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Production of Scandium compounds and Scandium Aluminum alloys from European metallurgical by- products

Periodic Reporting for period 2 - SCALE (Production of Scandium compounds and Scandium Aluminum alloys from European metallurgical by- products)

Reporting period: 2018-06-01 to 2019-11-30

Scandium (Sc) is one of the highest valued elements in the periodic table and a critical raw material for EC. Sc technological applications are unique, as it is a key component in producing Solid Oxide Fuel Cells and high strength Aluminium alloys used in aerospace and 3D printing. Yet Sc supply is limited due to its scarcity and the high cost of its production, which currently takes place in Asia and Russia. Europe has no production of Sc, but is home to many Sc industrial end-users (Airbus, II-VI, KBM Affilips and others). In fact end-users like Airbus, are not deploying their Sc applications due to the lack of a secure Sc supply. The SCALE project sets about to develop and secure a European Sc supply chain through the development of technological innovations which will allow the extraction of Sc from European industrial residues. Bauxite Residues from alumina production and acid wastes from TiO2 pigment production have Sc concentrations which are considered exploitable, given a viable extraction technology.
The currently established Sc processing chain can be divided into three main blocks: Sc extraction from resources (where Sc is found at levels of mg/kg), Sc refining from g/kg concentrates to high purity compounds and Sc metal production technologies. The main barriers in this chain are found in the first and in the final block. Extracting from low-grade resources like BR and TiO2 acid waste is technologically complicated due to the nature of these resources; production of Sc metal and alloy is currently achieved only through a very expensive and small-scale technology. SCALE develops breakthrough technologies to overcome both extraction and metal production barriers, as well as optimizes refining technologies to reduce processing costs and remove use of harmful reagents.
The SCALE project objectives can be summarized as follows:
A. Produce commercial Sc concentrates from European metallurgical by-products at industrial pilot scale.
B. Refine Sc concentrates to Sc2O3 and ScF3 compounds.
C. Reduce Sc compounds to Sc metal and Al- Sc master alloys for end-user applications.
D. Assess the sustainability of developed technologies.
E. Promote the foundation a European Sc industry  
A. Extracting Sc from bauxite residue: Selective leaching against iron, aluminum and titanium has been achieved from the Greek BR which contains 100 to 130 ppm of Sc. Leach solutions (PLS) with 5 to 25 ppm Sc have been produced with different technologies. Resulting leach solutions with as low as 6 mg/lt in Sc have been utilized in the II-VI SIR process, to produce a concentrates with more than 60gr/kg Sc2O3 .
Extracting Sc from TiO2 acid waste: The acid stream from Tronox was tested first for nanofiltration (up-concentration of Sc content) and then for SIR extraction. Using self-developed membranes, up to 93% of Sc retention from the acid waste steam has been achieved using acid resistant nanofiltration at 5 bar pressure, with up to 12-fold higher Sc retention in comparison to Fe.The SIR has been tested successfully in lab scale with the TRONOX acid waste stream with a cumulative percent recovery of Sc up to 97%.
B. Novel and cost-effective flowsheet for Sc concentrate purification and Sc compound production: Separation of Sc by solvent extraction (99% Sc extraction efficiency achieved) followed by direct precipitation of Sc precursor from strip solution achieved using innovative anti-solvent crystallization techniques, producing up to 99 % pure compounds.
C. Sc metal and Al-Sc master alloy production:
• Aluminothermic production of Al- Sc master alloy from ScF3. Bulk Al-Sc alloys with contents up to 27 wt.-% Sc produced with no other impurities, at a Sc reduction yield of 77 %.
• Direct production of Al-Sc alloy from Sc2O3 was achieved in a cell setup used currently in the primary aluminium industry. Alloy obtained contained 2.6 wt% Sc at a current efficiency of ca. 85 %.
• Direct metallic Sc production from ScCl3 dissolved in an ionic liquid was achieved at 30 C electrolysis temperature with a 6 kWh/Kg total power consumption
D. Sustainability of SCALE technologies
-An initial benchmark for SCALE technologies has been established in frame of a LCA on traditional Sc2O3 production from REO deposits in China. The greenhouse gas (GHG) emissions of 1 kg Sc are between 9,500 and 14,600 kg CO2-eq.
-Initial results of the material flow analysis of a typical SCALE Sc production chain indicated that the production of 1 g Sc-metal requires ~ 340 kg bauxite residue. The proposed production chain covers all European Sc demand by European BR resources.
-International Reference Life Cycle Data (ILCD) indicators showed that human health risk and environmental risk (human toxicity and freshwater ecotoxicity) posed by the deposited BR, may be greatly mitigated by the SCALE technologies
E. European Sc sector development
-European Sc resources inventory: So far 40 different samples have been collected from European raw materials potentially suitable for Sc-recovery.
-In total the SCALE consortium has already generated 27 ‘dissemination results’, including its own website, which is constantly updated with news items relative to Sc. 
The SCALE project takes the first step in establishing the technological background needed to valorise European industrial by-products in Sc production. This will create a European Sc-supply outlet capable of covering both current and future Sc demand of European Sc end-users. Industrial uptake of SCALE technologies can lead to:
• Securing a Sc supply in Europe
• Reducing European import dependency significantly in REEs
• Improvements in metallurgical resource efficiency utilization.
• Developing technological innovations in order to recover valuable materials from low grade/complex resources
• Advancing the economic performance of the Sc production through technological innovations that shorten its processing chain.
With a secure Sc supply chain, Sc end-users will be able to deploy their applications, which at first will be limited to high-priced products in the aeronautics industry and the SOFC industry. However as more and more components of Al-Sc are used the demand of Scandium will begin to grow. Based on availability of supply (the annual BR production in MYTILINEOS could produce up to 70 tpa of Sc) and a significantly high operational margin, the European Sc industry will be in a position to increase supply to meet an increasing Sc demand. With further investments and larger processing facilities, Sc will be produced at larger volumes and at lower cost. The balance between rising supply and demand will gradually reduce Sc prices, which will further increase demand, as Al-Sc and Sc2O3 will become attractive for use in other sectors like automotive and especially Lightweight and Electric Vehicles, Corrosion Resistant Alloys for marine (Ship Construction) applications, Electronics (lighting, lasers, etc) and others. The expected escalating production of Sc, offers straightforward access on currently scarce Sc raw materials, looking forward to be applied in potential applications or unlock new ones. SCALE partners such as II-VI, LCM, KBM and others have vested interests in investing further in the deployment of the European Sc industry.
Scale Project description
Scale Sc infographic