Feldspar/Quartz Separation Also by Froth Flotation

The Gonçalo deposit: a good example of a future sustainable lithium mine

Violeta Ramos1, Rui Sousa3, Alexandra Guedes1,2, Fernando Noronha1,2, Ana Botelho de Sousa3, Mário Machado Leite3, Reimar Seltmann4, Alla Dolgopolova4 1Institute of Earth Sciences, Pole Porto/2Department of Geosciences, Environment and Spatial Planning, Faculty of Sciences, University of Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal 3Laboratório Nacional de Energia e Geologia, Rua da Amieira, Apartado 1089, S. Mamede de Infesta, Portugal 4Natural History Museum, Department of Earth Sciences, CERCAMS, Cromwell Road, London SW7 5BD, UK [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]

PROJECT FAME LITHIUM PEGMATITES Flexible and Mobile Economic Processing Technologies • Lithium (Li) demand is increasing due to its use in batteries for electrical “Critical Raw Material” Resources vehicles, among others. Investigation of 5 European pilot mining sites • The main ores for Li are brines and crystalline rocks rich on Li silicate Economic potential of skarn, pegmatite and greisen minerals and/or Li phosphates. ore deposits • In Europe, there are some regions with good potential for Li ore production: • the most important deposits are in crystalline rocks (CR) (granite Improvement of processing technologies; pegmatites and greisens); Recover valuable materials (W, Li and Sn) from low • the most important Li minerals in CR are spodumene, lepidolite, grade and/or complex feedstock’s. zinnwaldite, petalite and amblygonite-montebrasite.

TECTONIC AND GEOLOGICAL SETTING MINERALOGY OF THE APLITE-PEGMATITE SILLS

Variscan granites • Pegmatite: lepidolite (>500 µm); albite, Li - muscovite, G1: Biotite granite quartz and K-feldspar as major minerals, and montebrasite, G2, G3, G4: Biotite-muscovite Aplite topaz, cassiterite, columbo-tantalite, beryl and zircon as granites Pegmatite minor minerals. Zinnwaldite (K,Li,Fe,Al(Al,Si3)O10(OH,F)2) Neoproterozoic metasediments formed as result of metasomatic alteration of the host biotite Granite

“Schist-Greywacke Complex” granite in contact with the Li-rich pegmatites (bands with 10

cm to 20 cm). Petalite is scarce and altered to kaolinite,

Mineralization inPortuguese flat-lying potential aplite areas-pegmatite in W and Sn mineralization sills ranging [1]. in thickness cookeite and illite/smectite. Open pit of Gonçalo mine. from a few cm to over 5m. • Aplite: lepidolite (<250 µm), albite, montebrasite and

Sills hosted in a synorogenic Variscan coarse-grained porphyritic biotite quartz as major minerals. Some muscovite, topaz, cassiterite granite (G1 - Beiras granite) aging 304.1 ± 3.9 Ma (Neiva and Ramos, and columbo-tantalite are also present.

2010). Regional faults NNE-SSW to N-S and ENE-WSW to WNW-ESE. Pegmatite Aplite Host Granite

Raw Ore SLIMES REMOVAL >0.8% Li O (10-15% mass loss) Feldspar 2 Flotation

Lepidolite These products can be Desliming Flotation re-combined to fulfill specific requirements of Crushing ceramic industry R Tailings High Content Quartz Product Grinding (Rod Mill) Mainly quartz and Feldspar Product E feldspar (non float) (Concentrate) S Lepidolite Concentrate Main commercial product Chemical Assays High Content Feldspar U % Quartz Product Product of about 4-5% Product Li O, suitable for the 2 Li2O 0.62 0.13 metallurgy of Li L SiO2 69.93 81.40 compounds Al2O3 18.67 11.35 T Fe2O3 0.15 0.08 Proposed Flowsheet for Gonçalo ore processing: LOI 1.45 0.53 S 1 – Lepidolite recovery by Froth Flotation; 2 – Feldspar/Quartz separation also by Froth Flotation. Conversion to mineralogical composition (%)

Guidelines: Lepidolite 7.98 1.13 • To upgrade the lepidolite concentrate, meeting the metallurgy needs to produce Li compounds; Quartz 24.40 48.55 • To foster zero waste production, complying with the standards of “green mining”; Albite 47.38 40.79 - In this case, slimes produced during the desliming stage are considered as the only final waste; Orthoclase 5.49 2.77 Kaolinite 7.47 2.53 - The challenge is to generate feldspar and quartz products that can be blended in different Muscovite 4.97 3.43 proportions to fulfil the needs of several segments of the ceramic industry.

CONCLUSIONS FUTURE WORK • Gonçalo deposit can be a good example of a sustainable lithium mine, reaching an • The metallurgy of the lepidolite concentrate from Gonçalo ore must be further almost zero waste production; investigated;

• The flotation of lepidolite can generate a high Li2O grade concentrate, suitable to be • The performance of feldspar-quartz separation by froth flotation should be enhanced directly applied in the metallurgy stage to produce lithium metal; to improve the quality of the generated products; • The feldspar/quartz separation would produce two commercial by-products. • The mineralogical composition of the slimes must be obtained to find out if it is possible to be applied as a by-product.

REFERENCES Neiva, A.M.R., Ramos, M.F. 2010. Geochemistry of granitic aplite-pegmatite sills and petrogenetic links with granites, Guarda-Belmonte area, Central Portugal. Eur. J. Mineral. 22, 837-854.

Project FAME has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 641650. The authors acknowledge the funding by COMPETE 2020 through the ICT project (UID/GEO/04683/2013) with POCI-01-0145 reference - FEDER-007690. This work was financed by the scholarship programme with the reference SFRH/BD/114764/2016 by FCT – Fundação para a Ciência e Tecnologia.