Method for extracting impurities in phosphoric acid by coupling impinging stream with ultrasonic enhanced mixing

Abstract

The present application relates to a kind of methods for impurities in wet-process phosphoric acid by impinging stream coupled with ultrasound enhanced mixing extraction, the method comprising the following steps: wet-process phosphoric acid is aqueous phase, and extractant system is organic phase, and aqueous phase and organic phase are formed into two jets respectively to carry out impinging and mixing extraction, while ultrasound is applied to enhance the mixing extraction process of aqueous phase and organic phase, then liquid separation is carried out, and purified phosphoric acid and loaded extractant are obtained.The present application enhances the extraction process by using the way of impinging stream coupled with ultrasound, which is beneficial to the enhanced dispersion and mixing of wet-process phosphoric acid and extractant, thereby effectively removing impurities in wet-process phosphoric acid.

Description

Technical Field

[0001] This invention relates to the field of wet phosphoric acid purification technology, specifically to a method for impurity extraction from wet phosphoric acid by impingement flow coupled with ultrasonic enhancement. Background Technology

[0002] Phosphoric acid is an important chemical raw material. In industrial production, it is mainly divided into thermal phosphoric acid and wet phosphoric acid based on different extraction processes. Wet phosphoric acid is primarily produced by reacting phosphate rock powder with an acid solution (such as sulfuric acid), followed by a series of refining steps including filtration, deoxygenation, impurity removal, extraction, and purification. Currently, wet phosphoric acid is gradually replacing thermal phosphoric acid due to its advantages such as readily available raw materials, lower cost, high phosphorus conversion and recovery rates, and low energy consumption. In developed countries, it accounts for 80% of industrial phosphoric acid production. However, due to the relatively underdeveloped purification technology of wet phosphoric acid in my country, its production is mainly concentrated in the low-end product sector. The resulting product contains many impurities and is primarily used in the fertilizer industry, severely limiting its application in other fields. In recent years, with the rising cost of yellow phosphorus and advancements in purification technology, wet phosphoric acid has gradually gained a cost advantage.

[0003] However, wet-process phosphoric acid, being a product of acid-mineral reaction, contains numerous impurities, such as metal ions like iron, aluminum, calcium, and magnesium, as well as chloride and sulfate ions. These impurities not only affect product quality but also damage production equipment and the environment. Furthermore, it requires purification and concentration before it can be used to produce industrial-grade and feed-grade phosphates. To address the high impurity content in wet-process phosphoric acid, pretreatment is necessary to remove these impurities before its high-quality resource utilization.

[0004] For example, CN114044498A discloses a wet-process phosphoric acid purification method, in which MIBK and alcohol are combined in a certain mass ratio to form an extractable organic phase, which is then added to sulfuric acid wet-process phosphoric acid for extraction. After extraction, the organic phase is washed with a phosphoric acid washing agent. CN116750735A discloses a wet-process phosphoric acid purification method, which first uses a highly selective cationic extractant to remove metal cations such as iron, magnesium, and aluminum, and then concentrates, suspends crystallizes, washes, and dilutes to obtain high-purity phosphoric acid. CN115608002A discloses an apparatus and method for enhancing the extraction of phosphate rock acid hydrolysis slurry. By setting a fluidized mixing section in the tower and introducing microbubbles into the extractant to form a multiphase flow, efficient extraction of phosphate rock acid hydrolysis slurry is achieved.

[0005] However, existing methods for removing impurities from wet-process phosphoric acid are insufficient for effectively mixing the slurry and extractant, resulting in low extraction rates that fail to meet production demands. Therefore, providing a method that can effectively promote the mixing of phosphoric acid and the organic phase, thereby improving extraction efficiency and removing impurities from wet-process phosphoric acid, is a technical problem that needs to be solved. Summary of the Invention

[0006] To address the above problems, the present invention aims to provide a method for impurity extraction from wet-process phosphoric acid by impinging flow coupled with ultrasonic waves. Compared with the prior art, the present invention enhances the extraction process by using impinging flow coupled with ultrasonic waves, which is beneficial for the enhanced dispersion and mixing of wet-process phosphoric acid and extractant, thereby effectively removing impurities from wet-process phosphoric acid.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] This invention provides a method for impurity extraction from wet-process phosphoric acid using impingement flow coupled with ultrasonic enhancement, the method comprising the following steps:

[0009] Using wet-process phosphoric acid as the aqueous phase and the extractant system as the organic phase, the aqueous and organic phases are formed into two jets that collide and mix for extraction. Ultrasonic waves are applied to enhance the mixing and extraction process of the aqueous and organic phases. The mixture is then separated to obtain purified phosphoric acid and loaded extractant.

[0010] In this invention, the aqueous phase and organic phase are mixed and extracted in the form of impinging flow, and ultrasonic waves are introduced to enhance the mixing process. This achieves efficient mixing of wet phosphoric acid and extractant at both the microscopic and macroscopic levels, which is beneficial for promoting sufficient cation exchange and complexation reactions between the extractant and impurity ions, thereby accelerating the extraction process and improving the extraction rate of impurities such as iron and aluminum in wet phosphoric acid.

[0011] Preferably, the extractant used in the extractant system includes any one or a combination of at least two of the following: trialkylphosphine oxide (TRPO), tributyl phosphate (TBP), di(2,4,4-trimethylpentyl)phosphite (P272), dimethylheptyl methylphosphonate (P350), di(2-ethylhexyl) phosphate (P204), 2-ethylhexyl phosphate mono-2-ethylhexyl (P507), ethyl acetate, amyl acetate, methyl isobutyl ketone, cyclohexanone, isoamyl alcohol, trialkylmethylamine, didecylamine, or trioctylamine.

[0012] In this invention, the preferred extractant contains P=O and P-OH, and is applicable to a wide range of phosphoric acid concentrations. It can meet the requirements for use in wet-process phosphoric acid with a P2O5 mass concentration of 5-80%, and can efficiently extract iron and aluminum ions from wet-process phosphoric acid.

[0013] In this invention, the extractant system includes an extractant and a diluent. The diluent can be any diluent commonly used for extraction in the art, such as kerosene, sulfonated kerosene, cyclohexane, xylene, n-heptane, n-hexane, o-xylene, m-xylene, butyl acetate, or isoamyl acetate, or a combination of at least two of these.

[0014] Preferably, the mass concentration of the extractant in the extractant system is 5-65%, for example, it can be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60% or 65%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] Preferably, the reaction time for the mixed extraction is 1-60 min, for example, it can be 1 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 60 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] Preferably, the temperature of the mixed extraction is 20-90℃, for example, it can be 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃ or 90℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0017] Preferably, the mixture is allowed to stand after extraction.

[0018] Preferably, the settling time is 1-2 hours, for example, it can be 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours or 2 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] Preferably, the wet-process phosphoric acid comprises wet-process phosphoric acid obtained by acid decomposition of phosphate rock powder followed by separation and purification.

[0020] Preferably, the wet-process phosphoric acid contains 10-40% P2O5 by mass percentage, for example, 10%, 15%, 20%, 25%, 30%, 35%, or 40%, but is not limited to the listed values; other unlisted values ​​within the range are also applicable; 0.1-1.2% Fe, for example, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, or 1.2%, but is not limited to the listed values; other unlisted values ​​within the range are also applicable; and 0.3-3.5% Al, for example, 0.3%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, or 3.5%, but is not limited to the listed values; other unlisted values ​​within the range are also applicable.

[0021] In this invention, the impurities in the wet-process phosphoric acid include, for example, Mg in addition to Fe and Al. This invention also has a certain removal effect on Mg.

[0022] Preferably, the maximum velocity of the liquid nozzles of the aqueous phase and the organic phase is independently 0.5-10 m / s, for example, it can be 0.5 m / s, 1 m / s, 1.5 m / s, 2 m / s, 2.5 m / s, 3 m / s, 3.5 m / s, 4 m / s, 4.5 m / s, 5 m / s, 5.5 m / s, 6 m / s, 6.5 m / s, 7 m / s, 7.5 m / s, 8 m / s, 8.5 m / s, 9 m / s, 9.5 m / s or 10 m / s, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0023] Preferably, the flow rates of the aqueous phase and the organic phase in the reactor are each independently 5-25 L / h, for example, 5 L / h, 6 L / h, 8 L / h, 10 L / h, 12 L / h, 14 L / h, 16 L / h, 18 L / h, 20 L / h, 22 L / h, 24 L / h or 25 L / h, but are not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] Preferably, the frequency of the ultrasound in the mixed extraction is 20-100kHz, for example, it can be 20kHz, 30kHz, 40kHz, 50kHz, 60kHz, 70kHz, 80kHz, 90kHz or 100kHz, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0025] Preferably, the loaded extractant is regenerated to obtain a regenerated extractant that is reused in the mixed extraction process.

[0026] Preferably, the stripping agent used for regeneration includes any one of dilute hydrochloric acid, dilute nitric acid, ammonium oxalate, or water.

[0027] Preferably, the concentrations of the dilute hydrochloric acid, dilute nitric acid, and ammonium oxalate are each independently 0.1-1 mol / L, for example, 0.1 mol / L, 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L, or 1 mol / L, but are not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Preferably, the regeneration time is 10-30 min, for example, it can be 10 min, 12 min, 14 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min or 30 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Preferably, the mixing and extraction process is carried out in an impinging flow coupled ultrasonic reactor.

[0030] Preferably, the impingement flow coupled ultrasonic reactor includes an organic phase inlet and an aqueous phase inlet.

[0031] Preferably, nozzles are provided for the organic phase inlet and the aqueous phase inlet, respectively.

[0032] Preferably, an ultrasonic generator is provided at the bottom of the impact flow coupled ultrasonic reactor.

[0033] Preferably, the bottom outlet of the impinging flow coupled ultrasonic reactor is connected to a liquid separation device.

[0034] Preferably, the upper organic phase outlet of the liquid separator is connected to the loaded extractant collection device.

[0035] Preferably, the bottom aqueous phase outlet of the separator is connected to the purified phosphoric acid collection device.

[0036] In this invention, the aqueous phase and the organic phase are fed into the reactor through the aqueous phase inlet and the organic phase inlet, respectively, and two jets are formed through the nozzle. The two jets collide and mix, and ultrasonic waves are applied by the ultrasonic generator at the bottom to further enhance the mixing and extraction process. After mixing and extraction, the liquid enters the separator through the bottom outlet of the reactor. The aqueous phase and the organic phase are allowed to stand and separate into layers. The loaded extractant is collected through the upper organic phase outlet, and the purified phosphoric acid is collected through the bottom aqueous phase outlet.

[0037] As a preferred embodiment of the present invention, the method includes the following steps:

[0038] Using wet-process phosphoric acid as the aqueous phase and an extractant system as the organic phase, the extractant system comprises any one or a combination of at least two of the following: trialkylphosphine oxide, tributyl phosphate, di(2,4,4-trimethylpentyl)phosphine, dimethylheptyl methylphosphonate, di(2-ethylhexyl) phosphate, 2-ethylhexyl phosphate mono-2-ethylhexyl ester, ethyl acetate, amyl acetate, methyl isobutyl ketone, cyclohexanone, isoamyl alcohol, trialkylmethylamine, didecylamine, or trioctylamine. The mass concentration of the extractant in the extractant system is 5-65%. The phases are formed into two jets that collide and mix for extraction. The maximum velocity of the liquid nozzles of the aqueous and organic phases is 0.5-10 m / s, and the flow rates of the aqueous and organic phases in the reactor are 5-25 L / h, respectively. The reaction time of the mixed extraction is 1-60 min, and the temperature of the mixed extraction is 20-90℃. During the mixed extraction, ultrasound at 20-100 kHz is applied to enhance the mixed extraction process of the aqueous and organic phases. After standing for 1-2 h, the liquid is separated to obtain purified phosphoric acid and the loaded extractant.

[0039] The loaded extractant is regenerated for 10-30 minutes to obtain a regenerated extractant that is reused in the mixed extraction process. The back-extraction agent used for regeneration includes any one of dilute hydrochloric acid, dilute nitric acid, ammonium oxalate, or water, and the concentrations of the dilute hydrochloric acid, dilute nitric acid, and ammonium oxalate are each independently 0.1-1 mol / L.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) In this invention, the extraction process is enhanced by using an impingement flow coupled with ultrasonic waves, which promotes the dispersion and mixing between wet phosphoric acid and the extractant, thereby significantly improving the extraction rate and effectively reducing the impurity content in wet phosphoric acid. Under optimal conditions, the extraction efficiency of Fe in wet phosphoric acid is significantly improved. 3+ The extraction rate reached over 97%, and the extraction efficiency for Al was [not specified]. 3+ The extraction rate reached over 74.75%, and under even better conditions, Fe... 3+ The extraction rate reached over 99%, Al 3+ The extraction rate reaches over 90%.

[0042] (2) The method for extracting impurities from wet-process phosphoric acid provided by the present invention has the advantages of fast extraction speed, significant effect, simple equipment and low cost, which provides solid technical support for the high-quality application of wet-process phosphoric acid. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the device system described in Embodiment 1 of the present invention;

[0044] Among them, 1-impact flow coupled ultrasonic reactor; 2-ultrasonic generator; 3-liquid separator; 4-loaded extractant collection device; 5-purified phosphoric acid collection device. Detailed Implementation

[0045] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0046] In one specific embodiment, the method for impurity extraction from wet-process phosphoric acid using impinging flow coupled ultrasound-enhanced mixing provided by the present invention is carried out in an apparatus system equipped with an impinging flow coupled ultrasound reactor, the apparatus system being as follows: Figure 1As shown, the device includes an impinging flow coupled ultrasonic reactor 1, a liquid separation device 3, a loaded extractant collection device 4, and a purified phosphoric acid collection device 5. The impinging flow coupled ultrasonic reactor 1 includes an organic phase inlet and an aqueous phase inlet, each equipped with a nozzle. An ultrasonic generator 2 is installed at the bottom of the impinging flow coupled ultrasonic reactor 1. The bottom outlet of the impinging flow coupled ultrasonic reactor 1 is connected to the liquid separation device 3. The upper organic phase outlet of the liquid separation device 3 is connected to the loaded extractant collection device 4, and the bottom aqueous phase outlet of the liquid separation device 3 is connected to the purified phosphoric acid collection device 5.

[0047] In this invention, the aqueous phase and the organic phase are fed into the reactor through the aqueous phase inlet and the organic phase inlet, respectively, and two jets are formed through the nozzle. The two jets collide and mix. At the same time, ultrasonic waves are applied through the ultrasonic generator 2 at the bottom, which can further enhance the mixing and extraction process. The mixed and extracted liquid enters the separator 3 through the bottom outlet of the reactor. The aqueous phase and the organic phase are allowed to stand and separate into layers. The loaded extractant is collected through the upper organic phase outlet, and the purified phosphoric acid is collected through the bottom aqueous phase outlet.

[0048] Example 1

[0049] This embodiment provides a method for impurity extraction from wet-process phosphoric acid using impinging flow coupled with ultrasonic enhancement. The method is performed in a device system equipped with an impinging flow coupled with an ultrasonic reactor, such as... Figure 1 As shown, the method includes an impingement flow coupled ultrasonic reactor 1, an ultrasonic generator 2, a liquid separator 3, a loaded extractant collection device 4, and a purified phosphoric acid collection device 5. The method includes the following steps:

[0050] Using wet-process phosphoric acid as the aqueous phase (containing 31% P2O5, 0.6% Fe, and 1.2% Al by mass percentage), and trialkylphosphine oxide as the extractant, with cyclohexane as the diluent, forming an organic phase, the extractant system has a mass concentration of 65%. The aqueous and organic phases are fed into the aqueous and organic phase inlets of the impinging flow coupled ultrasonic reactor 1, respectively. Two jets are generated through nozzles to collide and mix during extraction, resulting in intense collisions, shearing, compression, and stretching. Simultaneously, an ultrasonic generator 2 applies ultrasound at a frequency of 100 kHz, generating strong... Microjets and shock waves are used to achieve mixing at both the micro and macro levels. The mixing extraction temperature is 25°C, the reaction time is 60 min, the maximum velocity of the liquid nozzles of both the aqueous and organic phases is 9 m / s, and the flow rates of both the aqueous and organic phases are 25 L / h. After standing for 1.5 h, the liquid enters the liquid separator 3 through the bottom outlet of the impingement flow coupled ultrasonic reactor 1 to obtain purified phosphoric acid and loaded extractant. The loaded extractant is collected through the upper organic phase outlet to the loaded extractant collection device 4, and the purified phosphoric acid is collected through the bottom aqueous phase outlet to the purified phosphoric acid collection device 5.

[0051] The loaded extractant is regenerated for 25 minutes to obtain a regenerated extractant that is reused in the mixed extraction process. The back-extraction agent used for regeneration is 0.5 mol / L dilute hydrochloric acid.

[0052] Example 2

[0053] This embodiment provides a method for impurity extraction from wet-process phosphoric acid using impinging flow coupled with ultrasonic enhancement. The method is carried out in a device system equipped with an impinging flow coupled with an ultrasonic reactor, which is the same as in Embodiment 1. The method includes the following steps:

[0054] Using wet-process phosphoric acid as the aqueous phase (same as in Example 1), trialkylphosphine oxide as the extractant, and kerosene as the diluent, an extractant system was formed as the organic phase. The aqueous and organic phases were fed into the aqueous and organic phase inlets of the impinging flow coupled ultrasonic reactor, respectively. Two jets were generated through nozzles to collide and mix, resulting in intense collisions, shearing, compression, and stretching. Simultaneously, an ultrasonic generator applied ultrasound at a frequency of 60 kHz, generating strong micro-jet streams and shock waves to achieve mixing at both the micro and macro levels. The mixing extraction temperature was 80°C, the reaction time was 20 min, the extractant mass concentration in the extractant system was 65%, the maximum velocity of the liquid nozzles of both the aqueous and organic phases was 8 m / s, and the flow rates of both the aqueous and organic phases were 8 L / h. After standing for 1 h, the liquid was separated into a liquid separator through the bottom outlet of the impinging flow coupled ultrasonic reactor to obtain purified phosphoric acid and loaded extractant. The loaded extractant was collected through the upper organic phase outlet to the loaded extractant collection device, and the purified phosphoric acid was collected through the bottom aqueous phase outlet to the purified phosphoric acid collection device.

[0055] The loaded extractant is regenerated for 15 minutes to obtain a regenerated extractant that is reused in the mixed extraction process. The back-extraction agent used for regeneration is water.

[0056] Example 3

[0057] This embodiment provides a method for impurity extraction from wet-process phosphoric acid using impinging flow coupled with ultrasonic enhancement. The method is carried out in a device system equipped with an impinging flow coupled with an ultrasonic reactor, which is the same as in Embodiment 1. The method includes the following steps:

[0058] Using wet-process phosphoric acid as the aqueous phase (same as in Example 1), and 2-ethylhexyl phosphate mono-2-ethylhexyl ester as the extractant and cyclohexane as the diluent, an extractant system was formed as the organic phase. The aqueous and organic phases were fed into the aqueous and organic phase inlets of an impinging flow coupled ultrasonic reactor, respectively. Two jets were generated through nozzles to collide and mix during extraction, resulting in intense collisions, shearing, compression, and stretching. Simultaneously, an ultrasonic generator applied ultrasound at a frequency of 40 kHz, generating strong microjets and shock waves, achieving mixing at both the microscopic and macroscopic levels. This mixed extraction... The temperature was 25℃, the reaction time was 10 min, the mass concentration of the extractant in the extractant system was 55%, the maximum velocity of the liquid nozzles of both the aqueous and organic phases was 9 m / s, and the flow rates of both the aqueous and organic phases were 15 L / h. After standing for 2 h, the liquid was separated into a liquid separator through the bottom outlet of the impinging flow coupled ultrasonic reactor to obtain purified phosphoric acid and loaded extractant. The loaded extractant was collected through the upper organic phase outlet to the loaded extractant collection device, and the purified phosphoric acid was collected through the bottom aqueous phase outlet to the purified phosphoric acid collection device.

[0059] The loaded extractant is regenerated for 10 minutes to obtain a regenerated extractant that is reused in the mixed extraction process. The back-extraction agent used for regeneration is 1 mol / L dilute nitric acid.

[0060] Example 4

[0061] This embodiment provides a method for impurity extraction from wet-process phosphoric acid using impinging flow coupled with ultrasonic enhancement. The method is carried out in a device system equipped with an impinging flow coupled with an ultrasonic reactor, which is the same as in Embodiment 1. The method includes the following steps:

[0062] Using wet-process phosphoric acid as the aqueous phase (same as in Example 1), and 2-ethylhexyl phosphate mono-2-ethylhexyl ester as the extractant and butyl acetate as the diluent, an extractant system was formed as the organic phase. The aqueous and organic phases were respectively fed into the aqueous and organic phase inlets of an impinging flow coupled ultrasonic reactor. Two jets were generated through nozzles to collide and mix during extraction, resulting in intense collisions, shearing, compression, and stretching. Simultaneously, an ultrasonic generator applied ultrasound at a frequency of 100 kHz, generating strong microjets and shock waves, achieving mixing at both the microscopic and macroscopic levels. The extraction temperature was 80℃, the reaction time was 40 min, the mass concentration of the extractant in the extractant system was 10%, the maximum velocity of the liquid nozzles of both the aqueous and organic phases was 1 m / s, and the flow rates of both the aqueous and organic phases were 5 L / h. After standing for 2 h, the liquid was separated into a liquid separator through the bottom outlet of the impinging flow coupled ultrasonic reactor to obtain purified phosphoric acid and loaded extractant. The loaded extractant was collected through the upper organic phase outlet to the loaded extractant collection device, and the purified phosphoric acid was collected through the bottom aqueous phase outlet to the purified phosphoric acid collection device.

[0063] The loaded extractant is regenerated for 20 minutes to obtain a regenerated extractant that is reused in the mixed extraction process. The back-extraction agent used for regeneration is 1 mol / L ammonium oxalate.

[0064] Example 5

[0065] This embodiment provides a method for impurity extraction from wet-process phosphoric acid using impinging flow coupled with ultrasonic enhancement. The method is carried out in a device system equipped with an impinging flow coupled with an ultrasonic reactor, which is the same as in Embodiment 1. The method includes the following steps:

[0066] Using wet-process phosphoric acid as the aqueous phase (same as in Example 1), dimethylheptyl methylphosphonate as the extractant, and kerosene as the diluent, an extractant system consisting of an organic phase and an aqueous phase was fed into the aqueous phase inlet and organic phase inlet of an impinging flow coupled ultrasonic reactor, respectively. Two jets were generated through nozzles to collide and mix, resulting in intense collisions, shearing, compression, and stretching. Simultaneously, an ultrasonic generator applied ultrasound at a frequency of 20 kHz, generating strong micro-jet streams and shock waves to achieve mixing at both the microscopic and macroscopic levels. The mixing extraction temperature was 25°C, the reaction time was 10 min, the extractant mass concentration in the extractant system was 30%, the maximum velocity of the liquid nozzles of both the aqueous and organic phases was 10 m / s, and the flow rates of both the aqueous and organic phases were 5 L / h. After standing for 1 h, the liquid was separated into a liquid separator through the bottom outlet of the impinging flow coupled ultrasonic reactor to obtain purified phosphoric acid and a loaded extractant. The loaded extractant was collected through the upper organic phase outlet to a loaded extractant collection device, and the purified phosphoric acid was collected through the bottom aqueous phase outlet to a purified phosphoric acid collection device.

[0067] The loaded extractant is regenerated for 15 minutes to obtain a regenerated extractant that is reused in the mixed extraction process. The back-extraction agent used for regeneration is 1 mol / L ammonium oxalate.

[0068] Example 6

[0069] This embodiment provides a method for impurity extraction from wet-process phosphoric acid using impinging flow coupled with ultrasonic enhancement. The method is carried out in a device system equipped with an impinging flow coupled with an ultrasonic reactor, which is the same as in Embodiment 1. The method includes the following steps:

[0070] Using wet-process phosphoric acid as the aqueous phase (same as in Example 1), and dimethylheptyl methylphosphonate as the extractant and hexane as the diluent, the extractant system was used as the organic phase. The aqueous phase and organic phase were fed into the aqueous phase inlet and organic phase inlet of the impinging flow coupled ultrasonic reactor, respectively. Two jets were generated through nozzles to collide and mix, resulting in intense collisions, shearing, compression, and stretching. At the same time, an ultrasonic generator applied ultrasonic waves at a frequency of 80 kHz, generating strong micro-jet streams and shock waves to achieve mixing at both the micro and macro levels. The mixing extraction temperature was 80°C, the reaction time was 60 min, the mass concentration of the extractant in the extractant system was 5%, the maximum velocity of the liquid nozzles of both the aqueous and organic phases was 7 m / s, and the flow rates of both the aqueous and organic phases were 6 L / h. After standing for 2 h, the liquid was separated into a liquid separator through the bottom outlet of the impinging flow coupled ultrasonic reactor to obtain purified phosphoric acid and loaded extractant. The loaded extractant was collected through the upper organic phase outlet to the loaded extractant collection device, and the purified phosphoric acid was collected through the bottom aqueous phase outlet to the purified phosphoric acid collection device.

[0071] The loaded extractant is regenerated for 30 minutes to obtain a regenerated extractant that is reused in the mixed extraction process. The back-extraction agent used for regeneration is 1 mol / L dilute nitric acid.

[0072] Example 7

[0073] This embodiment provides a method for impurity extraction from wet-process phosphoric acid using impingement flow coupled with ultrasonic enhancement. The only difference between this method and Embodiment 1 is that the frequency of the ultrasonic waves is 15 kHz.

[0074] Example 8

[0075] This embodiment provides a method for impurity extraction from wet-process phosphoric acid using impingement flow coupled with ultrasonic enhancement. The only difference between this method and Embodiment 1 is that the frequency of the ultrasonic wave is 120 kHz.

[0076] Example 9

[0077] This embodiment provides a method for impurity extraction from wet-process phosphoric acid using impingement flow coupled with ultrasonic enhancement. The only difference between this method and Example 1 is that the maximum velocity of the liquid nozzles in both the aqueous and organic phases is 0.3 m / s.

[0078] Example 10

[0079] This embodiment provides a method for impurity extraction from wet-process phosphoric acid using impingement flow coupled with ultrasonic enhancement. The only difference between this method and Example 1 is that the maximum velocity of the liquid nozzles in both the aqueous and organic phases is 15 m / s.

[0080] Comparative Example 1

[0081] This comparative example provides a method for impurity extraction from wet-process phosphoric acid using impingement flow coupled with ultrasonic enhancement. The only difference from Example 1 is that the impingement flow coupled ultrasonic reactor is replaced with a stirred reactor, i.e., the mixing and extraction process is carried out in the stirred reactor, and the stirring rate is controlled at 200 r / min.

[0082] Fe in purified phosphoric acid obtained in Examples 1-10 and Comparative Example 1 3+ And Al 3+ The mass percentage content was determined using the method specified in GB / T 36244-2018, and the results are shown in Table 1.

[0083] Table 1

[0084] <![CDATA[Fe 3+ (%)]]> <![CDATA[Fe 3+ Extraction rate (%) <![CDATA[Al 3+ (%)]]> <![CDATA[Al 3+ Extraction rate (%) Example 1 0.000 100.00 0.109 90.92 Example 2 0.001 99.83 0.112 90.67 Example 3 0.001 99.83 0.119 90.08 Example 4 0.003 99.50 0.137 88.58 Example 5 0.005 99.17 0.154 87.17 Example 6 0.018 97.00 0.303 74.75 Example 7 0.149 75.17 0.457 61.92 Example 8 0.001 99.83 0.118 90.17 Example 9 0.174 71.00 0.562 53.17 Example 10 0.101 83.17 0.351 70.75 Comparative Example 1 0.216 64.00 0.778 35.17

[0085] The following points can be observed from Table 1:

[0086] (1) As can be seen from the data in Examples 1-6, taking the removal of impurities such as Fe and Al from wet-process phosphoric acid as an example, the method provided by the present invention enhances the mixing and extraction process by coupling ultrasonic waves with impinging flow. Under optimal conditions, it can effectively remove Fe from wet-process phosphoric acid. 3+ The extraction rate reached over 97%, and the extraction efficiency for Al was [not specified]. 3+ The extraction rate reached over 74.75%, and under even better conditions, Fe... 3+ The extraction rate reached over 99%, Al 3+ The extraction rate reaches over 90%.

[0087] (2) A comprehensive comparison of the data from Examples 1 and 7-8 shows that the only difference between Examples 7-8 and Example 1 is that the frequency of the ultrasound is outside the preferred range of this invention. In Example 7, the frequency of the ultrasound was too low, resulting in limited enhancement of the mixing and extraction process. In Example 8, the frequency of the ultrasound was too high, which had little impact on the extraction rate but led to increased energy consumption. Therefore, this invention can further improve the mixing and extraction effect while reducing energy consumption by optimally controlling the frequency of the ultrasound.

[0088] (3) A comprehensive comparison of the data from Examples 1 and 9-10 shows that the only difference between Examples 9-10 and Example 1 is that the maximum velocity of the liquid nozzles in the aqueous and organic phases is not within the preferred range of this invention. In Examples 9-10, the Fe... 3+ And Al 3+ The extraction rate decreased significantly. Therefore, it can be seen that by optimizing the control of the maximum velocity of the liquid nozzles of the aqueous and organic phases, the present invention can enhance the mixing and mass transfer between the fluids, ensure the contact time between the aqueous and organic phases, and thus further improve the mixed extraction effect.

[0089] (4) By comparing the data of Example 1 and Comparative Example 1, it can be seen that the only difference between Comparative Example 1 and Example 1 is that the method of impinging flow coupled with ultrasound is not used for enhancement, and extraction is carried out only under stirring conditions. The extraction rate in Example 1 is significantly higher than that in Comparative Example 1. It can be seen that the method provided by the present invention can effectively improve the extraction rate of impurities in wet phosphoric acid by using impinging flow coupled with ultrasound to enhance the mixing extraction process.

[0090] In summary, by employing an impingement flow coupled with ultrasonic waves to enhance the extraction process, this invention can promote the dispersion and mixing between wet-process phosphoric acid and the extractant, thereby significantly improving the extraction rate and effectively reducing the impurity content in wet-process phosphoric acid.

[0091] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for the extraction of impurities from a wet-process phosphoric acid by impinging stream coupled ultrasonic intensification mixing, characterized in that, The method comprises the following steps: The method comprises the following steps: The maximum velocity of the liquid jet of the water phase and the organic phase is independently 0.5-10 m / s. The frequency of the ultrasonic wave in the mixed extraction is 20-100 kHz.

2. The method of claim 1, wherein, The extractant used in the extractant system comprises any one or a combination of at least two of trialkyl phosphine oxide, tributyl phosphate, di(2,4,4-trimethylpentyl) phosphinic acid, dimethylheptyl methylphosphonate, di(2-ethyl-hexyl) phosphate, 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester, ethyl acetate, amyl acetate, methyl isobutyl ketone, cyclohexanone, isoamyl alcohol, trialkyl methylamine, didecylamine or trioctylamine.

3. The method of claim 1, wherein, The mass concentration of the extractant in the extractant system is 5-65%.

4. The method of claim 1, wherein, The reaction time of the mixed extraction is 1-60 min.

5. The method of claim 1, wherein, The temperature of the mixed extraction is 20-90℃.

6. The method of claim 1, wherein, The mixed extraction is followed by standing.

7. The method of claim 6, wherein, The standing time is 1-2 h.

8. The method of claim 1, wherein, The wet-process phosphoric acid comprises wet-process phosphoric acid obtained by sequentially separating and purifying phosphorite powder after acid leaching.

9. The method of claim 1, wherein, The wet-process phosphoric acid contains 10-40% P2O5, 0.1-1.2% Fe and 0.3-3.5% Al by mass percentage.

10. The method of claim 1, wherein, The flow rate of the water phase and the organic phase in the reactor is independently 5-25 L / h.

11. The method of claim 1, wherein, The loaded extractant is regenerated to obtain regenerated extractant for reuse in the mixed extraction process.

12. The method of claim 11, wherein, The stripping agent used in the regeneration comprises any one of dilute hydrochloric acid, dilute nitric acid, ammonium oxalate or water.

13. The method of claim 12, wherein, The concentration of the dilute hydrochloric acid, the dilute nitric acid and the ammonium oxalate is independently 0.1-1 mol / L.

14. The method of claim 11, wherein, The regeneration time is 10-30 min.

15. The method of claim 1, wherein, The mixed extraction process is carried out in an impinging stream coupled ultrasonic wave reactor.

16. The method of claim 15, wherein, The impinging stream coupled ultrasonic wave reactor comprises an organic phase inlet and a water phase inlet.

17. The method of claim 16, wherein, The organic phase inlet and the water phase inlet are respectively provided with nozzles.

18. The method of claim 15, wherein, The bottom of the impinging stream coupled ultrasonic wave reactor is provided with an ultrasonic wave generator.

19. The method of claim 15, wherein, The bottom outlet of the impinging stream coupled ultrasonic wave reactor is connected with a liquid separation device.

20. The method of claim 19, wherein, The upper organic phase outlet of the liquid separation device is connected with a loaded extractant collection device.

21. The method of claim 19, wherein, The bottom water phase outlet of the liquid separation device is connected with a purified phosphoric acid collection device.

22. The method of claim 1, wherein, The method comprises the following steps: The wet-process phosphoric acid is used as the aqueous phase, and an extractant system is used as the organic phase, the extractant used in the extractant system includes any one or a combination of at least two of trialkyl phosphine oxide, tributyl phosphate, di(2,4,4-trimethylpentyl) phosphinic acid, dimethylheptyl methylphosphonate, di(2-ethyl-hexyl) phosphate, 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester, ethyl acetate, amyl acetate, methyl isobutyl ketone, cyclohexanone, isoamyl alcohol, trialkylmethylamine, didecylamine or trioctylamine, the mass concentration of the extractant in the extractant system is 5-65%, the aqueous phase and the organic phase are formed into two jets respectively and are mixed and extracted by impingement, the liquid jet maximum velocity of the aqueous phase and the organic phase is independently 0.5-10 m / s, the flow rate of the aqueous phase and the organic phase in the reactor is independently 5-25 L / h, the reaction time of the mixed extraction is 1-60 min, the temperature of the mixed extraction is 20-90℃, the mixed extraction process of the aqueous phase and the organic phase is simultaneously strengthened by ultrasonic waves with a frequency of 20-100 kHz, and then the mixture is allowed to stand for 1-2 h, and then the liquid is separated, to obtain purified phosphoric acid and loaded extractant. The loaded extractant is regenerated for 10-30 min to obtain regenerated extractant for reuse in the mixed extraction process, the stripping agent used in the regeneration includes any one of dilute hydrochloric acid, dilute nitric acid, ammonium oxalate or water, and the concentration of the dilute hydrochloric acid, the dilute nitric acid and the ammonium oxalate is independently 0.1-1 mol / L.

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