Sample Preparation Facilities for XRF analysis
X-ray Fluorescence Spectrometry is an established non-destructive technique for rapid, multi-element analysis of bulk samples. Identification and quantitative estimation of almost any element from Boron to Uranium is possible at concentrations between 1ppm to 100%. The major advantages are minimum sample preparation, fast speed and good precision in analysis.
| Principle |
XRF spectrometry is one of the most widely used and versatile analytical technique. An XRF spectrometer normally uses primary radiation from an X-ray tube to excite secondary X-ray emission from a sample. The radiation emerging from the sample includes the characteristic X-ray peaks of major and trace elements present in the sample. Dispersion of these secondary X-ray into a spectrum, usually by X-ray diffraction, allows identification of these elements present in the sample. The height of each characteristic X-ray peaks relates to the concentration of the corresponding element in the sample, allowing quantitative analysis of the sample for most elements. The Solid samples are analysed in the form of pressed powder pellets or homogenised glass fused beeds.
The XRF laboratory at WIHG was established in 1979 with an Energy Dispersive XRF System (EDAX EXAM SIX) . The System produced useful data upto 1994 when it was replaced with a Siemens SRS-3000 sequential (wavelength dispersive) spectrometer. With enhanced capabilities SRS-3000 has been a work-horse for providing quality XRF data to large number of users spreading all over the country. To meet the increased demand from the users it was decided to enhance the analytical capabilities of the laboratory in the year 2010, again. Therefore an advanced XRF system was added in the laboratory. This new technological advanced system S8 Tiger from Bruker-AXS,Germany,with many useful features was procured and installed in September 2010. This spectrometer has the several advantageous features like high speed, accommodating 60 samples at a time, more precise elemental analysis with enhanced sensitivity and flexibility in terms of adopting several analytical modes including a special analytical program for analysis of rock/mineral samples. The built-in standardless analysis program is a useful tool for the qualitative analysis of completely unknown materials. The extended analytical range includes some of the very useful elements that can be analysed along with the usually analysed major and trace elements in geological samples. Special features include a High power X-ray tube of 4kW capacity providing more powerful excitation of elements, eight number of analyzing crystals and two x-ray detectors ( Gas flow proportional and scintillation) with three optimized coarse and fine collimators. Following are the key features available in the existing system (Bruker S8 Tiger)-
– End window 4 kW Rh anode tube ( 60 kV, 170 mA) – accepts samples or pellets with dia. 23,34 or 40 mm and height upto 51 mm – Nine analysing crystals ( LIF200, LiF220, Ge, PET, OVO-55, OVO-160, InSb and ADP – X-ray detectors SC and FPC
Elements routinely determined as weight % oxide in geological matrices are SiO2, TiO2, Al2O3, Fe2O3(total), MnO, MgO, CaO, Na2O, K2O, and P2O5. Trace elements routinely determined in geological samples at the> 5 ppm ( 2 ppm for some elements) level are Ba, Sc, V, Cr, Co, Ni, Cu, Zn, Ga, Pb, Th, Rb, U, Sr, Y, Zr and Nb .
Sample Requirement: Normally in powder form (-200 mesh). Quantity – 10 g
Sample Preparation Facility available-
| Automatic Hydraulic press ( 40 Ton) for making pressed powder pellet. |
| Fusion beed preparation machine PAnalytical Perl.X 3. |
| Planetary Ball Mill (Reitsch PM-100) for fine powdering. |