Preparation method of micro-particle-size zinc sulfide

Abstract

The invention relates to the technical field of zinc sulfide preparation, in particular to a micro-particle-size zinc sulfide preparation method which comprises the steps that zinc oxide powder is dispersed in O / W type microemulsion, sulfuric acid is dropwise added for reaction, and zinc sulfate microemulsion is obtained; introducing hydrogen sulfide gas into the zinc sulfate microemulsion, maintaining the reaction temperature of 25 DEG C, and continuously stirring to obtain a reaction suspension; transferring the reaction suspension to centrifugal equipment, collecting bottom precipitate, washing and drying to obtain a zinc sulfide primary product; dispersing the zinc sulfide primary product in the coating liquid, continuously stirring, then transferring into a vacuum drying oven for drying to obtain micro-particle-size zinc sulfide powder, and finally barreling by filling equipment, scanning and warehousing to obtain a finished product. The O / W type microemulsion limits the reaction in a water core through the confinement effect, the particle size of zinc sulfide is directly locked in a range equivalent to the size of the water core, and the problem that the particle size is too large due to free growth of crystals in a conventional solution reaction is fundamentally avoided.

Description

Technical Field

[0001] This invention relates to the field of zinc sulfide preparation technology, specifically a method for preparing zinc sulfide with a particle size. Background Technology

[0002] Zinc sulfide, as an important inorganic compound, has shown broad application prospects in many fields such as photocatalysis, sensors, and infrared optical devices due to its unique physicochemical properties, such as high infrared transmittance, excellent photoluminescence performance, and wide bandgap semiconductor characteristics.

[0003] Chinese invention patent CN112110479A discloses a method for preparing zinc sulfide, comprising the following steps: Step S1, providing zinc sulfate crystals and placing them in a reaction vessel; Step S2, continuously introducing hydrogen gas into the reaction vessel and performing gradient calcination to carry out the reaction, cooling after the reaction is completed to obtain a zinc sulfide precursor; Step S3, processing the zinc sulfide precursor obtained in Step S2. However, the above method has significant limitations in practical applications.

[0004] First, safety risks are significant. Hydrogen is a typical flammable and explosive gas; if the reaction vessel is not properly sealed, an explosion can easily occur during calcination. In large-scale production, the storage, transportation, and exhaust gas treatment of hydrogen all require strict explosion-proof measures, significantly increasing safety management costs, and uncontrollable risks still exist. Second, energy costs remain high. The reaction between zinc sulfate and hydrogen is an endothermic reaction, and the calcination temperature typically needs to reach 500℃. Maintaining this high temperature for a prolonged period consumes a large amount of energy, resulting in significantly high energy consumption per unit of product. Third, the product particle size is difficult to control precisely, making it difficult to meet the application requirements of zinc sulfide with fine particle size. Summary of the Invention

[0005] In view of the above-mentioned problems in the existing technology, the purpose of the present invention is to provide a method for preparing zinc sulfide with high particle size, so as to solve the technical defects of the existing methods, such as high safety risk, high energy consumption, high equipment cost and difficulty in accurately controlling the particle size of the product.

[0006] Specifically, a method for preparing zinc sulfide with a particle size includes the following steps: 1) Disperse 60-100 parts of zinc oxide powder in 230 parts of O / W type microemulsion by mass, add sulfuric acid of 30% by mass at 4 times the mass of zinc oxide powder, and stir continuously to obtain zinc sulfate microemulsion; 2) Hydrogen sulfide gas was introduced into the zinc sulfate microemulsion at a flow rate of 200 mL / min, the reaction temperature was maintained at 25 °C, and the mixture was stirred continuously to obtain a reaction suspension. 3) Transfer the reaction suspension to a centrifuge, collect the bottom precipitate, wash and dry it to obtain zinc sulfide primary product; 4) Add oleic acid to anhydrous ethanol and stir to obtain a coating solution with a mass concentration of 5% to 8%; 5) Disperse the zinc sulfide primary product in the coating liquid at a solid-liquid ratio of 1:10, stir continuously, and then transfer it to a vacuum drying oven for drying to obtain zinc sulfide powder with fine particle size. Finally, fill it into barrels and scan it into the warehouse to obtain the finished product.

[0007] Preferably, the O / W microemulsion is formulated from surfactant, mixed oil phase, co-surfactant and deionized water in a mass ratio of 1.8-2.2:5-6.5:0.8-1.2:28-32.

[0008] Preferably, the mixed oil phase is composed of liquid paraffin and cyclohexane in a mass ratio of 2:1.

[0009] Preferably, the co-surfactant is n-hexanol.

[0010] Preferably, the surfactant is a mixture of Tween80 and Span80 in a mass ratio of 3:1.

[0011] Preferably, the particle size of the zinc oxide powder is ≤5μm.

[0012] After adopting the above technical solution, the beneficial effects of the present invention are: O / W microemulsions confine the reaction within the water core through a confinement effect, directly locking the zinc sulfide particle size within a range comparable to the water core size, thus fundamentally avoiding the problem of excessively large particle size caused by free crystal growth in conventional solution reactions.

[0013] Zinc sulfide powder with fine particle size can be stably metered and packaged in batches using a dedicated filling device, avoiding powder loss or contamination caused by manual operation. The rotating container assembly drives the container to rotate before filling, while a barcode scanner identifies container information in real time, ensuring that the filling information matches the product information. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a front view of the filling equipment; Figure 2 A 3D view of the filling equipment; Figure 3 This is a schematic diagram of the turntable assembly. Figure 4This is a schematic diagram of the weighing component.

[0016] In the diagram: 1-Frame, 2-Conveyor, 3-Platform, 4-Motor drive assembly, 5-Discharge port, 6-Auger conveyor assembly, 7-Hopper, 8-Turntable assembly, 9-Drive motor, 10-Turntable assembly, 11-Code scanner, 12-Agitator, 13-Enclosure, 14-Ring support, 15-Indexing turntable, 16-Mold cavity, 17-Weighing assembly, 18-First transmission pulley, 19-Second transmission pulley, 20-Servo motor, 21-Guide section, 22-Upright frame, 23-Rotary cylinder, 24-Baffle, 25-Rubber wheel, 26-Roller, 27-Pallet, 28-Weighing sensor. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Those skilled in the art will recognize that the invention can be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the invention by illustrating examples of it.

[0018] Example 1 This embodiment provides a method for preparing zinc sulfide with a particle size of 100 μm. The following are the specific preparation steps and technical details of this method.

[0019] Preparation of S1, O / W type microemulsion Maintain a 30°C water bath and stir at 300 rpm. Weigh out surfactant, mixed oil phase, co-surfactant, and deionized water according to a mass ratio of 1.8:5:0.8:28. After mixing, continue stirring for 30 min to obtain an O / W microemulsion with a total mass of 230 parts (parts by mass, the same below).

[0020] The mixed oil phase is composed of liquid paraffin and cyclohexane in a mass ratio of 2:1, the co-surfactant is n-hexanol, and the surfactant is a combination of Tween80 and Span80 in a mass ratio of 3:1.

[0021] The role of O / W type microemulsion is to construct a micro-reaction cavity of oil core-water continuous phase, thereby limiting the subsequent growth of zinc sulfide particles.

[0022] S2, Preparation of Zinc Sulfate Microemulsion Mechanical stirring (300 r / min) and ultrasonic dispersion (500 W, 25 kHz) were started and maintained at 30°C. 60 portions of zinc oxide powder with a particle size ≤ 5 μm were dispersed in the water core of an O / W microemulsion. 30% sulfuric acid was added dropwise at a rate of 6 mL / min, at a ratio of 4 times the mass of the zinc oxide powder. After the addition was complete, the reaction was continued for 15 min to obtain a zinc sulfate microemulsion.

[0023] S3, Preparation of zinc sulfide suspension by reaction of hydrogen sulfide gas. Hydrogen sulfide gas was introduced into the zinc sulfate microemulsion at a flow rate of 200 mL / min through a porous gas distributor at the bottom of the reaction chamber. The stirring speed was adjusted to 600 r / min, the reaction temperature was maintained at 25°C, and stirring was continued for 30 min. Then, the gas supply was stopped and the reaction was maintained for 10 min to obtain a reaction suspension.

[0024] S4. Separation and purification of zinc sulfide primary product Centrifuge at 8000 r / min for 15 min and collect the white precipitate at the bottom. Wash three times with deionized water at 80℃, collect the white precipitate again, and dry it in a vacuum drying oven at 60℃ for 2 h to obtain the initial zinc sulfide product.

[0025] S5, Oleic Acid Coating and Finished Product Preparation Oleic acid was added to anhydrous ethanol and stirred to obtain a coating solution with a mass concentration of 5%. Zinc sulfide precursor was dispersed in the coating solution at a solid-liquid mass ratio of 1:10, stirred at 300 rpm for 15 minutes, and then transferred to a vacuum drying oven at 60°C for 2 hours. Subsequently, airflow depolymerization was performed to obtain zinc sulfide powder with a particle size of 1.56 μm. Finally, the powder was filled into containers, scanned, and stored to obtain the finished zinc sulfide product with an average particle size of 1.56 μm.

[0026] Oleic acid coating can isolate zinc sulfide from moisture and oxygen in the air, preventing agglomeration or oxidation during subsequent filling, storage, and transportation. It can also be removed by calcination during application, ensuring the purity of zinc sulfide.

[0027] Example 2 Based on Example 1, with the method flow unchanged, only the quantity of materials is changed. The specific steps are as follows: 1) Weigh out the surfactant, mixed oil phase, co-surfactant, and deionized water according to the mass ratio of 2:5.5:1:30, mix them, and continue stirring for 30 minutes to obtain an O / W type microemulsion. 2) Disperse 80 parts of zinc oxide powder in 230 parts of O / W type microemulsion by mass, add sulfuric acid with a mass fraction of 30% at 4 times the mass of zinc oxide powder, and stir continuously to obtain zinc sulfate microemulsion; 3) Hydrogen sulfide gas was introduced into the zinc sulfate microemulsion at a flow rate of 200 mL / min, the reaction temperature was maintained at 25 °C, and the mixture was stirred continuously to obtain a reaction suspension. 4) Transfer the reaction suspension to a centrifuge, collect the bottom precipitate, wash and dry it to obtain zinc sulfide primary product; 5) Add oleic acid to anhydrous ethanol and stir to obtain a coating solution with a mass concentration of 6%; 6) Disperse the zinc sulfide primary product in the coating liquid at a solid-liquid ratio of 1:10, stir continuously, and then transfer it to a vacuum drying oven for drying to obtain zinc sulfide powder with a particle size. Finally, fill the powder into barrels using a filling equipment, scan it into the warehouse, and obtain the finished zinc sulfide product with an average particle size of 1.28μm.

[0028] Example 3 Based on Example 1, with the method flow unchanged, only the quantity of materials is changed. The specific steps are as follows: 1) Weigh out the surfactant, mixed oil phase, co-surfactant, and deionized water according to the mass ratio of 2.2∶6.5∶1.2∶32, mix them, and continue stirring for 30 min to obtain an O / W type microemulsion; 2) Disperse 100 parts of zinc oxide powder in 230 parts of O / W type microemulsion by mass, add sulfuric acid with a mass fraction of 30% dropwise at 4 times the mass of zinc oxide powder, and stir continuously to obtain zinc sulfate microemulsion. 3) Hydrogen sulfide gas was introduced into the zinc sulfate microemulsion at a flow rate of 200 mL / min, the reaction temperature was maintained at 25 °C, and the mixture was stirred continuously to obtain a reaction suspension. 4) Transfer the reaction suspension to a centrifuge, collect the bottom precipitate, wash and dry it to obtain zinc sulfide primary product; 5) Add oleic acid to anhydrous ethanol and stir to obtain a coating solution with a mass concentration of 8%; 6) Disperse the zinc sulfide primary product in the coating liquid at a solid-liquid ratio of 1:10, stir continuously, and then transfer it to a vacuum drying oven for drying to obtain zinc sulfide powder with a particle size. Finally, fill the powder into barrels using a filling equipment, scan it into the warehouse, and obtain the finished zinc sulfide product with an average particle size of 1.78μm.

[0029] Comparative Example 1 Based on Example 1, the steps related to the O / W type microemulsion were removed, and zinc oxide powder was allowed to react directly with sulfuric acid to obtain zinc sulfide product with an average particle size of 6.31 μm.

[0030] The present invention also provides an apparatus for preparing zinc sulfide with microparticle size, which can achieve stable metering and batch packaging of zinc sulfide with microparticle size, and avoid powder loss or contamination caused by manual operation.

[0031] like Figure 1 and Figure 3As shown, this filling equipment includes a frame 1. A platform 3 is mounted on the frame 1, and a turntable assembly 8 is installed on the platform 3. Through indexing positioning, real-time weighing, and container limiting, the filling accuracy and consistency of each batch of zinc sulfide powder are ensured. A conveyor 2 is installed on one side of the platform 3 to connect to the turntable assembly 8. A barrier assembly is provided on one side of the conveyor 2 to isolate and guide the containers to be filled into the turntable assembly 8 in batches.

[0032] like Figure 2 As shown, a hopper 7 is mounted on top of the frame 1, and an auger conveyor assembly 6 is installed at the bottom of the hopper 7. One end of the auger conveyor assembly 6 has a corresponding material discharge port 5 for the turntable assembly 8. An agitator 12 is installed inside the hopper 7, and a drive motor 9 is fixed to one side of the hopper 7. The output end of the drive motor 9 is fixedly connected to the agitator 12. The agitator 12 is driven by the drive motor 9, and its core function is to break up powder agglomerates. Continuous low-speed agitation keeps the powder in a loose state.

[0033] like Figure 3 and Figure 4 As shown, the turntable assembly 8 includes a barrier 13, an indexing turntable 15, and a weighing assembly 17. A motor drive assembly 4 is installed at the bottom of the platform 3. The output end of the motor drive assembly 4 is fixedly connected to the rotating shaft of the indexing turntable 15, enabling continuous and uniform rotation of the indexing turntable 15 to ensure the filling rhythm. Multiple mold cavities 16 are evenly arranged on the outer edge of the indexing turntable 15, and the size of the mold cavities 16 is adapted to the container to be filled (such as a 20kg sealed container).

[0034] The indexing turntable 15 is fitted with a concentric ring support 14 on its outer side, which is mounted on the upper surface of the platform 3 via support columns. The ring support 14 is semi-circular, with its inner side fitting with the outer side of the indexing turntable 15 with a clearance. The ring support 14 serves as a support plate for the container, and is flush with the conveying plane of the conveyor 2, eliminating the height step during container transfer.

[0035] The enclosure 13 is installed on the outer edge of the upper end face of the ring support 14 and is concentrically set with the indexing turntable 15. This can prevent the container from shifting or tipping over due to centrifugal force during rotation, ensuring stability throughout the filling process.

[0036] One end of the ring support 14 has a circular hole corresponding to the mold cavity 16. The weighing assembly 17 includes a tray 27 and a weighing sensor 28. The tray 27 is embedded in the circular hole, one end of the weighing sensor 28 is installed on the bottom of the tray 27, and the other end of the weighing sensor 28 is installed on the upper surface of the platform 3 through a bracket.

[0037] The position of the weighing component 17 is designated as the filling position, and the tray 27 is concentric with any mold cavity 16 that rotates to this position. When the container rotates to the filling position with the indexing turntable 15, the bottom of the container rests completely on the tray 27, and the weighing sensor 28 can provide real-time weight data, forming a closed-loop control with the auger conveyor component 6. When the weight reaches the set value (e.g., 20 kg / barrel), the auger conveyor component 6 immediately stops feeding to prevent overfilling or underfilling.

[0038] like Figure 3 As shown, the barrier assembly includes a stand 22. A rotary cylinder 23 is fixed to one side of the stand 22, and a baffle 24 is fixed to the output end of the rotary cylinder 23. A conveying channel is formed between the outer edge of the indexing turntable 15, the inner side of the enclosure 13, and the ring support 14. The end of the baffle 24 is provided with a guide portion 21 that points obliquely towards the conveying channel to prevent the container from getting stuck at the connection between the conveyor 2 and the conveying channel.

[0039] When a cavity 16 of the indexing turntable 15, carrying an empty container, rotates to the filling position and stops, the central control system determines that the filling state has begun. The central control system sends a closing command to the rotary cylinder 23, which drives the baffle 24 to rotate to the closed position. The main body of the baffle 24 blocks subsequent empty containers on the conveyor 2. After filling is completed, the central control system commands the motor drive assembly 4 to start, causing the indexing turntable 15 to rotate one cavity 16 angle, and the empty container in the previous cavity 16 rotates to the filling position. At the same time, the central control system sends an opening command to the rotary cylinder 23, which drives the baffle 24 to rotate rapidly to the open position. The first empty container on the conveyor 2 enters the empty cavity 16 of the indexing turntable 15 under the action of the conveying power.

[0040] like Figure 3 and Figure 4 As shown, the rotating drum assembly 10 is located on one side of the turntable assembly 8, and barcode information recognition is achieved by adjusting the circumferential angle of the container. The rotating drum assembly 10 includes a servo motor 20, which is fixed to the enclosure 13 by a support frame. A barcode scanner 11 corresponding to the filling position is installed on the enclosure 13. Multiple rollers 26 are evenly arranged on the inner edge of the mold cavity 16, and a rubber wheel 25 corresponding to the filling position is installed on one side of the enclosure 13. A first transmission pulley 18 is fixed to one end of the rubber wheel 25, and a second transmission pulley 19 is fixed to the output end of the servo motor 20. The second transmission pulley 19 is connected to the first transmission pulley 18 through a synchronous belt.

[0041] When the container is moved to the filling position, the barcode scanner 11 identifies the barcode information on the container. If no barcode information is detected, the central control system controls the servo motor 20 to start, which drives the rubber wheel 25 to rotate via a synchronous belt. The rubber wheel 25 drives the container to rotate circumferentially around its own central axis, thereby adjusting the position of the barcode circumferentially until it is scanned and recorded by the barcode scanner 11. At this point, the servo motor 20 stops, and the next filling process begins.

[0042] The embodiments described above are not exhaustive and do not limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the above description. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to effectively utilize the invention and its modifications. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A method for preparing zinc sulfide with a particle size of [missing information], characterized in that, The steps include the following: 1) Disperse 60-100 parts of zinc oxide powder in 230 parts of O / W type microemulsion by mass, add sulfuric acid of 30% by mass at 4 times the mass of zinc oxide powder, and stir continuously to obtain zinc sulfate microemulsion; 2) Hydrogen sulfide gas was introduced into the zinc sulfate microemulsion at a flow rate of 200 mL / min, the reaction temperature was maintained at 25 °C, and the mixture was stirred continuously to obtain a reaction suspension. 3) Transfer the reaction suspension to a centrifuge, collect the bottom precipitate, wash and dry it to obtain zinc sulfide primary product; 4) Add oleic acid to anhydrous ethanol and stir to obtain a coating solution with a mass concentration of 5% to 8%; 5) Disperse the zinc sulfide primary product in the coating liquid at a solid-liquid ratio of 1:10, stir continuously, and then transfer it to a vacuum drying oven for drying to obtain zinc sulfide powder with fine particle size. Finally, fill it into barrels and scan it into the warehouse to obtain the finished product.

2. The method for preparing zinc sulfide with a particle size according to claim 1, characterized in that: The O / W type microemulsion is formulated by compounding surfactant, mixed oil phase, co-surfactant and deionized water in a mass ratio of 1.8-2.2:5-6.5:0.8-1.2:28-32.

3. The method for preparing zinc sulfide with a particle size according to claim 2, characterized in that: The mixed oil phase is composed of liquid paraffin and cyclohexane in a mass ratio of 2:

1.

4. The method for preparing zinc sulfide with a particle size according to claim 2, characterized in that: The co-surfactant is n-hexanol.

5. The method for preparing zinc sulfide with a particle size according to claim 2, characterized in that: The surfactant is a compound of Tween80 and Span80 in a mass ratio of 3:

1.

6. The method for preparing zinc sulfide with a particle size according to claim 2, characterized in that: The zinc oxide powder has a particle size ≤ 5 μm.

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