The viability of using pulsed laser excited Raman spectroscopy as a method for diamond detection from ore, has been
investigated. In this method the spontaneous Stokes Raman signal is used as indicator of diamond, and a dual channel system is
necessary for correcting for fluorescence of minerals and diamond itself. Various pulsed laser wavelengths from 266 to 1064nm
were used, as well as cw lasers for comparison. Wavelength scans of the regions of interest, indicated that pulsed lasers at 532, 355
and 308nm may be used with confidence for this purpose. Mineral fluorescence did not appear to pose a threat to the method, but
rather own fluorescence of some types of diamonds. In this respect, pulsed lasers offer a decided advantage above cw, due to nonlinear
increase of fluorescence with laser power, resulting in superior Raman to fluorescence signal ratios. An apparatus constructed
for discriminating diamond from ore was evaluated, and using minerals commonly occurring in diamond carrying ore as well as a
wide variety of diamonds, it proved to function effectively. A significant improvement in the capability for diamond detection was
found when pulsed lasers at 532 and 308nm were used, in comparison to the 532nm cw laser.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:tut/oai:encore.tut.ac.za:d1000795 |
| Date | 29 June 2007 |
| Creators | Lamprecht, GH, Human, HGC, Snyman, LW |
| Publisher | Elsevier |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | |
| Rights | Elsevier |
| Relation | International Journal of Mineral processing |
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