Method for extracting impurities in wet-process phosphoric acid through impinging stream coupled ultrasonic enhanced mixing

Abstract

The invention relates to a method for extracting impurities in wet-process phosphoric acid through impinging stream coupled ultrasonic wave intensified mixing, which comprises the following steps: by taking wet-process phosphoric acid as a water phase and an extracting agent system as an organic phase, respectively forming two jets from the water phase and the organic phase for impinging and carrying out mixed extraction, meanwhile, ultrasonic waves are applied to strengthen the mixed extraction process of the water phase and the organic phase, then liquid separation is conducted, and purified phosphoric acid and the loaded extraction agent are obtained. The extraction process is enhanced in an impinging stream coupling ultrasonic wave mode, and enhanced dispersion and mixing of wet-process phosphoric acid and the extraction agent are facilitated, so that impurities in wet-process phosphoric acid are effectively removed.

Description

Technical Field

[0001] The invention relates to the technical field of wet-process phosphoric acid purification, and in particular to a method for extracting impurities in wet-process phosphoric acid by impinging flow coupled with ultrasonic enhanced mixed extraction. Background Art

[0002] Phosphoric acid is an important chemical raw material. In industrial production, it is mainly divided into thermal phosphoric acid and wet phosphoric acid according to different extraction processes. Wet phosphoric acid is mainly refined by reacting acid (such as sulfuric acid) with phosphate rock powder, and then successively undergoing filtration, deoxidation, impurity removal, extraction and purification process steps. At present, wet phosphoric acid has gradually replaced thermal phosphoric acid due to its advantages such as easy availability of raw materials, low cost, high phosphorus conversion rate and recovery rate, and low energy consumption. The proportion of industrial phosphoric acid in developed countries has reached 80%. Due to the relatively backward purification technology of wet phosphoric acid in my country, the production of wet phosphoric acid is mainly concentrated in the field of low-end products. The resulting products contain more impurities and are mostly used in the field of fertilizers. The application in other fields is greatly limited. In recent years, with the rising cost of yellow phosphorus and the advancement of purification technology, wet phosphoric acid has gradually gained cost advantages.

[0003] However, as a product of acid-ore reaction, wet-process phosphoric acid contains many impurities, such as metal ions such as iron, aluminum, calcium, magnesium, as well as chloride ions, sulfate ions, etc. These impurities not only affect product quality, but also damage production equipment and the environment, and need to be purified and concentrated before industrial-grade phosphates, feed-grade phosphates, etc. can be produced. In view of the high impurity content in wet-process phosphoric acid, it is necessary to pre-treat the phosphoric acid before high-quality resource utilization of wet-process phosphoric acid to remove impurities in the phosphoric acid.

[0004] For example, CN114044498A discloses a method for purifying wet-process phosphoric acid, in which MIBK and alcohol are prepared in a certain mass ratio to form an extraction organic phase, which is then added to sulfuric acid-process wet-process phosphoric acid for extraction, and then the extracted organic phase is washed with a phosphoric acid detergent; CN116750735A discloses a method for purifying wet-process phosphoric acid, in which a highly selective cationic extractant is first used to remove metal cations such as iron, magnesium, and aluminum, and then concentration, suspension crystallization, washing, and dilution are performed to obtain high-purity phosphoric acid; CN115608002A discloses a device and method for intensifying the extraction of phosphate ore acid hydrolysis slurry, in which a fluidized mixing section is arranged in a tower body, and microbubbles are introduced into the extractant to form a multiphase flow, thereby achieving efficient extraction of phosphate ore acid hydrolysis slurry.

[0005] However, the existing methods for removing impurities from wet-process phosphoric acid are difficult to effectively mix the slurry and the extractant, resulting in a low extraction rate and difficulty in meeting production needs. Therefore, providing a method that can fully promote the mixing of phosphoric acid and an organic phase, improve the extraction effect, and thus remove impurities from wet-process phosphoric acid is a technical problem that needs to be solved at present. Summary of the invention

[0006] In view of the above problems, the object of the present invention is to provide a method for enhanced mixed extraction of impurities in wet-process phosphoric acid by impinging stream coupled with ultrasound. Compared with the prior art, the present invention enhances the extraction process by using impinging stream coupled with ultrasound, which is beneficial to the enhanced dispersion and mixing of wet-process phosphoric acid and the extractant, thereby effectively removing impurities in wet-process phosphoric acid.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for extracting impurities in wet-process phosphoric acid by impinging flow coupled with ultrasonic enhanced mixed extraction, the method comprising the following steps:

[0009] With wet-process phosphoric acid as the aqueous phase and the extractant system as the organic phase, the aqueous phase and the organic phase are respectively formed into two jets for collision and mixed extraction, and ultrasonic waves are applied to enhance the mixed extraction process of the aqueous phase and the organic phase, and then the liquids are separated to obtain purified phosphoric acid and a loaded extractant.

[0010] In the present invention, the aqueous phase and the organic phase are mixed and extracted in the form of impinging streams, and ultrasonic wave is introduced to enhance the mixing process, so that efficient mixing of wet-process phosphoric acid and the extractant at the microscopic and macroscopic levels is achieved, which is beneficial to promoting sufficient cation exchange and complexation reaction between the extractant and the impurity ions, thereby accelerating the extraction process and improving the extraction rate of impurities such as iron and aluminum in the wet-process phosphoric acid.

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

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

[0013] In the present invention, the extractant system includes an extractant and a diluent. The diluent can be any diluent commonly used for extraction in the art, for example, it can be any one of 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 thereof.

[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, and other unlisted values ​​within the numerical range are also applicable.

[0015] Preferably, the reaction time of 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, and other unlisted values ​​within the numerical range are also applicable.

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

[0017] Preferably, the mixed extraction is followed by standing.

[0018] Preferably, the standing time is 1-2 hours, for example, 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, and other values ​​not listed within the numerical range are also applicable.

[0019] Preferably, the wet-process phosphoric acid includes wet-process phosphoric acid obtained by decomposing phosphate rock powder with acid solution and then separating and purifying it.

[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 not limited to the listed values, and other values ​​not listed in the numerical range are equally applicable; 0.1-1.2% Fe, for example, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1% or 1.2%, but not limited to the listed values, and other values ​​not listed in the numerical range are equally applicable; 0.3-3.5% Al, for example, 0.3%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3% or 3.5%, but not limited to the listed values, and other values ​​not listed in the numerical range are equally applicable.

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

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

[0023] Preferably, the flow rates of the aqueous phase and the organic phase in the reactor are 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, and other unlisted values ​​within the numerical range are also applicable.

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

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

[0026] Preferably, the stripping agent used for the 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, and other unlisted values ​​within the numerical range are equally 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, and other unlisted values ​​within the numerical range are also applicable.

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

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

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

[0032] Preferably, an ultrasonic generator is arranged at the bottom of the impinging 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 separation device is connected to a loaded extractant collecting device.

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

[0036] In the present invention, the aqueous phase and the organic phase are respectively fed from the aqueous phase inlet and the organic phase inlet, and two jets are formed through a nozzle, and the two jets are collided and mixed, and ultrasonic waves are applied through an ultrasonic generator at the bottom, which can further strengthen the mixed extraction process, and then the mixed extracted feed liquid enters a liquid separation device through the bottom outlet of the reactor, and the aqueous phase and the organic phase are statically separated, wherein 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 technical solution of the present invention, the method comprises the following steps:

[0038] The invention adopts wet-process phosphoric acid as an aqueous phase and an extractant system as an organic phase. The extractant used in the extractant system includes any one of trialkylphosphine oxide, tributyl phosphate, di(2,4,4-trimethylpentyl) hypophosphorous acid, dimethylheptyl methylphosphonate, di(2-ethyl-hexyl) phosphate, 2-ethylhexyl phosphate mono-2-ethylhexyl ester, ethyl acetate, amyl acetate, methyl isobutyl ketone, cyclohexanone, isopentanol, trialkylmethylamine, didecylamine or trioctylamine, or a combination of at least two thereof. The mass concentration of the extractant in the extractant system is 5-65%. The aqueous phase and the organic phase are mixed. The phases are formed into two jets to collide and undergo mixed extraction, the maximum speed of the liquid nozzles of the aqueous phase and the organic phase are independently 0.5-10 m / s, the flow rates of the aqueous phase and the organic phase in the reactor are 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° C., and 20-100 kHz ultrasonic waves are applied to strengthen the mixed extraction process of the aqueous phase and the organic phase, and then the mixture is allowed to stand for 1-2 hours, and then the liquids are separated to obtain purified phosphoric acid and a loaded extractant;

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

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

[0041] (1) The present invention uses an impinging flow coupled ultrasonic method to enhance the extraction process, which 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 the wet-process phosphoric acid. Under optimal conditions, the extraction rate of Fe in the wet-process phosphoric acid is reduced. 3+ The extraction rate of Al 3+ The extraction rate of Fe 3+ The extraction rate of 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, and provides solid technical support for the high-quality application of wet-process phosphoric acid. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0045] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0046] In a specific embodiment, the method for enhanced mixed extraction of impurities in wet-process phosphoric acid by impinging stream coupled with ultrasonic waves provided by the present invention is carried out in a device system provided with an impinging stream coupled with ultrasonic reactor, wherein the device system is as follows: Figure 1As shown, it includes an impinging flow coupled ultrasonic reactor 1, a liquid separation device 3, a loaded extractant collecting device 4 and a purified phosphoric acid collecting device 5. The impinging flow coupled ultrasonic reactor 1 includes an organic phase inlet and an aqueous phase inlet, and nozzles are respectively arranged on the organic phase inlet and the aqueous phase inlet. An ultrasonic generator 2 is arranged at the bottom of the impinging flow coupled ultrasonic reactor 1, and 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 collecting device 4, and the bottom aqueous phase outlet of the liquid separation device 3 is connected to the purified phosphoric acid collecting device 5.

[0047] In the present invention, the aqueous phase and the organic phase are respectively fed from the aqueous phase inlet and the organic phase inlet, and two jets are formed through a nozzle, and the two jets are collided and mixed, and ultrasonic waves are applied through the ultrasonic generator 2 at the bottom, which can further enhance the mixed extraction process. The mixed extracted feed liquid enters the liquid separation device 3 through the bottom outlet of the reactor, and the aqueous phase and the organic phase are statically separated into layers, wherein 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 enhanced mixed extraction of impurities in wet-process phosphoric acid by impinging flow coupled with ultrasonic waves. The method is carried out in a device system equipped with an impinging flow coupled with ultrasonic reactor, such as Figure 1 As shown, it includes an impinging flow coupled ultrasonic reactor 1, an ultrasonic generator 2, a liquid separation device 3, a loaded extractant collection device 4 and a purified phosphoric acid collection device 5, and the method includes the following steps:

[0050] Wet-process phosphoric acid is used as the aqueous phase (containing 31% P2O5, 0.6% Fe, and 1.2% Al in terms of mass percentage), trialkylphosphine oxide is used as the extractant, and cyclohexane is used as the diluent to form an extractant system as the organic phase. The mass concentration of the extractant in the extractant system is 65%. The aqueous phase and the organic phase are respectively sent to the aqueous phase inlet and the organic phase inlet of the impinging flow coupled ultrasonic reactor 1, and two jets are generated through the nozzle to collide and mix and extract, forming violent collision, shearing, extrusion and stretching. At the same time, the ultrasonic generator 2 applies ultrasonic waves with a frequency of 100 kHz to generate strong Micro jets and shock waves are used to achieve mixing at the microscopic and macroscopic levels. The temperature of the mixed extraction is 25° C., the reaction time is 60 min, the maximum speed of the liquid nozzles of the aqueous phase and the organic phase are both 9 m / s, and the flow rates of the aqueous phase and the organic phase are both 25 L / h. The mixture is then allowed to stand for 1.5 h, after which the feed liquid enters the liquid separation device 3 through the bottom outlet of the impact flow coupled ultrasonic reactor 1 for liquid separation to obtain purified phosphoric acid and a loaded extractant, wherein 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 was regenerated for 25 minutes to obtain a regenerated extractant which was reused in the mixed extraction process. The stripping agent used for the regeneration was 0.5 mol / L dilute hydrochloric acid.

[0052] Example 2

[0053] This embodiment provides a method for enhanced mixed extraction of impurities in wet-process phosphoric acid by impinging flow coupled with ultrasonic waves. The method is performed in a device system provided with an impinging flow coupled with ultrasonic reactor. The device system is the same as that in Embodiment 1. The method comprises the following steps:

[0054] The aqueous phase is made of wet-process phosphoric acid (same as in Example 1), the extractant system is made of trialkylphosphine oxide as the extractant, and kerosene as the diluent as the organic phase. The aqueous phase and the organic phase are respectively fed into the aqueous phase inlet and the organic phase inlet of the impinging stream coupled ultrasonic reactor, and two jets are generated through the nozzle to collide and perform mixed extraction, forming violent collision, shearing, extrusion and stretching. At the same time, the ultrasonic generator applies ultrasonic waves with a frequency of 60kHz to generate strong microjets and shock waves to achieve mixing at the microscopic and macroscopic levels. The temperature of the mixed extraction is 80°C, the reaction time is 20min, the mass concentration of the extractant in the extractant system is 65%, the maximum speed of the liquid nozzles of the aqueous phase and the organic phase is 8m / s, and the flow rate of the aqueous phase and the organic phase is 8L / h. Then, the mixture is allowed to stand for 1h, and then the feed liquid enters the liquid separation device through the bottom outlet of the impinging stream coupled ultrasonic reactor for liquid separation to obtain purified phosphoric acid and loaded extractant, wherein the loaded extractant is collected to the loaded extractant collection device through the upper organic phase outlet, and the purified phosphoric acid is collected to the purified phosphoric acid collection device through the bottom aqueous phase outlet;

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

[0056] Example 3

[0057] This embodiment provides a method for enhanced mixed extraction of impurities in wet-process phosphoric acid by impinging flow coupled with ultrasonic waves. The method is performed in a device system provided with an impinging flow coupled with ultrasonic reactor. The device system is the same as that in Embodiment 1. The method comprises the following steps:

[0058] The aqueous phase is made of wet-process phosphoric acid (same as in Example 1), the extractant system is made of 2-ethylhexyl phosphate mono-2-ethylhexyl ester as the extractant, and cyclohexane as the diluent as the organic phase. The aqueous phase and the organic phase are respectively fed into the aqueous phase inlet and the organic phase inlet of the impinging flow coupled ultrasonic reactor, and two jets are generated by the nozzle to collide and perform mixed extraction, forming violent collision, shearing, extrusion and stretching. At the same time, the ultrasonic generator applies ultrasonic waves with a frequency of 40 kHz to generate strong microjets and shock waves, thereby achieving mixing at the microscopic and macroscopic levels. The mixed extraction The temperature is 25° C., the reaction time is 10 min, the mass concentration of the extractant in the extractant system is 55%, the maximum liquid nozzle speeds of the aqueous phase and the organic phase are both 9 m / s, the flow rates of the aqueous phase and the organic phase are both 15 L / h, and then the mixture is allowed to stand for 2 hours, after which the feed liquid enters a liquid separation device through the bottom outlet of an impact flow coupled ultrasonic reactor for liquid separation to obtain purified phosphoric acid and a loaded extractant, wherein the loaded extractant is collected to the loaded extractant collection device through the upper organic phase outlet, and the purified phosphoric acid is collected to the purified phosphoric acid collection device through the bottom aqueous phase outlet;

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

[0060] Example 4

[0061] This embodiment provides a method for enhanced mixed extraction of impurities in wet-process phosphoric acid by impinging flow coupled with ultrasonic waves. The method is performed in a device system provided with an impinging flow coupled with ultrasonic reactor. The device system is the same as that in Embodiment 1. The method comprises the following steps:

[0062] The aqueous phase is made of wet-process phosphoric acid (the same as in Example 1), the extractant system consisting of 2-ethylhexyl phosphate mono-2-ethylhexyl ester as the extractant and butyl acetate as the diluent as the organic phase. The aqueous phase and the organic phase are respectively fed into the aqueous phase inlet and the organic phase inlet of the impinging flow coupled ultrasonic reactor, and two jets are generated by a nozzle to collide and mix and extract, forming violent collision, shearing, extrusion and stretching. At the same time, an ultrasonic generator applies ultrasonic waves with a frequency of 100 kHz to generate strong microjets and shock waves, thereby achieving mixing at the microscopic and macroscopic levels. The mixing The temperature of the combined extraction is 80° C., the reaction time is 40 min, the mass concentration of the extractant in the extractant system is 10%, the maximum speed of the liquid nozzles of the aqueous phase and the organic phase is 1 m / s, the flow rates of the aqueous phase and the organic phase are 5 L / h, and then the mixture is allowed to stand for 2 hours, after which the feed liquid enters a liquid separation device through the bottom outlet of the impinging flow coupled ultrasonic reactor for liquid separation to obtain purified phosphoric acid and a loaded extractant, wherein the loaded extractant is collected to the loaded extractant collection device through the upper organic phase outlet, and the purified phosphoric acid is collected to the purified phosphoric acid collection device through the bottom aqueous phase outlet;

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

[0064] Example 5

[0065] This embodiment provides a method for enhanced mixed extraction of impurities in wet-process phosphoric acid by impinging flow coupled with ultrasonic waves. The method is performed in a device system provided with an impinging flow coupled with ultrasonic reactor. The device system is the same as that in Embodiment 1. The method comprises the following steps:

[0066] The aqueous phase is made of wet-process phosphoric acid (same as in Example 1), dimethylheptyl methylphosphonate is made of an extractant, and kerosene is made of a diluent to form an extractant system organic phase. The aqueous phase and the organic phase are respectively fed into the aqueous phase inlet and the organic phase inlet of an impinging stream coupled ultrasonic reactor, and two jets are generated through a nozzle to collide and perform mixed extraction, thereby forming violent collision, shearing, extrusion and stretching. At the same time, an ultrasonic generator applies ultrasonic waves with a frequency of 20 kHz to generate strong microjets and shock waves to achieve mixing at the microscopic and macroscopic levels. The temperature of the mixed extraction is 25° C., the reaction time is 10 min, the mass concentration of the extractant in the extractant system is 30%, the maximum speed of the liquid nozzles of the aqueous phase and the organic phase is 10 m / s, and the flow rates of the aqueous phase and the organic phase are 5 L / h. The mixture is then allowed to stand for 1 h, and then the feed liquid enters a liquid separation device through the bottom outlet of the impinging stream coupled ultrasonic reactor for liquid separation to obtain purified phosphoric acid and a loaded extractant, wherein the loaded extractant is collected to the loaded extractant collecting device through the upper organic phase outlet, and the purified phosphoric acid is collected to the purified phosphoric acid collecting device through the bottom aqueous phase outlet;

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

[0068] Example 6

[0069] This embodiment provides a method for enhanced mixed extraction of impurities in wet-process phosphoric acid by impinging flow coupled with ultrasonic waves. The method is performed in a device system provided with an impinging flow coupled with ultrasonic reactor. The device system is the same as that in Embodiment 1. The method comprises the following steps:

[0070] The aqueous phase is wet-process phosphoric acid (same as in Example 1), the extractant system consisting of dimethylheptyl methylphosphonate as the extractant and n-hexane as the diluent as the organic phase, the aqueous phase and the organic phase are respectively fed into the aqueous phase inlet and the organic phase inlet of the impinging stream coupled ultrasonic reactor, two jets are generated through the nozzle for collision and mixed extraction, forming violent collision, shearing, extrusion and stretching, and at the same time, the ultrasonic generator applies ultrasonic waves with a frequency of 80kHz to generate strong microjets and shock waves to achieve mixing at the microscopic and macroscopic levels, the temperature of the mixed extraction is 80°C, the reaction time is 60min, the mass concentration of the extractant in the extractant system is 5%, the maximum speed of the liquid nozzles of the aqueous phase and the organic phase is 7m / s, the flow rate of the aqueous phase and the organic phase is 6L / h, and then the mixture is allowed to stand for 2h, after which the feed liquid enters the liquid separation device through the bottom outlet of the impinging stream coupled ultrasonic reactor for liquid separation to obtain purified phosphoric acid and loaded extractant, wherein the loaded extractant is collected to the loaded extractant collecting device through the upper organic phase outlet, and the purified phosphoric acid is collected to the purified phosphoric acid collecting device through the bottom aqueous phase outlet;

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

[0072] Example 7

[0073] This embodiment provides a method for enhanced mixed extraction of impurities in wet-process phosphoric acid by impinging flow coupled with ultrasonic waves. The method is different from that in Embodiment 1 only in that the frequency of the ultrasonic waves is 15 kHz.

[0074] Example 8

[0075] This embodiment provides a method for enhanced mixed extraction of impurities in wet-process phosphoric acid by impinging flow coupled with ultrasonic waves. The difference between the method and embodiment 1 is that the frequency of the ultrasonic waves is 120 kHz.

[0076] Example 9

[0077] This embodiment provides a method for the mixed extraction of impurities in wet-process phosphoric acid by impinging flow coupled with ultrasonic wave enhancement. The difference between the method and the embodiment 1 is that the maximum velocity of the liquid nozzles of the aqueous phase and the organic phase are both 0.3 m / s.

[0078] Example 10

[0079] This embodiment provides a method for the mixed extraction of impurities in wet-process phosphoric acid by impinging flow coupled with ultrasonic wave enhancement. The difference between the method and the embodiment 1 is that the maximum velocity of the liquid nozzles of the aqueous phase and the organic phase are both 15 m / s.

[0080] Comparative Example 1

[0081] This comparative example provides a method for enhanced mixed extraction of impurities in wet-process phosphoric acid by impinging flow coupled ultrasonic wave. The only difference compared with Example 1 is that the impinging flow coupled ultrasonic reactor is replaced by a stirred reactor, that is, the mixed extraction process is carried out in a stirred reactor, and the stirring rate is controlled to be 200r / min.

[0082] The Fe content in the purified phosphoric acid obtained in Examples 1-10 and Comparative Example 1 was 3+ and Al 3+ The mass percentage content was determined by 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] From the contents of Table 1, we can see the following points:

[0086] (1) From the data of Examples 1-6, it can be seen that, taking the removal of impurities such as Fe and Al in wet-process phosphoric acid as an example, the method provided by the present invention can enhance the mixed extraction process by coupling the impinging flow with the ultrasonic wave, and can remove Fe and Al impurities in wet-process phosphoric acid under optimal conditions. 3+ The extraction rate of Al 3+ The extraction rate of Fe 3+ The extraction rate of Al 3+ The extraction rate reaches over 90%.

[0087] (2) A comprehensive comparison of the data of Example 1 and Examples 7-8 shows that the only difference between Examples 7-8 and Example 1 is that the frequency of the ultrasonic wave is not within the preferred range of the present invention. The frequency of the ultrasonic wave in Example 7 is too small, resulting in limited enhancement effect on the mixed extraction process, while the frequency of the ultrasonic wave in Example 8 is too large, although it has little effect on the extraction rate, it leads to increased energy consumption. It can be seen that the present invention can further improve the mixed extraction effect while reducing energy consumption by optimally controlling the frequency of the ultrasonic wave.

[0088] (3) Comprehensive comparison of the data of Example 1 and Examples 9-10 shows that the only difference between Example 9-10 and Example 1 is that the maximum liquid nozzle speeds of the aqueous phase and the organic phase are not within the preferred range of the present invention. 3+ and Al 3+ The extraction rate is significantly reduced. It can be seen that the present invention can enhance the mixing and mass transfer between the fluids and ensure the contact time between the aqueous phase and the organic phase by preferentially controlling the maximum velocity of the liquid nozzles of the aqueous phase and the organic phase, thereby further improving the mixed extraction effect.

[0089] (4) Comprehensively 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 stream coupled with ultrasonic wave is not used for intensification, and the extraction is performed 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-process phosphoric acid by using impinging stream coupled with ultrasonic wave to intensify the mixed extraction process.

[0090] In summary, the present invention uses the impinging flow coupled ultrasonic method to strengthen the extraction process, which 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 the wet-process phosphoric acid.

[0091] The applicant declares that the above is only a specific implementation mode 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 thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for extracting impurities from wet-process phosphoric acid by impinging flow coupled with ultrasonic enhanced mixing. It is characterized in that The method comprises the following steps: With wet-process phosphoric acid as the aqueous phase and the extractant system as the organic phase, the aqueous phase and the organic phase are respectively formed into two jets for collision and mixed extraction, and ultrasonic waves are applied to enhance the mixed extraction process of the aqueous phase and the organic phase, and then the liquids are separated to obtain purified phosphoric acid and a loaded extractant.

2. The method according to claim 1, It is characterized in that The extractant used in the extractant system includes any one or a combination of at least two of trialkylphosphine oxide, tributyl phosphate, di(2,4,4-trimethylpentyl) hypophosphorous acid, dimethylheptyl methylphosphonate, di(2-ethyl-hexyl) phosphate, 2-ethylhexyl phosphate mono-2-ethylhexyl ester, ethyl acetate, amyl acetate, methyl isobutyl ketone, cyclohexanone, isopentanol, trialkylmethylamine, didecylamine or trioctylamine; Preferably, the mass concentration of the extractant in the extractant system is 5-65%.

3. The method according to claim 1 or 2, It is characterized in that The reaction time of the mixed extraction is 1-60min; Preferably, the temperature of the mixed extraction is 20-90°C.

4. The method according to any one of claims 1 to 3, It is characterized in that The mixed extraction is followed by standing still; Preferably, the standing time is 1-2 hours.

5. The method according to any one of claims 1 to 4, It is characterized in that The wet-process phosphoric acid includes the wet-process phosphoric acid obtained by decomposing phosphate rock powder with acid solution and then separating and purifying in sequence; Preferably, the wet-process phosphoric acid contains 10-40% P by mass. 2 O 5 , 0.1-1.2% Fe, 0.3-3.5% Al.

6. The method according to any one of claims 1 to 5, It is characterized in that The maximum liquid nozzle speeds of the aqueous phase and the organic phase are independently 0.5-10 m / s; Preferably, the flow rates of the aqueous phase and the organic phase in the reactor are independently 5-25 L / h.

7. The method according to any one of claims 1 to 6, It is characterized in that The frequency of the ultrasonic wave in the mixed extraction is 20-100 kHz.

8. The method according to any one of claims 1 to 7, It is characterized in that The loaded extractant is regenerated to obtain a regenerated extractant which is reused in the mixed extraction process; Preferably, the stripping agent used for the regeneration includes any one of dilute hydrochloric acid, dilute nitric acid, ammonium oxalate or water; Preferably, the concentrations of the dilute hydrochloric acid, dilute nitric acid and ammonium oxalate are each independently 0.1-1 mol / L; Preferably, the regeneration time is 10-30 min.

9. The method according to any one of claims 1 to 8, It is characterized in that The mixed extraction process is carried out in an impinging stream coupled ultrasonic reactor; Preferably, the impinging flow coupled ultrasonic reactor comprises an organic phase inlet and an aqueous phase inlet; Preferably, the organic phase inlet and the aqueous phase inlet are respectively provided with nozzles; Preferably, an ultrasonic generator is arranged at the bottom of the impinging flow coupled ultrasonic reactor; Preferably, the bottom outlet of the impinging flow coupled ultrasonic reactor is connected to a liquid separation device; Preferably, the upper organic phase outlet of the liquid separation device is connected to a loaded extractant collecting device; Preferably, the bottom aqueous phase outlet of the liquid separation device is connected to a purified phosphoric acid collection device.

10. The method according to any one of claims 1 to 9, It is characterized in that The method comprises the following steps: The invention adopts wet-process phosphoric acid as an aqueous phase and an extractant system as an organic phase. The extractant used in the extractant system includes any one of trialkylphosphine oxide, tributyl phosphate, di(2,4,4-trimethylpentyl) hypophosphorous acid, dimethylheptyl methylphosphonate, di(2-ethyl-hexyl) phosphate, 2-ethylhexyl phosphate mono-2-ethylhexyl ester, ethyl acetate, amyl acetate, methyl isobutyl ketone, cyclohexanone, isopentanol, trialkylmethylamine, didecylamine or trioctylamine, or a combination of at least two thereof. The mass concentration of the extractant in the extractant system is 5-65%. The aqueous phase and the organic phase are mixed. The phases are formed into two jets to collide and undergo mixed extraction, the maximum speed of the liquid nozzles of the aqueous phase and the organic phase are independently 0.5-10 m / s, the flow rates of the aqueous phase and the organic phase in the reactor are 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° C., and 20-100 kHz ultrasonic waves are applied to strengthen the mixed extraction process of the aqueous phase and the organic phase, and then the mixture is allowed to stand for 1-2 hours, and then the liquids are separated to obtain purified phosphoric acid and a loaded extractant; The loaded extractant is regenerated for 10-30 minutes to obtain a regenerated extractant which is reused in the mixed extraction process. The stripping agent used for the regeneration includes any one of dilute hydrochloric acid, dilute nitric acid, ammonium oxalate or water. The concentrations of the dilute hydrochloric acid, dilute nitric acid and ammonium oxalate are independently 0.1-1 mol / L.

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