Non-isothermal kinetics studies on the thermal decomposition of zinc hydroxide carbonate

作者：Li ZJ^*; Shen XQ; Feng X; Wang PY; Wu ZS

来源：Thermochimica Acta, 2005, 438(1-2): 102-106.

DOI：10.1016/j.tca.2005.08.026

• thermal decomposition
• non-isothermal kinetics
• zinc hydroxide carbonate

Zinc hydroxide carbonate precursor, Zn4CO3(OH)6 center dot H2O, was synthesized from zinc sulfate using ammonium carbonate as a precipitating agent. Thermogravimetry (TG), differential scanning calorimetry (DSC), transmission electronic microscopy (TEM), infrared spectrum (IR) and X-ray diffraction (XRD) were used to characterize the precursor and the decomposed product. Non-isothermal kinetics of the thermal decomposition of zinc hydroxide carbonate were studied in nitrogen. Based on which, the kinetic parameters were obtained through mode-free method and the thermal decomposition mechanism was derived by mains of non-linear regression. The results show that the decomposition of zinc hydroxide carbonate acts as a double-step reaction, A <-->(D2) B -->(Fn) C: a reversible reaction of two-dimensional diffusion (D2), with E1 = 202 kJ mol(-1), lg(A1/s(-1)) = 22.1, is followed by an irreversible one of nth-order reaction (Fn) with n = 0.51, E2 = 129 kJ mol(-1), lg(A2/s(-1)) = 10.5, and the decomposition of Zn4CO3(OH)(6)center dot H2O to ZnO is accompanied by the change in particle morphology and particle size.

• 出版日期2005-11-1
• 单位河南大学; 洛阳师范学院; 郑州大学