138 results about "Small particle" patented technology

The invention relates to the technical field of refrigeration cycle, and discloses a dry filter of an air conditioner refrigeration cycle system, which comprises a shell, a liquid inlet at the front end of the shell and a liquid outlet at the tail end of the shell, and a front filter plate and a rear filter plate are respectively mounted in the hollow annular table in a sliding manner. The space of the front drying cavity is increased, so that when small particles generated by pulverization of a drying agent are led to the rear drying cavity, the drying agent in the rear drying cavity is kept in a compact state at the moment, and it is ensured that the rear drying cavity has the capacity of adsorbing moisture in a refrigerant; when the space of the rear drying cavity is increased, small particles generated by pulverization of the drying agent are discharged out of the drying cavity, at the moment, the drying agent in the front drying cavity is kept in a compact state, and it is ensured that the front drying cavity has the capacity of adsorbing moisture in the refrigerant. Therefore, small particles generated by pulverization of the drying agent can be effectively cleaned, and moisture in the refrigerant can be reliably removed.

The invention belongs to the technical field of crystal compound preparation, and particularly relates to a crystallization process of small-particle-size palmitic acid paliperidone. The invention discloses a small-particle-size palmitic acid paliperidone crystallization process, solves the problems of large particle size, non-uniform distribution and serious agglomeration of the existing process product, and meets the requirements of long-acting injection bulk drugs. The process comprises the following steps: adding paliperidone palmitate into a specific mixed organic solvent according to a solid-to-liquid ratio of 0.04-0.09 g / g, stirring, dissolving and filtering at 65-75 DEG C, transferring into a high-pressure closed crystallizer, and pressurizing to 1.0-1.5 MPa; cooling and decompressing in sections, stirring, filtering and washing, and drying in vacuum at the temperature of 40-50 DEG C and the vacuum degree of-0.1 MPa to obtain a finished product. According to the invention, the process parameters are accurately controlled, the product is an irregular short rod-like / granular crystal, the particle size is in a normal single peak, the Dv (90) is 7.866-9.514 microns, the HPLC (High Performance Liquid Chromatography) purity is greater than or equal to 99.92%, the yield is greater than or equal to 90.25%, micronization is not needed, the process is stable, the economical efficiency is good, and the industrial application value is realized.

The application discloses a filter core material and a preparation method thereof, and belongs to the technical field of water purification filter cores. The filter core material comprises the following components in percentage by mass: a honeycomb support matrix: 15-60%; a filter substrate: 30-40%; and a coating substrate: 0-50%. The filter core material and the preparation method thereof maintain a stable support structure during the preparation of a gamma-Al2O3 / BN composite ceramic layer through polypropylene and cellulose nanofiber. The filter substrate is obtained through gradient low-temperature sintering, effectively removes small particles and pollutants in water, and has excellent filtering performance. The active carbon fiber and polyether sulfone are coated on the filter substrate through electrospinning, which ensures good filtering performance and water permeability, improves the wear resistance and compressive strength of the filter core, and removes the honeycomb support matrix through high-temperature combustion, further improves the water permeability, and the active carbon fiber is physically activated during the combustion process, further improving the adsorption capacity.

The present application relates to a kind of high-efficiency lossless preparation multi-element wafer assembly method, the method utilizes the high bonding strength of water boiling glue epoxy adhesive, excellent water boiling glue, glue layer soft characteristics, so that piezoelectric ceramic small particle does not fall in wafer assembly preparation process, substrate removal is simple and easy, and does not damage the electrode surface of piezoelectric ceramic small column, including the following steps: surface treatment;Gluing;Cutting;Washing, normal temperature air dry;Low-temperature prebaking, fill high molecular decoupling material, remove the decoupling material on the electrode surface of piezoelectric ceramic small particle clean;Solidification;Polish and remove substrate;Remove excess particles to form approximately circular wafer assembly;Positive and negative electrode line lead out.The present application prepares multi-element wafer assembly method, utilizes the high bonding strength of water boiling glue epoxy adhesive, good impact resistance characteristics, overcomes the problem that its bonding strength is reduced due to factors such as water vapor and temperature in preparation process, and does not damage the electrode surface of piezoelectric ceramic small column.

The utility model belongs to the technical field of polyvinyl chloride discharging, and particularly discloses polyvinyl chloride particle quantitative discharging equipment which comprises a discharging hopper, a bottom frame is arranged below the discharging hopper, a material collecting frame is movably arranged at the top end in the bottom frame, and a material collecting bin is formed in the top of the material collecting frame. A waste bin is formed in the material collecting frame, a driving mechanism is arranged at the front end of the bottom of the material collecting frame and matched with the material collecting frame, a connecting mechanism is arranged in the opening, and a guide column is arranged in the discharging hopper. By changing the heights of the two ends of the material receiving frame, quantitative discharging operation of materials is completed, meanwhile, the materials can be dispersed and layered in the material receiving bin, and fine particles, impurities and the like in the materials are filtered in a vibrating mode.

This utility model belongs to the field of semiconductor manufacturing technology and discloses a wafer basket handle, including a top plate; two handles, which are arranged opposite each other and connected to the top center of the top plate; four stepped grooves, with every two stepped grooves symmetrically arranged at the bottom of the handle; and four cushioning pads, each cushioning pad being embedded in the corresponding stepped groove. This utility model, by providing a mounting groove at the top center of the top plate, allows the two handles to rotate within the mounting groove via cotter pins. The two corners of the handle's grip end are press-fitted with urethane rubber cushioning pads with a Shore A hardness, which can replace the hard contact between the handle and the top plate, thereby reducing impact force, high-frequency vibration, and the generation of fine particles.

The invention belongs to the technical field of lithium ion battery positive electrode materials, and provides a small-particle precursor for a manganese-rich positive electrode material and a preparation method of the small-particle precursor. The manganese-rich precursor with fine primary particles and large specific surface area is prepared by using the non-ammonia complexing agent, an oxidizing atmosphere is not needed, the preparation process is simple, the process control is stable, and mass production conversion is facilitated.

The invention discloses a bubble generating mechanism, a micro-nano bubble host comprising the bubble generating mechanism and application of the bubble generating mechanism in the processing technology of photovoltaic cells. The bubble generating mechanism comprises an outer shell and an inner shell which are sleeved with each other, a liquid flow channel allowing liquid to flow through is formed in the middle of the inner shell and comprises a first flow channel, a throat part and a second flow channel, and the end, close to the second end, of the first flow channel is connected with the throat part; the inner diameter of the throat portion does not exceed the inner diameter of the end, close to the second end, of the first flow channel, the inner diameter of the second flow channel is gradually increased in the direction close to the second end, the inner surface of the second flow channel is a smooth wall face, the air inlet flow channel communicates with the liquid flow channel in the circumferential direction, and the air inlet flow channel communicates with the throat portion in the circumferential direction. And the inner surface of at least partial area of the first flow channel is a spiral flow channel. The bubble generating mechanism can ensure that the generated micro-nano bubbles are smaller in particle size and more stable.

The utility model belongs to the technical field of evaporative crystallization equipment, and relates to a high-temperature crystallization tower which comprises a crystallization tower main body, a crystallization pipe, a solution spraying area and a material screening device, a crystallization pipe, a solution spraying area, a material screening device and a mixing and returning area are sequentially arranged in the crystallization tower main body from top to bottom, the mixing and returning area is communicated with the solution spraying area, and a discharging opening of the material screening device abuts against the material plate vibration piece. According to the utility model, through the multilayer arrangement of the crystallization pipes and the vertical layered layout of the solution spraying area, the staged temperature control in the decomposition reaction process is realized, and the generation of tiny crystal nucleuses is reduced through atomization crystallization; the material screening device is matched with the material plate vibration piece, crystallization products can be dynamically screened, fine particles which do not reach the standard participate in crystallization circulation again through the mixing and returning area, and the crystallization integrity is improved.

The invention discloses an anti-blocking multistage division coal sampling machine, and relates to the anti-blocking field of coal sample preparation, the anti-blocking multistage division coal sampling machine comprises a sample preparation unit, the sample preparation unit is provided with a feed inlet, a crushing cavity and a discharge end; a first filter plate is arranged at the end, away from the feeding port, of the crushing cavity, and an anti-blocking unit is arranged on the side, away from the feeding port, of the first filter plate. The anti-blocking unit comprises a rotating assembly arranged on a crushing shaft of the sampling machine and a driven assembly corresponding to the rotating assembly; the driven assembly does linear reciprocating motion along with rotation of the rotating assembly, and bristles are arranged on the surface of the side, close to the filter plate, of the driven assembly. According to the coal sampling machine, the driven assembly is driven by the rotating assembly to reciprocate, so that the driven assembly continuously scrapes the filter plate along with the work of the coal sampling machine, and the scraping of the filter plate by the driven assembly is reflected in the transverse direction and the longitudinal direction, so that small-particle coal samples are helped to pass through the filter plate under the action of the bristles, and the coal samples are prevented from being agglomerated and adhered.

The utility model discloses a screening device for straw recovery, which belongs to the technical field of straw recovery and comprises a screening box, a screening cylinder is arranged in the screening box, a feeding port matched with the input end of the screening cylinder is arranged on one side of the screening box, the screening cylinder is inclined, the screen mesh of the screening cylinder has various apertures, and the screening cylinder is provided with a feeding port matched with the input end of the screening cylinder. A first blanking port and a second blanking port are formed in the lower end of the screening box, a connecting assembly used for being connected with the screening barrel is arranged in the feeding port, and an adjusting assembly used for driving the screening barrel to rotate and adjusting the aperture of the screen is arranged on the other side of the screening box. The straw screening device has the advantages that the screening barrel, the moving plate, the rotating shaft, the supporting rod, the connecting plate and the vibration motor are arranged, so that the screening barrel conducts vibration screening on materials, large-particle materials are discharged out of the first discharging port, small-particle materials are discharged out of the second discharging port, impurities and substances with different particle sizes in straw are efficiently separated, and the screening effect is good. And the purity and the treatment efficiency of straw recovery are improved.

The invention discloses a buccal product and a preparation method thereof. The buccal product comprises a buccal composition, wherein the buccal composition comprises an active component, a filling agent, a flavoring stimulant and water; wherein the flavoring stimulants comprise a first flavoring stimulant and a second flavoring stimulant, the particle size of the first flavoring stimulant is smaller than or equal to 100 microns, and the particle size of the second flavoring stimulant is 300-1000 microns. According to the buccal product disclosed by the invention, the local stimulation of the buccal product is superposed with the continuous stimulation of the first taste-modifying stimulant with the smaller particle size by utilizing the pricking point feeling formed when the second taste-modifying stimulant with the larger particle size is locally contacted and dissolved in the oral cavity, so that the experience feeling of the buccal product is enhanced.

To accurately detect fine particles without complicating a device configuration.SOLUTION: The condensation particle counter includes a supply unit configured to supply a working fluid to a periphery of an inlet of a condensation tube through which an aerosol containing sample particles flows, a saturation unit configured to saturate the aerosol with vapor of the working fluid, and a control unit configured to condense and grow the aerosol into droplets using the sample particles as nuclei and extract the aerosol containing the droplets from a center axis of a condensation-growth tube connected to the condensation tube. A condensation and growth section that and exhausts excess working fluid that has flowed down an inner wall of a condensation and growth tube, vapor of the working fluid that has condensed on the inner wall, and water vapor together with excess aerosol, a flow rate control section that controls a flow rate of the aerosol flowing through a capillary tube that the aerosol containing droplets after condensation and growth at a minute flow rate, a double cylindrical sheath flow that positions the aerosol that has passed through the capillary tube on an extension line of a central axis of the capillary tube, and a droplet counting section that counts the droplets contained in the aerosol based on the droplets flowing through the capillary tube, wherein the working fluid contains an alkane having a carbon number of 14 or less.SELECTED DRAWING: Figure 1

This invention relates to the field of rare earth oxide technology and provides a method for preparing rare earth oxide powder. The invention uses oxalic acid as a precipitant and employs an airflow precipitation reactor to carry out a precipitation reaction, obtaining a rare earth oxalate precursor. The oxalate precursor is then calcined to obtain rare earth oxide powder. This invention uses an airflow precipitation reactor to carry out the precipitation reaction, utilizing the disturbance effect of gas on the liquid to promote the exchange and mixing of substances during the precipitation reaction, making the precipitation reaction more uniform and complete, thereby obtaining a rare earth oxalate precursor with a smaller particle size. Calcination then yields rare earth oxide powder with a large specific surface area. Example results show that the specific surface area of ​​the rare earth oxide powder prepared by this invention reaches 20.586~52.499 m². 2 / g, and the particle size is uniform.

The utility model discloses a fracturing flow-back fluid multistage cyclone desanding device which comprises a processing support, a plurality of filter tanks are arranged on the processing support, the filter tanks are installed on the processing support in a step shape, filter rollers are arranged on the inner sides of the filter tanks, a pair of inclined blocks are arranged on the filter tanks, and the inclined blocks are arranged on the inner sides of the filter tanks. The utility model relates to the technical field of flowback fluid treatment, adopts the multi-stage filtering design, adopts the plurality of filtering basins which are installed in a step shape, and is matched with the filtering drum, the filtering nets and the filtering plates on the U-shaped inclined blocks, so that the flowback fluid can be effectively filtered, and the flowback fluid can be efficiently and efficiently treated by the filtering drum, the filtering nets and the filtering plates on the U-shaped inclined blocks and the like. According to the flow-back liquid filter, graded fine filtration can be carried out according to the characteristics of impurities with different particle sizes in flow-back liquid, the filtration precision is greatly improved, various solid substances, fine particles and suspended solids are effectively removed, and it is ensured that the treated liquid meets the high-standard recycling or discharging requirement.

1. Name of the product in this design: Divider Wheel Unloader (L0208). 2. Purpose of this design: For quantitative feeding of powder or small granular materials. 3. The key design feature of this product is its shape. 4. The image or photograph that best illustrates the design's key points: a 3D model. 5. The rear view is symmetrical to the front view, so the rear view is omitted.

The utility model relates to the technical field of water reducing agent production, and discloses a powder filtering and grinding device for water reducing agent processing, which comprises a grinding cylinder, a first motor is mounted at the left end of the grinding cylinder through a foot stool, a crushing box is mounted at the top of the grinding cylinder through a foot stool, and crushing teeth are inserted into two sides of an inner cavity of the crushing box through rotating shafts; the gear is coaxially connected to the left ends of the crushing teeth, a second motor is installed on the left side of the outer portion of the crushing box through a foot stool, and the rotor assembling end of the first motor is coaxially connected with a rotating shaft; and the supports are circumferentially connected to the two sides of the outer portion of the rotating shaft, and grinding wheels are arranged on the inner sides of the supports. According to the powder filtering and grinding device for processing the water reducing agent, a second motor drives a gear to rotate, so that two groups of crushing teeth can rotate to crush a powder material in advance to enable the powder material to become smaller particles, and then the speed of a subsequent grinding process can be increased.

The present invention provides an aqueous liquid composition for use in coating plastic substrates, which exhibits excellent storage stability, reduced powdering, adhesion, moisture resistance, blocking resistance, and plate cleaning properties. [Solution] An aqueous liquid composition for use in coating plastic substrates, comprising: an aqueous binder resin (A) selected from the group consisting of aqueous urethane resin, aqueous acrylic resin, and aqueous acrylic urethane resin; a large particle size wax (B); a small particle size wax (C); and a resin (D) having a polymerization chain including a hydrophobic portion and a hydrophilic portion including an acid group, wherein the large particle size wax (B) has an average particle size of 2.0 μm or more and 10.0 μm or less, and a penetration degree of 5 or more and 30 or less; the small particle size wax (C) has an average particle size of 0.1 μm or more and less than 2.0 μm, and a penetration degree of 0.1 or more and less than 15; and the solid content of resin (D) relative to the total mass of solid content of the aqueous liquid composition is 0.1 to 10% by mass.

The invention provides a method for preparing a low-segregation Cu-Ta alloy by using Ta2O5, and belongs to the technical field of copper alloy material preparation. The preparation method comprises the following steps: performing mechanical alloying on Cu powder and Ta2O5 powder to prepare precursor powder, performing magnesiothermic reduction reaction on the precursor powder, Mg powder and KCl powder, performing acid pickling and water washing to obtain Cu-Ta mixed powder, and finally performing reduction and spark plasma sintering to obtain the Cu-Ta composite material. In the ball milling process, Ta2O5 can serve as a process control agent to inhibit growth of copper grains, the particle size of the powder obtained after ball milling is kept at the micron level, and the powder with the small particle size is easier to sinter and compact. Compared with a method for preparing Cu-Ta composite powder by using Ta powder, the method has the advantages that Ta2O5 is in a crystalline state, is high in brittleness and easy to crush, and is better in dispersity when being subjected to ball milling with Cu powder, dispersed phase particles obtained after ball milling are finer and more uniform in dispersion, and the finally prepared Cu-Ta alloy has better conductivity and mechanical property.

The present application belongs to the technical field of waste gas purification, and discloses a heat treatment waste gas treatment device, which comprises an industrial carburizing furnace and a centrifugal pipe. A convex cap is fixed between the top of the centrifugal pipe. A fixing sleeve is fixed to the inner top surface of the convex cap. The bottom of the fixing sleeve extends downward to the inside of the centrifugal pipe. An air inlet pipe is connected to the side of the centrifugal pipe close to the top edge. When the waste gas is introduced into the centrifugal pipe for separation, the air delivered to the inside of the centrifugal pipe is driven to rotate by a centrifugal driving device. Under the action of centrifugal force, the fine particulate matter suspended in the air is collected to the middle of the bottom of the centrifugal pipe. The fine particles can fall into the neutralizing solution in the inside of the conical disc. As the fine particles are absorbed by the neutralizing solution, the weight of the conical disc as a whole is increased, so that it slides downward to trigger the traction device to drive the switching assembly to switch the flow direction of the air flow through the filter cartridge, so that the filter cartridge can be cleaned.

The invention belongs to the field of pharmaceutics, and particularly relates to a composition containing budesonide and formoterol, and the composition provided by the invention is in a specific pH range, adopts a specific surfactant addition mode, also adopts moist heat sterilization, and is free of toxic and side effects. The prepared inhalation suspension of formoterol and budesonide has better delivery rate and total delivery amount, better fine particle fraction and smaller particle size distribution, has the advantages of low temperature, short time, strong penetrating power, economy, rapidness and the like compared with dry heat sterilization and moist heat sterilization, and is more suitable for industrial mass production.

This invention discloses an anti-ultraviolet pesticide formulation with small particle size, uniform distribution, good stability, and excellent anti-ultraviolet function. It can effectively reduce the ultraviolet photolysis of abamectin, which is conducive to prolonging the effective period of the formulation and reducing the overall amount of pesticide used. This conforms to the green control policy of increasing the efficacy and reducing the amount of pesticides used, and provides a new option for the scientific and reduced use of pesticides.

The purification of monoalkyl tin trialkoxides and monoalkyl tin triamides are described using fractional distillation and / or ultrafiltration. The purified compositions are useful as radiation sensitive patterning compositions or precursors thereof. The fractional distillation process has been found to be effective for the removal of metal impurities down to very low levels. The ultrafiltration processes have been found to be effective at removal of fine particulates. Commercially practical processing techniques are described.

The invention discloses a fluorescently-labeled PVA (polyvinyl alcohol) micro-nano plastic which can be used for labeling micro-nano plastic with small particle size and is stable in fluorescence signal as well as a preparation method and application of the fluorescently-labeled PVA micro-nano plastic. The preparation method of the fluorescence-labeled PVA micro-nano plastic comprises the following steps: step (1), dissolving PVA and 4-carboxyphenylboronic acid in a good solvent, adding lanthanide metal salt, and performing constant-temperature heating reaction to obtain a precursor solution; and (2) injecting a diluent of the precursor solution into an anti-solvent in a heating and stirring state, cooling to room temperature after injection is finished, and after precipitation is generated, centrifuging, washing and drying to obtain the fluorescence-labeled PVA micro-nano plastic.

The invention relates to the field of tea granulation, and provides a circular tea granulation process based on a pneumatic dry method, which comprises the following steps of: preparing raw materials, removing impurities, deactivating enzymes, drying, screening, removing foreign matters, mixing, treating by a dry granulator, circularly reproducing fine powder and small particles, conveying finished product particles, screening out the fine powder and the particles, grinding, circularly reproducing after grinding, and finally discharging the finished product particles. The dry type granulator comprises a machine body, a discharging pipe is arranged at a discharging port in the bottom of the machine body, a vertical cylinder is fixedly installed on one side of the machine body, a collecting box is fixedly installed at the bottom of the vertical cylinder, the bottom of the vertical cylinder is communicated with the top of the collecting box, a conveying pipe is fixedly installed at the top of the collecting box, and a discharging pipe is arranged on the top side of the conveying pipe. Through pneumatic dry granulation, fine powder, small particles and unformed particles generated in the finished product particle processing process can be effectively and circularly remanufactured, raw materials are saved, and meanwhile the quality of finished product particles can be prevented from being affected.

The utility model discloses a double-channel large-scale sorting vibrating screen, relates to the technical field of sorting vibrating screen equipment, and aims to solve the problems that the efficiency is not high due to the fact that an existing large-scale vibrating screen is difficult to realize automatic balanced distribution of multi-channel materials, and the separation is not thorough due to the fact that part of fine particles are easy to adhere to larger particles after screening. Two groups of screens are arranged in the screen box to divide the screen box into an upper-layer channel, a lower-layer channel and a finished product channel; an automatic material distributing assembly composed of a material distributing plate, a balancing weight, a torsion spring and the like is arranged at the feeding end and used for automatically adjusting materials to enter the upper layer channel and the lower layer channel according to the feeding condition. A first filtering hole and a second filtering hole which are the same as the screen in aperture are formed in the upper-layer discharging channel and the lower-layer discharging channel of the discharging end, balanced distribution of materials is achieved through the automatic material distributing assembly, and the screening efficiency and the equipment processing capacity are improved; and the oversize materials are secondarily filtered through the filtering holes in the discharging channel, so that the purity of the finally sorted materials is improved, and more thorough separation is realized.

The invention relates to stress whitening resistant polypropylene, and belongs to the technical field of high polymer materials. The talcum powder with different particle sizes is respectively modified, and the large-particle-size talcum powder is modified by 2, 5-di-tert-butylphenylurea siloxane, so that the nucleation capability of the large-particle-size talcum powder on polypropylene is improved, and the polypropylene is more perfect in crystal lattice, fewer in defect and better in stress whitening resistance; maleic anhydride grafted ethylene-octylene copolymer modification is carried out on the small-particle-size talcum powder, the heterogeneous nucleation effect of the talcum powder is improved, and the talcum powder and polypropylene can form a good phase interface, so that crystal lattices of the polypropylene are more perfect, defects are fewer, and the stress whitening resistance is better.

The invention relates to the technical field of lithium ion batteries, and discloses a ternary positive electrode material and a preparation method and application thereof. The preparation method of the ternary positive electrode material provided by the invention comprises the following steps: S1, mixing a small-particle ternary positive electrode material precursor with a lithium source and a doping agent, carrying out first sintering, cooling and crushing to obtain a small-particle primary sintering product; mixing the large-particle ternary positive electrode material precursor with a lithium source and a doping agent, carrying out primary sintering, and crushing to obtain a large-particle primary sintering product; and S2, mixing the small-particle primary sintering product and the large-particle primary sintering product with a coating agent, and carrying out secondary sintering to obtain the ternary positive electrode material. The ternary positive electrode material prepared by the preparation method provided by the invention is large in compaction density, low in residual alkali content, good in interface stability, and relatively good in capacity and cycling stability, and the electrochemical performance of the ternary positive electrode material under a high-voltage condition is remarkably improved.

The present invention relates to a method for dry sorting waste batteries, the method comprising: a step for preparing a raw material valuable metal product (VM) by performing a high-temperature reduction reaction on crushed waste batteries; a classification step for primarily crushing the raw material valuable metal product and then separating same by particle size; and a step for secondarily crushing and then air-classifying the valuable metal product separated by particle size in the classification step, wherein a large-diameter valuable metal product (LM) having a particle size of 100 ㎛ or more and a small-diameter valuable metal product (SM) having a particle size of less than 100 ㎛ may be separated in the classification step.

This invention provides a method for preparing large-particle lithium fluoride crystals, relating to the field of chemical engineering crystallization technology, aiming to solve the problem of small particle size in existing lithium fluoride crystals. The key technical points are: first, lithium fluoride seed crystals are added to pure water to obtain a lithium fluoride crystal slurry; then, the lithium fluoride crystal slurry is placed in a crystallization vessel, stirring is started, and lithium hydroxide aqueous solution and hydrofluoric acid aqueous solution are simultaneously and uniformly added dropwise; after the addition is complete, the crystal slurry is filtered to obtain a filter cake, the filter cake is washed with deionized water, and the filter cake is dried to obtain D. 50 The lithium fluoride seed crystals are large-particle lithium fluoride crystals with a size of 170-190 μm; the D of the lithium fluoride seed crystals... 50 The particle size is 2-50 μm, and the dropping time is 5-48 h. This invention balances the generation and consumption of supersaturation by precisely controlling the reaction system and dropping method, inhibiting nucleation and promoting crystal growth, and is suitable for the preparation of large-particle lithium fluoride.