A method for preparing high purity halide wet electronic chemicals by sub-boiling distillation
By employing sub-boiling distillation and multi-stage falling film absorption technology, the problems of low recovery rate and high energy consumption in the preparation of high-purity halides have been solved, achieving efficient and low-cost preparation of high-purity halides with stable product quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANDONG HUAYU TONGFANG ELECTRONIC MATERIALS CO LTD
- Filing Date
- 2024-04-25
- Publication Date
- 2026-06-12
AI Technical Summary
Existing methods for preparing high-purity halides suffer from low recovery rates, high energy consumption, and large equipment investments. Furthermore, the lack of vaporization of liquid droplets during distillation leads to a decline in product quality.
Using sub-boiling distillation, high-pressure liquefied halides are used as raw materials. High-purity halide wet electronic chemicals are prepared by combining sub-boiling distillation and multi-stage falling film absorbers with ultrapure water absorption. This method avoids liquid droplets entering the gas phase, improves recovery rate and reduces energy consumption.
It significantly improves the recovery rate of halides to over 80%, reduces energy consumption and equipment investment, and at the same time ensures the high purity and stability of the product.
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Figure CN118183628B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of wet electronic chemicals technology, specifically relating to a method for preparing high-purity halide wet electronic chemicals using sub-boiling distillation. Background Technology
[0002] High-purity halides are a common class of wet electronic chemicals, generally including hydrobromic acid, hydrochloric acid, and hydrofluoric acid. They are mainly used in the cleaning process of integrated circuit manufacturing to remove various metals, organic matter, and particulate matter. Integrated circuits have high purity requirements for wet electronic chemicals, generally at G3 or higher. The larger the wafer size, the higher the purity requirement; 12-inch wafer manufacturing generally requires a purity level of G4 or higher. Therefore, G4 and G5 grade high-purity halides place higher demands on the preparation methods.
[0003] Currently, the commonly used method for purifying high-purity halides involves retrieving the gaseous halide from an aqueous halide solution, followed by filtration, dehydration, drying, and then absorption with ultrapure water. For example, the preparation of electronic chemical-grade hydrochloric acid uses 31% industrial-grade hydrochloric acid. This is achieved by countercurrent contact of the hydrochloric acid with steam and heating to release hydrogen chloride gas. The hydrochloric acid concentration in the eluent is approximately 20%, at which point the halide forms an azeotrope with water, preventing further hydrochloric acid retrieving. However, this method only yields about 10% of the hydrochloric acid, resulting in a utilization rate of only about 30%. Furthermore, retrieving one ton of hydrochloric acid requires 1.65 tons of steam, leading to high energy consumption. Companies with the necessary resources utilize the azeotropic acid after retrieving to absorb hydrogen chloride, while those without such resources typically employ salt distillation (e.g., calcium chloride) for deeper retrieving. Although salt distillation yields a higher single-pass hydrogen chloride recovery rate, the cost of concentrating the calcium chloride solution is significantly higher. Furthermore, the hydrochloric acid stripping tower is made entirely of graphite, and the stripped hydrogen chloride gas contains 100 ppm of water, requiring further processing such as filtration and sulfuric acid drying, resulting in significant equipment investment. Therefore, current methods for preparing high-purity halides suffer from drawbacks such as low recovery rates, high energy consumption, and substantial equipment investment.
[0004] Furthermore, typical distillation operations require the liquid to be in a state of vigorous boiling, forming an aerosol in the distillation vessel. This aerosol contains gaseous particles suspended in the distillate droplets. This aerosol either enters the condenser or is absorbed by water and enters the product. Because these droplets are not vaporized and purified, they still contain a certain amount of various impurities, thus contaminating the quality of the distillate and reducing the quality of the high-purity halides. Summary of the Invention
[0005] In order to obtain high-purity halide wet electronic chemicals, this application provides a new method for preparing high-purity halide wet electronic chemicals.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A method for preparing high-purity halide wet electronic chemicals using near-subboiling distillation includes the following steps:
[0008] (1) Industrial-grade liquid hydrogen halide (≥5.5N) is fed from the lower part of the sub-boiling still, and circulating water at 25°C is used as a heat source to enter the outer heating jacket of the sub-boiling still; the industrial-grade liquid hydrogen halide is in a sub-boiling state in the sub-boiling still, and the liquid hydrogen halide will not rise along the wall of the still. The hydrogen halide gas is discharged from the top of the sub-boiling still and enters the first-stage falling film absorber after depressurization; the residual material is discharged from the bottom of the sub-boiling still.
[0009] (2) The hydrogen chloride gas that is not absorbed by the first-stage falling film absorber enters the second-stage falling film absorber and the absorption tower in sequence; the hydrogen halide solution discharged from the bottom of the first-stage falling film absorber enters the first-stage absorption tank, and the hydrogen halide in the absorption tank is used as a circulating absorbent to enter the top of the first-stage falling film absorber through the first-stage circulating pump until the mass concentration of the hydrogen halide solution reaches the requirements of electronic-grade hydrogen halide and the circulation stops to obtain electronic-grade hydrogen halide.
[0010] The temperature of the circulating absorbent at each stage is lower than the vaporization temperature of liquid hydrogen halide.
[0011] Furthermore, the liquid level in the sub-boiling still is 50%-80%, the pressure in the sub-boiling still is 38-39 barG, and the upward flow rate of hydrogen chloride gas in the sub-boiling still is 3-6 m / h.
[0012] The vaporization temperature of halides is pressure-dependent; for example, hydrogen chloride at 38 bar G has a vaporization temperature of 17°C. Circulating water at 25°C is used for jacket heating, and the flow rate of the circulating water is determined based on the production output to ensure an upward airflow rate of 3-6 m / h.
[0013] Furthermore, the liquid level in the sub-boiling still is 60%, the pressure in the sub-boiling still is 38 barG, and the upward flow rate of hydrogen chloride gas in the sub-boiling still is 3 m / h.
[0014] Furthermore, the unabsorbed hydrogen chloride gas in the secondary falling film absorber is discharged and enters the absorption tower, while the hydrogen halide solution discharged from the bottom of the secondary falling film absorber enters the secondary absorption tank. The hydrogen halide in the absorption tank is used as a circulating absorbent and enters the top of the secondary falling film absorber through the secondary circulation pump.
[0015] Furthermore, the hydrogen halide solution discharged from the bottom of the absorber is used as a circulating absorbent and enters the top of the absorber via a three-stage circulating pump.
[0016] Preferably, the hydrogen halide is hydrogen chloride, hydrogen fluoride, or hydrogen bromide.
[0017] Preferably, the hydrogen halide is hydrogen chloride, the mass concentration of the electronic grade hydrogen chloride solution is 37%, and the content of impurity metal ions does not exceed 10 ppt.
[0018] Furthermore, a portion of the hydrogen halide solution in the secondary absorption tank is circulated and absorbed at the top of the secondary falling film absorber via a secondary circulation pump. When the concentration reaches 22-25%, a portion of the hydrogen halide solution is transferred into the primary absorption tank.
[0019] Furthermore, a portion of the hydrogen halide solution discharged from the bottom of the absorption tower is circulated back into the top of the absorption tower via a three-stage circulation pump. When the absorption concentration reaches 14-17%, a portion of the hydrogen halide solution is transferred to the secondary absorption tank.
[0020] Furthermore, the cooling water supplied to the shell side of the primary and secondary falling film absorbers is 7°C, and the absorption temperature of the primary and secondary falling film absorbers is below 20°C.
[0021] Furthermore, a cooler is installed after the absorption tower circulation pump.
[0022] Compared with the prior art, the present invention has the following advantages:
[0023] This application uses high-pressure liquefied halides as raw materials, which are then purified again through near-sub-boiling distillation and absorbed with ultrapure water to prepare the final product. This process features significantly high recovery rates, low equipment investment, a short process, and more stable quality. The purified halides used as raw materials are typically high-pressure liquefied hydrogen halides, which are anhydrous and non-corrosive to equipment.
[0024] Taking hydrogen chloride as an example, the single-pass recovery rate of sub-boiling distillation is close to 80% or more. Sub-boiling distillation evaporates high-pressure liquefied hydrogen chloride, whose heat capacity is about 0.3 times that of water, resulting in very low energy consumption during the evaporation process. Since the boiling point of hydrogen chloride at room temperature is only about 20°C, 25°C circulating water can be used as the heat medium for sub-boiling distillation. The 25°C circulating water acts as a heat source entering the heating jacket outside the sub-boiling still. The halides do not directly contact the heat source in the sub-boiling still; heat is conducted through the jacket wall of the sub-boiling still, achieving the distillation of hydrogen halide gas. The required amount of hot water is only 0.3 times that of hydrochloric acid, resulting in low heat source temperature, low consumption, and low energy consumption. The internal temperature of the sub-boiling still is lower than the boiling point of liquefied hydrogen chloride. The liquid phase does not boil, and no gaseous suspension is produced as in normal boiling. The distilled hydrogen chloride gas does not contain gaseous suspension, preventing unvaporized hydrogen chloride droplets from being carried into the gas phase.
[0025] The high-purity hydrogen chloride from the refining tower reflux tank enters the sub-boiling still. 80% of the hydrogen chloride is depressurized by the pressure reducing valve and enters the lower end of the first-stage falling film absorber, where it comes into countercurrent contact with dilute hydrochloric acid from the second-stage falling film absorber. Unabsorbed hydrogen chloride enters the lower end of the second-stage absorber, where it comes into countercurrent contact with dilute hydrochloric acid from the absorber. Still unabsorbed hydrogen chloride enters the bottom of the absorber from the top of the second-stage falling film absorber, where it is absorbed by ultrapure water from the outside environment. The non-condensable gas enters the tail gas treatment unit. 20% of the hydrogen chloride from the bottom of the tower enters the industrial-grade hydrogen chloride filling unit. The unit achieves a single-cycle hydrogen chloride recovery rate of 80%. Attached Figure Description
[0026] Figure 1 This is the process flow diagram of Example 1.
[0027] In the diagram, 1. Sub-boiling still; 2. Primary falling film absorber; 3. Primary absorption tank; 4. Primary circulating pump; 5. Secondary falling film absorber; 6. Secondary absorption tank; 7. Secondary circulating pump; 8. Absorption tower; 9. Tertiary circulating pump; 10. Cooler; 11. Tail gas treatment device. Detailed Implementation
[0028] Example 1
[0029] Taking the preparation of high-purity hydrochloric acid as an example, Figure 1 The apparatus shown prepares a wet electrolytic chemical hydrochloric acid solution. This equipment uses a sub-boiling still to extract hydrogen chloride gas. The apparatus includes a sub-boiling still 1, whose top outlet is sequentially connected to a primary falling film absorber 2, a primary absorption tank 3, and a primary circulation pump 4. The top gas outlet of the primary falling film absorber 2 is sequentially connected to a secondary falling film absorber 5, a secondary absorption tank 6, and a secondary circulation pump 7. The top gas outlet of the secondary falling film absorber 5 is connected to an absorption tower 8, which is equipped with a tertiary circulation pump 9. Cooling water at 7°C is introduced into the shell side of the primary falling film absorber 2 and the secondary falling film absorber 5, and the absorption temperature of the primary falling film absorber 2 and the secondary falling film absorber 5 is below 20°C.
[0030] The sub-boiling still 1 includes a column body, and a heating jacket is provided in the middle and lower part of the column body. Circulating water at 25°C enters the heating jacket outside the sub-boiling still 1 as a heat source to heat the liquefied hydrogen chloride inside the column body, so that it is in a sub-boiling state. The hydrogen chloride gas without liquid droplets is distilled out and absorbed by ultrapure water to form high-purity hydrochloric acid.
[0031] Specifically, it includes the following steps:
[0032] (1) Taking high-purity hydrochloric acid as an example, the purified liquefied hydrogen chloride is introduced below the liquid surface of the sub-boiling still. The liquid level in the sub-boiling still is controlled to be 50%-80%, preferably 60%. Circulating water at 25°C is used as a heat source to enter the outer heating jacket of the sub-boiling still 1. The pressure in the sub-boiling still is 38 barG. The heating rate in the sub-boiling still 1 ensures that the gas velocity in the column is 3 m / s and the temperature in the column is 18-19°C, so that the liquefied hydrogen chloride is in a sub-boiling state in the sub-boiling still 1. The hydrogen chloride gas without liquid droplets is discharged from the top of the sub-boiling still 1 and enters the first-stage falling film absorber 2 after depressurization. The remaining hydrochloric acid aqueous solution with a mass concentration of 20% is discharged from the bottom of the sub-boiling still 1 and then enters the industrial-grade hydrogen chloride filling unit.
[0033] (2) The hydrogen chloride gas entering the first-stage falling film absorber 2 is partially absorbed by ultrapure water below 20°C, forming an electronic-grade hydrochloric acid solution which then enters the first-stage absorption tank 3. The unabsorbed hydrogen chloride gas is discharged from the top and enters the second-stage falling film absorber 5. After the hydrochloric acid solution in the first-stage absorption tank 3 is cooled, it is used as a circulating absorbent and enters the top of the first-stage falling film absorber 2 through the first-stage circulating pump 4. When the hydrochloric acid solution in the first-stage absorption tank 3 reaches 36%-38%, the electronic-grade hydrochloric acid in the first-stage absorption tank 3 is transported to the filling system. The content of each impurity in the electronic-grade hydrochloric acid is G5 grade high-purity hydrochloric acid, and the various metal ion impurities do not exceed 10ppt.
[0034] (3) The hydrogen chloride gas entering the secondary falling film absorber 5 is partially absorbed by the circulating absorbent liquid below 20°C, forming a hydrochloric acid solution which then enters the secondary absorption tank 6. The unabsorbed hydrogen chloride gas is discharged from the top and enters the bottom of the absorption tower 8. Part of the hydrochloric acid solution in the secondary absorption tank 6 enters the top of the secondary falling film absorber 5 through the secondary circulation pump 7. When the mass concentration of the hydrochloric acid solution reaches 20%-25%, part of it is circulated to the primary absorption tank 3, mixed with the hydrochloric acid discharged from the bottom of the primary falling film absorber 2, and then circulated to the primary falling film absorber.
[0035] (4) The unabsorbed hydrogen chloride gas continues to be absorbed in the absorption tower 8 by countercurrent contact with ultrapure water or circulating absorbent. The low-concentration hydrochloric acid formed in the bottom of the tower is cooled by the cooler 10 and then circulated to the top of the absorption tower as circulating absorbent. When the mass concentration of the low-concentration hydrochloric acid reaches 5%-10%, part of it is circulated to the secondary absorption tank 6 and mixed with the hydrochloric acid discharged from the bottom of the secondary falling film absorber 5 as circulating absorbent, and then circulated to the secondary falling film absorber 6. The hydrogen chloride gas discharged from the top of the absorption tower 8 is sent to the alkaline washing process or the tail gas treatment device 11.
[0036] Meanwhile, the absorbent in this application is circulated within the absorption tower, the secondary falling film absorber, and the primary falling film absorber, which can effectively reduce the use of ultrapure water, reduce the amount of absorbent used directly, and lower production costs.
[0037] In the above process, the high-purity hydrogen chloride refining tower reflux tank receives the raw material, which then enters the sub-boiling still. In the sub-boiling still, 80% of the hydrogen chloride is depressurized and vaporized after passing through the pressure reducing valve, entering the lower end of the first-stage falling film absorber, where it comes into countercurrent contact with dilute hydrochloric acid from the second-stage falling film absorber. Unabsorbed hydrogen chloride enters the lower end of the second-stage absorber, where it comes into countercurrent contact with dilute hydrochloric acid from the absorber. Still unabsorbed hydrogen chloride enters the bottom of the absorber from the top of the second-stage falling film absorber, where it is absorbed by ultrapure water from the outside environment. The non-condensable gas then enters the tail gas treatment unit. Simultaneously, while 80% of the hydrogen chloride is depressurized and vaporized into the falling film absorber, 20% of the high-pressure liquid-phase hydrogen chloride in the sub-boiling still enters the industrial-grade hydrogen chloride filling unit. Therefore, the hydrogen chloride recovery rate in the high-purity hydrochloric acid preparation process is 80%. As the vaporization rate increases, heavy components become enriched in the liquid phase of the still; therefore, the higher the recovery rate, the higher the content of heavy components entering the high-purity hydrochloric acid. Conversely, to control heavy components such as metal ion impurities, the recovery rate needs to be controlled within a reasonable range.
[0038] Example 2
[0039] A method for preparing wet electronic chemical hydrochloric acid using sub-boiling distillation differs from Example 1 in that the liquid level and / or pressure and / or heating rate in the sub-boiling still are different, and the specific parameters are shown in Table 1.
[0040]
[0041] As can be seen from Table 1, under the same operating pressure, the higher the liquid level in the sub-boiling still, the greater the gas phase velocity, the higher the recovery rate, and the higher the content of metal ion impurities.
Claims
1. A method for preparing high-purity halide wet electronic chemicals using sub-boiling distillation, characterized in that, Includes the following steps: (1) Industrial-grade liquid hydrogen halide is fed from the lower part of the sub-boiling still, and circulating water at 25°C is used as a heat source to enter the outer heating jacket of the sub-boiling still; the industrial-grade liquid hydrogen halide is in a sub-boiling state in the sub-boiling still, and the liquid hydrogen halide will not rise along the wall of the still. The hydrogen halide gas is discharged from the top of the sub-boiling still and enters the first-stage falling film absorber after depressurization; the residual material is discharged from the bottom of the sub-boiling still; the liquid level in the sub-boiling still is 50%-80%, the pressure in the sub-boiling still is 38 barg-39 barg, and the upward flow rate of hydrogen chloride gas in the sub-boiling still is 3-6 m / h; (2) The hydrogen chloride gas that is not absorbed by the first-stage falling film absorber enters the second-stage falling film absorber and the absorption tower in sequence; the hydrogen halide solution discharged from the bottom of the first-stage falling film absorber enters the first-stage absorption tank, and the hydrogen halide in the absorption tank is used as a circulating absorbent to enter the top of the first-stage falling film absorber through the first-stage circulating pump until the mass concentration of the hydrogen halide solution reaches the requirements of electronic-grade hydrogen halide and the circulation stops to obtain electronic-grade hydrogen halide. Unabsorbed hydrogen chloride gas in the secondary falling film absorber is discharged and enters the absorption tower. Hydrogen halide solution discharged from the bottom of the secondary falling film absorber enters the secondary absorption tank. Hydrogen halide in the absorption tank is used as circulating absorbent and enters the top of the secondary falling film absorber through the secondary circulation pump. The hydrogen halide is hydrogen chloride, and the mass concentration of the electronic grade hydrogen chloride solution is 37%, with the impurity metal ion content not exceeding 10 ppt. The temperature of the circulating absorbent at each stage is lower than the vaporization temperature of liquid hydrogen halide.
2. The method for preparing high-purity halide wet electronic chemicals by sub-boiling distillation according to claim 1, characterized in that, The hydrogen halide solution discharged from the bottom of the absorption tower is used as a circulating absorbent and enters the top of the absorption tower through a three-stage circulating pump.
3. The method for preparing high-purity halide wet electronic chemicals using sub-boiling distillation according to claim 2, characterized in that, A portion of the hydrogen halide solution in the secondary absorption tank is circulated and absorbed at the top of the secondary falling film absorber via a secondary circulation pump. When the concentration reaches 22-25%, a portion of the hydrogen halide solution is transferred into the primary absorption tank.
4. The method for preparing high-purity halide wet electronic chemicals by sub-boiling distillation according to claim 3, characterized in that, A portion of the hydrogen halide solution discharged from the bottom of the absorption tower is circulated back into the top of the absorption tower via a three-stage circulation pump. When the absorption concentration reaches 14-17%, a portion of the hydrogen halide solution is transferred into the secondary absorption tank.
5. The method for preparing high-purity halide wet electronic chemicals by sub-boiling distillation according to claim 1, characterized in that, The cooling water supplied to the shell side of the primary and secondary falling film absorbers is 7°C, and the absorption temperature of the primary and secondary falling film absorbers is below 20°C.
6. The method for preparing high-purity halide wet electronic chemicals by sub-boiling distillation according to claim 1, characterized in that, A cooler is installed after the circulating pump of the absorption tower.