Study On The Effect Of Cooling Ways On The Mineral And C₃S Crystal Form Of Cement Clinker

Clinker is an important component of cement,as a determinant of its performance.Under the strategy of low-carbon and sustainable development in China,cement industry is advocated to develop towards the goal of low energy consumption,excellent performance and strong durability.The performance of clinker is the key to cement production,and the cooling rate is one of the important factors which affect the cement production under various conditions.Therefore,this topic takes the cooling rate of clinker as the starting point,calcines the raw cement materials obtained from each cement plant at the same temperature,and studies the correlation between the cooling rate and the mineral composition of clinker and the type of C₃S crystal by changing the cooling method.At the same calcination temperature,the clinker with different cooling rate is found to have different color and density.The clinker cooled by liquid nitrogen has the best density,and the clinker is brown yellow.The clinker cooled by self-heating is black,and the clinker with furnace cooling has the worst density,and the clinker structure is sparse and gray.The raw materials were calcined at 1400℃and 1450℃respectively.It was found that the content of f-Ca O in the samples calcined at 1450℃was the lowest.The cooling speed is fast and the content of f-Ca O is low.The decrease of cooling rate makes the clinker firing effect worse.Increasing the temperature and accelerating the cooling rate is beneficial to reduce the free calcium oxide in the clinker.In addition,temperature has a significant effect on the composition of C₃S.The peak strength of C₃S at 1450℃is higher than that at 1400℃,and increasing temperature can effectively increase C₃S.By comparing the same calcination temperature and changing the cooling rate of the clinker,the corresponding relationship between the cooling rate and the C₃S crystal type was explored,The results show that:the diffraction peak of C₃S is high and narrow in the condition of liquid nitrogen cooling and natural cooling,while the characteristic peak of C₃S in the sample is short and blunt and wide in the condition of liquid nitrogen quenching and fast air cooling.C₃S can be formed well in the condition of liquid nitrogen quenching and fast air cooling,but is not formed well in the condition of slow cooling.The fast cooling C₃S crystal of clinker is M1 or M3,and the slow cooling C₃S crystal is M3 or T.As the cooling rate of clinker slows down,the symmetry of diffraction peak in characteristic interval of C₃S will be enhanced,and the crystal shape of C₃S will change from M to T.By comparing mineral characteristics at different cooling rates,the results show that quick-cooling clinker crystals have no time to grow.The crystals of A and B ore are small,with complete crystal shape,clear boundary,few inclusions and almost no dissolution and adhesion phenomenon.However,there are A lot of vitreous bodies around A and B ore,and the content of intermediate phase of clinker is low.For slow cooling clinker,the crystals of A and B ore are coarse,but the size is different,the boundary is fuzzy,the dissolution and adhesion phenomenon is serious,and there are many inclusions.The cooling grain size of Alite is 5～20μm,and most of them are long columnar or spindle-shaped.The slow cooling is long columnar or hexagonal plate with the size of 25～45μm.