| The circulation and enrichment of volatile harmful components such as sulphur,chlorine and alkalis in cement kiln is a special phenomenon in the new type dry cementproduction process. The resulting skinning problem in kiln end and predecomposing systemis difficult to solve, especially for material and fuel with poor quality. The thesis combinesthermodynamic equilibrium calculation, offline XRD analysis and onlineThermogravimetric test, explores the influence factor of the volatilization of sylvite and theeffect of mineral on the migration of sylvite, in order to explain the high-temperaturevolatilization characteristics of KCl, K2SO4, K2CO3, as well as to explore the solidreaction mechanism of different cement mineral components such as CaCO3, SiO2, Al2O3and Fe2O3.Through the research on the high-temperature volatilization process of sylvite, wedraw the following conclusions. The volatilization temperature of KCl is the lowest becausehalogen element promotes the volatilization of sylvite. The volatilization temperature ofK2SO4is the highest. It volatilizes as a whole at first, and then decomposes to K、KO、O2and SO2as temperature increases. The volatilization temperature of K2CO3is intermediateas it doesn’t include Cl and S. It decomposes to K、KO and CO2while volatilizing.Through the research on the solid reaction mechanism between mineral and sylvite, wedraw the following conclusions. Mineral delays the volatilization process of KCl. Mineralis hard to react with KCl except for Al2O3.K2SO4is not active in the experiment condition,it is hard to decompose or react with mineral even at1400℃, only part of K2SO4can reactwith Al2O3.K2CO3is the most active and K is easy to be fixed. K2CO3can not only reactwith Al2O3or Fe2O3to produce KAlO2or KFeO2, it can also decompose to K2O thatco-melt with SiO2and react with CaCO3in low temperature to produce K2Ca(CO3)2.Interms of mineral, Al2O3fixes sylvite best and SiO2is easy to co-melt with K2O. |
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