The limiting content of combustibles to spread/suppress the fire in the minestone of the coal tailing dump (gangue) was studied. This knowledge appears crucial mainly when deciding on the possible usage of minestone as fireproof material for engineering purposes. Theoretical analysis, laboratory experiments as well as scale (in situ) considerations were performed. In the laboratory, a model series of coal–mineral matter mixtures and six representative minestone samples of coal tailing dump (gangue) were investigated. The thermoanalytical (TG/DSC) method was used to evaluate the content of combustibles with their energetic equivalent, EEC (%). The EEC has been suggested as a proper way to quantify the content of combustibles in the samples. Based on the original combustion calorimetric test, an EEC value of 7–9% was found to be a limit between fireproof and fire spreading minestone in a laboratory, while only 2% of combustibles resulted as the limit from the theoretical analysis. On the other hand, respecting real conditions of thermally active dump (Heřmanice tailing coal dump), the laboratory limit of 7–9% of EEC was then assessed to shift to the value of about 10 ± 1% for practice.
A series of coal-mineral matter mixtures was investigated by bomb combustion calorimetry (IKA C4000, Germany) to elucidate boundary for ash content in coal at which combustion proceeds with lowered efficiency. For the experiments, a high rank bituminous coal was mixed with particles of mine stone, both being milled to size below 0.2 mm. Before the usage, the sample of stone was heated at 900°C for 2 hours in air to stabilize mineral matter composition. Mixtures 5, 10, 15, 20, 25, 30, 40, and 50% of coal were used, with sample weights both of 1 g and/or 2 grams being applied. The efficiency of the combustion process at the bomb test was assessed of the measured calorific value and that of “theoretically” calculated. The “theoretical” calorific value of the mixture was determined from the actual content of the coal proving known specific calorific value (36.6 MJ/kg). Based on the measurements, mineral matter content of about 50% was found as limiting for fully efficient combustion of coal in the bomb calorimeter. At content of 90% of mineral matter, the efficiency of combustion is about 70 % (sample weight 1 g) and/or 50 % (sample weight 2 g). Afterwards, the combustion efficiency steeply decreases to zero.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.