rare earth metal extraction processes
DESCRIPTION
Amazing slides for Rare EarthTRANSCRIPT
A Review of the Mineral Processing
and Extractive Metallurgy of Rare
Monazite Bastnasite
and Extractive Metallurgy of Rare
Earth Minerals
Patrick R. Taylor
The Kroll Institute for Extractive Metallurgy
Colorado School of Mines
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Resource Recovery – Past & Present
Geology
Mining
Particulate
Education Engineering Economics Energy Environment
Waste Treatment, Processing & Minimization
Geology
Mining
Mineral Processing
Education Engineering Economics
PAST PRESENT
Particulate Materials Processing
Materials Chemical Processing
Materials Science & Engineering
Recycle
New Materials Development
Processing
Extractive (Chemical) Metallurgy
Physical Metallurgy
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US Potential ResourcesUS Potential Resources
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US Potential ResourcesOther Critical Materials
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US Potential ResourcesRare Earth Elements
• The rare earth metals include sixteen elements: yttrium (atomic number 39), lanthanum (57), cerium (58), praseodymium (59), neodymium (60), promethium (61), samarium (62), europium (63), gadolinium (64), terbium (65), dysprosium (66), holmium (67), erbium (68), thulium (69), ytterbium (70), and lutetium (71).
• The elements with atomic weights 57 to 71 are collectively called the lanthanides since they all have properties similar to lanthanum.
• Scandium (21) is sometimes included as a rare earth metal since it is chemically similar to yttri um and the lanthanides.
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US Potential ResourcesEnergy Critical Elements, American Physical Society & Materials Research Society, 2011.
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US Potential ResourcesUses
• One major use of rare earth metals is as catalysts in petroleum refining.
• They also have many metallurgical applications as pyrophoric alloys.
• Another application is the use of lanthanide • Another application is the use of lanthanide oxides as a constituent of high quality optical glass.
• The current high interest is due to rare earth applications (magnets) used in many new energy and defense applications and the Chinese control of supply.
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US Potential ResourcesRare Earth Markets
Catalyst5%
Glass2%Polishing4%
Metal Alloys14%
Ceramics4%
Others3%
Phosphors31%
Magnets37%
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US Potential ResourcesMinerals
• The two major minerals used as sources of rare earth metals are monazite (Ce-La-Nd-Prphosphate) and bastnasite (Ce-La-Nd-Prfluorcarbonate).
• Monazite is, or has been, mined in Australia, India, the United States, and other areas to a lesser degree.the United States, and other areas to a lesser degree.
• Bastnasite is primarily mined in the United States and China.
• Several other ores are mined for the rare earths as well, including xenotine, apatite, yttrofluorite, cerite, and gadolinite.
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US Potential Resources
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US Potential ResourcesUS Operations
• Rare earth mineral ores have been mined domestically by two companies at mines locations in California (bastnasite ore) and in Florida (monazite ore).
• The bastnasite mining was principally for the • The bastnasite mining was principally for the recovery of the rare earths.
• The monazite mining occurred in conjunction with the processing of heavy mineral sands for titanium and zirconium recovery.
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US Potential ResourcesMineral Processing
• Covert the as-mined ore into a product that may be marketed or treated further.
• This involves the removal of impurity compounds from the material being processed.
• For Rare Earths, this is complicated by the special operations required to separate the rare earths from each other (chemically).
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US Potential ResourcesMonazite
• In placer deposits, monazite may occur as a minor constituent along with sillimanite, garnet, and magnetite, while the major minerals are ilmenite, rutile, zircon and quartz.
• Other minerals that may occur in some locations are: cassiterite, chromite, picotite, baddeleyite, cinnabar, gold and platinum.baddeleyite, cinnabar, gold and platinum.
• Beach sand deposits may exhibit considerable variation and thus their flow sheets may be variable in detail.
• The next figure shows a general overview of beach sand processing.
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US Potential Resources
Example Flow Sheet – Mineral Processing –Gravity, Magnetic and – Electrostatic Separations
Some resources may be treated by utilizing the differences in properties properties (density, magnetic susceptibility, conductivity) of the minerals.
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US Potential ResourcesMonazite Ore Processing
• The ore undergoes grinding, spiraling, or other sim ilar operations for the initial coarse upgrading of the ore.
• Magnetic separation removes the magnetic ore constituents which can be processed separately or discarded as waste.
• The refined ore is then digested with sulfuric acid at 200-220oC.220 C.
• Rare earth sulfates and thorium sulfates are then dissolved and removed from the waste monazite solids by filtration.
• Rare earth elements are then precipitated as oxalat es or sulfates. These precipitates undergo separations to form rare earth oxides.
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US Potential ResourcesMineral Separations
• The separation of heavy minerals exploits small differences in specific gravity, magnetic susceptibility and surface ionization potential (conductivity). Monazite is typically the heaviest.
• Ilmenite, garnet, xenotime and monazite, in decreasing order of magnetizability, behave as magnetic minerals. Xenotime is more strongly magnetic than monazite.magnetic than monazite.
• In electrostatic separations, ilmenite and rutile a ct as conducting materials. Xenotime is a poor conductor and can be separated from ilmenite.
• Leucoxene can cause problems in the separation of monazite from ilmenite. A reduction roast of at 600 c converts the iron oxide in leucoxene into magnetite and enables easy separation.
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US Potential ResourcesExample Flow Sheet
Flow sheet uses gravity, magnetic and and electrostatic separation at different separation factors
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US Potential Resources• Bastnasite mining near Mountain Pass in southeastern California may be a the major source of rare earth metals in the U.S. again.
• The previous recovery process of the rare earths from this ore is shown in the following figure.
• The ore was initially crushed, ground, classified, and concentrated by flotation to increase the rare
BASTNASITE ORE PROCESSING
and concentrated by flotation to increase the rare earth concentrations from about 5% to about 60% (REO).
• The concentrated bastnasite undergoes an acid (HCl) digestion to produce several rare earth chlorides.
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• The resulting slurry is filtered and the solution is treated with sodium hydroxide to produce rare earth hydroxides.
BASTNASITE ORE PROCESSING
• This rare earth hydroxide cake is chlorinated, converting the hydroxides to chlorides.
• Final filtration and evaporation yields the solid rare earth chloride products.
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US Potential Resources
• 30-35% solids. Rougher flotation brings the grade from about 9% to 20% REO. Tails are 1-2% REO.
• Four stage cleaning is used – tailings are re circulated.
Mountain Pass Flotation
• The scavenger cons are reground and recirculated to roughers.
• After four stage cleaning, the final concentrate is thickened, filtered and dried
• The grade is 60% REO and the recovery is 65-70%
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US Potential Resources
A very complex flow sheet that requires significant energy and
Example Flow Sheet – Mineral Processing – Flotation and Chemical Treatment
energy and chemicals. Research may lead to alternative surface chemistry and flotation processes.
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US Potential ResourcesSimplified Bastanasite
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US Potential ResourcesBayan Obo Ore
• Numerous minerals occur intimately intergrown in the rare earth Bayan Obo iron ore.
• In addition to REO, products include: magnetite, hematite, fluorite and niobium oxide.
• Bulk flotation is carried out on 90% < 74 micron • Bulk flotation is carried out on 90% < 74 micron material with sodium carbonate to adjust pH, sodium silicate to depress iron and silicate minerals and a sodium salt of oxidized petroleum (paraffin soap) as collector.
• The flotation tailings are taken to iron and niobiu m recovery circuits.
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US Potential ResourcesBayan Obo Ore
• The cons are retreated after eliminating excess fatty acids and de sliming using sodium carbonate (pH 5-6), sodium silicate and sodium fluosilicate (depressants) and hydroxamic acid (collector).
• Rougher cons are 45% REO and has both • Rougher cons are 45% REO and has both monazite and bastnasite. Recovery is about 80%.
• Final treatment by cleaning or high intensity magnetic separation gives two fractions – a primary 68%REO concentrate and a secondary monazite concentrate (36% REO), with respective recoveries of 25% and 36% - 61% total.
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US Potential ResourcesExtraction of REO from Bastnasite
Once a concentrate is obtained, then the metals of interest must be extracted from the material. Several approaches are possible, usually involving calcining involving calcining and acid leaching.
The solutions are then subjected to ion exchange or solvent extraction for purification.
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US Potential Resources• The sulfuric acid method has been used
extensively in the US.
• Thorium and rare earths may be selectively, or totally, extracted depending on the conditions.
• The processes available are shown in the
Monazite Acid Treatment
• The processes available are shown in the following figure.
• Rare earth recovery is based on double sulfate precipitation.
• Yttrium and the heavy rare earths are very soluble and go along with thorium.
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US Potential ResourcesMonazite Acid Treatment
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US Potential ResourcesAlkali Treatment of Monazite
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• The rare earth hydroxides and chlorides which are recovered from monazite and bastnasite, typically would undergo further processing to produce and recover individual rare earth metal compounds for a variety of applications.
Processing of the Products
• Several processes are used to produce rare earth fluorides, nitrates, carbonates, oxides, and pure metals.
• Processes used include fractional crystallization, fractional precipitation, solvent extraction, ion exchange, and reduction.
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• Using fractional crystallization, one or more rare earths in a mixture are precipitated by changing th e salt concentrations in solution through evaporation or temperature control.
• Fractional precipitation involves adding a precipitating agent to selectively remove a metal f rom
Separations Processing
precipitating agent to selectively remove a metal f rom solution.
• A vide variety of processes have been developed to recover specific rare earths by these two technique s.
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• Liquid-liquid solvent extractions are often performed to separate a mixture of rare earths from each other, i.e., tributyl phosphate, which selectively extracts one rare earth from the others .
• Several stages of extractions are needed to
Solvent Extraction
• Several stages of extractions are needed to separate each rare earth metal.
• Example extractants are shown in the next slide.
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• Ion exchange may be used to produce highly pure rare earths.
• Since the rare earths form trivalent cations (3 +), a cation exchange resin might be used.
• For separating a mixture of lanthanides, the resin is first flushed with a solution such as
Ion Exchange
resin is first flushed with a solution such as cupric sulfate to prepare the resin for ion Exchange.
• A solution containing the lanthanides is then passed over the ion exchange resin.
• The lanthanides displace the cation, in this case cupric, on the resin surface.
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• To separate individual rare earth elements, an element containing a complexing agent, such as ammonium ethylenediamine tetra acetic acid (NH4
+EDTA), is passed over the resin.
• The EDTA has a high affinity for rare earths, and
Ion Exchange
• The EDTA has a high affinity for rare earths, and the lanthanides are complexed with the EDTA and displaced by NH 4
+ on the resin.
• Each lanthanide has a different affinity for EDTA, and individual lanthanides can be separated and recovered as a result of these varying affinities.
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• High purity rare earth metals can be produced by the metallothermic reduction of rare earth halides. This process is used when high purity is required.
Metal Production
• After converting the rare earths into fluorides, they are reduced to the metallic state through contact with calcium or barium at high temperatures.
• Fused salt electrolysis is also used.
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• Rare earth oxides are the end products of mineral processing, leaching and separations. These oxides are extremely stable and their reduction is difficult.
• This is compounded by the metals’ melting points and vapor pressures.
• Conversion of the rare earth oxide to a halide and
Introduction to Reduction
• Conversion of the rare earth oxide to a halide and reduction of the halide is a useful approach.
• Fused salt electrolysis is also a useful approach. This would be most useful for the lower melting point rare earth metals.
• The preparation of a rare metal by forming an alloy and then recovered from the alloy is another potentially useful approach.
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• Every process has certain advantages and limitation s with respect to applicability to individual rare ea rths, purity of product, yield of the metal, batch size, operational convenience, economy and environment.
• In spite of their chemical similarity to their triv alent states, the rare earths do display considerable var iation in properties like melting point and vapor pressure .
Introduction to Reduction
in properties like melting point and vapor pressure .
• Another factor is the possibility of di-valency in some rare earth elements. This frustrates attempts to produce them by the usual chemical and electrolytic reduction processes.
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• Under nonstandard conditions, that are more typical of real processes, pure components are not typical, so the activities play a significant role in the reaction potential. Activities less tha n unity changes the Gibbs energy of the reaction and can lead to more favorable conditions.
• Methods would include: the formation of a metal
Introduction to Reduction
• Methods would include: the formation of a metal with a low boiling point and hence vaporizing in a metallothermic reaction, recovery of the reduced metal as an alloy, and trapping the compound formed by the reduction in a complex slag.
• Also, carbothermic reduction under vacuum may be an efficient reduction at high temperatures.
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• The metallothermic reduction reaction may be represented by the equation:
M(I)Xn + iM(II) = M(I) + iM(II)Xn/IWhere M(I) is the metal to be produced, X is the anion, and i,n are the stoichiometric coefficients.
Metallothermy
• Feasibility is determined by thermodynamics.
• Practicality is determined by melting point, boilin g point, vapor pressure, density, viscosity (for liqu id components), and characteristics such as chemical reactivity, and alloying behavior of the reactants and products.
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• These reactions are generally exothermic, and by suitable choice of reactants, materials and process conditions it has been possible to realize many of t he characteristics listed.
• The reactants in a powder form favors better contac t and once initiated a quicker reaction.
• If the heat generated during the reaction is suffic ient
Metallothermy
• If the heat generated during the reaction is suffic ient to raise the temperature of both slag and metal abo ve their melting points, and if they remain molten for a sufficient length of time, so that the denser metal settles by gravity with the immiscible (slag) layer on top, a metal ingot and solidified slag may be obtained.
• When the heat of reaction is insufficient, other ty pes of products can form.
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• If the reaction occurs but the slag does not melt, the metal is formed as a powder in the slag. The slag i s then leached away to obtain a metal powder.
• Metal in the form of powder can also form when the slag melts, if the melting point of the metal is ve ry high and the metal is not sintered; but may form a coalesced sponge. Metal is recovered by slag
Metallothermy
coalesced sponge. Metal is recovered by slag leaching or vacuum distillation.
• By suitable choice of reductants, reactors and reaction conditions, the metal can usually be obtained in the chosen form.
• Rare Earth metals have been obtained by metallothermic reduction in the form of ingot, sponge or powder.
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• Metal ingot has been obtained using metallothermic reduction of rare earth fluorides as well as some o f the chlorides using calcium as a reductant.
• Sponge of some rare earth metals have been produced from chlorides using lithium as the reductant.
• Rare metal powders have been obtained by reducing
Metallothermy
• Rare metal powders have been obtained by reducing oxides with calcium.
• Certain rare earth alloys can be directly produced in ingot, sponge or powder form, followed by vacuum distillation.
• Purity depends on the purity of the starting materials, pure oxides, anhydrous chlorides or fluorides, reductants and reaction steps
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• The preparation of rare earth chlorides for use as an intermediate for reduction has been accomplished through two routes: wet and dry.
• Wet: hydrated rare earth chlorides are produced by dissolving the rare earth oxide in HCl, evaporating to a syrup, and then cooled to form the hydrated
Preparation of Rare Earth Chlorides
to a syrup, and then cooled to form the hydrated chloride crystals.
• Dry: various methods are shown on the next slide, along with various reduction methods.
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Preparation and Reductionof Rare Earth Chlorides
These methods to reduce REOs is complicated by the stability of these oxides. This requires significant purification prior to
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purification prior to reduction or very complex refining schemes.
Research on new reduction and refining methods may lead to alternatives.
Gibbs Energy Minimization forDry Chlorides (1 Nd 2O3 + 2 C + 2.5Cl2)
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• The major impurity is oxygen, either unconverted oxide or oxychloride.
• Carbon may be an impurity in carbo-chlorination.
• Vacuum distillation and filtration are the two methods used for freeing the rare earth chlorides.
Purification of Rare Earth Chlorides
• Vacuum distillation and filtration are the two methods used for freeing the rare earth chlorides.
• Vacuum distillation depends on the vapor pressure of the chloride.
• A second distillation may be required.
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Chloride Reduction Processes
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• Calcium, in a dolomite lined steel bomb, has been used to reduce cerium trichloride.
• Additional heat was provided by using calcium iodide booster reaction.
• After completion, the slag was removed and the
Chloride Reduction
• After completion, the slag was removed and the metal vacuum melted to remove any excess calcium or calcium chloride slag.
• Purity was 98% and yield was 95%.
• Also used for lanthanum, praseodymium and neodymium.
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• Chloride reduction for the five metals (La, Ce, Pr, Nd and Gd) can not be applied to the higher melting point metals because of excess chloride volatilization and decreased yields.
• This can be overcome by making an alloy with a lower melting point metal.
Intermediate Alloy Process
• Yttrium metal as a yttrium -magnesium alloy by calcium reduction in the presence of Mg.
• Excess Ca and Mg were removed by vacuum heating.
• Also, Scandium metal reacted with calcium and/or magnesium
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• This would form a sponge.
• Lithium/sodium reaction of Yttrium chloride used a stainless steel vacuum retort in a glove box. Mo crucible.
Kroll Type Processes
crucible.
• Evacuated with vacuum and refilled with Ar.
• 850 C for one hour and 900 C for 16 hours to remove excess Li or Na and Li and Na chloride
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• Wet method – the oxides are dissolve in hydrochloric or nitric acid.
• The addition of aqueous HF to this solution results in the precipitation of hydrated fluorides.
• The product is dried at 100-150 and then heated to
Preparation of Rare Earth Fluorides
• The product is dried at 100-150 and then heated to 300 C in a vacuum or 600 C in a stream of anhydrous HF.
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Preparation and Reductionof Rare Earth Fluorides
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Gibbs Energy Minimizationwith Nd 2O3 + 6HF
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Reduction of Rare Earth Fluorides
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Gibbs Energy MinimizationCeF3 + 3Li = 3LiF + Ce
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Gibbs Energy MinimizationCalcium Reduction (2 NdF 3 + 3.3 Ca)
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• Rare earths form highly stable oxides. Only calcium forms an oxide that is more stable.
• The stability of Mg is only marginally higher than that of the heavy rare earth oxides and comparable to those of the light rare earths.
Oxide Reduction Processes
• The relative stability of MgO makes its use problematic.
• The high melting point of CaO (2600 C) is a disadvantage.
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• Similar to the Pidgeon Process for Mg can be used for samarium, europium and ytterbium (not obtained through halide routes).
• Vapor pressure measurements of the rare earth metals have indicated that lanthanum was the least volatile of the rare earths and that dysprosium had a vapor pressure nearly 300 times higher.
Reduction -Distillation - Lanthanothermy
higher.
• Samarium and europium are also very volatile.
• Lanthanum oxide has one of the highest (-) heats of formation among the rare earth oxides.
• This led to a process for reducing these oxides with lanthanum and volatizing the products.
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• Samarium and Ytterbium were prepared by heating the oxides with La in tantalum crucible at 1450 C and 0.1 Pa for one half hour.
• Europium was prepared by reaction with La in the
Lanthanothermy
reaction with La in the reactor shown.
• Heated to 1000 C at 0.02 Pa and then to 1100 and 1200 C.
• Samarium, if present, is not volatile.
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1.5
2.0File: C:\HSC5\Gibbs\GibbsIn.OGIkmol
La
Gibbs Energy MinimizationLanthanothermy (Tm 2O3 + 2.2 La)
0 500 1000 1500 20000.0
0.5
1.0
CTemperature
Tm2O3
Tm
La2O3
N2(g)Tm(g)
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• The metal product needs to have an appreciable vapor pressure while every things else has a negligible vapor pressure.
• Is some cases Cerium or Zirconium are used.
Other Reduction –Distillation
Zirconium are used.
• Samarium or europium oxides are mixed with (La, Ce or Zr) placed in a Mo container and placed in a vacuum retort.
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• Nd2O3 is reduced with calcium in a calcium chloride-sodium chloride melt at temperatures around 710-790 C.
• The product is dissolved in molten zinc, followed by vacuum distillation of the zinc.
• Neodymium oxide can not be reduced with Na; but
Other Reduction Processes
• Neodymium oxide can not be reduced with Na; but if CaCl 2 is added, then the sodium reacts with the CaCl2 to form Ca which can reduce the Nd 2O3 at 1100 C. Metal is dissolved in Zn or Fe.
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• Unlike the chemical reduction processes, electrolytic reduction does not rely on the availability of reducing agents and limited by the relative chemical stability.
• The Gibbs energy is related to the decomposition potential by:
• ∆∆∆∆Go = – nFEo
• It can be shown that an applied potential as small
Electrolysis Introduction
• It can be shown that an applied potential as small as 4 V should be adequate to dissociate even the most stable of compounds.
• This is only one of several requirements for effective methods to reduce stable rare earth compounds to metals.
• The process for electrolytic reduction of salts or compounds is basically simple.
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• The salt of a metal is dissolved in another salt or mixture of salts that are kept molten in an inert container.
• Two electrodes – a cathode and an anode – are inserted into the molten bath and an electric curre nt is passed through the circuit, with a voltage sufficient to reduce the salt.
Electrolysis Introduction
sufficient to reduce the salt.
• The molten salts (carrier electrolyte) serves as a solvent for the metallic salt to be reduced (functi onal electrolyte).
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• The carrier electrolyte is chosen to have a desira ble solubility of the functional electrolyte, sufficien t conductivity for the electric current, a melting po int below the desired operating temperature of the cell , low vapor pressure, and a greater stability than th e functional electrolyte.
Electrolysis Introduction
• These properties are normally obtained using an alkali or alkaline earth fluoride or chloride or a mixture of both.
• Considerable variability in cells used is seen: size , shape, materials of construction and disposition of the electrodes.
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• Iron, Graphite, ceramics such as fire brick and alumina, refractory metals such as molybdenum and tungsten have all been used as cell materials.
• The anode is usually made of graphite and the cathode is iron, molybdenum or tungsten.
Electrolysis Introduction
• Often the cell itself is the anode or cathode.
• Heat is supplied in two ways: the electrical curre nt to the cell is used to supply the necessary heat or an external furnace is used.
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• The largest amount of commercial rare earth metals are produced by electrolytic methods.
• La, Ce, Pr and Nd have melting points that permit recovery in the liquid state by electrolysis of relatively inexpensive chlorides at temperatures le ss than 1100 C.
• This facilitates metal slag separation, minimizes
Electrolysis Introduction
• This facilitates metal slag separation, minimizes contamination of the metal, and enables continuous operation and high volume levels of production.
• The technical feasibility of producing high melting point rare earth metals (Gd, Dy and Y) has been demonstrated by using fluorides in place of chlorides in specially designed high temperature cells.
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• The advantage of liquid metal recovery and low temperature operation have been realized even in the case of high melting point Rare Earth metals by using metals like: Cd, Mg, Zn, Mn, Cr and Co as cathode.
Electrolysis Introduction
cathode.
• These metals form liquid alloys with the rare earth metals as it electrodeposits and liquid product recovery is facilitated.
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Chloride Electrolysis
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Oxide -Fluoride Electrolysis
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Recovery as Alloys
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Refining is complex as well and may involve vacuum
Refining of rare earths
vacuum melting, vacuum distillation, zone refining etc.
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�Re-evaluate the current state of the technologyavailable for rare earth resource processing.
�Identify and do research on those aspects that could be improved utilizing new mineral processing, extractive metallurgy and metal refining technology .
�Address the ultimate disposition of problematic
What are the thrusts and requirements for a research program in this area?
�Address the ultimate disposition of problematic elements in the solid and aqueous discharge.
�Help developed a trained engineering work force to tackle the research, development and production aspects.
�Finally, keep in mind that economics is always the bottom line in any resource recovery operation.
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�Improved mineralogical methods for both initial design and improved plant operations (audits).
�Improved gravity separation devices (spirals, multi gravity, centrifugal concentrators, etc.)
Gravity – Magnetic – Electrostatic Separation Improvements
�Improved magnetic separators (Rare earth rolls, HGMS, WHIMS, etc.)
�Improved electrostatic separators.
�Improved fundamental models
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�Improved understanding of mineral surface chemistry.
�Column flotation.
�Improved instrumentation and control.
Improvements in Flotation Fundamentals and Equipment
�Improved instrumentation and control.
�Development of fundamental models for design and operation (JK SimMet, JK SimFlot, MinOCad, etc.) .
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Much of the current utilized extractive metallurgy technologyfor rare earth elements was developed many years ag o andthere have been several significant advancements in ourunderstanding of chemical processing methods for ex tractionand separation. Among these advancements have been :
�Excellent chemical thermodynamics screening methods using Gibbs energy minimization.
�Improved extraction methods based on increased unde rstanding
Extractive Metallurgy
�Improved extraction methods based on increased unde rstanding of chemical kinetics, reactor design and transport phenomena (heat, mass and momentum).
�Improved understanding of solution purification tec hniques, such as solvent extraction and ion exchange.
�Improved models and software for chemical reactor a nd flow sheet design.
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Much of the current technology used for rare earth metal reduction was developed many years ago. There have been several significant advancements in metal reduction and refining technology. Some of the more notable ones are:
�Excellent thermodynamics screening methods using Gi bbs Energy Minimization.
Metal Reduction and Refining
�Improved reduction and refining methods based on in creased understanding of chemical kinetics, reactor design and transport phenomena (heat, mass and momentum).
�Improved understanding of the electrochemistry in f used salt electrolysis
�Improved materials of construction to handle hot co rrosive systems
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Kroll Institute for Extractive MetallurgyKroll Institute for Extractive Metallurgy
Patrick R. TaylorDirector, KIEMG.S. Ansell DistinguishedProfessor of ChemicalMetallurgyEXPERTISE•Mineral Processing•Extractive Metallurgy•Recycling•Waste Treatment & Minimization•Thermal Plasma Processing
Brajendra MishraDirector, CR 3
Associate Director KIEM, Professor of Metallurgical and Materials EngineeringEXPERTISE•Pyrometallurgy•Electrochemistry•Materials synthesis•Waste Processing•Recycling•Molten Salt Processing
Corby G. AndersonHarrison Western Professor of Metallurgical and Materials Engineering
EXPERTISE•Extractive Metallurgy•Mineral Processing•Recycling• Waste Treatment & Minimization
Gerard P. MartinsProfessor of Metallurgical and Materials Engineering
EXPERTISE•Process and extraction metallurgy•Electrochemical systems•Transport phenomena•Reactor Design & kinetics
D. Erik SpillerResearch Professor of Metallurgical and Materials Engineering
EXPERTISE•Mineral Processing•Leaching•Project management: feasibility, engineering, construction management, operations
Paul B. QueneauAdjunct Professor of Metallurgical and Materials Engineering
EXPERTISE•Extractive and process metallurgy•Pyrometallurgy•Recycling•Waste treatment and minimization.
Judith C. GomezResearch Assistant Professor of Metallurgical and Materials Engineering
EXPERTISEExtractive and process metallurgyMaterials synthesisRecyclingWaste treatment and minimization
Edgar E. VidalResearch Associate Professor of Metallurgical and Materials Engineering
EXPERTISE•Extractive and process metallurgy•Pyrometallurgy•Recycling•Waste treatment and minimization.
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Industrial Projects - Current and Recent
� Magnetic separation of a vanadium containing titaniferrous magnetite;
� Beneficiation of iron ores (oolites);� Extraction of titanium from pickling
solutions;� Hydrogen sulphide sequestration;� Aluminum dross treatment;� Methods for treatment of electronic
scrap for feed to a copper smelter;� CR3 – Beneficiation of Photovoltaic
� Development on a new laboratory scale mill for evaluating operational changes in milling operations
� Ion exchange separation technologies for PGMs
� 2 Industry funded projects on Rare Earth extractive metallurgy
� Column flotation of a scheelite ore for improved recoveries and grades;
� Ammonium carbonate leaching of a � CR3 – Beneficiation of Photovoltaic (and other) Functional Coatings
� CR3 – Recovery of Rare Earth Metals from Phosphor Dust
� CR3 - Recycling of Bag-house Dust from Foundry Sand
� On-line diagnostic leaching of gold� Autoclave oxidation of Enargite;
� Ammonium carbonate leaching of a copper-zinc oxide ore;
� Bacterial oxidation in the presence of chloride ion;
� Selective flotation of elemental sulfur from sulfides;
� Development of an improved method for measuring and predicting abrasive wear in milling operation
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�Offer senior/graduate level (full or short) courses in mineral processing-extractive metallurgy-recycling–waste minimization in the evening, by web or video, or on-site.
�Develop engineering talent for future employment.
What KIEM can do for the mining and rare earth industry
�Encourage and market opportunities in industry to our undergraduate and graduate students.
�Perform research in support of industry goals.
�Maintain at least one significant program in the US with an emphasis on mineral processing-extractive metallurgy.
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Primary References
• “Extractive Metallurgy of Rare Earths”, C.K.
Gupta and N. Krishnamurthy, CRC Press, 2006
• Various technical publications and patents
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The Kroll Institute for Extractive MetallurgyThe Kroll Institute for Extractive MetallurgyGeorge S. Ansell Department of Metallurgical and Ma terials EngineeringGeorge S. Ansell Department of Metallurgical and Ma terials EngineeringColorado School of MinesColorado School of Mineswww.mines.eduwww.mines.edu
Hill Hall, home of KIEMHill Hall, home of KIEMPlease come see what we’re up to.Please come see what we’re up to.
THANK YOU.THANK YOU.
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