Studies to establish the possibility of using coal-enrichment waste as an energy raw material in ceramic technologies

Abstract

The article presents the results of a study of high-carbon coal-enrichment wastes that to be used in the technology of building ceramics to replace technological fuel at the stage of isothermal excerpt during the firing of semi-finished products. The mineral composition of the waste, the composition of its organic part, thermal and technological properties have been studied. The comparative characteristics of the properties of ceramic materials obtained on the basis of mixtures with the use of clay raw materials and coal waste in different quantities are given. In laboratory conditions, materials were obtained that were heat treated at a temperature of 950 °C under the usual regime and a special regime that simulates self-baking due to the heat of oxidation reactions of the combustible part of the coal waste. The expediency of using special oxidizing agents in the form of a combination of ammonium and calcium nitrate salts, whose function is to create an oxidizing medium in the fired material volume due to the formation of O2, NO2 and N2O oxidizing agents during thermal decomposition, is shown. It is established that the mechanical strength of ceramic samples is only 15 % less than for conventional firing samples and is 8.5 N/mm2 for mass with 22 % of coal waste. Based on the conducted studies, it is shown that it is possible in principle to use a special firing regime without consuming an energy carrier at the stage of excerpt for fuel-containing materials using coal waste as energy raw materials.