Thermal decomposition and non-isothermal kinetic evaluation of magnesium chloride hexammoniate (MgCl2·6NH3) were studied with thermogravimetric analysis (TGA).The decomposition mechanism of MgCl2·6NH3 was investigated at five heating rates of 4

7

10

13 and 16 K·min-1 with an air flow of 50 ml·min-1.The results showed that the thermal decomposition of MgCl2·6NH3 was divided into three stages.A globally optimized iterative iso-conversion method was proposed to calculate the activation energy of thermal decomposition.The calculated activation energies of MgCl2·6NH3 at each thermal decomposition stage were 51.38

64.70 and 73.55 kJ·mol-1 respectively.The most probable decomposition mechanism functions and pre-exponential factors corresponding to each stage of thermal decomposition of MgCl2·6NH3 were derived.The thermal decomposition of MgCl2·6NH3 at the first stage belonged to the phase boundary reaction (n=1/4)

and the corresponding pre-exponential factor (A) was 3.281×105 s-1 .The thermal decomposition mechanism of MgCl2·6NH3 at the second stage belonged to the nucleation and growth mechanism (n=1.8)

and A was 5.624×106 s-1.The thermal decomposition mechanism of MgCl2·6NH3 at the third stage belonged to the chemical reaction mechanism (n=1.5)

and A was 5.862×105 s-1.