CN109487075B

CN109487075B - Method for comprehensively recovering valuable elements in aluminum-based petroleum refining catalyst by utilizing reducing gas

Info

Publication number: CN109487075B
Application number: CN201811550748.3A
Authority: CN
Inventors: 徐盛明; 王文强; 韩宇; 张磊; 李震
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2018-12-18
Filing date: 2018-12-18
Publication date: 2020-07-07
Anticipated expiration: 2038-12-18
Also published as: CN109487075A

Abstract

The invention discloses a method for comprehensively recovering valuable elements in an aluminum-based petroleum refining catalyst by utilizing reducing gas, which comprises the steps of pretreating a waste catalyst by adopting a reducing heat treatment process, respectively generating water-soluble aluminum salt, magnetic and acid-soluble metal simple substance nickel cobalt and low-valent oxide, simple substance or carbide of acid-resistant and alkali-resistant rare metal by utilizing three types of valuable metal elements in the waste catalyst, so that the property difference of valuable element compounds needing to be recovered is enlarged, extracting aluminum oxide by utilizing an aqueous solution or an alkali solution, leaching nickel and cobalt by utilizing a magnetic separation or an acid solution, and enriching and recovering the rare metal in leaching slag. The method has the advantages of simple and reasonable process, economic and environment-friendly reducing agent, capability of realizing high-efficiency separation and comprehensive recovery of valuable elements in the waste catalyst, remarkable economic benefit and the like.

Description

Method for comprehensively recovering valuable elements in aluminum-based petroleum refining catalyst by utilizing reducing gas

Technical Field

The invention relates to a method for comprehensively recovering valuable elements in an aluminum-based petroleum refining catalyst by utilizing reducing gas, belonging to the technical field of nonferrous metallurgy.

Background

Petrochemical is a catalyst-centered industrial sector, with about 90% of petroleum refining reactions being carried out with the aid of catalysts. The catalyst can be deactivated due to phenomena of carbon deposition, heavy metal poisoning, active phase sintering and the like in the using process. When these deactivated catalysts cannot be economically regenerated, the catalysts become spent catalysts. The waste catalyst usually contains organic matters such as carbon deposit and residual oil, sulfur, heavy metal elements such as nickel and cobalt, rare metal elements such as tungsten, molybdenum and vanadium, carrier alumina and the like. If the waste catalyst is not harmlessly disposed, unstable toxic and harmful substances in the waste catalyst are easy to diffuse into the environment in which people depend to live, so that the problem of serious environmental pollution is caused. At present, the waste catalyst has been listed in the hazardous waste list (national hazardous waste list 2016, waste category: HW50 waste catalyst, waste code: 258-. On the other hand, the contents of heavy metals and rare metal elements contained in the waste catalyst are far higher than those of natural minerals, and the waste catalyst is a high-quality secondary resource. Therefore, it is necessary to extract valuable elements from the spent catalyst and to dispose of the spent catalyst harmlessly, both from the viewpoint of environmental protection and from the viewpoint of resource saving.

At present, many researches on the recovery of valuable elements in the waste catalyst of petroleum refining have been carried out, and researchers develop recovery processes including pyrometallurgy, hydrometallurgy, biological metallurgy and the combination of various metallurgical methods. The method is widely applied to the process of firstly oxidizing roasting (or soda roasting) and then wet extraction. The oxidation roasting process can remove carbon deposition in the waste catalyst, and simultaneously convert sulfides of molybdenum, vanadium, nickel, cobalt and the like into oxides, so as to be beneficial to the subsequent extraction process. The subsequent wet extraction process can be divided into an acidic leaching system and an alkaline leaching system according to the acidity and alkalinity of the used leaching agent. In an acid leaching system, almost all metal elements are leached to obtain leaching liquid with enriched valuable metal elements, and then separation and recovery of the elements are realized by methods such as solvent extraction, ion exchange, adsorption or chemical precipitation. However, such methods are often too complex to be a process and costly. In addition, most of the acidic leaching agents are difficult to recycle, and only neutralization treatment can be performed finally. In an alkaline leaching system, only acidic oxides and amphoteric oxides can be leached, so that the leaching system has certain selectivity and is beneficial to separation of valuable elements. The method has the disadvantages that the separation process of rare metals such as Mo and V and Al in amphoteric oxides is difficult, and the products with higher purity can be obtained by multiple times of separation and purification.

In addition, researchers have developed some non-wet methods of spent catalyst recovery processes. For example, the Chinese patent application No. 201510324532.5, the waste catalyst, the iron-containing material, the cosolvent and the coke are subjected to the pyrometallurgical smelting at 1550-. However, this method is suitable for spent catalysts with a high content of valuable metals, which would otherwise be economically disadvantageous. Moreover, the components of the iron alloy obtained by the sulphur-making smelting are complex and are very difficult to utilize. In addition, the carrier alumina, which is originally regarded as a high-quality aluminum resource in the spent catalyst, is wasted through slagging and cannot be effectively utilized. The document (Int J Miner process.75(2005)249-253) reports a process for recovering molybdenum from spent catalysts by carbothermic reduction plus molten salt electrolysis, in which carbon and limestone are added to the spent catalyst and carbothermic reduction is carried out at 1150 ℃ to convert molybdenum to molybdenum metal and calcium to calcium sulfide. Then washing off calcium-containing substances by using water to obtain impure metal molybdenum, and purifying by adopting a molten salt electrolysis method at 1500 ℃ to obtain pure molybdenum. The method has the advantages of high temperature and high energy consumption in the two-stage process, and the nickel, the cobalt, the aluminum and the like in the waste catalyst cannot be recovered. In addition, during the calcium removal phase of the water wash, calcium sulfide reacts with water, releasing hydrogen sulfide, a toxic gas. Therefore, the method is not of substantial industrial value.

Therefore, the existing recovery process of the petroleum refining waste catalyst has the defects of complex element separation process, long flow, high recovery cost, difficulty in realizing comprehensive recovery of valuable elements and the like, and therefore, a new recovery process of the waste catalyst is urgently needed to be developed to realize high-efficiency low-cost recovery of the valuable elements in the waste catalyst.

Disclosure of Invention

Aiming at the defect of complex separation process of valuable elements in the prior art of recovering the petroleum refining waste catalyst, the invention provides a method for realizing the efficient separation and recovery of the valuable elements by using reducing gas to reduce and pretreat the petroleum refining waste catalyst.

In order to achieve the aim, the invention provides a method for comprehensively recovering valuable elements in an aluminum-based petroleum refining catalyst by using reducing gas, which comprises the following steps:

the method comprises the following steps: fully grinding and mixing the aluminum-based waste catalyst subjected to oxidation roasting and the alkali metal salt, heating to a proper temperature at a certain heating rate in a reducing atmosphere to perform a reduction reaction, and keeping the temperature for a certain time until the reaction is completed to obtain a reduced material;

step two: adding the carbothermic material obtained in the step one into pure water or an alkaline aqueous solution to dissolve soluble aluminum salt in the carbothermic material, and filtering to obtain an aluminum-containing solution and filter residue enriched with valuable metal elements; extracting aluminum from the obtained aluminum-containing solution; concentrating and crystallizing the alkali metal salt solution obtained after aluminum extraction to obtain alkali metal salt, and returning to the step one;

step three: recovering heavy metal elements from the filter residue enriched with valuable metal elements obtained in the step two by a magnetic separation or acidic aqueous solution dissolution method; after extracting heavy metal elements, obtaining nonmagnetic magnetic separation slag or acid-insoluble leaching slag, namely carbide of rare metal.

The aluminum-based petroleum refining waste catalyst is a used catalyst, and is inactivated due to phenomena such as carbon deposition, heavy metal poisoning, active phase sintering and the like in the using process, so that economic regeneration cannot be realized. The aluminum-based petroleum refining waste catalyst comprises carrier gamma-Al₂O₃Rare metal elements such as one or more of Mo (molybdenum), V (vanadium) and W (tungsten), and one or both of heavy metal elements Ni (nickel) and Co (cobalt). In general, the above-mentioned spent catalyst may contain other elementsElements such as carbon, sulfur, and the like.

The oxidizing roasting in the first step of the invention is to put the aluminum-based petroleum refining waste catalyst into air and roast the catalyst for 0.1 to 10.0 hours at the temperature of 400 to 700 ℃.

In some embodiments, the aluminum-based petroleum refinery spent catalyst is Ni-Mo/γ -Al₂O₃The catalyst contains the following elements after oxidizing roasting: 15-40% of Al, 1-20% of Ni, 0-12% of Co, 0-12% of V, 1-20% of Mo, for example, the following elements are contained: 28.1% of Al, 12.3% of Ni, 6.1% of V and 4.7% of Mo, or the following elements: 27.1% of Al, 12.1% of Ni12, 5.8% of V and 4.6% of Mo. In some examples, the content of V in the aluminum-based petroleum refining waste catalyst after the oxidizing roasting is 0.5-12%.

In some embodiments, the aluminum-based spent petroleum refining catalyst is Co-Mo/γ -Al₂O₃The catalyst contains the following elements after oxidizing roasting: 15-40% of Al, 1-20% of Co, 0-15% of Ni, 0-12% of V, 1-20% of Mo, for example, the following elements are contained: 37.9 percent of Al, 5.4 percent of Co, 1.8 percent of V and 12.7 percent of Mo. In some examples, the content of V in the aluminum-based petroleum refining waste catalyst after the oxidizing roasting is 0.5-12%.

In the invention, the reducing atmosphere in the first step is one or a mixture of more of carbon monoxide, methane, ethane, propane and hydrogen.

In the present invention, the alkali metal salt in step one is selected from one or more of sodium carbonate, sodium bicarbonate, sodium hydroxide, sodium oxide, sodium peroxide, potassium carbonate, potassium bicarbonate, potassium hydroxide, potassium oxide, potassium peroxide, lithium carbonate, lithium bicarbonate, lithium hydroxide and lithium oxide. In order to better extract the rare metal elements (molybdenum and/or vanadium and/or tungsten), the heavy metal elements (nickel and/or cobalt) and the aluminum element in the waste catalyst, the addition amount of the alkali metal salt is preferably 0.6 to 3.0 times of the total alkali metal salt amount required for respectively converting the rare metal elements (molybdenum and/or vanadium and/or tungsten) and the aluminum in the aluminum-based petroleum refining waste catalyst into their corresponding salts.

In the first step of the invention, the heating rate is 0.01 ℃/min-50 ℃/min (preferably 4 ℃/min-15 ℃/min), and/or the temperature of the carbothermic reduction reaction is 700 ℃ -1200 ℃ (preferably 900 ℃ -1100 ℃), and/or the time of the carbothermic reduction reaction is 10 min-24 h. Researches find that during the carbothermic reduction reaction, if the temperature is lower than 900 ℃, the molybdenum and vanadium can be incompletely carbonized, so that the molybdenum and vanadium are dissolved and lost in the extraction rate process; if the temperature is higher than 1100 ℃, the phase of aluminate can be changed, which is not beneficial to the extraction of aluminum; therefore, the temperature is preferably 900 to 1100 ℃.

The alkali used in the alkaline aqueous solution in the second step of the present invention is the same as the alkali metal salt used in the first step. Preferably, the concentration of the alkaline aqueous solution in the second step is between 0.01mol/L and 8 mol/L.

In the second step of the invention, the temperature for extracting aluminum from the obtained aluminum-containing solution is 0-100 ℃.

The acidic aqueous solution in step three of the present invention may be one or more of hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, ethylenediaminetetraacetic acid, and other non-oxidizing acids.

The temperature for recovering heavy metal elements by the three-purpose method for dissolving the acidic aqueous solution in the steps is 0-100 ℃.

On the basis of the common knowledge in the field, the above preferred conditions can be combined with each other to obtain the preferred embodiments of the invention.

The method of the invention adopts a reduction heat treatment process to pretreat the waste catalyst, so that three types of valuable metal elements in the waste catalyst respectively generate water-soluble meta-aluminate, magnetic and acid-soluble metal simple substance nickel cobalt and acid-resistant and alkali-resistant low-valent oxide, simple substance or carbide of rare metal, thereby enlarging the property difference of valuable element compounds to be recovered, then extracting aluminum oxide by using an aqueous solution or an alkali solution, then leaching and extracting nickel and cobalt by using a magnetic separation or an acid solution, and enriching and recovering the rare metal in leaching slag.

The invention has the following advantages:

1) the reducing agent used in the invention is a conventional chemical product, is cheap and easy to obtain, and has almost no environmental hazard;

2) the invention can realize the reduction of nickel and cobalt and the reduction or carbonization of rare metals of tungsten, molybdenum and vanadium while realizing the sintering of alumina, has simple required equipment and convenient operation and has strong industrial application value;

3) the method can realize the recovery of all elements of nickel, cobalt, molybdenum, vanadium, tungsten and carrier alumina in the petroleum refining waste catalyst, has simple element separation process and high recovery rate, the recovery rate of aluminum can reach more than 98 percent, the recovery rates of nickel and cobalt can reach more than 99 percent, and the recovery rates of tungsten, molybdenum and vanadium can respectively reach more than 99 percent, 98 percent and 96 percent, and has very high economic prospect.

In conclusion, the method has the advantages of simple and reasonable process, economic and environment-friendly reducing agent, capability of realizing high-efficiency separation and comprehensive recovery of valuable elements in the waste catalyst, remarkable economic benefit and the like.

Detailed Description

The following examples are intended to further illustrate the present invention, but not to limit the scope of the claims.

Example 1

(1) Reduction roasting process

Waste catalyst Ni-Mo/gamma-Al for petroleum hydrodesulfurization₂O₃The following elements are contained after the oxidizing roasting at the temperature of 550 ℃: 28.1 percent of Al, 12.3 percent of Ni, 6.1 percent of V and 4.7 percent of Mo, adding sodium carbonate according to 1.2 times of the theoretical requirement, mixing and grinding until all the grinding materials pass through a 200 molybdenum screen. Placing the grinding material in a heating furnace, introducing carbon monoxide at a flow rate of 100mL/min after exhausting air, heating to 950 ℃ at a heating rate of 5 ℃/min, preserving heat for 180min, cooling to room temperature, and taking out.

(2) Fractional extraction process of valuable elements

Adding the reduction product into 2mol/L sodium hydroxide solution, stirring and leaching in 80 ℃ water bath for 60min, filtering while hot to obtain sodium aluminate solution, wherein the leaching rate of aluminum can reach 99.1%, the concentration of metal ions such as molybdenum, vanadium and the like in the sodium aluminate solution can be almost ignored, and aluminum oxide can be directly prepared and sodium carbonate can be recovered after desiliconization. Washing the filter residue with deionized water for multiple times to obtain leaching residue, adding 0.5mol/L sulfuric acid solution into the leaching residue, stirring and leaching for 30min at 25 ℃, wherein the leaching rate of nickel exceeds 99%, the dissolution loss of molybdenum and vanadium is less than 0.1%, filtering to obtain a nickel-rich solution (used for extracting nickel) and acid leaching residue, the leaching residue is the enrichment of molybdenum and vanadium, and the recovery rates of molybdenum and vanadium can reach 99% and 98%.

Example 2

(1) Reduction roasting process

Waste catalyst Ni-Mo/gamma-Al for petroleum hydrodesulfurization₂O₃After being oxidized and roasted at 650 ℃, the alloy contains the following elements of Al27.1%, Ni 12.1%, V5.8% and Mo 4.6%, sodium carbonate is added according to 1.3 times of the theoretical requirement, and the mixture is mixed and ground until all the grinding materials pass through a 200 molybdenum mesh screen. Placing the grinding material in a heating furnace, introducing hydrogen at the flow rate of 100mL/min after exhausting air, heating to 1050 ℃ at the heating rate of 5 ℃/min, preserving heat for 100 min, cooling to room temperature, and taking out.

(2) Fractional extraction process of valuable elements

Adding the reduction product into 1mol/L sodium hydroxide solution, stirring and leaching for 40min in 70 ℃ water bath, filtering while hot to obtain sodium aluminate solution, wherein the leaching rate of aluminum can reach 99.3%, metal ions such as molybdenum, vanadium and the like can hardly be detected in the sodium aluminate solution, and directly preparing alumina and recovering sodium carbonate after desiliconization. Washing the filter residue with deionized water for multiple times to obtain leaching residue, adding 2mol/L sulfuric acid solution into the leaching residue, stirring and leaching for 30min at 25 ℃, wherein the leaching rate of nickel reaches 99.5%, the dissolution rate of molybdenum and vanadium is less than 0.1%, and filtering to obtain nickel-rich solution (used for extracting nickel) and acid leaching residue, wherein the leaching residue is simple substances of molybdenum and vanadium.

Example 3

(1) Reduction roasting process

Waste catalyst Ni-Mo/gamma-Al for petroleum hydrodesulfurization₂O₃The catalyst contains the following elements after being oxidized and roasted at 500 ℃: 28.1 percent of Al, 12.3 percent of Ni, 6.1 percent of V and 4.7 percent of Mo, adding sodium carbonate according to 2.0 times of the theoretical requirement, mixing and grinding until all the grinding materials pass through a 200 molybdenum screen. Placing the abrasive inAnd (3) placing the grinding material in a heating furnace under the protection of nitrogen, introducing methane at the flow rate of 100mL/min after exhausting air, heating to 950 ℃ at the heating rate of 10 ℃/min, preserving heat for 90min, cooling to room temperature, and taking out.

(2) Fractional extraction process of valuable elements

Adding the reduction product into deionized water, stirring and leaching for 120min in a water bath at 80 ℃, filtering while hot to obtain a sodium aluminate solution, wherein the leaching rate of aluminum can reach 99.1%, the concentration of metal ions such as molybdenum, vanadium and the like in the sodium aluminate solution can be almost ignored, and aluminum oxide can be directly prepared and sodium carbonate can be recovered after desiliconization. Washing the filter residue with deionized water for multiple times to obtain leaching residue, and separating the leaching residue with magnetic separation to obtain magnetic separation material and magnetic separation residue, wherein the magnetic separation material is simple substance nickel, and the magnetic separation residue is enriched molybdenum and vanadium.

Example 4

(1) Reduction roasting process

Waste catalyst Co-Mo/gamma-Al for petroleum hydrodesulfurization₂O₃The following elements are contained after the oxidizing roasting at the temperature of 550 ℃: 37.9 percent of AlC, 5.4 percent of Co, 1.8 percent of V and 12.7 percent of Mo. Sodium hydroxide was added at 1.5 times the theoretical requirement and mixed and ground until the whole millbase passed through a 150 molybdenum mesh screen. Placing the abrasive in a heating furnace under the protection of argon, placing the abrasive in the heating furnace, exhausting air, introducing mixed gas of hydrogen and carbon monoxide at a flow rate of 100mL/min, heating to 850 ℃ at a heating rate of 4 ℃/min, preserving heat for 180min, cooling to room temperature, and taking out.

(2) Fractional extraction process of valuable elements

Adding the reduction product into 0.5mol/L sodium hydroxide solution, stirring and leaching in 80 ℃ water bath for 60min, filtering while hot to obtain sodium aluminate solution, wherein the leaching rate of aluminum is over 99.2%, the concentration of metal ions such as molybdenum, vanadium and the like in the sodium aluminate solution can be almost ignored, aluminum oxide can be directly prepared and sodium carbonate can be recovered after desiliconization, and the sodium carbonate returns to the carbothermic reduction process. Washing the filter residue with deionized water for multiple times to obtain leaching residue, adding 0.5mol/L sulfuric acid solution into the leaching residue, stirring and leaching at 80 ℃ for 30min, wherein the cobalt leaching rate exceeds 99.5%, and filtering to obtain cobalt-rich solution (used for extracting cobalt) and acid leaching residue, wherein the leaching residue is molybdenum and vanadium enrichment.

Example 5

(1) Reduction roasting process

Waste catalyst Co-Mo/gamma-Al for petroleum hydrodesulfurization₂O₃The following elements are contained after the oxidizing roasting at the temperature of 550 ℃: 37.9 percent of AlC, 5.4 percent of Co, 1.8 percent of V and 12.7 percent of Mo. Sodium hydroxide was added at 1.5 times the theoretical requirement and mixed and ground until the whole millbase passed through a 250 molybdenum mesh screen. Placing the abrasive in a heating furnace under the protection of argon, placing the abrasive in the heating furnace, exhausting air, introducing ethane at a flow rate of 100mL/min, heating to 950 ℃ at a heating rate of 15 ℃/min, preserving heat for 180min, cooling to room temperature, and taking out.

(2) Fractional extraction process of valuable elements

Adding the reduction product into 1.5mol/L sodium hydroxide solution, stirring and leaching for 120min in water bath at 60 ℃, filtering while hot to obtain sodium aluminate solution, wherein the leaching rate of aluminum is over 98.5%, the concentration of metal ions such as molybdenum, vanadium and the like in the sodium aluminate solution can be almost ignored, and aluminum oxide can be directly prepared and sodium carbonate can be recovered after desiliconization. Washing the filter residue with deionized water for multiple times to obtain leaching residue, adding 1.0mol/L hydrochloric acid solution into the leaching residue, stirring and leaching at 50 ℃ for 60min, wherein the cobalt leaching rate exceeds 99.1%, and obtaining cobalt-rich solution (used for extracting cobalt and nickel) and acid leaching residue, wherein the leaching residue is molybdenum and vanadium enrichment.

Claims

1. A method for comprehensively recovering valuable elements in an aluminum-based petroleum refining catalyst by utilizing reducing gas is characterized by comprising the following steps:

the method comprises the following steps: fully grinding and mixing the aluminum-based waste catalyst subjected to oxidation roasting and the alkali metal salt, heating to 900-1100 ℃ at a certain heating rate in a reducing atmosphere to perform a reduction reaction, and keeping the temperature for a certain time until the reaction is finished to obtain a reducing material; the reducing atmosphere is one or a mixture of more of carbon monoxide, methane, ethane and propane;

step two: adding pure water or an alkaline aqueous solution into the carbothermic material obtained in the step one to dissolve soluble aluminum salt in the carbothermic material, filtering to obtain an aluminum-containing solution and filter residue enriched with valuable metal elements, and extracting aluminum from the obtained aluminum-containing solution; concentrating and crystallizing the alkali metal salt solution obtained after aluminum extraction to obtain alkali metal salt, and returning to the step one;

step three: recovering heavy metal elements from the filter residue enriched with valuable metal elements obtained in the step two by a magnetic separation or acidic aqueous solution dissolution method; extracting heavy metal elements to obtain nonmagnetic magnetic separation slag or acid-insoluble leaching slag, namely carbides of rare metals; the rare metal elements are one or more of Mo, V and W, and the heavy metal elements are one or two of Ni and Co.

2. The method as claimed in claim 1, wherein the aluminum-based petroleum refining spent catalyst of step one comprises γ -Al as a carrier₂O₃Rare metal elements and heavy metal elements.

3. The method of claim 2, wherein step one said aluminum-based petroleum refinery spent catalyst is Ni-Mo/γ -Al₂O₃The catalyst contains the following elements after oxidizing roasting: al 15-40%, Ni 1-20%, Co 0-15%, V0-12%, Mo 1-20%; or the aluminum-based petroleum refining waste catalyst is Co-Mo/gamma-Al₂O₃The catalyst contains the following elements after oxidizing roasting: al 15-40%, Co 1-20%, Ni 0-15%, V0-12%, Mo 1-20%.

4. The method as claimed in claim 1, wherein the temperature of the oxidizing roasting in the first step is 400-700 ℃.

5. The method as claimed in claim 4, wherein the time for the oxidizing roasting in the first step is 0.1 to 10.0 hours.

6. The method according to any one of claims 1 to 5, wherein the alkali metal salt of step one is selected from the group consisting of sodium carbonate, sodium bicarbonate, sodium hydroxide, sodium oxide, potassium carbonate, potassium bicarbonate, potassium hydroxide, potassium oxide, lithium carbonate, lithium bicarbonate, lithium hydroxide, and lithium oxide.

7. The method according to claim 6, wherein the amount of the alkali metal salt added in the first step is 0.6 to 3.0 times of the total amount of the alkali metal salt required for converting the rare metal element and the aluminum in the aluminum-based petroleum refining waste catalyst into their corresponding salts, respectively.

8. The method according to any one of claims 1 to 5 or 7, wherein the temperature rise rate in the first step is 0.01 ℃/min to 50 ℃/min; and/or the carbothermic reduction reaction time is 10 min-24 h.

9. The method according to any one of claims 1 to 5 or 7, wherein the temperature rise rate in the first step is 4 ℃/min to 15 ℃/min.

10. The method according to any one of claims 1-5, 7, wherein the base used in the alkaline aqueous solution of step two is identical to the base salt used in step one.

11. The method as claimed in claim 10, wherein the concentration of the alkaline aqueous solution in the second step is 0.01 mol/L-8 mol/L.

12. The method of any one of claims 1-5, 7, and 11, wherein the temperature for extracting aluminum from the aluminum-containing solution obtained in step two is 0 ℃ to 100 ℃.

13. The method according to any one of claims 1 to 5, 7 and 11, wherein the acidic aqueous solution in step three is selected from one or more of hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid and ethylenediamine tetraacetic acid.

14. The method of claim 13, wherein the temperature for recovering heavy metal elements by the three-way acidic aqueous solution dissolution method is 0 ℃ to 100 ℃.