氧化铜对碳酸钙热分解动力学过程的影响

EFFECT OF COPPER OXIDE ON DECOMPOSITION KINETICS FOR CALCIUM CARBONATE

利用热重分析和差式扫描量热仪测定了CaCO3试样和在CaCO3试样中加入质量分数(下同)为1.0%CuO试样的热解动力学行为。应用CoatsandRedfern方程得出2种试样的活化能。X射线衍射扫描电镜、能谱分析等方法分析了掺入CuO后CaCO3在600～1100℃的7个温度保温0.5h所得分解产物的组成及微观形貌。结果表明:CuO的加入能降低CaCO3的分解温度,并降低其活化能值,当CuO掺入量为1%时,Ca CO3的起始分解温度和表观活化能比参比样分别下降了12℃和10kJ/mol。研究还表明:CuO与CaO反应形成了CaCu2O3和Ca2CuO32个中间化合物,该体系在1000～1050℃产生液相。

Decomposition kinetics of calcium carbonate doped with 1.0%CuO (in mass) and the sample without doping were studied by thermogravimetric analysis-differential scanning calorimetry. The apparent activation energy of the two samples was obtained by using Coats and Redfern equation. Furthermore, the mineral phases and morphology of the sample doped with 1.0%CuO and calcined at deferent temperatures from 600°C to 1100°C for 0.5 h were analyzed by X-ray diffraction, scanning electron microscope, and energy dispersive X-ray analysis. Results show that the doping of copper oxide can decrease the decomposition temperature and apparent activation energy of calcium carbonate. The temperature and activation energy of the calcium carbonate doped with 1%CuO are lower 12°C and 10 kJ/mol respectively, compared with the reference sample without doping. The results also show that the reaction between CuO and CaO can form two intermediate compounds, CaCu2O3 and Ca2CuO3, in which minor liquid phase is formed during 1000°C to 1050°C.