Process for the preparation of fine particle size zinc sulfide

Abstract

The application relates to the technical field of zinc sulfide preparation, in particular to a preparation method of microparticle-diameter zinc sulfide, which comprises the following steps: dispersing zinc oxide powder in O / W type microemulsion, adding sulfuric acid dropwise to obtain zinc sulfate microemulsion; introducing hydrogen sulfide gas into the zinc sulfate microemulsion, maintaining a reaction temperature of 25 DEG C, continuously stirring to obtain a reaction suspension; transferring the reaction suspension to a centrifugal device, collecting the bottom precipitate, washing, drying to obtain zinc sulfide primary products; dispersing the zinc sulfide primary products in a coating liquid, continuously stirring, then transferring to a vacuum drying box for drying to obtain microparticle-diameter zinc sulfide powder, finally performing barrel filling through a filling device, scanning into a warehouse, and obtaining finished products. The O / W type microemulsion limits the reaction in the water core through a limited effect, directly locks the zinc sulfide particle diameter in a range corresponding to the size of the water core, and fundamentally avoids the problem of large particle diameter caused by free crystal growth in a conventional solution reaction.

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:

[0007] 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;

[0008] 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.

[0009] 3) transfer the reaction suspension to a centrifugal device, collect the bottom precipitate, wash, dry, and obtain the zinc sulfide primary product;

[0010] 4) add oleic acid to anhydrous ethanol, stir, and obtain a coating liquid with a mass concentration of 5-8%;

[0011] 5) disperse the zinc sulfide primary product in the coating liquid at a solid-liquid ratio of 1:10, continuously stir, then transfer to a vacuum drying oven for drying, obtain the microparticle size zinc sulfide powder, and finally pass through a filling device to be filled into a barrel, scanned into a warehouse, and obtain the finished product.

[0012] Preferably, the O / W type microemulsion is compounded from the surfactant, the mixed oil phase, the co-surfactant, and deionized water at a mass ratio of 1.8-2.2:5-6.5:0.8-1.2:28-32.

[0013] Preferably, the mixed oil phase is compounded from liquid paraffin and cyclohexane at a mass ratio of 2:1.

[0014] Preferably, the co-surfactant is n-hexanol.

[0015] Preferably, the surfactant is compounded from Tween 80 and Span 80 at a mass ratio of 3:1.

[0016] Preferably, the particle size of the zinc oxide powder is ≤5 μm.

[0017] After the above technical solutions are adopted, the application has the following beneficial effects:

[0018] The O / W type microemulsion limits the reaction in the water core through a confinement effect, directly locks the particle size of the zinc sulfide in a range comparable to the size of the water core, and fundamentally avoids the problem of large particle size caused by free growth of crystals in a conventional solution reaction.

[0019] The microparticle size zinc sulfide powder can be stably metered and batch-packaged through a special filling device, and the powder loss or pollution caused by manual operation is avoided. The container is driven to rotate before filling by a rotating barrel assembly, and a code scanner can identify the container information in real time, so that the filling and product information are matched. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0021] Figure 1 It is a front view of the filling device;

[0022] Figure 2 Figure 1 is a perspective view of a filling device;

[0023] Figure 3 Figure 2 is a schematic view of a rotating disc assembly;

[0024] Figure 4 Figure 3 is a schematic view of a weighing assembly.

[0025] In the figure: 1 - frame, 2 - conveyor, 3 - table plate, 4 - motor drive assembly, 5 - material inlet, 6 - auger conveying assembly, 7 - hopper, 8 - rotating disc assembly, 9 - drive motor, 10 - rotating barrel assembly, 11 - code scanner, 12 - stirring paddle, 13 - fence, 14 - ring support, 15 - index rotating disc, 16 - mold cavity, 17 - weighing assembly, 18 - first transmission pulley, 19 - second transmission pulley, 20 - servo motor, 21 - guide, 22 - stand, 23 - rotary cylinder, 24 - baffle, 25 - rubber wheel, 26 - roller, 27 - tray, 28 - weighing sensor. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with specific examples. It should be understood that the specific examples described herein are configured only to explain the present application and are not configured to limit the present application. The present application can be implemented without some of these specific details by those skilled in the art. The following description of the examples is only to provide a better understanding of the present application by showing examples of the present application.

[0027] Example 1

[0028] The present embodiment provides a preparation method of microparticle size zinc sulfide, and the following are specific preparation steps and technical details of the preparation method.

[0029] S1, O / W microemulsion preparation

[0030] A 30℃ water bath and 300r / min stirring are maintained, and the surfactant, mixed oil phase, co-surfactant and deionized water are weighed according to the mass ratio of 1.8:5:0.8:28. After mixing, continue to stir for 30min to obtain an O / W microemulsion with a total mass of 230 parts (mass parts, the same below).

[0031] Among them, the mixed oil phase is compounded by liquid paraffin and cyclohexane according to the mass ratio of 2:1, the co-surfactant is n-hexanol, and the surfactant is compounded by Tween80 and Span80 according to the mass ratio of 3:1.

[0032] The role of the O / W microemulsion is to build the micro-reaction cavity of oil core-water continuous phase and limit the growth of subsequent zinc sulfide particles.

[0033] S2, Preparation of zinc sulfate microemulsion

[0034] Start mechanical stirring (300 r / min) and ultrasonic dispersion (500 W, 25 kHz), maintain 30℃, and disperse 60 parts of zinc oxide powder with a particle size of ≤5 μm in the water core of the O / W microemulsion. At a drop rate of 6 mL / min, drop 4 times the mass of zinc oxide powder of 30% sulfuric acid, and continue to react for 15 min after the drop is completed to obtain a zinc sulfate microemulsion.

[0035] S3, Preparation of zinc sulfide suspension by hydrogen sulfide gas reaction

[0036] Pass hydrogen sulfide gas into the zinc sulfate microemulsion through the porous gas distributor at the bottom of the reaction cavity at a flow rate of 200 mL / min, adjust the stirring speed to 600 r / min, maintain a reaction temperature of 25℃, continue stirring for 30 min, stop the gas delivery and maintain the reaction for 10 min to obtain a reaction suspension.

[0037] S4, Separation and purification of zinc sulfide primary product

[0038] Centrifuge at 8000 r / min for 15 min, collect the white precipitate at the bottom. Wash with 80℃ deionized water for 3 times, collect the white precipitate at the bottom again, and place in a vacuum drying oven at 60℃ for 2 h to obtain a zinc sulfide primary product.

[0039] S5, Oleic acid coating and product preparation

[0040] Add oleic acid to anhydrous ethanol, stir to obtain a coating solution with a mass concentration of 5%. Disperse the zinc sulfide primary product in the coating solution at a solid-liquid mass ratio of 1:10, stir at a speed of 300 r / min, continue stirring for 15 min, then transfer to a vacuum drying oven at 60℃ for 2 h, and then perform airflow disaggregation to obtain a zinc sulfide powder with a particle size. Finally, fill the barrel through a filling device, scan into a warehouse, and obtain a zinc sulfide product with an average particle size of 1.56 μm.

[0041] Oleic acid coating can isolate moisture and oxygen in the air to avoid agglomeration or oxidation of zinc sulfide during subsequent filling, storage, and transportation, and can be removed by calcination during application to ensure the purity of zinc sulfide.

[0042] Example 2

[0043] Based on Example 1, the material parts are changed without changing the method flow, and the specific steps are as follows:

[0044] 1) According to the mass ratio 2:5.5:1:30, the surfactant, mixed oil phase, co-surfactant, deionized water are weighed, mixed and stirred for 30 min to obtain an O / W microemulsion;

[0045] 2) According to the mass fraction, 80 parts of zinc oxide powder are dispersed in 230 parts of O / W microemulsion, 30% sulfuric acid is added at 4 times the mass of zinc oxide powder, and stirring is continued to obtain a zinc sulfate microemulsion;

[0046] 3) Hydrogen sulfide gas is introduced into the zinc sulfate microemulsion at a flow rate of 200 mL / min, the reaction temperature is maintained at 25°C, and stirring is continued to obtain a reaction suspension;

[0047] 4) The reaction suspension is transferred to a centrifugal device, the bottom precipitate is collected, washed, and dried to obtain a zinc sulfide primary product;

[0048] 5) Oleic acid is added to anhydrous ethanol and stirred to obtain a coating solution with a mass concentration of 6%;

[0049] 6) The zinc sulfide primary product is dispersed in the coating solution at a solid-liquid ratio of 1:10, stirring is continued, then it is transferred to a vacuum drying oven for drying to obtain a microparticle size zinc sulfide powder, which is finally filled into a barrel by a filling device, scanned into a warehouse, and the average particle size of the finished zinc sulfide product is 1.28 μm.

[0050] Example 3

[0051] Based on Example 1, the material fractions are changed without changing the method flow, and the specific steps are as follows:

[0052] 1) According to the mass ratio 2.2:6.5:1.2:32, the surfactant, mixed oil phase, co-surfactant, deionized water are weighed, mixed and stirred for 30 min to obtain an O / W microemulsion;

[0053] 2) According to the mass fraction, 100 parts of zinc oxide powder are dispersed in 230 parts of O / W microemulsion, 30% sulfuric acid is added at 4 times the mass of zinc oxide powder, and stirring is continued to obtain a zinc sulfate microemulsion;

[0054] 3) Hydrogen sulfide gas is introduced into the zinc sulfate microemulsion at a flow rate of 200 mL / min, the reaction temperature is maintained at 25°C, and stirring is continued to obtain a reaction suspension;

[0055] 4) The reaction suspension is transferred to a centrifugal device, the bottom precipitate is collected, washed, and dried to obtain a zinc sulfide primary product;

[0056] 5) Oleic acid is added to anhydrous ethanol and stirred to obtain a coating solution with a mass concentration of 8%;

[0057] 6) According to the solid-liquid ratio 1:10, the zinc sulfide primary product is dispersed in the coating liquid, continuous stirring, and then transferred to the vacuum drying oven for drying, to obtain the microparticle size zinc sulfide powder, and finally through the filling equipment, the scanning into the warehouse, the average particle size of 1.78 μm of zinc sulfide finished product is obtained.

[0058] Comparative Example 1

[0059] Based on Example 1, the relevant steps of the O / W microemulsion are removed, and the zinc oxide powder is directly reacted with sulfuric acid, to obtain the average particle size of 6.31 μm of zinc sulfide finished product.

[0060] The present application also provides a preparation device for microparticle size zinc sulfide, to realize the stable metering and batch packaging of microparticle size zinc sulfide, and avoid the powder loss or pollution caused by manual operation.

[0061] As shown in Figure 1 and Figure 3 , the filling equipment includes a frame body 1. The frame body 1 is equipped with a table plate 3, and the table plate 3 is installed with a rotating disc assembly 8. Through indexing positioning, real-time weighing, and container limiting, the filling precision and consistency of each batch of zinc sulfide powder are ensured. A conveyor 2 is installed on one side of the table plate 3 for connecting the rotating disc assembly 8. The conveyor 2 is provided with a blocking assembly on one side to isolate and guide the batched containers to be filled into the rotating disc assembly 8.

[0062] As shown in Figure 2 , a hopper 7 is erected on the top of the frame body 1, and the bottom of the hopper 7 is provided with an auger conveying assembly 6. One end of the bottom of the auger conveying assembly 6 is provided with a discharging port 5 corresponding to the rotating disc assembly 8. The inside of the hopper 7 is installed with a stirring paddle 12, and the hopper 7 is fixed with a driving motor 9 on one side. The output end of the driving motor 9 is fixedly connected with the stirring paddle 12. The internal stirring paddle 12 is driven by the driving motor 9, and the core function is to break the powder agglomeration, which can maintain the loose state of the powder through continuous low-speed stirring.

[0063] As shown in Figure 3 and Figure 4 , the rotating disc assembly 8 includes a surrounding fence 13, an indexing rotating disc 15, and a weighing assembly 17. The bottom of the table plate 3 is installed with a motor driving assembly 4, and the output end of the motor driving assembly 4 is fixedly connected with the rotating shaft of the indexing rotating disc 15, to realize the continuous and uniform rotation of the indexing rotating disc 15, and to ensure the filling rhythm. The outer edge of the indexing rotating disc 15 is uniformly provided with a plurality of mold cavities 16, and the size of the mold cavities 16 is adapted to the containers to be filled (such as 20 kg sealed barrels).

[0064] The outside of the indexing rotating disc 15 is sleeved with a ring support 14 concentric with it, and the ring support 14 is installed on the upper end face of the table plate 3 through supporting columns. The ring support 14 is in the form of a semi-ring, and the inside is gap-fitted with the outside of the indexing rotating disc 15. The ring support 14 serves as a support plate for carrying containers, and is aligned with the conveying plane of the conveyor 2, to eliminate the height step of container transfer.

[0065] The enclosure 13 is installed on the upper end face of the ring support 14 and is arranged concentrically with the indexing turntable 15 to prevent the container from deviating or tilting due to centrifugal force during rotation and ensure stability during the entire filling process.

[0066] The ring support 14 is provided with 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, and one end of the weighing sensor 28 is installed on the bottom of the tray 27. The other end of the weighing sensor 28 is installed on the upper end face of the table plate 3 through a support.

[0067] The position of the weighing assembly 17 is set as the filling position, and the tray 27 is concentric with any mold cavity 16 that is rotated to this position. When the container is rotated to the filling position with the indexing turntable 15, the bottom of the container completely falls on the tray 27, and the weighing sensor 28 can feedback the weight data in real time, forming a closed-loop control with the auger conveying assembly 6. When the weight reaches the set value (such as 20 kg / barrel), the auger conveying assembly 6 immediately stops feeding to avoid overloading or underloading.

[0068] As shown in Figure 3 , the blocking assembly includes a stand 22. One side of the stand 22 is fixed with a rotary cylinder 23, and the output end of the rotary cylinder 23 is fixed with a baffle 24. The outer edge of the indexing turntable 15, the inner side of the enclosure 13, and the ring support 14 form a conveying channel. The end of the baffle 24 is provided with a guide part 21 that is inclined to the conveying channel to avoid the container being stuck at the junction of the conveyor 2 and the conveying channel.

[0069] When a certain mold cavity 16 of the indexing turntable 15 carries an empty container and rotates to the filling position and stops, the central control system determines that the filling state is entered. The central control system sends a closing instruction to the rotary cylinder 23, the rotary cylinder 23 drives the baffle 24 to rotate to the closed position, and the baffle 24 blocks the subsequent empty container on the conveyor 2. After filling is completed, the central control system instructs the motor drive assembly 4 to start, which drives the indexing turntable 15 to rotate by an angle of one mold cavity 16, and the empty container in the previous mold cavity 16 is rotated to the filling position. At the same time, the central control system sends an opening instruction to the rotary cylinder 23, and the cylinder drives the baffle 24 to quickly rotate to the open position. The first empty container on the conveyor 2 enters the empty mold cavity 16 of the indexing turntable 15 under the action of the conveying power.

[0070] As shown in Figure 3 and Figure 4As shown, the rotating barrel assembly 10 is arranged on one side of the rotating disc assembly 8, and the bar code information is identified by adjusting the circumferential angle of the container. The rotating barrel assembly 10 comprises a servo motor 20, the servo motor 20 is fixed to the fence 13 through a support frame, and a code scanner 11 corresponding to the filling position is installed on the fence 13. The inner edge of the mold cavity 16 is uniformly provided with a plurality of rollers 26, and a rubber wheel 25 corresponding to the filling position is installed on one side of the fence 13. One end of the rubber wheel 25 is fixed with a first transmission pulley 18, and the output end of the servo motor 20 is fixed with a second transmission pulley 19, and the second transmission pulley 19 is connected with the first transmission pulley 18 through a synchronous belt.

[0071] When the filled container rotates to the filling position, the code scanner 11 identifies the bar code information on the container. If the bar code information cannot be detected, the central control system controls the servo motor 20 to start, and drives the rubber wheel 25 to rotate through the synchronous belt. The rubber wheel 25 drives the container to rotate around its central axis, so as to realize the circumferential adjustment of the bar code position, until it is scanned and recorded by the code scanner 11, the servo motor 20 stops, and the next filling process starts.

[0072] According to the above embodiments of the present application, these embodiments do not describe all the details and are not limited to the specific embodiments. Obviously, according to the above description, many modifications and changes can be made. The present description selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well utilize the present application and make modifications and uses on the basis of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing zinc sulfide with a particle size of [missing information], characterized in that, Includes the following steps: 1) Disperse 60-100 parts of zinc oxide powder in 230 parts of O / W microemulsion by mass. The O / W microemulsion is prepared 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. Add 30% sulfuric acid at 4 times the mass of zinc oxide powder and stir continuously to obtain zinc sulfate microemulsion. 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 composed of Tween80 and Span80 in a mass ratio of 3:

1. 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 the powder into barrels using filling equipment, scan it into the warehouse, and the finished product is obtained.

2. The method for preparing zinc sulfide with a particle size according to claim 1, characterized in that: The zinc oxide powder has a particle size ≤ 5 μm.

Images