| The traditional white Portland cement（WPC）cooling process has not been adapted to the requirements of modern high-grade WPC production technology.It is of great significance to develop and research WPC clinker cooling process and new cooling medium suitable for the decomposition and calcination technology outside the kiln for my country’s WPC industry to catch up with the international advanced level.In order to fill in the blank of the influence of cooling medium on the color of WPC clinker in China,the influence of two common cooling mediums on the crystal form and color rendering characteristics of the main single minerals of WPC was studied by XRD and spectrophotometer.Quantitative analysis,metallographic microscope,SEM-EDS and spectrophotometer were used to study the effects of six cooling media on the color characteristics and mineral composition of WPC clinker.The effect of medium cooling on the hydration exothermic properties of WPC clinker.Research indicates:（1）Under the cooling condition of common medium,the overall Hunter whiteness of silicate minerals is higher.The use of water cooling can improve the whiteness of each mineral.Water cooling can significantly reduce the yellowness value（b*）of C3S and increase the lightness（L*）of C2S.The green color cast of C3A is the most pronounced,but the green color cast can be weakened by water cooling.（2）Cooling medium can significantly affect the color rendering performance of clinker.Compared with water-cooled clinker,EDTA-disodium,thiourea dioxide and CaCl2 solution cooling have whitening effect on WPC clinker,among which the yellow cast of air-cooled clinker is the largest,while the green color of thiourea dioxide solution-cooled clinker is the largest.Strongest color cast.（3）Cooling medium has a significant effect on clinker mineral composition and C3S crystal form.The C3S in the air-cooled clinker is mainly T3 crystal form,and the water and solution-cooled clinker is mainly the M1 and M3 type.Water cooling and solution cooling can inhibit the decomposition of C3S and reduce the content of f-CaO in clinker.Under the condition of solution cooling,the overall content of mesophase minerals is lower,and the ACn of water-cooled and thiourea dioxide-cooled clinker is significantly increased.（4）Cooling medium affects the solid solution tendency of Fe and Mg in clinker.Compared with water cooling,solution cooling can promote the solid dissolution of Fe and Mg in the mesophase and ACn,thereby affecting the color and quality of clinker.（5）The hydration rate of C3S and C2S is significantly lower than that of the intermediate phase.The water cooling process can greatly reduce the hydration heat of C3S,improve the early hydration rate of C2S,and improve the hydration efficiency and cumulative heat release of C4AF.（6）The cooling medium affects the heat release rate,induction period and cumulative heat release of WPC at different stages.Compared with water-cooled clinker,thiourea dioxide has slower hydration rate and lower hydration heat release.EDTA-disodium has the highest initial heat release rate,but the middle hydration slows down.Faster,the cumulative heat release is the lowest. |
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