| α-磷酸锆的制备及热分解非等温动力学研究 |
| STUDY ON THE PREPARATION AND NON-ISOTHERMAL KINETICS OF THERMAL DECOMPOSITION OF α-ZIRCONIUM PHOSPHATE |
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| 摘要: 采用改进的直接沉淀氟配位法，在常温常压下制备出了α-磷酸锆(α-ZrP)，XRD结果表明它的层间距为0.765 nm，结晶度较好，并以热重分析法(TG)为手段，对α-ZrP的热分解过程和非等温热分解动力学机理进行了研究。结果显示，在线性升温速率为10℃/min时，α-ZrP在131℃开始脱结晶水；脱去结晶水后形成的Zr(HPO4)2在453℃进行磷羟基缩合，至720℃完全分解为ZrP2O7。脱结晶水和分解过程的失重分别为6.24%和5.64%，与理论值基本相符。动力学研究确定了Zr(HPO4)2分解反应属于Avrami-Erofeev的成核和核成长为控制步骤的Al机理，热分解反应表观活化能为165.6 kJ/mol, 频率因子为3.50×107 s-1。 |
| 关键词: α-磷酸锆 热分解 动力学 机理 |
| 基金项目: |
| Abstract: Crystalline sample of α-Zr(HPO4)2·H2O(α-ZrP) has been prepared by a modified method involving complexion of zirconium with fluoride ions in a glass vessel, followed by reaction with phosphoric acid at room temperature. The product is highly crystalline with an interlayer spacing of 0.765 nm. The kinetic behavior and process of thermal decomposition of α-zirconium phosphate has been studied by thermogravimetry at linearly increasing temperature. It is illustrated that the crystal water is dehydrated and anhydrous zirconium phosphate is formed at below 453℃. Anhydrous zirconium phosphate is decomposed into ZrP2O7 completely at 720℃. The weight losses of dehydration and decomposition were 6.24% and 5.64% respectively, which conformed with theoretical values. The decomposition reaction of anhydrous zirconium phosphate is controlled by Avrami-Erofeev random nucleation and subsequent growth mechanism(A1). Accordingly, kinetic equation can be deduced as, dα/dt=3.50×107·e-165.6×103/RT·(1-α). These results are in good agreement with experiment results. |
| Keywords: α-zirconium phosphate thermal decomposition kinetics mechanism |
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| 摘要点击次数: 1363 |
| 全文下载次数: 1895 |
| 李峰,何静,杜以波,D.G.Evans,王作新,段雪.α-磷酸锆的制备及热分解非等温动力学研究[J].无机化学学报,1999,15(1):55-60. |
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