Journal Article

FZJ-2017-08126

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Lithium extraction from the mineral zinnwaldite: Part I: Effect of thermal treatment on properties and structure of zinnwaldite

Schneider, A. (Corresponding author) ; Schmidt, H. ; Meven, M.FZJ* ; Brendler, E. ; Kirchner, J. ; Martin, G. ; Bertau, M. ; Voigt, W.

2017
Elsevier Science Amsterdam [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.mineng.2017.05.006

Abstract: Lithium has become an energy critical element and thus the security of supply is of great importance. As a local German resource, attention was directed towards the mica-type mineral zinnwaldite. It represents a lithium-rich siderophyllite and corresponds to an intermediate polylithionite–siderophyllite solid solution with high contents of fluoride. Mineral samples from the deposit Zinnwald/Cínovec at the German/Czech border were analyzed and characterized by a variety of methods, particularly concerning its thermal behavior. Understanding the thermal behavior of the mica gives the opportunity to develop new and cost-efficient methods for lithium extraction.Investigations with different spectroscopic methods revealed the decomposition mechanisms. Starting at 300 °C, oxidation of Fe2+ catalyzed the dehydroxylation of the mica by dehydrogenation. This is followed by a dehydroxylation similar to the mechanism of dioctahedral micas. At higher temperatures, the release of HF was detected. At about 800 °C the precipitation of hematite was observed. The complete decomposition of Zinnwaldite takes place at 900 °C, it is accompanied by the liberation of SiF4 and leads to the formation of several solid decomposition products. By means of single-crystal diffraction using X-rays and neutrons the structural changes could be identified after annealing at 700 °C. The results point to a transformation into a polylithionite-like structure, the end member of the solid solution series.

Keyword(s): Earth, Environment and Cultural Heritage (1st) ; Crystallography (2nd) ; Geosciences (2nd)

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Contributing Institute(s):

1. JCNS-FRM-II (JCNS (München) ; Jülich Centre for Neutron Science JCNS (München) ; JCNS-FRM-II)
2. Streumethoden (JCNS-2)

Research Program(s):

1. 6G15 - FRM II / MLZ (POF3-6G15) (POF3-6G15)
2. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)
3. HITEC - Helmholtz Interdisciplinary Doctoral Training in Energy and Climate Research (HITEC) (HITEC-20170406) (HITEC-20170406)

Experiment(s):

1. HEiDi: Single crystal diffractometer on hot source (SR9b)

Appears in the scientific report 2017

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Database coverage:
Current Contents - Engineering, Computing and Technology ; Ebsco Academic Search ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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