Green preparation method of low-carbon prebaked anode based on biomass composite bonding system

Abstract

The invention discloses a green preparation method of a low-carbon prebaked anode based on a biomass composite bonding system. According to the invention, through an open-phase biomass-based composite bonding system (prepared from lignosulfonate, nanocellulose crystal, bio-based epoxy crosslinking agent and pyrolytic carbon precursor) and a matched process (through coupling of the bio-based epoxy crosslinking agent and a gradient roasting process), coal pitch can be reduced or even completely not used; the problems of high pollution, high cost and insufficient biomass material forming strength of a traditional coal pitch binder are successfully solved.

Description

Technical Field

[0001] The present invention relates to the technical field of manufacturing pre-baked anodes for aluminum electrolysis, and particularly to a green preparation method of low-carbon pre-baked anodes based on a biomass composite binder system. Background Art

[0002] As the core material in the aluminum electrolysis industry, the performance of pre-baked anodes directly determines the energy consumption efficiency and carbon emission level of electrolytic aluminum. Currently, the industry generally uses petroleum coke as the aggregate and coal tar pitch as the binder (accounting for 15 - 20%), and prepares pre-baked anodes through processes such as kneading, forming, and high-temperature roasting. However, traditional coal tar pitch binders have significant defects in terms of environmental protection and performance: on the one hand, coal tar pitch contains strong carcinogens such as benzo[a]pyrene, which will release a large amount of sulfur oxides (SO x ), nitrogen oxides (NO x ) and polycyclic aromatic hydrocarbons (PAHs) during high-temperature roasting, causing serious pollution to the production environment and the surrounding ecosystem, and posing extremely high health risks to workers under long-term exposure; on the other hand, the anisotropic carbon structure formed after the coking of coal tar pitch results in a generally over 28% porosity of pre-baked anodes, insufficient thermal shock resistance, and cracks and spalling are likely to occur in the high-temperature environment of the electrolytic cell, accelerating anode consumption (the industry average consumption rate reaches 450 kg / t-Al), indirectly driving up the production cost of aluminum. In addition, as a petrochemical by-product, the price of coal tar pitch is significantly affected by the production capacity of the coking industry and fluctuations in the international crude oil market, with a price fluctuation range as high as 40% in the past five years, further intensifying the cost control pressure on anode production enterprises.

[0003] In response to the above problems, existing technologies have tried to seek breakthroughs by improving the binder system, but the actual effects still have obvious limitations. For example, the modified asphalt technology reduces the softening point through oxidation treatment or adding tar, which can partially improve the fluidity of the paste, but fails to fundamentally solve the problem of pollutant emissions; synthetic resins (such as phenolic resins) have higher bonding strength and thermal stability, but their raw material cost is about 3 times that of coal tar pitch, and the residual ash (>5%) after high-temperature pyrolysis will block the anode pores, affecting the diffusion of electrolysis reaction gases, and instead reducing the service life of the anode. In recent years, biomass binders have received attention due to their renewable nature and environmental protection potential. However, when directly applying natural polymer materials such as lignin and starch, due to the insufficient rigidity of the molecular chain and the loose structure of the pyrolysis products, the green body compressive strength is generally lower than 8 MPa, unable to meet the mechanical strength requirements of industrial-grade pre-baked anodes (≥35 MPa). In addition, the poor interfacial compatibility between biomass components and petroleum coke aggregates is prone to phase separation during the kneading process, further restricting its large-scale application.

[0004] In summary, it is difficult to achieve a balance among environmental protection, economy, and performance indicators in the existing pre-baked anode technology routes. The traditional coal tar pitch process faces increasingly stringent environmental regulations, while alternative solutions are difficult to promote due to high costs or unqualified performance. As a high-energy-consuming field, the electrolytic aluminum industry urgently needs to reduce the carbon emission intensity per unit aluminum output through material innovation (currently, the indirect CO2 emission per ton of aluminum production is about 12 tons). Therefore, developing a biomass-based alternative binder with low cost, low pollution, and high binding efficiency, and optimizing the pre-baked anode production process accordingly, has become the key direction to break through the industry bottleneck. However, the technical difficulty in this direction lies in how to improve the carbon network continuity after coking while maintaining the thermoplasticity of the binder through molecular design and composite modification of biomass components, so as to balance the green body forming strength and the anode conductivity after roasting. This challenge has not been effectively solved in the existing public research. Summary of the Invention

[0005] In view of the above problems, the present invention provides a green preparation method for low-carbon pre-baked anodes based on a biomass composite binder system. By innovatively developing a biomass-based composite binder system (prepared from lignosulfonate, nanocrystalline cellulose, bio-based epoxy crosslinker, and pyrolytic carbon precursor) and a supporting process (coupling the bio-based epoxy crosslinker with a gradient roasting process), the present invention can reduce or even completely eliminate the use of coal tar pitch, and successfully solves the industry problems of high pollution, high cost of traditional coal tar pitch binders, and insufficient forming strength of biomass materials.

[0006] The technical solution of the present invention is: a green preparation method for low-carbon pre-baked anodes based on a biomass composite binder system, characterized in that the pre-baked anode is prepared from aggregate and biomass binder as the main raw materials through kneading, forming, and high-temperature roasting processes; the raw materials for preparing the pre-baked anode and their weight ratios (according to the paste) are: biomass binder 6%-18%, coal tar pitch 0%-8%, and aggregate 82%-86%.

[0007] Among them, the biomass binder is prepared from 40-60% lignosulfonate, 10-20% nanocrystalline cellulose (NCC), 5-10% bio-based epoxy crosslinker, and 10-30% pyrolytic carbon precursor.

[0008] The aggregate system consists of 85%-100% calcined petroleum coke (fixed carbon content ≥ 98%) and 0%-15% waste baked scraps (broken waste pre-baked anodes).

[0009] Preferably, the above lignosulfonate is a brownish - brown powder, containing sulfonic acid groups (-SO3H), with a sulfonation degree ≥ 1.2 mmol / g, having anionic surface activity, which can prevent cellulose agglomeration, with a molecular weight of 5000 - 8000 Da and a pH of 8 - 10. The above nano - cellulose crystal (NCC) is a white suspension or dry powder, with a crystallinity ≥ 80%, a diameter of 20 - 50 nm, and an aspect ratio > 50, which helps to form a "steel - bar skeleton" structure and inhibits shrinkage and cracking during roasting. The above bio - based epoxy cross - linker is cardanol glycidyl ether, a light - yellow liquid, derived from cardanol extracted from cashew nut shell liquid, with an epoxy value of 0.45 - 0.55 eq / 100 g and a viscosity (at 25 °C) of 1200 - 1500 MPa·s. The above pyrolytic carbon precursor is sucrose - coked fine powder, which is a kind of black amorphous carbon fine powder generated by using sucrose as a raw material through a coking process, with a particle size D 50 = 10 - 15 μm, D 90 <30 μm.

[0010] Preferably, the above calcined petroleum coke is: calcine petroleum coke to 1250 - 1350 °C (volatile matter < 0.5%), crush and classify it and then proportion it; the production method of waste cooked broken pieces is: first, the waste pre - baked anode is coarsely crushed by a jaw crusher, then finely crushed by a pair - roll crusher, crush and classify it and then proportion it. The above proportioning together is specifically as follows: 35% - 40% of coarse particles with a particle size of 4 - 8 mm, 30 - 35% of medium particles with a particle size of 1 - 4 mm, and 25 - 30% of fine powder with a particle size of less than 1 mm.

[0011] Preferably, the above coal tar pitch is medium - temperature pitch, and the index requirements are as follows: softening point 90 - 105 °C, volatile matter < 5%, ash content < 0.5%, moisture content < 0.5%, quinoline insoluble matter < 0.5%, density is 1.2 g / cm 3 - 1.4 g / cm 3 , viscosity (at 150 °C) is 1000 MPa·s - 5000 MPa·s, and carbon content is greater than 60%.

[0012] Preferably, the preparation method of the above biomass binder is: ultrasonically disperse lignosulfonate and NCC in water at 50 - 70 °C to form a uniform colloid, add a bio - based epoxy cross - linker and a pyrolytic carbon precursor, and stir and react at pH = 8 - 10 for 1 - 3 h to generate a three - dimensional network structure, thus preparing the biomass binder for standby.

[0013] The preparation process of the above low - carbon pre - baked anode:

[0014] 1) Kneading

[0015] Dry - mixing stage: Preheat the aggregate to 135 - 170 °C, dry - mix for 15 - 20 minutes, and raise the temperature to 170 - 180 °C to make the aggregate temperature uniform;

[0016] Wet mixing stage: First, add a liquid biomass binder (temperature 60 - 70°C, solid content 60% - 80%) to the aggregate, knead for 5 - 10 minutes, and the final kneading temperature is 135 - 140°C to prevent thermal degradation of the biomass; if coal tar pitch is included, heat it to 170 - 180°C and then add the biomass binder and coal tar pitch, knead for 8 - 25 minutes, and the final kneading temperature is 150 - 155°C to ensure that the pitch fully wets the aggregate; the volatile matter is controlled at 3.0% - 4.5%.

[0017] 2) Shaping

[0018] Vibratory compaction: The vibration frequency is 45 - 50 Hz, the amplitude is 1.2 - 1.8 mm, and the vibration time is 2 - 3 minutes. The density of the green block formed is ≥1.50 g / cm 3 ;

[0019] Molding and strengthening: The molding pressure is 15 - 30 MPa, and the pressure is maintained for 3 - 5 minutes. The final density of the green block is ≥1.58 g / cm 3 , with an allowable deviation of ±0.03.

[0020] 3) Baking

[0021] Adopting a baking curve different from the conventional anode baking curve, after repeated tests, a gradient heating curve as shown in Table 1 was developed:

[0022] Table 1 Gradient heating curve

[0023]

[0024] Total baking cycle: 18 - 22 days (4 - 6 days shorter than the traditional process).

[0025] In the present invention, the functions of the raw materials of the biomass binder are as follows: The biomass binder of the present invention is made of lignosulfonate, nanocrystalline cellulose (NCC), bio-based epoxy crosslinker, and pyrolytic carbon precursor. Among them, lignosulfonate is water-soluble and provides thermoplasticity and a carbon skeleton as the main binding phase. During the kneading stage, lignosulfonate wraps the aggregate particles through thermoplasticity to form a continuous binding layer. When roasted, lignin is carbonized to form isotropic carbon, reducing the porosity of the anode. The nanocrystalline cellulose crystals bind to lignin and the hydroxyl groups on the surface of the aggregate through hydrogen bonds, enhancing the interfacial strength between the binder and the aggregate. After carbonization, the fiber morphology is retained, optimizing the microscopic conductive path of the anode. The epoxy groups in the bio-based epoxy crosslinker react with the phenolic hydroxyl groups of lignosulfonate to form a covalent crosslinking network, enhancing the green strength of the anode. The crosslinked structure decomposes orderly at high temperatures, reducing tar generation (residual ash < 1%). In addition, it is biodegradable, and the degradation rate is > 90% in the natural environment within 6 months. The sucrose coking fine powder of the pyrolytic carbon precursor fills the gaps between the aggregates, reducing the initial porosity of the green anode. It is transformed into amorphous carbon at high temperatures, bridging the petroleum coke particles, reducing the resistivity of the anode. At the same time, it provides heterogeneous nucleation sites for the carbonization of lignin, promoting the formation of a dense carbon layer.

[0026] Compared with the prior art, the present invention has three core advantages:

[0027] 1. By adopting the synergistic modification technology of renewable lignin (lignosulfonate) and nanocellulose (NCC), a continuous three-dimensional carbon network is formed after the binder is coked, enabling the compressive strength of the prebaked anode to be ≥ 55 Ma (more than 20% higher than the prior art), the resistivity to be about 50 μΩ·m (10 - 15% lower than the prior art), and the porosity to be approximately 2 - 5%.

[0028] 2. Through the coupling of the bio-based epoxy crosslinker and the gradient roasting process, harmful gas emissions are significantly reduced. The unit anode VOCs emissions are reduced from 0.8 kg / t to 0.2 kg / t, more than 70% lower than the prior art. PAHs (polycyclic aromatic hydrocarbons) are not detected, and the biomass raw material cost is reduced by about 35% compared with coal tar pitch.

[0029] 3. By optimizing the forming and roasting parameters, the production cycle is shortened to 22 - 27 days, 18% shorter than the prior art. The unit energy consumption of the product is approximately 320 kgce / t, a 22% decrease compared with the prior art, providing an efficient technical path for the green transformation of the electrolytic aluminum industry. Description of the Drawings

[0030] Figure 1 It is the process flow chart of the present invention. Detailed Embodiments

[0031] The following examples and drawings are used to illustrate the effects.

[0032] Example 1:

[0033] The raw material ratio (by weight) is: 18% biomass binder (50% lignosulfonate + 15% NCC + 5% bio-based epoxy crosslinker (cardanol glycidyl ether) + 30% sucrose coking micropowder), 82% aggregate (85% calcined petroleum coke + 15% waste baked anode fragments).

[0034] The preparation process is as follows with reference to Figure 1 , specifically as follows.

[0035] I. Raw material pretreatment

[0036] 1) Preparation of binder system:

[0037] Biomass binder: Ultrasonically disperse lignosulfonate and NCC in water at 60°C (power 800W, 30 min) to form a uniform colloid. Add cardanol glycidyl ether and sucrose coking micropowder, and stir and react at pH = 9 for 2 h to generate a three-dimensional network structure, thus obtaining the biomass binder for standby.

[0038] 2) Coal tar pitch: Medium-temperature coal tar pitch is selected.

[0039] 3) Aggregate pretreatment: Calcine the petroleum coke to 1300°C (volatile matter < 0.5%), crush and classify it and then proportion it; first coarsely crush the waste pre-baked anode by a jaw crusher, then finely crush it by a pair-roll crusher, crush and classify it and then proportion it. The specific proportioning of the two is as follows: 38% coarse particles with a particle size of 4 - 8 mm, 32% medium particles with a particle size of 1 - 4 mm, and 30% fine powder with a particle size of less than 1 mm, thus obtaining the aggregate.

[0040] II. Preparation process:

[0041] 1. Kneading process

[0042] Dry mixing stage: Preheat the aggregate to 155°C, rotate at 30 - 40 rpm, dry mix for 18 minutes, and heat up to 170°C to make the temperature of the aggregate uniform;

[0043] Wet mixing stage: Then add the liquid biomass binder (temperature 60 - 70°C, solid content 65%) to the preheated aggregate, knead for 5 - 10 minutes, and the final kneading temperature is 135°C;

[0044] 2. Molding process:

[0045] Vibratory molding: The vibration frequency is 50 Hz, the amplitude is 1.5 mm, and the vibration time is 2 - 3 minutes. The density of the green block formed is ≥ 1.50 g / cm 3 ;

[0046] Molding with pressure reinforcement: The molding pressure is 20 MPa, and the pressure is maintained for 3 - 5 minutes. The final density of the green block is ≥ 1.58 g / cm3 , allowable deviation ±0.03.

[0047] 3. Roasting:

[0048] The gradient heating curve is shown in Table 1, the peak temperature is 1150 °C, and the total cycle is 19 days.

[0049] Example 2:

[0050] Raw material ratio (by weight): 18% biomass binder (60% lignosulfonate + 20% NCC + 10% bio-based epoxy crosslinker (cardanol glycidyl ether) + 10% sucrose coking fine powder), 82% aggregate (89% calcined petroleum coke + 11% waste calcined powder).

[0051] Preparation process:

[0052] 1. Kneading process

[0053] Dry mixing stage: Preheat the aggregate to 140 °C, rotate at 30 - 40 rpm, dry mix for 15 minutes, and heat up to 170 - 180 °C to make the aggregate temperature uniform;

[0054] Wet mixing stage: Then add the liquid biomass binder (temperature 60 - 70 °C, solid content 80%) to the preheated aggregate in two portions, knead for 5 - 10 minutes, and the final kneading temperature is 135 °C;

[0055] 2. Molding process:

[0056] Vibration molding: Vibration frequency 50 Hz, amplitude 1.5 mm, vibration time 2 - 3 minutes, the density of the green block formed ≥1.50 g / cm 3 ;

[0057] Molding with pressure reinforcement: Molding pressure 18 MPa, pressure holding for 3 - 5 minutes, the final density of the green block ≥1.58 g / cm 3 , allowable deviation ±0.03.

[0058] 3. Roasting:

[0059] The gradient heating curve is shown in Table 1, the peak temperature is 1130 °C, and the total cycle is 18 days (the growth rate of graphite microcrystals is increased to 20 °C / h).

[0060] Example 3:

[0061] Raw material ratio: 12% biomass binder (55% lignosulfonate + 18% NCC + 8% bio-based epoxy crosslinker (cardanol glycidyl ether) + 19% sucrose coking fine powder), 4% coal tar pitch, 84% aggregate (100% calcined petroleum coke).

[0062] Preparation process:

[0063] 1. Kneading

[0064] Dry kneading stage: Preheat the aggregate to 170°C, rotate at 30 - 40 rpm, dry knead for 15 minutes, and heat up to 170°C to make the aggregate temperature uniform;

[0065] Wet kneading stage: Preheat the aggregate to 170°C, first add the liquid biomass binder (temperature 60 - 70°C, solid content 73%), knead for 8 minutes, then add molten coal tar pitch and knead for 12 minutes, final temperature 150°C;

[0066] 2. Molding

[0067] Vibration molding: Vibration frequency 50 Hz, amplitude 1.5 mm, vibration time 2 - 3 minutes, the density of the green block formed ≥ 1.50 g / cm 3 ;

[0068] Molding with pressure reinforcement: Molding pressure 25 MPa, pressure holding for 3 - 5 minutes, the final density of the green block ≥ 1.58 g / cm 3 , allowable deviation ±0.03.

[0069] 3. Baking

[0070] The gradient heating curve is shown in Table 1, peak temperature 1180°C, total cycle 20 days.

[0071] Example 4:

[0072] Raw material ratio: 8% biomass binder (60% lignosulfonic acid + 12% NCC + 6% bio - based epoxy cross - linker (cardanol glycidyl ether) + 22% sucrose coking fine powder), 8% coal tar pitch, 84% aggregate (95% calcined petroleum coke + 5% waste calcined coke).

[0073] Preparation process:

[0074] 1. Kneading

[0075] Dry kneading stage: Preheat the aggregate to 170°C, rotate at 30 - 40 rpm, dry knead for 15 minutes, and heat up to 180°C to make the aggregate temperature uniform;

[0076] Wet kneading stage: Preheat the aggregate to 180°C, add coal tar pitch and liquid biomass binder (temperature 60 - 70°C, solid content 72%) simultaneously, knead for 22 minutes, final temperature 155°C;

[0077] 2. Molding

[0078] Vibration molding: Vibration frequency 50 Hz, amplitude 1.5 mm, vibration time 2 - 3 minutes, the density of the green block formed ≥ 1.50 g / cm 3 ;

[0079] Molding and strengthening: Molding pressure is 28 MPa, pressure holding time is 3 - 5 minutes, and the density of the final green block is ≥1.58 g / cm 3 , with an allowable deviation of ±0.03.

[0080] 3. Roasting

[0081] The gradient heating curve is shown in Table 1, the peak temperature is 1200 °C, and the total cycle is 21 days.

[0082] Example 5:

[0083] Raw material ratio: 9% biomass binder (20% NCC + 40% lignosulfonate + 10% bio - based epoxy cross - linker (cardanol glycidyl ether) + 30% sucrose coking fine powder), 6% coal tar pitch, 85% aggregate (100% calcined petroleum coke).

[0084] Preparation process:

[0085] 1. Kneading

[0086] Dry kneading stage: Preheat the aggregate to 138 °C, rotation speed is 30 - 40 rpm, dry knead for 15 minutes, then heat up to 170 °C to make the temperature of the aggregate uniform;

[0087] Wet kneading stage: Preheat the aggregate to 170 °C, first add the liquid biomass binder (temperature 60 - 70 °C, solid content 60%). After the binder is pre - dispersed, add it in three batches, knead for 14 minutes, then add the molten coal tar pitch and knead for 10 minutes, and the final temperature is 150 °C;

[0088] 2. Molding

[0089] Vibration molding: Vibration frequency is 50 Hz, amplitude is 1.5 mm, vibration time is 2 - 3 minutes, and the density of the green block made is ≥1.50 g / cm 3 ;

[0090] Molding and strengthening: Molding pressure is 16 MPa, pressure holding time is 3 - 5 minutes, and the density of the final green block is ≥1.58 g / cm 3 , with an allowable deviation of ±0.03.

[0091] 3. Roasting

[0092] The gradient heating curve is shown in Table 1, the peak temperature is 1100 °C, and the total cycle is 18 days.

[0093] According to "YST63.7 - 2006 Testing Methods for Carbon Materials for Aluminium - Part 7: Determination of Apparent Density - Dimension Method",

[0094] "YST63.9 - 2012 Testing Methods for Carbon Materials for Aluminium - Part 9: Determination of True Density - Helium Pycnometer Method",

[0095] "Test Methods for Carbon Materials for Aluminium - Part 11: Determination of Air Reactivity - Mass Loss Method (YST 63.11 - 2006)",

[0096] "Test Methods for Carbon Materials for Aluminium - Part 12: Determination of CO2 Reactivity of Pre - baked Anodes - Mass Loss Method (YST 63.12 - 2006)", "Test Methods for Carbon Materials for Aluminium - Part 19: Determination of Ash Content (YST 63.19 - 2021)", "Test Methods for Calcined Petroleum Coke for Carbon Anodes - Part 6: Determination of Powder Resistivity (YST 587.6 - 2006)", "Test Methods for Carbon Materials for Aluminium - Part 14: Determination of Flexural Strength - Three - Point Method (YS T 63.14 - 2023)", "Test Methods for Carbon Materials for Aluminium - Part 15: Determination of Compressive Strength (YS T 63.15 - 2023). Five examples were tested, and the test index data are shown in Table 2.",

[0097] Table 2 Test Index Data of Examples

[0098]

Claims

1. A green preparation method for low-carbon prebaked anode based on a biomass composite bonding system, characterized in that: The prebaked anode is prepared by mixing, kneading, molding and high-temperature calcining with aggregate and biomass binder as main raw materials; the raw materials and weight ratio of the prebaked anode are: biomass binder 6%-18%, coal tar pitch 0%-8%, aggregate 82%-86%; The biomass binder is prepared from 40-60% of lignin sulfonate, 10-20% of nanocellulose crystals, 5-10% of bio-based epoxy crosslinking agent and 10-30% of pyrolytic carbon precursor.

2. The method for preparing a low-carbon prebaked anode green material according to claim 1, characterized in that: The bio-based epoxy cross-linking agent is cardanol glycidyl ether; and the pyrolytic carbon precursor is sucrose coking powder.

3. The method for preparing a green low-carbon prebaked anode according to claim 1, characterized in that: The lignin sulfonate has a molecular weight of 5000-8000Da and a pH of 8-10; The nanocellulose crystals have a crystallinity of ≥80%, a diameter of 20-50 nm, and an aspect ratio of >50.

4. The method for preparing a green low-carbon prebaked anode according to claim 2, characterized in that: The preparation method of the biomass binder is as follows: lignin sulfonate and nanocellulose crystals are ultrasonically dispersed in 50-70°C water to form a uniform colloid, a bio-based epoxy crosslinking agent and a pyrolytic carbon precursor are added, and the mixture is stirred and reacted for 1-3 hours at pH=8-10 to generate a three-dimensional network structure to obtain the biomass binder.

5. The method for preparing a green low-carbon prebaked anode according to claim 1, characterized in that: The coal tar pitch is medium-temperature asphalt.

6. The method for preparing a green low-carbon prebaked anode according to claim 1, characterized in that: The aggregate system consists of 85%-100% calcined petroleum coke and 0-15% waste coke.

7. The method for preparing a low-carbon prebaked anode green material according to claim 6, characterized in that: The calcined petroleum coke is prepared by calcining petroleum coke to 1250-1350°C, crushing and grading it, and then mixing it into other materials. The method for making the waste cooked coke is as follows: the waste prebaked anode is firstly crushed by a jaw crusher, and then finely crushed by a double-roll crusher, and then mixed into other materials after crushing and grading.

8. The method for preparing a green low-carbon prebaked anode according to claim 7, characterized in that: The calcined petroleum coke and waste crushed aggregate are mixed together, specifically as follows: 35%-40% of coarse particles with a particle size of 4-8mm, 30-35% of medium particles with a particle size of 1-4mm, and 25-30% of fine powder with a particle size of less than 1mm.

9. The method for preparing a low-carbon prebaked anode green material according to any one of claims 1 to 8, characterized in that: The following steps are involved: 1) Mixing Dry mixing stage: preheat the aggregate to 135-170℃, dry mix for 15-20 minutes, and then heat it to 170-180℃ to make the aggregate temperature uniform; Wet mixing stage: first add liquid biomass binder with a solid content of 60%-80% to the aggregate, knead for 5-10 minutes, and the final kneading temperature is 135-140℃ to prevent thermal degradation of biomass; if coal tar is contained, heat the aggregate to 170-180℃, then add biomass binder and coal tar, knead for 8-25 minutes, and the final kneading temperature is 150-155℃; 2) Molding Vibration molding: vibration frequency 45-50Hz, amplitude 1.2-1.8mm, vibration time 2-3 minutes, the density of the green block is ≥1.50g / cm 3 ; Molding strengthening: Molding pressure 15-30MPa, holding pressure 3-5 minutes, final green block density ≥1.58g / cm 3 ; 3) Calcination The roasting curve adopts a gradient heating curve, which is as follows:

10. The method for preparing a green low-carbon prebaked anode according to claim 9, characterized in that: The total roasting period is 18-22 days.

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