Thermal analysis was utilized to study the formation kinetics of high-temperature phase sulphoaluminate based on competitive reaction.Experimental investigation proved that the formation of sulphoaluminate began at 1100℃ and reached a maximum at 1331℃.High temperature resulted in the change of multi-crystals composed of CaO

Al2O3 and CaSO4·2H2O.The mobility of particles increased remarkably and accelerated the solid reaction process.The formation of high-temperature phase sulphoaluminate could be described by the first order reaction kinetics

and could belong to nucleus formation mechanism.