A new distance correction method for sulfur analysis in coal using online XRF measurement system

When X-ray fluorescence (XRF) technology is used to measure the sulfur concentration in coal online, the measurement accuracy is affected by the coal’s uneven surface and the particle size. In order to improve the accuracy of sulfur concentration measurement, an online measurement system, consisting of a portable X-ray fluorescence instrument and an auxiliary distance correction module, was developed in this paper. By measuring the standard coal samples of known sulfur concentration, we obtained a calibration curve that can be used to analyze the sulfur concentration. We studied the relationship between the X-ray fluorescence intensity (I) and the distance (D) from surfaces to instrument. The results showed that there was a good linear relationship between I and D when the sulfur content was certain. Based on these knowledge, the distance correction formula of X-ray fluorescence intensity was proposed. By applying the distance correction formula to experimental sulfur concentration measurement, we demonstrated that the measurement accuracy can be significantly increased.