TY - BOOK

T1 - Development of an Analytical Proof of Origin Method for Natural Graphite Deposits

AU - Dietrich, Valentina Elisa

N1 - no embargo

PY - 2024

Y1 - 2024

N2 - Graphite is considered as a critical raw material due to its essential role in various industrial applications, particularly in the steel, refractories and energy storage sectors. The latter, encompassing the production of lithium-ion batteries, is especially significant, as these batteries are essential to electric vehicles and numerous electronic devices. The escalating demand for lithium-ion batteries has consequently increased the demand for graphite and the interest in the provenance of this raw material. This thesis, as part of a larger initiative, focused on the traceability of graphite as an important battery raw material, aiming to enhance the transparency, reliability and sustainability of complex supply chains. The study introduces an innovative multi-parameter analytical approach to differentiate graphite concentrate samples from various global locations, including major graphite producing countries. Stable carbon isotopes serve as a primary parameter for distinguishing between carbon sources. Flake and amorphous graphite, originating from organic materials, contrast with hydrothermal graphite. Through this methodology, three distinct sample groups were identified: Ukraine, Sri Lanka and the rest of the world. The Raman spectrum, characterizing the microstructural state of graphite, provides information about the peak metamorphic temperatures during graphite formation and also allows a differentiation between different graphite types. However, the microstructure can be altered by mineral processing activities such as crushing and grinding, impacting the natural structure of the material. This technique enables the distinction of amorphous graphite from flake and hydrothermal graphite types. Trace element analysis potentially differentiates the origin of graphite on the most detailed, the deposit level. The geographic provenance of individual deposits can be traced through characteristic trace elements (including V, Mo, Cr, Co, Cu, Ga, As, Rb, Sr, Ba and REE patterns). Developing methods for solution-based analysis (such as ICP-MS) was necessary due to the inherent challenges in fully dissolving graphite, given the robust carbon layers. Laser Ablation-ICP-MS offers a less time- and cost-intensive method, though it also required significant method development for sample preparation and calibration. The ablation of very fine-grained compressed materials and the lack of reference and calibration materials presented notable challenges. A significant proportion of trace elements in graphite concentrates are associated with impurities and accompanying mineralogical components. These impurities can be identified and delineated through the application of advanced statistical methods and data processing techniques. Analytical proof of origin (APO) methods are considered incorruptible, as they directly relate to the chemical composition of the raw material, offering significant potential for verification and control purposes. Unlike methods such as documents, tracers, QR codes and barcodes, which can be manipulated or falsified, APO methods provide a robust means of authentication. The developed APO methodology serves to facilitate the implementation of supply chain laws and battery regulations within the graphite industry.

AB - Graphite is considered as a critical raw material due to its essential role in various industrial applications, particularly in the steel, refractories and energy storage sectors. The latter, encompassing the production of lithium-ion batteries, is especially significant, as these batteries are essential to electric vehicles and numerous electronic devices. The escalating demand for lithium-ion batteries has consequently increased the demand for graphite and the interest in the provenance of this raw material. This thesis, as part of a larger initiative, focused on the traceability of graphite as an important battery raw material, aiming to enhance the transparency, reliability and sustainability of complex supply chains. The study introduces an innovative multi-parameter analytical approach to differentiate graphite concentrate samples from various global locations, including major graphite producing countries. Stable carbon isotopes serve as a primary parameter for distinguishing between carbon sources. Flake and amorphous graphite, originating from organic materials, contrast with hydrothermal graphite. Through this methodology, three distinct sample groups were identified: Ukraine, Sri Lanka and the rest of the world. The Raman spectrum, characterizing the microstructural state of graphite, provides information about the peak metamorphic temperatures during graphite formation and also allows a differentiation between different graphite types. However, the microstructure can be altered by mineral processing activities such as crushing and grinding, impacting the natural structure of the material. This technique enables the distinction of amorphous graphite from flake and hydrothermal graphite types. Trace element analysis potentially differentiates the origin of graphite on the most detailed, the deposit level. The geographic provenance of individual deposits can be traced through characteristic trace elements (including V, Mo, Cr, Co, Cu, Ga, As, Rb, Sr, Ba and REE patterns). Developing methods for solution-based analysis (such as ICP-MS) was necessary due to the inherent challenges in fully dissolving graphite, given the robust carbon layers. Laser Ablation-ICP-MS offers a less time- and cost-intensive method, though it also required significant method development for sample preparation and calibration. The ablation of very fine-grained compressed materials and the lack of reference and calibration materials presented notable challenges. A significant proportion of trace elements in graphite concentrates are associated with impurities and accompanying mineralogical components. These impurities can be identified and delineated through the application of advanced statistical methods and data processing techniques. Analytical proof of origin (APO) methods are considered incorruptible, as they directly relate to the chemical composition of the raw material, offering significant potential for verification and control purposes. Unlike methods such as documents, tracers, QR codes and barcodes, which can be manipulated or falsified, APO methods provide a robust means of authentication. The developed APO methodology serves to facilitate the implementation of supply chain laws and battery regulations within the graphite industry.

KW - Graphite

KW - Traceability

KW - Geochemistry

KW - Graphit

KW - Herkunftsnachweis

KW - Geochemie

U2 - 10.34901/mul.pub.2024.209

DO - 10.34901/mul.pub.2024.209

M3 - Doctoral Thesis

ER -