Research on Methods for Rapid Determination of Harmful Elements Fluorine and Chlorine in Coal

Based on GB/T 4663-2014 (Determination Method of Fluorine in Coal) and GB/T 3558-2014 (Determination Method of Chlorine in Coal), after adjusting pH and constant volume of the aqueous solution absorbed by hydrolysis of coal sample by high-temperature combustion. The solution was accurately measured and divided into 2 parts. Fluorine ion selective electrode and potentiometric titration method were used to determine fluorine and chlorine in coal respectively. The content of fluorine and chlorine in coal is calculated by deduction. The study also explored the impact of the original absorption liquid transfer volume and the number of absorption stages on the determination results. Ultimately, a single-stage absorption with 10 mL of water as the absorption solution was selected. For the determination of fluorine content, 50 mL of the absorption solution was pipetted, while for the determination of chlorine content, 45 mL of the absorption solution was pipetted. In addition, through the study of precision and accuracy, it is confirmed that the method is not only less time and labor than the standard method, but also has the characteristics of good repeatability and reproducibility, simple and rapid operation.