Research Of Phase Transition Of Gypsum In Fertilizer Salt Solution And Compound Fertilizer Granulation Mechanism

In this paper, based on the internal structure of binders andmaterial, the effect of interaction between particles and thegranulation mechanism of compound fertilizer was investigated. Andflue gas desulfurization(FGD) gypsum and fly ash, as solid binders, notonly increase the utilization way of waste, but also improve thefertilizer granulation effect.Firstly, transformation of FGD gypsum in fertilizer salt solution atatmospheric pressure was studied. The effect of concentration offertilizer salts, system temperature, pH, modifiers on transformationof gypsum were examined. It was showed that the conversion ofgypsum reached90%, about30min, with system temperature of98C, fertilizer salts concentration of40%, pH of3.15. Aftertransformation, crystals mainly existed in form of slender needlegypsum whisker, which Increasing the specific surface area of thegypsum and preparing for a better application for the FGD gypsum inthe fertilizer granulation.Secondly, under the action of ammonium sulfate, humic acidcompound fertilizer granulation condition was studied, and the effectthe different solid binders on humic acid compound fertilizer werecompared. From the change of viscosity and the interaction (physicaland chemical) between the material point of view, we found that ammonium sulfate of1-2%play a key role in the granulation process,and have a more significant effect with gypsum as binder.Finally, the fly ash fertilizer granulation was studied. Based on thecomposition of fly ash, we also researched the effect of internalstructure and active substance on fly ash activity. Thereby we tookfurther studies the feasibility of fly ash in granulation, which expandthe access to utilization of fly ash.All in all, based on the internal structure of the material and thesolid binder, the effect of mechanism of interaction material and thesolid binder were investigated. so as to lay the theoretical foundationfor fertilizer granulation and also increases the cyclic utilization waysof solid waste, which meets the requirements of circular economydevelopment.