A method and device for extracting high-purity cesium sulfate from high-salt wastewater

Abstract

A method for extracting high-purity cesium sulfate from high-salinity wastewater relates to the technical field of wastewater treatment and recovery. The method first freezes the high-salinity wastewater to precipitate the sodium ions therein in the form of high-grade sodium sulfate, and reduces the sodium ion and sulfate ion content in the frozen liquid. Subsequently, the potassium ion crystals are precipitated through the first extraction and back extraction, and the back extraction liquid is evaporated for the first time. Finally, the evaporated liquid is subjected to secondary extraction, back extraction, and evaporation to obtain a high-grade cesium sulfate product. It is not only simple and convenient to operate, but also has low requirements on equipment and has good practical value. A device for extracting high-purity cesium sulfate from high-salinity wastewater, which is used in conjunction with the above method, and includes a refrigeration tank, a first extraction tank, a first evaporation tank, a second extraction tank, and a second evaporation tank connected in series in sequence. It is not only simple in structure and easy to use, but also has high processing efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment and recovery, and in particular to a device for extracting high-purity cesium sulfate from high-salt wastewater. Background Art

[0002] As an important scarce alkali metal resource, cesium is widely used in the fields of industrial catalysis, medicine and special glass. The existing methods for separating cesium mostly use distributed precipitation, fractional crystallization, ion exchange and solvent extraction, and solvent extraction is often used to obtain high-quality cesium. In the field of comprehensive recovery of solid hazardous waste, during the washing process of high-chlorine-containing materials, the salt-containing wastewater produced contains 0.5-1.5g / l cesium, 40-70g / l potassium, 90-100g / l sodium, 50-60g / l sulfate, and 130-160g / l chloride ions. The wastewater is extracted and stripped with TBP extractant, and the stripped liquid is evaporated and crystallized to recover the cesium-containing product. Due to the high ion concentration in the salt-containing wastewater, the extraction process is difficult to separate, and the potassium content makes it difficult to obtain a high-purity cesium product. In addition, the existing equipment for recovering cesium is relatively simple and cannot meet the recovery of high-purity cesium products. Summary of the invention

[0003] The first purpose of the present invention is to provide a method for extracting high-purity cesium sulfate from high-salt wastewater. The method is simple and convenient to operate, has low requirements on equipment, can effectively eliminate the interference of sodium and potassium ions in the high-salt wastewater, better extract and recover cesium ions, and obtain a high-purity cesium product.

[0004] The second purpose of the present invention is to provide a device for extracting high-purity cesium sulfate from high-salt wastewater, which has a simple structure and is easy to use. It can better cooperate with the above-mentioned method for extracting high-purity cesium sulfate from high-salt wastewater to achieve efficient recovery of cesium ions.

[0005] The embodiment of the present invention is achieved as follows:

[0006] A method for extracting high-purity cesium sulfate from high-salinity wastewater, comprising:

[0007] Freezing high-salinity wastewater to obtain sodium salt solid and post-freezing liquid;

[0008] The frozen liquid is sequentially extracted and stripped to obtain a first stripped liquid;

[0009] The liquid after the first stripping is evaporated and concentrated to obtain a concentrated liquid and a potassium salt solid;

[0010] Extracting and stripping the concentrated liquid once to obtain a second stripping liquid;

[0011] The second stripping solution is evaporated and concentrated to obtain cesium sulfate solid.

[0012] Furthermore, in other preferred embodiments of the present invention, the temperature for freezing high-salinity wastewater is -5~3°C.

[0013] Furthermore, in other preferred embodiments of the present invention, the frozen liquid / concentrated liquid is extracted and stripped by first mixing the frozen liquid / concentrated liquid with a pH regulator to adjust the pH value to alkaline, then mixing it with an extractant, and collecting the organic phase after standing and stratifying, and mixing it with a stripping agent; wherein the pH regulator is an aqueous solution of potassium hydroxide or sodium hydroxide, the extractant is TBP, and the stripping agent is an aqueous solution of sulfuric acid.

[0014] Furthermore, in other preferred embodiments of the present invention, after the frozen liquid / concentrated liquid is mixed with the pH adjuster, the pH value is 12-13.

[0015] Furthermore, in other preferred embodiments of the present invention, the phase ratio (O:A) is controlled to be 2-5:1 during the mixing process with the extractant; and the phase ratio (O:A) is controlled to be 4-8:1 during the mixing process with the stripping agent.

[0016] A device for extracting high-purity cesium sulfate from high-salinity wastewater comprises a refrigeration tank, a first extraction tank, a first evaporation tank, a second extraction tank and a second evaporation tank which are sequentially connected in series; the feed end of the refrigeration tank is connected to a feed pipeline, the discharge end of the refrigeration tank is connected to the feed end of the first extraction tank, the discharge end of the first extraction tank is connected to the feed end of the first evaporation tank, the discharge end of the first evaporation tank is connected to the feed end of the second extraction tank, and the discharge end of the second extraction tank is connected to the feed end of the second evaporation tank.

[0017] Furthermore, in other preferred embodiments of the present invention, a refrigeration jacket is provided on the outside of the refrigeration tank, and a refrigeration chamber for the refrigerant to pass through is formed between the refrigeration jacket and the outer wall of the refrigeration tank. The refrigeration chamber is provided with a refrigerant medium inlet and a refrigerant medium outlet. The refrigerant medium inlet is connected to the refrigerant medium supply device, and the refrigerant medium outlet is connected to the refrigerant medium recovery device.

[0018] Furthermore, in other preferred embodiments of the present invention, the discharge end of the refrigeration tank includes a first liquid phase outlet and a first solid phase outlet, the first liquid phase outlet is connected to the feed end of the first extraction tank, and the first solid phase outlet is connected to the first discharge pipe.

[0019] Furthermore, in other preferred embodiments of the present invention, the discharge end of the first extraction tank / the second extraction tank is connected to the waste liquid pipe and the liquid infusion pipe respectively through a three-way valve, and the liquid infusion pipe is connected to the feed end of the first evaporation tank / the second evaporation tank.

[0020] Furthermore, in other preferred embodiments of the present invention, a heating jacket is disposed on the outer side of the first evaporator / the second evaporator, a heating chamber for the passage of a heating medium is formed between the heating jacket and the outer wall of the first evaporator / the second evaporator, the heating chamber is provided with a heating medium inlet and a heating medium outlet, the heating medium inlet is communicated with a heating medium supply device, and the heating medium outlet is communicated with a heating medium recovery device.

[0021] Furthermore, in other preferred embodiments of the present invention, a gas phase outlet is provided on the top of the first evaporation tank / the second evaporation tank, and the gas phase outlet is communicated with the gas inlet end of the condenser.

[0022] Furthermore, in other preferred embodiments of the present invention, the discharge end of the first evaporation tank includes a second liquid phase outlet and a second solid phase outlet, the second liquid phase outlet is connected to the feed end of the first extraction tank, and the second solid phase outlet is connected to the second discharge pipe.

[0023] Furthermore, in other preferred embodiments of the present invention, the discharge end of the second evaporation tank includes a third liquid phase outlet and a third solid phase outlet, the third liquid phase outlet is connected to the feed end of the second extraction tank, and the third solid phase outlet is connected to the third discharge pipe.

[0024] Furthermore, in other preferred embodiments of the present invention, the equipment further comprises a pH adjusting agent storage tank, an extracting agent storage tank, and a stripping agent storage tank; the pH adjusting agent storage tank, the extracting agent storage tank, the stripping agent storage tank are connected to the first evaporation tank / the second evaporation tank.

[0025] Furthermore, in other preferred embodiments of the present invention, the device also includes a heat exchanger, the cold side inlet of the heat exchanger is connected to the discharge end of the refrigeration tank, and the cold side outlet is connected to the feed end of the first extraction tank; the hot side inlet of the heat exchanger is connected to the discharge end of the first evaporation tank, and the hot side outlet is connected to the feed end of the second extraction tank.

[0026] The beneficial effects of the embodiments of the present invention are:

[0027] The embodiment of the present invention provides a method for extracting high-purity cesium sulfate from high-salt wastewater, which is to first freeze the high-salt wastewater so that the sodium ions therein are precipitated in the form of high-grade sodium sulfate, and reduce the sodium ion and sulfate ion content in the frozen liquid. Subsequently, the potassium ions are crystallized and precipitated by the first extraction and stripping, and the stripping liquid is evaporated for the first time. Finally, the evaporated liquid is subjected to secondary extraction, stripping, and evaporation to obtain a high-grade cesium sulfate product. It is not only simple and convenient to operate, but also has low requirements for equipment and has good practical value. A device for extracting high-purity cesium sulfate from high-salt wastewater, the device is used in conjunction with the above method, including a refrigeration tank, a first extraction tank, a first evaporation tank, a second extraction tank, and a second evaporation tank connected in series in sequence. It is not only simple in structure and easy to use, but also has high processing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 A schematic diagram of the connection of a device for extracting high-purity cesium sulfate from high-salinity wastewater provided by the first embodiment of the present invention;

[0030] Figure 2 A connection diagram of a device for extracting high-purity cesium sulfate from high-salt wastewater provided in a second embodiment of the present invention.

[0031] Icons: 100-equipment; 110-refrigeration tank; 111-feed pipe; 112-first discharge pipe; 120-first extraction tank; 121-three-way valve; 122-waste liquid pipe; 123-infusion pipe; 130-first evaporation tank; 131-second discharge pipe; 140-second extraction tank; 150-second evaporation tank; 151-third discharge pipe; 161-pH adjuster storage tank; 162-extractant storage tank; 163-stripping agent storage tank; 200-equipment; 210-condenser; 220-heat exchanger. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device 100 or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0035] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0037] Example 1

[0038] This embodiment provides a device 100 for extracting high-purity cesium sulfate from high-salinity wastewater. Figure 1 As shown, it includes a refrigeration tank 110, a first extraction tank 120, a first evaporation tank 130, a second extraction tank 140 and a second evaporation tank 150 which are sequentially connected in series.

[0039] Among them, Figure 1As shown, the feed end of the refrigeration tank 110 is connected to the feed pipe 111, the discharge end of the refrigeration tank 110 is connected to the feed end of the first extraction tank 120, the discharge end of the first extraction tank 120 is connected to the feed end of the first evaporation tank 130, the discharge end of the first evaporation tank 130 is connected to the feed end of the second extraction tank 140, and the discharge end of the second extraction tank 140 is connected to the feed end of the second evaporation tank 150. When the device 100 treats high-salinity wastewater, the high-salinity wastewater is first added to the refrigeration tank 110 for freezing treatment, so that the sodium sulfate therein is crystallized and precipitated, thereby reducing the content of sodium ions and sulfate ions in the high-salinity wastewater. Subsequently, the high-salt wastewater after crystallization is introduced into the first extraction tank 120 for the first extraction and stripping, and the stripping liquid is transported to the first evaporation tank 130 for evaporation to crystallize potassium ions; the evaporated liquid is transported to the second extraction tank 140 for the second extraction and stripping, and the stripping liquid is transported to the second evaporation tank 150 for evaporation and concentration to obtain high-purity cesium sulfate.

[0040] Furthermore, a refrigeration jacket is provided on the outside of the refrigeration tank 110, and a refrigeration chamber for the passage of the refrigerant is formed between the refrigeration jacket and the outer wall of the refrigeration tank 110, and the refrigeration chamber is provided with a refrigerant medium inlet and a refrigerant medium outlet, and the refrigerant medium inlet is connected to a refrigerant medium supply device (not shown in the figure), and the refrigerant medium outlet is connected to a refrigerant medium recovery device (not shown in the figure). When in use, the refrigerant medium can be transported into the refrigeration chamber through the refrigerant medium supply device, and the refrigerant medium exchanges heat with the high-salt wastewater in the tank through the tank wall of the refrigeration tank 110 to achieve a refrigeration effect. Optionally, the refrigerant medium supply device and the refrigerant medium recovery device can be integrated into a circulating pump with a refrigeration function to achieve the recycling of the refrigerant medium.

[0041] like Figure 1 As shown, the discharge end of the refrigeration tank 110 includes a first liquid phase outlet and a first solid phase outlet, the first liquid phase outlet is connected to the feed end of the first extraction tank 120, and the first solid phase outlet is connected to the first discharge pipe 112. A filter is provided at the first liquid phase outlet to block the crystallized sodium sulfate solid and only allow the liquid phase to pass into the first extraction tank 120. The first solid phase outlet is used to recover high-quality sodium sulfate solid.

[0042] The discharge end of the first extraction tank 120 / the second extraction tank 140 is connected to the waste liquid pipe 122 and the liquid infusion pipe 123 respectively through the three-way valve 121, and the liquid infusion pipe 123 is connected to the feed end of the first evaporation tank 130 / the second evaporation tank 150. In the first extraction tank 120 / the second extraction tank 140, the incoming feed liquid is first mixed with the pH regulator (alkali solution) to adjust the pH of the feed liquid to alkalinity, and then mixed with the extractant, and allowed to stand to form an upper organic layer and a lower water layer. At this time, the waste liquid pipe 122 is opened to discharge the lower water layer, and the upper organic layer is retained. Subsequently, the stripping agent (acid solution) is added and mixed with the organic layer, and allowed to stand to form an upper organic layer and a lower water layer. The water layer is transported to the first evaporation tank 130 / the second evaporation tank 150 by the liquid infusion pipe 123, and the organic layer is discharged by the waste liquid pipe 122.

[0043] A heating jacket is provided on the outside of the first evaporation tank 130 / the second evaporation tank 150. A heating chamber for the passage of a heating medium is formed between the heating jacket and the outer wall of the first evaporation tank 130 / the second evaporation tank 150. The heating chamber is provided with a heating medium inlet and a heating medium outlet. The heating medium inlet is connected to a heating medium supply device (not shown), and the heating medium outlet is connected to a heating medium recovery device (not shown). When in use, the heating medium can be transported into the heating chamber through the heating medium supply device. The heating medium exchanges heat with the high-salt wastewater in the tank through the tank wall of the first evaporation tank 130 / the second evaporation tank 150 to achieve a heating effect. Optionally, the heating medium supply device and the heating medium recovery device can be integrated into a circulating pump with a heating function to achieve the recycling of the heating medium.

[0044] In addition, the refrigeration tank 110 , the first extraction tank 120 , the first evaporation tank 130 , the second extraction tank 140 , and the second evaporation tank 150 are all provided with stirring devices, which are driven by the motor on the top thereof to achieve a better mixing effect.

[0045] A gas phase outlet is disposed at the top of the first evaporation tank 130 / the second evaporation tank 150 , and the gas phase outlet is used to discharge the gas evaporated in the first evaporation tank 130 / the second evaporation tank 150 to achieve concentration of the feed liquid.

[0046] The discharge end of the first evaporation tank 130 includes a second liquid phase outlet and a second solid phase outlet, the second liquid phase outlet is connected to the feed end of the first extraction tank 120, and the second solid phase outlet is connected to the second discharge pipe 131. Similarly, a filter is provided at the second liquid phase outlet to intercept potassium salt crystals and only allow the liquid phase to enter the second extraction tank 140. The second solid phase outlet can be used to recover the generated potassium salt crystals.

[0047] Similarly, the discharge end of the second evaporation tank 150 includes a third liquid phase outlet and a third solid phase outlet, the third liquid phase outlet is connected to the feed end of the second extraction tank 140, and the third solid phase outlet is connected to the third discharge pipe 151. A filter is provided at the third liquid phase outlet to intercept the obtained cesium sulfate product and discharge some high-boiling liquid phases that have not evaporated. The third solid phase outlet can be used to recover the cesium sulfate product.

[0048] Furthermore, the device 100 further includes a pH adjusting agent storage tank 161, an extracting agent storage tank 162, and a stripping agent storage tank 163; the pH adjusting agent storage tank 161, the extracting agent storage tank 162, and the stripping agent storage tank 163 are connected to the first evaporation tank 130 / the second evaporation tank 150. The pH adjusting agent storage tank 161, the extracting agent storage tank 162, and the stripping agent storage tank 163 can be used for premixing, storing, and adding the pH adjusting agent, the extracting agent, and the stripping agent, respectively.

[0049] Example 2

[0050] This embodiment provides a device 200 for extracting high-purity cesium sulfate from high-salinity wastewater. Figure 2 As shown, it is basically the same as the device 100 of the first embodiment, including a refrigeration tank 110, a first extraction tank 120, a first evaporation tank 130, a second extraction tank 140 and a second evaporation tank 150 connected in series. The difference is that the device 200 of this embodiment further includes a condenser 210 and a heat exchanger 220.

[0051] Among them, Figure 2 As shown, the air inlet end of the condenser 210 is connected to the gas phase outlet at the top of the first evaporation tank 130 / the second evaporation tank 150. After the gas phase discharged from the top of the first evaporation tank 130 / the second evaporation tank 150 is condensed by the condenser 210, the moisture and organic matter therein are condensed, and the remaining gas is discharged into the atmosphere to avoid environmental pollution.

[0052] In addition, the cold side inlet of the heat exchanger 220 is connected to the discharge end of the refrigeration tank 110, and the cold side outlet is connected to the feed end of the first extraction tank 120; the hot side inlet of the heat exchanger 220 is connected to the discharge end of the first evaporation tank 130, and the hot side outlet is connected to the feed end of the second extraction tank 140. The feed liquid discharged from the refrigeration tank 110 and the first evaporation tank 130 is too low in temperature and too high in temperature, respectively, and is not suitable for direct extraction, which will lead to poor extraction effect. However, it will take too long to let it naturally reach room temperature. By setting up the heat exchanger 220, heat exchange can be carried out between the feed liquid discharged from the refrigeration tank 110 and the first evaporation tank 130, so that both can reach a temperature suitable for extraction without consuming other energy.

[0053] Example 3

[0054] This embodiment provides a method for extracting high-purity cesium sulfate from high-salinity wastewater, which comprises:

[0055] S1. Freeze the high-salt wastewater at -5~-3℃ to obtain sodium salt solid and frozen liquid;

[0056] S2. Mix the frozen liquid with a pH adjuster (sodium hydroxide solution) and stir until the pH value reaches 12 to 13;

[0057] S3. The pH-adjusted frozen liquid is mixed with the extractant (TBP) and stirred to control the phase ratio (O:A) to be 5:1, and the mixture is allowed to stand and separate into an upper organic phase and an aqueous phase;

[0058] S4. The first extracted liquid in S3 (the organic phase in S3) is mixed with the stripping agent (sulfuric acid solution) and stirred, and the phase ratio (O:A) is controlled to be 8:1, and the mixture is allowed to stand for stratification to obtain an upper organic phase and an aqueous phase;

[0059] S5. The first stripping liquid (aqueous phase in S4) in S4 is evaporated and concentrated to obtain a concentrated liquid and a potassium salt solid;

[0060] S6. Mix the concentrate with a pH adjuster (sodium hydroxide solution) and stir until the pH value reaches 12 to 13;

[0061] S7. The concentrated solution after adjusting the pH is mixed with the extractant (TBP) and stirred to control the phase ratio (O:A) to be 5:1, and the mixture is allowed to stand for stratification to obtain an upper organic phase and an aqueous phase;

[0062] S8. The second extracted liquid in S3 (the organic phase in S7) is mixed and stirred with the stripping agent (sulfuric acid solution), the phase ratio (O:A) is controlled to be 8:1, and the mixture is allowed to stand and separate into an upper organic phase and an aqueous phase;

[0063] S9. The first stripping liquid in S8 (the aqueous phase in S8) is evaporated and concentrated to obtain cesium sulfate solid.

[0064] Example 4

[0065] This embodiment provides a method for extracting high-purity cesium sulfate from high-salinity wastewater, which comprises:

[0066] S1. Freeze the high-salt wastewater at -3~0℃ to obtain sodium salt solid and frozen liquid;

[0067] S2. Mix the frozen liquid with a pH adjuster (sodium hydroxide solution) and stir until the pH value reaches 12 to 13;

[0068] S3. The pH-adjusted frozen liquid is mixed with the extractant (TBP) and stirred to control the phase ratio (O:A) to be 2:1, and the mixture is allowed to stand and separate into an upper organic phase and an aqueous phase;

[0069] S4. The first extracted liquid in S3 (the organic phase in S3) is mixed with the stripping agent (sulfuric acid solution) and stirred, and the phase ratio (O:A) is controlled to be 4:1, and the mixture is allowed to stand and separate to obtain an upper organic phase and an aqueous phase;

[0070] S5. The first stripping liquid (aqueous phase in S4) in S4 is evaporated and concentrated to obtain a concentrated liquid and a potassium salt solid;

[0071] S6. Mix the concentrate with a pH adjuster (sodium hydroxide solution) and stir until the pH value reaches 12 to 13;

[0072] S7. The concentrated solution after adjusting the pH is mixed with the extractant (TBP) and stirred to control the phase ratio (O:A) to be 2:1, and the mixture is allowed to stand for stratification to obtain an upper organic phase and an aqueous phase;

[0073] S8. The second extracted liquid in S3 (the organic phase in S7) is mixed and stirred with the stripping agent (sulfuric acid solution), the phase ratio (O:A) is controlled to be 4:1, and the mixture is allowed to stand and separate into an upper organic phase and an aqueous phase;

[0074] S9. The first stripping liquid in S8 (the aqueous phase in S8) is evaporated and concentrated to obtain cesium sulfate solid.

[0075] Example 5

[0076] This embodiment provides a method for extracting high-purity cesium sulfate from high-salinity wastewater, which comprises:

[0077] S1. Freeze the high-salt wastewater at 0-3°C to obtain sodium salt solid and frozen liquid;

[0078] S2. Mix the frozen liquid with a pH adjuster (sodium hydroxide solution) and stir until the pH value reaches 12 to 13;

[0079] S3. The pH-adjusted frozen liquid is mixed with the extractant (TBP) and stirred to control the phase ratio (O:A) to be 3:1, and the mixture is allowed to stand and separate into an upper organic phase and an aqueous phase;

[0080] S4. The first extracted liquid in S3 (the organic phase in S3) is mixed with the stripping agent (sulfuric acid solution) and stirred, and the phase ratio (O:A) is controlled to be 6:1, and the mixture is allowed to stand and separate to obtain an upper organic phase and an aqueous phase;

[0081] S5. The first stripping liquid (aqueous phase in S4) in S4 is evaporated and concentrated to obtain a concentrated liquid and a potassium salt solid;

[0082] S6. Mix the concentrate with a pH adjuster (sodium hydroxide solution) and stir until the pH value reaches 12 to 13;

[0083] S7. The concentrated solution after pH adjustment is mixed with the extractant (TBP) and stirred to control the phase ratio (O:A) to be 3:1, and the mixture is allowed to stand for stratification to obtain an upper organic phase and an aqueous phase;

[0084] S8. The second extracted liquid in S3 (the organic phase in S7) is mixed and stirred with the stripping agent (sulfuric acid solution), the phase ratio (O:A) is controlled to be 6:1, and the mixture is allowed to stand for stratification to obtain an upper organic phase and an aqueous phase;

[0085] S9. The first stripping liquid in S8 (the aqueous phase in S8) is evaporated and concentrated to obtain cesium sulfate solid.

[0086] Test example

[0087] The high-salt wastewater was treated by the methods of Examples 3 to 6, and the sodium ion and sulfate ion contents in the frozen liquid after step S1, as well as the purity of the final cesium sulfate solid were recorded respectively. The high-salt wastewater used was measured in advance and contained 1.24 g / l of cesium, 61.7 g / l of potassium, 94.3 g / l of sodium, 52.7 g / l of sulfate, and 147.8 g / l of chloride. The test results are shown in Table 1.

[0088] Table 1. Ion concentration measurement results

[0089] Sodium ion concentration (g / l) Sulfate ion concentration (g / l) Cesium sulfate purity (%) Example 1 53.2 21.6 94.7 Example 2 57.7 24.9 92.8 Example 3 62.8 28.7 92.2

[0090] As can be seen from Table 1, after freezing the high-salt wastewater using the methods of Examples 1 to 3 of the present invention, the sodium ion content was reduced by 33% to 44%, and the sulfate ion content was reduced by 45% to 60%, which significantly reduced the sodium ion and sulfate ion content in the high-salt wastewater and improved the efficiency of subsequent extraction. At the same time, the purity of the cesium sulfate solid obtained after treatment by this method can reach more than 92%, which has a better utilization value.

[0091] In summary, the embodiment of the present invention provides a method for extracting high-purity cesium sulfate from high-salt wastewater, which is to first freeze the high-salt wastewater so that the sodium ions therein are precipitated in the form of high-grade sodium sulfate, and the sodium ions and sulfate ion contents in the frozen liquid are reduced. Subsequently, the potassium ions are crystallized and precipitated by the first extraction and stripping, and the stripping liquid is evaporated for the first time. Finally, the evaporated liquid is subjected to secondary extraction, stripping, and evaporation to obtain a high-grade cesium sulfate product. It is not only simple and convenient to operate, but also has low requirements for equipment and has good practical value. A device for extracting high-purity cesium sulfate from high-salt wastewater, the device is used in conjunction with the above method, including a refrigeration tank, a first extraction tank, a first evaporation tank, a second extraction tank, and a second evaporation tank connected in series in sequence. It is not only simple in structure and easy to use, but also has high processing efficiency.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for extracting high-purity cesium sulfate from high-salinity wastewater, characterized in that: include: Freezing the high-salt wastewater to obtain a sodium salt solid and a frozen liquid; Sequentially extracting and stripping the frozen liquid to obtain a first stripped liquid; The first stripping solution is evaporated and concentrated to obtain a concentrated solution and a potassium salt solid; Extracting and stripping the concentrated liquid once to obtain a second stripping liquid; The second stripping liquid is evaporated and concentrated to obtain cesium sulfate solid; The high-salt wastewater is saline wastewater produced during the washing of high-chlorine-containing materials, which contains 0.5-1.5 g / l of cesium, 40-70 g / l of potassium, 90-100 g / l of sodium, 50-60 g / l of sulfate, and 130-160 g / l of chloride ions; The frozen liquid / the concentrated liquid is extracted and stripped by first mixing the frozen liquid / the concentrated liquid with a pH regulator to adjust the pH value to alkaline, then mixing with an extractant, and collecting the organic phase after standing and stratifying and mixing with a stripping agent; wherein the pH regulator is an aqueous solution of potassium hydroxide or sodium hydroxide, the extractant is TBP, and the stripping agent is an aqueous solution of sulfuric acid; During the mixing process with the extractant, the phase ratio (O:A) is controlled to be 2-5:1; during the mixing process with the stripping agent, the phase ratio (O:A) is controlled to be 4-8:

1.

2. The method for extracting high-purity cesium sulfate from high-salinity wastewater according to claim 1, characterized in that: The temperature for freezing the high-salinity wastewater is -5~3°C.

3. The method for extracting high-purity cesium sulfate from high-salt wastewater according to claim 2, characterized in that: After the frozen liquid / the concentrated liquid is mixed with the pH adjuster, the pH value is 12-13.

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