| Crystalline silica can be introduced into the raw meals while waste concrete is used in cement production, and crystalline silica is harmful for the formation of clinkers. Focused on the problems, raw meals with high crystalline silica content were prepared and effect of doping on clinker formation and property were studied. X-Ray diffraction, reflection macroscope, thermal analyzer, and scanning electron microscope were used for the study, influence mechanism of doping was analyzed by calculation of Ea, on the basic of above-mentioned experiments, effect of doping on eco-cement produced from all components of waste concrete was studied.Firstly, clinker samples with different doping were analyzed in the paper, the results show that the burnability of raw meals added salg or F-S mineralizer was improved; B2O3has a negative effect on formation and quality of clinker; liquid phase in samples added salg and F-S mineralizer appeared earlier than the blank sample, crystallinity and mineral morphology were also improved and compressive strength of cement was enhanced, the effect of F-S mineralizer on raw meals is better than salg.For study the mechanism of doping, thermodynamics parameters of samples with different doping were calculated, the result showd that salg and F-S mineralizer increased the amount of liquid phase, reduced the viscosity of liquid, therefore, the apparent activation energy of C3S formation droped.At last, F-S mineralizer was added into the raw meals with wast concrete, the raw meals were sintered in a electic furnace at135O℃, the results of experiment showed that samples added with F-S mineralizer have a better burnability and compressive strength than blank sample; using wast concrete in cement production, parameters may be different from original cement, the appearance of clinkers is grayish-black, there are lots of small holes in clinker and its structure is loosened, inadequate parameters is the main reason. |
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