KINETICS　OF　THERMAL　DECOMPOSITION　OF　AMMONIUM　THIOTUNGSTATE　OF　GRANULARITY　62～72　μm　IN　N_2

ＫＩＮＥＴＩＣＳＯＦＴＨＥＲＭＡＬＤＥＣＯＭＰＯＳＩＴＩＯＮＯＦＡＭＭＯＮＩＵＭＴＨＩＯＴＵＮＧＳＴＡＴＥＯＦＧＲＡＮＵＬＡＲＩＴＹ６２～７２μｍＩＮＮ_２ＸｉｎｇＰｅｎｇｆｅｉ；ＺｈａｉＹｕｃｈｕｎ；ＴｉａｎＹａｎｗｅｎ；ＣｈａｏＹｕｅｓｈｅｎｇ；?..

The thermal decomposition mechanism of ammonium thiotungstate of granularity 62～74 μm in N2 was 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 ～ 74 μm 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 551.87kJ/mol and 1.4 in the first step, 125.65 kJ/mol and 0.52 in the second step as well as 277.69 kJ/mol and 0.8 in the third step respectively. The reaction rate in every step has also been given.