Partial thermal reduction of ammonium paratungstate tetrahydrate

被引：32
|
作者：
Szilagyi, I. M.
Madarasz, J.
Hange, F.
Pokol, G.
机构：
[1] Budapest Univ Technol & Econ, Inst Gen & Analyt Chem, H-1111 Budapest, Hungary
[2] GE Hungary ZRt, GE Consumer & Ind Lighting, H-1340 Budapest, Hungary
来源：
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY | 2007年 / 88卷 / 01期
关键词：
FTIR spectroscopy; mass spectrometry; simultaneous TG; DTA; tungsten; X-ray diffraction;
D O I：
10.1007/s10973-006-8078-0
中图分类号：
O414.1 [热力学];
学科分类号：
摘要：
Thermal decomposition of ammonium paratungstate tetrahydrate, (NH4)(10)[H2W12O42]center dot 4H(2)O has been followed by simultaneous TG/DTA and online evolved gas analysis (TG/DTA-MS) in flowing 10% H-2/Ar directly up to 900 degrees C. Solid intermediate products have been structurally evaluated by FTIR spectroscopy and powder X-ray diffraction (XRD). A previously unexplained exothermic heat effect has been detected at 700-750 degrees C. On the basis of TG/DTA as well as H2O and NH3 evolution curves and XRD patterns, it has been assigned to the formation and crystallization heat of gamma-tungsten-oxide (WO2.72/W18O49) from beta-tungsten-oxide (WO2.9/W20O58) and residual ammonium tungsten bronze.
引用
收藏
页码：139 / 144
页数：6
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