KINETICS OF THERMAL DECOMPOSITION OF AMMONIUM THIOTUNGSTATE OF
GRANULARITY62~72μm IN N2
GRANULARITY62~72μm IN N2
(Northeastern University, Shenyang110006)
Abstract: The thermal decomposition mechanism of ammonium thiotungstate of granularity 62~74μm in N2was investigated by means of DTA and XRD methods. The thermal decomposition reaction occurs in three steps: (NH4)2WS4H2O→(NH4)2WS4+H2O→2NH3+H2+2S+WS2→2NH3+H2S+S+WS2. The thermal decomposition activation energy and orders of (NH4)2WS4H2O in granularity of 62~74μm in three steps were calculated according to Kissinger, Freeman-Carrol, Coasts-Redfern methods from the DTA curves. The value of activation energy and the orders of reactions is 551.87 kJ/mol and 1.4 in the first step, 125.65 kJ/mol and 0.52 in the second step as well as 277.69kJ/mol and 0.8 in the third step respectively. The reaction rate in every step has also been given.
Key words: (NH4)2WS4·H2O thermal decomposition kinetics N2 DTA XRD