Method and system for recovery treatment of phenol-containing organic phosphoric acid waste liquid

Abstract

The application provides a recovery treatment method and system of phenol-containing organic phosphoric acid waste liquid, and the recovery treatment method comprises the following steps: mixing the phenol-containing organic phosphoric acid waste liquid to be treated with an extractant to perform extraction treatment, so as to obtain an extraction phase and a raffinate phase, and the raffinate phase comprises nitrogen-containing organic cations and phosphate; performing extractant removal treatment on the extraction phase to obtain phenolic compounds; performing oxidation treatment on the raffinate phase by using an oxidizing agent to degrade the nitrogen-containing organic cations, so as to obtain a gas phase component and a liquid phase component; and collecting the liquid phase component to obtain reusable phosphoric acid. The recovery treatment method provided by the application can efficiently recover phenolic organic matters and high-purity phosphoric acid in the phosphoric acid waste liquid, reduces the treatment cost, and realizes resource recycling.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of organic phosphoric acid waste liquid treatment, and particularly relates to a recovery treatment method and system of phenol-containing organic phosphoric acid waste liquid. BACKGROUND

[0002] The phenol-containing organic phosphoric acid waste liquid mainly comes from coal chemical industry, petroleum chemical industry, coking industry and other industrial industries. Traditional waste phosphoric acid treatment mostly adopts incineration or neutralization method, which leads to waste of phosphoric acid resources, ineffective recovery of organic matter, and high treatment cost and easy secondary pollution.

[0003] Therefore, a new treatment method is urgently needed to solve the above problems. SUMMARY

[0004] The application provides a recovery treatment method and system of phenol-containing organic phosphoric acid waste liquid, which can efficiently recover phenolic organic matter and high-purity phosphoric acid in the phosphoric acid waste liquid, reduce the treatment cost, and realize resource recycling.

[0005] In a first aspect, the application provides a recovery treatment method of phenol-containing organic phosphoric acid waste liquid, which comprises: mixing the phenol-containing organic phosphoric acid waste liquid to be treated with an extractant for extraction treatment to obtain an extraction phase and a raffinate phase, the raffinate phase containing nitrogen-containing organic cations and phosphate; performing a desorption treatment on the extraction phase to obtain a phenolic compound; performing an oxidation treatment on the raffinate phase using an oxidizing agent to degrade the nitrogen-containing organic cations to obtain a gas phase component and a liquid phase component; and collecting the liquid phase component to obtain reusable phosphoric acid.

[0006] According to the embodiments of the first aspect of the application, the extraction treatment of the phenol-containing organic phosphoric acid waste liquid to be treated with the extractant to obtain the extraction phase and the raffinate phase comprises the following sub-steps: mixing the phenol-containing organic phosphoric acid waste liquid with the extractant at a temperature of 50-100 DEG C to obtain a mixed liquid; stirring the mixed liquid for a first preset time, and separating the extraction phase and the raffinate phase after standing and layering; and repeating each sub-step of the extraction treatment at least once.

[0007] According to the embodiments of the first aspect of the application, the extractant comprises one or more of alkane compounds, aromatic compounds, ether compounds, ester compounds and ketone compounds.

[0008] According to the embodiments of the first aspect of the application, the mass ratio of the phenol-containing organic phosphoric acid waste liquid to the extractant is (2-6):1.

[0009] According to the embodiments of the first aspect of the application, the step of mixing the raffinate phase with the oxidizing agent to obtain the gas phase component and the liquid phase component comprises:

[0010] The oxidizing agent is introduced into the raffinate phase under the temperature condition of 120-160 DEG C, and the oxidation reaction lasts for a second preset time.

[0011] According to the embodiment of the first aspect of the present application, the oxidizing agent comprises one or more of hydrogen peroxide, hydrogen dioxide, oxygen and ozone; optionally, the concentration of the hydrogen peroxide is greater than or equal to 25%.

[0012] According to the embodiment of the first aspect of the present application, the gas phase component is collected by absorption, and the gas phase component comprises carbon dioxide and nitrogen dioxide.

[0013] According to the embodiment of the first aspect of the present application, the step of collecting the gas phase component by absorption comprises: passing the gas phase component through multiple stages of clean water to obtain a first absorption liquid and residual gas; and passing the residual gas through multiple stages of alkali solution to obtain a second absorption liquid.

[0014] According to the embodiment of the first aspect of the present application, the step of collecting the liquid phase component to obtain reusable phosphoric acid comprises: collecting the liquid phase component; and concentrating the liquid phase component to obtain the reusable phosphoric acid.

[0015] According to the embodiment of the first aspect of the present application, the phenol-containing organic phosphoric acid waste liquid comprises the following components by mass fraction: moisture 2-4%, phenolic compounds 8-10%, basic nitrogen compounds 12-14%, and phosphoric acid radicals 74-78%.

[0016] In the second aspect, the present application provides a recovery treatment system for a phenol-containing organic phosphoric acid waste liquid, comprising: an extraction device configured to receive a phenol-containing organic phosphoric acid waste liquid and an extraction agent, extract phenolic compounds in the phenol-containing organic phosphoric acid waste liquid by the extraction agent, and separate to obtain an extraction phase and a raffinate phase; a separation device connected to the extraction device, configured to receive the extraction phase, and perform desolventization treatment on the extraction phase; an oxidation device connected to the extraction device, configured to receive the raffinate phase and an oxidizing agent to perform an oxidation reaction; and a gas absorption device connected to the oxidation device, configured to receive a gas phase component generated by the oxidation reaction and perform absorption collection.

[0017] According to the embodiment of the second aspect of the present application, the recovery treatment system further comprises a concentration device connected to the oxidation device, configured to receive a liquid phase component after the oxidation reaction, and perform concentration on the liquid phase component.

[0018] The recovery treatment method for the phenol-containing organic phosphoric acid waste liquid according to the embodiment of the present application selectively separates phenolic compounds by an extraction agent, oxidizes and degrades nitrogen-containing organic cations by an oxidizing agent, and the remaining phosphoric acid can be recycled, which can avoid the generation of solid waste, and efficiently recycle phenolic organic matter and high-purity phosphoric acid in waste phosphoric acid, thereby reducing the treatment cost and realizing resource recycling. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly introduced. Those drawings can help the ordinary skilled in the art to obtain other drawings without creative effort.

[0020] Figure 1 The flow chart of the recovery treatment method of the phenol-containing organic phosphoric acid waste liquid provided in the embodiments of the present application is shown in the figure.

[0021] Figure 2 The specific flow chart of step S100 in the embodiments of the present application is shown in the figure. Figure 1

[0022] Figure 3 The specific flow chart of step S400 in the embodiments of the present application is shown in the figure. Figure 1

[0023] Figure 4 The connection schematic diagram of the recovery treatment system of the phenol-containing organic phosphoric acid waste liquid provided in the embodiments of the present application is shown in the figure.

[0024] Reference signs:

[0025] 100, extraction device; 200, separation device; 300, oxidation device; 400, gas absorption device; 401, carbon dioxide absorption device; 402, nitrogen dioxide absorption device; 500, concentration device. DETAILED DESCRIPTION

[0026] The embodiments of the technical solutions of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used herein are only for the purpose of describing specific embodiments of the present application, and are not intended to limit the present application; the terms “include” and “have” and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0028] In the description of the embodiments of the present application, the technical terms “first”, “second”, etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of “a plurality of” is two or more, unless otherwise specifically limited.

[0029] ​​Reference to“an embodiment” herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase“in an embodiment” in various places in the specification are not necessarily referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. As will be apparent to those of ordinary skill in the art, embodiments described herein can be combined with other embodiments in accordance with the application.

[0030] In the description of the embodiments of the application, the term“and / or” only means an association relationship of the associated objects, which can represent three relationships, for example, A and / or B, which can represent three cases of existence of A alone, existence of A and B simultaneously, and existence of B alone. In addition, the character“ / ” herein generally represents an“or” relationship between the front and rear associated objects.

[0031] In the description of the embodiments of the application, the term“a plurality of” refers to two or more (including two), and similarly, “a plurality of groups” refers to two or more groups (including two groups), and “a plurality of pieces” refers to two or more pieces (including two pieces).

[0032] In the description of the embodiments of the application, the technical terms“center”,“longitudinal”,“transverse”,“length”,“width”,“thickness”,“upper”,“lower”,“front”,“rear”,“left”,“right”,“vertical”,“horizontal”,“top”,“bottom”,“inner”,“outer”,“clockwise”,“counterclockwise”,“axial”,“radial”,“circumferential”, and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the application.

[0033] In the description of the embodiments of the application, unless otherwise explicitly specified and limited, the technical terms“mounting”,“connection”,“connection”,“fixing”, and the like should be understood broadly, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the application can be understood according to the specific circumstances.

[0034] In the chemical production process, such as the production of coal-based conversion of phenolic compounds, phosphoric acid is widely used due to its strong specificity and good removal effect in removing basic nitrides of phenolic compounds in phenolic compounds. However, a large amount of high-concentration organic phosphoric acid waste liquid containing phenolic compounds is also produced. The inventors of the present application have noticed that at present, the neutralization method is a common treatment method for such organic phosphoric acid waste liquid. However, the neutralization method has many disadvantages, which will produce a large amount of solid waste, thereby causing secondary pollution problems; at the same time, the method cannot effectively degrade the organic matter in the waste phosphoric acid, which is not conducive to resource recycling and environmental protection. In addition, some existing treatment processes often need to be carried out under high temperature conditions, which not only has high energy cost, but also has complex equipment requirements, high treatment cost, and it is difficult to realize efficient treatment and resource recycling of the organic phosphoric acid waste liquid containing phenol.

[0035] In view of the above problems, the embodiments of the present application provide a recovery treatment method and system for organic phosphoric acid waste liquid containing phenol, which can efficiently recover phenolic organic matter and high-purity phosphoric acid from the phosphoric acid waste liquid, reduce the treatment cost, and realize resource recycling.

[0036] In the first aspect, referring to Figure 1 The embodiments of the present application provide a recovery treatment method for organic phosphoric acid waste liquid containing phenol, comprising:

[0037] S100: mixing the organic phosphoric acid waste liquid containing phenol to be treated with an extractant for extraction treatment to obtain an extraction phase and a raffinate phase, the raffinate phase containing nitrogen-containing organic cations and phosphate;

[0038] S200: treating the extraction phase to obtain phenolic compounds;

[0039] S300: using an oxidizing agent to oxidize the raffinate phase to degrade the nitrogen-containing organic cations, to obtain a gas phase component and a liquid phase component;

[0040] S400: collecting the liquid phase component to obtain reusable phosphoric acid.

[0041] In the S100 step, the organic phosphoric acid waste liquid containing phenol to be treated is mixed with an extractant for extraction treatment, the extractant can selectively combine with phenolic compounds, so as to separate the phenolic compounds from the organic phosphoric acid waste liquid containing phenol, into the extraction phase, and realize the preliminary separation of phenolic compounds and other components.

[0042] In the embodiments of the present application, the extractant needs to have high selectivity to phenolic compounds, and the extractant and phenolic compounds can be combined through specific intermolecular forces. For example, the extractant containing polar groups can produce strong binding force with the hydroxyl group of phenolic compounds through hydrogen bond, dipole-dipole interaction, etc., and has weak force with other components in the phosphoric acid waste liquid such as inorganic acid root.

[0043] In some embodiments, the extractant comprises one or more of alkane compounds, aromatic compounds, ether compounds, ester compounds and ketone compounds.

[0044] In the extraction process, the alkane can be used as a diluent to adjust the physical properties of the extraction system, reduce the viscosity of the system, and promote the mixing and mass transfer of the two phases; the aromatic compound contains a benzene ring structure and has a certain electron cloud density and polarity. Its π-π conjugated system can produce π-π interaction with the benzene ring of the phenol, and there may be weak hydrogen bond interaction or van der Waals force between the hydrogen atoms on the benzene ring and the phenolic hydroxyl group, so that the aromatic compound has a certain affinity for the phenol; the ether compound contains an ether bond in the molecule, and the lone pair electrons on the oxygen atom make it have a certain polarity, which can form a hydrogen bond with the hydroxyl group of the phenol, and promote the transfer of the phenol from the phenolic organic phosphoric acid waste liquid to the ether phase; the ester compound contains an ester group, and the carbonyl oxygen atom has strong electronegativity, which can form a hydrogen bond or a dipole-dipole interaction with the hydroxyl group of the phenol, and can rely on the intermolecular force with the phenol to extract the phenol into the organic phase.

[0045] Exemplarily, the alkane compound can be heptane; the aromatic compound can be toluene and / or dimethylbenzene; the ether compound can be diisopropyl ether and / or methyl tert-amyl ether; the ester compound can be butyl acetate and / or dimethyl carbonate; and the ketone compound can be methyl propyl ketone and / or methyl isopropyl ketone.

[0046] When the extractant is two or more of the above specific choices, the embodiments of the present application do not have any special limitation on the ratio of the above specific substances, and any ratio can be mixed.

[0047] In addition, since the extraction process in the embodiments of the present application can be carried out at a high temperature, the extractant is preferably an extractant with a boiling point of 60 o C o C. At the same time, the boiling point of the extractant is in the above moderate range, which is convenient for subsequent agent removal treatment.

[0048] Exemplarily, the boiling point of the extractant can be 60 o C, 65 o C, 70 o C, 75 o C, 80 o C, 85 o C, 90 o C, 95 o C, 100 o C, 105 o C, 110 o C, 115 o C, 120 o C or an interval range composed of any two of the above values.

[0049] In some embodiments, referring to Figure 2 mixing the phenol-containing organic phosphoric acid waste liquid to be treated with an extractant to obtain an extraction phase and a raffinate phase includes the following sub-steps:

[0050] S101: mixing the phenol-containing organic phosphoric acid waste liquid with an extractant to obtain a mixed liquid under a temperature condition of 50-100°C;

[0051] S102: stirring the mixed liquid for a first preset time, and separating the extraction phase and the raffinate phase after standing and layering.

[0052] In the embodiments of the present application, the phenol-containing organic phosphoric acid waste liquid is mixed with an extractant to obtain a mixed liquid under a temperature condition of 50-100°C. From the perspective of molecular motion, increasing the temperature can increase the rate of molecular thermal motion, so that the collision frequency between the molecules of the phenol-containing organic phosphoric acid waste liquid and the extractant increases, thereby accelerating the mass transfer process of the phenolic compounds from the waste liquid phase to the extractant phase. At a lower temperature, the molecular motion is slow, the mass transfer efficiency is low, and the extraction of phenols is insufficient; while at a too high temperature, on the one hand, it may cause an increase in the volatilization loss of the extractant, resulting in an increase in cost and environmental pollution.

[0053] The treatment method in the embodiments of the present application can especially cope with the case of high phosphoric acid content. When the phosphoric acid concentration is high, the viscosity of the waste liquid is large, and by mixing the phenol-containing organic phosphoric acid waste liquid with an extractant under a temperature condition of 50-100°C, a high mass transfer efficiency can be achieved.

[0054] Exemplarily, the temperature of mixing the phenol-containing organic phosphoric acid waste liquid with an extractant to obtain a mixed liquid is 50 o C, 55 o C, 60 o C, 65 o C, 70 o C, 75 o C, 80 o C, 85 o C, 90 o C, 95 o C, 100 o C or an interval range composed of any two of the above values.

[0055] The mixture is stirred for a first preset time, and after standing and layering, the extraction phase and the raffinate phase are separated. The stirring operation can increase the contact area of the two phases and strengthen the mass transfer process. Through stirring, the phenol-containing organic phosphoric acid waste liquid and the extractant can be more fully mixed, so that the phenolic compounds have more opportunities to contact and combine with the extractant molecules. Too high stirring intensity and too long time may cause emulsification, making it difficult to separate the two phases; insufficient stirring and too short time cannot achieve effective mass transfer. According to experimental verification, under suitable stirring conditions, the first preset time in the embodiments of the present application can be 20-40 min, which can make the phenolic compounds fully distribute in the two phases.

[0056] Exemplarily, the first preset time can be 20 min, 22 min, 24 min, 25 min, 26 min, 28 min, 30 min, 32 min, 34 min, 35 min, 36 min, 38 min, 40 min, or a range formed by any two of the above values.

[0057] The standing and layering process utilizes the density difference between the extraction phase and the raffinate phase to naturally separate the two phases. The standing time needs to be long enough to ensure that the two phases are completely layered, and exemplarily, the standing time is 20-40 min, thereby facilitating the subsequent effective separation of the two phases by liquid separation or the like.

[0058] The above-mentioned sub-steps of the extraction treatment are at least performed once. That is, after the last extraction treatment, the raffinate phase separated is subjected to extraction treatment with the extractant. For example, after the first extraction treatment, the extraction phase and the raffinate phase are obtained, and the raffinate phase is mixed with the extractant to obtain a mixture under the temperature condition of 50-100°C; the mixture is stirred for a first preset time, and after standing and layering, the extraction phase and the raffinate phase are separated. Exemplarily, the sub-steps of the extraction treatment are at least performed 3 times.

[0059] The cycle operation can significantly improve the extraction rate of phenolic compounds. Since the single extraction process is limited by the distribution coefficient, it is difficult to completely extract the phenols in the waste liquid, and by the cycle operation, the raffinate phase can be extracted again, and the residual amount of phenols in the raffinate phase can be continuously reduced. In addition, multiple cycle extractions can make the entire extraction process more stable, reduce the influence of factors such as fluctuations in raw material composition on the extraction effect, and ensure the stability of the quality of the final product.

[0060] The phenol-containing organic phosphoric acid waste liquid contains a large amount of phosphoric acid and basic nitrogen compounds, including pyridine, aniline and other substances. In an acidic environment, the basic nitrogen compounds will be converted into nitrogen-containing organic cations. Therefore, the raffinate phase contains nitrogen-containing organic cations and phosphate.

[0061] It should be noted that the extraction temperature is lower than the boiling point of the extractant.

[0062] In some embodiments, the mass ratio of the phenol-containing organic phosphoric acid waste liquid to the extractant is (2-6): 1.

[0063] In order to transfer as many phenolic compounds as possible from the phenol-containing organic phosphoric acid waste liquid to the extraction phase, it is necessary to ensure that the extractant has sufficient amount to combine with the phenols. If the amount of extractant is insufficient, the phenols cannot be fully extracted, resulting in too high a residual amount of phenols in the raffinate phase, affecting the recovery efficiency of the phenols and the purity of the subsequent phosphoric acid reuse; while the relative excess of the extractant, although it can ensure a high extraction rate, will increase the use cost of the extractant and the energy consumption of the subsequent agent removal treatment, and at the same time may lead to an increase in the difficulty of processing the extraction phase.

[0064] The present application considers the extraction temperature, extraction time and other parameters comprehensively, so that the mass ratio of the phenol-containing organic phosphoric acid waste liquid to the extractant is (2-6): 1. Under the temperature condition of 50-100℃, the above suitable mass ratio can make the extractant and the phenols fully contact and complete the mass transfer process in a short stirring time; when combined with the extraction cycle operation, under this mass ratio, a good extraction effect can be achieved for each cycle, reducing the number of cycles and improving the overall processing efficiency.

[0065] Exemplarily, the mass ratio of the phenol-containing organic phosphoric acid waste liquid to the extractant is 2:1, 3:1, 4:1, 5:1 or 6:1.

[0066] The recovery treatment method in the present application can process the organic phosphoric acid waste liquid generated in the removal of basic nitrogen compounds in phenolic compounds, and the pH of the phenol-containing organic phosphoric acid waste liquid is generally less than 2. In some embodiments, the phenol-containing organic phosphoric acid waste liquid includes the following mass fractions of components: 2-4% of water, 8-10% of phenolic compounds, 12-14% of basic nitrogen compounds, and 74-78% of phosphate.

[0067] Exemplarily, the mass fraction of phosphate in the phenol-containing organic phosphoric acid waste liquid can be 74%, 75%, 76%, 77% or 78%.

[0068] Exemplarily, the mass fraction of basic nitrogen compounds in the phenol-containing organic phosphoric acid waste liquid can be 12%, 13% or 14%.

[0069] Exemplarily, the mass fraction of phenolic compounds in the phenol-containing organic phosphoric acid waste liquid can be 8%, 9% or 10%.

[0070] Exemplarily, the mass fraction of water in the phenol-containing organic phosphoric acid waste liquid can be 2%, 3% or 4%.

[0071] The recovery treatment method in the embodiments of the present application can realize recovery of phosphoric acid from high-concentration phosphoric acid waste liquid.

[0072] In step S200, the extraction phase is subjected to a stripping treatment to obtain the phenolic compound. The embodiments of the present application separate the extractant from the phenolic compound by subjecting the extraction phase to a stripping treatment through a suitable stripping process, which not only can efficiently recover the phenolic compound, but also can realize recycling of the extractant, thereby reducing the production cost.

[0073] Specifically, the stripping can be performed by using a distillation method based on the difference in boiling points between the extractant and the phenolic compound. The extractant with a lower boiling point in the extraction phase is preferentially vaporized by heating the extraction phase, and the vapor is condensed to obtain the recovered extractant, while the phenolic compound remains in the distillation device. For example, when the extractant is methyl isobutyl ketone (boiling point about 116℃), the extraction phase is heated to a temperature slightly higher than its boiling point (such as 120~130℃) under a suitable vacuum degree, the methyl isobutyl ketone is rapidly vaporized, and after cooling by a condenser, the liquid extractant can be collected, and the remaining substance is the phenolic compound.

[0074] In order to improve the separation effect, a rectifying method can be used to realize more efficient separation of the extractant and the phenolic compound through multiple gas-liquid mass transfer in the rectifying tower, thereby reducing the residual amount of the extractant in the phenolic compound.

[0075] Exemplarily, the distillation device can be a rectifying tower.

[0076] Exemplarily, the system pressure during rectification is 20~60kpa, the tower top temperature is 60℃~120℃, and the reflux ratio is 10:1.

[0077] The treatment method of the embodiments of the present application can also use an adsorption separation method for stripping. An adsorbent (such as activated carbon, molecular sieve, etc.) with high selective adsorption capacity for the extractant is selected, and the extraction phase is passed through the adsorption column. The extractant is adsorbed by the adsorbent, while the phenolic compound passes through smoothly, thereby realizing separation of the two. Subsequently, the adsorbent can be regenerated by heating, purging, etc. to recover the extractant.

[0078] In step S300, the raffinate phase is subjected to an oxidation treatment with an oxidizing agent to degrade the nitrogen-containing organic cation to obtain a gas phase component and a liquid phase component. In the oxidation process, the oxidizing agent chemically reacts with the nitrogen-containing organic cation to oxidize and degrade it, and converts it into a gas phase and a liquid phase, which can effectively remove the nitrogen-containing organic cation in the raffinate phase.

[0079] The nitrogen atom of the nitrogen-containing organic cation can form a chemical bond with other groups in the raffinate phase. The oxidation treatment is based on the principle of redox reaction, uses the strong oxidizing property of the oxidizing agent to destroy the chemical bonds of the nitrogen-containing organic cation, and causes the structure of the nitrogen-containing organic cation to break and recombine. During the oxidation treatment, the nitrogen-containing organic cation in the raffinate phase gradually degrades as the oxidizing agent is added and the reaction proceeds.

[0080] The strong oxidizing environment provided by the oxidizing agent can extract electrons from the nitrogen-containing organic cation, causing the valence of the nitrogen element to increase and promoting it to gradually degrade into small molecular substances. The oxidizing agent first reacts with active groups on the surface of the nitrogen-containing organic cation, causing the macromolecular structure to gradually fragment; then, these fragments are further oxidized, and chemical bonds such as carbon-nitrogen bonds and carbon-carbon bonds are continuously broken, generating carbon dioxide, nitrogen dioxide, water, and some small molecular organic acids and other substances. By performing subsequent filtration, evaporation and concentration, and other treatments on the liquid phase components, small molecular organic acids and other impurities can be removed, thereby obtaining high-purity reusable phosphoric acid.

[0081] By performing oxidation treatment on the raffinate phase, the nitrogen-containing organic cation can be removed, avoiding the generation of solid waste or secondary pollution during the treatment of waste phosphoric acid. This treatment method can achieve complete degradation of the nitrogen-containing organic cation, deeply purify the waste phosphoric acid, and provide a guarantee for the reuse of phosphoric acid. At the same time, the oxidation treatment process does not require complex equipment and harsh reaction conditions, and can be completed in a relatively mild operating environment, reducing equipment investment and operating costs. In addition, the gas phase components generated during the treatment process can be reasonably utilized or harmlessly treated, and the phosphoric acid in the liquid phase components is efficiently recovered, truly realizing the recycling of resources, and having significant economic and environmental benefits.

[0082] It can be understood that steps S200 and S300 do not have a strict sequence, i.e., steps S200 and S300 are both performed after S100, steps S200 and S300 can be executed simultaneously, step S200 can be executed before step S300, or after step S300.

[0083] In some embodiments, the step of mixing the raffinate phase with the oxidizing agent to obtain the gas phase components and the liquid phase components includes: introducing the oxidizing agent into the raffinate phase at a temperature of 120°C to 160°C, and the oxidation reaction continues for a second predetermined time.

[0084] The processing method of the embodiments of the present application can improve the oxidation efficiency under the condition of mixing oxidation at 120-160°C. Increasing the temperature can significantly increase the rate of molecular thermal motion, greatly increase the collision frequency of oxidant molecules and nitrogen-containing organic cation molecules in the raffinate phase, effectively increase the percentage of activated molecules in the reaction, thereby accelerating the oxidation reaction rate. Within the above temperature range, the oxidation reaction can achieve the expected degradation effect in a shorter time, greatly improving the processing efficiency. At lower temperatures, some stable chemical bonds are difficult to be effectively destroyed by the oxidant, resulting in incomplete degradation; at higher temperatures, on the one hand, excessive temperature can accelerate the decomposition of the oxidant, such as hydrogen peroxide which can quickly decompose into water and oxygen at this temperature, reducing the effective utilization rate of the oxidant and increasing the processing cost; on the other hand, high temperature can promote the decomposition or volatilization of phosphoric acid, causing the loss of phosphoric acid, and can also cause side reactions during the degradation of nitrogen-containing organic cations, generating nitrogen-containing byproducts that are difficult to handle, affecting the separation and utilization of subsequent gas and liquid components.

[0085] The oxidant can be introduced into the raffinate phase by common introduction methods including bubbling introduction, jetting introduction, etc. Bubbling introduction is to introduce the oxidant in the form of gas from the bottom of the container, so that the oxidant rises in the form of bubbles in the raffinate phase and fully contacts with the nitrogen-containing organic cations to react. This method can ensure uniform mixing of the oxidant and the raffinate phase, and the bubbles continuously rupture and update the interface during the rising process, increasing the mass transfer area and facilitating the oxidation reaction. Jetting introduction is to disperse the oxidant solution into the raffinate phase in the form of high-speed jetting by high pressure, forming fine droplets, greatly increasing the contact area of the two phases and strengthening the mass transfer and reaction process.

[0086] The second predetermined time for which the oxidation reaction lasts can be determined by considering various factors. When the concentration of nitrogen-containing organic cations is high, a longer reaction time is needed to ensure their complete degradation; if the nitrogen-containing organic cations have complex structures and high stability, more reaction time is also needed to break their chemical bonds. Secondly, the type and amount of the oxidant also affect the second predetermined time. For example, when using ozone with strong oxidation ability as the oxidant, the reaction rate is relatively fast and the required time can be short; when using hydrogen peroxide or other oxidants with relatively weak oxidation ability, the reaction time can be appropriately extended. Exemplarily, under the condition of 120-160°C, the second predetermined time is 2-3.5h.

[0087] In some embodiments, the oxidant includes one or more of hydrogen peroxide, hydrogen peroxide, oxygen, and ozone.

[0088] The active ingredient of hydrogen peroxide is hydrogen peroxide, which is a relatively mild green oxidant. The molecular structure of hydrogen peroxide contains a peroxide bond, which has strong oxidizing ability. The decomposition products of hydrogen peroxide are only water and oxygen, which will not introduce additional impurity ions, and have little effect on the subsequent recovery of phosphoric acid. Moreover, the oxidation process is relatively mild, and the reaction rate and progress can be easily controlled.

[0089] In some embodiments, the concentration of hydrogen peroxide is ≥ 25%.

[0090] When the concentration of hydrogen peroxide is ≥ 25%, the number of hydrogen peroxide molecules in a unit volume increases significantly, which can more quickly and more fully react with nitrogen-containing organic cations, attack their chemical bonds, and promote the rapid degradation of nitrogen-containing organic cations, greatly enhancing the overall oxidizing ability of the oxidation system.

[0091] During the oxidation reaction, free radicals are continuously consumed as the reaction proceeds. The number of free radicals produced by hydrogen peroxide with a lower concentration is limited at high temperatures, which is difficult to maintain the oxidation intensity in the later stage of the reaction, and is prone to lead to incomplete oxidation. However, hydrogen peroxide with a concentration of ≥ 25% can continuously and stably supply hydroxyl radicals throughout the reaction process, ensuring that the oxidation reaction has sufficient oxidizing ability in the initial stage and the later stage, effectively avoiding the premature stagnation of the reaction due to insufficient supply of free radicals, and maintaining the efficiency and continuity of the oxidation process.

[0092] Oxygen is widely available and low in cost, and can be directly introduced. As an oxidizing agent, oxygen will not introduce new chemicals. Oxygen can also be introduced in the form of liquid oxygen.

[0093] Ozone has extremely strong oxidizing ability and stronger oxidizing ability than oxygen, and the oxidation speed is very fast, which can completely oxidize nitrogen-containing organic cations in a short time, and is especially suitable for treating refractory nitrogen-containing organic compounds. Moreover, its decomposition product is oxygen, which will not cause secondary pollution.

[0094] In the embodiments of the present application, one or more oxidizing agents selected from hydrogen peroxide, hydrogen peroxide, oxygen and ozone can be combined for use.

[0095] In step S400, after the above treatment, the main component in the liquid phase is phosphoric acid. By collecting the liquid phase, phosphoric acid that can be reused in the production process can be obtained, realizing efficient recovery and utilization of phosphoric acid.

[0096] It can be understood that step S400 is executed after S300, and there is no strict order between step S200 and step S400. Step S200 and step S400 can be executed synchronously, step S200 can be executed before step S400, or step S200 can be executed after step S400.

[0097] In some embodiments, please refer to Figure 3The step of collecting the liquid phase component to obtain reusable phosphoric acid includes:

[0098] S401: collecting the liquid phase component;

[0099] S402: concentrating the liquid phase component to obtain reusable phosphoric acid.

[0100] After the oxidation treatment, the liquid phase component may contain water and a small amount of small molecular impurities in addition to the target product phosphoric acid. For example, when hydrogen peroxide is used as the oxidizing agent, water will remain in the liquid phase component. By removing the water to increase the concentration of phosphoric acid, the concentration can be achieved to meet the reusable standard. The removal of water not only reduces the volume and weight of phosphoric acid during subsequent storage, transportation and use, thereby reducing costs, but more importantly, as the water evaporates, some low-boiling-point small molecular impurities such as small molecular organic acids are also removed, thereby preliminarily improving the purity of phosphoric acid and laying a foundation for its reuse in chemical production.

[0101] To further improve the purity of phosphoric acid, the concentrated phosphoric acid solution can be subjected to cooling crystallization treatment. By controlling the cooling speed and temperature, phosphoric acid is crystallized and separated from the solution. During the crystallization process, most of the impurities remain in the mother liquor due to the different solubility characteristics of the impurities in the solution than that of phosphoric acid. The phosphoric acid crystals can also be subjected to recrystallization treatment. The phosphoric acid crystals are dissolved in a suitable amount of pure water, and then subjected to cooling crystallization again. This process can further remove the residual impurities in the crystals and improve the purity of the product. After recrystallization, a small amount of pure water or an organic solvent such as ethanol is used to wash the phosphoric acid crystals to remove the impurities adsorbed on the surface of the crystals. The amount of washing liquid and the number of washing times need to be controlled to avoid excessive dissolution and loss of phosphoric acid crystals.

[0102] In some embodiments, further comprising: absorbing and collecting the gas phase component, the gas phase component comprising carbon dioxide and nitrogen dioxide.

[0103] The gas phase component produced after the oxidation treatment of the raffinate phase contains gases such as carbon dioxide and nitrogen dioxide. If directly discharged, it not only causes resource waste, but also pollutes the environment, so it is of great significance to absorb and collect it.

[0104] By absorbing and collecting the gas phase component, on the one hand, harmful gas emissions can be reduced, and the green and environmental protection concept can be implemented; on the other hand, the collected gas can be used as a resource, for example, carbon dioxide can be used to prepare carbonated beverages, dry ice, carbonates, or as a chemical raw material to participate in organic synthesis reactions; the collected nitrogen dioxide can be further treated and converted into valuable chemicals such as nitric acid, thereby realizing the recycling of resources and improving the economic and environmental benefits of the entire treatment process.

[0105] In some embodiments, the step of absorbing the gas phase components includes: absorbing the gas phase components through multiple stages of clean water to obtain a first absorption liquid and residual gas; and absorbing the residual gas through multiple stages of alkali liquor to obtain a second absorption liquid.

[0106] The absorption of the gas phase components through multiple stages of clean water is mainly based on the difference in solubility of carbon dioxide and nitrogen dioxide in water and a partial chemical reaction. Carbon dioxide is slightly soluble in water, nitrogen dioxide is easily soluble in water and chemically reacts with water. Since the gas phase components also include oxidant O2, nitrogen dioxide generates nitric acid in the presence of oxygen, which provides a basis for the removal of nitrogen dioxide in the gas phase components.

[0107] In the gas absorption process, the gas phase components first enter the first stage of clean water absorption device, which can be in the form of a spray tower or a packed tower. Exemplarily, in the spray tower, clean water is sprayed from the top of the tower in the form of uniform droplets, and the gas phase components flow from bottom to top, so that the gas and liquid phases are in full contact, and the preliminary absorption of carbon dioxide and nitrogen dioxide is achieved. The gas after the first stage of absorption enters the next stage of clean water absorption device, and the above process is repeated. Exemplarily, 3-5 stages of clean water absorption devices are provided, and the clean water in each stage can be replaced periodically or recycled according to the absorption situation. As the absorption proceeds, the clean water gradually absorbs the nitrogen dioxide in the gas to form a first absorption liquid. When the concentration of nitric acid in the first absorption liquid reaches a certain level, it can be collected and processed for subsequent recovery or further processing of nitric acid. After multiple stages of clean water absorption, most of the nitrogen dioxide is absorbed and converted, and the residual gas is mainly carbon dioxide.

[0108] The residual gas is absorbed through multiple stages of alkali liquor, which utilizes the neutralization reaction between the alkali liquor and the acidic gas to achieve effective absorption and removal of carbon dioxide. Exemplarily, the alkali liquor is sodium hydroxide solution, which reacts with carbon dioxide. If carbon dioxide is excessive, it will further react to generate sodium bicarbonate.

[0109] In the gas absorption process, the residual gas enters the first stage of alkali liquor absorption device, which can also be in the form of a spray tower or a packed tower. The alkali liquor is sprayed from the top of the tower and fully contacts with the gas flowing from bottom to top to occur neutralization reaction. The gas after the first stage of absorption enters the subsequent multiple stages of alkali liquor absorption device in turn to further improve the absorption effect. Exemplarily, 2-3 stages of alkali liquor absorption devices are provided. After multiple stages of alkali liquor absorption, a second absorption liquid is obtained, which mainly contains substances such as sodium carbonate and sodium bicarbonate. The second absorption liquid can be further processed, for example, by evaporation crystallization to recover the salt substances therein, realizing resource recycling. After the absorption of the alkali liquor, the harmful components in the discharged gas are greatly reduced, basically reaching the environmental protection emission standard.

[0110] In summary, the recycling method of the embodiments of the present application discards the traditional neutralization method, avoids the generation of solid waste through extraction and oxidation treatment, effectively solves the problem of secondary pollution, and is more in line with environmental protection requirements. The use of oxidizing agents to oxidize and degrade nitrogen-containing organic cations in the raffinate phase can effectively remove organic matter from waste phosphoric acid, improving the treatment effect of waste phosphoric acid. The low-temperature process with an operating temperature of ≤120℃ significantly reduces energy consumption compared to high-temperature treatment processes, saving a large amount of energy costs. At the same time, the low-temperature condition has low requirements for equipment, and does not require complex equipment, further reducing equipment investment and maintenance costs. The present application can directly treat waste acid, simultaneously recover phenolic compounds and high-purity phosphoric acid, and achieve efficient recovery and utilization of useful components in waste phosphoric acid, converting waste into reusable resources, reducing treatment costs, improving resource utilization, and achieving a phenolic compound recovery rate of 99% or more, a phosphoric acid recovery purity of 94.65%, and direct recycling for production, with good economic and environmental benefits.

[0111] In a second aspect, referring to Figure 4 The present application provides a recycling system for phenol-containing organic phosphoric acid waste liquid, comprising: an extraction device 100 for receiving phenol-containing organic phosphoric acid waste liquid and an extractant, extracting phenolic compounds from the phenol-containing organic phosphoric acid waste liquid by the extractant, and separating to obtain an extraction phase and a raffinate phase; a separation device 200 connected to the extraction device 100 for receiving the extraction phase and performing desolventizing treatment on the extraction phase; an oxidation device 300 connected to the extraction device 100 for receiving the raffinate phase and an oxidizing agent for oxidation reaction; and a gas absorption device 400 connected to the oxidation device 300 for receiving and absorbing the gaseous components generated by the oxidation reaction.

[0112] In the present application, the extraction device 100 is used to receive phenol-containing organic phosphoric acid waste liquid and an extractant, and extract phenolic compounds from the phenol-containing organic phosphoric acid waste liquid by the extractant in the extraction device 100, and then separate to obtain an extraction phase and a raffinate phase. The extraction device 100 can include an extraction kettle, a stirring assembly, a temperature control assembly, and a feed and discharge pipeline. The extraction kettle is made of corrosion-resistant material to adapt to the strong corrosiveness of the phenol-containing organic phosphoric acid waste liquid. The material of the extraction kettle is stainless steel lined with polytetrafluoroethylene. The stirring assembly can be equipped with a speed-adjustable stirrer to achieve sufficient mixing of the phenol-containing organic phosphoric acid waste liquid and the extractant through the rotation of the paddle. The paddle type can be selected according to the actual treatment requirements, such as turbine type and paddle type. The temperature control assembly can control the extraction temperature, for example, the extraction temperature is in the range of 50℃-100℃. The feed pipeline is connected to the phenol-containing organic phosphoric acid waste liquid storage tank and the extractant storage tank, respectively, and the discharge pipeline is connected to the separation device 200 and the oxidation device 300, respectively. Flow control valves and pressure gauges can be installed on the pipelines to control the flow and pressure of the materials.

[0113] The phenolic organic phosphoric acid waste liquid and the extractant are fed into the extraction kettle through the feed pipeline according to the preset mass ratio. Under the action of the stirring assembly, the two phases are rapidly mixed, and the extractant extracts the phenols from the waste liquid. After the extraction is completed, the liquid is allowed to stand and separate, and the extract phase is sent to the separation device 200 through the discharge pipeline according to the density difference between the two phases, and the raffinate phase is transported to the oxidation device 300.

[0114] The separation device 200 is used to receive the extract phase and perform desolventization treatment on the extract phase. Exemplarily, the separation device 200 is a distillation column equipped with a heating assembly, a condensing assembly, a rectifying assembly and a material conveying pump. The distillation column is internally provided with multiple layers of trays or fillers to increase the gas-liquid mass transfer area. The rectifying system includes a reflux device and a fractionating head, which can realize separation according to the boiling point difference between the extractant and the phenolic compounds. The material conveying pump is used to convey the extract phase to the distillation column, and to convey the separated phenolic compounds and the recovered extractant to the corresponding storage tanks, respectively.

[0115] The oxidation device 300 is used to receive the raffinate phase and the oxidizing agent for oxidation reaction. Exemplarily, the oxidation device 300 includes an oxidation reaction kettle, an oxidizing agent adding system, a temperature control system and a gas discharge pipeline. The oxidation reaction kettle is also made of corrosion-resistant material and can withstand a high temperature environment of 120°C~160°C. The oxidizing agent adding system includes an oxidizing agent storage tank, a metering pump and a conveying pipeline, which can control the addition amount of the oxidizing agent. The stirring system is used to ensure that the oxidizing agent and the raffinate phase are fully mixed to improve the reaction rate. The temperature control system maintains the reaction temperature through electric heating or steam heating, and is equipped with a cooling device to prevent the temperature from being too high. The gas discharge pipeline is connected to the gas absorption device 400, which is used to convey the gas phase components generated by the oxidation reaction to the subsequent processing link.

[0116] After the raffinate phase enters the oxidation reaction kettle, the oxidizing agent is added through the adding system according to the set proportion. Under the temperature condition of 120°C~160°C, the oxidizing agent reacts with the nitrogen-containing organic cation in the raffinate phase. After the reaction is completed, the liquid phase components are discharged through the discharge pipeline and can be further processed to obtain reusable phosphoric acid; the gas phase components are conveyed to the gas absorption device 400 through the gas discharge pipeline.

[0117] The gas absorption device 400 comprises a carbon dioxide absorption device 401 and a nitrogen dioxide absorption device 402. The nitrogen dioxide absorption device 402 can be a multi-stage clean water absorption tower, and the carbon dioxide absorption device 401 can be a multi-stage alkali liquor absorption tower. The gas absorption device 400 can further comprise a circulating pump, an absorption liquid storage tank, a gas discharge pipeline and the like. Exemplarily, the clean water absorption tower and the alkali liquor absorption tower both adopt a spray tower or a packed tower structure, and are provided with a spraying device, a packing layer and a demister in the tower. The circulating pump is used to realize the recycling use of the absorption liquid, the absorption liquid storage tank stores clean water and alkali liquor respectively, and is provided with a liquid level control system and a supplementing device. The gas discharge pipeline is connected with the oxidation device 300 and a final gas discharge port, and is used to transport and discharge the treated gas.

[0118] In some embodiments, a concentration device 500 is further included, which is connected with the oxidation device 300 and used to receive the liquid phase component after the oxidation reaction and concentrate the liquid phase component.

[0119] The concentration device 500 is connected with the oxidation device 300, and the liquid phase component treated by the oxidation device 300 is directly transported to the concentration device 500 for concentration, so as to ensure the continuity of the treatment process. The concentrated phosphoric acid enters a subsequent possible refining link to further improve the purity of the phosphoric acid, and finally obtain high-quality reusable phosphoric acid.

[0120] In the phenolic organic phosphoric acid waste liquid recycling treatment system of the embodiments of the present application, the devices are closely connected and cooperatively operated. The extraction device realizes the preliminary separation of phenolic compounds, thereby reducing the burden of subsequent treatment; the separation device efficiently recovers phenolic compounds and extractants, thereby improving the resource utilization rate; the oxidation device deeply treats the raffinate phase to degrade nitrogen-containing organic cations; and the gas absorption device treats the gaseous components generated in the oxidation, thereby realizing zero discharge of pollutants. The entire system can efficiently treat the phenolic organic phosphoric acid waste liquid, synchronously recover phenolic organic matter and high-purity phosphoric acid, avoid secondary pollution, reduce the treatment cost, has significant economic and environmental benefits, and is suitable for large-scale industrial application.

[0121] Embodiments

[0122] The following examples more specifically describe the present disclosure, which are merely illustrative and not intended to limit the scope of the present disclosure, because various modifications and changes can be made within the scope of the present disclosure, which will be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages and ratios reported in the following examples are based on weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods, and can be directly used without further treatment, and the instruments used in the examples are commercially available.

[0123] Example 1

[0124] Extraction section: the organic phosphoric acid waste liquid containing phenol is introduced into an extraction device, an extractant is continuously added into the extraction device, and the extraction is stirred at 100℃ for 30 minutes; the extractant is methyl isobutyl ketone, the mass ratio of the organic phosphoric acid waste liquid to the extractant is 4:1; after standing and separating, an extraction phase and a raffinate phase are obtained, and the above operation steps are repeated 3 times; the organic phosphoric acid waste liquid containing phenol includes the following components with mass fractions: water 2.2%, phenolic compounds 8.8%, basic nitrogen compounds 12.2%, and phosphates 76.8%.

[0125] Separation section: the extraction phase is introduced into a separation device which is a distillation column; the system pressure of the rectifying column is 20-60kpa, the overhead temperature is 60-120℃, and the reflux ratio is 10:1.

[0126] Oxidation section: the raffinate phase is introduced into an oxidation device, and high-purity oxygen is introduced into the extraction device; the oxidation reaction temperature is 120-160℃, and the time is 3h.

[0127] Absorption section: the gas generated in the oxidation section is introduced into a gas absorption device which includes a nitrogen dioxide absorption device and a carbon dioxide absorption device; the nitrogen dioxide absorption device is composed of three clean water absorption towers in series, and the carbon dioxide absorption device is composed of three sodium hydroxide absorption towers in series.

[0128] Concentration section: the liquid phase component treated by the oxidation device is transported to a concentration device for concentration; the concentration device is a distillation column, the system pressure is 20-60kpa, the overhead temperature is 80-130℃, and the reflux ratio is 10:1.

[0129] 100 tons of waste acid produce more than 79 tons of concentrated acid, the phosphoric acid recovery purity is more than 95%, which can be directly recycled for production, and the phenolic compound recovery rate is more than 95%.

[0130] Example 2

[0131] The organic phosphoric acid waste liquid containing phenol is treated, and the treatment process is similar to that of Example 1, except that the extraction section is stirred at 60℃ for 40 minutes.

[0132] 100 tons of waste acid produce 79.35 tons of concentrated acid, the phosphoric acid recovery purity is 96.82%, which can be directly recycled for production, and the phenolic compound recovery rate is 96.5%.

[0133] Example 3

[0134] The organic phosphoric acid waste liquid containing phenol is treated, and the treatment process is similar to that of Example 1, except that the extractant in Example 1 is replaced by methyl tert-amyl ether in the extraction section.

[0135] 100 tons of waste acid output 79.16 tons of concentrated acid, the recovery of phosphoric acid purity 96.25%, can be directly recycled for production, phenolic compounds recovery rate of 97.8%.

[0136] Example 4

[0137] The phenolic organic phosphoric acid waste liquid is treated, and the treatment process is similar to that of Example 1, except that in the oxidation section, high-purity oxygen is replaced by 30% hydrogen peroxide, and high-purity oxygen is introduced into the extraction device, and the mass ratio of hydrogen peroxide to waste phosphoric acid is 2:1.

[0138] A concentration section is added after the absorption section, and the liquid phase component treated by the oxidation device is transported to the concentration device for concentration. The concentration device is a distillation column, the system pressure is 20~60kpa, the overhead temperature is 80-130℃, and the reflux ratio is 10:1.

[0139] 100 tons of waste acid output 79.76 tons of concentrated acid, the recovery of phosphoric acid purity 95.83%, can be directly recycled for production, phenolic compounds recovery rate of 98.2%.

[0140] Comparative Example 1

[0141] The phenolic organic phosphoric acid waste liquid is treated, and the treatment process is similar to that of Example 1, except that the extraction section is stirred at 25℃ for 30 minutes.

[0142] 100 tons of waste acid output 83.34 tons of concentrated acid, the recovery of phosphoric acid purity 91.65%, phenolic compounds recovery rate of 80.2%.

[0143] In Comparative Example 1, due to the low extraction temperature, the recovery rate of phenolic compounds is low, which ultimately leads to incomplete oxidation of the same amount of oxidizing agent, and the recovered phosphoric acid contains phenolic compounds and basic nitrogen compounds, which affects the purity of the treated sample when used in production, so it cannot be directly recycled for production.

[0144] Comparative Example 2

[0145] The phenolic organic phosphoric acid waste liquid is treated, and the treatment process is similar to that of Example 1, except that in the oxidation section, the oxidation reaction temperature is 80℃.

[0146] 100 tons of waste acid output 87.52 tons of concentrated acid, the recovery of phosphoric acid purity 85.26%, phenolic compounds recovery rate of 98.6%.

[0147] In Comparative Example 2, because the oxidation temperature is low, the oxidation level of the oxidizing agent is reduced, which cannot be completely oxidized, and the recovered phosphoric acid contains phenolic compounds and basic nitrogen compounds, which affects the purity of the treated sample when used in production, so it cannot be directly recycled for production.

[0148] In summary, the recovery treatment method and system of the phenol-containing organic phosphoric acid waste liquid in the embodiments of the present application can realize efficient resource recovery through the synergistic process of "selective separation of extractant phenol + oxidant oxidation degradation + purification of phosphoric acid", the recovery rate of phenolic compounds is more than 95%, the recovery purity of phosphoric acid is 95%, and the recovered phosphoric acid can be directly recycled for production; meanwhile, it is environmentally friendly and economical, the cost of hazardous waste treatment can be avoided, more than 79 tons of concentrated acid can be produced from 100 tons of waste phosphoric acid; the degradation rate of organic matter is 100%, secondary pollution is reduced; meanwhile, the operating temperature is relatively low at 100-160°C, the by-products after oxidation are all absorbed to produce nitric acid and carbonate products, and there is no other pollution.

[0149] The above is only a specific embodiment of the present application, and those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system, module and unit described above can refer to the corresponding process in the foregoing method embodiments, which will not be described herein. It should be understood that the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed in the present application, and these modifications or replacements should be covered within the protection scope of the present application.

Claims

1. A method for recovering and treating phenol-containing organophosphoric acid waste liquid, characterized in that, include: The phenol-containing organophosphoric acid waste liquid to be treated is mixed with an extractant and extracted to obtain an extract phase and a raffinate phase. The raffinate phase includes nitrogen-containing organic cations and phosphate ions. The phenol-containing organophosphoric acid waste liquid to be treated comprises the following components by mass fraction: water 2-4%, phenolic compounds 8-10%, basic nitrogen compounds 12-14%, and phosphate ions 74-78%. The extraction is carried out at a temperature of 50℃~100℃, and the mass ratio of the phenol-containing organophosphoric acid waste liquid to the extractant is (2~6):

1. The extract phase was subjected to a descaling treatment to obtain phenolic compounds; The raffinate phase is oxidized using an oxidant to degrade nitrogen-containing organic cations, yielding a gaseous component and a liquid component; this includes: introducing the oxidant into the raffinate phase at a temperature of 120℃~160℃, with the oxidation reaction lasting for a second preset time; the oxidant includes one or more of hydrogen peroxide, hydrogen peroxide, oxygen, and ozone; the concentration of hydrogen peroxide is ≥25%; The gaseous components, including carbon dioxide and nitrogen dioxide, are absorbed and collected. The liquid phase components are collected to obtain reusable phosphoric acid.

2. The method for recovering and treating phenol-containing organophosphoric acid waste liquid according to claim 1, characterized in that, The process of mixing the phenol-containing organophosphate waste liquid to be treated with an extractant for extraction to obtain the extract phase and raffinate phase includes the following sub-steps: The phenol-containing organophosphate waste liquid was mixed with an extractant at a temperature of 50℃~100℃ to obtain a mixed solution. The mixture is stirred for a first preset time, allowed to stand and separate into layers to obtain the extract phase and the raffinate phase. Each sub-step of the extraction process is repeated at least once.

3. The method for recovering and treating phenol-containing organophosphoric acid waste liquid according to claim 1 or 2, characterized in that, The extractant includes one or more of the following: alkanes, aromatics, ethers, esters, and ketones.

4. The method for recovering and treating phenol-containing organophosphoric acid waste liquid according to claim 1, characterized in that, The step of collecting the liquid phase component to obtain reusable phosphoric acid includes: Collect the liquid phase component; concentrate the liquid phase component to obtain reusable phosphoric acid.

5. The method for recovering and treating phenol-containing organophosphoric acid waste liquid according to claim 1, characterized in that, The steps for absorbing and collecting gaseous components include: absorbing the gaseous components through a multi-stage water bath to obtain a first absorbent and a residual gas; The remaining gas is absorbed by a multi-stage alkaline solution to obtain a second absorbent.

6. A system for recovering and treating phenol-containing organophosphoric acid waste liquid, used to implement the method for recovering and treating phenol-containing organophosphoric acid waste liquid according to any one of claims 1-5, characterized in that, include: An extraction device is used to receive phenol-containing organophosphoric acid waste liquid and an extractant, and to extract phenolic compounds from the phenol-containing organophosphoric acid waste liquid through the extractant, thereby separating the extract phase and the raffinate phase. A separation device, connected to the extraction device, is used to receive the extraction phase and perform desolventizing treatment on the extraction phase; An oxidation device, connected to the extraction device, is used to receive the raffinate and the oxidant for an oxidation reaction; A gas absorption device, connected to the oxidation device, is used to receive and absorb the gaseous components generated by the oxidation reaction.

7. The system for recovering and treating phenol-containing organophosphoric acid waste liquid according to claim 6, characterized in that, It also includes a concentration device, which is connected to the oxidation device, for receiving the liquid phase components after the oxidation reaction and concentrating the liquid phase components.

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