A multi-kettle multi-parameter regulation based particle size controllable reduction system and method

Abstract

The application discloses a kind of particle size controllable reduction system and method based on multiple kettle multiple parameter regulation, including multiple parallel reduction kettle and a mixing kettle;Based on the particle size distribution requirement of silver powder product, determine the number of reduction kettle and require the silver powder particle size distribution formed by each reduction kettle, the reaction raw material of each reduction kettle is same, based on the silver powder particle size distribution requirement formed by each reduction kettle, determine the reaction temperature interval of each reduction kettle, reduction degree PH interval and heating speed;Each reduction kettle is connected with reaction material by independent material conveying pipeline, and each reduction kettle is independent reaction and regulation unit and is equipped with complete online detection component and accurate execution component, to realize the automatic adjustment of each process parameter;Mixing kettle, different particle size of silver powder slurry formed after the reaction of each reduction kettle is input into mixing kettle and mixed for a predetermined time, and then washed, dispersed, dried and detected to obtain silver powder product.The present application effectively solves the three core pain points of traditional reduction preparation equipment.

Description

Technical Field

[0001] This invention relates to the field of wet reduction preparation equipment for powders, and in particular to a particle size controllable reduction system and method based on multi-reactor and multi-parameter regulation. Background Technology

[0002] The core principle of preparing powder materials by liquid-phase chemical reduction is as follows: soluble metal salts / oxides are reduced to powder nuclei using a reducing agent. These nuclei then grow and mature to form the finished powder. The dynamic balance between the nucleus formation rate and the growth rate determines the powder particle size—a fast formation rate and slow growth rate result in small particle size, and vice versa. pH determines the reduction reaction rate, temperature affects both the formation and growth rates, and heating power regulates the growth rate by controlling the heating rate and the reaction heat balance. These three factors are the core parameters for particle size control. Traditional reduction processes often employ "single-parameter control" or "simple linkage of two parameters," which have significant drawbacks: First, particle size is controlled solely by adjusting temperature or pH, resulting in a limited control dimension, low particle size control precision, and an inability to meet the demands of high-end powders. Second, heating power is used only as a temperature control aid, without a targeted heating power mode designed according to the target particle size, leading to uncontrolled heating rates, uneven crystal growth, and a wide particle size distribution. Third, multi-stage processes using uniform parameters cannot simultaneously produce powders of different particle sizes, resulting in low production efficiency. Fourth, reliance on manual parameter adjustment lacks precise closed-loop control logic, leading to large parameter fluctuations and poor product quality stability.

[0003] Chinese utility model patent CN203292491U discloses an apparatus for preparing ultrafine silver powder using a liquid-phase reduction method. The apparatus consists of a speed-regulating stirrer, a pH meter, a cylindrical hollow reactor, a circulating water bath, a small constant flow pump, and a pH adjustment device. The reactor is placed in the circulating water bath for temperature control. The pH of the reaction system is monitored in real time by the pH meter. The pH value and the rate of addition of the reducing agent are adjusted using the pH adjustment device and the small constant flow pump, respectively. The stirring speed is adjusted in conjunction with the speed-regulating stirrer. By controlling these parameters, the initial control of the silver powder particle size and morphology is achieved. It has the following disadvantages: ① It only adopts a single reactor structure and does not have a multi-reactor independent control design, so it cannot produce powders of different particle sizes at the same time, resulting in low production flexibility and efficiency; ② Although it achieves the control of pH, temperature and stirring speed, it does not incorporate heating power into the control system, and there is no multi-parameter collaborative control logic, resulting in low particle size distribution control accuracy and difficulty in adjustment; ③ It relies on metering equipment such as small constant flow pumps to control the feeding, resulting in high equipment purchase and maintenance costs, and the parameter control is in an open-loop mode, which is prone to deviations and leads to unstable product quality.

[0004] Chinese invention patent application CN1876291A discloses a method for preparing nano-nickel powder using a liquid-phase fluidized bed reduction method. This method includes: using a fluidized bed reactor as the reduction substrate, dividing the reactor into a nucleation section and a crystal growth section; controlling the residence time of the reaction liquid in the two sections to regulate the nickel powder particle size; achieving uniform temperature control using thermal radiation / microwave heating; adjusting the pH of the reaction system to 8-12 and the reduction temperature to 60-100℃; and accelerating the reaction with a catalyst and reducing agent to achieve the preparation of nano-nickel powder. Simultaneously, continuous production is achieved through reaction liquid circulation. It has the following disadvantages: ① Although the reaction process is segmented, it is a single reactor structure without multiple independent control units, and it is impossible to independently set the pH, temperature, and heating power parameters of each reaction segment, resulting in weak multi-parameter coordinated control capability; ② The heating method only achieves constant temperature control and does not use heating power as an independent control parameter, so it is impossible to control the heating rate by adjusting the power, resulting in low matching degree between crystal nucleation and growth rate, and narrow particle size control range (only 30~100nm); ③ The equipment structure is complex, the fluidized bed has high requirements for raw materials and operation, and it is only suitable for the preparation of nano-nickel powder, and cannot be flexibly adapted to other metals and oxide powders such as silver and copper, resulting in poor equipment versatility.

[0005] Chinese invention patent application CN118204509A discloses an apparatus and method for the mass production of ultrafine spherical silver powder via spray pyrolysis. The method includes: connecting multiple ultrasonic atomizers in parallel to achieve mass production of ultrafine spherical silver powder through spray pyrolysis; utilizing atomizers to improve atomization efficiency; and controlling the silver powder particle size and morphology by adjusting atomization parameters and pyrolysis temperature, resulting in high raw material utilization and meeting the basic particle size requirements of different applications. However, it has the following drawbacks: ① It is a dedicated spray pyrolysis device, not a multi-stage liquid-phase reduction structure, lacking independent pH and heating power control components, making multi-parameter coordinated control impossible in a liquid-phase reduction system; ② Particle size distribution adjustment is difficult, only allowing for coarse adjustment through atomization and pyrolysis parameters, failing to precisely control powder particle size and distribution width, resulting in poor product consistency; ③ The equipment is highly specialized, only suitable for the spray pyrolysis preparation of silver powder, incompatible with liquid-phase reduction processes for other powders, and has high cost and difficult maintenance.

[0006] Therefore, there is an urgent need to develop a powder particle size reduction process based on the coordinated control of three parameters: pH, temperature, and heating power. Combined with a multi-reactor independent control mode, this process can achieve precise and flexible control of powder particle size, with a wide particle size control range and broad adaptability, thereby improving production efficiency and product quality stability. Summary of the Invention

[0007] In view of this, the present invention provides a particle size controllable reduction system based on multi-reactor, multi-parameter regulation, comprising multiple parallel reduction reactors and a mixing reactor; the number of reduction reactors and the required silver powder particle size distribution in each reduction reactor are determined based on the particle size distribution requirements of the silver powder product; and the reaction conditions for each reduction reactor are determined based on the required silver powder particle size distribution in each reduction reactor; wherein, The reaction raw materials in each reduction reactor are the same, and the mass ratio is: silver nitrate: total alkali solution: total reducing agent = 800-850: 120-150: 536-600; The reaction temperature of the reduction vessel is 22℃~85℃. The reaction temperature range for each reduction vessel is determined within this range based on the desired silver powder particle size distribution. Different heating rates are used depending on the desired silver powder particle size distribution for each reduction vessel. For silver powder with a small particle size of D50 of 0.02~0.05μm, the heating rate is 0.5~1.0℃ / min; For medium-sized silver powder with a D50 of 0.05~0.10μm, the heating rate is 1.0~1.5℃ / min; For large-particle-size silver powder with a D50 of 0.10~0.20μm, the heating rate is 1.5~2.5℃ / min; The corresponding heating power is determined based on different heating rates; The pH range of reduction degree is determined based on the different silver powder particle sizes required to be formed in each reduction reactor. Each reduction vessel is connected to the reactants via an independent material delivery pipeline; Each reduction vessel is an independent reaction and control unit, equipped with complete online monitoring components and precise execution components; among them, The complete online detection component includes an online pH electrode, a temperature sensor, and a heating power acquisition module, which are used to collect the pH value, temperature, and actual output power of the heating component in the reaction system in real time. The precise execution components include an alkali metering pump, a jacketed heating assembly, a cooling water solenoid valve, a variable frequency magnetic stirrer, and a flow control valve. The system relies on a complete online detection component to collect parameters of the reaction system inside the reactor in real time and feed them back to the corresponding independent control unit. After comparing them with the preset values, it outputs adjustment commands. The alkali metering pump, heating / cooling components, stirrer and flow control valve operate synchronously to dynamically correct pH value, temperature, power and feed rate, forming a closed-loop control and realizing automatic adjustment of various process parameters. The mixing vessel is used to feed silver powder slurries of different particle sizes formed after the reaction in each reduction vessel into the mixing vessel and mix them for a predetermined time. After washing, dispersing, drying, and passing the inspection, the silver powder product is obtained.

[0008] This invention also provides a particle size controllable reduction method based on multi-reactor, multi-parameter regulation, implemented by the aforementioned particle size controllable reduction system, and the method includes the following steps: Step 1: Preheat the silver nitrate solution, alkaline solution, and reducing agent solution to the predetermined temperature for later use; Step 2: Add a predetermined amount of silver nitrate solution to each reduction vessel, set the heating power of each reduction vessel, and control its jacketed heating element to heat the silver nitrate solution in the reduction vessel to the required temperature value; use a variable frequency magnetic stirrer to stir the solution in the reduction vessel; add alkali solution to the reduction vessel according to the preset pH value requirement of each reduction vessel through an alkali metering pump; add a predetermined amount of reducing agent to the reduction vessel through a flow regulating valve; collect the pH value, temperature and actual output power of the reaction system in the vessel in real time through an online pH electrode, temperature sensor and heating power acquisition module, and adjust the amount of alkali solution and reducing agent added accordingly based on the detection data; generate silver powder slurry for each reduction vessel. Step 3: Input the silver powder slurry generated from each reduction vessel into the mixing vessel and mix for a predetermined time; then wash, disperse, dry, and test to obtain the silver powder product.

[0009] Furthermore, the temperatures of the silver solution, the alkaline solution, and the reducing agent are controlled at 20~60℃, 20~40℃, and 20~40℃, respectively.

[0010] Furthermore, the alkali feed rate is 10~50 mL / min.

[0011] Furthermore, the silver solution is a silver nitrate solution.

[0012] Furthermore, the alkali is one or more of sodium carbonate, sodium hydroxide, and ammonia water, and the total alkali concentration is 30% to 50%.

[0013] Furthermore, the reducing agent is one or more of triethanolamine, polyvinyl alcohol, hydrazine hydrate, and polyvinylpyrrolidone, with a concentration of 20% to 40%.

[0014] Furthermore, the reaction temperature range is determined within the reaction temperature range according to the different silver powder particle sizes that each reduction vessel needs to form. The reaction temperature range can be: 22~25℃, 26~30℃, 31~35℃, 36~40℃, ..., or 81~85℃.

[0015] Furthermore, the pH range of the reduction degree is determined according to the different silver powder particle sizes that each reduction vessel needs to form. The pH range of the reduction degree can be: 7.5~7.8, 7.8~8.1, 8.1~8.4, 8.4~8.7, ..., 12.3~12.6, or 12.6~13.0.

[0016] Furthermore, the heating power is determined based on the different silver powder particle sizes required to be formed in each reduction vessel. The heating power can be: 10KW, 12KW, 13KW, 14KW, ..., or 50KW.

[0017] This equipment achieves three core advantages through the aforementioned structural design: First, it adopts a multi-vessel modular independent control design, allowing each reduction vessel to independently set pH, temperature, and heating power parameters, supporting simultaneous continuous production of powders of various specifications, significantly improving equipment utilization and production flexibility; Second, it constructs a three-parameter synergistic closed-loop control system of pH, temperature, and heating power, precisely matching the crystal nucleus generation and growth rate through real-time linkage of detection and execution components, achieving precise control of powder particle size and distribution width, and controllable particle size fluctuations; Third, it eliminates the need for expensive dedicated metering and control equipment, simplifying the equipment structure through modular integrated design, making operation and maintenance convenient, significantly reducing equipment procurement and maintenance costs, while ensuring the stability and good dispersibility of powder product quality, effectively solving the core pain points of traditional reduction preparation equipment. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the particle size controllable reduction system based on multi-reactor and multi-parameter regulation of the present invention. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and specific examples, but the implementation of the present invention is not limited thereto.

[0020] Addressing the pain points of traditional reduction equipment, such as centralized parameter control in a single reactor, low particle size control precision, poor production flexibility, and reliance on complex control equipment, this invention optimizes the modular structure of the reactor and the multi-parameter independent control system to achieve precise control of powder particle size. It also supports the simultaneous production of silver powder of multiple specifications, significantly improving equipment adaptability and production efficiency, reducing equipment procurement and maintenance costs, and is suitable for the large-scale and customized preparation of nano / micro silver powder. This equipment features a multi-vessel modular independent control structure. The number of reduction vessels can be customized according to production needs. Each reduction vessel is an independent reaction and control unit, connected by independent material delivery pipelines. Each reduction vessel is equipped with complete online detection and precision execution components. The detection components include an online pH electrode, a temperature sensor, and a heating power acquisition module, which can collect the pH value, temperature, and actual output power of the heating components in the reaction system in real time. During production, the heating power of each reduction vessel is set, silver nitrate solution is added, and after reaching the required temperature, the set amount of alkali solution is added according to the pH requirement. Finally, the reducing agent is added. The execution components include an alkali metering pump, a jacketed heating component, a cooling water solenoid valve, a variable frequency magnetic stirrer, and a flow regulating valve, which can accurately adjust the corresponding parameters based on the detection data. All detection and execution components of the reduction reactors are independently controlled by control units, allowing for independent setting of different pH, temperature, and heating power parameters for single or multiple reactors. Each reduction reactor can independently adjust its own reaction system's pH, reaction temperature, and heating power mode according to the target silver powder particle size requirement, achieving multi-parameter coordinated control. Flow control valves are installed in the material conveying pipelines and raw material feed pipelines to achieve flexible control of feed rate and material delivery rate. Each independent reduction reactor, as the core reaction unit, captures reaction parameters in real time through its matching detection components, constructing a closed-loop control logic of pH-temperature-heating power. This enables precise coordinated control of pH, temperature, and heating power within a single reactor, providing hardware support for precise control of silver powder particle size. The detection components provide accurate real-time data for parameter control, ensuring the accuracy of the control direction and amplitude. The execution components, as the execution carriers of parameter control, respectively complete pH adjustment, coordinated control of temperature and heating power, material mixing, and feed rate control, ensuring that the reaction system parameters remain stable within the set range.

[0021] The temperatures of the silver solution, alkaline solution, and reducing agent are respectively controlled at 20~60℃: 20~40℃: 20~40℃; The mass ratio of the silver raw material, total alkali solution and total reducing agent is 800~850:120~150:536~600; The silver raw material is silver nitrate; The alkali is one or more of sodium carbonate, sodium hydroxide, and ammonia water; The reducing agent is one or more of triethanolamine, polyvinyl alcohol, hydrazine hydrate, and polyvinylpyrrolidone.

[0022] The concentration of silver nitrate is 0.8~3.0 mol / L; The alkali concentration is 30%~50%; The concentration of the reducing agent is 20%~40%; The reaction temperature ranges for different reduction reactors are: 22~25℃, 26~30℃, 31~35℃, 36~40℃, ..., or 81~85℃; The pH ranges for different reduction degrees are: 7.5~7.8, 7.8~8.1, 8.1~8.4, 8.4~8.7, ..., 12.3~12.6, or 12.6~13.0; The heating power of the different reduction reactors is: 10KW, 12KW, 13KW, 14KW, ..., or 50KW; The particle size controllable reduction equipment and process based on multi-reactor and multi-parameter regulation is as follows: Step S1: Preheat the silver nitrate solution, alkali solution, and reducing agent solution to a certain temperature (20-50℃) for later use.

[0023] Step S2: Each reduction vessel is an independent reaction and control unit, connected to the reaction materials via an independent material delivery pipeline. Each reduction vessel is equipped with a complete online detection component and a precision execution component. The detection component includes an online pH electrode, a temperature sensor, and a heating power acquisition module, which can collect the pH value, temperature, and actual output power of the heating component in the reaction system in real time. During production, the heating power of each reduction vessel is set, silver nitrate solution is added, and after reaching the required temperature value, the set amount of alkali solution is added according to the pH value requirements. Finally, the reducing agent is added. The execution component includes an alkali metering pump, a jacketed heating component, a cooling water solenoid valve, a variable frequency magnetic stirrer, and a flow regulating valve, which can accurately adjust the corresponding parameters based on the detection data. The cooling water solenoid valve is used to work with the heating component to regulate the system temperature, achieving constant and precise temperature control; the variable frequency magnetic stirrer is used to mix the materials, ensuring uniform parameters throughout the reaction system and improving the consistency and dispersibility of the silver powder particle size. The flow regulating valve, combined with the pipeline flow detection element, collects flow data in real time. The control system compares the data with the set value and then fine-tunes the valve opening to accurately control the feed flow rate and feed speed of materials such as silver nitrate and reducing agent, ensuring a stable feeding ratio.

[0024] Step S3: After the reaction in each reduction vessel is completed, the silver powder slurry with different particle sizes is fed into the mixing vessel and mixed for a predetermined time. Then, after washing, dispersing, drying, and passing the inspection, the silver powder product is obtained.

[0025] Example 1 (1) Preheat the silver nitrate solution, alkaline solution and reducing agent solution to a certain temperature of 25℃ for later use.

[0026] (2) Three reduction vessels, each of which is an independent reaction and control unit. The reduction vessels are connected by independent material conveying pipelines. Each reduction vessel is equipped with a complete online detection component and a precision execution component. The detection component includes an online pH electrode, a temperature sensor, and a heating power acquisition module, which can collect the pH value, temperature, and actual output power of the heating component of the reaction system in the vessel in real time. During production, the heating power of each reduction vessel is set to 12KW, 13KW, and 14KW respectively. Silver nitrate solution is added respectively, and after reaching the required temperatures of 31-35℃, 36-40℃, and 41-45℃ respectively, the set amount of alkali solution is added according to the requirements of pH=8.6-9.0, 9.1-9.5, and 9.6-10.0 respectively. Finally, the reducing agent is added respectively. The execution component includes an alkali metering pump, a jacketed heating component, a cooling water solenoid valve, a variable frequency magnetic stirrer, and a flow regulating valve, which can complete the precise adjustment of the corresponding parameters according to the detection data.

[0027] (3) After a certain reaction time, the silver powder slurry is washed, dispersed, dried and tested to obtain the silver powder product.

[0028] Example 2 (1) Preheat the silver nitrate solution, alkaline solution and reducing agent solution to a certain temperature of 25℃ for later use.

[0029] (2) Three reduction vessels, each of which is an independent reaction and control unit. The reduction vessels are connected by independent material conveying pipelines. Each reduction vessel is equipped with a complete online detection component and a precision execution component. The detection component includes an online pH electrode, a temperature sensor, and a heating power acquisition module, which can collect the pH value, temperature, and actual output power of the heating component in the reaction system in real time. During production, the heating power of each reduction vessel is set to 15KW, 16KW, and 17KW respectively. Silver nitrate solution is added respectively, and the required temperatures are reached respectively = 41-45℃, 46-50℃, and 51-55℃. Then, the set amount of alkali solution is added according to the requirements of pH = 7.5-8.0, 8.1-8.5, and 8.6-9.0 respectively. Finally, the reducing agent is added respectively. The execution component includes an alkali metering pump, a jacketed heating component, a cooling water solenoid valve, a variable frequency magnetic stirrer, and a flow regulating valve, which can complete the precise adjustment of the corresponding parameters according to the detection data.

[0030] (3) After a certain reaction time, the silver powder slurry is washed, dispersed, dried and tested to obtain the silver powder product.

[0031] Example 3 (1) Preheat the silver nitrate solution, alkaline solution and reducing agent solution to a certain temperature of 25℃ for later use.

[0032] (2) Three reduction vessels, each of which is an independent reaction and control unit. The reduction vessels are connected by independent material conveying pipelines. Each reduction vessel is equipped with a complete online detection component and a precision execution component. The detection component includes an online pH electrode, a temperature sensor, and a heating power acquisition module, which can collect the pH value, temperature, and actual output power of the heating component in the reaction system in real time. During production, the heating power of each reduction vessel is set to 18KW, 19KW, and 20KW respectively. Silver nitrate solution is added respectively, and the required temperatures are reached respectively = 56-60℃, 61-65℃, and 66-70℃. Then, the set amount of alkali solution is added according to the requirements of pH = 7.0-7.5, 7.6-8.0, and 8.1-8.5 respectively. Finally, the reducing agent is added respectively. The execution component includes an alkali metering pump, a jacketed heating component, a cooling water solenoid valve, a variable frequency magnetic stirrer, and a flow regulating valve, which can complete the precise adjustment of the corresponding parameters according to the detection data.

[0033] (3) After a certain reaction time, the silver powder slurry is washed, dispersed, dried and tested to obtain the silver powder product.

[0034] Comparative Example 1 This comparative example provides a method for preparing silver powder. The difference from Example 1 is that during the reduction reaction, the reactor is turned on and stirred. The heating power is 12KW. Silver nitrate solution is added all at once. After reaching the required temperature of 36-40℃, the set amount of alkali solution is added according to the pH requirement of 9.1-9.5. Finally, the reducing agent is added. After the reaction is completed, the material is discharged and the stirring is turned off.

[0035] Comparative Example 2 This comparative example provides a method for preparing silver powder. The difference from Example 1 is that during the reduction reaction, the reactor is turned on and stirred. The heating power is 12KW. Silver nitrate solution is added all at once. After reaching the required temperature of 56-60℃, the set amount of alkali solution is added according to the pH requirement of 8.1-8.5. Finally, the reducing agent is added. After the reaction is completed, the material is discharged and the stirring is turned off.

[0036] Comparative Example 3 This comparative example provides a method for preparing silver powder. The difference from Example 1 is that during the reduction reaction, the reactor is turned on and stirred. The heating power is 18KW. Silver nitrate solution is added all at once. After reaching the required temperature of 36-40℃, the set amount of alkali solution is added according to the pH requirement of 7.5-8.0. Finally, the reducing agent is added. After the reaction is completed, the material is discharged and the stirring is turned off.

[0037] The yield and other properties of the silver powder in Examples 1-3 and Comparative Examples 1-3 are shown in the table below:

[0038] As shown in the table above, the silver powder prepared by the multi-reactor synergistic process of this invention has a narrower particle size distribution range and significantly better particle size uniformity than the traditional single-reactor process. The product of this invention has higher loose density and tap density, and better powder packing performance. The multi-reactor closed-loop control of this invention can effectively improve the dispersibility of silver powder, while the product of the traditional single-reactor process is prone to agglomeration and poor dispersibility. With the gradient adjustment of process parameters, this invention can stably prepare silver powder with different particle size specifications, and has a wider range of applications.

[0039] This invention is not limited to the specific embodiments described above. It should be noted that those skilled in the art can make several improvements and substitutions without departing from the technical principles of this invention, and these improvements and substitutions should also be considered within the scope of protection of this invention.

Claims

1. A particle size controllable reduction system based on multi-reactor, multi-parameter regulation, characterized in that, The particle size controllable reduction system includes multiple parallel reduction vessels and a mixing vessel; the number of reduction vessels and the required silver powder particle size distribution in each reduction vessel are determined based on the particle size distribution requirements of the silver powder product; and the reaction conditions for each reduction vessel are determined based on the required silver powder particle size distribution in each reduction vessel. The reaction raw materials in each reduction reactor are the same, and the mass ratio is: silver nitrate: total alkali solution: total reducing agent = 800-850: 120-150: 536-600; The reaction temperature of the reduction vessel is 22℃~85℃. The reaction temperature range for each reduction vessel is determined within this range based on the desired silver powder particle size distribution. Different heating rates are used depending on the desired silver powder particle size distribution for each reduction vessel. For silver powder with a small particle size of D50 of 0.02~0.05μm, the heating rate is 0.5~1.0℃ / min; For medium-sized silver powder with a D50 of 0.05~0.10μm, the heating rate is 1.0~1.5℃ / min; For large-particle-size silver powder with a D50 of 0.10~0.20μm, the heating rate is 1.5~2.5℃ / min; The corresponding heating power is determined based on different heating rates; The pH range of reduction degree is determined based on the different silver powder particle sizes required to be formed in each reduction reactor. Each reduction vessel is connected to the reactants via an independent material delivery pipeline; Each reduction vessel is an independent reaction and control unit, equipped with complete online monitoring components and precise execution components; among them, The complete online detection component includes an online pH electrode, a temperature sensor, and a heating power acquisition module, which are used to collect the pH value, temperature, and actual output power of the heating component in the reaction system in real time. The precise execution components include an alkali metering pump, a jacketed heating assembly, a cooling water solenoid valve, a variable frequency magnetic stirrer, and a flow control valve. The system relies on a complete online detection component to collect parameters of the reaction system inside the reactor in real time and feed them back to the corresponding independent control unit. After comparing them with the preset values, it outputs adjustment commands. The alkali metering pump, heating / cooling components, stirrer and flow control valve operate synchronously to dynamically correct pH value, temperature, power and feed rate, forming a closed-loop control and realizing automatic adjustment of various process parameters. The mixing vessel is used to feed silver powder slurries of different particle sizes formed after the reaction in each reduction vessel into the mixing vessel and mix them for a predetermined time. After washing, dispersing, drying, and passing the inspection, the silver powder product is obtained.

2. A particle size controllable reduction method based on multi-reactor, multi-parameter regulation, implemented by the particle size controllable reduction system described in claim 1, characterized in that, The method includes the following steps: Step 1: Preheat the silver nitrate solution, alkaline solution, and reducing agent solution to the predetermined temperature for later use; Step 2: Add a predetermined amount of silver nitrate solution to each reduction vessel, set the heating power of each reduction vessel, and control its jacketed heating component to heat the silver nitrate solution in the reduction vessel to the required temperature value. The solution in the reduction vessel was stirred using a variable frequency magnetic stirrer. According to the preset pH value requirements of each reduction vessel, alkali solution is added into the reduction vessel through an alkali metering pump; a preset amount of reducing agent is added into the reduction vessel through a flow regulating valve; the pH value, temperature and actual output power of the reaction system in the vessel are collected in real time through an online pH electrode, temperature sensor and heating power acquisition module; the amount of alkali solution and reducing agent added is adjusted accordingly based on the detection data; and silver powder slurry is generated for each reduction vessel. Step 3: Input the silver powder slurry generated from each reduction vessel into the mixing vessel and mix for a predetermined time; then wash, disperse, dry, and test to obtain the silver powder product.

3. The particle size controllable reduction method as described in claim 2, characterized in that, The temperatures of the silver solution, alkaline solution, and reducing agent are controlled at 20~60℃, 20~40℃, and 20~40℃, respectively.

4. The particle size controllable reduction method as described in claim 2, characterized in that, The alkali solution feed rate is 10~50 mL / min.

5. The particle size controllable reduction method as described in claim 2, characterized in that, The silver solution is a silver nitrate solution.

6. The particle size controllable reduction method as described in claim 2, characterized in that, The alkali is one or more of sodium carbonate, sodium hydroxide, and ammonia water, and the total alkali concentration is 30% to 50%.

7. The particle size controllable reduction method as described in claim 2, characterized in that, The reducing agent is one or more of triethanolamine, polyvinyl alcohol, hydrazine hydrate, and polyvinylpyrrolidone, with a concentration of 20% to 40%.

8. The particle size controllable reduction method as described in claim 2, characterized in that, The reaction temperature range is determined based on the different silver powder particle sizes required to be formed in each reduction vessel. The reaction temperature range can be: 22~25℃, 26~30℃, 31~35℃, 36~40℃, ..., or 81~85℃.

9. The particle size controllable reduction method as described in claim 2, characterized in that, The pH range of reduction is determined based on the different silver powder particle sizes required to be formed in each reduction vessel. The pH range of reduction can be: 7.5~7.8, 7.8~8.1, 8.1~8.4, 8.4~8.7, ..., 12.3~12.6, or 12.6~13.

0.

10. The particle size controllable reduction method as described in claim 2, characterized in that, The heating power is determined based on the different silver powder particle sizes required to be formed in each reduction vessel. The heating power can be: 10KW, 12KW, 13KW, 14KW, ..., or 50KW.

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