Glass Beads for XRF Analysis of Cement

xrFuse2

Tools and Materials

  • xrFuse crucibles in Pt95/Au5 ([email protected] 30 g)
  • An xrFuse2 (electrical fusion machine)
  • An analytical balance with a precision of 0.1 mg and a weighing range of about 200 g
  • xrFuse moulds in Pt95/Au5 ([email protected] 100 g – bead = Ø39/41 mm x 4 mm)
  • A weighing spatula to weigh the sample
  • A spoon-spatula to weigh the oxidizer and flux
  • A weighing pan or other
  • A furnace for calcination of the sample before fusion (950 °C)
  • A vortex mixer to mix the flux and sample together
  • A long pair of tongs (20 cm) with plastic tips (to avoid scratching the mould and the crucible)
  • An ultrasonic cleaner (with heating) to clean the platinum labware

Note: 95% Platinum 5% Gold (Pt/Au): Universally accepted material of choice for casting and crucible moulds for spectrographic analysis by x-ray fluorescence (XRF).
Note: Never touch the casting surface with tongs: any scratches will transfer to the glass bead measurement surface.

The Chemicals

  • Citric acid (a 20% solution to clean the moulds and the crucibles)
  • The flux:
    • FLUX LT66/LM34: Lithium tetraborate 66%, Lithium metaborate 34% - (Tm 875 °C)

Calcination

All samples were calcined at 950 °C  for 2 hours before the fusion and the production of the beads.

Preparations of Casting Powders for Fusion

Preparations of Casting Powders for Fusion

Preparations of Casting Powders for Fusion

1.000 g +/-0.015 g of sample and 8.000 g of flux FLUX LT66/LM34 should be directly weighed into a fusion crucible and mixed together. In order to ensure that the contact between flux and sample is optimized, the mixture should be thoroughly mixed (about 0.5 minute).

  • The crucible containing the powder should be placed into the crucible cradle of the xrFuse2
  • The mould should be placed on the mould holder of the xrFuse2
  • The desired program should be loaded and the start button be pressed
  • The bead should be removed from the mould, once the fusion is complete

Note: Never touch the measurement side with your fingers (the side that faced the casting dish surface).

Fusion Program Settings

Program

Function Time (seconds) Temp. °C Speed (%) Angle
Pre-melt time 30 850
Melt time 120 1050
Shake time 240 1050 90 45°
Stand time 30 1050
Pouring 30
Stage 1 Cooling 120 20
Cool time 480 100
TOTAL TIME: Program 1 : 18 min; Cold-to-Cold:

This information has been sourced, reviewed and adapted from materials provided by XRF Scientific.

For more information on this source, please visit XRF Scientific.

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