Production device and process for recovering electronic-grade phosphoric acid from waste etching liquid

Abstract

The invention provides a production device and process for recovering electronic-grade phosphoric acid from waste etching liquid. The device comprises a raw material storage tank, a multi-stage filtration system, a phosphoric acid evaporation kettle, a purification system, a mixed acid storage tank and a neutralization reaction and crystallization system. The waste etching liquid enters an evaporation kettle after being subjected to multi-stage filtration to remove suspended solid particles, and phosphoric acid is separated from volatile nitric acid and acetic acid; and condensing the volatile acid into mixed acid for storage, and removing metal ions from the semi-finished phosphoric acid through a purification system to obtain the electronic-grade phosphoric acid. The mixed acid reacts with alkali to generate a mixed solution of sodium acetate and nitric acid, sodium acetate crystals are separated out through evaporation and concentration, a solid product is obtained after separation, nitric acid is obtained by condensing gas, and suspended particles and metal impurities are subjected to incineration treatment. Through the steps of filtering, negative-pressure evaporation, neutralization and crystallization and the like, the process realizes efficient recovery of electronic-grade phosphoric acid and byproducts of sodium acetate and nitric acid, and has the characteristics of high resource recovery rate and low pollution emission.

Description

Technical Field

[0001] The present invention relates to the field of phosphoric acid recovery, and particularly to a production device and a production process for recovering electronic-grade phosphoric acid from waste phosphoric acid etching solution. Background Art

[0002] In the wet etching process of liquid crystal panels (Thin film transistor liquid crystal display, abbreviated as TFT-LCD), phosphoric acid-based etching solutions are mainly used for etching Al or Mo alloys. A large amount of Al / Mo etching waste acid is generated in the gate and drain etching processes. The Al / Mo etching waste acid is composed of phosphoric acid, acetic acid, nitric acid, and water, and also contains a large amount of metal ions such as Al and Mo. It is a highly hazardous waste acid with strong acidity. Recycling the Al / Mo etching waste acid for the production of electronic-grade phosphoric acid and by-products of sodium acetate and nitric acid products can realize the recovery and secondary utilization of waste etching solution, which can not only save resources but also reduce the emission of pollutants. Summary of the Invention

[0003] Based on this, it is necessary to provide a production device and a production process for recovering electronic-grade phosphoric acid from waste etching solution.

[0004] A production device for recovering electronic-grade phosphoric acid from waste etching solution includes a raw material storage tank, a raw material transfer pump, a primary filter, a secondary filter, a phosphoric acid evaporation kettle, a phosphoric acid semi-finished product transfer pump, a phosphoric acid purification system, a phosphoric acid product storage tank, an evaporation condenser, a mixed acid storage tank, a mixed acid transfer pump, a sodium acetate reaction kettle, a reaction product transfer pump, a sodium acetate evaporator, a sodium acetate concentrated solution transfer pump, a sodium acetate crystallization kettle, a crystal transfer pump, a sodium acetate product separator, a nitric acid condenser, and a nitric acid product storage tank, which are connected through pipelines. The outlet of the raw material storage tank is connected to the inlet of the raw material transfer pump through a pipeline, and the raw material transfer pump is connected to the filtration system.

[0005] In one embodiment, for the production device for recovering electronic-grade phosphoric acid from the waste etching solution, the filtration system includes a primary filter and a secondary filter; the primary filter and the secondary filter can be used in series or in parallel. The types of the primary filter and the secondary filter are one of a bag filter, a basket filter, a Y-type filter, a T-type filter, a security filter, a precision filter, etc., and the preferred type is a bag filter.

[0006] In one embodiment, the production device for recovering electronic-grade phosphoric acid from the waste etching solution further includes a phosphoric acid evaporation kettle, a phosphoric acid semi-finished product transfer pump, a phosphoric acid purification system, and a phosphoric acid product storage tank;

[0007] The filtration system is communicated with the liquid phase inlet of the phosphoric acid evaporation kettle; the bottom liquid phase outlet of the phosphoric acid evaporation kettle is communicated with the inlet of the phosphoric acid semi-finished product transfer pump, the outlet of the phosphoric acid semi-finished product transfer pump is communicated with the phosphoric acid purification system, and the phosphoric acid purification system is connected with the phosphoric acid product storage tank;

[0008] The phosphoric acid purification system is one of an ion exchange resin complete set of devices, an activated carbon adsorption complete set of devices, a membrane filtration system complete set of devices, and a crystallization system complete set of devices, preferably an ion exchange resin complete set of devices;

[0009] The outer jacket of the phosphoric acid evaporation kettle is also communicated with a steam inlet and a steam condensate outlet.

[0010] In one embodiment, the production device for recovering electronic-grade phosphoric acid from waste etching solution further includes an evaporation condenser and a mixed acid storage tank; the gas phase outlet at the top of the phosphoric acid evaporation kettle is communicated with the gas phase inlet of the evaporation condenser through a pipeline; the liquid phase outlet of the evaporation condenser is communicated with the mixed acid storage tank through a pipeline.

[0011] In one embodiment, the production device for recovering electronic-grade phosphoric acid from waste etching solution further includes a mixed acid transfer pump, a sodium acetate reaction kettle, a reaction product transfer pump, a sodium acetate evaporator, a sodium acetate concentrated solution transfer pump, and a sodium acetate crystallization kettle; wherein,

[0012] The outlet of the mixed acid storage tank is communicated with the inlet of the mixed acid transfer pump; the outlet of the mixed acid transfer pump is sequentially communicated with the material inlet of the sodium acetate reaction kettle, the material outlet of the sodium acetate reaction kettle, the inlet of the reaction product transfer pump, the outlet of the reaction product transfer pump, the material inlet of the sodium acetate evaporator, the material outlet of the sodium acetate evaporator, the inlet of the sodium acetate concentrated solution transfer pump, the outlet of the sodium acetate concentrated solution transfer pump, and the material inlet of the sodium acetate crystallization kettle through pipelines;

[0013] The top of the sodium acetate reaction kettle is also communicated with a sodium hydroxide feeding port; the shell side of the sodium acetate reaction kettle is also communicated with a cooling water inlet and a cooling water outlet

[0014] The outer jacket of the sodium acetate evaporator is also communicated with a steam inlet and a steam condensate outlet;

[0015] The outer jacket of the sodium acetate crystallization kettle is also communicated with a cooling water inlet and a cooling water outlet.

[0016] In one embodiment, the production device for recovering electronic-grade phosphoric acid from waste etching solution further includes a crystal transfer pump and a sodium acetate product separator; the inlet of the crystal transfer pump is communicated with the material outlet of the sodium acetate crystallization kettle, the outlet of the crystal transfer pump is communicated with the sodium acetate product separator, the liquid phase outlet of the sodium acetate product separator is communicated with the mother liquor inlet of the sodium acetate evaporator, and the sodium acetate product separator is also communicated with a sodium acetate product discharge port;

[0017] The sodium acetate product separator is one of a complete set of filter press devices and a complete set of centrifuge devices, and preferably a complete set of centrifuge devices.

[0018] In one embodiment, the production device for recovering electronic-grade phosphoric acid from waste etching solution further includes a nitric acid condenser and a nitric acid product storage tank; the gas phase outlet at the top of the sodium acetate evaporator is communicated with the gas phase inlet of the nitric acid condenser through a pipeline; the liquid phase outlet of the nitric acid condenser is communicated with the nitric acid product storage tank through a pipeline.

[0019] An electronic-grade phosphoric acid recovery production process uses the production device for recovering electronic-grade phosphoric acid from waste etching solution described in any one of the above.

[0020] In one embodiment, in the production process for recovering electronic-grade phosphoric acid from waste etching solution, the phosphoric acid evaporation kettle operates under negative pressure. The operating pressure of the phosphoric acid evaporation kettle is 10 - 100 kPa (absolute pressure), and the evaporation temperature is 80 - 150 °C; the sodium acetate reaction kettle and the sodium acetate crystallization kettle operate under normal pressure; the sodium acetate evaporator operates under negative pressure;. The operating pressure of the sodium acetate evaporator is 10 - 100 kPa (absolute pressure), and the evaporation temperature is 50 - 120 °C.

[0021] In one embodiment, the production process specifically includes the following steps:

[0022] The waste phosphoric acid etching solution from the raw material storage tank enters the filtration system through the raw material transfer pump and the transfer pipeline. The filtration system is equipped with a primary filter and a secondary filter, which can be used in series or in parallel. The types of the primary filter and the secondary filter are selected from bag filters, basket filters, Y-type filters, T-type filters, security filters, precision filters, etc., and the preferred type is the bag filter. After the waste phosphoric acid etching solution filters out suspended solid particles in the filtration system, it enters the phosphoric acid evaporation kettle. The phosphoric acid evaporation kettle is heated by steam through the outer jacket of the phosphoric acid evaporation kettle. The steam volatilized from the phosphoric acid evaporation kettle enters the evaporation condenser. After the steam is cooled by cooling water, the condensate enters the mixed acid storage tank. The liquid phase at the bottom of the phosphoric acid evaporation kettle enters the phosphoric acid purification system through the phosphoric acid semi-finished product transfer pump. The phosphoric acid purification system is selected from a complete set of ion exchange resin devices, a complete set of activated carbon adsorption devices, a complete set of membrane filtration systems, a complete set of crystallization systems, etc., and the preferred is the complete set of ion exchange resin devices. The semi-finished phosphoric acid removes impurities such as metal ions in the phosphoric acid purification system, and the obtained product is the finished product of electronic-grade phosphoric acid, and the product enters the phosphoric acid product storage tank.

[0023] The discharge of the mixed acid storage tank enters the sodium acetate reaction kettle through the mixed acid transfer pump. Sodium hydroxide is added to the sodium acetate reaction kettle to carry out a neutralization reaction. The reaction process is cooled by cooling water, and the reaction product is a mixed solution of sodium acetate and nitric acid. The mixed solution enters the sodium acetate evaporator through the reaction product transfer pump. The mixed solution is heated by steam to evaporate the nitric acid therein and concentrate the sodium acetate solution. The concentrated sodium acetate solution enters the sodium acetate crystallization kettle through the sodium acetate concentrated solution transfer pump. The sodium acetate solution is cooled by cooling water to precipitate sodium acetate crystal particles. The solid-liquid mixture containing sodium acetate crystal particles enters the sodium acetate product separator through the crystal transfer pump to separate out the solid sodium acetate product, and the remaining mother liquor returns to the sodium acetate evaporator for further concentration. The sodium acetate product separator is selected from a complete set of filter presses or a complete set of centrifuges, and the preferred is the complete set of centrifuges. The gas volatilized from the top of the sodium acetate evaporator is condensed by the nitric acid condenser, and the condensate enters the nitric acid product storage tank as the nitric acid product.

[0024] The device and its production process for recovering electronic-grade phosphoric acid from the above waste etching solution are configured with a raw material storage tank, a raw material transfer pump, a primary filter, a secondary filter, a phosphoric acid evaporation kettle, a semi-finished phosphoric acid transfer pump, a phosphoric acid purification system, a phosphoric acid product storage tank, an evaporation condenser, a mixed acid storage tank, a mixed acid transfer pump, a sodium acetate reaction kettle, a reaction product transfer pump, a sodium acetate evaporator, a sodium acetate concentrated solution transfer pump, a sodium acetate crystallization kettle, a crystal transfer pump, a sodium acetate product separator, a nitric acid condenser, and a nitric acid product storage tank. The raw material waste phosphoric acid etching solution separates suspended solid particles in the primary filter and the secondary filter, and then separates phosphoric acid from nitric acid and acetic acid in the phosphoric acid evaporation kettle. Nitric acid and acetic acid volatilize and are condensed into a mixed acid of nitric acid and acetic acid by the evaporation condenser, and the mixed acid enters the mixed acid storage tank. The semi-finished phosphoric acid from which the miscellaneous acids are separated removes impurities such as metal ions in the phosphoric acid purification system, and the product after impurity removal is the finished product of electronic-grade phosphoric acid, and the product enters the phosphoric acid product storage tank. The mixed acid reacts with sodium hydroxide to form a mixed solution of sodium acetate and nitric acid, and the mixed solution is evaporated and concentrated by steam. After the concentrated solution is cooled, sodium acetate crystal particles are precipitated, and then solid sodium acetate products are obtained through the product separator. The gas volatilized during the evaporation process of the mixed solution is condensed to obtain nitric acid products. The separated suspended solid particles, metal ions and other impurities are further treated by incineration. The device and production process recover phosphoric acid in the waste etching solution by adopting systems such as negative pressure evaporation, neutralization reaction, cooling crystallization, solid-liquid separation, filtration and purification, produce electronic-grade phosphoric acid products and by-products of sodium acetate and nitric acid products, which not only realizes the recycling of effective resources in the waste phosphoric acid etching solution, but also reduces the emission of pollutants. Brief Description of the Drawings

[0025] Figure 1 It is a schematic structural diagram of a production device for recovering electronic-grade phosphoric acid from waste phosphoric acid etching solution in an embodiment, and the arrows in the figure indicate the flow direction of liquid and / or steam.

[0026] The description of the reference numerals in the drawings is as follows:

[0027] 1: Raw material storage tank; 2: Raw material transfer pump; 3: Primary filter; 4: Secondary filter; 5: Phosphoric acid evaporation kettle; 6: Semi-finished phosphoric acid transfer pump; 7: Phosphoric acid purification system; 8: Phosphoric acid product storage tank; 9: Evaporation condenser; 10: Mixed acid storage tank; 11: Mixed acid transfer pump; 12: Sodium acetate reaction kettle; 13: Reaction product transfer pump; 14: Sodium acetate evaporator; 15: Sodium acetate concentrated solution transfer pump; 16: Sodium acetate crystallization kettle; 17: Crystal transfer pump; 18: Sodium acetate product separator; 19: Nitric acid condenser; 20: Nitric acid product storage tank; 21, 22: Solid particles; 23, 28: Steam; 24, 29: Steam condensate; 25: Sodium hydroxide material; 26, 30: Cooling water inlet; 27, 31: Cooling water outlet; 32: Sodium acetate product; 33: Mother liquor. Detailed Embodiments

[0028] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0030] The waste etching solution is derived from the gate and drain etching processes in the liquid crystal panel manufacturing process. The main components of the waste etching solution are phosphoric acid, acetic acid, nitric acid, and water. In addition, it also contains a large amount of metal ions such as aluminum (Al) and molybdenum (Mo).

[0031] As Figure 1 shown, a production device for recovering electronic-grade phosphoric acid from waste phosphoric acid etching solution in an embodiment includes a raw material storage tank 1, a raw material transfer pump 2, a primary filter 3, a secondary filter 4, a phosphoric acid evaporation kettle 5, a phosphoric acid semi-finished product transfer pump 6, a phosphoric acid purification system 7, a phosphoric acid product storage tank 8, an evaporation condenser 9, a mixed acid storage tank 10, a mixed acid transfer pump 11, a sodium acetate reaction kettle 12, a reaction product transfer pump 13, a sodium acetate evaporator 14, a sodium acetate concentrated solution transfer pump 15, a sodium acetate crystallization kettle 16, a crystal transfer pump 17, a sodium acetate product separator 18, a nitric acid condenser 19, and a nitric acid product storage tank 20. The corresponding devices of the production device for recovering electronic-grade phosphoric acid from waste phosphoric acid etching solution in this embodiment are connected and communicated through pipeline connection mechanisms and the like.

[0032] Specifically, in this embodiment, the outlet of the raw material storage tank 1 is connected to the inlet of the raw material transfer pump 2 through a pipeline, and the raw material transfer pump 2 is connected to the filtration system.

[0033] During the etching process of liquid crystal panel production, the transportation and storage of waste etching solution, and the material transportation, etc., solid particle impurities may be mixed into the waste etching solution. In the subsequent recycling process of the waste etching solution, the presence of solid particle impurities will cause blockage of equipment and pipelines, and in severe cases, it will cause the production to stop. Before the resource recovery of the waste etching solution, by setting up a filtration system, the solid particle impurities mixed therein are removed, so as to ensure the continuous and stable operation of the subsequent production.

[0034] Specifically, the filtration system includes a primary filter 3 and a secondary filter 4. The primary filter 3 and the secondary filter 4 can be used in series or in parallel. The primary filter 3 and the secondary filter 4 are one of the types such as bag filters, basket filters, Y-type filters, T-type filters, security filters, precision filters, etc., and the preferred type is a bag filter.

[0035] Specifically, it further includes a phosphoric acid evaporation kettle 5, a phosphoric acid semi-finished product transfer pump 6, a phosphoric acid purification system 7, and a phosphoric acid product storage tank 8. The filtration system is connected to the liquid phase inlet of the phosphoric acid evaporation kettle 5. The bottom liquid phase outlet of the phosphoric acid evaporation kettle 5 is connected to the inlet of the phosphoric acid semi-finished product transfer pump 6, the outlet of the phosphoric acid semi-finished product transfer pump 6 is connected to the phosphoric acid purification system 7, and the phosphoric acid purification system 7 is connected to the phosphoric acid product storage tank 8.

[0036] Under normal pressure, the boiling points of phosphoric acid, acetic acid, and nitric acid are 158 °C (85% by mass phosphoric acid), 118 °C, and 83 °C respectively. According to the different boiling points of the three acids, the operating temperature of the evaporation process is controlled, and acetic acid and nitric acid in the waste acid are evaporated by a heat source, while phosphoric acid remains in the liquid phase. After the phosphoric acid is concentrated to more than 85% by mass, it is discharged from the bottom of the phosphoric acid evaporation kettle 5 as a semi-finished product. A large amount of metal ions such as aluminum and molybdenum are still contained in the phosphoric acid semi-finished product, and the metal ions are removed through the phosphoric acid purification system 7 to obtain an electronic-grade phosphoric acid product.

[0037] The phosphoric acid purification system 7 is one of an ion exchange resin complete set of devices, an activated carbon adsorption complete set of devices, a membrane filtration system complete set of devices, a crystallization system complete set of devices, and the preferred one is an ion exchange resin complete set of devices;

[0038] The ion exchange resin method is to exchange the cations (H + ) on the resin with the metal cations in the phosphoric acid semi-finished product, so as to adsorb and remove metal cations such as aluminum and molybdenum in the semi-finished product.

[0039] The outer jacket of the phosphoric acid evaporation kettle 5 is also connected to a steam inlet 23 and a steam condensate outlet 24. The steam inlet 23 is connected to an external steam pipeline to provide the heat source required for the evaporation process of the phosphoric acid evaporation kettle 5, and the condensate formed after the steam condenses is discharged from the steam condensate outlet 24.

[0040] Specifically, it further includes an evaporation condenser 9 and a mixed acid storage tank 10. The gas phase outlet at the top of the phosphoric acid evaporation kettle 5 is connected to the gas phase inlet of the evaporation condenser 9 through a pipeline; the liquid phase outlet of the evaporation condenser 9 is connected to the mixed acid storage tank 10 through a pipeline.

[0041] The acetic acid and nitric acid vapors volatilized from the phosphoric acid evaporation kettle 5 are condensed in the evaporation condenser 9 to form an acetic acid and nitric acid mixed solution, which is stored in the mixed acid storage tank 10.

[0042] Specifically, it further includes a mixed acid transfer pump 11, a sodium acetate reaction kettle 12, a reaction product transfer pump 13, a sodium acetate evaporator 14, a sodium acetate concentrated liquid transfer pump 15, and a sodium acetate crystallization kettle 16; the outlet of the mixed acid storage tank 10 is communicated with the inlet of the mixed acid transfer pump 11; the outlet of the mixed acid transfer pump 11 is sequentially communicated with the material inlet of the sodium acetate reaction kettle 12, the material outlet of the sodium acetate reaction kettle 12, the inlet of the reaction product transfer pump 13, the outlet of the reaction product transfer pump 13, the material inlet of the sodium acetate evaporator 14, the material outlet of the sodium acetate evaporator 14, the inlet of the sodium acetate concentrated liquid transfer pump 15, the outlet of the sodium acetate concentrated liquid transfer pump 15, and the material inlet of the sodium acetate crystallization kettle 16 through pipelines;

[0043] The top of the sodium acetate reaction kettle 12 is also communicated with a sodium hydroxide feeding port; the outer jacket of the sodium acetate reaction kettle 12 is also communicated with a cooling water inlet 26 and a cooling water outlet 27;

[0044] The sodium hydroxide material 25 is added into the sodium acetate reaction kettle 12 through the sodium hydroxide feeding port and reacts with acetic acid in the mixed acid to produce sodium acetate.

[0045] The outer jacket of the sodium acetate evaporator 14 is also communicated with a steam inlet 28 and a steam condensate outlet 29; the steam inlet 28 is connected to an external steam pipeline to provide the heat source required for the evaporation process of the sodium acetate evaporator 14, and the condensate formed after the steam is condensed is discharged from the steam condensate outlet 29.

[0046] The outer jacket of the sodium acetate crystallization kettle 16 is also communicated with a cooling water inlet 30 and a cooling water outlet 31.

[0047] The sodium acetate concentrated liquid discharged from the bottom of the sodium acetate evaporator 14 enters the sodium acetate crystallization kettle 16, and the cooling water is used to cool down the sodium acetate concentrated liquid. Based on the principle that the solubility of sodium acetate decreases with the decrease of temperature, sodium acetate crystals are precipitated at low temperature.

[0048] Specifically, it further includes a crystal transfer pump 17 and a sodium acetate product separator 18; the inlet of the crystal transfer pump 17 is communicated with the material outlet of the sodium acetate crystallization kettle 16, the outlet of the crystal transfer pump 17 is communicated with the sodium acetate product separator 18, the liquid phase outlet of the sodium acetate product separator 18 is communicated with the mother liquor inlet of the sodium acetate evaporator 14, and the sodium acetate product separator 18 is also communicated with a sodium acetate product discharge port 32;

[0049] The sodium acetate product separator 18 is one of a filter press complete set of devices and a centrifuge complete set of devices. Preferably, it is a centrifuge complete set of devices, and its solid-liquid separation efficiency is higher. The solid-liquid mixture containing sodium acetate crystal particles enters the centrifuge device, and through the centrifugal force of the centrifuge, the sodium acetate crystals are separated from the mother liquor 33. The mother liquor 33 is a saturated sodium acetate solution and returns to the sodium acetate evaporator 14 for further concentration.

[0050] Specifically, it further includes a nitric acid condenser 19 and a nitric acid product storage tank 20; the gas-phase outlet at the top of the sodium acetate evaporator 14 is communicated with the gas-phase inlet of the nitric acid condenser 19 through a pipeline; the liquid-phase outlet of the nitric acid condenser 19 is communicated with the nitric acid product storage tank 20 through a pipeline.

[0051] This embodiment also provides a production process for recovering electronic-grade phosphoric acid from waste etching solution. During the operation of this production process, it specifically includes the following steps:

[0052] The waste phosphoric acid etching solution from the raw material storage tank 1 enters the filtration system through the raw material transfer pump 2 and the transfer pipeline. The filtration system is configured with a primary filter 3 and a secondary filter 4. The primary filter 3 and the secondary filter 4 can be used in series or in parallel. The types of the primary filter 3 and the secondary filter 4 are selected from one of a bag filter, a basket filter, a Y-type filter, a T-type filter, a security filter, a precision filter, etc., and the preferred type is a bag filter. After the waste phosphoric acid etching solution filters out suspended solid particles in the filtration system, it enters the phosphoric acid evaporation kettle 5. The phosphoric acid evaporation kettle 5 is heated by steam through the outer jacket of the phosphoric acid evaporation kettle 5. The steam volatilized from the phosphoric acid evaporation kettle 5 enters the evaporation condenser 9. After the steam is cooled by cooling water, the condensate enters the mixed acid storage tank 107. The liquid phase at the bottom of the phosphoric acid evaporation kettle 5 enters the phosphoric acid purification system 7 through the phosphoric acid semi-finished product transfer pump 6. The phosphoric acid purification system 7 is selected from one of an ion exchange resin complete set, an activated carbon adsorption complete set, a membrane filtration system complete set, a crystallization system complete set, etc., and the preferred is an ion exchange resin complete set. The semi-finished phosphoric acid removes impurities such as metal ions in the phosphoric acid purification system 7, and the resulting product is the finished product of electronic-grade phosphoric acid, and the product enters the phosphoric acid product storage tank 8.

[0053] The discharge of the mixed acid storage tank 10 enters the sodium acetate reaction kettle 12 through the mixed acid transfer pump 11. Sodium hydroxide is added to the sodium acetate reaction kettle 12 to carry out a neutralization reaction. The reaction process is cooled by cooling water, and the reaction product is a mixed solution of sodium acetate and nitric acid. The mixed solution enters the sodium acetate evaporator 14 through the reaction product transfer pump 13. The mixed solution is heated by steam to evaporate the nitric acid therein and concentrate the sodium acetate solution. The concentrated sodium acetate solution enters the sodium acetate crystallization kettle 16 through the sodium acetate concentrated solution transfer pump 15. The sodium acetate solution is cooled by cooling water and sodium acetate crystal particles are precipitated. The solid-liquid mixture containing sodium acetate crystal particles enters the sodium acetate product separator 18 through the crystal transfer pump 17 to separate out the solid sodium acetate product 32, and the remaining mother liquor 33 returns to the sodium acetate evaporator 14 for continuous concentration. The sodium acetate product separator 18 is selected from one of a filter press complete set and a centrifuge complete set, and the preferred is a centrifuge complete set. The gas volatilized from the top of the sodium acetate evaporator 14 is condensed by the nitric acid condenser 19, and the condensate enters the nitric acid product storage tank 20 as the nitric acid product.

[0054] In this embodiment, the phosphoric acid evaporation kettle 5 operates under negative pressure. The operating pressure of the phosphoric acid evaporation kettle 5 is 10 - 100 kPa (absolute pressure), and the evaporation temperature is 80 - 150 °C; the sodium acetate reaction kettle 12 and the sodium acetate crystallization kettle 16 operate under normal pressure; the sodium acetate evaporator 14 operates under negative pressure; the operating pressure of the sodium acetate evaporator 14 is 10 - 100 kPa (absolute pressure), and the evaporation temperature is 50 - 120 °C.

[0055] The device for recovering electronic-grade phosphoric acid from waste etching solution and its production process in this embodiment are configured with a raw material storage tank 1, a raw material delivery pump 2, a primary filter 3, a secondary filter 4, a phosphoric acid evaporation kettle 5, a semi-finished phosphoric acid delivery pump 6, a phosphoric acid purification system 7, a phosphoric acid product storage tank 8, an evaporation condenser 9, a mixed acid storage tank 10, a mixed acid delivery pump 11, a sodium acetate reaction kettle 12, a reaction product delivery pump 13, a sodium acetate evaporator 14, a sodium acetate concentrated solution delivery pump 15, a sodium acetate crystallization kettle 16, a crystal delivery pump 17, a sodium acetate product separator 18, a nitric acid condenser 19, and a nitric acid product storage tank 20. The raw material waste phosphoric acid etching solution separates suspended solid particles in the primary filter 3 and the secondary filter 4, and then separates phosphoric acid from nitric acid and acetic acid in the phosphoric acid evaporation kettle 5. Nitric acid and acetic acid volatilize and are condensed into a mixed acid of nitric acid and acetic acid by the evaporation condenser 9, and the mixed acid enters the mixed acid storage tank 10. The semi-finished phosphoric acid from which the miscellaneous acids are separated removes impurities such as metal ions like aluminum and molybdenum in the phosphoric acid purification system 7. The product after impurity removal is the finished product of electronic-grade phosphoric acid, and the product enters the phosphoric acid product storage tank 8. The mixed acid reacts with sodium hydroxide 25 to generate a mixed solution of sodium acetate and nitric acid. The mixed solution is evaporated and concentrated using steam. After the concentrated solution is cooled, sodium acetate crystal particles precipitate, and then solid sodium acetate product 32 is obtained through the product separator 18. The gas volatilized during the evaporation of the mixed solution is condensed to obtain nitric acid product. The separated suspended solid particles, metal ions and other impurities are further processed by incineration. This device and production process recover phosphoric acid in the waste etching solution by adopting systems such as negative pressure evaporation, neutralization reaction, cooling crystallization, solid-liquid separation, filtration, and purification, produce electronic-grade phosphoric acid products and by-products of sodium acetate and nitric acid products, which not only recovers the effective resources in the waste phosphoric acid etching solution but also reduces the emission of pollutants.

[0056] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combinations of these technical features do not conflict, they should all be considered as the scope recorded in this specification.

[0057] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A production device for recovering electronic grade phosphoric acid from waste etching liquid, comprising a raw material storage tank, a raw material delivery pump, a primary filter, a secondary filter, a phosphoric acid evaporator, a phosphoric acid semi-finished product delivery pump, a phosphoric acid purification system, a phosphoric acid product storage tank, an evaporation condenser, a mixed acid storage tank, a mixed acid delivery pump, a sodium acetate reactor, a reaction product delivery pump, a sodium acetate evaporator, a sodium acetate concentrate delivery pump, a sodium acetate crystallization reactor, a crystal delivery pump, a sodium acetate product separator, a nitric acid condenser, and a nitric acid product storage tank, characterized in that: The outlet of the raw material storage tank is connected to the inlet of the raw material delivery pump through a pipeline, and the raw material delivery pump is connected to the filtering system.

2. The production device for recovering electronic grade phosphoric acid from waste etching solution according to claim 1, characterized in that: The filtration system comprises a primary filter and a secondary filter; the primary filter and the secondary filter can be used in series or in parallel; The primary filter and the secondary filter are of the type of bag filter, basket filter, Y-type filter, T-type filter, security filter, precision filter, etc. Optionally, the primary filter and the secondary filter are of the type of bag filter.

3. The production device for recovering electronic grade phosphoric acid from waste etching solution according to claim 2, characterized in that: It also includes a phosphoric acid evaporator, a phosphoric acid semi-finished product delivery pump, a phosphoric acid purification system, and a phosphoric acid product storage tank; among which, The filtration system is connected to the liquid phase inlet of the phosphoric acid evaporator; the liquid phase outlet at the bottom of the phosphoric acid evaporator is connected to the inlet of the phosphoric acid semi-finished product delivery pump, the outlet of the phosphoric acid semi-finished product delivery pump is connected to the phosphoric acid purification system, and the phosphoric acid purification system is connected to the phosphoric acid product storage tank; The phosphoric acid purification system is one of an ion exchange resin complete set, an activated carbon adsorption complete set, a membrane filtration system complete set, and a crystallization system complete set, preferably an ion exchange resin complete set; The outer jacket of the phosphoric acid evaporator is also connected with a steam inlet and a steam condensed water outlet.

4. The production device for recovering electronic grade phosphoric acid from waste etching solution according to claim 3, characterized in that: It also includes an evaporative condenser and a mixed acid storage tank; the gas phase outlet at the top of the phosphoric acid evaporator is connected to the gas phase inlet of the evaporative condenser through a pipeline; the liquid phase outlet of the evaporative condenser is connected to the mixed acid storage tank through a pipeline.

5. The production device for recovering electronic grade phosphoric acid from waste etching solution according to claim 4, characterized in that: It also includes a mixed acid delivery pump, a sodium acetate reactor, a reaction product delivery pump, a sodium acetate evaporator, a sodium acetate concentrate delivery pump, and a sodium acetate crystallization reactor; wherein, The outlet of the mixed acid storage tank is connected to the inlet of the mixed acid delivery pump; the outlet of the mixed acid delivery pump is connected to the material inlet of the sodium acetate reactor, the material outlet of the sodium acetate reactor, the inlet of the reaction product delivery pump, the outlet of the reaction product delivery pump, the material inlet of the sodium acetate evaporator, the material outlet of the sodium acetate evaporator, the inlet of the sodium acetate concentrate delivery pump, the outlet of the sodium acetate concentrate delivery pump, and the material inlet of the sodium acetate crystallization kettle in sequence through pipelines; The top of the sodium acetate reactor is also connected to a sodium hydroxide feed port; the outer jacket of the sodium acetate reactor is also connected to a cooling water inlet and a cooling water outlet; The outer jacket of the sodium acetate evaporator is also connected to a steam inlet and a steam condensed water outlet; The outer jacket of the sodium acetate crystallization kettle is also connected with a cooling water inlet and a cooling water outlet.

6. The production device for recovering electronic grade phosphoric acid from waste etching solution according to claim 5, characterized in that: It also includes a crystal delivery pump and a sodium acetate product separator; the crystal delivery pump inlet is connected to the sodium acetate crystallization kettle material outlet, the crystal delivery pump outlet is connected to the sodium acetate product separator, the sodium acetate product separator liquid phase outlet is connected to the sodium acetate evaporator mother liquor inlet, and the sodium acetate product separator is also connected to a sodium acetate product discharge port; The sodium acetate product separator is one of a filter press complete set and a centrifuge complete set, preferably a centrifuge complete set.

7. The production device for recovering electronic grade phosphoric acid from waste etching solution according to claim 6, characterized in that: It also includes a nitric acid condenser and a nitric acid product storage tank; the gas phase outlet at the top of the sodium acetate evaporator is connected to the gas phase inlet of the nitric acid condenser through a pipeline; the liquid phase outlet of the nitric acid condenser is connected to the nitric acid product storage tank through a pipeline.

8. An electronic grade phosphoric acid recovery production process, characterized in that: The production is carried out using a production device for recovering electronic grade phosphoric acid from waste etching liquid according to any one of claims 1 to 7.

9. The production process for recovering electronic grade phosphoric acid from waste etching solution as claimed in claim 8, characterized in that: The phosphoric acid evaporator is operated under negative pressure; the operating pressure of the phosphoric acid evaporator is 10-100 kPa (absolute pressure), and the evaporation temperature is 80-150°C; the sodium acetate reaction kettle and the sodium acetate crystallization kettle are operated under normal pressure; the sodium acetate evaporator is operated under negative pressure; the operating pressure of the sodium acetate evaporator is 10-100 kPa (absolute pressure), and the evaporation temperature is 50-120°C.

10. The production process for recovering electronic grade phosphoric acid from waste phosphoric acid etching solution according to claim 9, characterized in that: The production process specifically comprises the following steps: The waste phosphoric acid etching liquid from the raw material storage tank enters the filtration system through the raw material delivery pump and the delivery pipeline. The filtration system is equipped with a primary filter and a secondary filter. The primary filter and the secondary filter can be used in series or in parallel. The primary filter and the secondary filter are selected from one of the bag filter, basket filter, Y-type filter, T-type filter, security filter, precision filter, etc., and the preferred type is a bag filter. After the waste phosphoric acid etching liquid is filtered out of suspended solid particles in the filtration system, it enters the phosphoric acid evaporator. The phosphoric acid evaporator is heated by steam through the outer jacket of the phosphoric acid evaporator. The steam volatilized from the phosphoric acid evaporator enters the evaporation condenser. After the steam is cooled by cooling water, the condensate enters the mixed acid storage tank. The liquid phase at the bottom of the phosphoric acid evaporator enters the phosphoric acid purification system through the phosphoric acid semi-finished product delivery pump. The phosphoric acid purification system uses one of the ion exchange resin complete set, activated carbon adsorption complete set, membrane filtration system complete set, and crystallization system complete set. The ion exchange resin complete set is preferred. The semi-finished phosphoric acid removes impurities such as metal ions in the phosphoric acid purification system, and the resulting product is an electronic grade phosphoric acid product, which enters the phosphoric acid product storage tank; and The discharge of the mixed acid storage tank enters the sodium acetate reactor through the mixed acid delivery pump, and sodium hydroxide is added to the sodium acetate reactor for neutralization reaction. The reaction process is cooled by cooling water, and the reaction product is a mixed solution of sodium acetate and nitric acid. The mixed solution enters the sodium acetate evaporator through the reaction product delivery pump, and the mixed solution is heated by steam to evaporate the nitric acid therein and concentrate the sodium acetate solution. The concentrated sodium acetate solution enters the sodium acetate crystallization kettle through the sodium acetate concentrate delivery pump, and the sodium acetate solution is cooled by cooling water and sodium acetate crystal particles are precipitated. The solid-liquid mixture containing sodium acetate crystal particles enters the sodium acetate product separator through the crystal delivery pump to separate the solid sodium acetate product, and the remaining mother liquor returns to the sodium acetate evaporator for further concentration. The sodium acetate product separator selects one of the filter press complete set and the centrifuge complete set, preferably the centrifuge complete set. The gas volatilized from the top of the sodium acetate evaporator is condensed through the nitric acid condenser, and the condensate enters the nitric acid product storage tank as the nitric acid product.

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