Method for determining proportioning of resource utilization of cathode overhaul slag of electrolytic aluminum cell

Abstract

The application discloses a kind of electrolytic aluminum cell cathode overhaul slag resource utilization proportioning determination method, by analyzing the calorific value and composition of cathode overhaul slag, the concentration of main pollutants therein is determined, the composition of raw coal is determined, the minimum calorific value of power plant coal, the migration and conversion law of fluorine element in coal-fired boiler and the fluorine element balance point are determined to determine the blending ratio of cathode overhaul slag and raw coal.The blending ratio of cathode overhaul slag and raw coal determined by the method of the application is incinerated, no secondary pollution and new hazardous waste will be produced, the method of the application can comprehensively utilize the heat resources of cathode overhaul slag, the process is simple, the energy consumption is low, the recovery efficiency of cathode overhaul slag is high, and harmless, reduction and resource utilization can be achieved, the secondary risk brought by cathode overhaul slag disposal is reduced.It opens up a new direction and idea for the resource utilization and reduction of cathode overhaul slag in the national electrolytic aluminum industry, and the economic, environmental and social benefits are very significant.

Description

Technical Field

[0001] This invention relates to the field of solid waste treatment technology for electrolytic aluminum, specifically to a method for determining the proportion of slag from the cathode overhaul of an electrolytic aluminum cell for resource utilization. Background Technology

[0002] Cathode overhaul slag is an unavoidable and continuously increasing solid waste from the aluminum electrolysis industry. Its main components include valuable elements such as carbon and cryolite, as well as approximately one-third fluoride, 0.2%–1% cyanide, and small amounts of impurities such as AlN, Al4C3, and aluminosilicates. It has become the second largest solid waste in the aluminum industry after red mud. The soluble fluoride and cyanide content in aluminum electrolysis cathode overhaul slag is as high as 2000–6000 g / L and 10–40 mg / L, respectively, exhibiting significant leaching toxicity and easily causing pollution of soil, surface water, and groundwater. It also releases toxic gases (NH3, HCN, CH4), causing flue gas pollution. Studies have shown that untreated cathode overhaul slag disrupts the agricultural ecological balance, pollutes natural water bodies, and harms plant and animal growth and human health. Therefore, aluminum electrolysis cathode overhaul slag has become one of the major environmental pollution sources in the aluminum electrolysis industry and has been explicitly listed as a hazardous industrial solid waste by many countries. Failure to treat it will severely pollute the environment.

[0003] Currently, the main technologies for treating cathode overhaul slag include lime leaching, alkaline leaching, combustion, electric arc furnace production of high-purity carbon particles, flotation-chemical treatment, landfill disposal, and indefinite storage. Landfill disposal and indefinite storage are currently the preferred options for disposing of cathode overhaul slag, but they have high operating costs and cause significant environmental pollution. Combustion treatment of cathode overhaul slag does not effectively utilize the carbon in hazardous waste, resulting in low resource utilization. Due to the extremely high fluorine content of cathode overhaul slag, the fluoride concentration in the leachate far exceeds the standard, making it a major hazardous solid waste in the aluminum electrolysis industry. From a technical perspective, both pyrometallurgical and hydrometallurgical treatments of cathode overhaul slag achieve harmlessness and meet national technical requirements. From an energy use perspective, both pyrometallurgical and hydrometallurgical treatments increase energy consumption. From a resource utilization perspective, both pyrometallurgical and hydrometallurgical treatments of cathode overhaul slag have low resource utilization efficiency, and the carbon content in the flotation products of hydrometallurgical treatment can reach up to 85%, which cannot meet the requirements for industrial use, necessitating further optimization and purification process research. Furthermore, the waste generated after pyrometallurgical and hydrometallurgical treatments remains hazardous solid waste, requiring significant land area and incurring high further treatment costs. Currently, there are no feasible methods or processes to achieve the reduction and resource utilization of anode carbon slag and cathode overhaul slag. However, because these carbonaceous solid wastes, such as cathode overhaul slag, contain harmful components like fluorides, improper co-firing can lead to excessive fluoride levels in flue gas and solid waste from coal-fired power plants, altering the properties of these solid wastes, causing environmental pollution, and increasing enterprise management and operating costs. Therefore, the rational selection of hazardous waste treatment processes for electrolytic aluminum and the continuous development of new treatment technologies are crucial guarantees for promoting the sustainable development of the electrolytic aluminum industry.

[0004] Therefore, there is an urgent need for those skilled in the art to provide a method for determining the resource utilization ratio of cathode overhaul slag in electrolytic aluminum electrolytic cells that is simple in process, low in energy consumption, can achieve harmlessness, volume reduction and resource utilization, reduce the secondary risks brought about by cathode overhaul slag disposal, and has a high recovery rate. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for determining the proportion of slag used for resource utilization in the cathode overhaul of aluminum electrolytic cells. This method solves the problems of complex processes, high energy consumption, and low recovery rates in existing technologies.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a method for determining the proportion of slag from the cathode overhaul of an aluminum electrolytic cell for resource utilization, which specifically includes the following steps:

[0008] S1: Analyze the calorific value and composition of the cathode overhaul slag to be mixed, and determine the concentration of the main pollutants;

[0009] S2: Determine the composition of raw coal and the concentration of major pollutants;

[0010] S3: Determine the minimum calorific value requirements for coal used in power plants, and determine the migration and transformation law of fluorine in coal-fired boilers and the fluorine equilibrium point based on actual co-firing experiments;

[0011] S4: Determine the proportion of fluoride content in the output end relative to the total fluoride content in the input end. The output end includes fly ash, slag, gypsum slag, and flue gas. The proportions of fluoride content in the fly ash, slag, gypsum slag, and flue gas relative to the total fluoride content in the input end are as follows: fly ash 10-15%, slag 0.1-0.5%, gypsum slag 80-85%, and flue gas 0.01-0.1%.

[0012] S5: Based on the actual co-firing experimental data, the migration and transformation law of fluorine in the coal-fired boiler in step S3 and the fluorine equilibrium point, the transfer content of fluorides in each component in step S4, and the concentration of major pollutants in the cathode overhaul slag and raw coal in steps S1 and S2, the blending ratio of cathode overhaul slag and raw coal is calculated and determined.

[0013] S6: Blending. The cathode overhaul slag is transported by hazardous waste transport vehicles to the crushing and ball milling workshop. The cathode overhaul slag is crushed into particles with a diameter of less than 10mm by a crusher and a ball mill. Then, it is conveyed to the coal mill by a transmission device. The crushed cathode overhaul slag is mixed with raw coal according to the blending ratio of cathode overhaul slag and raw coal in step S5. After mixing, it is ground evenly in the coal mill and then conveyed to the coal feeding bin by a coal feeder. Finally, it enters the boiler for combustion and power generation.

[0014] Furthermore, the main pollutants in step S1 are fluorides, cyanides, etc.

[0015] Furthermore, in step S4, the input end consists of cathode overhaul slag and raw coal, and the total fluoride at the input end includes the total fluoride content of the cathode overhaul slag and raw coal.

[0016] Furthermore, in step S4, the fluoride leaching emission concentration in the fly ash, slag, and gypsum slag at the output end is ≤100 mg / L; the fluoride leaching emission concentration in the flue gas is ≤3.0 mg / m³. 3 .

[0017] Furthermore, the total fluoride content at the input end in step S4 is determined based on the maximum emission limit of fluoride in flue gas, as follows:

[0018] Maximum emission limit of fluoride in flue gas C × flue gas emission / fluoride content in flue gas as a percentage of fluoride content at the input end = total fluoride amount at the input end.

[0019] Furthermore, the calculation basis for the blending ratio of cathode overhaul slag and raw coal in step S5 is as follows:

[0020] Raw coal mass × total fluoride concentration of raw coal + cathode overhaul slag mass × total fluoride concentration of cathode overhaul slag ≈ fly ash mass × total fluoride concentration of fly ash + slag mass × total fluoride concentration of slag + gypsum slag mass × total fluoride concentration of gypsum slag + flue gas volume × fluoride concentration in flue gas.

[0021] Furthermore, in step S5, the blending ratio of cathode overhaul slag to raw coal is 1.4%-6.0%.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] This invention, through analysis of the main components, calorific value, and raw coal composition of cathode overhaul slag, reveals that the slag has a high carbon content and a high calorific value, making it valuable for resource utilization through co-firing with coal. Using the co-firing ratio of cathode overhaul slag to raw coal determined by the method of this invention for incineration power generation, no secondary pollution or new hazardous waste is generated during the incineration process. This invention's method enables comprehensive utilization of the thermal resources of cathode overhaul slag, is simple in process, low in energy consumption, and achieves high recovery efficiency. It also achieves harmlessness, volume reduction, and resource utilization, reducing the secondary risks associated with cathode overhaul slag disposal. Attached Figure Description

[0024] Figure 1 This is a graph showing the migration pattern of fluorides when the ratio of cathode overhaul slag to raw coal is 1.4%.

[0025] Figure 2 The daily variation curve of fluoride leaching concentration in fly ash when the ratio of cathode overhaul slag to raw coal is 1.4% is shown.

[0026] Figure 3 The daily variation curve of fluoride leaching concentration in slag when the ratio of cathode overhaul slag to raw coal is 1.4% is shown.

[0027] Figure 4 The daily variation curve of fluoride leaching concentration in gypsum slag when the ratio of cathode overhaul slag to raw coal is 1.4% is shown.

[0028] Figure 5 This is the daily variation curve of fluoride leaching concentration in flue gas when the ratio of cathode overhaul slag to raw coal is 1.4%.

[0029] Figure 6 This is the daily variation curve of fluoride leaching concentration in fly ash when the ratio of cathode overhaul slag to raw coal is 6%.

[0030] Figure 7 This is the daily variation curve of fluoride leaching concentration in the slag when the ratio of cathode overhaul slag to raw coal is 6%.

[0031] Figure 8This is the daily variation curve of fluoride leaching concentration in gypsum slag when the ratio of cathode overhaul slag to raw coal is 6%.

[0032] Figure 9 This is the daily variation curve of fluoride leaching concentration in flue gas when the ratio of cathode overhaul slag to raw coal is 6%.

[0033] Figure 10 The curves show the daily variation of fluoride leaching concentrations in fly ash, slag, and gypsum slag when the ratio of cathode overhaul slag to raw coal is 5%. Detailed Implementation

[0034] To make the objectives and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention. Example 1

[0035] This embodiment of a method for determining the proportion of slag used for resource utilization in the cathode overhaul of an aluminum electrolytic cell includes the following steps:

[0036] S1: Analyze the calorific value and composition of the cathode overhaul slag to be mixed, and determine the concentration of major pollutants such as fluoride and cyanide.

[0037] S2: Determine the composition of raw coal and the concentration of major pollutants;

[0038] S3: Determine the minimum calorific value requirements for coal used in power plants, the migration and transformation patterns of fluorine in coal-fired boilers, and the fluorine equilibrium point. In this embodiment, the migration and transformation patterns of fluorine were tested after co-firing, and the test results are attached. Figure 1 ;

[0039] S4: From Appendix Figure 1 It can be seen that the proportion of fluoride content in each output end to the total fluoride content in the input end is as follows: fly ash 13.8%, slag 0.32%, gypsum slag 83.61%, and flue gas 0.05%. The total fluoride content in the input end is determined based on the maximum emission limit of fluoride in flue gas, according to the formula: C × flue gas emission / flue gas fluoride content as a percentage of input end fluoride content = total fluoride content in the input end. Since the calorific value of waste cathode overhaul slag is comparable to that of coal, the calorific value factor of blending is not necessary; only the concentration of fluoride in the flue gas emission after coal combustion needs to be considered.

[0040] S5: Based on actual co-firing experimental data, the migration and transformation law of fluorine in the coal-fired boiler in step S3 and the fluorine equilibrium point, the transfer content of fluorides in each component in step S4, and the concentrations of major pollutants in the cathode overhaul slag and raw coal in steps S1 and S2, the blending ratio of cathode overhaul slag to raw coal is determined to be 1.4%. The concentration of fluorides in the raw coal accounts for 9.13% of the total fluorides at the input end, and the concentration of fluorides in the cathode overhaul slag accounts for 90.87% of the total fluorides at the input end. The calculation basis is as follows:

[0041] Raw coal mass × total fluoride concentration of raw coal + cathode overhaul slag mass × total fluoride concentration of cathode overhaul slag ≈ fly ash mass × total fluoride concentration of fly ash + slag mass × total fluoride concentration of slag + gypsum slag mass × total fluoride concentration of gypsum slag + flue gas volume × fluoride concentration in flue gas.

[0042] S6: Blending. The cathode overhaul slag with a blending ratio of 1.4% is transported by hazardous waste transport vehicles to the crushing and ball milling workshop. The cathode overhaul slag is crushed into particles with a particle size of less than 10mm by a crusher and a ball mill. Then, it is conveyed to the coal mill by a transmission device. The crushed cathode overhaul slag is mixed with raw coal according to the blending ratio of cathode overhaul slag and raw coal in step S5. After mixing, it is ground evenly in the coal mill and then conveyed to the coal feeding bin by a coal feeder. Finally, it enters the boiler for combustion and power generation. Example 2

[0043] This embodiment of a method for determining the proportion of slag used for resource utilization in the cathode overhaul of an aluminum electrolytic cell includes the following steps:

[0044] S1: Analyze the calorific value and composition of the cathode overhaul slag to be mixed, and determine the concentration of major pollutants such as fluoride and cyanide.

[0045] S2: Determine the composition of raw coal and the concentration of major pollutants;

[0046] S3: Determine the minimum calorific value requirements for coal used in power plants, the migration and transformation laws of fluorine in coal-fired boilers, and the fluorine equilibrium point;

[0047] S4: The proportion of fluoride content at each output end to the total fluoride content at the input end is as follows: fly ash 15%, slag 0.1%, gypsum slag 80%, and flue gas 0.1%; the total fluoride content at the input end is determined based on the maximum emission limit of fluoride in flue gas, according to the following formula: C × flue gas emission / flue gas fluoride content as a percentage of input end fluoride content = total fluoride amount at the input end;

[0048] S5: Based on actual co-firing experimental data, the migration and transformation law of fluorine in the coal-fired boiler in step S3 and the fluorine equilibrium point, the transfer content of fluorides in each component in step S4, and the concentration of major pollutants in the cathode overhaul slag and raw coal in steps S1 and S2, the blending ratio of cathode overhaul slag to raw coal is determined to be 6%. The calculation basis is as follows:

[0049] Raw coal mass × total fluoride concentration of raw coal + cathode overhaul slag mass × total fluoride concentration of cathode overhaul slag ≈ fly ash mass × total fluoride concentration of fly ash + slag mass × total fluoride concentration of slag + gypsum slag mass × total fluoride concentration of gypsum slag + flue gas volume × fluoride concentration in flue gas.

[0050] S6: Blending. The cathode overhaul slag with a blending ratio of 6% is transported by hazardous waste transport vehicles to the crushing and ball milling workshop. The cathode overhaul slag is crushed into particles with a particle size of less than 10mm by a crusher and a ball mill. Then, it is conveyed to the coal mill by a transmission device. The crushed cathode overhaul slag is mixed with raw coal according to the blending ratio of cathode overhaul slag and raw coal in step S5. After mixing, it is ground evenly in the coal mill and then conveyed to the coal feeding bin by a coal feeder. Finally, it enters the boiler for combustion and power generation. Example 3

[0051] This embodiment of a method for determining the proportion of slag used for resource utilization in the cathode overhaul of an aluminum electrolytic cell includes the following steps:

[0052] S1: Analyze the calorific value and composition of the cathode overhaul slag to be mixed, and determine the concentration of major pollutants such as fluoride and cyanide.

[0053] S2: Determine the composition of raw coal and the concentration of major pollutants;

[0054] S3: Determine the minimum calorific value requirements for coal used in power plants, the migration and transformation laws of fluorine in coal-fired boilers, and the fluorine equilibrium point;

[0055] S4: The proportion of fluoride content in each output end relative to the total fluoride content in the input end is as follows: fly ash 10%, slag 0.5%, gypsum slag 85%, and flue gas 0.01%. The total fluoride content in the input end is determined based on the maximum emission limit of fluoride in flue gas, calculated as: C × flue gas emission / flue gas fluoride content relative to the input end fluoride content = total fluoride content in the input end. In other specific embodiments, the proportion of fluoride content in each output end relative to the total fluoride content in the input end can also be: any proportion of 10-15% in fly ash, any proportion of 0.1-0.5% in slag, any proportion of 80-85% in gypsum slag, and any proportion of 0.01-0.1% in flue gas.

[0056] S5: Based on actual co-firing experimental data, the migration and transformation law of fluorine in the coal-fired boiler in step S3 and the fluorine equilibrium point, the transfer content of fluorides in each component in step S4, and the concentration of major pollutants in the cathode overhaul slag and raw coal in steps S1 and S2, the blending ratio of cathode overhaul slag to raw coal is calculated to be 5%. In other specific embodiments, the blending ratio of cathode overhaul slag to raw coal can also be any ratio between 1.4% and 6.0%, calculated based on the following:

[0057] Raw coal mass × total fluoride concentration of raw coal + cathode overhaul slag mass × total fluoride concentration of cathode overhaul slag ≈ fly ash mass × total fluoride concentration of fly ash + slag mass × total fluoride concentration of slag + gypsum slag mass × total fluoride concentration of gypsum slag + flue gas volume × fluoride concentration in flue gas.

[0058] S6: Blending. The cathode overhaul slag with a blending ratio of 5% is transported by hazardous waste transport vehicles to the crushing and ball milling workshop. The cathode overhaul slag is crushed into particles with a particle size of less than 10mm by a crusher and a ball mill. Then, it is conveyed to the coal mill by a transmission device. The crushed cathode overhaul slag is mixed with raw coal according to the blending ratio of cathode overhaul slag to raw coal in step S5. After mixing, it is ground evenly in the coal mill and then conveyed to the coal feeding bin by a coal feeder. Then, it enters the boiler for combustion and power generation. Blending is carried out continuously for 10 days.

[0059] Since there are certain differences between actual experimental values ​​and theoretical calculation values, and the blending ratio is affected by the production process, it is necessary to conduct a blending experiment based on theoretical calculations to obtain the actual migration and transformation law of fluorides, and then determine the actual blending ratio of cathode overhaul slag based on theoretical calculations and experimental values.

[0060] Comparative Example

[0061] The raw coal, which is not mixed with cathode overhaul slag, is ground evenly in a coal mill, then transported to the coal feeding bin by a coal feeder, and then enters the boiler for combustion and power generation.

[0062] To determine the optimal co-firing ratio in the above embodiments that ensures both the normal operation of the power plant and the resource utilization of cathode overhaul slag without causing secondary pollution, solid waste fly ash, slag, gypsum slag, and flue gas from the boiler combustion power generation process in Examples 1-3 and the comparative examples were collected daily to detect changes in fluoride concentration. The methods specified in the "Emission Standard of Pollutants for Flue Gas from Thermal Power Plants" (GB 13223-2011) and the "Emission Standard of Pollutants for Aluminum Industry" (GB 25465-2010) were used for detection, and curve changes were plotted.

[0063] When the ratio of cathode overhaul slag to raw coal is 1.4%, refer to the appendix. Figure 2-5It can be seen that the maximum detectable concentration of fluoride leaching in fly ash is 11.7176 mg / L, in slag it is 1.8018 mg / L, in gypsum slag it is 4.0034 mg / L, and in flue gas it is 1.86 mg / m³. When the ratio of cathode overhaul slag to raw coal is 6%, refer to the appendix. Figure 6-9 It was found that the maximum detectable concentration of fluoride leaching in fly ash was 11.51 mg / L, in slag it was 3.45 mg / L, in gypsum slag it was 4.19 mg / L, and in flue gas it was 0.725 mg / m³. (See attached image.) Figure 10 The graph shows the daily average fluoride leaching concentration changes of fly ash, slag, and gypsum slag. (See attached graph.) Figure 10 When the ratio of cathode overhaul slag to raw coal is 5%, as shown in the figure, the fluoride leaching concentration of fly ash is much higher than that of slag and gypsum slag. The average fluoride leaching concentration during the co-firing experiment was 33.42 mg / L, and the fluoride leaching concentration of slag leachate was below 10 mg / L during the co-firing experiment. The fluoride leaching concentration of gypsum slag fluctuated less. In the continuous co-firing experiment of Example 3, the fluoride in the flue gas was monitored on days 6, 7, 8, and 9. The daily average concentration change of fluoride in the atmosphere is shown in the table below. As can be seen from the table, the fluoride concentration in the flue gas was less than 0.2 mg / m³.

[0064]

[0065] Therefore, the fluoride leaching concentrations in all solid wastes are lower than the 100 mg / L limit for fluoride leaching emissions specified in the "Identification Standard for Hazardous Waste: Leaching Toxicity Identification" (GB 5085.3-2019). The fluoride concentration in the flue gas fully complies with the requirements of the 3.0 mg / m³ fluoride emission concentration specified in the "Emission Standard of Pollutants for Aluminum Industry" (GB 25465-2010) and the 30 μg / m³ limit for mercury and its compounds specified in the "Emission Standard of Pollutants for Flue Gas from Thermal Power Plants" (GB 13223-2011).

[0066] In summary, this invention, through analysis of the main components, calorific value, and raw coal composition of cathode overhaul slag, reveals that the slag has a high carbon content and a high calorific value, making it valuable for resource utilization through co-firing with coal. Using the co-firing ratio of cathode overhaul slag to raw coal determined by the method of this invention for incineration power generation will not generate secondary pollution or new hazardous waste during the incineration process. The co-firing ratio of cathode overhaul slag to raw coal determined by the method of this invention enables comprehensive utilization of the thermal resources of cathode overhaul slag, with a simple process, low energy consumption, high recovery efficiency, and achieves harmlessness, volume reduction, and resource utilization, reducing the secondary risks associated with cathode overhaul slag disposal. This opens up new directions and ideas for the resource utilization and volume reduction of cathode overhaul slag in the national electrolytic aluminum industry, with significant economic, environmental, and social benefits.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for determining the proportion of residue from the cathode overhaul of an aluminum electrolytic cell for resource utilization, characterized in that: Includes the following steps: S1: Analyze the composition of the cathode overhaul slag to be mixed and determine the concentration of fluorides in it; S2: Determine the composition of raw coal and the concentration of fluorides therein; S3: Determine the minimum calorific value of coal used in power plants, the migration and transformation laws of fluorine in coal-fired boilers, and the fluorine equilibrium point; S4: Determine the proportion of fluoride content in the output end relative to the total fluoride content in the input end. The output end includes fly ash, slag, gypsum slag, and flue gas. The proportions of fluoride content in the fly ash, slag, gypsum slag, and flue gas relative to the total fluoride content in the input end are as follows: fly ash 10-15%, slag 0.1-0.5%, gypsum slag 80-85%, and flue gas 0.01-0.1%. The input end consists of cathode overhaul slag and raw coal, and the total fluoride at the input end includes the total fluoride content of the cathode overhaul slag and raw coal; The total fluoride content at the input end is determined based on the maximum emission limit for fluoride in flue gas, as follows: Maximum emission limit of fluoride in flue gas × flue gas emission / fluoride content in flue gas as a percentage of fluoride content at the input end = total fluoride amount at the input end; The leaching discharge concentration of fluorides in the output end fly ash, slag, and gypsum slag is ≤100 mg / L; the leaching discharge concentration of fluorides in the flue gas is ≤3.0 mg / m 3 ; S5: Based on the co-firing experiment data, the migration and transformation law of fluorine in the coal-fired boiler in step S3 and the fluorine equilibrium point, the transfer content of fluorides in each component in step S4, and the fluoride concentration in cathode overhaul slag and raw coal in steps S1 and S2, the blending ratio of cathode overhaul slag and raw coal is calculated and determined. The calculation basis for the blending ratio of cathode overhaul slag and raw coal is as follows: Raw coal mass × total fluoride concentration of raw coal + cathode overhaul slag mass × total fluoride concentration of cathode overhaul slag ≈ fly ash mass × total fluoride concentration of fly ash + slag mass × total fluoride concentration of slag + gypsum slag mass × total fluoride concentration of gypsum slag + flue gas volume × fluoride concentration in flue gas. S6: Blending. The cathode overhaul slag is crushed into particles with a diameter of less than 10mm using a crusher and ball mill. The crushed cathode overhaul slag is then mixed with raw coal according to the blending ratio in step S5. After mixing, the mixture is ground evenly in a coal mill and then fed into the boiler for combustion and power generation.

2. The method for determining the proportion of cathode overhaul slag for resource utilization in an electrolytic aluminum cell according to claim 1, characterized in that: In step S5, the blending ratio of cathode overhaul slag to raw coal is 1.4%-6.0%.

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