钙含量对钙钛锆石-钡硼硅酸盐玻璃陶瓷结构的影响
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摘要
采用熔融-热处理工艺制备SiO_2-Na_2O-B_2O_3-BaO-CaO-TiO_2-ZrO_2体系玻璃陶瓷,利用差热分析法(DTA)、傅氏转换红外线光谱分析仪(FTIR)、X射线衍射仪(XRD)、扫描电子显微镜(SEM)等技术手段研究了晶核剂(CaO、TiO_2和ZrO_2)总含量为45%时,不同钙含量(CaO∶TiO_2∶ZrO_2=x∶2∶1(摩尔比),x=0.5~6)对玻璃陶瓷晶相和显微结构的影响,并采用粉末静态浸泡法(PCT)测试了C-2(即x=2)玻璃陶瓷样品的抗浸出性能。结果表明:玻璃网络结构主要由[SiO_4]、[BO_3]和[BO_4]构成,随着Ca含量的增加,更多的B以[BO_4]加入玻璃网络中,玻璃转变温度Tg逐渐升高,放热峰温度逐渐降低,但峰强逐渐增高;x<2时,样品中除CaZrTi_2O_7晶相外还有其他晶相(如TiO_2和ZrO_2)出现;当x=2和4时,样品中只有单一的CaZrTi_2O_7晶相;x=6时,有星状的CaZrTi_2O_7和柱状的CaTiO_3晶相生成。PCT实验结果表明:B、Na、Ca元素的归一化浸出率随浸泡时间的增加而降低,并在28d后保持不变,分别为8.4、7.8、2.2mg/(m~2·d),与硼硅酸盐玻璃固化体浸出率处于同一数量级。
Glass-ceramics belonging to SiO_2-Na_2O-B_2O_3-BaO-CaO-ZrO_2-TiO_2 system were prepared by a melting-heat treatment method.The differential thermal analysis(DTA),Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD)and scanning electron microscope(SEM)were used to research the effects of the CaO content(CaO,TiO_2 and ZrO_2 mole ratio is x∶2∶1,x=0.5-6)on crystalline phases and microstructure of samples when the concentration of nucleating agents(CaO,TiO_2 and ZrO_2)is 45%.The leaching resistance of zirconolite-barium borosilicate glass-ceramicsof C-2(x=2)was characterized by product consistency test(PCT).The results show that the glass network structure is mainly formed of[SiO_4],[BO_3]and [BO_4],the increase of calcium concentration leads to more B ions exist in the form of[BO_4]tetrahedral units in the glass network.The glass transition temperature Tggradually increases and the exothermic peak temperature gradually decreases while the strength of exothermic peak increases with the CaO content.The other crystalline phase(ie.TiO_2 and ZrO_2)forms in addition to CaZrTi_2O_7 phase with x<2 while only CaZrTi_2O_7 phase forms with x=2and 4.The stellate CaZrTi_2O_7 and columnar CaTiO_3 phases are observed for the sample with x=6.The PCT experiment of glass-ceramics shows that the normalized leaching rates of B,Na and Ca gradually decrease with increasing leaching time and remain almost unchanged after 28 d,about 8.4,7.8,2.2mg/(m~2·d),respectively,which are the same order of magnitude of borosilicate glass waste.
Glass-ceramics belonging to SiO_2-Na_2O-B_2O_3-BaO-CaO-ZrO_2-TiO_2 system were prepared by a melting-heat treatment method.The differential thermal analysis(DTA),Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD)and scanning electron microscope(SEM)were used to research the effects of the CaO content(CaO,TiO_2 and ZrO_2 mole ratio is x∶2∶1,x=0.5-6)on crystalline phases and microstructure of samples when the concentration of nucleating agents(CaO,TiO_2 and ZrO_2)is 45%.The leaching resistance of zirconolite-barium borosilicate glass-ceramicsof C-2(x=2)was characterized by product consistency test(PCT).The results show that the glass network structure is mainly formed of[SiO_4],[BO_3]and [BO_4],the increase of calcium concentration leads to more B ions exist in the form of[BO_4]tetrahedral units in the glass network.The glass transition temperature Tggradually increases and the exothermic peak temperature gradually decreases while the strength of exothermic peak increases with the CaO content.The other crystalline phase(ie.TiO_2 and ZrO_2)forms in addition to CaZrTi_2O_7 phase with x<2 while only CaZrTi_2O_7 phase forms with x=2and 4.The stellate CaZrTi_2O_7 and columnar CaTiO_3 phases are observed for the sample with x=6.The PCT experiment of glass-ceramics shows that the normalized leaching rates of B,Na and Ca gradually decrease with increasing leaching time and remain almost unchanged after 28 d,about 8.4,7.8,2.2mg/(m~2·d),respectively,which are the same order of magnitude of borosilicate glass waste.
引文
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[15]LOISEAU P,CAURANT D,MAJERUS N,et al.Crystallization study of(TiO2,ZrO2)-rich SiO2-Al2O3-CaO glasses,PartⅡ:Surface and internal crystallization processes investigated by differential thermal analysis(DTA)[J].Journal of Materials Science,2003,38(4):853-864.
[16]陈珍霞,全健,钟韵鸣.Al2O3对低熔点硼硅酸盐玻璃结构和性能的影响[J].武汉理工大学学报,2009,31(22):26-29.CHEN Zhenxia,QUAN Jian,ZHONG Yunming.Effect of Al2O3on structure and the thermal propertities of low-melting borosilicate glass[J].Journal of Wuhan University of Technology,2009,31(22):26-29(in Chinese).
[17]万金鹏,程金树,陆平.n(B2O3)/n(SiO2)对硼硅酸盐玻璃结构和性能的影响[J].玻璃与搪瓷,2007,35(3):15-20.WAN Jinpeng,CHENG Jinshu,LU Ping.Influence of n(B2O3)/n(SiO2)on the structure and properties of borosilicate glass[J].Glass&Enamel,2007,35(3):15-20(in Chinese).
[18]WACLAWSKA I.Glass transition effect of amorphous borates[J].Thermochimica Acta,1995,269/270(1):457-464.
[19]TANG Yongxing,JIANG Zhonghong,SONG Xiuyu.NMR,IR and Raman spectra study of the structure of borate and borosilicate glasses[J].Journal of Non-Crystalline Solids,1989,112(1-3):131-135.
[20]MAHMOUDYSEPEHR M,MARGHUSSIAN V K.SiO2-PbO-CaO-ZrO2-TiO2-(B2O3-K2O),a new zirconolite glass-ceramic system:Crystallization behavior and microstructure evaluation[J].Journal of the American Ceramic Society,2009,92(7):1 540-1 546.
[21]LOISEAU P,CAURANT D,MAJERUS N,et al.Crystallization study of(TiO2,ZrO2)-rich SiO2-Al2O3-CaO glasses[J].Journal of Materials Science,2003,38(4):843-852.
[22]CRAWFORD C L,MARRA J C,BIBLER N E.Glass fabrication and product consistency testing of lanthanide borosilicate glass for plutonium disposition[J].Journal of Alloys and Compounds,2007,444-445(1):569-579.
[23]MARTIN C,RIBET I,FRUGIER P,et al.Alteration kinetics of the glass-ceramic zirconolite and role of the alteration film:Comparison with the SON68glass[J].Journal of Nuclear Materials,2007,366(1-2):277-287.
[2]CAURANTA D,MAJERUS N,LOISEAU P,et al.Crystallization of neodymium-rich phases in silicate glasses developed for nuclear waste immobilization[J].Journal of Nuclear Materials,2006,354(1-3):143-162.
[3]MANARA D,GRANDJEAN A,PINET O,et al.Sulfur behavior in silicate glasses and melts:Implications for sulfate incorporation in nuclear waste glasses as a function of alkali cation and V2O5 content[J].Journal of Non-Crystalline Solids,2007,353(1):12-23.
[4]刘丽君,郄东生,周慧,等.高硫高钠高放废液玻璃固化的配方验证[J].核化学与放射化学,2014,36(3):163-168.LIU Lijun,QIE Dongsheng,ZHOU Hui,et al.Verification experiment research of glass formulation for high sodium and high sulfur bearing HLLW[J].Journal of Nuclear and Radiochemistry,2014,36(3):163-168(in Chinese).
[5]罗上庚,杨建文,朱鑫璋,等.人造岩石固化包容锕系核素废物[J].化学学报,2000,58(12):1 608-1 614.LUO Shanggeng,YANG Jianwen,ZHU Xinzhang,et al.Synroc solidification of actinide wastes[J].Acta Chimica Sinica,2000,58(12):1 608-1 614(in Chinese).
[6]吴浪,徐东,李玉香,等.掺钕钙钛锆石基玻璃陶瓷制备及浸出性能研究[J].原子能科学技术,2014,48(11):1 943-1 948.WU Lang,XU Dong,LI Yuxiang,et al.Preparation and leaching property of Nd-doped zirconolite-based glass-ceramic[J].Atomic Energy Science and Technology,2014,48(11):1 943-1 948(in Chinese).
[7]李鹏,丁新更,杨辉,等.钙钛锆石玻璃陶瓷体的晶化和抗浸出性能[J].硅酸盐学报,2012,40(2):324-328.LI Peng,DING Xingeng,YANG Hui,et al.Crystallization and leaching resistance performance of zirconolite-based glass-ceramics[J].Journal of the Chinese Ceramic Society,2012,40(2):324-328(in Chinese).
[8]ADVOCAT T,FILLET C,MARILLET J.Nddoped zirconolite ceramic and glass-ceramics by meilting and controlled cooling[J].Materials Research Society Symposium Proceeding,1997,506(1):55-62.
[9]LIN J S,SHEN P Y.Fabrication of CaO-ZrO2-TiO2-Al2O3-B2O3-SiO2 glasses and glass-ceramics[J].Journal of Non-Crystalline Solids,1996,204(2):135-140.
[10]LOISEAU P,CAURANT D,BAFFIR N,et al.Glass-ceramic nuclear waste forms obtained from SiO2-Al2O3-CaO-ZrO2-TiO2 glasses containing lanthanides(Ce,Nd,Eu,Gd,Yb)and actinides(Th):Study of internal crystallization[J].Journal of Nuclear Materials,2004,335(1):14-32.
[11]CAURANT D,LOISEAU P,BARDEZ I,et al.Effect of Al2O3 concentration on zirconolite(Ca(Zr,Hf)Ti2O7)crystallization in(TiO2,ZrO2,HfO2)-rich SiO2-Al2O3-CaO-Na2O glasses[J].Journal of Nuclear Materials,2007,42(20):8 558-8 570.
[12]张振涛,王雷,甘学英,等.玻璃-陶瓷固化工艺研究[R].北京:中国原子能科学研究院,2007.
[13]徐东,吴浪,李会东,等.钙钛锆石-钡硼硅酸盐玻璃陶瓷的制备及表征[J].硅酸盐学报,2015,43(1):127-132.XU Dong,WU Lang,LI Huidong,et al.Preparation and characterization of zirconolite-based barium borosilicate glass-ceramics[J].Journal of the Chinese Ceramic Society,2015,43(1):127-132(in Chinese).
[14]JANTZEN C M,BIBLER N E,BEAM D C,et al.C1285-14 Standard test methods for determining chemical durability of nuclear,hazardous,and mixed waste glasses andmultiphase glass ceramics:The product consistency test(PCT)[S].US:ASTM,2014.
[15]LOISEAU P,CAURANT D,MAJERUS N,et al.Crystallization study of(TiO2,ZrO2)-rich SiO2-Al2O3-CaO glasses,PartⅡ:Surface and internal crystallization processes investigated by differential thermal analysis(DTA)[J].Journal of Materials Science,2003,38(4):853-864.
[16]陈珍霞,全健,钟韵鸣.Al2O3对低熔点硼硅酸盐玻璃结构和性能的影响[J].武汉理工大学学报,2009,31(22):26-29.CHEN Zhenxia,QUAN Jian,ZHONG Yunming.Effect of Al2O3on structure and the thermal propertities of low-melting borosilicate glass[J].Journal of Wuhan University of Technology,2009,31(22):26-29(in Chinese).
[17]万金鹏,程金树,陆平.n(B2O3)/n(SiO2)对硼硅酸盐玻璃结构和性能的影响[J].玻璃与搪瓷,2007,35(3):15-20.WAN Jinpeng,CHENG Jinshu,LU Ping.Influence of n(B2O3)/n(SiO2)on the structure and properties of borosilicate glass[J].Glass&Enamel,2007,35(3):15-20(in Chinese).
[18]WACLAWSKA I.Glass transition effect of amorphous borates[J].Thermochimica Acta,1995,269/270(1):457-464.
[19]TANG Yongxing,JIANG Zhonghong,SONG Xiuyu.NMR,IR and Raman spectra study of the structure of borate and borosilicate glasses[J].Journal of Non-Crystalline Solids,1989,112(1-3):131-135.
[20]MAHMOUDYSEPEHR M,MARGHUSSIAN V K.SiO2-PbO-CaO-ZrO2-TiO2-(B2O3-K2O),a new zirconolite glass-ceramic system:Crystallization behavior and microstructure evaluation[J].Journal of the American Ceramic Society,2009,92(7):1 540-1 546.
[21]LOISEAU P,CAURANT D,MAJERUS N,et al.Crystallization study of(TiO2,ZrO2)-rich SiO2-Al2O3-CaO glasses[J].Journal of Materials Science,2003,38(4):843-852.
[22]CRAWFORD C L,MARRA J C,BIBLER N E.Glass fabrication and product consistency testing of lanthanide borosilicate glass for plutonium disposition[J].Journal of Alloys and Compounds,2007,444-445(1):569-579.
[23]MARTIN C,RIBET I,FRUGIER P,et al.Alteration kinetics of the glass-ceramic zirconolite and role of the alteration film:Comparison with the SON68glass[J].Journal of Nuclear Materials,2007,366(1-2):277-287.