自蔓延法铝热还原氧化锆的研究
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摘要
研究采用以ZrO_2-Al-Mg-Fe_2O_3-SiO_2为反应原料直接还原ZrO_2。该方法以铝热还原ZrO_2为基础,并结合了自蔓延反应的特点。研究涉及了该体系的热效应、渣金分离、渣和金属物相构成、金属微观形貌和组成等。绝热温度计算表明, ZrO_2-Al-Mg-Fe_2O_3-SiO_2体系能满足自蔓延反应的内部温度要求。单位质量热效应的计算表明,体系中加入Fe_2O_3能有效地提高反应体系的放热量。差热分析(DTA)显示:与ZrO_2-Al体系相比, ZrO_2-Al-Fe_2O_3体系在631℃下存在明显放热峰,表明Al与Fe_2O_3反应放出高热量为ZrO_2直接还原及渣金分离提供热能和温度条件。ZrO_2-Al-Mg-Fe_2O_3-SiO_2体系直接还原ZrO_2得到了以Zr为主要成分的金属,实现了渣金分离。扫描电镜/能谱分析(SEM/EDS)显示:金属球中各部分分层存在,各层间的Zr和Fe的含量存在明显差异,其中富锆相以树枝状结晶析出。惰气熔融红外吸收法分析表明,金属产物氧含量仅为0.024%(质量分数)。该研究为直接还原ZrO_2制备锆合金和制备高纯金属锆方法提供了支撑。
The direct reduction of ZrO_2 based on the aluminum thermal reduction was studied, which combined the advantages of the self-propagating reaction. ZrO_2, Al, Mg, Fe_2O_3 and SiO_2 were used as raw materials. The thermal effect of the system, separation and composition of slag and metal phase, metal microstructure and oxygen content of the metal were involved. The thermal calculation result showed that the addition of Fe_2O_3 could improve the heat release and ensure the self-propagating reaction in ZrO_2-Al-Mg-Fe_2O_3-SiO_2 system. The differential thermal analysis(DTA) results showed that the ZrO_2-Al-Fe_2O_3 system exhibited a significant exothermic peak compared with ZrO_2-Al systemat 631 ℃, due to the reaction of Al and Fe_2O_3, and the conditions of direct reduction of ZrO_2 and the separation of slag and metal were ensured by heat release. The metal with Zr as the main component had been produced in the ZrO_2-Al-Mg-Fe_2O_3-SiO_2 system, and the separation of slag and metal were also achieved. The scanning electron microscope/energy dispersive spectroscope(SEM/EDS) results showed that there were some layers in the metal sphere, and the contents of Zr and Fe showed a significant difference between different layers, which was due to that the zirconium-rich phase in the metal product was preferentially precipitated as dendritic crystals. And the oxygen content of the metal reached 0.024 %(mass fraction). This study showed the possibility on the preparation of zirconium alloy or high purity zirconium by direct reduction of ZrO_2.
The direct reduction of ZrO_2 based on the aluminum thermal reduction was studied, which combined the advantages of the self-propagating reaction. ZrO_2, Al, Mg, Fe_2O_3 and SiO_2 were used as raw materials. The thermal effect of the system, separation and composition of slag and metal phase, metal microstructure and oxygen content of the metal were involved. The thermal calculation result showed that the addition of Fe_2O_3 could improve the heat release and ensure the self-propagating reaction in ZrO_2-Al-Mg-Fe_2O_3-SiO_2 system. The differential thermal analysis(DTA) results showed that the ZrO_2-Al-Fe_2O_3 system exhibited a significant exothermic peak compared with ZrO_2-Al systemat 631 ℃, due to the reaction of Al and Fe_2O_3, and the conditions of direct reduction of ZrO_2 and the separation of slag and metal were ensured by heat release. The metal with Zr as the main component had been produced in the ZrO_2-Al-Mg-Fe_2O_3-SiO_2 system, and the separation of slag and metal were also achieved. The scanning electron microscope/energy dispersive spectroscope(SEM/EDS) results showed that there were some layers in the metal sphere, and the contents of Zr and Fe showed a significant difference between different layers, which was due to that the zirconium-rich phase in the metal product was preferentially precipitated as dendritic crystals. And the oxygen content of the metal reached 0.024 %(mass fraction). This study showed the possibility on the preparation of zirconium alloy or high purity zirconium by direct reduction of ZrO_2.
引文
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[13] Yi H C,Moore J J.Self-propagating high-temperature (combustion) synthesis (SHS) of powder-compacted materials[J].Journal of Materials Science,1990,25(2):1159.
[14] Xiao X H,Liu M Y,Luo F Y.Experimental study on aluminum-iron process for high-ferrous iron smelting [J].Iron and Vanadium Titanium,2001,22 (4):47.(肖翔鸿,刘名扬,罗发应.铝热法冶炼高钛铁工艺试验 [J].钢铁钒钛,2001,22(4):47.)
[15] Xu L,Lan P X,Yuan Y Y.Study on the new technology of high grade titanium iron production [J].South China Metal,2008,(2):4.(许磊,竺培显,袁宜耀.高品位钛铁生产新工艺的研究与探讨 [J].南方金属,2008,(2):4.)
[2] Bao Morigengaowa.Study on Preparation of Aluminum-Zirconium Alloy by Molten Salt Electrolysis [D].Shenyang:Northeastern University,2015.1.(包莫日根高娃.熔盐电解法制备铝锆合金的研究 [D].沈阳:东北大学,2015.1.)
[3] Wu Y K,Li Q B,Xu Z G,Wang L J,Xiong B K.Preparation of metal zirconium [J].Chinese Journal of Rare Metals,2009,33(4):462.(吴延科,李庆彬,徐志高,王力军,熊炳昆.金属锆的制备方法 [J].稀有金属,2009,33(4):462.)
[4] Zhe X,Dioka C A,Hendry A.Aluminothermic reduction of zirconia [J].Journal of the European Ceramic Society,2005,25(5):695.
[5] Leverkoehne M,Janssen R,Claussen N.Phase development of ZrxAly-Al2O3,composites during reaction sintering of Al/ZrO2/Al2O3,powder mixtures [J].Journal of Materials Science Letters,2002,21(2):179.
[6] Nes E.Precipitation of the metastable cubic Al3Zr-phase in subperitectic Al-Zr alloys [J].Acta Metallurgica,1972,20(4):499.
[7] Vecchio K S,Williams D B.Convergent beam electron diffraction study of Al3Zr in Al-Zr and Al-Li-Zr alloys [J].Acta Metallurgica,1987,35(12):2959.
[8] Agafonov S N,Krasikov S A,Ponomarenko A A,Ovchinnikova L.Phase relations in the aluminothermic reduction of ZrO2 [J].Inorganic Materials,2012,48(8):813.
[9] Samsonov G V,Podergin V A.Metallothermic processes in chemistry and metallurgy [A].Proceedings of the Conference on Metallothermic Processes in Chemistry and Metallurgy [C].1971.5.
[10] Agafonov S N,Krasikov S A,Zhidovinova S V,Ponomarenko A A.Metallothermic reduction of zirconium from oxides [J].Tsvetnaya Metally,2013,(12):66.
[11] Flores A,Juarez R,Torres J,Ayala J.A kinetic study on the aluminothermic reduction of ZrO2 [J].Journal of Engineering and Technology,2012,2(1):17.
[12] Chumarev V M,Mansurova A N,Gulyaeva R I.Specific features of the initial stages of the aluminothermicreduction of zirconium from ZrO2 [J].Russian Metallurgy (Metally),2015,(9):719.
[13] Yi H C,Moore J J.Self-propagating high-temperature (combustion) synthesis (SHS) of powder-compacted materials[J].Journal of Materials Science,1990,25(2):1159.
[14] Xiao X H,Liu M Y,Luo F Y.Experimental study on aluminum-iron process for high-ferrous iron smelting [J].Iron and Vanadium Titanium,2001,22 (4):47.(肖翔鸿,刘名扬,罗发应.铝热法冶炼高钛铁工艺试验 [J].钢铁钒钛,2001,22(4):47.)
[15] Xu L,Lan P X,Yuan Y Y.Study on the new technology of high grade titanium iron production [J].South China Metal,2008,(2):4.(许磊,竺培显,袁宜耀.高品位钛铁生产新工艺的研究与探讨 [J].南方金属,2008,(2):4.)