System for recovering hydroxide from oxalic acid waste liquid

Abstract

The utility model belongs to the technical field of chemical industry production, and provides a system for recovering hydroxide from oxalic acid waste liquid, which comprises a reaction module, a second reaction module, a third reaction module, a fourth reaction module, a fifth reaction module and a sixth reaction module, wherein the reaction module is used for mixing the oxalic acid waste liquid with an organic solution to obtain an organic phase containing transition metal ions and mixing the organic phase with alkali liquor to obtain a first mixture containing hydroxide precipitate; the separation module is used for separating the hydroxide precipitate from the mixture to obtain a solid; a washing module for obtaining a second mixture by washing the solids with a detergent; and the solid-liquid separation module is used for separating the detergent in the second mixture from the hydroxide precipitate to obtain the hydroxide precipitate. According to the utility model, the washing module is used for washing the hydroxide precipitate separated from the separation module, and the washing agent and the hydroxide precipitate are separated through the solid-liquid separation module after washing, so that impurities on the hydroxide precipitate are removed, and the quality of subsequent production procedures is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical production, and particularly relates to a system for recovering hydroxides from oxalic acid waste liquid. Background Technique

[0002] Oxalic acid is a naturally occurring organic compound belonging to the dicarboxylic acid class. It was first extracted from the mild rhubarb plant and has received wide attention due to its widespread presence and relatively easy availability.

[0003] Oxalic acid waste liquid refers to the waste liquid containing oxalic acid and its by-products generated in industrial or laboratory processes. Such waste liquid is usually generated during the production, use, or treatment of oxalic acid and may contain trace amounts of transition metal elements. When dealing with these transition metal elements, these transition metal elements are usually converted into hydroxide solids and then recovered as raw materials for subsequent production processes.

[0004] CN202211126427.7 discloses a method for recovering scandium oxide from a scandium-containing loaded organic phase, belonging to the technical field of hydrometallurgy of rare earth metals. By means of dispersion and alkali liquor back-extraction, the scandium-containing substance is separated from the difficult-to-treat loaded organic phase, effectively avoiding the losses and environmental pollution problems caused by incinerating the organic phase in the prior art; and by limiting the parameters in the process of recovering scandium oxide, the recovery rate of scandium oxide can be improved, and the waste of scandium elements in the organic phase is greatly reduced.

[0005] In the above technical solution, the scandium-containing loaded organic phase is dispersed, back-extracted, acid-leached, precipitated with oxalic acid, and calcined to obtain scandium oxide. However, since it is not washed, there will still be a small amount of impurities on the scandium hydroxide separated from the mixed solution. If the scandium hydroxide with a small amount of impurities is used as a raw material, it will affect the quality of the subsequent processes. Summary of the Utility Model

[0006] The purpose of the utility model is to solve the above problems, and provides a system for recovering hydroxides from oxalic acid waste liquid. The system uses a washing module to wash the hydroxide precipitate separated from the separation module, and after washing, separates the detergent from the hydroxide precipitate through a solid-liquid separation module. In this way, the impurities on the hydroxide precipitate are removed, and the quality of the subsequent production processes is improved.

[0007] To achieve the above purpose, the utility model provides the following technical solutions:

[0008] A system for recovering hydroxides from oxalic acid waste liquid, comprising:

[0009] A reaction module: used for mixing oxalic acid waste liquid with an organic solution to obtain an organic phase containing transition metal ions, and mixing the organic phase with an alkali liquor to obtain a first mixture containing hydroxide precipitate;

[0010] Separation module: used to separate the hydroxide precipitate from the mixture to obtain a solid;

[0011] Washing module: used to obtain a second mixture by washing the solid with a detergent;

[0012] Solid-liquid separation module: used to separate the detergent from the hydroxide precipitate in the second mixture to obtain the hydroxide precipitate;

[0013] The reaction module, separation module, washing module, and solid-liquid separation module are connected in sequence.

[0014] In the above-mentioned hydroxide recovery system from oxalic acid waste liquid, the reaction module includes a reaction tank and a back-extraction tank;

[0015] The reaction tank is provided with a first feed pipe connected to an externally provided oxalic acid waste liquid conveying device, a second feed pipe connected to an externally provided organic solution conveying device, and a first discharge pipe for outputting the organic phase to the back-extraction tank;

[0016] The back-extraction tank is provided with a third feed pipe connected to an externally provided lye conveying device; a second discharge pipe connected to the separation module is also provided at the bottom of the back-extraction tank, and a first transfer pump is provided on the second discharge pipe.

[0017] In the above-mentioned hydroxide recovery system from oxalic acid waste liquid, the separation module includes a disc centrifuge and a screw conveyor;

[0018] The light-phase outlet of the disc centrifuge is connected to an externally provided light-phase storage tank, and the heavy-phase outlet of the disc centrifuge is connected to an externally provided heavy-phase storage tank; the screw conveyor is arranged below the solid-phase outlet of the disc centrifuge, and the screw conveyor is used to convey the solid separated from the disc centrifuge to the washing module.

[0019] In the above-mentioned hydroxide recovery system from oxalic acid waste liquid, the washing module includes a washing tank, and the washing tank is provided with a water delivery pipe connected to an externally provided water delivery device;

[0020] The bottom of the washing tank is provided with a third discharge pipe connected to the solid-liquid separation module, and a second transfer pump is provided on the third discharge pipe.

[0021] In the above-mentioned hydroxide recovery system from oxalic acid waste liquid, the solid-liquid separation module includes a two-phase centrifuge connected to the third discharge pipe, a hopper, a silo, and a first liquid storage tank;

[0022] The hopper is arranged below the solid-phase discharge port of the two-phase centrifuge, and the silo is arranged below the hopper;

[0023] The first liquid storage tank is connected to the liquid outlet of the two-phase centrifuge.

[0024] In the above-mentioned hydroxide recovery system from oxalic acid waste liquid, an external coil is provided on the outer wall of the stripping tank, and steam can be introduced into the external coil to heat the stripping tank, or cooling water can be introduced to lower the temperature of the stripping tank.

[0025] In the above-mentioned hydroxide recovery system from oxalic acid waste liquid, a liquid level gauge and a temperature sensor are also provided on the stripping tank.

[0026] In the above-mentioned hydroxide recovery system from oxalic acid waste liquid, the metal recovery system of the oxalic acid waste liquid further includes a tee, a spray tower, and a condenser. The condenser is vertically arranged, and the air inlet of the condenser is communicated with the reaction tank;

[0027] The main pipe of the tee is connected to the spray tower, the first branch pipe of the tee is connected to the air outlet of the condenser, the second branch pipe of the tee is connected to the reaction tank, and a wind pressure sensor and a centrifugal fan are provided on the main pipe of the tee.

[0028] In the above-mentioned hydroxide recovery system from oxalic acid waste liquid, a first flow meter is provided on the first feed pipe, and a second flow meter is provided on the second feed pipe.

[0029] In the above-mentioned hydroxide recovery system from oxalic acid waste liquid, a fourth discharge pipe is further provided at the bottom of the reaction tank. A third transfer pump, an oil-water separator for filtering organic solutions, and a storage tank are successively arranged on the fourth discharge pipe. The third transfer pump is used to transfer the remaining liquid in the reaction tank to the storage tank.

[0030] Compared with the prior art, the beneficial effects of the present utility model are:

[0031] In the present utility model, the hydroxide precipitate separated from the separation module is washed by the washing module, and after washing, the detergent is separated from the hydroxide precipitate by the solid-liquid separation module. In this way, the impurities on the hydroxide precipitate are removed, and the quality of the subsequent production process is improved. Description of the Drawings

[0032] Figure 1 It is a schematic structural diagram of a hydroxide recovery system from oxalic acid waste liquid in Embodiment 1;

[0033] Figure 2 It is a schematic structural diagram of the reaction tank of a hydroxide recovery system from oxalic acid waste liquid in Embodiment 1;

[0034] Figure 3 It is a schematic structural diagram of the stripping tank of a hydroxide recovery system from oxalic acid waste liquid in Embodiment 1;

[0035] Among them, the reference numerals of each figure:

[0036] 1. Reaction module; 11. Reaction tank; 111. First feed pipe; 1111. First flowmeter; 112. Second feed pipe; 1121. Second flowmeter; 113. First discharge pipe; 114. Fourth discharge pipe; 1141. Third transfer pump; 1142. Oil-water separator; 1143. Storage tank; 12. Back-extraction tank; 121. Third feed pipe; 122. Second discharge pipe; 1221. First transfer pump; 123. External coil; 124. Liquid level gauge; 125. Temperature sensor; 2. Separation module; 21. Disc centrifuge; 22. Screw conveyor; 3. Washing module; 31. Washing tank; 311. Water supply pipe; 312. Third discharge pipe; 3121. Second transfer pump; 4. Solid-liquid separation module; 41. Two-phase centrifuge; 42. Hopper; 43. Silo; 44. Liquid storage tank; 5. Three-way pipe; 51. Main pipe; 511. Centrifugal fan; 512. Wind pressure sensor; 52. First branch pipe; 53. Second branch pipe; 6. Spray tower; 7. Condenser. Detailed implementation manners

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0038] Embodiment 1

[0039] Reference Figures 1 to 3 , a system for recovering hydroxides from oxalic acid waste liquid, comprising:

[0040] Reaction module 1: used for mixing oxalic acid waste liquid with an organic solution to obtain an organic phase containing transition metal ions, and mixing the organic phase with an alkali solution to obtain a first mixture containing hydroxide precipitate;

[0041] Separation module 2: used for separating the hydroxide precipitate from the mixture to obtain a solid;

[0042] Washing module 3: used for washing the solid with a detergent to obtain a second mixture;

[0043] Solid-liquid separation module 4: used for separating the detergent in the second mixture from the hydroxide precipitate to obtain a hydroxide precipitate;

[0044] The reaction module 1, the separation module 2, the washing module 3, and the solid-liquid separation module 4 are connected in sequence.

[0045] Under this design, first, the oxalic acid waste liquid is mixed with the organic solution in the reaction module 1 to obtain an organic phase containing transition metal ions. Then, an alkali solution is added to mix with the obtained organic phase to obtain a first mixture containing hydroxide precipitate. Next, the separation module 2 is used to separate the hydroxide precipitate from the first mixture to obtain a solid. Then, the solid is washed with a detergent to obtain a second mixture. Finally, the hydroxide precipitate is separated from the second mixture in the solid-liquid module to obtain the hydroxide precipitate. In this way, the impurities on the hydroxide precipitate are removed, and the quality of the subsequent production process is improved.

[0046] In this embodiment, the reaction module 1 includes a reaction tank 11 and a stripping tank 12.

[0047] The reaction tank 11 is provided with a first feed pipe 111 connected to an externally provided oxalic acid waste liquid delivery device, a second feed pipe 112 connected to an externally provided organic solution delivery device, and a first discharge pipe 113 for outputting the organic phase to the stripping tank 12.

[0048] The stripping tank 12 is provided with a third feed pipe 121 connected to an externally provided alkali solution delivery device. The bottom of the stripping tank 12 is further provided with a second discharge pipe 122 connected to the separation module 2, and a first transfer pump 1221 is provided on the second discharge pipe 122.

[0049] Specifically, first, the organic solution is passed into the reaction tank 11 through the second feed pipe 112. Then, the oxalic acid waste liquid is transported into the reaction tank 11 through the first feed pipe 111, so that the transition metal ions in the oxalic acid waste liquid are transferred into the organic solution to obtain an organic phase containing transition metal ions. Then, the organic phase is output to the stripping tank 12 through the first discharge pipe 113. Next, the alkali solution is transported into the stripping tank 12 through the third feed pipe 121 to generate a first mixture containing hydroxide precipitate. Finally, the first mixture is output by the first transfer pump 1221. In this way, the first mixture will enter the separation module 2 after passing through the second discharge pipe 122.

[0050] In practical applications, the separation module 2 includes a disc centrifuge 21 and a screw conveyor 22.

[0051] The light phase outlet of the disc centrifuge 21 is connected to an externally provided light phase storage tank, and the heavy phase outlet of the disc centrifuge 21 is connected to an externally provided heavy phase storage tank. The screw conveyor 22 is arranged below the solid phase outlet of the disc centrifuge 21, and the screw conveyor 22 is used to transport the solid separated from the disc centrifuge 21 to the washing module 3.

[0052] Specifically, when the organic phase is output, due to precision issues, there is some light phase in the organic phase. Under the action of the disc centrifuge 21, the light phase will be stored in the peripheral light phase storage tank, the heavy phase will be stored in the peripheral heavy phase storage tank, and the separated solid will exit from the solid phase outlet of the disc centrifuge 21 and fall into the screw conveyor 22 below. The screw conveyor 22 will convey the solid to the washing module 3.

[0053] Preferably, the washing module 3 includes a washing tank 31, and a water inlet pipe 311 connected to a peripheral water delivery device is provided on the washing tank 31;

[0054] A third discharge pipe 312 connected to the solid-liquid separation module 4 is provided at the bottom of the washing tank 31, and a second delivery pump 3121 is provided on the third discharge pipe 312.

[0055] Further, the screw conveyor 22 will convey the solid into the washing tank 31, and then water will be input into the washing tank 31 through a peripheral water delivery device to wash the impurities on the solid. After the washing is completed, under the action of the second delivery pump 3121, the water and solid in the washing tank 31 will be conveyed to the solid-liquid separation module 4 by using the third discharge pipe 312.

[0056] More preferably, the solid-liquid separation module 4 includes a two-phase centrifuge 41 connected to the third discharge pipe 312, a hopper 42, a bin 43, and a first liquid storage tank 44;

[0057] The hopper 42 is arranged below the solid phase discharge port of the two-phase centrifuge 41, and the bin 43 is arranged below the hopper 42;

[0058] The first liquid storage tank 44 is connected to the liquid outlet of the two-phase centrifuge 41.

[0059] Specifically, after the water and solid enter the two-phase centrifuge 41, the two-phase centrifuge 41 will separate the water and the solid. The separated water will be stored in the first liquid storage tank 44, and the hydroxide precipitate will exit from the solid phase discharge port and enter the bin 43 after passing through the hopper 42.

[0060] Preferably, an external coil 123 is provided on the outer wall of the stripping tank 12. Steam can be introduced into the external coil 123 to heat the stripping tank 12, or cooling water can be introduced to lower the temperature of the stripping tank 12.

[0061] Specifically, in order to accelerate the reaction rate in the stripping tank 12, steam is introduced into the external coil 123 to heat the temperature of the stripping tank 12 and thus increase the reaction rate in the stripping tank 12. When the temperature in the stripping tank 12 is too high, cooling water is introduced into the external coil 123 to lower the temperature of the stripping tank 12.

[0062] Preferably, a liquid level gauge 124 and a temperature sensor 125 are also provided on the stripping tank 12. The liquid level gauge 124 is used to detect the liquid level in the stripping tank 12, and the temperature of the stripping tank 12 is detected by the temperature sensor 125.

[0063] In this embodiment, the metal recovery system for oxalic acid waste liquid further includes a three-way pipe 5, a spray tower 6, and a condenser 7. The condenser 7 is vertically arranged, and the air inlet of the condenser 7 is communicated with the reaction tank 11;

[0064] The main pipe 51 of the three-way pipe 5 is connected to the spray tower 6, the first branch pipe 52 of the three-way pipe 5 is connected to the air outlet of the condenser 7, the second branch pipe 53 of the three-way pipe 5 is connected to the reaction tank 11, and a wind pressure sensor 512 and a centrifugal fan 511 are provided on the main pipe 51 of the three-way pipe 5.

[0065] Furthermore, both the reaction tank 11 and the stripping tank 12 will have waste gas. Moreover, during the process of introducing steam into the external coil 123 to heat the stripping tank 12, the organic phase is likely to volatilize, which will increase the difficulty of waste gas treatment. Therefore, the centrifugal fan 511 is used to extract the waste gas from the reaction tank 11 and the stripping tank 12. The condenser 7 first condenses the volatilized organic phase so that the organic phase can flow back to the stripping tank 12. The waste gas of the reaction tank 11 enters the main pipe 51 through the second branch pipe 53, and the waste gas in the stripping tank 12 enters the main pipe 51 through the first branch pipe 52. These waste gases are finally discharged after being treated in the spray tower 6. At the same time, the wind pressure sensor 512 is used to detect the change in pressure during gas flow.

[0066] Preferably, a first flowmeter 1111 is provided on the first feed pipe 111, and a second flowmeter 1121 is provided on the second feed pipe 112; the first flowmeter 1111 is used to detect the amount of the input oxalic acid waste liquid, and the amount of the input organic solution is detected by the second flowmeter 1121.

[0067] More preferably, a fourth discharge pipe 114 is further provided at the bottom of the reaction tank 11. A third transfer pump 1141, an oil-water separator 1142, and a storage tank 1143 are successively provided on the fourth discharge pipe 114. The third transfer pump 1141 is used to transfer the remaining liquid in the reaction tank 11 to the storage tank 1143.

[0068] Specifically, the remaining liquid in the reaction tank 11 may contain some organic solution. Therefore, when the third transfer pump 1141 transfers the remaining liquid in the reaction tank 11 to the storage tank 1143, the oil-water separator 1142 is used to filter the organic solution in the liquid first and then store it.

[0069] Implicitly, in order to control the on-off of material output and input, valves are provided on the first feed pipe 111, the second feed pipe 112, the third feed pipe 121, the first discharge pipe 113, and the water supply pipe 311.

[0070] The above are only the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements or modifications can be made, and these improvements or modifications should also be regarded as the protection scope of the present utility model.

Claims

1. A hydroxide recovery system from oxalic acid waste liquid, characterized in that, Comprising: Reaction module: used to mix oxalic acid waste liquid with an organic solution to obtain an organic phase containing transition metal ions, and mix the organic phase with an alkali solution to obtain a first mixture containing hydroxide precipitate; Separation module: used to separate the hydroxide precipitate from the mixture to obtain a solid; Washing module: used to obtain a second mixture by washing the solid with a detergent; Solid-liquid separation module: used to separate the detergent in the second mixture from the hydroxide precipitate to obtain the hydroxide precipitate; The reaction module, separation module, washing module, and solid-liquid separation module are connected in sequence.

2. The hydroxide recovery system from oxalic acid waste liquid according to claim 1, wherein The reaction module includes a reaction tank and a stripping tank; The reaction tank is provided with a first feed pipe connected to an externally provided oxalic acid waste liquid conveying device, a second feed pipe connected to an externally provided organic solution conveying device, and a first discharge pipe for outputting the organic phase to the stripping tank; The stripping tank is provided with a third feed pipe connected to an externally provided alkali solution conveying device; the bottom of the stripping tank is further provided with a second discharge pipe connected to the separation module, and a first transfer pump is provided on the second discharge pipe.

3. The hydroxide recovery system from oxalic acid waste liquid according to claim 2, characterized in that, The separation module includes a disc centrifuge and a screw conveyor; The light phase outlet of the disc centrifuge is connected to an externally provided light phase storage tank, and the heavy phase outlet of the disc centrifuge is connected to an externally provided heavy phase storage tank; the screw conveyor is arranged below the solid phase outlet of the disc centrifuge, and the screw conveyor is used to convey the solid separated from the disc centrifuge to the washing module.

4. The hydroxide recovery system for oxalic acid waste liquid according to claim 3, wherein The washing module includes a washing tank, and the washing tank is provided with a water delivery pipe connected to an externally provided water delivery device; The bottom of the washing tank is provided with a third discharge pipe connected to the solid-liquid separation module, and a second transfer pump is provided on the third discharge pipe.

5. The hydroxide recovery system from oxalic acid waste liquid according to claim 4, wherein, The solid-liquid separation module includes a two-phase centrifuge connected to the third discharge pipe, a hopper, a silo, and a first liquid storage tank; The hopper is arranged below the solid phase discharge port of the two-phase centrifuge, and the silo is arranged below the hopper; The first liquid storage tank is connected to the liquid outlet of the two-phase centrifuge.

6. The hydroxide recovery system for oxalic acid waste liquid according to claim 2, characterized in that, An external coil is provided on the outer wall of the stripping tank, and steam can be introduced into the external coil to heat the stripping tank, or cooling water can be introduced to lower the temperature of the stripping tank.

7. An oxalic acid waste liquid recycling hydroxide system according to claim 6, characterized in that, A liquid level gauge and a temperature sensor are further provided on the stripping tank.

8. A hydroxide recovery system for oxalic acid waste liquid according to claim 6, characterized in that, The metal recovery system for oxalic acid waste liquid further includes a three-way pipe, a spray tower, and a condenser. The condenser is arranged vertically, and the air inlet of the condenser is communicated with the reaction tank; The main pipe of the three-way pipe is connected to the spray tower, the first branch pipe of the three-way pipe is connected to the air outlet of the condenser, the second branch pipe of the three-way pipe is connected to the reaction tank, and a wind pressure sensor and a centrifugal fan are provided on the main pipe of the three-way pipe.

9. The hydroxide recovery system from oxalic acid waste liquid according to claim 8, characterized in that, A first flow meter is provided on the first feed pipe, and a second flow meter is provided on the second feed pipe.

10. A hydroxide recovery system for oxalic acid waste liquid according to claim 2, wherein, A fourth discharge pipe is further provided at the bottom of the reaction tank, and a third transfer pump, an oil-water separator for filtering the organic solution, and a storage tank are sequentially provided on the fourth discharge pipe. The third transfer pump is used to convey the remaining liquid in the reaction tank to the storage tank.

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