煤的电化学脱水过程及电解槽模拟优化研究
摘要
细粒煤水分的增加,在炼焦过程中,会增加热能消耗,延长焦化时间,降低焦炉产率,缩短炼焦炉使用寿命；对于动力用煤,其发热量随水分增高而下降；运输时,煤会随着水分渗出而流失,既浪费了煤炭资源,又污染了环境。另外,细粒煤水分偏高,还会导致其堆放场地周围煤泥水积聚,造成煤炭资源的浪费和环境污染,因此细粒煤水分对后续加工有非常重要的影响。目前针对细粒煤的脱水设计还处于探索阶段,脱水设备的研制缺乏实用的理论依据,通过模拟来优化脱水设备结构进而完善脱水理论的研究。研究证明细粒煤带有负电荷,可以通过电解作用,改变细粒煤的一系列性能,来降低细粒煤水分。
本文以西曲煤(-0.5mm)为研究对象,在研究西曲煤的基本性质的基础上,考察了加入电解质电解的电化学处理,研究细粒煤的电化学脱水中,电极材料、煤浆浓度、电解电流、电解时间、电解质用量、不同粒级以及内水对脱水效果的影响,并得出最佳的工艺条件。在此基础上利用ANSYS和FLUENT软件,进行电解槽电场的模拟及流场的模拟,并对实验进行验证,为适合细粒煤电化学脱水的设计提供了理论依据,实验分析结果如下：
1.考察了石墨-铁、铝-铝、铁-铁、铜-铜不同电极对细粒煤脱水效果的影响,得出用石墨作阳极、铁作阴极不但过滤速度快、而且滤饼水分低,滤饼水分降低了3%,消耗电解质的量也最低,电解质硫酸铝的量为500g/t。
2.通过不同电解质对细粒煤电化学脱水效果影响研究,可以看出电解质为铝盐时,脱水效果最好。在以硫酸铝为电解质电解的情况下,得出最佳工艺条件：电解时间为30min；电流为0.3A；矿浆浓度25%时；电解质用量为500g/t,滤饼水分降低了4%。
3.考察不同粒级煤电化学内水脱除效果,得出只加电解质,对粒级0.125-0.25mm适宜,滤饼水分约20%；只电解,粒级-0.125-0.5mm效果明显,滤饼水分为21%；加电解质、电解,粒级-0.25-0.5mm较其它粒级滤饼水分降低了8%。
4.利用Ansys软件对电解槽电场模拟,得出六边形八面体相邻阴阳极的电解槽结构有利于细粒煤的充分电解,对细粒煤煤浆与电解质的混合液电场的分布面积是最广的,能够充分对大部分,甚至全部分布在其中的细粒煤进行电解,并且占地少,而且也便于控制。
5.通过Fluent软件对电解槽流场模拟,可知转子半径为1.4cm,转速为78.54rad／s更有利于电解。
The upper moisture will result in increase in the expense of heat energy, prolonging the time of coking, reducing the efficiency of cookery, and shortening the use time of cookery for coking. For power coal, the calorific value of coal decreases as the moisture in coal increases. Coal in the transport, it will be lost as the water leakage not only wastes the coal resources, but also pollutes the environment. In addition, the high moisture in fine coal, also leads to the accumulation of slime water piled around the venue, resulting in a waste of coal resources and environmental pollution. Therefore, the follow-up processing of fine coal dewatering has a very significant impact. At present, the study for a fine piece of coal dehydration design is still in exploration phase, and the research of dewatering equipment is lack of practical theory, with impersonated to optimize the structure of dehydration device and improve the theoretical study. The study has proved that the surface of fine coal is negative, so it is viable to change a series of capability of fine coal, insuring the dehydration of fine coal, by electrolysis.
This paper chooses Xiqu coal (-0.5mm) for the study, on the base of investigation of the essential properties of Xiqu coal, investigated by adding electrolyte electrochemical electrolysis treatment, and studies the effect of electrode materials, coal slurry concentration, the electrolytic current, electrolysis time, the amount of electrolyte, various size and inland water in the dehydration and may obtain the optimal conditions. On this basis, using ANSYS and FLUENT software for electric field simulation and flow field simulation, and carries through experimental verification, as appropriate to the design of dewatering of fine coal chemistry provides a theoretical basis, the experimental results are as follows:
1. The effects of graphite-iron, aluminum-aluminum, iron-iron, copper-copper electrodes on the fine coal dewatering is investigated. The research has shown that using graphite as the anode, iron as the cathode, not only the filtration rate is fast,but also the moisture in filter cake is low, cake moisture reduces 3%, and the amount of electrolyte depletion is lowest, electrolyte content of 500g/t.
2. The effects of different electrolytes on the dewatering of fine coal is investigated, and obtained while the electrolyte was the aluminum salt, the dehydration was the best, in the case of adding aluminum electrolyte, the optimal, condition is got:electrolysis time is 30min; current strength is 0.3A; pulp concentration is 25%; electrolyte level is 500g/t, cake moisture reduces 4%.
3. Different fractions of Xiqu coal dewatering electrochemical experiments were investigated, the result shows that in the case of adding electrolyte,it is advantageous for grain size 0.125-0.25mm to remove internal water; only being electrolyzed is favorable for grain size-0.125-0.5mm to remove internal water, and the cake moisture is 21%; with adding electrolyte, being electrolyzed, the cake moisture of grain size-0.25-0.5mm is reduced 8% than others.
4. Utilizing the Ansys to simulate the electric field, it is obtained that hexagonal octahedral adjacent anode and cathode of the electrolytic cell structure is beneficial to electrolyze fine coal, coal slurry of fine coal by electric field with a mixture of electrolytes distribution area is the most extensive, most fully on, or even all located in one of the fine coal electrolysis, and footprint is small, further more it is easy to control.
5. Utilizing the Fluent to simulate the flow field, it is obtained that rotor radius of 1.4cm, speed 78.54rad/s is more conducive to electrolysis.
本文以西曲煤(-0.5mm)为研究对象,在研究西曲煤的基本性质的基础上,考察了加入电解质电解的电化学处理,研究细粒煤的电化学脱水中,电极材料、煤浆浓度、电解电流、电解时间、电解质用量、不同粒级以及内水对脱水效果的影响,并得出最佳的工艺条件。在此基础上利用ANSYS和FLUENT软件,进行电解槽电场的模拟及流场的模拟,并对实验进行验证,为适合细粒煤电化学脱水的设计提供了理论依据,实验分析结果如下：
1.考察了石墨-铁、铝-铝、铁-铁、铜-铜不同电极对细粒煤脱水效果的影响,得出用石墨作阳极、铁作阴极不但过滤速度快、而且滤饼水分低,滤饼水分降低了3%,消耗电解质的量也最低,电解质硫酸铝的量为500g/t。
2.通过不同电解质对细粒煤电化学脱水效果影响研究,可以看出电解质为铝盐时,脱水效果最好。在以硫酸铝为电解质电解的情况下,得出最佳工艺条件：电解时间为30min；电流为0.3A；矿浆浓度25%时；电解质用量为500g/t,滤饼水分降低了4%。
3.考察不同粒级煤电化学内水脱除效果,得出只加电解质,对粒级0.125-0.25mm适宜,滤饼水分约20%；只电解,粒级-0.125-0.5mm效果明显,滤饼水分为21%；加电解质、电解,粒级-0.25-0.5mm较其它粒级滤饼水分降低了8%。
4.利用Ansys软件对电解槽电场模拟,得出六边形八面体相邻阴阳极的电解槽结构有利于细粒煤的充分电解,对细粒煤煤浆与电解质的混合液电场的分布面积是最广的,能够充分对大部分,甚至全部分布在其中的细粒煤进行电解,并且占地少,而且也便于控制。
5.通过Fluent软件对电解槽流场模拟,可知转子半径为1.4cm,转速为78.54rad／s更有利于电解。
The upper moisture will result in increase in the expense of heat energy, prolonging the time of coking, reducing the efficiency of cookery, and shortening the use time of cookery for coking. For power coal, the calorific value of coal decreases as the moisture in coal increases. Coal in the transport, it will be lost as the water leakage not only wastes the coal resources, but also pollutes the environment. In addition, the high moisture in fine coal, also leads to the accumulation of slime water piled around the venue, resulting in a waste of coal resources and environmental pollution. Therefore, the follow-up processing of fine coal dewatering has a very significant impact. At present, the study for a fine piece of coal dehydration design is still in exploration phase, and the research of dewatering equipment is lack of practical theory, with impersonated to optimize the structure of dehydration device and improve the theoretical study. The study has proved that the surface of fine coal is negative, so it is viable to change a series of capability of fine coal, insuring the dehydration of fine coal, by electrolysis.
This paper chooses Xiqu coal (-0.5mm) for the study, on the base of investigation of the essential properties of Xiqu coal, investigated by adding electrolyte electrochemical electrolysis treatment, and studies the effect of electrode materials, coal slurry concentration, the electrolytic current, electrolysis time, the amount of electrolyte, various size and inland water in the dehydration and may obtain the optimal conditions. On this basis, using ANSYS and FLUENT software for electric field simulation and flow field simulation, and carries through experimental verification, as appropriate to the design of dewatering of fine coal chemistry provides a theoretical basis, the experimental results are as follows:
1. The effects of graphite-iron, aluminum-aluminum, iron-iron, copper-copper electrodes on the fine coal dewatering is investigated. The research has shown that using graphite as the anode, iron as the cathode, not only the filtration rate is fast,but also the moisture in filter cake is low, cake moisture reduces 3%, and the amount of electrolyte depletion is lowest, electrolyte content of 500g/t.
2. The effects of different electrolytes on the dewatering of fine coal is investigated, and obtained while the electrolyte was the aluminum salt, the dehydration was the best, in the case of adding aluminum electrolyte, the optimal, condition is got:electrolysis time is 30min; current strength is 0.3A; pulp concentration is 25%; electrolyte level is 500g/t, cake moisture reduces 4%.
3. Different fractions of Xiqu coal dewatering electrochemical experiments were investigated, the result shows that in the case of adding electrolyte,it is advantageous for grain size 0.125-0.25mm to remove internal water; only being electrolyzed is favorable for grain size-0.125-0.5mm to remove internal water, and the cake moisture is 21%; with adding electrolyte, being electrolyzed, the cake moisture of grain size-0.25-0.5mm is reduced 8% than others.
4. Utilizing the Ansys to simulate the electric field, it is obtained that hexagonal octahedral adjacent anode and cathode of the electrolytic cell structure is beneficial to electrolyze fine coal, coal slurry of fine coal by electric field with a mixture of electrolytes distribution area is the most extensive, most fully on, or even all located in one of the fine coal electrolysis, and footprint is small, further more it is easy to control.
5. Utilizing the Fluent to simulate the flow field, it is obtained that rotor radius of 1.4cm, speed 78.54rad/s is more conducive to electrolysis.
引文
[1]邓金迪,沈丽娟,杨泽坤等.细粒煤脱水技术与设备现状及发展方向[J].矿山机械,2006,34(4)：77-80.
[2]谢广元.选矿学[M].北京：中国矿业大学出版社,2001：20-50.
[3]杨俊利,邢玉梅.我国细粒煤脱水技术与设备研究现状[J].过滤与分离,1999,(2)：37-34.
[4]孙路长,张书延.生物污泥的电渗透脱水[J].中国给水排水,2004,(5)：32-34.
[5]董宪姝,王瑞卿,姚素玲等.浮选精煤电解-过滤脱水效果初探[J].选煤技术,2009,(4)：12-14.
[6]武本成,朱建华等.辽河超稠油电化学脱水实验研究[J].石油化工高等学校学报.2004,17(1)：46-51.
[7]邵武、何绪文.加压-电化学脱水机的试验研究[J].河北煤炭,1995,(2)：23-25.
[8]Krishna R.Reddy, Adam Urbanek, Amid P.Khodadoust. Electroosmotic dewatering of dredged sediments:Bench-scale Investigation [J]. Journal of Environmental Management,2006, (78):200-208.
[9]J.Q.Shang, K.Y.Lo. Electrokinetic dewatering of phosphate clay [J]. Journal of Hazardous Materials,1997, (55):117-133.
[10]S.Gopalakrishnan, A.S.Mujumdar, M.E. Weber. Optimal off-time in interrupted electro osmotic dewatering [J]. Separations Technology,1996, (6):197-200.
[11]O.Laruea, R.J.Wakemanb, E.S.Tarletonb, E.Vorobieva. Pressure electro osmotic dewatering with continuous removal of electrolysis products [J]. Chemical Engineering Science,2006, (61):4732-4740.
[12]金卫华,刘铮,丁富新.电脱水技术应用于发酵产品固液分离的基础及特性[J].过程工程学报,2002,3(2)：23-26.
[13]孙锐.电渗透脱水在豆制品加工中的应用研究[D].北京：中国农业大学,2003.
[14]S.AL-ASHEH, R.JUMAH,F.BANAT and K.AL-ZOU. Direct current electro osmosis dewatering of tomato paste suspension food and byproducts processing [J].1982, (C3): 193-200.
[15]王淀佐,邱冠周,胡岳华.资源加工学[M].2005.
[16]Sarald Anlauf.选矿工业中超细粒悬浮液固液分离工艺的发展趋势和新理论[C].第十七届国际选矿会议文集,1991,(3)：219-231.
[17]单忠健,郭余庆.电化学脱水工艺的研究[J].中国矿业学报,1983,(1)：1-14.
[18]S.Gopalakrishnan, A.S. Mujumdar, M.E. Weber. Optimal off-time in interrupted electro osmotic dewatering[J]. Separations Technology,1996, (6):197-200.
[19]Rabie, H.R.Mujumdar, A.S.and Weber. M.E.Sepration.Technology [J]:1994,38(4).
[20]Yoshida, H.Practical. aspects of dewatering enhanced by electro osmosis[J]. Drying Technology,1993,11(4):787-814.
[21]Kobayashi, K.Hakoda, M.Yosoda, Y.Iwata. Electroosmotic flow through particle beds and electro osmotic pressure distribution[J]. Journal of Chemical Engineering of Japan, 1979,12(6):492-496.
[22]吉田裕志.电气渗透脱水过程电极脱水食料接触电阻抗[C].小山工业高等专门学校研究纪要,1999,(31)：147-154.
[23]Iwata, M.Igami, H.and Murase. Analysis of electro osmotic dewatering[J]. Journal of Chemical Engineering of Japan,1991,24(1):45-50.
[24]Walten J.Weber JR. Physico-chemical Processes for Water Quality Control[J]. Wiley-Interscience A Division of John Wiley and Sons, Inc,1972.
[25]单忠健.电化学脱水试验及研究[J].中国学术期刊电子出版社,1998.
[26]李修渠.食品物料的电特性及其应用研究[D].北京：中国农业大学,1999.
[27]胡筱敏.化学助滤剂[M].北京：冶金工业出版社,1999：118-128.
[28]董宪姝,任伟鹏等.选煤工业中常见助滤剂种类及其应用[J].中国煤炭,2009,35(4)：94-97.
[29]夏畅斌.表面活性剂对细粒和超细粒煤脱水的研究[J].煤炭科学技术,2000,29(3)：41-42.
[30]姚文锐,崔平等.表面活性剂作用下的微波加热对细粉煤脱水的影响[J].矿业安全与环保,2000,29(2)：8-10.
[31]于跃芹.电解质对氢氧化铝镁正电溶胶的聚沉作用[J].山东轻工业学院学报,2000,(12)：49-51.
[32]侯万国.pH和电解质对氢氧化铝镁溶胶稳定性的影响应用[J].1996,(4)：33-36.
[33]刘德群.胶体粒子的结构与胶体的聚沉[M].化学教学参考,2003.
[34]刘涛.精通ANSYS[M].北京：清华大学出版社,2001.
[35]余伟炜,高炳军.ANSYS在机械与化工装备中的应用[M].北京：中国水利水电出版社,2006.
[36]李志刚,邵长金等.大学物理实验中有限元软件ANSYS求解电场问题的应用[J].长春师范学院学报,2004,(12)：33-36.
[37]喻海良,崔青玲等.300kA铝电解槽三维电热场电位ANSYS分析[J].有色矿冶,2004,(6)：30-32.
[38]田杰,李林.基于ANSYS的电磁轴承支承刚度优化[J].机械制造与研究,2009,38(6)：17-18,32.
[39]陈兴润,张志峰.电磁搅拌法制备半固态浆料过程中电磁场的数值模拟[J].特种铸造及有色合金,2009,29(12)：1109-1111.
[40]周乃君,崔大光,周正明等.Fluent应用及研究[M].长沙：中南大学能源与动力工程学院,2007.
[41]江帆,黄鹏.Fluent高级应用与实例分析[M].北京：清华大学出版社,2008.
[42]王瑞金,张凯,王刚.Fluent技术基础与应用实例[M].北京：清华大学出版社,2007.
[43]王福军.计算流体动力学分析[M].北京：清华大学出版社,2004.
[44]侯权,潘红良等.基于Fluent的搅拌反应罐流场的优化研究[J].机械设计与研究,2005,21(3)：78-82.
[45]余江洪等.Fluent软件的多重网格并行算法及其性能[J].武汉理工大学学报,2009,33(1)：133-136.
[46]马艺等.Fluent软件在液-液旋流器中的应用[J].过滤与分离,2008.
[47]徐元力等.Fluent软件在圆柱绕流模拟中的应用[J].水利电力机械,2005,21(1)：39-41.
[48]天津大学物理化学教研室.物理化学[M].天津：高等教育出版社,2001.
[49]关振铎.无机材料物理性能[M].北京：清华大学出版社,1998.
[50]邱竹贤.铝电解[M].北京：冶金工业出版社,1995：4-5.
[51]M.Dolezil.国外金属矿选矿[J],1988,(6)：16-17.
[52]高廷耀,顾国维.水污染控制工程[M].北京：高等教育出版社,2001.
[53]邹立壮.不同水煤浆分散剂与煤之间的相互作用规律研究[J].北京：中国矿业大学,2003.
[2]谢广元.选矿学[M].北京：中国矿业大学出版社,2001：20-50.
[3]杨俊利,邢玉梅.我国细粒煤脱水技术与设备研究现状[J].过滤与分离,1999,(2)：37-34.
[4]孙路长,张书延.生物污泥的电渗透脱水[J].中国给水排水,2004,(5)：32-34.
[5]董宪姝,王瑞卿,姚素玲等.浮选精煤电解-过滤脱水效果初探[J].选煤技术,2009,(4)：12-14.
[6]武本成,朱建华等.辽河超稠油电化学脱水实验研究[J].石油化工高等学校学报.2004,17(1)：46-51.
[7]邵武、何绪文.加压-电化学脱水机的试验研究[J].河北煤炭,1995,(2)：23-25.
[8]Krishna R.Reddy, Adam Urbanek, Amid P.Khodadoust. Electroosmotic dewatering of dredged sediments:Bench-scale Investigation [J]. Journal of Environmental Management,2006, (78):200-208.
[9]J.Q.Shang, K.Y.Lo. Electrokinetic dewatering of phosphate clay [J]. Journal of Hazardous Materials,1997, (55):117-133.
[10]S.Gopalakrishnan, A.S.Mujumdar, M.E. Weber. Optimal off-time in interrupted electro osmotic dewatering [J]. Separations Technology,1996, (6):197-200.
[11]O.Laruea, R.J.Wakemanb, E.S.Tarletonb, E.Vorobieva. Pressure electro osmotic dewatering with continuous removal of electrolysis products [J]. Chemical Engineering Science,2006, (61):4732-4740.
[12]金卫华,刘铮,丁富新.电脱水技术应用于发酵产品固液分离的基础及特性[J].过程工程学报,2002,3(2)：23-26.
[13]孙锐.电渗透脱水在豆制品加工中的应用研究[D].北京：中国农业大学,2003.
[14]S.AL-ASHEH, R.JUMAH,F.BANAT and K.AL-ZOU. Direct current electro osmosis dewatering of tomato paste suspension food and byproducts processing [J].1982, (C3): 193-200.
[15]王淀佐,邱冠周,胡岳华.资源加工学[M].2005.
[16]Sarald Anlauf.选矿工业中超细粒悬浮液固液分离工艺的发展趋势和新理论[C].第十七届国际选矿会议文集,1991,(3)：219-231.
[17]单忠健,郭余庆.电化学脱水工艺的研究[J].中国矿业学报,1983,(1)：1-14.
[18]S.Gopalakrishnan, A.S. Mujumdar, M.E. Weber. Optimal off-time in interrupted electro osmotic dewatering[J]. Separations Technology,1996, (6):197-200.
[19]Rabie, H.R.Mujumdar, A.S.and Weber. M.E.Sepration.Technology [J]:1994,38(4).
[20]Yoshida, H.Practical. aspects of dewatering enhanced by electro osmosis[J]. Drying Technology,1993,11(4):787-814.
[21]Kobayashi, K.Hakoda, M.Yosoda, Y.Iwata. Electroosmotic flow through particle beds and electro osmotic pressure distribution[J]. Journal of Chemical Engineering of Japan, 1979,12(6):492-496.
[22]吉田裕志.电气渗透脱水过程电极脱水食料接触电阻抗[C].小山工业高等专门学校研究纪要,1999,(31)：147-154.
[23]Iwata, M.Igami, H.and Murase. Analysis of electro osmotic dewatering[J]. Journal of Chemical Engineering of Japan,1991,24(1):45-50.
[24]Walten J.Weber JR. Physico-chemical Processes for Water Quality Control[J]. Wiley-Interscience A Division of John Wiley and Sons, Inc,1972.
[25]单忠健.电化学脱水试验及研究[J].中国学术期刊电子出版社,1998.
[26]李修渠.食品物料的电特性及其应用研究[D].北京：中国农业大学,1999.
[27]胡筱敏.化学助滤剂[M].北京：冶金工业出版社,1999：118-128.
[28]董宪姝,任伟鹏等.选煤工业中常见助滤剂种类及其应用[J].中国煤炭,2009,35(4)：94-97.
[29]夏畅斌.表面活性剂对细粒和超细粒煤脱水的研究[J].煤炭科学技术,2000,29(3)：41-42.
[30]姚文锐,崔平等.表面活性剂作用下的微波加热对细粉煤脱水的影响[J].矿业安全与环保,2000,29(2)：8-10.
[31]于跃芹.电解质对氢氧化铝镁正电溶胶的聚沉作用[J].山东轻工业学院学报,2000,(12)：49-51.
[32]侯万国.pH和电解质对氢氧化铝镁溶胶稳定性的影响应用[J].1996,(4)：33-36.
[33]刘德群.胶体粒子的结构与胶体的聚沉[M].化学教学参考,2003.
[34]刘涛.精通ANSYS[M].北京：清华大学出版社,2001.
[35]余伟炜,高炳军.ANSYS在机械与化工装备中的应用[M].北京：中国水利水电出版社,2006.
[36]李志刚,邵长金等.大学物理实验中有限元软件ANSYS求解电场问题的应用[J].长春师范学院学报,2004,(12)：33-36.
[37]喻海良,崔青玲等.300kA铝电解槽三维电热场电位ANSYS分析[J].有色矿冶,2004,(6)：30-32.
[38]田杰,李林.基于ANSYS的电磁轴承支承刚度优化[J].机械制造与研究,2009,38(6)：17-18,32.
[39]陈兴润,张志峰.电磁搅拌法制备半固态浆料过程中电磁场的数值模拟[J].特种铸造及有色合金,2009,29(12)：1109-1111.
[40]周乃君,崔大光,周正明等.Fluent应用及研究[M].长沙：中南大学能源与动力工程学院,2007.
[41]江帆,黄鹏.Fluent高级应用与实例分析[M].北京：清华大学出版社,2008.
[42]王瑞金,张凯,王刚.Fluent技术基础与应用实例[M].北京：清华大学出版社,2007.
[43]王福军.计算流体动力学分析[M].北京：清华大学出版社,2004.
[44]侯权,潘红良等.基于Fluent的搅拌反应罐流场的优化研究[J].机械设计与研究,2005,21(3)：78-82.
[45]余江洪等.Fluent软件的多重网格并行算法及其性能[J].武汉理工大学学报,2009,33(1)：133-136.
[46]马艺等.Fluent软件在液-液旋流器中的应用[J].过滤与分离,2008.
[47]徐元力等.Fluent软件在圆柱绕流模拟中的应用[J].水利电力机械,2005,21(1)：39-41.
[48]天津大学物理化学教研室.物理化学[M].天津：高等教育出版社,2001.
[49]关振铎.无机材料物理性能[M].北京：清华大学出版社,1998.
[50]邱竹贤.铝电解[M].北京：冶金工业出版社,1995：4-5.
[51]M.Dolezil.国外金属矿选矿[J],1988,(6)：16-17.
[52]高廷耀,顾国维.水污染控制工程[M].北京：高等教育出版社,2001.
[53]邹立壮.不同水煤浆分散剂与煤之间的相互作用规律研究[J].北京：中国矿业大学,2003.
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |