Determination of Sulfur in Different Types of Geochemical Samples by ICP-OES with Acid Dissolution and Combustion-Infrared Absorption Spectrometry

BACKGROUND： Inductively coupled plasma-optical emission spectrometry (ICP-OES) and combustion-infrared absorption spectrometry are the most widely used methods to measure sulfur content in geological samples. The ICP-OES method has high sensitivity and good stability, but it is greatly affected by sample pretreatment and matrix interference. Combustion-infrared absorption spectrometry is convenient and efficient, but due to the interference of crystal water infrared absorption, the analysis of samples with low sulfur content has poor stability. OBJECTIVES： To study the application scope of the two methods in geological sample analysis. METHODS: The sulfur content of samples was determined by ICP-OES and combustion-infrared absorption spectrometry. The detection limit, detection range, precision, accuracy and analysis efficiency of the two methods was compared in order to study and understand the performance of the two methods in sulfur measurement of geological samples. RESULTS: The best test condition of combustion-infrared absorption spectrometry was determined thus: optimal sample weight of 0.0500g, combustion time of 25s, analysis time of 40s and oxygen analysis flow rate of 4.0L/min. The detection limit of combustion-infrared absorption spectrometry was 10×10-6 and the detection range was 10×10-6-470000×10-6. The accuracy relative standard deviation (RSD) of the method was less than 6% (n=12) and the absolute value of relative error was less than 8%. CONCLUSIONS: For the analysis of low-sulfur samples, ICP-OES method can be used to analyze or compare, and multi-element simultaneous measurement can be determined. Batch samples or samples with a complex matrix can be analyzed by combustion-infrared absorption spectrometry, which is more convenient and efficient

Effect of Pressure Relief Hole Spacing on Energy Dissipation in Coal Seam at Various Mining Depths

The large diameter pressure relief borehole is one of the most effective technical means to prevent and control rockburst during deep mining. Based on the engineering background of rockburst mines, the mechanical model of coal energy dissipation of large diameter pressure relief holes is established by theoretical analysis, and the approximate formula for calculating energy dissipation of coal is obtained. Combined with numerical simulation methods, the energy accumulation and dissipation laws of coal under various mining depths and the various spacings of pressure relief holes is studied. The results show that the upper and lower ends of the pressure relief holes have the highest degree of energy dissipation and the largest range of energy dissipation. While the energy dissipation effect on the left and right sides of the pressure relief holes is poor, a high accumulation of elastic strain energy occurs at a certain distance on the left and right sides of the relief holes. The dissipated energy of the coal seam increases continuously with the increase in mining depth and the decrease in spacing of pressure relief holes. The dissipated energy rises especially suddenly when the hole spacing changes from 1.0 m to 0.5 m. For coal seams with high rockburst risk, the spacing of pressure relief holes can be set to be less than or equal to 0.5 m, which can greatly improve the energy dissipation effect of coal seams. The studies can provide a theoretical basis for the optimization parameters of pressure relief holes for rockburst prevention