稀土电解槽石墨内衬高温氧化过程中孔隙结构演化规律及其分形特征
|
摘要
针对稀土电解槽石墨内衬破损问题,采用显微CT研究稀土电解槽石墨内衬在不同氧化时间下内部微观孔隙结构演化特征,考察了孔隙率、孔喉尺寸、孔喉形状因子、孔隙分形维数等参数的变化规律。结果表明:石墨内衬氧化0、1h、2h、3h后的平均孔隙率在逐渐增大,分别为4.02%、8.53%、11.18%、13.35%,孔喉尺寸为5～25μm与孔喉形状因子为0.02～0.05的孔喉数量从17903增加到39388。进一步应用分形理论分析发现:氧化不同时间的石墨内衬孔隙构造均符合分形规律,且随着氧化时间的增大,石墨内衬的氧化腐蚀越来越严重,石墨内衬孔隙分形维数从1.5722增加到1.6985。因此可以间接地用分形维数来判断石墨内衬的氧化腐蚀程度。最后建立了石墨内衬渗透率的分形表达式,由此计算氧化0、1h、2h、3h的石墨内衬理论渗透率分别为0.10μm2、0.25μm2、0.37μm2、0.52μm2。计算结果与其实际渗透率0.09μm2、0.18μm2、0.38μm2、0.57μm2相差不大,可以用此式来预测石墨内衬的渗透率。
In view of the breakage of graphite lining in rare earth electrolytic cell, micro-CT was used to study the evolution characteristics of internal micro-pore structure of rare-earth electrolytic cell graphite lining under different oxidation time. The variation rules of the porosity, pore throat size, pore throat shape factor, pore fractal dimension and other parameters were investigated. The result showed that the average porosity of the graphite lining was gradually increased after 0, 1 h, 2 h and 3 h of oxidation time, and the porosity were 4.02%, 8.53%, 11.18%, and 13.35%, respectively. The number of pore throats with size between 5—25μm and shape factor between 0.02—0.05 increased from 17903 to 39388. Therefore,fractal dimension can be used indirectly to judge the degree of oxidation corrosion of graphite lining.Finally, a fractal expression of the permeability of the graphite liner was established. The theoretical permeability of the graphite liner under the oxidation time of 0, 1 h, 2 h, and 3 h was calculated to be0.10μm2, 0.25μm2, 0.37μm2, and 0.52μm2, respectively. The calculated result were similar to the actual permeability which were 0.09μm2, 0.18μm2, 0.38μm2 and 0.57μm2, therefore, it can be used to predict the permeability of graphite lining.
In view of the breakage of graphite lining in rare earth electrolytic cell, micro-CT was used to study the evolution characteristics of internal micro-pore structure of rare-earth electrolytic cell graphite lining under different oxidation time. The variation rules of the porosity, pore throat size, pore throat shape factor, pore fractal dimension and other parameters were investigated. The result showed that the average porosity of the graphite lining was gradually increased after 0, 1 h, 2 h and 3 h of oxidation time, and the porosity were 4.02%, 8.53%, 11.18%, and 13.35%, respectively. The number of pore throats with size between 5—25μm and shape factor between 0.02—0.05 increased from 17903 to 39388. Therefore,fractal dimension can be used indirectly to judge the degree of oxidation corrosion of graphite lining.Finally, a fractal expression of the permeability of the graphite liner was established. The theoretical permeability of the graphite liner under the oxidation time of 0, 1 h, 2 h, and 3 h was calculated to be0.10μm2, 0.25μm2, 0.37μm2, and 0.52μm2, respectively. The calculated result were similar to the actual permeability which were 0.09μm2, 0.18μm2, 0.38μm2 and 0.57μm2, therefore, it can be used to predict the permeability of graphite lining.
引文
[1]刘思德.世界稀土资源供给状况[J].稀土信息,2018(1):28-30.LIU Side.The situation of the supply of rare earth resources in the world[J].Rare Earth Information,2018(1):28-30.
[2]LUO Xiaowei,ROBIN Jean-charles,YU Suyuan.Effect of temperature on graphite oxidation behavior[J].Nuclear Engineering and Design,2004,227:273-280.
[3]石富.稀土电解槽的研究现状及发展趋势[J].中国稀土学报,2007,25(s1):70-76.SHI Fu.Research status and development trend of rare earth electrolyzer[J].Chinese Journal of Rare Earths,2007,25(s1):70-76.
[4]杨斌清,邓宇民,杨安.提高稀土金属电解炉使用寿命的研究及生产实践[J].江西冶金,2001,21(3/4):63-65.YANG Binqing,DENG Yumin,YANG An.Research and production practice of improving service life of rare earth metal electrolytic furnace[J].Jiangxi Metallurgy,2001,21(3/4):63-65.
[5]任永红,陈国华,张志军,等.氟氧化钕耐火材料的研制与应用[J].耐火材料,2003,3:147-149.REN Yonghong,CHEN Guohua,ZHANG Zhijun,et al.Preparation and application of neodymium oxide refractory[J].Refractory Material,2003,3:147-149.
[6]张小联,邓左民,王俊,等.稀土金属块状多阳极连续电解[J].江西有色金属,2003,3:28-30.ZHANG Xiaolian,DENG Zuomin,WANG Jun,et al.Continuous electrolysis of RE metals with block like multianodes[J].Jiangxi Nonferrous Metals,2003,3:28-30.
[7]李想,薛济来,郎光辉,等.铝用石墨质阴极不同焙烧温度下孔隙结构演化[J].北京科技大学学报,2014,36(9):1233-1240.LI Xiang,XUE Jilai,LANG Guanghui,et al.Pore structure evolution of graphite cathode for aluminum under different calcination temperatures[J].Journal of University of Science and Technology Beijing,2014,36(9):1233-1240.
[8]刘中兴,徐子娟,王伟,等.稀土电解槽石墨阳极的研究[J].有色金属(冶炼部分),2014,1:45-49.LIU Zhongxing,XU Zijuan,WANG Wei,et al.Study on graphite anode of rare earth electrolytic cell[J].Nonferrous Metals(Smelting Parts),2014,1:45-49.
[9]STEEL K S,DAWSON R E,JENKINS R J,et al.Use of rheometry and micro-CT analysis to understand pore structure development[J].Fuel Processing Technology,2017,155:106-113.
[10]SUN Wei,HOU Kepeng,YANG Zhiquan,et al.X-ray CT threedimensional reconstruction and discrete element analysis of the cement paste backfill pore structure under uniaxial compression[J].Construction and Building Materials,2017,138:69-78.
[11]AI Li,ZHAO Jiafei,WANG Jiaqi,et al.Analyzing permeability of the irregular porous media containing methane hydrate using pore network model combined with CT[J].Energy Procedia,2017,105:4802-4807.
[12]AKIRA S,YUZO O.Analysis of pore structure and water permeation property of a shale rock by means of X-Ray CT[J].Procedia Engineering,2017,191:666-673.
[13]JONATHAN P M,QUENTIN P C,XU H,et al.A review of the application of X-ray computed tomography to the study of coal[J].Fuel,2017,209:10-24.
[14]王刚,沈俊男,褚翔宇,等.基于CT三维重建的高阶煤孔裂隙结构综合表征和分析[J].煤炭学报,2017,42(8):2074-2080.WANG Gang,SHEN Junnan,CHU Xiangyu,et al.Characterization and analysis of pores and fissures of high-rank coalbased on CT threedimensional reconstruction[J].Journal of China Coal Societ,2017,42(8):2074-2080.
[15]于豪,李劲松,晏信飞,等.非均质碳酸盐岩储层微观孔隙结构表征与气藏检测[J].石油物探,2017,56(4):472-482.YU Hao,LI Jinsong,YAN Xinfei,et al.Microscopic pore structure characterization of heterogeneous carbonate reservoirs and gasdetection:a case study from limestone gas reservoirs on the right bank block of Amu Darya River[J].Geophysical Prospecting for Petroleun,2017,56(4):472-482.
[16]刘庆生,段旭,李江霖,等.基于显微CT的石墨内衬的孔隙及其分形特征[J].材料科学与工艺,2018,26(4):59-65.LIU Qingsheng,DUAN Xu,LI Jianglin,et al.Pore and fractal characteristics of graphite lining based on micro CT[J].Material Science and Technology 2018,26(4):59-65.
[17]张天付,谢淑云,王鑫,等.孔隙型储层的孔隙系统三维量化表征--以四川、塔里木盆地白云岩为例[J].海相油气地质,2016,21(4):1-10.ZHANG Tianfu,XIE Shuyun,WANG Xin,et al.Three dimensional quantitative characterization of pore system in porous reservoirs--a case study of dolomite in Sichuan and Tarim Basin[J].Marine Origin Petroleum Geology,2016,21(4):1-10.
[18]刘俊亮,田长安,曾燕伟,等.分形多孔介质孔隙微结构参数与渗透率的分维关系[J].水科学进展,2006,6:812-817.LIU Junliang,TIAN Changan,ZENG Yanwei,et al.Fractal dimensionality dependence of microstructural parameters andpermeability in fractal porous media[J].Advances in Water Science,2006,6:812-817.
[2]LUO Xiaowei,ROBIN Jean-charles,YU Suyuan.Effect of temperature on graphite oxidation behavior[J].Nuclear Engineering and Design,2004,227:273-280.
[3]石富.稀土电解槽的研究现状及发展趋势[J].中国稀土学报,2007,25(s1):70-76.SHI Fu.Research status and development trend of rare earth electrolyzer[J].Chinese Journal of Rare Earths,2007,25(s1):70-76.
[4]杨斌清,邓宇民,杨安.提高稀土金属电解炉使用寿命的研究及生产实践[J].江西冶金,2001,21(3/4):63-65.YANG Binqing,DENG Yumin,YANG An.Research and production practice of improving service life of rare earth metal electrolytic furnace[J].Jiangxi Metallurgy,2001,21(3/4):63-65.
[5]任永红,陈国华,张志军,等.氟氧化钕耐火材料的研制与应用[J].耐火材料,2003,3:147-149.REN Yonghong,CHEN Guohua,ZHANG Zhijun,et al.Preparation and application of neodymium oxide refractory[J].Refractory Material,2003,3:147-149.
[6]张小联,邓左民,王俊,等.稀土金属块状多阳极连续电解[J].江西有色金属,2003,3:28-30.ZHANG Xiaolian,DENG Zuomin,WANG Jun,et al.Continuous electrolysis of RE metals with block like multianodes[J].Jiangxi Nonferrous Metals,2003,3:28-30.
[7]李想,薛济来,郎光辉,等.铝用石墨质阴极不同焙烧温度下孔隙结构演化[J].北京科技大学学报,2014,36(9):1233-1240.LI Xiang,XUE Jilai,LANG Guanghui,et al.Pore structure evolution of graphite cathode for aluminum under different calcination temperatures[J].Journal of University of Science and Technology Beijing,2014,36(9):1233-1240.
[8]刘中兴,徐子娟,王伟,等.稀土电解槽石墨阳极的研究[J].有色金属(冶炼部分),2014,1:45-49.LIU Zhongxing,XU Zijuan,WANG Wei,et al.Study on graphite anode of rare earth electrolytic cell[J].Nonferrous Metals(Smelting Parts),2014,1:45-49.
[9]STEEL K S,DAWSON R E,JENKINS R J,et al.Use of rheometry and micro-CT analysis to understand pore structure development[J].Fuel Processing Technology,2017,155:106-113.
[10]SUN Wei,HOU Kepeng,YANG Zhiquan,et al.X-ray CT threedimensional reconstruction and discrete element analysis of the cement paste backfill pore structure under uniaxial compression[J].Construction and Building Materials,2017,138:69-78.
[11]AI Li,ZHAO Jiafei,WANG Jiaqi,et al.Analyzing permeability of the irregular porous media containing methane hydrate using pore network model combined with CT[J].Energy Procedia,2017,105:4802-4807.
[12]AKIRA S,YUZO O.Analysis of pore structure and water permeation property of a shale rock by means of X-Ray CT[J].Procedia Engineering,2017,191:666-673.
[13]JONATHAN P M,QUENTIN P C,XU H,et al.A review of the application of X-ray computed tomography to the study of coal[J].Fuel,2017,209:10-24.
[14]王刚,沈俊男,褚翔宇,等.基于CT三维重建的高阶煤孔裂隙结构综合表征和分析[J].煤炭学报,2017,42(8):2074-2080.WANG Gang,SHEN Junnan,CHU Xiangyu,et al.Characterization and analysis of pores and fissures of high-rank coalbased on CT threedimensional reconstruction[J].Journal of China Coal Societ,2017,42(8):2074-2080.
[15]于豪,李劲松,晏信飞,等.非均质碳酸盐岩储层微观孔隙结构表征与气藏检测[J].石油物探,2017,56(4):472-482.YU Hao,LI Jinsong,YAN Xinfei,et al.Microscopic pore structure characterization of heterogeneous carbonate reservoirs and gasdetection:a case study from limestone gas reservoirs on the right bank block of Amu Darya River[J].Geophysical Prospecting for Petroleun,2017,56(4):472-482.
[16]刘庆生,段旭,李江霖,等.基于显微CT的石墨内衬的孔隙及其分形特征[J].材料科学与工艺,2018,26(4):59-65.LIU Qingsheng,DUAN Xu,LI Jianglin,et al.Pore and fractal characteristics of graphite lining based on micro CT[J].Material Science and Technology 2018,26(4):59-65.
[17]张天付,谢淑云,王鑫,等.孔隙型储层的孔隙系统三维量化表征--以四川、塔里木盆地白云岩为例[J].海相油气地质,2016,21(4):1-10.ZHANG Tianfu,XIE Shuyun,WANG Xin,et al.Three dimensional quantitative characterization of pore system in porous reservoirs--a case study of dolomite in Sichuan and Tarim Basin[J].Marine Origin Petroleum Geology,2016,21(4):1-10.
[18]刘俊亮,田长安,曾燕伟,等.分形多孔介质孔隙微结构参数与渗透率的分维关系[J].水科学进展,2006,6:812-817.LIU Junliang,TIAN Changan,ZENG Yanwei,et al.Fractal dimensionality dependence of microstructural parameters andpermeability in fractal porous media[J].Advances in Water Science,2006,6:812-817.