Solvent Extraction Application in Non-Ferrous Metals Recovery - PowerPoint PPT Presentation

1 / 35
About This Presentation
Title:

Solvent Extraction Application in Non-Ferrous Metals Recovery

Description:

... chelating agent formula or structure extraction chemistry extractant class : chelating agent modifiers alcohols, phenols, esters (txib) ... – PowerPoint PPT presentation

Number of Views:1181
Avg rating:5.0/5.0
Slides: 36
Provided by: Rav145
Category:

less

Transcript and Presenter's Notes

Title: Solvent Extraction Application in Non-Ferrous Metals Recovery


1
Solvent Extraction Application in Non-Ferrous
Metals Recovery
SYMPOSIUM ON SOLVENT EXTRACTION REVISTED IIP
IIChE 05-06 FEBRUARY 2010 NEW DELHI
2
HYDROMETALLURGY
  • Hydrometallurgy is part of the field of
    extractive metallurgy involving the use of
    aqueous chemistry for the recovery of metals from
    ores, concentrates and recycled or residual
    materials. Hydrometallurgy is typically divided
    into three general areas
  • Leaching
  • Solution Concentration and Purification
  • Metal Recovery

3
LEACHING
  • Leaching involves the use of aqueous solutions
    containing a lixiviant ( liquid medium that
    selectively extracts the desired metal from the
    ore or material to be leached rapidly and
    completely and from which the desired metal can
    then be recovered in a concentrated form ) which
    is brought into contact with a material
    containing a valuable metal.
  • The lixiviant in solution may be acidic or basic
    in nature.
  • The type and concentration of the lixiviant is
    normally controlled to allow some degree of
    selectivity for the metal or metals that are to
    be recovered.
  • In the leaching process, oxidation potential,
    temperature, and pH of the solution are important
    parameters and are often manipulated to optimize
    dissolution of the desired metal component into
    the aqueous phase.

4
Solution Concentration And Purification
  • After leaching, the leach liquor must normally
    undergo concentration of the metal ions that are
    to be recovered by solvent extraction.
  • Additionally, some undesirable metals may have
    also reported into solution during the leach
    process.
  • The solution is often purified to eliminate the
    undesirable components. The processes employed
    for purification include
  • Precipitation
  • Cementation

5
Solvent Extraction
  • A mixture of an extractant in a diluent is used
    to extract a metal from one phase to another eg
    LIX 64.
  • In solvent extraction this mixture is often
    referred to as the "organic" because the main
    constituent (diluent) is some type of oil eg.
    Kerosene.
  • The PLS (pregnant leach solution) is mixed to
    promote contact with the stripped organic and
    allowed to separate in Mixer Settler.
  • The valuable metal will be exchanged from the PLS
    to the organic.
  • The resulting streams will be a loaded organic
    and a raffinate.

6
SOLVENT EXTRACTION - STRIPPING
  • Before electro-winning, the loaded organic is
    then mixed to promote contact with a lean
    electrolyte and allowed to separate in mixer
    settler
  • The metal will be exchanged from the organic to
    the lean electrolyte.
  • The resulting streams will be a stripped organic
    and a rich electrolyte.
  • The organic stream is recycled back to the
    solvent extraction section
  • Rich electrolyte is sent to Electro-winning
    section after filtering to arrest any entrained
    organic.

7
ELECTROWINNING
  • Electro-winning involves the recovery and
    purification of metals using electrodeposition of
    metals at the cathode.
  • The resulting products are metal cathode and
    lean electrolyte
  • The lean electrolyte is cooled and recycled back
    for stripping unit.
  • Metal cathode sheets are sent to for melting and
    casting

8
Application Of Solvent Extraction In Metals
  • The practice of hydrometallurgy contains examples
    of a great number of diverse solvent extraction
    processes.
  • Solvent extraction of metals such as copper,
    uranium, cobalt and nickel, besides being of
    great economic significance has been the spur for
    the development of the engineering aspects of
    solvent extraction
  • Besides the major metals there are commercial
    solvent extraction processes operated for the
    recovery of metals such as tungsten, rare-earths,
    thorium and vanadium.
  • Metals for which solvent extraction has
    succeeded and the circumstances, which caused
    these metals to become candidates for recovery by
    solvent extraction, have some common features

9
Application Of Solvent Extraction In Metals
  • They are soluble in suitable lixiviants such as
    sulphuric acid, ammonia and cyanide
  • They are relatively valuable. Copper, which is
    the lowest priced metal recovered in significant
    quantities by solvent extraction. Nickel, uranium
    and the precious metals are more valuable.
  • They can be recovered from the concentrated strip
    solution in a suitable marketable or intermediate
    form by processes such as electro-winning
  • Suitable solvent extraction chemistry has been
    developed and available for copper, nickel,
    uranium and other precious metals.

10
Application Of Solvent Extraction In Metals
  • Copper
  • Around 25 of the worlds copper is recovered
    using solvent extraction
  • The scope of solvent extraction for copper is
    only limited by the availability of acid
    leachable ore oxides.
  • Solvent extraction is considered to be the lowest
    cost production route for the production of
    quality cathode from low grade oxide ores.
  • Considerable attention is being directed towards
    development of suitable leaching techniques for
    chalcopyrite, the most ubiquitous of all copper
    minerals yet no commercial process is available.
  • Oxime based extractants took a giant step
    forward in 1974 when ZCCM commissioned their
    80,000 tonne per annum SX-EW plant at Nchanga

11
COPPER RECOVERY CURCUIT
12
Typical Flow-Sheet of SX/EW Plant
  • The Slide shows a typical flow-sheet of
    hydrometallurgical copper processing, which
    consists of three fundamental unit operations
  • Leaching of copper ore with a week acidic
    solution, which usually is sulfuric acid,
  • Solvent Extraction In which the aqueous pregnant
    leach solution (PLS) is vigorously mixed with an
    organic solvent, selectively recovers copper from
    PLS, being acidic or ammonia solution. The
    organic solvent is then separated and the copper
    stripped from it with a recycled lean electrolyte
    solution to produce a concentrated, relatively
    pure copper electrolyte suitable for the final
    stepelectrowinnig.
  • Eectrowinning Copper-rich solution is filtered
    to remove entrained organics, heated and then
    passed through a series of electrolytic cells to
    yeild high quality copper cathodes.

13
Major Copper Extractants
  • Developments of extractants based on
    hydroxyoximes were the key for copper solvent
    extraction.
  • The important issue for researchers has been an
    increase of extractant strength and consequently
    an improvement of stripping efficiency
  • The mixture, LIX64N, (blend of LIX 64 and LIX 63)
    extractant has been the popular choice for
    commercial copper extraction from acidic leach
    solution
  • Chelating hydroxyoxime extractants for copper

TYPE TRADE NAME
Ketoxime LIX 64
Ketoxime LIX 65N
Ketoxime LIX 84
Aldoxime Acorga P50
Aldoxime LIX 860
14
Application Of Solvent Extraction In Metals
  • NICKEL
  • In comparison to copper and uranium the
    percentage of the worlds nickel which is
    recovered using SX is relatively small
  • Today a number of Australasian laterite projects
    are developing nickel SX circuits which are in
    part based on the Queensland Nickel SX technology
  • PROCESS AND EXTRACTANTS
  • Sulphide nickel is usually treated using
    pyrometallurgical routes but in recent years
    there has been intensive activity in the
    development of hydrometallurgical routes for both
    sulphide concentrates and laterite ores
  • Nickel deposits may contain valuable quantities
    of cobalt and copper and these must also be
    recovered by SX if they are present in sufficient
    quantity.
  • There is a number of potential nickel extractants
    and circuit configurations

15
Application Of Solvent Extraction In Metal
  • CIRCUIT-1 Direct solvent extraction of copper,
    cobalt and nickel from acid leach solutions using
    oximes, phosphinic acids and versatic acids to
    extract copper, cobalt and nickel in sequence.
  • CIRCUIT-2. Matte leach chloride solutions may be
    purified by iron extraction with TBP followed by
    cobalt and copper co extraction as chloride
    complexes with tertiary amine.
  • Nickel does not form chloride complexes and
    remains in the raffinate. It may be recovered by
    crystallization and hydrogen reduction.
  • CIRCUIT-3 The base metals (Ni, Cu, Co, Zn) may be
    precipitated as hydroxides from sulphate leach
    solutions , re-dissolved in ammonia, the cobalt
    may be oxidised and the copper and nickel
    co-extracted with ketoxime
  • Of the above circuits, the ammonia leach circuit
    has received the greatest interest in the recent
    years for the recovery of nickel

16
NICKEL LATERITE ORE TREATMENT
17
Application Of Solvent Extraction In Metals
  • Uranium
  • The first metal to be recovered in significant
    quantities using solvent extraction was uranium.
  • In 1957 the first commercial solvent extraction
    plant using amines was opened in the USA.
  • Today most of the worlds uranium is recovered in
    hydrometallurgical circuits involving solvent
    extraction
  • Extractant used is Tertiary amines

18
Application Of Solvent Extraction In Metals
  • PRECIOUS METALS
  • Although the quantity of precious metals
    currently recovered using circuits that involve
    solvent extraction is small, the value of these
    metals is significant
  • Mintek, South Africa has developed a gold
    refining process based on solvent extraction and
    there exists a potential for gold recovery by
    solvent extraction
  • In the refining of platinum group elements
    solvent extraction plays an important role.

19
THE CHEMISTRY OF THE SOLVENT EXTRACTION OF THE
MAJOR METALS
  • Sudderth and Kordosky have given a useful
    classification of the four basic classes of metal
    extractants and have compared these extractant
    classes on the basis of structure, extraction
    chemistry and the metal species extracted
  • The four classes are
  • 1. Chelation Extractants
  • 2. Ion Pair Extractants
  • 3. Neutral or Solvating Extractants
  • 4. Organic Acid Extractants

20
EXTRACTANT CLASS CHELATING AGENT
FORMULA OR STRUCTURE
EXTRACTION CHEMISTRY
21
EXTRACTANT CLASS CHELATING AGENT
  •  MODIFIERS
  •  ALCOHOLS, PHENOLS, ESTERS (TXIB)
    KETOXIMES/ALDOXIME MIXTURES
  • SPECIAL FEATURES
  • Main commercial extractants for copper
  • Operate on hydrogen ion cycle. Stripping is
    reverse of extraction
  • Function with acid and ammoniacal leach solutions
  • More selective than other extractant classes
  • Kinetically slower than ion pair extractants
  • Have good physical properties in terms of phase
    separation, low aqueous solubility, chemical
    stability
  • Relatively expensive to manufacture

22
EXTRACTANT CLASS ION-PAIR EXTRACTANTS
  FORMULA OR STRUCTURE Quaternary Amines
R3RNCl- Primary Amines
RNH2 Secondary
Amines
R2NH Tertiary Amines
R3N     EXTRACTION CHEMISTRY
QUATERNARY AND Tertiary Amines  
23
EXTRACTANT CLASS ION-PAIR EXTRACTANTS
  • MODIFIERS I
  • SODECANOL OR TRIDECANOL, AROMATIC DILUENT
  •  
  • SPECIAL FEATURES
  • Commercial extractants for uranium, thorium,
    vanadium, gold, cobalt and other metals
  • Modifiers promote solubility of the extractant -
    metal complex in the diluents
  • Kinetics, both extraction and stripping are fast
  • Extraction is usually of a metal anion complex
  • Selectivity is not high. Other anions can
    compete with the metal being extracted
  • Tertiary amines are more selective than primary
    and secondary amines
  • Selectivity can be pH dependent
  • Primary, secondary and tertiary amines are
    relatively easy to produce

24
EXTRACTANT CLASS NEUTRAL OR SOLVATING
EXTRACTANTS
  • FORMULA OR STRUCTURE
  • Tri Octyl Phosphine Oxide(TOPO) R3P O
  • Tri Butyl Phosphate (TBP)
    (RO)3PO
  • Ketones (MIBK)
    R2CO
  • Alcohols
    ROH
  •   R CH3 and (CH3)2CHCH2
  • EXTRACTION CHEMISTRY
  • Extraction is by adduct formation
  • Stripping is with concentrated HNO3
  •  SPECIAL FEATURES
  • ? TBP is used extensively in nuclear fuel
    reprocessing
  • ? Kinetically fast
  • ? Extract neutral metal complexes
  • ? Selectivity is low
  • ? Organometallic complex must be organic soluble

25
EXTRACTANT CLASS ORGANIC ACID EXTRACTANTS
  • FORMULA OR STRUCTURE
  • Phosphinic Acids R3 P(O) OH
  • Sulphonic Acids R SO2OH
  • Carboxylic Acids R3C - COOH, Versatic
    Acid
  • Phosphoric Acids (C4H9CH(C2H5)CH2O)2 POOH,

    D2EHPA
  • SPECIAL FEATURES
  • Phosphinic acids are widely used for cobalt
    extraction
  • Versatic acids can be used for Cu and Ni
    extraction
  • D2EHPA extracts a wide range of metals
  • Operate on a hydrogen ion cycle but do not
    display hydrogen ion stoichiometry. Often between
    1 and 2 moles of extractant are required for each
    mole of hydrogen produced during extraction.
  • Selectivity is poor and careful pH control may be
    required to achieve reasonable selectivity

26
SOLVENT EXTRACTION- EXTRACTOR / EQUIPMENT S
  • For the major metals recovered by solvent
    extraction the mixer-settler contactor design
    predominates
  • There is a range of mixer settler designs
    available
  • In recent years there has been some attention
    refocused on the use of pulsed columns for plants
    using the kinetically fast ion- exchange
    extractants
  • Some features of mixer-settlers and columns are

27
MIXER SETTLER
  • Mixer Settlers
  • Well established with literally hundreds of
    operating units.
  • Design parameters are well established and very
    large units treating over 1000 cubic metres per
    hour of Pregnant leach solution can be designed
    from bench scale
  • Excellent mixing characteristics with control of
    the optimum droplet size claimed to be possible
    with modern turbine designs
  • Prediction of capital and operating costs is
    accurate.
  • The phases are readily accessible for sampling
    and examination in situ.
  • Several design varieties are available

28
MIXER-SETTLERS
29
COLUMN CONTACTORS
  • Column Contactors
  • Advantages claimed for the column contactor
    include
  •  
  • Low area requirements
  • Multiple stages within one unit
  • Few moving parts
  • Low entrainment
  • Good vapor conservation
  • Column installations require piloting for each
    installation and the flooding conditions for the
    column must be determined. Olympic Dam
    Corporation in South Australia has installed a
    large column plant for uranium extraction. The
    long residence times in a column compared to a
    mixer settler can influence the selectivity of
    the extraction if contaminants have slow
    extraction kinetics.

30
EIL EXPERIENCE IN SOLVENT EXTRACTION
  • Feasibility Reports on Heap Leaching for Solvent
    Extraction of Copper Oxide ores.
  • Scale up, Process package, Engineering and
    Setting up of Demonstration Pilot plant for
    recovery of copper, nickel and cobalt values from
    Poly Metallic Ocean Nodules (PMN).
  • Plant successfully commissioned in 2002 and
    Demonstrated the design values through number of
    test campaigns in 2003- 2004.

31
PMN PILOT PLANT
A VIEW OF SOLVENT EXTRACTION AND ELECTROWINNING
CIRCUIT AT PMN PILOT PLANT
32
EIL EXPERIENCE IN SOLVENT EXTRACTION PMN
  • The leaching of ocean nodules was done by IMMT
    (RRL-B) developed process- AMMONIA SO2 Leach
    Route
  • Metals like copper, nickel, cobalt and zinc were
    solubalised as their amine complexes leaving iron
    and manganese as residues.
  • Major portion of copper recovered using LIX 84 as
    extractant
  • The raffinate from copper extraction was
    subjected to sulphide precipitation
  • Bulk sulphide precipitate, on sulphuric acid
    leaching generated the leach liquor for further
    solvent extraction to recover the nickel and
    cobalt by a BARC developed three steps process.

33
EIL EXPERIENCE IN SOLVENT EXTRACTION PMN
  • In the first step , the impurity metals (copper,
    zinc and iron) were removed by extraction with
    partially saponified 0.5M D2EHPA and 5
    isodecanol in kerosene.
  • In the second step cobalt was extracted by PC88A
    from the raffinate solution coming out of first
    step containing cobalt and nickel.
  • In the third step Nickel was extracted by
    partially saponified D2EHPA from the raffinate
    of second step
  • The process was successfully demonstrated at
    specially set-up PMN Pilot Plant at HZL
  • The PMN Plant also had EW circuit
  • All the three metals were successfully recovered
    in the form of Cathode Sheets

34
METAL CATHODE SHEETS
NICKEL, COBALT AND COPPER CATHODE SHEETS
SUCCESSFULLY PRODUCED AT PMN PILOT PLANT
35
Thank You
Write a Comment
User Comments (0)
About PowerShow.com