QEMSCAN

QEMSCAN

QEMSCAN Automated Mineralogy solution
Invented by CSIRO
Launch year 2001
Company FEI Company
Availability yes
Current supplier FEI Australia Center of Excellence for Natural Resources
Last production year 2013
Website http://www.fei.com/applications/industry

QEMSCAN is the name for an integrated automated mineralogy and petrography solution providing quantitative analysis of minerals, rocks and man-made materials. QEMSCAN is an abbreviation standing for Quantitative Evaluation of Minerals by SCANning electron microscopy, and a registered trademark owned by FEI Company since 2009. The integrated system comprises a Scanning Electron Microscope (SEM) with a large specimen chamber, up to four light-element Energy-dispersive X-ray spectroscopy (EDS) detectors, and proprietary software controlling automated data acquisition. The offline software package iDiscover provides data processing and reporting functionality.

Mineral identification and quantification

QEMSCAN creates phase assemblage maps of a specimen surface scanned by a high-energy accelerated electron beam along a predefined raster scan pattern. Low-count energy-dispersive X-ray spectra (EDX) are generated and provide information on the elemental composition at each measurement point. The elemental composition in combination with back-scattered electron (BSE) brightness and x-ray count rate information is converted into mineral phases.[1] QEMSCAN data includes bulk mineralogy and calculated chemical assays. By mapping the sample surface, textural properties and contextual information such as particle and mineral grain size and shape, mineral associations, mineral liberation, elemental deportment, porosity, and matrix density can be calculated, visualized, and reported numerically. Data processing capabilities include combining multiple phases into mineral groups, resolving mixed spectra (boundary phase processing), image-based filtering, and particle-based classification. Quantitative reports can be generated for any selected number of samples, individual particles, and for particle classes sharing similar compositional and/or textural attributes, such as size fractions or rock types.

Sample types and preparation

QEMSCAN is routinely employed in the analysis of rock- and ore-forming minerals. Sample preparation requirements include a level, dry specimen surface, coated with a thin electrically conductive layer (e.g. carbon). The sample must be stable under high vacuum conditions and the electron beam, typically 15 to 25 kV. Common sample types include 30 mm resin-impregnated blocks of drill cuttings and ore, thin sections of drill core and rocks, as well as soil samples. Very small particles such as atmospheric dust have been measured on carbon tape or filter paper. Coal samples are generally mounted in carnauba wax, providing sufficient contrast to allow for separation of the sample from the mounting medium, and subsequent measurement of coal and macerals.

Software suite

QEMSCAN consists of proprietary software package iDiscover which consists of four software modules:

  1. Datastore Explorer - Data management module
  2. iMeasure - Measurement module, SEM and EDS control
  3. iExplorer - Data processing and classification tools, mineral database management, reports
  4. SIP editor - phase identification protocol

Measurement modes

QEMSCAN consists of five customisable measurement modes

  1. BMA Bulk Mineralogical Analysis
  2. PMA Particle Mineralogical Analysis
  3. SMS Specific Mineral Search
  4. TMS Trace Mineral Search
  5. Field Image surface imaging mode

Applications

QEMSCAN measurements can be applied in quantitative mineral characterisation of rocks, weathering products such as regolith and soils, and most man-made materials. As a result it has commercial and scientific applications in mining and mineral processing;[2] O&G;[3] coal;[4] environmental sciences;,[5][6] forensic geosciences;[7] archaeology;[8] agribusiness; built environment and planetary geology.[9]

History

References

  1. ↑ Gottlieb, P., Wilkie, G., Sutherland, D., Ho-Tun, E., Suthers, S., Perera, K., Jenkins, B., Spencer, S., Butcher, A., Rayner, J. 2000. Using quantitative electron microscopy for process mineralogy applications. JOM - Journal of the Minerals, Metals and Materials Society, 52, 4, 24-25. doi:10.1007/s11837-000-0126-9
  2. ↑ Goodall, W.R., Scales, P.J., Butcher, A.R. 2005. The use of QEMSCAN and diagnostic leaching in the characterisation of visible gold in complex ores. Minerals Engineering, 18, 8, 877-886 doi:10.1016/j.mineng.2005.01.018
  3. ↑ Fröhlich, S., Redfern, J., Petitpierre, L., J.D. Marshall, M. Power, Grech, P. 2010. Diagenetic evolution of incised channel sandstones: implications for reservoir characterisation of the Lower Carboniferous Marar Formation, Ghadames Basin, Western Libya. Journal of Petroleum Geology, 33; 3-18. abstract
  4. ↑ Liu, Y., Gupta, R., Sharma, A., Wall, T., Butcher, A., Miller, G., Gottlieb, P., French, D. 2005. Mineral matter–organic matter association characterisation by QEMSCAN and applications in coal utilisation. Fuel, 84, 10, 1259–1267. doi:10.1016/j.fuel.2004.07.015
  5. ↑ Haberlah, D., Williams, M.A.J., Halverson, G., Hrstka, T., Butcher, A.R., McTainsh, G.H., Hill, S.M., Glasby, P. 2010. Loess and floods: high-resolution multi-proxy data of Last Glacial Maximum (LGM) slackwater deposition in the Flinders Ranges, semi-arid South Australia. Quaternary Science Reviews, 29, 19-20, 2673–2693. doi:10.1016/j.quascirev.2010.04.014
  6. ↑ Haberlah, D., Strong, C., Pirrie, D., Rollinson, G.K., Gottlieb, P., Botha, W.S.K., Butcher, A.R. 2011. Automated petrography applications in Quaternary Science. Quaternary Australasia, 28(2), 3–12
  7. ↑ Pirrie, D., Power, M.R., Rollinson, G.K., Wiltshire, P.E.J., Newberry, J., Campbell, H.E. 2005. Automated SEM-EDS (QEMSCAN) Mineral Analysis in Forensic Soil Investigations: Testing Instrumental Reproducibility. In:K. Ritz et al. (eds.) Criminal and Environmental Soil Forensics, 84, 10, 411-430, Springer Science doi:10.1007/978-1-4020-9204-6_26
  8. ↑ Knappett, C., Pirrie, D., Power, M.R., Nikolakopoulou, I., Hilditch, J., Rollinson, G.K. 2005. Mineralogical analysis and provenancing of ancient ceramics using automated SEM-EDS analysis (QEMSCAN): A pilot study on LB I pottery from Akrotiri, Thera. Journal of Archaeological Science, in press doi:10.1016/j.jas.2010.08.022
  9. ↑ Schrader, C.M., Rickman, D., Stoeser, D., Wentworth, S.J., Botha, P.W.S.K., Butcher, A.R., McKay, D., Horsch, H., Benedictus, A., Gottlieb, P. 2008. Analysis of Lunar Highland Regolith Samples from Apollo 16 Drive Core 64001/2 and Lunar Regolith Simulants - An Expanding Comparative Database. NASA Technical Report, MSFC-2144 abstract
  10. ↑ Frost, M. T., O'Hara, K., Suddaby, P., Grant, G., Reid, A.F., Wilson, A.F., Zuiderwyk, M. 1977. A description of two automated control systems for the electron microprobe. X-Ray Spectrometry, 5, 4, 180-187. doi:10.1002/xrs.1300050403

External links

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