The Fusion temperature and dynamic behavior of the fusion process for ash mixtures being composed of representative ash sample taken from two coal-water slurry fired boilers have been deeply studied. It was discovered that the fusion temperature of ash mixture made up from two single ash samples with similar fusion behavior and higher fusion points is still higher

but the fusion temperature of ash mixture made up from two ash samples with very low and very high fusion points is gradually heightened along with increasing the mixed ratio of ash sample with higher fusion point.