QEMSCAN

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. Prior to 2009, QEMSCAN was sold by LEO, a company jointly owned by Leica and ZEISS. 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. 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:
Measurement modes.
QEMSCAN consists of five customisable measurement modes:
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; O&G; coal; environmental sciences;, forensic geosciences; archaeology; agribusiness; built environment and planetary geology.