Preparation process of hybrid zinc aluminate synthesized by using solid waste sodium tetrachloroaluminate

Abstract

The application relates to a preparation process of synthesizing hybrid zinc aluminate by using solid waste sodium tetrachloroaluminate, and belongs to the technical field of chemical dangerous waste treatment, and comprises the following synthesis steps: S1, zinc compounds are added in water, and the zinc compounds are completely dissolved or uniformly dispersed; S2, solid waste sodium tetrachloroaluminate is added, and the solid waste sodium tetrachloroaluminate is completely dissolved and reacted by continuing to stir; S3, an oxidizing agent is added, and the reaction is continued by keeping warm and stirring, then filtration is carried out, and the phosphorus content in the filtrate is detected; S4, after the phosphorus content is qualified, sodium hydroxide solution is added into the filtrate, the pH value is controlled, and white zinc aluminate precursor precipitate is generated; S5, the white zinc aluminate precursor precipitate is transferred into a high-pressure reaction kettle to carry out hydrothermal reaction, and hybrid zinc aluminate liquid is generated; S6, negative pressure suction filtration is carried out, the obtained filter solid is washed by using deionized water, the filter solid is subjected to spray drying, and solid hybrid zinc aluminate is obtained. The application fully utilizes aluminum resources in the solid waste sodium tetrachloroaluminate, and total phosphorus impurities in the solid waste sodium tetrachloroaluminate are also utilized to generate effective components, so that waste is turned into treasure.

Description

Technical Field

[0001] This invention belongs to the field of chemical hazardous waste treatment technology, specifically relating to a preparation process for synthesizing hybrid zinc aluminate using sodium tetrachloroaluminate from solid waste. Background Technology

[0002] Sodium tetrachloroaluminate, a solid waste, is generated during the preparation of methyldichlorophosphine, a core intermediate involved in the production of the agricultural herbicide glufosinate. The preparation of methyldichlorophosphine mainly employs the ternary complex method and the alkylaluminum method. Both methods generate large quantities of sodium tetrachloroaluminate during the preparation process. This sodium tetrachloroaluminate also contains small amounts of organophosphine and inorganic phosphorus impurities (hereinafter referred to as total phosphorus impurities). During storage, this solid waste absorbs moisture from the air, releasing large amounts of heat and hydrogen chloride gas, exhibiting strong acidity, thus posing certain hazards and being difficult to handle. Since the advent of methyldichlorophosphine synthesis technology, sodium tetrachloroaluminate waste salt has been a persistent and insurmountable challenge for related industries. Currently, the production volume of this solid waste salt is enormous, and due to the lack of technologically mature, economically cost-effective, and efficient disposal methods, it is often discarded or buried, resulting in the waste and non-renewable use of aluminum resources. Furthermore, because this solid waste is highly acidic and contains organophosphine compounds, burying it severely pollutes the soil and groundwater, adversely affecting environmental health and safety. This wastes resources and pollutes the environment, which is completely inconsistent with the concept of green development today.

[0003] Existing technologies disclose methods for treating this solid waste, sodium tetrachloroaluminate, by preparing polyaluminum chloride water purifiers, such as patents CN 108238621A, CN 221191576U, CN 105217667 B, CN 114671447 A, CN 115253915 B, CN 117886347 A, and CN 117303422 A. However, all of these methods suffer from high safety risks, complex processes, high costs, and low total phosphorus impurity removal efficiency. The resulting polyaluminum chloride has low economic value, an unreasonable input-output ratio, and is not suitable for large-scale industrial production. Summary of the Invention

[0004] This invention provides a preparation process for synthesizing hybrid zinc aluminate using sodium tetrachloroaluminate from solid waste. This invention utilizes the aluminum and phosphorus elements in sodium tetrachloroaluminate from solid waste, thus solving the problems of resource waste and environmental pollution.

[0005] The technical solution of the present invention: A preparation process for synthesizing hybrid zinc aluminate using sodium tetrachloroaluminate from solid waste includes the following synthesis steps: S1. Add zinc compound to water and stir until the zinc compound is completely dissolved or evenly dispersed; S2. Add solid waste sodium tetrachloroaluminate to the zinc compound that has been completely dissolved or evenly dispersed in step S1, and continue stirring to completely dissolve and react the solid waste sodium tetrachloroaluminate to obtain a reaction solution; The chemical reaction equation that occurs in step S2 is as follows: CH3Cl2P + 2H2O → CH3P(O)OH2+ 2HCl PCl3 + 3H2O → H3PO3 + 3HCl NaAlCl4+ 6H2O → AlCl3﹒6H2O + NaCl S3. Add an oxidant to the reaction solution in step S2, continue to keep warm and stir the reaction, filter, and detect the phosphorus content in the filtrate; The chemical reaction equation that occurs in step S3 is as follows: Na₂CO₄ + H₂O → Na₂CO₃ + H₂O₂ CH3P(O)OH2+ H2O2→CH3P(O)(OH)2+ H2O H3PO3 + H2O2 → H3PO4 + H2O CH3P(O)(OH)2+ Zn 2+ → CH3P(O)(O)2Zn↓ H3PO4+ Zn 2+ → Zn3(PO4)2↓ Na₂CO₃ + HCl → NaCl + H₂O S4. After the phosphorus content in the filtrate is found to be qualified in step S3, sodium hydroxide solution is added to the filtrate to control the pH value. The reaction is continued by stirring to generate a white zinc aluminate precursor precipitate. The chemical reaction equation that occurs in step S4 is as follows: AlCl3·6H2O + Zn 2+ + NaOH → ZnAl2O4↓ + NaCl S5. The white zinc aluminate precursor precipitate generated in step S4 is transferred to a high-pressure reactor for hydrothermal reaction. The temperature is raised to 130°C and the reaction is maintained for 1.5-2 hours. This step causes zinc aluminate to form a defect spinel structure, and the defect is the total phosphorus zinc salt, which generates hybrid zinc aluminate liquid. S6. The hybrid zinc aluminate liquid generated in step S5 is filtered under negative pressure. The resulting filter solid is washed with deionized water and dried to obtain solid hybrid zinc aluminate.

[0006] The filtrate produced after filtration is a sodium chloride solution, which can be directly processed using existing technologies. If the sodium chloride solution is concentrated and crystallized to meet the requirements of the national standard QB / T5270-2018 for caustic soda salt used in ion-exchange membranes, it can be circulated as a by-product. This part of the process falls within the scope of existing technology and is not within the scope of the claims of this invention.

[0007] Preferably, the zinc compound in step S1 is one of zinc chloride, zinc sulfate, zinc carbonate, and zinc oxide; in step S1, the zinc compound is zinc chloride or zinc sulfate, and the mixture is stirred to completely dissolve the zinc compound in water; in step S1, the zinc compound is zinc carbonate or zinc oxide, and the mixture is stirred to evenly disperse the zinc compound in water. The water mentioned in step S1 is deionized water; In step S1, the mass ratio of water to zinc compound is 1:0.06~0.25.

[0008] Preferably, the solid waste sodium tetrachloroaluminate mentioned in step S2 is a solid waste salt generated during the preparation of methylphosphine dichloride using the ternary complex method or the alkylaluminum method; The solid waste sodium tetrachloroaluminate contains the following components in weight percentage: 65%~70% sodium tetrachloroaluminate, 25%~30% and 3%~5% total phosphorus impurities; The temperature during the complete dissolution of sodium tetrachloroaluminate in the solid waste is controlled between 80℃ and 100℃. The mass ratio of water to solid waste sodium tetrachloroaluminate is 1:0.3~0.4.

[0009] Preferably, the total phosphorus impurities in step S2 include methylphosphine dichloride and phosphorus trichloride; Preferably, the oxidant in step S3 is sodium percarbonate; The amount of oxidant added in step S3 is 1% to 5% of the weight of sodium tetrachloroaluminate in the solid waste; One function of the oxidant is that sodium percarbonate dissolves in the material to generate hydrogen peroxide, which reacts with total phosphorus impurities to oxidize trivalent total phosphorus to pentavalent state, thereby ensuring that pentavalent total phosphorus reacts with zinc compounds to form total phosphorus zinc salt colloidal precipitate; another function is that sodium percarbonate dissolves in the material and reacts with hydrogen chloride in the material to generate sodium chloride, thereby regulating the pH value of the material between 2 and 3.

[0010] The temperature for heat preservation in step S3 is 80℃~100℃, and the stirring time is 1~3 hours, resulting in the precipitation of a white colloidal precipitate.

[0011] Preferably, the amount of oxidant added in step S3 is 2.5% to 3.5% of the weight of sodium tetrachloroaluminate in solid waste; the stirring time in step S3 is 1 to 1.5 hours.

[0012] Preferably, the method for detecting phosphorus content in step S3 is to filter the reaction solution after the incubation and stirring reaction is completed, and determine the phosphorus content of the filtrate. If the total phosphorus content in the filtrate is ≤8ppm, it is qualified and the next step is performed; if the total phosphorus content in the filtrate is >8ppm, it is unqualified, and the filtrate continues to undergo the incubation and stirring reaction in step S3 until it is qualified.

[0013] Preferably, the sodium hydroxide solution in step S4 is a 32% sodium hydroxide aqueous solution; the pH is controlled to be 7-9.

[0014] Preferably, the pH is controlled to be 7.5~8.5 in step S4.

[0015] Preferably, in step S6, the pressure of negative pressure filtration is 0.08~0.09 MPa, the mass ratio of filter solid to deionized water is 1:2, and the filter solid is spray-dried at a temperature of 100~110℃. Stop washing when the sodium chloride content in the filter solids is ≤0.05%.

[0016] Zinc aluminate precipitate is generated by reacting a zinc compound with sodium tetrachloroaluminate. Simultaneously, the zinc compound reacts with total phosphorus impurities in the sodium tetrachloroaluminate to form total phosphorus zinc salt, which co-precipitates with the zinc aluminate, ultimately producing the target product, hybrid zinc aluminate. Zinc aluminate belongs to the category of inorganic salt chemical synthesis and is currently produced and applied in the market. As a flame retardant, it possesses four major functions: flame retardancy, smoke suppression, drip prevention, and corrosion prevention. When applied to PVC plastics, it can efficiently and quickly absorb the toxic hydrogen chloride gas produced during PVC combustion, reducing smoke generation. It can completely replace existing zinc borate and aluminum hydroxide flame retardants and smoke suppressants, and 60% replace the expensive antimony trioxide flame retardant currently on the market. This product does not contain heavy metal elements restricted by the EU and is a novel inorganic flame retardant that meets current green and environmentally friendly requirements, with broad application prospects. This invention utilizes this solid waste sodium tetrachloroaluminate to synthesize a high-value-added target product, hybrid zinc aluminate. Furthermore, the synthesis process simultaneously utilizes aluminum and phosphorus elements from the solid waste sodium tetrachloroaluminate, solving the problems of resource waste and environmental pollution. The target product, hybrid zinc aluminate, can be used as a flame retardant in applications requiring fire resistance and flame retardancy in rubber and plastics. Specifically, it offers the following beneficial effects: 1. This invention makes full use of the aluminum resources in solid waste sodium tetrachloroaluminate, and at the same time, the total phosphorus impurities in solid waste sodium tetrachloroaluminate are also utilized to generate effective components. One process maximizes the utilization of two elements, aluminum and phosphorus, and realizes the efficient and high-value recycling of process raw materials, turning waste into treasure, and reflecting atom economy.

[0017] 2. In this invention, the total phosphorus in the solid waste sodium tetrachloroaluminate is no longer regarded as an impurity, but is transformed into a valuable raw material. This eliminates the complex process of removing total phosphorus impurities in traditional processes, saving both resources and energy consumption.

[0018] 3. Comparison of the target product of this invention, hybrid zinc aluminate, with conventional commercially available zinc aluminate (CAS 12068-53-0) in flame retardant applications: The hybrid zinc aluminate of this invention not only possesses the same four flame-retardant properties as traditional zinc aluminate, but also, due to its content of total phosphorus and zinc salts, has the function of rapidly catalyzing the carbonization of plastic resins during flame combustion. Therefore, its flame-retardant efficiency is significantly better than that of traditional commercially available zinc aluminate flame retardants. Furthermore, since the hybrid zinc aluminate of this invention is prepared using solid waste, the process is simple and the cost is low, giving it a significant price competitive advantage compared to traditional commercially available zinc aluminate. It truly achieves high quality at a low price, resulting in considerable economic benefits.

[0019] This invention solves the problem of waste salt treatment in the production of methyl dichlorophosphine and realizes high-value-added recycling, which has greatly promoted the green, large-scale and economical production of glufosinate, resulting in significant social and economic benefits. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative design and practice are within the scope of protection of the present invention.

[0021] The preparation process of the hybrid zinc aluminate of the present invention is described in the examples. In order to compare the flame retardant performance with that of conventional commercially available zinc aluminate, conventional commercially available zinc aluminate was selected as the comparative example.

[0022] Example 1

[0023] Add 138 g of zinc chloride to 1000 g of deionized water and stir until completely dissolved. Then slowly add 384 g of sodium tetrachloroaluminate (solid waste). After complete dissolution, maintain the temperature at 90°C with stirring. Dissolve 13.4 g of sodium percarbonate in 600 g of deionized water to form a solution. Slowly add this solution to the above materials, maintaining the temperature at 90°C throughout the addition process. After all the solution is added, continue stirring and maintaining the temperature for 1.5 hours. White flocculent matter is observed to form. At this point, take a sample and filter it. The total phosphorus content in the filtrate is determined to be 7.2 ppm; the pH value of the filtrate is 2, which is considered acceptable.

[0024] 741 grams of a 32% sodium hydroxide solution was slowly added to the above materials while stirring continuously. A large amount of white zinc aluminate precursor precipitate was formed. The pH of the solution at this point was measured to be 8.5, which was deemed acceptable.

[0025] The above materials were transferred to a high-pressure reactor for hydrothermal reaction, heated to 130℃, and held for 2 hours. The reacted material was then subjected to negative pressure filtration, controlling the vacuum pressure at 0.08~0.09 MPa. The resulting filter solid was washed with 780 g of deionized water, followed by negative pressure filtration, controlling the vacuum pressure at 0.08~0.09 MPa. This washing process was repeated three times. The resulting filter solid was found to have a sodium chloride content of 0.045%, which was deemed acceptable. The filter solid was then spray-dried at 110℃ to obtain 386 g of the final product, hybrid zinc aluminate. Inductively coupled plasma optical emission spectrometry (ICP-OES) determined its purity and impurity percentage to be: zinc aluminate 94.16%; total phosphorus and zinc salts 3.22%.

[0026] Example 2

[0027] Add 166g of anhydrous zinc sulfate to 1000g of deionized water and stir until completely dissolved. Then slowly add 384g of sodium tetrachloroaluminate (solid waste). After complete dissolution, maintain the temperature at 90℃ and stir. Dissolve 11.5g of sodium percarbonate in 600g of deionized water to form a solution. Slowly add this solution to the above materials, maintaining the temperature at 90℃ throughout the addition process. After all the solution is added, continue stirring and maintaining the temperature for 1.5 hours. White flocculent matter is observed to form. At this point, take a sample and filter it. The total phosphorus content in the filtrate is determined to be 8ppm; the pH value of the filtrate is 2, which is considered acceptable.

[0028] 724 grams of a 32% sodium hydroxide solution was slowly added to the above materials while stirring continuously. A large amount of white zinc aluminate precursor precipitate was formed. The pH of the solution at this point was measured to be 8.2, which was deemed acceptable.

[0029] The above materials were transferred to a high-pressure reactor for hydrothermal reaction, heated to 130℃, and held for 2 hours. The reacted material was then subjected to negative pressure filtration, controlling the vacuum pressure at 0.08~0.09 MPa. The resulting filter solid was washed with 750 g of deionized water, followed by negative pressure filtration, controlling the vacuum pressure at 0.08~0.09 MPa. This washing process was repeated three times. The resulting filter solid was found to have a sodium chloride content of 0.045%, which was deemed acceptable. The filter solid was then spray-dried at 110℃ to obtain 375 g of the final product, hybrid zinc aluminate. Its purity and impurity percentage were determined by inductively coupled plasma optical emission spectrometry (ICP-OES): zinc aluminate 94.52%; total phosphorus and zinc salts 3.05%.

[0030] Example 3

[0031] Add 128 g of zinc carbonate to 1000 g of deionized water and stir to disperse it evenly. Then slowly add 384 g of sodium tetrachloroaluminate (solid waste). After complete dissolution, keep the mixture at 90°C with stirring. Dissolve 9.6 g of sodium percarbonate in 600 g of deionized water to form a solution. Slowly add this solution to the above materials while maintaining the temperature at 90°C throughout the addition process. After all the solution has been added, continue stirring and maintaining the temperature for 1.5 hours. White flocculent matter was observed to form. At this point, a sample was taken and filtered. The total phosphorus content in the filtrate was determined to be 6.9 ppm. The pH value of the filtrate was determined to be 3, which was considered acceptable.

[0032] 651 g of a 32% sodium hydroxide solution was slowly added to the above materials while stirring continuously, resulting in the formation of a large amount of white zinc aluminate precursor precipitate. The pH of the solution at this point was measured to be 8.5, which was deemed acceptable.

[0033] The above materials were transferred to a high-pressure reactor for hydrothermal reaction, heated to 130℃, and held for 2 hours. The reacted material was then subjected to negative pressure filtration, controlling the vacuum pressure at 0.08~0.09 MPa. The resulting filter solid was washed with 780 g of deionized water, followed by negative pressure filtration, controlling the vacuum pressure at 0.08~0.09 MPa. This washing process was repeated three times. The resulting filter solid was found to contain 0.045% sodium chloride, which was deemed acceptable. The filter solid was then spray-dried at 110℃ to obtain 388 g of the final product, hybrid zinc aluminate. Its purity and impurity percentage were determined by inductively coupled plasma optical emission spectrometry (ICP-OES): zinc aluminate 95.12%; total phosphorus and zinc salts 3.85%.

[0034] Example 4

[0035] Add 82 g of zinc oxide to 1000 g of deionized water and stir to disperse it evenly. Then slowly add 384 g of sodium tetrachloroaluminate and stir at 90°C until completely dissolved. Dissolve 9.6 g of sodium percarbonate in 600 g of deionized water to form a solution. Slowly add this solution to the above materials while maintaining the temperature at 90°C throughout the addition process. After all the solution is added, continue stirring and reacting for 1.5 hours. White flocculent matter is observed to form. At this point, take a sample and filter it. The total phosphorus content in the filtrate is determined to be 7.0 ppm. The pH value of the filtrate is 3, which is considered acceptable.

[0036] 648 grams of a 32% sodium hydroxide solution was slowly added to the above materials while stirring continuously. A large amount of white zinc aluminate precursor precipitate was formed. The pH of the solution at this point was measured to be 8.5, which was deemed acceptable.

[0037] The above materials were transferred to a high-pressure reactor for hydrothermal reaction, heated to 130℃, and held for 2 hours. The reacted material was then subjected to negative pressure filtration, controlling the vacuum pressure at 0.08~0.09 MPa. The resulting filter solid was washed with 750 g of deionized water, followed by negative pressure filtration, controlling the vacuum pressure at 0.08~0.09 MPa. This washing process was repeated three times. The resulting filter solid was found to have a sodium chloride content of 0.045%, which was deemed acceptable. The filter solid was then spray-dried at 110℃ to obtain 369 g of the final product, hybrid zinc aluminate. Its purity and impurity percentage were determined by inductively coupled plasma optical emission spectrometry (ICP-OES): zinc aluminate 95.06%; total phosphorus and zinc salts 3.15%.

[0038] Application examples Solid hybrid zinc aluminate prepared in Examples 1-4 of this invention and commercially available zinc aluminate in comparative proportions were mixed with PVC resin, calcium carbonate powder, terephthalic acid plasticizer, calcium-zinc heat stabilizer, and antimony trioxide (Sb₂O₃) flame retardant in specific ratios and extruded to produce PVC plastic. Zinc aluminate has high thermal stability, typically ≥400℃, therefore, special control of the plasticizing temperature during extrusion is not necessary; conventional extrusion processes can be used, with the plasticizing temperature controlled at 170±2℃ and the screw speed controlled at 60 rpm.

[0039] Table 1: Comparison of flame retardant properties of Example 1-Examples with conventional commercially available zinc aluminate in PVC plastics Note: Comparative example: Commercially available zinc aluminate (CAS 12068-53-0), industrial grade, 98% purity.

[0040] As shown in Table 1, under the premise of the same amount of additive, the PVC plastics prepared by Examples 1 to 4 all have a higher flame retardant oxygen index than the PVC plastics prepared by the comparative example. This indicates that the hybrid zinc aluminate prepared by the present invention has a higher flame retardant efficiency than conventional commercially available zinc aluminate.

[0041] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A preparation process for synthesizing hybrid zinc aluminate using sodium tetrachloroaluminate from solid waste, characterized in that, The synthesis steps include the following: S1. Add zinc compound to water and stir until the zinc compound is completely dissolved or evenly dispersed; S2. Add solid waste sodium tetrachloroaluminate to the zinc compound that has been completely dissolved or evenly dispersed in step S1, and continue stirring to completely dissolve and react the solid waste sodium tetrachloroaluminate to obtain a reaction solution; S3. Add an oxidant to the reaction solution in step S2, continue to keep warm and stir the reaction, filter, and detect the phosphorus content in the filtrate; S4. After the phosphorus content in the filtrate is found to be qualified in step S3, sodium hydroxide solution is added to the filtrate to control the pH value. The reaction is continued by stirring to generate a white zinc aluminate precursor precipitate. S5. The white zinc aluminate precursor precipitate generated in step S4 is transferred to a high-pressure reactor for hydrothermal reaction to generate hybrid zinc aluminate liquid. S6. The hybrid zinc aluminate liquid generated in step S5 is filtered under negative pressure. The resulting filter solid is washed with deionized water and dried to obtain solid hybrid zinc aluminate.

2. The preparation process for synthesizing hybrid zinc aluminate using sodium tetrachloroaluminate from solid waste according to claim 1, characterized in that, The zinc compound mentioned in step S1 is one of zinc chloride, zinc sulfate, zinc carbonate, and zinc oxide; In step S1, the zinc compound is zinc chloride or zinc sulfate, and the mixture is stirred to completely dissolve the zinc compound in water; in step S1, the zinc compound is zinc carbonate or zinc oxide, and the mixture is stirred to evenly disperse the zinc compound in water. The water mentioned in step S1 is deionized water; In step S1, the mass ratio of water to zinc compound is 1:0.06~0.

25.

3. The preparation process for synthesizing hybrid zinc aluminate using sodium tetrachloroaluminate from solid waste according to claim 1, characterized in that, The solid waste sodium tetrachloroaluminate mentioned in step S2 is a solid waste salt generated during the preparation of methylphosphine dichloride using the ternary complex method or the alkylaluminum method; The solid waste sodium tetrachloroaluminate contains the following components in weight percentage: 65%~70% sodium tetrachloroaluminate, 25%~30% sodium chloride and 3%~5% total phosphorus impurities; The temperature during the complete dissolution of sodium tetrachloroaluminate in the solid waste is controlled between 80℃ and 100℃. The mass ratio of water to solid waste sodium tetrachloroaluminate is 1:0.3~0.

4.

4. The preparation process for synthesizing hybrid zinc aluminate using sodium tetrachloroaluminate from solid waste according to claim 3, characterized in that, The total phosphorus impurities in step S2 include methylphosphine dichloride and phosphorus trichloride; The oxidant mentioned in step S3 is sodium percarbonate; The amount of oxidant added in step S3 is 1% to 5% of the weight of sodium tetrachloroaluminate in the solid waste; The temperature for heat preservation in step S3 is 80℃~100℃, and the stirring time is 1~3 hours.

5. The preparation process for synthesizing hybrid zinc aluminate using sodium tetrachloroaluminate from solid waste according to claim 4, characterized in that, The amount of oxidant added in step S3 is 2.5% to 3.5% of the weight of sodium tetrachloroaluminate in solid waste; the stirring time in step S3 is 1 to 1.5 hours.

6. The preparation process for synthesizing hybrid zinc aluminate using sodium tetrachloroaluminate from solid waste according to claim 1, characterized in that, In step S3, the method for detecting phosphorus content is to filter the reaction solution after the reaction is completed by heat preservation and stirring, and determine the phosphorus content of the filtrate. If the total phosphorus content in the filtrate is ≤8ppm, it is qualified and the next step can be performed; if the total phosphorus content in the filtrate is >8ppm, it is unqualified, and the filtrate continues to be reacted by heat preservation and stirring in step S3 until it is qualified.

7. The preparation process for synthesizing hybrid zinc aluminate using sodium tetrachloroaluminate from solid waste according to claim 1, characterized in that, The sodium hydroxide solution mentioned in step S4 is a 32% sodium hydroxide aqueous solution; the pH is controlled at 7-9.

8. The preparation process for synthesizing hybrid zinc aluminate using sodium tetrachloroaluminate from solid waste according to claim 7, characterized in that, In step S4, the pH is controlled to be 7.5~8.

5.

9. The preparation process for synthesizing hybrid zinc aluminate using sodium tetrachloroaluminate from solid waste according to claim 1, characterized in that, In step S5, the generated white zinc aluminate precursor precipitate is transferred to a high-pressure reactor for hydrothermal reaction. The temperature is raised to 130°C and the reaction is maintained for 1.5-2 hours.

10. The preparation process for synthesizing hybrid zinc aluminate using sodium tetrachloroaluminate from solid waste according to claim 1, characterized in that, In step S6, the pressure of negative pressure filtration is 0.08~0.09 MPa, the mass ratio of filter solid to deionized water is 1:2, and the filter solid is spray dried at a temperature of 100~110℃. Stop washing when the sodium chloride content in the filter solids is ≤0.05%.

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