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Measurement of Carbonate Minerals in Aerosol Samples- A Preliminary Study

Measurement of Carbonate Minerals in Aerosol Samples- A Preliminary Study. Johann Engelbrecht Desert Research Institute. X-ray Diffraction (XRD). XRD measures the presence and concentration of crystalline compounds (phases) such as minerals It does not record chemical concentrations.

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Measurement of Carbonate Minerals in Aerosol Samples- A Preliminary Study

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  1. Measurement of Carbonate Minerals in Aerosol Samples- A Preliminary Study Johann Engelbrecht Desert Research Institute

  2. X-ray Diffraction (XRD) • XRD measures the presence and concentration of crystalline compounds (phases) such as minerals • It does not record chemical concentrations

  3. X-ray Diffraction (XRD) Scan RS611-38 µm

  4. X-ray Diffraction (XRD) Scan RS611-PM10

  5. X-ray Diffraction (XRD) Scan RS611-PM 2.5

  6. X-ray Diffraction (XRD) Scan RS667-µm

  7. X-ray Diffraction (XRD) Scan RS667-PM10

  8. X-ray Diffraction (XRD) Scan RS646-38µm

  9. X-ray Diffraction (XRD) Scan RS646-PM10

  10. Minerals Identified in 20Re-suspended Aerosol Filter Samples • Quartz [SiO2] (common) • Carbonate Minerals • Calcite [CaCO3] • Aragonite [CaCO3] • Dolomite [CaMg(CO3)2] • Layered Silicates • Micas such as Muscovite • Vermiculite • Clays such as Dickite, Kaolinite & Montmorillonite • Chlorite

  11. Minerals Identified in 20 Re-suspended Aerosol Filter Samples • Feldspar Minerals • Anorthite • Microcline • Oxides • Rutile • Gypsum [CaSO4.2H2O]

  12. Chemical vs Mineralogical Ratios

  13. Chemical vs Mineralogical Ratios

  14. Soluble Ca vs Total Ca

  15. Carbonate vs Soluble Ca

  16. OC4 vs Soluble Ca

  17. Carbonate vs Total Ca

  18. OC3 vs Total Ca

  19. OC4 vs Total Ca

  20. OC4 vs Carbonate

  21. Chemical vs Mineralogical Ratios

  22. Mineralogical Reactions CaCO3 + SiO2 = CaSiO2 + CO2 calcite + quartz wollastonite 490 – 550 oC

  23. Mineralogical Reactions CaMg(CO3)2 + 4SiO2 + H20 = dolomite + quartz + water Mg3SiO4O10(OH)2 + 3CaCO3 + CO2 talc + calcite 150 – 250 oC

  24. Question • With the current TOR method, are we quantitatively measuring all the carbonate in the aerosol samples?

  25. Conclusions • Minerals can play an important role in aerosol samples which contain a significant amount of soil dust • XRD is an appropriate analytical tool for identifying & quantifying minerals on filter samples, but does require research • The TOR method for the measurement of mineral carbonate should be reviewed

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