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通过改变添加剂种类和反应温度,研究了钙盐焙烧中钒钙二元系化合物的反应过程,研究发现,钙盐添加剂为纯CaO 和纯CaCO3时发生的反应步骤一致,初始反应为在625℃左右V2 O5与钙盐反应生成CaV2 O6,同时CaV2 O 6开始与钙盐结合生成Ca2 V2 O 7；后续反应为 CaV2 O 6继续与钙盐反应生成 Ca2 V2 O 7.两种钙盐反应的区别在于,CaCO3的初始反应过程中生成 CaV2 O6的同时还伴有 Ca2 V2 O7生成,后续反应开始的温度为708℃；CaO 的初始反应过程中只有少量 Ca2 V2 O7生成,后续反应开始的温度为777℃.两种钙盐添加剂焙烧产物的转浸率分别为73％和94．5％,通过对产物的微观结构分析,其差异可能的原因为,当添加剂为 CaO 时,随着反应的进行,产物的表面会变得非常致密,影响反应的继续进行.当添加剂为 CaCO3时,反应过程中产生的CO2向外扩散,使产物疏松多孔,有利于反应传质,同时增大反应物接触面积,使反应速度更快,反应也更加完全.因此使用CaCO3作为钙盐添加剂能得到更好的反应效果.

In this work,we studied the roasting process of calcium vanadium compound with different additives and different temperature conditions.It is found that,the reaction steps with CaO additive is as the same as those with CaCO3 .The first step is that when the temperature is 625 ℃,V2 O5 reacts with calcium to form a large amount of CaV2 O6 and some of CaV2 O6 starts to react with calcium.After then,lots of Ca2 V2 O7 formed with the reaction of CaV2 O6 and calcium.The difference between two additives is that with CaCO3 additive, both of CaV2 O6 and Ca2 V2 O7 are formed during the initial reaction and the temperature to react next step is 708 ℃.While with CaO additive,there are only a few Ca2 V2 O7 formed and the subsequent reaction temperature is 777 ℃.The experimental data shows that the leaching rate of two calcium additives are 73% and 94.5%,re-spectively.By analyzing the micro structure of reaction products,we found that with the CaO additive,the products become so compact that it affects the reaction with CaO.When the additive is CaCO3 ,it is a favorable response to the mass transfer that CO2 gas,formed during the reaction,diffuses outward and tiny interspace form inside the materials.Moreover,increasing the reaction area makes the reaction speed faster and reaction more entirely conducted.Therefore,it will get much better to the reaction in the roasting process when the ad-ditive is CaCO3 .