THERMAL DECOMPOSITION OF THREE COMMERCIAL POLYPHASE AMMONIUM MOLYBDATE

ＴＨＥＲＭＡＬＤＥＣＯＭＰＯＳＩＴＩＯＮＯＦＴＨＲＥＥＣＯＭＭＥＲＣＩＡＬＰＯＬＹＰＨＡＳＥＡＭＭＯＮＩＵＭＭＯＬＹＢＤＡＴＥＹｉｎＺｈｏｕｌａｎ；ＬｉＸｉｎｈａｉ；ＺｈｏｕＧｕｉｚｈｉ；ＺｈａｏＱｉｎｓｈｅｎｇ；ＣｈｅｎＳｈａｏｙｉ（Ｄｅｐａｒｔｍ...

DTA/TGA and XRD were employed to study the thermal decomposition of three commercial polyphase ammonium molybdate mixtures. A series of intermediate phases of ammonium molybdates, in which the content of molybdenum increases with the raise of temperature, were identified during the course of heating. The main decomposition reactions occurred in steps as follows: (1) at 110 degrees C, (NH4)(6)Mo7O24. 4H(2)O decomposed into (NH4)(4)Mo5O17; (2) at 220 degrees C, (NH4)(4)Mo5O17 decomposed into (NH4)(2)Mo4O13; (3) at 290 degrees C, (NH4)(2)Mo4O13 Or beta- (NH4)(2)Mo4O13 decomposed into MoO3.