Treatment method for recycling zirconium n-sulfate mother liquor

Abstract

The invention relates to the technical field, and provides a zirconium orthosulfate mother liquor recycling treatment method, which comprises: adding a zirconium orthosulfate mother liquor into a ZOC zirconium solution, and stirring to obtain a mixed solution; adding anhydrous sodium sulphate into the mixed solution, stirring and dissolving to obtain a blended solution; carrying out heating and heat preservation treatment on the blended solution to obtain a semi-finished product basic zirconium sulfate; and washing the semi-finished product basic zirconium sulfate, and then carrying out centrifugal treatment to obtain the finished product basic zirconium sulfate. According to the treatment method for recycling the zirconium orthosulfate mother liquor, efficient recycling and resource utilization of the zirconium orthosulfate mother liquor are achieved, the obtained finished product basic zirconium sulfate meets the product standard, economic benefits and environmental friendliness are achieved, and the treatment method is suitable for large-scale industrial production.

Description

Technical Field

[0001] The present application belongs to the technical field of chemical product resource utilization, and in particular relates to a treatment method for recycling and reusing zirconium orthosulfate mother liquor. Background Art

[0002] The traditional one-step zirconium sulfate production process offers advantages such as ease of operation, low cost, and consistent product quality. However, this process generates a significant amount of wastewater (i.e., zirconium orthosulfate mother liquor), which has become a bottleneck hindering the green development of the industry. ZrS mother liquor is highly acidic and contains Zr and Cl elements. Direct discharge requires significant ion-exchange membrane solution and alkali neutralization (2-2.5 tons of ion-exchange membrane solution per ton of zirconium orthosulfate mother liquor). This not only results in high wastewater treatment costs (approximately 2,000 yuan per ton) but also poses safety and environmental risks.

[0003] In the existing technology, some recycling processes are difficult to achieve due to the high acidity of zirconium sulfate mother liquor and impurities (such as Cl - ) interference, which can easily lead to uncontrolled pH in the reaction system. The resulting zirconium basic sulfate (ZBS) particles have poor crystal form, low purity, and insufficient yield, making it difficult to meet the quality requirements of industrial production. Therefore, developing a process that can efficiently recover zirconium resources from the mother liquor, reduce waste treatment costs, and fully reuse the mother liquor has become a pressing technical challenge in the zirconium orthosulfate production industry. Summary of the Invention

[0004] The purpose of this application is to provide a treatment method for recycling and reusing zirconium sulfate mother liquor, which can improve the problem that the basic zirconium sulfate particles generated by the recycling process have poor crystal form, low purity, insufficient yield, and are difficult to meet the product quality requirements of industrial production.

[0005] To achieve the above application objectives, the technical solutions adopted in this application are as follows: The present application provides a method for recycling and reusing zirconium orthosulfate mother liquor, the method comprising: Adding zirconium orthosulfate mother liquor to ZOC zirconium liquor and stirring to obtain a mixed solution; Adding sodium sulphite to the mixed solution and stirring to dissolve to obtain a blended solution; The blended solution is subjected to a heating and heat preservation treatment to obtain a semi-finished product of basic zirconium sulfate; The semi-finished basic zirconium sulfate is washed and then centrifuged to obtain a finished basic zirconium sulfate.

[0006] The present application provides a treatment method for recycling and reusing zirconium orthosulfate mother liquor, which comprises adding zirconium orthosulfate mother liquor to ZOC zirconium liquor and stirring to obtain a mixed solution, i.e., using zirconium orthosulfate mother liquor to replace part of sulfuric acid as a reaction raw material, thereby reducing the consumption of concentrated sulfuric acid and the risk of using hazardous chemicals; adding sodium sulfate to the mixed solution and stirring to dissolve it to obtain a blending solution, i.e., adjusting the pH of the reaction system by replacing part of the mother liquor with sodium sulfate, thereby solving the problems of low product quality and yield caused by direct reaction of the zirconium orthosulfate mother liquor with excessively high acidity and impurities; heating and insulating the blending solution, thereby promoting sufficient crystal growth, stabilizing the product particle size, uniforming the crystal form, and significantly improving the yield; after obtaining the semi-finished basic zirconium sulfate, the semi-finished basic zirconium sulfate is washed and then centrifuged, i.e., obtaining a stable finished product through solid-liquid separation, thereby realizing efficient reuse and resource utilization of the zirconium orthosulfate mother liquor; the obtained finished basic zirconium sulfate meets product standards, has both economic benefits and environmental protection, and is suitable for large-scale industrial production.

[0007] In some embodiments, the zirconium orthosulfate mother liquor has an acidity of 11-20N, a Zr content of 0-20 g / L, and a Cl content of ≤15%.

[0008] In some embodiments, the concentration of ZrO2 in the ZOC zirconium solution is 6-10%, the volume ratio of the zirconium orthosulfate mother solution to the ZOC zirconium solution is 3-4:40-50, and the acidity of the mixed solution is 1.3-2.0N.

[0009] In some embodiments, in the mixed solution obtained after stirring, the stirring speed is 100-200 r / min, and the stirring time is 15-30 min.

[0010] In some embodiments, the sulfur-to-zirconium ratio in the blended solution is 0.5-0.7 mol.

[0011] In some embodiments, the step of adding sodium sulfate to the mixed solution and stirring to dissolve the mixed solution to obtain a blended solution comprises: Add 1 / 3 of the sodium sulphate to the mixed solution and stir to dissolve; after 5 to 10 minutes, add another 1 / 3 of the sodium sulphate to the mixed solution and stir to dissolve; after another 5 to 10 minutes, add the remaining 1 / 3 of the sodium sulphate to the mixed solution and stir to dissolve to obtain a blended solution.

[0012] In some embodiments, in the heating and holding treatment of the blended solution to obtain the semi-finished basic zirconium sulfate, the heating rate is 1-3°C / min, the final control temperature of the heating is 90-97°C, and the holding time is 30-60min.

[0013] In some embodiments, in the washing treatment of the semi-finished basic zirconium sulfate, the washing liquid is at least one of deionized water and distilled water, and the mass ratio of the washing liquid to the semi-finished basic zirconium sulfate is 5:1.

[0014] In some embodiments, the centrifugal speed during the centrifugal treatment is 2000-3000 r / min, and the centrifugal time is 10-20 min.

[0015] In some embodiments, the impurity ion content in the ZOC zirconium solution satisfies: Fe 3+ <0.1g / L, Al 3+ <0.05g / L.

[0016] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 This is a flow chart of a treatment method for recycling and reusing zirconium orthosulfate mother liquor provided in an embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0020] In this application, the term "and / or" describes the relationship between associated objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0021] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or plural.

[0022] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0023] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0024] The weights of the relevant components mentioned in the examples of this application may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally increased or decreased according to the examples of this application, it is within the scope disclosed in the examples of this application. Specifically, the masses described in the examples of this application may be mass units known in the chemical industry, such as μg, mg, g, and kg.

[0025] The terms "first" and "second" are used solely for descriptive purposes, to distinguish objects, such as substances, from one another. They should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features being referred to. For example, without departing from the scope of the embodiments of this application, a first XX could also be referred to as a second XX, and similarly, a second XX could also be referred to as a first XX. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of such features.

[0026] In the traditional one-step zirconium sulfate production process, the preparation of zirconium orthosulfate (ZST) has the advantages of simple operation, low cost and stable product quality. However, this process produces a large amount of waste liquid (i.e., zirconium orthosulfate mother liquor), which has become a bottleneck restricting the green development of the industry. The mother liquor has the following characteristics: High acidity and complex composition: The acidity of zirconium sulfate mother liquor is relatively high, and it contains Zr and Cl elements. Direct discharge requires a large amount of ion membrane liquid alkali neutralization (2 to 2.5 tons of ion membrane liquid / ton of zirconium sulfate mother liquor), which not only leads to high wastewater treatment costs (about 2,000 yuan / ton), but also poses safety and environmental risks.

[0027] Recycling technology bottleneck: Some recycling processes are due to excessive acidity of the mother liquor, impurities (such as Cl - ) interference, which can easily lead to the loss of control of the pH of the reaction system. The resulting basic zirconium sulfate (ZBS) particles have poor crystal form, low purity, and insufficient yield, making it difficult to meet the product quality requirements of industrial production.

[0028] Waste of resources and environmental pressure: The zirconium element in the mother liquor cannot be effectively recovered, resulting in waste of resources. Its high pollution characteristics are contrary to the current environmental protection goals of "zero emissions" and "resource utilization" in the chemical industry.

[0029] Therefore, developing a process that can efficiently recover zirconium resources in the mother liquor, reduce the cost of three wastes treatment, and realize the full reuse of the mother liquor has become a technical problem that needs to be solved in the field of zirconium orthosulfate production. The existing technology lacks a mature solution that can accurately control the acidity of the mother liquor and the sulfur-zirconium ratio and replace sulfuric acid with sodium sulfate to adjust the reaction system. The present invention aims to break through the above technical bottlenecks by optimizing process parameters and replacing raw materials. Based on this, in order to improve the problem that the basic zirconium sulfate particles generated by the recycling process in the related art have poor crystal form, low purity, insufficient yield, and are difficult to meet the product quality requirements of industrial production, the embodiments of this application provide the following solution.

[0030] like Figure 1 As shown, the embodiment of the present application provides a method for recycling and reusing zirconium orthosulfate mother liquor, the method comprising: S100, adding zirconium orthosulfate mother liquor to ZOC zirconium liquor, and stirring to obtain a mixed solution.

[0031] S200, adding sodium sulfate to the mixed solution and stirring to dissolve to obtain a blended solution.

[0032] S300, heating and maintaining the blended solution to obtain a semi-finished product of basic zirconium sulfate.

[0033] S400, washing the semi-finished basic zirconium sulfate and then centrifuging it to obtain a finished basic zirconium sulfate.

[0034] As you can understand, ZOC zirconium solution refers to zirconium oxychloride solution. Sodium sulfate refers to sodium sulfate, which is used to adjust the sulfur-to-zirconium ratio in the blended solution. Although zirconium orthosulfate mother liquor contains a small amount of sulfate, its high acidity and unbalanced sulfur-to-zirconium ratio require exogenous sulfate supplementation to promote the formation of basic zirconium sulfate.

[0035] From the above, it can be seen that the processing method for recycling and reusing the zirconium orthosulfate mother liquor provided in the embodiment of the present application is as follows: the zirconium orthosulfate mother liquor is added to the ZOC zirconium liquid and stirred to obtain a mixed solution, that is, the zirconium orthosulfate mother liquor is used to replace part of the sulfuric acid as the reaction raw material, thereby reducing the consumption of concentrated sulfuric acid and the risk of using hazardous chemicals; the sodium sulfate is added to the mixed solution and stirred to dissolve to obtain a blending solution, that is, the pH of the reaction system is adjusted by replacing part of the mother liquor with sodium sulfate, thereby solving the problem of low product quality and yield caused by the direct reaction of the zirconium orthosulfate mother liquor with excessive acidity and impurities; the blending solution is heated and kept warm, which can promote the full growth of crystals, stable product particle size, uniform crystal form, and significantly improved yield. After obtaining the semi-finished basic zirconium sulfate, the semi-finished basic zirconium sulfate is washed and then centrifuged, that is, a stable finished product is obtained by solid-liquid separation, thereby realizing efficient reuse and resource utilization of the zirconium orthosulfate mother liquor. The obtained finished basic zirconium sulfate meets the product standards, has both economic benefits and environmental protection, and is suitable for large-scale industrial production.

[0036] In some embodiments, the acidity of the zirconium orthosulfate mother liquor is 11-20N, the Zr content is 0-20 g / L, and the Cl content is ≤15%.

[0037] It is understood that zirconium orthosulfate mother liquor, as a waste liquid from the one-step zirconium sulfate production process, uses concentrated sulfuric acid to dissolve zirconium ore, resulting in a high acid concentration in the zirconium orthosulfate mother liquor. The acidity of the zirconium orthosulfate mother liquor is 11-20N, and the Zr content is 0-20g / L, which is a normal production process. The acidity of the zirconium orthosulfate mother liquor is 11-20N, and can be, for example, 11N, 15N, 20N, etc., but is not limited to these. The Zr content is 0-20g / L, and can be, for example, 0g / L, 10g / L, 20g / L, etc., but is not limited to these. Cl may originate from impurities in the raw zirconium ore or process additives. Excessive Cl content can result in residual Cl in the finished basic zirconium sulfate, affecting its application in high-end applications such as catalysts and ceramics. A Cl content of ≤15% reduces interference from complexation reactions with crystallization, ensuring the crystal form and purity of the basic zirconium sulfate.

[0038] In some embodiments, the concentration of ZrO2 in the ZOC zirconium solution is 6-10%, the volume ratio of zirconium orthosulfate mother solution to ZOC zirconium solution is 3-4:40-50, and the acidity of the mixed solution is 1.3-2.0N.

[0039] It can be understood that the ZrO2 concentration in the ZOC zirconium solution is the stoichiometric standard of the Zr element, and the actual content of Zr ions in the solution can be converted through stoichiometry. The concentration of ZrO2 is 6~10%, for example, it can be 6%, 8%, 10%, etc., but not limited to this. For example, 9% zirconium solution (i.e., ZrO2 concentration is 9%), corresponding to a Zr ion concentration of about 0.3~0.4 mol / L. The volume ratio of zirconium orthosulfate mother liquor to ZOC zirconium liquid is 3~4:40~50, for example, it can be 3:40, 3:45, 3:50, 3.5:40, 3.5:45, 3.5:50, 4:40, 4:45, 4:50, etc., but not limited to this. The acidity of the mixed solution directly affects the existence form of Zr ions (such as ZrO 2+ If the acidity is too high, the sulfate ion and the Zr ion will not combine sufficiently, and the yield will be reduced; if the acidity is too low, zirconium hydroxide or basic zirconium chloride impurities may be generated, resulting in a decrease in the purity of the finished product (such as Cl - The acidity is 1.3-2.0N, for example, 1.3N, 1.6N, 2.0N, etc., but not limited thereto.

[0040] With this setup, a ZrO2 concentration of 6-10% ensures a stable total zirconium content in the mixed system while minimizing the risk of high solution viscosity and uneven stirring caused by excessive concentration. The volume ratio of mother liquor to ZOC zirconium solution is controlled at 3-4:40-50, and the mother liquor acidity is reduced from 11-20N to 1.3-2.0N through proportional dilution, creating the optimal acidity conditions for the formation of basic zirconium sulfate. (An acidic environment inhibits the formation of zirconium hydroxide and promotes the combination of sulfate and zirconium ions to form a basic salt.) Precisely controlling the zirconium concentration, dilution ratio, and acidity lays the foundation for subsequent adjustment of the sulfur-zirconium ratio using sodium sulfate, ensuring uniform growth of basic zirconium sulfate crystals. This also allows for resourceful utilization of the mother liquor's high acidity and reduces the consumption of concentrated sulfuric acid.

[0041] In some embodiments, in step S100, the mixed solution is obtained after stirring, and the stirring speed is 100-200 r / min, and the stirring time is 15-30 min.

[0042] It can be understood that the acidity of the zirconium sulfate mother liquor is 11~20N, and the ZOC zirconium liquid is a low-acidity zirconium oxychloride solution. The density and ion concentration of the two are quite different, and stirring is required to overcome the interfacial resistance and promote molecular-level mixing. At the same time, if the mixing is insufficient, it may lead to insufficient dilution of the mother liquor and excessive local acidity, thereby inhibiting the crystallization of basic zirconium sulfate and even generating soluble zirconium sulfate, reducing the yield. The stirring speed is 100~200r / min, for example, it can be 100r / min, 150r / min, 200r / min, etc., but is not limited to this. The stirring time is 15~30min, for example, it can be 15min, 20min, 30min, etc., but is not limited to this.

[0043] With this setting, a stirring speed of 100~200r / min can generate sufficient turbulence to reduce the phenomenon of "acid clusters" formed by the mother liquor in the zirconium liquid, thereby reducing local excessive acidity; a stirring time of 15~30min allows the zirconium ions and sulfate ions to be evenly distributed, providing a stable reaction system for the subsequent adjustment of the sulfur-zirconium ratio with alumina.

[0044] In some embodiments, the sulfur to zirconium ratio in the blended solution is 0.5 to 0.7 mol.

[0045] It can be understood that the sulfur-zirconium ratio (the molar ratio of sulfate to zirconium ions) is the core parameter that determines the composition of basic zirconium sulfate. Zr ions are mainly present in the form of ZrO under acidic conditions. 2+ Exists in the form of SO4 2- Combined to form [ZrO (SO4)] n- Complex ions then condense to form layered crystals. A sulfur-zirconium ratio of 0.5-0.7 mol corresponds to 0.5-0.7 sulfate groups binding to each zirconium ion. If the sulfur-zirconium ratio is lower than 0.5 mol, there is insufficient sulfate, and the zirconium ions hydrolyze to form zirconium hydroxide (Zr(OH)4)4 precipitate. If it is higher than 0.7 mol, there is an excess of sulfate, which easily forms zirconium orthosulfate (Zr(SO4)2), resulting in increased impurity content in the product.

[0046] In this way, by controlling the sulfur-zirconium ratio in the blending solution to 0.5~0.7 mol, the complex ions formed can be uniformly nucleated, promoting the growth of crystals along the (001) crystal plane, and ultimately obtaining uniform particles with qualified particle size, meeting the stringent requirements of high-end products (such as ceramic glazes) for particle dispersion. In addition, the sulfur-zirconium ratio forms a synergistic effect with the acidity of the mixed solution (1.3~2.0N): the acidic environment stabilizes ZrO 2+ Ionic form, combined with precise sulfate concentration, can reduce Cl - 、Fe 3+ The competitive coordination of impurity ions such as sulphate and chlorinated polyols can reduce the impurities in the finished product, while achieving efficient utilization of sulfate in the mother liquor, reducing the consumption of sodium sulphate by about 15% to 20%, and reducing production costs.

[0047] In some embodiments, in step S200, adding sodium sulfate to the mixed solution and stirring to dissolve to obtain a blended solution comprises: Add 1 / 3 of the sodium sulphate to the mixed solution and stir to dissolve; after 5 to 10 minutes, add another 1 / 3 of the sodium sulphate to the mixed solution and stir to dissolve; after another 5 to 10 minutes, add the remaining 1 / 3 of the sodium sulphate to the mixed solution and stir to dissolve to obtain a blended solution.

[0048] It is understandable that the zirconium sulfate mother liquor contains Cl - If sodium sulfate is added together, then SO4 2-The concentration suddenly increased, possibly due to Cl - Competitive coordination of ZrO 2+ , forming [ZrO (SO4)(Cl)] n- Complex complex ions such as SO4 interfere with ZBS crystallization, and high concentrations of SO4 2- It will trigger rapid nucleation and form a large number of small crystal nuclei, which will limit the space for crystal growth, wide particle size distribution of the final product, and even form amorphous precipitation. 2- Preferentially occupying coordination sites, reducing Cl - 5-10 min can be, for example, 5 min, 8 min, 10 min, etc., but is not limited thereto.

[0049] In this way, the addition of sodium sulfate in batches can dynamically control the sulfate concentration, balance the reaction rate and crystal growth kinetics, and avoid the generation of by-products, impurity inclusion and safety risks. At the same time, by controlling the interval time to 5~10min, it can provide sulfate ions (SO4 2- ) and Zr ions (ZrO 2+ ) complexation reaction to provide sufficient time to ensure that the [ZrO(SO4)] generated in each stage n- Complex ions are evenly distributed, reducing SO4 2- Sudden overdosage can lead to disordered nucleation. Furthermore, batch addition can disperse the total heat release over multiple stages, keeping system temperature fluctuations within ±2°C and reducing the hydrolysis of zirconium ions or the formation of crystal surface defects caused by sudden temperature rises. By adding sodium sulfate in three separate additions, each with a 5-10 minute interval, precise control of sulfate concentration can be achieved in a dynamic equilibrium, simultaneously optimizing the complexation reaction, crystal growth, and impurity control, ultimately yielding high-purity, uniformly sized basic zirconium sulfate while improving process safety and stability.

[0050] In some embodiments, in step S300, the blended solution is subjected to a heating and insulation treatment to obtain a semi-finished basic zirconium sulfate, with a heating rate of 1-3°C / min, a final control temperature of 90-97°C, and a insulation time of 30-60 min.

[0051] It is understood that the heating rate is 1-3°C / min, for example, 1°C / min, 2°C / min, 3°C / min, etc., but is not limited thereto. The final temperature control temperature of 90-97°C means that the temperature is finally raised to 90-97°C, for example, 90°C, 94°C, 97°C, etc., but is not limited thereto. The holding time is 30-60 minutes, for example, 30 minutes, 50 minutes, 60 minutes, etc., but is not limited thereto.

[0052] With this setup, a slow temperature increase (1-3°C / min) ensures uniform heat transfer within the system, maintaining the complex ion hydrolysis-condensation equilibrium and promoting orderly crystal growth along specific planes (such as the {110} plane), resulting in uniformly sized basic zirconium sulfate. The formation of basic zirconium sulfate proceeds through a complexation-condensation-crystallization process. A temperature of 90-97°C significantly accelerates the condensation reaction rate (reducing the activation energy by approximately 15 kJ / mol), allowing for the full formation of Zr-O-S bonds and ultimately yielding stable layered crystals. A holding time of 30-60 minutes allows for stress release within the crystals, reducing the risk of breakage.

[0053] In some embodiments, in step S400, the semi-finished basic zirconium sulfate is washed, and the washing liquid is at least one of deionized water and distilled water, and the mass ratio of the washing liquid to the semi-finished basic zirconium sulfate is 5:1.

[0054] It is understandable that the surface of the semi-finished basic zirconium sulfate adsorbs the residual sulfate (SO4 2- ), chloride ion (Cl - ), sodium ion (Na + ) and other impurity ions. The ionic impurities adsorbed on the surface of the semi-finished basic zirconium sulfate can be effectively dissolved by washing, and the impurity migration can be achieved through the diffusion effect at the solid-liquid interface.

[0055] With this arrangement, impurities on the surface of the semi-finished product, basic zirconium sulfate, can be effectively reduced by washing with the washing liquid. At the same time, the mass ratio of the washing liquid to the semi-finished product, basic zirconium sulfate, is controlled to be 5:1, so that the washing liquid can reach ion exchange equilibrium in a short time, reducing the concentration of residual impurities to below the detection limit.

[0056] In some embodiments, the centrifugal speed during the centrifugal treatment is 2000-3000 r / min, and the centrifugal time is 10-20 min.

[0057] It is understood that the centrifugal speed is 2000-3000 r / min, for example, 2000 r / min, 1500 r / min, 3000 r / min, etc., but not limited thereto. The centrifugal time is 10-20 minutes, for example, 10 minutes, 15 minutes, 20 minutes, etc., but not limited thereto. Centrifugation is key to efficient solid-liquid separation. When the speed is too low, the centrifugal force is insufficient, making it difficult to quickly overcome the viscous resistance between the washing liquid and the crystals, resulting in incomplete separation and an increased crystal moisture content (>15%). While a speed that is too high (e.g., >3000 r / min) can improve separation efficiency, it may also produce mechanical shear forces on the crystals.

[0058] This configuration, with a centrifugation speed of 2000-3000 r / min and a centrifugation time of 10-20 minutes, can reduce the crystal moisture content to ≤10% (the measured value in the example is 8-10%) while also preventing crystal breakage due to excessive stress. By controlling the centrifugation speed to 2000-3000 r / min and the centrifugation time to 10-20 minutes, the multiple goals of efficient solid-liquid separation, crystal structure preservation, and energy optimization are achieved, meeting the finished product moisture content and purity requirements while also being suitable for industrial continuous production.

[0059] In some embodiments, the impurity ion content in the ZOC zirconium solution satisfies: Fe 3+ <0.1g / L, Al 3+ <0.05g / L.

[0060] It is understandable that Fe in ZOC zirconium liquid 3+ 、Al 3+ Impurity ions such as zirconium ore raw materials (such as hematite and aluminum silicate associated with zircon sand) or corrosion of production equipment (such as Fe ions dissolved from stainless steel in acidic environment) 3+ ). If Fe 3+ If the content is too high, the Fe(OH)3 colloid produced by hydrolysis will be easily adsorbed on the surface of the basic zirconium sulfate crystal, forming an "impurity coating layer", which will hinder the crystal growth, widen the particle size distribution, and even cause agglomeration. 3+ It is a color-forming ion, and its content is directly related to the color of the finished product. 3+ If the content is too high, the Al(OH)3 colloid generated by hydrolysis may form a solid solution with Zr ions (such as Zr-Al-OS composite phase), change the unit cell parameters of basic zirconium sulfate, cause the XRD diffraction peak to shift, and affect the distribution of active sites of the product in the catalytic field.

[0061] By setting this up, Fe 3+ <0.1g / L, Al 3+ A concentration of <0.05g / L can increase the complexation reaction rate by 15%-20%, shorten the crystallization induction period to less than 30 minutes, and improve yield. This also eliminates impurity interference at the source, ensuring that basic zirconium sulfate crystals grow in a clean reaction environment. Ultimately, the finished product achieves high purity, low impurities, and stable physical properties (particle size, turbidity), meeting the quality requirements of high-end industrial zirconium chemicals.

[0062] The following describes the details in conjunction with specific embodiments.

[0063] Example 1 1) Take 100L zirconium sulfate mother liquor with acidity of 16N, Zr content of 2.8g / L and Cl content of 8%, and add it to 1400L of 9% ZrO2, Fe 3+ 0.08g / L, Al3+ The mixture was stirred in a 0.02 g / L ZOC zirconium solution at a stirring speed of 150 r / min for 20 min to obtain a mixed solution with an acidity of 1.6N.

[0064] 2) Prepare 24 kg of sodium sulphate, first add 8 kg of sodium sulphate to the mixed solution and stir to dissolve. After 7 minutes, add another 8 kg of sodium sulphate to the mixed solution and stir to dissolve. After another 7 minutes, add the remaining 8 kg of sodium sulphate to the mixed solution and stir to dissolve to obtain a blended solution with a sulfur-to-zirconium ratio of 0.54 mol.

[0065] 3) The blended solution was heated at a heating rate of 2°C / min to a final controlled temperature of 95°C, and then kept at this temperature for 40 minutes to obtain a semi-finished basic zirconium sulfate.

[0066] 4) The semi-finished basic zirconium sulfate was washed with 850 L of deionized water, and then placed in a centrifuge and centrifuged at a speed of 2500 r / min for 15 minutes to obtain the finished basic zirconium sulfate.

[0067] Example 2 1) Take 110L of zirconium sulfate mother liquor with acidity of 11N, Zr content of 0.2g / L and Cl content of 2%, and add it to 1500L of 6% ZrO2, Fe 3+ 0.02g / L, Al 3+ The mixture was stirred in a 0.01 g / L ZOC zirconium solution at a stirring speed of 100 r / min for 30 min to obtain a mixed solution with an acidity of 1.34N.

[0068] 2) Prepare 21 kg of sodium sulphate, first add 7 kg of sodium sulphate to the mixed solution and stir to dissolve. After 5 minutes, add another 7 kg of sodium sulphate to the mixed solution and stir to dissolve. After another 10 minutes, add the remaining 7 kg of sodium sulphate to the mixed solution and stir to dissolve to obtain a blended solution with a sulfur-to-zirconium ratio of 0.59 mol.

[0069] 3) The blended solution was heated at a heating rate of 1°C / min to a final controlled temperature of 90°C, and then kept at this temperature for 30 minutes to obtain a semi-finished basic zirconium sulfate.

[0070] 4) The semi-finished basic zirconium sulfate was washed with 650 L of deionized water, and then placed in a centrifuge and centrifuged at a speed of 2000 r / min for 20 minutes to obtain the finished basic zirconium sulfate.

[0071] Example 3 1) Take 130L of zirconium sulfate mother liquor with acidity of 20N, Zr content of 19.5g / L and Cl content of 14%, and add it to 1600L of 10% ZrO2, Fe 3+ 0.1g / L, Al 3+ The mixture was stirred in a 0.05 g / L ZOC zirconium solution at a stirring speed of 200 r / min for 30 min to obtain a mixed solution with an acidity of 1.95N.

[0072] 2) Prepare 36 kg of sodium sulphate, first add 12 kg of sodium sulphate to the mixed solution and stir to dissolve. After 10 minutes, add another 12 kg of sodium sulphate to the mixed solution and stir to dissolve. After another 10 minutes, add the remaining 12 kg of sodium sulphate to the mixed solution and stir to dissolve, to obtain a blended solution with a sulfur-to-zirconium ratio of 0.67 mol.

[0073] 3) The blended solution was heated at a heating rate of 3°C / min to a final controlled temperature of 97°C, and then kept at this temperature for 60 minutes to obtain a semi-finished basic zirconium sulfate.

[0074] 4) The semi-finished basic zirconium sulfate was washed with 1170 L of deionized water, and then placed in a centrifuge and centrifuged at a speed of 3000 r / min for 20 minutes to obtain the finished basic zirconium sulfate.

[0075] Comparative Example 1 1) Take 100L of zirconium sulfate mother liquor with acidity of 22N, Zr content of 2.8g / L and Cl content of 8%, and add it to 1400L of 9% ZrO2, Fe 3+ 0.1g / L, Al 3+ The mixture was stirred in a 0.05 g / L ZOC zirconium solution at a stirring speed of 200 r / min for 30 min to obtain a mixed solution with an acidity of 2.2N.

[0076] 2) The same process as steps 2), 3) and 4) of Example 1 was followed to obtain the finished product of basic zirconium sulfate.

[0077] Comparative Example 2 1) Take 130L of zirconium sulfate mother liquor with acidity of 20N, Zr content of 19.5g / L and Cl content of 14%, and add it to 1600L of 10% ZrO2, Fe 3+ 0.1g / L, Al 3+ The mixture was stirred in a 0.05 g / L ZOC zirconium solution at a stirring speed of 200 r / min for 30 min to obtain a mixed solution with an acidity of 1.95N.

[0078] 2) Add 18 kg of sodium sulfate to the mixed solution and stir to dissolve to obtain a blended solution with a sulfur-to-zirconium ratio of 0.34 mol.

[0079] 3) The blended solution was heated at a heating rate of 1°C / min to a final controlled temperature of 90°C, and then kept at this temperature for 30 minutes to obtain a semi-finished basic zirconium sulfate.

[0080] 4) The semi-finished basic zirconium sulfate was washed with 650 L of deionized water, and then placed in a centrifuge and centrifuged at a speed of 2000 r / min for 20 minutes to obtain the finished basic zirconium sulfate.

[0081] Comparative Example 3 1) Take 110L of zirconium sulfate mother liquor with acidity of 11N, Zr content of 0.2g / L and Cl content of 2%, and add it to 1500L of 6% ZrO2, Fe 3+ 0.02g / L, Al 3+ The mixture was stirred in a 0.01 g / L ZOC zirconium solution at a stirring speed of 100 r / min for 30 min to obtain a mixed solution with an acidity of 1.34N.

[0082] 2) Prepare 21 kg of sodium sulphate, first add 7 kg of sodium sulphate to the mixed solution and stir to dissolve. After 5 minutes, add another 7 kg of sodium sulphate to the mixed solution and stir to dissolve. After another 10 minutes, add the remaining 7 kg of sodium sulphate to the mixed solution and stir to dissolve to obtain a blended solution with a sulfur-to-zirconium ratio of 0.59 mol.

[0083] 3) The blended solution was heated at a heating rate of 1°C / min to a final controlled temperature of 90°C, and then kept at this temperature for 30 minutes to obtain a semi-finished basic zirconium sulfate.

[0084] 4) The semi-finished basic zirconium sulfate was washed with 510 L of deionized water, and then placed in a centrifuge and centrifuged at a speed of 2000 r / min for 20 minutes to obtain the finished basic zirconium sulfate.

[0085] The finished basic zirconium sulfate prepared in all the above examples and comparative examples was tested for zirconium content, impurity content (Fe2O3, Na2O, Cl), particle size (D50), and turbidity. The testing method is as follows: 1. Zirconium content: EDTA titration.

[0086] 2. Fe2O3: ICP-OES detection.

[0087] 3. Na2O: ICP-OES detection.

[0088] 4. Cl: ion chromatography.

[0089] 5. D50: Laser particle size analyzer.

[0090] 6. Turbidity: Add 20 ml of pure water and 10 ml of concentrated sulfuric acid, mix well, then add 40 g of finished basic zirconium sulfate, put into a 25°C constant temperature water bath, turn on magnetic stirring, and measure with a turbidimeter.

[0091] The test results are shown in Table 1 below.

[0092] The test data in Table 1 demonstrates that the presently disclosed method for recovering and reusing zirconium orthosulfate mother liquor achieves efficient reuse of the zirconium orthosulfate mother liquor, achieving both economical and environmentally friendly benefits and suitability for large-scale industrial production. The resulting basic zirconium sulfate exhibits minimal residual impurities, excellent particle dispersion, and meets the stringent solubility and clarity requirements of the catalyst and ceramic industries.

[0093] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for recycling zirconium orthosulfate mother liquor, characterized in that: The method comprises: Adding zirconium orthosulfate mother liquor to ZOC zirconium liquor and stirring to obtain a mixed solution; Adding sodium sulphite to the mixed solution and stirring to dissolve to obtain a blended solution; The blended solution is subjected to a heating and heat preservation treatment to obtain a semi-finished product of basic zirconium sulfate; The semi-finished product of basic zirconium sulfate is washed and then centrifuged to obtain finished product of basic zirconium sulfate.

2. The method for recycling zirconium orthosulfate mother liquor according to claim 1, wherein: The acidity of the zirconium orthosulfate mother liquor is 11-20N, the Zr content is 0-20g / L, and the Cl content is ≤15%.

3. The method for recycling zirconium orthosulfate mother liquor according to claim 1, wherein: The concentration of ZrO2 in the ZOC zirconium solution is 6-10%, the volume ratio of the zirconium orthosulfate mother solution to the ZOC zirconium solution is 3-4:40-50, and the acidity of the mixed solution is 1.3-2.0N.

4. The method for recycling zirconium orthosulfate mother liquor according to claim 1, wherein: In the mixed solution obtained after the stirring, the stirring speed is 100-200 r / min, and the stirring time is 15-30 min.

5. The method for recycling zirconium orthosulfate mother liquor according to claim 1, wherein: The sulfur-zirconium ratio in the blended solution is 0.5-0.7 mol.

6. The method for recycling zirconium orthosulfate mother liquor according to claim 1, wherein: The step of adding sodium sulphate to the mixed solution and stirring to dissolve the mixture to obtain a blended solution comprises: Add 1 / 3 of the sodium sulphate to the mixed solution and stir to dissolve; after 5 to 10 minutes, add another 1 / 3 of the sodium sulphate to the mixed solution and stir to dissolve; after another 5 to 10 minutes, add the remaining 1 / 3 of the sodium sulphate to the mixed solution and stir to dissolve to obtain a blended solution.

7. The method for recycling zirconium orthosulfate mother liquor according to claim 1, wherein: In the step of heating and holding the blended solution to obtain the semi-finished basic zirconium sulfate, the heating rate is 1-3°C / min, the final controlled temperature is 90-97°C, and the holding time is 30-60min.

8. The method for recycling zirconium orthosulfate mother liquor according to claim 1, wherein: In the washing treatment of the semi-finished product basic zirconium sulfate, the washing liquid is at least one of deionized water and distilled water, and the mass ratio of the washing liquid to the semi-finished product basic zirconium sulfate is 5:

1.

9. The method for recycling zirconium orthosulfate mother liquor according to claim 1, wherein: The centrifugal speed during the centrifugal treatment is 2000~3000r / min, and the centrifugal time is 10~20min.

10. The method for recycling zirconium orthosulfate mother liquor according to claim 1, wherein: The impurity ion content in the ZOC zirconium liquid satisfies: Fe 3+ <0.1g / L, Al 3+ <0.05g / L.

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