AU2013275996A1

AU2013275996A1 - Inert alloy anode used for aluminum electrolysis and preparation method therefor

Info

Publication number: AU2013275996A1
Application number: AU2013275996A
Authority: AU
Inventors: Yulin FANG; Songtao SUN
Original assignee: INNER MONGOLIA UNITED IND CO Ltd
Current assignee: Inner Mongolia United Industrial Co Ltd
Priority date: 2012-06-11
Filing date: 2013-05-30
Publication date: 2015-01-22
Anticipated expiration: 2033-05-30
Also published as: US20150159287A1; EP2860291B1; AU2013275996B2; EP2860291A1; AP2015008186A0; IN2015DN00217A; EA201492227A1; CA2876336C; ZA201409511B; WO2013185539A1; KR20150022994A; EP2860291A4; CA2876336A1; EA030951B1

Abstract

An inert alloy anode used for aluminum electrolysis. The anode has Fe and Cu as the main constituents and comprises Sn. The addition of the Sn metal is conducive to the formation of a layer of oxidized film having a great antioxidant activity and structural stability on the surface of the inert alloy anode, and is conducive to an increase in the corrosion resistance of the anode. On this basis, the constituents of the inert alloy anode also comprise Ni, Al, and Y. The addition of the Al metal prevents the main metal constituents from being oxidized, the addition of the Y metal controls the alloy to provide a required polymorph in a preparation process, thus achieving the goal of anti-oxidation. The inert alloy anode having Fe and Cu as the main constituents has a low over-voltage, high electric conductivity, and reduced costs, and is applicable in the aluminum electrolysis industry.

Description

1/12 Description INERT ALLOY ANODE FOR ALUMINUM ELECTROLYSIS AND PREPARING METHOD THEREOF 5 Field of the Invention The present invention relates to an inert alloy anode for aluminum electrolysis and a preparing method thereof, belonging to the field of aluminum electrolysis industry. Background of the Invention 10 Aluminum electrolysis refers to acquisition of aluminum by alumina electrolysis. In the prior art, a traditional Hall-Heroult molten salt aluminum electrolysis process is typically adopted for aluminum electrolysis, this process is featured by use of a cryolite-alumina molten salt electrolysis method in which cryolite Na3AIF6 fluoride salt melt is taken as flux, A1203 is dissolved in the fluoride salt, a carbon body is taken as an anode, aluminum liquid is taken as a cathode, and electrolytic aluminum is obtained by 15 performing electrochemical reaction at the anode and cathode of the electrolytic cell at a high temperature ranging from 9400C to 9600C after a strong direct current is introduced. In the traditional aluminum electrolysis process, a carbon anode is ceaselessly consumed in the electrolysis process, thus constant replacement for the carbon anode is required; moreover, carbon dioxide, carbon monoxide, toxic fluorine hydride and other waste gases are continuously generated at the anode during alumina 20 electrolysis, emission of these gases into environment will be harmful to environment and health of human and livestock, so that the waste gases generated by aluminum electrolysis need to be purified before emission, which accordingly increases the investment cost of the alumina electrolysis production process. Consumption of the anode material in the process of aluminum electrolysis is mainly caused by 25 oxidization reaction, in the electrolysis process, of the carbon anode material used in the traditional Hall Heroult process. Therefore, many domestic and foreign researchers have commenced the study on anode material in order to reduce consumption of the anode material in the process of aluminum electrolysis and simultaneously lessen waste gas emission. For example, disclosed in Chinese patent document CN102230189A is a metal ceramic inert anode material for aluminum electrolysis, which is 30 obtained by the steps of preparing an NiO-NiFe2O4 metal ceramic matrix from raw materials including Ni2O3 and Fe2O3 and then adding metal copper powder and nano NiO, and which has an electric conductivity as high as 1020-1 -cm-1. In the above art, the anode material with metal ceramic as the matrix, though hardly reacting with electrolyte, is large in resistance and high in overvoltage, which results in large power consumption of the process and high cost in the process of aluminum electrolysis; 35 furthermore, the anode material with metal ceramic as the matrix has poor thermal shock resistance and consequently is liable to brittlement during use; and in addition, the processability in use of the anode made from the above materials is poor just because the anode material having the metal ceramic matrix is liable to brittlement, as a result, the anode in any shape cannot be obtained. To solve the problem that the anode material having the metal ceramic matrix is low in electric 40 conductivity and brittle in structure, some researchers have brought forward use of alloy metals as the anode material, in order to improve the electric conductivity of the anode material and simultaneously improve the processability of the anode material. Disclosed in Chinese patent document CN1443877A is an inert anode material applied to aluminum, magnesium, rare earth and other electrolysis industries, this material is formed by binary or multi-element alloy composed of chromium, nickel, ferrum, cobalt, 45 titanium, copper, aluminum, magnesium and other metals, and the preparation method thereof is a method of smelting or powder metallurgy. The prepared anode material is good in electric and thermal conductivity and generates oxygen in the electrolysis process, wherein in Example 1, an anode is made of the alloy material composed of 37wt% of cobalt, 18wt% of copper, 19wt% of nickel, 23wt% of ferrum and 3wt% of silver and is used for aluminum electrolysis, the anode has a current density of 1.0A/cm2 in 50 the electrolysis process at 850 0 C and the cell voltage is steadily maintained within a range from 4.1V to 4.5V in the electrolysis process, the prepared aluminum has a purity of 98.35%.

2/12 In the case that the alloy composed of a plurality of metals, including chromium, nickel, ferrum, cobalt, titanium, copper, aluminum and magnesium, is used as the anode material for aluminum electrolysis in the above art, this alloy anode material has higher electric conductivity than the anode ceramic matrix anode material, can be processed in any shape by a smelting or powder metallurgy method and is hardly 5 consumed in the electrolysis process compared with the carbon anode material. However, a large amount of expensive metal materials are used in preparation of the alloy anode in the above art to result in high cost of the anode material, and thus this alloy anode fails to meet the demand on industrial cost; moreover, the alloy anode prepared from the above metal components is low in electric conductivity and high in overvoltage, so that the power consumption of the process is increased, thus the alloy anode 10 cannot meet the needs of the aluminum electrolysis process. In addition, an oxide film is generated on the surface of the prepared alloy anode in the prior art, and if this oxide film is destroyed, the anode material exposed to the surface will be oxidized as a new oxide film. The oxide film on the surface of the alloy anode in the above art has low oxidization resistance and is further liable to oxidization reaction to generate products that are likely to be corroded by electrolyte, 15 and the oxide film with low stability is liable to fall off the anode electrode in the electrolysis process; after the previous oxide film is corroded or falls off, the material of the alloy anode exposed to the surface will create a new oxide film by reaction with oxygen, such replacement between new and old oxide films results in continuous consumption and poor corrosion resistance of the anode material as well as short service life of electrodes; furthermore, the corroded or falling oxide film enters into liquid aluminum in the 20 electrolysis process of alumina to degrade the purity of the final product aluminum, as a result, the manufactured aluminum product cannot meet the demand of national standards and accordingly cannot be directly used as a finished product. Summary of the Invention 25 The first technical problem to be solved by the present invention is that the alloy anode in the prior art is expensive in metal materials used, high in process cost, low in electric conductivity and high in overvoltage, as a result, power consumption of the process is increased; therefore, provided is an inert alloy anode for aluminum electrolysis with low cost and overvoltage, and a preparing method thereof. Simultaneously, the second technical problem to be solved by the present invention is that, an oxide film 30 on the surface of the alloy anode in the prior art is low in oxidation resistance and liable to fall off, which leads to continuous consumption of the alloy anode and poor corrosion resistance, furthermore, the corroded or falling oxide film enters into liquid aluminum to degrade the purity of the final product aluminum; therefore, provided is an inert alloy anode for aluminum electrolysis, which is strong in oxidization resistance of the oxide film formed on the surface and not liable to fall off so as to improve the 35 corrosion resistance thereof and the purity of the product aluminum, and a preparing method of the inert alloy anode. To solve the aforementioned technical problems, the present invention provides an inert alloy anode for aluminum electrolysis, which contains Fe and Cu as primary components, and further contains Sn. The mass ratio of Fe to Cu to Sn is (23-40): (36-60): (0.2-5) or (40.01-80): (0.01-35.9): (0.01-0.19). 40 The inert alloy anode further contains Ni. The mass ratio of Fe to Cu to Ni to Sn is (23-40): (36-60): (14-28): (0.2-5) or (40.01-80): (0.01-35.9): (28.1-70): (0.01-0.19). The inert alloy anode is composed of Fe, Cu, Ni and Sn, wherein the content of Fe is 23-40wt%, the content of Cu is 36-60wt%, the content of Ni is 14-28wt% and the content of Sn is 0.2-5wt%, or the 45 content of Fe is 40.01-71.88wt%, the content of Cu is 0.01 -31.88wt%, the content of Ni is 28.1-59.97wt% and the content of Sn is 0.01 -0.19wt%. The inert alloy anode further contains Al. The inert alloy anode is composed of Fe, Cu, Ni, Sn and Al, wherein the content of Fe is 23-40wt%, the content of Cu is 36-60wt%, the content of Ni is 14-28wt%, the content of Al is more than zero and less 50 than or equal to 4wt% and the content of Sn is 0.2-5wt%, or the content of Fe is 40.01-71.88wt%, the 3/12 content of Cu is 0.01-31.88wt%, the content of Ni is 28.1 -59.97wt%, the content of Al is more than zero and less than or equal to 4wt% and the content of Sn is 0.01-0.19wt%. The inert alloy anode further contains Y. The inert alloy anode is composed of Fe, Cu, Ni, Sn, Al and Y, wherein the content of Fe is 23-40wt%, 5 the content of Cu is 36-60wt%, the content of Ni is 14-28wt%, the content of Al is more than zero and less than or equal to 4wt%, the content of Y is more than zero and less than or equal to 2wt% and the content of Sn is 0.2-5wt%, or the content of Fe is 40.01-71.88wt%, the content of Cu is 0.01 -31.88wt%, the content of Ni is 28.1-59.97wt%, the content of Al is more than zero and less than or equal to 4wt%, the content of Y is more than zero and less than or equal to 2wt% and the content of Sn is 0.01 -0.19wt%. 10 A preparing method of the inert alloy anode comprises the following steps: melting and uniformly mixing the metals Fe, Cu and Sn, and then rapidly casting and cooling the mixture to obtain the inert alloy anode; or, melting the metals Fe, Cu and Sn at first, then adding and melting the metal Al or Y, and uniformly mixing, or adding and melting the metal Al at first, then adding and melting the metal Y, uniformly mixing, 15 and rapidly casting and cooling the mixture to obtain the inert alloy anode; or, melting and mixing the metals Fe, Cu, Ni and Sn and then casting the mixture to obtain the inert alloy anode; or, melting the metals Fe, Cu, Ni and Sn at first, then adding and melting the metal Al or Y, and uniformly mixing, or adding and melting the metal Al at first, then adding and melting the metal Y, uniformly mixing, 20 and casting the mixture to obtain the inert alloy anode. Compared with the prior art, the inert alloy anode for aluminum electrolysis in the present invention has the beneficial effects below: (1) The inert alloy anode for aluminum electrolysis in the present invention contains Fe and Cu as primary components, and further contains Sn. The inert alloy anode with the above components is low in 25 cost, low in overvoltage and small in power consumption of the aluminum electrolysis process; the anode material is alloy composed of Fe, Cu and Sn, so an oxide film formed on the surface of the inert alloy anode in the electrolysis process is high in oxidation resistance and is hardly corroded by electrolyte, and the formed oxide film is stable and not liable to fall off, therefore, the inert alloy anode is imparted with quite high oxidation resistance and corrosion resistance. It is precisely because of high oxidation 30 resistance and corrosion resistance of the inert alloy anode, impurities entering into liquid aluminum, which are generated by corrosion or falling off of the anode material, are avoided, so as to ensure the purity of aluminum products, that is, the purity of the produced aluminum can reach 99.8%. The following problems are avoided: the alloy anode in the prior art has high cost and overvoltage and large power consumption of process, the oxide film on the alloy surface is low in oxidation resistance and liable to fall 35 off, which leads to continuous consumption of the alloy anode and poor corrosion resistance, furthermore, the corroded or falling oxide film enters into liquid aluminum to degrade the purity of the final product aluminum. (2) The inert alloy anode for aluminum electrolysis in the present invention is composed of Fe, Cu, Ni and Sn, wherein the content of Fe is 23-40wt%, the content of Cu is 36-60wt%, the content of Ni is 14-28wt% 40 and the content of Sn is 0.2-5wt%, or the content of Fe is 40.01 -71.88wt%, the content of Cu is 0.01 31.88wt%, the content of Ni is 28.1-59.97wt% and the content of Sn is 0.01 -0.19wt%. The alloy anode in the present invention contains Fe and Cu as primary components, their content proportions are high, so the material cost of the inert alloy anode is reduced, meanwhile, the inert alloy anode composed of the aforementioned metal components is high in electric conductivity and has a cell 45 voltage as low as 3.1V to 3.4V, power consumption for aluminum electrolysis is small, the power consumption for per ton of aluminum is not more than 11 OOOkw-h, so the production cost of electrolytic aluminum is low. The following problems are avoided: a large quantity of expensive metal materials are used in the anode material in the prior art, resulting in increase of the anode production cost; the prepared alloy anode is low in electric conductivity, large in power consumption for aluminum electrolysis 50 and increased in cost, and cannot be applied to industrial production. The added metal Ni is capable of promoting firmer combination among other types of metals, and the added metal Sn ensures that an 4/12 oxide film with high oxidization resistance, good corrosion resistance and high stability can be formed on the surface of the inert alloy anode in the electrolysis process. (3) The inert alloy anode for aluminum electrolysis in the present invention is composed of Fe, Cu, Ni, Sn, Al and Y, wherein the content of Fe is 23-40wt%, the content of Cu is 36-60wt%, the content of Ni is 5 14-28wt%, the content of Al is more than zero and less than or equal to 4wt%, the content of Y is more than zero and less than or equal to 2wt% and the content of Sn is 0.2-5wt%, or the content of Fe is 40.01-71.88wt%, the content of Cu is 0.01-31.88wt%, the content of Ni is 28.1 -59.97wt%, the content of Al is more than zero and less than or equal to 4wt%, the content of Y is more than zero and less than or equal to 2wt% and the content of Sn is 0.01-0.19wt%. Similarly, the aforementioned inert alloy anode has 10 the advantages of low material cost and high electric conductivity, in addition, the metal Al contained in the aforementioned inert alloy anode plays a role of oxidization resistance and can serve as a reducing agent for metallothermic reduction reaction with a metal oxide in the inert anode alloy, thus ensure the percentage of the primary components in the inert alloy anode, meanwhile, the added metal Y can be used for controlling a crystal structure for anode material formation in the preparation process of the inert 15 anode, achieving the anti-oxidization purpose. (4) The inert alloy anode for aluminum electrolysis in the present invention has a melting point of 1360 13860C, a specific resistivity of 68-76.8pO-cm at 200C and a density of 8.1-8.3g/cm3. The prepared inert alloy anode has a quite high melting point and accordingly can meet the demand of aluminum electrolysis on high temperature environment; furthermore, the aforementioned inert alloy anode has a 20 quite low overvoltage, so power consumption of the aluminum electrolysis process can be reduced; the prepared inert alloy anode is even in texture and has a density within a range from 8.1 g/cm3 to 8.3g/cm3, in this way, stable service property of the inert alloy anode is guaranteed. (5) The preparing method of the inert alloy anode comprises the following steps: melting and uniformly mixing the metals Fe, Cu and Sn, and then rapidly casting and cooling the mixture to obtain the inert 25 alloy anode; or, melting the metals Fe, Cu and Sn at first, then adding and melting the metal Al or Y, and uniformly mixing, or adding and melting the metal Al at first, then adding and melting the metal Y, uniformly mixing, and rapidly casting and cooling the mixture to obtain the inert alloy anode; or, melting and mixing the metals Fe, Cu, Ni and Sn and then casting the mixture to obtain the inert alloy anode; or, melting the metals Fe, Cu, Ni and Sn at first, then adding and melting the metal Al or Y, and uniformly 30 mixing, or adding and melting the metal Al at first, then adding and melting the metal Y, uniformly mixing, and casting the mixture to obtain the inert alloy anode. The aforementioned inert alloy anode is simple in preparation process and can be prepared in any shape according to the actual needs. During preparation of the alloy containing the metals Al and Y, Al is added at first to prevent other molten metal components from being oxidized, and then, Y is added and molten to finally obtain the alloy having a desired crystal 35 form. For more easily understanding the technical solution of the present invention, further description will be made below to the technical solution of the present invention in conjunction with the embodiments. Detailed Description of the Embodiments 40 Embodiment 1 23 parts by weight of Fe metal blocks, 60 parts by weight of Cu metal blocks and 0.2 parts by weight of Sn metal blocks are molten and then uniformly mixed under high-speed electromagnetic stirring, the mixture is rapidly cast and then rapidly cooled at a speed of 20-100 C/s to obtain an inert alloy anode 1 which is homogeneous in texture. The inert alloy anode has a density of 8.3g/cm3, a specific resistivity of 45 62pO-cm and a melting point of 1400 0 C. Embodiment 2 40 parts by weight of Fe metal blocks, 36 parts by weight of Cu metal blocks and 5 parts by weight of Sn metal blocks are molten and then uniformly mixed under high-speed electromagnetic stirring, the mixture 50 is rapidly cast and then rapidly cooled at a speed of 20-100 0 C/s to obtain an inert alloy anode 2 which is 5/12 homogeneous in texture. The inert alloy anode has a density of 7.8g/cm3, a specific resistivity of 82pO-cm and a melting point of 13690C. Embodiment 3 5 30 parts by weight of Fe metal blocks, 45 parts by weight of Cu metal blocks and 3 parts by weight of Sn metal blocks are molten and then uniformly mixed under high-speed electromagnetic stirring, the mixture is rapidly cast and then rapidly cooled at a speed of 20-1 00C/s to obtain an inert alloy anode 3 which is homogeneous in texture. The inert alloy anode has a density of 7.9g/cm3, a specific resistivity of 86pO-cm and a melting point of 13900C. 10 Embodiment 4 30 parts by weight of Fe metal blocks, 50 parts by weight of Cu metal blocks, 20 parts by weight of Mo and 5 parts by weight of Sn metal blocks are molten and then cast to obtain an inert alloy anode 4. The inert alloy anode has a density of 8.2g/cm3, a specific resistivity of 78pO-cm and a melting point of 15 13700C. Embodiment 5 23 parts by weight of Fe metal blocks, 60 parts by weight of Cu metal blocks, 14 parts by weight of Ni and 3 parts by weight of Sn metal blocks are molten and then cast to obtain an inert alloy anode 5. The 20 inert alloy anode has a density of 8.3g/cm3, a specific resistivity of 68pO-cm and a melting point of 13600C. Embodiment 6 40 parts by weight of Fe metal blocks, 36 parts by weight of Cu metal blocks, 19 parts by weight of Ni 25 and 5 parts by weight of Sn metal blocks are molten and then cast to obtain an inert alloy anode 6. The inert alloy anode has a density of 8.1g/cm3, a specific resistivity of 76.8pO-cm and a melting point of 13860C. Embodiment 7 30 25 parts by weight of Fe metal blocks, 46.8 parts by weight of Cu metal blocks, 28 parts by weight of Ni and 0.2 parts by weight of Sn metal blocks are molten and then cast to obtain an inert alloy anode 7. The inert alloy anode has a density of 8.2g/cm3, a specific resistivity of 72pO-cm and a melting point of 13500C. 35 Embodiment 8 23 parts by weight of Fe metal blocks, 60 parts by weight of Cu metal blocks, 14 parts by weight of Ni and 3 parts by weight of Sn metal blocks are molten and then cast to obtain an inert alloy anode 8. The inert alloy anode has a density of 8.1g/cm3, a specific resistivity of 70pO-cm and a melting point of 13300C. 40 Embodiment 9 40 parts by weight of Fe metal blocks, 36 parts by weight of Cu metal blocks, 19 parts by weight of Ni and 5 parts by weight of Sn metal blocks are molten and then cast to obtain an inert alloy anode 9. The inert alloy anode has a density of 8.2g/cm3, a specific resistivity of 73pO-cm and a melting point of 45 13400C. Embodiment 10 24 parts by weight of Fe metal blocks, 47.8 parts by weight of Cu metal blocks, 28 parts by weight of Ni and 0.2 parts by weight of Sn metal blocks are molten and then cast to obtain an inert alloy anode 10. 50 The inert alloy anode has a density of 8.0g/cm3, a specific resistivity of 74pO-cm and a melting point of 13500C.

6/12 Embodiment 11 30 parts by weight of Fe metal blocks, 41 parts by weight of Cu metal blocks and 5 parts by weight of Sn metal blocks are molten at first, then 3 parts by weight of Al metal blocks are added and sequentially 5 molten, uniform mixing is performed under high-speed electromagnet stirring, and the mixture is rapidly cast and then rapidly cooled to obtain an inert alloy anode 11. The inert alloy anode has a density of 8.1g/cm3, a specific resistivity of 68pO-cm and a melting point of 13700C. Embodiment 12 10 23 parts by weight of Fe metal blocks, 60 parts by weight of Cu metal blocks, 14 parts by weight of Ni and 0.2 parts by weight of Sn metal blocks are molten at first, then 2.8 parts by weight of Al metal blocks are added and sequentially molten, and an inert alloy anode 12 is obtained by casting. The inert alloy anode has a density of 8.4g/cm3, a specific resistivity of 69pO-cm and a melting point of 13400C. 15 Embodiment 13 40 parts by weight of Fe metal blocks, 36 parts by weight of Cu metal blocks, 15 parts by weight of Ni and 5 parts by weight of Sn metal blocks are molten at first, then 4 parts by weight of Al metal blocks are added and sequentially molten, and an inert alloy anode 13 is obtained by casting. The inert alloy anode has a density of 8.15g/cm3, a specific resistivity of 69pO-cm and a melting point of 13690C. 20 Embodiment 14 36 parts by weight of Fe metal blocks, 47 parts by weight of Cu metal blocks, 14 parts by weight of Ni and 2.9 parts by weight of Sn metal blocks are molten at first, then 0.1 parts by weight of Al metal blocks are added and sequentially molten, and an inert alloy anode 14 is obtained by casting. The inert alloy 25 anode has a density of 8.0g/cm3, a specific resistivity of 67.6pO-cm and a melting point of 13790C. Embodiment 15 27 parts by weight of Fe metal blocks, 50 parts by weight of Cu metal blocks and 4 parts by weight of Sn metal blocks are molten at first, then 1 part by weight of Y metal blocks are added and sequentially 30 molten, uniform mixing is performed under high-speed electromagnet stirring, and the mixture is rapidly cast and then rapidly cooled to obtain an inert alloy anode 15. The inert alloy anode has a density of 8.4g/cm3, a specific resistivity of 67pO-cm and a melting point of 1358 0 C. Embodiment 16 35 35 parts by weight of Fe metal blocks, 45 parts by weight of Cu metal blocks, 24 parts by weight of Ni and 4 parts by weight of Sn metal blocks are molten at first, then 2 parts by weight of Y metal blocks are added and sequentially molten, and an inert alloy anode 16 is obtained by casting. The inert alloy anode has a density of 8.1g/cm3, a specific resistivity of 70.9pO-cm and a melting point of 13750C. 40 Embodiment 17 25 parts by weight of Fe metal blocks, 50 parts by weight of Cu metal blocks and 4 parts by weight of Sn metal blocks are molten at first, then 3 parts by weight of Al metal blocks are added and sequentially molten, finally, 1 part by weight of Y metal blocks are added and molten, uniform mixing is performed under high-speed electromagnet stirring, and the mixture is rapidly cast and then rapidly cooled to obtain 45 an inert alloy anode 17. The inert alloy anode has a density of 8.3g/cm3, a specific resistivity of 68.9pO-cm and a melting point of 13810C. Embodiment 18 23 parts by weight of Fe metal blocks, 60 parts by weight of Cu metal blocks, 14 parts by weight of Ni 50 and 0.9 parts by weight of Sn metal blocks are molten at first, then 0.1 parts by weight of Al metal blocks are added and sequentially molten, finally, 2 parts by weight of Y metal blocks are added and molten, 7/12 mixing is performed, and the mixture is cast to obtain an inert alloy anode 18. The inert alloy anode has a density of 8.3g/cm3, a specific resistivity of 68pO-cm and a melting point of 13600C. Embodiment 19 5 40 parts by weight of Fe metal blocks, 36 parts by weight of Cu metal blocks, 14.9 parts by weight of Ni and 5 parts by weight of Sn metal blocks are molten at first, then 4 parts by weight of Al metal blocks are added and sequentially molten, finally, 0.1 parts by weight of Y metal blocks are added and molten, mixing is performed, and the mixture is cast to obtain an inert alloy anode 19. The inert alloy anode has a density of 8.1g/cm3, a specific resistivity of 76.8pO-cm and a melting point of 13860C. 10 Embodiment 20 29 parts by weight of Fe metal blocks, 38.3 parts by weight of Cu metal blocks, 28 parts by weight of Ni and 0.2 parts by weight of Sn metal blocks are molten at first, then 3.5 parts by weight of Al metal blocks are added and sequentially molten, finally, 1 part by weight of Y metal blocks are added and molten, 15 mixing is performed, and the mixture is cast to obtain an inert alloy anode 20. The inert alloy anode has a density of 8.2g/cm3, a specific resistivity of 70pO-cm and a melting point of 13650C. Embodiment 21 40 parts by weight of Fe metal blocks, 36.5 parts by weight of Cu metal blocks, 18 parts by weight of Ni 20 and 3 parts by weight of Sn metal blocks are molten at first, then 1.5 parts by weight of Al metal blocks are added and sequentially molten, finally, 1 part by weight of Y metal blocks are added and molten, mixing is performed, and the mixture is cast to obtain an inert alloy anode 21. The inert alloy anode has a density of 8.1g/cm3, a specific resistivity of 76.8pO-cm and a melting point of 13860C. 25 Embodiment 22 24.3 parts by weight of Fe metal blocks, 59 parts by weight of Cu metal blocks, 14 parts by weight of Ni and 0.2 parts by weight of Sn metal blocks are molten at first, then 2 parts by weight of Al metal blocks are added and sequentially molten, finally, 0.5 parts by weight of Y metal blocks are added and molten, mixing is performed, and the mixture is cast to obtain an inert alloy anode 22. The inert alloy anode has a 30 density of 8.22g/cm3, a specific resistivity of 68.2pO-cm and a melting point of 1360 0 C. In the aforementioned embodiment, 1 part by weight is 10g, and the inert anode alloy resulted from casting can be in any shape as required. Embodiment 23 35 40.01 parts by weight of Fe metal blocks, 35.9 parts by weight of Cu metal blocks and 0.19 parts by weight of Sn metal blocks are molten and then uniformly mixed under high-speed electromagnetic stirring, the mixture is rapidly cast and then rapidly cooled at a speed of 20-100 0 C/s to obtain an inert alloy anode 23 which is homogeneous in texture. The inert alloy anode has a density of 8.2g/cm3, a specific resistivity of 61 pQ-cm and a melting point of 14000C. 40 Embodiment 24 80 parts by weight of Fe metal blocks, 0.01 parts by weight of Cu metal blocks and 0.01 parts by weight of Sn metal blocks are molten and then uniformly mixed under high-speed electromagnetic stirring, the mixture is rapidly cast and then rapidly cooled at a speed of 20-100 C/s to obtain an inert alloy anode 24 45 which is homogeneous in texture. The inert alloy anode has a density of 7.5g/cm3, a specific resistivity of 82pO-cm and a melting point of 13690C. Embodiment 25 60 parts by weight of Fe metal blocks, 25 parts by weight of Cu metal blocks and 0. 1 part by weight of 50 Sn metal blocks are molten and then uniformly mixed under high-speed electromagnetic stirring, the mixture is rapidly cast and then rapidly cooled at a speed of 20-100 C/s to obtain an inert alloy anode 25 8/12 which is homogeneous in texture. The inert alloy anode has a density of 7.9g/cm3, a specific resistivity of 84pO-cm and a melting point of 13900C. Embodiment 26 5 50 parts by weight of Fe metal blocks, 30 parts by weight of Cu metal blocks, 20 parts by weight of Mo and 0.05 parts by weight of Sn metal blocks are molten and then cast to obtain an inert alloy anode 26. The inert alloy anode has a density of 8.4g/cm3, a specific resistivity of 78pO-cm and a melting point of 13700C. 10 Embodiment 27 40.01 parts by weight of Fe metal blocks, 35.9 parts by weight of Cu metal blocks, 70 parts by weight of Ni and 0.01 parts by weight of Sn metal blocks are molten and then cast to obtain an inert alloy anode 27. The inert alloy anode has a density of 8.5g/cm3, a specific resistivity of 68pO-cm and a melting point of 13600C. 15 Embodiment 28 80 parts by weight of Fe metal blocks, 0.01 parts by weight of Cu metal blocks, 28.1 parts by weight of Ni and 0.19 parts by weight of Sn metal blocks are molten and then cast to obtain an inert alloy anode 28. The inert alloy anode has a density of 7.7g/cm3, a specific resistivity of 76.8pO-cm and a melting point of 20 13860C. Embodiment 29 71.88 parts by weight of Fe metal blocks, 0.01 parts by weight of Cu metal blocks, 28.1 parts by weight of Ni and 0.01 parts by weight of Sn metal blocks are molten and then cast to obtain an inert alloy anode 25 29. The inert alloy anode has a density of 8.2g/cm3, a specific resistivity of 72pO-cm and a melting point of 13500C. Embodiment 30 40.01 parts by weight of Fe metal blocks, 31.88 parts by weight of Cu metal blocks, 28.1 parts by weight 30 of Ni and 0.01 parts by weight of Sn metal blocks are molten and then cast to obtain an inert alloy anode 30. The inert alloy anode has a density of 8.1g/cm3, a specific resistivity of 70pO-cm and a melting point of 13300C. Embodiment 31 35 40 parts by weight of Fe metal blocks, 0.02 parts by weight of Cu metal blocks, 59.97 parts by weight of Ni and 0.01 parts by weight of Sn metal blocks are molten and then cast to obtain an inert alloy anode 31. The inert alloy anode has a density of 8.2g/cm3, a specific resistivity of 73pO-cm and a melting point of 13400C. 40 Embodiment 32 45 parts by weight of Fe metal blocks, 4.81 parts by weight of Cu metal blocks, 50 parts by weight of Ni and 0.19 parts by weight of Sn metal blocks are molten and then cast to obtain an inert alloy anode 32. The inert alloy anode has a density of 8.0g/cm3, a specific resistivity of 74pO-cm and a melting point of 13500C. 45 Embodiment 33 60 parts by weight of Fe metal blocks, 35.9 parts by weight of Cu metal blocks and 0.1 parts by weight of Sn metal blocks are molten at first, then 4 parts by weight of Al metal blocks are added and sequentially molten, uniformly mixing is performed under high-speed electromagnetic stirring, and the mixture is 50 rapidly cast and then rapidly cooled to obtain an inert alloy anode 33. The inert alloy anode has a density of 8.1g/cm3, a specific resistivity of 68pO-cm and a melting point of 1370C.

9/12 Embodiment 34 40.01 parts by weight of Fe metal blocks, 27.7 parts by weight of Cu metal blocks, 28.1 parts by weight of Ni and 0.19 parts by weight of Sn metal blocks are molten at first, then 4 parts by weight of Al metal 5 blocks are added and sequentially molten, and an inert alloy anode 34 is obtained by casting. The inert alloy anode has a density of 8.4g/cm3, a specific resistivity of 69pO-cm and a melting point of 13400C. Embodiment 35 71.88 parts by weight of Fe metal blocks, 0.005 parts by weight of Cu metal blocks, 28.1 parts by weight 10 of Ni and 0.01 parts by weight of Sn metal blocks are molten at first, then 0.005 parts by weight of Al metal blocks are added and sequentially molten, and an inert alloy anode 35 is obtained by casting. The inert alloy anode has a density of 8.15g/cm3, a specific resistivity of 69pO-cm and a melting point of 13690C. 15 Embodiment 36 40.01 parts by weight of Fe metal blocks, 31.88 parts by weight of Cu metal blocks, 25.01 parts by weight of Ni and 0.1 parts by weight of Sn metal blocks are molten at first, then 3 parts by weight of Al metal blocks are added and sequentially molten, and an inert alloy anode 36 is obtained by casting. The inert alloy anode has a density of 8.0g/cm3, a specific resistivity of 67.6pO-cm and a melting point of 20 13790C. Embodiment 37 66 parts by weight of Fe metal blocks, 31.88 parts by weight of Cu metal blocks and 0.01 parts by weight of Sn metal blocks are molten at first, then 2 parts by weight of Y metal blocks are added and 25 sequentially molten, uniformly mixing is performed under high-speed electromagnetic stirring, and the mixture is rapidly cast and then rapidly cooled to obtain an inert alloy anode 37. The inert alloy anode has a density of 8.4g/cm3, a specific resistivity of 67pO-cm and a melting point of 13580C. Embodiment 38 30 40 parts by weight of Fe metal blocks, 0.01 parts by weight of Cu metal blocks, 59.97 parts by weight of Ni and 0.01 parts by weight of Sn metal blocks are molten at first, then 0.01 parts by weight of Y metal blocks are added and sequentially molten, and an inert alloy anode 38 is obtained by casting. The inert alloy anode has a density of 8.1g/cm3, a specific resistivity of 70.9pO-cm and a melting point of 1375 0 C. 35 Embodiment 39 62 parts by weight of Fe metal blocks, 31.88 parts by weight of Cu metal blocks and 0.19 parts by weight of Sn metal blocks are molten at first, then, 4 parts by weight of Al metal blocks are added and sequentially molten, finally, 2 parts by weight of Y metal blocks are added and molten, uniform mixing is performed under high-speed electromagnet stirring, and the mixture is rapidly cast and then rapidly 40 cooled to obtain an inert alloy anode 39. The inert alloy anode has a density of 8.3g/cm3, a specific resistivity of 68.9pO-cm and a melting point of 13810C. Embodiment 40 40 parts by weight of Fe metal blocks, 25.7 parts by weight of Cu metal blocks, 28.1 parts by weight of Ni 45 and 0.19 parts by weight of Sn metal blocks are molten at first, then 4 parts by weight of Al metal blocks are added and sequentially molten, finally, 2 parts by weight of Y metal blocks are added and molten, mixing is performed, and the mixture is cast to obtain an inert alloy anode 40. The inert alloy anode has a density of 8.3g/cm3, a specific resistivity of 68pO-cm and a melting point of 13600C. 50 Embodiment 41 10/12 71.88 parts by weight of Fe metal blocks, 0.005 parts by weight of Cu metal blocks, 28.1 parts by weight of Ni and 0.01 parts by weight of Sn metal blocks are molten at first, then, 0.002 parts by weight of Al metal blocks are added and sequentially molten, finally, 0.003 parts by weight of Y metal blocks are added and molten, mixing is performed, and the mixture is cast to obtain an inert alloy anode 41. The 5 inert alloy anode has a density of 8.1g/cm3, a specific resistivity of 76.8pO-cm and a melting point of 13860C. Embodiment 42 36.92 parts by weight of Fe metal blocks, 31.88 parts by weight of Cu metal blocks, 28.1 parts by weight 10 of Ni and 0.1 parts by weight of Sn metal blocks are molten at first, then 1 part by weight of Al metal blocks are added and sequentially molten, finally, 2 parts by weight of Y metal blocks are added and molten, mixing is performed, and the mixture is cast to obtain an inert alloy anode 42. The inert alloy anode has a density of 8.2g/cm3, a specific resistivity of 70pO-cm and a melting point of 13650C. 15 Embodiment 43 39.81 parts by weight of Fe metal blocks, 0.01 parts by weight of Cu metal blocks, 59.97 parts by weight of Ni and 0.01 parts by weight of Sn metal blocks are molten at first, then 0.1 parts by weight of Al metal blocks are added and sequentially molten, finally, 0.1 parts by weight of Y metal blocks are added and molten, mixing is performed, and the mixture is cast to obtain an inert alloy anode 43. The inert alloy 20 anode has a density of 8.1g/cm3, a specific resistivity of 76.8pO-cm and a melting point of 13860C. Embodiment 44 45 parts by weight of Fe metal blocks, 24.4 parts by weight of Cu metal blocks, 29 parts by weight of Ni and 0.1 parts by weight of Sn metal blocks are molten at first, then 1 part by weight of Al metal blocks are 25 added and sequentially molten, finally, 0.5 parts by weight of Y metal blocks are added and molten, mixing is performed, and the mixture is cast to obtain an inert alloy anode 44. The inert alloy anode has a density of 8.22g/cm3, a specific resistivity of 68.2pO-cm and a melting point of 13600C. In the aforementioned embodiments 23-44, 1 part by weight is 100g, and the inert anode alloy resulted from casting can be in any shape as required. 30 Comparative Example The alloy powders containing 37wt% of Co, 18wt% of Cu, 19wt% of Ni, 23wt% of Fe and 3wt% of Ag are subjected to powder metallurgic process to obtain an anode, and before use, an oxide film is formed on the surface of the metal anode by pre-oxidization at 1 000 0 C to obtain an inert alloy anode A. 35 Test Example The inert alloy anodes 1-44 and A are each taken as an anode, graphite is taken as a cathode, the anode and the cathode are vertically inserted into an electrolytic cell provided with a corundum liner, and the distance between the anode and the cathode is 3cm. The anode has a current density of 1.OA/cm2 at 40 760 0 C, and is electrolyzed for up to 40 hours in an electrolyte having the components including 32wt% of sodium fluoride, 57wt% of aluminum fluoride, 3wt% of lithium fluoride, 4wt% of potassium fluoride and 4wt% of alumina, and the test results are shown in the Table below: Inert Alloy Anode Cell Voltage (V) Direct Current Purity of Product Consumption for Per Aluminum (%) Ton of Aluminum (kw-h) 1 3.10 10040 99.80 2 3.14 10170 99.81 3 3.22 10429 99.85 4 3.16 10235 99.80 5 3.10 10040 99.85 11/12 6 3.39 10979 99.82 7 3.15 10202 99.85 8 3.27 10591 99.85 9 3.18 10299 99.83 10 3.36 10882 99.81 11 3.28 10623 99.80 12 3.40 11000 99.82 13 3.32 10753 99.84 14 3.25 10526 99.82 15 3.12 10105 99.80 16 3.27 10591 99.81 17 3.35 10850 99.83 18 3.38 10947 99.80 19 3.16 10234 99.82 20 3.32 10753 99.83 21 3.10 10040 99.81 22 3.12 10105 99.82 23 3.11 10040 99.80 24 3.13 10159 99.81 25 3.21 10429 99.85 26 3.15 10236 99.80 27 3.11 10041 99.90 28 3.38 10979 99.82 29 3.14 10202 99.85 30 3.26 10591 99.91 31 3.17 10299 99.83 32 3.35 10879 99.81 33 3.27 10623 99.80 34 3.39 11000 99.82 35 3.33 10753 99.84 36 3.25 10526 99.82 37 3.12 10105 99.80 38 3.27 10591 99.81 39 3.35 10850 99.83 40 3.38 10945 99.80 41 3.16 10234 99.82 42 3.32 10753 99.83 43 3.10 10040 99.81 44 3.12 10110 99.82 A 4.48 14510 98.35 It can be seen from the test results of the aforementioned embodiments and the comparative example that in the process of aluminum electrolysis, the inert alloy anode in the present invention has a cell voltage much lower than that of the alloy anode in the comparative example, consequently, using the inert alloy anode in the present invention can reduce the power consumption in an aluminum electrolysis 5 process remarkably, which further reduces energy waste and lower cost. Meanwhile, the inert alloy anode in the present invention can be used for producing aluminum products which meet the high-purity standard, i.e. the purity of these aluminum products can be over 99.8, which meets the national primary aluminum standard.

12/12 Detailed description has been made to the specific contents of the present invention in the aforementioned embodiments, and it should be understood by those skilled in this art that modifications and detail variations in any form based upon the present invention pertain to the scope that the present invention seeks to protect. 5

Claims

1. An inert alloy anode for aluminum electrolysis, containing: Fe and Cu as primary components; 5 characterized in that the inert alloy anode further contains Sn.

2. The inert alloy anode according to claim 1, characterized in that the mass ratio of Fe to Cu to Sn is (23-40): (36-60): (0.2-5) or (40.01-80): (0.01-35.9): (0.01-0.19).

3. The inert alloy anode according to claim 1 or 2, characterized in that the inert alloy anode further 10 contains Ni.

4. The inert alloy anode according to claim 3, characterized in that the mass ratio of Fe to Cu to Ni to Sn is (23-40): (36-60): (14-28): (0.2-5) or (40.01-80): (0.01-35.9): (28.1-70): (0.01-0.19).

5. The inert alloy anode according to claim 3, being composed of Fe, Cu, Ni and Sn, wherein the content of Fe is 23-40wt%, the content of Cu is 36-60wt%, the content of Ni is 14-28wt% and the content of Sn is 15 0.2-5wt%, or the content of Fe is 40.01-71.88wt%, the content of Cu is 0.01 -31.88wt%, the content of Ni is 28.1-59.97wt% and the content of Sn is 0.01 -0.19wt%.

6. The inert alloy anode according to any of claims 1-5, further containing Al.

7. The inert alloy anode according to claim 6, being composed of Fe, Cu, Ni, Sn and Al, wherein the content of Fe is 23-40wt%, the content of Cu is 36-60wt%, the content of Ni is 14-28wt%, the content of 20 Al is more than zero and less than or equal to 4wt% and the content of Sn is 0.2-5wt%, or the content of Fe is 40.01-71.88wt%, the content of Cu is 0.01 -31.88wt%, the content of Ni is 28.1-59.97wt%, the content of Al is more than zero and less than or equal to 4wt% and the content of Sn is 0.01 -0.19wt%.

8. The inert alloy anode according to any of claims 1-7, further containing Y.

9. The inert alloy anode according to claim 8, being composed of Fe, Cu, Ni, Sn, Al and Y, wherein the 25 content of Fe is 23-40wt%, the content of Cu is 36-60wt%, the content of Ni is 14-28wt%, the content of Al is more than zero and less than or equal to 4wt%, the content of Y is more than zero and less than or equal to 2wt% and the content of Sn is 0.2-5wt%, or the content of Fe is 40.01-71.88wt%, the content of Cu is 0.01-31.88wt%, the content of Ni is 28.1 -59.97wt%, the content of Al is more than zero and less than or equal to 4wt%, the content of Y is more than zero and less than or equal to 2wt% and the content 30 of Sn is 0.01-0.19wt%.

10. A preparing method of the inert alloy anode according to any of claims 1-9, comprising the following steps: melting and uniformly mixing the metals Fe, Cu and Sn, and then rapidly casting and cooling the mixture to obtain the inert alloy anode; 35 or, melting the metals Fe, Cu and Sn at first, then adding and melting the metal Al or Y, and uniformly mixing, or adding and melting the metal Al at first and then adding and melting the metal Y, uniformly mixing, and rapidly casting and cooling the mixture to obtain the inert alloy anode; or, melting and mixing the metals Fe, Cu, Ni and Sn and then casting the mixture to obtain the inert alloy anode; 40 or, melting the metals Fe, Cu, Ni and Sn at first, then adding and melting the metal Al or Y, and uniformly mixing, or adding and melting the metal Al at first, then adding and melting the metal Y, uniformly mixing, and casting the mixture to obtain the inert alloy anode.