Preparation method of resin prebaked anode and resin prebaked anode

Abstract

The invention belongs to the field of preparation of prebaked anodes for aluminum, and discloses a preparation method of a resin prebaked anode and the resin prebaked anode. The method comprises the following steps: preparing a resin anode green body, carrying out flash burning treatment on the surface of the resin anode green body, drying and curing, preheating a dried and cured resin anode preform, and conveying the resin anode preform to a roasting furnace for roasting to obtain the resin prebaked anode. The problems of cracks and slag falling caused by insufficient binding force of phenolic resin in the temperature range of 60-80 DEG C are effectively solved through the flash firing treatment process, and the integrity and stability of the product are improved.

Description

Technical Field

[0001] The present application belongs to the field of preparation of prebaked anodes for aluminum, and specifically relates to a preparation method of a resin prebaked anode and a resin prebaked anode. Background Art

[0002] Coal tar pitch has long held a crucial position as a core binder in the prebaked anode production industry. However, the traditional process for baking prebaked anodes using coal tar pitch as a binder presents numerous drawbacks that are difficult to ignore. During baking, the coal tar pitch undergoes a significant softening phase, which significantly prolongs the baking cycle, typically taking approximately one month. This lengthy baking cycle not only occupies production equipment and site resources, resulting in low overall production efficiency, but also significantly increases energy consumption and production costs.

[0003] Phenolic resin is considered one of the ideal candidate materials to replace coal tar due to its outstanding advantages such as low pollution emissions. From a theoretical perspective, phenolic resin has great potential for rapid roasting, and is expected to significantly shorten the roasting time to five days, which is of great significance for improving production efficiency and reducing production costs. However, the unique physical and chemical properties of phenolic resin also bring a series of new technical difficulties. In the critical stage of green body curing, phenolic resin exhibits extremely low viscosity in the temperature range of 60 to 80°C. This characteristic makes its bonding strength to the carbon block seriously insufficient. In this process, the carbon block is prone to quality problems such as cracking and slagging. These problems not only affect the appearance quality of the pre-baked anode, but also have a serious negative impact on its internal performance, greatly reducing the market competitiveness of the product.

[0004] Therefore, based on the current pre-baked anode baking technology of phenolic resin, developing a new pre-baked anode baking method that can not only effectively improve the bonding properties of phenolic resin, but also significantly improve production efficiency and reduce environmental pollution has become an urgent need for current industry technological innovation. Summary of the Invention

[0005] Traditional phenolic resin prebaked anode production processes suffer from insufficient phenolic resin bonding, low production efficiency, and severe pollution. This application provides a method for preparing a resin prebaked anode, and the resulting resin prebaked anode. This method utilizes a flash curing process to improve the bonding properties of the phenolic resin.

[0006] In one aspect of the present application, a method for preparing a resin prebaked anode is provided, comprising:

[0007] preparing a resin anode green body;

[0008] Flash-burning the surface of the resin anode green body to form a hard shell structure on the surface of the resin anode green body to obtain a resin anode preform;

[0009] drying and curing the resin anode preform;

[0010] The dried and solidified resin anode preform is baked.

[0011] In one embodiment, the raw materials of the resin anode green body include a binder and an aggregate.

[0012] In one embodiment, the weight ratio of the binder in the raw material is 5-40%, preferably 5-20%, more preferably 5-18%; the weight ratio of the aggregate in the raw material is 60-95%, preferably 82-95%.

[0013] In one embodiment, the aggregate is selected from petroleum coke, or a mixture of petroleum coke and carbon materials such as graphite chips and carbon nanotubes; the petroleum coke accounts for more than 50 wt% of the mixture, preferably more than 80 wt%.

[0014] In one embodiment, the aggregate may also contain spent prebaked anodes.

[0015] In one embodiment, the binder contains phenolic resin and coal tar.

[0016] In one embodiment, the coal tar pitch accounts for less than 5 wt %, preferably less than 2 wt %, and more preferably less than 1 wt % of the raw material.

[0017] In one embodiment, the binder is a phenolic resin.

[0018] In one embodiment, the phenolic resin may be a phenolic resin commonly used in the art, such as one or more of biomass-modified phenolic resin, asphalt-modified phenolic resin, coal tar-modified phenolic resin, alkylphenol-modified phenolic resin and rubber-modified phenolic resin.

[0019] In one embodiment, the temperature of the flash treatment is 300-500°C.

[0020] In one embodiment, the flash treatment is performed 2 to 3 times.

[0021] In one embodiment, when the flash treatment is performed multiple times, the time interval between two adjacent flash treatments is 10 to 30 minutes.

[0022] In one embodiment, the thickness of the hard shell layer on the surface of the resin anode preform is 1 to 3 mm.

[0023] In one embodiment, the hardness of the hard shell layer on the surface of the resin anode preform is 20 to 37 MPa, more preferably 28 to 32 MPa.

[0024] In one embodiment, drying and curing the resin anode preform comprises:

[0025] placing the resin anode preform in the cover;

[0026] The resin anode preform covered with the cover body is heated.

[0027] In one embodiment, a contact interface is constructed between the cover and the resin anode preform, and the interface is characterized by a continuous fitting morphology without macroscopic gaps.

[0028] In one embodiment, a contact interface is constructed between the cover and the resin anode preform, and the interface is characterized by a discontinuous fitting form with a macro gap, and the macro gap is filled with high temperature resistant particles at the contact interface, thereby making it exhibit a continuous fitting form.

[0029] In one embodiment, the high temperature resistant particulate matter is, for example, metallurgical coke.

[0030] In one embodiment, the cover is made of a material selected from silicon carbide and stainless steel, preferably silicon carbide.

[0031] In one embodiment, the temperature set for the heating operation is 140-220°C.

[0032] In one embodiment, the heating operation time is 10 to 24 hours.

[0033] In one embodiment, drying and curing the resin anode preform comprises:

[0034] The resin anode preform is covered with a filler carrying heat energy, and the filler provides the resin anode preform with heat energy required for drying by heat conduction. In addition, the filler also has the effect of preventing the resin anode preform from being oxidized.

[0035] In one embodiment, the resin anode preform is placed in a sagger for drying and curing.

[0036] In one embodiment, the filler is selected from metallurgical coke, river sand, etc.

[0037] In one embodiment, the temperature corresponding to the thermal energy of the filler is 180-220°C.

[0038] In one embodiment, before the calcination, the method further comprises: preheating the dried and solidified resin anode preform, wherein the preheating temperature is 300-800°C.

[0039] In one embodiment, the baking of the dried and solidified resin anode preform includes a firing stage and a cooling stage.

[0040] In one embodiment, the maximum temperature during the firing stage is at least 1150°C, preferably between 1150°C and 1250°C. In this embodiment, to ensure excellent performance of the resulting prebaked anode, the firing temperature is not recommended to be lower than 1150°C. However, from an energy-saving perspective, the temperature is not higher than 1250°C. It is understood that temperatures higher than 1250°C are also feasible and can produce prebaked anodes with excellent performance. In one embodiment, the firing time during the firing stage at the maximum temperature is 10 to 54 hours.

[0041] In one embodiment, during the baking process of the dried and cured resin anode preform, the resin anode preform is placed in a cover.

[0042] In one embodiment, the firing stage lasts for 30 to 72 hours.

[0043] In one embodiment, the temperature in the cooling stage is 400-1250°C.

[0044] In one embodiment, the cooling stage adopts natural cooling, air cooling or forced cooling.

[0045] In one embodiment, a tunnel kiln is used to dry, solidify and bake the resin anode preform.

[0046] In one embodiment, the heating operation is performed by means of a low-temperature preheating zone of a tunnel kiln.

[0047] In another aspect of the present application, a resin prebaked anode is provided, which is prepared by the above method.

[0048] The beneficial effects of this application are:

[0049] 1. Improve product quality

[0050] A flash curing process pre-forms a hard shell structure on the surface of the resin anode green body, effectively overcoming the cracking and slagging caused by the insufficient bonding strength of phenolic resin in the temperature range of 60-80°C. In some preferred embodiments, the use of a cover eliminates the risk of oxidation of the resin anode preform during the baking process, significantly improving the integrity and stability of the product and significantly increasing the qualified rate.

[0051] 2. Improve production efficiency

[0052] By introducing flash solidification technology, in some preferred implementations, the complex and time-consuming process of filling with metallurgical coke, a traditional process, can be effectively circumvented, significantly reducing processing time. Furthermore, by utilizing the waste heat from the roasting kiln or roaster for drying, the roasting process is deeply optimized, significantly reducing the roasting cycle from nearly a month to less than five days. This not only significantly increases the production capacity of the roasting kiln or roaster, especially the capacity utilization rate of tunnel kilns, but also helps companies double their output within the same production cycle, significantly enhancing their market responsiveness and overall competitiveness.

[0053] 3. Reduce environmental pollution

[0054] In some preferred embodiments, the use of filler metallurgical coke in traditional processes can be reduced or even eliminated, reducing dust generation and pollutant emissions from metallurgical coke roasting, improving the workshop working environment, and lowering environmental treatment costs. This makes the entire production process more environmentally friendly, complies with current environmental protection policies, and promotes the sustainable development of the enterprise.

[0055] 4. Save energy and costs

[0056] There is no need to separately perform curing and drying of the resin anode green body, and the baking time is shortened, which can greatly shorten the time of the entire process, save production cycles, and reduce production costs.

[0057] In some embodiments, the waste heat from the roasting furnace or kiln is used for drying, thereby recycling energy and reducing energy consumption. In addition, protective covers such as silicon carbide covers are reusable, reducing the use of disposable materials and lowering production costs.

[0058] 5. Optimize the performance of electrolytic aluminum

[0059] Firing resin anodes at high temperatures produces a lower resistivity than traditional methods. When used in electrolytic aluminum, this technology not only saves energy but also purifies the molten aluminum, effectively improving the efficiency of electrolytic aluminum and bringing greater economic benefits to aluminum producers. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 Photograph of the resin prebaked anode obtained by the method of Example 1;

[0061] Figure 2 Photograph of the resin prebaked anode obtained by the method of Example 6;

[0062] Figure 3 Photograph of the resin prebaked anode obtained by the method of Comparative Example 3;

[0063] Figure 4 . Photo of the resin prebaked anode obtained by the method of Comparative Example 1. DETAILED DESCRIPTION

[0064] The technical solutions of the present application will be clearly and completely described below in conjunction with specific embodiments, but those skilled in the art will understand that the embodiments described below are part of the embodiments of the present application, rather than all of the embodiments, and are only used to illustrate the present application, and should not be considered as limiting the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application. If the specific conditions are not specified in the embodiments, proceed according to conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified in the equipment or instruments used, they are all conventional products that can be purchased commercially.

[0065] To overcome the problem of phenolic resin's poor bonding performance within a specific temperature range, traditional processes typically employ metallurgical coke filling into carbon blocks to provide structural support. However, this traditional solution has significant drawbacks: First, the introduction of metallurgical coke filling not only increases the complexity of the production process but also significantly occupies a large amount of space within the tunnel kiln, significantly reducing space utilization and hindering further improvements in kiln production efficiency. Second, the dust pollution generated during the filling process is a significant problem, and metallurgical coke can release harmful substances during the high-temperature roasting stage, leading to a deterioration in the overall production environment and a sharp increase in environmental pressure. For example, some prebaked anode manufacturers using this process have long been plagued by dust pollution in their production workshops, resulting in a harsh working environment that poses a potential threat to the health of frontline workers and incurs high environmental protection costs. Furthermore, even with the implementation of metallurgical coke filling, it is still difficult to effectively prevent cracks in the carbon blocks, resulting in a high rate of product defects.

[0066] To this end, the present application proposes a method for preparing a resin pre-baked anode, which solidifies the surface structure of the resin anode green body by a flash burning method and then bakes it.

[0067] In some embodiments, the method for preparing the resin prebaked anode comprises:

[0068] preparing a resin anode green body;

[0069] Flash-burning the surface of the resin anode green body to form a hard shell structure on the surface of the resin anode green body to obtain a resin anode preform;

[0070] drying and curing the resin anode preform;

[0071] The dried and solidified resin anode preform is baked.

[0072] In the solution of the present application, the applicant unexpectedly discovered that by flash-treating the surface of the resin anode green body, the product qualification rate of the resin prebaked anode can be significantly improved, from approximately 10% to over 80%, for example, 85%, 90%, 95%, or even 98%, 99%, or 100%. In addition, the flash-treating also helps improve the performance of the resulting resin prebaked anode, such as its apparent density, compressive strength, resistivity, and ash content.

[0073] In some embodiments, after the flash curing, drying and curing are performed, and then roasting is performed. The drying and curing step can be performed using steam heating or the like, or it can be performed by making full use of the waste heat of a roasting kiln or roasting furnace, such as using the waste heat of a tunnel kiln for roasting, or a combination of the two methods.

[0074] In some embodiments, the roasting stage can be carried out using a conventional kiln, among which a tunnel kiln is preferred. The inventors have found that after flash curing, the roasting time using a tunnel kiln is short, energy saving and cost reduction are achieved, and the obtained resin prebaked anode has a lower resistivity and better performance.

[0075] In some embodiments, the raw materials of the resin anode green body include a binder and an aggregate.

[0076] In some embodiments, the raw materials of the resin anode green body are dry-mixed and / or wet-mixed by a mixing device; the mixing device is a device commonly used or well-known to those skilled in the art, which is mainly used for mixing materials with a certain viscosity or high viscosity (such as asphalt, etc.), such as a kneader, internal mixer, screw extruder, etc.

[0077] In some embodiments, the weight ratio of the binder in the raw material is 5-40%, such as 5-30%, 5-20%, 5-18% or any range within the range of 5-40%; such as 5%, 7%, 9%, 11%, 13%, 15%, 17%, 19%, 21%, 23%, 25%, 27%, 29%, 31%, 33%, 35%, 37%, 39%, 40% or any weight ratio within the range of 5-40%. In some preferred embodiments, the weight ratio of the binder in the raw material is 5-20%; in some more preferred embodiments, the mass ratio of the binder in the raw material is 5-18%. In some embodiments, the weight ratio of the aggregate in the raw material is 60-95%, such as 60-95%, 70-95%, 80-95%, 85-95%, or any weight ratio range within the range of 60-95%, and specifically 60%, 63%, 65%, 67%, 69%, 71%, 73%, 75%, 77%, 79%, 81%, 83%, 85%, 87%, 89%, 91%, 93%, 95%, or any weight ratio within the range of 60-95%. In some preferred embodiments, the weight ratio of the aggregate in the raw material is 82-95%.

[0078] In some embodiments, the binder is a phenolic resin.

[0079] In the present application, there is no other special limitation on the selection of the phenolic resin; for example, the phenolic resin can be a phenolic resin commonly used in the art, such as one or more of a biomass-modified phenolic resin, an asphalt-modified phenolic resin, a coal tar-modified phenolic resin, an alkylphenol-modified phenolic resin, and a rubber-modified phenolic resin. In some embodiments, the phenolic resin has a carbon residue rate of 48%-55%, such as 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, etc.; in some embodiments, the phenolic resin has a viscosity of 16000-19000 cp / 25°C, such as 16000 cp / 25°C, 16500 cp / 25°C, 17000 cp / 25°C, 17500 cp / 25°C, 18000 cp / 25°C, 18500 cp / 25°C, 19000 cp / 25°C, etc. In some embodiments, the phenolic resin has a carbon residue rate of 48%-55% and a viscosity of 16,000-19,000 cp / 25°C.

[0080] In some embodiments, the binder is a mixture of phenolic resin and coal tar.

[0081] In some embodiments, the coal tar accounts for less than 5 wt% of the raw material (e.g., the raw material includes a binder and an aggregate), for example, preferably less than 2 wt%, and more preferably less than 1 wt%; specifically, for example, it can be 4.8 wt%, 4.5 wt%, 4.2 wt%, 4 wt%, 3.8 wt%, 3.5 wt%, 3.2 wt%, 3.0 wt%, 2.8 wt%, 2.5 wt%, 2 wt%, 1.8 wt%, 1.5 wt%, 1.3 wt%, 1.0 wt%, 0.9 wt%, 0.8 wt%, 0.7 wt%, 0.6 wt%, 0.5 wt%, 0.4 wt%, 0.3 wt%, 0.2 wt%, 0.1 wt%, 0 wt%, etc.

[0082] In some embodiments, the aggregate is selected from petroleum coke, or a mixture of petroleum coke and carbon materials such as graphite chips and carbon nanotubes. In some embodiments, the petroleum coke accounts for more than 50wt% of the mixture; in some preferred embodiments, the petroleum coke accounts for more than 80wt% of the mixture. In some embodiments, the petroleum coke accounts for more than 50wt%, more than 52wt%, more than 55wt%, more than 58wt%, more than 60wt%, more than 63wt%, more than 65wt%, more than 67wt%, more than 70wt%, more than 72wt%, more than 75wt%, more than 78wt%, more than 80wt%, more than 83wt%, more than 85wt%, more than 87wt%, more than 90wt%, more than 92wt%, more than 94wt%; for example, 51wt%, 52wt%, 53wt%, 54wt%, 55wt% %, 56wt%, 58wt%, 59wt%, 60wt%, 62wt%, 63wt%, 64wt%, 65wt%, 66wt%, 67wt%, 69wt%, 70wt%, 71wt%, 72wt%, 73wt%, 74wt%, 75 wt%, 77wt%, 78wt%, 79wt%, 80wt%, 82wt%, 83wt%, 84wt%, 85wt%, 86wt%, 87wt%, 88wt%, 90wt%, 91wt%, 92wt%, 93wt%, 94wt%, etc.

[0083] In some embodiments, the true density of the petroleum coke is 2 to 2.5 g / cm 3 Specific example can be 2g / cm 3 , 2.1g / cm 3 , 2.2g / cm 3 , 2.3g / cm 3 , 2.4g / cm 3 , 2.5g / cm 3 or 2-2.5 g / cm 3In some embodiments, the powder resistivity of the petroleum coke is 300-500 μΩ·m; for example, it can be 300 μΩ·m, 320 μΩ·m, 340 μΩ·m, 360 μΩ·m, 370 μΩ·m, 380 μΩ·m, 390 μΩ·m, 400 μΩ·m, 410 μΩ·m, 420 μΩ·m, 430 μΩ·m, 450 μΩ·m, 470 μΩ·m, 490 μΩ·m, 500 μΩ·m, or any value within the range of 300-500 μΩ·m.

[0084] In one embodiment, the aggregate may also contain spent prebaked anodes, for example, spent prebaked anodes with a suitable particle size are used as aggregate.

[0085] In some embodiments, the temperature of the flash treatment is 300-500°C, 320-480°C, 350-450°C, 370-430°C, 390-410°C, or any temperature range within the range of 300-500°C; for example, the temperature of the calcination treatment is 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, or any temperature within the range of 300-500°C.

[0086] As used herein, "flash treatment" refers to a non-continuous or non-extended burning treatment.

[0087] The applicant has discovered that the flash treatment temperature can significantly improve the product qualification rate of the obtained resin prebaked anodes, increasing the product qualification rate from 40-50% to over 80%, for example, 85%, 90%, 95%, or even 98%, 99%, or 100%. In addition, the flash treatment temperature is also conducive to improving the performance of the obtained resin prebaked anodes, such as their apparent density, compressive strength, resistivity, and ash content.

[0088] In some embodiments, the flash treatment is performed 2 to 3 times; for example, 2 times or 3 times.

[0089] In some embodiments, when the flash treatment is performed multiple times, the time interval between two adjacent flash treatments is 10-30 min, 12-28 min, 15-25 min, 17-22 min or any time range within the range of 10-30 min; for example, 10 min, 12 min, 14 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min, 30 min or any time interval within the range of 10-30 min.

[0090] The applicant found that under the above-mentioned number and time interval of flash treatment, the product qualification rate of the obtained resin prebaked anode can be significantly improved, and the performance of the obtained resin prebaked anode (such as its apparent density, its compressive strength, resistivity and ash content, etc.) can be ensured to be excellent.

[0091] In some embodiments, the thickness of the hard shell layer on the surface of the resin anode preform is 1-3 mm, 1.2-2.7 mm, 1.5-2.5 mm, 1.8-2.3 mm, or any thickness range within the range of 1-3 mm. For example, the hard shell layer may be 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3.0 mm, or any thickness within the range of 1-3 mm.

[0092] In some embodiments, the hardness of the hard shell layer on the surface of the resin anode preform is 20-37 MPa, 25-35 MPa, 28-32 MPa or any hardness range within the range of 20-37 MPa; in some preferred embodiments, the hardness of the hard shell layer on the surface of the resin anode preform is 28-32 MPa; in a specific embodiment, the hardness of the hard shell layer on the surface of the resin anode preform is 20 MPa, 21 MPa, 22 MPa, 23 MPa, 24 MPa, 25 MPa, 26 MPa, 27 MPa, 28 MPa, 29 MPa, 30 MPa, 31 MPa, 32 MPa, 33 MPa, 34 MPa, 35 MPa, 36 MPa, 37 MPa or any hardness range within the range of 20-37 MPa.

[0093] In some embodiments, the resin anode preform can be dried and cured by covering it with a cover and then heating it (e.g., by steam heating); or by adding a filler with thermal energy (e.g., heat energy) into a sagger and preheating the filler. The applicant has found that both of the above methods can produce resin prebaked anodes with excellent performance, and the product qualification rate is maintained at a high level (at least 80%, and even as high as 98%, 99%, or even 100%).

[0094] In some embodiments, drying and curing the resin anode preform comprises:

[0095] placing the resin anode preform in the cover;

[0096] The resin anode preform covered with the cover body is heated.

[0097] In some embodiments, the drying and curing, as well as the calcining, can be performed in a tunnel kiln. For example, the drying and curing are performed in a low-temperature preheating zone of the tunnel kiln, and the calcining is performed mainly in a high-temperature zone of the tunnel kiln.

[0098] In some embodiments, a contact interface is constructed between the cover and the resin anode preform, and the interface is characterized by a continuous fitting morphology without macroscopic gaps.

[0099] In some embodiments, a contact interface is constructed between the cover and the resin anode preform, and the interface is characterized by a discontinuous fitting form with a macro gap, and the macro gap is filled with high temperature resistant particles at the contact interface, thereby making it exhibit a continuous fitting form.

[0100] In some embodiments, the high-temperature resistant particulate matter used to fill the macroscopic gaps is, for example, metallurgical coke.

[0101] In some embodiments, the cover is made of silicon carbide. In some embodiments, the cover is made of stainless steel. In some embodiments, the cover is made of a combination of silicon carbide and stainless steel; for example, some areas may be made of stainless steel, while others may be made of silicon carbide. It should be noted that there are no restrictions on the choice of cover material; ideal results can be achieved using silicon carbide and / or stainless steel.

[0102] In some embodiments, the temperature set for the heating operation is 140-220°C, 160-220°C, 180-220°C, 200-220°C or any temperature range within the range of 140-220°C; in a specific embodiment, the temperature set for the heating operation is 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C or any temperature within the range of 140-220°C.

[0103] In some embodiments, the heating operation time is 10 to 24 hours, 10 to 20 hours, 10 to 18 hours, 10 to 15 hours or any time range within the range of 10 to 24 hours; for example, it can be 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours or any time within the range of 10 to 24 hours.

[0104] In some embodiments, drying and curing the resin anode preform comprises:

[0105] The resin anode preform is covered with a filler carrying heat energy, and the filler provides the resin anode preform with heat energy required for drying by heat conduction. In addition, the filler also has the effect of preventing the resin anode preform from being oxidized.

[0106] In some embodiments, the resin anode preform is placed in a sagger for drying and curing.

[0107] In some embodiments, the filler is metallurgical coke; in some embodiments, the filler is river sand; in some embodiments, the filler is metallurgical coke and / or river sand.

[0108] In some embodiments, the temperature corresponding to the thermal energy possessed by the filler is 180-220°C, 190-220°C, 200-220°C, 210-220°C or any temperature range within the range of 180-220°C; in a specific embodiment, the temperature corresponding to the thermal energy possessed by the filler is 180°C, 190°C, 200°C, 210°C, 220°C or any temperature within the range of 180-220°C.

[0109] In some embodiments, before the roasting, it also includes: preheating the dried and cured resin anode preform, wherein the preheating temperature is 300-800°C, 350-750°C, 400-700°C, 450-650°C, 500-600°C or any temperature range within the range of 300-800°C; for example, it can be 300°C, 320°C, 340°C, 360°C, 380°C, 400°C, 430°C, 460°C, 490°C, 510°C, 530°C, 550°C, 570°C, 590°C, 600°C, 620°C, 640°C, 660°C, 680°C, 710°C, 750°C, 780°C, 800°C or any temperature within the range of 300-800°C. It is understandable that in actual operation, the temperature may not stabilize at a specific temperature value, for example, it may fluctuate within a smaller temperature range, such as fluctuating within a temperature difference of no more than 100°C, no more than 80°C, no more than 60°C, no more than 50°C, etc.; in actual operation, the temperature may also be at a stable temperature point value; the specific point value is as described above.

[0110] In some embodiments, the firing of the preheated, dried and cured resin anode preform includes a firing stage and a cooling stage.

[0111] In this application, the firing stage is a gradient temperature increase. For example, firing is performed at a first temperature for a period of time, then at a second temperature for a period of time, and then at a third temperature for a period of time. Furthermore, the first temperature is lower than both the second and third temperatures, and the second temperature is lower than the third temperature. However, during this process, the applicant discovered that the maximum temperature should not be too low, for example, not less than 1150°C.

[0112] In some embodiments, the maximum temperature of the firing stage is at least 1150°C, such as 1150-1200°C, 1150-1250°C, or 1200-1250°C. Further examples include 1150°C, 1170°C, 1190°C, 1210°C, 1230°C, 1250°C, 1270°C, or 1300°C, or even higher. In some embodiments, the firing time at the maximum temperature during the firing stage is 10-54 hours, such as 10 hours, 13 hours, 16 hours, 19 hours, 22 hours, 25 hours, 28 hours, 30 hours, 33 hours, 36 hours, 39 hours, 42 hours, 45 hours, 48 ​​hours, 51 hours, or 54 hours, or any time within the range of 10-54 hours.

[0113] In some embodiments, during the baking process of the dried and cured resin anode preform, the resin anode preform is placed in a cover to further prevent the resin anode preform from being oxidized at high temperature.

[0114] In some embodiments, the temperature of the firing stage is 800-1250° C.; for example, it can be 800° C., 900° C., 1000° C., 1150° C., 1170° C., 1190° C., 1210° C., 1230° C., 1250° C., etc. In some embodiments, the duration of the firing stage is any time range within the range of 30-72 hours, 30-66 hours, 30-60 hours, 30-54 hours, 30-48 hours, 30-42 hours, 30-36 hours, or 30-72 hours; in a specific embodiment, for example, it can be 30 hours, 33 hours, 36 hours, 39 hours, 42 hours, 45 hours, 48 ​​hours, 51 hours, 54 hours, 57 hours, 60 hours, 63 hours, 66 hours, 69 hours, 72 hours, or any time range within the range of 30-72 hours.

[0115] In some embodiments, the temperature of the cooling stage is 400-1250°C, 400-1150°C, 400-850°C, 400-650°C, 400-550°C, 400-450°C or any time range within the range of 400-1250°C; for example, it can be 400°C, 500°C, 600°C, 700°C, 800°C, 900°C, 1000°C, 1100°C, 1200°C, 1250°C or any temperature within the range of 400-1250°C.

[0116] As is known in the art, the cooling stage can be performed by methods well known to those skilled in the art. In some embodiments, the cooling stage adopts natural cooling; in some embodiments, the cooling stage adopts air cooling; in some embodiments, the cooling stage adopts forced cooling.

[0117] In some embodiments, a tunnel kiln is used to dry, solidify and bake the resin anode preform.

[0118] In some embodiments, the heating operation is performed via a low-temperature preheating zone of a tunnel kiln.

[0119] In another aspect of the present application, a resin prebaked anode is provided, wherein the resin prebaked anode is prepared by the above method.

[0120] Example 1

[0121] A method for preparing a resin prebaked anode comprises the following steps:

[0122] S1 resin anode green preparation

[0123] Petroleum coke is added into a kneader and dry-mixed for 15 minutes to obtain a uniformly mixed dry mixed material. Phenolic resin is preheated to 30° C. and then added into the kneader and wet-mixed with the uniformly mixed dry mixed material for 15 minutes to obtain a uniformly mixed paste. Among the raw materials, petroleum coke accounts for 90wt% and phenolic resin accounts for 10wt%.

[0124] The kneaded paste is added to a high-pressure vacuum forming machine for molding, the vacuum degree of the high-pressure vacuum forming machine is -0.02MPa, and the molding pressure is 1000 tons to obtain a resin anode green body precursor;

[0125] Among them, the true density of petroleum coke is 2.08g / cm 3 , powder resistivity 400μΩ·m.

[0126] The residual carbon rate of the phenolic resin is 48% to 55%, and the viscosity is 16000 to 19000 cp / 25°C.

[0127] S2 flash curing treatment

[0128] The prepared resin anode green body is placed on the operating table and the anode surface is evenly flash-burned using a flame torch. The flame temperature of the flame torch is controlled at approximately 400°C, and the distance between the flame torch and the anode surface is maintained at approximately 5 cm. Each flame spraying lasts for 3 to 5 seconds, with the next flame spraying performed after an interval of 20 minutes. This is repeated three times until a 2 mm thick hard shell structure is formed on the anode surface. The strength is approximately 30 MPa as measured by a concrete rebound hammer, thus obtaining a resin anode preform.

[0129] S3 Drying

[0130] After completing the flash curing process, ensure that the silicon carbide cover fits tightly to the anode without leaving any large gaps to effectively prevent oxidation.

[0131] The resulting resin anode preform is placed in a specially made silicon carbide cover. This silicon carbide cover is then transported to the tunnel kiln's low-temperature preheating zone, where the temperature gradually rises from room temperature to a final temperature of 200±20°C. The preform remains in this zone for 12 hours, drying using residual heat to further solidify the phenolic resin and increase anode strength.

[0132] S4 preheating and high temperature zone roasting

[0133] After drying, the resin anode preforms are transported through the tunnel kiln's conveyor system into the preheating zone. The preheating zone is heated from 300°C to 800°C, maintaining temperatures at 300-400°C for 4 hours, 400-500°C for 4 hours, 500-600°C for 5 hours, 600-700°C for 5 hours, and 700-800°C for 6 hours to further expel volatile components from the resin and enhance its structural stability.

[0134] When the resin anode preform enters the high temperature zone, the temperature range of the high temperature zone is between 800-1250℃, specifically, it is maintained at 800℃-900℃ for 5h, maintained at 900-1000℃ for 6h, maintained at 1000-1100℃ for 6h, baked at 1100-1150℃ for 6h, and baked at 1150-1250℃ for 13h. The total baking time in this high temperature zone temperature range is 36 hours to complete the baking process of the anode.

[0135] S5 kiln discharge and finished product processing

[0136] After the roasting is completed, the resin pre-baked anode enters the cooling zone along with the conveying system, where it is cooled to below 400°C. After the cooling is completed, the silicon carbide cover is directly removed to obtain the final resin pre-baked anode product; see the specific product photos for details. Figure 1 The obtained resin anode has a smooth appearance without any shell shedding or local cracks.

[0137] Example 2

[0138] The preparation process is the same as that of Example 1, except that the time and number of ignition times in the flash curing step are different, specifically:

[0139] S2 flash curing treatment

[0140] The prepared resin anode green body is placed on the operating table and the anode surface is evenly flash-burned using a flame torch. The flame temperature of the flame torch is controlled at approximately 400°C, and the distance between the flame torch and the anode surface is maintained at approximately 5 cm. Each flame spraying time is 8 to 10 seconds, and the next flame spraying is performed after an interval of 20 minutes. This is repeated twice until a 1 mm thick hard shell structure is formed on the anode surface. The hardness is approximately 30 MPa as measured by a concrete rebound hammer, thus obtaining a resin anode preform.

[0141] Other steps are the same as in Example 1.

[0142] Example 3

[0143] The preparation process is the same as that of Example 1, except that the time and number of ignition times in the flash curing step are different, specifically:

[0144] S2 flash curing treatment

[0145] The prepared resin anode green body is placed on the operating table and the anode surface is evenly flash-burned using a flame torch. The flame temperature of the flame torch is controlled at approximately 400°C, and the distance between the flame torch and the anode surface is maintained at approximately 5 cm. Each flame spraying lasts for 8 to 10 seconds, with the next flame spraying performed after an interval of 20 minutes. This is repeated three times until a 1 mm thick hard shell structure is formed on the anode surface. The hardness is approximately 30 MPa as measured by a concrete rebound hammer, thus obtaining a resin anode preform.

[0146] Other steps are the same as in Example 1.

[0147] Example 4

[0148] The preparation process is the same as that of Example 1, except that:

[0149] S3 Drying

[0150] After flash curing, the obtained resin anode preform is placed in a special silicon carbide cover and heated by steam, with the temperature gradually increasing from room temperature to 150°C for 4 hours for drying and curing.

[0151] Example 5

[0152] The preparation process is the same as that of Example 1, except that the drying step is different, specifically:

[0153] S3 Drying

[0154] After the flash curing process is completed, the obtained resin anode preform is placed in a silicon carbide sagger without using a silicon carbide cover;

[0155] The metallurgical coke with temperature on the outside of the carbon blocks discharged from the kiln after the aforementioned flash treatment is sucked out by a suction overhead crane. The filling material temperature is 220±20℃ and is simultaneously loaded into the silicon carbide sagger containing the resin anode preform. The hot filling material transfers part of its temperature to the resin anode preform, thereby achieving drying and curing.

[0156] Example 6

[0157] The preparation process is the same as that of Example 1, except that the ignition temperature in the flash curing step is different, specifically:

[0158] Place the prepared resin anode green body on the operating table and use a flame torch to evenly flash burn the anode surface. Control the flame temperature of the flame torch to 300℃, keep the distance between the flame torch and the anode surface at about 5cm, and spray for 3 to 5 seconds each time. Repeat the spray for 20 minutes and repeat 3 times to form a 2mm thick hard shell structure on the anode surface. The hardness is about 28MPa as measured by the concrete rebound tester. The resin anode preform is obtained. Figure 2 The obtained resin anode has a smooth appearance without any shell shedding or local cracks.

[0159] Example 7

[0160] The preparation process is the same as that of Example 1, except that the ignition temperature in the flash curing step is different, specifically:

[0161] The prepared resin anode green body is placed on the operating table and the anode surface is evenly flash-burned using a flame torch. The flame temperature of the flame torch is controlled between 500°C and the distance between the flame torch and the anode surface is maintained at about 5 cm. Each flame spraying time is 3 to 5 seconds, and the next flame spraying is performed after an interval of 20 minutes. This is repeated three times until a 2 mm thick hard shell structure is formed on the anode surface. The hardness is approximately 33 MPa as measured by a concrete rebound hammer, thus obtaining a resin anode preform.

[0162] Example 8

[0163] The preparation process is the same as that of Example 1, except that the calcination temperature in the high-temperature zone calcination step is different, specifically:

[0164] When the resin anode preform enters the high temperature zone, the temperature of the high temperature zone is 800-1100℃, and it is kept at 800-900℃ for 8 hours, at 900-1000℃ for 10 hours, and at 1000-1100℃ for 30 hours to complete the anode baking process.

[0165] Example 9

[0166] The preparation process is the same as that of Example 1, except that the calcination temperature in the high-temperature zone calcination step is different, specifically:

[0167] When the resin anode preform enters the high temperature zone, it is 800-950℃, maintained at 800-900℃ for 8 hours, and maintained at 900-1000℃ for 52 hours to complete the anode baking process.

[0168] Comparative Example 1

[0169] The preparation process is the same as that of Example 1, except that the resin anode green body prepared in S1 is directly dried without flash curing. The product photo of the final resin anode is shown in Figure 4 The obtained resin anode has obvious local cracks on its appearance.

[0170] Comparative Example 2

[0171] The preparation process is the same as that of Example 1, except that the ignition temperature in the flash curing step is different, specifically:

[0172] The prepared resin anode green body is placed on the operating table and the anode surface is evenly flash-burned using a flame torch. The flame temperature of the flame torch is controlled at approximately 270°C, and the distance between the flame torch and the anode surface is maintained at approximately 5 cm. Each flame spraying lasts for 3 to 5 seconds, with the next flame spraying performed after an interval of 20 minutes. This is repeated three times until a 2 mm thick hard shell structure is formed on the anode surface. The hardness is approximately 24 MPa as measured by a concrete rebound hammer, thus obtaining a resin anode preform.

[0173] Comparative Example 3

[0174] The preparation process is the same as that of Example 1, except that the ignition temperature in the flash curing step is different, specifically:

[0175] Place the prepared resin anode green body on the operating table and use a flame torch to evenly flash the anode surface. Control the flame temperature of the flame torch at about 520℃, keep the distance between the flame torch and the anode surface at about 5 cm, and spray for 3 to 5 seconds each time. After 20 minutes, spray the next time. Repeat 3 times to form a 2mm thick hard shell structure on the anode surface. The hardness is about 38MPa as measured by the concrete rebound tester. The resin anode preform is obtained. The product photo of the final resin anode is shown in Figure 3 The hardness of the hard shell of the obtained resin anode is too high, and the hard shell has local shedding.

[0176] Comparative Example 4

[0177] The preparation process is the same as that of Example 1, except that the calcination temperature in the high-temperature zone calcination step is different, specifically:

[0178] When the resin anode preform enters the high temperature zone, the temperature of the high temperature zone is maintained at 800°C, and it is baked at this temperature for 72 hours to complete the baking process of the anode.

[0179] Example 10

[0180] The resin prebaked anode is prepared in a ring furnace, specifically:

[0181] S3 Drying

[0182] After flash curing, the obtained resin anode preform is placed in a special silicon carbide cover and heated by steam. The temperature is gradually increased from room temperature to 150±10°C for 4 hours for drying and curing.

[0183] S4 preheating and high temperature zone roasting

[0184] After drying, the silicon carbide cover is removed and the resin anode preform is placed in a ring furnace through a fixture.

[0185] Among them, the roasting procedure of the ring furnace is as follows:

[0186] Temperature range Heating rate (℃ / hour) Calcination time (hours) Room temperature - 300℃ 6 5 300℃-800℃ 8 24 800℃-1200℃ 10 120 1200℃ insulation for 24 hours -- 168

[0187] S5 kiln discharge and finished product processing

[0188] After the calcination is completed, the resin prebaked anode begins to cool down and is cooled to below 400°C in the cooling zone to obtain the final resin prebaked anode product.

[0189] Example 11

[0190] The shuttle kiln is used to prepare resin prebaked anodes, specifically:

[0191] S3 Drying

[0192] After flash curing, the obtained resin anode preform is placed in a special silicon carbide cover and heated by steam. The temperature is gradually increased from room temperature to 150±10°C for 4 hours for drying and curing.

[0193] S4 preheating and high temperature zone roasting

[0194] After drying, the silicon carbide cover is removed and the resin anode preform is placed in the shuttle kiln through a fixture.

[0195] Among them, the shuttle kiln roasting procedure is as follows:

[0196] Temperature range (℃) Calcination time (hours) Room temperature -200 2 200-300 3 300 constant temperature 4 300-500 3 500 constant temperature 5 500-800 4 800 constant temperature 3 800-950 3 950-1120 3 1120 constant temperature 50

[0197] S5 kiln discharge and finished product processing

[0198] After the calcination is completed, the resin prebaked anode begins to cool down and is cooled to below 400°C in the cooling zone to obtain the final resin prebaked anode product.

[0199] Experimental example

[0200] 1) Flash curing effect test

[0201] Fifty resin anode preforms, each after drying, were collected from the Example and the Comparative Example. The surface condition of the dried resin anode preforms was observed. Any cracks or debris was considered unqualified. The qualified rate was calculated. The qualified rate (%) = number of qualified resin anode preforms / total number of resin anode preforms tested × 100%. The results are shown in Table 1.

[0202] Table 1 Qualification rate of dried resin anode preforms

[0203] Example Pass rate, % Example 1 The scrap rate is reduced and the qualified rate is increased to about 98% Example 2 The scrap rate is reduced and the qualified rate is increased to about 80%. Example 3 The scrap rate is reduced and the qualified rate is increased to about 80%. Example 6 The scrap rate is reduced and the qualified rate is increased to about 90%. Example 7 The scrap rate is reduced and the qualified rate is increased to about 88% Comparative Example 1 The pass rate is about 10% Comparative Example 2 The pass rate is about 50% Comparative Example 3 The pass rate is about 40%

[0204] 2) Test the performance of resin prebaked anode

[0205] The apparent density, CO2 reactivity, compressive strength, resistivity and ash content of the resin prebaked anode with no cracks or gaps and a rounded appearance were tested. The results are shown in Table 2.

[0206] The detection methods for CO2 reactivity, compressive strength, resistivity, apparent density and ash content shall be carried out in accordance with the detection methods in YS / T63.12-2024; the detection method for resistivity shall be a resistance tester.

[0207] Table 2 Properties of resin prebaked anodes

[0208]

[0209] Although the embodiments of the present application are described above by way of example, the present application is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and instructive, and not restrictive. A person of ordinary skill in the art, guided by this specification and without departing from the scope of protection of the claims of this application, may devise various other forms, all of which fall within the scope of protection of this application.

Claims

1. A method for preparing a resin prebaked anode, comprising: preparing a resin anode green body; Flash-burning the surface of the resin anode green body to form a hard shell structure on the surface of the resin anode green body to obtain a resin anode preform; drying and curing the resin anode preform; The dried and solidified resin anode preform is baked.

2. The preparation method according to claim 1, wherein the temperature of the flash treatment is 300-500°C.

3. The preparation method according to claim 1, wherein the number of flash treatments is 2 to 3; Preferably, the time interval between two adjacent flash treatments is 10 to 30 minutes.

4. The preparation method according to claim 1, wherein the thickness of the hard shell layer on the surface of the resin anode preform is 1 to 3 mm; Preferably, the hardness of the hard shell layer on the surface of the resin anode preform is 20-37 MPa.

5. The preparation method according to claim 1, wherein drying and curing the resin anode preform comprises: placing the resin anode preform in the cover; The resin anode preform covered with the cover body is heated.

6. The preparation method according to claim 1, wherein drying and curing the resin anode preform comprises: The resin anode preform is covered with a filler carrying heat energy, and the filler provides the resin anode preform with heat energy required for drying through heat conduction.

7. The preparation method according to claim 1, further comprising, before the calcination: The dried and cured resin anode preform is preheated at a temperature of 300-800°C.

8. The preparation method according to claim 1, wherein the step of baking the dried and solidified resin anode preform comprises a firing stage and a cooling stage; Preferably, the maximum temperature of the firing stage is at least 1150°C; More preferably, in the firing stage, the firing time at the highest temperature is 10 to 54 hours.

9. The preparation method according to claim 1, wherein the resin anode preform is dried, solidified and fired in a tunnel kiln.

10. A resin prebaked anode, wherein the resin prebaked anode is prepared by the preparation method according to any one of claims 1 to 9.

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