Scandium Partitioning Experiments

Scandium is a transition metal that is commonly used in aluminum-based alloys to increase strength.  These scandium-aluminum alloys are used in a variety of applications from sports equipment, such as baseball bats, to military use in weapons. Scandium has also been used as an alternative energy source in the form of solid oxide fuel cells.  With the potential for scandium to be a widely used metal both as alloys and a fuel source, there is a need for increased scandium production.    

MiG-29 Russian fighter jet with scandium-aluminum parts. Image source.

Geochemically, scandium is generally lumped in with the REEs and is thought to behave in a similar manner.  Due to this behavior one could hypothesize that scandium should be present in REE deposits and could be produced from such deposits.  However, producing scandium isn’t that simple of a process.  While the concentration of scandium in the Earth’s crust is ~22 ppm and higher than that of lead and many of the REEs (Rudnick and Gao 2003), there are very few large deposits of scandium.  Most of the scandium is distributed in minor concentrations in a multitude of minerals throughout the Earth's crust.  As such, most scandium is produced as a byproduct of other mining processes, partially from the REE deposits but also uranium, apatite, and titanium deposits.  This production has been limited to a few localities around the world such as China and Russia, with scandium resources only recently being identified in countries like the United States.  Even so, the United States imports 100% of its scandium from China (USGS 2017).

2016 U.S. Net Import from USGS (2017)

This proposed work would focus on determining the geochemical behavior of scandium during ore forming processes and provide the mining industry with tools for scandium exploration.  In particular, this work would focus on scandium’s behavior during magmatic process related to ore formation.  To determine this behavior a series of experiments will be run under magmatic conditions (800°C and 100 MPa) in cold-seal pressure vessels to determine in what phases (likely ferromagnesian phases) scandium is compatible with and under what conditions scandium deposits are likely to form.  These experiments will involve measuring the distribution and concentrations of scandium in both crystalline phases and a coexisting melt to obtain partition coefficients for scandium between solid and liquid phases.  By using these partition coefficients, a model for how  scandium deposits form can be derived and used by exploration geologists.

Potential experimental design.

Some research has been conducted on scandium, scandium partitioning, and scandium distribution in mineral phases, though little work has been done on scandium in ore deposits.  Below is a list of related papers that provide entry level and background information on scandium geochemistry:

1. Eby, G. N., 1973, Scandium geochemistry of the Oka carbonatite complex, Oka, Quebec  American Mineralogist, v. 58, p. 819-825.
2. Glassley, W. E., and Piper, D. Z., 1978, Cobalt and scandium partitioning versus iron content for crystalline phases in ultramafic nodules: Earth and Planetary Science Letters, v. 39, no. 1, p. 173-178.
3. Shchekina, T. I., and Gramenitskii, E. N., 2008, Geochemistry of Sc in the magmatic process: Experimental evidence: Geochemistry International, v. 46, no. 4, p. 351-366, doi:10.1134/S0016702908040046.
4. Sisson, T. W., 1991, Pyroxene-high silica rhyolite trace element partition coefficients measured by ion microprobe: Geochimica et Cosmochimica Acta, v. 55, no. 6, p. 1575-1585, doi:10.1016/0016-7037(91)90129-S.
5. Tilling, R. I., Greenland, L. P., And Gottfried, D., 1969, Distribution of Scandium Between Coexisting Biotite and Hornblende in Igneous Rocks: Geological Society of America Bulletin, v. 80, no. 4, p. 651-668, doi:10.1130/0016-7606(1969)80[651:dosbcb]2.0.co;2.

Our laboratory has seen success running similar experiments on indium, gold, copper, and molybdenum and is thus capable of performing these experiments:

1. Frank, M. R., Simon, A. C., Pettke, T., Candela, P. A., and Piccoli, P. M., 2011, Gold and copper partitioning in magmatic-hydrothermal systems at 800 °C and 100 MPa: Geochimica et Cosmochimica Acta, v. 75, no. 9, p. 2470-2482, doi:10.1016/j.gca.2011.02.012.
2. Gion, A. M., Piccoli, P. M., and Candela, P. A., 2017, From Lab to Lode: Applications of Experimental Geochemistry to Mineral Exploration with Reference to Indium: Student Mineral Colloquium, Prospectors and Developers Association of Canada, Toronto, Canada.
3. Gion, A. M., Piccoli, P. M., Candela, P. A., and Nance, J. R., 2016a, Indium In Ferromagnesian Minerals: An Experimental Study: Geological Society of America Abstracts with Programs, v. 48, no. 7, doi: 10.1130/abs/2016AM-286546
4. Gion, A. M., Piccoli, P. M., Candela, P. A., and Nance, J. R., 2016b, Partitioning of Indium Between Biotite and Felsic Melts: Pan-American Current Research on Fluid Inclusions Conference, Columbia, Missouri.
5. Hollingsworth, J.W. , Piccoli, P. M., and Candela, P. A., 2017, Evaluation of volcanic rock as a source for indium in hydrothermal environments: Student Mineral Colloquium, Prospectors and Developers Association of Canada, Toronto, Canada.
6. Simon, A. C., Frank, M. R., Pettke, T., Candela, P. A., Piccoli, P. M., and Heinrich, C. A., 2005, Gold partitioning in melt-vapor-brine systems: Geochimica et Cosmochimica Acta, v. 69, no. 13, p. 3321-3335, doi:10.1016/j.gca.2005.01.028.
7. Simon, A. C., Pettke, T., Candela, P. A., Piccoli, P. M., and Heinrich, C. A., 2003, Experimental determination of Au solubility in rhyolite melt and magnetite: Constraints on magmatic Au budgets: American Mineralogist, v. 88, no. 11-12, p. 1644-1651, doi:10.2138/am-2003-11-1202.
8. Tattitch, B. C., Candela, P. A., Piccoli, P. M., and Bodnar, R. J., 2015, Copper partitioning between felsic melt and H2O–CO2 bearing saline fluids: Geochimica et Cosmochimica Acta, v. 148, p. 81-99, doi:10.1016/j.gca.2014.08.025.

Timeline: Two Year Plan

            First Year: Graduate Students perform bulk of experiments

            Second Year: Interpretation of experiments in relation to natural systems

 

Materials and Funds Needed:

            Starting Materials: Gold, Platinum, and Scandium

            Funds: Travel and conference money, instrument time, and stipends/benefits for graduate students

 

 

References

 

U.S. Geological Survey, 2017, Mineral commodity summaries 2017, U.S. Geological Survey, 202 p., 10.3133/70180197.

Rudnick, R. L., and Gao, S., 2003, 3.01 - Composition of the Continental Crust A2 - Holland, Heinrich D, in Turekian, K. K., ed., Treatise on Geochemistry: Oxford, Pergamon, p. 1-64