Effect of cao on melting characteristics of high calcium bituminous coal CaO对高钙烟煤熔融特性的影响

Abstract

By adding different amounts of CaO in the coal ash of the high-calcium bituminous coal, the ash fusion characteristics of the high-calcium bituminous coal and the change of the melting temperature of the high-calcium coal ash under different CaO additions were studied. The FactSage thermodynamics software was used to simulate the mineral transformation law and the ternary phase diagram of the coal ash, which was used to verify the experimental results of different components. The results show that with the increasing of the CaO content, the melting characteristic temperature of the coal ash firstly decreases and then gradually increases. The CaO is often used as a flux, and a small amount of CaO addition causes a decrease in the melting point of the coal ash. However, when the CaO content in the coal reaches a certain value, a low-temperature eutectic is formed between the minerals in the coal ash, and the ash melting point reaches a minimum value. As the CaO content continues to increase, high-melting minerals such as the wollastonite and the single crystal calcium oxide appear in the coal ash, which leads to a gradual increase in the melting point of the coal ash. The change in the melting characteristic temperature is consistent with the calculated liquidus temperature results and phase diagram results obtained by the software, and the experimental result also shows the reliability of the FactSage software calculation results.