电石渣和煤矸石对型煤固硫性能的影响及作用机制研究OA北大核心CSTPCD

The development of high-temperature-resistant sulfur-fixing agents and addi-tives that are both high efficiency and low cost is helpful for addressing the decomposition prob-lem of calcium-based sulfur-fixing products in the high-temperature combustion environment of briquette.Calcium carbide slag and coal gangue are typical industrial solid wastes.Utilizing these materials as an additive to prepare sulfur-fixing briquettes from solid waste can reduce the costs of sulfur-fixing briquettes and enhance the value of solid waste resources.The synergistic effect of the mineral components in these wastes can improve the sulfur fixation efficiency of briquette at high temperatures.The preparation of environmental-friendly sulfur-fixing agents and addi-tives of coal briquettes using calcium carbide slag and coal gangue was studied.The effects of va-rious parameters on the sulfur fixation efficiency of coal briquettes were investigated,including the types of sulfur-fixing agents(calcium carbonate,calcium oxide,calcium hydroxide and calci-um carbide slag),the molar ratio of calcium to sulfur(1.5-4.0),the combustion temperature(900℃-1 300℃),and the coal gangue dosage(2%-7%).The evaluation experiment of coal briquette combustion show that coal briquettes produced with a molar ratio of calcium to sulfur of 3.0,using only calcium carbide slag as the sulfur-fixing agent,achieve a sulfur fixation ratio over 80%when the combustion temperature is below 1 000℃.However,as the combustion tempera-ture increases to 1 300℃,the sulfur fixation ratio of coal briquettes decreases by 40%.Analysis indicates that this decrease is mainly due to the high-temperature decomposition reaction of the sulfur-fixing product calcium sulfate.The added coal gangue,when activated by calcium carbide slag components at high temperatures,serves as an auxiliary sulfur-fixing agent.When the mass fraction of added coal gangue reaches 5%,the sulfur fixation ratio of the briquettes remains above 60%.Further increasing the amount of coal gangue does not significantly improve the sulfur fixa-tion ratio of briquettes.Thermal stability of sulfur fixation products and the analysis and charac-terization data reveal that the active components of high-alumina coal gangue slag undergo high-temperature reactions to form stable phases such as calcium sulphoaluminate,gehlenite,and tri-calcium silicate.These phases restrain the decomposition of CaSO4,thereby improving the high temperature sulfur fixation rate of briquettes.