Determination of phosphorus in raw materials for ceramics: comparison between X-ray fluorescence spectrometry and inductively coupled plasma-atomic emission spectrometry

Abstract

This paper compares methods for phosphorus determination in refractory silicoaluminous materials based on inductively coupled plasma-atomic emission spectrometry (ICP-AES) and X-ray fluorescence (XRF) spectrometry. Chemical interferences were studied by using several calibration standards and standard additions. The limits of detection obtained by XRF spectrometry (0.03 and 0.06 mg P 2O 5 per gram of sample) are clearly advantageous as compared with those obtained by ICP-AES (0.2 mg g −1). Phosphorus can successfully be determined by XRF spectrometry with either pressed sample pellets or diluted sample beads. Matrix effects were minimised by using a certified bauxite as a standard, but several less-similar materials could be used, such as siderurgic slag, chamotte and even dolomite for low P 2O 5 content samples. The linear calibration range is larger (up to 100 mg g −1) when analysis is carried out by ICP-AES, using the 213.628 nm line. Repeatability is similar with both methods, but XRF spectrometry is preferred on the grounds of the better sensitivity achieved, and the simpler sample preparation requirements.