Critical Raw Materials Under Extreme Conditions: A Review of Cobalt, Niobium, Tungsten, Yttrium, and Rare Earth Elements Andreas Bartl TU Wien, Institute of Chemical, Environmental & Biological Engineering Alan Tkaczyk University of Tartu, Institute of Physics Alessia Amato, Francesca Beolchini Polytechnic University of Marche, Department of Life and Environmental Sciences-DiSVA Vjaceslavs Lapkovskis Riga Technical University Martina Petranikova Chalmers University of Technology, Department of Chemistry and Chemical Engineering

Working Group 4 – Value chain impact https://www.crm-extreme.eu/ http://www.cost.eu/COST_Actions/ca/CA15102 29 Countries partners 171 Researchers Working Group 4 – Value chain impact

Criticality What is criticality? High supply risk High economic importance Source: EU Commission 2014, 2017

Criticality Source: EU Commission 2010

Criticality Criticality = scarcity? Concentration in earth crust Source: Rudnick & Gao (2003)

Niobium Facts Classification History Element of group 5 Belongs to the group of refractory metals History Discovered in 1801 by Charles Hatchett (Columbium) 1802: Anders Ekeberg: Tantalum 1809: William Wollaston: Tantalum = Columbium 1844: Heinrich Rose: New element: Niobium 1865: Identities resolved Niobium = Columbium Tantalum own element North America: Columbium (Cb) still used Source: Hatchet 1802, Ekeberg 1802, Rose 1844, Deville & Troost 1865, Hermann 1865

Major Minerals Columbite-tantalite group Pyrochlore group General formula: AM2O6 A = Fe, Mn, Mg / M = Nb (columbite), Ta (tantalite) Pyrochlore group General formula: A2‑mB2O6(O,OH,F)1‑n·pH2O B = Nb, Ti and/or Ta Nb and Ta more or less always comingled not only separate foreign elements but also Nb and Ta Source: Cerny & Ercit 1989, Crockett & Sutphin 1993, Hogarth 1977

Mine Production Mine production sharply increasing 2001 – 2007 (Threefold) Source: USGS 2017

Mine Production Geographic Distribution Brazil of major importance Approx. 64 year to depletion Estimated reserves [1000 t] Mine production in 2015 [t] Source: Papp 2017

Nb Reserves Nb is “hitchhiker” Bayan Obo mines in China Total of 1.5 Billion t of ore estimated 35 % Fe content Baosteel aims to produce 24 Million t of iron 70 Million t of ore mined annually Nb content is 0.13 % 89,000 t Nb as “hitchhiker” annually 1.4 times of Nb production is mined unintentionally Total Nb reserves: 1 Million t REE content is 6 % Source: Drew at al. 1991, Qi 2011

Prices Major price increase in the 2000s Source: USGS 2017

Uses Major markets for Niobium Source: TIC 2016

Uses Ferroniobium Master alloy of iron and niobium End use Alloying element For Cr , CrNi- or CrNiMo steel grades Steel numbers beginning with 1.45 and 1.46 Superalloys Source: ISO 5453 (1984)

Uses Nb bearing steel grades (Steel numbers beginning with 1.45 and 1.46) Steel number Short name Nb content 1.4509 X2CrTiNb18 (3 x C) + 0.30 % up to 1.00 % (C ≤ 0.03 %) 1.4511 X3CrNb17 12 x C up to 1.00 % (C ≤ 0.05 %) 1.4526 X6CrMoNb17-1 7 x (C + N) + 0.10 % up to 1.00 % (C ≤ 0.08 %; N ≤ 0.04 %) 1.4542 X5CrNiCuNb16-4 5 x C up to 0.70 % (C ≤ 0.07 %) 1.4550 X6CrNiNb18-10 10 x C up to 1.00 % (C ≤ 0.08 %) 1.4565 X2CrNiMnMoNbN25-18-5-4 up to 0.15 % 1.4580 X6CrNiMoNb17-12-2 10 x C up to 1.00 % (C ≤ 0.08 %) 1.4590 X2CrNbZr17 0.35 – 0.55 % 1.4595 X1CrNb15 0.20 – 0.60 % 1.4607 X2CrNbTi20 up to 1.00 % 1.4621 X2CrNbCu21 0.20 – 1.00 % 1.4634 X2CrAlSiNb18 Source: DIN EN 10088 (2014)

Uses Nb bearing superalloys Material number Short name Content  Nb + Ta Brands 2.4600 NiMo29Cr up to 0.40 % Nicrofer® 6629, Hastelloy® B-3 2.4619 NiCr22Mo7Cu up to 0.50 % Inconel® G-3 Nicrofer® 4823hMo 2.4660 NiCr20CuMo 8 x C up to 1.00 % (C ≤ 0.07 %) Nicrofer® 3620 Incoloy® alloy 20 2.4856 NiCr22Mo9Nb 3.15 – 4.15 % Inconel® 625, Nicrofer® 6020 2.4868 NiCr19Fe19Nb5Mo3 4.7 – 5.5 % Inconel® 718, Nicrofer® 5219 Source: DIN 17744 (2002)

Substitution Possible substitutes for Nb? Performance loss or higher costs may be unavoidable Substitute elements / materials Application Mo and V Alloying elements in high-strength low-alloy steels Ta and Ti Alloying elements in stainless- and high-strength steels Ceramics, Mo, Ta, and W High-temperature applications Source: USGS 2017

Recycling Substitute primary Nb by secondary Nb Focus: Alloys and superalloys (90 % of market) Recycling practice Nb not recovered as pure metal Separate collection of Nb bearing steel grades Re-melting Nb bearing steel scrap into the same alloy Recycling rates not available, up to 20 % (Papp 2017) 50 % (Cunningham 2004) 56 % (Birat & Sibley 2011) 11 % (EU 2014) Close to zero (Hodecek 2017) 0.3 % (EU 2017)

Recycling Recycling Ore (Columbite) Ferroniobium (FeNb65) Steel (e.g. 1.4511) Use phase (e.g cold end of automotive exhaust systems) Re-melting of Nb bearing steel Nb steel scrap

Conclusions Recycling (Functional / Non-functional) Ore (Columbite) Ferroniobium (FeNb65) Steel (e.g. 1.4511) Fe cycle Functional Recycling Non-Functional Recycling Use phase (e.g cold end of automotive exhaust systems) Re-melting of Nb bearing steel Nb steel scrap Steel scrap

Andreas Bartl andreas.bartl@tuwien.ac.at TU Wien Institute of Chemical, Environmental & Biological Engineering 1060 Vienna, Austria andreas.bartl@tuwien.ac.at The authors would like to acknowledge networking support by the COST action CA15102 “Solutions for Critical Raw Materials Under Extreme Conditions (CRM-EXTREME),” www.crm-extreme.eu.