2711025C (fr)
CL (1) CL2008003922A1 (fr)
MX (1) MX2010005024A (fr)
PE (1) PE20091512A1 (fr)
WO (1) WO2009083204A1 (fr)
ZA (1) ZA201004346B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104445410A (zh) * 2014-11-14 2015-03-25 金堆城钼业股份有限公司 一种钼焙砂的水洗方法

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2014328397B2 (en) * 2013-09-27 2018-10-18 Sepro Mineral Systems Corp. Method and apparatus for liquid/solid separation such as dewatering particulate solids and agitation leaching
US10030286B1 (en) 2013-11-13 2018-07-24 Ii-Vi Incorporated Method of direct solvent extraction of rare earth metals from an aqueous acid-leached ore slurry
BR112017020592B1 (pt) 2015-04-08 2021-09-21 Ecolab Usa Inc. Métodos para extrair metal de um minério portador de metal e para melhorar a eficiência de lixiviação em um processo de extração de metal, pasta aquosa, e, uso de uma composição de tensoativo e um agente de lixiviação
CN109874342A (zh) 2015-10-30 2019-06-11 Ii－Vi 有限公司 复合萃取剂增强的聚合物树脂、其制备方法及其萃取（一种或多种）贵重金属的用途
US10808296B2 (en) 2015-10-30 2020-10-20 Ii-Vi Delaware, Inc. Selective recovery of rare earth metals from an acidic slurry or acidic solution

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050031512A1 (en) * 2003-07-30 2005-02-10 Kordosky Gary A. Methods for improving the recovery of metal leaching agents
US20060228279A1 (en) * 2005-04-07 2006-10-12 Finlay Campbell Process for recovery of nickel and cobalt from laterite ore
US7169371B2 (en) * 2001-12-03 2007-01-30 Cominco Engineering Services Ltd. Process for the treatment of molybdenum concentrate

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3950487A (en) * 1974-06-13 1976-04-13 Kennecott Copper Corporation Solvent-in-pulp extraction of copper and nickel from ammoniacal leach slurries
US4093526A (en) * 1977-09-08 1978-06-06 Amax Inc. Hydrometallurgical leaching and refining of nickel-copper concentrates, and electrowinning of copper
US7635457B2 (en) * 2004-10-04 2009-12-22 Cognis Ip Management Gmbh Method for heap and dump leaching coupled with solvent extraction for metal recovery
FI118302B (fi) * 2006-02-17 2007-09-28 Outotec Oyj Menetelmä kullan talteenottamiseksi

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7169371B2 (en) * 2001-12-03 2007-01-30 Cominco Engineering Services Ltd. Process for the treatment of molybdenum concentrate
US20050031512A1 (en) * 2003-07-30 2005-02-10 Kordosky Gary A. Methods for improving the recovery of metal leaching agents
US20060228279A1 (en) * 2005-04-07 2006-10-12 Finlay Campbell Process for recovery of nickel and cobalt from laterite ore

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104445410A (zh) * 2014-11-14 2015-03-25 金堆城钼业股份有限公司 一种钼焙砂的水洗方法

Also Published As

Publication number Publication date
AU2008342921A1 (en) 2009-07-09
CA2711025C (fr) 2017-03-28
US20100282025A1 (en) 2010-11-11
ZA201004346B (en) 2011-03-30
CA2711025A1 (fr) 2009-07-09
MX2010005024A (es) 2010-07-02
CL2008003922A1 (es) 2010-01-22
BRPI0821491A2 (pt) 2015-06-16
PE20091512A1 (es) 2009-11-01
AU2008342921B2 (en) 2013-03-21

Similar Documents

Publication Publication Date Title
US8062614B2 (en) Methods for improving the recovery of metal leaching agents
EP2201145B1 (fr) Circuit de récupération de cuivre par lixiviation contrôlée
US10793958B2 (en) System and method for parallel solution extraction of one or more metal values from metal-bearing materials
CA2711025C (fr) Procede ameliore pour la recuperation de metal et recyclage d'agent de lixiviation dans des installations a lixiviation par agitation
US20180305788A1 (en) System and method including multi-circuit solution extraction for recovery of metal values from metal-bearing materials
AU2005294588B2 (en) Improved method for metal heap and dump leaching coupled with metal solvent extraction
Cole et al. Solvent extraction developments in Southern Africa
US7214256B2 (en) Solvent extraction process
US5758255A (en) Opposite phase entrainment reduction in solvent extraction/electrowinning circuits by addition of water soluble cationic polymers
Nisbett et al. Flowsheet considerations for copper cobalt projects
US4032330A (en) Process for recovery of copper
WO2016081976A1 (fr) Procédé pour l'amélioration de la récupération d'uranium et de métaux de base à partir de liqueur enrichie de lixiviation en tas
MXPA06000863A (en) Methods for improving the recovery of metal leaching agents
AU5401801A (en) Processing gold containing copper sulphide feeds

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: 08866695

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: MX/A/2010/005024

Country of ref document: MX

WWE Wipo information: entry into national phase

Ref document number: 2008342921

Country of ref document: AU

Ref document number: 2711025

Country of ref document: CA

WWE Wipo information: entry into national phase

Ref document number: 12811285

Country of ref document: US

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2008342921

Country of ref document: AU

Date of ref document: 20081220

Kind code of ref document: A

122 Ep: pct application non-entry in european phase

Ref document number: 08866695

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: PI0821491

Country of ref document: BR

Kind code of ref document: A2

Effective date: 20100628