JP2010036073A - Method and apparatus for mixing granular material with liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and apparatus for mixing a granular material with a liquid in which the fluidity is effectively increased without surfactants or the like and the fluidity is carefully controlled. <P>SOLUTION: In the method of mixing the granular material with the liquid, one or more ion species are added to the liquid, and an AC electromagnetic field or an electrostatic field is applied, in mixing the granular material with the liquid. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mixing method and a mixing apparatus for a granular material and a liquid that can reduce the viscosity and yield value of the mixture and easily and uniformly mix them when mixing the granular material and the liquid. It is about.

  In the manufacture of building materials, ceramic products, etc., there is a step of uniformly mixing powder and liquid, pouring them into a predetermined mold, and curing them. When mixing the powder and liquid, the mixture is poured into the mixture in order to reduce the viscosity and yield value of the fluid powder and liquid mixture in order to be poured into the mold within a predetermined time. Surfactant and dispersant are added.

However, since the surfactant is expensive, there is a problem in that the manufacturing cost increases.
Therefore, when the amount of the surfactant added is reduced, a large stirring force is required to mix the powder and liquid, resulting in a problem that a powerful stirring device is required.

  Furthermore, if the work of pouring the mixture into the mold becomes longer, the fluidity of the mixture deteriorates during that time, and the mold is insufficiently filled or becomes a defective molded product, resulting in a high yield. There also arises a problem of lowering.

  Therefore, in the following Patent Document 1, when producing ready-mixed concrete containing cement, aggregate, and water, the interface is obtained by kneading water, cement, and aggregate, to which magnetic force is applied by a magnetic field generator. There has been proposed a method for producing ready-mixed concrete in which desired fluidity can be obtained even when the amount of activator added is reduced.

However, in the conventional method for producing ready-mixed concrete, since only a magnetic force is applied, the effect of improving fluidity is limited.
In addition, in mixing this type of powder and liquid, depending on the time until the mixture has been poured into the mold, the fluidity is ensured, or the curing time of the mixture is increased to increase the production rate. There is also a request to control the fluidity of the mixture according to various production conditions, but there is also a problem that it is difficult to sufficiently cope with the conventional technique.
JP 2005-305678 A

  The present invention has been made in view of such circumstances, and when mixing powder and liquid, it is possible to effectively improve the fluidity without using a surfactant or the like, and to finely control the fluidity. It is an object of the present invention to provide a mixing method and a mixing apparatus for a granular material and a liquid that can be used.

  In order to solve the above-mentioned problem, the method of mixing powder and liquid according to claim 1 adds one or more kinds of ionic species to the liquid when mixing the powder and liquid, and an alternating electromagnetic field. Alternatively, a static magnetic field is applied.

  Here, the invention according to claim 2 is the invention according to claim 1, wherein the ionic strength of the mixture of the granular material and the liquid is 0.001 mol / L than before addition. It is added so that it may become larger above.

  Furthermore, the invention according to claim 3 is the invention according to claim 1 or 2, wherein the magnetic field intensity and / or frequency of the AC electromagnetic field or static magnetic field is set to 0. The absolute value of the zeta potential of the granular material is 0. It is characterized by controlling so as to be higher by 1 mV or more.

  Further, in the invention according to claim 4, in the invention according to any one of claims 1 to 3, in addition to the application of the AC electromagnetic field or the static magnetic field, it is possible to further increase the zeta potential of the granular material. A voltage or current or an ultrasonic wave is applied, and the invention according to claim 5 is characterized in that the frequency of the ultrasonic wave is set to a multiple of the frequency of the AC electromagnetic field. Is.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, characterized in that the granular material is cement and the liquid is water.

  Next, the powder and liquid mixing apparatus according to claim 7 is a container for storing the liquid and the granular material to which one or more kinds of ionic species are added, and the container is rotatably provided in the container. A stirring blade that stirs the liquid and the granular material, and a driving unit that rotationally drives the stirring blade, and the body portion, the bottom portion, or the stirring blade of the container is made of a nonmagnetic material, and is formed by the nonmagnetic material. A magnetic field generating coil for applying a magnetic field to the mixture of the liquid and the granular material in the container is incorporated in the formed portion. In addition, as said container, the thing of various forms, such as a rod cylinder shape, a horizontal cylinder shape, a 2 cylinder shape, and spherical shape, can be used. In addition, as for the stirring blades, those having various shapes such as a paddle type, an impeller type, a propeller type, a screw type, a roller type, and a mortar type can be applied.

  The invention according to claim 8 is the invention according to claim 7, wherein the magnetic field generating coil is provided with an inverter for controlling the frequency of the magnetic field applied by the magnetic field generating coil. It is what.

As a result of basic research on the surface science of solid particles (powder particles) in a liquid, the present inventors have obtained the following knowledge.
First, the particles in the liquid are charged, and when an electrostatic repulsion greater than the attractive force between the particles acts, the particles are dispersed to lower the surface tension of the liquid, and further reduce the viscosity of the slurry and increase the fluidity. give. The zeta potential corresponds to the magnitude of this electrostatic repulsion. Here, when the zeta potential approaches zero, particle aggregation occurs and fluidity is deteriorated.

The above is general knowledge in interface science, but until now there has been no knowledge on how to improve the fluidity by controlling the absolute value of the zeta potential of the powder itself.
That is, since the zeta potential is a function of the dielectric constant of the solution, the absolute value of the zeta potential on the particle surface can be increased by a magnetic field capable of controlling the dielectric constant. However, there is a limit to the effect of increasing the absolute value of the zeta potential only by applying a magnetic field.

  Therefore, when a solution or liquid such as a water-soluble compound containing one or more ionic species (anions or cation ions) or an electrolytic solution is added to the mixture of the granular material and the liquid, the ionic species are deposited on the particle surface. When the magnetic field is applied, this charge species acts on the particle surface and effectively increases the absolute value of the zeta potential. As a result, the viscosity of the mixture of the granular material and the liquid decreases. The knowledge that it becomes easy to do.

  The present invention has been made on the basis of such knowledge. According to the mixing method according to any one of claims 1 to 6 and the mixing device according to claim 7 or 8, an electrostatic magnetic field is applied to the granular material and the liquid. In addition, when mixing by applying an AC electromagnetic field, one or more ionic species are further added, so compared with a mixing method in which no electromagnetic field is applied or a mixing method in which only an electromagnetic field is applied. The viscosity of the mixture can be lowered and made uniform.

As a result, the amount of the expensive surfactant added can be reduced, and the fluidity of the mixture of the granular material and the liquid can be effectively increased without using a powerful stirrer. .
In addition, change the strength and frequency of the magnetic field, insert the electrode into the stirrer, pre-process the raw material with the magnetic field and the electrode, and select the water-soluble compound and solution type and concentration for adding ionic species as appropriate. Thereby, the effect that it becomes easy to control the viscosity of the mixture of the said granular material and a liquid is also acquired.

  Here, as the amount of ionic species added to the mixture of the granular material and the liquid, as in the invention of claim 2, the ionic strength of the mixture of the granular material and the liquid is higher than that before the addition. It is preferable that the amount be 0.001 mol / L or more. In addition, the said ionic strength is synonymous with what is generally defined in the chemical field | area. That is, for all the ions in the solution of the powder and liquid mixture, the product of the molar concentration of each ion and the square of the valence are added together, and the product is halved. Is an indicator of the electrical interaction of ions.

  Moreover, in order to improve the fluidity effectively when mixing a mixture of powder and liquid to which one or more ionic species are added, the AC electromagnetic field or static magnetic field applied to the mixture is also claimed. As in the invention described in Item 3, it is preferable to control the magnetic field strength and / or the frequency so that the absolute value of the zeta potential of the powder is increased by 0.1 mV or more.

  Furthermore, according to the knowledge of the present inventors, an AC electromagnetic field or a static magnetic field is applied to a mixture of powder and liquid to which one or more ionic species are added as in the invention described in claim 4. In addition, the effect of improving the fluidization can be further increased by applying a voltage or current or an ultrasonic wave capable of increasing the zeta potential of the granular material. Here, when applying the frequency of the ultrasonic wave, it is preferable to set the frequency to a multiple of the frequency of the AC electromagnetic field, as in the fifth aspect of the invention.

1 to 4 show first to fourth embodiments of a powder and liquid mixing apparatus according to the present invention, and the same components are denoted by the same reference numerals and the description thereof is simplified. .
First, FIG. 1 shows a first embodiment of the mixing apparatus, and reference numeral 1 in the drawing is a container. In this container 1, a cylindrical body portion 2 and a bottom portion 3 that closes the lower end portion of the body portion 2 are integrally formed of a nonmagnetic metal, and one or more ionic species are added therein. It contains a mixture of liquid and granular material.

  And in this container 1, the rotating shaft 4 arrange | positions the axis line, and is arrange | positioned rotatably. A plurality of (four in the figure) stirring blades 5 protruding in the radial direction are fixed to the outer periphery of the rotating shaft 4, and a drive for rotating the rotating shaft 4 to the lower surface of the bottom portion 3. A motor (driving means) 6 is provided.

  Furthermore, a coil (magnetic field generating coil) 7 for generating a magnetic field inside and applying a magnetic field to the mixture is wound around the body 2 of the container 1 in the circumferential direction. Further, an inverter 8 for controlling the frequency of the magnetic field applied by the coil 7 is provided on the outer periphery of the body portion 2.

  In the mixing apparatus of the second embodiment shown in FIG. 2, a coil (magnetic field generating coil) 9 wound in the circumferential direction is disposed on the bottom 3 of the container 1, and the outer periphery of the body 2 Similarly, an inverter 8 (not shown) for controlling the frequency of the magnetic field applied by the coil 9 is provided.

Furthermore, in the mixing apparatus of the third embodiment shown in FIG. 3, a plurality of independent coils (magnetic field generating coils) 10 are arranged on the body 2 of the container 1, and the frequency of these coils 10 is converted to an inverter. 8 is variable.
In the mixing device of the fourth embodiment shown in FIG. 4, a coil (magnetic field generating coil) 11 having a variable frequency is incorporated in each stirring blade 5.

Next, an embodiment in which the powder and liquid mixing method according to the present invention using any of the mixing apparatuses shown in FIGS. 1 to 4 is applied to the case of producing mortar will be described.
First, water (liquid) and cement (powder particles) are supplied into the container 1, and at least one ionic species is added to the mixture.

  Here, as the ionic species to be added, those that are soluble in the liquid to be used are preferable. When the powder is cement and the liquid is water, sodium sulfate, potassium sulfate, calcium sulfate, magnesium sulfate, magnesium hydroxide , Sodium hydroxide, ammonia, sodium silicate, sodium bicarbonate electrolyzed water, potassium hydroxide, potassium carbonate, sodium carbonate, tartaric acid, citric acid, sodium citrate, sodium aluminate, 1 • ethyl 3 • methylimidazolium • Br, 1 • Butyl 3, methyl imidazolium, Br, etc. can be used.

  The ionic species is added in such an amount that the ionic strength of the cement and water mixture is 0.001 mol / L or more, more desirably 0.01 mol / L or more larger than before the addition.

The coil 7 (9, 10, 11) is energized to apply an alternating electromagnetic field or a static magnetic field to the mixture in the container 1 while rotating the rotating shaft 4 by the drive motor 6 by the stirring blade 5. Stir and mix the above mixture.
At this time, the inverter 8 controls the magnetic field strength and frequency of the AC electromagnetic field or static magnetic field so that the absolute value of the zeta potential of the cement is increased by 0.1 mV or more.

  Specifically, the magnetic field strength and frequency are such that the magnetic field strength is 70 μT or more and the frequency is 5 kHz or more, more preferably the magnetic field strength is 100 μT or more and the frequency is 7 kHz or more.

Furthermore, in parallel with this, if a voltage, current, or ultrasonic wave capable of increasing the zeta potential of the cement is applied to the mixture in the container 1, the fluidity improving effect can be further increased.
Here, the application of ultrasonic waves is a means for allowing ionic species under an electromagnetic field to effectively work to increase the absolute value of the zeta potential of the cement. When the applied magnetic field is an alternating current, the magnetic field In order to synchronize with the frequency of the magnetic field, it is preferable to apply so that it is a multiple of the frequency of the magnetic field. For example, when the AC electromagnetic field is applied at 7 kHz, it is preferable to apply the ultrasonic wave at 28 kHz.

In addition, the application of current is a means to enable ionic species under an electromagnetic field to effectively work to increase the absolute value of the zeta potential of the cement, and if the powder is cement and the liquid is water, Considering the properties, it is desirable to set the current to 100 mA to 3 A.
Furthermore, the applied voltage is a means for allowing ionic species under an electromagnetic field to effectively act on the zeta potential of the granular material. Similarly, if the granular material is cement and the liquid is water, operability In view of the above, it is desirable to set the voltage to 1.5V to 12V.

  In the above embodiment, the method for mixing powder and liquid according to the present invention has been described only in the case where the powder is cement and the liquid is water. The present invention is not limited, and in the present invention, a magnetic field is not simply applied, but one or more ionic species are added, and if necessary, an ultrasonic wave, an electric current or a voltage is applied, and a solid in a liquid By controlling the absolute value of the zeta potential by controlling the absolute value of the zeta potential by the ionic species and the magnetic field to which the surface potential of the particles is added, the dispersibility of the particles is improved, and the kneaded mixture of the liquid and particles Therefore, it can be applied to the mixing of various powders and liquids.

(Examples 1-7)
Potassium sulfate was added as the ionic species, and the effect of a magnetic field on the kneading of cement mortar mixed with fly ash was evaluated by the flowability of the mortar.
The materials used are ordinary Portland cement (N), fly ash (FA), high-performance water reducing agent Mighty 150 manufactured by Kao Corporation, and ISO standard sand for JIS mortar testing in the proportions shown in Table 1. ) Kneaded by the method according to the cement association New RC technical committee report "quality standard of cement for high-strength concrete (draft)".

  At this time, in Examples 1 to 7, the potassium sulfate was added so as to be 0.1 mol / L larger than the ionic strength of the mortar to which potassium sulfate was not added. In addition, the value measured in advance by chemical analysis was used for the measurement of the ionic strength in the liquid phase of the mortar to which potassium sulfate was not added. In addition, the magnetic field is applied in the mixing device container with an alternating magnetic field with a magnetic field strength of 100 μT to 400 μT and a frequency of 100 kHz to 500 kHz, and kneaded with varying amounts of water reducing agent, and the physical properties of the soft mortar (fresh properties) ) Was measured.

  Further, as Comparative Examples 1 and 2, the case of using a normal kneading method without adding ionic species and applying a magnetic field, and the case of using a kneading method without adding ionic species and applying a magnetic field The physical properties (fresh properties) of each soft mortar were measured and compared with the above Examples 1-7.

  For the evaluation of the fluidity, a flow test apparatus of JIS R 5201 “Cement physical test method” was used, and the spread of the flow when the flow cone was removed upward was measured as “0 stroke flow”. In addition, as an index of viscosity, the time required for the mortar placed in the L-type flow tester for mortar to reach 150 mm was measured and converted into an average speed to obtain “L flow speed”. The air volume measurement was in accordance with ASTM C 185 9.4. The amount of air in the mortar was adjusted with an air amount adjusting agent.

  Table 2 shows the results. When potassium sulfate was added as an ionic species and a magnetic field was applied to increase the frequency to 200 kHz or higher, the mortar flow and flow rate increased, and the mortar viscosity decreased. It has been demonstrated that fluidity is improved. As a result, the amount of water reducing agent added can be reduced.

(Examples 8 to 10)
The fresh properties of each of the mortars of Examples 8 to 10 which were kneaded under the same composition, magnetic field strength, and frequency conditions as those shown in Comparative Example 2 and with addition of sodium sulfate as an ionic species were similarly determined. It was measured. Table 3 shows the results. From Table 3, it was demonstrated that the addition of sodium sulfate increased both the zero stroke flow and the L flow rate, and improved the mortar fluidity, as compared with Comparative Example 2 in which no ionic species was added.

(Examples 11 to 13)
Each of the fresh properties of the mortars of Examples 11 to 13 kneaded under the same formulation, magnetic field strength, and frequency conditions as those shown in Comparative Example 2 above and with magnesium sulfate added and kneaded as the ionic species was similarly applied. It was measured. Table 4 shows the results. From Table 4, it was demonstrated that the addition of magnesium sulfate increased both the zero-stroke flow and the L flow rate, and improved the mortar fluidity, as compared with Comparative Example 2 in which no ionic species was added.

(Examples 14 to 18)
Next, the effect of ionic species and magnetic field on the mixing of concrete was evaluated.
Ordinary Portland cement (N), fly ash (FA), Kisarazu mountain sand (S), Hachioji hard sandstone 2005 (G), polycarboxylic acid-based high-performance AE water reducing agent (BASF Pozoris Leo build SP-8SX2) and Uses air volume regulator (BASF Pozzolith Micro Air 775S), uses calcium sulfate as ionic species, and adds 0.1 mol / L higher than the ionic strength of concrete without calcium sulfate. did. For the measurement of the ionic strength of the concrete to which calcium sulfate was not added, a value measured in advance by chemical analysis was used.

Table 5 shows the blending of the concrete, and Table 6 shows test items and test methods. The target slump flow was 60 cm and the amount of air was 5%, and trial and error were repeated to determine the formulation. The amount of air was adjusted with an air amount adjusting agent.
Then, an AC magnetic field with a magnetic field strength of 400 μT to 800 μT and a frequency of 100 kHz to 1500 kHz is applied to the container of the mixing apparatus, and the kneading is performed by changing only the frequency and the amount of water reducing agent added under the condition that the amount of ionic species added is constant. The physical properties (fresh properties) of the soft concretes obtained in Examples 14 to 18 were measured.

  In addition, for each of Comparative Examples 3 and 4 using a normal kneading method without adding an ionic species and applying a magnetic field, and Comparative Examples 3 and 4 using a kneading method without adding an ionic species and applying a magnetic field, Fresh properties were measured and compared with Examples 14-18 above.

  Table 7 shows the test results. From Table 7, it was found that the slump flow, L flow, and L initial velocity values increased at a frequency of 100 kHz or more, and the flow time of 50 cm was shortened to improve the fluidity of concrete. It was also found that this tendency becomes significant at 500 kHz and above.

(Examples 19 to 21)
Example obtained by adding and kneading an ionic liquid (room temperature molten salt) having a melting point of 12 ° C. under the conditions of an AC electromagnetic field (magnetic field strength 200 μT, frequency 100 kHz) at room temperature of 20 ° C. in Example 4 The fresh properties of 19-21 mortars were measured and compared with Comparative Example 2 above. Table 8 shows the results. From Table 8, it was confirmed that the addition of the ionic liquid increased both the zero hit flow and the L flow rate, and improved the fluidity of the mortar.

(Examples 22 to 24)
The fresh properties of the mortars of Examples 22 to 24 obtained by adding and kneading JIS standard sodium silicate No. 3 under the conditions of the AC electromagnetic field of Example 4 were measured and compared with Comparative Example 2 above. . Table 9 shows the results. From Table 9, it can be seen that in Examples 22 to 24 to which sodium silicate was added, both the zero-stroke flow and the L flow rate were increased, and the fluidity of the mortar was improved.

(Examples 25-27)
Similarly, under the AC electromagnetic field conditions of Example 4, sodium bicarbonate electrolyzed water (NaHCO ₃ ) was added, and the mixture was stirred by the mixing apparatus shown in FIG. 2 so as to assist the action of ions on the particle interface. The fresh properties of the mortars of Examples 25 to 27 obtained by equipping the electrodes so that the wings were positive electrodes and the container wall surfaces being negative electrodes and being energized at 500 mA were kneaded. Table 10 shows the results. From Table 10, it can be seen that by adding sodium bicarbonate electrolyzed water, both the 0-stroke flow and the L-flow rate were increased as compared with Comparative Example 2, and the fluidity of the mortar was improved. The amount of water used is the amount obtained by subtracting the amount of electrolyzed water.

(Examples 28 to 30)
The mixing apparatus shown in FIG. 2 is used to add an alkaline electrolyte containing potassium hydroxide as a main component under the condition of an electrostatic magnetic field with a magnetic field strength of 500 μT and to assist the action of ions on the particle interface as an auxiliary. Thus, Examples 28 to 30 were obtained by mounting the electrode so that the stirring blade was a negative electrode and the container wall surface being a positive electrode, and conducting kneading by energizing at 400 mA. And the fresh property of the mortar of these Examples 28-30 was measured, and it contrasted with the said comparative example 2 similarly.

  Table 11 shows the results. From Table 11, it was confirmed that the addition of the alkaline electrolyte increased both the zero stroke flow and the L flow rate, and improved the fluidity of the mortar. The amount of water used is the amount obtained by subtracting the amount of electrolyzed water.

(Examples 31-33)
By using the mixing apparatus shown in FIG. 2, a predetermined amount of raw material (cement + fly ash) used in advance is added to the total amount of water used and colloidally left for 3 minutes, which is difficult to obtain by ordinary kneading. An ion species was prepared by ionizing the components of (pretreatment). Thereafter, the remaining raw materials were added and stirred under the same AC electromagnetic field conditions as in Example 4 to obtain Examples 31 to 33. Table 12 shows the amount of raw material added to the total amount of water and the measurement results of the fresh properties of these mortars in comparison with Comparative Example 2 in the pretreatment of Examples 31 to 33. From Table 12, in the pretreated Examples 31 to 33, both the zero-stroke flow and the L flow speed were larger than those in Comparative Example 2, and the effect of improving the fluidity of the mortar was observed.

(Examples 34 to 38)
To the slurry composed of 75% magnesia powder and 25% 1-propanol as the organic solvent, an ionic liquid (room temperature molten salt) with a melting point of 12 ° C. is added as an ionic species, 0.1%, and the AC power shown in Table 13 is added. Stirring was performed under magnetic field conditions, and the respective viscosities were measured and compared with Comparative Example 5 above. As can be seen from the results in Table 13, the viscosity was reduced by adding an ion species and a magnetic field.

(Example 39)
Table 14 shows a comparison result in the case where an ultrasonic wave having twice the magnetic field frequency is applied to Example 14 described above. As is clear from Table 14, the viscosity of the mortar was reduced by the effect of applying ultrasonic waves synchronized with the magnetic field frequency.

(Example 40)
Example 40 and Comparative Example 6 were prepared in the same manner as Example 8 and Comparative Example 2 shown in Table 3 in the same electromagnetic field conditions and composition as in Example 40 and Comparative Example 6, and the fresh properties and mortar of each mortar. The zeta potential of the cement inside was measured. Table 15 shows the results. The zeta potential was measured using an ESA8000 manufactured by Matec, which can measure the zeta potential of a concentrated slurry by an electrokinetic acoustic method.

  From Table 15, the absolute value of the zeta potential of the cement in the mortar of Example 40 is larger than that of Comparative Example 6 where no addition is made due to the effect of the addition of sodium sulfate, which is an ionic species. It can be seen that the L flow rate increased and the fluidity of the mortar improved.

1 is an overall perspective view showing a first embodiment of a powder and liquid mixing apparatus according to the present invention. It is a whole perspective view which shows 2nd Embodiment same as the above. It is a whole perspective view which shows 3rd Embodiment same as the above. It is the whole perspective view which shows 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 2 Trunk part 3 Bottom part 4 Rotating shaft 5 Stirring blade 6 Drive motor (drive means)
7, 9, 10, 11 coil (magnetic field generating coil)
8 Inverter

Claims (8)

  A method of mixing a granular material and a liquid, which comprises adding one or more ion species to the liquid and applying an alternating electromagnetic field or a static magnetic field when mixing the granular material and the liquid.   2. The granular material according to claim 1, wherein the ionic species is added so that the ionic strength of the mixture of the granular material and the liquid is 0.001 mol / L or more higher than before addition. And liquid mixing method.   3. The powder according to claim 1, wherein the magnetic field strength and / or frequency of the alternating electromagnetic field or static magnetic field is controlled so that the absolute value of the zeta potential of the granular material is increased by 0.1 mV or more. A method of mixing particles and liquid.   4. In addition to the application of the AC electromagnetic field or the static magnetic field, a voltage, current, or ultrasonic wave that can further increase the zeta potential of the granular material is applied. Mixing method of powder and liquid.   The method for mixing powder and liquid according to claim 4, wherein the frequency of the ultrasonic wave is set to a multiple of the frequency of the AC electromagnetic field.   The method for mixing powder and liquid according to any one of claims 1 to 5, wherein the powder is cement and the liquid is water.   A container for storing a liquid and a granular material to which one or more ionic species are added, a stirring blade that is rotatably provided in the container and stirs the liquid and the granular material, and the stirring blade is driven to rotate. And a body portion, a bottom portion, or the stirring blade of the container is made of a nonmagnetic material, and a magnetic field is applied to the mixture of the liquid and the granular material in the container in a portion formed by the nonmagnetic material. An apparatus for mixing powder and liquid, characterized in that a magnetic field generating coil for applying an electric field is incorporated.   The apparatus for mixing powder and liquid according to claim 7, wherein the magnetic field generating coil is provided with an inverter for controlling the frequency of the magnetic field applied by the magnetic field generating coil.

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