冶金离子熔体电导率测定技术进展
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摘要
冶金离子熔体是高温电解冶炼、金属精炼等冶炼过程中的反应介质或多相反应的直接参与者。为保证冶炼过程的顺利进行,冶金离子熔体必须具有适宜的物理化学性质。电导率作为冶金离子熔体的一项重要物理化学性质,在冶金生产过程中对控制产品质量、生产效率、能耗和成本等具有重要意义。此外,电导率与离子熔体结构、离子迁移、导电机理和电极反应机理息息相关,研究冶金离子熔体的电导率也有助于研究冶金的基础理论。因此,电导率对冶金领域的重要性不言而喻,它的精确测定一直以来都是冶金工作者关注的一个重点。液态电解质电导率的测定通常在电导池中进行。但冶金离子熔体温度往往很高,导致电导率的测定存在困难,诸如合适的电导池的构建以及电极材料的选择。在测定原理的指导下,已经发展了多种电导率测定技术,目前测量冶金离子熔体电导率常用的方法有交流二电极法、交流四电极法、连续改变电导池常数法(CVCC法)和同轴圆筒法。交流二电极法和交流四电极法由于其电导池结构相对简单,电极、电导池材料获得容易,适用范围广,在监管生产过程中或在需要快速获得电导率数据的情况下得到了广泛应用。相对于交流二电极,交流四电极的优越性在于将测定电压和电流的电极分开,测定电压的电极上几乎没有电流经过,无需考虑电极和引线电阻。但这两种方法在电导池结构上均存在缺陷,使得测试的精度难以把握。CVCC法和同轴圆筒法相对于前两者,在电导池结构上的优越性使得它们的测定精度较高,可在对精度要求较高的情况下使用。但它们的电导池结构通常较为复杂,CVCC法在某些条件下需要特定的材料才能满足实验要求,从而导致实验成本高;同轴圆筒法尽管在电极对中的条件下具备免标定的优势,但高温下依然存在电极变形的影响,同时该法的电导率测试范围受到实验条件下能构建的电导池大小的限制。本文主要对上述四种电导率测定方法的原理、技术优缺点、操作、使用条件及测定效果等进行了归纳总结;此外还对四种电导率测定方法之间的联系进行了简单分析,以期指导实验室电导率的测定。
Metallurgical ionic melt usually acts as the reaction medium or direct participant of heterogeneous smelting reaction involving electro-winning and metal refining,etc. at high temperature. Aiming at ensuring the smooth process of smelting,metallurgical ionic melt has to possess appropriate physical and chemical properties. As an important physicochemical property of metallurgical ionic melt,the electrical conductivity plays a dominant role in controlling the quality of products,production efficiency,energy consumption,cost during metallurgical production. In addition,the electrical conductivity is closely related to the structure of ionic melt,ionic migration,conductive mechanism and electrode reaction mechanism. The study of the electrical conductivity of metallurgical ionic melt is also contributed to the exploration of basic theories concerning metallurgy. Accordingly,it is of great significance to study the electrical conductivity in metallurgical field,and its accurate determination has always been a focus of attention of metallurgical researchers.Measurement of electrical conductivity of liquid electrolyte is commonly performed in a conductance cell. However,metallurgical ionic melt often holds high temperature,which brings about difficulties in determination,including the construction of appropriate conductance cell and the choice of electrode material. Under the guidance of measurement principle,diverse measurement techniques of conductivity have been developed. At present,the commonly used approaches for measuring the electrical conductivity of metallurgical ion melt consist of AC two-electrode technique,AC four-electrode technique,continuously varying cell constant( CVCC) technique and coaxial cylinders technique. AC two-electrode and AC four-electrode techniques hold widespread applications,owing to their relatively simple structure of the conductance cell,and the ease of obtaining the materials of the electrode and the conductive cell. Hence,it is widely used for monitoring the production process and the quick measurement of the conductivity data. Compared with AC two-electrode technique,the superiority of four-electrode technique lies in the separation of the electrodes of measuring voltage and current,and there is almost no current passing through the electrodes for measuring voltage,thus the consideration of electrodes and lead wires resistance can be avoided. Nevertheless,the two methods suffer from defects in the structure of the conductance cell,which makes the measurement accuracy difficult to grasp. The CVCC and the coaxial cylinders techniques are superior to the above two methods in the structure of the conductance cell,which makes them possess higher measurement accuracy and capable of applying in the case of higher precision requirements. Unfortunately,the structure of their conductance cell is usually rather complicated. Moreover,the CVCC technique requires specific materials to satisfy the experimental requirements under certain conditions,which leads to a higher experimental cost. Although the coaxial cylinders technique exhibits the advantage of calibration-free under the condition of electrode centered,the influence of the electrode deformation still exists at high temperature. Meanwhile,the measurement range of the electrical conductivity is limited by the size of the conductance cell that can be constructed under experimental conditions.In this article,the experimental technical experiences of the above four methods including measurement principles,relative merits of the techniques,operation and working conditions are summarized and compared; additionally,the relationship among the above four methods is also analyzed briefly,for the sake of providing guidance for measuring electrical conductivity of metallurgical ionic melt in laboratory.
Metallurgical ionic melt usually acts as the reaction medium or direct participant of heterogeneous smelting reaction involving electro-winning and metal refining,etc. at high temperature. Aiming at ensuring the smooth process of smelting,metallurgical ionic melt has to possess appropriate physical and chemical properties. As an important physicochemical property of metallurgical ionic melt,the electrical conductivity plays a dominant role in controlling the quality of products,production efficiency,energy consumption,cost during metallurgical production. In addition,the electrical conductivity is closely related to the structure of ionic melt,ionic migration,conductive mechanism and electrode reaction mechanism. The study of the electrical conductivity of metallurgical ionic melt is also contributed to the exploration of basic theories concerning metallurgy. Accordingly,it is of great significance to study the electrical conductivity in metallurgical field,and its accurate determination has always been a focus of attention of metallurgical researchers.Measurement of electrical conductivity of liquid electrolyte is commonly performed in a conductance cell. However,metallurgical ionic melt often holds high temperature,which brings about difficulties in determination,including the construction of appropriate conductance cell and the choice of electrode material. Under the guidance of measurement principle,diverse measurement techniques of conductivity have been developed. At present,the commonly used approaches for measuring the electrical conductivity of metallurgical ion melt consist of AC two-electrode technique,AC four-electrode technique,continuously varying cell constant( CVCC) technique and coaxial cylinders technique. AC two-electrode and AC four-electrode techniques hold widespread applications,owing to their relatively simple structure of the conductance cell,and the ease of obtaining the materials of the electrode and the conductive cell. Hence,it is widely used for monitoring the production process and the quick measurement of the conductivity data. Compared with AC two-electrode technique,the superiority of four-electrode technique lies in the separation of the electrodes of measuring voltage and current,and there is almost no current passing through the electrodes for measuring voltage,thus the consideration of electrodes and lead wires resistance can be avoided. Nevertheless,the two methods suffer from defects in the structure of the conductance cell,which makes the measurement accuracy difficult to grasp. The CVCC and the coaxial cylinders techniques are superior to the above two methods in the structure of the conductance cell,which makes them possess higher measurement accuracy and capable of applying in the case of higher precision requirements. Unfortunately,the structure of their conductance cell is usually rather complicated. Moreover,the CVCC technique requires specific materials to satisfy the experimental requirements under certain conditions,which leads to a higher experimental cost. Although the coaxial cylinders technique exhibits the advantage of calibration-free under the condition of electrode centered,the influence of the electrode deformation still exists at high temperature. Meanwhile,the measurement range of the electrical conductivity is limited by the size of the conductance cell that can be constructed under experimental conditions.In this article,the experimental technical experiences of the above four methods including measurement principles,relative merits of the techniques,operation and working conditions are summarized and compared; additionally,the relationship among the above four methods is also analyzed briefly,for the sake of providing guidance for measuring electrical conductivity of metallurgical ionic melt in laboratory.
引文
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4 Dai X,Zhang C F.Nonferrous Metals,2005(4),2(in Chinese).戴曦,张传福.有色金属(冶炼部分),2005(4),2.
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10 Korenko M,Pri■ák J,■imko F.Chemical Papers,2013,67(10),1350.26
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16 Barati M,Coley K S.Metallurgical&Materials Transactions B,2006,37(B),41.
17 Apisarov A P,Kryukovskii V A,Zaikov Y P,et al.Russian Journal of Electrochemistry,2007,43(8),870.
18 Dedyukhin A,Apisarov A,Tkacheva O,et al.ECS Transactions,2009,16(49),317.
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20 Mitchell A,Cameron J.Metallurgical&Materials Transactions B,1971,2(12),3361.
21 Bacon G,Mitchell A,Nishizaki R M.Metallurgical Transactions,1972,3(3),631.
22 Hu X W,Wang Z W,Gao B L,et al.Journal of Northeastern University(Natural Science),2008,29(9),1294(in Chinese).胡宪伟,王兆文,高炳亮,等.东北大学学报(自然科学版),2008,29(9),1294.
23 Wang Z W,Hu X W,Gao B L,et al.Journal of Northeastern University(Natural Science),2006,27(7),786(in Chinese).王兆文,胡宪伟,高炳亮,等.东北大学学报(自然科学版),2006,27(7),786.
24 Pal U B,Macdonald C J,Chiang E,et al.Metallurgical&Materials Transactions B,2001,32(6),1119.
25 Fellner P,Midtlyng S,Sterten A,et al.Journal of Applied Electrochemistry,1993,23(1),78.
26 Fellner P,Kobbeltvedt O,Sterten ■,et al.Electrochimica Acta,1993,38(4),589.
27 Hive■ J,Thonstad J,Sterten ■,et al.Metallurgical&Materials Transactions B,1996,27(2),255.
28 Híve■ J,Thonstad J.Electrochimica Acta,2004,49(28),5111.
29 Kubiňáková E,Híve■ J,Danielik V.Acta Chimica Slovaca,2016,9(2),141.
30 Xie H W,Wang J X,Zhai Y C,Hu X Y,et al.The Open Materials Science Journal,2011,5(1),83.
31 Liang L K,Guo Z W,Wang Y Z,et al.Journal of Northeastern University(Natural Science),1985(3),74(in Chinese).梁连科,郭仲文,王云志,等.东北大学学报(自然科学版),1985(3),74.
32 Yim E W,Feinleib M.Journal of the Electrochemical Society,1957,104(10),622.
33 Redkin A,Zaikov Y,Tingaev P,et al.Ionics,2013,19(12),1949.
34 Jia Z.Electrochimcal measurement method,Chemical Industry Press,China,2006(in Chinese).贾铮.电化学测量方法,化学工业出版社,2006.
35 Hills G J,Djordjevic'S.Electrochimica Acta,1968,13(7),1721.
36 Tomkins R P T,Janz G J,Andalaft E.Journal of the Electrochemical Society,1970,117(7),125.
37 Ogino K,Hara S.Tetsu-to-Hagane,1977,63(13),2141.
38 Wang X W,Ray D P,Tabereaux A T.In:Light Metals.San Diego,1992,pp.481.
39 Liao C F,Wang K,Wang X,et al.Nonferrous Metals Science&Engineering,2013(5),19(in Chinese).廖春发,王坤,王旭,等.有色金属科学与工程,2013(5),19.
40 Voronin B M,PrisyazhnyiV D,et al.Ukrainskii Khimicheskii Zhurnal,1980(46),229.
41 Schiefelbein S L,Sadoway D R.Metallurgical&Materials Transactions B,1997,28(6),1141.
42 Schiefelbein S L.A new technique to measure the electrical properties of molten oxides.PhD.Thesis,Massachusetts Institute of Technology,USA,1996.
43 Schiefelbein S L.High Temperature Materials&Processes,2001,20(3-4),247.
44 Verein Deutscher Eisenhüttenleute(VDEh).Slag atlas,Verlag Stahleisen Gmb H,Germany,1995.
45 Fried N A.Electrical properties of binary solutions of molten titanium dioxide-barium oxide.PhD.Thesis,Massachusetts Institute of Technology,USA,1996.(责任编辑向秀洮)
2 Robbins G D.Journal of the Electrochemical Society,1969,116(6),813.
3 Malki M,Echegut P.Journal of Non-Crystalline Solids,2003,323(1-3),131.
4 Dai X,Zhang C F.Nonferrous Metals,2005(4),2(in Chinese).戴曦,张传福.有色金属(冶炼部分),2005(4),2.
5 Hara S,Hashimoto H,Ogino K.Transactions of the Iron and Steel Institute of Japan,1983(23),1053.
6 Ogino K,Hashimoto H,Hara S.Tetsu-to-Hagane,2010,64(2),225.
7 Kim K B,Sadoway D R.Journal of the Electrochemical Society,1992,139(139),1027.
8 Kim K B.Journal of the Electrochemical Society,1992,139(8),2128.
9 Wang S,Li G,Lou T,et al.ISIJ International,2007,39(11),1116.
10 Korenko M,Pri■ák J,■imko F.Chemical Papers,2013,67(10),1350.26
11 Segers L,Fontana A,Winand R.Canadian Metallurgical Quarterly,2014,22(4),429.
12 Sun C,Guo X.Transactions of Nonferrous Metals Society of China,2011,21(7),1648.
13 Simonnet C,Phalippou J,Malki M,et al.Review of Scientific Instruments,2003,74(5),2805.
14 Macdonald C J,Huang G,Pal U B,et al.Office of scientific&technical information technical reports,U.S.Department of Energy,USA,2000.
15 Hundermark R J,Jahanshahi S,Sun S.In:International Conference on Molten Slags,Fluxes and Salts.Cape Town,2004,pp.487.
16 Barati M,Coley K S.Metallurgical&Materials Transactions B,2006,37(B),41.
17 Apisarov A P,Kryukovskii V A,Zaikov Y P,et al.Russian Journal of Electrochemistry,2007,43(8),870.
18 Dedyukhin A,Apisarov A,Tkacheva O,et al.ECS Transactions,2009,16(49),317.
19 Apisarov A A,Redkin A A,Zaikov Y P,et al.Journal of Chemical&Engineering Data,2011,56(12)4733.
20 Mitchell A,Cameron J.Metallurgical&Materials Transactions B,1971,2(12),3361.
21 Bacon G,Mitchell A,Nishizaki R M.Metallurgical Transactions,1972,3(3),631.
22 Hu X W,Wang Z W,Gao B L,et al.Journal of Northeastern University(Natural Science),2008,29(9),1294(in Chinese).胡宪伟,王兆文,高炳亮,等.东北大学学报(自然科学版),2008,29(9),1294.
23 Wang Z W,Hu X W,Gao B L,et al.Journal of Northeastern University(Natural Science),2006,27(7),786(in Chinese).王兆文,胡宪伟,高炳亮,等.东北大学学报(自然科学版),2006,27(7),786.
24 Pal U B,Macdonald C J,Chiang E,et al.Metallurgical&Materials Transactions B,2001,32(6),1119.
25 Fellner P,Midtlyng S,Sterten A,et al.Journal of Applied Electrochemistry,1993,23(1),78.
26 Fellner P,Kobbeltvedt O,Sterten ■,et al.Electrochimica Acta,1993,38(4),589.
27 Hive■ J,Thonstad J,Sterten ■,et al.Metallurgical&Materials Transactions B,1996,27(2),255.
28 Híve■ J,Thonstad J.Electrochimica Acta,2004,49(28),5111.
29 Kubiňáková E,Híve■ J,Danielik V.Acta Chimica Slovaca,2016,9(2),141.
30 Xie H W,Wang J X,Zhai Y C,Hu X Y,et al.The Open Materials Science Journal,2011,5(1),83.
31 Liang L K,Guo Z W,Wang Y Z,et al.Journal of Northeastern University(Natural Science),1985(3),74(in Chinese).梁连科,郭仲文,王云志,等.东北大学学报(自然科学版),1985(3),74.
32 Yim E W,Feinleib M.Journal of the Electrochemical Society,1957,104(10),622.
33 Redkin A,Zaikov Y,Tingaev P,et al.Ionics,2013,19(12),1949.
34 Jia Z.Electrochimcal measurement method,Chemical Industry Press,China,2006(in Chinese).贾铮.电化学测量方法,化学工业出版社,2006.
35 Hills G J,Djordjevic'S.Electrochimica Acta,1968,13(7),1721.
36 Tomkins R P T,Janz G J,Andalaft E.Journal of the Electrochemical Society,1970,117(7),125.
37 Ogino K,Hara S.Tetsu-to-Hagane,1977,63(13),2141.
38 Wang X W,Ray D P,Tabereaux A T.In:Light Metals.San Diego,1992,pp.481.
39 Liao C F,Wang K,Wang X,et al.Nonferrous Metals Science&Engineering,2013(5),19(in Chinese).廖春发,王坤,王旭,等.有色金属科学与工程,2013(5),19.
40 Voronin B M,PrisyazhnyiV D,et al.Ukrainskii Khimicheskii Zhurnal,1980(46),229.
41 Schiefelbein S L,Sadoway D R.Metallurgical&Materials Transactions B,1997,28(6),1141.
42 Schiefelbein S L.A new technique to measure the electrical properties of molten oxides.PhD.Thesis,Massachusetts Institute of Technology,USA,1996.
43 Schiefelbein S L.High Temperature Materials&Processes,2001,20(3-4),247.
44 Verein Deutscher Eisenhüttenleute(VDEh).Slag atlas,Verlag Stahleisen Gmb H,Germany,1995.
45 Fried N A.Electrical properties of binary solutions of molten titanium dioxide-barium oxide.PhD.Thesis,Massachusetts Institute of Technology,USA,1996.(责任编辑向秀洮)