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

Working Group 4 – Value chain impact Coming sooN (JOP): CRITICAL RAW MATERIALS UNDER EXTREME CONDITIONS: A REVIEW OF COBALT, NIOBIUM, TUNGSTEN AND RARE EARTH ELEMENTS

Criticality What is criticality? High supply risk accountability political stability and absence of violence government effectiveness regulatory quality rule of law High economic importance the proportion of each material associated with industrial megasectors such as construction, combined with its gross value added to EU GDP. This total is scaled according to total EU GDP to define the overall economic importance of a material. Source: EU Commission 2014

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) Close to zero (Hodecek 2017) 0.3 % (EU 2017)

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

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