There is a lot of reading in the white paper. I have selected the sections and passages of the report that interested me the most and believe what is included in this white paper sheds some light on CLQ's interest in Scandium going forward.
http://www.emcmetals.com/i/pdf/Scandium-White-PaperEMC-Website-June-2014-.pdf
General Scandium Applications
Principal uses for scandium are in solid oxide fuel cells (SOFC’s), high-strength aluminum alloys, high-intensity metal halide lamps, electronics, and laser research.
Solid Oxide Fuel Cells (SOFC’s) – Scandia can substitute for yttria as a stabilizing agent for the solid electrolyte (typically zirconia) in the fuel cell. The substitution allows reactions to occur at lower temperatures, extending the life of the components and increasing the power density of the unit.
Metallurgy - Scandium readily alloys with aluminum and modifies the grain structure of the combined metal, dramatically increasing strength without sacrificing corrosion resistance, while offering enhanced weldability---something typically lost in the alloying process of high performance aluminum alloys.
Ceramics - The addition of about 20% scandium carbide to titanium carbide results in a doubling of the hardness of the mixed Ti-Sc carbide, to about 50 GPa, second only to diamonds in hardness.
Electronics - Scandium is used in the preparation of the laser material Gd3Sc2Ga3O12, gadolinium scandium gallium garnet (GSGG). This garnet when doped with both Cr and Nd ions is said to be 3 1/2 times as efficient as the widely used Nd doped yttrium aluminum garnet laser. Ferrites and garnets containing scandium are used primarily in switches in computers. These magnetically controlled switches work by undulating light passing through the garnet and microwave equipment.
Lighting – Scandium is used in mercury vapor high-intensity lights to create natural light. Scandium has a broad emission spectrum that generates a ‘daylight’ effect desirable for camera lighting, movie and television studio lights.
Phosphorus/Displays - Scandium compounds have application as a host for phosphorus or as the activator ion in TV or computer monitors. Sc2O3 and ScVO4 are typical host materials, while ZnCdS2, activated with a mixture of silver and scandium, creates a red, luminescent phosphorus suitable for use in television displays. The current cost of scandium typically dictates the use of other materials in these applications.
One good ‘pointer’ for future scandium applications is the current usage of yttrium. Yttrium oxide (yttria) has a world supply/demand figure of about 11,000 tonnes and was again included on the critical metals list by the US DOE (2011). The US DOD put yttrium on it’s shortfall list in 2013, recommending stockpiling. Yttria is used as a dopant for other metals where extreme heat resistance is required, and its electrical conductivity makes it useful in SOFC’s and other applications. It is also a catalyst in chemical refining, and is used as a phosphor in energy-efficient lighting systems. Scandium has much better electrical conductivity than yttrium, is a superb heat-treating (and strengthening) dopant, and has known application in high performance lighting. While scandia is ~100 times the cost of yttria, scandia’s superior physical properties and attributes can outweigh the cost disadvantage in many applications. At this time, yttria has clear commercial acceptance over scandia in numerous applications because it is available in quantity (China supplies 90% globally).
Current Scandium Production
The USGS publishes a Minerals Commodity Summary on scandium, and it is of some value in determining true market volumes or prices. The most current USGS published price estimate for scandium oxide (2013) is US$5,000/kg for 99.99% grade, with considerably lower pricing estimates for lesser purities. Small quantities generally command higher prices on the internet. Global trade volumes are defined as ‘very small’, less than 10,000 kg (10 tonnes).
Various independent authors quote global market scandia volumes of 2-10 tonnes per year. EMC believes the current (2014) market supply is at least 15 tonnes per year. This estimate is based on discussions with potential customers, the level of metals trader activity and interest, and the fact that certain scandium consumers are believed to be sourcing their own scandium through small controlled recovery operations. This estimate doesn’t consider scandium contained in master alloy currently being sold from Russian stockpiles.
Current Market Opportunities for Scandium
Two robust growth markets await a reliable and expanded supply of scandium. These are defined as markets that would be able to utilize 2-5 times their current consumption, if only the supply sources were there to offer scandium at prices that could be absorbed into the product. In each case, the end product is a game-changer, and the cost of the new material comes with performance offsets that pay for the higher expense.
These two markets are:
1. Solid Oxide Fuel Cells (SOFC’s), and
2. Scandium-alloyed Aluminum alloys (Al-Sc alloys)
Solid Oxide Fuel Cells-Explained
In general terms, a fuel cell is an electrochemical cell that converts a fuel source and an oxygen source into an electrical current, plus water, CO2 and heat. It does this by promoting reactions between the fuel and oxidant (reactants), which are triggered by a very high temperature environment. SOFC’s employ a hard ceramic material as the solid electrolyte, sandwiched between an anode and a cathode, used to separate the reactants. At temperatures of approximately 1,000 ⁰C, two important changes occur in this system:
The solid ceramic electrolyte becomes ‘soft’, selectively porous, and electrically conductive, and
The reactant molecules in the system, kept separated by the solid electrolyte barrier, become highly ‘excited’.
In this excited state, oxygen molecules pick up electrons. This causes them to take on a negative charge becoming ions. The oxygen ions are then selectively drawn through the solid conducting electrolyte separating them from the hydrogen fuel source. Once through the electrolyte barrier, the oxygen combines with hydrogen (or hydrocarbon) molecules, to form water (or CO2) and heat. The extra electrons that enabled oxygen transport are thrown off in the combination with hydrogen. They are provided a direct return pathway to the cathode (+), generating a recurring flow of electrons which can be captured as electrical current. The reaction is exothermic, sustaining the proper high temperature reactive environment. The operation is continuous---as long as the reactants flow into the system, and the internal environment stays hot enough, the system generates current. There are no moving parts and no eroding parts, as exist in traditional batteries.
Fuel cells have been around for over a century, and were consistently employed by NASA as an electrical power supply source on spacecraft. There are a number of types of fuel cells, constructed with different architectures and different types of electrolytes, but the SOFC design is currently the clear leader. SOFC’s have distinct advantages in energy efficiency, flexibility with various fuel sources, lower exotic metal content, and low pollution levels.
High Efficiency. A SOFC running natural gas is approximately 60% efficient, which is about equal to the best of the combined cycle natural gas (CCGT) fired turbine generators used by pubic utilities. With heat recycle capability, SOFC efficiency can rise to over 85%. These efficiency levels represent the best currently achievable—coal or gas-fired facilities without heat recycling systems are typically 35% efficient, and internal combustion engines in automobiles are 25-30% efficient (gasoline/diesel).
Low Emissions. SOFC’s when operated with a hydrocarbon fuel source do generate CO2, but are much cleaner processors of fuels than combustion-based systems, and are considered low emission devices.
Localized Power. SOFC’s represent distributed power, which means they avoid both the transmission losses and most of the distribution infrastructure of traditional utility-provided electrical service. They can be placed where power is needed, subject to a fuel source. They initially generate DC power, so are particularly suited to sites with significant DC power needs, such as Data Centers.
Good Fuel Flexibility. SOFC’s are also the most fuel-flexible design because of their high operating temperature. High temperature allows SOFCs to reform fuels internally, which enables the use of a variety of fuels, and avoids the cost/complexity of adding a fuel reformer. SOFC’s tolerate several orders of magnitude more sulfur than other cell types, and are not poisoned by carbon monoxide (CO), which can even be used as a fuel. This property allows SOFCs to use gases made from coal.
While high operating temperatures enable many of the differentiating benefits of SOFC’s, they also tax the engineering and materials requirements needed for operation. Temperatures of 1,000⁰C create thermal fatigue in the system, rapidly oxidize metal components, and require expensive alloys and thermal shielding to retain heat and protect personnel. The solid electrolyte, typically zirconia, would never withstand this temperature without being stabilized with a metal. The stabilizing and conducting metal of choice for the electrolyte has traditionally been yttria (yttrium-stabilized zirconium, or ‘YSZ’), and it is often used in the anode and cathode metal mixture as well.
Enter scandium. Scandia is a better choice as the stabilizing agent for the zirconia (ScSZ) in the solid electrolyte because it is a considerably better ionic electrical conductor than yttrium. More importantly, scandium allows the electrolyte to conduct at significantly lower temperatures (750-800⁰C) and in fact raises the power density of the unit at those lower temperatures. This temperature drop is very significant in that it reduces the cost of materials for thermal shielding (stainless steel, rather than exotic
alloys) and it substantially reduces the thermal stresses within the unit. High temperature, yttria-stabilized SOFC’s (YSZ) typically exhibit a 2-3 year life, before requiring refurbishment/stack replacement. Scandia-stabilized SOFC’s are expected to achieve +10 year commercial operating cycles—although none have been in operation that long to say for sure. The dramatic increase in service life, along with greater power outputs and savings in other exotic materials and manufacture costs makes the economics of today’s leading edge SOFC’s competitive with grid-supplied electrical power. Today’s leading edge SOFC’s contain scandium.
There are over 100 companies working with, designing, or offering SOFC’s today. However, the technical leader in commercial SOFC technology is Bloom Energy, a private company headquartered in Sunnyvale, California. Bloom Energy ("Bloom") makes Bloom Energy Servers in 100KW and 200KW sizes, which operate typically on natural gas, can be installed in a commercial parking lot or garden area, and will generate electricity for 9-10 cents/kwh (Fuel Cell Maker Bloom Energy Opens The Kimono, Business Week, February 25, 2010). These units are in service, available for customers to purchase or lease, and enjoy certain US State/Federal energy-related tax incentives that further improve their economics. Bloom’s designs utilize scandium, and while scandia is currently 100 times the price of yttria, the overall operating parameter improvements are critical to the commercial competitiveness of the product. Bloom’s website is an excellent place to go to learn more on commercially available SOFC’s (www.BloomEnergy.com).
Aluminum-Scandium Alloys (Al-Sc)
In general, it is possible to modify and improve aluminum or titanium base materials by alloying them with scandium, typically by additions of up to 2% scandium (by weight). When scandium and aluminum metal are combined in a molten state, these two elements can be made to solidify in a number of different intermetallic phases, depending on the cooling temperature selected, and the Al-Sc ratio present. The most desirable of those phases (dispersoids) is as Al3Sc, which holds scandium in thermodynamic equilibrium with aluminum, and is the form that exhibits the most dramatic effects on the microstructure and properties of the resultant aluminum alloy material, which we will refer to as Al-Sc alloy.
The key changes are:
Grain Refinement – Scandium promotes (during so called heterogeneous nucleation) the formation of small, evenly shaped (equiaxed) grains in the alloy melt, which is a desirable characteristic. As a molten alloy metal mixture cools and solidifies, smaller evenly shaped grains are able to better fill the cavities created by the shrinking solidified metal. This creates increased strength by avoiding shrinkage porosity, and also reduces the tendency for hot cracking, which shows up in high temperature environments or as a result of welding. This grain refinement markedly improves both weldability and weld strength.
Superplasticity – This characteristic is defined as a substance’s ability to bend under stresses that would normally cause a fracture, and is typically achieved at half of the absolute melting point. Fine grained aluminum base material structure and stabilization of that grain boundary structure by the Al3Sc dispersoids is believed to cause this trait, which is highly useful in a manufacturing context. This allows alloy material to be heated and formed under high stress into more complex shapes without creating a narrowing or pinching which would otherwise lead to early fracture.
Precipitation Hardening –This is somewhat the opposite of the superplasticity characteristic, in that very fine and evenly distributed coherent Al3Sc phases, can give significant hardness increases to the alloy. These phases can be precipitated from a so- called supersaturated Al-matrix by moderate heat treatments of 250-350⁰C. All high performance (aerospace) aluminum alloys which display a strength value higher than 300 MPa (43 ksi) rely on precipitation hardening. This characteristic is particularly useful because the addition of scandium to certain Al-alloys (like 5XXX Al-Mg), that are otherwise not heat treatable, makes them respond to this beneficial annealing technique. Compared to other alloying elements, scandium is the most efficient precipitation hardener for aluminum base materials.
Beyond these micro-structure changes that occur when scandium alloys with aluminum, there are two other important and very practical application characteristics that emerge:
Corrosion Resistance - The addition of scandium to aluminum alloys makes them highly corrosion resistant. Aluminum resists corrosion by rapidly forming a thin oxidized layer which tends to halt further degradation, but salty environments can attack and destroy aluminum quickly. Typical aluminum alloying and hardening techniques tend to further reduce corrosion resistance. Scandium’s dramatic positive effect on corrosion resistance, in concert with increasing strength, is highly unusual and useful.
Weldability - Aluminum is weldable, as are many aluminum alloys, depending on their alloying components, and use of advanced welding technologies. With alloys however, the heat- affected zone at the weld site, particularly the frontier zone of the weld itself, tends to be weaker than the alloy base material---often by 50% or more. Some of this loss in strength can be regained by subsequent heat treatments, depending on the alloy specifics. Certain Al-Sc alloys weld with no appreciable loss in strength. This characteristic is extremely valuable, due to the flow-on effects of lower cost manufacturing options in designing and assembling aluminum alloy parts and structures.
There are several steps to the manufacture of Al-Sc alloys. First, the scandium oxide needs to be procured, which is the most significant problem today. The oxide grade is important but not critical: grades of 95% or better are suitable. Al-Sc master alloy typically has 2% Sc content, considerably above the first eutectic state, so most of the scandium is actually not fully dissolved in its inter-metallic form of
Al3Sc, as it is in the final product. The 2% master alloy is then used to precisely dose larger batches of molten aluminum, along with other desired alloying metals, to produce various aluminum alloys. Master alloy producers are typically smaller specialist companies who market a variety of master alloy products to the major aluminum smelters.
The science of advanced aluminum alloy manufacture is highly technical, and beyond the limits of this discussion. However, a couple more points are important to register, in terms of scandium’s potential to deliver a new, valued, high performance aluminum alloy to market:
A little bit of scandium makes a big difference. It doesn’t take much scandium mixed with aluminum to generate significant material improvements; as little as 0.10 - 0.15 wt-% Sc has dramatic effects, but more scandium tends to generate additional benefits, depending on the alloy processing route selected.
Higher scandium contents deliver more benefits. Scandium’s natural solubility in aluminum is about 0.4% (known as the first eutectic state), but the introduction of other alloy materials in combination with scandium, along with rapid-solidification techniques (like melt-spinning, powder atomization, and permanent mold casting technologies), can hold considerably higher concentrations of scandium properly in solid solution, enabling additional precipitation hardening by nano-sized Al3Sc dispersoids.
The technology of raising scandium content in alloys is advancing. The achievable amount of scandium in solid solution depends directly on the rapid solidification technology: the faster the solidification can be made to happen, the more scandium is taken up in the aluminum crystal lattice structure. As a general rule, 0.1 wt-% of Sc will provide about 50 MPa (8.5 ksi) of strength gain. Therefore 1.0 wt-% Sc can generate an additional 500 MPa (72.5 ksi) of tensile strength, and theoretically 2.0 wt-% could deliver an incredible 1,000 MPa (145 ksi) improvement. This strength level for an aluminum alloy would match that of a very high strength steel!
Al-Sc alloys also exhibit much higher heat working tolerances. Scandium raises the working heat range (due to micro structure stability) of aluminum by a factor of two, suggesting Al-Sc alloys could be employed in temperature environments of 350 -400⁰, which is appreciably higher than possible with other aluminum alloys.
Ultimately it is these strength improvements that engineers are seeking with the addition of scandium to aluminum alloys. Certain alloys show major strength improvement with solution heat treatment or other forms of hot or cold rolling, while others are not treatable in this manner. It is interesting to note that scandium’s strengthening improvement tends to be much larger (percentage-speaking) in the non-heat treatable alloys. Alloys that respond to strengthening procedures do also show further improvement by scandium additions, but those improvements are somewhat less dramatic.
These material technology efforts demonstrate dramatic improvements in strength and quality for future applications for scandium-modified aluminum alloys. The combined strength increases, corrosion resistance, and weldability, plus a unique fit to additive layer manufacturing (ALM) procedures have the potential to change the way many products and parts that are made from aluminum are designed and assembled. The flow-on manufacturing cost implications, the weight savings potential, and the longevity implications all feed back into the choice of the material for the application. The aluminum alloy industry is ready and waiting for substantial, reliable, and reasonably priced sources of scandium to be available in the market.
Market Pricing
There is no organized buy/sell market for scandium today. Scandium oxide (and metal) is not traded on a metals exchange, and there are no terminal or futures markets where buyers and sellers can fix an official price. Scandium product sells between private parties at undisclosed prices. Quotes for oxide product are influenced by product quality, volumes, availability, source, and of course demand. There are a number of internet-based traders offering scandium material for sale, but amounts on offer are generally small. The HEFA Rare Earth website is one of those sources that appears directly connected to a producer, Baotou HEFA Rare Earth, located in Baotou, China, sourcing products from the Bayan Obo mine in Inner Mongolia, China.
Scandium oxide prices are also influenced by quality, with 99.9% or higher grades representing the top quality, required for electrical applications, but not for alloy applications. The nature of the contaminants also matters---some are more problematic than others in specific applications. Radioactive elements, or metals that interfere with electrical applications in the case of SOFC’s, are particular problems. Quality discounts have greatly diminished lately, due to the current tight supply for any grade of oxide product, and the scarcity of the highest grade material.
Pure scandium metal is sometimes also available, but it is extremely scarce and expensive.
The 2014 USGS published price for scandium oxide (for 2013) is $5,000/kg, at 99.99% grade, slightly higher than for this grade in 2012. The price for 99.9% scandia in 2011 and 2012 was $3,700/kg, with no price published for this grade for 2013. The USGS published price now more accurately reflects actual trader offered prices, than pricing quoted prior to 2011. Availability is often an issue at any price, and quantities are small---from grams to 10 kg amounts. Large quantity (tonnes) pricing is not available, and no long term sales contracts are known to exist.
The 2014 USGS published price for aluminum-scandium master alloy (2% scandium) in 2013 is $170/kg, somewhat lower than the $220/kg price figure published for 2012.
Any significant user of scandium today would be required to produce product themselves, or contract for product to be produced from controlled stockpiles or industrial waste stream sources. Large volumes of scandia consumption are technically feasible in the future, with evident demand in several divergent markets and applications. That said, current quoted prices for scandia from the USGS or other sources remain much too high to enable widespread commercial adoption of scandium, in metals/alloy applications in particular. In order to see the various markets commit to larger scale scandia consumption, customers will look to see reliable supply sources, multiple supply sources, and cheaper scandia product than is available in today’s marketplace.