Experiment and thermodynamic analysis on Q-phase cement clinker cogeneration from coal in pulverized coal combustion boiler

Taking Changguang coal as experimental coal type, carrying out the experiment of Q-phase cement clinker co-generated from high-sulfur coal on two-section multiphase reaction test stand and conducting XRD analysis on the mineral composition in co-generation clicker sample, it was found that the major mineral species in compositions of co-generation clinker are 2CaO·SiO2, Q phase and calcium sulphoaluminate (3CaO·3Al2O3·CaSO4). According to the Gibbs free enthalpy G of state function, conduct thermodynamic calculation on the mineral formation reaction probably occurring in the chemical compositions of Q-phase cement clinker co-generated from Changguang coal, especially, calculate and compare the formation reactions of high-temperature sulfur capture product 3CaO·3Al2O3·CaSO4 and Q-phase that was the characteristic mineral of co-generation, and compare the priority of mineral formation reactions of clicker. The findings show that, according to the chemical composition of clinker, the direct synthesis reaction of 2CaO·Al2O3·SiO2 will firstly occur, followed by the direct synthesis reaction of 2CaO·SiO2, the next is the indirect synthesis reaction of Q-phase, and the last is the indirect synthetic reaction of 3CaO·3Al2O3·CaSO4; the final main mineral compositions of co-generation clinker should be 2CaO·SiO2, Q phase and 3CaO·3Al2O3·CaSO4; the conclusion of thermodynamic analysis on co-generation clicker mineral formation reaction basically conforms to the mineral composition in experiment of Changguang coal co-generating Q-phase cement clinker.