126 results about "Crystallization Purification" patented technology

The invention discloses a high-salinity wastewater resource utilization method and device, belongs to the technical field of chemical engineering, and relates to wastewater treatment. The invention relates to a high-salinity wastewater resource utilization method which comprises the following steps: (1) deep removal of organic matters in a high-salinity system: realizing selective separation and removal of the organic matters in wastewater by using a synergistic effect of a flocculating agent and a catalyst; (2) mixed salt separation and recycling: realizing stable separation of sodium chloride and sodium sulfate through the design of MCR-nanofiltration-reverse osmosis multi-membrane coupling synergistic gradient coupling and reflux nesting; and (3) stable control of evaporative crystallization of a complex system: a scale inhibitor, humic acid and a defoaming agent are used, and fractional crystallization and purification are realized through high-temperature firing. According to the method, recycling circulating water can be saved, a large amount of sodium chloride and sodium sulfate are recycled as byproducts, COD and ammonia nitrogen are reduced, the recycling rate of sodium sulfate and sodium chloride is larger than 85%, and the water recycling rate is larger than 95%.

The application discloses a potassium fluorotantalate crystallization purification method, and relates to the technical field of tantalum hydrometallurgy and fluorotantalate crystallization purification. The method comprises the following steps: filtering a tantalum-containing fluorine acid solution, adding a potassium source and a tantalum-niobium separation type composite crystallization regulator, stirring and complexing, seed induction, controlled cooling crystallization, graded removal of the regulator, solid-liquid separation, and potassium fluoride containing fluorine acid washing to obtain primary purified potassium fluorotantalate crystals, and then redissolving the primary purified potassium fluorotantalate crystals in a fluorine-containing acid solution, correcting the K / Ta molar ratio, repeatedly regulating and crystallizing, graded removal of the regulator, washing, and drying to obtain high-purity potassium fluorotantalate. The regulator can reduce the entrainment of niobium impurities and reduce the residual amount of the regulator itself, thereby improving the purity of the product and the Ta yield.

The invention discloses a low-energy-consumption crystallization purification method of high-purity molten salt-grade potassium nitrate, and belongs to the technical field of purification of inorganic chemical materials. The method comprises the steps of raw material pretreatment directional impurity removal, multi-stage gradient crystallization, mother liquor graded circulation and low-temperature drying, in the raw material pretreatment stage, impurity concentration online detection and dynamic pH regulation are combined, a chelating agent, an oxidizing agent and an adsorption flocculant are added step by step, precise directional removal of metal impurities and suspended solids is achieved, and the product purity is improved; a multi-stage gradient crystallization process combining gradient temperature control and sectional controllable cooling is adopted, and the crystallization efficiency is improved in cooperation with a crystal form regulating agent; a mother liquor graded circulation and drying waste heat recovery system is matched, so that the mother liquor utilization rate is increased, and the production energy consumption is reduced.

The crystallization purification preparation system for 2, 6-dimethylnaphthalene comprises a suspension stirring crystallizer and a crystal filter, the suspension stirring crystallizer is connected to one end of the crystal filter, and the other end of the crystal filter is connected with a residual liquid tank and a static crystallizer; a mother liquid tank and a finished product tank are arranged on the first pipeline between the static crystallizer and the crystal filter; meanwhile, the residual liquid tank, the mother liquid tank and the static crystallizer are also respectively connected with a waste removal and discharge pipeline; wherein the suspension stirring crystallizer is connected with a cooling and heating all-in-one machine through a cooling and heating medium pipeline, and the static crystallizer is also connected with the cooling and heating all-in-one machine through the cooling and heating medium pipeline. According to the method, high-purity 2, 6-dimethylnaphthalene is obtained from low-value petrochemical raw materials by adopting a crystallization purification method.

The invention provides a preparation method for synthesizing lithium sulfide from industrial-grade lithium hydroxide and sodium sulfide, a preparation method for a solid electrolyte and a solid-state battery, and the preparation method for synthesizing lithium sulfide from industrial-grade lithium hydroxide and sodium sulfide comprises the following steps: dissolving an industrial-grade lithium hydroxide raw material, and sequentially carrying out oxidation, filtration, washing and drying to obtain lithium sulfide; sodium sulfide and a flocculating agent are added for precipitation and filtration, then sodium carbonate and barium nitrate are sequentially added for impurity removal and filtration, and a lithium hydroxide purified solution is obtained; reacting the sodium sulfide solid with dilute sulphuric acid to obtain hydrogen sulfide gas; hydrogen sulfide gas is introduced into the lithium hydroxide purification liquid for a reaction, and lithium sulfide slurry is obtained; evaporating, concentrating and crystallizing the lithium sulfide slurry, and centrifugally separating; and carrying out vacuum calcination on the crystal, and crushing to obtain lithium sulfide powder. Through oxidative conversion, chemical precipitation and crystallization purification, efficient and deep removal of impurities is realized, the problems that raw material components are complex and difficult to separate are solved, and the purity of lithium sulfide is improved.

This invention relates to the field of lithium battery technology and discloses a method for purifying lithium hexafluorophosphate by continuous flow crystallization. The method includes: (1) adding a first organic solvent to crude lithium hexafluorophosphate to dissolve it, preparing a saturated lithium hexafluorophosphate-organic solvent solution, filtering to remove insoluble matter, and obtaining a saturated lithium hexafluorophosphate solution; (2) feeding the saturated lithium hexafluorophosphate solution and the second organic solvent into a microchannel reactor for cooling using metering pumps, filtering the precipitated crystals, washing them with a cooled third organic solvent, and then vacuum drying. The lithium hexafluorophosphate precipitated by the method of this invention has high purity and stable quality, making it very suitable for industrial promotion and application.

The present application relates to a kind of preparation methods and systems of electronic grade dimethyl carbonate prepared from dimethyl oxalate, the method comprises the following steps: dimethyl oxalate is preheated and sent into decarboxylation reactor to carry out decarboxylation reaction, carbon monoxide, dimethyl carbonate and other light components are extracted from the top of decarboxylation reactor, and heavy components are extracted from the bottom of decarboxylation reactor;Carbon monoxide, dimethyl carbonate and other light components extracted are separated after gas-liquid, and liquid phase dimethyl carbonate is sent into rectifying column to carry out rectification purification;Electronic grade dimethyl carbonate product is obtained by crystallization purification in refrigeration crystallization device after rectification, and crystallization mother liquor returns rectifying column;Decarboxylation reactor is three-stage reaction tower, and rectifying section, reaction section, stripping section are sequentially from top to bottom.The present application is completely reacted by the design of three-stage decarboxylation reactor;Heavy components generated are extracted in real time, and catalyst stability is high;Electronic grade DMC is prepared by using rectifying column coupled with crystallization tower, and the yield of DMC is significantly improved.

The application provides a purification method and dichloroisocyanurate obtained by using the method. The purification method of dichloroisocyanurate comprises the following steps: repeatedly crystallizing crude dichloroisocyanurate obtained in a production synthesis process to obtain purified dichloroisocyanurate. The purification method of dichloroisocyanurate of the application utilizes the different melting points of dichloroisocyanurate and other impurities, and is designed to be repeatedly crystallized at different gradient temperatures. By adjusting the crystallization temperature and the crystallization time, the impurities in the dichloroisocyanurate can be removed. Compared with the crude distillation method, the obtained dichloroisocyanurate has higher purity, and is safer and easier to operate.

The invention relates to composite ceramic, a preparation method thereof, aluminum segregation purification equipment and an aluminum segregation purification method. The preparation raw materials of the composite ceramic comprise silicon nitride, lithium titanate and silicon carbide. The composite ceramic is high in mechanical property, high in thermal conductivity and good in chemical stability and can be used as a crystallization rod in aluminum segregation and purification equipment for segregation, crystallization and purification of aluminum, and the crystallization rod made of the composite ceramic has longer service life compared with a graphite crystallization rod, so that the replacement frequency of the crystallization rod can be reduced, and the production cost is reduced. And the cost of aluminum segregation extraction is reduced.

The invention discloses an o-methylbenzyl chloride production process and a production system thereof, and relates to the technical field of o-methylbenzyl chloride production, and the process comprises the steps of reaction raw material pretreatment, staged chlorination reaction, in-situ separation and real-time purification, o-methylbenzyl chloride crude product pretreatment, o-methylbenzyl chloride refining treatment, catalyst recovery and environmental protection treatment. The preparation method has the advantages that by improving the uniformity of free radical generation and the good dispersity of the initiator, the free radical generation sites and concentration in the reaction system are more uniform, and the occurrence of local over-reaction areas and incomplete reaction areas is reduced, so that the problems of excessive chlorination and raw material waste are reduced; the temperature, chlorine flow and illumination conditions are accurately controlled in the staged chlorination reaction, so that hydrogen atoms on benzyl carbon atoms are prevented from being continuously substituted, generation of byproducts such as o-methylbenzyl chloride is reduced, the purity of the target product o-methylbenzyl chloride is improved, and the requirement for subsequent multiple distillation or crystallization purification is reduced.

This invention relates to an extraction method for improving the bioavailability of tartrate tylosin. The method includes subjecting tartrate fermentation broth to a single acid-dissolution and alkali-precipitation treatment, followed by static crystallization to obtain crude tartrate. This crude tartrate is then subjected to extraction and back-extraction steps, followed by decolorization and ultrafiltration to obtain refined tartrate. Finally, it is spray-dried to obtain tartrate tylosin. This invention optimizes the extraction process of tartrate tylosin by combining a single acid-dissolution and alkali-precipitation crystallization purification process with extraction and back-extraction processes, effectively improving the bioavailability of tartrate tylosin.

The invention relates to the technical field of purification equipment, in particular to dibenzoyl tartaric acid low-energy-consumption purification equipment which comprises an equipment frame, a freezing crystallizing tank is rotatably connected to the equipment frame, a rotating seat is rotatably connected in the freezing crystallizing tank, and a mounting pipe is fixedly connected to one end of the rotating seat. A mounting pipe is arranged on the equipment frame, a crystal separation net seat is movably inserted into one end of the mounting pipe, an adjusting scraping mechanism is rotatably connected in the freezing crystallizing tank, a liquid discharge pipe is fixedly connected to one end of the freezing crystallizing tank in a penetrating manner, and a solution pre-cooling seat is fixedly arranged on the equipment frame. And automatic separation is carried out in a manner of overturning the freezing crystallization tank and rotating the crystallization separation net seat, so that the complex process of taking out crystal substances is avoided, the freezing environment is kept, the risk of melting the crystal substances is reduced, the separation efficiency is improved, the energy consumption is reduced, and the product purity is improved. The overall efficiency and effect of freezing crystallization purification are greatly improved.

The invention discloses an efficient synthesis method of brexpiprazole, which comprises the following steps: taking 4-bromo-benzothiophene and N-Boc-piperazine as initial raw materials, under the protection of nitrogen, carrying out reaction by using a supported catalyst to prepare 4-Boc piperazine benzothiophene, and then carrying out acidolysis to obtain 4-piperazine benzothiophene hydrochloride; the method comprises the following steps: reacting 3, 4-dihydro-7-hydroxy-2 (1H) quinolinone with 1-bromo-4-chloro-butane to generate 3, 4-dihydro-7-(4-chlorobutoxy)-2 (1H)-quinolinone, and then converting the 3, 4-dihydro-7-(4-chlorobutoxy)-2 (1H)-quinolinone into 7-(4-chlorobutoxy)-2 (1H)-quinolinone; then condensing with 4-piperazine benzothiophene hydrochloride to obtain a crude product of brexpiprazole; and finally, crystallizing and purifying for multiple times to obtain high-purity brexpiprazole. According to the preparation method disclosed by the invention, 4-bromo-benzothiophene and N-Boc-piperazine are taken as starting raw materials, and high-purity brexpiprazole is prepared by optimizing selection of a catalyst and conditions of each step and through an excellent purification process.

The utility model discloses a racemic p-hydroxyphenylglycine recrystallization device, and belongs to the technical field of chemical production devices and crystallization purification. The device comprises a decoloration and impurity removal kettle, a filter, a crystallization kettle, a centrifugal machine and the like, and has the innovation points that 1, a precise microporous membrane filter is additionally arranged in the decoloration and impurity removal process of the DL-hydroxyphenylglycine, and a rubber and plastic cotton heat preservation layer is additionally arranged on the outer surface of the microporous membrane filter; 2, a stirrer of the crystallization kettle is arranged into a double-layer structure, and an upper-layer stirring paddle is arranged into a rake shape; 3, an airflow control valve is additionally arranged between the crystallization kettle and the bottom valve; according to the technical scheme, the DL-p-hydroxyphenylglycine recrystallization device effectively solves the problem that tiny impurity points still exist after mother liquor is filtered, the problem that a pipeline is blocked due to temperature reduction in the midway of filtering, and the problem that a discharge valve of a crystallization kettle is easy to block; the device also has the characteristics of high production efficiency, high product purity and convenience in operation.

The invention discloses a high-purity synthesis method of 18-crown ether-6, which is characterized by comprising the following steps: S1, in an industrial microwave reactor provided with a special nano-material lining, uniformly mixing p-toluene sulfonic acid dihydric alcohol ester, dihydric alcohol, an alkaline substance and a composite solvent, and reacting at 0-40 DEG C for 0.2-5 hours to obtain a reaction product; in the reaction process, the reaction is promoted by virtue of the special property of the nano-material lining; and S2, after the reaction is finished, obtaining a high-purity target product 18-crown ether-6 through a specific post-treatment process. According to the method, the industrial microwave reactor provided with the special nano-material lining is adopted for reaction, the classical Williamson etherification reaction is accelerated through microwaves, the reaction time is greatly shortened, the reaction speed is greatly increased compared with that of a conventional method, meanwhile, the special purifying agent acetonitrile is added for crystallization purification, the purity of the product can be effectively improved, and the method is suitable for industrial production. The purity of the 18-crown ether-6 is not lower than 99.5%.

The invention relates to bio-based taurine and a preparation method thereof, and the preparation method of the bio-based taurine comprises the following steps: mixing sulfoalanine with a ketone catalyst to carry out a decarboxylation reaction, and after the reaction is finished, carrying out separation and crystallization to obtain the bio-based taurine. According to the preparation method disclosed by the invention, the sulfoalanine is used as a raw material, the ketone catalyst is adopted for decarboxylation reaction, impurities are not easy to generate, the taurine can be obtained only through crystallization and purification, the operation is simple, the yield is relatively high, and industrial production is facilitated.

The invention belongs to the technical field of optical crystal preparation, and provides a magnesium fluoride crucible descending type directional crystallization purification method for ultraviolet optical crystal manufacturing. Magnesium fluoride raw materials are placed in a vacuum furnace to be subjected to desorption pretreatment, then the raw materials are fused, subjected to heat preservation and homogenized, first-process directional crystallization is achieved through descending displacement of a crucible relative to a hot area, a first ingot body is obtained, impurities are enriched towards the tail end along with the crystallization process, and only a local section of the enriched end is heated and remelted to form a controlled molten pool; the middle-section main body is kept in a solid state; the temperature gradient direction is reversed by switching the power ratio of a heating area, the molten pool is subjected to second-process directional crystallization in the opposite direction to form a second ingot body, the second ingot body is axially cut in a segmented mode, a middle purification section is reserved to serve as a high-purity raw material, and the middle purification section can be repeatedly executed in the same furnace to obtain a raw material section; according to the method, segregation enrichment and reverse ending are completed in a clean atmosphere, and the method is suitable for manufacturing magnesium fluoride crystals for ultraviolet optical elements.

The invention relates to a refining and purifying method of entecavir. The method comprises the following steps: adding an entecavir crude product as shown in a formula I into a solvent 1, dissolving, adding into a solvent 2, crystallizing for the first time, filtering, adding a filter cake into a solvent 3, and crystallizing for the second time to obtain the entecavir pure product as shown in the formula I. According to the entecavir crystallization purification method, the obtained entecavir pure product is good in product yield and high in purity, the purity of the product can reach 99.8% at most, and especially isomer impurities and impurity C which are difficult to remove can be rapidly and effectively removed. The solvents used in the refining and purifying method are all green, environment-friendly and pollution-free reagents, the cost is low, the technological process is simple to operate, and industrial production is facilitated.

The invention discloses a crystallization purification method of indene in C9 petroleum resin, which comprises the following steps: S1, pretreating the C9 petroleum resin to obtain concentrated indene; s2, mixing the concentrated indene with a solvent I, performing primary cooling crystallization, and filtering after heat preservation to obtain crystals and filtrate; s3, mixing the crystals with a solvent II, carrying out secondary cooling crystallization, carrying out heat preservation, and filtering to obtain a filter cake; and S4, dissolving the filter cake, and carrying out negative pressure distillation to remove the solvent so as to obtain indene. According to the method, low-temperature crystallization is adopted, target substances can be selectively separated out, impurities are effectively removed, and a C9 petroleum resin mixture with large solubility difference is separated. And moreover, the crystals cannot be caked or caked during precipitation, the dispersion difficulty is low, filtration is easy, and the process difficulty is reduced.

The invention belongs to the technical field of high-value utilization of organic wastes, and particularly relates to a method for high-value utilization of phenolic tar. According to the method, the phenol tar is subjected to alcoholysis, alkylation, steam stripping, rectification, melt crystallization purification and other procedures to obtain high-added-value fine chemical products such as p-xylylene ether and anisole, and the residual tar after steam stripping can be continuously used as fuel to be incinerated to produce steam. According to the method disclosed by the invention, the hydroquinone in the phenol tar can be reacted and converted, the phenol tar with low polymerization degree can be alcoholyzed into phenol, hydroquinone and a small amount of catechol, part of phenolic compounds can be etherified with methanol and then converted into p-xylylene ether and anisole through alkylation, and according to measurement and calculation, the content of the p-xylylene ether in the phenol tar can be measured and calculated, and the content of the p-xylylene ether in the phenol tar can be measured and calculated. According to hydroquinone corresponding to the generated p-xylylene ether, the phenol tar can be converted into hydroquinone with the weight being 10% or above of the weight of tar through alcoholysis by deducting the original hydroquinone amount in the phenol tar, and therefore high-value utilization of the phenol tar is achieved.

The invention provides a waste salt treatment process and system based on a melt crystallization method, the waste salt treatment process is a process combining pulling crystallization, zone condensation and cold finger / cooling plate crystallization, and matrix salt is recovered from a chloride molten salt system containing strontium element and / or barium element and / or cesium element. The invention aims to solve the problems that the treatment scale and the product purity are difficult to consider at the same time, the volatilization loss is serious, and dual targets are difficult to realize under complex working conditions in the existing dry post-treatment waste salt melt crystallization purification technology. A waste salt melt crystallization purification technology which can adapt to complex working conditions, give consideration to high purification efficiency and high resource recovery rate and meet the large-scale treatment requirement is researched and developed, radioactive waste salt containing splitting elements is treated through process fusion, efficient purification of the waste salt is finally achieved, and the high removal rate and recovery rate are achieved.

The present disclosure relates to a method for producing high-purity phosphoric acid from low-purity phosphoric acid by forming pure phosphoric acid crystals using crystallization purification through quantum coupling of phosphoric acid. In particular, the present disclosure relates to a method for producing phosphoric acid capable of obtaining high-purity phosphoric acid from low-grade phosphoric acid economically and industrially by obtaining pure crystals from a phosphoric acid raw material containing a large amount of impurities through activating quantum coupling of phosphoric acid at a temperature above zero (0° C. or higher).

The application belongs to the technical field of organic synthesis and specifically relates to a preparation process of high-efficiency taurine. The process specifically comprises the following steps: S1, raw material solution preparation and mother liquor threshold reuse; S2, construction of an aminolysis selective chemical environment; S3, aminolysis reaction; S4, deamination and clarification filtration; S5, segmented acidification-crystallization coupling; S6, crystal throwing and controlled cooling crystallization; S7, solid-liquid separation, washing and drying; and S8, mother liquor threshold detection and closed-loop reuse. The application constructs an aminolysis selective control, acidification-crystallization purification and mother liquor threshold reuse synergistic closed-loop process, stably controls a reaction system, dynamically determines an end point, and inhibits by-product generation from the source; segmented acidification and temperature-controlled crystallization are adopted to improve the purity of crystals and the first-time pharmaceutical-grade qualified rate; and the mother liquor is recycled according to a multi-index threshold access, thereby blocking impurity accumulation.

The invention belongs to the technical field of purification, and particularly discloses an NMP (N-Methyl Pyrrolidone) purification method, which comprises the following steps of: removing metal ions in synthesized NMP through metal ion removal equipment, treating moisture in the NMP through moisture removal equipment, and removing particulate matters in the NMP through filtering equipment; then the NMP enters a first crystallization tower, and a liquid phase in the first crystallization tower enters a first crystal collection tank; the NMP in the first crystal collecting tank enters a second crystallization tower, and a liquid phase in the second crystallization tower enters a second crystal collecting tank; the NMP after the crystallization and purification process enters a first sweating rectification tower, and a crystalline phase in a tower kettle is heated and melted and then enters a first sweating rectification collection tank; nMP in the first sweating and rectifying collecting tank is conveyed into a second sweating and rectifying tower, and a crystal phase in a tower kettle is heated and melted and then enters the second sweating and rectifying collecting tank. All detection indexes of the NMP treated by the purification method reach the indexes of a G4-grade product, and the application of the NMP in the field of high-end semiconductors is met.

The invention discloses a nickel-based catalyst for catalyzing ethylene copolymerization to prepare a photoresponse polymer as well as a preparation method and application of the nickel-based catalyst. The method comprises the following steps: under the condition of strict humidity and oxygen control, carrying out coordination reaction on a functionalized phosphono-phenol ligand and a picolyl nickel precursor, controlling the coordination process of a metal center through step-by-step charging, carrying out solid-liquid separation on a reaction mixture, and carrying out gradient crystallization purification by adopting a mixed solvent system to obtain the high-purity nickel complex catalyst. According to the invention, ethylene and an acrylate monomer are catalyzed by a phosphine phenol nickel catalyst with electronic effect regulation and control to carry out copolymerization, and a functional polyolefin material with photoresponse is synthesized. The obtained copolymer can be well combined with dye in the dyeing performance, so that the dyeing process is more uniform and firmer, and wide prospects are provided for application of the copolymer in the industries of spinning, printing and dyeing and the like. And the adhesive force of the material is also effectively improved, so that the polymer has potential application value in the fields of adhesives, coatings and the like.

The invention relates to the technical field of fine chemical engineering, in particular to a preparation method of high-purity barium chloride. The method comprises the following steps: firstly, grafting an amino group on nano silicon dioxide and further synchronously introducing a hydrophobic chain and a phosphate group to prepare a difunctional surfactant with dispersion and impurity pre-adsorption functions for pretreating a witherite raw material; then calcining and dissolving with acid to obtain a crude solution, and sequentially carrying out multi-mechanism deep impurity removal and vacuum crystallization purification through barium hydroxide alkali adjustment hydrolysis, a targeted complexing agent and the like, so as to finally obtain high-purity barium chloride. According to the method disclosed by the invention, various impurities are efficiently and deeply removed through the cooperation of the whole processes of raw material pretreatment, targeted complexing and crystallization washing, the purity of the obtained barium chloride can reach 99.99% or above, the process flow is stable, and the yield is relatively high.

The application discloses a method for converting diacylated by-product into monoacylated product in the synthesis of fluoxastrobin, and belongs to the field of pesticides and intermediates. The method can effectively recover fluoxastrobin in a crystallization mother liquor and convert diacylated by-product, which is difficult to avoid in the synthesis process, into monoacylated product. The diacylated by-product and fluoxastrobin are close in polarity, and are difficult to remove by a conventional recrystallization method. In the application, the crystallization mother liquor containing the diacylated by-product and fluoxastrobin is dissolved in an organic solvent, a base is quantitatively introduced, the diacylated by-product is converted into monoacylated fluoxastrobin, the reaction solution is concentrated and recrystallized to purify, and the monoacylated product is obtained. In the application, the diacylated by-product is converted into the target product, and another by-product with stronger polarity is generated at the same time, which can be easily separated by recrystallization to obtain the target product with high purity. The process operation is simple, the conditions are mild, the separation yield is high, and the application has important significance for reducing three wastes, reducing cost and improving product quality.

The continuous production device is characterized in that a pH buffering agent storage tank of the continuous production device is sequentially connected with a crystallization purification device through a pipeline, the crystallization purification device is connected with a residue discharging tank, buffering tanks are arranged among the crystallization purification device, a first mixing device and a second mixing device, and the second mixing device is connected with a waste liquid collecting tank; the solubilizer storage tank is sequentially connected with the resin tower, the buffer tank, the filtering device and the first mixing device through pipelines; the resin tower is provided with a resin inlet and a solid waste temporary storage tank, and a buffer tank is arranged between the resin tower and the first mixing device; a pipeline of the electronic-grade phosphoric acid storage tank is sequentially connected with a dilute phosphoric acid storage tank, a filtering device and a second mixing device; the top of the dilute phosphoric acid storage tank is connected with the ultrapure water storage tank, and a phosphoric acid concentration detector is arranged in the dilute phosphoric acid storage tank; and the etching inhibitor storage tank is sequentially connected with the purification device, the buffer tank, the filtering device and the second mixing device through pipelines. The device deeply purifies the raw materials, improves the quality of the etching liquid and reduces the production cost.

This invention discloses a vacuum crystallization purification process for menthyl benzoate, comprising the following steps: S100, feeding; S200, cooling; S300, centrifugation. The parameter control process in step S200, cooling, specifically includes the crystallization temperature range, vacuum degree, methanol reflux flow rate, reflux methanol temperature, condenser medium, temperature rebound time, two-stage slow cooling method, multi-stage cooling method, and purity control of the menthyl benzoate raw material. This invention utilizes a rapid cooling method involving vacuum absorption and methanol reflux. Through precise temperature control, the system enters a transient stable state of crystallization before crystallization, where supersaturation and dissolution saturation are in equilibrium. Through two-stage slow cooling and multi-stage cooling stages, the system gradually enters a supersaturated solution state. Due to the precise control of the saturation-supersaturation-crystallization state, impurities cannot crystallize, thus achieving deep purification and obtaining a high-purity crystalline product.

The utility model discloses a stirring device and a crystallization purification system, and solves the technical problems of insufficient impurity diffusion and low segregation purification efficiency in the purification process of a crystallization method in the prior art. A stirring device comprises a support, two lifting mechanisms, a stirring mechanism, a water bath mechanism and a driving mechanism, and the stirring mechanism comprises a stirring column and a spiral piece arranged on the stirring column; the water bath mechanism is correspondingly communicated with the water bath inlet and the water bath outlet; the driving end of the driving mechanism is connected with the stirring column to drive the stirring column to rotate; under the condition that the lifting mechanism drives the stirring mechanism to ascend, the driving mechanism drives the stirring mechanism to rotate in a first direction; and under the condition that the lifting mechanism drives the stirring mechanism to descend, the driving mechanism drives the stirring mechanism to rotate in a second direction opposite to the first direction. According to the stirring column, under the combined action of the lifting mechanism and the driving mechanism, the vertical stirring speed and the rotating speed of the stirring column are controlled, and the stirring efficiency and the segregation effect are improved.