Mineral Carbonation Potential and Transition Metal Migration in Kimberlite and Ultramafic Rocks: An Integrated Study of Acid Leaching, Enhanced Rock Weathering, and Microbial CO2 Sequestration

• Author / Creator

  Wang, Baolin

• Carbonation of mafic and ultramafic rocks and mineral wastes provides a permanent way to sequester excess atmospheric CO2. Recent research has shown that this method also offers the potential for enhanced recovery of critical metals from mine tailings. This thesis presents a comprehensive study on the potential for CO2 sequestration through the carbonation of ultramafic rocks and mineral wastes from diamond mines. Utilizing a variety of analytical and experimental methods, this research aims to enhance our understanding of mineral carbonation processes and their application in offsetting CO2 emissions, while also exploring the recovery of critical metals from mine tailings.

  The first part of the thesis introduces an innovative application of the Partial Or No Known Crystal Structure (PONKCS) method combined with the Rietveld method and X-ray diffraction (XRD) to perform Quantitative Phase Analysis (QPA). This approach overcomes the limitations of standard methods in quantifying structurally disordered minerals like lizardite and smectites in kimberlite, which are reactive to CO2. The study highlights the importance of instrument-specific calibration for accurate QPA and CO2 mineralization quantification in clay-rich rocks.

  The second part of the thesis evaluates the carbonation potential of processed kimberlite from the Venetia diamond mine through column acid leaching experiments. The study demonstrates the feasibility of CO2 offset and critical metal recovery during mineral carbonation, with acid concentration significantly influencing the extraction of Mg and Ca, essential for carbon sequestration.

  The third part of the thesis expands on the theme of accelerated carbon mineralization, investigating the influence of mineralogy on the weathering and carbonation potential of various ultramafic rocks and processed kimberlite. Through acid leaching experiments, the research underlines the crucial role of specific mineral compositions in determining the efficiency of CO2 sequestration and suggests a significant potential for offsetting greenhouse gas emissions from mining operations.

  Finally, a field trial conducted over a year examines the effectiveness of pH-swing and cation exchange methods combining with microbially-mediated method for carbonating serpentine-, smectite- and calcite-rich processed kimberlite. The results indicate promising strategies for enhancing weathering and carbonation, tailored to the unique mineralogy of each rock type. The study advocates for the integration of acid leaching and microbially-mediated carbonation for calcite-poor residues, and a novel cation exchange approach for calcite-rich tailings, to maximize CO2 sequestration.

• Subjects / Keywords

  • Rietveld method
  • PONKCS
  • carbon mineralization
  • carbonation potential
  • transition metals
  • ultramafic rocks
  • mineral wastes
  • accelerated weathering
  • microbial CO2 removal

• Graduation date

  Fall 2024

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/r3-b743-cx81

• License

  This thesis is made available by the University of Alberta Library with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.