WO2011156861A1 - Procédé de récupération d'un métal - Google Patents

Procédé de récupération d'un métal Download PDF

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Publication number
WO2011156861A1
WO2011156861A1 PCT/AU2011/000726 AU2011000726W WO2011156861A1 WO 2011156861 A1 WO2011156861 A1 WO 2011156861A1 AU 2011000726 W AU2011000726 W AU 2011000726W WO 2011156861 A1 WO2011156861 A1 WO 2011156861A1
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WIPO (PCT)
Prior art keywords
metal
leach solution
halide
solution
source material
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Application number
PCT/AU2011/000726
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English (en)
Inventor
James Vaughan
Original Assignee
The University Of Queensland
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.)
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Publication date
Priority claimed from AU2010902602A external-priority patent/AU2010902602A0/en
Application filed by The University Of Queensland filed Critical The University Of Queensland
Publication of WO2011156861A1 publication Critical patent/WO2011156861A1/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
    • C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
    • C22B3/06—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions
    • C22B3/10—Hydrochloric acid, other halogenated acids or salts thereof
    • 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
    • C22B11/00—Obtaining noble metals
    • C22B11/04—Obtaining noble metals by wet processes
    • 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
    • C22B11/00—Obtaining noble metals
    • C22B11/04—Obtaining noble metals by wet processes
    • C22B11/042—Recovery of noble metals from waste materials
    • C22B11/048—Recovery of noble metals from waste materials from spent catalysts
    • 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
    • C22B11/00—Obtaining noble metals
    • C22B11/06—Chloridising
    • 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
    • C22B3/44—Treatment or purification of solutions, e.g. obtained by leaching by chemical processes
    • C22B3/46—Treatment or purification of solutions, e.g. obtained by leaching by chemical processes by substitution, e.g. by cementation
    • 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 a method of recovering a metal from a source material. More particularly, the present invention relates to a method of recovering a metal from impure sources such as automobile catalytic converters, ores or waste materials.
  • Platinum, palladium and rhodium are valuable commodities which have found use in a wide range of applications.
  • platinum, palladium and rhodium are used extensively in the production of automobile catalytic converters, otherwise known as autocatalysts.
  • Catalytic converters are employed on vehicles to reduce their emission of hydrocarbons, carbon monoxide and other noxious substances.
  • the catalytic properties of platinum group metals are harnessed to convert these emissions into relatively harmless substances such as carbon dioxide, nitrogen and water vapour.
  • Prior art methods typically employ high pressure autoclave conditions and/or high temperatures during the leaching process. Many also require very high acid concentrations which not only raises safety concerns but also results in high operation costs due to constant consumption of the acid by reaction with the ceramic substrate and like components.
  • One method which avoids high acid concentrations requires the use of cyanide salts which can be undesirable from a safety perspective as hydrogen cyanide production is a possibility.
  • the present inventor has identified a need for a method of recovering platinum group metals from automobile catalytic converters which can be performed at relatively low temperatures and ambient pressure. It would further be desirable to reduce the need for large quantities of acid and otherwise aid in improving the safety profile and process economics of such a method. It would be useful if the method could also be applied to the recovery of one or more non-platinum group metals.
  • the object of the invention is to overcome or at least alleviate one or more of the above problems or to at least provide for a useful commercial choice.
  • the invention resides in a method of recovering a metal from a source material by leaching the metal into a leach solution containing high concentrations of a metal halide as a halide ion donor to solubilise the metal.
  • the invention resides in a method of recovering a metal from a source material including the steps of:
  • the .concentration of halide ions donated to the leach solution by the metal halide may be at least 8 moles/Litre.
  • the concentration of halide ions donated to the leach solution by the metal halide may be at least 9 moles/Litre. More preferably, the concentration of the metal halide in the leach solution is about 10 moles/Litre.
  • the metal halide donates about 500 to about 5000 molar equivalents of halide ion to extracted metal present in the metal- containing leach solution.
  • the metal halide donates about 1000 to about 3000 molar equivalents, more preferably about 2000 molar equivalents.
  • the method further includes the step of adding an oxidant and/or an acid to the leach solution.
  • the leach solution may have a high ratio of halide ions donated by the metal halide to hydrogen ions/protons donated by the acid.
  • the molar ratio of halide ions to hydrogen ions/protons in the leach solution is at least 2:1.
  • the molar ratio of halide ions to hydrogen ions/protons in the leach solution is at least 5:1.
  • the molar ratio of halide ions to hydrogen ions/protons in the leach solution is at least 10:1.
  • the acid is present at a concentration of between about 0.001 to about 1.0 moles-proton/L.
  • the majority of the halide ions present in the leach solution are donated by the metal halide.
  • greater than 90% of the halide ions present in the leach solution are donated by the metal halide.
  • the leach solution is recycled for use in recovery of further metal from the same or a different source material.
  • the recycled leach solution comprises a substantially similar concentration of metal halide to the leach solution prior to contact with the source material. If required, the leach solution may be recycled indefinitely.
  • the leach solution may be recycled before or after recovery of the metal.
  • the majority of the metal to be recovered from the source material is leached into the leach solution.
  • the metal is a metal capable of forming a soluble halide complex.
  • the metal is a noble metal.
  • the metal being recovered may be selected from the group consisting of rhenium, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, and gold.
  • the metal being recovered is selected from the group consisting of rhodium, palladium, platinum, silver and gold.
  • the source material may be an automobile catalytic converter or part thereof, an ore or waste material comprising the metal.
  • the metal is a platinum group metal (PGM) metal.
  • the PGM is selected from the group consisting of platinum, palladium and rhodium.
  • cerium may be recovered from the source material in addition to the noble metal.
  • the metal recovered is preferably gold, silver or palladium.
  • the metal halide is an alkali metal halide or alkaline earth metal halide or combination thereof.
  • the metal halide is selected from the group consisting of a magnesium, calcium and sodium halide salt.
  • the metal halide is magnesium chloride or calcium chloride.
  • the reducing agent may be a metal and/or hydrogen gas.
  • the method may further include the step of comminuting the source material prior to contact with the leach solution.
  • the source material is calcined at an elevated temperature prior to treatment with the leach solution.
  • the leach solution may be maintained at or below 120°C, preferably at or below 100°C during contact with the source material.
  • the leach solution may be at ambient pressure upon contacting the source material.
  • the method does not involve the use of cyanide salts in the leach solution or the reducing step.
  • the method may further include the step of subjecting the source material .to a magnetic separation step prior to treatment with the leach solution.
  • the method may further include the step of contacting the metal- containing leach solution with a precipitation agent to precipitate metallic impurities prior to treatment with the reducing agent.
  • the precipitation agent is a metal oxide such as magnesium oxide.
  • FIG 1 is a flow sheet describing steps involved in recovering a noble metal from an automobile catalytic converter, according to one embodiment of the invention
  • FIG 2 is a representation of the effect of pulverising an automobile catalyst on the subsequent leaching of various metals
  • FIG 3 is a graphical representation of the effect of different oxidants on the recovery of platinum
  • FIG 4 is a graphical representation of the effect of varying the concentration of MgC in the leach solution on the recovery of platinum;
  • FIG 5 is a graphical representation of the effect of varying oxidant and acid concentrations on the recovery of platinum
  • FIG 6 is a graphical representation of the recovery of platinum, palladium and rhodium from an automobile catalytic converter sample
  • FIG 7 is a graphical representation of the recovery of non-noble metals from the used leach solution
  • FIG 8 is a graphical representation of the effect of including ferric chloride as an additional oxidant in the leach solution
  • FIG 9 is a graphical representation of the effect of sequential leaching of fresh catalyst samples using a recycled leach solution on the recovery to solution of platinum, palladium and rhodium;
  • FIG 10 is a graphical representation of the effect of sequential leaching of fresh catalyst samples using a recycled leach solution on the recovery to solution of cerium, lead, silicon and iron;
  • FIG 11 is a graphical representation of the extraction of palladium, platinum and rhodium in an initial leach, re-leach, and aqua regia digestion
  • FIG 12 is a graphical representation of the removal of impurities from the leach solution by precipitation
  • FIG 13 is a graphical representation of the effect of varying reducing conditions on the recovery of platinum from the leach solution
  • FIG 14 is a graphical representation of the effect of acid on the recovery of platinum from solution
  • FIG 15 is a graphical representation of the recovery of platinum group metals from solution.
  • FIG 16 is a graphical representation of the extraction of gold and silver from an impure source material into a leaching solution.
  • the present invention is predicated, at least in part, on the development of a method of recovering valuable metals such as platinum, palladium and rhodium from automobile catalytic converters using a leach solution having a high concentration of a metal halide, such as magnesium chloride.
  • the method further extends to the recovery of other valuable metals, including silver and gold, from ores, waste materials or other impure sources.
  • the leaching process further employs an oxidant and, advantageously, requires relatively low acid concentrations.
  • the present method has the further advantage that the used leach solution, following removal of the extracted noble metal, lends itself to recycling thereby greatly reducing reagent and solution preparation costs.
  • the method described provides for a safer, simpler and more cost effective method of recovering these valuable resources.
  • the method of recovering the metals is generally described in relation to automobile catalytic converters only. However, it will be appreciated that it is possible, using the same or a substantially similar process, to recover the same or similar metals from a wide variety of impure sources.
  • non-noble metaf and “noble metals”, as used herein, may refer to any one or more of a number of metallic elements which can form soluble halide complexes and may include rhenium, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, and gold.
  • the method of the invention is particularly suited to the recovery of platinum, palladium, rhodium, silver and gold.
  • platinum group metaf platinum, palladium, rhodium, ruthenium, osmium and iridium.
  • source materia!' may refer to any impure source of a noble metal including natural sources such as ores and man- made sources such as automobile catalytic converters, electronic waste or components thereof.
  • FIG 1 is a flow sheet describing steps involved in recovering a noble metal from an automobile catalytic converter, according to one embodiment of the invention.
  • the skilled addressee will appreciate that not every step shown is essential to the recovery of the noble metals.
  • the various parts of the process will now be described.
  • the automobile catalyst is first separated from its steel shell to isolate the generally honeycomb ceramic support structure. This component, which contains the noble catalytic metals, is then crushed and/or ground to reduce its particle size to increase the surface area upon which the subsequently used reagents may act.
  • the automobile catalyst may be ground down to an average particle size of less than 10 mm, preferably less then 6mm.
  • the automobile catalyst may be further pulverised to as great an extent as is practicable, for example, such that all material can pass through a 212 pm sieve. This provides an optimal surface area while avoiding any noticeable reduction in the rate of subsequent solid-liquid separation.
  • FIG 2 is a representation of the effect of pulverising an automobile catalyst on the subsequent leaching of various metals wherein, on the Y axis, the units for aluminium are g / kg catalyst; for iron, lead, silicon and cerium they are g / 10kg catalyst; and for palladium, platinum and rhodium they are g / 100kg catalyst.
  • the autocatalyst was pulverised such that 100% of materials passed through a 212 pm sieve.
  • the conditions for the leaching experiment represented in FIG 2 are a 5 M MgCI 2 aqueous solution with 0.17 g of Na 2 S 2 0 8 /g of catalyst, 0.09 g of HCI /g of catalyst with exposure for 6 h at 80°C with approximately 4.8 % solids. It is clear from FIG 2 that reducing the particle size of the source material provides for an improvement in the ability to leach noble metals such as the PGMs.
  • any magnetic, for example iron-containing, impurities may be removed during or after the particle size reduction step by way of a magnetic separation step.
  • the comminuted automobile catalyst may then be calcined by heating the dry material in the presence of air, preferably under a forced convection.
  • the calcination temperature may be between about 200°C to about 1000°C, preferably about 300°C to about 700°C and more preferably about 500°C.
  • a person of skill in the art will easily be able to determine a suitable temperature based on the knowledge that the temperature and air flow must be sufficient to oxidise carbonaceous material and oil that is found within the used automobile catalyst. Although this step may not be essential it is a preferred approach as the carbonaceous material and oil can interfere with the subsequent leaching stage by consuming reagents and/or adsorbing the noble metals thereby lowering recovery.
  • the calcined catalyst material is then treated with a leaching solution which contains a relatively high concentration of a metal halide which, in the embodiment shown in FIG 1 , is magnesium chloride (MgCI 2 ), along with an oxidant and an acid.
  • a metal halide which, in the embodiment shown in FIG 1 , is magnesium chloride (MgCI 2 ), along with an oxidant and an acid.
  • the magnesium chloride acts as a chloride ion source enabling the noble metals to form water soluble chloro complexes thereby resulting in their dissolution and leaching into the aqueous leaching solution.
  • the preferred concentration of the halide ions donated by the metal halide in the leach solution in the embodiments described will be about 10 moles/Litre although it will be appreciated that lower concentrations will still provide for at least partial recovery of the target noble metal.
  • the concentration of the halide ions donated by the metal halide in the leach solution may vary depending on the particular metal halide used.
  • the concentration of the halide ions donated by the metal halide in the leach solution will be between about 4 to about 14 moles/Litre, preferably about 6 to about 12 moles/Litre. Even more preferably, the concentration of the halide ions donated by the metal halide in the leach solution is about 0 moles/Litre. Between about 4 to about 14 moles/Litre includes 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13 and 14 moles/Litre.
  • the metal halide donates between about 500 to about 5000 molar equivalents of halide ion to extracted metal present in the metal-containing leach solution. This range is inclusive of about 500, 750, 1000, 1250, 1500, 1750, 2000, 2250, 2500, 2750, 3000, 3250, 3500, 3750, 4000, 4250, 4500, 4750 and 5000 molar equivalents of halide ion to extracted metal present in the metal-containing leach solution.
  • the metal halide donates about 1000 to about 3000 molar equivalents, more preferably about 2000 molar equivalents.
  • the metal halide is an alkali metal halide or alkaline earth metal halide or combination thereof.
  • the metal halide is selected from the group consisting of a magnesium halide, a calcium halide and a sodium halide.
  • Preferred metal halides salts are metal chlorides or bromides.
  • the metal halide is a metal chloride.
  • the metal halide is magnesium chloride or calcium chloride.
  • Rh + 6CI ' RhCle "3 + 3e " (3)
  • the conditions are such that the reactions proceed from left to right i.e. the metals are oxidised and form water soluble chloro complexes. This is achieved by the introduction of the oxidant and relatively small quantities of an acid such as hydrochloric acid (HCI), as shown in FIG 1, Any relatively strong mineral acid may be suitable.
  • HCI hydrochloric acid
  • An important advantage of the present method is that the metal halide employed as a halide source to form the noble metal soluble halide complexes does not, to any great extent, react with the ceramic support and other components and so is not consumed in the manner described. This enables the leaching solution to effectively be recycled indefinitely which greatly reduces process costs and provides for a more convenient iterative process. This effect has not been seen in the prior art.
  • the acid is present in the leach solution at a concentration less than or equal to 1.0 moles-proton/L.
  • the acid is present in the leach solution at a concentration of between about 0.001 to about 1.0 moles-proton/L inclusive of 0.001 , 0.005, 0.01 , 0.05, 0.1 , 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9-and 1.0 moles-proton/L.
  • Another way of describing the relatively low acid requirement in the present method is to look at the ratio of halide ions to hydrogen ions/protons in the leach solution.
  • the halide ions are mostly donated to the leach solution by the metal halide and the hydrogen ions/protons are the H + ion obtained in the leach solution upon the dissociation of acid e.g. when HCI dissociates into the H + and CI " ions. Since many prior art,methods rely on strong acid as their source of halide ions they have a ratio of halide ions to hydrogen ions/protons that is close to 1 :1.
  • the present invention employs high concentrations of the metal halide in the leach solution as the primary halide ion donor and so the molar ratio of halide ions to hydrogen ions/protons is considerably higher.
  • the molar ratio of halide ions to hydrogen ions/protons in the leach solution is at least 2:1 , preferably at least 5:1 , more preferably at least 10:1 , even more preferably at least 50:1 , more preferably still at least 100:1 and more preferably yet at least 200:1.
  • the chloride ion concentration of the leach solution is about 10 mole/L while the hydrogen ions/proton concentration is about 0.03 mole/L. This provides for a molar ratio of halide ions to hydrogen ions/protons of greater than 300: 1.
  • oxidants which would be known to the skilled addressee may be suitable for use in the present method including, but not limited to, calcium hypochlorite Ca(OCI)2, hydrogen peroxide (H 2 O 2 ), sodium persulfate (Na 2 S 2 08), ferric (Fe 3+ ) ions or magnesium peroxide (MgC>2).
  • Oxidising gases such as air, oxygen enriched air, oxygen and chlorine gas may also be suitable as alternative oxidants or may be used in combination with those already mentioned.
  • the next step shown in FIG 1 is the solid-liquid separation.
  • substantially all of the noble metals should be in the form of solubilised chloro complexes as indicated in equations (1) to (3).
  • This solution is isolated from the entrained solids by filtration, preferably under vacuum or positive pressure.
  • the solids may be washed with water or dilute acid to remove any leaching solution in contact with the solids.
  • the leaching solution containing the metal complexes must then be treated to recover the solid metals from solution.
  • Process conditions are altered to enable the equations shown above to proceed from right to left i.e. reducing conditions.
  • a reducing agent is added to the metal- containing leach solution.
  • Suitable reducing agents would be known to the skilled addressee.
  • Particularly preferred reducing agents for use in the present invention are metals such as iron or magnesium as they are more reactive than platinum and palladium although fluids such as hydrogen gas may also be useful and, indeed, hydrogen gas may be generated upon addition of the metal to the acidic noble metal-containing leach solution.
  • magnesium chloride is used as the metal halide in the leach solution then, advantageously, the use of magnesium as a reducing agent does not result in any contamination of the system and further improves the ability to repeatedly recycle the leach solution.
  • reducing agent to noble metal are added to achieve recovery, preferably about 30 equivalents. This includes about, 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 stoichiometric equivalents of reducing agent.
  • the precipitated solid metal is filtered off, washed and collected.
  • the solution from which the metals have been recovered may now be recycled straight away, unless further cycles of reduction are required, to the leaching step i.e. added to a fresh catalyst sample or, if required, a portion of the solution may first be bled off and treated to remove any impurities, such as iron, aluminium and other metal salts before being fed back to the leaching step.
  • the entire solution from which the metal has been recovered may be treated in one batch to remove these impurities before being employed in the next leaching step.
  • the treatment may be a simple matter of contacting the solution with magnesia and an oxidant to precipitate dissolved iron and aluminium as their hydroxides.
  • treatment of the recycled leaching solution may not be necessary. This is particularly so if the same metal reducing agent is used in the reduction step as forms the metal halide in the leaching step. In this case, treatment of the recycled leach solution may be unnecessary or may be required only periodically.
  • the pH of a solution only provides a relative indication of acidity and the skilled addressee will appreciate that the activity of the proton is a crucial consideration.
  • the activity is considerably higher than the actual concentration for both the proton and the chloride ion, this provides the strong driving force for the leaching reactions.
  • the activities are roughly on the order of 0 to 100 times the actual concentrations.
  • FIG 3 is a graphical representation of the effect of different oxidants on the recovery of platinum and represents the results of experiments 1 to 3.
  • Three different oxidants, sodium persulfate, hydrogen peroxide and calcium hypochlorite were evaluated in conditions of 13% solids, 80°C, 5M MgCI 2 in the leach solution and low acid concentration.
  • Table 2 Summary of results from leaching experiments of table 1
  • this low acid concentration provides benefits in that only a small amount of a precipitation agent such as magnesium oxide (MgO) or a like metal oxide is required to neutralise the acid whereas if a concentrated acid solution is employed it could not be efficiently recycled since it would be difficult or at least prohibitively expensive to neutralise all of the acid before purifying the solution. This is a considerable advantage when compared with prior art processes.
  • a precipitation agent such as magnesium oxide (MgO) or a like metal oxide
  • FIG 3 shows that the leaching process using pool chlorine (containing calcium hypochlorite) is slower than that seen with hydrogen peroxide and sodium persulfate.
  • Pool chlorine also consumes more acid as it contains calcium hydroxide.
  • the rate of dissolution of platinum using hydrogen peroxide was very high but a small amount of the dissolved platinum is eventually lost back to the solid phase as is seen by the downward slope in the graph as time progresses.
  • small gas bubbles are immediately formed (most likely a combination of oxygen and chlorine).
  • Some of the oxidant gas thereby created is apparently bubbling out of the reactor and is lost to the atmosphere.
  • solid sodium persulfate is seen to perform well with no noticeable gas formation and the amount of platinum in solution does not drop off with time as was observed with the peroxide.
  • FIG 4 is a graphical representation of the effect of varying the concentration of MgC ⁇ in the leach solution on the recovery of platinum and represents experiment 4, as shown in table 1.
  • the metal halide in this case magnesium chloride, is the primary source of halide ions to solubilise the target metals rather than necessitating high acid concentrations such as a HCI/HNO3 mixture (aqua regia).
  • Experiment 10 was designed to assess the value in performing a second cycle of leaching on the left over solid residue source material collected after the filtration step in experiment 3, subsequent to the initial leaching step. Leaching of the residue from experiment 3 resulted in the recovery of an extra 101 mg-Pt/kg-catalyst from the already 321 mg-Pt/kg catalyst for a total of 422 mg-Pt/kg catalyst.
  • the leaching step may be an at least two-stage counter current process to maximize recovery from the source material and optimise reagent usage. Further stages, such as a third, fourth, fifth stage etc may be employed if further amounts of the metal are recovered although it is expected that the majority of the metal will be recovered in the initial and/or re-leach processes.
  • FIG 5 is a graphical representation of the effect of varying oxidant and acid concentrations on the recovery of platinum and represents the results of experiment 12.
  • the traces indicate that the addition of further acid can actually lower the recovery of platinum unless it is in combination with additional oxidant.
  • the additional acid may liberate more platinum for potential recovery by dissolving the surrounding catalyst alumina substrate.
  • the acid may also dissolve other metallic impurities such as iron and these will consume the oxidant thereby leaving insufficient quantities for optimal platinum recovery. Therefore, the best result is obtained when excess oxidant is employed in combination with the additional acid.
  • FIG 6 is a graphical representation of the recovery of platinum, palladium and rhodium from an automobile catalytic converter sample as ' achieved in experiment 12 of table 1 using 13% solids, 80°C, 5M MgCI 2 leach solution, 15 g- a2S 2 0 8 , 4 g-H 2 0 2 and 19 g-HCI per kg catalyst. It can be seen that palladium recovery follows the same trend as is seen for platinum.
  • FIG 7 is a graphical representation of the recovery of non-noble metals from the used leach solution from experiment 12, as described above. This indicates that iron is by far the most common impurity. Since new catalysts should not contain iron it is believed that this is a result of contamination from the catalyst casing during separation. As previously mentioned, it may be preferable, for this reason, to remove these impurities by magnetic separation prior to leaching to reduce the unwanted consumption of acid and oxidant.
  • FIG 7 also shows that cerium is obtained in the leach solution. Cerium is a valuable commodity itself and so recovery of this metal in addition to those already discussed would further improve the economics of the process.
  • FIG 9 shows the recovery to solution of palladium, platinum and rhodium while FIG 10 shows the recovery of cerium, lead, silicon and iron with cerium being of some economic interest.
  • the leaching solution was diluted slightly for each sequential experiment which accounts for the temporary dips in concentration of the metals at approximately 180, 360 and 540 minutes.
  • FIG 9 clearly shows that even when employing a recycled leach solution already containing significant amounts of the PGMs, rhodium, palladium and, particularly, platinum continue to be leached into solution when contacted with fresh autocatalyst material. This confirms the viability of recycling the leach solution to minimise reagent usage and improve process economics.
  • FIG ' 10 shows that cerium can also continue to be leached into a solution which has undergone a number of cycles of usage.
  • FIG 1 1 is a graphical representation of the extraction of palladium, platinum and rhodium in an initial leach, as performed in the first set of tests set out in table 3, a re-leach, as performed according to the conditions in table 4, and an aqua regia digestion.
  • FIG 1 1 clearly indicates that, in most cases, the majority of the leaching of the noble metals takes place in the re- leach which confirms that a counter current leaching process, or other leach solution recycling system, would be highly effective in extracting these metals from a source material.
  • FIG 12 demonstrates that all of the major potential impurity metals, other than lead, can be precipitated out of solution as the metal hydroxide by the addition of MgO without precipitation of the PGMs to be recovered.
  • Any precipitation agent capable of causing the metallic impurities to form their hydroxide salts may be suitable.
  • the majority of all impurity metals have been removed with only cerium, which has had its concentration greatly reduced, and lead at noticeable levels.
  • the lead may be precipitated out to at least an extent as its sulphate or may be removed . via anion exchange techniques.
  • FIG 13 is a graphical representation of the effect of varying reducing conditions on the recovery of platinum from the leach solution.
  • the noble metals in the leach solution can be recovered to the solid state by electrochemical reduction (the opposite of the oxidation that took place in the leaching stage).
  • Certain metal powders are suitable reducing agents, such as iron and magnesium. Fluids such as hydrogen gas may also be useful. Iron and magnesium were selected for these tests as they are relatively inexpensive and, additionally, magnesium will not contaminate the system, as discussed earlier.
  • FIG 14 indicates that acid is necessary for the efficient recovery of platinum from solution.
  • the reducing conditions may employ a metal which will produce ⁇ hydrogen gas, as the reducing agent, upon reaction with the acid, or hydrogen gas may be directly bubbled into the reducing solution or introduced into a sealed vessel containing the leach solution with the hydrogen gas applied as an overpressure.
  • FIG 15 demonstrates that substantially all platinum, palladium and rhodium in solution can be recovered by electrochemical reduction within a 90 minute time period.
  • the purity of the solid PGM concentrate recovered from solution was quite high (greater than 50% PGM by mass) and may be improved by further simple dilute sulphuric acid leaching.
  • the results of the leaching experiments described above indicate that the highest recovery is achieved with additional oxidant, possibly ferric ions, relatively small amounts of acid and high magnesium chloride concentrations.
  • a leaching time of 3 to 4 hours was sufficient in all cases to enable a high level of extraction at the conditions tested.
  • the recovery of the target metals may be further improved by increased leaching time or, preferably, employing a two-stage counter current leaching process, or other leaching solution recycling process, which also maximises reagent efficiency.
  • Significant amounts of palladium, rhodium and, particularly, platinum are seen to be leached into solution.
  • the leach solution is favourably selective for the metals of interest as less than 4% of the total mass of the catalyst is actually dissolved and a build up of impurities in the recycled leach solution can be successfully addressed.
  • the recovery of the metals from solution has been shown to be extremely efficient.
  • gold and silver are known to form water soluble complexes with halide ions such as chloride ions.
  • Gold will generally form chloro complexes in either its Au(l) or Au(lll) oxidation states.
  • the gold metal can be recovered from a leach solution by reduction, as previously described.
  • Gold and silver are known to be dissolved by aqua regia but the present method provides a way to form the necessary soluble halide complexes under low acid concentrations providing a range of benefits already discussed.
  • a person of skill in the art would understand that different gold or silver-containing source materials may require different processing steps before being treated with the leach solution of the present invention. For example, electronic waste such as printed circuit boards may need to be deconstructed to remove various components that will consume reagents, particularly the acid, or will result in undesirable impurities being released into the leach solution.
  • the leach solution typically contained 5 Moles/L MgCI 2 and 2mL 32wt% HCI/L.
  • thermocouple was covered in Teflon tape to prevent any reaction with the leaching solution. The temperature was maintained at 80°C and the thermocouple reading was periodically cross checked with a glass thermometer. Sampling and reagent dosing
  • the dilution solution was comprised of 1v% HCI, 1v%HN0 3 , (by volume taking into account that the HCI is 32wt.% pure and the HNO3 is 70wt.% pure).
  • the dilution solution also contained 0.2wt.% La added as La 2 0 3 powder to assist with the atomic absorption measurement.
  • the pH and ORP of the remaining sample was measured and solution or slurry was returned to the reactor. ORP is measured using a Pt vs. Ag/AgCI reference system (recorded as mV Ag/AgCI).
  • the pH probe/meter was calibrated daily using pH 4.00 and 6.88 buffers.
  • pool chlorine containing calcium hypochlorite
  • additional acid may be required to maintain the acidic conditions as it may contain a significant amount of Ca(OH) 2 which neutralizes the acid.
  • the acid concentration needs to be sufficient to dissolve the alumina matrix and prevent the noble metals precipitating as hydroxides.
  • thermocouple was covered in Teflon tape so that the metal does not react with the solution.
  • the temperature was cross checked with a glass thermometer.
  • the dissolved (oxidized) metals were recovered from solution by adding a more reactive metal powder to the solution.
  • the stoichiometric amount of powder required is calculated by the following reactions based on the measured solution Pt concentration.
  • Iron powder (assume Fe is oxidized to Fe 2+ ):
  • ICP Induction Coupled Plasma
  • the AAS instrument used is a Perkin Elmer. AAnalyst 400.
  • the standards for AAS were prepared with platinum concentrations of 0, 5, 0, 20 and 30 mg/L. A 50mL volume of each standard was prepared.
  • the dilution solution for the standards consisted of 1 % HCI, 1 % HN0 3 and 0.2% La, as well as 47.6g/L of MgC .
  • the amount of MgC was calculated by taking into account the fact that the original 5M leach solution was diluted 10x when the samples were taken and so the samples contained approximately 47.6g/L of MgCfe.
  • the magnesium was added to matrix match with the magnesium in the samples being analysed (assumed 10X dilution). The Lanthanum was added to counter the depressing effect of magnesium on the platinum signal in order to obtain linear calibration.

Abstract

L'invention concerne un procédé de récupération d'un métal tel qu'un métal noble à partir d'un matériau source impur par mise en contact du matériau source avec une solution de lixiviation comprenant un halogénure métallique, un oxydant et un acide. La solution de lixiviation contenant le métal cible est ensuite séparée du matériau source restant, puis traitée avec un réducteur pour récupérer le métal sous forme solide. La grande majorité des ions halogénure présents dans la solution de lixiviation, qui agissent pour solubiliser le métal, sont donnés par l'halogénure métallique plutôt que par une source acide.
PCT/AU2011/000726 2010-06-15 2011-06-15 Procédé de récupération d'un métal WO2011156861A1 (fr)

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Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013152424A1 (fr) * 2012-04-09 2013-10-17 Process Research Ortech Inc. Procédé aux chlorures pour la lixiviation d'or
WO2013152423A1 (fr) * 2012-04-09 2013-10-17 Process Research Ortech Inc. Procédé pour l'extraction d'éléments terres rares
WO2015140663A1 (fr) * 2014-03-18 2015-09-24 Kadam Subhash Traitements métallurgiques de métaux nobles contenus dans le sol de mangalwedha
EP2985354B1 (fr) 2014-11-10 2016-10-19 Heraeus Deutschland GmbH & Co. KG Procédé d'extraction de métal précieux à partir de support de catalyseur contenant des métaux précieux
CN106661663A (zh) * 2014-02-25 2017-05-10 恩特格里斯公司 用于选择性去除贵金属的湿基制剂
CN109943718A (zh) * 2019-04-11 2019-06-28 昆明理工大学 一种采用过硫酸盐作为氧化剂的卤化物提金方法
US10400306B2 (en) 2014-05-12 2019-09-03 Summit Mining International Inc. Brine leaching process for recovering valuable metals from oxide materials
US10544512B2 (en) 2014-02-24 2020-01-28 Nemaska Lithium Inc. Methods for treating lithium-containing materials
US10597305B2 (en) 2015-08-27 2020-03-24 Nemaska Lithium Inc. Methods for treating lithium-containing materials
US10633748B2 (en) 2012-04-23 2020-04-28 Nemaska Lithium Inc. Processes for preparing lithium hydroxide
US10800663B2 (en) 2012-05-30 2020-10-13 Nemaska Lithium Inc. Processes for preparing lithium carbonate
US11078583B2 (en) 2013-03-15 2021-08-03 Nemaska Lithium Inc. Processes for preparing lithium hydroxide
US11083978B2 (en) 2016-08-26 2021-08-10 Nemaska Lithium Inc. Processes for treating aqueous compositions comprising lithium sulfate and sulfuric acid
US11142466B2 (en) 2017-11-22 2021-10-12 Nemaska Lithium Inc. Processes for preparing hydroxides and oxides of various metals and derivatives thereof
US11697861B2 (en) 2013-10-23 2023-07-11 Nemaska Lithium Inc. Processes for preparing lithium carbonate

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1228989A (fr) * 1984-10-05 1987-11-10 Philip A. Distin Extraction des metaux precieux presents dans des matieres
JP2001316736A (ja) * 2000-03-03 2001-11-16 Nippon Mining & Metals Co Ltd 銀の回収方法
WO2005049872A1 (fr) * 2003-11-19 2005-06-02 Process Research Ortech Inc. Procede de recuperation de titane dans des milieux de chlorures melanges

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1228989A (fr) * 1984-10-05 1987-11-10 Philip A. Distin Extraction des metaux precieux presents dans des matieres
JP2001316736A (ja) * 2000-03-03 2001-11-16 Nippon Mining & Metals Co Ltd 銀の回収方法
WO2005049872A1 (fr) * 2003-11-19 2005-06-02 Process Research Ortech Inc. Procede de recuperation de titane dans des milieux de chlorures melanges

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013152423A1 (fr) * 2012-04-09 2013-10-17 Process Research Ortech Inc. Procédé pour l'extraction d'éléments terres rares
US20130283977A1 (en) * 2012-04-09 2013-10-31 Vaikuntam I. Lakshmanan Process for extraction of rare earth elements
US9115419B2 (en) * 2012-04-09 2015-08-25 Process Research Ortech Inc. Process for extraction of rare earth elements
WO2013152424A1 (fr) * 2012-04-09 2013-10-17 Process Research Ortech Inc. Procédé aux chlorures pour la lixiviation d'or
US10633748B2 (en) 2012-04-23 2020-04-28 Nemaska Lithium Inc. Processes for preparing lithium hydroxide
US11634336B2 (en) 2012-05-30 2023-04-25 Nemaska Lithium Inc. Processes for preparing lithium carbonate
US10800663B2 (en) 2012-05-30 2020-10-13 Nemaska Lithium Inc. Processes for preparing lithium carbonate
US11254582B2 (en) 2012-05-30 2022-02-22 Nemaska Lithium Inc. Processes for preparing lithium carbonate
US11078583B2 (en) 2013-03-15 2021-08-03 Nemaska Lithium Inc. Processes for preparing lithium hydroxide
US11697861B2 (en) 2013-10-23 2023-07-11 Nemaska Lithium Inc. Processes for preparing lithium carbonate
US10544512B2 (en) 2014-02-24 2020-01-28 Nemaska Lithium Inc. Methods for treating lithium-containing materials
US11519081B2 (en) 2014-02-24 2022-12-06 Nemaska Lithium Inc. Methods for treating lithium-containing materials
US11085121B2 (en) 2014-02-24 2021-08-10 Nemaska Lithium Inc. Methods for treating lithium-containing materials
EP3110982A4 (fr) * 2014-02-25 2017-11-22 Entegris, Inc. Formulations à base humide pour l'élimination sélective de métaux nobles
CN106661663A (zh) * 2014-02-25 2017-05-10 恩特格里斯公司 用于选择性去除贵金属的湿基制剂
WO2015140663A1 (fr) * 2014-03-18 2015-09-24 Kadam Subhash Traitements métallurgiques de métaux nobles contenus dans le sol de mangalwedha
US10400306B2 (en) 2014-05-12 2019-09-03 Summit Mining International Inc. Brine leaching process for recovering valuable metals from oxide materials
EP2985354B1 (fr) 2014-11-10 2016-10-19 Heraeus Deutschland GmbH & Co. KG Procédé d'extraction de métal précieux à partir de support de catalyseur contenant des métaux précieux
US10597305B2 (en) 2015-08-27 2020-03-24 Nemaska Lithium Inc. Methods for treating lithium-containing materials
US11083978B2 (en) 2016-08-26 2021-08-10 Nemaska Lithium Inc. Processes for treating aqueous compositions comprising lithium sulfate and sulfuric acid
US11142466B2 (en) 2017-11-22 2021-10-12 Nemaska Lithium Inc. Processes for preparing hydroxides and oxides of various metals and derivatives thereof
US11542175B2 (en) 2017-11-22 2023-01-03 Nemaska Lithium Inc. Processes for preparing hydroxides and oxides of various metals and derivatives thereof
CN109943718A (zh) * 2019-04-11 2019-06-28 昆明理工大学 一种采用过硫酸盐作为氧化剂的卤化物提金方法

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