熔盐法制备镁铬尖晶石及在尾气净化器中的应用
|
摘要
熔盐合成法是近代发展起来的一种无机材料合成方法。它采用一种或几种低熔点的盐类作为反应介质,在高温熔融盐中完成合成反应,然后采用合适的溶剂将盐类溶解,经过滤、洗涤得到合成产物。由于熔盐合成法具有工艺简单、成本低廉、合成温度低、保温时间短、合成产物的化学成分稳定均匀等优点,因而在合成高熔点氧化物粉体和电子陶瓷粉体及其它功能粉体材料等领域广泛应用。
本文在NaCl、KCl熔盐介质中合成了镁铬尖晶石粉体,研究了原料种类、热处理温度和保温时间、熔盐的种类对镁铬尖晶石粉体性能的影响,同时对镁铬尖晶石应用于汽车尾气净化器载体进行了研究。研究发现,氧化铬、结晶氯化铬、结晶硝酸铬均能与结晶氯化镁和碳酸钙原料反应生成镁铬尖晶石,MgCl2·6H2O、CaCO3、Cr2O3、NaCl、KCl原料在900℃下保温5小时热处理制备的镁铬尖晶石晶体分布最为均匀,大部分为八面体形貌,晶体生长完全,Cr(NO3)3.9H2O和CrCl3.6H2O等铬盐制备的镁铬尖晶石,除了少部分呈八面体形貌外,大部分生长不完整,为形状不规则的镁铬尖晶石颗粒；随着热处理温度的升高和保温时间的延长,镁铬尖晶石晶体的结晶度有所提高,颗粒粒径增大；NaCl熔盐介质中,镁铬尖晶石晶体生长的表观活化能Ea=10.01 KJ/mol。所制备的蜂窝型镁铬尖晶石多孔陶瓷作为汽车尾气处理用催化剂载体在形状、网格尺寸方面均能达到使用标准,所制备的镁铬尖晶石多孔陶瓷具有多孔隙、孔径分布均匀、比表面积大等优点,可以很均匀地吸附和储存催化剂,为达到理想的净化效果创造了条件。
Molten salt method is recently developed as a novel synthetic method for inorganic materials. Based on one or more low melting point salts as a reaction medium, which can be dissolved by the appropriate solvent, the reaction is easily carried out via the media and pure product can be obtained after filtering and washing. Due the advantages of the simple process, low cost and synthetic temperature, short reaction time and high stability in chemical compositions, molten salt method has been widely applied in different fields, such as in the synthesis of high melting point oxide powders, electronic ceramic powders and other functional powder materials.
MgCr2O4 spinel powders were synthesized in NaCl and KCl molten salt media. The effects of different raw materials, such as heating temperature, holding time and different molten salt kinds on the performances of the products have been studied. The results indicated shows that both the chromic oxide and chromic salt can be combined with crystal magnesium and calcium carbonate to produce octahedral MgCr2O4 spinel. The materials--MgCl2·6H2O、CaCO3、Cr2O3、NaCl、KCl being heated under 900℃for 5hours, the crystal size distribution of MgCr2O4 spinel becomes equal in a octahedral form and such crystals grow complete. By contrast, the crystals of MgCrO4 spinel produced by Cr(NO3)3.9H2O and CrCl3.6H2O become octahedral, incomplete and irregular in form. With increase in heating process temperature and delay in soaking time, the crystallinity of MgCr2O4 spinel improves and crystal size increases, too. And MgCr2O4 spinel growth features Ea=10.01 KJ/mol in medium of NaCl fused salt. Through molten-salt method the produced cellular MgCr2O4 spinel ceramics can be used as the carrier of automobile exhaust katalyst, standard both in form and in grid size. And the cellular MgCr2O4 spinel has the advantage of more pores, even pore width and large surface area. Therein, the celluar magne siochromic can so evenly absorb and preserve the automobile exhaust katalyst as to provide conditions for perfect exhaust purified effect.
本文在NaCl、KCl熔盐介质中合成了镁铬尖晶石粉体,研究了原料种类、热处理温度和保温时间、熔盐的种类对镁铬尖晶石粉体性能的影响,同时对镁铬尖晶石应用于汽车尾气净化器载体进行了研究。研究发现,氧化铬、结晶氯化铬、结晶硝酸铬均能与结晶氯化镁和碳酸钙原料反应生成镁铬尖晶石,MgCl2·6H2O、CaCO3、Cr2O3、NaCl、KCl原料在900℃下保温5小时热处理制备的镁铬尖晶石晶体分布最为均匀,大部分为八面体形貌,晶体生长完全,Cr(NO3)3.9H2O和CrCl3.6H2O等铬盐制备的镁铬尖晶石,除了少部分呈八面体形貌外,大部分生长不完整,为形状不规则的镁铬尖晶石颗粒；随着热处理温度的升高和保温时间的延长,镁铬尖晶石晶体的结晶度有所提高,颗粒粒径增大；NaCl熔盐介质中,镁铬尖晶石晶体生长的表观活化能Ea=10.01 KJ/mol。所制备的蜂窝型镁铬尖晶石多孔陶瓷作为汽车尾气处理用催化剂载体在形状、网格尺寸方面均能达到使用标准,所制备的镁铬尖晶石多孔陶瓷具有多孔隙、孔径分布均匀、比表面积大等优点,可以很均匀地吸附和储存催化剂,为达到理想的净化效果创造了条件。
Molten salt method is recently developed as a novel synthetic method for inorganic materials. Based on one or more low melting point salts as a reaction medium, which can be dissolved by the appropriate solvent, the reaction is easily carried out via the media and pure product can be obtained after filtering and washing. Due the advantages of the simple process, low cost and synthetic temperature, short reaction time and high stability in chemical compositions, molten salt method has been widely applied in different fields, such as in the synthesis of high melting point oxide powders, electronic ceramic powders and other functional powder materials.
MgCr2O4 spinel powders were synthesized in NaCl and KCl molten salt media. The effects of different raw materials, such as heating temperature, holding time and different molten salt kinds on the performances of the products have been studied. The results indicated shows that both the chromic oxide and chromic salt can be combined with crystal magnesium and calcium carbonate to produce octahedral MgCr2O4 spinel. The materials--MgCl2·6H2O、CaCO3、Cr2O3、NaCl、KCl being heated under 900℃for 5hours, the crystal size distribution of MgCr2O4 spinel becomes equal in a octahedral form and such crystals grow complete. By contrast, the crystals of MgCrO4 spinel produced by Cr(NO3)3.9H2O and CrCl3.6H2O become octahedral, incomplete and irregular in form. With increase in heating process temperature and delay in soaking time, the crystallinity of MgCr2O4 spinel improves and crystal size increases, too. And MgCr2O4 spinel growth features Ea=10.01 KJ/mol in medium of NaCl fused salt. Through molten-salt method the produced cellular MgCr2O4 spinel ceramics can be used as the carrier of automobile exhaust katalyst, standard both in form and in grid size. And the cellular MgCr2O4 spinel has the advantage of more pores, even pore width and large surface area. Therein, the celluar magne siochromic can so evenly absorb and preserve the automobile exhaust katalyst as to provide conditions for perfect exhaust purified effect.
引文
[1]段淑贞,孙家跃,乔芝郁.熔盐化学[M].北京：冶金工业出版社,1990：29-30.
[2]谢刚.熔融盐理论与应用[M].北京：冶金工业出版社,1998：1-7.
[3]Arendt R H. Liquid-phase Sintering of Magnetically Isotropic and Anise by the Reaction of BaFe2O4 with Fe2O3 [J]. Journal Solid State Chem.1973,8(4):339-347.
[4]Arendt R.H, Rosolowski J H, Szymaszek J W. Lead Zirconate Titanate Ceramics from Molten Salt Solvent Synthesized Powders [J]. Materials Research Bulletin,1979, (14):703-709
[5]Hsiang H I, Chang C H. Molten Salt Synthesis and Magnetic Properties of 3BaO2·CoO·12Fe2O3 Powder [J]. Journal of Magnetism and Magnetic Materials,2004, 278(1-2):218-222.
[6]Mishra B, Olson D L. Molten Salt Applications in Materials Processing [J]. Journal of Physics and Chemistry of Solids,2005,66(2):396-401.
[7]田中青,刘韩星,余洪滔等.微波介质陶瓷粉体的合成方法研究[J].材料导报,2003,17(12)：48-51.
[8]宋煜听,李承恩,晏海学.熔盐法合成SrBi2Ta209粉体[J].无机材料学报,2002,17(1)：145—148.
[9]郝华,罗大兵,刘韩星等.熔盐法合成SrBi4Ti4O15片状铁电陶瓷粉末[J].武汉理工大学学报,2004,26(1)：4-6.
[10]Liu S F, Fu W T. Synthesis of Superconducting Ba1-xKxBiO3 by a Modified Molten Salt Process [J]. Materials Research Bulletin,2001,36(7-8):1505-1512.
[11]K.S. Tan, M.V. Reddy, G.V. Subba, et al. High Performance LiCoO2 by Molten Salt Synthesis for Li-ion Batteries [J]. Journal of powder source,2005,147:241-248.
[12]Thirumal M, Jain P A, Ganguli K. Molten Salt Synthesis of Complex Perovskite-related Dielectric Oxides [J]. Materials Chemistry and Physics,2001,70(1):7-11.
[13]张冰,曹传宝,许亚杰等.熔盐法合成莫来石晶须[J].无机化学学报,2005,21(2)：277-280.
[14]Kim J H, Myung S T, Sun Y K. Molten Salt Synthesis of LiNi0.5Mn1.5O4 Spinel for 5V Class Cathode Material of Li-ion Secondary Battery [J]. Electrochemical Acta,2004,49(2): 219-227.
[15]Hashimoto S, Zhang S W, Lee W E, et al. Synthesis of Magnesium Aluminate Spinel Platelets from α- Alumina Platelet and Magnesium Sulfate Precursors [J]. J Am Ceram Soc., 2003,86(11):1959-1961.
[16]Wang X, Song J, Gao L S, et al. Synthesis of Single Crystalline Layered Lithium Manganese Oxide Nanorods. [J]. Solid State Communications,2004,132(11):783-785.
[17]Wang X, Gao L S, Zhou F, et al. Large-Scale Synthesis of a-LiFeO2 Nanorods by Low-Temperature Molten Salt Synthesis Method [J]. Journal of Crystal Growth,2004, 265(1-2):220-223.
[18]Afanasiev P, Geanter C. Synthesis of Solid Materials in Molten Nitrates [M]. Coordination Chemistry Reviews,1998,178-180(2):1725-1752.
[19]Hashimoto S, Zhang S W, Lee W E, et al. Synthesis of Magnesium Aluminate Spinel Platelets from a-Al2O3 Platelet and Magnesium Sulfate Precursors [J]. J. Am Ceram Soc., 2003,86(11):1959-1961.
[20]朱伯铨,李雪冬.在硫酸钠熔盐中合成莫来石的热力学研究[J].硅酸盐学报,2006,34(1)：76-80.
[21]Docters T, Chovelon J M, Herrmann JM, et al. Syntheses of TiO2 Photocatalysis by the molten salts method:Application to the Photocatalysis degradation of Prosulfuron. Applied Catalysis B:Environmental,2004,50(4):219-224.
[22]Singh N B. Preparation of Metal Oxides and Chemistry of Oxides Ions in Nitrate [J]. Progress in Crystal Growth and Characterization of Materials,2002:183-188.
[23]Choo H S, Lee K Y, Kim Y S, et al. Synthesis of Ni3Al Intermetallic Powder in Eutectic Molten Salts [J]. Intermetallics,2005,13(2):157-161.
[24]Zhao J L, Cui L S, Gao W F, et al. Synthesis of NiTi Particles by Chemical Reaction in Molten Salts [J]. Intermetallics,2005,13(3-4):301.
[25]张克从,张乐惠.晶体化学[M].北京：科学出版社,1981：285—297.
[26]全跃主编.镁质材料生产与应用[M].北京：冶金工业出版社.
[27]黄卫国译.熔盐法合成纳米MgA12O4粉[J].耐火材料,2002,5：251.
[28]曹建,谢嘉宁,张业凤.熔盐法合成BaFe11Co0.5Ti0.5O19磁性粉体及其性能分析[J].功能材料,1996,27(5)：446-448.
[29]邓勇跃,汪厚植等.共沉淀法制备镁铬尖晶石粉体[J].无机盐工业,2005,(7)：32-35.
[30]黄爱红,沈德阳MgCr2O4的低温合成及其表征[J].无机盐工业,1992,(6)：11-14.
[31]王健东,潘波等.RH炉用高级镁铬砖的研究与侵蚀机理分析[J].钢,2007,23(4)：4-64
[32]李日升.镁铬尖晶石的制取及应用[J].中国搪瓷,2003,6：52-54
[33]胡庆福.镁化合物生产与应用[M].北京：化学工业出版社,2004
[34]Nitta K, Shau T M, Sugahara J. Flaky Aluminum Oxide and Pearlescent Pigments and Production Thereof. EP0763573A2,1997-03-19.
[35]Singh N B. Preparation of metal oxides and chemistry of oxides ions in nitrate. Progress in Crystal Growth and Characterization of Materials,2002:183-188.
[36]Mishra B, Olson D L. Molten Salt Applications in Materials Processing [J]. Journal of Physics and Chemistry of Solids,2005,66(2):396-401.
[37]徐曾启主编.炉外精炼[M].北京：冶金工业出版社,2002,3
[38]赵惠忠,张文杰,汪厚植等.高性能RH浸溃管浇注料的研究[J].武汉科技大学学报(自然科学版),2001,24(1)：27-30
[39]李颖,王宝琦等.RH炉用高性能电熔再结合镁铬砖的研制.耐火与石灰,2008,8(4)：1-4
[40]于仁红.铜转炉介质对镁铬耐火材料侵蚀机理的研究[D].硕士学位论文,2002,5
[41]P.Taskinen炼铜转炉中镁铬砖、渣、铜锍和铜之间的反应—有色冶炼用耐火材料[M].北京：冶金工业出版社,1984,332.
[42]Bhaduris S, Bhaduris S B., Microstructural and mechanical properties of nanocrystalline spinel and related composites [J]. Ceram Inter.,2002,28:152-158.
[2]谢刚.熔融盐理论与应用[M].北京：冶金工业出版社,1998：1-7.
[3]Arendt R H. Liquid-phase Sintering of Magnetically Isotropic and Anise by the Reaction of BaFe2O4 with Fe2O3 [J]. Journal Solid State Chem.1973,8(4):339-347.
[4]Arendt R.H, Rosolowski J H, Szymaszek J W. Lead Zirconate Titanate Ceramics from Molten Salt Solvent Synthesized Powders [J]. Materials Research Bulletin,1979, (14):703-709
[5]Hsiang H I, Chang C H. Molten Salt Synthesis and Magnetic Properties of 3BaO2·CoO·12Fe2O3 Powder [J]. Journal of Magnetism and Magnetic Materials,2004, 278(1-2):218-222.
[6]Mishra B, Olson D L. Molten Salt Applications in Materials Processing [J]. Journal of Physics and Chemistry of Solids,2005,66(2):396-401.
[7]田中青,刘韩星,余洪滔等.微波介质陶瓷粉体的合成方法研究[J].材料导报,2003,17(12)：48-51.
[8]宋煜听,李承恩,晏海学.熔盐法合成SrBi2Ta209粉体[J].无机材料学报,2002,17(1)：145—148.
[9]郝华,罗大兵,刘韩星等.熔盐法合成SrBi4Ti4O15片状铁电陶瓷粉末[J].武汉理工大学学报,2004,26(1)：4-6.
[10]Liu S F, Fu W T. Synthesis of Superconducting Ba1-xKxBiO3 by a Modified Molten Salt Process [J]. Materials Research Bulletin,2001,36(7-8):1505-1512.
[11]K.S. Tan, M.V. Reddy, G.V. Subba, et al. High Performance LiCoO2 by Molten Salt Synthesis for Li-ion Batteries [J]. Journal of powder source,2005,147:241-248.
[12]Thirumal M, Jain P A, Ganguli K. Molten Salt Synthesis of Complex Perovskite-related Dielectric Oxides [J]. Materials Chemistry and Physics,2001,70(1):7-11.
[13]张冰,曹传宝,许亚杰等.熔盐法合成莫来石晶须[J].无机化学学报,2005,21(2)：277-280.
[14]Kim J H, Myung S T, Sun Y K. Molten Salt Synthesis of LiNi0.5Mn1.5O4 Spinel for 5V Class Cathode Material of Li-ion Secondary Battery [J]. Electrochemical Acta,2004,49(2): 219-227.
[15]Hashimoto S, Zhang S W, Lee W E, et al. Synthesis of Magnesium Aluminate Spinel Platelets from α- Alumina Platelet and Magnesium Sulfate Precursors [J]. J Am Ceram Soc., 2003,86(11):1959-1961.
[16]Wang X, Song J, Gao L S, et al. Synthesis of Single Crystalline Layered Lithium Manganese Oxide Nanorods. [J]. Solid State Communications,2004,132(11):783-785.
[17]Wang X, Gao L S, Zhou F, et al. Large-Scale Synthesis of a-LiFeO2 Nanorods by Low-Temperature Molten Salt Synthesis Method [J]. Journal of Crystal Growth,2004, 265(1-2):220-223.
[18]Afanasiev P, Geanter C. Synthesis of Solid Materials in Molten Nitrates [M]. Coordination Chemistry Reviews,1998,178-180(2):1725-1752.
[19]Hashimoto S, Zhang S W, Lee W E, et al. Synthesis of Magnesium Aluminate Spinel Platelets from a-Al2O3 Platelet and Magnesium Sulfate Precursors [J]. J. Am Ceram Soc., 2003,86(11):1959-1961.
[20]朱伯铨,李雪冬.在硫酸钠熔盐中合成莫来石的热力学研究[J].硅酸盐学报,2006,34(1)：76-80.
[21]Docters T, Chovelon J M, Herrmann JM, et al. Syntheses of TiO2 Photocatalysis by the molten salts method:Application to the Photocatalysis degradation of Prosulfuron. Applied Catalysis B:Environmental,2004,50(4):219-224.
[22]Singh N B. Preparation of Metal Oxides and Chemistry of Oxides Ions in Nitrate [J]. Progress in Crystal Growth and Characterization of Materials,2002:183-188.
[23]Choo H S, Lee K Y, Kim Y S, et al. Synthesis of Ni3Al Intermetallic Powder in Eutectic Molten Salts [J]. Intermetallics,2005,13(2):157-161.
[24]Zhao J L, Cui L S, Gao W F, et al. Synthesis of NiTi Particles by Chemical Reaction in Molten Salts [J]. Intermetallics,2005,13(3-4):301.
[25]张克从,张乐惠.晶体化学[M].北京：科学出版社,1981：285—297.
[26]全跃主编.镁质材料生产与应用[M].北京：冶金工业出版社.
[27]黄卫国译.熔盐法合成纳米MgA12O4粉[J].耐火材料,2002,5：251.
[28]曹建,谢嘉宁,张业凤.熔盐法合成BaFe11Co0.5Ti0.5O19磁性粉体及其性能分析[J].功能材料,1996,27(5)：446-448.
[29]邓勇跃,汪厚植等.共沉淀法制备镁铬尖晶石粉体[J].无机盐工业,2005,(7)：32-35.
[30]黄爱红,沈德阳MgCr2O4的低温合成及其表征[J].无机盐工业,1992,(6)：11-14.
[31]王健东,潘波等.RH炉用高级镁铬砖的研究与侵蚀机理分析[J].钢,2007,23(4)：4-64
[32]李日升.镁铬尖晶石的制取及应用[J].中国搪瓷,2003,6：52-54
[33]胡庆福.镁化合物生产与应用[M].北京：化学工业出版社,2004
[34]Nitta K, Shau T M, Sugahara J. Flaky Aluminum Oxide and Pearlescent Pigments and Production Thereof. EP0763573A2,1997-03-19.
[35]Singh N B. Preparation of metal oxides and chemistry of oxides ions in nitrate. Progress in Crystal Growth and Characterization of Materials,2002:183-188.
[36]Mishra B, Olson D L. Molten Salt Applications in Materials Processing [J]. Journal of Physics and Chemistry of Solids,2005,66(2):396-401.
[37]徐曾启主编.炉外精炼[M].北京：冶金工业出版社,2002,3
[38]赵惠忠,张文杰,汪厚植等.高性能RH浸溃管浇注料的研究[J].武汉科技大学学报(自然科学版),2001,24(1)：27-30
[39]李颖,王宝琦等.RH炉用高性能电熔再结合镁铬砖的研制.耐火与石灰,2008,8(4)：1-4
[40]于仁红.铜转炉介质对镁铬耐火材料侵蚀机理的研究[D].硕士学位论文,2002,5
[41]P.Taskinen炼铜转炉中镁铬砖、渣、铜锍和铜之间的反应—有色冶炼用耐火材料[M].北京：冶金工业出版社,1984,332.
[42]Bhaduris S, Bhaduris S B., Microstructural and mechanical properties of nanocrystalline spinel and related composites [J]. Ceram Inter.,2002,28:152-158.