不同单斜仲钨酸铵在惰性气体中的热分解研究
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摘要
研究了两种不同APT样品的分解过程。在25~560℃范围内进行了TG-DSC试验,测定了各阶段反应的激活能。在DSC各峰值温度进行了煅烧试验,并用XRD和SEM研究各阶段反应产物的结构和显微形貌。结果显示,分解过程除结晶水脱附、脱氨、铵钨青铜、蓝色氧化钨四个阶段外,在560℃存在晶型转变第五个阶段。APT原料的孔隙率越高、费氏粒度和松装密度越低,各阶段反应激活能越低。
In this paper the decomposition processes of two different APT samples were investigated. The activation energies of all reactions were estimated by TG-DSC experiments in the range of 25 to 560 ℃. Calcination experiments were carried out at each reaction temperature according to DSC, and the structure and the micro-morphology of reaction products were detected by XRD and SEM. The result shows that, in addition to the four decomposition stages of crystal water release, ammoniarelease, ammoniumtungsten bronze and blue tungsten oxide,there is the fifth stage of crystal transformation at 560 ℃. The reaction activation energy of all the stages reduces with the increase of porosity of the APT raw materials and the decrease of the Fischer particle size and the bulk density.
In this paper the decomposition processes of two different APT samples were investigated. The activation energies of all reactions were estimated by TG-DSC experiments in the range of 25 to 560 ℃. Calcination experiments were carried out at each reaction temperature according to DSC, and the structure and the micro-morphology of reaction products were detected by XRD and SEM. The result shows that, in addition to the four decomposition stages of crystal water release, ammoniarelease, ammoniumtungsten bronze and blue tungsten oxide,there is the fifth stage of crystal transformation at 560 ℃. The reaction activation energy of all the stages reduces with the increase of porosity of the APT raw materials and the decrease of the Fischer particle size and the bulk density.
引文
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[2] JORGENSEN M J,KHAN K S. Use of tungsten to reduce hand-arm vibration exposure in aircraft manufacturing[C]. Human Factors&Ergonomics Society Meeting,2008:1045-1048.
[3] PALACIOS T,REISER J,HOFFMANN J,et al. Microstructural and mechanical characterization of annealed tungsten(W)and potassium-doped tungsten foils[J]. International Journal of Refractory Metals and Hard Materials,2015,48:145-149.
[4]张启修,赵秦生.钨钼冶金[M].北京:冶金工业出版社,2005:1-574.
[5] KALPAKLI A O,ARABACI A,KAHRUMAN C,et al. Thermal decomposition of ammonium paratungstate hydrate in air and inert gas atmospheres[J]. International Journal of Refractory Metals&Hard Materials,2013,37(2):106-116.
[6]王雪晴,杨建参,刘山宇,等.仲钨酸铵的热分解过程研究[J].中国钨业,2014,29(2):32-36.WANG Xueqing,YANG Jiancan,LIU Shanyu,et al. Thermal decomposition process of ammonium paratungstate[J]. China Tungsten Industry,2014,29(2):32-36.
[7] FAIT M J G,LUNK H J,FEIST M,et al. Thermal decomposition of ammonium paratungstatetetrahydrate under non-reducing conditions:Characterization by thermal analysis,X-ray diffraction and spectroscopic methods[J]. ThermochimicaActa,2008,469(1/2):12-22.
[8] LUNK H J,ZIEMER B,SALMEN M,et al. What is behind‘tungsten blue oxides’?[J]. International Journal of Refractory Metals&Hard Materials,1993,12(1):17-26.
[9] KISSINGER H E. Variation of peak temperature with heating rate in differential thermal analysis[J]. Journal of Research of the National Bureau of Standards,1956,57(4):217-221.
[10]曾文明,陈启元,李元高.仲钨酸铵热分解动力学研究[J].稀有金属,1994,9(1):9-13.ZENG Wenming,CHEN Qiyuan,LI Yuangao. Investigation on the decomposition dynamics of ammonium paratungstate[J]. Rare Metals,1994,9(1):9-13.
[11] MANSOUR S AA,MOHAMED M A,ZAKI M I. Thermaldecomposition and the creation of reactive solid-surfaces. 5. the genesis course of the WO3 catalyst from its ammonium paratungstate,precursor[J]. ThermochimicaActa,1988,129(2):187-196.
[12] FRENCH G J,SALE F R. A re-investigation of the thermal decomposition of ammonium paratungstate[J]. Journal of Materials Science,1981,16(12):3427-3436.