An inert electrode and a method for producing the same

Abstract

The application discloses an inert electrode and a preparation method thereof, and belongs to the technical field of inert electrodes. The inert electrode comprises a ceramic base body and a metal phase connected with the ceramic base body. The ceramic base body has a porosity of greater than or equal to 85%. The ceramic base body comprises zirconium and boron elements. The ceramic base body is provided with a plurality of channels, and the channels of the ceramic base body are filled with the metal phase. The inert electrode is not separated through a 65KA electrolytic cell hanging test. The resistance of the inert electrode is less than or equal to 1800 ohms. The inert electrode and the preparation method thereof can realize firm connection between a zirconium boride electrode and an anode guide rod, and do not increase the corrosion rate of the inert electrode.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrode preparation, in particular to the field of a preparation method of an inert electrode for electrolytic aluminum. BACKGROUND

[0002] The electrolytic aluminum industry is a high energy consumption and high emission industry, and energy saving and environmental protection has become the only way for the development of aluminum electrolysis technology.

[0003] At present, the anode material used on a large scale is carbon anode, which has good conductivity, low electrode density, light weight and other advantages, but has the problems of short service life (replaced once every 22-27 days), environmental pollution (release of a large amount of CO2 and CF4 greenhouse gases), large power consumption; for the production of one ton of electrolytic aluminum, the consumption of carbon anode is 450-550 kg, which accounts for 15-20% of the production cost of aluminum electrolysis, and about 1000 m 3 of pollution gas is discharged;

[0004] Developing new type of inert electrode material with high efficiency and energy saving is an urgent task in the electrolytic aluminum industry; zirconium boride is a hexagonal crystal, and its quasi-metallic structure determines that zirconium diboride has good conductivity and migration, has high melting point, high conductivity, corrosion resistance, melting point is 3245℃, resistivity is 1.5× 10 -5 Ω·m at room temperature, resistivity is 5.7×10 -5 Ω·m at 1000℃, resistant to aluminum, calcium, magnesium, silicon, lead and tin corrosion; compared with carbon and alloy anode, zirconium boride-based ceramic electrode is more resistant to high temperature, oxidation and electrolyte solution corrosion; compared with oxide electrode, zirconium boride ceramic has high conductivity and high thermal conductivity, therefore, it is considered as one of the ideal inert electrode materials; but the problem of zirconium boride ceramic is high density, the weight of zirconium boride electrode with the same volume is large, and when the zirconium boride electrode is connected with the anode guide rod, the problem of separation from the anode guide rod exists due to the large weight.

[0005] How to realize the normal connection of zirconium boride electrode with the anode guide rod, avoid the problem of separation from the anode guide rod due to the large weight of zirconium boride electrode, and at the same time avoid the problem of increased corrosion degree of zirconium boride electrode, has become a difficult problem in the field. SUMMARY

[0006] The application aims at how to realize firm connection of zirconium boride electrode and anode guide rod, avoid falling problem, and avoid corrosion problem of zirconium boride electrode in electrolyte solution, provides an inert electrode and its method; the ceramic matrix has porosity of 85%; the ceramic matrix is provided with a plurality of channels, and the channels of the ceramic matrix are filled with metal phase; the inert electrode is not separated in 65KA electrolytic cell mounting test, and its preparation method is provided to realize firm connection of zirconium boride electrode and anode guide rod, and effectively improve the corrosion resistance of zirconium boride electrode in electrolyte solution.

[0007] To achieve the above-mentioned purpose, according to one aspect of the application, an inert electrode is provided, which comprises a ceramic matrix and a metal phase connected with the ceramic matrix; the ceramic matrix has porosity of 85%; the ceramic matrix comprises zirconium and boron elements; the ceramic matrix is provided with a plurality of channels, and the channels are filled with metal phase; the inert electrode is not separated in 65KA electrolytic cell mounting test; the resistance of the inert electrode is less than or equal to 1800 ohms; the density of the ceramic matrix is 2-5 g / cm 3 .

[0008] Compared with the prior art, the inert electrode has the advantages that the ceramic matrix has porosity of 85%, the density of the inert electrode is reduced, the weight of the inert electrode is not high under the same volume, the problem of falling of the inert electrode from the anode guide rod is avoided when the inert electrode is connected with the anode guide rod, and the inert electrode cannot be normally used.

[0009] The ceramic matrix comprises zirconium and boron elements, the corrosion of electrolyte solution to the electrode during working of the inert electrode is greatly reduced, and the service life is greatly improved; compared with the carbon anode, the service life of the inert electrode is improved, and environmental pollution caused by a large amount of CO2 and CF4 greenhouse gases is avoided;

[0010] The ceramic matrix is provided with a plurality of channels, so that different temperature treatment can be carried out inside and outside the ceramic matrix during preparation of the ceramic matrix, the ceramic matrix has high porosity and dense surface at the same time, the weight is reduced, the problem of falling of the inert electrode from the anode guide rod is avoided, and the channels are filled with metal phase.

[0011] The channels are filled with metal phase, which is conducive to firm connection of the ceramic matrix and the anode guide rod, reduces the resistance of the inert electrode, fills the pores on the surface of the channels of the ceramic matrix, avoids penetration of electrolyte solution into the pores inside the ceramic matrix during working of the inert electrode, and improves corrosion resistance of the inert electrode to electrolyte solution.

[0012] The inert electrode passes the electrolytic cell hanging test of 65KA, the inert electrode does not fall off, and thus the inert electrode does not fall off from the anode guide rod during use.

[0013] Further, the ceramic matrix further comprises hafnium, tantalum and carbon elements.

[0014] And / or

[0015] The metal phase comprises aluminum and / or copper elements.

[0016] The beneficial effects of the above further technical solutions are that, by the ceramic matrix further comprising hafnium, tantalum and carbon elements, the sintering temperature during the preparation of the ceramic matrix is reduced, and the oxidation temperature of the ceramic matrix in the inert electrode during use is improved, so that the inert electrode is prevented from being oxidized and decomposed due to the temperature reaching 800-900℃ during use, and the service life of the inert electrode is improved.

[0017] Further, the ceramic matrix is sequentially provided with a dense layer and a loose layer from the outer surface to the inside; the inner pore diameter of the dense layer is smaller than that of the loose layer; and the closed pore rate of the inner pores of the dense layer is greater than that of the inner pores of the loose layer.

[0018] The beneficial effects of the above further technical solutions are that, by the inner pore diameter of the dense layer being smaller than that of the loose layer, and the closed pore rate of the inner pores of the dense layer being greater than that of the inner pores of the loose layer, the density of the ceramic matrix is small, and the problem of the electrolyte solution entering a large number of pores in the ceramic matrix during use of the inert electrode is avoided, so that the corrosion rate of the electrolyte solution to the inert electrode during use of the inert electrode is improved.

[0019] According to another aspect of the present application, a preparation method of an inert electrode is provided, comprising the following steps: preparing a ceramic slurry; injecting the ceramic slurry into a first mold, freezing the ceramic slurry in the first mold to form a primary ceramic blank, and then drying the primary ceramic blank to obtain a ceramic blank; using differential temperature drying on the outer surface and the inside of the primary ceramic blank; and the primary ceramic blank and the ceramic blank being provided with a plurality of channels.

[0020] The ceramic blank is degreased;

[0021] The degreased ceramic blank is sintered to obtain a ceramic matrix provided with a plurality of channels; and a molten metal liquid is connected to the ceramic matrix.

[0022] Preferably, after the ceramic blank is sintered and before being connected to the molten metal liquid, the ceramic blank is placed in an oxidizing furnace for oxidation treatment.

[0023] Compared with the prior art, the beneficial effects of the technical scheme of the present application are that: by injecting the ceramic slurry into the first mold, the obtained primary ceramic body is provided with a plurality of channels; by freezing the ceramic slurry in the first mold to form a primary ceramic body, and then drying the primary ceramic body, the ceramic body is prepared while a large number of pores and / or cracks are formed in the ceramic body, which is beneficial to realize a high porosity of the ceramic matrix and a porosity of the ceramic matrix of ≥ 85 %.

[0024] By using differential temperature drying on the outer surface and the interior of the primary ceramic body, while a large number of pores and / or cracks are formed in the ceramic body, the ceramic matrix is sequentially provided with a dense layer and a loose layer from the outer surface to the interior, the dense layer has a high density, a small pore size, and a higher closed pore rate of the internal pores than the closed pore rate of the internal pores of the loose layer; thereby avoiding the problem of increasing the corrosion rate of the electrolyte solution on the inert electrode during the use of the inert electrode.

[0025] By performing glue removal on the ceramic body and sintering the ceramic body after glue removal, that is, by controlling the glue removal and sintering in stages, the ceramic matrix is sequentially provided with a dense layer and a loose layer from the outer surface to the interior, and the ceramic matrix has a high internal porosity and a dense outer surface.

[0026] By connecting the molten metal liquid with the ceramic matrix, the channels of the ceramic matrix are filled with a metal phase.

[0027] By preferably placing the sintered ceramic body into an oxidizing furnace for oxidation treatment before connecting with the molten metal liquid, the corrosion rate of the electrolyte solution on the inert electrode during the use of the inert electrode is further reduced.

[0028] Further, the preparation process of the ceramic slurry is that: ceramic powder, resin, dispersant, and solvent are mixed and ground to obtain a ceramic slurry; the mass ratio of the ceramic powder, solvent, resin, and dispersant is (7-9):(3-1):(0.25-0.1):(0.15-0.05).

[0029] The solvent is one or more of deionized water, anhydrous ethanol, and acetone.

[0030] The added resin is phenolic resin and / or furan resin, and the carbon residue rate of the resin is > 30 %; the dispersant is polyacrylammonium and / or polyethylene glycol.

[0031] The beneficial effects of the further technical solutions are that the mass ratio of the ceramic powder, the solvent, the resin, and the dispersing agent is (7-9):(3-1):(0.1-0.25):(0.05-0.15), which is conducive to achieving a high porosity of the ceramic green body and not significantly reducing the strength of the ceramic matrix.

[0032] The resin is phenolic resin and / or furan resin, and the carbon residue rate of the resin is greater than 30%, which is conducive to improving the strength of the dried green body and simultaneously serving as a sintering aid to promote sintering densification when the ceramic green body is sintered.

[0033] Further, the ceramic powder includes zirconium boride powder, hafnium carbide powder, tantalum carbide powder, silicon carbide powder, and boron carbide powder, and the mass ratio of the zirconium boride powder, the hafnium carbide powder, the tantalum carbide powder, the silicon carbide powder, and the boron carbide powder is (6-9):(2-0.5):(1-0.5):(3-1):(1-0.5). Preferably, the zirconium boride powder, the hafnium carbide powder, and the tantalum carbide powder are mixed to obtain zirconium boride-based high-entropy powder, and then the zirconium boride-based high-entropy powder is mixed with the silicon carbide powder and the boron carbide powder.

[0034] The beneficial effects of the further technical solutions are that the ceramic powder includes zirconium boride powder, hafnium carbide powder, tantalum carbide powder, silicon carbide powder, and boron carbide powder, and the ceramic powder includes zirconium boride powder, hafnium carbide powder, and tantalum carbide powder, which is conducive to achieving high-entropy effect of the ceramic matrix, improving the material migration energy barrier, and achieving high-temperature stability of the ceramic matrix during use. Meanwhile, the rapid growth of ZrB2 grains during high-temperature sintering can be inhibited, the mechanical properties of the ceramic matrix can be improved, and the strength of the ceramic matrix is not significantly reduced under high porosity.

[0035] The ceramic particles include silicon carbide powder and boron carbide powder, which is conducive to reducing the sintering temperature of the ceramic matrix.

[0036] Further, the first mold includes an upper mold and a lower mold, and the upper mold is provided with a plurality of pore-forming rods, and the primary ceramic green body is provided with a plurality of channels through the pore-forming rods.

[0037] Further, the specific process of preparing the ceramic green body is freezing the first mold into which the ceramic slurry is injected, the freezing temperature of the cold source is -60 to -30℃, and the freezing time is 10 to 72 hours, and the ceramic slurry is frozen to obtain a primary ceramic green body provided with a plurality of channels.

[0038] The first temperature control device is arranged in the plurality of channels of the primary ceramic green body, and the second temperature control device is arranged in the space for placing the primary ceramic green body, and the primary ceramic green body is dried by controlling different temperatures through the first temperature control device and the second temperature control device.

[0039] The first temperature control device controls the temperature to be-10~0℃; the second temperature control device controls the temperature to be-60~-30℃.

[0040] The space for placing the primary ceramic body has a pressure of 10~30Pa.

[0041] Preferably, the drying time of the primary ceramic body is 20~72h; and preferably, a gap is left between the first temperature control device and the channels of the primary ceramic body.

[0042] The beneficial effects of the above further technical solutions are that, by controlling the temperature of the first temperature control device to be-10~0℃ and the temperature of the second temperature control device to be-60~-30℃, the internal temperature of the primary ceramic body rises at a high rate and to a high temperature, while the external temperature of the primary ceramic body rises at a low rate and to a low temperature when the primary ceramic body is dried, so that large pores and / or cracks are generated in the internal ceramic body, the porosity of the obtained ceramic body is high, and the external surface of the obtained ceramic body has small pores, low porosity and a dense surface.

[0043] By leaving a gap between the first temperature control device and the channels of the primary ceramic body, the volatiles in the internal ceramic body are discharged from the gap, avoiding the problem of increased surface porosity of the ceramic body caused by the discharge of internal volatiles from the surface, so that the surface of the ceramic body is dense.

[0044] Further, the specific process of degreasing the ceramic body is that, the temperature of the ceramic body before degreasing is room temperature, and the degreasing is performed under negative pressure; a third temperature control device is arranged in the channels of the ceramic body, and a fourth temperature control device is arranged in the space for placing the ceramic body, and the ceramic body is degreased by controlling different temperatures through the third and fourth temperature control devices.

[0045] The third temperature control device controls the highest degreasing temperature to be 450~500℃, and the temperature rises from room temperature to 450~500℃ at a rate of 6~8℃ / min; the fourth temperature control device controls the highest degreasing temperature to be 350~400℃, and the temperature rises from room temperature to 350~400℃ at a rate of 1~2℃ / min.

[0046] The negative pressure is 10 3 ~10 4 Pa.

[0047] Preferably, a gap is left between the third temperature control device and the channels of the ceramic body.

[0048] The beneficial effects of the further technical solutions are that the third temperature control device controls the highest glue discharging temperature to be 450-500 DEG C, the temperature rising rate from room temperature to 450-500 DEG C is 6-8 DEG C / min; the fourth temperature control device controls the highest glue discharging temperature to be 350-400 DEG C, the temperature rising rate from room temperature to 350-400 DEG C is 1-2 DEG C / min, which is beneficial to realize the fast temperature rising rate in the ceramic body and the slow temperature rising rate on the surface of the ceramic body, so as to realize the large internal void of the ceramic body and the small and dense external surface.

[0049] Further, the specific process of sintering the ceramic body after glue discharging is that the ceramic body is heated and sintered under the inert gas atmosphere, and then is subjected to segmented cooling after heating.

[0050] The heating and sintering temperature is 1900-2100 DEG C, and the temperature rising rate is 5-10 DEG C / min.

[0051] The holding time at 1900-2100 DEG C is 30-60 DEG C / min.

[0052] The segmented cooling process is that the first segment cooling is from 1900-2100 DEG C to 1000 DEG C at a rate of 1-5 DEG C / min.

[0053] The second segment cooling is from 1000 DEG C to room temperature at a rate of 10 DEG C / min.

[0054] Preferably, when the ceramic body is sintered, the space where the ceramic body is placed is provided with a fifth temperature control device and a sixth temperature control device; the fifth temperature control device is arranged at the opposite position of the channel of the ceramic body; and the sixth temperature control device is arranged away from the channel position of the ceramic body.

[0055] The fifth temperature control device controls the highest sintering temperature to be 1950-2100 DEG C, and the sixth temperature control device controls the highest sintering temperature to be 1900-1950 DEG C.

[0056] The beneficial effects of the further technical solutions are that by arranging the fifth temperature control device at the opposite position of the channel of the ceramic body and arranging the sixth temperature control device away from the channel position of the ceramic body, the internal and external temperature difference of the ceramic body can be heated and sintered; by controlling the highest sintering temperature of the fifth temperature control device to be 1950-2100 DEG C and the highest sintering temperature of the sixth temperature control device to be 1900-1950 DEG C, the ceramic body can be sintered to obtain the ceramic substrate, and the surface grains of the ceramic substrate are small and the surface is dense.

[0057] Further, the connecting the molten metal liquid with the ceramic matrix specifically comprises: infiltrating the molten metal liquid into the channels of the ceramic matrix; and the temperature of the molten metal liquid is 1000-1500 DEG C.

[0058] The beneficial effects of the above further technical solutions are that the channels of the ceramic matrix are filled with the metal phase, and the metal phase infiltrates into the surface pores of the channels of the ceramic matrix, which is further conducive to realizing the close connection between the ceramic matrix and the metal phase, and protecting the surface of the channels of the ceramic matrix, thereby avoiding the increase of the corrosion rate of the inert electrode in the internal electrolyte solution through the channels during use.

[0059] The ceramic matrix is connected with the anode rod through the metal phase, thereby facilitating the realization of high connection strength between the inert electrode and the anode rod. DETAILED DESCRIPTION

[0060] In order to better understand the technical solutions of the present application, the following specific embodiments are further described.

[0061] Embodiment 1:

[0062] One aspect of the embodiment provides an inert electrode, comprising a ceramic matrix and a metal phase connected with the ceramic matrix; the ceramic matrix has a porosity of ≥85%; the ceramic matrix comprises zirconium, boron, hafnium, tantalum and carbon elements; the ceramic matrix is provided with a plurality of channels, and the channels are filled with the metal phase; the inert electrode is subjected to a 65KA electrolytic cell hanging test, and the inert electrode does not fall off; the resistance of the inert electrode is 1750 ohms; and the density of the ceramic matrix is 3g / cm 3 .

[0063] The metal phase comprises aluminum and copper elements.

[0064] The ceramic matrix is sequentially provided with a dense layer, a loose

[0065] layer and an inner layer from the outer surface to the inner part; the inner pore size of the dense layer is smaller than that of the loose layer; and the closed pore rate of the inner pores of the dense layer is greater than that of the loose layer.

[0066] Another aspect of the embodiment provides a preparation method of an inert electrode, comprising the following steps: preparing a ceramic slurry;

[0067] The preparation process of the ceramic slurry comprises: mixing and grinding ceramic powder, resin, dispersant and solvent to obtain the ceramic slurry; the mass ratio of the ceramic powder, the solvent, the resin and the dispersant is 8:2:0.18:0.1; and the solvent is deionized water.

[0068] The additive resin is phenolic resin, and the carbon residue rate of the resin is >30%; the dispersing agent is ammonium polyacrylate;

[0069] The ceramic powder includes zirconium boride powder, hafnium carbide powder, tantalum carbide powder, silicon carbide powder, and boron carbide powder; the mass ratio of the zirconium boride powder, hafnium carbide powder, tantalum carbide powder, silicon carbide powder, and boron carbide powder is 7.5:1.3:0.8:2:0.8; the zirconium boride powder, hafnium carbide powder, and tantalum carbide powder are mixed to obtain zirconium boride-based high-entropy powder, and then the zirconium boride-based high-entropy powder is mixed with the silicon carbide powder and the boron carbide powder;

[0070] The ceramic slurry is injected into the first mold, and the ceramic slurry in the first mold is solidified by freezing to obtain a primary ceramic body, and then the primary ceramic body is dried to obtain a ceramic body; the outer surface and the inner part of the primary ceramic body are dried by differential temperature drying; the primary ceramic body and the ceramic body are provided with a plurality of channels;

[0071] The first mold includes an upper mold and a lower mold; the upper mold is provided with a plurality of pore-forming rods, and the primary ceramic body is provided with a plurality of channels through the pore-forming rods.

[0072] The specific process of preparing the ceramic body is that the first mold into which the ceramic slurry is injected is frozen, the temperature of the cold source for freezing is-45℃, and the freezing time is 41h; the ceramic slurry is frozen to obtain a primary ceramic body provided with a plurality of channels;

[0073] The first temperature control device is arranged in the plurality of channels of the primary ceramic body, and the second temperature control device is arranged in the space for placing the primary ceramic body; the primary ceramic body is dried by controlling different temperatures through the first temperature control device and the second temperature control device;

[0074] The temperature controlled by the first temperature control device is-9℃, the temperature controlled by the second temperature control device is-40℃, the air pressure of the space for placing the primary ceramic body is 20Pa, and the drying time of the primary ceramic body is 30h;

[0075] The first temperature control device and the channels of the primary ceramic body are left with a gap;

[0076] By drying the outer surface and the inner part of the primary ceramic body by differential temperature, a large number of pores and / or cracks are formed in the inner part of the ceramic body, at the same time, the ceramic matrix is provided with a dense layer and a loose layer from the outer surface to the inner part in turn, the dense layer has high density, small pore size, and the closure rate of the pores in the inner part of the dense layer is higher than that of the loose layer; thereby avoiding the problem of increasing the corrosion rate of the electrolyte solution to the inert electrode during the use of the inert electrode;

[0077] The ceramic body is degreased;

[0078] The specific process of degreasing of the ceramic body is that the temperature of the ceramic body before degreasing is room temperature, and the degreasing is carried out under negative pressure; the third temperature control device is arranged in the channels of the ceramic body, and the fourth temperature control device is arranged in the space where the ceramic body is placed; the ceramic body is degreased by controlling different temperatures through the third temperature control device and the fourth temperature control device;

[0079] The third temperature control device controls the highest degreasing temperature to be 480℃, and the temperature rising rate from room temperature to 480℃ is 7℃ / min; the fourth temperature control device controls the highest degreasing temperature to be 380℃, and the temperature rising rate from room temperature to 380℃ is 1.5℃ / min; the negative pressure is 10 3 ~10 4 Pa;

[0080] The third temperature control device and the channels of the ceramic body have a gap therebetween;

[0081] The ceramic body after degreasing is sintered to obtain a ceramic matrix provided with channels; the specific process is that the ceramic body is heated and sintered under an inert gas atmosphere, and the inert gas is argon; and after heating, the ceramic body is subjected to staged cooling;

[0082] The heating and sintering temperature is 1900-2100℃, and the temperature rising rate is 5-10℃ / min.

[0083] The holding time at 1900-2100℃ is 50℃ / min; when the ceramic body is sintered, the space where the ceramic body is placed is provided with a fifth temperature control device and a sixth temperature control device; the fifth temperature control device is arranged at a position opposite to the channels of the ceramic body; and the sixth temperature control device is arranged at a position away from the channels of the ceramic body;

[0084] The fifth temperature control device controls the highest sintering temperature to be 2050℃, and the sixth temperature control device controls the highest sintering temperature to be 1920℃;

[0085] The staged cooling process is that the first-stage cooling is from 1900-2100℃ to 1000℃ at a rate of 3℃ / min;

[0086] The second-stage cooling is from 1000℃ to room temperature at a rate of 10℃ / min;

[0087] Before the ceramic body after sintering is connected with a molten metal liquid, the ceramic body is placed in an oxidizing furnace for oxidation treatment;

[0088] The molten metal liquid is connected with the ceramic matrix, and the specific process is that the molten metal liquid is infiltrated into the channels of the ceramic matrix; and the temperature of the molten metal liquid is 1300℃.

[0089] Embodiment 2:

[0090] The same content as Embodiment 1 is not repeated, and the features different from Embodiment 1 are that:

[0091] The inert electrode resistance is 1700 ohms; the density of the ceramic matrix is 2.5 g / cm 3 .

[0092] The mass ratio of the ceramic powder, solvent, resin, and dispersant is 7.5:2.5:0.2:0.12; the solvent is anhydrous ethanol;

[0093] The added resin is furan resin, and the carbon residue rate of the resin is >35%; the dispersant is polyethylene glycol;

[0094] The mass ratio of the zirconium boride powder, hafnium carbide powder, tantalum carbide powder, silicon carbide powder, and boron carbide powder is 8:1.1:0.6:1.5:0.6;

[0095] The specific process of preparing the ceramic body is that the first mold into which the ceramic slurry is injected is frozen, the cold source temperature for freezing is-55℃, and the freezing time is 65 h. The ceramic slurry is frozen to obtain a primary ceramic body provided with a plurality of channels;

[0096] The temperature controlled by the first temperature control device is-5℃; the temperature controlled by the second temperature control device is-50℃; the space in which the primary ceramic body is placed has a gas pressure of 25 Pa; and the drying time of the primary ceramic body is 25 h;

[0097] The third temperature control device controls the highest glue discharge temperature to be 460℃, and the temperature rising rate from room temperature to 460℃ is 6.5℃ / min; the fourth temperature control device controls the highest glue discharge temperature to be 370℃; and the temperature rising rate from room temperature to 370℃ is 1.2℃ / min;

[0098] The ceramic body after glue discharge is sintered to obtain a ceramic matrix provided with a plurality of channels; the specific process is that the ceramic body is heated and sintered in an inert gas atmosphere, and then is subjected to stepwise cooling after heating;

[0099] The holding time at 1900-2100℃ is 55℃ / min;

[0100] When the ceramic body is sintered, the space in which the ceramic body is placed is provided with a fifth temperature control device and a sixth temperature control device; the fifth temperature control device is arranged at the opposite position of the channels of the ceramic body; and the sixth temperature control device is arranged at a position far away from the channels of the ceramic body;

[0101] The fifth temperature control device controls the highest sintering temperature to be 2000℃, and the sixth temperature control device controls the highest sintering temperature to be 1910℃;

[0102] The first-stage temperature reduction is from 1900-2100℃ to 1000℃ at a rate of 2.5℃ / min, and the second-stage temperature reduction is from 1000℃ to room temperature at a rate of 10℃ / min;

[0103] The molten metal liquid is infiltrated into the channels of the ceramic matrix, and the temperature of the molten metal liquid is 1200℃.

[0104] Embodiment 3:

[0105] The same content as Embodiment 1 is not repeated, and the features different from Embodiment 1 are that:

[0106] The inert electrode resistance is 1720Ω, and the density of the ceramic matrix is 2.8g / cm 3 .

[0107] The mass ratio of the ceramic powder, the solvent, the resin, and the dispersant is 8.5:1.5:0.12:0.07, and the solvent is acetone;

[0108] The added resin is phenolic resin and furan resin, and the dispersant is ammonium polyacrylate and polyethylene glycol;

[0109] The mass ratio of the zirconium boride powder, the hafnium carbide powder, the tantalum carbide powder, the silicon carbide powder, and the boron carbide powder is 7:1.6:0.9:2.5:0.9;

[0110] The specific process of preparing the ceramic body is that the first mold into which the ceramic slurry is injected is frozen, the temperature of the cold source for freezing is-40℃, and the freezing time is 20h, and the ceramic slurry is frozen to obtain a primary ceramic body provided with a plurality of channels;

[0111] The first temperature control device controls the temperature to be-3℃, and the second temperature control device controls the temperature to be-32℃;

[0112] The space in which the primary ceramic body is placed has a gas pressure of 15Pa, and the drying time of the primary ceramic body is 50h;

[0113] The third temperature control device controls the highest glue discharging temperature to be 490℃, and the temperature is raised from room temperature to 490℃ at a rate of 7.5℃ / min; and the fourth temperature control device controls the highest glue discharging temperature to be 390℃, and the temperature is raised from room temperature to 390℃ at a rate of 1.8℃ / min;

[0114] Sintering the ceramic body after the glue is removed to obtain a ceramic matrix provided with a plurality of channels; the specific process is to heat and sinter the ceramic body in an inert gas atmosphere, and then perform segmented cooling after heating;

[0115] The holding time is 35℃ / min at 1900-2100℃;

[0116] The space where the ceramic body is placed is provided with a fifth temperature control device and a sixth temperature control device when the ceramic body is sintered; the fifth temperature control device is arranged at the opposite position of the channel of the ceramic body; and the sixth temperature control device is arranged at the position far away from the channel of the ceramic body;

[0117] The highest sintering temperature controlled by the fifth temperature control device is 2000℃, and the highest sintering temperature controlled by the sixth temperature control device is 1930℃;

[0118] The first-stage cooling process is to reduce the temperature from 1900-2100℃ to 1000℃ at a rate of 4℃ / min;

[0119] The second-stage cooling process is to reduce the temperature from 1000℃ to room temperature at a rate of 10℃ / min;

[0120] The molten metal liquid is infiltrated into the channel of the ceramic matrix; the temperature of the molten metal liquid is 1400℃.

[0121] The above description is only the preferred embodiments of the present application and the explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by the combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features can be combined with the features disclosed in the present application (but not limited to) having similar functions.

Claims

1. An inert electrode, characterized in that, The ceramic matrix comprises zirconium and boron elements, and the metal phase is connected to the ceramic matrix; The ceramic matrix has a porosity of ≥85%; the ceramic matrix comprises zirconium and boron elements; The ceramic matrix is provided with a plurality of channels, and the channels of the ceramic matrix are filled with a metal phase; The inert electrode passes the 65KA electrolytic cell hanging test, and the inert electrode does not fall off; The resistance of the inert electrode is ≤1800Ω; During the preparation of the inert electrode, the outer surface and the inner part of the primary ceramic body are dried by differential temperature; the primary ceramic body and the ceramic body are provided with a plurality of channels; The first mold into which the ceramic slurry is injected is frozen, the temperature of the cold source for freezing is-60--30℃, and the freezing time is 10-72h. The ceramic slurry is frozen to obtain a primary ceramic body provided with a plurality of channels. A first temperature control device is arranged in the plurality of channels of the primary ceramic body, and a second temperature control device is arranged in the space for placing the primary ceramic body. The primary ceramic body is dried by controlling different temperatures through the first temperature control device and the second temperature control device. The temperature controlled by the first temperature control device is-10-0℃, and the temperature controlled by the second temperature control device is-60--30℃. The space for placing the primary ceramic body has a gas pressure of 10-30Pa. The specific process of degassing the ceramic body is that the temperature of the ceramic body before degassing is room temperature, and the degassing is carried out under negative pressure. A third temperature control device is arranged in the plurality of channels of the ceramic body, and a fourth temperature control device is arranged in the space for placing the ceramic body. The ceramic body is degassed by controlling different temperatures through the third temperature control device and the fourth temperature control device. The third temperature control device controls the highest degassing temperature to be 450-500℃, and the temperature rising rate from room temperature to 450-500℃ is 6-8℃ / min. The fourth temperature control device controls the highest degassing temperature to be 350-400℃, and the temperature rising rate from room temperature to 350-400℃ is 1-2℃ / min. The negative pressure is 10 3 -10 4 Pa.

2. The inert electrode according to claim 1, characterized in that The ceramic matrix further comprises hafnium, tantalum and carbon elements. And / or The metal phase comprises aluminum and / or copper elements.

3. The inert electrode of claim 1, wherein The ceramic matrix is sequentially provided with a dense layer and a loose layer from the outer surface to the inner part; the inner pore diameter of the dense layer is smaller than that of the loose layer; and the closed pore rate of the inner pores of the dense layer is greater than that of the inner pores of the loose layer.

4. A method of preparing an inert electrode, characterized by, The method comprises the following steps: Preparation of ceramic slurry; The ceramic slurry is injected into a first mold, and the ceramic slurry in the first mold is solidified and formed by freezing to obtain a primary ceramic body. Then, the primary ceramic body is dried to obtain a ceramic body. The outer surface and the inner part of the primary ceramic body are dried by differential temperature; the primary ceramic body and the ceramic body are provided with a plurality of channels; The ceramic body is degassed; The degassed ceramic body is sintered to obtain a ceramic matrix provided with a plurality of channels; The molten metal liquid is connected to the ceramic matrix.

5. The method of claim 4, wherein the ceramic membrane is prepared by a method comprising: The preparation process of the ceramic slurry is that ceramic powder, resin, dispersant and solvent are mixed and ground to obtain the ceramic slurry; The mass ratio of the ceramic powder, solvent, resin, dispersant is (7-9):(3-1):(0.25-0.1):(0.15-0.05); The solvent is one or more of deionized water, anhydrous ethanol, acetone; The added resin is phenolic resin and / or furan resin, and the carbon residue rate of the resin is >30%; The dispersant is polyacrylamide and / or polyethylene glycol.

6. The method of claim 5, wherein the ceramic membrane is prepared by a method comprising: The ceramic powder includes zirconium boride powder, hafnium carbide powder, tantalum carbide powder, silicon carbide powder, and boron carbide powder; the mass ratio of the zirconium boride powder, hafnium carbide powder, tantalum carbide powder, silicon carbide powder, and boron carbide powder is (6-9):(2-0.5):(1-0.5):(3-1):(1-0.5).

7. The method of claim 4, wherein the ceramic membrane is prepared by a process comprising: The first mold includes an upper mold and a lower mold; the upper mold is provided with a plurality of pore-forming rods, and the primary ceramic body is provided with a plurality of channels through the pore-forming rods.

8. The method of claim 7, wherein the ceramic membrane is prepared by a method comprising: The specific process for preparing the ceramic body is freezing the first mold into which the ceramic slurry is injected, the freezing source temperature is -60--30℃, and the freezing time is 10-72h; the ceramic slurry is frozen to obtain a primary ceramic body provided with a plurality of channels; A first temperature control device is arranged in the plurality of channels of the primary ceramic body, and a second temperature control device is arranged in the space for placing the primary ceramic body; the primary ceramic body is dried by controlling different temperatures through the first temperature control device and the second temperature control device; The first temperature control device controls the temperature to be -10-0℃; and the second temperature control device controls the temperature to be -60--30℃; The space for placing the primary ceramic body has an air pressure of 10-30Pa.

9. The method of claim 4, wherein the ceramic membrane is prepared by a process comprising: The specific process for degassing the ceramic body is that the temperature of the ceramic body before degassing is room temperature, and the degassing is performed under negative pressure; a third temperature control device is arranged in the plurality of channels of the ceramic body, and a fourth temperature control device is arranged in the space for placing the ceramic body; the ceramic body is degassed by controlling different temperatures through the third temperature control device and the fourth temperature control device; The third temperature control device controls the highest degassing temperature to be 450-500℃, and the temperature rising rate from room temperature to 450-500℃ is 6-8℃ / min; the fourth temperature control device controls the highest degassing temperature to be 350-400℃, and the temperature rising rate from room temperature to 350-400℃ is 1-2℃ / min; The negative pressure is 10 3 -10 4 Pa.

10. The method for preparing a ceramic membrane according to claim 4, characterized in that, The specific process for sintering the degassed ceramic body is that the ceramic body is heated and sintered under an inert gas atmosphere, and then is subjected to staged cooling after heating; The heating and sintering temperature is 1900-2100℃, and the temperature rising rate is 5-10℃ / min. The holding time at 1900-2100℃ is 30-60℃ / min; In the staged cooling process, the first stage cooling rate from 1900-2100℃ to 1000℃ is 1-5℃ / min; The second stage cooling rate from 1000℃ to room temperature is 10℃ / min. And / or The specific process for connecting the molten metal liquid with the ceramic matrix is that the molten metal liquid is infiltrated into the channels of the ceramic matrix; the temperature of the molten metal liquid is 1000℃-1500℃.