SUPPLY AND SUBSTITUTION OPTIONS FOR SELECTED CRITICAL RAW MATERIALS: COBALT, NIOBIUM, TUNGSTEN, YTTRIUM AND RARE EARTHS ELEMENTS

Full text

* Corresponding author:
Andreas Bartl
email: andreas.bartl@tuwien.ac.at
Detritus / Volume 03 - 2018 / pages 37-42
https://doi.org/10.31025/2611-4135/2018.13697
© 2018 Cisa Publisher. Open access article under CC BY-NC-ND license
SUPPLY AND SUBSTITUTION OPTIONS FOR SELECTED
CRITICAL RAW MATERIALS: COBALT, NIOBIUM, TUNGSTEN,
YTTRIUM AND RARE EARTHS ELEMENTS
Andreas Bartl *,1, Alan H. Tkaczyk 2, Alessia Amato 3, Francesca Beolchini 3, Vjaceslavs
Lapkovskis 4 and Martina Petranikova 5
1
Vienna University of Technology, Institute of Chemical, Environmental & Bioscience Engineering, Getreidemarkt 9/166,
1060 Vienna, Austria
2
University of Tartu, Institute of Physics, W. Ostwaldi Street 1, 50411 Tartu, Estonia
3
Polytechnic University of Marche, Department of Life and Environmental Sciences-DiSVA, via Brecce Bianche, 60131, Ancona, Italy
4
Riga Technical University, Lomonosova str 1A/1, 1019 Riga, Latvia
5
Chalmers University of Technology, Department of Chemistry and Chemical Engineering, Kemivägen 4, 421 96 Gothenburg, Sweden
1. INTRODUCTION
The availability of certain raw materials is crucial to
Europe’s economy (EC 2014). The COST Action CA15102,
Solutions for Critical Raw Materials (CRM) Under Extreme
Conditions (www.crm-extreme.eu), focuses on the sub-
stitution of CRMs in high value alloys and metal-matrix
composites used under extreme conditions of tempera-
ture, loading, friction, wear, corrosion, in energy, transpor-
tation and machinery manufacturing industries. Presently,
the European Commission identies 26 raw materials or
groups of raw materials of strategic importance; these
materials exhibit both a high supply risk and important
economic impact (EU 2017). The present communication
reviews the current situation for a subset of this list: cobalt,
niobium, tungsten, yttrium, and the rare earth elements
(REE). It is evident that a strategy should be developed for
the identied materials to close the loop and minimize the
demand for virgin resources.
2. STATE-OF-THE-ART
2.1 Cobalt
Cobalt (Co) belongs to group 9 of the periodic table.
The interest in Co is due to its industrially useful properties
including ductility, malleability and magnetizability. These
characteristics, combined with heat resistance (melting
point 1495°C and boiling point 2870°C) and strength, make
cobalt suitable for a wide variety of industrial and military
applications (Minerals UK 2009).
Co has been known since ancient times. The rst evi-
dence dates to 2600 B.C., when blue glazed pottery was
found in Egyptian tombs. Co-containing materials have
been used as pigments for decades. The pure metal was
isolated by Georg Brandt in 1735 (Donaldson and Beyers-
mann 2005).
The vast majority of Co is mined in Congo, which
accounted for 54% of mine production in 2016. Further-
more, about half of the global reserves of Co are estimated
to be in Congo. The importance of other countries is limit-
ed, with the individual share of other countries not exceed-
ing 6%. Table 1 gives an overview of the geographical dis-
tribution of Co mining and reserves.
Typically, Co is used for metallurgical applications, as
a component of superalloys, for the building of turbine
engines for aircrafts, in the chemical sector (catalysts,
adhesives, pigments, agriculture, and medicine), for the
ABSTRACT
European industry is dependent on the import of raw materials. The European Com-
mission has recognized that some raw materials are crucial for the function of the
European economy and show a high risk of supply shortage. This communication
addresses supply and substitution options for selected critical raw materials: cobalt,
niobium, tungsten, yttrium, and the rare earth elements. For each element, the most
relevant data concerning mining, abundance, recycling rates and possible substi-
tutes are summarized and discussed.
Article Info:
Received:
25 January 2018
Revised:
11 July 2018
Accepted:
22 August 2018
Available online:
10 September 2018
Keywords:
Circular economy
Recycling
Critical raw materials

A. Bartl et al. / DETRITUS / Volume 03 - 2018 / pages 37-4238
production of cemented carbides, and for the ceramics
and enamels industry (CDI 2006). Nevertheless, the most
common application is the manufacture of lithium-ion bat-
teries, used for the power supply of electronic equipment.
China is the leading consumer of cobalt, with nearly 80%
of its consumption being used by the rechargeable battery
industry (Shedd 2017a).
The recycling of Co is massively dependent on the appli-
cation. Co-containing alloys are reprocessed into similar
alloys and do not require a specic recycling technology.
Hardmetal scrap is commonly recovered within the metal
carbide sector. As lithium-ion batteries are the most com-
mon application, several recycling procedures have been
developed for this area. The process commonly starts with
reductive leaching (e.g. H2SO4, H2O2) followed by extraction
and cobalt precipitation (Chen et al 2011, Pagnanelli et al
2016, Jian et al 2012). Cobalt recycling from applications in
pigments, glass, paints, etc. is not readily possible as these
usages are dissipative (EU 2016).
Table 2 summarizes possible substitutes for Co. For
some applications, however, Co is essential as substitution
would lead to a loss of product performance. This is in par-
ticular the case for the application with the highest share,
lithium-ion batteries (25%). Even though intensive research
is being conducted in this area, a short-term breakthrough
cannot be expected (Nayak 2017).
Considering the many uses, the recent Co demand has
grown and it is essential to counteract the increased pro-
duction of waste with increased recovery efforts (Cheang
and Mohamed, 2016). According to EC 1014b, the end-of-
life recycling input rate in the European Union in 2014 was
16%. For the USA, a recycling rate of 32% was reported in
1998 (Shedd 2004). In a more recent document, howev-
er, the EU Commission estimates the end-of-life recycling
input rate to be zero (EC 2017).
2.2 Niobium
Niobium is a transition element of group 5. Due to its
properties, it belongs to the group of refractory metals
(Bauccio 1993). A Nb-containing oxide was rst described
by Charles Hatchett in 1801 who proposed the name
Columbium (Hatchett 1802). Due to its similar properties,
Nb could not be distinguished from Tantalum until 1865.
Even if the ofcial IUPAC name is Niobium (Nb), the name
Columbium (Cb) is still widely used in North America.
Nb reserves are virtually inexhaustible (Schulz and
Papp 2014), but are classied as critical due to the high
production and deposit concentration in Brazil, as shown
in Table3.
Ferroniobium is by far the most important application
for Nb and consumes almost 90% of the market (TIC 2016).
Ferroniobium itself is used almost exclusively as an alloy-
ing element for steels containing Nb. In particular steel
numbers starting with 1.45 or 1.46 may contain Nb, even if
the concentration is below 1% (DIN 2014). Other end-uses
are Nb chemicals, vacuum-grade Nb master alloys, pure Nb
metal and Nb alloys such as NbTi (TIC 2016).
Commonly, Nb is not recycled as pure element but
Nb-containing steels and superalloys are recycled for the
same alloy. Thus, Nb recycling is not a question of tech-
nology, but of logistics. According to Papp (2017), the
amount of recycled Nb is not available, but it may be as
high as 20%. However, other sources report recycling rate
of 56% (Birat and Sibley 2011). As Nb is used in relatively
low concentrations (<1%) in alloys (DIN 2014), separate
handling of Nb is often not worthwhile. Therefore, the ele-
ment is strongly diluted in iron scrap, where it no longer has
any function. Only recently, the European Commission has
claimed that the end-of-life recycling input rate is as low as
0.3% (EU 2017).
It is reported that Nb can be substituted by other mate-
rials, as summarized in Table 4. In any case, a loss of per-
formance or higher cost accompany the substitutes (Papp
2017). It should also be noted that the possible substitutes
themselves (e.g. W) are critical or mine production is much
lower than for Nb (e.g. Ta). Therefore, it is essential to rein-
troduce Nb into the product cycle. Demand for new ore
could be reduced through improved scrap management.
Mine production 2016 Estimated reserves
[t] Share [1000 t] Share
Congo 66,000 54% 3,400 49%
China 7,700 6% 80 1%
Canada 7,300 6% 270 4%
Russia 6,200 5% 250 4%
Australia 5,100 4% 1,000 14%
Zambia 4,600 4% 270 4%
Cuba 4,200 3% 500 7%
Philippines 3,500 3% 290 4%
Madagascar 3,300 3% 130 2%
New Caledonia 3,300 3% 64 1%
South Africa 3,000 2% 29 0%
United States 690 1% 21 0%
Other countries 8,300 7% 690 10%
World total (rounded) 123,000 7,000
TABLE 1: World Mine Production and estimated reserves of Co (Shedd 2017a).

39
A. Bartl et al. / DETRITUS / Volume 03 - 2018 / pages 37-42
Nb-containing steel grades should not be mixed with oth-
er steel grades, but rather should be remelted for similar
alloys.
2.3 Tungsten
Tungsten (W) has the highest melting point of the pure
metals and is irreplaceable in special industrial applica-
tions (BGS 2011). The name tungsten is derived from the
Swedish words tung (heavy) and sten (stone) and goes
back to Frederik Cronstedt, who described a high-densi-
ty mineral in 1757 (ITIA 2011). Juan José de D´Elhuyar is
considered to be the discoverer of tungsten. In 1783, he
reduced tungsten oxide with charcoal (ITIA 2011).
Cemented carbides, also known as hardmetals, are the
main use of tungsten and cover 56% of the market, followed
by steel/alloys (20%), mill products (17%) and others (7%)
(Somerley 2011). Other applications include catalysts, pig-
ments, lubricants, electronics and electrical applications,
solar power, medical and dental applications (Christian
et al. 2011). Special attention is paid to W applications in
materials under extreme conditions (Schubert et al. 2008).
As Table 5 shows, China is of paramount importance
for tungsten production. In 2016, the country accounted
for 82% of mine production. Vietnam, the second largest
producer, is lagging behind and has a share of 7%. No data
are available for the USA, but it has been reported that a
new tungsten mine was opened in northwest Utah in 2016
(Shedd 2017b). In 2016, however, 76% of the tungsten
imported into Europe came from Russia (EC 2014a).
According to Shedd (2011), the recycling rate for tung-
sten in the USA was 46% in 2000. A recent study (Zeiler et
al 2018) shows that on a global scale the end-of-life recy-
cling rate of tungsten (i.e. ratio of old scrap fed back) is
30% by 2016 and the recycling input rate (i.e. ratio of new
and old scrap fed back) is 35%.
Possibilities for W-containing waste materials are
described by Testa et al. (2014) and Shishkin et al. (2010),
for example. Potential substitutes for W are summarized in
Table6. In some applications, however, substitution would
lead to higher costs or loss of product performance (Shedd
2017b). Although depleted uranium or lead are not classi-
ed critical, their use is extremely problematic due to its
toxicity. It should also be noted that tungsten carbide has
unique properties which cannot be met by the suggest-
ed substitutes. For instance, Mohs harness of WC is 9.5,
while MoC lags far behind (5.5). It must be concluded that
tungsten is indispensable for certain applications at the
moment.
2.4 Yttrium
Yttrium (Y) is a transition metal but is also considered to
be a rare earth element (REE) along with scandium and the
lanthanoids (Connelly et al. 2005). Y is mainly consumed
in the form of high-purity oxide compounds for phosphors,
in ceramics, electronic devices, lasers, and metallurgical
applications (Gambogi 2016).
World production of Y came almost exclusively from
China, as Table 7 shows. Minor amounts of mine produc-
tion are reported for Brazil, India and Malaysia. However, the
estimated reserves are quite large (more than 0.5 Million t)
and far exceed mine production, which was estimated at
8,000 to 10,000 t in 2015 (Gambogi 2016). In contrast to
mine production, China’s dominance of global reserves is
less pronounced. As shown in Table 7, only 41% of reserves
are estimated in China followed by the USA, Australia and
India. The reserves of Y are linked to those of rare earths
(Gambogi 2016).
In many cases, Y is irreplaceable, as substitutes are
generally much less effective. Especially in electronics,
Application Possible substitutes
Magnets Barium or strontium ferrites, neodymium-iron-boron, nickel-iron alloys
Paints Cerium, iron, lead, manganese, vanadium
For curing unsaturated polyester resins Cobalt-iron-copper or iron-copper in diamond tools; copper-iron-manganese
Cutting and wear-resistant materials Iron, iron-cobalt-nickel, nickel, cermets, ceramics
Lithium-ion batteries; Iron-phosphorous, manganese, nickel-cobalt-aluminum, nickel-cobalt-manganese
Jet engines Nickel-based alloys, ceramics
Petroleum catalysts Nickel
Mine production 2016 Estimated reserves
[t] Share [1000 t] Share
Brazil 58,000 90% 4,100 95%
Canada 5,750 9% 200 5%
Other countries 570 1% n.a. n.a.
World total (rounded) 64,300 4,300
Application Possible substitutes
Alloying elements in high-strength
low-alloy steels
Molybdenum and vanadium
Alloying elements in stainless -
and high-strength steels
Tantalum and titanium
High-temperature applications Ceramics, molybdenum, tantalum,
and tungsten
TABLE 2: Possible substitutes for Co (Shedd 2017a).
TABLE 3: World Mine Production and estimated reserves of Nb (Papp 2017).
TABLE 4: Possible substitutes for Nb (Papp 2017).

A. Bartl et al. / DETRITUS / Volume 03 - 2018 / pages 37-4240
lasers, and phosphors, Y cannot be replaced by other ele-
ments. Yttrium oxide could be substituted by CaO or MgO
as stabilizer in zirconia ceramics, but a lower toughness
has to be accepted (Gambogi 2016).
Yttrium can be extracted from secondary resources
preferably by hydrometallurgical processes, as they are
also used for primary ores (Innocenzi 2014). Currently, no
large scale Y recycling facility is documented (UNEP 2011),
but progress is being made, including investigations into
the recovery of Y from at panel displays, spent optical
glass and ceramic dusts.
2.5 Rare Earth Elements
The rare earth elements (REE) comprise the group of
14 lanthanides, of which promethium exhibits the lowest
natural abundance. In addition to the 14 lanthanides, scan-
dium and yttrium also belong to the REE group (Connelly et
al. 2005), since these elements have chemical and physical
similarities with the lanthanides.
REE are considered to be of critical importance in sus-
Mine production 2016 Estimated reserves
[t] Share [1000 t] Share
China 71,000 82% 1,900 61%
Vietnam 6,000 7% 95 3%
Russia 2,600 3% 83 3%
Other countries 1,700 2% 680 22%
Canada 1,680 * 2%* 290 9%
Bolivia 1,400 2% n.a. n.a.
Austria 860 1% 10 0.3%
Spain 800 1% 32 1%
Rwanda 770 1% n.a. n.a.
United Kingdom 700 1% 51 2%
Portugal 570 1% 3 0.1%
United States n.a. n.a. n.a. n.a.
World total (rounded) 86,400 3,100
* Data for 2015
Application Possible substitutes
Cemented tungsten carbides Carbides based on molybdenum carbide and titanium carbide, ceramics, ceram-
ic-metallic composites (cermets), tool steel
Tungsten mill products Molybdenum
Tungsten steels Molybdenum steels
Lighting Carbon nanotube laments, induction technology, light-emitting diodes
Applications requiring high-density or the ability to shield radiation Depleted uranium or lead
Armor-piercing projectiles Depleted uranium alloys or hardened steel
Mine production 2011 Estimated reserves
[t] Share [1000 t] Share
China 8,800 99% 220 41%
India 55 0.6% 72 13%
Brazil 15 0.2% 2.2 0.41%
Malaysia 4 0.04% 13 2.4%
USA n.a. n.a. 120 22%
Australia n.a. n.a. 100 19%
Sri Lanka n.a. n.a. 0.24 0.04%
Other countries n.a. n.a. 17 3%
World total (rounded) 8,900 540
TABLE 5: World Mine Production and estimated reserves of W (Shedd 2017b).
TABLE 6: Possible substitutes for Co (Shedd 2017b).
TABLE 7: World Mine Production and estimated reserves of Y (Cordier 2012).

41
A. Bartl et al. / DETRITUS / Volume 03 - 2018 / pages 37-42
tainable applications. REE and their compounds also nd a
multitude of applications in various branches of industry.
Their demand is due to their use in various high-technol-
ogy applications, for example, phosphors for uorescent
lamps, high strength permanent magnets, metallurgy, and
applications in a number of green energy technologies.
The main applications of REE are catalysts, metallurgy,
magnets, electronics and in optical, medical, and nuclear
technologies (Long et al. 2010).
China plays a dominate role in the production of REE.
As shown in Table 8, China accounted 80% of mine produc-
tion in 2016, followed by Australia with an 11% share. Other
producers are of inferior importance. Global mine produc-
tion in 2016 was around 132,000 t.
REE are relatively abundant in the earth’s crust, and
there are signicant deposits outside China. Even if China
hold 80% of mine production, only 37% of the estimated
reserves are in China. Relevant deposits are located in
Brazil, Thailand, Russia and India. As summarized in Table
8, minor REE deposits are estimated in several other coun-
tries.
Despite their highly fragmented applications, viable
recycling technologies are already available today. In real-
ity, however, less than 1% of REE are currently returned to
the production cycle. (UNEP 2011, Tunsu et al. 2015). It is
estimated that improvements in recycling can be achieved,
particularly in the area of magnets, uorescent lamps, bat-
teries and catalysts (Jowitt 2018).
3. CONCLUSIONS
The present paper elucidates the availability, critical
nature, and analysis of production value chains and down-
stream processes of for selected critical elements: cobalt,
niobium, tungsten, yttrium, and the rare earth elements.
The European share of reserves and mine production
of these crucial elements is very low or even zero. Mine
production is often concentrated in a single or very few
countries. For Yttrium, 99% of mine production is in Chi-
na. As the selected elements are crucial for the European
industry, actions to reduce the dependency are strongly
encouraged. On the one hand, the COST Action CA15102
evaluates the possibilities of replacing these critical mate-
rials with common materials without signicant loss of
performance. On the other hand, the demand for critical
materials can be reduced by substituting new ores by sec-
ondary raw materials. It is evident that recycling needs to
be signicantly increased, as current recycling rates fall to
zero (e.g. for Co).
AKNOWLEDGEMENTS
This publication is based upon work from COST Action
CA15102 supported by COST (European Cooperation in
Science and Technology): “Solutions for Critical Raw Mate-
rials Under Extreme Conditions (CRM-EXTREME)”, Working
Group WG 4 – Value chain impact, www.crm-extreme.eu.
Furthermore, the authors would like to acknowledge net-
working support from COST CA15102.
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