CN113385678A - Preparation method of nano silver powder with high sintering activity - Google Patents
Preparation method of nano silver powder with high sintering activity Download PDFInfo
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- CN113385678A CN113385678A CN202110660004.2A CN202110660004A CN113385678A CN 113385678 A CN113385678 A CN 113385678A CN 202110660004 A CN202110660004 A CN 202110660004A CN 113385678 A CN113385678 A CN 113385678A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/10—Sintering only
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
- B22F2009/041—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling by mechanical alloying, e.g. blending, milling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2301/00—Metallic composition of the powder or its coating
- B22F2301/25—Noble metals, i.e. Ag Au, Ir, Os, Pd, Pt, Rh, Ru
- B22F2301/255—Silver or gold
Abstract
The invention relates to a preparation method of nano silver powder with high sintering activity, which comprises the following steps of S1, injecting nano silver into a first grinding device through a feed inlet of the first grinding device for primary grinding; step S2, injecting the primarily ground nano silver into a second grinding device through a feed inlet of the second grinding device, grinding the nano silver by high-pressure airflow again, and injecting the nano silver with the particle size into a sintering device through a discharge outlet of the second grinding device; and step S3, the central control unit controls the sintering device to sinter the nano silver. According to the method, the central control unit is arranged, the produced sintered nano silver meets the preset standard according to the obtained failure rate of the nano silver particle size, the volume change rate during sintering, the sintering temperature and the sintering time, and the jet flow frequency, the grinding time of the first grinding device and the power parameters of the power device are adjusted simultaneously, so that the particle size of the love nano silver meets the preset standard.
Description
Technical Field
The invention relates to the field of nano silver preparation, in particular to a method for preparing nano silver powder with high sintering activity.
Background
In the field of microelectronic packaging, third-generation semiconductor materials represented by SiC and GaN have unique properties such as a large forbidden bandwidth, a high breakdown voltage, a high thermal conductivity, and a good chemical stability, and are favored in photoelectric devices, high-frequency high-power, high-temperature electronic devices, and the like, and in the field of printed electronics, ink printing technology has been widely applied in many fields such as solar cells 111121, organic leds ii31, organic thin film transistors 1141, and wearable electronic devices 1151. In recent years, the application of nano-silver particles in the technical field of microelectronic packaging or printed electronics has been researched more, and as a novel green leadless connecting material, nano-silver has good mechanical properties, electric conductivity and heat conductivity, and high working temperature, and can overcome the defect of traditional solder interconnection.
Disclosure of Invention
Therefore, the invention provides a method for preparing nano silver powder with high sintering activity, which can solve the technical problem that the properties of the sintered nano silver cannot be stabilized by controlling the particle size of the nano silver.
In order to achieve the above object, the present invention provides a method for preparing a silver nanoparticle powder with high sintering activity, comprising:
step S1, injecting nano silver into a first grinding device through a feed inlet of the first grinding device for primary grinding;
step S2, injecting the primarily ground nano silver into a second grinding device through a feed inlet of the second grinding device, grinding the nano silver again by high-pressure airflow in the second grinding device, and injecting the nano silver with the particle size into a sintering device through a discharge outlet of the second grinding device;
step S3, the central control unit controls the sintering device to sinter the nano silver;
the second grinding device is provided with an injection supercharging device and is used for grinding the primarily ground nano silver to a preset particle size, the bottom of the second grinding chamber is provided with a detection device and is used for acquiring the weight of the nano silver settled at the bottom of the second grinding chamber, after a first preset time, the central control unit sets the ratio of the weight of the silver powder settled at the bottom of the second grinding chamber to the initial weight as the unqualified rate of the particle size of the silver powder, when the unqualified rate of the particle size acquired by the central control unit is larger than the preset value, the central control unit increases the jet frequency of the injection supercharging device, and when the unqualified rate of the particle size acquired by the central control unit is smaller than the preset value, the central control unit reduces the jet frequency of the injection supercharging device;
the top of the sintering device is provided with a waste gas injection supercharging device which is connected with the injection supercharging device and used for recovering sintering generated gas and applying the recovered gas to secondary grinding of nano silver, an image acquisition device is also arranged in the sintering device and used for acquiring the volume of the nano silver in the sintering process, after a second preset time, the central control unit compares the sintering temperature and the sintering time of the sintering device according to the acquired sintering volume change rate of the nano silver with a preset value and adjusts the sintering temperature and the sintering time of the sintering device, the sintering volume change rate of the nano silver acquired by the central control unit is greater than the preset value, the central control unit reduces the sintering temperature of the sintering device and shortens the sintering time so as to enable nano silver products produced by sintering to meet the preset standard, the sintering volume change rate of the nano silver acquired by the central control unit is less than the preset value, and the central control unit increases the sintering temperature and prolongs, so that the nano silver product produced by sintering meets the preset standard; when the central control unit obtains the sintering real-time temperature, if the sintering real-time temperature is lower than a preset value, the central control unit reduces the jet flow frequency in the second grinding device, and if the sintering real-time temperature is higher than the preset value, the central control unit increases the jet flow frequency of the second grinding device to fully grind the nano silver in the second grinding device so that the particle size of the next nano silver meets a preset standard;
the first grinding device comprises a first grinding chamber and a second grinding chamber, a plurality of grinding mechanisms are arranged in the first grinding chamber and the second grinding chamber and used for grinding nano silver, a connecting device is arranged between the first grinding chamber and the second grinding chamber and used for transmitting the nano silver between the first grinding chamber and the second grinding chamber, a first power device is arranged at the top of the first grinding chamber and used for providing power for grinding of the grinding mechanisms in the first grinding chamber, a second power device is arranged at the bottom of the second grinding chamber and used for providing power for grinding of the grinding mechanisms in the second grinding chamber, when the jet flow frequency acquired by the central control unit is larger than a preset value, the power parameters of the first power device and the second power device are increased by the central control unit, when the jet flow frequency acquired by the central control unit is smaller than the preset value, the power parameters of the first power device and the second power device are reduced by the central control unit, so that the produced nano silver product meets the preset standard.
Further, the central control unit obtains the initial weight m0 of the nano-silver at the beginning of the grinding by the second grinding device, and after a first preset time t1, the central control unit obtains the weight m1 of the nano-silver settled at the bottom of the second grinding device through the detection device, and the ratio of the weight m1 of the nano-silver settled at the bottom of the second grinding device to the initial weight m0 of the nano-silver at the beginning of the grinding by the second grinding device is preset as a fraction m of the fraction defective of the particle size, and is set as m1/m0, wherein,
when M is less than or equal to M1, the central control unit judges that the reject ratio of the current particle size meets the preset standard;
when M1 is more than M and less than M2, the central control unit increases the jet flow frequency P of the injection supercharging device to P1, and sets P1 to P x (1+ (M-M2)/M2);
when M is larger than or equal to M2, the central control unit prolongs the grinding time D of the first grinding device to D1 and sets D1 to Dx (1+ (M1-M)/M1);
the center control unit is preset with a particle size failure rate M, and is set with a first preset particle size failure rate M1 and a second preset particle size failure rate M2.
Further, the central control unit obtains an initial volume V0 of the nano silver at an initial time in the sintering device through the image acquisition device, and after a second preset time t2, the central control unit obtains a volume V1 of the nano silver, sets a rate of change V of the sintering volume of the nano silver, and sets V ═ V0-V1/V0, wherein,
when V is less than or equal to QWi, the central control unit increases the sintering temperature Ti to Ti1 and prolongs the sintering time Si to Si 1;
when V is larger than QWi, the central control unit reduces the sintering temperature Ti to Ti2, sets Ti2 and shortens the sintering time Si to Si 2;
wherein, the central control unit presets sintering stages W, wherein, a first preset sintering stage W1(T1, S1, QW1), a second preset sintering stage W2(T2, S2, QW2), is set, the first preset sintering temperature is T1, the first preset sintering stage sintering time S1, the first preset sintering stage volume change rate standard value is QW1, is set, the second preset sintering temperature is T2, the second preset sintering time is S2, the second preset sintering stage volume change rate standard value is QW2, if the second preset time T2 is in the first preset sintering time, the central control unit selects the first preset sintering temperature T1 as the current sintering temperature, the first preset sintering stage sintering time S1 as the current sintering time, and the first preset sintering time volume change rate standard value is QW1, if the second preset time T2 is the second preset sintering time, the central control unit selects the second preset sintering temperature T2 as the current sintering temperature, selects the second preset sintering time S2 as the current sintering time, and selects the second preset sintering volume change rate standard value QW2 as the evaluation standard of the volume change rate.
Further, when the central control unit obtains that the real-time volume change rate of nano-silver sintering is less than or equal to the selected ith preset sintering time volume change rate standard value QWi, wherein i is 1,2, the central control unit increases the current sintering temperature Ti to Ti1 so that the current nano-silver sintering meets the preset standard, and sets Ti1 to Ti x (1+ (QWi-V)2QWi); the central control unit prolongs the current sintering time Si to Si1 so as to ensure that the sintering in the current sintering stage is sufficient, and the central control unit is set to Si1 ═ Si x (1+ (QWi-V)2/QWi)。
Further, when the central control unit obtains that the real-time volume change rate of nano-silver sintering is greater than the selected ith preset sintering time volume change rate standard value QWi, wherein i is 1,2, the central control unit reduces the current sintering temperature Ti to Ti2, so that the current nano-silver sintering meets the preset standard, and sets Ti2 to Ti x (1- (V-QWi)/QWi); the central control unit shortens the current sintering time Si to Si2 to make the current sintering stage fully sintered, set to Si2 ═ Si × (1+ (V-QWi)/QWi).
Furthermore, the central control unit presets a standard sintering temperature value Ti0, and adjusts the jet flow frequency of the injection supercharging device according to the comparison between the adjusted sintering temperature and the standard sintering temperature value, wherein,
when Tiq is less than Ti0, the central control unit reduces the jet flow frequency P1 to P11 of the injection supercharging device, and sets P11 to P1 x (1- (Ti0-Tiq)/Ti 0);
when Tiq is more than Ti0, the central control unit increases the jet flow frequency P1 to P12 of the injection supercharging device, and sets P12 to P1 x (1+ (Tiq-Ti0)/Ti 0);
the central control unit presets a first preset sintering stage sintering temperature standard value T10 and a second preset sintering stage sintering temperature standard value T20, wherein i is 1,2, and q is 1, 2.
Further, the central control unit presets a jet flow frequency standard value P0, the central control unit adjusts the power parameters of the first power device and the second power device according to the comparison between the adjusted jet flow frequency and the standard value, wherein,
when Pbj is larger than or equal to P0, the central control unit increases the first power device power parameters F1 to F11, sets F11 to F1 multiplied by Pbj/P0, increases the second power device power parameters F2 to F21, and sets F21 to F2 multiplied by Pbj/P0;
when Pbj < P0, the central control unit decreases the first power plant power parameters F1 to F12, sets F12 to F1 × Pbj/P0, decreases the second power plant power parameters F2 to F22, sets F22 to F2 × Pbj/P0;
wherein, b is 1,2, j is 1, 2.
Further, when the central control unit increases the power parameter of the ith power plant, the central control unit decreases the rotation speed Li to Li1 of the ith grinding chamber grinding mechanism, sets Li1 to Li x (1- (Far-Fa)/Fa), and simultaneously extends the grinding time D1 to D11 of the first grinding device, sets D11 to D1 x (1+ (Far-Fa)/Fa), and the central control unit presets the rotation speed L1 of the first grinding chamber grinding mechanism and the rotation speed L2 of the second grinding chamber grinding mechanism, wherein a is 1,2, and r is 1, 2.
Further, when the central control unit reduces the power parameter of the ith power device, the central control unit increases the rotation speed Li to Li2 of the grinding mechanism of the ith grinding chamber, sets Li2 to Li x (1- (Fa-Far)/Fa), and simultaneously shortens the grinding time D1 to D12 of the first grinding device, sets D12 to D1 x (1+ (Fa-Far)/Fa).
Compared with the prior art, the injection supercharging device has the beneficial effects that the central control unit is arranged, according to the obtained nano-silver particle size fraction defective, when the particle size fraction defective obtained by the central control unit is larger than a preset value, the jet frequency of the injection supercharging device is increased by the central control unit, and when the particle size fraction defective obtained by the central control unit is smaller than the preset value, the jet frequency of the injection supercharging device is reduced by the central control unit; the central control unit is used for adjusting the sintering temperature and the sintering time of the sintering device according to the comparison between the obtained nano-silver sintering volume change rate and a preset value, the nano-silver sintering volume change rate obtained by the central control unit is larger than the preset value, the central control unit is used for reducing the sintering temperature of the sintering device and shortening the sintering time so that the nano-silver product produced by sintering meets the preset standard, the nano-silver sintering volume change rate obtained by the central control unit is smaller than the preset value, and the central control unit is used for increasing the sintering temperature and prolonging the sintering time so that the nano-silver product produced by sintering meets the preset standard; when the central control unit obtains the sintering real-time temperature, if the sintering real-time temperature is lower than a preset value, the central control unit reduces the jet flow frequency in the second grinding device, and if the sintering real-time temperature is higher than the preset value, the central control unit increases the jet flow frequency of the second grinding device to fully grind the nano silver in the second grinding device so that the particle size of the next nano silver meets a preset standard; and when the jet flow frequency acquired by the central control unit is greater than the preset value, the central control unit increases the power parameters of the first power device and the second power device, and when the jet flow frequency acquired by the central control unit is less than the preset value, the central control unit reduces the power parameters of the first power device and the second power device, so that the produced nano silver product meets the preset standard.
Particularly, the invention takes the ratio of the weight of the nano silver which does not meet the preset grain size standard within the preset time to the initial weight as the grain size failure rate, the invention compares the obtained grain size failure rate with the preset value, when the obtained grain size failure rate is less than or equal to the first preset grain size failure rate, the nano silver which is put into the second grinding device is ground for the preset time, the produced nano silver with qualified grain size meets the preset standard, the central control unit does not adjust various parameters, when the obtained grain size failure rate is between the first preset grain size failure rate and the second preset grain size failure rate, the second grinding device is not sufficiently ground, the central control unit increases the jet frequency of the second grinding device to improve the grinding degree, when the obtained grain size failure rate is more than or equal to the second preset grain size failure rate, the grain size of the nano silver which is put into the second grinding device does not meet the preset standard, the second grinder can not grind the nano-silver to a preset particle size through grinding for a preset time, and the primary grinding process is more sufficient by the central control unit through prolonging the grinding time of the first grinder, so that the nano-silver particle size entering the second grinder is smaller, and the grinding efficiency of the second grinder is improved.
Particularly, the invention sets the temperature, time and volume change rate of the first sintering stage and the second sintering stage, and the central control unit sinters the nano silver according to the preset sintering time and sintering temperature, wherein, the central control unit compares the obtained sintering volume change rate of the nano silver with the preset volume change rate of the sintering stage, if the sintering volume change rate is less than or equal to the preset volume change rate of the sintering stage, the preset temperature and time of the sintering stage are not matched with the sintering state of the nano silver, and the sintering degree is poorer, therefore, the central control unit greatly increases the sintering temperature of the sintering stage and prolongs the sintering time according to the square of the difference value of the volume change rate and the preset value as a reference, so that the produced sintering nano silver meets the preset standard, if the sintering volume change rate is greater than the preset volume change rate of the sintering stage, the preset sintering temperature and the preset sintering time of the sintering stage cause the sintering efficiency of the nano silver to be too fast, the sintering efficiency is too high, so that the nano silver sintered product is not uniformly sintered, the performance of the sintered nano silver product is influenced, and the central control unit reduces the current sintering temperature and shortens the sintering time in a smaller range according to the difference value between the volume change rate and the preset value, so that the nano silver sintering efficiency is reduced.
Particularly, the invention sets the temperature, time and volume change rate of the first sintering stage and the second sintering stage, and the central control unit sinters the nano silver according to the preset sintering time and sintering temperature, wherein, the central control unit compares the obtained sintering volume change rate of the nano silver with the preset volume change rate of the sintering stage, if the sintering volume change rate is less than or equal to the preset volume change rate of the sintering stage, the preset temperature and time of the sintering stage are not matched with the sintering state of the nano silver, and the sintering degree is poorer, therefore, the central control unit greatly increases the sintering temperature of the sintering stage and prolongs the sintering time according to the square of the difference value of the volume change rate and the preset value as a reference, so that the produced sintering nano silver meets the preset standard, if the sintering volume change rate is greater than the preset volume change rate of the sintering stage, the preset sintering temperature and the preset sintering time of the sintering stage cause the sintering efficiency of the nano silver to be too fast, the sintering efficiency is too high, so that the nano silver sintered product is not uniformly sintered, the performance of the sintered nano silver product is influenced, and the central control unit reduces the current sintering temperature and shortens the sintering time in a smaller range according to the difference value between the volume change rate and the preset value, so that the nano silver sintering efficiency is reduced.
Particularly, the sintering temperature standard value of each sintering stage is preset by the central control unit, the jet flow frequency of the injection supercharging device is adjusted according to the comparison between the adjusted sintering temperature and the sintering temperature standard value, when the adjusted sintering temperature is higher than the sintering temperature standard value of the sintering stage, the current nano silver particle size does not accord with the preset standard, and the central control unit increases the jet flow frequency of the second grinding device so that the particle size of the next nano silver entering the sintering device accords with the preset standard; when the adjusted sintering temperature is smaller than the sintering temperature standard value in the sintering stage, which indicates that the particle size of the current nano-silver does not meet the preset standard, the central control unit reduces the jet flow frequency of the second grinding device so that the particle size of the next nano-silver entering the sintering device meets the preset standard.
Particularly, the invention sets a jet flow frequency standard value, the central control unit compares the acquired adjusted jet flow frequency with the standard value to adjust the power parameters of the first power device and the second power device, wherein if the adjusted jet flow frequency is more than or equal to the preset standard value, the central control unit increases the friction force of the grinding mechanism by increasing the power parameters of the first power device and the second power device to ensure that the nano silver entering the second grinding device meets the preset standard, the further grinding of the nano silver is fully carried out, if the adjusted jet flow frequency is less than the preset standard value, the central control unit reduces the friction force of the grinding mechanism by reducing the power parameters of the first power device and the second power device to avoid the particle diameter of the nano silver entering the second grinding device from being too small, resulting in final over-sintering.
Particularly, the rotation speed and the grinding time of the grinding mechanism of the first grinding device are adjusted while the central control unit obtains the adjustment of increasing or decreasing of each power device, wherein when the central control unit judges that power parameters of the power devices need to be increased, the central control unit further grinds the nano silver more fully by reducing the rotation speed of the grinding mechanism and prolonging the grinding time of the first grinding device, and when the central control unit judges that power parameters of the power devices need to be increased, the central control unit improves the rotation speed of the grinding mechanism and shortens the grinding time of the first grinding device, so that the grain diameter of the ground nano silver meets a preset standard, and the excessive later sintering is avoided.
Drawings
FIG. 1 is a schematic diagram of a method for preparing nano silver powder with high sintering activity according to an embodiment of the invention;
FIG. 2 is a schematic structural diagram of a nano-silver preparation device with high sintering activity according to an embodiment of the invention;
FIG. 3 is a schematic view of a first polishing apparatus according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a second polishing apparatus according to an embodiment of the present invention.
Detailed Description
In order that the objects and advantages of the invention will be more clearly understood, the invention is further described below with reference to examples; it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and do not limit the scope of the present invention.
It should be noted that in the description of the present invention, the terms of direction or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, which are only for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.
Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
Referring to fig. 1, a method for preparing nano silver powder with high sintering activity according to an embodiment of the present invention includes,
step S1, injecting nano silver into a first grinding device through a feed inlet of the first grinding device for primary grinding;
step S2, injecting the primarily ground nano silver into a second grinding device through a feed inlet of the second grinding device, grinding the nano silver again by high-pressure airflow in the second grinding device, and injecting the nano silver with the particle size into a sintering device through a discharge outlet of the second grinding device;
step S3, the central control unit controls the sintering device to sinter the nano silver;
the second grinding device is provided with an injection supercharging device and is used for grinding the primarily ground nano silver to a preset particle size, the bottom of the second grinding chamber is provided with a detection device and is used for acquiring the weight of the nano silver settled at the bottom of the second grinding chamber, after a first preset time, the central control unit sets the ratio of the weight of the silver powder settled at the bottom of the second grinding chamber to the initial weight as the unqualified rate of the particle size of the silver powder, when the unqualified rate of the particle size acquired by the central control unit is larger than the preset value, the central control unit increases the jet frequency of the injection supercharging device, and when the unqualified rate of the particle size acquired by the central control unit is smaller than the preset value, the central control unit reduces the jet frequency of the injection supercharging device;
the top of the sintering device is provided with a waste gas injection supercharging device which is connected with the injection supercharging device and used for recovering sintering generated gas and applying the recovered gas to secondary grinding of nano silver, an image acquisition device is also arranged in the sintering device and used for acquiring the volume of the nano silver in the sintering process, after a second preset time, the central control unit compares the sintering temperature and the sintering time of the sintering device according to the acquired sintering volume change rate of the nano silver with a preset value and adjusts the sintering temperature and the sintering time of the sintering device, the sintering volume change rate of the nano silver acquired by the central control unit is greater than the preset value, the central control unit reduces the sintering temperature of the sintering device and shortens the sintering time so as to enable nano silver products produced by sintering to meet the preset standard, the sintering volume change rate of the nano silver acquired by the central control unit is less than the preset value, and the central control unit increases the sintering temperature and prolongs the sintering time, so that the nano silver product produced by sintering meets the preset standard; when the central control unit obtains the sintering real-time temperature, if the sintering real-time temperature is lower than a preset value, the central control unit reduces the jet flow frequency in the second grinding device, and if the sintering real-time temperature is higher than the preset value, the central control unit increases the jet flow frequency of the second grinding device to fully grind the nano silver in the second grinding device so that the particle size of the next nano silver meets a preset standard;
the first grinding device comprises a first grinding chamber and a second grinding chamber, a plurality of grinding mechanisms are arranged in the first grinding chamber and the second grinding chamber and used for grinding nano silver, a connecting device is arranged between the first grinding chamber and the second grinding chamber and used for transmitting the nano silver between the first grinding chamber and the second grinding chamber, a first power device is arranged at the top of the first grinding chamber and used for providing power for grinding of the grinding mechanisms in the first grinding chamber, a second power device is arranged at the bottom of the second grinding chamber and used for providing power for grinding of the grinding mechanisms in the second grinding chamber, when the jet flow frequency acquired by the central control unit is larger than a preset value, the power parameters of the first power device and the second power device are increased by the central control unit, when the jet flow frequency acquired by the central control unit is smaller than the preset value, the power parameters of the first power device and the second power device are reduced by the central control unit, so that the produced nano silver product meets the preset standard.
Please refer to fig. 2, which is a schematic structural diagram of a nano-silver preparation apparatus with high sintering activity according to an embodiment of the present invention, including a first grinding device 1 for primarily grinding the injected nano-silver, the first grinding device being connected to a second grinding device 2, the second grinding device being used for grinding the primarily ground nano-silver again to a predetermined particle size, a sintering device 3 connected to the second grinding device for sintering the secondarily ground nano-silver, and a gas recovery device 31 being disposed at the top of the sintering device for recovering hot gas generated by sintering.
Referring to fig. 3, which is a schematic structural diagram of a first grinding device according to an embodiment of the present invention, the first grinding device includes a first grinding chamber, the first grinding chamber includes a first grinding mechanism 104, a first gear 103 is installed at one side of the first grinding mechanism for driving the first grinding mechanism to rotate, a second grinding mechanism 107 is installed below the first grinding mechanism, a second gear 106 is installed at one side of the second grinding mechanism for driving the second grinding mechanism to rotate, a first vertical gear 105 is installed between the first gear and the second gear, the first vertical gear is used for changing the rotation direction of the first gear and the second gear, a third grinding mechanism 110 is installed below the second grinding mechanism, a third gear 109 is installed at one side of the third grinding mechanism for rotating the third grinding mechanism, and a second vertical gear 108 is installed between the third gear and the second gear, for changing the rotation direction of the second grinding mechanism and the second grinding mechanism, the third gear is connected with a first gear power device 123, and the first gear power device is used for providing power for the rotation of the third gear.
With reference to fig. 3, the first grinding device includes a second grinding chamber, the second grinding chamber includes a fourth grinding mechanism 114, a fourth gear 115 is disposed on one side of the fourth grinding mechanism for driving the fourth grinding mechanism to rotate, a fifth grinding mechanism 121 is disposed below the fourth grinding mechanism, a fifth gear 117 is disposed on one side of the fifth grinding mechanism for driving the fifth grinding mechanism to rotate, a third vertical gear 116 is disposed between the fourth gear and the fifth gear for changing the rotation direction of the fourth grinding mechanism and the fifth grinding mechanism, a sixth grinding mechanism 122 is disposed below the fifth grinding mechanism, a sixth gear 119 is disposed on one side of the sixth grinding mechanism for driving the sixth grinding mechanism to rotate, the fifth gear and the sixth gear are connected through the fourth vertical gear, and the fourth vertical gear is used for changing the rotation of the fifth grinding mechanism and the sixth grinding mechanism, the sixth gear is connected to a second gear power means 124 for powering the rotation of the gears.
A first connecting plate 113 is arranged between the first grinding mechanism and the fourth grinding mechanism and used for transmitting the nano silver of the first grinding mechanism to the fourth grinding mechanism, a second connecting plate 111 is arranged between the fourth grinding mechanism and the second grinding mechanism and used for transmitting the nano silver of the fourth grinding mechanism to the second grinding mechanism, and a third connecting plate 112 is arranged between the third grinding mechanism and the sixth grinding mechanism and used for transmitting the nano silver of the third grinding mechanism to the sixth grinding mechanism; in use, nano silver is injected into the first grinding chamber through the feed inlet 102, the nano silver is ground in the first grinding mechanism and the second grinding mechanism and is transmitted to the fourth grinding mechanism through the first connecting plate, the nano silver is ground again in the fourth grinding mechanism and the fifth grinding mechanism, the ground nano silver is transmitted to the second grinding mechanism through the second connecting plate, the nano silver is transmitted to the sixth grinding mechanism through the third connecting plate after being ground by the second grinding mechanism and the third grinding mechanism, the nano silver is ground in the sixth grinding mechanism and the fifth grinding mechanism, and the ground nano silver is output through the discharge outlet 120.
The top of the first grinding chamber is provided with a first power device 101, the first power device is used for providing downward power for the grinding mechanism in the first grinding chamber, the first power device is connected with the first grinding mechanism through a first power device connecting shaft, the bottom of the second grinding chamber is provided with a second power device 125, and the second power device is used for providing upward power for the grinding mechanism in the second grinding chamber, and the second power device is connected with the sixth grinding mechanism through a second power device connecting shaft.
In use, the first power device provides downward power for the grinding mechanism of the first grinding chamber, the first grinding mechanism, the second grinding mechanism and the third grinding mechanism are in closer contact, the friction force between the grinding mechanism and the nano-silver is increased when the first grinding mechanism, the second grinding mechanism and the third grinding mechanism rotate, the second power device provides upward power for the grinding mechanism of the second grinding chamber, the fourth grinding mechanism, the fifth grinding mechanism and the sixth grinding mechanism are in closer contact, and the friction force between the grinding mechanism and the nano-silver is increased when the second grinding mechanism rotates.
In use, taking the first grinding chamber as an example, the first gear power device drives the third gear to rotate, the third gear drives the third grinding mechanism to rotate, the third gear drives the second vertical gear to rotate, the second vertical gear drives the second gear to rotate in a direction opposite to the rotation direction of the third gear, and further drives the second grinding mechanism to rotate in a direction opposite to the rotation direction, the second gear rotates to drive the first vertical gear to rotate, the first vertical gear drives the first gear to rotate in a direction opposite to the rotation direction of the second gear, so that the rotation directions of the first grinding mechanism and the third grinding mechanism are consistent, the rotation direction of the second grinding mechanism is opposite to the rotation directions of the first grinding mechanism and the second grinding mechanism, when the first grinding mechanism is filled with nano silver, the central control unit controls the first power device to provide power for the grinding mechanism in the first grinding chamber, the rotation directions of adjacent grinding mechanisms are opposite, the grinding of the nano silver is realized.
Please refer to fig. 4, which is a schematic structural diagram of a second grinding device according to an embodiment of the present invention, including a third grinding chamber, the top of the third grinding chamber is provided with an injection supercharging device 201 for converting hot gas generated by sintering into high-speed airflow of the injection supercharging device, the injection supercharging device includes a first injection supercharging pipe 203 and a second injection supercharging pipe 215, the first injection supercharging pipe and the second injection supercharging pipe are used for transmitting the high-speed airflow, two sides of the third grinding chamber are provided with a first grinding block 205 and a second grinding block 214 for grinding nano silver, the first injection supercharging pipe is provided with a first jet nozzle 209 and a second jet nozzle 210, wherein the first jet nozzle and the second jet nozzle pass through the first grinding block, the first jet nozzle is located above the second jet nozzle, the second injection supercharging pipe is provided with a third jet nozzle 211 and a fourth jet nozzle 204, the third jet flow nozzle is arranged above the fourth jet flow nozzle, the third jet flow nozzle and the fourth jet flow nozzle penetrate through the second grinding block, and the jet flow nozzles on the different sides of the third grinding chamber are vertically staggered. The third grinds the room bottom and is provided with breather 208 for blow the nanometer silver that subsides in the third grinds the room bottom to the third and grind indoor inside, breather still includes second breather 202 for blow the nanometer silver that the particle diameter accords with the standard to second grinder discharge gate 213, draw and penetrate supercharging device still includes gas-supply pipe 206 for the steam transmission that produces the sintering is for drawing and penetrate supercharging device.
During use, the nano silver is blown into the third grinding chamber through the air ventilation device, the jet nozzle changes the motion direction of the nano silver by high-speed airflow, the nano silver is rubbed on the grinding block for multiple times to reduce the particle size until the particle size reaches a preset standard, and the particle size which meets the standard is driven by the air pressure of the second air ventilation port to be discharged out of the second grinding device.
Specifically, the method comprises the steps that a central control unit is arranged, according to the obtained nano-silver particle size fraction defective, when the particle size fraction defective obtained by the central control unit is larger than a preset value, the jet flow frequency of the injection supercharging device is increased by the central control unit, and when the particle size fraction defective obtained by the central control unit is smaller than the preset value, the jet flow frequency of the injection supercharging device is reduced by the central control unit; the central control unit is used for adjusting the sintering temperature and the sintering time of the sintering device according to the comparison between the obtained nano-silver sintering volume change rate and a preset value, the nano-silver sintering volume change rate obtained by the central control unit is larger than the preset value, the central control unit is used for reducing the sintering temperature of the sintering device and shortening the sintering time so that the nano-silver product produced by sintering meets the preset standard, the nano-silver sintering volume change rate obtained by the central control unit is smaller than the preset value, and the central control unit is used for increasing the sintering temperature and prolonging the sintering time so that the nano-silver product produced by sintering meets the preset standard; when the central control unit obtains the sintering real-time temperature, if the sintering real-time temperature is lower than a preset value, the central control unit reduces the jet flow frequency in the second grinding device, and if the sintering real-time temperature is higher than the preset value, the central control unit increases the jet flow frequency of the second grinding device to fully grind the nano silver in the second grinding device so that the particle size of the next nano silver meets a preset standard; and when the jet flow frequency acquired by the central control unit is greater than the preset value, the central control unit increases the power parameters of the first power device and the second power device, and when the jet flow frequency acquired by the central control unit is less than the preset value, the central control unit reduces the power parameters of the first power device and the second power device, so that the produced nano silver product meets the preset standard.
The central control unit obtains the initial weight m0 of the nano silver when the second grinding device starts grinding, after a first preset time t1, the central control unit obtains the weight m1 of the silver nano silver settled at the bottom of the second grinding device through the detection device, the ratio of the weight m1 of the nano silver settled at the bottom of the second grinding device to the initial weight m0 of the nano silver when the second grinding device starts grinding is preset as a particle size fraction m, and the setting is that m is m1/m0, wherein,
when M is less than or equal to M1, the central control unit judges that the reject ratio of the current particle size meets the preset standard;
when M1 is more than M and less than M2, the central control unit increases the jet flow frequency P of the injection supercharging device to P1, and sets P1 to P x (1+ (M-M2)/M2);
when M is larger than or equal to M2, the central control unit prolongs the grinding time D of the first grinding device to D1 and sets D1 to Dx (1+ (M1-M)/M1);
the center control unit is preset with a particle size failure rate M, and is set with a first preset particle size failure rate M1 and a second preset particle size failure rate M2.
Specifically, the invention takes the ratio of the weight of the nano-silver which does not meet the preset grain size standard within the preset time to the initial weight as the grain size failure rate, compares the obtained grain size failure rate with the preset value, when the obtained grain size failure rate is less than or equal to the first preset grain size failure rate, the nano-silver which is put into the second grinding device is ground for the preset time, the produced nano-silver with qualified grain size meets the preset standard, the central control unit does not adjust various parameters, when the obtained grain size failure rate is between the first preset grain size failure rate and the second preset grain size failure rate, the second grinding device is not sufficiently ground, the central control unit increases the jet frequency of the second grinding device to improve the grinding degree, when the obtained grain size failure rate is greater than or equal to the second preset grain size failure rate, the grain size of the nano-silver which is put into the second grinding device does not meet the preset standard, the second grinder can not grind the nano-silver to a preset particle size through grinding for a preset time, and the primary grinding process is more sufficient by the central control unit through prolonging the grinding time of the first grinder, so that the nano-silver particle size entering the second grinder is smaller, and the grinding efficiency of the second grinder is improved.
The central control unit obtains an initial volume V0 of the nano silver at an initial time in the sintering device through the image acquisition device, obtains a volume V1 of the nano silver after a second preset time t2, sets a volume change rate V of the nano silver sintering volume, and sets the value V to be (V0-V1)/V0, wherein,
when V is less than or equal to QWi, the central control unit increases the sintering temperature Ti to Ti1 and prolongs the sintering time Si to Si 1;
when V is larger than QWi, the central control unit reduces the sintering temperature Ti to Ti2, sets Ti2 and shortens the sintering time Si to Si 2;
wherein, the central control unit presets sintering stages W, wherein, a first preset sintering stage W1(T1, S1, QW1), a second preset sintering stage W2(T2, S2, QW2), is set, the first preset sintering temperature is T1, the first preset sintering stage sintering time S1, the first preset sintering stage volume change rate standard value is QW1, is set, the second preset sintering temperature is T2, the second preset sintering time is S2, the second preset sintering stage volume change rate standard value is QW2, if the second preset time T2 is in the first preset sintering time, the central control unit selects the first preset sintering temperature T1 as the current sintering temperature, the first preset sintering stage sintering time S1 as the current sintering time, and the first preset sintering time volume change rate standard value is QW1, if the second preset time T2 is the second preset sintering time, the central control unit selects the second preset sintering temperature T2 as the current sintering temperature, selects the second preset sintering time S2 as the current sintering time, and selects the second preset sintering volume change rate standard value QW2 as the evaluation standard of the volume change rate.
Specifically, in the embodiment of the present invention, the first preset sintering temperature T1 in the first preset sintering stage is 200 ℃, the first preset sintering time S1 is 55 minutes, the first preset sintering time volume change rate standard value QW1 is 4.2%, the second preset sintering temperature T2 is 165 ℃, the second preset sintering time S2 is 25 minutes, and the second preset sintering time volume change rate standard value QW2 is 1.5%.
Specifically, the invention sets the temperature, time and volume change rate of the first sintering stage and the second sintering stage, and the central control unit sinters the nano silver according to the preset sintering time and sintering temperature, wherein, the central control unit compares the obtained sintering volume change rate of the nano silver with the preset volume change rate of the sintering stage, if the sintering volume change rate is less than or equal to the preset volume change rate of the sintering stage, the preset temperature and time of the sintering stage are not matched with the sintering state of the nano silver, and the sintering degree is poorer, therefore, the central control unit greatly increases the sintering temperature of the sintering stage and prolongs the sintering time according to the square of the difference value between the volume change rate and the preset value as a reference, so that the produced sintering nano silver meets the preset standard, if the sintering volume change rate is greater than the preset volume change rate of the sintering stage, the preset sintering temperature and the preset sintering time in the sintering stage enable the nano-silver sintering efficiency to be too high, the sintering efficiency is too high, the nano-silver sintered product is not uniformly sintered, the performance of the sintered nano-silver product is affected, and the central control unit reduces the current sintering temperature and shortens the sintering time at the same time according to the difference value between the volume change rate and the preset value and in a small range, so that the nano-silver sintering efficiency is reduced.
When the central control unit obtains the volume change rate of the nano-silver sintering real-time volume change rate less than or equal to the selected ith preset sintering time volume change rate standard value QWi, wherein i is 1,2, the central control unit increases the current sintering temperature Ti to Ti1 so that the current nano-silver sintering meets the preset standard, and sets Ti1 to Ti x (1+ (QWi-V)2QWi); the central control unit prolongs the current sintering time Si to Si1 so as to ensure that the sintering in the current sintering stage is sufficient, and the central control unit is set to Si1 ═ Si x (1+ (QWi-V)2/QWi)。
When the central control unit obtains that the real-time volume change rate of nano-silver sintering is greater than the i-th preset sintering time volume change rate standard value QWi, wherein i is 1,2, the central control unit reduces the current sintering temperature Ti to Ti2 so that the current nano-silver sintering meets the preset standard, and sets Ti2 to be Ti x (1- (V-QWi)/QWi); the central control unit shortens the current sintering time Si to Si2 to make the current sintering stage fully sintered, set to Si2 ═ Si × (1+ (V-QWi)/QWi).
Specifically, the invention sets the temperature, time and volume change rate of the first sintering stage and the second sintering stage, and the central control unit sinters the nano silver according to the preset sintering time and sintering temperature, wherein, the central control unit compares the obtained sintering volume change rate of the nano silver with the preset volume change rate of the sintering stage, if the sintering volume change rate is less than or equal to the preset volume change rate of the sintering stage, the preset temperature and time of the sintering stage are not matched with the sintering state of the nano silver, and the sintering degree is poorer, therefore, the central control unit greatly increases the sintering temperature of the sintering stage and prolongs the sintering time according to the square of the difference value between the volume change rate and the preset value as a reference, so that the produced sintering nano silver meets the preset standard, if the sintering volume change rate is greater than the preset volume change rate of the sintering stage, the preset sintering temperature and the preset sintering time in the sintering stage enable the nano-silver sintering efficiency to be too high, the sintering efficiency is too high, the nano-silver sintered product is not uniformly sintered, the performance of the sintered nano-silver product is affected, and the central control unit reduces the current sintering temperature and shortens the sintering time at the same time according to the difference value between the volume change rate and the preset value and in a small range, so that the nano-silver sintering efficiency is reduced.
The central control unit presets a sintering temperature standard value Ti0, and adjusts the jet flow frequency of the injection supercharging device according to the comparison between the adjusted sintering temperature and the sintering temperature standard value, wherein,
when Tiq is less than Ti0, the central control unit reduces the jet flow frequency P1 to P11 of the injection supercharging device, and sets P11 to P1 x (1- (Ti0-Tiq)/Ti 0);
when Tiq is more than Ti0, the central control unit increases the jet flow frequency P1 to P12 of the injection supercharging device, and sets P12 to P1 x (1+ (Tiq-Ti0)/Ti 0);
the central control unit presets a first preset sintering stage sintering temperature standard value T10 and a second preset sintering stage sintering temperature standard value T20, wherein i is 1,2, and q is 1, 2.
Specifically, the sintering temperature standard value of each sintering stage is preset through the central control unit, the jet flow frequency of the injection supercharging device is adjusted according to the comparison between the adjusted sintering temperature and the sintering temperature standard value, when the adjusted sintering temperature is higher than the sintering temperature standard value of the sintering stage, the current nano silver particle size does not accord with the preset standard, and the central control unit increases the jet flow frequency of the second grinding device so that the particle size of the next nano silver entering the sintering device accords with the preset standard; when the adjusted sintering temperature is smaller than the sintering temperature standard value in the sintering stage, which indicates that the particle size of the current nano-silver does not meet the preset standard, the central control unit reduces the jet flow frequency of the second grinding device so that the particle size of the next nano-silver entering the sintering device meets the preset standard.
The central control unit presets a jet flow frequency standard value P0, and adjusts the power parameters of the first power device and the second power device according to the comparison between the adjusted jet flow frequency and the standard value, wherein,
when Pbj is larger than or equal to P0, the central control unit increases the first power device power parameters F1 to F11, sets F11 to F1 multiplied by Pbj/P0, increases the second power device power parameters F2 to F21, and sets F21 to F2 multiplied by Pbj/P0;
when Pbj < P0, the central control unit decreases the first power plant power parameters F1 to F12, sets F12 to F1 × Pbj/P0, decreases the second power plant power parameters F2 to F22, sets F22 to F2 × Pbj/P0;
wherein, b is 1,2, j is 1, 2.
Specifically, the invention sets a jet flow frequency standard value, the central control unit compares the obtained adjusted jet flow frequency with the standard value, and adjusts the power parameters of the first power device and the second power device, wherein if the adjusted jet flow frequency is more than or equal to a preset standard value, the central control unit increases the friction force of the grinding mechanism by increasing the power parameters of the first power device and the second power device to ensure that the nano silver entering the second grinding device meets the preset standard, further fully grinds the nano silver, if the adjusted jet flow frequency is less than the preset standard value, the central control unit reduces the friction force of the grinding mechanism by reducing the power parameters of the first power device and the second power device to avoid that the particle diameter of the nano silver entering the second grinding device is too small, resulting in final over-sintering.
When the central control unit increases the power parameter of the ith power device, the central control unit reduces the rotation speed Li to Li1 of the grinding mechanism of the ith grinding chamber, sets Li1 to Li x (1- (Far-Fa)/Fa), and simultaneously prolongs the grinding time D1 to D11 of the first grinding device and sets D11 to D1 x (1+ (Far-Fa)/Fa), wherein the central control unit presets the rotation speed L1 of the grinding mechanism of the first grinding chamber and the rotation speed L2 of the second grinding chamber, and a is 1,2, and r is 1, 2.
When the central control unit reduces the power parameter of the ith power device, the central control unit increases the rotation speed Li to Li2 of the grinding mechanism of the ith grinding chamber, sets Li2 to Li x (1- (Fa-Far)/Fa), and simultaneously shortens the grinding time D1 to D12 of the first grinding device, and sets D12 to D1 x (1+ (Fa-Far)/Fa).
Specifically, the rotation speed and the grinding time of the grinding mechanism of the first grinding device are adjusted while the central control unit obtains the adjustment of increasing or decreasing of each power device, wherein when the central control unit judges that power parameters of the power devices need to be increased, the central control unit further grinds the nano silver more fully by reducing the rotation speed of the grinding mechanism and prolonging the grinding time of the first grinding device, and when the central control unit judges that power parameters of the power devices need to be increased, the central control unit improves the rotation speed of the grinding mechanism and shortens the grinding time of the first grinding device, so that the grain diameter of the ground nano silver meets a preset standard, and the excessive later sintering is avoided.
Specifically, the preparation method of the nano silver in the embodiment of the invention comprises the following steps:
step S101, mixing silver nitrate and a quaternary ammonium dispersant to obtain a silver nitrate dispersion solution; step S102, rapidly adding a reducing agent solution into a silver nitrate dispersion solution; step S103, adding an accelerant into the reaction solution, and mixing to obtain a silver powder suspension; step S104, centrifugal separation; step S105, adding the silver powder sample into a rosin ethanol solution, and mixing to obtain nano silver powder slurry; and step S106, drying to obtain the nano silver powder.
Wherein the concentration of silver nitrate in the step S101 is 0.1-2 mol/L, the concentration of a reducing agent in the step S102 is 0.5-4mol/L, the reducing agent is preferably triethanolamine, diethanolamine or ethylene glycol, and the accelerator in the step S103 is hydrogen peroxide, ammonia water or sodium oxysulfide aqueous solution; the step of centrifuging in step S104 is to centrifuge the silver powder suspension after standing, wherein the centrifugation speed is 3000-; then, the crude silver powder is sequentially added into pure water, ethanol water solution (ethanol 70 percent) and absolute ethanol, and the operations of centrifugation (10-120min) at 3000r/min of 1000-;
in particular, the sintered nano silver produced by the embodiment of the invention shows good thermal conductivity and electrical resistivity, so that the sintered nano silver can be applied to the technical field of microelectronic packaging or printed electronics.
So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.
Claims (9)
1. A method for preparing nano silver powder with high sintering activity is characterized by comprising the following steps:
step S1, injecting nano silver into a first grinding device through a feed inlet of the first grinding device for primary grinding;
step S2, injecting the primarily ground nano silver into a second grinding device through a feed inlet of the second grinding device, grinding the nano silver again by high-pressure airflow in the second grinding device, and injecting the nano silver with the particle size into a sintering device through a discharge outlet of the second grinding device;
step S3, the central control unit controls the sintering device to sinter the nano silver;
the second grinding device is provided with an injection supercharging device and is used for grinding the primarily ground nano silver to a preset particle size, the bottom of the second grinding chamber is provided with a detection device and is used for acquiring the weight of the nano silver settled at the bottom of the second grinding chamber, after a first preset time, the central control unit sets the ratio of the weight of the silver powder settled at the bottom of the second grinding chamber to the initial weight as the unqualified rate of the particle size of the silver powder, when the unqualified rate of the particle size acquired by the central control unit is larger than the preset value, the central control unit increases the jet frequency of the injection supercharging device, and when the unqualified rate of the particle size acquired by the central control unit is smaller than the preset value, the central control unit reduces the jet frequency of the injection supercharging device;
the top of the sintering device is provided with a waste gas injection supercharging device which is connected with the injection supercharging device and used for recovering sintering generated gas and applying the recovered gas to secondary grinding of nano silver, an image acquisition device is also arranged in the sintering device and used for acquiring the volume of the nano silver in the sintering process, after a second preset time, the central control unit compares the sintering temperature and the sintering time of the sintering device according to the acquired sintering volume change rate of the nano silver with a preset value and adjusts the sintering temperature and the sintering time of the sintering device, the sintering volume change rate of the nano silver acquired by the central control unit is greater than the preset value, the central control unit reduces the sintering temperature of the sintering device and shortens the sintering time so as to enable nano silver products produced by sintering to meet the preset standard, the sintering volume change rate of the nano silver acquired by the central control unit is less than the preset value, and the central control unit increases the sintering temperature and prolongs the sintering time, so that the nano silver product produced by sintering meets the preset standard; when the central control unit obtains the sintering real-time temperature, if the sintering real-time temperature is lower than a preset value, the central control unit reduces the jet flow frequency in the second grinding device, and if the sintering real-time temperature is higher than the preset value, the central control unit increases the jet flow frequency of the second grinding device to fully grind the nano silver in the second grinding device so that the particle size of the next nano silver meets a preset standard;
the first grinding device comprises a first grinding chamber and a second grinding chamber, a plurality of grinding mechanisms are arranged in the first grinding chamber and the second grinding chamber and used for grinding nano silver, a connecting device is arranged between the first grinding chamber and the second grinding chamber and used for transmitting the nano silver between the first grinding chamber and the second grinding chamber, a first power device is arranged at the top of the first grinding chamber and used for providing power for grinding of the grinding mechanisms in the first grinding chamber, a second power device is arranged at the bottom of the second grinding chamber and used for providing power for grinding of the grinding mechanisms in the second grinding chamber, when the jet flow frequency acquired by the central control unit is larger than a preset value, the power parameters of the first power device and the second power device are increased by the central control unit, when the jet flow frequency acquired by the central control unit is smaller than the preset value, the power parameters of the first power device and the second power device are reduced by the central control unit, so that the produced nano silver product meets the preset standard.
2. The method for preparing silver nanopowder with high sintering activity according to claim 1, wherein the central control unit obtains the initial weight m0 of silver nanopowder at the beginning of the second grinding device grinding, and after a first preset time t1, the central control unit obtains the weight m1 of silver nanopowder settled at the bottom of the second grinding device through the detection device, and the ratio of the weight m1 of silver nanopowder settled at the bottom of the second grinding device to the initial weight m0 of silver nanopowder at the beginning of the second grinding device grinding is preset as the fraction m of particle size fraction failure, wherein m is m1/m0,
when M is less than or equal to M1, the central control unit judges that the reject ratio of the current particle size meets the preset standard;
when M1 is more than M and less than M2, the central control unit increases the jet flow frequency P of the injection supercharging device to P1, and sets P1 to P x (1+ (M-M2)/M2);
when M is larger than or equal to M2, the central control unit prolongs the grinding time D of the first grinding device to D1 and sets D1 to Dx (1+ (M1-M)/M1);
the center control unit is preset with a particle size failure rate M, and is set with a first preset particle size failure rate M1 and a second preset particle size failure rate M2.
3. The method for preparing silver nanopowder with high sintering activity according to claim 2, wherein the central control unit obtains the initial volume V0 of silver nanopowder at the initial time in the sintering device through the image acquisition device, and obtains the volume V1 of silver nanopowder through the second preset time t2, the central control unit sets the sintering volume change rate V of silver nanopowder, and sets V ═ V0-V1)/V0, wherein,
when V is less than or equal to QWi, the central control unit increases the sintering temperature Ti to Ti1 and prolongs the sintering time Si to Si 1;
when V is larger than QWi, the central control unit reduces the sintering temperature Ti to Ti2, sets Ti2 and shortens the sintering time Si to Si 2;
wherein, the central control unit presets sintering stages W, wherein, a first preset sintering stage W1(T1, S1, QW1), a second preset sintering stage W2(T2, S2, QW2), is set, the first preset sintering temperature is T1, the first preset sintering stage sintering time S1, the first preset sintering stage volume change rate standard value is QW1, is set, the second preset sintering temperature is T2, the second preset sintering time is S2, the second preset sintering stage volume change rate standard value is QW2, if the second preset time T2 is in the first preset sintering time, the central control unit selects the first preset sintering temperature T1 as the current sintering temperature, the first preset sintering stage sintering time S1 as the current sintering time, and the first preset sintering time volume change rate standard value is QW1, if the second preset time T2 is the second preset sintering time, the central control unit selects the second preset sintering temperature T2 as the current sintering temperature, selects the second preset sintering time S2 as the current sintering time, and selects the second preset sintering volume change rate standard value QW2 as the evaluation standard of the volume change rate.
4. The method for preparing silver nanopowder with high sintering activity according to claim 3, wherein when the central control unit obtains the ith preset sintering time volume change rate standard value QWi, wherein i is 1,2, and the real-time volume change rate of the silver nanopowder sintering is less than or equal to the selected ith preset sintering time volume change rate standard value QWi, the central control unit increases the current sintering temperature Ti to Ti1, so that the current silver nanopowder sintering meets the preset standard, and sets Ti1 to Ti x (1+ (QWi-V)2QWi); the central control unit prolongs the current sintering time Si to Si1 so as to ensure that the sintering in the current sintering stage is sufficient, and the central control unit is set to Si1 ═ Si x (1+ (QWi-V)2/QWi)。
5. The method for preparing silver nanopowder with high sintering activity according to claim 2, wherein when the volume change rate of the obtained silver nanopowder in real time is greater than the i-th preset sintering time volume change rate standard value QWi, wherein i is 1,2, the central control unit lowers the current sintering temperature Ti to Ti2 to make the current silver nanopowder sintering meet the preset standard, and sets Ti2 to Ti x (1- (V-QWi)/QWi); the central control unit shortens the current sintering time Si to Si2 to make the current sintering stage fully sintered, set to Si2 ═ Si × (1+ (V-QWi)/QWi).
6. The method for preparing silver nanopowder with high sintering activity according to claim 3, wherein the central control unit presets a standard sintering temperature value Ti0, and adjusts the jet frequency of the injection pressurizing device according to the comparison between the adjusted sintering temperature and the standard sintering temperature value, wherein,
when Tiq is less than Ti0, the central control unit reduces the jet flow frequency P1 to P11 of the injection supercharging device, and sets P11 to P1 x (1- (Ti0-Tiq)/Ti 0);
when Tiq is more than Ti0, the central control unit increases the jet flow frequency P1 to P12 of the injection supercharging device, and sets P12 to P1 x (1+ (Tiq-Ti0)/Ti 0);
the central control unit presets a first preset sintering stage sintering temperature standard value T10 and a second preset sintering stage sintering temperature standard value T20, wherein i is 1,2, and q is 1, 2.
7. The method for preparing silver nanopowder with high sintering activity according to claim 5, wherein the central control unit presets a jet flow frequency standard value P0, and adjusts the power parameters of the first power device and the second power device according to the comparison between the adjusted jet flow frequency and the standard value, wherein,
when Pbj is larger than or equal to P0, the central control unit increases the first power device power parameters F1 to F11, sets F11 to F1 multiplied by Pbj/P0, increases the second power device power parameters F2 to F21, and sets F21 to F2 multiplied by Pbj/P0;
when Pbj < P0, the central control unit decreases the first power plant power parameters F1 to F12, sets F12 to F1 × Pbj/P0, decreases the second power plant power parameters F2 to F22, sets F22 to F2 × Pbj/P0;
wherein, b is 1,2, j is 1, 2.
8. The method for preparing silver nanopowder with high sintering activity according to claim 5, wherein when the central control unit increases the power parameter of the i-th power device, the central control unit decreases the rotation speed Li to Li1 of the i-th grinding chamber grinding mechanism, sets Li 1-Li x (1- (Far-Fa)/Fa), and simultaneously extends the grinding time D1 to D11 of the first grinding device, sets D11-D1 x (1+ (Far-Fa)/Fa), and the central control unit presets the rotation speed L1 of the first grinding chamber grinding mechanism and the rotation speed L2 of the second grinding chamber grinding mechanism, wherein a is 1,2, and r is 1, 2.
9. The method for preparing silver nanopowder with high sintering activity according to claim 8, wherein when the central control unit decreases the power parameter of the i-th power device, the central control unit increases the rotation speed Li to Li2 of the grinding mechanism of the i-th grinding chamber, sets Li2 ═ Li x (1- (Fa-Far)/Fa), and simultaneously shortens the grinding time D1 to D12 of the first grinding device, sets D12 ═ D1 × (1+ (Fa-Far)/Fa).
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