A method for preparing ultra-high purity hydrochloric acid by heterogeneous flow, and a method for purifying hydrogen chloride

Abstract

The application discloses a method for preparing ultrahigh-purity hydrochloric acid by adopting heterogeneous flow, and a purification method of hydrogen chloride. The method first adopts a complexing agent and a reducing agent to remove impurities from hydrogen chloride. The simultaneous action of the two reagents overcomes the problem of difficult removal of the azeotrope of hydrochloric acid and tin tetrachloride and the influence of free chlorine. An ultrahigh-purity heterogeneous flow medium film layer is artificially manufactured by using non-hydrogen chloride materials, gas-liquid exchange is formed, and hydrogen chloride gas is purified by adopting heterogeneous flow. Ultrahigh-purity hydrochloric acid is obtained by absorbing ultrapure water, the single metal of the ultrahigh-purity hydrochloric acid is less than 10 ppt, the ultrahigh-purity hydrochloric acid reaches the SEMIC12 standard of the International Semiconductor Association, and meets the preparation requirements of chips with a diameter of 12 inches or above. The ultrahigh-purity hydrochloric acid can be used for cleaning and etching of high-integration chips. In addition, ultrahigh-purity hydrogen chloride can be obtained by freezing and compression, the purity of the hydrogen chloride can reach 6.5N, and the hydrogen chloride meets the requirements of special gases for semiconductors. Compared with the prior art, the method has the advantages of simple process flow, high production efficiency, energy saving and environmental protection, and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of purification of super-clean high-purity electronic chemicals, in particular to a method for preparing super-high-purity hydrochloric acid by using heterogeneous flow, a method for purifying hydrogen chloride, and the super-high-purity hydrochloric acid can be applied in the preparation of other super-high-purity reagents, semiconductor integrated circuit manufacturing, electronic material manufacturing, chemical industry, etc. BACKGROUND

[0002] With the rapid development of China's semiconductor and electronic industry, super-high-purity electronic chemicals are the core and key step in the manufacturing process, which are used for cleaning silicon wafers and other electronic components, removing surface impurities and oxide layers, and cleaning and etching chips. In addition, super-high-purity hydrochloric acid can also be used for metal surface treatment to remove surface oxides and other impurities, and electronic-grade hydrochloric acid is mainly used as an acidic cleaning agent for cleaning various metals, organic matter, and particles.

[0003] Currently, super-high-purity hydrochloric acid is mainly prepared by recycling distillation and falling film absorption from industrial-grade hydrochloric acid as raw material. This method cannot effectively remove metal ions and other particulate impurities, especially tin and free chlorine, which are the main difficult-to-remove impurities in super-high-purity hydrochloric acid. Since tin tetrachloride is easily formed with hydrochloric acid to form azeotrope, it is difficult to remove them by conventional distillation process, and the removal effect is poor. In continuous production, the product purity is affected, and the impurities in the discharged residual liquid cause pollution. SUMMARY

[0004] The present application solves one or more problems in the prior art and provides an improved method for preparing super-high-purity hydrochloric acid, which can effectively and efficiently remove impurities in hydrogen chloride, especially tin and free chlorine which are difficult to remove by conventional methods.

[0005] The present application also provides a method for purifying hydrogen chloride.

[0006] To achieve the above-mentioned purpose, one technical solution adopted by the present application is as follows:

[0007] A method for preparing super-high-purity hydrochloric acid by using heterogeneous flow, wherein the mass content of each metal cation in the super-high-purity hydrochloric acid is below 10 ppt, and the mass content of each anion except chloride ion is below 50 ppb. The method uses hydrogen chloride as raw material, the impurities contained in the hydrogen chloride include tin tetrachloride and free chlorine, and the method comprises the following steps:

[0008] Step (1): Pretreatment of hydrogen chloride

[0009] The raw material hydrogen chloride is introduced into an aqueous reaction system for pretreatment to obtain pretreated hydrogen chloride; wherein the aqueous reaction system comprises water, a complexing agent capable of forming chlorostannic acid salt in ionic form from tin tetrachloride, and a reducing agent capable of reducing chlorine in free chlorine into chloride ions;

[0010] Process (2): heterogeneous flow purification of hydrogen chloride

[0011] The pretreated hydrogen chloride is formed into a gas stream to be treated and purified through a heterogeneous flow purification layer to obtain purified hydrogen chloride; wherein in the heterogeneous flow purification layer, a non-hydrogen chloride liquid fluid is used to form a heterogeneous flow, and a heterogeneous flow medium film for gas-liquid exchange is formed between the heterogeneous flow and the gas stream to be treated.

[0012] Process (3): collection of hydrogen chloride

[0013] The purified hydrogen chloride is absorbed by water and / or hydrochloric acid to obtain ultrahigh-purity hydrochloric acid.

[0014] In the present application, it has been found that after tin tetrachloride is converted into chlorostannic acid salt in ionic form, azeotrope is not formed in the system, and thus can be intercepted by the aqueous reaction system.

[0015] In some embodiments of the present application, in process (1), the water is from one or more of the following materials added in combination: pure water, tap water, deionized water, distilled water, and dilute hydrochloric acid with a mass concentration of less than 20%.

[0016] In some embodiments of the present application, in process (1), the complexing agent is one or more of the following in combination: ferric humate, sodium nitrilotriacetic acid, malic acid, phenol, and sodium alginate.

[0017] In some embodiments of the present application, in process (1), the reducing agent is one or more of the following in combination: ferrous sulfate, zinc, iron, aluminum, and alloys of two or three of zinc, iron, and aluminum. Further, in process (1), the reducing agent is one or more of the following in combination: ferrous sulfate, zinc, iron, aluminum, aluminum-iron alloy, aluminum-zinc alloy, iron-zinc alloy, and aluminum-iron-zinc alloy.

[0018] In some embodiments of the present application, in process (1), the mass ratio of the water to the raw material hydrogen chloride is 0.001-20:100. According to some specific aspects of the present application, the mass ratio of the water to the raw material hydrogen chloride in process (1) can be, but is not limited to, 0.001:100, 0.01:100, 0.1:100, 1:100, 2:100, 5:100, 10:100, 12:100, 15:100, 16:100, 17:100, 18:100, 19:100, etc.

[0019] In some embodiments of the present application, in process (1), the mass concentration of the complexing agent in the aqueous reaction system is 0.01-30000 ppm. According to some specific aspects of the present application, in process (1), the mass concentration of the complexing agent in the aqueous reaction system includes but is not limited to 0.01 ppm, 0.1 ppm, 1 ppm, 5 ppm, 10 ppm, 20 ppm, 50 ppm, 100 ppm, 150 ppm, 200 ppm, 300 ppm, 500 ppm, 1000 ppm, 1500 ppm, 3000 ppm, 5000 ppm, 8000 ppm, 10000 ppm, 12000 ppm, 15000 ppm, 16000 ppm, 18000 ppm, 19000 ppm, etc.

[0020] In some embodiments of the present application, in process (1), the mass concentration of the reducing agent in the aqueous reaction system is 0.01-40000 ppm. According to some specific aspects of the present application, in process (1), the mass concentration of the reducing agent in the aqueous reaction system includes but is not limited to 0.1 ppm, 1 ppm, 100 ppm, 50 ppm, 100 ppm, 200 ppm, 500 ppm, 800 ppm, 1000 ppm, 2000 ppm, 3000 ppm, 5000 ppm, 10000 ppm, 12000 ppm, 15000 ppm, 20000 ppm, 25000 ppm, 30000 ppm, 35000 ppm, etc.

[0021] In some embodiments of the present application, in process (1), the pretreatment is carried out at a temperature of -85-108℃ and a pressure of 0.01-1000 kPa.

[0022] Further, in process (1), the pretreatment is carried out at a temperature of 10-108℃ and a pressure of 0.01-1000 kPa.

[0023] According to some specific aspects of the present application, in process (1), the pretreatment is carried out at a pressure of 0.01-10 kPa, 10-50 kPa, 55-100 kPa, 105-120 kPa, 150-200 kPa, 250-300 kPa, 350-400 kPa, 450-500 kPa, 550-700 kPa, 750-800 kPa, or 850-950 kPa.

[0024] In some embodiments of the present application, in step (1), the time of the pretreatment is controlled to be 0.01-1800 minutes. According to some specific aspects of the present application, in step (1), the time of the pretreatment is controlled to be 0.01 minute, 0.1 minute, 1 minute, 10 minutes, 100 minutes, 200 minutes, 500 minutes, 1000 minutes, 1200 minutes, 1400 minutes, 1500 minutes, 1600 minutes, 1800 minutes, etc.

[0025] In some embodiments of the present application, in step (2), the non-hydrogen chloride liquid fluid is one or a combination of several selected from pure water, hydrochloric acid, sulfuric acid, and phosphoric acid.

[0026] In some embodiments of the present application, when the non-hydrogen chloride liquid fluid is hydrochloric acid, the mass percentage concentration of hydrogen chloride in the hydrochloric acid used is 0.001%-99.9%, for example, it can be 1%-99%, or it can be 10%-80%.

[0027] In some embodiments of the present application, when the non-hydrogen chloride liquid fluid is sulfuric acid, the sulfuric acid used is an aqueous solution of sulfuric acid, and the mass percentage concentration is 0.01%-98%, for example, it can be 0.01%-80%, or it can be 1%-70%, or it can be 5%-60%, or it can be 5%-50%, or it can be 5%-40%, or it can be 5%-30%.

[0028] In some embodiments of the present application, when the non-hydrogen chloride liquid fluid is phosphoric acid, the phosphoric acid used is an aqueous solution of phosphoric acid, and the mass percentage concentration is 0.01%-96%, for example, it can be 0.01%-80%, or it can be 1%-70%, or it can be 5%-60%, or it can be 5%-50%, or it can be 5%-40%, or it can be 5%-30%.

[0029] In some preferred embodiments of the present application, the non-hydrogen chloride liquid fluid can be pure water with added sulfuric acid, or pure water with added phosphoric acid, or pure water with added sulfuric acid and phosphoric acid, etc.

[0030] In the present application, in addition to the raw material hydrogen chloride, the other reagents used are preferably of high purity to reduce the introduction of additional impurities.

[0031] In some embodiments of the present application, in step (2), the flow rate of the heterogeneous flow is proportional to the flow rate of the gas flow to be treated.

[0032] In some embodiments of the present application, in step (2), the ratio of the flow rate of the heterogeneous stream to the flow rate of the gas stream to be treated is 0.0001-10:1. According to some specific aspects of the present application, in step (2), the ratio of the flow rate of the heterogeneous stream to the flow rate of the gas stream to be treated includes but is not limited to 0.001:1, 0.01:1, 0.1:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 9.5:1, 10:1, etc.

[0033] In some embodiments of the present application, in step (2), the pre-treated hydrogen chloride forms the gas stream to be treated by controlling the evaporation temperature to be -85-108℃.

[0034] In some embodiments of the present application, in step (2), the thickness of the heterogeneous stream medium film is 0.001-25mm. According to some specific aspects of the present application, in step (2), the thickness of the heterogeneous stream medium film includes but is not limited to 0.001mm, 0.01mm, 0.1mm, 1mm, 2mm, 3mm, 5mm, 8mm, 10mm, 12mm, 15mm, 16mm, 17mm, 18mm, 20mm, 22mm, etc.

[0035] According to the present application, in step (2), during the flow of the heterogeneous stream, the hydrogen chloride in the heterogeneous stream can reach or approach a saturated state and form or approach a supercritical state, and the heterogeneous stream medium film can allow the hydrogen chloride in the supercritical state to pass through and trap impurities or mist.

[0036] In some embodiments of the present application, in step (2), during the gas-liquid exchange, the heterogeneous stream flows from top to bottom, and the gas stream to be treated flows from bottom to top, and the two streams collide with each other. Further, during the flow from top to bottom, the concentration of hydrogen chloride in the heterogeneous stream increases until it approaches or reaches a saturated state, and when in the saturated state, the heterogeneous stream presents a mixed state of gas and liquid, which can be used to absorb gas mist impurities with a size of less than 10 microns.

[0037] In some embodiments of the present application, in step (2), the bottom of the heterogeneous stream purification layer is further provided with a liquid receiving tray, and the gas stream to be treated is introduced into the heterogeneous stream purification layer through the liquid receiving tray. In the process of introduction, the liquid receiving tray reduces the flow rate of the gas stream to be treated, and / or the liquid receiving tray makes the flow direction of the gas stream to be treated intersect with the flow direction of the heterogeneous stream when the gas stream to be treated contacts the heterogeneous stream.

[0038] Further, the liquid receiving tray comprises a liquid receiving pipe with a through hole and used for guiding the gas flow to be treated, a liquid receiving cap arranged on the liquid receiving pipe and having a gap between the upper end surface of the through hole, the liquid receiving cap being capable of preventing fluid from passing through itself, and the orthographic projection of the liquid receiving pipe being located within the orthographic projection of the liquid receiving cap.

[0039] In some embodiments of the present application, the height of the liquid receiving pipe is 3-5 times the height of the liquid surface of the liquid accumulated at the bottom of the heterogeneous flow purification layer.

[0040] In some embodiments of the present application, the liquid receiving tray has a plurality of liquid receiving pipes, and the sum of the radial cross-sectional areas of the through holes of all the liquid receiving pipes accounts for 50%-80% of the radial cross-sectional area of the heterogeneous flow purification layer.

[0041] In the present application, the liquid receiving tray is arranged to help control the gas-liquid exchange to form a liquid film and avoid the formation of mist at a too high rate, without affecting the passage of the hydrogen chloride gas after the removal of impurities by pretreatment into the artificially manufactured heterogeneous flow medium film layer.

[0042] In some embodiments of the present application, the flow state of the gas flow to be treated in the liquid receiving tray is controlled to be a laminar flow state with a Reynolds number less than 2300.

[0043] According to some preferred aspects of the present application, the flow rate of the gas flow to be treated is controlled to be less than or equal to 0.6 m / s. In some embodiments of the present application, the flow rate of the gas flow to be treated is controlled to be 0.1 m / s, 0.2 m / s, 0.3 m / s, 0.35 m / s, 0.4 m / s, 0.45 m / s, 0.5 m / s, etc.

[0044] According to some preferred aspects of the present application, in process (2), the ratio of the heterogeneous flow to the gas flow to be treated is controlled so that the hydrogen chloride content in the heterogeneous flow is 36%-96% when the heterogeneous flow reaches the bottom of the heterogeneous flow purification layer. In some embodiments of the present application, in process (2), the ratio of the heterogeneous flow to the gas flow to be treated is controlled so that the hydrogen chloride content in the heterogeneous flow is 36%-96% when the heterogeneous flow reaches the liquid receiving tray, which can maintain a relatively high exchange rate of hydrogen chloride without complete vaporization.

[0045] According to some preferred aspects of the present application, in step (2), the non-volatile phosphoric acid and / or sulfuric acid is controlled in the heterogeneous flow, and the amount of the phosphoric acid and / or sulfuric acid added accounts for 2%-98% of the heterogeneous flow, for example, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 15%, 18%, 20%, 25%, 30%, 35%, 40%, 45%, etc. This setting can better make the heterogeneous flow still in a stable liquid film fluid state before reaching the bottom of the heterogeneous flow purification layer, for example, before reaching the liquid receiving tray, to ensure the separation and purification effect.

[0046] According to some preferred aspects of the present application, in step (2), the temperature in the heterogeneous flow purification layer is controlled to be -85-51.4 ℃, and the pressure is controlled to be 1-8260 kPa. This setting can better make the heterogeneous flow still in a stable liquid film fluid state before reaching the bottom of the heterogeneous flow purification layer, for example, before reaching the liquid receiving tray, to ensure the separation and purification effect.

[0047] In some embodiments of the present application, the method is a continuous production process, and the feeding speed of the raw material hydrogen chloride is 0.0001-100000 m 3 / h.

[0048] In some embodiments of the present application, the production rate of the ultra-high purity hydrochloric acid is 0.1-2000 L / h.

[0049] In some embodiments of the present application, the mass concentration of the ultra-high purity hydrochloric acid is 20%-38%.

[0050] In some embodiments of the present application, in step (2), the method further comprises: making the to-be-treated gas flow first pass through a demisting layer, then entering the heterogeneous flow purification layer; collecting the mist condensate obtained after the demisting of the demisting layer and the heterogeneous flow obtained after the purification of the heterogeneous flow purification layer, and periodically heating and resolving, so that the resolved hydrogen chloride gas flow sequentially passes through the demisting layer and the heterogeneous flow purification layer to obtain purified hydrogen chloride, and the mother liquor obtained by resolution is periodically cooled and extracted.

[0051] In some embodiments of the present application, the method is carried out by using a production device, and the production device comprises a reaction kettle, a purification tower and an absorption tower which are sequentially communicated, the purification tower comprises a demisting layer and a heterogeneous flow purification layer which are sequentially arranged from bottom to top, the demisting layer is communicated with the reaction kettle, and the heterogeneous flow purification layer is communicated with the absorption tower.

[0052] Another technical solution provided by the present application is a purification method of hydrogen chloride, wherein the impurities contained in the hydrogen chloride include tin tetrachloride and free chlorine, and the purification method comprises:

[0053] Step (1): pretreatment of hydrogen chloride

[0054] The raw material hydrogen chloride is introduced into an aqueous reaction system for pretreatment to obtain pretreated hydrogen chloride; wherein the aqueous reaction system comprises water, a complexing agent capable of forming chlorostannic acid salt in ionic form with tin tetrachloride, and a reducing agent capable of reducing chlorine in free chlorine into chloride ions;

[0055] Step (2): heterogeneous flow purification of hydrogen chloride

[0056] The pretreated hydrogen chloride is formed into a to-be-treated gas stream, which is purified by passing through a heterogeneous flow purification layer to obtain purified hydrogen chloride with a purity of 6.5N or above; wherein in the heterogeneous flow purification layer, a non-hydrogen chloride liquid flow is used to form a heterogeneous flow, and a heterogeneous flow medium film for gas-liquid exchange is formed between the heterogeneous flow and the to-be-treated gas stream.

[0057] In some embodiments of the present application, the purification method is carried out by using a production device comprising a reaction kettle, a purification tower, a drying mechanism, and a high-purity hydrogen chloride storage tank connected in sequence, wherein the purification tower comprises a mist removal layer and a heterogeneous flow purification layer arranged in sequence from bottom to top, the mist removal layer is connected with the reaction kettle, and the heterogeneous flow purification layer is connected with the drying mechanism.

[0058] Alternatively, the purification method is carried out by using a production device comprising a reaction kettle, a purification tower, a heat exchanger, a gas-liquid separator, a compressor, and a high-purity hydrogen chloride storage tank connected in sequence, wherein the purification tower comprises a mist removal layer and a heterogeneous flow purification layer arranged in sequence from bottom to top, the mist removal layer is connected with the reaction kettle, and the heterogeneous flow purification layer is connected with the heat exchanger.

[0059] In the present application, the mist removal layer can be a conventional product, which will not be described in detail here.

[0060] Thanks to the above technical solutions, the present application has the following advantages compared with the prior art:

[0061] The present application is based on the problems of the existing technology of preparing ultra-high purity hydrochloric acid, such as the non-ideal purity, the difficulty of removing impurities, etc. The present application provides an improved method for preparing ultra-high purity hydrochloric acid. The method first removes the difficult-to-remove impurities tin and free chlorine in hydrogen chloride as much as possible by pretreatment. Specifically, the method uses the simultaneous action of two reagents to overcome the problem of the azeotropic removal of hydrochloric acid and tin tetrachloride and the influence of free chlorine. Then, the method forms a gas-liquid exchange interface between the heterogeneous flow formed by a non-hydrogen chloride liquid and the hydrogen chloride gas stream obtained after pretreatment. This method simulates the reflux part of rectification and artificially creates a heterogeneous flow medium membrane to form a gas-liquid purification exchange membrane, thereby achieving the purification of hydrogen chloride gas. This heterogeneous flow purification method does not require ultra-high temperature and ultra-low temperature conditions, has low requirements for equipment, realizes the ultra-high purity purification of hydrogen chloride, and further uses pure water and other absorption to obtain ultra-high purity hydrochloric acid.

[0062] In the present application, in the ultra-high purity hydrochloric acid prepared by the heterogeneous flow process of the present application, the content of each single anion is less than 50 ppb, and the content of each single metal ion is less than 10 ppt, except for chloride ions. Compared with existing methods, the method of the present application has simple process and equipment, high production efficiency, low energy consumption, good product quality stability, and product quality that meets or exceeds the requirements of SEMI C12 standard. The product can be used in the fields of other ultra-high purity reagent preparation, semiconductor integrated circuit manufacturing, chip etching, pickling steel, etc. In addition, ultra-high purity hydrogen chloride can be obtained by freezing and compression. The purity of the hydrogen chloride can reach 6.5N, meeting the requirements of semiconductor special gas. BRIEF DESCRIPTION OF DRAWINGS

[0063] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0064] Figure 1 The structure schematic diagram of the production device used in the embodiments of the present application;

[0065] Figure 2 The structure schematic diagram of the liquid receiving tray in the embodiments of the present application;

[0066] In the drawing marks: 1, raw material tank; 2, reaction kettle; 3, purification tower; 31, tower kettle; 32, demisting layer; 33, heterogeneous flow purification layer; 34, heterogeneous flow supply mechanism; 341, heterogeneous flow storage tank; 342, heterogeneous flow pump; 35, liquid receiving tray; 351, liquid receiving pipe; 3511, through hole; 352, liquid receiving cap; 353, support column; 36, liquid distributor; 4, absorption tower; 5, first heat exchanger; 6, absorption tank; 61, circulating pump; 7, finished product tank; 8, second heat exchanger; 9, compressor; 10, high-purity hydrogen chloride storage tank; 101, collection tank; 102, industrial-grade material buffer tank. DETAILED DESCRIPTION

[0067] The concept of the present application mainly includes: learning from the technology and skills of the reflux part in the rectification technology, the present application artificially manufactures an ultra-high-purity heterogeneous flow medium film layer by using non-hydrogen chloride substances, and forms a gas-liquid exchange layer. In the process, hydrogen chloride molecules and non-hydrogen chloride liquid flowing together collide with each other, reflux is formed through gas-liquid exchange, the concentration of hydrogen chloride in the heterogeneous flow increases and approaches or reaches a saturated state and forms or approaches a supercritical state, when in this semi-gas semi-liquid state, the heterogeneous flow forms a similar liquid film in a mixed state of gas and liquid, this film only allows hydrogen chloride molecules in a supercritical state to pass through, and impurities and mist are blocked, thereby achieving impurity removal; at the same time, before using the heterogeneous flow to remove impurities, the present application uses a water-containing reaction system to treat raw hydrogen chloride, so that stannic chloride is converted into ionic chlorostannate, and then an azeotrope is not formed in the system, and can be intercepted by the water-containing reaction system, and the chlorine in free chlorine can be reduced to chloride ions, thereby laying a foundation for further impurity removal of the heterogeneous flow, and realizing the preparation of ultra-high-purity hydrochloric acid with the mass content of each metal cation below 10 ppt, and the mass content of each anion below 50 ppb except chloride ions.

[0068] Compared with the traditional rectification process, the present application reduces the requirements for the corrosion resistance and heat transfer performance of the equipment, and also reduces the energy consumption in the purification process; the present application significantly reduces the requirements for the production conditions of enterprises.

[0069] Based on this, the present application provides a method for preparing ultra-high-purity hydrochloric acid by using a heterogeneous flow and a hydrogen chloride purification method, the hydrogen chloride contains impurities including stannic chloride and free chlorine, the method for preparing ultra-high-purity hydrochloric acid by using a heterogeneous flow includes the steps of the hydrogen chloride purification method, and after obtaining the purified hydrogen chloride (the purity of hydrogen chloride can reach 6.5N (purity above 99.9999%)), ultra-high-purity hydrochloric acid can be prepared by using water (preferably water with few impurities, such as pure water) and / or hydrochloric acid absorption, and pure water can be supplemented as needed to ensure the absorption effect.

[0070] Further, the hydrogen chloride purification method includes:

[0071] Process (1): Pretreatment of hydrogen chloride

[0072] The raw material hydrogen chloride is introduced into an aqueous reaction system for pretreatment to obtain pretreated hydrogen chloride; wherein the aqueous reaction system comprises water, a complexing agent capable of forming stannic chloride in ionic form, and a reducing agent capable of reducing chlorine in free chlorine into chloride ions;

[0073] Process (2): Heterogeneous flow purification of hydrogen chloride

[0074] The pretreated hydrogen chloride is formed into a gas stream to be treated and purified by a heterogeneous flow purification layer to obtain purified hydrogen chloride; wherein in the heterogeneous flow purification layer, a non-hydrogen chloride liquid flow is used to form a heterogeneous flow, and a heterogeneous flow medium film of gas-liquid exchange is formed between the heterogeneous flow and the gas stream to be treated.

[0075] The following will be described in combination with Figures 1 to 2 The above-mentioned method for preparing ultra-high purity hydrochloric acid by using a heterogeneous flow and the purification method of hydrogen chloride will be further described, Figure 1 The production device shown can be continuously produced or intermittently produced, and the following will be described by taking continuous production as an example;

[0076] The production device comprises a raw material tank 1, a reaction kettle, a purification tower, an absorption tower, a first heat exchanger, an absorption tank, a finished product tank, a circulating pump, a heterogeneous flow supply mechanism, a second heat exchanger, a gas-liquid separator, a compressor, a high-purity hydrogen chloride storage tank, a collection tank, and an industrial-grade material buffer tank.

[0077] The raw material tank 1, the reaction kettle 2, the purification tower 3, the absorption tower 4, the first heat exchanger 5, and the absorption tank 6 are sequentially communicated to form a route for preparing ultra-high purity hydrochloric acid.

[0078] The raw material tank 1, the reaction kettle 2, the purification tower 3, the second heat exchanger 8, the gas-liquid separator (not shown), the compressor 9, and the high-purity hydrogen chloride storage tank 10 are sequentially communicated to form a route for purifying hydrogen chloride, i.e., a route for preparing ultra-high purity hydrogen chloride.

[0079] The purification tower 3 comprises, from bottom to top, a tower kettle 31, a mist removal layer 32, a liquid receiving disc 35, a heterogeneous flow purification layer 33, and a liquid distributor 36; the mist removal layer 32 is communicated with the reaction kettle 2 through the tower kettle 31; the heterogeneous flow purification layer 33 is communicated with the absorption tower 4 or the second heat exchanger 8; and the heterogeneous flow supply mechanism 34 is communicated with the liquid distributor 36.

[0080] Among them:

[0081] Raw material tank 1 can be used to buffer raw material hydrogen chloride or as a transfer tank for raw material hydrogen chloride. It is connected to reactor 2 for introducing raw material hydrogen chloride into reactor 2. Reactor 2 also has one or more inlets for introducing an aqueous reaction system, allowing water, complexing agent, and reducing agent to be introduced into reactor 2 for pretreatment of the raw material hydrogen chloride. The mass ratio of water to raw material hydrogen chloride is 0.001-20:100. The complexing agent includes, but is not limited to, one or more combinations selected from ferric humate, sodium triacetate, malic acid, phenol, and sodium alginate, which can form tin tetrachloride into the ionic form of chlorostannate. Chlorostannate does not form an azeotrope in the system and can therefore be retained by the aqueous reaction system. The mass concentration of the complexing agent is 0.01-30000 ppm. The reducing agent includes, but is not limited to, ferrous sulfate, zinc, iron, aluminum, and one or more combinations of two or three alloys of zinc, iron, and aluminum, which can reduce chlorine in free chlorine to usable chloride ions. The mass concentration of the reducing agent is 0.01-40000 ppm. In this reaction vessel 2, the processing time (0.01-1800 min), processing temperature (-85~108℃), and processing pressure (0.01-10 kPa) can be controlled as needed to achieve the desired impurity removal effect.

[0082] The purified system is continuously fed into the bottom 31 of the purification tower 3, where temperature-controlled evaporation can be carried out (evaporation temperature is -85 to 108°C, for example, 10 to 108°C), so that the pretreated hydrogen chloride in the system forms the gas stream to be treated; of course, if the amount of aqueous reaction system in the reactor 2 is insufficient, additional aqueous reaction system can be added. The source of the additional aqueous reaction system can be a new aqueous reaction system, or an aqueous reaction system recovered from the bottom 31, or both.

[0083] The resulting gas flow to be treated first passes through a demisting layer 32 (a conventional design can be used, which will not be described in detail here). After demisting, it is introduced into the heterogeneous flow purification layer 33 through a liquid receiving tray 35. Specifically, in the heterogeneous flow purification layer 33, the demisted gas flow to be treated first passes through the liquid receiving tray 35 to control the flow rate and change the contact mode with the heterogeneous flow. See [link to relevant documentation]. Figure 2 As shown, the receiving tray 35 includes a receiving pipe 351 with a through hole 3511 for introducing the gas flow to be treated, and a receiving cap 352 disposed on the receiving pipe 351 with a gap between it and the upper end face of the through hole 3511. The receiving cap 352 can prevent fluid from passing through itself. The orthographic projection of the receiving pipe 351 is located within the orthographic projection of the receiving cap 352. This ensures that the gas flow to be treated will not collide violently with the downward-flowing heterogeneous flow after entering the heterogeneous flow purification layer 33. Figure 2As shown, the to-be-processed gas stream enters first through the through hole 3511, and then escapes from the gap, while the liquid receiving cap 352 directly blocks the direct and violent collision between the heterogeneous flow and the to-be-processed gas stream, reduces the generation of mist, and is conducive to maintaining the state of the heterogeneous flow medium film,

[0084] Further, in the process of top-down flow, the concentration of hydrogen chloride in the heterogeneous flow increases until it approaches or reaches a saturated state, and the hydrogen chloride in the heterogeneous flow can form or approach a supercritical state, and the heterogeneous flow medium film can allow the hydrogen chloride in or near the supercritical state to pass through and trap impurities or mist, so that the hydrogen chloride continuously enters and exits, realizing impurity removal; at the same time, the height of the liquid receiving pipe 351 is 3-5 times the liquid level height of the liquid accumulated at the bottom of the heterogeneous flow purification layer (i.e. the setting position of the liquid receiving disc 35), and the liquid receiving disc 35 can have multiple side-by-side arrangements, the sum of the radial cross-sectional areas of all through holes 3511 of the liquid receiving pipe 351 accounts for 50%-80% of the radial cross-sectional area of the heterogeneous flow purification layer 33, and the setting of the liquid receiving disc 35 can help control the gas-liquid exchange to form a liquid film without affecting the passage of the pre-processed and impurity-removed hydrogen chloride gas into the artificially manufactured heterogeneous flow medium film layer, thereby avoiding the formation of mist at too high a rate;

[0085] In addition, in order to better facilitate or ensure that the heterogeneous flow can form a stable liquid state in the heterogeneous flow purification layer, and ensure the separation and purification effect, the ratio of the heterogeneous flow to the to-be-processed gas stream can be controlled so that when the heterogeneous flow reaches the liquid receiving disc 35, the hydrogen chloride content in the heterogeneous flow is 36%-96%, which can maintain a high exchange speed of hydrogen chloride while not completely vaporizing, and / or the heterogeneous flow contains non-volatile phosphoric acid and / or sulfuric acid, and the addition amount of phosphoric acid and / or sulfuric acid accounts for 2%-98% of the heterogeneous flow, and / or the temperature in the heterogeneous flow purification layer is -85-51.4℃, and the pressure is 1-8260kPa.

[0086] Further, in some specific cases, the non-hydrogen chloride liquid fluid is one or a combination of several selected from pure water, hydrochloric acid, sulfuric acid, and phosphoric acid, for example, it can be pure water added with sulfuric acid, it can be pure water added with phosphoric acid, it can be pure water added with sulfuric acid and phosphoric acid, etc., the ratio of the flow rate of the heterogeneous flow to the flow rate of the to-be-processed gas stream is 0.0001-10:1, and the thickness of the heterogeneous flow medium film is controlled to be 0.001-25mm, and the flow rate of the to-be-processed gas stream is controlled to be less than or equal to 0.6m / s.

[0087] Further, the heterogeneous flow is supplied to the heterogeneous flow purification layer 33 by the heterogeneous flow supply mechanism 34, preferably, a liquid distributor 36 is used to uniformly distribute the heterogeneous flow, the heterogeneous flow supply mechanism 34 comprises a heterogeneous flow storage tank 341 and a heterogeneous flow pump 342, the heterogeneous flow pump 342 is used to pump the heterogeneous flow stored in the heterogeneous flow storage tank 341 to the liquid distributor 36, and the heterogeneous flow is uniformly distributed to the heterogeneous flow purification layer 33 through the liquid distributor 36;

[0088] After being treated by the purification tower 3, ultra-high purity hydrogen chloride is obtained, in which the mass content of each metal cation is less than 10 ppt, and the mass content of each anion is less than 50 ppb except for chloride ions; if it is necessary to prepare ultra-high purity hydrochloric acid, it can be introduced into the absorption tower 4 to be absorbed by pure water and / or hydrochloric acid, and then ultra-high purity hydrochloric acid is obtained. In actual operation, as shown in Figure 1 pure water is filled in the absorption tank 6, and then pumped into the upper part of the absorption tower 4 by the circulating pump 61, and the hydrogen chloride introduced is absorbed by spraying to form an aqueous hydrogen chloride solution (i.e. hydrochloric acid), which is then cooled by the first heat exchanger 5 and introduced into the absorption tank 6, and the cycle is repeated, and the newly obtained hydrochloric acid with low concentration is used to absorb the ultra-high purity hydrogen chloride, and when the concentration is increased to the desired concentration after a certain period of circulation, it can be discharged to the finished product tank 7 for storage or external delivery, and pure water can be supplemented into the absorption tank 6 as needed to ensure the absorption effect; if it is directly collected in the form of ultra-high purity hydrogen chloride, the hydrogen chloride treated by the purification tower 3 can be introduced into the second heat exchanger 8 for cooling, and then separated from the possible water and other liquids by a gas-liquid separator (not shown), and then compressed by the compressor 9 and stored in the high-purity hydrogen chloride storage tank 10, which can be multiple in parallel.

[0089] In addition, the mist condensate obtained after demisting and the heterogeneous flow obtained after purification by the heterogeneous flow purification layer can be introduced into the collection tank 101, and periodically heated and resolved, and the hydrogen chloride gas stream resolved is sequentially introduced into the demisting layer 32, the liquid receiving tray 35 and the heterogeneous flow purification layer 33 to obtain high-purity hydrogen chloride, and the mother liquor obtained by resolution is periodically cooled and extracted, and can be stored in the industrial-grade material buffer tank 102 for sale as industrial products.

[0090] The above scheme will be further described in combination with specific examples; it should be understood that these examples are used to illustrate the basic principles, main features and advantages of the present application, and the present application is not limited in scope by the following examples; the implementation conditions used in the examples can be further adjusted according to specific requirements, and the implementation conditions not mentioned are usually the conditions in conventional experiments.

[0091] In the following description, all raw materials can be obtained from commercial sources or prepared by conventional methods in the art.

[0092] The content of hydrochloric acid or hydrogen chloride of the present application is analyzed by sodium hydroxide titration method, the content of metal ions is detected by inductively coupled plasma mass spectrometer (ICP-MS, Thermo X-7 series), and anions are detected by liquid phase ion chromatograph (equipment Dionex Aquion IC). High-purity hydrogen chloride is detected by gas chromatograph (equipment GOW-MAC, GM1900PDHID-C42, USA).

[0093] The raw material hydrogen chloride is industrial premium grade GB 7746-2011, and the content of hydrogen chloride is greater than 99.99%.

[0094] Examples 1-6

[0095] The present examples provide a method for preparing ultra-high-purity hydrochloric acid by heterogeneous flow, which adopts the production device shown in the figure, Figure 1 the liquid receiving disc structure shown in the figure, and the above production process, wherein: Figure 2

[0096] The specific operation process is shown in Table 1, wherein the height of the liquid receiving pipe is n times (3-5 times) the liquid level height of the liquid accumulated at the bottom of the heterogeneous flow purification layer, and the sum of the radial cross-sectional areas of the through holes of all the liquid receiving pipes accounts for X% (50%-80%) of the radial cross-sectional area of the heterogeneous flow purification layer.

[0097] Table 1

[0098]

[0099] Results test

[0100] The hydrochloric acid products of the above examples 1-6 are detected as follows, and the product detection results are shown in Table 2.

[0101] Table 2 Detection results of examples 1-6

[0102]

[0103]

[0104] Note: The negative values in the table are the actual detection results of the ICP-MS instrument, and the negative values only represent that the impurity content of the sample is lower than the detection limit of the equipment.

[0105] The hydrogen chloride products prepared in the above examples 3-6 are detected as follows (the hydrogen chloride product prepared in example 3 corresponds to example 7, the hydrogen chloride product prepared in example 4 corresponds to example 8, the hydrogen chloride product prepared in example 5 corresponds to example 9, and the hydrogen chloride product prepared in example 6 corresponds to example 10), and the product detection results are shown in Table 3.

[0106] Table 3​

[0107] Item Units Example 7 Example 8 Example 9 Example 10 [H2] ppm vol / vol 0.07 0.06 0.05 0.05 [N2] ppm vol / vol 0.14 0.18 0.15 0.16 [O2 + Ar] ppm vol / vol 0.06 0.07 0.05 0.09 CO ppm vol / vol 0.08 0.06 0.09 0.05 CO2 ppm vol / vol 0.12 0.16 0.14 0.15 THC(CH4) ppm vol / vol 0.1 0.08 0.05 0.09 H2O ppm vol / vol 0.1 0.05 0.06 0.06 Fe ppm wht / vol 0.05 0.01 0.07 0.026 Cr ppm wht / vol 0.01 0.007 0.005 0.009 Ni ppm wht / vol 0.01 0.006 0.009 0.008 Cu ppm wht / vol 0.01 0.005 0.007 0.008 Co ppm wht / vol 0.01 0.007 0.006 0.006

[0108] The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and principle of the present application should be covered within the protection scope of the present application.

[0109] The endpoints of the ranges and any values claimed herein are not limited to the precise values recited as the exact dimensions are not, in some cases, critical to the present application. Any stated ranges are intended to include endpoints that are either inclusive or exclusive. The scope of the application is not intended to be limited by the recitation of the precise range or value, but rather, any range or value that approximates a stated range or value is intended to be within the scope of the present application.

Claims

1. A method for producing ultrapure hydrochloric acid by heterogeneous flow, in which the mass content of each metal cation is 10 ppt or less, and the mass content of each anion other than chloride ions is 50 ppb or less, using hydrogen chloride as a raw material, the raw material hydrogen chloride containing impurities including stannic chloride and free chlorine, characterized in that, The method comprises: Process (1): Pretreatment of hydrogen chloride The raw hydrogen chloride is introduced into an aqueous reaction system for pretreatment to obtain pretreated hydrogen chloride; wherein the aqueous reaction system comprises water, a complexing agent capable of forming ionized stannic chloride from stannic chloride, and a reducing agent capable of reducing chlorine in free chlorine into chloride ions; Process (2): Heterogeneous flow purification of hydrogen chloride The pretreated hydrogen chloride is formed into a gas stream to be treated and is purified by passing through a heterogeneous flow purification layer to obtain purified hydrogen chloride; wherein in the heterogeneous flow purification layer, a non-hydrogen chloride liquid fluid is used to form a heterogeneous flow, and a heterogeneous flow medium membrane for gas-liquid exchange is formed between the heterogeneous flow and the gas stream to be treated; Process (3): Collection of hydrogen chloride The purified hydrogen chloride is absorbed by water and / or hydrochloric acid to obtain ultrahigh-purity hydrochloric acid.

2. The method for preparing ultra-high purity hydrochloric acid by using heterogeneous flow according to claim 1, characterized in that, In process (1), the water is from one or a combination of the following materials: pure water, tap water, deionized water, distilled water, and dilute hydrochloric acid with a mass concentration of less than 20%; and / or, In process (1), the complexing agent is one or a combination of one or more of the following: ferric humate, sodium nitrilotriacetic acid, malic acid, phenol, and sodium alginate; and / or, In process (1), the reducing agent is one or a combination of one or more of the following: ferrous sulfate, zinc, iron, aluminum, and alloys of two or three of zinc, iron, and aluminum; and / or, In process (1), the mass ratio of water to raw hydrogen chloride is 0.001-20:100; and / or, In process (1), in the aqueous reaction system, the mass concentration of the complexing agent is 0.01-30000 ppm; and / or, In process (1), in the aqueous reaction system, the mass concentration of the reducing agent is 0.01-40000 ppm; and / or, In process (1), the pretreatment is carried out at a temperature of -85-108℃ and a pressure of 0.01-1000 kPa; and / or, In process (1), the pretreatment time is controlled to be 0.01-1800 min.

3. The method of claim 1, wherein the method of preparing ultra-high purity hydrochloric acid by heterogeneous flow is characterized by, In process (2), the non-hydrogen chloride liquid fluid is one or a combination of one or more of the following: pure water, hydrochloric acid, sulfuric acid, and phosphoric acid; and / or, in process (2), the flow rate of the heterogeneous flow is proportional to the flow rate of the gas stream to be treated; and / or, in process (2), the ratio of the flow rate of the heterogeneous flow to the flow rate of the gas stream to be treated is 0.0001-10:1; and / or, in process (2), the pretreated hydrogen chloride is formed into a gas stream to be treated by controlling the evaporation temperature, and the evaporation temperature is -85-108℃; and / or, in process (2), the thickness of the heterogeneous flow medium membrane is 0.001-25 mm.

4. The method of claim 1, wherein the method is characterized by, In process (2), during the flow of the heterogeneous flow, the hydrogen chloride in the heterogeneous flow can reach or approach a saturated state and form or approach a supercritical state, and the heterogeneous flow medium membrane can allow the hydrogen chloride in the supercritical state to pass through and trap impurities or mist.

5. The method of claim 1, wherein the method is characterized by, In the process (2), in the process of the gas-liquid exchange, the heterogeneous flow flows from top to bottom and the gas flow to be treated flows from bottom to top, and the two flows collide with each other; wherein, in the process of flowing from top to bottom, the concentration of hydrogen chloride in the heterogeneous flow increases until it approaches or reaches a saturated state, and when in the saturated state, the heterogeneous flow is in a mixed state of gas and liquid, which can be used to absorb aerosol impurities with a size of less than 10 microns.

6. The method of claim 1, wherein the method is a method of preparing ultra-high purity hydrochloric acid using heterogeneous flow, characterized in that, In the process (2), the bottom of the heterogeneous flow purification layer is further provided with a liquid receiving tray, and the gas flow to be treated is introduced into the heterogeneous flow purification layer through the liquid receiving tray. In the process of introduction, the liquid receiving tray reduces the flow rate of the gas flow to be treated, and / or the liquid receiving tray makes the flow direction of the gas flow to be treated intersect with the flow direction of the heterogeneous flow when the gas flow to be treated contacts the heterogeneous flow.

7. The method for preparing ultra-high purity hydrochloric acid by using heterogeneous flow according to claim 6, characterized in that, The liquid receiving tray includes a liquid receiving pipe having a through hole and used for introducing the gas flow to be treated, and a liquid receiving cap provided on the liquid receiving pipe and having a gap between the through hole and the upper end face of the through hole, the liquid receiving cap being capable of preventing fluid from passing through itself, and the orthographic projection of the liquid receiving pipe being located within the orthographic projection of the liquid receiving cap.

8. The method for preparing ultra-high purity hydrochloric acid by using heterogeneous flow according to claim 7, characterized in that, The height of the liquid receiving pipe is 3-5 times the liquid level height of the liquid accumulated at the bottom of the heterogeneous flow purification layer; and / or the liquid receiving tray has a plurality of liquid receiving pipes, and the sum of the radial cross-sectional areas of the through holes of all the liquid receiving pipes accounts for 50%-80% of the radial cross-sectional area of the heterogeneous flow purification layer.

9. The method of claim 6, wherein the method is a method of producing ultra-high purity hydrochloric acid by heterogeneous flow, characterized by, The flow state of the gas flow to be treated in the liquid receiving tray is controlled to be a laminar flow state with a Reynolds number less than 2300.

10. The method for preparing ultra-high purity hydrochloric acid by using heterogeneous flow according to any one of claims 1-9, characterized in that, The flow rate of the gas flow to be treated is controlled to be less than or equal to 0.6 m / s.

11. The method of claim 1-9 for the production of ultra-pure hydrochloric acid by heterogeneous flow, characterized in that, In the process (2), the ratio of the heterogeneous flow to the gas flow to be treated is controlled so that the hydrogen chloride content in the heterogeneous flow is 36%-96% when the heterogeneous flow reaches the bottom of the heterogeneous flow purification layer; and / or, In the process (2), the heterogeneous flow contains phosphoric acid and / or sulfuric acid, and the addition amount of the phosphoric acid and / or sulfuric acid accounts for 2%-98% of the heterogeneous flow; and / or, In the process (2), the temperature in the heterogeneous flow purification layer is controlled to be -85~51.4 ℃, and the pressure is controlled to be 1-8260 kPa; and / or, The process is a continuous production process, the feed rate of the raw material hydrogen chloride is 0.0001-100000 m 3 / h; and / or, The production rate of the ultrahigh-purity hydrochloric acid is 0.1-2000 L / h; and / or, The mass concentration of the ultrahigh-purity hydrochloric acid is 20%-38%; and / or, In the process (2), the method further includes making the gas flow to be treated pass through a demisting layer first, then entering the heterogeneous flow purification layer, collecting the mist condensate obtained after the demisting layer is demisted and the heterogeneous flow obtained after the heterogeneous flow purification layer is purified, and periodically heating and resolving, so that the resolved hydrogen chloride gas flow passes through the demisting layer and the heterogeneous flow purification layer in turn to obtain purified hydrogen chloride, and the mother liquor obtained by resolution is periodically cooled and extracted; and / or, The method is carried out by using a production device, which comprises a reaction kettle, a purification tower and an absorption tower connected in sequence, wherein the purification tower comprises a demisting layer and a heterogeneous flow purification layer arranged in sequence from bottom to top, the demisting layer is communicated with the reaction kettle, and the heterogeneous flow purification layer is communicated with the absorption tower.

12. A method for purifying hydrogen chloride, which uses hydrogen chloride as a raw material, the raw material hydrogen chloride containing impurities including stannic chloride and free chlorine, characterized by, The purification method comprises: Process (1): pretreatment of hydrogen chloride The raw hydrogen chloride is introduced into an aqueous reaction system for pretreatment to obtain pretreated hydrogen chloride; wherein the aqueous reaction system comprises water, a complexing agent capable of forming a chlorostannic acid salt in an ionic form with tin tetrachloride, and a reducing agent capable of reducing chlorine in free chlorine into chloride ions; Process (2): heterogeneous flow purification of hydrogen chloride The pretreated hydrogen chloride is formed into a gas flow to be treated and is purified by passing through a heterogeneous flow purification layer to obtain purified hydrogen chloride with a purity of 6.5N or more; wherein in the heterogeneous flow purification layer, a non-hydrogen chloride liquid flow is used to form a heterogeneous flow, and a heterogeneous flow medium film for gas-liquid exchange is formed between the heterogeneous flow and the gas flow to be treated.

13. The purification method of hydrogen chloride according to claim 12, characterized by, The purification method is carried out by using a production device, which comprises a reaction kettle, a purification tower, a drying mechanism and a high-purity hydrogen chloride storage tank connected in sequence, wherein the purification tower comprises a demisting layer and a heterogeneous flow purification layer arranged in sequence from bottom to top, the demisting layer is communicated with the reaction kettle, and the heterogeneous flow purification layer is communicated with the drying mechanism; Alternatively, the purification method is carried out by using a production device, which comprises a reaction kettle, a purification tower, a heat exchanger, a gas-liquid separator, a compressor and a high-purity hydrogen chloride storage tank connected in sequence, wherein the purification tower comprises a demisting layer and a heterogeneous flow purification layer arranged in sequence from bottom to top, the demisting layer is communicated with the reaction kettle, and the heterogeneous flow purification layer is communicated with the heat exchanger.

Images