535 results about "Re crystallization" patented technology

The invention relates to a purification method of penta (dimethylamino) tantalum, and relates to the technical field of purification of amino metal compounds. In a standard glove box with the oxygen content lower than 2 ppm and the water content lower than 0.01 ppm, taking a proper amount of sublimated crude product penta (dimethylamino) tantalum, putting the sublimated crude product penta (dimethylamino) tantalum into a dry and clean sample bottle, adding a solvent after water and oxygen removal to dissolve the penta (dimethylamino) tantalum, and filtering; and then cooling and crystallizing, slowly reducing the temperature until crystals are separated out, and slowly crystallizing to generate faint yellow micro-transparent crystals. After crystallization is completed, filtering is conducted again in a low-temperature state, and crystals are dried in vacuum. And after the mother liquor is desolventized to evaporate out the solvent, the recovered crude product penta (dimethylamino) tantalum can be sublimated and recycled again.

To provide a method which enables inexpensive production with a high yield of lithium hydroxide with a low amount of impurities such as sodium from lithium-containing water including a lithium ion and a chloride ion.SOLUTION: A production method of lithium hydroxide includes: a crystallizing step of crystallizing lithium hydroxide (LiOH) from lithium-containing water including a lithium ion and a chloride ion; a solid-liquid separation step of performing solid-liquid separation treatment of concentrated liquid including the LiOH to obtain the LiOH as a solid product and filtrate; a carbonation step of producing lithium carbonate from the filtrate by carbonation; a lithium carbonate recovery step of evaporating at least a part of ammonia from a mixed liquid obtained in the carbonation step and performing solid-liquid separation treatment of the resultant treated liquid to obtain lithium carbonate as a solid product; a lithium hydroxide production step of converting the obtained lithium carbonate into LiOH followed by solid-liquid separation treatment to obtain an aqueous LiOH solution (1) as a liquid component; and a recrystallizing step of crystallizing LiOH from the aqueous solution (1).SELECTED DRAWING: Figure 2

The invention discloses a method for realizing pollution reduction and carbon reduction by phosphogypsum recycling. The method comprises the following steps: (1) washing phosphogypsum with water to remove soluble impurities, neutralizing residual acid, and calcining and activating; (2) pretreatment of the landfill leachate: magnesium salt and phosphate are added, the pH of the landfill leachate is adjusted, and free ammonia NH3 is released through low-temperature heating; (3) the pretreated landfill leachate is sprayed to capture CO2 in the flue gas, and a (NH4) 2CO3 solution is obtained; (4) fully mixing a (NH4) 2CO3 solution with the pretreated ardealite, and controlling the reaction conditions in a closed reactor, so that the ardealite and (NH4) 2CO3 are subjected to a heterogeneous reaction to generate CaCO3 and (NH4) 2SO4; and (5) product purification: carrying out solid-liquid separation on the mixed solution by adopting a multi-stage crystallization process to obtain a building material, and carrying out gradient cooling and recrystallization purification on the filtrate to obtain the nitrogen fertilizer. According to the method, recycling of the landfill leachate and the ardealite is achieved, and CO2 in the flue gas is efficiently removed.

The invention belongs to the technical field of preparation of semiconductor high-temperature protective coatings, and particularly relates to a chemical vapor infiltration method for preparing a low-residual-stress SiC high-temperature-resistant protective coating. A positive pressure chemical vapor infiltration technology is adopted, an MTS-H2 system is selected as a precursor, the molar ratio (MTS: H2 = 0.01-1) of the MTS-H2 system to the precursor is controlled, and when the working pressure is 100-400 KPa and the temperature is 1000-1600 DEG C, the SiC high-temperature-resistant protective coating which is low in residual stress and compact in structure is deposited on the surface of a recrystallized silicon carbide matrix. The SiC protective coating prepared by adopting the method is compact in structure, relatively low in residual stress and good in combination with a recrystallized silicon carbide matrix, and can play an excellent high-temperature protection role on the recrystallized silicon carbide matrix.

The invention provides a method for preparing FAPbBr3 quantum dots, which comprises the following steps: S1, preparation of a precursor solution: respectively dissolving a lead source precursor, a bromine source precursor and acid in water and stirring to obtain the precursor solution; s2, formation of nucleation sites: adding an FA precursor into the precursor solution prepared in the step S1, stirring, and reacting and crystallizing in water to form floccules capable of being used as the nucleation sites; s3, construction of a substrate layer: adding silane into the solution prepared in the step S2, stirring, heating and drying to obtain a FAPbBr3-coated SiO2 quantum dot crude product, and coating the exterior of FAPbBr3 with SiO2 generated by hydrolysis of the silane in an acidic solution to serve as the substrate layer; s4, ball-milling recrystallization: carrying out ball-milling recrystallization on the FAPbBr3-coated SiO2 quantum dot crude product prepared in the step S3; wherein the object of ball milling is a substrate layer, and the object of recrystallization is FAPbBr3 quantum dots. The solvent of the system is an aqueous solution, so that the problems of recycling, discharging and the like of organic solvents are solved.

The invention belongs to the technical field of forest chemical industry and natural perfume extraction and separation, and particularly discloses a superheated steam distillation separation and recovery method for perfume components in cinnamon oil rectifying still residues. The method comprises the following steps: processing the cinnamon oil rectifying still residues by adopting a steam distillation method taking normal-pressure superheated steam as a desorption medium, carrying out condensation cooling and phase separation on distilled oil-water mixed gas, and collecting oily liquid or crystalline solid containing cinnamon spice components, and carrying out one or more physical isolation methods such as freezing crystallization, vacuum fractionation or rectification, recrystallization and the like to obtain natural cinnamon monomer spices such as o-methoxycinnamaldehyde, o-methoxycinnamic acid, phenethyl alcohol and the like. The method has the advantages of low equipment investment, simple and feasible operation, low production cost, clean and pollution-free process, good operation safety, high industrial application feasibility and the like.

The invention belongs to the technical field of active substance preparation, and particularly relates to a preparation method and application of high-purity rare ginsenoside CK. The high-purity rare ginsenoside CK with the content exceeding 95% is finally produced through the steps of combined enzymolysis, ultrafiltration, nanofiltration, multiple crystallization and the like, the production efficiency and purity of the rare ginsenoside CK are improved through the preparation method, only ethyl alcohol and water are used as solvents in the whole process, it is guaranteed that the technology is green and environmentally friendly, and the method is suitable for industrial production. The method has the advantages of simple operation, no use of harmful chemical solvents, great reduction of environmental pollution, realization of the significant cost advantage in the whole production process due to repeated use of equipment and solvents, suitableness for large-scale industrial application, and wide market prospects and economic benefits.

The invention belongs to the technical field of chemical synthesis, and relates to a method for continuously synthesizing 4-bromo-2-p-chlorophenyl-5-trifluoromethyl pyrrole-3-nitrile by a microchannel reactor, which comprises the following steps: pumping a substrate solution to a first plate type micro-reaction module; respectively pumping the bromination reagent solution to a first plate type micro-reaction module, a second plate type micro-reaction module and a third plate type micro-reaction module to obtain a reaction base solution; the reaction base solution is introduced into a fourth plate type micro-reaction module, n-heptane is pumped to the fourth plate type micro-reaction module and a fifth plate type micro-reaction module, deionized water is pumped to the fourth plate type micro-reaction module and the fifth plate type micro-reaction module, and extract liquor is obtained; and carrying out separation, evaporation recovery and recrystallization to obtain a finished product. Through the multi-stage series design of the micro-channel reactor, catalytic bromination replaces traditional bromine oxidation and reaction-extraction in-situ integration, and the three major problems of low efficiency, serious pollution and poor safety of an intermittent process are solved.

The present invention discloses a preparation method of high-purity amino gallium, indium, and aluminum compounds, belonging to the technical field of semiconductor chips, and comprising the following steps: The first step is to prepare a lithium dimethylamide n-hexane suspension; the second step is to prepare one of crude tris(dimethylamino)gallium dimer, crude tris(dimethylamino)indium dimer, and crude tris(dimethylamino)aluminum dimer; the third step is to purify the crude tris(dimethylamino)metal compound by stepwise cooling recrystallization to obtain high-purity amino gallium, indium, and aluminum compounds; the present invention purifies the crude tris(dimethylamino)metal compound by stepwise cooling recrystallization, which not only has high efficiency and simple process, but also has a moderate crystallization rate of the product during the recrystallization process, will not form impurity encapsulation, has good crystal form of the product, and the purity is ≥99.9999% (6N), meeting the purity requirements for ALD / CVD film deposition of semiconductor chips.

The invention discloses a method for preparing copper sulfate from PCB etching liquid, and belongs to the technical field of PCB etching liquid treatment.The method comprises the following steps that alkaline PCB etching waste liquid and acidic PCB etching waste liquid are mixed to obtain basic copper chloride precipitate; reacting the basic copper chloride precipitate with concentrated sulfuric acid to obtain a copper sulfate crude product; adding a hydrogen peroxide solution into the copper sulfate crude product solution, stirring and reacting for 0.5-2 hours, adding a precipitator to adjust the pH value to 3.5-4, and carrying out solid-liquid separation to obtain an impurity-removed solution; the impurity removal solution is introduced into an adsorption column filled with modified activated carbon, then evaporation concentration, cooling crystallization and reduced-pressure suction filtration are carried out, and copper sulfate is obtained.According to the method, the processes of acid-base neutralization, oxidation impurity removal, adsorption impurity removal and recrystallization are adopted, and the low-cost and efficient recovery and purification technology is achieved; and the recovery efficiency is improved to the maximum extent and the cost is controlled while the high purity of the product is ensured.

The invention provides a method for preparing electronic-grade copper oxide by using circuit board acidic etching waste liquid, and belongs to the field of copper resource recovery. The method comprises the following steps: sequentially carrying out impurity removal, concentration crystallization, salt-alkali reaction and cleaning on the circuit board acidic etching waste liquid, and collecting to obtain a copper hydroxide crude product; dissolving and recrystallizing to obtain a copper hydroxide refined product; a carbonized ammonia water solution is added to react with the copper hydroxide refined product, and ammonia cupric carbonate is obtained after adsorption and purification; adding a surfactant and a zinc salt additive, and stirring; drying to obtain modified basic cupric carbonate; carrying out selective etching on the modified basic cupric carbonate by adopting dilute acid to obtain basic cupric carbonate particles; and calcining the basic cupric carbonate particles at 300-500 DEG C to obtain the copper oxide powder with the honeycomb structure. According to the method, on the basis of the basic step of recovering copper resources from the circuit board acidic etching waste liquid, the treatment steps of purification, grain refinement, porous etching and the like are added, so that the purity and the activity performance of a final copper oxide product are improved, and the electronic-grade copper oxide is prepared.

The invention belongs to the technical field of perovskite solar cell material preparation, and particularly provides a simple preparation method of high-purity formamidine hydriodate with controllable crystal form, which comprises the steps of feeding, concentrating, washing, dissolving, crystallizing, washing, drying and the like. The method can be used for synthesis in a room-temperature laboratory, has few steps, is simple to operate, and obviously reduces the difficulty in process production. The crystal is separated out by cooling instead of a poor solvent for recrystallization, and the crystal form of the product can be controlled simply by a simple programmed cooling program with high operability. And meanwhile, by adding the washing procedure, the recrystallization frequency is reduced, the use of an organic solvent is greatly reduced, the post-treatment complexity of the product is also reduced, and the phenomenon that the product is heated and exposed to light in the post-treatment process to generate impurities is effectively avoided.

The invention provides a bio-based crude terephthalic acid hydrofining method, and belongs to the technical field of terephthalic acid hydrofining. The method comprises the following steps: carrying out recrystallization pretreatment on bio-based crude terephthalic acid, mixing the pretreated bio-based crude terephthalic acid with a solvent, adding a catalyst, carrying out a hydrofining reaction, replacing the solvent after the reaction is finished, carrying out recrystallization treatment on a hydrofined product, washing with water, and drying to obtain refined terephthalic acid, the method disclosed by the invention has the advantages of high impurity removal rate, mild reaction conditions and small process pollution, the refining of the bio-based crude terephthalic acid is realized, the obtained terephthalic acid can meet the requirements of an existing industrial method, and the concentration of impurities p-carboxybenzaldehyde is less than or equal to 25ppm and the concentration of methyl benzoic acid is less than or equal to 180ppm.

The invention relates to a synthesis process of an omarigliflozin intermediate, and belongs to the technical field of drug synthesis, one-step efficient conversion is adopted in the process of synthesizing the omarigliflozin intermediate, p-bromophenylhydrazine hydrochloride is used as a starting raw material, and a target product is obtained through indole cyclization, alkali precipitation and acidification crystallization. Toluene plays a role in cyclization and dehydration in a high-temperature reflux process, in a purification process of alkali precipitation and acidification crystallization, a sodium hydroxide aqueous solution is utilized to hydrolyze and convert a product into water-soluble sodium salt, the water-soluble sodium salt enters a water phase, a toluene layer containing a large amount of organic impurities and the water phase are layered in a standing and layering process, and the organic impurities in the toluene layer are removed; the preparation method comprises the following steps of: preparing a sodium salt, acidifying in a water phase by using hydrochloric acid, changing the sodium salt form of the product into an acid form, and crystallizing from the water phase, which is equivalent to recrystallization purification, so that the prepared product has higher purity, the purity is stabilized at 98% or above, and the purity of the product can meet the quality standard of medical intermediates.

The invention relates to a method for purifying an electronic-grade sulfonium salt photoacid generator. The method comprises the following steps: heating, preparing a photoacid generator stock solution, purifying through ion exchange resin, cooling, recrystallizing, carrying out solid-liquid separation, washing crystals and the like to obtain the high-purity photoacid generator, so that the metal content in the photoacid generator can be effectively reduced, the single metal content is less than 5ppb, and the yield is up to 80-90%. And mother liquor is collected and purified by resin and can be used for preparing photoacid stock solution again. The operation effectively reduces the use of an organic solvent and the generation of wastewater, can further improve the recrystallization yield, and meets the requirements of green and sustainable development.

The invention discloses a preparation process of high-purity dotenorad, and belongs to the technical field of organic synthesis route design and raw material medicine and intermediate preparation. Benzothiazole is used as a starting material, reduction, acylation, amide condensation, oxidation, demethylation and other reactions are sequentially carried out, a dotenorad crude product is synthesized, and the required crystal form is obtained through recrystallization. The raw materials of the preparation method are cheap, easy to obtain and high in stability, the defect that the raw materials of other preparation processes are poor in stability is overcome, and the preparation method is convenient to operate and suitable for industrial production; the total yield of the prepared dotenorad in each step is 66.80%, and the purity of the dotenorad can reach 99.99%.

The invention belongs to the technical field of food processing, and particularly relates to a preparation method and application of resistant starch. By optimizing drying process parameters (temperature, humidity control and the like), the damage of spray drying (high-temperature hydrogen bond damage), vacuum freeze drying (water loss of a crystal channel caused by sublimation of ice crystals) and traditional hot air drying (untimely loss of bound water caused by unregulated moisture distribution) to the starch double-helix structure in the prior art is effectively avoided. By maintaining a moisture environment required by recrystallization of starch molecules, ordered arrangement of starch chains is promoted, the relative crystallinity of the resistant starch is remarkably improved, and the problems of incomplete crystal structure and limited digestion resistance caused by an existing drying process are solved; and a key technical support is provided for large-scale application in the fields of baked foods, meal replacement products, pharmaceutical preparations and the like.

To provide a method for manufacturing a graphite crucible hard to be exhausted even when put at high temperature.SOLUTION: A method for manufacturing a single crystal growth graphite crucible, capable of growing the single crystal on the main surface of a seed crystal substrate by a sublimation recrystallization method comprises: the molding step of molding a raw material including coke mainly constituted of needle coke and binder pitch; the calcination step of calcining the molded molding to obtain a calcined product; the first impregnation calcination step of performing the impregnation and calcination of additional binder pitch once or more to the calcined product to obtain an impregnation calcination product; the graphitization step of heating and graphitizing the impregnation calcination product at 2000°C or more to obtain a graphitization product; and the second impregnation calcination step of performing the impregnation and calcination of additional binder pitch once or more to the graphitization product.SELECTED DRAWING: Figure 1

Disclosed in the present application are a non-noble metal-based bifunctional catalyst, a preparation method therefor, and the use thereof. The non-noble metal-based bifunctional catalyst comprises a support and an active component; the support is a hydrogen-type ZSM-48 molecular sieve; the active component comprises an active element, the active element being selected from among at least one of Fe, Co and Ni, and the dispersion of the active component being 5.5-40%. The catalyst is prepared by preparing an aluminum source, a templating agent, an inorganic base, a metal precursor and water into a mother solution, and then adding the parent ZSM-48 molecular sieve to the mother solution to be subjected to hydrothermal crystallization at a certain temperature. An one-step recrystallization policy is used to simultaneously construct metal sites and acid sites of the bifunctional catalyst. The bifunctional catalyst prepared by the method has advantages of high metal dispersion and good stability, and exhibits excellent catalytic activity and target product yields in chain alkane isomerization reactions.

The invention discloses a treatment method of electroplating wastewater, and belongs to the technical field of electroplating wastewater treatment. The process comprises the following steps: electrically adjusting the pH value of the electroplating wastewater to 2.5-4.0, adding ferrite, adopting a Ti / PbO2 anode and a graphite cathode, controlling the current density to 15-30mA / cm, introducing air, reacting for 40-80 minutes, and adjusting the pH value to 6.0-7.0 after the reaction; introducing the wastewater into a chelating resin column, wherein the chelating resin is an amino phosphonic acid type or iminodiacetic acid type; the method comprises the following steps of: introducing into a built-in filter column, loading two layers of recrystallized silicon carbide honeycomb ceramic membranes in the filter column in parallel, performing cross-flow filtration under the conditions that the operation pressure is 0.8-2.0 MPa, the temperature is 25-40 DEG C and the cross-flow velocity is 1.5-3m / s, and collecting permeate; the permeate liquid is used for backwashing every 8-12 hours of operation. According to the method, heavy metal ions in the electroplating wastewater can be effectively removed, and the treatment efficiency of the electroplating wastewater is improved.

The invention discloses a ferrocene-based D-A type multi-system conjugated small molecule synthesis method, which comprises: carrying out a heating reaction in an organic solvent by using a ferrocenyl compound and a bromophenyl compound as raw materials and using a palladium complex as a catalyst, and after the reaction is completed, carrying out extraction, column chromatography and recrystallization to prepare an intermediate; the obtained intermediate and a 4-pyridine boric acid compound are used as raw materials, a palladium complex is used as a catalyst, a heating reaction is conducted in an organic solvent, and after the reaction is finished, cooling, extraction, column chromatography and recrystallization are conducted to prepare the D-A type multi-system conjugated small molecules. The invention also discloses a memory device with a sandwich structure and application of the memory device to ultra-high density information storage. The small molecular material prepared by the invention not only can realize ternary information storage performance, but also greatly improves the stability of the device through stable redox cycle of the ferrocene group, and realizes long-time stable ultrahigh-density information storage.

The invention discloses a purification method of high-purity tellurium, and belongs to the technical field of non-ferrous metallurgy. The method sequentially comprises the steps of raw material ultrasonic mechanical activation, ultrasonic selective recrystallization, smelting reduction refining, vacuum rectification purification and tellurium ingot forming, and volatile impurities such as selenium and sulfur are effectively removed by oxidizing calcination of a crude tellurium raw material; then, primary separation of impurities is realized in a manner of combining alkaline dissolution and oxidation precipitation, and then repeated purification is performed through low-temperature crystallization, so that the purity of tellurium is remarkably improved; metal impurities are further removed through smelting reduction treatment under the inert atmosphere, and preliminarily purified tellurium ingots are formed; step distillation separation is carried out by utilizing vapor pressure difference between tellurium and impurities under a high vacuum condition, and a pure tellurium component is enriched; and finally, melting in an inert atmosphere, cooling and forming to obtain the high-purity tellurium ingot. The method is stable in technological process, suitable for industrial application and capable of meeting the requirements of high-end fields such as semiconductors and photoelectric materials for high-purity tellurium materials.

The present invention discloses a silicon carbide crystal growth device, which relates to the technical field of silicon carbide crystal growth. A cylindrical filtering component is arranged in a crucible component, and an annular raw material cavity for placing silicon carbide raw materials is formed between the outer wall of the filtering component and the inner wall of the crucible component; in the present invention, the annular raw material cavity is arranged close to the inner wall of the crucible component, ensuring the temperature uniformity of the raw material area and avoiding recrystallization of the silicon carbide raw materials during mass transfer; moreover, the filtering component can block graphitized particles, reducing the generation of carbon inclusions; the material of the flow guiding ring is graphite, and a planar blocking area is formed on its lower surface. When the silicon-rich gas phase component contacts the lower surface of the flow guiding ring at the initial stage of silicon carbide crystal growth, the gas phase component SiC is generated by reaction, reducing the adverse effects brought by the silicon-rich atmosphere. The present invention also discloses a silicon carbide crystal growth method, which pre-treats the silicon carbide raw materials by means of heating-holding-cooling to improve the quality of the generated silicon carbide crystals.

The invention relates to an oil-water separation membrane as well as a preparation method and application thereof, and belongs to the field of gas field brine pretreatment. The oil-water separation membrane comprises a nanofiber membrane substrate and an MOFs layer loaded on at least part of the surface of the nanofiber membrane substrate, and the MOFs layer comprises two-dimensional MOFs nanosheets; the nanofiber membrane substrate is prepared by performing electrospinning on three-dimensional MOFs and an organic polymer; the two-dimensional MOFs nanosheet is obtained by secondary growth on the surface of the nanofiber membrane substrate through hydrothermal recrystallization. The oil-water separation membrane can be used for efficiently separating petroleum pollutants and solid suspended matters in the oil and gas field produced wastewater, and can be coupled with an advanced oxidation process based on sulfate free radicals to realize synchronous and efficient removal of oil, suspended particles and organic matters in the oil and gas field produced wastewater.

The invention relates to the technical field of food freezing, and discloses a composite refrigerating fluid for rapid steeping and freezing of beefsteak, and the core of the technical scheme is that the refrigerating fluid comprises the following components in percentage by weight: 20-30% of L-proline, 0.01-0.05% of nano silicon dioxide, 5-10% of sodium chloride, 5-10% of propylene glycol and the balance of water. The innovation mechanism of the invention lies in the synergistic effect of the four components: sodium chloride and propylene glycol construct an efficient heat transfer basis capable of maintaining a liquid state at a cryogenic temperature; the nano silicon dioxide is used as a uniformly dispersed ice nucleating agent, a large number of fine ice crystals are formed on the surface of the beef steak and in the refrigerating fluid through induction, and the macroscopic heat conduction efficiency is improved, so that quick freezing is realized; the core component L-proline is used as an efficient cryoprotectant, and is combined with water molecules to form a glassy network, so that growth and recrystallization of ice crystals in the freezing process are effectively inhibited, and the integrity of a muscle cell structure is protected.

The invention relates to a continuous production method of ultra-pure 2, 3, 4, 4 '-tetrahydroxybenzophenone, which comprises the following steps: completely dissolving p-hydroxybenzoic acid in high-boiling range petroleum ether, and completely dissolving pyrogallic acid in the high-boiling range petroleum ether; the preparation method comprises the following steps: adding a p-hydroxybenzoic acid solution and a pyrogallic acid solution into an ultra-pure continuous reactor group, adding boron trifluoride diethyl etherate into the ultra-pure continuous reactor group at a flowing speed, reacting at 110-140 DEG C, adding the obtained reaction solution into the next ultra-pure continuous reactor group, stirring in ice water, filtering, washing and recrystallizing to obtain the 2, 3, 4, 5-tetramethyl-3, 5-dihydroxybenzoic acid. According to the present invention, the reaction time is substantially shortened, the conversion rate is 70-80%, the purity of the obtained electronic product is more than or equal to 99.2%, the content of the metal ions such as sodium, aluminum, copper, iron, calcium, zinc and boron is less than or equal to 60 ppb, the reaction materials, the reaction temperature and the reaction rate are controllable, the reaction is sufficient, the yield of the obtained target product is stable, and the method can be used for continuous production.

The application belongs to the technical field of medicine synthesis and provides a preparation method of phosphonic acid levomoxiflazine disodium, which comprises the following steps: taking levomoxiflazine as raw material, performing esterification through phosphorus oxychloride and hydrolysis to obtain a reaction solution containing phosphonic acid levomoxiflazine; slowly and uniformly adding a sodium hydroxide methanol solution, first adjusting pH to 6.3-7.6, filtering out impurities, then adjusting pH to 9.1-9.8, crystallizing and drying to obtain a crude product; and performing recrystallization through a water-ethanol-acetone mixed system, filtering and drying to obtain a high-purity product. The application solves the problems of high impurity content and low yield in the prior art by optimizing the amount of esterification reagent, the pH adjustment mode and the recrystallization system, the HPLC purity of the obtained phosphonic acid levomoxiflazine disodium is greater than or equal to 99.97%, the maximum single impurity content is less than or equal to 0.02%, the process is simple, easy to operate, stable and suitable for industrial amplification production.

This invention relates to the field of hydrometallurgical technology and discloses a method for purifying and recovering ammonium perrylate using a combination of electrodialysis and ion exchange. The method first adjusts the pH of the rhenium-containing feed solution, then selectively enriches perrylate ions using electrodialysis to obtain a high-concentration rhenium-rich solution. Subsequently, the rhenium-rich solution is subjected to deep adsorption purification through an anion exchange column. Next, rhenium is eluted from the saturated resin using an eluent to obtain a pure ammonium perrylate solution. Finally, high-purity ammonium perrylate crystals are obtained through evaporation, concentration, cooling, crystallization, and drying. Optionally, the obtained crystals can be recrystallized to further improve purity. This invention ensures the purity and process stability of the rhenium-rich solution obtained in the pre-enrichment stage, improves the overall adsorption capacity, desorption rate, and reliability of the process operation of the resin, and guarantees the stability of the final ammonium perrylate product purity and the economic benefits of the entire process recovery.

The invention discloses a powdery emulsion explosive with eutectic inorganic salt as an internal phase and a preparation method, and relates to the technical field of powdery emulsion explosives, the powdery emulsion explosive comprises the following raw materials by weight: 90-110 parts of eutectic inorganic salt and 5-7 parts of a composite oil phase; wherein the eutectic inorganic salt is prepared by recrystallizing ammonium nitrate and sodium chloride. Ammonium nitrate and sodium chloride are combined in a recrystallization manner, so that sodium chloride is uniformly distributed in ammonium nitrate crystals in a lattice doping manner, a molecular-level dispersion effect is realized, and the flame inhibitor is more uniformly dispersed in an inner phase; secondly, the eutectic inorganic salt has a synergistic decomposition peak at 210-240 DEG C, and chloride ions are released in advance to interact with active groups generated by explosion; under the combined action of the two factors, sodium chloride is used as a flame inhibitor to play a role more effectively at the flame front, the flame temperature is reduced, and flame propagation is inhibited.

The impurity removal and crystallization device comprises a catalyst settling kettle, one side of the catalyst settling kettle is provided with a crude product feed port, the top of the catalyst settling kettle is provided with a hydrogen feed port, the bottom of the catalyst settling kettle is provided with a catalyst recovery discharge port, and the catalyst recovery discharge port is provided with an impurity removal and crystallization device. One side, far away from the crude product feeding hole, of the catalyst settling kettle is provided with a first purified liquid discharging hole, one end, far away from the catalyst settling kettle, of the first purified liquid discharging hole is communicated with a first membrane filtering kettle, and the outer wall of the first membrane filtering kettle is provided with a first solid isolate discharging hole; a second purified liquid discharge hole is formed in the outer wall of the first membrane filtration kettle. The utility model relates to the technical field of chemical product production, and solves the problems that in the prior art, when impurity removal and crystallization are carried out on a p-aminobenzene sulfonic acid crude product, the crude product is not effectively decolorized, so that the color of a recrystallized product is not pure enough, and the appearance quality and the market acceptability of the product are influenced.