[go: up one dir, main page]

WO2025010466A1 - Procédé de valorisation de boue rouge - Google Patents

Procédé de valorisation de boue rouge Download PDF

Info

Publication number
WO2025010466A1
WO2025010466A1 PCT/AU2024/050724 AU2024050724W WO2025010466A1 WO 2025010466 A1 WO2025010466 A1 WO 2025010466A1 AU 2024050724 W AU2024050724 W AU 2024050724W WO 2025010466 A1 WO2025010466 A1 WO 2025010466A1
Authority
WO
WIPO (PCT)
Prior art keywords
iron
solution
values
iron values
precipitate
Prior art date
Legal status (The legal status 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 status listed.)
Pending
Application number
PCT/AU2024/050724
Other languages
English (en)
Inventor
Terrence John O'CONNOR
Nicholas James Welham
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Peloton Resources Pty Ltd
Original Assignee
Peloton Resources Pty Ltd
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
Priority claimed from AU2023902223A external-priority patent/AU2023902223A0/en
Application filed by Peloton Resources Pty Ltd filed Critical Peloton Resources Pty Ltd
Publication of WO2025010466A1 publication Critical patent/WO2025010466A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
    • C01F7/04—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom
    • C01F7/06—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom by treating aluminous minerals or waste-like raw materials with alkali hydroxide, e.g. leaching of bauxite according to the Bayer process
    • C01F7/066—Treatment of the separated residue
    • 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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
    • C01F7/20—Preparation of aluminium oxide or hydroxide from aluminous ores using acids or salts
    • C01F7/22—Preparation of aluminium oxide or hydroxide from aluminous ores using acids or salts with halides or halogen acids
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G49/00—Compounds of iron
    • C01G49/02—Oxides; Hydroxides
    • C01G49/06—Ferric oxide [Fe2O3]
    • 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
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/005—Preliminary treatment of scrap
    • 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
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/02—Roasting 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
    • C22B21/00—Obtaining aluminium
    • C22B21/0015—Obtaining aluminium by wet processes
    • C22B21/0023—Obtaining aluminium by wet processes from waste materials
    • 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
    • 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
    • C22B3/28—Amines
    • 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
    • C22B3/28—Amines
    • C22B3/282—Aliphatic amines
    • 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
    • C22B3/38—Treatment or purification of solutions, e.g. obtained by leaching by liquid-liquid extraction using organic compounds containing phosphorus
    • 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
    • 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
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/006—Wet processes
    • C22B7/007—Wet processes by acid leaching
    • 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 for producing valuable products from bauxite residue produced via the Bayer process, a waste known as red mud. More particularly, the present invention relates to a method for recovering valuable products including but not limited to, aluminium and iron from red mud using a combination of pyrometallurgy and hydrometallurgy.
  • Red mud is a very significant waste stream from the production of aluminium by the Bayer Process.
  • Red mud is the result of the precipitation of, predominantly, iron from the alkaline solution which retains the majority of the aluminium.
  • some Bayer Process operations also precipitate a significant fraction of their aluminium and silica making the red mud a poorly crystalline mixture of iron (hydr-)oxides, aluminium (hydr-)oxides and silica.
  • Also reporting to red mud are any insoluble phases present in the original bauxite.
  • Prior patent application AU 2014339746 taught a method whereby red mud could be converted to high purity alumina (HPA) and high purity iron oxide by a process of calcination, leaching, precipitation of iron, solvent extraction of aluminium, precipitation of aluminium and calcination to HPA.
  • HPA high purity alumina
  • the process taught in AU 2014339746 removes the iron from the solution by adjusting pH using a base, resulting in precipitation of the iron, but also the loss of a significant fraction of the dissolved aluminium.
  • the loss of the aluminium fraction from the process stream has been considered as an impediment to widespread adoption of the process taught in AU 2014339746.
  • Prior patent application AU 2021902602 improved on this by using a process of calcination, leaching, solvent extraction of iron, precipitation of iron, solvent extraction of aluminium, precipitation of aluminium and calcination to HPA.
  • the process taught in AU 2021902602 removes the iron from the solution using solvent extraction rather than precipitation. This results in a purer iron product with low aluminium losses.
  • the economics of the latter process hinge on the production and sale of high purity alumina for which the market, although growing will remain relatively small. It appears unlikely that widespread adoption of this process will occur, because an increase supply of high purity alumina may result in a significant reduction in its sale price, thus impacting its overall economics.
  • the present invention has as one object, to provide a method which can overcome the abovementioned problems, or to at least provide a useful alternative.
  • the invention resides in a method for recovering iron and aluminium from red mud, the method comprising the steps of leaching the red mud in hydrochloric acid, removing the insoluble material, extracting the iron from solution, separately treating the iron-rich solution and aluminium -rich solution to produce high value products.
  • a method for recovering iron values and aluminium values from a Bayer process red mud residue comprising: leaching the residue in aqueous acid to dissolve said iron values and said aluminium values, and separating a solubilised leachate therefrom; performing on said solubilised leachate, a solvent extraction of iron values using an iron values preferencing immiscible organic extractant to produce an iron values loaded organic extractant and a raffinate stripped of iron values; stripping iron values from said iron values loaded organic extractant into aqueous solution to form an iron values loaded aqueous solution; and subjecting said raffinate directly to treatment with an alkaline reagent to precipitate said aluminium values therefrom.
  • the step of leaching the residue is performed using aqueous acid in sufficient quantity to produce said solubilised leachate containing free acid in solution.
  • the step of leaching the residue is performed using hydrochloric acid.
  • said iron values preferencing organic extractant is selected from the group comprising liquid organophosphorus extractants, amine extractants and/or combinations thereof.
  • the step of stripping iron values from said iron values loaded organic extractant into aqueous solution is performed using a weak mineral acid.
  • the mineral acid may be hydrochloric acid, consistent with its use elsewhere in the process, and avoiding the need for additional reagents.
  • the concentration of HCI may range from 50 g/litre to saturation.
  • the step of stripping iron values from said iron values loaded organic extractant into aqueous solution is performed using water.
  • the step of stripping iron values from said iron values loaded organic extractant into aqueous solution is performed using an aqueous solution maintained to ⁇ pH3.0 using hydrochloric acid as-required, to prevent iron precipitation.
  • hydrochloric acid as-required
  • Other acids may be used, however the preference is to use hydrochloric acid.
  • the stripping of iron values from the organic extractant may be followed by recovery of iron values from the iron values loaded aqueous solution.
  • said iron values loaded organic extractant is subjected to treatment with an aqueous scrub solution to remove impurities.
  • the aqueous scrub solution comprises an acid solution and/or a solution of a ferric iron salt.
  • the acid and/or ferric ions replace the impurities in the organic producing an acid/iron-enriched impurity-depleted organic solution and an acid/iron- depleted impurity-enriched scrub solution.
  • the step of subjecting said raffinate directly to treatment with an alkaline reagent to precipitate said aluminium values therefrom comprises adjusting the pH of said raffinate using said alkaline reagent in optimum quantity to produce an aluminous precipitate.
  • the alkaline reagent is preferably an alkali or alkaline earth metal hydroxide or carbonate.
  • the alkaline reagent is selected from one, or more, of calcium carbonate, calcium oxide, calcium hydroxide, sodium hydroxide and sodium carbonate. This is introduced to the raffinate in finely divided form in order to have the reaction proceed at an optimum speed.
  • the alkaline reagent is sodium hydroxide.
  • the aluminium may be precipitated as aluminium chloride hexahydrate (ACH) by increasing the concentration hydrochloric acid by adding concentrated hydrochloric acid and/or gaseous HCI.
  • ACH aluminium chloride hexahydrate
  • the step of subjecting said raffinate directly to treatment with an alkaline reagent to precipitate said aluminium values therefrom may be performed at elevated temperature or elevated temperature and elevated pressure.
  • the precipitation may also be assisted with the introduction of aluminous seed crystals.
  • the aluminous precipitate and solution may be aged, preferably at elevated temperature in order to agglomerate and settle the precipitate, prior to its separation by filtration from the aqueous phase.
  • the precipitate may be calcined to recover purified alumina. If the precipitate is ACH, the gaseous HCI and steam evolved may be recycled within the process as either hydrochloric acid or as gaseous HCI and water.
  • the red mud is calcined to render the aluminium more soluble in the subsequent leaching stage.
  • the calcination is believed to convert unleachable aluminium phases to amorphous phases which are soluble during leaching. For red mud containing low Al values, calcination is unlikely to be economic.
  • the red mud is calcined at least at 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, or 700°C.
  • the red mud is calcined at up to 800°C.
  • the red mud is calcined at between 300 and 800°C. More preferably, the red mud is calcined at between 400 and 700°C. Most preferably, the red mud is calcined at between 400 and 600°C.
  • the red mud is calcined for a period between 0.25 and 24.0 hours.
  • the red mud is calcined for a period between 0.25 and 12.0 hours.
  • the red mud is calcined for a period between 0.25 and 6.0 hours.
  • the red mud is calcined for a period between 0.25 and 4.0 hours. More preferably, the red mud is calcined for a period between 0.25 and 3.0 hours.
  • the red mud is calcined for a period between 0.25 and 2.0 hours.
  • the red mud is calcined in air.
  • the effect of calcination is to alter the crystalline state of the alumina and iron present in the red mud. Through a combination of phase changes, amorphization and crystallisation the solubility of the iron and aluminium can be enhanced. At the lower temperatures, weakly bound waters of crystallisation and water within amorphous phases are driven off. The upper limit, is where there is reaction between the separate phases present within the red mud resulting in the formation of phases which are of lower solubility.
  • the concentration of the hydrochloric acid used is between 100 g/L and saturation.
  • the concentration of the hydrochloric acid used is between 100 g/L and 350g/L saturation. More preferably, the concentration of the hydrochloric acid used is between 200 g/L and 350g/L. Most preferably, the concentration of the hydrochloric acid used is between 250g/L and 350g/L.
  • the leaching occurs between ambient temperature and the boiling point of the acid solution.
  • the leaching occurs between 40°C and the boiling point of the acid solution.
  • the leaching occurs between 50°C and the boiling point of the acid solution.
  • the leaching occurs between 60°C and the boiling point of the acid solution.
  • the leaching occurs between 70°C and the boiling point of the acid solution.
  • the leaching occurs between 80°C and the boiling point of the acid solution. More preferably, the leaching occurs between 90°C and the boiling point of the acid solution.
  • the leaching occurs between 100°C and the boiling point of the acid solution.
  • the leaching takes place at atmospheric pressure.
  • the leaching takes place for between 0.05 and 6h.
  • the leaching takes place for between 0.1 and 4h.
  • the leaching takes place for between 0.5 and 4h. More preferably, the leaching takes place for between 1.0 and 4h. Most preferably, the leaching takes place for between 1 .0 and 3h.
  • both fresh red mud and HCI are constantly added to the leach vessel in order to maximise the resultant concentrations of iron and aluminium in solution.
  • the rates of addition are preferably controlled to ensure that the aqueous leach solution does not boil during the leaching. It will be recognised by those skilled in the art that the leach is most likely to be limited in maximum quantity of red mud that can be processed in a given volume of solution by the necessity to agitate an increasingly viscous slurry and filter said slurry in order to recover the iron-bearing solution.
  • the HCI is preferably supplied in gaseous form into the solution in order to build up the HCI concentration as HCI is depleted as the reaction proceeds.
  • the solution will contain between 1 and 250g/L of free acid.
  • the solution will contain between 1 and 150g/L of free acid.
  • after leaching the solution will contain between 1 and 10Og/L of free acid. More preferably, after leaching the solution will contain between 1 and 75g/L of free acid. More preferably, after leaching the solution will contain between 1 and 50g/L of free acid. Most preferably, after leaching the solution will contain between 1 and 10g/L of free acid.
  • a slurry comprising acid solution and red mud is formed. The density/viscosity of the slurry is a function of the solubility of target aluminium values in the red mud, and slurry density/viscosity needs to be tailored to maximise the leaching of those aluminium values.
  • the slurry is separated using conventional means into a solution containing the soluble elements and a solid material composed of insoluble phases.
  • the solid phase will be predominantly silica-based but will, depending upon the source red mud, also contain titanium and rare earth elements. This residue may be further processed.
  • the solution is treated to selectively remove iron using solvent extraction.
  • the solvent extraction is run in countercurrent mode.
  • the concentration of iron extractant in the organic solution is between 0.5 and 95vol%.
  • the concentration of iron extractant in the organic solution is between 1 and 80vol%.
  • the concentration of iron extractant in the organic solution is between 5 and 80vol%.
  • the concentration of iron extractant in the organic solution is between 10 and 80vol%. More preferably, the concentration of iron extractant in the organic solution is between 20 and 80vol%. Most preferably, the concentration of iron extractant in the organic solution is between 30 and 80vol%.
  • the iron extractant is selected from the group comprising liquid organophosphorus extractants, amine extractants and/or combinations thereof.
  • the organophosphorus extractant is a derivative of phosphoric, phosphonic, phosphinic or dithiophosphinic acid.
  • the amine extractant is a trialkyl amine or a quaternary amine or a derivative thereof.
  • the organophosphorus extractant is tributyl phosphate, also known as TBP, with the formula OP(OC4Hg)3 and has the CAS Number 126-73-8.
  • the organophosphorus extractant is trioctylphosphine oxide, also known as TOPO, with the formula OP(C8HI?)3 and has the CAS Number 78-50-2.
  • the amine extractant is N, N-dioctyl-1 - octanamine, also known as Alamine 3365; Alamine 336S; Farmin 08; Octanamine; Tricaprylamine; Tridioctylamine; Tri-n-octylamine; Tri-n-caprylylamine; Trioctylamine with the CAS number 11 16-76-3.
  • the extractant is the majority component of a mixture of tri C8-10 Alkyl Amines known as Alamine 336, CAS number 57176-40-6
  • the amine extractant is N-Methyl-N,N,N- trioctylammonium chloride, also known as Aliquat 336, Starks' catalyst; Tricaprylmethylammonium chloride, Methyltrioctylammonium chloride, CAS number 63393-96-4
  • 1 -decanol CH 3 (CH 2 ) 9 OH, CAS number 112- 30-1 , is added at 2-20 volume% to the organic phase.
  • 1 -decanol is added at 5-15 volume% to the organic phase.
  • 1 -decanol is added at 8 - 12 volume% to the organic phase.
  • tributyl phosphate is added at 2-20volume% to the organic phase. In a preferred form of the invention tributyl phosphate is added at 5-15 volume% to the organic phase. In a highly preferred form of the invention tributyl phosphate is added at 8-12 volume% to the organic phase.
  • the kerosene used contains 50-100% aliphatic hydrocarbons. In a preferred form of the invention the kerosene used contains 80-100% aliphatic hydrocarbons. In a highly preferred form of the invention the kerosene used contains 90-100% aliphatic hydrocarbons.
  • the selection of the optimum organic composition is largely experimental. In general, high extractant concentrations can, but not always, result in high organic viscosity which results in poor separation of the organic and aqueous phases. Low extractant concentrations result in poor economics due to the necessity to use a larger total volume of organic for the same metal transfer as a higher extractant concentration organic.
  • the aqueous solution produced after removing the iron contains high-aluminium and low-iron.
  • the aluminium from this solution may be recovered into a solid phase by methods such as precipitation, thermal hydrolysis or pyrohydrolysis.
  • the organic solution from the solvent extraction of iron may be treated to remove impurities by contacting the organic solution with an aqueous “scrubbing” solution which selectively removes the impurities from the organic without removing iron from the organic.
  • the scrubbing solution is an acid.
  • the scrubbing solution is a solution of ferric iron.
  • the scrubbing solution is an acid containing ferric iron.
  • the scrubbing solution is hydrochloric acid containing ferric chloride.
  • the scrubbing solution is a recycled portion of the iron values loaded aqueous solution.
  • the acid I ferric ions present in the scrub solution replace the more weakly bound impurity ions within the organic producing an organic which is enriched in iron I acid and depleted in impurities and a solution depleted in iron I acid and enriched in impurity ions.
  • the scrubbing solution contains a hydrochloric acid concentration between 0.01 g/L and saturation. In a preferred form of the invention, the scrubbing solution contains a hydrochloric acid concentration between 0.1 g/L and saturation. In a preferred form of the invention, the scrubbing solution contains a hydrochloric acid concentration between 1 g/L and saturation. In a most preferred form of the invention, the scrubbing solution contains a hydrochloric acid concentration between 10g/L and saturation.
  • the scrubbing solution contains a ferric chloride concentration between 0.01 g/L and saturation. In a preferred form of the invention, the scrubbing solution contains a ferric chloride concentration between 0.1 g/L and saturation. In a preferred form of the invention, the scrubbing solution contains a ferric chloride concentration between 1 g/L and saturation. In a most preferred form of the invention, the scrubbing solution contains a ferric chloride concentration between 10g/L and saturation.
  • the scrubbing solution contains both hydrochloric acid and ferric chloride within the ranges specified above.
  • the solution depleted in iron I acid and enriched in impurity ions is recycled to the leaching stage.
  • the scrubbing solution is the solution produced by stripping the iron from the organic.
  • the organic solution from the solvent extraction iron is treated to recover the iron. This is achieved by contacting the iron-loaded organic solution with an iron-depleted aqueous solution such that the iron transfers back in to the aqueous phase from the organic phase giving an iron-depleted organic phase and an iron-enriched aqueous phase.
  • the iron-depleted aqueous solution is selected from the group: water and acid.
  • the iron-depleted aqueous solution is water.
  • the acid is selected from the group of mineral acids: hydrochloric, sulphuric, nitric and phosphoric, or mixtures thereof.
  • the concentration of the acid used contains up to around 5g/L, 10g/L, 20g/L, or 50g/L of free acid.
  • the aqueous and organic phases in the solvent exchange run counter-current.
  • the iron-enriched aqueous solution can be treated to produce an iron-bearing product by one, or more of the following methods: electrowinning, reduction, oxidation, precipitation, thermal hydrolysis, pyrohydrolysis and/or crystallisation.
  • the iron is precipitated by adjustment of the pH by adding an alkali.
  • the alkali may be selected from one, or more of, sodium hydroxide, potassium hydroxide, calcium oxide, calcium hydroxide, magnesium oxide, magnesium hydroxide, aqueous ammonium hydroxide or anhydrous ammonia.
  • the iron is precipitated by adding a precipitating agent, pH adjustment may be required.
  • the precipitating agent may be selected from one, or more of, phosphoric acid, sodium phosphate, ammonium phosphate, sodium carbonate, ammonium carbonate, oxalic acid or sodium oxalate.
  • the precipitation takes place at elevated temperature.
  • the precipitation occurs between ambient temperature and the boiling point of the iron-bearing solution.
  • the precipitation occurs between 30°C and the boiling point of the iron-bearing solution.
  • the precipitation occurs between 50°C and the boiling point of the iron-bearing solution.
  • the precipitation occurs between 70°C and the boiling point of the iron-bearing solution.
  • the precipitation occurs between 90°C and the boiling point of the iron-bearing solution.
  • the precipitation occurs between 100°C and the boiling point of the iron-bearing solution.
  • seed crystals of the desired product are added to the precipitation.
  • the conditions for precipitation of the iron product can be adjusted to produce a range of particle sizes and shapes in addition to forming different iron phases.
  • the iron product may be calcined in order to produce a product with specific physical and / or chemical characteristics.
  • the conditions for calcination of the iron product vary according to the starting phase and the desired product phase.
  • the iron-bearing solution is pyrohydrolysed at 500-1200°C to produce iron oxide, steam and gaseous HCI.
  • the steam is condensed and may be used to dissolve the HCI to be recycled within the process as hydrochloric acid.
  • the iron product contains ⁇ 2.0% impurities. In a preferred form of the invention, the iron product contains ⁇ 1.0% impurities. In a preferred form of the invention, the iron product contains ⁇ 0.5% impurities. In a preferred form of the invention, the iron product contains ⁇ 0.2% impurities. In a preferred form of the invention, the iron product contains ⁇ 0.1 % impurities.
  • the iron product is goethite, FeOOH.
  • the iron product is magnetite, FesO4.ln a most preferred form of the invention, the iron product is hematite, Fe2Os.
  • the iron solution is treated by thermal hydrolysis in order to simultaneously precipitate hematite and regenerate HCI for recycle to the leach.
  • the aluminium may be recovered by precipitation.
  • the precipitation is achieved by raising the pH to a range of 4-10.
  • the precipitation is achieved by raising the pH to a range of 5-9. More preferably, the precipitation is achieved by raising the pH to a range of 6-8. Most preferably, the precipitation is achieved by raising the pH to a range of 6.5-7.5
  • aluminium is amphoteric and is soluble in both acid and alkaline solutions.
  • the optimum pH is above that where the solubility of aluminium is at a minimum and below that where the solubility substantially increases due to formation of the tetrahydroaluminate ion, AI(OH)
  • the precipitating agent may be selected from sodium hydroxide, potassium hydroxide, limestone, calcium oxide, calcium hydroxide, ammonia, magnesium hydroxide, magnesium oxide.
  • the precipitating agent is soluble in water.
  • the precipitating agent is calcium hydroxide.
  • the precipitating agent is sodium hydroxide, NaOH.
  • the precipitation produces pseudoboehmite, gibbsite, bayerite or diaspore.
  • the precipitation will be performed at ambient temperature.
  • the precipitation will be performed at elevated temperature.
  • the precipitation will be performed between 30°C and the boiling point of the solution.
  • the precipitation will be performed between 40°C and the boiling point of the solution.
  • the precipitation will be performed between 50°C and the boiling point of the solution.
  • the precipitation will be performed between 60°C and the boiling point of the solution.
  • the precipitation will be performed between 70°C and the boiling point of the solution.
  • the precipitation will be performed between 80°C and the boiling point of the solution.
  • the precipitation will be performed between 90°C and the boiling point of the solution.
  • the precipitation may also take place in an autoclave utilising an elevated pressure to prevent the boiling of the solution above its boiling point at atmospheric pressure.
  • seed crystals are added to the precipitation stage.
  • the seed crystals may be derived by recycling the finer particle sizes separated from the product precipitate.
  • the precipitate is washed prior to drying and/or calcination.
  • the washing solution is high purity water.
  • the precipitate is filtered and used without further treatment.
  • the precipitate is recycled back to the Bayer Process plant.
  • the filtrate is further treated to concentrate and recover the reagents used so they can be recycled. This may consist of a process consisting of one, or more, of, reverse osmosis, nanofiltration, electrodialysis, ultrafiltration and electrolysis.
  • the aluminium may be precipitated as aluminium chloride hexahydrate (ACH) by increasing the concentration hydrochloric acid by adding concentrated hydrochloric acid and/or gaseous HCI.
  • ACH aluminium chloride hexahydrate
  • the precipitate may be calcined.
  • the precipitate is separated from the solution, and calcined to drive off water and produce alumina, AI2O3.
  • the precipitate is dried prior to calcination.
  • calcination occurs in two stages. In the first stage, the precipitate is dehydrated to AI2O3. In the second stage, the AI2O3 is transformed to the required crystalline form. In a highly preferred form, both stages of calcination occur within a single piece of equipment through which the precipitate proceeds or is transported.
  • the precipitate is calcined at above 300°C.
  • the precipitate is calcined at above 400°C.
  • the precipitate is calcined at above 500°C.
  • the precipitate is calcined at above 600°C.
  • the precipitate is calcined at above 700°C.
  • the precipitate is calcined at above 800°C.
  • the precipitate is calcined between 500 and 1200°C.
  • the precipitate is calcined between 600 and 1100°C. More preferably, the precipitate is calcined between 700 and 1000°C. Most preferably, the precipitate is calcined between 750 and 850°C.
  • the precipitate is calcined for between 15 minutes and 6 hours.
  • the precipitate is calcined for between 30 minutes and 6 hours.
  • the precipitate is calcined for between 45 minutes and 6 hours. More preferably, the precipitate is calcined for between 1 hour and 4 hours. Most preferably, the precipitate is calcined for between 2 hours and 4 hours.
  • a single calcination stage may incorporate both calcination stages simply by moving the precipitate through the calciner. The initial stage of dehydration will occur whilst the precipitate is heating up to the temperature required for the second stage.
  • thermal processing of aluminium precipitates is a complex process capable of producing a wide range of products.
  • the optimum time and temperature of calcination will be highly dependent upon the final product required.
  • the calcination will also produce gaseous HCI and gaseous water. These can be captured and recycled within the overall process.
  • red mud 1 is fed into a heated tank 2 where it is mixed with water 3 and concentrated hydrochloric acid 4 to give a solution containing 250g/L hydrochloric acid and heated to around 90°C.
  • the residence time within the leaching tank is around 180min.
  • the filter cake 6 is recovered from the filter 5 and may be sold as a feed to titanium or rare earth processing plants, further processed, or simply disposed of.
  • the leach solution proceeds via feed line 7 to the iron loading stage reactor 8 of the Fe Solvent Extraction (FeSX) circuit.
  • FeSX Fe Solvent Extraction
  • the iron-bearing aqueous solution is mixed with an organic solution of iron extractant 9 comprising 50 vol% Alamine 336 and 10% 1 -decanol dissolved in kerosene which is recycled from the FeSX strip stage reactor 11 of the FeSX circuit.
  • Mixing takes place for 60 seconds during which the iron transfers from the aqueous phase into the organic phase whilst aluminium remains in the aqueous phase.
  • the phases are allowed to settle, the iron-depleted aqueous phase proceeds via feed line 17 to aluminium precipitation 18 whilst the iron-loaded organic phase 10 moves into the FeSX strip stage reactor 11 where it is mixed with water 12 for 60 seconds transferring the iron from the organic to the water resulting in regenerated Alamine 336 which is recycled to the FeSX loading stage via feed line 9 and an iron bearing aqueous solution 13 which proceeds to further processing.
  • solvent extraction processes are most commonly conducted in several stages with the organic and aqueous phases moving in a counter-current manner. This arrangement is the most efficient at maximising the recovery of the metal of interest whilst also maximising the concentration of metal within the organic phase.
  • the highest concentration aqueous feed is contacted with an organic phase within which there is also a high, but not maximised, concentration of metal, a small amount of metal is transferred into the organic maximising the concentration of metal within the organic.
  • the fully loaded organic phase then proceeds to scrub or stripping stages.
  • the slightly depleted aqueous phase proceeds to a second stage where it is contacted with an organic phase which is less concentrated and further metal transfers increasing the concentration within the organic. Such stages continue until the largely depleted aqueous phase is contacted with freshly regenerated organic from the strip stages maximising the metal extraction from the aqueous solution.
  • the aluminium-bearing solution proceeds via feed line 17 into a precipitation unit 18 along with a slurry of limestone 19 which raises the pH and forms an aluminium precipitate.
  • the resultant slurry 20 is fed into a filter 22 where the solution 26 and solids 24 are separated.
  • the solid filter cake within the filter 22 may be washed with water 23 prior to discharge, the wash water being combined with the filtrate 26.
  • the solids 24 may be used as a feed into a Bayer Process plant. It is equally possible that the precipitate 21 may be directly fed into the Bayer Process plant without undertaking the solid-liquid separation step 22.
  • the iron strip solution 13 is fed into a heated reactor 14 where the solution is boiled, this splits the iron chloride into hematite, Fe2Os 16 and a gas phase comprising water and hydrogen chloride 15.
  • the hematite 16 is a final product and may be further processed into a form most suitable for sale, e.g. pelletising.
  • the gas phase 15 can be condensed and recycled to the leaching stage as hydrochloric acid.
  • the Alamine 336 was extremely effective at selectively extracting the iron from the feed solution with all other elements remaining within the raffinate. It is reasonably expected that further contacts between the raffinate and Alamine 336 solutions would further reduce the concentration of iron within the raffinate.

Landscapes

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

Abstract

L'invention concerne un procédé pour la récupération d'éléments valorisables en fer et d'éléments valorisables en aluminium à partir d'un résidu de boue rouge de procédé Bayer 1 consistant à : lixivier 2 le résidu dans un acide aqueux pour dissoudre les éléments valorisables en fer et les éléments valorisables en aluminium, et séparer 5 un lixiviat solubilisé 7 à partir de celui-ci; réaliser une extraction par solvant 8 sur le lixiviat solubilisé d'éléments valorisables en fer à l'aide d'un agent d'extraction organique non miscible à préférence pour les éléments valorisables en fer pour produire un agent d'extraction organique chargé en éléments valorisables en fer et un raffinat dont les éléments valorisables en fer ont été extraits; extraire 11 des éléments valorisables en fer à partir de l'agent d'extraction organique chargé en éléments valorisables en fer dans une solution aqueuse pour former une solution aqueuse chargée en éléments valorisables en fer 13; et soumettre le raffinat directement à un traitement par un réactif alcalin 19 pour précipiter des éléments valorisables en aluminium à partir de celui-ci (Figure 1).
PCT/AU2024/050724 2023-07-11 2024-07-03 Procédé de valorisation de boue rouge Pending WO2025010466A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU2023902223 2023-07-11
AU2023902223A AU2023902223A0 (en) 2023-07-11 Method For Valorising Red Mud

Publications (1)

Publication Number Publication Date
WO2025010466A1 true WO2025010466A1 (fr) 2025-01-16

Family

ID=94214439

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU2024/050724 Pending WO2025010466A1 (fr) 2023-07-11 2024-07-03 Procédé de valorisation de boue rouge

Country Status (1)

Country Link
WO (1) WO2025010466A1 (fr)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015058239A1 (fr) * 2013-10-21 2015-04-30 Peloton Resources Pty Ltd Obtention de produits de grande valeur à partir d'une boue rouge résiduaire
WO2023019311A1 (fr) * 2021-08-19 2023-02-23 Peloton Resources Pty Ltd Méthode et installation de valorisation de boue rouge

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015058239A1 (fr) * 2013-10-21 2015-04-30 Peloton Resources Pty Ltd Obtention de produits de grande valeur à partir d'une boue rouge résiduaire
US20160289791A1 (en) * 2013-10-21 2016-10-06 Peloton Resources Pty Ltd Deriving high value products from waste red mud
WO2023019311A1 (fr) * 2021-08-19 2023-02-23 Peloton Resources Pty Ltd Méthode et installation de valorisation de boue rouge

Similar Documents

Publication Publication Date Title
RU2588960C2 (ru) Способы извлечения редкоземельных элементов из алюминийсодержащих материалов
RU2595178C2 (ru) Способ извлечения редкоземельных элементов и редких металлов
JP5894262B2 (ja) 種々の鉱石から希土類元素を回収する方法
US9963762B2 (en) Scandium recovery method
CN101842504B (zh) 从铝土矿石中提取铝和铁的工艺
AU2012286482B2 (en) Methods for separating iron ions from aluminum ions
CA2863755C (fr) Procedes d'obtention d'hematite
CA3230349A1 (fr) Methode et installation de valorisation de boue rouge
US10808296B2 (en) Selective recovery of rare earth metals from an acidic slurry or acidic solution
CN105271632A (zh) 一种电镀污泥综合回收的方法
WO2014032095A1 (fr) Procédé permettant l'extraction du scandium à partir de matériaux contenant du scandium
WO2019099859A1 (fr) Récupération sélective de métaux des terres rares à partir d'une suspension acide ou d'une solution acide
WO2025010466A1 (fr) Procédé de valorisation de boue rouge
CA3220775A1 (fr) Procede de production de materiaux d'aluminium de haute purete
WO2016108344A1 (fr) Procédé de collecte de scandium à partir de résidus générés lors du raffinage de minerai de nickel de faible qualité

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: 24838192

Country of ref document: EP

Kind code of ref document: A1