Preparation method of crystalline aluminum chloride

Abstract

The invention relates to a preparation method of crystalline aluminum chloride, which comprises the following steps: carrying out at least one acidolysis on aluminum chloride waste liquid by using a hydrochloric acid solution to obtain the crystalline aluminum chloride. The preparation method disclosed by the invention is high in recovery rate, the obtained crystalline aluminum chloride is high in purity and can be directly sold, and compared with a distillation method for crystallizing aluminum chloride, the energy consumption is relatively high, and a hydrogen chloride introducing method is complicated to operate and cannot achieve material balance; energy consumption and cost can be reduced, material balance is achieved, benefits are increased, and operation is simplified.

Description

Technical Field

[0001] The invention belongs to the technical field of waste liquid treatment and relates to a method for preparing crystalline aluminum chloride. Background Art

[0002] At present, the methods for disposing the waste aluminum chloride water produced by hydrolysis after Friedel-Crafts reaction include making polyaluminum chloride, distilling or passing hydrogen chloride to make crystalline aluminum chloride.

[0003] CN114133058A discloses a Friedel-Crafts reaction aluminum-containing wastewater resource utilization method, which first uses an oxidant to oxidize and remove organic macromolecules in the aluminum-containing wastewater, then uses an adsorbent to adsorb particulate impurities in the waste liquid, and refines the waste liquid. After refining, the waste liquid is divided into two parts, one part of the waste liquid is added with alkali to prepare sodium aluminate, and the prepared sodium aluminate is dripped into the other part of the waste liquid, and polyaluminum chloride is obtained after polymerization and aging. The profit of producing polyaluminum chloride in the prior art is too low.

[0004] CN116477651A discloses a method and device for producing crystalline aluminum chloride and PAFC using solid waste, comprising the following steps: (1) drying and preheating solid waste salt sodium chloride, reacting it with concentrated sulfuric acid to generate sodium bisulfate and hydrogen chloride gas through exothermic reaction, and controlling the reaction temperature; (2) subjecting coal gangue to high temperature activation and mechanical activation to obtain activated coal gangue; (3) mixing the activated coal gangue obtained in step (2) with hydrochloric acid and / or the hydrochloric acid mother liquor obtained in step (4), adding iron ore or iron oxide to the mixture for stirring and acid hydrolysis leaching to obtain aluminum chloride solution containing iron chloride and silicon slag; (4) subjecting the chloride-containing coal gangue obtained in step (3) to agitation and acid leaching; The aluminum chloride solution containing iron absorbs the hydrogen chloride gas obtained in step (1) and / or step (5) to precipitate crystalline aluminum chloride, and the obtained hydrochloric acid mother liquor is returned to step (3) for repeated use; (5) the aluminum chloride solution containing iron chloride obtained in step (3) is mixed with the crystalline aluminum chloride obtained in step (4), stirred to make it re-saturated, and hydrolyzed and polymerized under certain temperature and pressure conditions, and hydrogen chloride gas is released, and the obtained polymer product is subjected to evaporation crystallization, pressure filtration, and drying to obtain a PAFC product; (6) the liquid remaining after evaporation crystallization in step (5) is separated by nanofiltration to obtain a salt solution, and a soda solution is added to neutralize and remove impurities before recycling. However, the energy consumption of aluminum chloride crystallization by distillation is high, and the operation of the hydrogen chloride method is complicated and material balance cannot be achieved.

[0005] In summary, it is crucial to develop a method for preparing crystalline aluminum chloride that can overcome the above-mentioned defects. Summary of the invention

[0006] The object of the present invention is to provide a method for preparing crystalline aluminum chloride. The preparation method has a high recovery rate, and the obtained crystalline aluminum chloride has a high purity and can be directly sold. Compared with the high energy consumption of aluminum chloride crystallization by distillation, the complex operation of hydrogen chloride method and the inability to achieve material balance, the preparation method of the present invention can reduce energy consumption and cost, achieve material balance, increase benefits and simplify operation.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for preparing crystalline aluminum chloride, which comprises the following steps: subjecting aluminum chloride waste liquid to acid hydrolysis at least once (for example, twice, three times, four times, five times, six times, etc.) using a hydrochloric acid solution to obtain the crystalline aluminum chloride.

[0009] In the prior art, the products of aluminum chloride waste liquid recovery methods generally include polyaluminum chloride and crystalline aluminum chloride. The yield of polyaluminum chloride is too low and uneconomical; the crystallization of aluminum chloride by distillation or hydrogen chloride method has the problems of high energy consumption and complex operation.

[0010] In the present invention, the preparation method uses hydrochloric acid solution to acid-hydrolyze aluminum chloride waste liquid at least once. The preparation method is simple and has a high recovery rate. The prepared crystalline aluminum chloride has high purity and can directly meet the standard for external sale.

[0011] Preferably, the preparation method comprises the following steps:

[0012] (1) firstly subjecting the aluminum chloride waste liquid to a first acid hydrolysis using a hydrochloric acid solution, and separating the liquids to obtain an upper organic phase, an intermediate aluminum water phase, and a lower salt-containing aluminum water phase;

[0013] (2) The lower layer of aluminum water containing salt is filtered to obtain crystalline aluminum chloride and filtrate.

[0014] Preferably, the preparation method further comprises step (3): mixing the intermediate aluminum aqueous phase and the filtrate, adding hydrochloric acid solution and water, repeating step (2) after acidolysis and liquid separation, and the above process is carried out at least once (for example, 2 times, 3 times, 4 times, 5 times, 6 times, etc.).

[0015] In the present invention, the intermediate aluminum aqueous phase and the filtrate are mixed, and hydrochloric acid solution and water are added, and acid hydrolysis and liquid separation can be directly carried out, or the process can be applied to step (1), and further acid hydrolysis and liquid separation are carried out after mixing with a new batch of aluminum chloride waste liquid, so as to realize a continuous process.

[0016] In the present invention, the method further comprises step (3), which not only further recycles the waste liquid, but also takes into account the advantages of simple operation and does not lose the purity of the obtained crystalline aluminum chloride.

[0017] Preferably, the water in step (3) is first used to wash the upper organic phase, and then the recovered water is added to the system.

[0018] In the present invention, the washing water of the upper organic phase is transferred to the acid hydrolysis process, and the material balance can be achieved through simple operation.

[0019] Preferably, the mass concentration of the hydrochloric acid solution is 20%-30%, such as 22%, 24%, 26%, 28%, etc.

[0020] In the present invention, the mass concentration of the hydrochloric acid solution is controlled within a preferred range because the solubility of crystalline aluminum chloride in the hydrochloric acid solution is related to the concentration of hydrochloric acid. Within the preferred range, the solubility of crystalline aluminum chloride is very low, so that the crystalline aluminum chloride can be completely precipitated, and the concentration of hydrochloric acid can ensure that the acid hydrolysis is complete.

[0021] Preferably, the mass ratio of the aluminum chloride in the aluminum chloride waste liquid to the added hydrochloric acid solution is (3-10):1, wherein 3-10 can be 4, 5, 6, 7, 8, 9, etc.

[0022] In the present invention, the mass ratio of the aluminum chloride in the aluminum chloride waste liquid to the added hydrochloric acid solution is controlled within a preferred range to ensure that the acid hydrolysis can be carried out completely, and at the same time, liquid separation can be carried out to allow the crystallized aluminum chloride to precipitate.

[0023] Preferably, the mass ratio of aluminum chloride in the aluminum chloride waste liquid to the added water is (0.2-5):1, wherein 0.2-5 can be 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, etc.

[0024] In the present invention, the mass ratio of aluminum chloride in the aluminum chloride waste liquid to the added water is controlled within a preferred range, and the crystalline aluminum chloride is efficiently and conveniently prepared in combination with the hydrochloric acid solution.

[0025] Preferably, during the first acid hydrolysis, the mass ratio of aluminum chloride in the aluminum chloride waste liquid to the hydrochloric acid solution is 1:(3-10), wherein 3-10 can be 4, 5, 6, 7, 8, 9, etc.

[0026] Preferably, the preparation method further comprises step (4): recovering hydrogen chloride in the waste liquid after acid hydrolysis to obtain concentrated hydrochloric acid.

[0027] In the present invention, in a preferred embodiment, the hydrogen chloride in the waste liquid is further recovered to obtain concentrated hydrochloric acid for further utilization.

[0028] Preferably, the recovery method includes falling film absorption.

[0029] Preferably, the aluminum chloride waste liquid also includes hydrogen chloride.

[0030] Preferably, the aluminum chloride waste liquid originates from a mixed liquid produced by a ketone photoinitiator using aluminum chloride as a catalyst during the ketone production stage.

[0031] In the present invention, the preparation method is applicable to a mixed solution produced by using aluminum chloride as a catalyst in a Friedel-Crafts reaction. A typical but non-limiting example is a mixed solution containing aluminum chloride after the Friedel-Crafts reaction when preparing the photoinitiator 1173.

[0032] Preferably, the aluminum chloride waste liquid comprises a ketone photoinitiator, aluminum chloride, hydrogen chloride, an organic solvent and water.

[0033] In the present invention, the aluminum chloride waste liquid in the aluminum chloride waste liquid is subjected to the first acid hydrolysis using a hydrochloric acid solution, and the liquid is separated to obtain an upper organic phase, an intermediate aluminum water phase, and a lower saline aluminum water. Among them, the main components of the upper organic phase are organic solvents and ketone photoinitiators; the main components of the lower saline aluminum water are aluminum chloride, hydrogen chloride, and water; the intermediate aluminum water phase belongs to the transition layer, including ketone photoinitiators (with very little content), aluminum chloride, hydrogen chloride, organic solvents, and water, and will separate after standing for a long time. The present invention treats it separately to improve the yield and reduce the waste of raw materials.

[0034] Preferably, the ketone photoinitiator includes any one of photoinitiator 1173, photoinitiator CBP, photoinitiator OMBB, photoinitiator MBZ or photoinitiator 118, or a combination of at least two of them, wherein typical but non-limiting combinations include: a combination of photoinitiator 1173 and photoinitiator CBP, a combination of photoinitiator OMBB, photoinitiator MBZ and photoinitiator 118, a combination of photoinitiator 1173, photoinitiator CBP, photoinitiator OMBB, photoinitiator MBZ and photoinitiator 118, and the like.

[0035] Preferably, the mass ratio of the organic solvent to water is (0.5-2):1, wherein 0.5-2 can be 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, etc.

[0036] Preferably, the organic solvent comprises any one of benzene, chlorobenzene or toluene or a combination of at least two thereof, wherein typical but non-limiting combinations include: a combination of benzene and chlorobenzene, a combination of chlorobenzene and toluene, a combination of benzene, chlorobenzene and toluene, and the like.

[0037] Taking the total mass of the aluminum chloride waste liquid as 100%, the mass of the hydrogen chloride is 1%-30%, for example, 5%, 15%, 20%, 25%, etc.

[0038] Taking the total mass of the aluminum chloride waste liquid as 100%, the mass of the aluminum chloride is 5%-70%, for example, 5%, 15%, 20%, 25%, 35%, 45%, 55%, 65%, etc.

[0039] Preferably, based on the total mass of the intermediate aluminum water phase and the lower layer of salt-containing aluminum water as 100%, the mass of the hydrogen chloride is 5%-13%, for example, 6%, 7%, 8%, 9%, 10%, 11%, 12%, etc.

[0040] Preferably, based on the total mass of the intermediate aluminum water phase and the lower layer of salt-containing aluminum water being 100%, the mass of the aluminum chloride is 20%-30%, for example, 22%, 24%, 26%, 28%, etc.

[0041] In the present invention, the preparation method can process low-concentration aluminum chloride waste liquid with simple operation and achieve high recovery rate and high purity.

[0042] As a preferred technical solution, the preparation method comprises the following steps:

[0043] (1) firstly subjecting the aluminum chloride waste liquid to a first acid hydrolysis using a hydrochloric acid solution having a mass concentration of 20% to 30%, wherein the mass ratio of aluminum chloride in the aluminum chloride waste liquid to the hydrochloric acid solution is 1:(3-10), and separating the liquids to obtain an upper organic phase, an intermediate aluminum water phase, and a lower salt-containing aluminum water phase;

[0044] (2) filtering the lower layer of aluminum water containing salt to obtain crystalline aluminum chloride and filtrate;

[0045] (3) mixing the intermediate aluminum aqueous phase and the filtrate, washing the upper organic phase with water, adding hydrochloric acid solution and washing water of the upper organic phase, repeating step (2) after acid hydrolysis and separation, and performing the above process at least once to obtain crystalline aluminum chloride;

[0046] Wherein, the mass ratio of the aluminum chloride in the aluminum chloride waste liquid to the added hydrochloric acid solution is (3-10): 1;

[0047] The mass ratio of aluminum chloride in the aluminum chloride waste liquid to the added water is (0.2-5):1;

[0048] (4) collecting the crystalline aluminum chloride obtained in steps (2) and (3), and recovering the hydrogen chloride in the waste liquid after acid hydrolysis to obtain concentrated hydrochloric acid.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The preparation method of the present invention has a high recovery rate, and the obtained crystalline aluminum chloride has a high purity and can be directly sold (the purity standard for sale is ≥93%). In addition, compared with the high energy consumption of aluminum chloride crystallization by distillation, the complex operation of hydrogen chloride method and the inability to achieve material balance, the preparation method of the present invention can reduce energy consumption and cost, achieve material balance, increase profits and simplify operations.

[0051] (2) The recovery rate of the crystalline aluminum chloride obtained by the preparation method of the present invention is above 90%, and the purity is above 93%. DETAILED DESCRIPTION

[0052] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0053] In a specific embodiment of the present invention, the aluminum chloride waste liquid originates from a mixed liquid produced by a ketone photoinitiator using aluminum chloride as a catalyst in the ketone production stage; specifically, it includes 1g of ketone photoinitiator, 25g of aluminum chloride, 10g of hydrogen chloride, 65g of organic solvent and 65g of water.

[0054] Among them, the ketone photoinitiator includes but is not limited to any one of photoinitiator 1173, photoinitiator CBP, photoinitiator OMBB, photoinitiator MBZ or photoinitiator 118, or a combination of at least two of them. In a specific embodiment of the present invention, the ketone photoinitiator is selected from photoinitiator 1173.

[0055] The organic solvent includes but is not limited to any one of benzene, chlorobenzene or toluene or a combination of at least two thereof. In a specific embodiment of the present invention, the organic solvent is selected from benzene.

[0056] Example 1

[0057] This embodiment provides a method for preparing crystalline aluminum chloride, the preparation method comprising the following steps:

[0058] (1) firstly subjecting the aluminum chloride waste liquid to a first acid hydrolysis using a hydrochloric acid solution having a mass concentration of 25%, wherein the mass ratio of aluminum chloride in the aluminum chloride waste liquid to the hydrochloric acid solution is 1:6, and separating the liquids to obtain an upper organic phase, an intermediate aluminum water phase, and a lower salt-containing aluminum water phase;

[0059] (2) filtering the lower layer of aluminum water containing salt to obtain crystalline aluminum chloride and filtrate;

[0060] (3) mixing the intermediate aluminum aqueous phase and the filtrate, washing the upper organic phase with water, adding hydrochloric acid solution and the washing water of the upper organic phase, repeating step (2) after acid hydrolysis and separation, and performing the above process three times to obtain crystalline aluminum chloride;

[0061] Wherein, the mass ratio of aluminum chloride in the aluminum chloride waste liquid to the added hydrochloric acid solution is 5:1;

[0062] The mass ratio of aluminum chloride in the aluminum chloride waste liquid to the added water is 1:1;

[0063] (4) collecting the crystalline aluminum chloride obtained in steps (2) and (3), and recovering the hydrogen chloride in the waste liquid after acid hydrolysis to obtain concentrated hydrochloric acid.

[0064] Example 2

[0065] This embodiment provides a method for preparing crystalline aluminum chloride, the preparation method comprising the following steps:

[0066] (1) firstly subjecting the aluminum chloride waste liquid to a first acid hydrolysis using a hydrochloric acid solution having a mass concentration of 30%, wherein the mass ratio of aluminum chloride in the aluminum chloride waste liquid to the hydrochloric acid solution is 1:10, and separating the liquids to obtain an upper organic phase, an intermediate aluminum water phase, and a lower salt-containing aluminum water phase;

[0067] (2) filtering the lower layer of aluminum water containing salt to obtain crystalline aluminum chloride and filtrate;

[0068] (3) mixing the intermediate aluminum aqueous phase and the filtrate, washing the upper organic phase with water, adding hydrochloric acid solution and the washing water of the upper organic phase, repeating step (2) after acid hydrolysis and separation, and performing the above process 4 times to obtain crystalline aluminum chloride;

[0069] Wherein, the mass ratio of aluminum chloride in the aluminum chloride waste liquid to the added hydrochloric acid solution is 3:1;

[0070] The mass ratio of aluminum chloride in the aluminum chloride waste liquid to the added water is 0.25:1;

[0071] (4) collecting the crystalline aluminum chloride obtained in steps (2) and (3), and recovering the hydrogen chloride in the waste liquid after acid hydrolysis to obtain concentrated hydrochloric acid.

[0072] Example 3

[0073] This embodiment provides a method for preparing crystalline aluminum chloride, the preparation method comprising the following steps:

[0074] (1) firstly subjecting the aluminum chloride waste liquid to a first acid hydrolysis using a hydrochloric acid solution having a mass concentration of 20%, wherein the mass ratio of aluminum chloride in the aluminum chloride waste liquid to the hydrochloric acid solution is 1:3, and separating the liquids to obtain an upper organic phase, an intermediate aluminum water phase, and a lower salt-containing aluminum water phase;

[0075] (2) filtering the lower layer of aluminum water containing salt to obtain crystalline aluminum chloride and filtrate;

[0076] (3) mixing the intermediate aluminum aqueous phase and the filtrate, washing the upper organic phase with water, adding hydrochloric acid solution and the washing water of the upper organic phase, repeating step (2) after acid hydrolysis and separation, and performing the above process twice to obtain crystalline aluminum chloride;

[0077] Wherein, the mass ratio of aluminum chloride in the aluminum chloride waste liquid to the added hydrochloric acid solution is 10:1;

[0078] The mass ratio of aluminum chloride in the aluminum chloride waste liquid to the added water is 5:1;

[0079] (4) collecting the crystalline aluminum chloride obtained in steps (2) and (3), and recovering the hydrogen chloride in the waste liquid after acid hydrolysis to obtain concentrated hydrochloric acid.

[0080] Embodiment 4-7

[0081] The difference between Examples 4-7 and Example 1 is that the concentrations of the hydrochloric acid solutions are 15% (Example 4), 20% (Example 5), 30% (Example 6) and 35% (Example 7), respectively, and the rest are the same as Example 1.

[0082] Embodiment 8-9

[0083] The difference between Examples 8-9 and Example 1 is that in step (1), the mass ratio of aluminum chloride in the aluminum chloride waste liquid to the hydrochloric acid solution is 1:2 (Example 8) and 1:12 (Example 9), and the rest is the same as Example 1.

[0084] Embodiment 10-11

[0085] The difference between Examples 10-11 and Example 1 is that in step (3), the mass ratio of the aluminum chloride in the aluminum chloride waste liquid to the added hydrochloric acid solution is 2:1 (Example 10) and 12:1 (Example 11), and the rest is the same as Example 1.

[0086] Examples 12-13

[0087] The difference between Examples 12-13 and Example 1 is that in step (3), the mass ratio of aluminum chloride in the aluminum chloride waste liquid to the added water is 0.1:1 (Example 12) and 6:1 (Example 13), and the rest is the same as Example 1.

[0088] Comparative Example 1

[0089] The difference between this comparative example and Example 1 is that the hydrochloric acid solution is replaced by hydrogen chloride gas, and the rest is the same as Example 1.

[0090] Performance Testing

[0091] The crystalline aluminum chloride obtained by the preparation method described in Examples 1-13 and Comparative Example 1 was tested for recovery and purity as follows according to the standard of HG / T3251-2018.

[0092] The test results are summarized in Table 1.

[0093] Table 1

[0094] Recovery rate (%) purity(%) Example 1 92 98 Example 2 91 96 Example 3 90 95 Example 4 90.6 93 Example 5 92 96 Example 6 91 97 Example 7 90 93 Example 8 91.2 95.6 Example 9 90.5 96.7 Example 10 90.3 95.6 Embodiment 11 90.8 96.7 Example 12 91.5 95.2 Embodiment 13 91.2 97.2 Comparative Example 1 88 93.5

[0095] Analysis of the data in Table 1 shows that the recovery rate of the crystalline aluminum chloride obtained by the preparation method of the present invention is above 90%, and the purity is above 93%; the preparation method of the present invention has a high recovery rate, and the obtained crystalline aluminum chloride has a high purity and can be directly sold (the purity standard for sale is ≥93%). In addition, compared with the high energy consumption of crystallizing aluminum chloride by distillation, the complex operation of the hydrogen chloride method and the inability to achieve material balance, the preparation method of the present invention can reduce energy consumption and cost, achieve material balance, increase profits and simplify operations.

[0096] Analysis of Comparative Example 1 and Example 1 shows that the performance of Comparative Example 1 is not as good as that of Example 1, which proves that the use of hydrochloric acid solution in the preparation method of the present invention is more conducive to the preparation of crystalline aluminum chloride than passing hydrogen chloride. In addition, material balance and simplified operation can be achieved.

[0097] Analysis of Examples 4-7 shows that Examples 4 and 7 are not as good as Examples 5-6, which proves that controlling the mass concentration of the hydrochloric acid solution in the preparation method of the present invention within the range of 20%-30% is more conducive to the preparation of crystalline aluminum chloride.

[0098] Analysis of Examples 8-9 and Example 1 shows that the performance of Examples 8-9 is not as good as that of Example 1, which proves that controlling the mass ratio of aluminum chloride to hydrochloric acid solution in the aluminum chloride waste liquid within a preferred range in the preparation method of the present invention is more conducive to the preparation of crystalline aluminum chloride.

[0099] Analysis of Examples 10-11 and Example 1 shows that the performance of Examples 10-11 is not as good as that of Example 1, which proves that controlling the mass ratio of aluminum chloride in the aluminum chloride waste liquid to the added hydrochloric acid solution within a preferred range in the preparation method of the present invention is more conducive to the preparation of crystalline aluminum chloride.

[0100] Analysis of Examples 12-13 and Example 1 shows that the performance of Examples 12-13 is not as good as that of Example 1, which proves that controlling the mass ratio of aluminum chloride in the aluminum chloride waste liquid to the added water within a preferred range in the preparation method of the present invention is more conducive to the preparation of crystalline aluminum chloride.

[0101] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing crystalline aluminum chloride, characterized in that: The preparation method comprises the following steps: subjecting aluminum chloride waste liquid to at least one acid hydrolysis using a hydrochloric acid solution to obtain the crystalline aluminum chloride.

2. The preparation method according to claim 1, characterized in that: The preparation method comprises the following steps: (1) firstly subjecting the aluminum chloride waste liquid to a first acid hydrolysis using the hydrochloric acid solution, and separating the liquids to obtain an upper organic phase, an intermediate aluminum water phase, and a lower salt-containing aluminum water phase; (2) The lower layer of aluminum water containing salt is filtered to obtain the crystalline aluminum chloride and filtrate.

3. The preparation method according to claim 2, characterized in that: The preparation method further comprises step (3): mixing the intermediate aluminum aqueous phase and the filtrate, adding the hydrochloric acid solution and water, repeating step (2) after acid hydrolysis and liquid separation, and the above process is performed at least once.

4. The preparation method according to claim 3, characterized in that: In step (3), the water is first used to wash the upper organic phase, and then the recovered water is added to the system.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The mass concentration of the hydrochloric acid solution is 20%-30%.

6. The preparation method according to claim 3, characterized in that: The mass ratio of the aluminum chloride in the aluminum chloride waste liquid to the added hydrochloric acid solution is (3-10):1; Preferably, the mass ratio of the aluminum chloride in the aluminum chloride waste liquid to the added water is (0.2-5):

1.

7. The preparation method according to claim 2, characterized in that: During the first acid hydrolysis, the mass ratio of the aluminum chloride in the aluminum chloride waste liquid to the hydrochloric acid solution is 1:(3-10).

8. The preparation method according to any one of claims 2 to 4, characterized in that: The preparation method further comprises step (4): recovering hydrogen chloride in the waste liquid after acid hydrolysis to obtain concentrated hydrochloric acid.

9. The preparation method according to any one of claims 1 to 8, characterized in that: The aluminum chloride waste liquid also includes hydrogen chloride; Preferably, the aluminum chloride waste liquid originates from a mixed liquid produced by a ketone photoinitiator using aluminum chloride as a catalyst in the ketone production stage; Preferably, the aluminum chloride waste liquid comprises a ketone photoinitiator, aluminum chloride, hydrogen chloride, an organic solvent and water; Preferably, the ketone photoinitiator includes any one or a combination of at least two of photoinitiator 1173, photoinitiator CBP, photoinitiator OMBB, photoinitiator MBZ or photoinitiator 118; Preferably, the organic solvent comprises any one of benzene, chlorobenzene or toluene, or a combination of at least two thereof; Preferably, the mass of the hydrogen chloride is 5%-13% based on the total mass of the intermediate aluminum water phase and the lower layer of salt-containing aluminum water being 100%; Preferably, based on the total mass of the intermediate aluminum water phase and the lower layer of salt-containing aluminum water being 100%, the mass of the aluminum chloride is 20%-30%.

10. The preparation method according to claim 1, characterized in that: The preparation method comprises the following steps: (1) firstly subjecting the aluminum chloride waste liquid to a first acid hydrolysis using the hydrochloric acid solution having a mass concentration of 20% to 30%, wherein the mass ratio of aluminum chloride in the aluminum chloride waste liquid to the hydrochloric acid solution is 1:(3-10), and separating the liquids to obtain an upper organic phase, an intermediate aluminum water phase, and a lower salt-containing aluminum water phase; (2) filtering the lower layer of aluminum water containing salt to obtain the crystalline aluminum chloride and filtrate; (3) mixing the intermediate aluminum aqueous phase and the filtrate, washing the upper organic phase with water, adding the hydrochloric acid solution and the washing water of the upper organic phase, repeating step (2) after acid hydrolysis and separation, and performing the above process at least once to obtain the crystalline aluminum chloride; Wherein, the mass ratio of the aluminum chloride in the aluminum chloride waste liquid to the added hydrochloric acid solution is (3-10): 1; The mass ratio of aluminum chloride in the aluminum chloride waste liquid to the added water is (0.2-5):1; (4) collecting the crystalline aluminum chloride obtained in steps (2) and (3), and recovering the hydrogen chloride in the waste liquid after acid hydrolysis to obtain concentrated hydrochloric acid.