Expanding the Applicability and Estimating the Degree of Accuracy of the Method for Determining Organic Carbon in Waste Generated by Coal Mining Operations, Processing, and Burning

The article discusses the issue of expanding the applicability and evaluation of the metrological characteristics of the previously developed method for gravimetric determination of organic carbon in waste from mining, processing, and burning of coal. Thermogravimetric analysis and mass spectrometry (TGA/MS) prove that the effect of pyrite, often present in coal, is negligible in estimating the carbon content. The complete character of carbon extraction is confirmed at a temperature of 815°C. Real samples of wastes are obtained at sites of mining, processing, and coal burning for the studies. As well, the samples are analyzed that have a known composition prepared through addition and dilution and model substances made by sequential ashing coals having varying degrees of metamorphism (brown, hard, and anthracite) and different carbon contents in the entire determination range (from 0.5 to 60 wt %). It is found that there are no systematic errors in the results of carbon determination using the developed method. The accuracy, repeatability, and reproducibility are estimated for each of the four subranges of carbon determination. The measurement procedure is certified, and the registration number FR.1.31.2023.46507 has been assigned in the Federal Information Fund to Ensure Unity of Measurements. The possibility of using the measurement technique to characterize reference materials for calibration of express infrared carbon analyzers is explored.