Method for recycling aluminum electrolysis carbon residue

Abstract

The application discloses a method for recycling aluminum electrolysis carbon residue, and comprises the following steps: pretreatment: drying and grinding the aluminum electrolysis carbon residue to obtain a first material; activation: placing the first material in a tube furnace, and activating under the condition of heating by introducing a gas to obtain a second material; loading active components: mixing the second material with a salt solution of a third material, and filtering after heating and stirring to obtain a fourth material; the third material is one or a combination of Fe(NO3)3.9H2O, Fe(NO3)2, Cu(NO3)2, Zn(NO3)2 and Ni(NO3)2.6H2O; molding: adding a binder and a pore-forming agent to the fourth material, and obtaining a fifth material through extrusion molding; and heat treatment: placing the fifth material in a tube furnace, and obtaining a desulfurizer through heat treatment. The application realizes the treatment and utilization of hazardous waste resources by preparing the desulfurizer from the aluminum electrolysis carbon residue and the waste tar obtained by baking the anode and / or cathode for aluminum.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-ferrous metallurgy, in particular to a method for resource utilization of aluminum electrolysis carbon residue. BACKGROUND

[0002] In the actual production process of aluminum electrolysis, due to the quality of anode, process technical conditions and on-site operation quality, etc., it will lead to the production of anode carbon residue. According to statistics, about 5-15 kg of carbon residue is produced per ton of primary aluminum, and in 2017, the primary aluminum production in China was 3227 million tons, and the total carbon residue produced by aluminum electrolysis enterprises was about 290,000 tons. Carbon residue will harm the environment due to the presence of toxic substances such as fluorine, and was listed in the National Hazardous Waste List in 2016 (Code: 321-025-48, Hazardous Characteristics: T). According to the relevant policies of the state, carbon residue is prohibited from being discarded or stored in the open air, and is required to be disposed of harmlessly within the electrolytic aluminum enterprise or entrusted to a unit with relevant processing qualifications. Electrolytic aluminum enterprises are under pressure from high hazardous waste disposal fees and hazardous waste environmental protection taxes, so the harmless treatment and resource utilization technology of carbon residue is a difficult problem that needs to be solved in the electrolytic aluminum industry. At present, the treatment of carbon residue mostly adopts flotation method, and the electrolyte obtained after flotation is returned to the electrolysis cell, but the byproduct carbon residue still cannot be effectively and reasonably utilized.

[0003] At the same time, the roasting process of the aluminum anode is also a link where a large amount of pollutants are produced. The roasting process produces asphalt flue gas, which is recovered by an electric tar precipitator to form waste tar, which has a pungent odor and contains various carcinogens. Such pollutants are listed as hazardous waste in the National Hazardous Waste List, but there is currently a lack of suitable treatment technology. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application aims to provide a method for resource utilization of aluminum electrolysis carbon residue, which utilizes aluminum electrolysis carbon residue to prepare a desulfurizing agent, and realizes the treatment and utilization of hazardous waste resources by utilizing aluminum electrolysis carbon residue, waste tar obtained by roasting of aluminum anode and / or cathode.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] A method for resource utilization of aluminum electrolysis carbon residue, comprising the following steps:

[0007] S1, pretreatment: drying and grinding the aluminum electrolysis carbon residue to obtain a first material;

[0008] S2, activation: placing the first material obtained in step S1 in a tubular furnace, and under the condition of heating, introducing a gas to activate to obtain a second material;

[0009] S3, impregnation treatment: the second material obtained in step S2 is mixed with a salt solution of a third material, heated and stirred, and then the excess salt solution is removed, and a fourth material is obtained by filtration; the third material is one or a combination of Fe(NO3)3.9H2O, Fe(NO3)2, Cu(NO3)2, Zn(NO3)2, and Ni(NO3)2.6H2O;

[0010] S4, forming: the fourth material obtained in step S3 is added with a binder and a pore-forming agent, and then a fifth material is obtained by extrusion forming;

[0011] S5, heat treatment: the fifth material obtained in step S4 is placed in a tube furnace for heat treatment to obtain a desulfurizer.

[0012] Further, the aluminum electrolysis carbon residue is the carbon-containing material left after the electrolyte is obtained by flotation of the carbon residue obtained from electrolytic aluminum, and the burn loss rate thereof at 900℃ is 70-90%.

[0013] Further, in step S1, the drying temperature is 90-150℃, and the powder grinding requirement is 100-200 mesh.

[0014] Further, in step S2, the gas is water vapor, the activation time is 0.5-5h, the activation temperature is 500-1000℃, and the amount of water vapor is 3-5 times the mass of the first material.

[0015] Further, in step S4, the binder is waste tar obtained by baking carbon anode and / or cathode for aluminum, and the addition amount is 10-20% of the total mass of the fourth material and the binder, and the pore-forming agent is one or a combination of ammonium bicarbonate or starch, and the addition amount is 0-5% of the total mass of the fourth material and the binder.

[0016] Further, in step S5, the heat treatment temperature is 350-550℃, the heat treatment time is 5-10h, and the heat treatment is carried out in a nitrogen or argon atmosphere.

[0017] Further, in step S3, the amount of the third material is 1-2:10 of the mass ratio of transition metal oxide / desulfurizer.

[0018] The application also provides a desulfurizer prepared by the above method.

[0019] The application has the following advantages:

[0020] (1) The desulfurizer prepared by the application is suitable for removing inorganic sulfur (H2S) in trace oxygen or oxygen-free industrial gases such as coal gas, natural gas, blast furnace gas, biogas, and synthetic gas, and the limit sulfur capacity can reach 9-17.5%.

[0021] (2) The desulfurizer prepared by the present application can improve the saturated sulfur capacity of the desulfurizer, because the binder tar is carbonized and part of the small-molecule organic matters are separated during the calcination process, leaving a large number of apparent pores.

[0022] (3) The method of the present application uses aluminum electrolysis carbon slag to prepare the desulfurizer, and the carbon slag contains a large amount of F element, which is beneficial to the uniform dispersion of active components such as Fe, Ni and Cu on the support.

[0023] (4) The method of the present application uses aluminum industry hazardous waste electrolysis carbon slag and calcination waste tar to prepare H2S removal agent, which can reduce the production cost of the desulfurizer.

[0024] (5) The method of the present application is simple, green and economical, and environmentally friendly. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The method flowchart of the embodiments of the present application.

[0026] Figure 2 The pore size distribution diagram of the desulfurizer of the implementation case 2.

[0027] Figure 3 The adsorption and desorption curve of the desulfurizer of the implementation case 2. DETAILED DESCRIPTION

[0028] The present application will be further described below with reference to the accompanying drawings. It should be noted that the present embodiment is based on the technical solution, and gives a detailed implementation and specific operation process, but the protection scope of the present application is not limited to the present embodiment.

[0029] Example 1

[0030] The byproduct carbon slag obtained after flotation of the electrolytic aluminum carbon slag was dried at 110℃ for 2h, and then crushed, ground, and sieved to obtain carbon slag powder. The carbon slag powder between 100-200 meshes was taken out and used, and was placed in a tube furnace and activated by water vapor at 500℃ for 4h, with the amount of water vapor being 3 times the mass of the activated carbon slag. A certain amount of Fe(NO3)3 was dissolved in water, and after complete dissolution, an equal volume of the carrier was immersed. The addition ratio of the iron nitrate was controlled to be 15% of Fe2O3 in the entire desulfurizer after calcination. The carbon calcination waste tar was mixed at 180℃, kneaded, and formed into a desulfurizer precursor, which was treated at 550℃ in N2 atmosphere for 5h to obtain the desulfurizer.

[0031] The hydrogen sulfide removal agent prepared by the method has a mass fraction of 15% of Fe2O3, a mass fraction of 85% of carbon from carbon residue and tar, and 10% of the total mass of carbon residue and tar of waste coke oven tar, and the prepared desulfurizer has a saturated breakthrough sulfur capacity of 150 mg / g of desulfurizer.

[0032] Example 2

[0033] The byproduct carbon residue obtained after flotation of electrolytic aluminum carbon residue is dried at 110 DEG C for 2 hours, and is crushed, ground, and sieved to obtain carbon residue powder. The carbon residue powder between 100-200 meshes is taken out and used. The carrier is obtained by using water vapor activation at 1000 DEG C for 4 hours, and the amount of water vapor is 3 times the mass of the activated carbon residue. A certain amount of Cu(NO3)2 and Zn(NO3)2 is dissolved in water, and after complete dissolution, the same volume is impregnated on the carrier. The addition ratio of Cu(NO3)2 and Zn(NO3)2 is controlled to be 20% of the sum of CuO and ZnO in the final desulfurizer. The desulfurizer precursor is prepared by mixing and kneading waste coke oven tar at 180 DEG C, and the desulfurizer is obtained by treating at 550 DEG C in N2 atmosphere for 5 hours.

[0034] The hydrogen sulfide removal agent prepared by the method has a mass fraction of 15% of Fe2O3, a mass fraction of 85% of carbon from carbon residue and tar, and 10% of the total mass of carbon residue and tar of waste coke oven tar, and the prepared desulfurizer has a saturated breakthrough sulfur capacity of 150 mg / g of desulfurizer.

[0035] Example 3

[0036] The byproduct carbon residue obtained after flotation of electrolytic aluminum carbon residue is dried at 110 DEG C for 2 hours, and is crushed, ground, and sieved to obtain carbon residue powder. The carbon residue powder between 100-200 meshes is taken out and used. The carrier is obtained by using water vapor activation at 1000 DEG C for 4 hours, and the amount of water vapor is 3 times the mass of the activated carbon residue. A certain amount of Cu(NO3)2 and Zn(NO3)2 is dissolved in water, and after complete dissolution, the same volume is impregnated on the carrier. The addition ratio of Cu(NO3)2 and Zn(NO3)2 is controlled to be 20% of the sum of CuO and ZnO in the final desulfurizer. The desulfurizer precursor is prepared by mixing and kneading waste coke oven tar at 180 DEG C, and the desulfurizer is obtained by treating at 550 DEG C in N2 atmosphere for 5 hours.

[0037] The hydrogen sulfide removal agent prepared by the method has a mass fraction of 15% of Fe2O3, a mass fraction of 85% of carbon from carbon residue and tar, and 10% of the total mass of carbon residue and tar of waste coke oven tar, and the prepared desulfurizer has a saturated breakthrough sulfur capacity of 150 mg / g of desulfurizer.

[0038] Example 4

[0039] The by-product carbon residue obtained after flotation of electrolytic aluminum carbon residue was dried at 110°C for 2h, and then crushed, ground, and sieved to obtain carbon residue powder. The carbon residue powder between 100-200 mesh was taken and placed in a tube furnace, activated with water vapor at 600°C for 2h, and the amount of water vapor was 3 times the mass of the activated carbon residue. A certain amount of Fe(NO3)3 was dissolved in water, and after complete dissolution, an equal volume was impregnated on the carrier. The addition ratio of iron nitrate was controlled so that the Fe2O3 in the final desulfurizer accounted for 20% of the total desulfurizer. The desulfurizer precursor was prepared by mixing and kneading, shaping, etc. at a temperature of 180°C with carbon, waste coke oven tar, and starch. The desulfurizer was obtained by treating at 550°C in N2 atmosphere for 5h.

[0040] The hydrogen sulfide removal agent prepared by the above method had a mass fraction of Fe2O3 of 20%, a mass fraction of carbon from carbon residue and tar of 80%, and waste coke oven tar and starch each accounting for 15% and 5% of the total mass of carbon residue and tar. The prepared desulfurizer had a saturated breakthrough sulfur capacity of 175mg / g of desulfurizer.

[0041] Example 5

[0042] The by-product carbon residue obtained after flotation of electrolytic aluminum carbon residue was dried at 110°C for 2h, and then crushed, ground, and sieved to obtain carbon residue powder. The carbon residue powder between 100-200 mesh was taken and placed in a tube furnace, activated with water vapor at 600°C for 2h, and the amount of water vapor was 3 times the mass of the activated carbon residue. A certain amount of Fe(NO3)3 was dissolved in water, and after complete dissolution, an equal volume was impregnated on the carrier. The addition ratio of iron nitrate was controlled so that the Fe2O3 in the final desulfurizer accounted for 20% of the total desulfurizer. The desulfurizer precursor was prepared by mixing and kneading, shaping, etc. at a temperature of 180°C with carbon, waste coke oven tar, and starch. The desulfurizer was obtained by treating at 550°C in N2 atmosphere for 5h.

[0043] The hydrogen sulfide removal agent prepared by the above method had a mass fraction of Fe2O3 of 20%, a mass fraction of carbon from carbon residue and tar of 80%, and waste coke oven tar and starch each accounting for 15% and 5% of the total mass of carbon residue and tar. The prepared desulfurizer had a saturated breakthrough sulfur capacity of 175mg / g of desulfurizer.

[0044] Example 6

[0045] The by-product carbon residue obtained after flotation of electrolytic aluminum carbon residue is dried at 110°C for 2h, and is crushed, ground, and sieved to obtain carbon residue powder. Carbon residue powder of about 100-200 mesh is taken and used, and is placed in a tube furnace. Water vapor activation is carried out at 600°C for 4h, and the amount of water vapor is 5 times the mass of the activated carbon residue. A certain amount of Fe(NO3)3 is dissolved in water, and after complete dissolution, an equal volume is impregnated on the carrier. The addition ratio of iron nitrate is controlled so that the Fe2O3 in the final obtained desulfurizer accounts for 15% of the total desulfurizer mass. The desulfurizer precursor is prepared by mixing and kneading, molding, and the like at a temperature of 180°C with carbon and waste coke oven tar. The desulfurizer is obtained by treating at 550°C in a N2 atmosphere for 5h.

[0046] The hydrogen sulfide removal agent prepared by the above method has a mass fraction of Fe2O3 of 15%, and the carbon prepared from aluminum industry hazardous waste carbon residue and tar has a mass fraction of 85%, and the waste coke oven tar accounts for 10% of the total mass of the carbon residue and the tar. The prepared desulfurizer has a saturated breakthrough sulfur capacity of 90mg / g of desulfurizer.

[0047] Example 7

[0048] The by-product carbon residue obtained after flotation of electrolytic aluminum carbon residue is dried at 110°C for 2h, and is crushed, ground, and sieved to obtain carbon residue powder. Carbon residue powder of about 100-200 mesh is taken and used, and is placed in a tube furnace. Water vapor activation is carried out at 600°C for 4h, and the amount of water vapor is 5 times the mass of the activated carbon residue. A certain amount of Fe(NO3)3 is dissolved in water, and after complete dissolution, an equal volume is impregnated on the carrier. The addition ratio of iron nitrate is controlled so that the Fe2O3 in the final obtained desulfurizer accounts for 15% of the total desulfurizer mass. The desulfurizer precursor is prepared by mixing and kneading, molding, and the like at a temperature of 180°C with carbon and waste coke oven tar. The desulfurizer is obtained by treating at 550°C in a N2 atmosphere for 5h.

[0049] The hydrogen sulfide removal agent prepared by the above method has a mass fraction of Fe2O3 of 15%, and the carbon prepared from aluminum industry hazardous waste carbon residue and tar has a mass fraction of 85%, and the waste coke oven tar accounts for 10% of the total mass of the carbon residue and the tar. The prepared desulfurizer has a saturated breakthrough sulfur capacity of 90mg / g of desulfurizer.

[0050] Example 8

[0051] The by-product carbon residue obtained by flotation of electrolytic aluminum carbon residue is dried at 110°C for 2h, crushed, ground, sieved and the like to obtain carbon residue powder, and the 100-200 mesh carbon residue powder is taken out for use, placed in a tube furnace, activated with water vapor at 600°C for 4h, the amount of water vapor is 5 times the mass of the activated carbon residue, a certain amount of Fe(NO3)3 is dissolved in water, after complete dissolution, impregnated with an equal volume of carrier, the addition ratio of iron nitrate is controlled to be 15% of Fe2O3 in the final desulfurizer, mixed with waste coke oven tar at 180°C, kneaded, shaped and the like to prepare a desulfurizer precursor, treated at 350°C under N2 atmosphere for 10h to obtain a desulfurizer.

[0052] The hydrogen sulfide removal agent prepared by the above method has a mass fraction of 15% of Fe2O3, a mass fraction of 85% of carbon prepared from aluminum industry hazardous waste carbon residue and tar, and a mass fraction of 10% of waste coke oven tar in the total mass of carbon residue and tar, and the prepared desulfurizer has a saturated breakthrough sulfur capacity of 90mg / g of desulfurizer.

[0053] For those skilled in the art, various corresponding changes and modifications can be given according to the above technical solutions and concepts, and all these changes and modifications should be included in the protection scope of the claims of the present application.

Claims

1. A method for resource utilization of aluminum electrolysis carbon residue, characterized in that, It comprises the following steps: S1, pretreatment: drying and grinding the aluminum electrolysis carbon residue to obtain a first material; S2, activation: placing the first material obtained in step S1 in a tube furnace, and under heating conditions, passing in a gas to activate to obtain a second material; the gas is water vapor, the activation time is 0.5-5h, the activation temperature is 500-1000℃, and the water vapor dosage is 3-5 times the mass of the first material; S3, impregnation treatment: mixing the second material obtained in step S2 with a salt solution of a third material, heating and stirring, then removing the excess salt solution, and filtering to obtain a fourth material; the third material is one or a combination of Fe(NO3)3·9H2O, Fe(NO3)2, Cu(NO3)2, Zn(NO3)2, and Ni(NO3)2·6H2O; S4, forming: adding a binder and a pore-forming agent to the fourth material obtained in step S3, and after extrusion forming, a fifth material is obtained; the binder is waste tar obtained by baking aluminum carbon anode and / or cathode, and the addition amount is 10-20% of the total mass of the fourth material and the binder, and the pore-forming agent is one or a combination of ammonium bicarbonate or starch, and the addition amount is 0-5% of the total mass of the fourth material and the binder; S5, heat treatment: placing the fifth material obtained in step S4 in a tube furnace for heat treatment to obtain a desulfurizer; the heat treatment temperature is 350-550℃, the heat treatment time is 5-10h, and the heat treatment is carried out in a nitrogen or argon atmosphere.

2. The method of claim 1, wherein, The aluminum electrolysis carbon residue is the carbon-containing material left after the electrolyte is obtained by flotation from the carbon residue obtained during electrolytic aluminum production, and its burnout rate at 900℃ is 70-90%.

3. The method of claim 1, wherein, In step S1, the drying temperature is 90-150℃, and the grinding requirement is 100-200 mesh.

4. The method of claim 1, wherein, In step S3, the amount of the third material is 1-2:10 based on the mass ratio of transition metal oxide / desulfurizer.

5. A desulfurizer prepared by the method of any one of claims 1-4.

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