Pt 28.835 Pd 29.999 Rh 130.21 Au 64.797 Ag 0.737

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Handheld XRF vs. Fire Assay

Fire assay is a very common, reliable and accurate assay method. When assaying gold, refineries use fire assay as the primary tool for crediting their customers.

In this short test we compare 15 fire assays results with assay results of a handheld XRF device, to check whether it could be used instead of the fire assay technique.

The XRF tests were conducted with the Niton XL3t GOLDD+ using the “Precious Metals” mode, at duration time of 30 seconds per assay.

Results

The table below shows the results of 15 sampled assays of gold with various purities, performed by both fire assay and Niton XL3t GOLDD+. Results are presented as percent of gold in the sample.

SampleFire Assay
% of gold in sample
XRF
% of gold in sample
Delta %
180.0179.760.312461
268.7769.9-1.64316
357.6457.7-0.10409
457.5157.110.695531
558.0657.880.310024
678.2377.720.651924
711.9211.96-0.33557
857.6857.440.416089
959.7559.220.887029
1065.0864.970.169023
1154.0753.80.499353
1299.2699.160.100746
1350.750.620.157791
1476.2375.60.826446
1558.4658.090.632911

Below is a graphic representation of the results with correlation coefficient R squared.

xrfvsfr

Conclusion

The above graph presents an R2 correlation coefficient of 0.9995, which is a great result. However, even a small difference in results would not be accepted by gold refineries.

Our recommendation would be to use the XRF as a preliminary assay both for the gold content and for other components of the alloy (such as identifying hazardous materials in the alloy).