JP2023524919A - Separation and purification method for refining industrial-level high-concentration HF to electronic-level FTrPSA - Google Patents

Abstract

Kind Code: A1 AHF refining is subject to phase equilibrium limitations in separation processes such as traditional rectification, distillation, absorption or chemisorption, or has a short adsorbent service life. The present invention discloses a separation and purification method for purifying industrial-level high-concentration HF to electronic-level FTrPSA, wherein each fraction in industrial-level AHF (gas) (HF is the active fraction H2O, H2SO4, SO2, SiF4, NH3, CO2, H2SiF6 and traces of HCl, water-soluble Me+ ions and SS particles as the main impurity fractions) themselves can be adsorbed/rectified/membrane under different pressures and temperatures. Using the difference of separation factor and physico-chemical properties, it mainly adopts two-stage medium-temperature pressure-pressure adsorption process, and combines HF with rectification/membrane separation, so that the adsorption and desorption in the medium-temperature pressure-pressure adsorption process are consistent. By facilitating separation and purification by repeated operations of chemistry and equilibrium, the manufacture of electronic-level HF products is realized. The present invention has filled a void in the technical field by solving the above problems. [Selection drawing] Fig. 1

Description

The present invention is a creation related to purification and purification for preparing electronic-level HF using industrial-level high-concentration hydrogen fluoride (HF) as a raw material. More specifically, the invention relates to a separation and purification process for refining industrial-grade high-concentration HF to electronic-level FTrPSA (full-temperature pressure-pressure adsorption).

Hydrogen fluoride (HF) is a basic raw material in fluorine chemistry, and can be used in the production of organic fluorine, inorganic fluoride salts and other fluorine-containing catalysts, fluorosilicic acid and other fields. HF is increasingly being applied in the field of organic fluorine, such as refrigerants, surfactants, fluororubbers, fluorocoatings, fluororesins, fluorochemicals, high-purity fluororesins, and pharmaceutical intermediates. At present, with the development of the semiconductor industry, ultra-pure electronic level HF (gas and liquid) has been widely applied in wafer cleaning, etching and chemical vapor deposition processes of integrated circuits (IC) and very large scale integrated circuits (VLSI). It is one of the key basic chemical materials in the manufacturing process of the microelectronics industry. It can also be used as an analytical reagent to prepare high-purity fluorine-containing chemicals and semiconductor materials.

At present, the industrial preparation and extraction of high-purity HF mainly takes industrial-level high-concentration HF as raw material, and adopts distillation/rectification and membrane separation as the main purification methods. Including sub-boiling distillation, vacuum distillation, gas absorption, microfilter, ultrafiltration, nanofiltration and various configurations. In these traditional purification processes, the difference in volatility (boiling point), solubility or molecular size at different temperatures between each fraction of the feedstock (liquid/gas) and HF is used to By separating, purifying and removing the impurities inside, a non-aqueous HF (AHF) product corresponding to the purity can be obtained. The major impurity fractions in the feedstock are fluorosilicic acid ( _H2SiF6 ), water ( _H2O ), chlorides (mainly _hydrogen chloride HCl), phosphides (P), metal oxides (MeO), metal ions and solid granules (SS); Electronic level HF products are classified into EL (general electronic level), UP (ultra pure), UPS (ultra high purity), and UPSS (ultra high purity). Establish a standard corresponding to the S level, which corresponds to the UPS/UPSS level. For example, the UP electronic level HF (liquid) index commonly used in China is _H SiF ₆ content is less than 100 ppm, chloride (Cl) is less than 5 ppm, P is less than 1 ppm, Standards such as MeO/Me+ less than 10 ppb and SS (≧1 μm) less than 25 units/ml. MeO/Me+ are MeO/Me+ impurities, especially water-soluble arsenic (As), magnesium (Mg), calcium (Ca), sodium (Na) and potassium (K), and must be removed cleanly. . Otherwise, the performance of the semiconductor wafer will be severely impacted. Electronic level HF liquids as semiconductor wafer cleaners or wet etches have varying levels of HF content, such as 49%, with the remainder being deionized water. Therefore, industrially, the fluorite method and the fluorosilicic acid method are usually adopted, and the purity is 99.9% after rectification and membrane filtration in the production process of preparing non-aqueous HF (AHF). A pure AHF gas is obtained. After absorption with deionized water, the method of controlling the shower density, gas-liquid ratio and membrane filtration can be adopted to further purify the electronic level hydrofluoric acid to obtain the electronic level HF liquid product. However, during the rectification process water, HF and other impurities produced from the fluorite or fluorosilicic acid process itself, such as sulfuric acid ( _H2SO4 ), sulfur dioxide ( _SO2 ), hydrogen _chloride (HCl ), silicon tetrafluoride (SiF ₄ ), ammonia (NH ₃ ) and carbon dioxide (CO ₂ ), etc., and due to the phase equilibrium constraints imposed by the rectification separation, these impurities are completely separated from HF. Since the pure AHF gas obtained still contains a relatively large number of impurity fractions, it can be used for subsequent deionized water absorption, control of shower density and gas-liquid ratio, membrane filtration, etc. It is also very difficult to remove traces or traces of impurity fractions by these subsequent purifications in the process of . Therefore, it is extremely important to control the purity of the pure AHF commercial obtained during the production process of preparing AHF from the fluorite method and the fluorosilicic acid method. Therefore, if the technical level HF or AHF feed gas with a content of 95-99% is directly subjected to rectification, distillation, sub-distillation or special rectification, the impurity concentration is too low, and the cost of rectification or distillation is very high. . Although the difference in boiling points between the impurity fraction and HF is relatively large, rectification or distillation imposes severe limits on the phase equilibrium because water affects the mass transfer distribution of each other impurity fraction in water. However, the purification depth falls far short of electronic level requirements.

It has been reported that HF can be purified by adopting an adsorption method, and the adsorbent is mainly an alkaline metal fluoride, and the metal fluoride and HF utilize a chemical reaction that occurs at a relatively low temperature. , selectively chemisorbs to form a metal fluoride-HF complex. Desorption of the complex from the adsorbent can be achieved by carrying out the decomposition reaction of the complex at a relatively high temperature in order to desorb HF from the adsorbent. separation and purification can be achieved. In most of the process situations where this chemisorption method is applied, commodities such as fluorochloroalkanes (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons ( _HFCs ), and sulfuryl fluoride ( _SO2F2 ) are produced by fluorination reactions. and the reaction mixture gas produced by the reaction can selectively adsorb, separate and recover HF, so the effect is better, but the loss rate of the adsorbent is large. For crude HF or pure HF obtained by the fluorite method or the fluorosilicic acid method containing water, sulfuric acid, _SiF4, etc., the adsorbent is powdered by chemical reaction with the fraction of impurities such as water. , and the effect of the adsorbent is significantly lost, making it impossible to effectively remove impurities by deep dehydration. Of particular importance, any alkaline metals or metal ions on the adsorbent can chemically react with HF and be incorporated into the HF gas itself, making subsequent HF purification difficult. Therefore, the chemisorption method can hardly be effectively applied to the AHF process prepared by the fluorite method or the fluorosilicic acid method.

This is also one of the main reasons why China, our country, is currently only able to produce low-level electronic level AHF products. This is one of the important reasons why the export of electronic level AHF to South Korea was restricted due to its superiority. Japan is one of the very few countries that has the technology to prepare AHF with a purity of 99.9999%-99.99999999% (6N-12N) internationally.

SUMMARY OF THE INVENTION The object of the present invention is to provide a separation and purification method for refining industrial-level high-concentration HF to electronic-level FTrPSA (full-temperature pressure-pressure adsorption). Full Temperature Range-Pressure Swing Adsorption (abbreviated as FTrPSA) is a method that is based on pressure-pressure adsorption (PSA) and can be phase-coupled with various separation technologies. gas) in each fraction (HF is effective fraction H ₂ O, H ₂ SO ₄ , SO ₂ , SiF ₄ , NH ₃ , CO ₂ , H ₂ SiF ₆ and traces of HCl, water-soluble Me + ions and SS Particles as the main impurity fraction) itself, using the difference of adsorption/rectification/membrane separation coefficients and physicochemical properties under different pressures and temperatures, mainly adopts a two-step medium temperature pressure pressure adsorption process. By adopting and combining with HF and rectification/membrane separation, the adsorption and desorption in the medium temperature pressure pressure adsorption process can be easily separated and purified by repeated operations of consistency and equilibrium, so that the electronic level Realize the manufacture of HF products.

The technical idea adopted by the present invention is as follows.

In the separation and purification method for refining industrial-level high-concentration HF to electronic-level FTrPSA, the raw material gas is industrial-level produced in the non-aqueous hydrogen fluoride (AHF) production process prepared by the fluorite method or the fluorosilicic acid method. A gas of high concentration hydrogen fluoride (HF), HF with a concentration of 95-99% (v/v), and sulfuric acid (H ₂ SO ₄ ), water (H ₂ O), sulfur dioxide (SO ₂ ), Silicon tetrafluoride ( _SiF4 ), ammonia (NH3), fluorosilicic acid ( _H2SiF6 ), carbon dioxide ( _CO2 ), chloride (calculated with _HCl ), metal ions (Me+) and fine particles (SS) It is due to other impurity fractions, and Me + is mainly water-soluble sodium (Na), magnesium (Mg), calcium (Ca), and arsenic (As) ions, and the diameter of SS particles is 1 micrometer (μm ), the temperature is 20-60° C., the pressure is normal pressure or micro pressure, and includes the following steps.
(1) The raw material gas undergoes cold heat exchange between 50 and 80° C. and is pressurized to 0.2 to 0.3 MPa, and then enters a medium temperature pressure pressure adsorption process consisting of two-stage pressure pressure adsorption (PSA), Each stage pressure pressure adsorption is composed of at least two or more adsorption towers, at least one adsorption tower is in the adsorption process, and the remaining adsorption towers are reverse depressurization or evacuation, pressurization or final filling and other different stages of desorption. In the process, the feed gas enters from the bottom of the first stage PSA (1 ^# PSA) adsorption tower, the operating pressure of 1 ^# PSA is 0.2-0.3 MPa, the operating temperature is 50-80 ℃, The non-adsorbed phase gas flowing out from the top of the adsorption tower in the adsorption step is pure HF gas, and the non-condensed gas after condensation is precision filtered, and after absorbing deionized water, the concentration obtained is 40 to 49. % HF aqueous solution is exported as a general electronic EL level hydrofluoric acid commodity, and the pure HF formed after condensation enters the next process, membrane separation, into the 1 ^# PSA adsorption tower in the desorption process. The desorbed gas flowing out from the bottom of the tower is pressurized and subjected to cold heat exchange, and then enters the bottom of the adsorption tower of the second stage PSA (2 ^# PSA), and the operating pressure of the 2 ^# PSA adsorption tower is 0.2-0. .3 MPa, the operating temperature is 50-80° C., and the non-adsorbed phase intermediate gas flowing out from the top of the 2 ^# PSA adsorption tower in the adsorption process is mixed with the raw material gas and fed to the 1 ^# PSA adsorption tower. Returning, the desorbed gas flowing out from the bottom of the 2 ^# PSA adsorption tower is the enriched gas, and then enters the ammonia water decarburization process to recover the effective fraction, medium temperature pressure pressure adsorption.
(2) The pure HF liquid condensed and formed from the medium-temperature pressure-pressure adsorption step is pressurized to 1.0-1.6 MPa, the temperature is 50-80° C., and the inorganic Enter the ceramic membrane or stainless steel membrane separation system, the membrane pore size is less than 1 micrometer, the clarified pure HF liquid flows out from the permeated side of the membrane, and the content of SS particles with a diameter greater than 1 micrometer is 25 units. / milliliter (Ea/ml), enter the next step, HF rectification, concentrate the SS particle concentrate on the non-permeated side of the membrane, cool and precipitate, and then remove the SS particles. , membrane separation in which the liquid is heated and pressurized, then returned to the membrane separation system, and the effective fraction is recovered.
(3) The purified pure HF liquid from the membrane separation process enters the rectification column of the HF rectification process, and the rectification column in this process adopts the configuration of upper and lower two-stage rectification, and the purified pure HF liquid is The light end impurity gas that enters from the top of the lower rectification or the bottom of the upper rectification and is removed from the top of the upper rectification column returns to the subsequent exhaust gas absorption step, and enters the bottom of the upper rectification or the top of the lower rectification. The non-condensable gas formed after condensation of the distillate is AHF gas, the purity is greater than 99.99%, directly into the electronic UP or USP level AHF commodity gas, and the liquid formed after condensation is the upper or as a circulation stream of the lower rectification, the non-condensable gas formed after condensation of the bottom fluid of the impurity fraction containing a small amount of heavy fraction distilled from the bottom of the lower rectification is returned to the temperature pressure pressure adsorption step, HF rectification in which the effective fraction is recovered and the liquid formed after condensation is used as an absorbent for the next step, ammonia water decarburization.
(4) The concentrated gas from the medium-temperature pressure-pressure adsorption step, after being pressurized to normal pressure or a slight overpressure, into the liquid formed after condensation of aqueous ammonia, sulfuric acid and the rectified distillate from the lower stage of the HF rectification step. Ammonium hydrogen carbonate and ammonium hydrogen fluoride mixed solution formed from the bottom of the absorption tower is discharged from the absorption tower bottom, and AHF is directly used as a fluorosilicic acid method. Aqueous ammonia decarburization to prepare return or premixed reactants in the production process.

Further, the medium membrane separation system in step (2) can be a membrane module of microfilter membranes or ultrafiltration membranes.

Furthermore, the light fraction impurity gas distilled from the top of the upper rectification tower in the HF rectification process is mixed with the non-condensable gas from the top of the ammonia water decarburization absorption tower, and is exhausted using sulfuric acid as an absorbent. Entering the gas absorption tower, forming a fluorosilicic acid solution from the bottom of the absorption tower, discharging it as a raw material, can be directly returned to the raw material recycling use in the non-aqueous hydrogen fluoride AHF production process prepared by the fluorosilicic acid method, It also includes an exhaust gas absorption step in which the non-condensable gas flowing out from the top of the absorption tower is directly discharged as exhaust gas.

Furthermore, the adsorption tower in the medium temperature pressure pressure adsorption step is loaded with activated aluminum oxide, silica gel and molecular sieve, and the weight of aluminum oxide: silica gel: molecular sieve in the adsorbent composition loaded in the 1 ^# PSA adsorption tower The ratio is (4-6):(2-4):(1-3) and the weight ratio of aluminum oxide: silica gel: molecular sieve in the adsorbent composition loaded in the 2 ^# PSA adsorption tower is (3-5). :(1-3):(3-5).

The loading quantity and distribution of the three kinds of adsorbents are determined by the raw gas HF concentration and the content of impurity fractions, and the loading quantity distribution of the adsorbents in the two-stage PSA adsorption tower is also different.

Furthermore, in exhaust gas absorption, the light fraction impurity gas distilled from the top of the upper rectification tower in the HF rectification process is mixed with the non-condensable gas from the top of the ammonia water decarburization absorption tower to absorb sulfuric acid. The exhaust gas used as the agent enters the absorption tower, forming a fluorosilicic acid solution from the bottom of the absorption tower, which is discharged as raw material, and can be directly returned to the raw material recycling in the AHF production process prepared by the fluorosilicic acid method, and the absorption tower The non-condensable gas flowing out from the top of the column is discharged directly as exhaust gas.

Furthermore, the pure HF liquid inlet side end of the HF rectification process described above is installed at the bottom of the upper stage or the top of the lower stage, and the H ₂ O, H ₂ SO ₄ , SO ₂ , SiF ₄ , NH ₃ contained in the raw material gas , CO ₂ , H ₂ SiF ₆ depending on the size of the main impurity fraction content.

Further, the non-condensable gas formed after condensation of the distillate from the bottom of the upper rectification or the top of the lower rectification of the HF rectification process described above is AHF gas with a purity greater than 99.99%, and After condensing to form an AHF liquid, it enters a fluorine exchange resin to further remove Me+ to form a UPSS electronic level AHF liquid, which can optionally be blended with deionized water to form an HF solution. , can meet the needs of various concentrations in the semiconductor industry.

The beneficial effects of the present invention compared to the prior art are as follows.

1) The present invention uses high-concentration HF gas produced in the AHF production process prepared by the traditional fluorite method or fluorosilicic acid method as a raw material, and uses the raw material as EL/UP/UPS to UPSS required by the semiconductor industry. By preparing electronic level AHF gases or gases down to liquids, the problems of phase equilibrium limitations or short adsorbent service life of separation processes such as traditional rectification, distillation, absorption or chemisorption that AHF refining undergoes are overcome. Settled. It filled a void in the art.

2) The present invention relates to the adsorption/condensation/rectification/membrane separation coefficients and physical Taking advantage of the difference in chemical properties, the two-stage mesophilic pressure adsorption process is mainly adopted, and the combination of condensation, membrane separation and HF rectification is used to achieve the consistency and equilibrium of adsorption and desorption in the mesophilic pressure adsorption process. By facilitating the circulation operation of , separation and purification are achieved, and deep dehydration and removal of HF are realized.

3) In the chemical adsorption method, which is a prior art, the present invention adsorbs by a chemical (chelate) reaction that occurs at low temperatures between HF and an adsorbent, whereas the decomposition reaction that occurs at high temperatures is desorption. to overcome the problem that the adsorbent loss rate is large in the process of frequent cycling between adsorption and desorption. At the same time, for crude HF or pure HF obtained by fluorite method or fluorosilicic acid method containing water or sulfuric acid or _SiF4 , the adsorbent in prior art chemisorption also chemically reacts with impurity fractions such as water. occurs, the adsorbent becomes powdered and the effect is significantly lost, and deep dehydration removal cannot be performed efficiently. It is possible to avoid such a phenomenon and extend the service life of the adsorbent.

4) In the present invention, the simple rectification process in the AHF refining process has large fluctuations in the temperature in the middle part of the rectification column, the temperature at the bottom does not meet the requirements, and the HF concentration fluctuation is relatively large. It is possible to avoid the problem that the effect is unfavorable. The present invention first adopts a two-stage PSA, which removes most of the main heavy fraction impurities first, reduces the fluctuation of the HF concentration entering the HF rectification process, and adopts the upper and lower two-stage rectification system. from which the deep dehydration and removal prepared by the AHF product can be realized, and the electronic level AHF product can be obtained at the same time as the HF aqueous solution with a concentration of 40-49%.

5) The present invention obtains the production of electronic level AHF, and at the same time, the material from the medium temperature pressure pressure adsorption and HF rectification process returns to the front end condensation or ammonia water decarburization, etc., and further recovers HF to produce AHF products. yield of more than 90%, and achieve the target of exhaust gas emission through the exhaust gas absorption process.

It is a process drawing of Example 1 of this invention. It is process drawing of Example 2 of this invention.

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail. It should be noted that the specific examples described in this application are used only for the purpose of explaining the invention and are not intended to limit the invention. That is, the described embodiments are some, but not all embodiments of the present invention.
Example 1
As shown in FIG. 1, in the separation and purification method for refining industrial-level high-concentration HF into electronic-level FTrPSA, the source gas is non-aqueous hydrogen fluoride (AHF) prepared by the fluorite method and the fluorosilicic acid method. from industrial-level high-concentration hydrogen fluoride (HF) gas generated in the production process of HF with a concentration of 98% (v / v) has a water content (H ₂ O) of 1%, and other impurities are sulfur dioxide (SO ₂ ), silicon tetrafluoride (SiF ₄ ), ammonia (NH ₃ ), fluorosilicic acid (H ₂ SiF ₆ ), carbon dioxide (CO ₂ ), chloride (calculated with HCl) The total is 0.9 to 1.0%, and the concentration of metal ions (Me+), mainly sodium (Na), magnesium (Mg), calcium (Ca), and arsenic (As) ions, is extremely high. Trace ppm level, fine particles (dss≧1 μm) greater than 100, temperature is 20-30° C., pressure is normal pressure, and the specific implementation steps consist of the following.
(1) The raw material gas undergoes cold heat exchange between 60 and 70°C, and is pressurized to 0.2 to 0.3 MPa by a suction blower, and then enters the medium temperature pressure adsorption step in a two-stage pressure-pressure adsorption (PSA) composition, There are three first-stage PSA (1 ^# PSA) adsorption towers, one is for adsorption, and the other two adsorption towers are for depressurization and evacuation, respectively, for filling the raw material gas and desorbing the final filling. In the process, the raw gas enters from the bottom of the 1 ^# PSA adsorption tower, the operating pressure of 1 ^# PSA is 0.2-0.3 Mpa, the operating temperature is 60-70 ℃, the adsorption tower in the adsorption process The non-adsorbed phase gas flowing out from the top of the column is pure HF gas. Exported as electronic EL level hydrofluoric acid product, the pure HF liquid formed after condensation enters the next process, membrane separation, and the desorption gas flows out from the bottom of the 1 ^# PSA adsorption tower in the desorption process. enters from the bottom of the adsorption tower of the second stage PSA (2 ^# PSA) after pressure increase and cold heat exchange, 2 ^# PSA is composed of three adsorption towers, one adsorption tower is always in the adsorption state, the other The two adsorption towers are respectively in pressure reduction and evacuation, pure HF gas filling pressure and desorption state of final charge, adsorption and desorption cycle operation, the operating pressure of 2 ^# PSA adsorption tower is 0.2 ~ 0.3MPa. The operating temperature is 60 to 70 ° C., and the non-adsorbed phase intermediate gas flowing out from the top of the 2 ^# PSA adsorption tower in the adsorption state is mixed with the raw material gas and returned to 1 ^# PSA, and then adsorbed by 2 ^# PSA. The gas that flows out from the tower is the concentrated gas, which is then subjected to the ammonia water decarburization process, and the effective distillate is recovered by intermediate temperature pressure pressure adsorption.
(2) From the medium temperature pressure pressure adsorption process, the pure HF liquid formed after condensation is boosted to 1.6 MPa, the temperature is 60-70 ℃, enters the first-class inorganic ceramic membrane separation system, and the membrane pore size is 0.6 MPa. 2 to 0.4 micrometers, the film material is zirconia, titanium oxide and aluminum oxide composite film, the content of zirconia and titanium oxide exceeds aluminum oxide, the corrosion-resistant tetrafluoroethylene is used as the anticorrosion sealing material, and the multi-layer The membrane module forming the lane internal pressure type effluents purified pure HF liquid from the permeation side of the membrane, the content of SS particles larger than 1 μm in diameter is less than 25 units/milliliter (Ea/ml), and the following Entering the HF rectification process, the SS concentrate is concentrated on the non-permeable side of the membrane, cooled and sedimented, the SS particles are removed, the liquid is heated and pressurized, and then returned to the membrane separation system. Membrane separation to recover effective fractions.
(3) HF rectification is the purified pure HF liquid from the membrane separation process, and enters the rectification tower of the HF rectification process, and the rectification tower of this process adopts an upper and lower two-stage rectification composition, The purified pure HF liquid enters from the top of the lower rectification, the operating temperature of the upper rectification column is 18-30°C, and the light end impurity gas distilled from the top of the upper rectification column is mainly SO ₂ , It is composed of low-boiling impurity fractions such as _SiF4 , and after returning to the subsequent exhaust gas absorption process, the non-condensable gas formed after condensation from the bottom distillate of the upper rectification is AHF gas, with a purity of 99. Greater than 99%, as a direct electronic UP or UPS level AHF commodity gas, the liquid formed after condensation is used as the reflux of the upper rectification, the operating temperature of the lower rectification is 20-100 ℃, the lower rectification The bottom stream of the impurity fraction containing a small amount of heavy fraction distilled from the bottom of the is condensed to form a non-condensable gas, returned to the medium temperature pressure pressure adsorption step, and the effective fraction is recovered and condensed to form The resulting liquid enters the subsequent ammonia water decarburization process as an absorbent, and the operating pressure of HF rectification is 0.03-0.2 Mpa.
(4) Condensed gas from medium temperature pressure pressure adsorption process, after pressure increase to 0.03-0.2 MPa by suction blower, after condensation of aqueous ammonia, sulfuric acid and rectified distillate from lower stage of HF rectification process Entering the forming liquid, mixing ammonia water decarburization absorption tower as absorbent according to the ratio of 5:3:2, discharging the formed ammonium hydrogen carbonate and ammonium hydrogen fluoride mixed solution from the absorption tower bottom, As a return or premixed reactant in the AHF production process prepared as a direct fluorosilicic acid method, the non-condensable gas flowing out of the top of the ammonia water decarburization absorption tower enters the subsequent exhaust gas absorption process. charcoal.
(5) The light fraction impurity gas distilled from the top of the upper rectification tower in the HF rectification process is mixed with the non-condensable gas from the top of the ammonia water decarburization absorption tower, and the exhaust gas is mixed with sulfuric acid as an absorbent. It enters the absorption tower, forms a fluorosilicic acid solution from the bottom of the absorption tower, is discharged as a raw material, returns to the recycled use of the raw material in the AHF production process prepared by the fluorosilicic acid method, and flows out from the top of the absorption tower. Exhaust gas absorption, exhaust gas is discharged directly as exhaust gas.
Example 2
As shown in FIG. 2, on the basis of Example 1, the raw material gas is the high-concentration HF gas in the AHF production process prepared by the fluorite method, without the impurity fraction of _NH3 or _CO2 , and the ammonia water decarburization process. can be omitted. That is, the condensed gas from the medium temperature pressure pressure adsorption step returns to the condensation step in the AHF production process prepared by the fluorite process to recover more effective fractions.
Example 3
Based on Examples 1 and 2, the adsorbent composition ratio loaded in the 1 ^# PSA adsorption tower in the above medium temperature pressure pressure adsorption process is aluminum:silica gel:molecular sieve=5:3:2, and in the 2 ^# PSA adsorption tower The adsorbent composition ratio to be loaded is 4:2:4.

While the foregoing examples represent specific implementations of the present application, and the description thereof is more specific and detailed, they should be understood as limiting the scope of protection sought by the claims of the present application. must not. note that. Under the premise of the technical idea of the invention of this application, a person with ordinary knowledge in the technical field of this application can make some modifications and improvements, which are all within the scope of protection of this application. belongs to

Claims (6)

(1) The raw material gas undergoes cold heat exchange between 50 and 80° C. and is pressurized to 0.2 to 0.3 MPa, and then enters a medium temperature pressure pressure adsorption process consisting of two-stage pressure pressure adsorption (PSA), Each stage pressure pressure adsorption is composed of at least two or more adsorption towers, at least one adsorption tower is in the adsorption process, and the remaining adsorption towers are reverse depressurization or evacuation, pressurization or final filling and other different stages of desorption. In the process, the feed gas enters from the bottom of the first stage PSA (1 ^# PSA) adsorption tower, the operating pressure of 1 ^# PSA is 0.2-0.3 MPa, the operating temperature is 50-80 ℃, The non-adsorbed phase gas flowing out from the top of the adsorption tower in the adsorption step is pure HF gas, and the non-condensed gas after condensation is precision filtered, and after absorbing deionized water, the concentration obtained is 40 to 49. % HF aqueous solution is exported as a general electronic EL level hydrofluoric acid commodity, and the pure HF formed after condensation enters the next process, membrane separation, into the 1 ^# PSA adsorption tower in the desorption process. The desorbed gas flowing out from the bottom of the tower is pressurized and subjected to cold heat exchange, and then enters the bottom of the adsorption tower of the second stage PSA (2 ^# PSA), and the operating pressure of the 2 ^# PSA adsorption tower is 0.2-0. .3 MPa, the operating temperature is 50-80° C., and the non-adsorbed phase intermediate gas flowing out from the top of the 2 ^# PSA adsorption tower in the adsorption process is mixed with the raw material gas and fed to the 1 ^# PSA adsorption tower. Returning, the desorbed gas flowing out from the bottom of the 2 ^# PSA adsorption tower is a concentrated gas, and enters the subsequent ammonia water decarburization step to recover the effective fraction, a medium temperature pressure pressure adsorption step,
(2) The pure HF liquid condensed and formed from the medium-temperature pressure-pressure adsorption step is pressurized to 1.0-1.6 MPa, the temperature is 50-80° C., and the inorganic Enter the ceramic membrane or stainless steel membrane separation system, the membrane pore size is less than 1 micrometer, the clarified pure HF liquid flows out from the permeated side of the membrane, and the content of SS particles with a diameter greater than 1 micrometer is 25 units. / milliliter (Ea/ml), enter the next step, HF rectification, concentrate the SS particle concentrate on the non-permeated side of the membrane, cool and precipitate, and then remove the SS particles. , a membrane separation step of heating and pressurizing the liquid, returning it to the membrane separation system, and recovering the effective fraction;
(3) The purified pure HF liquid from the membrane separation process enters the rectification column of the HF rectification process, and the rectification column in this process adopts the configuration of upper and lower two-stage rectification, and the purified pure HF liquid is The light end impurity gas that enters from the top of the lower rectification or the bottom of the upper rectification and is removed from the top of the upper rectification column returns to the subsequent exhaust gas absorption step, and enters the bottom of the upper rectification or the top of the lower rectification. The non-condensable gas formed after condensation of the distillate is AHF gas, the purity is greater than 99.99%, directly into the electronic UP or USP level AHF commodity gas, and the liquid formed after condensation is the upper or as a circulation stream of the lower rectification, the non-condensable gas formed after condensation of the bottom fluid of the impurity fraction containing a small amount of heavy fraction distilled from the bottom of the lower rectification is returned to the temperature pressure pressure adsorption step, Furthermore, an HF rectification step in which the effective fraction is recovered and the liquid formed after condensation is used as an absorbent to enter the next step, ammonia water decarburization,
(4) The concentrated gas from the medium-temperature pressure-pressure adsorption step, after being pressurized to normal pressure or a slight overpressure, into the liquid formed after condensation of aqueous ammonia, sulfuric acid and the rectified distillate from the lower stage of the HF rectification step. Ammonium hydrogen carbonate and ammonium hydrogen fluoride mixed solution formed from the bottom of the absorption tower is discharged from the absorption tower bottom, and AHF is directly used as a fluorosilicic acid method. Ammonia water decarburization step to prepare a return or premixed reactant in the production process. The raw material gas described in step (1) contains industrial-level high-concentration hydrogen fluoride (HF) gas produced in the non-aqueous hydrogen fluoride (AHF) production process prepared by the fluorite method or the fluorosilicic acid method. HF at a concentration of 95-99% (v/v) and sulfuric acid (H ₂ SO ₄ ), water (H ₂ O), sulfur dioxide (SO ₂ ), silicon tetrafluoride (SiF ₄ ), ammonia (NH ₃ ), fluorosilicic acid (H ₂ SiF ₆ ), carbon dioxide (CO ₂ ), chloride (calculated with HCl), metal ions (Me+) and fine particles (SS) and other impurity fractions, and Me+ is mainly water-soluble sodium (Na), magnesium (Mg), calcium (Ca), arsenic (As) ions, the diameter of the SS particles is greater than 1 micrometer (μm), the temperature is 20-60 ° C. The separation and purification method for purifying industrial-level high-concentration HF into electronic-level FTrPSA according to claim 1, wherein the pressure is normal pressure or micro-pressure. The separation and purification of industrial-level high-concentration HF to electronic-level FTrPSA according to claim 1, wherein the microfilter membrane or ultrafiltration membrane of the media separation system in step (2) is a membrane module. purification method. The light fraction impurity gas distilled from the top of the upper rectification tower in the HF rectification process is mixed with the non-condensable gas from the top of the ammonia water decarburization absorption tower, and the exhaust gas is absorbed using sulfuric acid as an absorbent. Entering the tower, forming a fluorosilicic acid solution from the bottom of the absorption tower, discharging it as a raw material, can be directly returned to the raw material recycling use in the non-aqueous hydrogen fluoride AHF production process prepared by the fluorosilicic acid method, and the absorption tower The separation and purification for refining industrial-level high-concentration HF to electronic-level FTrPSA according to claim 1, further comprising an exhaust-gas absorption step in which the non-condensable gas flowing out from the top of the column is directly discharged as exhaust gas. Method. The adsorption tower in the medium temperature pressure pressure adsorption step is loaded with activated aluminum oxide, silica gel and molecular ^sieve . (4-6):(2-4):(1-3) and the weight ratio of aluminum oxide:silica gel:molecular sieve in the adsorbent composition loaded in the 2 ^# PSA adsorption tower is (3-5):( 1-3): The separation and purification method for refining industrial-level high-concentration HF to electronic-level FTrPSA according to claim 1, characterized in that (3-5). The non-condensable gas formed after condensation of the distillate from the bottom of the upper rectification or the top of the lower rectification of the HF rectification process described above is AHF gas, with a purity greater than 99.99%, and further condensed. to form an AHF liquid, then enter a fluorine exchange resin to further remove Me+ to form a UPSS electronic level AHF liquid, which can optionally be mixed with deionized water to form an HF solution, and a semiconductor The separation and purification method for purifying industrial-level high-concentration HF into electronic-level FTrPSA according to claim 1, which can meet the various concentration demands of the industry.

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