Enhanced extraction separation system for wet-process phosphoric acid

Abstract

An enhanced extraction separation system for wet-process phosphoric acid comprises a liquid membrane extraction device and an enhanced phase separation device which are connected in sequence, the liquid membrane extraction device is provided with a phosphoric acid liquid inlet and an extraction agent inlet, and the liquid membrane extraction device is used for enabling a mixed material of phosphoric acid liquid and an extraction agent to continuously form a liquid membrane, liquid filaments and liquid drops; the liquid membrane extraction effect is achieved; the reinforced phase separation device is used for rapidly separating the mixed liquid discharged from the liquid membrane extraction device and comprises a fiber multiplication section and a settling section which are sequentially arranged in the flowing direction of the mixed liquid, the fiber multiplication section promotes liquid drop growth and separation of the extraction liquid, and the settling section separates the extraction liquid. The liquid membrane extraction and reinforced phase separator technology is reasonably applied to the wet-process phosphoric acid extraction working condition, and good extraction and separation effects are achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of extraction and separation, in particular to an enhanced extraction and separation system for wet-process phosphoric acid. Background Art

[0002] There are two main methods for producing phosphoric acid: one is the wet method and the other is the thermal method. The wet method uses inorganic acid to decompose phosphate ore to prepare phosphoric acid, but wet phosphoric acid is affected by the characteristics of raw materials and processes, and the impurity content in wet phosphoric acid is relatively high. Compared with the wet method, the phosphoric acid produced by the thermal method has a higher purity, but due to the influence of mineral sources and environmental protection policies, the production capacity of thermal phosphoric acid has always been limited and cannot meet market demand. Especially in recent years, with the vigorous development of lithium iron phosphate batteries, the market demand for high-purity phosphoric acid has increased dramatically, resulting in a shortage of high-purity phosphoric acid in the market. In order to meet market demand, wet phosphoric acid manufacturers have to seek new methods to improve the purity of wet phosphoric acid products.

[0003] At present, the purity of wet phosphoric acid is improved mainly by optimizing the extraction process and post-treatment process. At present, the main method used for wet phosphoric acid extraction is to extract with a plate extraction tower and then separate and purify phosphoric acid in a sedimentation tank. The problems with this type of process are: 1. The extraction selectivity is not high and the extraction efficiency is low, which not only causes the loss of phosphoric acid, but also leads to incomplete removal of impurity ions in phosphoric acid, affecting the final purity of phosphoric acid. 2. The sedimentation separation time is long, resulting in waste of land resources and poor continuity. 3. Incomplete sedimentation separation leads to phosphoric acid in the extractant and extractant in phosphoric acid, resulting in the loss of phosphoric acid and extractant; and the extractant entering the phosphoric acid will also affect the final purity of the phosphoric acid.

[0004] Alternatively, an integrated phosphoric acid extraction device is used, such as Figure 1 , the extractant enters the extraction tower from the lower part of the extraction tower 10, and the phosphoric acid enters the extraction tower from the upper part of the extraction tower 10. The extractant and the phosphoric acid are in countercurrent contact on the tower plate 11 to achieve full contact between the extractant and the phosphoric acid. The extractant has a low density and moves upward. After settling for 1 to 2 hours in the upper settling section 12, it is discharged from the extraction tower. The upper part is the extraction phase (the extraction phase contains 600 to 2000 mg / L of phosphoric acid); the phosphoric acid has a high density and moves downward. After settling for 1 to 2 hours in the lower settling section 13, it is discharged from the extraction tower. The lower part is the raffinate phase (the raffinate phase contains 600 to 1000 mg / L of extractant); the extraction and separation efficiency of this process is low and the product quality is poor. Utility Model Content

[0005] In view of the above technical problems, the purpose of the utility model is to provide an enhanced extraction and separation system for wet-process phosphoric acid, which rationally applies liquid membrane extraction and enhanced phase separator technology to wet-process phosphoric acid extraction conditions, and achieves good extraction and separation effects.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0007] An enhanced extraction and separation system for wet-process phosphoric acid,

[0008] It includes a liquid membrane extraction device and an enhanced phase separation device connected in sequence,

[0009] The liquid membrane extraction device has a phosphoric acid liquid inlet and an extractant inlet, and is used to continuously form a liquid membrane, liquid filaments and liquid droplets from a mixture of the phosphoric acid liquid and the extractant to achieve a liquid membrane extraction effect;

[0010] The enhanced phase separation device is used to quickly separate the mixed liquid from the liquid membrane extraction device, and includes a fiber multiplication section and a sedimentation section arranged in sequence along the flow direction of the mixed liquid. The fiber multiplication section promotes the growth and separation of droplets of the extract, and the sedimentation section separates the extract.

[0011] In some technical schemes, the liquid membrane extraction device is provided with a feeding unit, which includes a phosphoric acid liquid inlet pipe and an extractant inlet pipe. The phosphoric acid liquid inlet pipe passes through the phosphoric acid liquid inlet and a first nozzle is arranged at the outlet end. The extractant inlet pipe passes through the extractant inlet and a second nozzle is arranged at the outlet end. The first nozzle and the second nozzle are arranged opposite to each other.

[0012] In some technical solutions, the liquid membrane extraction device is further provided with an extraction unit, and the extraction unit includes a rotating filler and a rotating shaft. The rotating filler is arranged around the outside of the feeding unit, and the rotating shaft is concentrically connected to the rotating filler and driven to rotate by an external driving device.

[0013] In some technical solutions, the rotating filler is a loose fiber bed.

[0014] In some technical solutions, the fiber multiplication section selects a loose fiber bed or a dense fiber bed according to the actual situation of whether the material contains solid particles.

[0015] In some technical solutions, the enhanced phase separation device has a mixed liquid inlet and an extract liquid outlet and a raffinate outlet, the mixed liquid inlet is connected to the fiber multiplication section, and the extract liquid outlet and the raffinate outlet are connected to the sedimentation section.

[0016] In some technical solutions, the mixed liquid inlet is connected to a mixed liquid inlet pipe, and the outlet end of the mixed liquid inlet pipe is connected to a distributor, and the distributor evenly distributes the mixed liquid to the entire flow cross-section of the fiber multiplication section.

[0017] In some technical solutions, the enhanced phase separation device has a horizontal space and a vertical space, the fiber multiplication section is arranged in the horizontal space, the sedimentation section is arranged in the vertical space, and the vertical height of the vertical space is greater than the longitudinal height of the horizontal space.

[0018] In some technical solutions, a pipeline pump is arranged on the connecting pipeline between the liquid membrane extraction device and the enhanced phase separation device.

[0019] In some technical solutions, an exhaust port is provided on the top wall of the shell of the liquid membrane extraction device.

[0020] The utility model adopts the above technical solution to have at least the following beneficial effects:

[0021] 1. The utility model provides an enhanced extraction and separation system for wet-process phosphoric acid, which reasonably applies liquid membrane extraction and enhanced phase separator technology to wet-process phosphoric acid extraction conditions, and achieves good extraction and separation effects; compared with traditional extraction and separation technology, it has strong continuity, small device footprint (saves more than 50% of floor space), high extraction efficiency, high separation efficiency, saves extraction agent consumption, high yield (phosphoric acid yield increases by more than 3%, and extraction agent yield increases by more than 0.5%), and improves product quality, which greatly improves the competitiveness of phosphoric acid enterprises in the industry;

[0022] 2. The utility model provides an enhanced extraction and separation system for wet-process phosphoric acid, wherein a liquid membrane extraction device is provided with a feed unit and an extraction unit respectively, and the feed unit sprays phosphoric acid liquid and an extractant through nozzles arranged opposite to each other to achieve a droplet extraction degree; the mixed liquid is rotated and cut into fine droplets by an outer extraction unit to finally form a liquid membrane, so that the second full contact mixing of the mixed liquid is achieved to achieve a liquid membrane extraction degree; thereby, the extraction efficiency is improved, the extraction is more thorough, and the product quality is higher;

[0023] 3. The utility model provides an enhanced extraction and separation system for wet-process phosphoric acid, wherein a distributor, a fiber multiplication section and a sedimentation section are sequentially arranged inside the enhanced phase separation device along the liquid flow direction. The distributor evenly distributes the liquid flow to the entire flow cross-section of the fiber multiplication section. Small droplets are adsorbed and collided on the surface of a dense fiber filter element, gradually grow, and leave the dense fiber filter element after growing to a certain extent, and complete separation is achieved in the sedimentation section; thereby, the separation efficiency is higher, the consumption of the extractant is saved, and the product quality is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings and their marks required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 It is a structural schematic diagram of the integrated phosphoric acid extraction device described in the background technology;

[0026] Figure 2 It is a schematic structural diagram of the enhanced extraction and separation system described in an embodiment of the utility model.

[0027] The meanings of the symbols in the figure are as follows:

[0028] 10—extraction tower, 11—tower plate, 12—upper settling section, 13—lower settling section;

[0029] 20—liquid membrane extraction device, 21—rotating filler, 22—rotating shaft;

[0030] 31—fiber multiplication section, 32—sedimentation section. DETAILED DESCRIPTION

[0031] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the specific implementation methods of the utility model will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0032] In order to simplify the drawings, only the parts related to the utility model are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0033] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0034] In this article, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0035] Example 1

[0036] like Figure 2The present embodiment provides an enhanced extraction and separation system for wet-process phosphoric acid, comprising a liquid membrane extraction device 20 and an enhanced phase separation device connected in sequence, wherein the liquid membrane extraction device 20 has a phosphoric acid liquid inlet and an extractant inlet, and is used to continuously form a liquid membrane, liquid filaments and liquid droplets from a mixture of phosphoric acid liquid and the extractant to achieve a liquid membrane extraction effect; the enhanced phase separation device is used to quickly separate the mixed liquid from the liquid membrane extraction device 20, and comprises a fiber multiplication section 31 and a sedimentation section 32 arranged in sequence along the flow direction of the mixed liquid, wherein the fiber multiplication section 31 promotes the growth and separation of liquid droplets of the extract, and the sedimentation section 32 separates the extract.

[0037] In the above embodiment, the liquid membrane extraction device 20 is provided with an extraction unit, which includes a rotating filler 21 and a rotating shaft 22. The rotating shaft 22 is concentrically connected to the rotating filler 21 and is driven to rotate by an external driving device; the rotating filler 21 is preferably a loose fiber bed, but it can also be, for example, a stainless steel wire mesh, a stainless steel corrugated plate, or a catalyst-loaded filler.

[0038] Specifically, the loose fiber bed is woven from extremely fine fiber materials, and the loose fiber bed is connected to the rotating shaft 22 as a whole, and is driven by a motor to rotate at high speed. When the mixed material contacts the high-speed rotating loose fiber bed, it is instantly torn into extremely thin liquid films, liquid filaments and liquid droplets, generating a huge phase contact area, so that the two phases are evenly and fully mixed; at the same time, the renewal rate of the formed liquid film, liquid filaments and liquid droplets will also be greatly improved, and the transfer process and microscopic mixing process of the two phases are greatly enhanced, thereby achieving efficient extraction (reaching the level of liquid film extraction).

[0039] In the above embodiment, the fiber multiplication section 31 is preferably a dense fiber filter element, and the dense fiber bed can be adjusted to a loose fiber bed according to the actual situation of whether the material contains fine solid particles.

[0040] In the process of the mixed liquid from the liquid membrane extraction device 20 passing through the dense fiber filter element, the small droplets of the extractant are constantly adsorbed and collided on the surface of the dense fiber filter element, gradually growing, and leaving the dense fiber filter element after growing to a certain extent, and are completely separated in the sedimentation section 32.

[0041] In the above embodiment, if the height difference between the liquid membrane extraction device 20 and the enhanced phase separation device is less than 4 meters, it is necessary to add a pipeline pump between the liquid membrane extraction device 20 and the enhanced phase separation device; the pressure difference between the devices is usually controlled to be less than 20KPa.

[0042] In the above embodiment, an exhaust port is provided on the top wall of the shell of the liquid membrane extraction device 20 .

[0043] This application rationally applies liquid membrane extraction and enhanced phase separator technology to phosphoric acid extraction conditions, achieving good extraction and separation effects:

[0044] The extraction unit of the liquid membrane extraction device 20 is used to rotate and cut the mixed material into fine droplets to finally form a liquid membrane, so that the mixed liquid is fully contacted and mixed to achieve the degree of liquid membrane extraction; thereby, the extraction efficiency is improved, the extraction is more thorough, and the product quality is higher;

[0045] By sequentially arranging the fiber multiplication section 31 and the sedimentation section 32 along the liquid flow direction inside the enhanced phase separation device, the small droplets are adsorbed and collided on the surface of the dense fiber filter element, gradually grow, and leave the dense fiber filter element after growing to a certain extent, and achieve complete separation in the sedimentation section 32; thereby, the separation efficiency is higher, the consumption of the extractant is saved, and the product quality is improved;

[0046] Compared with traditional extraction and separation technology, it has strong continuity, small footprint (saves more than 50% of floor space), high extraction efficiency, high separation efficiency, saves extraction agent consumption, high yield (phosphoric acid yield increased by more than 3%, extraction agent yield increased by more than 0.5%), and improves product quality, greatly improving the competitiveness of bio-based fermentation broth enterprises in the industry;

[0047] The content of extractant in phosphoric acid after separation by the scheme of the present application is less than 200 mg / L (undissolved extractant is less than 20 mg / L), and the content of phosphoric acid in the extractant is less than 200 mg / L (undissolved phosphoric acid is less than 20 mg / L).

[0048] Example 2

[0049] like Figure 2 Based on the solution of Example 1, this embodiment makes the following improvements:

[0050] The above-mentioned liquid membrane extraction device 20 is provided with a feeding unit, which includes a phosphoric acid liquid inlet pipe and an extractant inlet pipe. The phosphoric acid liquid inlet pipe runs through the phosphoric acid liquid inlet and a first nozzle is arranged at the outlet end. The extractant inlet pipe runs through the extractant inlet and a second nozzle is arranged at the outlet end. The first nozzle and the second nozzle are arranged opposite to each other.

[0051] In this embodiment, the feeding unit sprays the phosphoric acid liquid and the extractant against each other through nozzles arranged opposite to each other to achieve droplet extraction; the mixed liquid is then rotated and cut into fine droplets by the outer extraction unit to finally form a liquid film, thereby achieving a second full contact mixing of the mixed liquid to achieve liquid film extraction; thereby, the extraction efficiency is improved, the extraction is more thorough, and the product quality is higher.

[0052] Example 3

[0053] This embodiment is based on the solution of embodiment 1, and makes the following improvements:

[0054] The enhanced phase separation device has a mixed liquid inlet and an extract liquid outlet and a raffinate outlet, the mixed liquid inlet is connected to the fiber multiplication section 31, and the extract liquid outlet and the raffinate outlet are connected to the sedimentation section 32.

[0055] The mixed liquid inlet is connected to a mixed liquid inlet pipe, and the outlet end of the mixed liquid inlet pipe is connected to a distributor, which evenly distributes the mixed liquid to the entire flow cross-section of the fiber multiplication section 31 .

[0056] In this embodiment, the uniform distribution of the liquid by the distributor helps to improve the droplet multiplication and separation effects of the dense fiber filter element, resulting in higher separation efficiency and improved product quality.

[0057] Example 4

[0058] like Figure 2 Based on the solutions of Example 1 and Example 3, this embodiment makes the following improvements:

[0059] The enhanced phase separation device has a horizontal space and a vertical space. The fiber multiplication section 31 is arranged in the horizontal space, and the sedimentation section 32 is arranged in the vertical space. The vertical height of the vertical space is greater than the longitudinal height of the horizontal space.

[0060] Specifically, the enhanced phase separation device is T-shaped as a whole, the mixed liquid inlet is arranged on the top side of the horizontal space, the fiber multiplication section 31 is vertically arranged in the horizontal space, the vertical space is connected to the horizontal space and is located at the bottom side thereof; or, the enhanced phase separation device is T-shaped as a whole The mixed liquid inlet is arranged on the left side of the horizontal space, the fiber multiplication section 31 is arranged horizontally in the horizontal space, and the vertical space is connected to the horizontal space and is located on the right side thereof; of course, according to different input directions of the mixed liquid, the symmetrical configuration of the above enhanced phase separation device can also be implemented.

[0061] This embodiment can significantly improve the sedimentation and separation efficiency of the mixed liquid by designing the sedimentation section 32 with a relatively higher height; at the same time, the space occupied by the fiber multiplication section 31 makes the device more compact and the implementation effect of droplet multiplication is more excellent.

[0062] Example 5

[0063] This embodiment provides a process mechanism description based on the schemes of embodiments 1-4:

[0064] The enhanced extraction and separation system is a combination of a liquid membrane extraction device 20 and an enhanced phase separation device. Phosphoric acid and an extractant enter the liquid membrane extraction device 20 through an extractant inlet and a phosphoric acid liquid inlet. Phosphoric acid and an extractant are first sprayed and mixed through a first nozzle and a second nozzle respectively. The mixed liquid moves toward the loose fiber bed under the centrifugal force of the loose fiber bed driven by the rotating shaft 22. When the mixed liquid contacts the loose fiber bed, the mixed liquid is cut into fine droplets by the loose fiber bed and finally forms a liquid film, realizing the second full contact and mixing of the mixed liquid. The mixed liquid passing through the loose fiber bed is the mixed liquid of the extraction phase and the raffinate phase after the liquid membrane extraction. The mixed liquid enters the enhanced phase separation device through the lower part of the liquid membrane extraction device 20. When the mixed liquid passes through the dense fiber filter element, the extractant droplets continue to grow, and finally the extraction phase and the raffinate phase are quickly separated, and the separation time of the extraction phase and the raffinate phase is shortened to less than 30 minutes. The phosphoric acid content in the extraction phase is reduced to less than 200 mg / L, and the extractant content in the raffinate phase is reduced to less than 200 mg / L.

[0065] The above-mentioned embodiments only express several implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the utility model. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, and these all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model shall be based on the attached claims.

Claims

1. An enhanced extraction and separation system for wet-process phosphoric acid, characterized in that: It includes a liquid membrane extraction device and an enhanced phase separation device connected in sequence, The liquid membrane extraction device has a phosphoric acid liquid inlet and an extractant inlet, and is used to continuously form a liquid membrane, liquid filaments and liquid droplets from a mixture of the phosphoric acid liquid and the extractant to achieve a liquid membrane extraction effect; The enhanced phase separation device is used to quickly separate the mixed liquid from the liquid membrane extraction device, and includes a fiber multiplication section and a sedimentation section arranged in sequence along the flow direction of the mixed liquid. The fiber multiplication section promotes the growth and separation of droplets of the extract, and the sedimentation section separates the extract.

2. The enhanced extraction separation system according to claim 1, characterized in that: The liquid membrane extraction device is provided with a feed unit, which includes a phosphoric acid liquid inlet pipe and an extractant inlet pipe. The phosphoric acid liquid inlet pipe runs through the phosphoric acid liquid inlet and a first nozzle is arranged at the outlet end. The extractant inlet pipe runs through the extractant inlet and a second nozzle is arranged at the outlet end. The first nozzle and the second nozzle are arranged opposite to each other.

3. The enhanced extraction separation system according to claim 2, characterized in that: The liquid membrane extraction device is also provided with an extraction unit, which includes a rotating filler and a rotating shaft. The rotating filler is arranged around the outside of the feeding unit, and the rotating shaft is concentrically connected to the rotating filler and is driven to rotate by an external driving device.

4. The enhanced extraction separation system according to claim 3, characterized in that: The rotating packing is a loose fiber bed.

5. The enhanced extraction separation system according to claim 1, characterized in that: The fiber multiplication section selects a loose fiber bed or a dense fiber bed according to the actual situation of whether the material contains solid particles.

6. The enhanced extraction separation system according to claim 1, characterized in that: The enhanced phase separation device has a mixed liquid inlet and an extract liquid outlet and a raffinate outlet. The mixed liquid inlet is connected to the fiber multiplication section, and the extract liquid outlet and the raffinate outlet are connected to the sedimentation section.

7. The enhanced extraction separation system according to claim 6, characterized in that: The mixed liquid inlet is connected to a mixed liquid inlet pipe, and the outlet end of the mixed liquid inlet pipe is connected to a distributor, and the distributor evenly distributes the mixed liquid to the entire flow cross-section of the fiber multiplication section.

8. The enhanced extraction separation system according to claim 1, characterized in that: The enhanced phase separation device has a horizontal space and a vertical space. The fiber multiplication section is arranged in the horizontal space, and the sedimentation section is arranged in the vertical space. The vertical height of the vertical space is greater than the longitudinal height of the horizontal space.

9. The enhanced extraction separation system according to claim 1, characterized in that: A pipeline pump is arranged on the connecting pipeline between the liquid membrane extraction device and the enhanced phase separation device.

10. The enhanced extraction separation system according to claim 1, characterized in that: An exhaust port is arranged on the top wall of the shell of the liquid membrane extraction device.

Images