A defluorination process based on dynamic crystallization filtration technology

Abstract

The application relates to a defluorination process based on a dynamic crystallization filtration technology. The defluorination process combines mixed adsorption and dynamic crystallization filtration adsorption processes, and through overall design of a process flow, the defluorination process can realize defluorination treatment of materials under neutral or alkaline conditions, has good defluorination effect, high utilization efficiency of adsorbents, low material loss and low labor cost.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of lithium battery recycling, and particularly relates to a defluorination process based on a dynamic crystal filtration technology. BACKGROUND

[0002] The recycling of power batteries currently mainly focuses on the recycling of positive electrode materials, especially ternary material positive electrodes. Currently, the recycling mainly focuses on valuable metals such as lithium, cobalt, nickel and manganese. During the disassembly and regeneration of waste batteries, due to the presence of electrolyte, separator and fluorine-containing binder in waste lithium batteries, whether it is a pyrometallurgical process or a hydrometallurgical process, fluorine ions will inevitably be enriched, resulting in excessive fluorine content and quality degradation of downstream lithium products.

[0003] For this, patent document 1 mentions that when lithium batteries are recycled by a hydrometallurgical process, a series of problems will occur when the fluorine-containing liquid is treated in the later stage: 1) Since fluorine ions have strong corrosiveness to equipment, the longer the process and the more the treatment steps, the greater the damage to the equipment; 2) When the fluorine concentration is high, a part of the fluorine will enter the nickel-cobalt-manganese sulfate solution during extraction, thereby affecting the quality of the product; 3) The subsequent removal of heavy metals, oil and COD will be affected; 4) When the fluorine concentration is high, it will affect the purity of the recycled lithium.

[0004] Therefore, in the recycling of batteries, defluorination treatment is needed. Currently, there are three common defluorination processes in the industry:

[0005] (1) Precipitation method: commonly used for pretreatment of high-fluorine solutions, by adding lime, calcium salt, coagulant and other substances to form insoluble fluoride precipitate or co-precipitate, and then separating the solid and liquid to remove fluorine. However, this method can only reduce the fluorine concentration to 10-20 mg / L, and further deep treatment is needed. Moreover, this method can easily introduce excess calcium ions and other impurities, affecting the quality of the subsequent electrode material;

[0006] (2) Adsorption method: fluorine ions are stored on the adsorbent through ion exchange or other physicochemical reactions, thereby removing the fluorine ions. The adsorbent is then regenerated to restore its performance and recycled. Common adsorbents include activated alumina, modified zeolite, rare earth adsorbent and resin. This method can effectively reduce the fluorine content from about 50 mg / L to about 1 mg / L. However, this method is affected by pH and the efficiency of adsorbent regeneration, and the regeneration method and cost are factors that restrict its development;

[0007] Currently, the following two methods are commonly used for defluorination in the regeneration of lithium carbonate in the industrial field:

[0008] (1) After acid leaching, Ca 2+The agent (usually lime) precipitates CaF while adjusting the pH. The fluorine concentration is reduced to tens to 100 ppm by precipitation, and then further reduced to below 3 ppm by using a defluorination and calcium removal resin;

[0009] (2) For ternary batteries, after acid leaching and nickel-cobalt-manganese extraction, defluorination is achieved by using a mixed adsorption and precipitation process with a defluorination agent (usually aluminum-based or zirconium-based). F<3-5 ppm can be achieved by 2-stage reflux. The defluorination agent is repeatedly used through multiple regeneration processes.

[0010] Some defluorination processes in battery recycling have been reported. For example, patent document 1 discloses a method for removing fluorine from waste lithium batteries. The method involves adding an oxidizing agent and acid to waste lithium battery powder, performing oxidative acid leaching, then separating the solid and liquid to obtain a fluorine-containing purified liquid. Aluminum hydroxide is added to the fluorine-containing purified liquid to perform a precipitation reaction. The pH is adjusted by adding acid (4.0-5.5). Solid-liquid separation is performed to obtain a defluorinated liquid and sodium hexafluoroaluminate. Then, aluminum hydroxide is added to the liquid phase to perform a second precipitation reaction. After solid-liquid separation, the liquid phase is taken for extraction to obtain a nickel-cobalt-manganese sulfate solution, achieving the purpose of defluorination and recovery. The final fluorine concentration can be reduced to below 15 mg / L.

[0011] Patent document 2 discloses a method for removing fluorine from waste lithium batteries. The method involves mixing fluorine-containing battery powder with a fluorine-dissolving aid (sodium salt, etc.) solution to obtain defluorinated battery powder and a fluorine-containing washing liquid. A lithium precipitating agent is added to the fluorine-containing washing liquid to obtain a lithium-containing residue and a lithium-removed liquid. An excess of a defluorination agent (calcium salt or magnesium salt) is added to the lithium-removed liquid to obtain a fluorine-containing residue and a defluorinated liquid. This method can reduce the fluorine content of waste lithium ion batteries to below 0.11% before entering the recycling process.

[0012] Patent document 3 discloses a method for treating waste water from waste lithium battery electrolyte. Although it is not for the production process, its properties are the same. The method involves adding adsorbent powder and aluminum salt, adjusting the pH (7.0-8.5), and achieving flocculation and precipitation. The corresponding waste residue is then obtained by filtration. The waste residue is then heated and crushed at high temperature, and then soaked with water to desorb a lithium-containing solution. The waste liquid is treated by biodegradation and reverse osmosis to obtain standard clean water. The advantage of this method is that it can treat wastewater and recover lithium resources.

[0013] References:

[0014] Patent document 1: CN113943864A;

[0015] Patent document 2: CN110994062A;

[0016] Patent document 3: CN109467261A. SUMMARY

[0017] Problems to be Solved by the Invention

[0018] The fluorine content after the treatment of the method of patent document 1 is still about 15 mg / L, and it is impossible to achieve further reduction of the fluorine concentration by deep treatment, which directly affects the purity of the final lithium carbonate product and brings the risk of equipment corrosion in the concentration process. Moreover, the process is relatively complex, involving multiple pH adjustments and the addition of reagents, which undoubtedly increases the difficulty and also generates a large amount of sludge.

[0019] The fluorine content after the treatment of the method of patent document 2 is still very high and needs further deep treatment to achieve the purity requirements of the lithium carbonate product and control the risk of equipment corrosion. Moreover, a large amount of sludge is generated after precipitation, and some heavy metals are also lost.

[0020] The method of patent document 3 also increases the treatment cost due to the addition of a large amount of chemical reagents, generates a large amount of sludge, and may cause membrane fouling in the later stage. Moreover, the operation is relatively complex, the initial investment is large, and a large amount of sludge will also increase the entrainment amount, leading to an increase in lithium loss.

[0021] In summary, the existing fluorine removal methods have the following problems:

[0022] (a) The working range of the current fluorine removal agent and fluorine removal resin is mostly around pH 4, and the metal-based fluorine removal agent and fluorine removal resin will dissolve and fail below pH 3.5, thus leading to (i) a large requirement for acid-base adjustment of pH; (ii) a narrow working range, as there is a possibility of operation failure due to batch differences, and the possibility of excessive pH adjustment is large, which is easy to cause loss of the feed liquid.

[0023] (b) The fluorine removal agent and fluorine removal resin need to be regenerated, although the regeneration methods are different, but there are the following problems: (i) the fluorine removal agent regeneration consumes a large amount of acid and alkali; (ii) the fluorine removal agent regeneration design multiple solid-liquid separation processes, which may cause loss of precious metal liquid or dilution leading to decreased efficiency of lithium precipitation at the end; (iii) the resin adsorption has the phenomenon of aluminum or zirconium-based substances falling off after multiple uses; (iv) the regeneration of the fluorine removal agent and the fluorine removal resin will generate additional wastewater and waste residue, which has a high treatment cost.

[0024] Therefore, it is urgent to develop a fluorine removal method that can be carried out under neutral or alkaline conditions, has high fluorine removal efficiency, and does not generate or generates less wastewater and waste residue.

[0025] Solution to the Problem

[0026] In view of the above problems, the inventors have conducted long-term and in-depth research, and developed a defluorination process capable of being carried out under neutral or alkaline conditions by combining mixed adsorption with dynamic crystal filter adsorption process and through overall design of the process flow.

[0027] Specifically, the present application solves the problems of the present application by the following solutions.

[0028] [1] A defluorination process for reducing the fluorine content in a material to be defluorinated to obtain a defluorination-treated material, characterized in that it comprises a mixed adsorption unit and a dynamic crystal filter adsorption process, wherein

[0029] The mixed adsorption unit comprises a first-stage mixed adsorption process, wherein the first-stage mixed adsorption process comprises a mixed adsorption operation I and a solid-liquid separation operation I, in the mixed adsorption operation I, the mixed adsorption feed I is stirred; then in the solid-liquid separation operation I, the material after stirring is subjected to solid-liquid separation by using a solid-liquid separation device to obtain a filtrate I and solid waste;

[0030] The mixed adsorption feed I is the discharge material of the adsorbent backwashing operation of the dynamic crystal filter adsorption process;

[0031] The dynamic crystal filter adsorption process is carried out in a dynamic crystal filter device, the dynamic crystal filter device comprises one or more than two dynamic crystal filter elements, the dynamic crystal filter element comprises a tubular filter shell and one or more filter tubes located inside the filter shell, the tube wall of the filter tube is composed of a porous material; the inner wall of the filter shell and the outer wall of the filter tube have a gap for material flow;

[0032] The dynamic crystal filter adsorption process comprises an adsorbent coating operation, a dynamic crystal filter adsorption operation and an adsorbent backwashing operation in sequence;

[0033] In the adsorbent coating operation, the adsorbent is coated on the tube wall of the filter tube; in the dynamic crystal filter adsorption operation, the filtrate I is contacted with the adsorbent coated on the tube wall of the filter tube, thereby obtaining the defluorination-treated material; in the adsorbent backwashing operation, the adsorbent on the tube wall is backwashed by using a backwashing material S, and the obtained mixed material is sent to the first-stage mixed adsorption process as the discharge material of the adsorbent backwashing operation; the backwashing material S is the material to be defluorinated;

[0034] The adsorbent is granular;

[0035] The backwashing is an operation of contacting the backwashing material with the adsorbent, so that the adsorbent falls off from the tube wall of the filter tube of the dynamic crystal filter element or the solid-liquid separation device to obtain a mixed material comprising the backwashing material and the adsorbent.

[0036] [2] A defluorination process for reducing the fluorine content in a defluorination material to be treated to obtain a defluorination treated material, comprising a mixed adsorption unit and a dynamic crystal filtration adsorption process, wherein

[0037] The mixed adsorption unit comprises a first-stage mixed adsorption process and a second-stage mixed adsorption process, wherein the first-stage mixed adsorption process comprises a mixed adsorption operation I and a solid-liquid separation operation I, in which the mixed adsorption operation I is used to stir the mixed adsorption feed I; and then in the solid-liquid separation operation I, a solid-liquid separation device is used to separate the stirred material to obtain a filtrate I and solid waste;

[0038] The second-stage mixed adsorption process comprises, in sequence, a mixed adsorption operation II, a solid-liquid separation operation II and an adsorbent backwashing operation II; wherein the mixed adsorption operation II is used to stir the mixed adsorption feed II; and then in the solid-liquid separation operation II, a solid-liquid separation device is used to separate the stirred material to obtain a filtrate II; and then in the adsorbent backwashing operation II, a backwashing material II is used to backwash the adsorbent in the solid-liquid separation device to obtain a mixed material II containing the backwashing material and the adsorbent;

[0039] The mixed adsorption feed I is the mixed material II, the mixed adsorption feed II is the discharge material of the adsorbent backwashing operation of the dynamic crystal filtration adsorption process, and the backwashing material II is the defluorination material to be treated;

[0040] The dynamic crystal filtration adsorption process is carried out in a dynamic crystal filtration device, which comprises one or more than two dynamic crystal filtration elements, the dynamic crystal filtration element comprises a tubular filter shell and one or more filter tubes located inside the filter shell, the tube wall of the filter tube is composed of a porous material; the inner wall of the filter shell and the outer wall of the filter tube have a gap for the flow of material;

[0041] The dynamic crystal filtration adsorption process comprises, in sequence, an adsorbent coating operation, a dynamic crystal filtration adsorption operation and an adsorbent backwashing operation;

[0042] In the adsorbent coating operation, the adsorbent is coated on the tube wall of the filter tube; in the dynamic crystal filtration adsorption operation, the filtrate II is contacted with the adsorbent coated on the tube wall of the filter tube to obtain the defluorination treated material; and in the adsorbent backwashing operation, a backwashing material S is used to backwash the adsorbent on the tube wall to obtain a mixed material, which is sent to the second-stage mixed adsorption process as the discharge material of the adsorbent backwashing operation; the backwashing material S is the filtrate I;

[0043] The adsorbent is in the form of particles;

[0044] The backwashing is an operation of contacting a backwashing material with the adsorbent so as to make the adsorbent fall off from the filter tube wall of the solid-liquid separation device or the dynamic crystal filter element, thereby obtaining a mixed material comprising the backwashing material and the adsorbent.

[0045] [3] A defluorination process for reducing the fluorine content in a material to be defluorinated so as to obtain a defluorination-treated material, comprising a mixed adsorption unit and a dynamic crystal filter adsorption process, wherein

[0046] The mixed adsorption unit comprises a first-stage mixed adsorption process, a second-stage mixed adsorption process and a third-stage mixed adsorption process, wherein the first-stage mixed adsorption process comprises a mixed adsorption operation I and a solid-liquid separation operation I, in which the mixed adsorption operation I is performed on a mixed adsorption feed I; and then in the solid-liquid separation operation I, a solid-liquid separation device is used to separate the stirred material, thereby obtaining a filtrate I and a solid waste;

[0047] The second-stage mixed adsorption process comprises, in sequence, a mixed adsorption operation II, a solid-liquid separation operation II and an adsorbent backwashing operation II; wherein the mixed adsorption operation II is performed on a mixed adsorption feed II; and then in the solid-liquid separation operation II, a solid-liquid separation device is used to separate the stirred material, thereby obtaining a filtrate II; and then in the adsorbent backwashing operation II, a backwashing material II is used to backwash the adsorbent in the solid-liquid separation device, thereby obtaining a mixed material II comprising the backwashing material and the adsorbent;

[0048] The third-stage mixed adsorption process comprises, in sequence, a mixed adsorption operation III, a solid-liquid separation operation III and an adsorbent backwashing operation III; wherein the mixed adsorption operation III is performed on a mixed adsorption feed III; and then in the solid-liquid separation operation III, a solid-liquid separation device is used to separate the stirred material, thereby obtaining a filtrate III; and then in the adsorbent backwashing operation III, a backwashing material III is used to backwash the adsorbent in the solid-liquid separation device, thereby obtaining a mixed material III comprising the backwashing material and the adsorbent;

[0049] The mixed adsorption feed I is the mixed material II, the mixed adsorption feed II is the mixed material III, the mixed adsorption feed III is the discharge material of the adsorbent backwashing operation of the dynamic crystal filter adsorption process; the backwashing material II is the material to be defluorinated, and the backwashing material III is the filtrate I;

[0050] The dynamic crystallization filtration adsorption process is performed in a dynamic crystallization filtration device, the dynamic crystallization filtration device comprising one or more than two dynamic crystallization filtration elements, the dynamic crystallization filtration element comprising a tubular filter shell and one or more filter tubes located inside the filter shell, the tube wall of the filter tube being composed of a porous material; the inner wall of the filter shell and the outer wall of the filter tube have a gap for material flow;

[0051] The dynamic crystallization filtration adsorption process comprises in sequence an adsorbent coating operation, a dynamic crystallization filtration adsorption operation and an adsorbent backwashing operation;

[0052] In the adsorbent coating operation, the adsorbent is coated on the tube wall of the filter tube; in the dynamic crystallization filtration adsorption operation, the filtrate III is brought into contact with the adsorbent coated on the tube wall of the filter tube, thereby obtaining the defluorinated material; in the adsorbent backwashing operation, the adsorbent on the tube wall is backwashed by using the backwashing material S, and the obtained mixed material is sent to the third-stage mixed adsorption process as the discharge material of the adsorbent backwashing operation; the backwashing material S is the filtrate II;

[0053] The adsorbent is in a granular form;

[0054] The backwashing is an operation of bringing the backwashing material into contact with the adsorbent, thereby causing the adsorbent to fall off from the tube wall of the filter tube of the dynamic crystallization filtration element or the solid-liquid separation device, and thereby obtaining a mixed material comprising the backwashing material and the adsorbent.

[0055] [4] A defluorination process for reducing the fluorine content in a material to be defluorinated, thereby obtaining a defluorinated material, comprising a mixed adsorption unit and a dynamic crystallization filtration adsorption process, wherein

[0056] The mixed adsorption unit comprises a first-stage mixed adsorption process, a second-stage mixed adsorption process, a third-stage mixed adsorption process and a fourth-stage mixed adsorption process, wherein the first-stage mixed adsorption process comprises a mixed adsorption operation I and a solid-liquid separation operation I, in the mixed adsorption operation I, the mixed adsorption feed I is stirred; then in the solid-liquid separation operation I, the stirred material is subjected to solid-liquid separation by using a solid-liquid separation device, thereby obtaining a filtrate I and a solid waste;

[0057] The second-stage mixed adsorption process comprises in sequence a mixed adsorption operation II, a solid-liquid separation operation II and an adsorbent backwashing operation II; wherein in the mixed adsorption operation II, the mixed adsorption feed II is stirred; then in the solid-liquid separation operation II, the stirred material is subjected to solid-liquid separation by using a solid-liquid separation device, thereby obtaining a filtrate II; then in the adsorbent backwashing operation II, the adsorbent in the solid-liquid separation device is backwashed by using a backwashing material II, thereby obtaining a mixed material II comprising the backwashing material and the adsorbent;

[0058] The third-stage mixed adsorption process sequentially comprises a mixed adsorption operation III, a solid-liquid separation operation III and an adsorbent backwashing operation III; wherein, in the mixed adsorption operation III, the mixed adsorption feed III is stirred; then in the solid-liquid separation operation III, the solid-liquid separation device is used to separate the stirred material to obtain the filtrate III; then in the adsorbent backwashing operation III, the adsorbent in the solid-liquid separation device is backwashed by the backwashing material III to obtain the mixed material III containing the backwashing material and the adsorbent;

[0059] The fourth-stage mixed adsorption process sequentially comprises a mixed adsorption operation IV, a solid-liquid separation operation IV and an adsorbent backwashing operation IV; wherein, in the mixed adsorption operation IV, the mixed adsorption feed IV is stirred; then in the solid-liquid separation operation IV, the solid-liquid separation device is used to separate the stirred material to obtain the filtrate IV; then in the adsorbent backwashing operation IV, the adsorbent in the solid-liquid separation device is backwashed by the backwashing material IV to obtain the mixed material IV containing the backwashing material and the adsorbent;

[0060] The mixed adsorption feed I is the mixed material II, the mixed adsorption feed II is the mixed material III, the mixed adsorption feed III is the mixed material IV, and the mixed adsorption feed IV is the discharge material of the adsorbent backwashing operation of the dynamic crystal filtration adsorption process; the backwashing material II is the fluoride removal material, the backwashing material III is the filtrate I, and the backwashing material IV is the filtrate II;

[0061] The dynamic crystal filtration adsorption process is carried out in a dynamic crystal filtration device, and the dynamic crystal filtration device comprises one or more than two dynamic crystal filtration elements, the dynamic crystal filtration element comprises a tubular filter shell and one or more filter tubes located inside the filter shell, and the tube wall of the filter tube is composed of a porous material; the inner wall of the filter shell and the outer wall of the filter tube have a gap for material flow;

[0062] The dynamic crystal filtration adsorption process sequentially comprises an adsorbent coating operation, a dynamic crystal filtration adsorption operation and an adsorbent backwashing operation;

[0063] In the adsorbent coating operation, the adsorbent is coated on the tube wall of the filter tube; in the dynamic crystal filtration adsorption operation, the filtrate IV is contacted with the adsorbent coated on the tube wall of the filter tube to obtain the fluoride removal treated material; in the adsorbent backwashing operation, the adsorbent on the tube wall is backwashed by the backwashing material S to obtain the mixed material, which is sent to the third-stage mixed adsorption process as the discharge material of the adsorbent backwashing operation; the backwashing material S is the filtrate III;

[0064] The adsorbent is in a granular form;

[0065] The backwashing is an operation of contacting a backwashing material with the adsorbent so as to make the adsorbent fall off from the filter tube wall of the solid-liquid separation device or the dynamic crystal filter element, thereby obtaining a mixed material comprising the backwashing material and the adsorbent.

[0066] [5] The defluorination process according to any one of [1] to [4], wherein the solid-liquid separation device in the first-stage mixed adsorption process is a plate-and-frame filter press or a centrifugal separator; and the solid-liquid separation device in the second-stage to fourth-stage mixed adsorption processes is a dynamic crystal filter element.

[0067] [6] The defluorination process according to any one of [1] to [4], wherein the adsorbent is one or more selected from oxides of aluminum, zirconium, titanium, magnesium, iron, lanthanum, or a composite oxide thereof; the particle size of the adsorbent is 0.1 to 50 μm, preferably 0.5 to 5 μm; and in the adsorbent coating operation, the coating amount of the adsorbent on the inner wall of the filter tube is 20 to 2400 g / m2, preferably 100 to 400 g / m2.

[0068] [7] The defluorination process according to any one of [1] to [4], wherein the adsorbent coating operation is performed by delivering an adsorbent slurry to the inside of the filter tube and performing a cross-flow filtration operation so as to make the adsorbent adhere to the tube wall of the filter tube, the adsorbent slurry comprising the adsorbent and water.

[0069] [8] The defluorination process according to any one of [1] to [4], wherein the dynamic crystal filter device comprises one group or two or more groups of dynamic crystal filter element groups connected in series, wherein each group of dynamic crystal filter elements comprises one or two or more dynamic crystal filter elements connected in parallel; and in the dynamic crystal filter adsorption operation, the filtrate obtained by the solid-liquid separation operation of the last-stage mixed adsorption process is subjected to cross-flow filtration in all of the groups of dynamic crystal filter elements, or subjected to dead-end filtration in all of the groups of dynamic crystal filter elements, or subjected to cross-flow filtration in some of the groups of dynamic crystal filter elements and subjected to dead-end filtration in the other groups of dynamic crystal filter elements.

[0070] Preferably, the operating flux of the dynamic crystal filter element is 50 to 200 LMH; more preferably 50 to 150 LMH; and in the case of cross-flow filtration, the ratio of the cross-flow flow rate of the material liquid through the filter tube to the discharge flow rate of the material after the defluorination treatment is (1:2) to (1:10); more preferably (1:3) to (1:6).

[0071] [9] The defluorination process according to any one of [1] to [4], wherein the adsorbent backwashing operation in the dynamic crystal filter adsorption process is performed in the following manner:

[0072] It comprises three sections of (a) backflush, (b) upflush and (c) downflush in sequence; wherein (a) backflush is to flow the backwash material from the outside of the filter tube to the inside; (b) upflush is to flow the backwash material from the lower end of the filter tube into and from the upper end; (c) downflush is to flow the backwash material from the upper end of the filter tube into and from the lower end;

[0073] Preferably,

[0074] In the (a) backflush section, the flux of the backwash material ranges from 1000 to 10000 LMH; preferably from 3000 to 5000 LMH; and the duration is 3 to 60 s; preferably 5 to 10 s;

[0075] In the (b) upflush section, the flow rate of the backwash material is 10 to 400 cm / s; preferably 15 to 25 cm / s; and the duration is 5 to 30 s; preferably 5 to 10 s;

[0076] In the (c) downflush section, the flow rate of the backwash material is 10 to 400 cm / s; preferably 15 to 25 cm / s; and the duration is 5 to 30 s; preferably 5 to 10 s;

[0077] The three sections of (a) backflush, (b) upflush and (c) downflush can be repeated 1 to 5 times, preferably 1 to 3 times.

[0078]

[10] The defluorination process according to any one of [1] to [3], wherein the pH of the material to be defluorinated is 5 to 9, and in at least one solid-liquid separation operation, the pH of the filtrate is controlled to be 5 to 9.

[0079]

[11] The defluorination process according to any one of [1] to [3], wherein the discharged material of the process is only the material after defluorination treatment and the solid waste obtained in the solid-liquid separation operation I.

[0080] Effects of the application

[0081] The defluorination process of the application can realize defluorination treatment of the material under neutral or alkaline conditions, and has good defluorination effect, high utilization efficiency of adsorbent, less material loss and low labor cost.

[0082] The application fully improves the utilization efficiency and adsorption capacity of the adsorbent by reasonable design of the process flow, use of the dynamic crystal filter device and multiple reverse application.

[0083] The application uses the dynamic backwashing process characteristics of the dynamic crystal filter, uses the effluent of the previous section to backwash after adsorption equilibrium of the adsorbent and solid-liquid separation, and refluxes the adsorbent to the upstream process, so as to realize:

[0084] (1) The dynamic crystal filter automatic backwashing process is used to make the solid-liquid separation automatic, and greatly reduce the manual operation and labor cost in the traditional adsorbent reverse application process;

[0085] (2) The material is completely closed in the process, reducing the loss of high-value materials, and the only discharge is the solid waste after the solid-liquid separation of the adsorbent after adsorption saturation in the first-stage mixed adsorption process. BRIEF DESCRIPTION OF DRAWINGS

[0086] Figure 1 The process flow diagram of the preferred embodiment one of the present application is shown in the figure;

[0087] Figure 2 The process flow diagram of the preferred embodiment two of the present application is shown in the figure;

[0088] Figure 3 And Figure 4 The schematic diagram of the dynamic crystal filter device is shown in the figure. DETAILED DESCRIPTION

[0089] Various exemplary embodiments, features, and aspects of the present application will be described in detail below. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations.

[0090] In addition, in order to better illustrate the present application, numerous specific details are given in the following detailed description. Those skilled in the art will understand that the present application can be practiced without certain specific details. In some instances, well-known methods, means, instruments and steps have not been described in detail in order to highlight the principles of the present application.

[0091] Unless otherwise specified, the units used in the specification are international standard units, and the numerical values and numerical ranges appearing in the present application should be understood to include the systematic errors that are inevitable in industrial production.

[0092] In the specification, the "connection", "connection" or similar terms described for each component of the device or equipment means that the material can be transported from one component to another, including the case where the components are directly connected or not directly connected, and for the case where they are not directly connected, they can be connected through pipes or via other components.

[0093] In the specification, "in turn" for each component of the device or equipment means that the material can pass through the components in the order described.

[0094] In the present specification, "upstream" or "downstream" described with respect to the relative positions of the respective components of an apparatus or a device is described based on the direction of flow of a material when the apparatus or the device is operated.

[0095] In the present specification, "percentage" or "%" used herein means molar percentage or mol%.

[0096] In the present specification, a numerical range indicated using "above" or "below" means a numerical range including the number.

[0097] In the present specification, the meaning indicated using "may" includes both the meaning of performing a certain process and the meaning of not performing the certain process.

[0098] In the present specification, the phrase "some embodiments / pref erred embodiments", "other embodiments / pref erred embodiments", "embodiments", and the like means that the particular feature (e.g., characteristic, structure, property, and / or characteristic) described is included in at least one embodiment described herein, and can exist in some embodiments or can not exist in other embodiments. In addition, it should be understood that the described features can be combined in any suitable manner in various embodiments.

[0099] In the present specification, a numerical range indicated using "numerical value A to numerical value B" means a range including the end point values A and B.

[0100] In the present specification, when "ordinary temperature" or "room temperature" is used, the temperature can be 20 to 30°C.

[0101] An object of the present application is to provide a fluorine removal process which is a process for reducing the content of fluorine in a material to be subjected to fluorine removal to obtain a material subjected to fluorine removal, characterized by comprising a mixed adsorption unit and a dynamic crystallization filtration adsorption process, wherein

[0102] The mixed adsorption unit comprises one to four stages of mixed adsorption processes, i.e., comprises a first stage of mixed adsorption process and optionally comprises a second stage of mixed adsorption process, a third stage of mixed adsorption process, and a fourth stage of mixed adsorption process;

[0103] When the one stage of mixed adsorption process is included, i.e., only the first stage of mixed adsorption process is included, the mixed adsorption process comprises a mixed adsorption operation I and a solid-liquid separation operation I, in the mixed adsorption operation, the discharged material of the dynamic crystallization filtration adsorption process is stirred; then in the solid-liquid separation operation, the material after stirring is subjected to solid-liquid separation using a solid-liquid separation device to obtain a filtrate I and a solid waste;

[0104] When the two or more stages of mixed adsorption processes are included, the first stage of mixed adsorption process includes a mixed adsorption operation I and a solid-liquid separation operation I, in which the mixture II obtained by the backwashing operation in the second stage of mixed adsorption process is stirred in the mixed adsorption operation I; then in the solid-liquid separation operation I, the solid-liquid separation device is used to separate the stirred material to obtain the filtrate I and the solid waste;

[0105] The second to last stage of mixed adsorption process includes a mixed adsorption operation (II, III, IV), a solid-liquid separation operation (II, III, IV) and an adsorbent backwashing operation (II, III, IV) in turn; wherein, in the mixed adsorption operation (II, III, IV), the mixed adsorption feed (II, III, IV) is stirred; then in the solid-liquid separation operation (II, III, IV), the solid-liquid separation device is used to separate the stirred material to obtain the filtrate (II, III, IV); then in the adsorbent backwashing operation (II, III, IV), the backwashing material (II, III, IV) is used to flush the adsorbent in the solid-liquid separation device to obtain the mixture (II, III, IV) containing the backwashing material and the adsorbent;

[0106] When the two stages of mixed adsorption processes are included, the mixed adsorption feed II in the second stage of mixed adsorption process is the discharge material of the dynamic crystal filter backwashing process, and the backwashing material II is the fluoride removal material to be removed;

[0107] When the three stages of mixed adsorption processes are included, the mixed adsorption feed II in the second stage of mixed adsorption process is the mixture III obtained by the backwashing operation in the third stage of mixed adsorption process, and the backwashing material II is the fluoride removal material to be removed; the mixed adsorption feed III in the third stage of mixed adsorption process is the discharge material of the dynamic crystal filter backwashing process, and the backwashing material III is the filtrate I obtained by the solid-liquid separation in the first stage of mixed adsorption process;

[0108] When the four stages of mixed adsorption processes are included, the mixed adsorption feed II in the second stage of mixed adsorption process is the mixture III obtained by the backwashing operation in the third stage of mixed adsorption process, and the backwashing material is the fluoride removal material to be removed; the mixed adsorption feed III in the third stage of mixed adsorption process is the mixture IV obtained by the backwashing operation in the fourth stage of mixed adsorption process, and the backwashing material III is the filtrate I obtained by the solid-liquid separation in the first stage of mixed adsorption process; the mixed adsorption feed IV in the fourth stage of mixed adsorption process is the discharge material of the dynamic crystal filter backwashing process, and the backwashing material IV is the filtrate II obtained by the solid-liquid separation in the second stage of mixed adsorption process;

[0109] The dynamic crystallization filtration adsorption process is carried out in a dynamic crystallization filtration device, which comprises one or more than two dynamic crystallization filtration elements, each of which comprises a tubular filter shell and one or more filter tubes inside the filter shell, the tube wall of the filter tube being composed of a porous material; and a gap for material flow is formed between the inner wall of the filter shell and the outer wall of the filter tube.

[0110] The dynamic crystallization filtration adsorption process comprises, in sequence, an adsorbent coating operation, a dynamic crystallization filtration adsorption operation, and an adsorbent backwashing operation.

[0111] In the adsorbent coating operation, the adsorbent is coated on the tube wall of the filter tube; in the dynamic crystallization filtration adsorption operation, the filtrate obtained by the solid-liquid separation operation of the last stage of the mixed adsorption process is brought into contact with the adsorbent coated on the tube wall of the filter tube, thereby obtaining the fluoride-removed material; and in the adsorbent backwashing operation, the adsorbent on the tube wall is backwashed by using the backwashing material S, and the obtained mixed material is sent to the last stage of the mixed adsorption process as the discharge material of the dynamic crystallization filtration process, wherein when the mixed adsorption process comprises two or more stages, the backwashing material is the filtrate obtained by the solid-liquid separation operation of the penultimate stage of the mixed adsorption process, and when the mixed adsorption process comprises one stage, the backwashing material is the fluoride-removal material.

[0112] The adsorbent is in the form of particles.

[0113] The backwashing operation refers to an operation of bringing a liquid material into contact with the adsorbent, so that the adsorbent falls off from the tube wall of the filter tube of the dynamic crystallization filtration element or the solid-liquid separation device, thereby obtaining a mixed material comprising the liquid material and the adsorbent.

[0114] The process of the present application is described in detail below.

[0115] <fluoride-removal material>

[0116] In the present specification, the "fluoride-removal material" refers to a liquid material comprising fluorine elements in any form, which has not been treated by the fluoride-removal process of the present application.

[0117] In one embodiment, the fluoride-removal material comprises fluoride ions.

[0118] In one embodiment, the content of fluorine elements in the fluoride-removal material is 100 mg / L or more, for example, 200 mg / L or more, 300 mg / L or more, 400 mg / L or more, 500 mg / L or more, 600 mg / L or more, 700 mg / L or more, 800 mg / L or more, 900 mg / L or more, or 1000 mg / L or more.

[0119] In one embodiment, the content of fluorine element in the material to be defluorinated is 2000 mg / L or less, for example, 1900 mg / L or less, 1800 mg / L or less, 1700 mg / L or less, 1600 mg / L or less, 1500 mg / L or less, 1400 mg / L or less, 1300 mg / L or less, 1200 mg / L or less, 1100 mg / L or less.

[0120] In one embodiment, the material to be defluorinated is neutral or alkaline, and has a pH of 5 to 9, preferably 6.5 to 7.5.

[0121] <Material after defluorination>

[0122] In the present specification, the "material after defluorination" refers to the material obtained after the defluorination process of the present application. Specifically, the material after defluorination is the material discharged after the dynamic crystallization filtration and adsorption operation in the dynamic crystallization filtration and adsorption process.

[0123] In one embodiment, the content of fluorine element in the material after defluorination of the present application is 3 mg / L or less.

[0124] <Adsorbent>

[0125] In the present specification, the "adsorbent" is in the form of particles, which can adsorb fluorine element so as to reduce the content of fluorine in the material in contact therewith, and is insoluble in water.

[0126] In the present specification, the "adsorption" of fluorine element by the adsorbent refers to the combination of the adsorbent with fluorine element, and the combination mode includes but is not limited to physical adsorption and formation of chemical bonds.

[0127] In one embodiment, the adsorbent is one or more selected from oxides of aluminum, zirconium, titanium, magnesium, iron, lanthanum or their composite oxides.

[0128] In one embodiment, the particle size of the adsorbent is 0.1 to 50 μm, preferably 0.5 to 30 μm, more preferably 1 to 20 μm, and further preferably 2 to 10 μm.

[0129] In a preferred embodiment, the adsorbent comprises an aluminum-based modified composite oxide, which can be prepared, for example, by the following method described in patent document CN110732305A:

[0130] (1) configuring raw materials, the raw materials comprising inorganic alkali powder in powder form and aluminum salt powder in powder form, wherein the ratio of aluminum ions to hydroxyl groups is Al + : ～OH = 1 : 2.5~1 : 4; (2) generating amorphous aluminum hydroxide hydrate complex solution, including the following methods: mixing inorganic base solution prepared by inorganic base powder with aluminum salt solution prepared by aluminum salt powder; or adding inorganic base solution prepared by inorganic base powder and aluminum salt solution prepared by aluminum salt powder into a container at the same time; or adding inorganic base powder into aluminum salt solution prepared by aluminum salt powder; or mixing inorganic base powder and aluminum salt powder in proportion and then adding water; stirring the solution until the pH value of the solution reaches neutral or stirring the solution to keep the solution neutral, and generating amorphous aluminum hydroxide hydrate complex from inorganic base and aluminum salt; (3) heating to generate aluminum oxide, heating the amorphous aluminum hydroxide hydrate complex solution to 95~110℃, and the holding time is not less than 10 minutes, to generate strong aluminum hydroxyl oxide hydrate complex; (4) cooling, cooling the aluminum oxide after the holding is over, and then storing at room temperature.

[0131] The aluminum-based modified composite oxide is preferably prepared according to the preferred embodiments disclosed in patent document CN110732305A, for example, any one of embodiments 1 to 8 thereof.

[0132] <mixed adsorption unit>

[0133] The mixed adsorption unit includes 1, 2, 3 or 4 stages of mixed adsorption processes, by which the fluorine content in the fluorine-containing material is reduced by making the fluorine-containing material fully contact with the adsorbent.

[0134] In the present specification, the term “fluorine-containing material” refers to the material to be defluorinated and the material to be defluorinated after being processed by any process or operation of the present application. Those skilled in the art will understand that the composition or state of the fluorine-containing material may be different in different processes or operations, and the specific composition or state of the fluorine-containing material can be determined by the description of the context.

[0135] The first-stage mixed adsorption process includes, in sequence, a mixed adsorption operation and a solid-liquid separation operation, and the second-stage to fourth-stage mixed adsorption processes include, in sequence, a mixed adsorption operation, a solid-liquid separation operation and an adsorbent backwashing operation, if present.

[0136] In the mixed adsorption operation, each mixed adsorption feed including the fluorine-containing material (backwashing material) and the adsorbent is stirred, so that the fluorine-containing material fully contacts with the adsorbent, so that the fluorine in the fluorine-containing material is adsorbed by the adsorbent, as a result, the fluorine content in the fluorine-containing material is reduced, and the amount of fluorine adsorbed by the adsorbent is increased.

[0137] The mixed adsorption operation can be carried out at 10~90℃, preferably at 15~50℃, more preferably at 20~35℃. The stirring time can be 10~120min, preferably 30~90min.

[0138] In the solid-liquid separation operation, the solid-liquid separation device is used to separate the stirred material to obtain filtrate.

[0139] The solid-liquid separation device is not particularly limited in the present application, which can be a solid-liquid separation device known in the art, including but not limited to plate-and-frame filter press, centrifugal separator, dynamic crystal filter element, etc.

[0140] Preferably, the solid-liquid separation operation further comprises controlling the pH of the obtained filtrate to be 5-9.

[0141] In the adsorbent backwashing operation, the backwashing material is used to flush the adsorbent in the solid-liquid separation device, so that the adsorbent leaves the solid-liquid separation device together with the backwashing material to obtain a mixture containing the backwashing material and the adsorbent.

[0142] In preferred embodiments, the solid-liquid separation device in the first-stage mixed adsorption process is a plate-and-frame filter press or a centrifugal separator; and the solid-liquid separation device in the second-stage to fourth-stage mixed adsorption process (if present) is a dynamic crystal filter element.

[0143] In the second-stage to fourth-stage mixed adsorption process, in the solid-liquid separation operation, the stirred material is allowed to enter the filter tube of the dynamic crystal filter element for cross-flow or dead-end filtration, wherein the adsorbent is retained on the inner wall of the filter tube and the fluorine-containing material is filtered out of the filter tube to become filtrate.

[0144] Preferably, the dynamic crystal filter element as the solid-liquid separation device has a processing flux of 200-800 LMH, preferably 400-600 LMH; wherein the flow rate of cross-flow through the filter tube of the dynamic crystal filter element is in the ratio of (0.1:1) to (5:1), preferably (0.2:1) to (0.5:1) to the flow rate of permeation through the filter tube.

[0145] In specific embodiments, in the second-stage to fourth-stage mixed adsorption process, the adsorbent backwashing operation can be performed in the same manner as described below for the adsorbent backwashing operation in the dynamic crystal filter adsorption process.

[0146] <Dynamic crystal filter device>

[0147] The dynamic crystal filter device comprises one or more than two dynamic crystal filter elements, wherein each dynamic crystal filter element comprises a tubular filter housing and one or more filter tubes located inside the filter housing, the tube wall of the filter tube is composed of porous material; and the inner wall of the filter housing and the outer wall of the filter tube have a gap for material flow.

[0148] In one embodiment, the two ends of the filter shell are provided with plate-shaped positioning portions, the plane direction of the plate-shaped positioning portions is substantially parallel to the cross section of the filter shell. The positioning portions are provided with openings, which are in communication with the interior of the filter tube, for the material in the interior of the filter tube to enter and exit. The filter shell is also provided with openings, for the material in the gap between the inner wall of the filter shell and the outer wall of the filter tube to enter and exit.

[0149] In one embodiment, the porous material is a flexible material. The pore size of the porous material is preferably 0.01-10 μm. The pore size of the porous material is smaller than the particle size of the adsorbent, so that the adsorbent can be coated on the tube wall of the filter tube.

[0150] In a preferred embodiment, the dynamic crystallization filter device is a liquid treatment device described in patent document CN110304701A. Specifically, as shown in Figure 3 、 Figure 4 The liquid treatment device includes a filter body 100 and a filter tube 200; the filter body 100 is provided with a liquid flow cavity, the filter tube 200 is arranged in the liquid flow cavity, the filter body 100 is provided with a first liquid inlet and outlet 140, the filter tube 200 is in communication with the first liquid inlet and outlet 140; the filter body 100 is provided with a second liquid inlet and outlet 150.

[0151] Preferably, the filter body 100 includes a filter shell 110 and two positioning portions 120; the filter shell 110 is provided with the liquid flow cavity, the filter tube 200 is arranged in the filter shell 110, the two positioning portions 120 are arranged at the two ends of the filter shell 110, and the two positioning portions 120 are connected with the two ends of the filter tube 200; the first liquid inlet and outlet 140 is arranged in two, the two first liquid inlet and outlet 140 are arranged on the two positioning portions 120 one by one, and the second liquid inlet and outlet 150 is arranged on the side wall of the filter shell 110. Preferably, the positioning portion 120 includes a positioning plate 122; the positioning plate 122 is arranged in the filter shell 110, the positioning plate 122 is provided with a filter fixing hole, and the filter tube 200 penetrates into the filter fixing hole to fix the filter tube 200.

[0152] When performing the adsorbent coating operation, the adsorbent slurry enters into the filter tube 200 through the first liquid inlet and outlet 140, so that the adsorbent is attached to the inner wall of the filter tube 200. When performing the adsorbent backwashing operation, the backwashing material enters into the liquid flow cavity through the second liquid inlet and outlet 150, the backwashing material impacts on the tube wall of the filter tube 200, so that the tube wall of the filter tube 200 is concave, so that the adsorbent on the inner wall of the filter tube 200 falls off.

[0153] <Dynamic crystallization filtration adsorption process>

[0154] The dynamic crystallization filtration adsorption process is carried out in the dynamic crystallization filtration device described above.

[0155] The dynamic crystallization filtration adsorption process comprises, in sequence, an adsorbent coating operation, a dynamic crystallization filtration adsorption operation and an adsorbent backwashing operation.

[0156] In one embodiment, the adsorbent coating operation is carried out by delivering an adsorbent slurry to the inside of the filter tube and performing a cross-flow filtration operation so that the adsorbent in the adsorbent slurry adheres to the tube wall (preferably the inner wall) of the filter tube, the adsorbent slurry comprising adsorbent and water.

[0157] Preferably, the amount of adsorbent in the adsorbent slurry is 20-200 g / L, preferably 50-150 g / L.

[0158] In one embodiment, the adsorbent coating operation is carried out by continuously delivering an adsorbent slurry to the inside of the filter tube for a coating time and performing a cross-flow filtration operation so that the adsorbent in the adsorbent slurry adheres to the tube wall of the filter tube. Preferably, the coating time is 1-100 min, preferably 3-30 min. Preferably, the flux through the filter membrane tube is 200-800 LMH; preferably 400-600 LMH. Preferably, the ratio of the flow rate through the filter tube to the flow rate through the filter tube is in the range of (0.1:1) to (5:1); preferably (0.2:1) to (0.5:1). Preferably, the coating amount of adsorbent on the inner wall of the filter tube is 160-2400 g / m 2 , preferably 240-400 g / m 2 .

[0159] In the dynamic crystallization filtration adsorption operation, the filtrate obtained by the solid-liquid separation operation of the last stage of the mixed adsorption process is brought into contact with the adsorbent coated on the tube wall of the filter tube (for example, the filtrate is delivered to the inside of the filter tube), and the fluorine in the filtrate is adsorbed by the adsorbent, thereby converting the material after defluorination treatment.

[0160] In a preferred embodiment, the dynamic crystallization filtration device comprises 2 or more groups of dynamic crystallization filtration elements connected in series, wherein each group of dynamic crystallization filtration elements comprises 1 or 2 or more dynamic crystallization filtration elements connected in parallel. In the dynamic crystallization filtration adsorption operation, the filtrate obtained from the solid-liquid separation operation of the last mixed adsorption process is subjected to cross-flow filtration or dead-end filtration in each group of dynamic crystallization filtration elements. Preferably, in the dynamic crystallization filtration adsorption operation, the filtrate obtained from the solid-liquid separation operation of the last mixed adsorption process is subjected to cross-flow filtration in the filter tubes of the first group of dynamic crystallization filtration elements, and then subjected to dead-end filtration in the filter tubes of the other (i.e. the second and subsequent) groups of dynamic crystallization filtration elements. Preferably, the operating flux of the dynamic crystallization filtration elements is 50-200 LMH; preferably 50-150 LMH; in the case of cross-flow filtration, the ratio of the cross-flow flow rate of the feed liquid cross-flowing through the filter tube to the discharge flow rate of the material after defluorination treatment is (1:2)-(1:10); preferably (1:3)-(1:6).

[0161] In the adsorbent backwashing operation, the adsorbent on the pipe wall is backwashed with the backwashing material, and the mixture of the backwashing material and the adsorbent obtained is sent back to the last mixed adsorption process as the discharge material of the dynamic crystallization filtration adsorption process adsorbent backwashing operation. When the process of the present application comprises two or more mixed adsorption processes, the backwashing material is the filtrate obtained from the solid-liquid separation operation of the penultimate mixed adsorption process, and when only the first mixed adsorption process is included, the backwashing material is the defluorination material to be treated.

[0162] In a preferred embodiment, the adsorbent backwashing operation is carried out in the following manner: it comprises three sections (a) backwash, (b) upwash, and (c) downwash, which are carried out in sequence; wherein (a) backwash is to make the backwashing material flow from the outside of the filter tube (i.e. the gap between the inner wall of the filter housing and the outer wall of the filter tube) to the inside (i.e. the internal space of the filter tube); (b) upwash is to make the backwashing material enter from the lower end of the filter tube and flow out from the upper end; (c) downwash is to make the backwashing material enter from the upper end of the filter tube and flow out from the lower end.

[0163] It should be noted that the "upper end" and "lower end" of the filter tube mentioned above are only for distinguishing the two ends of the filter tube in the description, and do not represent the spatial orientation of the two ends.

[0164] In a more preferred embodiment, in the (a) backwash section, the flux of the backwashing material ranges from 1000 to 10000 LMH; preferably 3000 to 5000 LMH; the duration is 3-60 s; preferably 5-10 s;

[0165] In the (b) upwash section, the flow rate of the backwashing material is 10-400 cm / s; preferably 15-25 cm / s; the duration is 5-30 s; preferably 5-10 s;

[0166] (c) in the downwash section, the flow rate of the backwash material is 10-400 cm / s; preferably 15-25 cm / s; and the duration is 5-30 s; preferably 5-10 s;

[0167] The three sections of (a) backwash, (b) upwash, and (c) downwash can be repeated 1-5 times, preferably 1-3 times.

[0168] <Preferred Embodiment>

[0169] The preferred embodiment of the present application is described below in conjunction with the accompanying drawings.

[0170] Preferred embodiment one

[0171] Figure 1 A preferred embodiment of the defluorination process of the present application is shown. It comprises a mixed adsorption unit and a dynamic crystal filtration adsorption process, wherein

[0172] The mixed adsorption unit comprises a first-stage mixed adsorption process, wherein the first-stage mixed adsorption process comprises a mixed adsorption operation I and a solid-liquid separation operation I. In the mixed adsorption operation I, the mixed adsorption feed I is stirred. Then in the solid-liquid separation operation I, the stirred material is subjected to solid-liquid separation using a solid-liquid separation device to obtain a filtrate I and solid waste;

[0173] The mixed adsorption feed I is the effluent material of the adsorbent backwash operation of the dynamic crystal filtration adsorption process;

[0174] The dynamic crystal filtration adsorption process is carried out in a dynamic crystal filtration device, which comprises one or more than two dynamic crystal filtration elements. The dynamic crystal filtration element comprises a tubular filter housing and one or more filter tubes located inside the filter housing. The tube wall of the filter tube is composed of a porous material. The inner wall of the filter housing and the outer wall of the filter tube have a gap for material flow;

[0175] The dynamic crystal filtration adsorption process comprises, in sequence, an adsorbent coating operation, a dynamic crystal filtration adsorption operation, and an adsorbent backwash operation;

[0176] In the adsorbent coating operation, the adsorbent is coated on the tube wall of the filter tube. In the dynamic crystal filtration adsorption operation, the filtrate I is brought into contact with the adsorbent coated on the tube wall of the filter tube, thereby obtaining the defluorinated treated material. In the adsorbent backwash operation, the adsorbent on the tube wall is backwashed using the backwash material S, and the obtained mixture is sent to the first-stage mixed adsorption process as the effluent material of the adsorbent backwash operation. The backwash material S is the defluorination material to be treated;

[0177] The adsorbent is in the form of particles;

[0178] The backwashing is an operation of contacting a backwashing material with the adsorbent so as to make the adsorbent fall off from the filter tube wall of the solid-liquid separation device or the dynamic crystal filter element, thereby obtaining a mixed material comprising the backwashing material and the adsorbent.

[0179] Preferred embodiment two

[0180] Figure 2 Another preferred embodiment of the defluorination process of the present application is shown. It comprises a mixed adsorption unit and a dynamic crystal filter adsorption process, wherein

[0181] The mixed adsorption unit comprises a first-stage mixed adsorption process and a second-stage mixed adsorption process, wherein the first-stage mixed adsorption process comprises a mixed adsorption operation I and a solid-liquid separation operation I, in which the mixed adsorption operation I is performed on a mixed adsorption feed I; and then in the solid-liquid separation operation I, the stirred material is subjected to solid-liquid separation by using a solid-liquid separation device, thereby obtaining a filtrate I and a solid waste;

[0182] The second-stage mixed adsorption process comprises, in sequence, a mixed adsorption operation II, a solid-liquid separation operation II and an adsorbent backwashing operation II; wherein the mixed adsorption operation II is performed on a mixed adsorption feed II; and then in the solid-liquid separation operation II, the stirred material is subjected to solid-liquid separation by using a solid-liquid separation device, thereby obtaining a filtrate II; and then in the adsorbent backwashing operation II, the adsorbent in the solid-liquid separation device is subjected to backwashing by using a backwashing material II, thereby obtaining a mixed material II comprising the backwashing material and the adsorbent;

[0183] The mixed adsorption feed I is the mixed material II, the mixed adsorption feed II is the discharge material of the adsorbent backwashing operation of the dynamic crystal filter adsorption process; and the backwashing material II is a defluorination material to be removed;

[0184] The dynamic crystal filter adsorption process is performed in a dynamic crystal filter device, which comprises one or more than two dynamic crystal filter elements, the dynamic crystal filter element comprises a tubular filter shell and one or more filter tubes located inside the filter shell, the filter tube wall is composed of a porous material; and the inner wall of the filter shell and the outer wall of the filter tube have a gap for material flow;

[0185] The dynamic crystal filter adsorption process comprises, in sequence, an adsorbent coating operation, a dynamic crystal filter adsorption operation and an adsorbent backwashing operation;

[0186] wherein, in the adsorbent coating operation, adsorbent is coated on the tube wall of the filter tube; in the dynamic crystallization filtration adsorption operation, the filtrate II is contacted with the adsorbent coated on the tube wall of the filter tube, thereby obtaining the material after the defluorination treatment; in the adsorbent backwashing operation, the adsorbent on the tube wall is backwashed by using the backwashing material S, and the obtained mixed material is sent to the second-stage mixed adsorption process as the effluent of the adsorbent backwashing operation; the backwashing material S is the filtrate I;

[0187] The adsorbent is in a granular form.

[0188] The backwashing is an operation of contacting a backwashing material with the adsorbent, thereby causing the adsorbent to fall off from the tube wall of the filter tube of the dynamic crystallization filtration element or the solid-liquid separation device, and thereby obtaining a mixed material comprising the backwashing material and the adsorbent.

[0189] Preferred embodiment three

[0190] In another preferred embodiment of the present application, it comprises a mixed adsorption unit and a dynamic crystallization filtration adsorption process, wherein

[0191] The mixed adsorption unit comprises a first-stage mixed adsorption process, a second-stage mixed adsorption process and a third-stage mixed adsorption process, wherein the first-stage mixed adsorption process comprises a mixed adsorption operation I and a solid-liquid separation operation I, in the mixed adsorption operation I, the mixed adsorption feed I is stirred; and then in the solid-liquid separation operation I, the stirred material is subjected to solid-liquid separation by using a solid-liquid separation device, thereby obtaining the filtrate I and solid waste;

[0192] The second-stage mixed adsorption process comprises, in sequence, a mixed adsorption operation II, a solid-liquid separation operation II and an adsorbent backwashing operation II; wherein, in the mixed adsorption operation II, the mixed adsorption feed II is stirred; and then in the solid-liquid separation operation II, the stirred material is subjected to solid-liquid separation by using a solid-liquid separation device, thereby obtaining the filtrate II; and then in the adsorbent backwashing operation II, the adsorbent in the solid-liquid separation device is backwashed by using the backwashing material II, thereby obtaining the mixed material II comprising the backwashing material and the adsorbent;

[0193] The third-stage mixed adsorption process comprises, in sequence, a mixed adsorption operation III, a solid-liquid separation operation III and an adsorbent backwashing operation III; wherein, in the mixed adsorption operation III, the mixed adsorption feed III is stirred; and then in the solid-liquid separation operation III, the stirred material is subjected to solid-liquid separation by using a solid-liquid separation device, thereby obtaining the filtrate III; and then in the adsorbent backwashing operation III, the adsorbent in the solid-liquid separation device is backwashed by using the backwashing material III, thereby obtaining the mixed material III comprising the backwashing material and the adsorbent;

[0194] The mixed adsorption feed I is the mixed material II, the mixed adsorption feed II is the mixed material III, the mixed adsorption feed III is the effluent material of the adsorbent backwashing operation of the dynamic crystal filtration adsorption process; the backwashing material II is the material to be removed fluorine, and the backwashing material III is the filtrate I;

[0195] The dynamic crystal filtration adsorption process is carried out in a dynamic crystal filtration device, and the dynamic crystal filtration device comprises one or more than two dynamic crystal filtration elements, the dynamic crystal filtration element comprises a tubular filter shell and one or more filter tubes located in the filter shell, and the tube wall of the filter tube is composed of a porous material; the inner wall of the filter shell and the outer wall of the filter tube have a gap for material flow;

[0196] The dynamic crystal filtration adsorption process comprises an adsorbent coating operation, a dynamic crystal filtration adsorption operation and an adsorbent backwashing operation in sequence;

[0197] In the adsorbent coating operation, the adsorbent is coated on the tube wall of the filter tube; in the dynamic crystal filtration adsorption operation, the filtrate III is contacted with the adsorbent coated on the tube wall of the filter tube, so as to obtain the fluorine-removed treated material; in the adsorbent backwashing operation, the adsorbent on the tube wall is backwashed by using the backwashing material S, and the obtained mixed material is sent to the third-stage mixed adsorption process as the effluent material of the adsorbent backwashing operation; the backwashing material S is the filtrate II;

[0198] The adsorbent is granular;

[0199] The backwashing is an operation of contacting the backwashing material with the adsorbent, so that the adsorbent falls off from the tube wall of the filter tube of the dynamic crystal filtration element or the solid-liquid separation device, thereby obtaining a mixed material comprising the backwashing material and the adsorbent.

[0200] Preferred embodiment four

[0201] In another preferred embodiment of the application, it comprises a mixed adsorption unit and a dynamic crystal filtration adsorption process, wherein

[0202] The mixed adsorption unit comprises a first-stage mixed adsorption process, a second-stage mixed adsorption process, a third-stage mixed adsorption process and a fourth-stage mixed adsorption process, wherein the first-stage mixed adsorption process comprises a mixed adsorption operation I and a solid-liquid separation operation I, in the mixed adsorption operation I, the mixed adsorption feed I is stirred; then in the solid-liquid separation operation I, the material after stirring is subjected to solid-liquid separation by using a solid-liquid separation device, thereby obtaining the filtrate I and solid waste;

[0203] The second-stage mixed adsorption process sequentially comprises a mixed adsorption operation II, a solid-liquid separation operation II and an adsorbent backwashing operation II; wherein, in the mixed adsorption operation II, the mixed adsorption feed II is stirred; then in the solid-liquid separation operation II, the stirred material is subjected to solid-liquid separation by using a solid-liquid separation device to obtain a filtrate II; then in the adsorbent backwashing operation II, the adsorbent in the solid-liquid separation device is backwashed by using a backwashing material II to obtain a mixed material II containing the backwashing material and the adsorbent;

[0204] The third-stage mixed adsorption process sequentially comprises a mixed adsorption operation III, a solid-liquid separation operation III and an adsorbent backwashing operation III; wherein, in the mixed adsorption operation III, the mixed adsorption feed III is stirred; then in the solid-liquid separation operation III, the stirred material is subjected to solid-liquid separation by using a solid-liquid separation device to obtain a filtrate III; then in the adsorbent backwashing operation III, the adsorbent in the solid-liquid separation device is backwashed by using a backwashing material III to obtain a mixed material III containing the backwashing material and the adsorbent;

[0205] The fourth-stage mixed adsorption process sequentially comprises a mixed adsorption operation IV, a solid-liquid separation operation IV and an adsorbent backwashing operation IV; wherein, in the mixed adsorption operation IV, the mixed adsorption feed IV is stirred; then in the solid-liquid separation operation IV, the stirred material is subjected to solid-liquid separation by using a solid-liquid separation device to obtain a filtrate IV; then in the adsorbent backwashing operation IV, the adsorbent in the solid-liquid separation device is backwashed by using a backwashing material IV to obtain a mixed material IV containing the backwashing material and the adsorbent;

[0206] The mixed adsorption feed I is the mixed material II, the mixed adsorption feed II is the mixed material III, the mixed adsorption feed III is the mixed material IV, and the mixed adsorption feed IV is the discharge material of the adsorbent backwashing operation of the dynamic crystal filtration and adsorption process; the backwashing material II is a fluoride removal material, the backwashing material III is the filtrate I, and the backwashing material IV is the filtrate II;

[0207] The dynamic crystal filtration and adsorption process is carried out in a dynamic crystal filtration device, the dynamic crystal filtration device comprises one or more than two dynamic crystal filtration elements, the dynamic crystal filtration element comprises a tubular filter housing and one or more filter tubes located inside the filter housing, the tube wall of the filter tube is composed of a porous material; the inner wall of the filter housing and the outer wall of the filter tube have a gap for material flow;

[0208] The dynamic crystal filtration and adsorption process sequentially comprises an adsorbent coating operation, a dynamic crystal filtration and adsorption operation and an adsorbent backwashing operation;

[0209] In the adsorbent coating operation, the adsorbent is coated on the tube wall of the filter tube; in the dynamic crystallization filtration adsorption operation, the filtrate IV is contacted with the adsorbent coated on the tube wall of the filter tube, so as to obtain the material after the defluorination treatment; in the adsorbent backwashing operation, the adsorbent on the tube wall is backwashed by using the backwashing material S, and the obtained mixed material is sent to the third-stage mixed adsorption process as the effluent material of the adsorbent backwashing operation; the backwashing material S is the filtrate III.

[0210] The adsorbent is in a granular form.

[0211] The backwashing is an operation of contacting the backwashing material with the adsorbent, so that the adsorbent is detached from the tube wall of the filter tube of the dynamic crystallization filtration element or the solid-liquid separation device, thereby obtaining a mixed material comprising the backwashing material and the adsorbent.

[0212] Embodiment

[0213] The following specific examples are listed to further illustrate the present application. It should be understood that these examples are intended to illustrate the present application and are not intended to limit the scope of the present application. In addition, it should be understood that after reading the disclosure of the present application, those skilled in the art can make various modifications or changes to the present application, and these equivalent forms also fall within the scope of the present application.

[0214] Preparation of adsorbent raw material

[0215] The adsorbent raw material is prepared according to the method described in Example 1 of CN110732305A.

[0216] Specifically, 4L of 4M / L NaOH solution is prepared. 1.665kg of aluminum sulfate is weighed and poured into a container containing 10L of tap water while stirring. The pH of the solution is continuously measured using a pH meter until it stabilizes. The prepared 4M / L NaOH solution is slowly poured into the solution while continuously stirring with a stirrer at a speed of 150RPM, and the solution is uniformly mixed by stirring while observing the pH meter to make the pH value reach 6. The NaOH solution is continuously added until the pH value of the final solution reaches the range of 7±0.5. Tap water is added to the container until the total volume of the solution in the container reaches 15L. The temperature of the solution in the container is raised to 95℃ within one hour, and then the temperature is maintained for 12 hours. After the temperature maintenance is completed, the container is taken out and cooled to obtain the adsorbent raw material.

[0217] Example 1

[0218] The fluorine-containing material generated in the battery recycling process has a fluorine content of 103.0mg / L, and needs to be defluorinated under neutral conditions to reduce the fluorine content to within 5mg / L.

[0219] To solve the above problems, in this embodiment, the process of the preferred embodiment two of the present application is simulated under laboratory conditions to remove fluorine from the fluorine-containing material produced in the battery process with a fluorine content of 103.0 mg / L under neutral conditions, and the process flow is as shown in Figure 2

[0220] (a-1) Preparation of samples

[0221] First, the fluorine-containing material to be defluorinated with a fluorine content of 103.0 mg / L is prepared, and a portion of it is pretreated to a fluorine content of 49.92 mg / L.

[0222] Then, 200 mL of the material pretreated to a fluorine content of 49.92 mg / L is placed in a 250 mL beaker, and a sulfuric acid solution with a concentration of 0.1%, 1%, 5%, and 10% is used to adjust the pH to neutral (6.98) for standby (hereinafter referred to as "pretreated material").

[0223] (b-1) Adsorbent coating

[0224] The filter box (Pall online filter PN1119) is disassembled, and the inside and outside of the box and the matching hose are washed with tap water and then rinsed with pure water. Then, a tubular membrane slice (hydrophilic microporous filter membrane Millipore NY05047005, pore size 5 μm, diameter 47 mm) is loaded into the filter box as a carrier for the adsorbent, and the effective area is 0.000855 m 2 Then, the filter box is assembled; after the filter box is assembled, the air in the filter box is purged with pure water.

[0225] Take 2.6 mL of adsorbent raw material with a concentration of 80 g / L, and prepare a slurry with 10 mL of pure water. Then, the adsorbent slurry obtained by slurry preparation is uniformly injected into the filter box for adsorbent coating, and the effective coating amount at this time is 243.3 g / m 2 .

[0226] The two filter boxes are coated with adsorbent according to the above method, and the two filter boxes are connected in series using a hose. The filter box is fixed on an iron stand and connected to a peristaltic pump with a hose, and then pure water is taken and pumped into the filter box through the peristaltic pump, and then filtered out. The flow rate of the pumped liquid is adjusted to 100 LMH (about 1.42 mL / min), and the peristaltic pump is run continuously for 30 min to make the adsorbent firmly coated in the filter box, and then the peristaltic pump is paused.

[0227] (c-1) Dynamic crystallization filtration process simulation

[0228] ​The pretreated material (filtrate obtained by solid-liquid separation in the simulated mixed adsorption process) is placed in front of the peristaltic pump, a hose is placed at the bottom of the beaker, and the peristaltic pump is turned on. To ensure the accuracy of the data, 15 mL of the previous filtered material is discarded, and then the treated material is received. After the pretreated material is completely treated, the fluorine content of the treated material is detected, which is between 4.37 mg / L, fully meeting the treatment requirements.

[0229] (d-1) Adsorbent backwashing + mixed adsorption process simulation

[0230] Take 200 mL of the material to be defluorinated and place it in a 250 mL beaker. Add 0.1% to 10% sulfuric acid solution to adjust the pH to neutral (7.02) for standby use.

[0231] Take the used adsorbent filter cake in the two-stage filter box in the dynamic crystallization filtration process (c-1), transfer it to the prepared material to be defluorinated, and then perform magnetic stirring. In the first 15s to 30s, the stirring causes the adsorbent filter cake to disperse in the material to be defluorinated. Continue stirring and monitor the pH value of the system. Adjust it to around pH 7 by adding 0.1% to 10% sulfuric acid solution. After 30 minutes of stirring, use a 0.45 μm filter membrane to perform suction filtration to separate the adsorbent from the treated material. The fluorine content of the treated material is 49.3 mg / L. Place the treated material in a 250 mL beaker for subsequent use. Based on the amount of treated material, the adsorbent dosage at this time (based on the volume of the material to be defluorinated) is 2.08 g / L.

[0232] (e-1) Dynamic crystallization filtration process simulation

[0233] The treated material obtained in (d-1) is treated in the same way as (c-1) above, and the further treated material has a fluorine content of 3.94 mg / L, which is consistent with the treated material in (c-1) above.

[0234] The simulation experiment of this embodiment shows that the process of the application can treat the fluorine content from the initial 103 mg / L to 3.94 mg / L.

[0235] Example 2

[0236] Some new energy companies need to remove fluorine ions before recovering battery precious metals. The fluorine content of their material to be defluorinated is 550 mg / L to 600 mg / L, the pH is neutral to alkaline, and the removal of fluorine is required under neutral conditions without affecting other metal ions. The fluorine content after treatment is expected to be below 3 mg / L.

[0237] Therefore, in this embodiment, the defluorination process of the preferred embodiment one of the present application was simulated in laboratory conditions to treat a defluorination material with a fluorine content of 581.9 mg / L and a neutral pH (7.19) under neutral conditions. The process flow is shown in Figure 3

[0238] The membrane column used in this embodiment is a liquid treatment device described in the applicant's prior patent application CN110304701A.

[0239] (a-2) Preparation of samples

[0240] The defluorination material with a fluorine content of 581.9 mg / L was taken.

[0241] A portion of the defluorination material was pretreated to a fluorine content of 159.0 mg / L, and the pH was adjusted to neutral using a 0.1% to 10% sulfuric acid solution for standby (hereinafter referred to as "pretreated sample A").

[0242] A portion of the filtrate was pretreated to a fluorine content of 49.65 mg / L, and the pH was adjusted to neutral using a 0.1% to 10% sulfuric acid solution for standby (hereinafter referred to as "pretreated sample B").

[0243] (b-2) Adsorbent coating

[0244] Test device setup: two identical membrane columns were taken, and the effective area of the filter tube in a single column was 0.0435 m 2 The two membrane columns were connected in series.

[0245] 180 mL of adsorbent raw material with a concentration of 80 g / L was taken, diluted with tap water to 1 L, and the concentration was 14.4 g / L to obtain an adsorbent slurry. The adsorbent slurry was placed in a beaker and stirred, and the adsorbent slurry was fed into the membrane tube through a large peristaltic pump, the circulation flow rate was adjusted to 360 mL / min, and the outlet flow rate was 180 mL / min. The adsorbent coating of the membrane tube was carried out, the coating time was 5 min, and the coating amount was 240 g / m 2 Two membrane tubes were coated with adsorbents in the same way.

[0246] (c-2) Dynamic crystallization filtration adsorption process simulation

[0247] (c-2-1) Dynamic crystallization filtration adsorption operation simulation

[0248] ​Take 4.4 L of pretreated sample B (simulating the filtrate obtained by solid-liquid separation in the second-stage mixed adsorption process) and place it in a beaker, and send it into the membrane tube through a peristaltic pump. Adjust the peristaltic pump to make the circulating flow rate 360 mL / min and the water outlet flow rate 72 mL / min (100 LMH). In the initial stage, the circulating pump is first kept closed for 15 s, and then opened after 15 s to process the sample. During the operation, take samples at random to determine the fluorine content of the processed sample, which fluctuates between 0.5 mg / L and 2.5 mg / L. When 4.4 L of pretreated sample B is processed, determine the fluorine content of the total processed sample, which is 2 mg / L.

[0249] (c-2-2) Backwashing simulation

[0250] Use 4.4 L of pretreated sample A (simulating the filtrate obtained by solid-liquid separation in the first-stage mixed adsorption process) to backwash the membrane column. The flow rate of the backwashing pump is controlled at about 2850 mL / min, first perform side water outlet backflush, open the upper and lower water outlet valves, flush for 9 s; then perform flushing from bottom to top, close the side water outlet, open the upper water outlet, flush for 7 s; then perform flushing from top to bottom, close the side water outlet, open the lower water outlet, flush for 7 s; this is the first backwashing step. Then perform the second backwashing step in the same way as the first backwashing step. After backwashing, the residual water in the column is emptied.

[0251] (d-2) Second-stage mixed adsorption process simulation

[0252] (d-2-1) Mixed adsorption operation

[0253] Collect the material discharged from the water outlet during the backwashing process in (c-2-2) into a container and stir it. Monitor the pH during stirring and adjust it to about 7 by using sulfuric acid. Take a sample after stirring for 30 min to detect the fluorine content, which is 45.3 mg / L.

[0254] (d-2-2) Solid-liquid separation operation

[0255] Use the two membrane columns in series in (b-2) to perform solid-liquid separation on the material obtained in (d-2-1), control the total flow rate at about 450 mL / min, close the upper circulating port valve, and perform dead-end filtration separation. The obtained filtrate is reserved for subsequent use, which is referred to as "filtrate d" hereinafter.

[0256] (d-2-3) Adsorbent backwashing

[0257] Use the water sample to be processed to perform adsorbent backwashing operation in the membrane column in the same way as (c-2-2). After completion, the residual water in the column is emptied.

[0258] (e-2) First stage mixed adsorption process simulation

[0259] (e-2-1) Mixed adsorption operation

[0260] The material discharged during the backwashing process of (d-2-3) was collected in a container and stirred, and the pH was monitored during the stirring process. The pH was controlled at about 7 by adjusting with sulfuric acid. After stirring for 30 min, the sample was detected for fluorine content, and the fluorine content was 121.2 mg / L.

[0261] (e-2-2) Solid-liquid separation operation

[0262] The material obtained in (e-2-1) was subjected to solid-liquid separation using two membrane columns in series in (b-2), and the total flow rate was controlled at about 450 mL / min, the up-circulation valve was closed, and dead-end filtration separation was performed. The obtained filtrate was reserved for subsequent use, and the filtrate is hereinafter referred to as "filtrate e".

[0263] (f-2) Dynamic crystallization and filtration adsorption process simulation

[0264] A new adsorbent slurry was taken and coated in the same way as (b-2), and the filtrate d obtained in (d-2) was treated in the same way as (c-2-1), and the fluorine content of the treated sample was 1.5 mg / L, which was consistent with the data of (c-2-1).

[0265] The filtrate e obtained in (e-2-2) was subjected to backwashing operation of the adsorbent in the membrane column in the same way as (c-2-2).

[0266] (g-2) Second stage mixed adsorption process simulation

[0267] The material discharged during the backwashing process of (f-2) was collected in a container and stirred, and the pH was monitored during the stirring process. The pH was controlled at about 7 by adjusting with sulfuric acid. After stirring for 30 min, the sample was detected for fluorine content, and the fluorine content was 35 mg / L.

[0268] Solid-liquid separation was performed in the same way as (e-2-2), and the obtained filtrate was reserved for subsequent use, and the filtrate is hereinafter referred to as "filtrate g".

[0269] The material to be defluorinated was subjected to backwashing operation of the adsorbent in the membrane column in the same way as (d-2-2).

[0270] (h-2) First stage mixed adsorption process simulation

[0271] The material discharged in the backwashing process of (g-2) is collected into a container and stirred, and the pH is monitored during the stirring process, and the pH is controlled at about 7 by adjusting with sulfuric acid. After stirring for 30 min, the fluorine content is detected by sampling, and the content is about 120 mg / L.

[0272] Solid-liquid separation is carried out in the same way as in (e-2-2), and the obtained filtrate is left for subsequent use.

[0273] Thus, the cycle experiment is carried out, and the overall accounting shows that the concentration of adsorbent used by each batch is 4.75 g / L, and the fluorine content is reduced from the initial 581.9 mg / L to about 2 mg / L.

[0274] Industrial applicability

[0275] The defluorination process of the present application can be widely used in industry, especially in the lithium battery recycling industry for defluorination treatment of fluorine-containing materials.

Claims

1. A defluorination process, characterized in that, a process for reducing the fluorine content in a material to be defluorinated to obtain a defluorinated material, wherein... It includes a hybrid adsorption unit and a dynamic crystal filtration adsorption process, wherein The mixed adsorption unit includes a first-stage mixed adsorption process, wherein the first-stage mixed adsorption process includes a mixed adsorption operation I and a solid-liquid separation operation I. In the mixed adsorption operation I, the mixed adsorption feed I is stirred; then in the solid-liquid separation operation I, the stirred material is separated into solid and liquid by a solid-liquid separation device to obtain filtrate I and solid waste. The mixed adsorption feed I is the discharge material from the adsorbent backwashing operation of the dynamic crystal filtration adsorption process. The dynamic crystal filtration adsorption process is carried out in a dynamic crystal filtration device, which includes one or more dynamic crystal filtration elements. Each dynamic crystal filtration element includes a tubular filter housing and one or more filter tubes located inside the filter housing. The walls of the filter tubes are made of porous material. There is a gap between the inner wall of the filter housing and the outer wall of the filter tubes to allow material flow. The dynamic crystal filtration adsorption process includes, in sequence, an adsorbent coating operation, a dynamic crystal filtration adsorption operation, and an adsorbent backwashing operation; In the adsorbent coating operation, the adsorbent is coated onto the wall of the filter tube; in the dynamic crystal filtration adsorption operation, the filtrate I is brought into contact with the adsorbent coated on the wall of the filter tube to obtain the defluorinated material; in the adsorbent backwashing operation, the adsorbent on the tube wall is backwashed using backwash material S, and the resulting mixture is sent to the first-stage mixing adsorption process as the discharge material of the adsorbent backwashing operation; the backwash material S is the material to be defluorinated. The adsorbent is in granular form; The backwashing process involves bringing the backwash material into contact with the adsorbent, thereby causing the adsorbent to detach from the wall of the filter tube of the solid-liquid separation device or dynamic crystal filter element, resulting in a mixture of the backwash material and the adsorbent.

2. A defluorination process, characterized in that, a process for reducing the fluorine content in a material to be defluorinated to obtain a defluorinated material, wherein... It includes a hybrid adsorption unit and a dynamic crystal filtration adsorption process, wherein The mixed adsorption unit includes a first-stage mixed adsorption process and a second-stage mixed adsorption process. The first-stage mixed adsorption process includes a mixed adsorption operation I and a solid-liquid separation operation I. In the mixed adsorption operation I, the mixed adsorption feed I is stirred. Then, in the solid-liquid separation operation I, a solid-liquid separation device is used to separate the stirred material into solid and liquid, resulting in filtrate I and solid waste. The second-stage mixed adsorption process sequentially includes mixed adsorption operation II, solid-liquid separation operation II, and adsorbent backwashing operation II. In mixed adsorption operation II, the mixed adsorption feed II is stirred. Then, in solid-liquid separation operation II, a solid-liquid separation device is used to separate the stirred material into solid and liquid components, yielding filtrate II. Finally, in adsorbent backwashing operation II, the backwash material II is used to backwash the adsorbent in the solid-liquid separation device, resulting in a mixture II containing the backwash material and the adsorbent. Wherein, the mixed adsorption feed I is mixed feed II, the mixed adsorption feed II is the discharged material from the backwashing operation of the adsorbent in the dynamic crystal filtration adsorption process; the backwash material II is the material to be defluorinated; The dynamic crystal filtration adsorption process is carried out in a dynamic crystal filtration device, which includes one or more dynamic crystal filtration elements. Each dynamic crystal filtration element includes a tubular filter housing and one or more filter tubes located inside the filter housing. The walls of the filter tubes are made of porous material. There is a gap between the inner wall of the filter housing and the outer wall of the filter tubes to allow material flow. The dynamic crystal filtration adsorption process includes, in sequence, an adsorbent coating operation, a dynamic crystal filtration adsorption operation, and an adsorbent backwashing operation; In the adsorbent coating operation, the adsorbent is coated onto the wall of the filter tube; in the dynamic crystal filtration adsorption operation, the filtrate II is brought into contact with the adsorbent coated on the wall of the filter tube to obtain the defluorinated material; in the adsorbent backwashing operation, the adsorbent on the tube wall is backwashed using backwash material S, and the resulting mixture is sent to the second-stage mixing adsorption process as the discharge material of the adsorbent backwashing operation; the backwash material S is filtrate I. The adsorbent is in granular form; The backwashing process involves bringing the backwash material into contact with the adsorbent, thereby causing the adsorbent to detach from the wall of the filter tube of the solid-liquid separation device or dynamic crystal filter element, resulting in a mixture of the backwash material and the adsorbent.

3. A defluorination process, characterized in that, a process for reducing the fluorine content in a material to be defluorinated to obtain a defluorinated material, wherein... It includes a hybrid adsorption unit and a dynamic crystal filtration adsorption process, wherein The mixed adsorption unit includes a first-stage mixed adsorption process, a second-stage mixed adsorption process, and a third-stage mixed adsorption process. The first-stage mixed adsorption process includes a mixed adsorption operation I and a solid-liquid separation operation I. In the mixed adsorption operation I, the mixed adsorption feed I is stirred. Then, in the solid-liquid separation operation I, a solid-liquid separation device is used to separate the stirred material into solid and liquid, resulting in filtrate I and solid waste. The second-stage mixed adsorption process sequentially includes mixed adsorption operation II, solid-liquid separation operation II, and adsorbent backwashing operation II. In mixed adsorption operation II, the mixed adsorption feed II is stirred. Then, in solid-liquid separation operation II, a solid-liquid separation device is used to separate the stirred material into solid and liquid components, yielding filtrate II. Finally, in adsorbent backwashing operation II, the backwash material II is used to backwash the adsorbent in the solid-liquid separation device, resulting in a mixture II containing the backwash material and the adsorbent. The third-stage mixed adsorption process sequentially includes mixed adsorption operation III, solid-liquid separation operation III, and adsorbent backwashing operation III. In mixed adsorption operation III, the mixed adsorption feed III is stirred. Then, in solid-liquid separation operation III, the stirred material is separated into solid and liquid components using a solid-liquid separation device to obtain filtrate III. Then, in adsorbent backwashing operation III, the adsorbent in the solid-liquid separation device is backwashed using backwash material III to obtain a mixture III containing the backwash material and the adsorbent. Wherein, the mixed adsorption feed I is mixed feed II, the mixed adsorption feed II is mixed feed III, and the mixed adsorption feed III is the discharged material from the backwashing operation of the adsorbent in the dynamic crystal filtration adsorption process; the backwash material II is the material to be defluorinated, and the backwash material III is filtrate I; The dynamic crystal filtration adsorption process is carried out in a dynamic crystal filtration device, which includes one or more dynamic crystal filtration elements. Each dynamic crystal filtration element includes a tubular filter housing and one or more filter tubes located inside the filter housing. The walls of the filter tubes are made of porous material. There is a gap between the inner wall of the filter housing and the outer wall of the filter tubes to allow material flow. The dynamic crystal filtration adsorption process includes, in sequence, an adsorbent coating operation, a dynamic crystal filtration adsorption operation, and an adsorbent backwashing operation; In the adsorbent coating operation, the adsorbent is coated onto the wall of the filter tube; in the dynamic crystal filtration adsorption operation, the filtrate III is brought into contact with the adsorbent coated on the wall of the filter tube to obtain the defluorinated material; in the adsorbent backwashing operation, the adsorbent on the tube wall is backwashed using backwash material S, and the resulting mixture is sent to the third-stage mixing adsorption process as the discharge material of the adsorbent backwashing operation; the backwash material S is filtrate II. The adsorbent is in granular form; The backwashing process involves bringing the backwash material into contact with the adsorbent, thereby causing the adsorbent to detach from the wall of the filter tube of the solid-liquid separation device or dynamic crystal filter element, resulting in a mixture of the backwash material and the adsorbent.

4. A defluorination process, characterized in that, a process for reducing the fluorine content in a material to be defluorinated to obtain a defluorinated material, wherein... It includes a hybrid adsorption unit and a dynamic crystal filtration adsorption process, wherein The mixed adsorption unit includes a first-stage mixed adsorption process, a second-stage mixed adsorption process, a third-stage mixed adsorption process, and a fourth-stage mixed adsorption process. The first-stage mixed adsorption process includes a mixed adsorption operation I and a solid-liquid separation operation I. In the mixed adsorption operation I, the mixed adsorption feed I is stirred. Then, in the solid-liquid separation operation I, a solid-liquid separation device is used to separate the stirred material into solid and liquid, resulting in filtrate I and solid waste. The second-stage mixed adsorption process sequentially includes mixed adsorption operation II, solid-liquid separation operation II, and adsorbent backwashing operation II. In mixed adsorption operation II, the mixed adsorption feed II is stirred. Then, in solid-liquid separation operation II, a solid-liquid separation device is used to separate the stirred material into solid and liquid components, yielding filtrate II. Finally, in adsorbent backwashing operation II, the backwash material II is used to backwash the adsorbent in the solid-liquid separation device, resulting in a mixture II containing the backwash material and the adsorbent. The third-stage mixed adsorption process sequentially includes mixed adsorption operation III, solid-liquid separation operation III, and adsorbent backwashing operation III. In mixed adsorption operation III, the mixed adsorption feed III is stirred. Then, in solid-liquid separation operation III, the stirred material is separated into solid and liquid components using a solid-liquid separation device to obtain filtrate III. Then, in adsorbent backwashing operation III, the adsorbent in the solid-liquid separation device is backwashed using backwash material III to obtain a mixture III containing the backwash material and the adsorbent. The fourth stage of mixed adsorption process includes, in sequence, mixed adsorption operation IV, solid-liquid separation operation IV, and adsorbent backwashing operation IV; wherein, in mixed adsorption operation IV, the mixed adsorption feed IV is stirred; then, in solid-liquid separation operation IV, the stirred material is separated into solid and liquid by a solid-liquid separation device to obtain filtrate IV; then, in adsorbent backwashing operation IV, the adsorbent in the solid-liquid separation device is backwashed by the backwash material IV to obtain a mixture IV containing the backwash material and the adsorbent; Wherein, the mixed adsorption feed I is mixed feed II, the mixed adsorption feed II is mixed feed III, the mixed adsorption feed III is mixed feed IV, and the mixed adsorption feed IV is the discharged material from the backwashing operation of the adsorbent in the dynamic crystal filtration adsorption process; the backwash material II is the material to be defluorinated, the backwash material III is filtrate I, and the backwash material IV is filtrate II. The dynamic crystal filtration adsorption process is carried out in a dynamic crystal filtration device, which includes one or more dynamic crystal filtration elements. Each dynamic crystal filtration element includes a tubular filter housing and one or more filter tubes located inside the filter housing. The walls of the filter tubes are made of porous material. There is a gap between the inner wall of the filter housing and the outer wall of the filter tubes to allow material flow. The dynamic crystal filtration adsorption process includes, in sequence, an adsorbent coating operation, a dynamic crystal filtration adsorption operation, and an adsorbent backwashing operation; In the adsorbent coating operation, the adsorbent is coated onto the wall of the filter tube; in the dynamic crystal filtration adsorption operation, the filtrate IV is brought into contact with the adsorbent coated on the wall of the filter tube to obtain the defluorinated material; in the adsorbent backwashing operation, the adsorbent on the tube wall is backwashed using backwash material S, and the resulting mixture is sent to the fourth-stage mixing adsorption process as the discharge material of the adsorbent backwashing operation; the backwash material S is filtrate III. The adsorbent is in granular form; The backwashing process involves bringing the backwash material into contact with the adsorbent, thereby causing the adsorbent to detach from the wall of the filter tube of the solid-liquid separation device or dynamic crystal filter element, resulting in a mixture of the backwash material and the adsorbent.

5. The defluorination process according to claim 4, characterized in that, The solid-liquid separation device in the first stage of mixed adsorption process is a plate and frame filter press or a centrifugal separator; the solid-liquid separation device in the second to fourth stages of mixed adsorption process is a dynamic crystal filter element.

6. The defluorination process according to any one of claims 1 to 4, characterized in that, The adsorbent is selected from one or more oxides of aluminum, zirconium, titanium, magnesium, iron, lanthanum, or their composite oxides; the particle size of the adsorbent is 0.1~50 μm; in the adsorbent coating operation, the amount of adsorbent coated on the inner wall of the filter tube is 20~2400 g / m. 2 .

7. The defluorination process according to claim 6, characterized in that, The adsorbent has a particle size of 0.5~5 μm, and in the adsorbent coating operation, the amount of adsorbent coated on the inner wall of the filter tube is 100~400 g / m. 2 .

8. The defluorination process according to any one of claims 1 to 4, characterized in that, The adsorbent coating operation is performed by conveying an adsorbent slurry into the filter tube and performing a cross-flow filtration operation to allow the adsorbent to adhere to the tube wall. The adsorbent slurry contains adsorbent and water.

9. The defluorination process according to any one of claims 1 to 4, characterized in that, The dynamic crystal filtration device includes one or more sets of dynamic crystal filter elements connected in series, wherein each set of dynamic crystal filter elements includes one or more dynamic crystal filter elements connected in parallel; in the dynamic crystal filtration adsorption operation, the filtrate obtained from the solid-liquid separation operation of the last stage mixing adsorption process is subjected to cross-flow filtration in all sets of dynamic crystal filter elements, or to dead-end filtration in all sets of dynamic crystal filter elements, or to cross-flow filtration in some sets of dynamic crystal filter elements and dead-end filtration in other sets of dynamic crystal filter elements.

10. The defluorination process according to claim 9, characterized in that, The operating throughput of the dynamic crystal filter element is 50~200 LMH; in the case of cross-flow filtration, the ratio of the cross-flow flow rate of the feed liquid through the filter tube to the discharge flow rate of the defluorinated material is (1:2)~(1:10).

11. The defluorination process according to claim 10, characterized in that, The operating throughput of the dynamic crystal filter element is 50-150 LMH; in the case of cross-flow filtration, the ratio of the cross-flow flow rate of the feed liquid through the filter tube to the discharge flow rate of the defluorinated material is (1:3) to (1:6).

12. The defluorination process according to any one of claims 1 to 4, characterized in that, The adsorbent backwashing operation in the dynamic crystal filtration adsorption process is performed in the following manner: It includes three sequential processes: (a) backwashing, (b) top flushing, and (c) bottom flushing; wherein, (a) backwashing is to allow the backwash material to flow from the outside of the filter tube to its inside; (b) top flushing is to allow the backwash material to enter from the bottom of the filter tube and flow out from the top; and (c) bottom flushing is to allow the backwash material to enter from the top of the filter tube and flow out from the bottom.

13. The defluorination process according to claim 12, characterized in that, (a) In the backwash section, the flow rate of the backwash material ranges from 1,000 to 10,000 LMH; the duration is 3 to 60 seconds. (b) In the backwashing section, the flow rate of the backwash material is 10~400 cm / s; the duration is 5~30s. (c) In the downwash section, the flow rate of the backwash material is 10~400 cm / s; the duration is 5~30s; The three processes (a) backflush, (b) upward stroke, and (c) downward stroke can be repeated 1 to 5 times.

14. The defluorination process according to claim 13, characterized in that, (a) In the backwash section, the flow rate of the backwash material ranges from 3000 to 5000 LMH; the duration is 5 to 10 seconds. (b) In the backwashing section, the flow rate of the backwash material is 15~25 cm / s; the duration is 5~10s. (c) In the downwash section, the flow rate of the backwash material is 15~25 cm / s; the duration is 5~10s; The three processes (a) backflush, (b) upward stroke, and (c) downward stroke can be repeated 1 to 3 times.

15. The defluorination process according to any one of claims 1 to 4, characterized in that, The pH of the material to be defluorinated is 5-9, and the pH of the filtrate is controlled to be 5-9 in at least one solid-liquid separation operation.

16. The defluorination process according to any one of claims 1 to 4, characterized in that, The discharge materials from the process are only the defluorination treated material and the solid waste obtained in solid-liquid separation operation I.

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