Figure E. Near real-time management of spectral interferences with portable XRF spectrometers: Application to Sc quantification in nickeliferous laterite ores

Figure E: The Ca/Sc threshold ratios defined for the ‘20 Cu’ method (a) and the ‘18 Fe’ method (b). For the ‘20 Cu’ method (a), only one limit is visible (Limit 2 = 1822), which determines the field of the values where the Ca-Sc spectral interference is correctly resolved (below this limit) and the field of values where the spectral interference is never solved (above this limit). The same observation was made for the ‘18 Fe’ method with a limit 2 = 2887 (b). Diamonds with black edges correspond to the 11 standards used to build the calibration line. Diamonds without an edge line correspond to the samples used for checking the calculated calibration line. Blue diamonds correspond to standards or samples for which the average of their eight measurements falls within ±2σ around the Sc-calibration curve. Red diamonds correspond to standards or samples for which the average of their eight measurements falls outside the ±2σ interval around the Sc-calibration curve.