Electronic grade glycine purification unit based on solvent-thermal phase boundary fractionation

Abstract

This invention provides an electronic-grade glycine purification unit based on solvothermal phase boundary sieving, belonging to the field of chemical production technology. It includes a raw material dissolution and degassing tank 1, a slit-type directional purification chamber 2, a solvent receiving chamber 3, a phase boundary anchoring plate 11, a first temperature control jacket 4, a second temperature control jacket 5, a condenser 6, a residual liquid discharge channel 7, a crystal collection channel 8, and a controller 9. By forming a stable meniscus phase boundary within the penetrating microcapillaries, cross-boundary vaporization migration of water and in-situ retention of non-volatile impurities are achieved. Continuous directional crystallization of glycine is achieved through flow-through concentration within the slit channel and preferential growth on the surface of the directional nucleation plate 10. Simultaneous control of impurity and water balance is achieved through online residual liquid discharge and closed-loop condensate recovery. This unit is suitable for the continuous purification and preparation of electronic-grade glycine, achieving high purity, high particle size consistency, and low particulate contamination. The device adopts a closed structure, suitable for large-scale continuous production of electronic chemicals.

Description

Technical Field

[0001] This invention relates to the field of chemical production technology, specifically to an electronic-grade glycine purification unit based on solvothermal phase boundary sieving. Background Technology

[0002] Glycine, as a basic amino acid and complexing component, has stable application requirements in semiconductor wet electronics chemicals, electroplating additive mother liquors, surface treatment auxiliaries, and high-purity functional chemicals. Electronic-grade applications place comprehensive demands on glycine regarding its main content, metal ions, inorganic anions, particle cleanliness, residual mother liquor adhesion, and batch consistency. Among these, impurities such as sodium, potassium, calcium, iron, copper, nickel, chloride ions, and sulfate ions directly affect the stability of downstream solution preparation, filtration life, and the consistency of electrochemical processes.

[0003] Existing glycine purification routes mainly include vacuum evaporation combined with cooling recrystallization, washing with alcohol or alcohol-water systems, electrodialysis desalination, ion exchange, and multiple mother liquor recycling crystallization. These routes can achieve increased content of main components and removal of some inorganic impurities in food-grade, feed-grade, and general industrial-grade products. However, the evaporation interface, supersaturation establishment zone, random nucleation zone, and mother liquor enrichment zone are usually located in the same liquid phase space, resulting in problems such as uncontrolled local supersaturation, high proportion of free fine crystals, significant crystal inclusions, difficulty in controlling particulate impurities, and high levels of residual trace metal ions.

[0004] For electronic-grade target products, the liquid surface disturbance, bubbling splashes, local hot spots, and impurity re-adsorption in traditional open evaporation crystallization systems amplify the aforementioned defects. While electrodialysis and ion exchange systems can handle some ionic impurities, they cannot simultaneously address crystal particle size uniformity, mother liquor entrainment, and particle control within the same unit. Therefore, it is necessary to construct a continuous purification system that partitions the solvent migration location, supersaturation establishment location, crystal growth location, and impurity discharge location to simultaneously complete solvent removal, directional crystallization, and impurity-rich mother liquor discharge within a single device. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an electronic-grade glycine purification unit based on solvothermal phase boundary sieving, which solves the problems of existing technologies.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an electronic-grade glycine purification unit based on solvothermal phase boundary sieving, comprising a raw material dissolution and degassing tank, a slit-type directional purification chamber, a solvent receiving chamber, a phase boundary anchoring plate, a first temperature control jacket, a second temperature control jacket, a condenser 6, a residual liquid discharge channel, a crystal collection channel, and a controller; the phase boundary anchoring plate is disposed between the slit-type directional purification chamber and the solvent receiving chamber, and the phase boundary anchoring plate is provided with an array of through microcapillaries, each through microcapillary extending along the direction from the slit-type directional purification chamber to the solvent receiving chamber; the outlet of the raw material dissolution and degassing tank is connected to the inlet of the slit-type directional purification chamber, the residual liquid discharge channel is connected to the residual liquid outlet of the slit-type directional purification chamber, the crystal collection channel is connected to the crystal outlet of the slit-type directional purification chamber, and the condenser 6 is connected to the solvent receiving chamber; the first temperature control jacket is disposed between the raw material dissolution and degassing tank and the solvent receiving chamber; the first temperature control jacket is disposed between the raw material dissolution and degassing tank and the solvent receiving chamber; the second temperature control jacket is connected to the solvent receiving chamber; the third temperature control jacket is disposed between the raw material dissolution and degassing tank and the solvent receiving chamber; the fourth temperature control jacket is disposed between the raw material dissolution and degassing tank and the solvent receiving chamber; the fifth temperature control jacket is disposed between the raw material dissolution and degassing tank and the solvent receiving chamber; the sixth temperature control jacket is disposed between the raw material dissolution and degassing tank and the solvent receiving chamber; the seventh temperature control jacket is disposed between the raw material dissolution and degassing tank and the solvent receiving chamber; the fifth temperature control jacket is disposed between the raw material dissolution and degassing tank and the solvent receiving chamber; the sixth temperature control jacket is disposed between the raw material dissolution and degas Outside the slit-type directional purification chamber, the second temperature control jacket is disposed outside the solvent receiving chamber; inside the slit-type directional purification chamber, a directional nucleation plate 10 is disposed, the directional nucleation plate 10 and the phase boundary anchoring plate are arranged opposite to each other and jointly define the slit flow channel; the controller is connected to the first temperature control jacket, the second temperature control jacket, the condenser recovery unit 6 and the raw material dissolution and degassing tank respectively, and is used to control the glycine aqueous solution in the slit-type directional purification chamber to be in a heated state and the solvent receiving chamber to be in a cooled state, and to form a stable solvent thermal meniscus phase boundary in each penetrating microcapillary, so that water molecules vaporize through the solvent thermal meniscus phase boundary and enter the solvent receiving chamber and are condensed and recovered by the condenser recovery unit 6, glycine molecules form a controlled supersaturated region in the slit flow channel and crystallize and grow on the surface of the directional nucleation plate 10, and metal ion impurities, inorganic salt impurities and particulate impurities are retained in the slit-type directional purification chamber and discharged through the residual liquid discharge channel.

[0007] Preferably, the pore diameter of the through-microcapillary is 5-60 μm, the pore length is 80-600 μm, the ratio of pore length to pore diameter is 4:1-30:1, the pore surface density is 1000-30000 pores / cm2, and the porosity is 8%-28%; the contact angle of the pore wall on the side of the through-microcapillary near the slit-type directional purification chamber is 20°-70°, and the contact angle of the pore wall on the side near the solvent receiving chamber is 95°-130°.

[0008] Preferably, the slit channels have a spacing of 0.5-6.0 mm, a length of 100-1500 mm, and a width of 20-400 mm; a glycine seed layer is fixedly disposed on the surface of the directional nucleation plate 10, the glycine seed layer has a thickness of 20-500 μm, and the seed layer coverage is 70%-100%; the feed inlet of the slit-type directional purification chamber is located at the lower end, the residual liquid outlet is located at the upper end, and the crystal outlet is located on the bottom side wall.

[0009] Preferably, the first temperature control jacket controls the temperature of the glycine aqueous solution in the slit-type directional purification chamber to be 45-85°C, the second temperature control jacket controls the temperature of the solvent receiving chamber to be 5-25°C, the pressure of the solvent receiving chamber is 5-40 kPa, the pressure of the slit-type directional purification chamber is 20-120 kPa, and the pressure difference between the slit-type directional purification chamber and the solvent receiving chamber is 2-25 kPa.

[0010] Preferably, the raw material dissolving and degassing tank is connected to a vacuum degassing component and a circulating pump. The vacuum degassing component controls the dissolved gas content in the raw material solution to be 0.1-2.0 mg / L. A primary filter and a secondary filter are sequentially installed on the discharge pipeline of the raw material dissolving and degassing tank. The filtration pore size of the primary filter is 1.0-5.0 μm, and the filtration pore size of the secondary filter is 0.05-0.45 μm.

[0011] Preferably, the residual liquid discharge channel is equipped with a conductivity detector, an online metal ion detector, and a discharge valve; the controller controls the opening of the discharge valve according to the detection signals of the conductivity detector and the online metal ion detector, so that the discharge volume of the residual liquid discharge channel accounts for 1%-20% of the inlet volume of the slit-type directional purification chamber; the condensate outlet of the condenser recovery unit 6 is connected to the raw material dissolution and degassing tank.

[0012] Preferably, the components in contact with the material in the raw material dissolving and degassing tank, slit-type directional purification chamber, solvent receiving chamber, phase boundary anchoring plate, primary filter, secondary filter, residual liquid discharge channel, crystal collection channel, and condenser recovery unit 6 are made of PFA, PTFE, quartz, alumina ceramic, and electropolished 316L stainless steel; the phase boundary anchoring plate is made of alumina ceramic, silicon nitride ceramic, or sintered quartz.

[0013] Preferably, the method for purifying electronic-grade glycine based on solvothermal phase-interface sieving includes the following steps: S1. Add crude glycine and deionized water to the raw material dissolving and degassing tank to prepare a raw material solution with a glycine mass fraction of 8%-30%, and then heat the raw material solution to 45-85℃ and perform vacuum degassing. S2. The raw material solution obtained in S1 is filtered sequentially through a primary filter and a secondary filter, and then continuously introduced into the slit-type directional purification chamber from the feed inlet at the lower end of the slit-type directional purification chamber. S3. Control the first temperature control jacket, the second temperature control jacket, and the condenser 6 to make the temperature of the raw material solution in the slit-type directional purification chamber 45-85℃, the temperature of the solvent receiving chamber 5-25℃, and the pressure of the solvent receiving chamber 5-40kPa. A stable solvent thermal meniscus phase interface is formed in the microcapillaries, so that water molecules vaporize and migrate to the solvent receiving chamber through the solvent thermal meniscus phase interface and are condensed and recovered. S4. During the process of S3, the flow velocity in the slit channel is controlled to be 0.01-0.20 m / s, so that glycine crystallizes in a direction on the surface of the directional nucleation plate 10, and metal ion impurities, inorganic salt impurities and particulate impurities are enriched in the uncrystallized mother liquor. S5. The residual liquid enriched with impurities is continuously discharged from the upper end of the slit-type directional purification chamber, and glycine crystal slurry is continuously discharged from the crystal outlet. The glycine crystal slurry is then subjected to solid-liquid separation, washing, and drying to obtain electronic-grade glycine product.

[0014] Preferably, the glycine seed layer on the surface of the oriented nucleation plate 10 in S4 has a thickness of 20-500 μm; in S5, the glycine crystals after solid-liquid separation are washed with deionized water at a temperature of 0-10℃ and a conductivity of 0.02-1.0 μS / cm, and the amount of washing solution is 5%-30% of the mass of the wet crystals. After washing, the glycine crystals are dried at 40-80℃ and an absolute pressure of 5-50 kPa for 2-20 hours.

[0015] Preferably, the residual liquid discharged in S5 is returned to the raw material dissolving and degassing tank and reconstituted with newly added crude glycine and deionized water to prepare a new raw material solution; the condensate recovered in S3 is returned to the raw material dissolving and degassing tank; the method maintains the pH of the raw material solution at 5.70-6.30 under continuous operation, maintains the residual liquid discharge at 1%-20% of the influent volume of the slit-type directional purification chamber, and maintains the solid content of the crystal slurry at 5%-35%. This invention provides an electronic-grade glycine purification unit based on solvothermal phase-interface sieving. It has the following beneficial effects: 1. This invention establishes a stable solvent thermal meniscus phase boundary through the through-hole microcapillaries on the phase boundary anchoring plate, allowing water to vaporize and migrate across the boundary within the pores, while metal ions, inorganic salts, and particulate impurities remain on the original liquid side, forming a structural condition that separates the desolventization path from the non-volatile impurity path, and maintaining the cleanliness of the condensate during continuous operation.

[0016] 2. This invention defines the slit flow channel by using a directional nucleation plate and a phase boundary anchoring plate together, and pre-places a glycine seed layer on the surface of the directional nucleation plate, so that the supersaturation formed by concentration along the flow path is preferentially consumed by the growth on the plate surface, which significantly reduces the random nucleation of the bulk phase and the formation of fine crystals. The resulting crystals have a more concentrated particle size distribution, lower liquid adsorption, and higher washing efficiency.

[0017] 3. This invention maintains stable impurity balance, water balance and crystal formation rate during long-term operation through online discharge of residual liquid, closed-loop recovery of condensate, temperature and pressure differential linkage control and modular scale-up structure. It not only meets the requirements of electronic-grade glycine for low metal content, low salt content and low particle size, but also has engineering application value of continuous operation, scalability and low open exposure. Attached Figure Description

[0018] Figure 1 This is an overall structural diagram of the present invention; Figure 2 This is a schematic diagram of the layout of the present invention; Figure 3 This is a process flow diagram of the present invention; Figure 4 This is a system architecture diagram of the present invention.

[0019] The components include: 1. Raw material dissolution and degassing tank; 2. Slit-type directional purification chamber; 3. Solvent receiving chamber; 4. First temperature control jacket; 5. Second temperature control jacket; 6. Condenser and recovery unit; 7. Residual liquid discharge channel; 8. Crystal collection channel; 9. Controller; 10. Directional nucleation plate; 11. Phase boundary anchoring plate. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific Implementation Example 1: like Figures 1 to 4As shown, the electronic-grade glycine purification unit based on solvothermal phase boundary sieving includes a raw material dissolution and degassing tank 1, a slit-type directional purification chamber 2, a solvent receiving chamber 3, a phase boundary anchoring plate 11, a first temperature control jacket 4, a second temperature control jacket 5, a condenser 6, a residual liquid discharge channel 7, a crystal collection channel 8, and a controller 9. The phase boundary anchoring plate 11 is located between the slit-type directional purification chamber 2 and the solvent receiving chamber 3. The phase boundary anchoring plate 11 is provided with an array of through microcapillaries, each extending along the direction from the slit-type directional purification chamber 2 to the solvent receiving chamber 3. The outlet of the raw material dissolution and degassing tank 1 is connected to the inlet of the slit-type directional purification chamber 2, the residual liquid discharge channel 7 is connected to the residual liquid outlet of the slit-type directional purification chamber 2, the crystal collection channel 8 is connected to the crystal outlet of the slit-type directional purification chamber 2, and the condenser 6 is connected to the solvent receiving chamber 3. The first temperature control jacket 4 is located between the slit-type directional purification chamber 2 and the solvent receiving chamber 3. Outside the purification chamber 2, the second temperature control jacket 5 is located outside the solvent receiving chamber 3. A directional nucleation plate 10 is installed inside the slit-type directional purification chamber 2. The directional nucleation plate 10 and the phase boundary anchoring plate 11 are arranged opposite to each other and jointly define the slit flow channel. The controller 9 is connected to the first temperature control jacket 4, the second temperature control jacket 5, the condenser 6, and the raw material dissolution and degassing tank 1. It is used to control the glycine aqueous solution in the slit-type directional purification chamber 2 to be in a heated state and the solvent receiving chamber 3 to be in a cooled state. It also makes stable solvent thermal meniscus phase boundaries form in each penetrating microcapillary pore. Water molecules vaporize through the solvent thermal meniscus phase boundaries and enter the solvent receiving chamber 3 and are condensed and recovered by the condenser 6. Glycine molecules form a controlled supersaturated region in the slit flow channel and crystallize and grow on the surface of the directional nucleation plate 10. Metal ion impurities, inorganic salt impurities, and particulate impurities are retained in the slit-type directional purification chamber 2 and discharged through the residual liquid discharge channel 7. The raw material dissolving and degassing tank 1, the slit-type directional purification chamber 2, the solvent receiving chamber 3, and the condenser recovery unit 6 are connected by a fully enclosed rigid pipeline to form a closed operating system. The slit-type directional purification chamber 2 adopts a vertical arrangement structure. The directional nucleation plate 10 is arranged on one side near the crystal collection channel 8, and the phase boundary anchoring plate 11 is arranged on one side near the solvent receiving chamber 3. The liquid flow direction inside the slit channel is continuously advancing from bottom to top. After entering the slit channel, the material simultaneously undergoes a continuous process of controlled desolventization, concentration along the flow path, surface directional growth, and upward discharge of the impurity-rich mother liquor along the flow direction.The controller 9 is simultaneously connected to the feed flow meter, the inlet temperature sensor of the slit-type directional purification chamber 2, the outlet temperature sensor of the slit-type directional purification chamber 2, the pressure sensor of the solvent receiving chamber 3, the pressure sensor of the slit-type directional purification chamber 2, the slurry density meter of the crystal collection channel 8, and the condensate flow meter. The controller 9 uses the temperature difference, pressure difference, and condensate collection rate between the slit-type directional purification chamber 2 and the solvent receiving chamber 3 as the main control variables, and the change rate of crystal slurry solid content and residual liquid conductivity as the auxiliary control variables. It adjusts the heating power of the first temperature control jacket 4, the cooling power of the second temperature control jacket 5, the condensation load of the condenser recovery unit 6, and the feed replenishment of the raw material dissolution and degassing tank 1 in real time to keep the position of the meniscus penetrating the microcapillaries stable inside the channel and not enter the side opening of the solvent receiving chamber 3. This structure fixes the solvent migration interface within the microcapillaries, confines the glycine supersaturation zone within the slit channel, limits the crystal growth zone to the surface of the oriented nucleation plate 10, and confines the impurity enrichment zone within the mainstream of the uncrystallized mother liquor. This spatially separates the solvent migration path, the target component crystallization path, and the impurity discharge path, maintaining a stable mass transfer order under continuous operation. Since non-volatile impurities do not cross the solvent thermal meniscus phase boundary, glycine crystals grow epitaxially on the plate surface, significantly reducing the number of free nuclei in the bulk liquid. Crystal entrainment of mother liquor and fine crystal inclusions are simultaneously suppressed. The most critical metal ions, inorganic salts, and particulate impurities in the preparation of electronic-grade glycine are guided through the residual liquid discharge channel 7 by structural mechanism, achieving integrated coupling between the device configuration and the purification mechanism.

[0022] The pore size of the through-microcapillaries is 5-60 μm, the pore length is 80-600 μm, the ratio of pore length to pore size is 4:1-30:1, the pore surface density is 1000-30000 pores / cm2, and the porosity is 8%-28%. The contact angle of the pore wall near the slit-type directional purification chamber 2 is 20°-70°, and the contact angle of the pore wall near the solvent receiving chamber 3 is 95°-130°. The phase boundary anchoring plate 11 uses a high-density, crack-free ceramic plate or sintered quartz plate as the substrate. The through-microcapillary array is formed by femtosecond laser, ultrashort pulse laser or high-precision mechanical micro-drilling. After the pores are formed, the pore walls are polished, cleaned, ultrasonically desorbed and partitioned surface modified to form a hydrophilic surface on the feed side pore wall and a hydrophobic surface on the cooled side pore wall. The surface modification treatment is carried out in segments along the thickness direction of the plate. A low contact angle surface layer is formed in the range of 0.1-0.4 times the plate thickness on the side near the slit-type directional purification chamber 2, and a high contact angle surface layer is formed in the range of 0.1-0.5 times the plate thickness on the side near the solvent receiving chamber 3. The intermediate transition zone maintains the intrinsic micro-roughness of the substrate, thereby forming a wetting gradient from hydrophilic to hydrophobic throughout the microcapillaries. After the interaction of this wetting gradient and the pore aspect ratio, a stable liquid film is formed at the feed side orifice, a pressure meniscus is formed in the middle section of the channel, and the liquid phase is kept in a state of non-escape at the cooling side orifice. The combination of pore size (5-60 μm) and pore length (80-600 μm) keeps the vapor migration resistance and liquid penetration resistance of a single pore within the same engineering window. The combination of a pore surface density of 1000-30000 pores / cm² and an open porosity of 8%-28% ensures that the total phase interface area per unit area is sufficient to support continuous solvent removal flux, while retaining the mechanical strength and thermal deformation resistance required for the anchoring plate. This microcapillary array is not a typical filter pore structure; stable meniscus phase interfaces are maintained within the pores over a long period. The liquid phase does not perforate the pores, only undergoing solvent vaporization and migration. The phase interface fixation at the microscale directly determines the continuous concentration and directional crystallization process at the macroscale. Therefore, the geometric dimensions of the microcapillaries and the bilateral wettability parameters together constitute the core functional basis of this purification unit.

[0023] The slit channels have a spacing of 0.5-6.0 mm, a length of 100-1500 mm, and a width of 20-400 mm. A glycine seed layer with a thickness of 20-500 μm and a coverage of 70%-100% is fixedly disposed on the surface of the directional nucleation plate 10. The feed inlet of the slit-type directional purification chamber 2 is located at the lower end, the residual liquid outlet is located at the upper end, and the crystal outlet is located on the bottom sidewall. The directional nucleation plate 10 adopts a planar plate structure, and its surface roughness is controlled within the range of Ra0.1-1.0 μm. Before the nucleation plate is assembled, it is pre-wetted with a high-purity glycine saturated solution, and then a continuous seed layer is formed on the plate surface by controlling the cooling rate and surface residence time. After the seed layer is formed, a secondary stabilization treatment is performed to form a stable adhesion interface between it and the substrate of the directional nucleation plate 10, preventing it from being peeled off by the mainstream liquid in the initial stage of startup. When the slit channel spacing is 0.5-6.0 mm, the fluid remains in a laminar flow state within the channel, limiting the lateral diffusion distance. A concentration increase zone forms near the phase boundary anchoring plate 11 due to continuous solvent removal, while a directional growth zone forms near the directional nucleation plate 10 due to the continuous consumption and supersaturation of the seed layer. Thus, a stable concentration gradient is established along the thickness direction of the entire slit channel, and a continuous growth propulsion zone is established along the length direction. With the feed inlet located at the bottom, the raw material liquid enters from the bottom of the slit channel and flows upwards. The liquid residence time is controlled by both the channel length and linear velocity. Impurities in the mother liquor gradually accumulate during the upward flow and are eventually discharged from the upper residual liquid outlet. With the crystal outlet located on the bottom sidewall, crystals thickened to a set size detach from the plate surface and enter the crystal collection channel 8 under the combined action of their own weight, liquid shear force, and the local contraction flow field near the outlet, preventing crystals from staying too long in the upward mainstream region and causing secondary surface adsorption. The slit channel, in conjunction with the directional nucleation plate 10, forms a surface growth unit that advances steadily along the flow path. This allows the glycine precipitation process to occur preferentially on the controlled surface rather than inside the bulk phase, directly improving the controllability of crystal size and the efficiency of subsequent washing.

[0024] The first temperature control jacket 4 controls the temperature of the glycine aqueous solution in the slit-type directional purification chamber 2 to be 45-85℃, and the second temperature control jacket 5 controls the temperature of the solvent receiving chamber 3 to be 5-25℃. The pressure in the solvent receiving chamber 3 is 5-40 kPa, the pressure in the slit-type directional purification chamber 2 is 20-120 kPa, and the pressure difference between the slit-type directional purification chamber 2 and the solvent receiving chamber 3 is 2-25 kPa. The first temperature control jacket 4 adopts a zoned circulating heating method, with at least three temperature control loops along the height direction of the slit-type directional purification chamber 2: a lower heating zone, a middle temperature stabilization zone, and an upper fine-tuning zone. The second temperature control jacket 5 adopts a combination of overall cooling and local cold-end enhancement to make the internal temperature field of the solvent receiving chamber 3 uniform and avoid local condensate backflow impacting the cold side orifice of the anchor plate. When the pressure in the slit-type directional purification chamber 2 is 20-120 kPa, the pressure in the solvent receiving chamber 3 is 5-40 kPa, and the pressure difference between the two is 2-25 kPa, the meniscus phase interface within the penetrating microcapillaries is in a stable tensile state. The direction of water vapor migration across the interface always points from the slit-type directional purification chamber 2 to the solvent receiving chamber 3, and the liquid phase remains on one side of the slit-type directional purification chamber 2 without overall perforation. This combination of temperature and pressure with the pore structure creates a ternary operating condition of high vapor partial pressure on the heated side, low vapor partial pressure on the cooled side, and stable liquid phase position within the pores. Therefore, the concentration rate within the slit channel has a definite correspondence with the temperature difference, pressure difference, and total phase interface area. When the system starts up, the target temperature and target pressure of the solvent receiving chamber 3 are established first, and then the slit-type directional purification chamber 2 is started to heat up and feed, so that when the first batch of raw material liquid enters, a controlled meniscus phase interface is immediately formed in the pore. When the system stops, the feed is stopped first and the cold end is maintained, and then the hot end temperature is gradually reduced, so that the meniscus in the pore shrinks back smoothly and eventually disappears. No thermal shock salting out occurs in the pore during the entire start-up and shutdown process, which is conducive to maintaining the long-term unobstructedness and reusability stability of the microcapillary array.

[0025] The raw material dissolution and degassing tank 1 is connected to a vacuum degassing component and a circulation pump. The vacuum degassing component controls the dissolved gas content in the raw material solution to be between 0.1 and 2.0 mg / L. A primary filter and a secondary filter are sequentially installed on the discharge pipeline of the raw material dissolution and degassing tank 1. The pore size of the primary filter is 1.0-5.0 μm, and the pore size of the secondary filter is 0.05-0.45 μm. The vacuum degassing component consists of a vacuum buffer tank, a condenser protector, a vacuum pump, and a gas-liquid separator at the top of the tank. The circulation pump draws liquid from the bottom of the raw material dissolution and degassing tank 1 and returns it to the upper part of the tank through pipelines, forming continuous circulation within the tank and shortening the degassing equilibrium time. After the raw material liquid is completely dissolved in the tank, it enters the vacuum degassing stage. The vacuum degassing component continuously removes dissolved oxygen, dissolved nitrogen, and microbubble nuclei. The dissolved gas control range of 0.1-2.0 mg / L significantly reduces local flow field turbulence and orifice dry spot formation caused by microbubble adhesion in the subsequent slit-type directional purification chamber 2. The primary filter removes mechanical debris, incompletely dissolved particles, and particles detached from upstream pipelines. The secondary filter removes submicron particles and colloidal impurities. The feed solution after two-stage filtration exhibits low particle size, low bubble density, and low heteronucleation density. The feed dissolution and degassing tank 1 is also equipped with a level sensor, pH sensor, conductivity sensor, and temperature sensor. The controller 9 replenishes deionized water or condensate recovery liquid based on liquid level changes, adjusts the residual liquid reflux ratio based on conductivity changes, and regulates the thermal balance of the feed solution before it enters the slit-type directional purification chamber 2 based on temperature changes, thereby ensuring that the feed solution entering the main purification chamber remains continuous and stable in composition and state. This pretreatment section forms a strict connection with the subsequent slit-type directional purification chamber 2. The front end removes bubble nuclei and heteronucleated particles, while the rear end maintains the stability of phase boundaries and seed layers. The entire system possesses the low-disturbance operating foundation required for electronic-grade purification.

[0026] The residual liquid discharge channel 7 is equipped with a conductivity detector, an online metal ion detector, and a drain valve. The controller 9 controls the opening of the drain valve based on the detection signals from the conductivity detector and the online metal ion detector, ensuring that the discharge volume of the residual liquid discharge channel 7 accounts for 1%-20% of the inlet volume of the slit-type directional purification chamber 2. The condensate outlet of the condenser recovery unit 6 is connected to the raw material dissolution and degassing tank 1. The conductivity detector is located on the side of the residual liquid discharge channel 7 near the slit-type directional purification chamber 2 to reflect the accumulation level of inorganic salt impurities in the uncrystallized mother liquor in real time. The online metal ion detector is located downstream of the conductivity detector to continuously monitor the concentration of one or more target ions among sodium, potassium, calcium, iron, copper, nickel, and zinc. Controller 9 employs a linkage control mode. When the residual liquid conductivity reaches the set upper limit and the metal ion concentration is in the rising stage, the drain valve increases its opening proportionally. When the residual liquid conductivity is in the middle of the set window and the metal ion concentration is stable, the drain valve maintains the baseline opening. When the residual liquid conductivity decreases and the metal ion concentration is near the set lower limit, the drain valve decreases its opening and the total liquid volume of the system is kept stable by replenishing the raw material liquid. When the residual liquid discharge accounts for 1%-20% of the influent volume, the system simultaneously achieves a dynamic balance between impurity discharge and glycine yield. After the condensate outlet is connected to the raw material dissolution and degassing tank 1, the condensate is reintroduced into the front-end liquid distribution section as high-purity recovered water. The condensate temperature is adjusted by the heat exchanger to match the operating conditions of the raw material dissolution and degassing tank 1 before being returned to prevent excessive temperature difference from affecting the stability of the front-end concentration. The residual liquid control and condensate recovery form a dual closed-loop balance mechanism of the system. One end discharges the mother liquor enriched with impurities, and the other end recovers high-purity condensate, thereby ensuring that impurities do not accumulate disorderly in the system during continuous production and that moisture is not lost in an open manner. The device can maintain a stable material balance and impurity balance for a long time.

[0027] The components in contact with the material in the raw material dissolving and degassing tank 1, the slit-type directional purification chamber 2, the solvent receiving chamber 3, the phase boundary anchoring plate 11, the primary filter, the secondary filter, the residual liquid discharge channel 7, the crystal collection channel 8, and the condenser recovery unit 6 are made of PFA, PTFE, quartz, alumina ceramic, and electropolished 316L stainless steel; the phase boundary anchoring plate 11 is made of alumina ceramic, silicon nitride ceramic, or sintered quartz. All metal surfaces in direct contact with the material are controlled to have a surface roughness Ra of less than 0.2 μm after electropolishing. All PFA and PTFE liners are integrally molded or hot-melt coated to avoid particle shedding points and cleaning dead zones at the joints. Quartz components are used for the observation window, the condenser recovery path, and local high-purity liquid guide sections; alumina ceramic and silicon nitride ceramic components are used for the phase boundary anchoring plate 11 and high-stability support components. Before final assembly, all components in contact with materials undergo acid washing, ultrapure water rinsing, clean drying, and sealed storage. After assembly, a system-wide high-purity water circulation cleaning and cleanliness verification are performed to ensure the system achieves low metal precipitation, low ion release, and low particle shedding before initial feeding. The material configuration and clean assembly process together ensure that the purification unit itself does not introduce new metal ions, inorganic salts, or particulate contamination into the glycine system, thus forming an integrated constraint relationship between the device structure and material cleanliness. The requirements for equipment materials in electronic-grade glycine purification not only involve corrosion resistance but also ion precipitation control and particulate control during long-term operation. This technical solution sets clear boundaries simultaneously at the levels of component materials, surface condition, and assembly process.

[0028] The method for purifying electronic-grade glycine based on solvothermal phase interface sieving includes the following steps: S1, adding crude glycine and deionized water to the raw material dissolution and degassing tank 1 to prepare a raw material solution with a glycine mass fraction of 8%-30%, and heating the raw material solution to 45-85℃ before vacuum degassing; S2, filtering the raw material solution obtained in S1 sequentially through a primary filter and a secondary filter, and then continuously introducing it into the slit-type directional purification chamber 2 through the feed inlet at the lower end of the slit-type directional purification chamber 2; S3, controlling the first temperature control jacket 4, the second temperature control jacket 5, and the condenser recovery unit 6 to maintain the temperature of the raw material solution in the slit-type directional purification chamber 2 at 45-85℃ and the temperature of the solvent receiving chamber 3 at 5-25℃. At ℃, the pressure in solvent receiving chamber 3 is 5-40 kPa, forming a stable solvent hot meniscus phase interface through the microcapillaries, allowing water molecules to vaporize and migrate to solvent receiving chamber 3 and be condensed and recovered; S4, during S3, the flow rate in the slit channel is controlled at 0.01-0.20 m / s, causing glycine to crystallize directionally on the surface of the directional nucleation plate 10, enriching metal ion impurities, inorganic salt impurities, and particulate impurities in the uncrystallized mother liquor; S5, the residual liquid enriched with impurities is continuously discharged from the upper end of the slit-type directional purification chamber 2, and glycine crystal slurry is continuously discharged from the crystal outlet. After solid-liquid separation, washing, and drying, the glycine crystal slurry yields electronic-grade glycine product. In S1, the raw material solution is first coarsely dissolved at 30-50℃, then heated to 45-85℃ for complete dissolution and thermal equilibrium treatment, followed by vacuum degassing. Before S2, the second temperature control jacket 5 and the condenser recovery unit 6 are activated to establish a low-pressure environment, and then the first temperature control jacket 4 and the slit-type directional purification chamber 2 are activated for feeding, ensuring that the microcapillaries have the necessary temperature and pressure conditions to form a meniscus phase interface when the raw material solution enters. During S3, the condensation rate of the condenser recovery unit 6 is the same as the feed flow rate. Step matching ensures that the cross-boundary desolventizing flux is maintained at a level that allows the middle section of the slit channel to first reach surface supersaturation. In step S4, when the flow velocity in the slit channel is 0.01-0.20 m / s, the liquid residence time between the plates meets the requirements for simultaneous enrichment along the flow path and surface growth. The seed layer on the directional nucleation plate 10 continuously absorbs supersaturated glycine molecules and thickens along the lattice direction. In step S5, the residual liquid and crystal slurry are continuously discharged from different flow paths, realizing online separation of the product phase and the impurity phase. This method forms a continuous process chain of "front-end liquid preparation and degassing—middle-section phase boundary desolventizing—plate surface directional crystallization—end-end residual liquid removal and crystal slurry collection" during continuous operation. There are no open transfer or intermediate exposure links between the steps, ensuring both process continuity and environmental cleanliness.

[0029] In S4, the glycine seed layer thickness on the surface of the directional nucleation plate 10 is 20-500 μm. In S5, the glycine crystals after solid-liquid separation are washed with deionized water at a temperature of 0-10℃ and a conductivity of 0.02-1.0 μS / cm. The washing solution accounts for 5%-30% of the wet crystal mass. After washing, the glycine crystals are dried at 40-80℃ and an absolute pressure of 5-50 kPa for 2-20 hours. When the seed layer thickness is 20-500 μm, the plate surface has continuous nucleation activity without initial peeling due to excessive seed layer thickness. The newly formed crystal layers during crystal growth continue to develop along the original seed orientation, and the uniformity of plate growth remains stable. Solid-liquid separation is carried out using a closed centrifuge, a closed vacuum filter, or a low-disturbance pusher separator. All contact surfaces during the separation process are made of high-purity inert material. The washing step uses deionized water at 0-10℃ with a conductivity of 0.02-1.0 μS / cm, which reduces the residual concentration of the mother liquor on the crystal surface and prevents product redissolution caused by high-temperature washing solution. When the washing solution volume is 5%-30% of the wet crystal mass, the residual liquid on the crystal surface can be effectively replaced, while the product dissolution loss is kept within a controlled range. The drying step uses vacuum drying at 40-80℃ and an absolute pressure of 5-50 kPa to remove residual moisture in the crystal gaps and on the surface under a low heat load, avoiding particle agglomeration and surface melting caused by high temperature. After the above separation, washing and drying, the obtained glycine crystals have low surface liquid content, low residual ion content and high particle size uniformity. The electronic-grade purification target is further solidified into the final product through a mild post-processing method.

[0030] The residual liquid discharged in S5 is returned to the raw material dissolution and degassing tank 1 and remixed with newly added crude glycine and deionized water to prepare a new raw material solution; the condensate recovered in S3 is returned to the raw material dissolution and degassing tank 1; the method maintains the pH of the raw material solution at 5.70-6.30 under continuous operation, maintains the residual liquid discharge at 1%-20% of the inlet volume of the slit-type directional purification chamber 2, and maintains the solid content of the crystal slurry at 5%-35%. Before the residual liquid is returned, its flow rate, ion load, and temperature are calibrated by an online flow meter, conductivity detector, and temperature controller, and then it is remixed with newly added crude glycine and deionized water in the raw material dissolution and degassing tank 1 according to the set ratio; before the condensate is returned, its conductivity and total organic carbon are tested, and the condensate quality is confirmed to be within the reuse window before entering the raw material dissolution and degassing tank 1. During continuous operation, the pH of the raw material solution is maintained between 5.70 and 6.30 to ensure that glycine is within a stable liquid phase window suitable for directional crystallization and low side reactions. The residual liquid discharge rate accounts for 1%-20% of the influent flow rate to ensure that the impurity discharge rate matches the system impurity inflow rate. The solid content of the crystal slurry is maintained between 5% and 35% to ensure that the slurry in crystal collection channel 8 has transportability, separability, and stable washing performance. This recycling scheme integrates condensate recovery, residual liquid recirculation, and new material replenishment into the front-end liquid preparation section control. By using closed-loop water recovery and controlled mother liquor reuse, the overall water and heat consumption of the system is reduced, while maintaining the ion balance and concentration balance of the entire process system within the set window. During continuous operation, there is a clear correlation between the various control quantities: when the condensate recovery rate increases, the water replenishment of the raw material dissolution and degassing tank 1 decreases accordingly; when the residual liquid discharge increases, the new material replenishment rate and the raw material solution concentration adjustment are synchronously corrected; when the solid content of the crystal slurry increases, the feed flow rate of the slit-type directional purification chamber 2 is synchronously fine-tuned with the heat load, so that the entire unit can maintain a stable yield, stable purity and stable flow state under long-term operation conditions.

[0031] By fixing the solvothermal meniscus phase boundary inside the microcapillaries, limiting the desolvation location to within the anchoring plate channels, limiting the glycine surface growth location to the surface of the directional nucleation plate 10, and limiting the discharge location of the impurity-rich mother liquor to the upper end of the slit-type directional purification chamber 2, this technical solution establishes a continuous purification mechanism with clear spatial partitioning, defined mass transfer direction, and separation of product flow path and impurity flow path within the same purification unit. This mechanism structurally decomposes the problem of overlapping evaporation interfaces, nucleation regions, and impurity-rich regions in traditional open evaporation crystallization, enabling the simultaneous achievement of multiple requirements for low metal content, low salt content, low particle size, low liquid trapping, and high particle size consistency in the preparation of electronic-grade glycine within the same unit. Specific Implementation Example 2: Based on the technical solution of Specific Embodiment 1, an application case is further provided.

[0033] This unit was used to verify the operational stability, impurity removal capacity, and electronic-grade product quality of a single-module continuous purification unit under pilot-scale conditions. The purification unit employs a single-set slit-type directional purification chamber 2. The effective volume of the raw material dissolution and degassing tank 1 is 120L. The slit-type directional purification chamber 2 is 600mm long and 120mm wide. The slit channel spacing between the directional nucleation plate 10 and the phase boundary anchoring plate 11 is 2.0mm. The phase boundary anchoring plate 11 has a thickness of 1.8mm, a through-hole microcapillary diameter of 18μm, a pore length of 220μm, a pore surface density of 12000 pores / cm², an open porosity of 14%, a feed-side orifice wall contact angle of 42°, and a cooling-side orifice wall contact angle of 108°. The directional nucleation plate 10 uses an electropolished 316L stainless steel substrate, with a 120μm thick glycine seed layer covering 95% of the surface.

[0034] The initial purity of crude glycine was 99.10%, with sodium, potassium, calcium, iron, copper, nickel, and chloride ion levels at industrial-grade pretreatment levels. 70 kg of crude glycine and 230 kg of deionized water were added to the raw material dissolution and degassing tank 1. The mixture was first circulated at 38°C for 25 min, then heated to 63°C and maintained for 40 min to complete dissolution. Subsequently, vacuum degassing was performed at 22 kPa for 18 min, reducing the dissolved gas content to 0.42 mg / L. After primary filtration (2.0 μm) and secondary filtration (0.10 μm), the raw material solution entered the slit-type directional purification chamber 2 at a flow rate of 42 L / h from the lower end of the slit channel. The chamber temperature was maintained at 64°C, the solvent receiving chamber 3 temperature at 12°C, and the solvent receiving chamber 3 pressure at 16 kPa. The condensate collection rate remained stable at 5.8 L / h.

[0035] Table 1. Raw material conditions and structural groupings for Example 1 and Comparative Examples 1-3 ; Table 2 Core operating parameters of Example 1 and Comparative Examples 1-3 ; In Example 1, during operation, controller 9 controls the condensate flow rate, inlet and outlet temperatures of the cavity, solid content of the crystal slurry, and residual liquid conductivity in a linked manner. After 40 minutes of operation, crystal collection channel 8 begins to continuously discharge crystal slurry, and after 90 minutes, the solid content of the crystal slurry stabilizes at 20% to 22%. The residual liquid channel dynamically adjusts the discharge ratio based on online conductivity and online calcium and iron ion signals to maintain stable discharge from the impurity enrichment zone. Comparative Example 1 eliminates the heterogeneous wetting structure on the pore wall, Comparative Example 2 eliminates the seed layer, and Comparative Example 3 employs traditional vacuum evaporation and single recrystallization.

[0036] Table 3 Comparison of process stability and finished product quality between Example 1 and Comparative Examples 1-3 ; Table 4 Crystal morphology and post-processing properties of Example 1 and Comparative Examples 1-3 ; Table 3 shows that Example 1 exhibits the lowest levels of condensation flux fluctuation, pressure drop increase, and slurry fluctuation, with no crystallization blockage at the orifice. Table 4 shows that Example 1 has better D50 particle size, liquid adsorption amount, and post-wash conductivity than the comparative examples. These results indicate that heterogeneous wetting through microcapillaries can stabilize the meniscus phase boundary, and the 10 seed layers of the directional nucleation plate can preferentially convert supersaturation into plate surface growth, thereby enabling solvent removal, directional crystallization, and impurity removal to be synergistically achieved within the same continuous unit. Specific Implementation Example 3: Based on the technical solution of Specific Embodiment 1, an application case is further provided.

[0038] This system was used to verify the continuous operation capability and performance of the modular parallel scale-up system in downstream electronic chemical applications. It consists of three identical slit-type directional purification modules connected in parallel, sharing a common set of raw material dissolution and degassing tank 1, mother liquor balance tank, and condensate recovery main pipe. Each module's slit-type directional purification chamber 2 has a length of 1200 mm, a width of 250 mm, a channel spacing of 3.2 mm, a phase boundary anchoring plate 11 thickness of 2.5 mm, a through-hole microcapillary pore diameter of 28 μm, a pore length of 360 μm, a pore surface density of 9600 pores / cm², and an open porosity of 16%. All three directional nucleation plates 10 are made of high-purity alumina ceramic substrate, with a seed layer thickness of 180 μm and a coverage of 92%.

[0039] 160 kg of crude glycine and 540 kg of deionized water were added to a 650 L raw material dissolution and degassing tank 1. The mixture was first circulated at 42 °C for 30 min, then heated to 72 °C and maintained for 50 min to complete dissolution. The raw material solution was filtered through a 3.0 μm primary filter and a 0.20 μm secondary filter, and then evenly distributed to three modules via a distribution manifold. The feed flow rate for each module was 115 L / h, and the average linear velocity in the slit channel was 0.087 m / s. The temperature of the slit-type directional purification chamber 2 in all three modules was 73 °C, and the temperature of the solvent receiving chamber 3 was 9 °C. The uniform vacuum pressure on the cooling side was 20 kPa. The mother liquor balance tank controlled the reflux and discharge ratios based on the total conductivity and total reflux flow rate. The condensate recovery system maintained a total condensate collection rate of 52 to 55 L / h.

[0040] Table 5. Raw material indicators and modular operation parameters of Example 2 and Comparative Example 3 ; In Example 2, the controller 9 is divided into a total quantity coordination layer and a single-module correction layer. The total quantity coordination layer adjusts the total feed rate, total water replenishment rate, and high-impurity mother liquor discharge rate based on the total condensate output, the conductivity of the mother liquor balance tank, and the total crystal slurry volume. The single-module correction layer adjusts the feed distribution ratio and drain valve opening of each module based on the inlet temperature of each module, local pressure difference, residual liquid conductivity, and crystal slurry solid content. From the second hour of operation, the solid content of the crystal slurry in each module stabilizes at 22% to 27%, and the total slurry feed rate of the three centrifuges remains at 31 to 34 kg / h.

[0041] Table 6. Long-term operational stability data for Example 2 ; Table 7 Comparison of finished product quality and electronic chemical application performance between Example 2 and Comparative Example 3 ; ;

[0042] Table 6 shows that the fluctuations in condensation flux, pressure drop, and solid content of the slurry remained consistent during the 48-hour parallel operation of the three modules, indicating that modular scale-up maintained the phase boundary stability and surface growth stability within each module. Table 7 shows that the product of Example 2 outperformed the traditional process product in terms of metal ion content, anion content, particle number, average particle size, and downstream solution preparation and filtration stability, demonstrating that this technical solution can still maintain the cleanliness and application stability required for electronic-grade target products after large-scale scale-up.

[0043] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a reference structure" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An electronic-grade glycine purification unit based on solvothermal phase-interface sieving, characterized in that, The system includes a raw material dissolution and degassing tank (1), a slit-type directional purification chamber (2), a solvent receiving chamber (3), a phase boundary anchoring plate (11), a first temperature control jacket (4), a second temperature control jacket (5), a condenser (6), a residual liquid discharge channel (7), a crystal collection channel (8), and a controller (9). The phase boundary anchoring plate (11) is located between the slit-type directional purification chamber (2) and the solvent receiving chamber (3). The phase boundary anchoring plate (11) is provided with an array of penetrating microcapillaries, each penetrating microcapillary along the slit-type... The directional purification chamber (2) extends towards the solvent receiving chamber (3); the outlet of the raw material dissolving and degassing tank (1) is connected to the inlet of the slit-type directional purification chamber (2); the residual liquid discharge channel (7) is connected to the residual liquid outlet of the slit-type directional purification chamber (2); the crystal collection channel (8) is connected to the crystal outlet of the slit-type directional purification chamber (2); the condenser (6) is connected to the solvent receiving chamber (3); the first temperature control jacket (4) is located outside the slit-type directional purification chamber (2). The second temperature control jacket (5) is disposed outside the solvent receiving chamber (3); a directional nucleation plate (10) 10 is disposed inside the slit-type directional purification chamber (2), the directional nucleation plate (10) 10 and the phase boundary anchoring plate (11) are arranged opposite to each other and together define the slit flow channel; the controller (9) is connected to the first temperature control jacket (4), the second temperature control jacket (5), the condenser (6) 6 and the raw material dissolution and degassing tank (1) respectively, and is used to control the glycine aqueous solution in the slit-type directional purification chamber (2) to be in a heated state. The solvent receiving chamber (3) is in a cooled state, and a stable solvent thermal meniscus phase interface is formed in each penetrating microcapillary pore. Water molecules are vaporized through the solvent thermal meniscus phase interface and enter the solvent receiving chamber (3) and are condensed and recovered by the condenser (6). Glycine molecules form a controlled supersaturated region in the slit channel and crystallize and grow on the surface of the directional nucleation plate (10). Metal ion impurities, inorganic salt impurities and particulate impurities are retained in the slit-type directional purification chamber (2) and discharged through the residual liquid discharge channel (7).

2. The electronic-grade glycine purification unit based on solvothermal phase interface sieving according to claim 1, characterized in that, The pore diameter of the through-microcapillary is 5-60μm, the pore length is 80-600μm, the ratio of pore length to pore diameter is 4:1-30:1, the pore surface density is 1000-30000 pores / cm2, and the porosity is 8%-28%; the pore wall contact angle of the through-microcapillary near the slit-type directional purification chamber (2) is 20°-70°, and the pore wall contact angle near the solvent receiving chamber (3) is 95°-130°.

3. The electronic-grade glycine purification unit based on solvothermal phase interface sieving according to claim 1, characterized in that, The slit channels have a spacing of 0.5-6.0 mm, a length of 100-1500 mm, and a width of 20-400 mm; a glycine seed layer is fixedly disposed on the surface of the oriented nucleation plate (10), the glycine seed layer has a thickness of 20-500 μm, and the seed layer coverage is 70%-100%; The feed inlet of the slit-type directional purification chamber (2) is located at the lower end, the residual liquid outlet is located at the upper end, and the crystal outlet is located on the bottom side wall.

4. The electronic-grade glycine purification unit based on solvothermal phase interface sieving according to claim 1, characterized in that, The first temperature control jacket (4) controls the temperature of the glycine aqueous solution in the slit-type directional purification chamber (2) to be 45-85℃, the second temperature control jacket (5) controls the temperature of the solvent receiving chamber (3) to be 5-25℃, the pressure of the solvent receiving chamber (3) is 5-40kPa, the pressure of the slit-type directional purification chamber (2) is 20-120kPa, and the pressure difference between the slit-type directional purification chamber (2) and the solvent receiving chamber (3) is 2-25kPa.

5. The electronic-grade glycine purification unit based on solvothermal phase interface sieving according to claim 1, characterized in that, The raw material dissolving and degassing tank (1) is connected to a vacuum degassing component and a circulating pump. The vacuum degassing component controls the dissolved gas content in the raw material solution to be 0.1-2.0 mg / L. A primary filter and a secondary filter are sequentially installed on the discharge pipeline of the raw material dissolving and degassing tank (1). The filtration pore size of the primary filter is 1.0-5.0 μm, and the filtration pore size of the secondary filter is 0.05-0.45 μm.

6. The electronic-grade glycine purification unit based on solvothermal phase interface sieving according to claim 1, characterized in that, The residual liquid discharge channel (7) is equipped with a conductivity detector, an online metal ion detector and a discharge valve; the controller (9) controls the opening of the discharge valve according to the detection signals of the conductivity detector and the online metal ion detector, so that the discharge volume of the residual liquid discharge channel (7) accounts for 1%-20% of the inlet volume of the slit-type directional purification chamber (2); the condensate outlet of the condenser (6) 6 is connected to the raw material dissolution and degassing tank (1).

7. The electronic-grade glycine purification unit based on solvothermal phase interface sieving according to claim 1, characterized in that, The components in contact with the material in the raw material dissolving and degassing tank (1), slit-type directional purification chamber (2), solvent receiving chamber (3), phase boundary anchoring plate (11), primary filter, secondary filter, residual liquid discharge channel (7), crystal collection channel (8) and condenser recovery unit (6) are made of PFA, PTFE, quartz, alumina ceramic and electropolished 316L stainless steel; the phase boundary anchoring plate (11) is made of alumina ceramic, silicon nitride ceramic or sintered quartz.

8. The method for purifying electronic-grade glycine based on solvothermal phase interface sieving according to claim 1, characterized in that, The electronic-grade glycine product is obtained using the following steps: S1. Add crude glycine and deionized water to the raw material dissolving and degassing tank (1) to prepare a raw material solution with a glycine mass fraction of 8%-30%, and then heat the raw material solution to 45-85℃ and perform vacuum degassing. S2. The raw material solution obtained in S1 is filtered through a primary filter and a secondary filter in sequence, and then continuously introduced into the slit-type directional purification chamber (2) from the feed inlet at the lower end of the chamber. S3. Control the first temperature control jacket (4), the second temperature control jacket (5) and the condenser (6) to make the temperature of the raw material solution in the slit-type directional purification chamber (2) 45-85℃, the temperature of the solvent receiving chamber (3) 5-25℃, and the pressure of the solvent receiving chamber (3) 5-40kPa. A stable solvent thermal meniscus phase boundary is formed in the microcapillary pores, so that water molecules are vaporized and migrated to the solvent receiving chamber (3) through the solvent thermal meniscus phase boundary and are condensed and recovered. S4. During the process of S3, the flow rate in the slit channel is controlled to be 0.01-0.20 m / s, so that glycine is oriented to crystallize on the surface of the oriented nucleation plate (10)10, and metal ion impurities, inorganic salt impurities and particulate impurities are enriched in the uncrystallized mother liquor. S5. The residual liquid enriched with impurities is continuously discharged from the upper end of the slit-type directional purification chamber (2), and glycine crystal slurry is continuously discharged from the crystal outlet. The glycine crystal slurry is then separated into solid and liquid, washed and dried to obtain electronic grade glycine product.

9. The method for purifying electronic-grade glycine based on solvothermal phase interface sieving according to claim 8, characterized in that, The glycine seed layer on the surface of the directional nucleation plate (10) 10 in S4 has a thickness of 20-500 μm; in S5, the glycine crystals after solid-liquid separation are washed with deionized water at a temperature of 0-10℃ and a conductivity of 0.02-1.0 μS / cm. The amount of washing solution is 5%-30% of the mass of the wet crystals. After washing, the glycine crystals are dried at 40-80℃ and an absolute pressure of 5-50 kPa for 2-20 h.

10. The method for purifying electronic-grade glycine based on solvothermal phase interface sieving according to claim 8, characterized in that, The residual liquid discharged from S5 is returned to the raw material dissolution and degassing tank (1) and mixed with newly added crude glycine and deionized water to prepare a new raw material solution; the condensate obtained from the condensation and recovery in S3 is returned to the raw material dissolution and degassing tank (1); the method maintains the pH of the raw material solution at 5.70-6.30 under continuous operation, maintains the residual liquid discharge at 1%-20% of the liquid inlet of the slit-type directional purification chamber (2), and maintains the solid content of the crystal slurry at 5%-35%.

Images