Yali Wang;Suping Cui;Bichuan Chi;Lingling Liu;
<正>In new dry way predecompostion cement production,after preheating,raw meal comes into a calciner,and decomposition reaction occurs in,and then freshly generated CaO into a solid state reaction process in the kiln.The three stages are closely related to and affected one another.The formation rate of clinker mineral phases is closely related to activity of the decomposition product,calcium oxide,and calcium oxide with a higher activity is helpful to accelerate the mineral phase formation and then to decrease the corresponding calcining temperature.However,there are large differences in activity values of the decomposition formed calcium oxides under various calcination conditions. In this paper,the freshly generated CaO prepared by calcinating limestone under different decomposition temperature.The hydration exothermic rates of freshly generated CaO are determined by the 8-channel conductive microcalorimeter.In order to study influences of different decomposition temperatures on the activity of the formed CaO during solid state reactions,the amount of free CaO generated through the reactions between the decomposition products of limestone and SiO_2 are determined by chemical analysis.The results show that the decomposition temperature has a great impact on the solid state reactions of CaO.Decomposition rate will be increased by enhancing decomposition temperature,whereas reaction activity of CaO will be decreased at a higher decomposition temperature.As a consequence,an appropriate decomposition temperature is needed as a controlling parameter so that majority of the decomposition of raw meal can be completed in the calciner,and the generated CaO by the decomposition of raw meals can maintain a better activity state into the kiln to take part in the solid state reactions. Originality In order to study influences of different decomposition temperatures on the activity of the formed CaO during solid state reactions,the amount of free CaO generated through the reactions between the decomposition products of limestone and SiO_2 are determined by chemical analysis.The less the amount of free CaO.the more the corresponding production-amount of solid-phase reaction.So different activity of freshly generated CaO with SiO_2 is firstly originality. CaO reacts with water to develop hydration reaction immediately,gives off heat. Conductive microcalorimeter is a state-of-the-art instrument to study the hydration heat, reaction rate which can describe the whole process of the hydration very completely is proportional to the instantaneous reaction heat power at constant temperature.CaO under various calcinating conditions are weighed,fixed water-cement ratio is selected, hydration exothermic rates are determined by the 8-channel calorimeter.So the activity of freshly generated CaO are determinated by 8-channel conductive microcalorimeter is second originality.
decomposition of limestone;;solid state reaction;;decomposition temperature;;activity of calcium oxides
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