CN-122007116-A - Resource utilization method of carbon slag in aluminum electrolysis cell

CN122007116ACN 122007116 ACN122007116 ACN 122007116ACN-122007116-A

Abstract

The invention provides a resource utilization method of carbon slag in an aluminum electrolysis cell, and relates to the technical field of solid waste resource utilization. A method for recycling carbon slag in an aluminum electrolysis cell comprises the following steps of S1, crushing, screening and drying the carbon slag in the aluminum electrolysis cell, detecting components to obtain a dried material, S2, weighing the dried material and sodium carbonate, mixing to form a mixture, placing the mixture into a graphite crucible, paving a layer of stone tar to prevent flame, placing the mixture into a box-type resistance furnace, heating to react, and cooling to obtain mixed slag, and S3, mixing the mixed slag with deionized water. The deep extraction and efficient utilization of valuable elements such as fluorine, sodium, aluminum and carbon are realized by constructing a green process route of 'reduction-harmless-high-valued' of the aluminum electrolysis cell carbon slag, the resource recovery rate is remarkably improved, and the valuable elements such as fluorine, sodium, aluminum and carbon in the aluminum electrolysis cell carbon slag can be effectively recovered, so that the recycling of resources is realized.

Inventors

YAO LI
WEI DONGDONG
YAN KAI
PAN RUI
LIAO XIN
PAN LONGHUI
HUANG JIE
ZHANG HUI

Assignees

江西飞宇新能源科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260214

Claims (10)

1. A method for recycling carbon slag in an aluminum electrolysis cell is characterized by comprising the following steps: Step S1, crushing, screening and placing aluminum electrolysis cell carbon residues in an oven for drying, and detecting components to obtain a dried material; Step S2, weighing a dry material and sodium carbonate, mixing the dry material and the sodium carbonate to form a mixture, putting the mixture into a graphite crucible, paving a layer of stone tar for flame retardance, putting the mixture into a box-type resistance furnace, heating the mixture for reaction, and cooling the mixture to obtain mixed slag; Step S3, mixing the mixed slag with deionized water, adding sulfuric acid to adjust the pH value to 1-3, placing the mixture in a water bath kettle for constant-temperature reaction, performing solid-liquid separation to obtain filter residue A and filtrate A, washing the filter residue A with water, and drying to obtain carbon powder; Step S4, adding sodium hydroxide into the filtrate A, adjusting the pH to 5.5-6.5, placing the mixture in a water bath kettle for constant-temperature reaction, and filtering to obtain filter residue B and filtrate B; step S5, weighing filter residue B, mixing the filter residue B with water, washing the mixture for 3 times to remove residual sodium salt, washing the mixture, drying the mixture by washing the mixture, transferring the dried mixture into a muffle furnace for calcination treatment, and cooling the dried mixture to obtain aluminum fluoride solid; and S6, transferring the filtrate B into an evaporation dish for evaporation crystallization, filtering and separating crystals, and further dehydrating in an oven to obtain anhydrous sodium sulfate.
2. The method for recycling carbon residue in aluminum electrolysis cell according to claim 1, wherein a jaw crusher is adopted in the crushing treatment in the step S1.
3. The method for recycling carbon residue in an aluminum electrolysis cell according to claim 1, wherein the screening in the step S1 is performed by a 150-200 mesh screen.
4. The method for recycling carbon residue in an aluminum electrolysis cell according to claim 1, wherein the mass ratio of the drying material to the sodium carbonate in the step S2 is 1:1.5-2.5.
5. The method for recycling carbon residue in an aluminum electrolysis cell according to claim 1, wherein the reaction temperature is 650-750 ℃ and the reaction time is 2-4 h during the heating reaction in the step S2.
6. The method for recycling carbon residue in an aluminum electrolysis cell according to claim 1, wherein the reaction temperature of the constant-temperature reaction in the step S3 is 70-80 ℃ and the reaction time is 2-3 h.
7. The method for recycling carbon residue in an aluminum electrolysis cell according to claim 1, wherein the reaction temperature of the constant-temperature reaction in the step S4 is 70-80 ℃ and the reaction time is 2-4 hours.
8. The method for recycling carbon residue in an aluminum electrolysis cell according to claim 1, wherein the filter residue B in the step S5 is mixed with water according to a solid-to-liquid ratio of 1:3-4.
9. The method for recycling carbon residue in an aluminum electrolysis cell according to claim 1, wherein the temperature of the calcination treatment in the step S5 is 450-550 ℃ and the calcination time is 3-7 h.
10. The method for recycling carbon residue in aluminum electrolysis cell according to claim 1, wherein the temperature of the evaporative crystallization in the step S6 is 70-80 ℃.

Description

Resource utilization method of carbon slag in aluminum electrolysis cell Technical Field The invention relates to the technical field of solid waste resource utilization, in particular to a resource utilization method of carbon residues in an aluminum electrolysis cell. Background The carbon slag of aluminium electrolytic bath is a dangerous waste produced in the aluminium industrial production process, and its composition is complex, and contains a large quantity of electrolyte (such as cryolite and sub cryolite), alumina and carbon material. The traditional treatment mode mainly comprises piling, so that electrolyte resource waste is caused, and the problem of environmental pollution is also caused. Therefore, the method has important significance on environmental protection for the resource utilization of the carbon slag of the aluminum electrolysis cell, In the traditional method, a flotation treatment process is mainly adopted, and during treatment, the flotation method has the problem of incomplete carbon-electricity separation, the direct roasting method is easy to produce secondary pollution, and how to effectively separate carbon-electricity components so as to improve the recycling utilization of the carbon slag of the aluminum electrolysis cell is to be further researched. Therefore, it is necessary to provide a method for recycling carbon residue in an aluminum electrolysis cell to solve the above technical problems. Disclosure of Invention The invention provides a resource utilization method of carbon residue in an aluminum electrolysis cell, which solves the problem of how to effectively separate carbon and electricity components in the related technology so as to improve the resource utilization of the carbon residue of the aluminum electrolysis cell to be further researched. In order to solve the technical problems, the method for recycling the carbon residue in the aluminum electrolysis cell provided by the invention comprises the following steps: Step S1, crushing, screening and placing aluminum electrolysis cell carbon residues in an oven for drying, and detecting components to obtain a dried material; Step S2, weighing a dry material and sodium carbonate, mixing the dry material and the sodium carbonate to form a mixture, putting the mixture into a graphite crucible, paving a layer of stone tar for flame retardance, putting the mixture into a box-type resistance furnace, heating the mixture for reaction, and cooling the mixture to obtain mixed slag; Step S3, mixing the mixed slag with deionized water, adding sulfuric acid to adjust the pH value to 1-3, placing the mixture in a water bath kettle for constant-temperature reaction, performing solid-liquid separation to obtain filter residue A and filtrate A, washing the filter residue A with water, and drying to obtain carbon powder; Step S4, adding sodium hydroxide into the filtrate A, adjusting the pH to 5.5-6.5, placing the mixture in a water bath kettle for constant-temperature reaction, and filtering to obtain filter residue B and filtrate B; step S5, weighing filter residue B, mixing the filter residue B with water, washing the mixture for 3 times to remove residual sodium salt, washing the mixture, drying the mixture by washing the mixture, transferring the dried mixture into a muffle furnace for calcination treatment, and cooling the dried mixture to obtain aluminum fluoride solid; and S6, transferring the filtrate B into an evaporation dish for evaporation crystallization, filtering and separating crystals, and further dehydrating in an oven to obtain anhydrous sodium sulfate. Preferably, a jaw crusher is used for the crushing treatment in the step S1. Preferably, in the step S1, screening is performed by a 150-200 mesh screen. Preferably, in the step S2, the mass ratio of the drying material to the sodium carbonate is 1:1.5-2.5. Preferably, in the step S2, the reaction temperature is 650-750 ℃ and the reaction time is 2-4 hours. Preferably, the reaction temperature of the constant-temperature reaction in the step S3 is 70-80 ℃ and the reaction time is 2-3 h. Preferably, the reaction temperature of the constant-temperature reaction in the step S4 is 70-80 ℃ and the reaction time is 2-4 hours. Preferably, in the step S5, the filter residue B and water are mixed according to a solid-liquid ratio of 1:3-4. Preferably, the temperature of the calcination treatment in the step S5 is 450-550 ℃, and the calcination time is 3-7 h. Preferably, the temperature of the evaporative crystallization in the step S6 is 70-80 ℃. Compared with the related technology, the method for recycling the carbon residue in the aluminum electrolysis cell has the following beneficial effects: The method realizes the directional conversion of electrolyte components by regulating and controlling the alkali melting temperature and the heat preservation time, adopts a multistage solid-liquid separation technology of alkali melting, acid leaching, alkali precipitation