Method for efficiently recovering phosphorus and fluorine from byproduct defluorination residues in DCP (dicumyl peroxide) production

Abstract

The invention discloses a method for efficiently recovering phosphorus and fluorine from a byproduct defluorination residue in DCP (dicumyl peroxide) production, and belongs to the field of phosphorus and fluorine recovery. The method comprises the following steps: adjusting the proportioning of process water and defluorination residue dry powder through a solid content detector to obtain a slurry mixed solution with the solid content of 20-30%; pumping the slurry mixed solution into a reaction kettle, adding sulfuric acid into the reaction kettle according to the mass ratio of the sulfuric acid addition amount to the slurry mixed solution of (0.08-0.1): 1, and mixing to obtain a sulfuric acid slurry mixture; keeping the reaction temperature of the sulfuric acid slurry mixture in the reaction kettle at 75-80 DEG C, and keeping the reaction time for 4-5 hours to obtain acidolysis slurry; the acidolysis slurry is conveyed to a plate and frame filter for solid-liquid separation, and phosphorus and fluorine liquid-phase recovery liquid and solid-phase residues are obtained; judging whether the solid-phase residues meet the water-soluble phosphorus content gt or not; 0.86% or the fluoride content gt; 1.36% of one or more than one; if yes, phosphorus and fluorine recovery operation is executed again on the solid-phase residues.

Description

Technical Field

[0001] This application relates to the field of phosphorus and fluorine recovery, and in particular to a highly efficient method for recovering phosphorus and fluorine from defluorination residue, a byproduct of DCP production. Background Technology

[0002] The production process of DCP (dihydrocalcium phosphate) generates a large amount of defluorination residue, which is rich in phosphorus and fluorine. If not handled properly, it will not only waste resources but may also cause environmental problems.

[0003] Currently, existing technologies for treating defluorination residues mostly employ acid leaching processes. This involves adding sulfuric acid to the defluorination residues and then simply stirring to induce an acidolysis reaction between the sulfuric acid and the phosphates and fluorides in the residues. This produces soluble phosphoric acid and fluorides that enter the liquid phase, thereby achieving the separation of phosphorus and fluorine elements from the residues.

[0004] However, in the acid leaching process of defluorination residue, simple stirring methods can easily lead to insufficient separation of phosphorus and fluorine elements, resulting in unstable phosphorus and fluorine recovery efficiency and failing to guarantee the resource recovery effect. Furthermore, if the residue generated after separation is not properly treated, it may also have adverse effects on the environment. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a highly efficient method for recovering phosphorus and fluorine from the defluorination residue of DCP production byproducts, the method comprising: By adjusting the proportions of process water and defluorinated residue dry powder using a solids content analyzer, a slurry mixture with a solids content of 20% to 30% was obtained. The slurry mixture is pumped into the reactor, and then sulfuric acid is added to the reactor at a mass ratio of sulfuric acid to the slurry mixture of 0.08~0.1:1 to obtain a sulfuric acid slurry mixture. The sulfuric acid slurry mixture is kept at a reaction temperature of 75-80°C in the reactor for 4-5 hours to obtain an acid hydrolysis slurry. The acid hydrolysis slurry is fed to a plate and frame filter press for solid-liquid separation to obtain a phosphorus and fluorine liquid phase recovery liquid and solid residue. Determine whether the solid residue meets one or more of the following conditions: water-soluble phosphorus content > 0.86% or fluoride content > 1.36%; If so, the phosphorus and fluorine recovery operation is repeated on the solid residue.

[0006] Optionally, the phosphorus content of the phosphorus-fluoride liquid phase recovery solution is 46214~126735 mg / L, and the fluoride content is 2755~23540 mg / L.

[0007] Optionally, after conveying the acid hydrolysis slurry to a plate and frame filter press for solid-liquid separation to obtain a phosphorus and fluorine liquid recovery liquid and solid residue, the method further includes: Determine whether the phosphorus and fluorine liquid phase recovery solution meets the requirements of phosphorus recovery rate ≥ 60% and fluorine recovery rate ≥ 70%; If so, maintain the current sulfuric acid addition amount, the reaction temperature in the reactor, and the reaction time, and recycle the phosphorus and fluorine liquid phase recovery solution that meets the phosphorus and fluorine recovery rate.

[0008] Optionally, after determining whether the phosphorus and fluorine liquid phase recovery solution meets the requirements of phosphorus recovery rate ≥ 60% and fluorine recovery rate ≥ 70%, the method further includes: If not, one or more of the following should be adjusted: the amount of sulfuric acid added, the reaction temperature, or the reaction time. The phosphorus and fluorine liquid phase recovery solution that does not meet the phosphorus and fluorine recovery rate should be recycled.

[0009] Optionally, adjusting the amount of sulfuric acid added includes: The amount of sulfuric acid added is increased within the range of 0.08 to 0.1:1 (mass ratio of sulfuric acid added to slurry mixture).

[0010] Optionally, adjusting the reaction time in the reactor includes: The reaction time in the reactor is extended within the range of 4 to 5 hours.

[0011] Optionally, adjusting the reaction temperature of the reactor includes: The temperature inside the reactor is increased within the reaction temperature range of 75~80℃.

[0012] Optionally, the step of adjusting the proportions of process water and defluorination residue dry powder using a solids content analyzer to obtain a slurry mixture with a solids content of 20% to 30% includes: Add defluorinated residue dry powder and process water to the mixing tank, and start the mixing tank to stir, to obtain a preliminary mixed slurry; The solid content of the preliminary mixed slurry was monitored using a solid content analyzer to obtain slurry solid content data; According to the solid content data of the slurry, the process water or the defluorination residue dry powder is added to the preliminary mixed slurry, and the stirring of the mixing tank is maintained to obtain a slurry mixture with a solid content of 20%~30%.

[0013] Optionally, after determining whether the solid residue meets one or more of the following conditions: water-soluble phosphorus content > 0.86% or fluoride content > 1.36%, the method further includes: If not, the solid residue will be collected and disposed of as harmless waste.

[0014] Optionally, the process water has a phosphorus content of 0.03 mg / L and a fluoride content of 0.06 mg / L.

[0015] As can be seen from the above technical solutions, this application has the following beneficial effects: This application utilizes a solids content analyzer to strictly control the solids content of the slurry mixture at 20%~30%, ensuring good fluidity for sufficient contact between the slurry and sulfuric acid, while effectively preventing incomplete reactions due to excessively high or low solids content. It also prevents equipment blockage during transport, thus guaranteeing the entire phosphorus and fluorine recovery process. Next, by maintaining a sulfuric acid to slurry ratio of 0.08~0.1:1, the application ensures sufficient reaction between sulfuric acid and phosphorus and fluorine in the slurry, effectively avoiding reagent waste and increased wastewater treatment load caused by excessive sulfuric acid. Then, by maintaining the sulfuric acid slurry mixture at a reaction temperature of 75~80℃ and a reaction time of 4~5 hours in the reactor, the application ensures complete acidolysis and effectively improves the separation efficiency of phosphorus and fluorine, reducing fluctuations in recovery efficiency. Finally, a plate and frame filter press is used for solid-liquid separation, further enhancing the separation effect between the liquid and solid phases. Finally, by detecting the phosphorus and fluorine content of solid residues, it is possible to identify solid residues that do not meet the standards in a timely manner, and to recycle these substandard residues. This not only minimizes the waste of phosphorus and fluorine resources, but also reduces the environmental risks that may be caused by the direct disposal of solid residues, thus achieving a dual guarantee of resource recycling and environmental protection requirements. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A flowchart illustrating an embodiment of the efficient method for recovering phosphorus and fluorine from the defluorination residue of DCP production by-products provided in this application; Figure 2 Flowchart of another embodiment of the efficient method for recovering phosphorus and fluorine from the defluorination residue of DCP production by-products provided in this application; Figure 3 This is a flowchart of another embodiment of the efficient method for recovering phosphorus and fluorine from the defluorination residue of DCP production by-product provided in this application. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described examples are only one embodiment of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Please see Figure 1 This application first provides an embodiment of an efficient method for recovering phosphorus and fluorine from the defluorination residue, a byproduct of DCP production, which includes: S101. Adjust the proportions of process water and defluorinated residue dry powder using a solids content analyzer to obtain a slurry mixture with a solids content of 20%~30%. In this embodiment, the solids content analyzer is placed in the mixing tank and is used to determine the mass percentage of solid particles in the mixture within the tank. The process water is industrial water with a phosphorus content of 0.03 mg / L and a fluoride content of 0.06 mg / L. The defluorination residue powder is a byproduct generated during the production of DCP dicalcium phosphate, rich in phosphorus and fluorine, and has extremely high recycling value.

[0020] Before obtaining the slurry mixture, the defluorination residue dry powder and process water are first added to the mixing tank, and the mixing components are started to form a preliminary slurry. At the same time, the solid content detector will collect the mass percentage data of the solid components in the slurry in real time during the mixing process. If the solid content is less than 20%, it means that the slurry is too thin and the defluorination residue dry powder needs to be added to increase the solid content. If the solid content is more than 30%, it means that the slurry is too thick and the process water needs to be added to reduce the solid content and prevent subsequent conveying blockage. Finally, through the closed-loop control of "monitoring-feeding-mixing", a slurry mixture with a solid content of 20% to 30% can be obtained.

[0021] S102. Pump the slurry mixture into the reactor, and then add sulfuric acid into the reactor according to the mass ratio of sulfuric acid to slurry mixture of 0.08~0.1:1 to obtain sulfuric acid slurry mixture; In this embodiment, the reactor is a closed container used for acidolysis, equipped with stirring and temperature control functions to ensure that the sulfuric acid and slurry mixture react in a stable environment. The sulfuric acid slurry mixture is the reactant formed by mixing the slurry mixture and sulfuric acid in a specific ratio.

[0022] Before obtaining the sulfuric acid slurry mixture, the slurry mixture in the mixing tank needs to be transported to the reactor by a transfer pump. Then, the required amount of sulfuric acid to be added is calculated based on the mass of the slurry mixture input into the reactor. For example, 8-10 kg of sulfuric acid should be added for 100 kg of slurry mixture. Subsequently, the sulfuric acid is slowly added to the slurry mixture along the inner wall of the reactor through the sulfuric acid metering and adding device set on the reactor. Then, the reactor is started to stir, so that the sulfuric acid and the slurry mixture can be initially mixed to form a sulfuric acid slurry mixture.

[0023] S103. The sulfuric acid slurry mixture is kept at a reaction temperature of 75~80℃ in a reactor and the reaction time is kept at 4~5 hours to obtain acid hydrolysis slurry; In this embodiment, before obtaining the acid hydrolysis slurry, the temperature inside the reactor containing the sulfuric acid slurry mixture needs to be set within the range of 75~80°C and maintained for 4~5 hours to allow the sulfuric acid to fully react with the phosphorus and fluorine compounds in the slurry, ultimately obtaining an acid hydrolysis slurry containing soluble phosphorus and fluorine components.

[0024] S104. The acid hydrolysis slurry is fed to a plate and frame filter press for solid-liquid separation to obtain phosphorus and fluorine liquid phase recovery liquid and solid phase residue. In this embodiment, the plate and frame filter press is a device that achieves solid-liquid separation through pressure and filter cloth retention. The filtrate of the phosphorus and fluoride liquid phase recovery solution is pale yellow, with a soluble phosphorus content of 46214-126735 mg / L and a fluoride content of 2755-23540 mg / L. The solid residue is the solid component retained by the filter cloth after filtration by the plate and frame filter press, containing unreacted water-soluble phosphorus and fluoride compounds.

[0025] Before solid-liquid separation of the acid hydrolysis slurry, a delivery pump first transports the slurry to the filter chamber of a plate and frame filter press, which consists of filter plates and filter cloth. Next, the plate and frame filter press activates its internal hydraulic components to push the filter plates together, creating a stable pressure difference of 0.3~0.6 MPa. Then, driven by this pressure difference, soluble phosphorus and fluoride in the acid hydrolysis slurry pass through the filter cloth and collect in a collection tank, forming a phosphorus and fluoride liquid phase recovery liquid. Subsequently, unreacted solids, calcium sulfate, and other solid components are trapped by the filter cloth, and after continuous compression, they accumulate into clumps, forming solid residue.

[0026] S105. Determine whether the solid residue meets one or more of the following conditions: water-soluble phosphorus content > 0.86% or fluoride content > 1.36%; In this embodiment, after obtaining the solid residue, the water-soluble phosphorus and fluoride components in the residue are first extracted with deionized water. Then, the concentration values ​​of the corresponding components are read using a chemical analysis instrument and converted into mass percentages. The concentration values ​​are then compared with the water-soluble phosphorus content > 0.86% or the fluoride content > 1.36%, and it is determined whether the phosphorus and fluoride in the solid residue meet one or more of the following conditions: water-soluble phosphorus content > 0.86% or fluoride content > 1.36%. If one or more of the following conditions are met, it indicates that the solid residue still contains recyclable resources, and step S106 needs to be executed. If neither condition is met, it indicates that the solid residue is harmless waste residue, and step S107 needs to be executed.

[0027] S106. Perform phosphorus and fluorine recovery operation again on the solid residue.

[0028] In this embodiment, when the phosphorus and fluorine content of the solid residue is confirmed to meet one or more of the preset standards of water-soluble phosphorus content > 0.86% or fluoride content > 1.36%, it indicates that there are unreacted phosphates, fluorides, and other recyclable resources in the solid residue. At this point, the solid residue needs to be transported back to the mixing tank and mixed with process water, undergoing the "slurry preparation - sulfuric acid and slurry mixing - acid hydrolysis heating reaction - solid-liquid separation - phosphorus and fluorine content detection" process again to complete the phosphorus and fluorine recovery operation.

[0029] S107. Solid residues shall be collected and disposed of as harmless waste residues.

[0030] In this embodiment, when it is confirmed that the phosphorus and fluorine content of the solid residue does not meet one or more of the preset standards of water-soluble phosphorus content > 0.86% or fluoride content > 1.36%, it indicates that the recoverable phosphorus and fluorine resources in the solid residue have been basically extracted, and the residual phosphorus and fluorine components will not cause water or soil pollution due to rainwater leaching, soil contact, etc., and are therefore considered harmless waste residue. At this time, it is necessary to collect the harmless waste residue in a unified manner, transport it to a compliant industrial landfill in sealed containers, or further process it for resource utilization as building auxiliary materials, thus avoiding the environmental problems that may be caused by the random dumping of waste residue.

[0031] This embodiment utilizes a solids content analyzer to strictly control the solids content of the slurry mixture at 20%~30%. This ensures good fluidity of the slurry mixture, guaranteeing sufficient contact between the sulfuric acid and the mixture, and effectively avoids incomplete reactions caused by excessively high or low solids content. It also prevents equipment blockage during transport, thus ensuring the success of the entire phosphorus and fluorine recovery process. Next, by maintaining a sulfuric acid to slurry mixture ratio of 0.08~0.1:1, the ratio of sulfuric acid to phosphorus and fluorine in the mixture is ensured to react fully while effectively avoiding reagent waste and increased wastewater treatment load due to excessive sulfuric acid. Then, by maintaining the sulfuric acid slurry mixture at a reaction temperature of 75~80℃ and a reaction time of 4~5 hours in the reactor, the acidolysis reaction is ensured to be complete, effectively improving the separation efficiency of phosphorus and fluorine and reducing fluctuations in recovery efficiency. Furthermore, a plate and frame filter press is used for solid-liquid separation, further enhancing the separation effect between the liquid and solid phases. Finally, by detecting the phosphorus and fluorine content of solid residues, it is possible to identify solid residues that do not meet the standards in a timely manner, and to recycle these substandard residues. This not only minimizes the waste of phosphorus and fluorine resources, but also reduces the environmental risks that may be caused by the direct disposal of solid residues, thus achieving a dual guarantee of resource recycling and environmental protection requirements.

[0032] Please see Figure 2 This application first provides an embodiment of another efficient method for recovering phosphorus and fluorine from the defluorination residue, a byproduct of DCP production, which includes: S201. Determine whether the phosphorus and fluorine liquid phase recovery solution meets the requirements of phosphorus recovery rate ≥60% and fluorine recovery rate ≥70%; In this embodiment, the phosphorus recovery rate is the percentage of phosphorus in the phosphorus-fluorine liquid phase recovery liquid relative to the total phosphorus in the defluorination residue dry powder, with a standard of ≥60%, reflecting the effective transfer efficiency of phosphorus from solid residue to the liquid phase. The fluorine recovery rate is the percentage of fluorine in the phosphorus-fluorine liquid phase recovery liquid relative to the total fluorine in the defluorination residue dry powder, with a standard of ≥70%, reflecting the effective transfer efficiency of fluorine from solid residue to the liquid phase.

[0033] After obtaining the phosphorus and fluorine liquid phase recovery solution, the actual phosphorus and fluorine contents in the solution need to be determined using a chemical analysis instrument. Then, based on the total phosphorus and fluorine content in the defluorination residue dry powder, the actual phosphorus recovery rate and fluorine recovery rate are calculated. Further, the actual phosphorus and fluorine recovery rates are compared with the pre-set standard of phosphorus recovery rate ≥60% and fluorine recovery rate ≥70% to determine whether the liquid phase recovery solution simultaneously meets both indicators. If both indicators are met, step S202 is executed; otherwise, step S203 is executed.

[0034] S202. Maintain the current sulfuric acid addition amount, reaction temperature and reaction time in the reactor, and recycle the phosphorus and fluorine liquid phase recovery liquid that meets the phosphorus and fluorine recovery rate. In this embodiment, when the phosphorus and fluorine liquid phase recovery liquid meets the preset standards of phosphorus recovery rate ≥60% and fluorine recovery rate ≥70%, it indicates that the current sulfuric acid addition, reaction temperature, and reaction time in the reactor are perfectly matched with the acidolysis reaction, which can promote the conversion of phosphorus and fluorine from dry powder residue into soluble liquid phase components without the need to adjust the relevant parameters in the reactor. Simultaneously, the qualified phosphorus and fluorine liquid phase recovery liquid needs to be introduced into the purification and refining stage, where it is converted into phosphate and fluoride products through processes such as impurity removal and concentration, achieving full recovery of phosphorus and fluorine resources.

[0035] S203. Adjust one or more of the following: sulfuric acid addition amount, reaction temperature, or reaction time, and recover the phosphorus and fluorine liquid phase recovery liquid that does not meet the phosphorus and fluorine recovery rate.

[0036] In this embodiment, when the phosphorus and fluorine liquid phase recovery solution does not meet the preset standards of phosphorus recovery rate ≥60% and fluorine recovery rate ≥70%, it indicates that there is a deviation in the process parameters of the current batch, such as the amount of sulfuric acid added, reaction temperature, or reaction time, which has room for optimization. At this time, the result will be recorded and parameters will be optimized to provide more optimized reaction conditions for the next batch of materials. One or more of the following parameters can be adjusted specifically: Optionally, the amount of sulfuric acid added can be increased within the range of 0.08 to 0.1:1 (mass ratio of sulfuric acid to slurry mixture). If the low recovery rate of the current batch is determined to be due to insufficient sulfuric acid, the amount of sulfuric acid added should be increased when processing the next batch. For example, if the current batch, with a mass ratio of 0.08:1, shows a phosphorus recovery rate of <55% or a fluorine recovery rate of <65%, the mass ratio for the next batch can be set to 0.09:1. By supplementing the reaction of the new batch with sufficient hydrogen ions, the complete conversion of phosphorus and fluorine compounds can be promoted.

[0037] Optionally, the reaction time of the reactor can be extended within the range of 4 to 5 hours; If insufficient reaction time in the current batch is determined to be the main cause of incomplete conversion, the reaction time for the next batch needs to be extended. For example, if the phosphorus recovery rate is <58% or the fluorine recovery rate is <68% after 4 hours of reaction in the current batch, the reaction time for the next batch can be set to 4.5 hours to provide a more sufficient period for the reaction of the new feedstock.

[0038] Optionally, the temperature inside the reactor can be increased within the reaction temperature range of 75~80℃; If the current batch exhibits slow kinetics due to a low reaction temperature, the reaction temperature for the next batch should be increased. For example, if the fluorine recovery rate is <66% or the phosphorus recovery rate is <56% after the current batch reacts at 75°C, the reaction temperature for the next batch can be set to 76°C to provide a more sufficient reaction temperature for the new batch.

[0039] The above parameters can be adjusted according to actual conditions, and no specific restrictions are imposed here. Next, after the parameters are adjusted and set, the stirring, acidification, and heating operations for the next batch of materials can begin using these new parameters, aiming to improve and stabilize the phosphorus and fluorine recovery rate within the predetermined target range. Simultaneously, the phosphorus and fluorine liquid phase recovery liquid from the current batch that does not meet the phosphorus and fluorine recovery rate will be recycled, maximizing the utilization of residual phosphorus and fluorine substances in the liquid phase recovery liquid through purification and refining.

[0040] This embodiment clarifies whether the phosphorus and fluorine liquid-phase recovery solution meets the standard of phosphorus recovery rate ≥60% and fluorine recovery rate ≥70%, providing a basis for subsequent adjustments to the sulfuric acid addition, reaction temperature, and reaction time within the reactor. When the set phosphorus and fluorine recovery rates are met, maintaining the current sulfuric acid addition, reaction temperature, and reaction time ensures the stability of subsequent batches of phosphorus and fluorine recovery. Furthermore, directly recovering resources from the qualified recovery solution fully utilizes the effective components and reduces resource waste. When the set phosphorus and fluorine recovery rates are not met, at least one of the sulfuric acid addition, reaction temperature, or reaction time can be adjusted promptly to quickly optimize reaction conditions, improve the phosphorus and fluorine recovery rate of subsequent batches, and make the recovery process more flexible and adaptable. Moreover, regardless of whether the phosphorus and fluorine recovery rate meets the standard, the phosphorus and fluorine liquid-phase recovery solution is always recycled, avoiding resource waste, maximizing the value of the phosphorus and fluorine liquid-phase recovery solution, and achieving efficient resource recycling and maximizing economic benefits.

[0041] Please see Figure 3 This application first provides an embodiment of another efficient method for recovering phosphorus and fluorine from the defluorination residue, a byproduct of DCP production, which includes: S301. Add defluorination residue dry powder and process water to the mixing tank, and start the mixing tank to stir to obtain a preliminary mixed slurry; In this embodiment, before obtaining the initial mixed slurry, it is necessary to simultaneously add defluorination residue dry powder and process water to the mixing tank. Then, the mixing tank is started. The stirring force in the mixing tank can evenly disperse the defluorination residue dry powder in the process water, avoiding local accumulation of dry powder and the formation of clumps. For example, defluorination residue dry powder and process water are added to the mixing tank. The initial addition amount of defluorination residue dry powder is set to 500 kg, and the initial addition amount of process water is set to 1200 L. Then, the mixing tank is started, the stirring speed is set to 150 r / min, and stirring is continued for 15 min to allow the defluorination residue dry powder and process water to initially mix, break the dry powder agglomeration, and form a preliminary mixed slurry with relatively uniform component distribution.

[0042] S302. The solid content of the preliminary mixed slurry is monitored by a solid content detector to obtain slurry solid content data. In this embodiment, a solids content detector is installed in the mixing tank and is used to measure the mass percentage of defluorination residue dry powder in the slurry in real time.

[0043] Before monitoring the solids content of the initial mixed slurry, the solids content detector needs to be started, the detection frequency is set to once every two minutes, and the detection accuracy is set to ±0.5%. Then, the detector probe is inserted into the initial mixed slurry to collect the mass percentage data of solid particles in the slurry in real time. The data display delay is controlled within ≤3s. Furthermore, the solids content data generated by the detector is used to determine whether the current solids content of the slurry is within the target range of 20%~30%.

[0044] S303. Add process water or defluorinated residue dry powder to the preliminary mixed slurry according to the solid content data of the slurry, and maintain the stirring of the mixing tank to obtain a slurry mixture with a solid content of 20%~30%.

[0045] In this embodiment, if the solids content is >30%, process water is added to the initial mixed slurry, with a single addition amount set to 50L; if the solids content is <20%, defluorination residue dry powder is added, with a single addition amount set to 20kg. After the addition, the mixing tank is maintained at a speed of 150r / min, and stirring is continued for 10 minutes. The solids content is then verified again using a solids content detector until the slurry solids content stabilizes at 20%~30%, at which point the slurry mixture is obtained.

[0046] In this embodiment, the dry powder of defluorination residue is stirred and blended with process water to break up the agglomeration of the dry powder and avoid local clumping that could lead to inaccurate subsequent solids content detection. Then, real-time data is obtained using a solids content analyzer to replace experience-based judgment, eliminating blind feeding and ensuring accurate quantity control. Furthermore, based on the solids content data, process water or dry powder is added to the mixing tank in a targeted manner to stabilize the solids content at 20%~30%. This avoids both excessively high solids content causing pipe blockage and incomplete acidolysis reaction, and excessively low solids content leading to waste of defluorination residue and excessive consumption of subsequent sulfuric acid.

[0047] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A highly efficient method for recovering phosphorus and fluorine from defluorination residue, a byproduct of DCP production, characterized in that, The method includes: By adjusting the proportions of process water and defluorinated residue dry powder using a solids content analyzer, a slurry mixture with a solids content of 20% to 30% was obtained. The slurry mixture is pumped into the reactor, and then sulfuric acid is added to the reactor at a mass ratio of sulfuric acid to the slurry mixture of 0.08~0.1:1 to obtain a sulfuric acid slurry mixture. The sulfuric acid slurry mixture is kept at a reaction temperature of 75-80°C in the reactor for 4-5 hours to obtain an acid hydrolysis slurry. The acid hydrolysis slurry is fed to a plate and frame filter press for solid-liquid separation to obtain a phosphorus and fluorine liquid phase recovery liquid and solid residue. Determine whether the solid residue meets one or more of the following conditions: water-soluble phosphorus content > 0.86% or fluoride content > 1.36%; If so, the phosphorus and fluorine recovery operation is repeated on the solid residue.

2. The efficient method for recovering phosphorus and fluorine according to claim 1, characterized in that, The phosphorus content of the phosphorus and fluoride liquid phase recovery solution is 46214~126735 mg / L, and the fluoride content is 2755~23540 mg / L.

3. The efficient method for recovering phosphorus and fluorine according to claim 1, characterized in that, After conveying the acid hydrolysis slurry to a plate and frame filter press for solid-liquid separation to obtain a phosphorus and fluorine liquid recovery liquid and solid residue, the method further includes: Determine whether the phosphorus and fluorine liquid phase recovery solution meets the requirements of phosphorus recovery rate ≥ 60% and fluorine recovery rate ≥ 70%; If so, maintain the current sulfuric acid addition amount, the reaction temperature in the reactor, and the reaction time, and recycle the phosphorus and fluorine liquid phase recovery solution that meets the phosphorus and fluorine recovery rate.

4. The efficient method for recovering phosphorus and fluorine according to claim 3, characterized in that, After determining whether the phosphorus and fluorine liquid phase recovery solution meets the requirements of phosphorus recovery rate ≥ 60% and fluorine recovery rate ≥ 70%, the method further includes: If not, one or more of the following should be adjusted: the amount of sulfuric acid added, the reaction temperature, or the reaction time. The phosphorus and fluorine liquid phase recovery solution that does not meet the phosphorus and fluorine recovery rate should be recycled.

5. The efficient method for recovering phosphorus and fluorine according to claim 4, characterized in that, The adjustment of the amount of sulfuric acid added includes: The amount of sulfuric acid added is increased within the range of 0.08 to 0.1:1 (mass ratio of sulfuric acid added to slurry mixture).

6. The efficient method for recovering phosphorus and fluorine according to claim 4, characterized in that, The adjustment of the reaction time in the reactor includes: The reaction time in the reactor is extended within the range of 4 to 5 hours.

7. The efficient method for recovering phosphorus and fluorine according to claim 4, characterized in that, The adjustment of the reaction temperature in the reactor includes: The temperature inside the reactor is increased within the reaction temperature range of 75~80℃.

8. The efficient method for recovering phosphorus and fluorine according to claim 1, characterized in that, The process of adjusting the proportions of process water and defluorination residue dry powder using a solids content analyzer to obtain a slurry mixture with a solids content of 20% to 30% includes: Add defluorinated residue dry powder and process water to the mixing tank, and start the mixing tank to stir, to obtain a preliminary mixed slurry; The solid content of the preliminary mixed slurry was monitored using a solid content analyzer to obtain slurry solid content data; According to the solid content data of the slurry, the process water or the defluorination residue dry powder is added to the preliminary mixed slurry, and the stirring of the mixing tank is maintained to obtain a slurry mixture with a solid content of 20%~30%.

9. The efficient method for recovering phosphorus and fluorine according to claim 1, characterized in that, After determining whether the solid residue meets one or more of the following conditions: water-soluble phosphorus content > 0.86% or fluoride content > 1.36%, the method further includes: If not, the solid residue will be collected and disposed of as harmless waste.

10. The efficient method for recovering phosphorus and fluorine according to any one of claims 1 to 9, characterized in that, The process water has a phosphorus content of 0.03 mg / L and a fluoride content of 0.06 mg / L.

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