WO1995023240A1 - Procede d'extraction de l'uranium - Google Patents

Procede d'extraction de l'uranium Download PDF

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Publication number
WO1995023240A1
WO1995023240A1 PCT/AU1995/000095 AU9500095W WO9523240A1 WO 1995023240 A1 WO1995023240 A1 WO 1995023240A1 AU 9500095 W AU9500095 W AU 9500095W WO 9523240 A1 WO9523240 A1 WO 9523240A1
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WO
WIPO (PCT)
Prior art keywords
uranium
extraction
leaching
oxidant
ions
Prior art date
Application number
PCT/AU1995/000095
Other languages
English (en)
Inventor
Walter Hoecker
Original Assignee
Boc Gases Australia Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Boc Gases Australia Limited filed Critical Boc Gases Australia Limited
Priority to AU17491/95A priority Critical patent/AU698136B2/en
Publication of WO1995023240A1 publication Critical patent/WO1995023240A1/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
    • C22B60/00—Obtaining metals of atomic number 87 or higher, i.e. radioactive metals
    • C22B60/02—Obtaining thorium, uranium, or other actinides
    • C22B60/0204—Obtaining thorium, uranium, or other actinides obtaining uranium
    • C22B60/0217—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes
    • C22B60/0221—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes by leaching
    • C22B60/0226—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes by leaching using acidic solutions or liquors
    • 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
    • C22B60/00—Obtaining metals of atomic number 87 or higher, i.e. radioactive metals
    • C22B60/02—Obtaining thorium, uranium, or other actinides
    • C22B60/0204—Obtaining thorium, uranium, or other actinides obtaining uranium
    • C22B60/0217—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes
    • C22B60/0221—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes by leaching
    • 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
    • C22B60/00—Obtaining metals of atomic number 87 or higher, i.e. radioactive metals
    • C22B60/02—Obtaining thorium, uranium, or other actinides
    • C22B60/0204—Obtaining thorium, uranium, or other actinides obtaining uranium
    • C22B60/0217—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes
    • C22B60/0221—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes by leaching
    • C22B60/0247—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes by leaching using basic solutions or liquors

Definitions

  • This invention relates to the extraction of uranium, particularly from its ores, by an acidic or alkaline leaching process route. Background of the Invention.
  • the first such process is the alkaline or carbonate leaching process and the second such process is the acid extraction process.
  • Uranium is recovered from the process by precipitation of the sodium diuranate which is filtered and dried and exported for further processing.
  • the uranium oxide in the case of oxidic ores such as uraninite and pitchblende, is attacked by ferric ions which are generated by oxidation of ferrous ions generated by dissolution of iron present in the uranium ore by the acid, usually sulphuric acid though other mineral acids such as nitric and hydrochloric acids may be suitable for the purpose.
  • a further source of iron is the grinding media which grind the uranium ore to a suitable size for leaching.
  • Such attack converts U(IV) ions present in the ore to U(VI) ions in soluble uranyl cation (U0 2 2+) form which is amenable to recovery by solvent extraction or other suitable processing steps.
  • pyrolusite Mn0 2
  • sodium chlorate or other metallic compound oxidants
  • uranium processing plants may be required to pay high costs for pyrolusite or provide capital intensive grinding plant for the purpose of grinding.
  • grinding to 80% passing 0.074 mm is required. Such grinding is undoubtedly expensive and if it could be avoided a great benefit to uranium producers could be achieved.
  • pyrolusite introduces manganese or a non-payable element to the leach process.
  • manganese is subject to undesirable side reactions which reduce process efficiency and which may affect the efficiency of a solvent extraction process for recovery of uranium.
  • the chlorate ion tends to degrade to chloride ions which may attack electrodes used for the electrowinning of copper or other metals downstream of the leach circuit.
  • the present invention provides, in a first aspect, a process for the extraction of uranium from a uranium containing material by a leaching process comprising dissolution of said material, said dissolution being catalysed by a catalytic agent.
  • the leaching process may involve, for example, acid leaching by an acid such as sulphuric acid or Caro's acid; or alkaline leaching, by an alkaline agent, for example, alkaline carbonate.
  • acid leaching by an acid such as sulphuric acid or Caro's acid
  • alkaline leaching by an alkaline agent, for example, alkaline carbonate.
  • the present invention provides a process for the extraction of uranium from a uranium containing material by an acid leaching process comprising dissolution of a uranium mineral present in said uranium containing material by ferric ions wherein said ferric ions are generated by oxidation of ferrous ions at least a portion of which are formed by reaction of acid with iron or an iron containing mineral present in said uranium containing material, said oxidation being catalysed by a catalytic agent to thereby enable achievement of an effective ratio of said ferric to ferrous ions to provide substantial dissolution of said uranium mineral.
  • Adsorbent catalytic agents such as those based on carbon.e.g activated carbon, and ion exchange resins are especially convenient, readily obtainable catalytic agents for use in the process .
  • Other catalytic agents may also be employed. It is to be observed that, whereas contaminant metal ions are difficult and/or expensive to remove from solutions, extraction of solid catalytic agents, such as adsorbent activated carbon, is as straightforward as physical separation; for example by screening or filtration.
  • gaseous oxidants which are more economic and less detrimental to process efficiency than chlorate and pyrolusite, but presently not employed by the uranium industry, such as air, oxygen, ozone or an elemental oxygen containing gas having oxidising properties may be utilised under ambient pressure conditions in the presence of an adsorbent catalytic agent such as activated carbon.
  • gases are advantageous in that conventional gas delivery equipment may be used to supply them to a leaching vessel.
  • Such equipment has a substantial cost advantage over grinding equipment and operating expenses compare favourably with expenses for conventionally used oxidants.
  • contaminant metal ions such as manganese, chlorate or chloride
  • oxidants that could be used are solid oxidants selected, for example, from manganese dioxide, permanganates, peroxides, chlorates, chlorites, hypochlorites, chromates, dichromates and persulphates.
  • Alkali metal, such as sodium or potassium, salts may be especially preferred.
  • ORP oxidation-reduction potential
  • Use of solid oxidants may not allow the required ORP range to be rapidly attained so gaseous oxidants, which typically allow such rapid attainment, are to be preferred.
  • a further advantage that may accrue is better control over the leaching process as lag in attaining desired ORP, which is likely to be encountered with solid oxidants, may be avoided using gaseous oxidants. Both types of oxidant may be employed together with some advantage, if desired.
  • this may be introduced directly to the leaching stage via the leachant or feed, optionally in the form of an aqueous solution.
  • ferrous ions may be used than iron minerals present within the uranium ore.
  • iron or iron compounds may be added to the leach solution though this may be found uneconomic and it is therefore preferred that sufficient iron to practice the process is available within the ore to be treated.
  • Figure 1 illustrates a flowsheet for an acid leaching process for the extraction of uranium
  • a uranium ore comprising, for example, uraninite (having a theoretical formula U0 2 ) is transported from the pit to a primary gyratory crusher from which ore to be treated is recovered after screening as undersize and is stored in a fine ore bin. The oversize ore is recycled to the crushing step.
  • uraninite having a theoretical formula U0 2
  • Leaching takes place in tanks where the ore is agitated with sulphuric acid and an oxidant in the presence of an adsorbent catalytic agent which catalyses the oxidation of ferrous ions formed by acid attack on iron mineral(s) present in the ore, iron compounds available in the leach solution or iron introduced by the grinding media to ferric ions which oxidise the uranium (IV) oxide to the hexavalent uranyl cation (U0 2 2+ ) which is soluble in acid solution.
  • an adsorbent catalytic agent which catalyses the oxidation of ferrous ions formed by acid attack on iron mineral(s) present in the ore, iron compounds available in the leach solution or iron introduced by the grinding media to ferric ions which oxidise the uranium (IV) oxide to the hexavalent uranyl cation (U0 2 2+ ) which is soluble in acid solution.
  • the oxidant is manganese dioxide in pure or mineral (pyrolusite) form. Otherwise the oxidant generally employed is sodium chlorate. Air or oxygen have not been employed as oxidants because their slow rates of dissolution in acid solution prevent a substantial degree of oxidation of ferrous to ferric ions and hence oxidation of uranium (IV) to uranium (VI). This situation may be changed in accordance with the inventive process by addition of a catalytic adsorbent agent, conveniently activated carbon, though any resin or adsorbent having sufficient reactivity may also be employed.
  • adsorbent catalytic agent in an appropriate quantum, catalyses oxidation of ferrous ions to ferric ions by enabling a sufficient rate of availability in acid solution of oxygen sourced from oxidants as above discussed and particularly oxidising gases such as air, oxygen, ozone, elemental oxygen containing gases or mixtures of these gases that an oxidation reduction potential of at least +300 mV is attained in the acid leaching process and economically viable uranium extraction rates are obtained.
  • the most desirable quantum of activated carbon addition appears to be 10 to 200 g C/kg ore, preferably 14 to 70 g/kg ore, but other additions may be suitable depending on ore type and plant operating conditions. Other kinds of adsorbents may require to be added in different amounts.
  • pH a range of 0.7 to 2 is preferable. Below pH 0.7 carbon may be degraded. Above pH 2, base metals such as copper, lead and zinc; and silica dissolve, possibly with adverse effects.
  • the temperature may be maintained, with acceptable extraction, at 30°C or even lower. Heating to higher temperatures, especially say 60°C or above, in the leach tanks by addition of live steam or use of other heating arrangements may be employed to achieve even more favourable kinetics.
  • a further advantage that may occur using the present process is that, using pyrolusite, manganese dioxide or sodium chlorate, there may occur a period during leaching in which there is no value in introducing these reagents. This period corresponds with the time when ferrous ions commence coming into solution as a result of acid attack of iron, pyrite or other iron containing minerals in the uranium ore. In this period, the effect of these metallic compound oxidants on oxidation of uranium (IV) is negligible and possibly counter-productive as they may react with components such as hydrogen sulphide and hydrogen evolved during the acid leach. Clearly, such reactions would cause excessive reagent consumption.
  • gaseous oxidants as particularly preferred in the present invention, are employed. Therefore, these gaseous oxidants can, in the presence of a catalyst, be introduced from commencement of the leach process thereby achieving a small degree of oxidation of uranium (IV) to uranium (VI) in a period where conventionally used metallic compound oxidants are ineffective. To this extent the catalytic oxidation reaction described above may proceed in parallel with direct oxidation of uranium (IV) but independently thereof.
  • the barren ore and adsorbent catalytic agent e.g activated carbon
  • the barren ore and adsorbent catalytic agent may be separated from the pregnant liquor. Conveniently, such separation is achieved by a multiple-stage counter-current decantation process employing several thickeners.
  • the underflow constituents barren ore and activated carbon are separated with the barren ore usually being neutralised and disposed of or recycled.
  • the activated carbon is recycled to the leaching stage though it may require regeneration or treatment to remove adsorbed species before recycle.
  • the overflow from the thickeners is clarified by sand filtration to ensure that suspended solids are prevented from entering the uranium recovery circuit.
  • the activated carbon may be retained in the leach tanks by screens with occasional regeneration as required. If appropriate, additional stripping stages to recover species adsorbed onto the activated carbon may be conducted.
  • activated carbon may be substituted by other catalytic agents such as ion exchange resins, if desired.
  • the clarification of pregnant liquor is especially relevant in the case of uranium recovery by solvent extraction or resin ion exchange.
  • resin ion exchange strong base anion exchange resins are used to adsorb anionic uranium complexes which exclude metal cations.
  • Solvent extraction is also used to treat clarified acid liquors.
  • the pregnant liquor is passed through a series of mixture/settler units in which the pregnant liquor is contacted with an organic solvent, as for example referred to in A.R. Burkin, "Extractive Metallurgy of Uranium", such as an amine being 5% Alamine 336 and 2% isodecanol.
  • An organic solvent as for example referred to in A.R. Burkin, "Extractive Metallurgy of Uranium", such as an amine being 5% Alamine 336 and 2% isodecanol.
  • the process there described involved four stages and enables recovery of a uranium strip liquor grading 3-4 g/
  • the precipitation reaction proceeds as follows:
  • a uranium-rich ore or concentrate which contains precious metals values such as gold or silver may also be treated.
  • an acid leaching stage would be preferred as the first stage of the process in which uranium is extracted.
  • a leaching e.g cyanidation process is employed to enable extraction or precious metals from the pulp obtained from acid leaching the ore or concentrate.
  • a leaching route is preferred to avoid formation of cobalticyanide ions which interfere with ion exchange recovery processes.
  • uraninite uranium oxide
  • uraninite uranium oxide
  • uraninite disseminated in haematite and sulphide minerals
  • coffinite and brannerite the latter minerals being regarded as generally refractory to leaching-was treated.
  • the complex brannerite [(U,Ca,Fe,Th,Y)(Ti I Fe) 2 ⁇ 6 ] is regarded as unleachable and silicate coffinite [U(Si0 4 ) ⁇ - x (OH) x ] dissolves only slowly with an estimated 33% uranium in this mineral estimated to be leachable. The occurrence of these minerals reduces the probable extractable uranium in the tailings to 65-70% of total uranium.
  • tailings were slurried, by agitation, in water to produce a slurry grading 50% by weight flotation tailings.
  • Sufficient sulphuric acid solution was then added to the pulp to achieve a pH of 1.5. Leaching took place at 30°C and 60°C, the temperature being maintained constant for the duration of the leaching process.
  • Oxygen was introduced to the leaching vessel through a single nozzle located just below the impeller. Ideally, oxygen or other gases are to be 10 introduced in fine dispersion through sparging or similar operation. Rate of addition may be controlled to achieve a desired ORP.

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

Abstract

Un procédé permet d'extraire de l'uranium d'un matériau qui en contient, par un processus de lixiviation catalysé par un agent catalytique. Dans un procédé où la dissolution d'un minerai d'uranium présent dans ce matériau survient grâce à l'action d'ions ferriques sur ce dernier, ces ions ferriques, et le rapport souhaité d'ions ferriques aux ions ferreux, s'obtiennent par l'oxydation catalysée d'ions ferreux formés pendant l'attaque de ce matériau par l'acide.
PCT/AU1995/000095 1994-02-25 1995-02-24 Procede d'extraction de l'uranium WO1995023240A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU17491/95A AU698136B2 (en) 1994-02-25 1995-02-24 A process for extraction of uranium

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AUPM4145A AUPM414594A0 (en) 1994-02-25 1994-02-25 A process for extraction of uranium
AUPM4145 1994-02-25

Publications (1)

Publication Number Publication Date
WO1995023240A1 true WO1995023240A1 (fr) 1995-08-31

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ID=3778761

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU1995/000095 WO1995023240A1 (fr) 1994-02-25 1995-02-24 Procede d'extraction de l'uranium

Country Status (5)

Country Link
AU (1) AUPM414594A0 (fr)
CA (1) CA2213628A1 (fr)
FR (1) FR2716683A1 (fr)
WO (1) WO1995023240A1 (fr)
ZA (1) ZA951571B (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997012070A1 (fr) * 1995-09-27 1997-04-03 Tioxide Australia Pty. Ltd. Procede et appareil d'extraction de metaux
AU711928B2 (en) * 1995-09-27 1999-10-21 Tioxide Australia Pty. Ltd. Process and apparatus for extracting metal
WO2014169325A1 (fr) * 2013-04-15 2014-10-23 Bhp Billiton Olympic Dam Corporation Pty Ltd Procédé de traitement de minerai
EA036364B1 (ru) * 2018-10-03 2020-10-30 Акционерное Общество "Национальная Атомная Компания "Казатомпром" Способ подземного выщелачивания урана

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU1010855A (en) * 1955-06-24 1956-04-26 J. Michal and Robert R. Porter ugene Recovery of unanium values from uranium-bearing raw materials
US3488162A (en) * 1967-10-20 1970-01-06 Adam E Sierzputowski Oxidative treatment of uranium ore prior to acid leach
AU8254275A (en) * 1974-06-28 1977-01-06 Cyprus Metallurgical Processes Corporation Oxidising metal sulfides to elemental sulfur
FR2432554A1 (fr) * 1978-08-01 1980-02-29 Pechiney Ugine Kuhlmann Uran Procede d'attaque de minerais uraniferes par une solution de bicarbonates et carbonates de potassium
US4402921A (en) * 1980-11-20 1983-09-06 Phillips Petroleum Company Ammonium carbonate and/or bicarbonate plus alkaline chlorate oxidant for recovery of uranium values

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2890933A (en) * 1951-11-02 1959-06-16 Eugene J Michal Recovery of uranium values from uranium bearing raw materials
GB8630316D0 (en) * 1986-12-18 1987-01-28 British Petroleum Co Plc Separation process

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU1010855A (en) * 1955-06-24 1956-04-26 J. Michal and Robert R. Porter ugene Recovery of unanium values from uranium-bearing raw materials
AU3539058A (en) * 1958-02-18 1958-08-21 Trico-Folberth Limited Improvements in pumps
US3488162A (en) * 1967-10-20 1970-01-06 Adam E Sierzputowski Oxidative treatment of uranium ore prior to acid leach
AU8254275A (en) * 1974-06-28 1977-01-06 Cyprus Metallurgical Processes Corporation Oxidising metal sulfides to elemental sulfur
FR2432554A1 (fr) * 1978-08-01 1980-02-29 Pechiney Ugine Kuhlmann Uran Procede d'attaque de minerais uraniferes par une solution de bicarbonates et carbonates de potassium
US4402921A (en) * 1980-11-20 1983-09-06 Phillips Petroleum Company Ammonium carbonate and/or bicarbonate plus alkaline chlorate oxidant for recovery of uranium values

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997012070A1 (fr) * 1995-09-27 1997-04-03 Tioxide Australia Pty. Ltd. Procede et appareil d'extraction de metaux
AU711928B2 (en) * 1995-09-27 1999-10-21 Tioxide Australia Pty. Ltd. Process and apparatus for extracting metal
WO2014169325A1 (fr) * 2013-04-15 2014-10-23 Bhp Billiton Olympic Dam Corporation Pty Ltd Procédé de traitement de minerai
EA036364B1 (ru) * 2018-10-03 2020-10-30 Акционерное Общество "Национальная Атомная Компания "Казатомпром" Способ подземного выщелачивания урана

Also Published As

Publication number Publication date
ZA951571B (en) 1996-01-04
FR2716683A1 (fr) 1995-09-01
AUPM414594A0 (en) 1994-03-24
CA2213628A1 (fr) 1995-08-31

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