Expanding the scope of application and evaluating the metrological characteristics of the method of determination of organic carbon in wastes of mining, processing and combustion of coal

The organic carbon content is one of the marker indicators for wastes of mining, processing and combustion of coal, which reflect the quality of drilling and blasting operations carried out at the deposit, enrichment and safety of gold and slag waste and fly ash. The article presents the results of studies on establishing the scope of application and evaluating the metrological characteristics of a developed analytical procedure for determination of organic carbon in samples of wastes of mining, processing and combustion of solid mineral fuel using the gravimetric method. The applicability of the procedure for rock samples containing pyrites, as well as the completeness of carbon extraction for coal samples of different degrees of metamorphism (brown, hard and anthracite) were tested using thermogravimetric analysis with mass spectroscopic detection (TGA/MS), which allows conducting a qualitative analysis of volatile substances (water, oxides of sulfur and carbon) released from the analyzed samples under the influence of high temperature. The scope of application and measurement range of the measurement procedure were confirmed by studying real samples of wastes of mining, processing and combustion of coal and specially prepared samples based on sequential ashing of coal samples. The absence of systematic bias in the measurement results according to the measurement procedure was established by analyzing attested samples based on rock samples, a standard sample of rock composition (mudstone) GSO 7223–96 (containing no carbon) and a standard sample of coal composition GSO 10877–2017 (with a specified carbon content) prepared by the addition method and the dilution method. The measurement procedure was certified and assigned registration number FR.1.31.2023.46507 in the Federal Information Fund for Ensuring the Uniformity of Measurements. The prospects for using the measurement procedure to characterize matrix reference materials required for constructing calibration characteristics of express infrared carbon analyzers are considered.