JP2003340269A - Slurry, method for administering slurry, method for producing slurry, and granule - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To consistently and comprehensively administer administration parameters including source administration, concerning the state of slurry, the production of the slurry, the post-processing of the slurry, and a final product produced by using the slurry. <P>SOLUTION: The concentration of particles in a solid-liquid dispersion system and the viscosity of the slurry are selected to fall into a spherical granule region out of the spherical granule region and a nonspherical granule region which are obtained from the data showing the relationship between the degree of aggregation of the particles expressed by D/Do (D is the primary particle size of the dry particles; and Do is the particle size of the aggregated particles) and the viscosity of the slurry. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a slurry and a method for producing the slurry.

[0002]

A slurry as a solid-liquid dispersion system in which solid particles are dispersed and mixed in a liquid is used not only in the field of fine ceramics but also in a wide range of industrial fields such as abrasive grains, cement, resins and paints. The slurry is required to have not only characteristics such as fluidity, coating characteristics and pot shell life as a solid-liquid dispersion system, but also various characteristics required for post-processing using the slurry as a material. This is used when the slurry is used after being formed into a granular shape such as granules, a flat plate shape such as an extruded sheet, or a post-processed three-dimensional solid shape such as injection molding. This is because the properties of the slurry itself greatly affect the post-processability and the properties of the post-processed product in such a case.

As described above, since the slurry has an important utility value in industry, various studies have been accumulated on the characteristics of the slurry and various characteristics required when the slurry is post-processed. For example, a system that enables continuous preparation of polishing slurry (Japanese Patent Laid-Open No. 2000-30895).
No. 7), a slurry in which a polymer and inorganic particles are dispersed by adjusting the ζ potential (JP-A-2000-273311), a toner for copying machines (JP-A-2001-31427), and a slurry as a ceramic raw material containing a dispersant. (JP 20
No. 01-48654), a method for manufacturing a ceramic green sheet (Japanese Patent Laid-Open No. 2001-31474), and the like can be seen in recent trends.

As described above, the characteristics of the slurry are not only the solvent but also solid particles (also called primary particles) as a solid-liquid dispersion system.
It is also affected by the chemical, physical and electrochemical effects including the solid-liquid interface of.

Further, taking ceramics as an example, the flowability of the granules in the subsequent steps such as forming the slurry into granules or green sheets and then forming the granules, forming characteristics, and subsequent sintering characteristics are greatly affected. give. As described above, various factors are intricately intertwined with the characteristics required of the slurry.

Therefore, paying attention to the process of producing granules by the spray drying method, an example of using a binder and an emulsifier together (Japanese Patent Publication No. 63-
No. 27051) or an example of adding a solvent in which a binder is difficult to dissolve when granulating granules having a roundness (Kosho 63-29).
579) and the like, and more recently, there is a study (Model No. 106, No. 12 (1998)) of modeling the relationship between the pH adjusting conditions of the slurry and the shape of the granules.

Further, methods such as macroscopic dispersion using an additive and adjustment of ζ potential by a functional group of a polymer are also known (Japanese Patent Laid-Open No. 2000-273311 etc.).

Further, when granulating granules using a slurry as a raw material, attention is paid to the bulk density of the granules and the particle size of the granules to manage the granulation work from the resistance of the impeller (Japanese Patent Laid-Open No. 2-212058).
(001-29769 gazette etc.) are also known.

By the way, the most important item required for granules is how to make solid spherical granules that can be easily molded.

However, in the above-mentioned conventional method, even if the manufacturing parameters of the slurry, the state of the slurry, the post-processing of the slurry, and the final product produced by using the slurry are known for each individual process. In the relation of the process from the starting material to the final product, the essential characteristic requirements that are the control parameters for producing solid spherical granules have not been clarified. The question of what happened was still open.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a slurry suitable for producing spherical granules, a slurry management method, and a slurry manufacturing method.

[0012]

[Means for Solving the Problems] 1. Slurry In order to solve the above-mentioned problems, first, the present invention, in the slurry that particles of the solid component constitutes a solid-liquid dispersion system in the liquid, the concentration of the particles, the average particle of the primary particles in the dispersed state of the particles When the diameter is D and the average particle size of the agglomerated particles due to the agglomeration of the particles is D0, a spherical granule region obtained from data showing the relationship between the degree of agglomeration represented by (D / D0) and the slurry viscosity, and Of the non-spherical granule regions, it is selected to fit within the spherical granule region.

That is, in a slurry in which particles of a solid component form a solid-liquid dispersion system in a liquid, the degree of aggregation (D / D0)
From the experimental data showing the relationship with the slurry viscosity, for example,
When the graph was created, it was found that the graph showed spherical and non-spherical granular regions. Therefore, if the particle concentration or slurry viscosity of a certain slurry falls within the spherical granule region shown in this graph, the slurry guarantees the production of spherical granules.

The relationship between the degree of coagulation (D / D0) and the viscosity of the slurry differs depending on the particle material contained in the slurry. In any case, in the case of graphing, the spherical granular region and the non-spherical granular region are shown. Indicates. Therefore, by collecting experimentally the relationship data between the degree of aggregation (D / D0) and the slurry viscosity for each particle material contained in the slurry, it is possible to obtain a slurry suitable for obtaining spherical granules for each particle material. Can be obtained.

By the way, when the present invention is applied to the field of fine ceramics, the slurry contains ceramic powder, a binder, a dispersant, a plasticizer and the like, and further contains a defoaming agent, a coagulant and the like. Sometimes. These components are mixed and stirred to produce a slurry.

However, even if the viscosity of the slurry and the concentration of the ceramic powder are selected so as to fall within the spherical granule region according to the above-mentioned teaching of the present invention, the amount of the binder is increased when the stirring is continued for a long time. Depending on the concentration of ceramic powder or ceramic powder, it may enter the non-spherical granule region from the spherical granule region. For example, the slurry properties change during granulation with a spray dryer, etc. It was found that the obtained granules of No. 1 may become depressed granules.

In order to solve the problem of the change with time, the inventors of the present invention have conducted intensive research. As a result, it has been found that certain additives are extremely effective in suppressing the phenomenon of non-spherical granular region migration due to stirring. This additive is
Having at least one hydroxyl group, and a carboxyl group,
It is a non-polymeric organic compound having a functional group selected from the group consisting of carboxylates, sulfonic acids, sulfonates, phosphoric acids, phosphates, amines, and quaternary amine salts.

Examples of the organic compound include hydroxyl group-containing carboxylic acid, hydroxyl group-containing carboxylate, hydroxyl group-containing sulfonic acid, hydroxyl group-containing sulfonate, hydroxyl group-containing phosphoric acid,
It may be selected from the group consisting of hydroxyl group-containing phosphates, hydroxyl group-containing amines, and hydroxyl group-containing quaternary ammonium salts.
More specifically, this organic compound is selected from the group consisting of citric acid, meso-tartaric acid, hydroxyl-containing lower carboxylic acid, hydroxyl-containing lower alkenylcarboxylic acid, hydroxyl-containing lower alkynylcarboxylic acid, hydroxyl-containing aromatic carboxylic acid, and combinations thereof. Can be selected.

In the application to the field of fine ceramics, while further research was conducted, when a plurality of types of ceramic powders having the same composition and the same manufacturing process but different manufacturing lots were used, We faced the problem that the ceramic powder would enter the spherical granule region, whereas the other lots of ceramic powder would enter the non-spherical granule region. Since this problem directly affects industrial mass production, it is a problem that must be solved.

In order to solve this problem, the present inventors further conducted earnest research. As a result, they have found that the addition of alkali is extremely effective in solving this problem. Specific examples include ammonia, sodium hydroxide, sodium carbonate, sodium hydrogen carbonate and the like.

2. Slurry Management Method In the slurry management method according to the present invention, the slurry is dropped on a flat resin surface to form hemispherical droplets.
Next, the droplet is heated to reduce the content of the liquid phase component, and the property of the slurry is determined by the change in the shape of the hemispherical droplet during the drying process.

According to the slurry management method of the present invention,
Whether the prepared slurry is suitable for obtaining spherical granules can be verified by simulation.

In the method of controlling the slurry, specifically, the extent to which the droplets are dented by the drying is used as a criterion for determining whether the particles are spherical or non-spherical. More specifically, it is determined that the granularity of the granules cannot be obtained when the droplets are dented by the drying, and the sphericity is obtained when the droplets are not dented.

3. Method for Producing Slurry In producing the slurry according to the present invention, the ratio (D / D0) of the average particle diameter D of the primary particles in a dispersed state of the particles and the average particle diameter D0 of the agglomerated particles due to the aggregation of the particles is used. The data showing the relationship between the degree of aggregation and the viscosity of the slurry are prepared.

Next, the concentration of particles in the solid-liquid dispersion system is
The spherical granule region and the non-spherical granule region obtained using the data are selected so as to fall within the spherical granule region.

According to the method for producing a slurry of the present invention, it is possible to maintain the dispersion state of particles, the realization of the particle state, and the dispersion state required for the production of granules which is the post-processing of the slurry. Moreover, the method for producing a slurry according to the present invention can be widely applied to a solid-liquid dispersion system which is a complex in which solid-liquid is mixed in various modes. Also, after-processing of the slurry,
Control parameters for each of the final products produced using the slurry can be controlled as a source of the properties of the slurry.

Data showing the relationship between the degree of cohesion (D / D0) and the viscosity of the slurry is collected by conducting an experiment for each particle material constituting the slurry. Collected aggregation degree (D / D0)
The data indicating the relationship between the slurry viscosity and the slurry viscosity can be stored in a computer and displayed as a graph on the computer display. The graph on this display shows spherical and non-spherical granular areas.

Therefore, the particle concentration or slurry viscosity in the target slurry is set so as to fall within the spherical granule region of the spherical granule region and the non-spherical granule region shown on the graph. This makes it possible to create spherical granules.

Data showing the relationship between the collected cohesion (D / D0) and the viscosity of the slurry may be graphed on a paper surface and used as a data sheet.

Although a duplicate description is omitted, the method for producing a slurry according to the present invention includes all the steps for obtaining the slurry according to the present invention described above.

Further, the production method according to the present invention may include a step of crushing the powder from the agglomerated state and then agitating to obtain floc-like or floc precursor aggregates. In this case, the stirring time can be adjusted to control the aggregation.

As another means, the solvent characteristics may be adjusted in order to obtain a floc-like or floc precursor aggregate after disintegrating the powder from the agglomerated state.

As yet another means, a step of adjusting the average particle size distribution of the particles is used in order to make the particles into floc-like or floc precursor aggregates after disintegrating the powder from the agglomerated state. You can also do it.

As yet another means, the ζ potential between the particles may be adjusted in order to obtain a floc-like or floc precursor aggregate after disintegrating the powder from the agglomerated state.

The properties of the slurry can be controlled by the degree of aggregation where the particles form a floc-like or floc precursor aggregate in the solvent. The properties of the slurry are
It may be controlled by at least one of the isoelectric point peculiar to the particles, the ζ potential (surface potential) of the interaction between the solvent and the powder, and the pH of the solvent.

4. Granules The granules according to the present invention are granulated from the above-mentioned slurry according to the present invention. The granules are spherical, flock-like,
Alternatively, an aggregate of floc precursors forms a skeleton inside.

The above-mentioned granules according to the present invention are dry-molded,
Used for injection molding, sheet molding, etc. Here, the granule according to the present invention has a spherical shape and is obtained by dry molding, injection molding, sheet molding or the like, because a floc-like or aggregated aggregate of floc precursors forms a skeleton inside. A product with excellent properties can be obtained as the final product.

In order to obtain solid spherical granules, the particles include fine particles and coarse particles, and the fine particles adhere to other fine particles or the coarse particles to form flock-like particles, or It is preferable that an aggregate of floc precursors is formed. Alternatively, the coarse particles may form a floc-like aggregate of the fine particles or an aggregate of floc precursors. In order to obtain solid spherical granules, it is preferable that the relative density difference between the fine particles and the coarse particles is small in the vicinity of the surface of the granules and in the vicinity of the center of the inside.

Having floc-like or aggregates of floc precursors aggregated with leaving voids, having coarse particles that become steric hindrance, or having floc-like or floc precursor aggregates that become steric hindrance, It is also an effective factor for obtaining solid spherical granules that a floc-like or aggregate of floc precursors aggregated in a specific shape is included and that the porosity is 35% or more. .

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION 1. Slurry In the slurry according to the present invention, solid component particles constitute a solid-liquid dispersion system in a liquid. When the average particle diameter of the primary particles in the dispersed state of the particles is D and the average particle diameter of the aggregated particles due to the aggregation of the particles is D0, the concentration of the particles is the degree of aggregation represented by (D / D0), and the slurry The spherical granule region and the non-spherical granule region obtained from the data showing the relationship with the viscosity are selected so as to fall within the spherical granule region.

Therefore, according to the slurry of the present invention,
Spherical granules can be reliably produced.

FIG. 1 is a graph showing the relationship between the degree of aggregation (D / D0) of primary particles and the viscosity of slurry. In the figure,
The horizontal axis shows the slurry viscosity (Ps), and the vertical axis shows the degree of aggregation of primary particles (D / D0).

The concentration is the volume concentration (v
ol%). The slurry contains a binder, a dispersant, a plasticizer, a defoaming agent, and the like, and may further contain an aggregating agent.

The characteristics A11 to A13 are the density a11 to a1.
The slurry viscosity-aggregation degree characteristic is shown with 3 (vol%) as a parameter. Concentrations a11 to a13 (vol%)
Becomes higher in the order of a11 <a12 <a13.

In FIG. 1, the shaded area is the spherical granule area S.
1 and the white region partitioned from the spherical granular region S1 by the straight line L0 indicates the non-spherical granular region S2. As shown in FIG. 1, in a slurry in which particles of a solid component form a solid-liquid dispersion system in a liquid, a graph obtained from experimental data showing the relationship between the agglomeration degree (D / D0) and the slurry viscosity is a spherical shape. The granule region S1 and the non-spherical granule region S2 are shown.

Referring to FIG. 1, density characteristics A11 to A1
No. 3 is in the non-spherical granular region S2 within the low viscosity,
It shows that the spherical granule region S1 is entered as the viscosity increases. Therefore, spherical granules can be obtained by using the graph shown in FIG. 1 and preparing a slurry whose concentration or viscosity falls within the spherical granule region S1.

More specifically, when the upper limit of viscosity required for the slurry is PS1 in a certain process, spherical granules can be obtained with a slurry having a concentration of a12 (vol%).

Assuming that a slurry having a concentration of a13 (vol%) is used, spherical granules can be obtained at any of the concentrations a13, a12 and a11 (vol%) if the viscosity is higher than PS2. it can.

As described above, the granules formed from the slurry according to the present invention are spherical and have a uniform density in the vicinity of the surface and inside and have a large number of pores, but a high density spherical shape. In other words, being spherical means having a high density,
It is nothing but a uniform granule.

FIG. 2 is a graph showing the relationship between the primary particle agglomeration degree (D / D0) and the slurry viscosity for the dielectric material. In the figure, the horizontal axis shows the slurry viscosity (Ps), and the vertical axis shows the degree of aggregation of primary particles (D / D0).

The dielectric material referred to herein is mainly composed of barium titanate, has a dielectric constant of 93 and a specific gravity of 5.8 (g / g).
cm ³ ), and the average particle size (D50) is 1.9 μm. The conditions for preparing the slurry and the method for measuring the physical properties of the slurry in this case are as follows. (A) PVA Polyvinyl alcohol (molecular weight 500) was used. (B) Additive Dispersant: Synthetic polycarboxylic acid NH ₄ salt Plasticizer: DEG (diethylene glycol) Defoamer: Octyl alcohol (c) Compounding ratio The following for 100 g of powder (primary dust) according to mass production conditions: PVA: 13 cc / powder 100 g Plasticizer: 1 cc / powder 100 g Defoaming agent: 1 cc / powder 100 g Dispersant: 0 to several cc / powder 100 g Pure water: balance (amount depends on concentration)

(D) Method for producing slurry Using a homogenizer, a solvent (water + PVA + plasticizer + defoaming agent) was first prepared, and powder was gradually added while stirring. A dispersant was added when the powder became insoluble or in order to achieve the desired viscosity. Agitation is 2000 r.
p. m for 5 to 30 minutes.

(E) Method for measuring physical properties of slurry The average particle diameter D of primary particles was measured by a laser diffraction particle size distribution analyzer (SALD-2100) manufactured by Shimadzu Corporation. In the measurement, dry powder of primary particles is 0.2 wt%
The mixture was diluted to a concentration of 1, the sodium hexametaphosphate dispersant was further added, and ultrasonic waves were irradiated for 10 minutes, and then the average particle size was measured.

Average particle size D0 of agglomerated particles due to agglomeration of particles
Is the value of the average particle size (D50) of the agglomerated particles obtained by measuring the average particle size of the agglomerated particles after slurrying with the laser diffraction type particle size distribution meter (SALD-2100) described above.
The slurry viscosity (Ps) was measured using a viscometer VM-10 manufactured by Rion Co., Ltd. and a B-type viscometer manufactured by Tokyo Koki Co., Ltd.

In FIG. 2, when the viscosity required for the slurry is lower than, for example, 1 (Ps), the concentration a12 =
Spherical granules cannot be obtained with a slurry of 30 (vol%) and a13 = 35 (vol%). To obtain spherical granules, a concentration of a11 = 25 (vol%) must be used.

Assuming that a slurry of concentration a13 = 35 (vol%) is used, if the viscosity is higher than 3 (Ps), the concentration a13 = 35 (vol%), a1
Spherical granules can be obtained in both cases of 2 = 30 (vol%) and a11 = 25 (vol%).

FIG. 3 is a graph showing the relationship between the degree of aggregation (D / D0) of primary particles and the viscosity of slurry for other dielectric materials. This graph was obtained by applying the same slurry preparation conditions and slurry physical property measuring methods as those in the graph shown in FIG. The dielectric material mentioned here has a specific gravity of 5 (g / cm ³ ) and an average particle size (D50) of 1.1 μm.
Is.

In FIG. 3, when the viscosity required for the slurry is lower than 1 (Ps), the concentration a11 =
20 (vol%), a12 = 25 (vol%), a13
= A12 = 30 (vol%) in any of the slurries, spherical granules can be obtained, but the concentration a14 = 35.
Spherical granules cannot be obtained with (vol%).

When using a slurry having a concentration a14 = 35 (vol%), if the viscosity is higher than 2 (Ps),
Spherical granules can be obtained. As a method of changing the viscosity under a constant concentration, in addition to adjusting the amount of the dispersant or coagulant added, the primary particle size of the powder and the p of the slurry are adjusted.
There is H adjustment etc.

As shown in FIGS. 2 and 3, the degree of aggregation (D
/ D0) and the viscosity of the slurry are different for each particle material contained in the slurry, but in any case, in the case of graphing, the spherical granular region S1 and the non-spherical granular region S2
Indicates. Therefore, by collecting experimentally the relationship data between the degree of aggregation (D / D0) and the viscosity of the slurry for each particle material contained in the slurry, a slurry suitable for obtaining spherical granules for each particle material can be obtained. Can be obtained.

In order to obtain high-density granules, it is necessary to increase the solid content (particle amount) of the slurry, but as is clear from the characteristics A11 to A14 of FIGS. It becomes difficult to make granules.

Further, the above method is applied to several kinds of materials,
By using the obtained high-density spherical granules, molding experiments in various products were tried, and it was confirmed that the variation in molding weight was reduced to 1/2 to 1/4.

The particles preferably form a floc-like or aggregate as a floc precursor in the liquid. A particularly preferable state of the aggregate is a state in which individual particles or aggregate particles are spontaneously dispersed and aggregated in a liquid. A slurry containing such aggregates is effective for obtaining solid spherical granules.

FIG. 4 is a diagram schematically showing a floc-like or floc precursor aggregate. The floc-like or floc precursor aggregate refers to an aggregated state in which the particles 1 and 2 are aggregated by a weak aggregation force. By the way, floc is generally defined as a cotton-like agglomerate having a high particle density due to an inorganic salt, an electrolyte, or a polymer coagulant, and the floc-like or floc precursor aggregate of the present invention is an additive. A state in which particles are gathered with a force weaker than the cohesive force of.

More preferably, the concentration of the powder in the slurry is set so as to be slightly above the concentration at which floc-like or floc precursor aggregates are not formed.
This makes it possible to reliably obtain spherical granules. This point can also be explained by using the graphs of FIGS. 1 to 3. That is, in FIG. 1 to FIG. 3, the intersection of the straight line L0, which is the boundary between the spherical granule region S1 and the non-spherical granule region S2, and the concentration characteristics A11 to A14 forms a floc-like or floc precursor aggregate. It can be regarded as a boundary point that is not to be prevented, and if the density is set to be slightly lower than this boundary point, it enters the spherical granule region S1.

As shown in FIG. 4, the particles include fine particles 1 and coarse particles 2, and the fine particles 1 are other fine particles 1 or coarse particles 2.
A slurry that adheres to and forms floc-like or floc precursor aggregates is also effective in producing solid spherical granules. Alternatively, the particles may be a floc-like in which coarse particles 2 collect fine particles 1 or a slurry in which aggregates of flock precursors are formed.

When the particles include fine particles 1 and coarse particles 2,
It is preferable that the fine particles 1 are mainly particles having an average particle diameter d1 of 1 micron or less, and the coarse particles 2 are mainly particles having an average particle diameter d2 of 1 micron or more.

Next, the relationship between the average particle size and the viscosity and the degree of aggregation will be described with reference to experimental data.

The viscosity and aggregation degree of the slurry were investigated at an average particle size of 1.6 μm to 2.2 μm. Results are shown in FIG. In FIG. 5, the horizontal axis represents the average particle size (μm), the left vertical axis represents the viscosity (PS), and the right vertical axis represents the cohesion degree. The characteristic L51 shows the viscosity characteristic, and the characteristic L51 shows the cohesion degree characteristic.

As shown in FIG. 5, the viscosity has an average particle size of 2.
Slurry using 2 μm primary particles is 1.6 μm
Although it was higher than that of the slurry using the primary particles of No. 1, the degree of agglomeration was conversely lower in the slurry using the primary particles of 2.2 μm.

From this fact, regarding the aggregation degree,
Since 1.6 μm, which is smaller than the layers, tends to aggregate,
It is considered that the aggregation degree was higher than 2.2 μm. Regarding the viscosity, the larger the one, the more hindered it becomes.
It is considered that the shear viscosity increased.

However, at the viscosity at which aggregation is more likely to occur, conversely, floc-like aggregates may form a larger steric hindrance. Therefore, similar experiments and evaluations are performed on primary particles having a particle size of 1 μm or less. went. The results are shown in Fig. 6.

In FIG. 6, the horizontal axis represents the average particle size (μm), the left vertical axis represents the viscosity (PS), and the right vertical axis represents the cohesion degree. The characteristic L61 shows the viscosity characteristic, and the characteristic L62 shows the cohesion degree characteristic.

In the experiment, the average particle size was
Two kinds of particles crushed to 0.789 μm and 1.741 μm were used, and 100: 0 and 50: 5, respectively.
Three kinds of samples were prepared by mixing in a ratio of 0: 0: 100.

With reference to FIG. 6, it can be seen that the viscosity increases as the particle size decreases, unlike the results for the particle size of 1.6 to 2.2 μm shown in FIG.
This means that there is an inflection point where the viscosity changes from a decreasing tendency to an increasing tendency between 0.8 μm and 1.6 μm. This is because the Brownian motion of the particles becomes large when the particle diameter is about 1 μm, and the cohesive force due to contact exceeds the peeling force of the particles due to stirring of the slurry, resulting in floc-shaped primary particles. This time, it is considered that the steric hindrance caused an increase in viscosity.

Combining FIGS. 5 and 6, from the viewpoint of viscosity, the particles should include fine particles 1 and coarse particles 2 (see FIG. 4).
It is understood that it is preferable that the fine particles 1 mainly have particles having an average particle diameter d1 of 1 micron or less, and the coarse particles 2 mainly have particles having an average particle diameter d2 of 1 micron or more.

The average particle diameter d1 of the fine particles 1 and the average diameter df of the aggregate preferably satisfy the following condition: 0.01 <d1 / df <1.0. When (d1 / df) is 1.0 or more, a sufficient amount of floc-like or floc precursor aggregates to produce spherical granules is obtained in the subsequent granulation step using the slurry. I will not be able to. On the other hand, if (d1 / df) is 0.01 or less, the floc-like or aggregate as the floc precursor becomes too large, and problems such as clogging of the pipe occur in the subsequent granulation step. Will end up.

The diameter df of the floc-like or aggregate of floc precursors is df with respect to the average particle diameter d2 of the coarse particles 2.
It is preferable that the relationship is ≧ d2. Furthermore, the diameter df of the floc-like or floc precursor aggregates
It is also effective to obtain solid spherical granules that df ≧ d2 is satisfied with respect to the average particle diameter d2 of the coarse particles 2. When the average particle diameter d2 of the coarse particles 2 becomes larger than the diameter df of the aggregate, coarse particles are included in the granules produced in the subsequent steps, resulting in uneven intragranular density or coarse particles in the slurry. There is a risk that the particles 2 will settle and the slurry concentration will vary.

The particle size distribution of the particles in the slurry is preferably a binomial distribution of fine particles 1 and coarse particles 2. The smaller the average particle size of the primary particles, the easier it is to form a floc-like or aggregate that serves as a floc precursor. Therefore, if the particle size distribution of the primary particles in the volume particle size distribution is set in advance so as to have an appropriate binomial distribution, a floc-like or floc precursor aggregate can be made more easily.

Since the fine particles 1 mixed in the liquid of the slurry have a smaller weight than the coarse particles 2, they are easily moved in the liquid (easy movement state), and the fine particles 1 contact each other in the liquid or are coarse. The particles 2 and the fine particles 1 are in contact with each other with the coarse particles 2 as a core, and the fine particles 1 or the coarse particles 2 and the fine particles 1 are aggregated by a suction force or an adsorption force to form a floc-like or floc precursor aggregate. The body is formed and it becomes difficult to move.

Since the floc-like or floc precursor aggregates and coarse particles 2 act as steric hindrances to the fine particles 1 in the liquid, once the floc-like or floc precursors are locally generated. When the aggregate is formed in the liquid, new fine particles 1 are further aggregated around the floc-like or floc precursor aggregate, and the floc-like or floc precursor aggregate is Grows large and the steric hindrance progresses.

At this time, since the floc-like or floc precursor aggregates themselves are not so strong in binding force, they may be repeatedly aggregated. Then, in the slurry as a solid-liquid dispersion system, floc-like or aggregates of floc precursors have an appropriate size in equilibrium, which reduces the number of independent fine particles 1 in the liquid. The movement of the fine particles 1 is suppressed. As a result, the floc-like or floc precursor aggregate functions to make the solid-liquid dispersion state of the slurry uniform.

In the slurry of the present invention, the fine particles 1 or floc precursor aggregates act as steric hindrance in the liquid, so that the fine particles 1 and the coarse particles 2 are unevenly distributed in the slurry. It prevents sedimentation and separation and maintains a slurry state in which a solid liquid is dispersed for a long period of time.

When the slurry of the present invention is used to obtain an agglomerated body such as granules or green sheets, fine particles 1 in the liquid are floc-like or in the process of drying and reducing the liquid phase component. , That the aggregates of the floc precursors are aggregated and restrained, and that the aggregates of the floc precursors or the floc precursors cause steric hindrance and the fine particles 1 move from the inside of the vaginal form to the surface. Since it is hindered, it works to prevent only the fine particles 1 from collecting on the surface of the vaginal form. As a result, so-called "skinning" does not occur in the vaginal form.

During the process in which the liquid phase components contained in the floc-like or floc precursor aggregates decrease, the aggregates of fine grains 1 and coarse grains 2 form a skeleton, so A sparse vaginal form will be formed over. For this reason, the liquid phase component inside the axillary body is likely to come out to the surface through the voids of the skeleton, so that the liquid phase component is not left inside the axillary body and the solid liquid The dispersed state becomes homogeneous.

Further, the slurry according to the present invention can contain the second fine particles. The second fine particles are changed from the easy-moving state in which the fine particles 1 easily move in the liquid to the hard-moving state in which the fine particles 1 are hard to move by forming floc-like or floc precursor aggregates. Change the mobility to increase the viscosity of the slurry.

In the field of fine ceramics, which is the main application area of the invention, the slurry contains a binder.
This slurry may be an aqueous solution containing no coagulant or a slurry containing no dispersant. On the contrary, a minute amount of the dispersant may be contained. Further, it may contain a water-releasing additive.

In the field of fine ceramics, even if the viscosity of the slurry and the concentration of the ceramic powder are selected so as to fall within the spherical granule region, the amount of the binder and the concentration of the ceramic powder will be increased if stirring is continued for a long time. In some cases, it may enter the non-spherical granular region from the spherical granular region.

This problem is that it has at least one hydroxyl group and is selected from the group consisting of carboxyl group, carboxylate, sulfonic acid, sulfonate, phosphoric acid, phosphate, amine, and quaternary amine salt. It is solved by adding a non-polymeric organic compound having a functional group.

Examples of the organic compound include hydroxyl group-containing carboxylic acid, hydroxyl group-containing carboxylate, hydroxyl group-containing sulfonic acid, hydroxyl group-containing sulfonate, hydroxyl group-containing phosphoric acid,
It may be selected from the group consisting of hydroxyl group-containing phosphates, hydroxyl group-containing amines, and hydroxyl group-containing quaternary ammonium salts.
More specifically, this organic compound is selected from the group consisting of citric acid, meso-tartaric acid, hydroxyl-containing lower carboxylic acid, hydroxyl-containing lower alkenylcarboxylic acid, hydroxyl-containing lower alkynylcarboxylic acid, hydroxyl-containing aromatic carboxylic acid, and combinations thereof. Can be selected.

The case where citric acid is used as an additive will be described below as an example. FIG. 7 shows citric acid (1 mol /
It is a figure which shows a viscosity-aggregation degree characteristic when not adding (1 aqueous solution) (0 ml). PVA amount is 0wt%, 0.5wt
%, 1.0 wt%, 1.5 wt%, 2.34 wt% 5
Changed in stages. In each amount of PVA, the characteristic indicated by the solid line of the double-headed arrow is the initial viscosity-cohesion degree characteristic when the concentration of the ceramic powder in the slurry is changed in the range of 25 vol% to 34 vol%. The straight line L0 indicates the boundary between the spherical granular region S1 and the non-spherical granular region S2. The straight-line dotted arrows L71 to L74 indicate a long time (for example, about 2
PVA with continuous stirring for 4 hours)
The viscosity-coagulation degree changing direction and the magnitude of the change are shown for each amount. The direction of change in viscosity-cohesion is indicated by the dotted arrow L71.
~ L74 orientation and magnitude of change is indicated by the length of the dotted line. This principle is shown in FIGS.
The same applies to the above.

First, as shown in FIG. 7, as the amount of PVA increases, both the viscosity and the degree of aggregation decrease. This is a common phenomenon in this type of slurry.

With the citric acid-free slurry of FIG.
If the PVA amount is in the range of 0.5 to 1.5 wt%, the spherical granule region S1 is entered in the whole range of the ceramic powder concentration of 25 vov to 34 vol%. However, when the stirring is continued for a long time (for example, 24 hours), the viscosity-cohesion degree characteristics decrease in both the viscosity and the cohesion degree as shown by a dotted arrow L72, and the spherical granule region S1 and the non-spherical granule region S2 are formed. Changes to a direction approaching the straight line L0 indicating the boundary of.
Moreover, the changes in viscosity and cohesion are very large.

When the amount of PVA is 1.5 wt%, 25v
The initial viscosity-cohesion degree characteristic when changing in the range of ol% to 34 vol% shows that a part of the intermediate portion is a non-spherical granular region S.
When 2 is entered and stirring is continued for a long time, the viscosity-cohesion degree property changes in a direction in which both the viscosity and the cohesion degree decrease, as indicated by the dotted arrow L73, and enters the non-spherical granule region S2 as a whole. Go.

When the amount of PVA is 2.34 wt%, 25
The initial viscosity-cohesion degree characteristics when changing in the range of vol% to 34 vol% fall entirely within the non-spherical granular region S2.

When the amount of PVA is small, the granules granulated from this slurry become brittle. Therefore, in order to avoid this, the amount of PVA should be set to about 1 wt% to 3 wt%. Is preferred. However, in the slurry containing no citric acid, as shown in FIG.
In the range where the VA amount is 1.5 wt% to 2.34 wt%,
Since the initial value may fall within the non-spherical granular region S2, it is difficult to use.

FIG. 8 is a diagram showing the viscosity-cohesion degree characteristics when the content of citric acid is 0.5 ml. The content of the amount of PVA was changed in 5 stages as shown in FIG. 7.
For each amount of PVA, the characteristic indicated by the solid line with double-headed arrow indicates the concentration of the ceramic powder in the slurry at 25 vol.
It is an initial viscosity-aggregation degree characteristic when it changes in the range of% -34vol%. The straight line L0 indicates the boundary between the spherical granular region S1 and the non-spherical granular region S2. Dotted arrow L81
Indicates the direction of change in viscosity-cohesion degree when a slurry having a PVA amount of 2.34 wt% and a ceramic powder concentration of 34 vol% is continuously stirred for a long time, and a dotted arrow L82 indicates a PVA amount of 2 The viscosity-coagulation degree change direction is shown when the slurry having a ceramic powder concentration of 0.34 wt% and a ceramic powder concentration of about 30 vol% is continuously stirred for a long time.

When the content of citric acid is 0.5 ml, P
In any case where the amount of VA is 0.5 to 2.34 wt%, the initial viscosity-cohesion degree characteristic falls within the spherical granular region S1 in the entire range of the concentration of ceramic powder 25 vov to 34 vol%.

In the case of a slurry having a PVA content of 2.34 wt%, when the stirring is continued for a long time (for example, 24 hours), the viscosity-cohesion degree characteristic shows that the viscosity and the cohesion degree are as shown by dotted arrows L81 and L82. Both decrease and change toward the non-spherical granule region S2, but the amount of change is smaller than that in the case of FIG.

Moreover, in the dotted line arrows L81 and L82, the change amount of the cohesion degree with respect to the change amount of the viscosity is smaller than that in the case of the dotted line arrows L72 to L74 in FIG. 7 (the arrow direction is rising). There is a tendency.

FIG. 9 is a diagram showing the viscosity-cohesion degree characteristic when the content of citric acid is 2.5 ml. The content of the amount of PVA was changed in 5 stages as shown in FIG. 7.
For each amount of PVA, the characteristic indicated by the solid line with double-headed arrow indicates the concentration of the ceramic powder in the slurry at 25 vol.
It is an initial viscosity-aggregation degree characteristic when it changes in the range of% -34vol%. The dotted arrow L91 indicates the PVA amount of 2.3.
The direction of change in viscosity-cohesion degree is shown when a slurry having a concentration of 4 wt% and a ceramic powder concentration of 25 vol% is stirred for a long time.

When the content of citric acid is 2.5 ml, P
In any case where the amount of VA is 0.5 to 2.34 wt%, the initial viscosity-cohesion degree characteristic falls within the spherical granular region S1 in the entire range of the concentration of ceramic powder 25 vov to 34 vol%. That is, spherical granules are easier to produce than the example of FIG. 7 containing no citric acid. However, the viscosity is preferably 3 (Ps) or less in order to prevent tube clogging in the mass production process. From that point of view, a slurry having a PVA amount of 0.5 to 1.0 wt% with a viscosity exceeding 3 (Ps) is not suitable for mass production.

A slurry having a PVA content of 1.5 wt% to 2.3 wt% has an initial viscosity-cohesion degree characteristic in the range of ceramic powder concentration of 25 vol% to about 28 vol%.
Enter the spherical granule region S1. That is, compared to the example of FIG. 7 containing no citric acid and the example of FIG. 8 containing 0.5 ml of citric acid,
It is easy to make spherical granules.

In the case of a slurry having a PVA content of 2.34 wt%, the viscosity-aggregation degree characteristic tends to decrease with agitation for a long time while maintaining a substantially constant viscosity as indicated by a dotted arrow L91. Although it changes, the amount of change is smaller than in the cases of FIGS. 7 and 8.

In addition, the direction of change indicated by the dotted arrow L91 is such that the amount of change in the cohesion degree with respect to the amount of change in viscosity is smaller than in the case of the dotted arrows L81 and L82 in FIG. The tendency is shown.

FIG. 10 is a diagram showing the viscosity-cohesion degree characteristic when the content of citric acid is 5 ml. The content of the amount of PVA was changed in 5 stages as shown in FIG. 7. P
In each amount of VA, the characteristic indicated by the solid line of the double-sided arrow indicates the concentration of the ceramic powder in the slurry by 25 vol%.
It is an initial viscosity-aggregation degree characteristic when changed in the range of up to 34 vol%. The dotted arrow L101 indicates the PVA amount of 2.3.
4wt% and ceramic powder concentration 25vol
% Shows the direction of change in viscosity-cohesion degree when the slurry in% is stirred for a long time.

When the content of citric acid is 5 ml, PVA
In any case where the amount is 0.5 to 2.34 wt%, the initial viscosity-cohesion degree characteristic falls within the spherical granular region S1 in the whole range of the concentration of the ceramic powder of 25 vov to 34 vol%. That is, spherical granules are easier to produce than the example of FIG. 7 containing no citric acid. A slurry having a viscosity exceeding 3 (Ps) and having a PVA amount of 0.5 wt% or more and less than 1.0 wt% is not suitable for mass production.

The slurry having a PVA content of 1.5 wt% to 2.3 wt% has an initial viscosity-cohesion degree characteristic in the range of ceramic powder concentration of 25 vol% to about 28 vol%.
Enter the spherical granule region S1. That is, compared to the example of FIG. 7 containing no citric acid and the example of FIG. 8 containing 0.5 ml of citric acid,
It is easy to make spherical granules.

In the case of a slurry having an amount of PVA of 2.34 wt%, the change in the viscosity-coagulation property due to stirring is indicated by a dotted arrow L.
As indicated by reference numeral 101, the degree of aggregation tends to decrease while maintaining a substantially constant viscosity.
It is smaller than the case. Moreover, in the change direction indicated by the dotted arrow L101, the amount of change in the degree of aggregation with respect to the amount of change in viscosity is smaller than in the case of the dotted arrows L81 and L82 in FIG. 8 (the arrow direction is rising). Shows a trend.

FIG. 11 is a graph showing a change tendency of the viscosity-cohesion degree characteristic when the ratio of citric acid and PVA is changed. The characteristics shown in FIG. 11 can be read from the characteristic diagrams shown in FIGS. 7 to 10, but FIG. 11 is shown for understanding.

The straight arrows L111 to L116 indicate the viscosity-coagulation degree changing direction when the slurry with the PVA amount and the ceramic powder concentration being constant and the citric acid amount being changed was stirred.

As shown in FIG. 11, as the (citric acid / PVA) ratio increases (citric acid increase), the rate of change in the degree of cohesion with respect to the change in viscosity becomes smaller and enters the non-spherical granular region S2. It shows that it becomes difficult. That is, by controlling the content of citric acid,
Despite stirring, it becomes possible to stably produce spherical granules.

The reason why the slurry in the spherical granule region S1 comes into the non-spherical granule region S2 when the slurry is stirred and the reason why this problem can be solved by containing citric acid is as follows. By speculation, it can be explained as follows.

Considering the initial state before stirring of the slurry containing the ceramic powder, water, PVA and the dispersant, PVA is adsorbed on the particles constituting the ceramic powder. Since lone electron pairs (loan pairs) of oxygen atoms are present on the surface of the oxide ceramic particles, the PVA attached to the ceramic particles and each other of the ceramic particles repel each other and are released by an electric repulsive force. This electric repulsive force affects the viscosity and the degree of cohesion.

On the other hand, PVA releases protons (H ⁺ ). The release of this proton (H ⁺ ) changes (decreases) the pH of the slurry. Changes in pH also affect viscosity and degree of aggregation.

In the initial state of the slurry prepared according to the present invention, the viscosity and the degree of aggregation influenced by the above-mentioned repulsive force, pH, etc., and further the concentration are already set in the spherical granular region. As stated.

When the slurry system initialized as described above is stirred for a long period of time, among the protons (H ⁺ ) existing in the slurry, those adsorbed to oxygen around the ceramic powder slightly increase. For this reason, the pH of the slurry rises, though it is very small, and the viscosity and the degree of aggregation are lowered.

As a result, as shown in FIGS. 7 to 10,
In the initial state, the slurry suitable for the spherical granule region S1 is
It is presumed that the agitated particles enter the non-spherical granular region S2.

On the other hand, when citric acid was added to the slurry containing the ceramic powder, water, PVA and the dispersant,
Citric acid has (-C00H) and releases a large amount of protons (H ⁺ ). Therefore, the pH of the slurry decreases and the viscosity increases.

On the other hand, the released protons (H ⁺ ) are
In preference to VA, it is adsorbed around the ceramic particles constituting the ceramic powder, and the function of aggregating the ceramic particles occurs due to hydrogen bonding. That is, the action of reducing the particle dispersion effect due to the adsorption of PVA on the ceramic particles occurs.

That is, by containing citric acid, the viscosity of the slurry and the degree of aggregation are increased. This means that in the viscosity-cohesion degree characteristics shown in FIGS. 1 to 10, the change over time indicated by the dotted arrow is canceled out.

Therefore, it is presumed that, by adding citric acid, the action and effect of retaining the citric acid in the spherical granular region S1 can be obtained despite the stirring.

The meaning of containing citric acid is to release a large amount of protons (H ⁺ ), and p
If it is to stabilize the H buffer effect, that is, to stabilize the amount of protons (H ⁺ ) in the liquid, it is obvious that any organic compound having a similar function can be used instead of citric acid. . The organic compounds mentioned above are examples. Also,
It can be considered that the above description of the slurry containing PVA is appropriate because no significant change with time is observed in the slurry containing only ceramic powder and water.

Next, when a plurality of types of ceramic powders having the same composition and the same manufacturing process but different manufacturing lots are used, as shown in FIG. 12, a slurry P1 using the ceramic powder of a certain lot is used. Then the spherical granule area S1
However, the slurry P2 containing the ceramic powder of another lot may enter the non-spherical granular region S2.

In order to solve this problem, it is extremely effective to add an alkali to the slurry. Specific examples thereof include ammonia, sodium hydroxide, sodium carbonate, sodium hydrogen carbonate and the like.

The function and effect of the addition of alkali can be explained as follows with reference to FIG. 13 is p
It is a figure which shows the relationship between H, viscosity (refer left vertical scale), and zeta potential (right vertical scale). Curve L131
Is the pH-viscosity characteristic of the slurry before addition of alkali, curve L
Reference numeral 132 represents the pH-zeta potential characteristic before addition of alkali, curve L133 represents the pH-viscosity characteristic of the slurry after addition of alkali, and curve L134 represents the pH-zeta potential characteristic after addition of alkali.

First, the pH-viscosity characteristic L131 and the pH-zeta potential characteristic L132 of the slurry before alkali addition will be examined. As the pH becomes lower, the zeta potential approaches the equipotential point and the viscosity becomes higher.
Although the degree of cohesion is not shown, it changes substantially in proportion to the viscosity. This is because as the pH decreases, the zeta potential due to the electric double layer formed on the surface of the ceramic particles in the slurry decreases, and toward the equipotential point ζ01, the repulsive force acting between the ceramic particles decreases and the particles agglomerate. It is presumed that it will be easier. The agglomeration is maximum at the equipotential point ζ01 where the repulsive force acting between the ceramic particles becomes almost zero.

On the other hand, when the pH is high, the zeta potential is also high and the viscosity is low. This is presumed to be because as the pH increases, the zeta potential of the ceramic particles in the slurry increases, the repulsive force acting between the ceramic particles increases, and the particles easily disperse.

When alkali is added to the slurry in the initial state as shown in FIG. 13, the pH becomes high. P in FIG.
From the H-viscosity characteristic L131 and the pH-zeta potential characteristic L132, it becomes easier to disperse as the pH becomes higher,
It also seems to reduce viscosity and cohesion.

However, in reality, the addition of alkali increases the viscosity and the degree of coagulation, and as shown in FIG. 12, the slurry P2 contained in the non-spherical granular region S2 becomes
It was confirmed to enter the spherical granule region S1.

The reason for this is unconfirmed, but the equipotential point ζ01 of the initial zeta potential moves to the equipotential point ζ02 by the addition of alkali, and the initial pH-viscosity characteristic L131 and pH-zeta potential characteristic L132. But arrows b1 and c
It is presumed that it may be because of the shift as shown by 1 and the pH-viscosity characteristic L133 and the pH-zeta potential characteristic L134.

2. Slurry management method When evaluating granules, conventionally, there is only a method to confirm the granules obtained by a spray dryer. Therefore, in examining the slurry conditions, a great deal of labor, time,
Material was needed.

In the slurry management method of the present invention, the slurry is dropped on a flat resin surface to form hemispherical drops. Next, the droplet is heated to reduce the content of the liquid phase component, and the property of the slurry is determined by the change in the shape of the hemispherical droplet during the drying process.

According to the slurry management method of the present invention,
Whether the prepared slurry is suitable for obtaining spherical granules can be verified by simulation. The slurry management method according to the present invention is also an extremely effective means for collecting data shown in FIGS.

In the slurry management method according to the present invention, specifically, the extent to which the droplets are dented by drying is used as a criterion for determining whether the granules are spherical or non-spherical. More specifically, it is determined that if the droplets are dented by drying, the sphericalness of the granules cannot be obtained, and if the droplets are not dented, the sphericalness is obtained.

FIG. 14 shows a specific example of the slurry management method. First, as shown in FIG. 14A, the slurry is dropped onto the silicone sheet 31 to a size of, for example, about 500 μm by using the dispenser 32, and the droplet 3
3 is formed. Since the size of the droplet 33 affects the detection sensitivity, it is preferable to define it in advance.

Next, as shown in FIG. 14B, 1 Os
It is put into a dryer 34 at 150 ° C. within ec to dry the droplet 33. The temperature conditions and the like are appropriately determined according to the granulation conditions.

Next, as shown in FIG. 14C, the dryer 3
Looking at the shape of the dried product of the hemispherical droplet 33 when taken out from FIG. 4, it is depressed (FIG. 14 (C1)) or spherical (FIG.
2) Determine if The granule shape obtained by this method is in good agreement with the granule shape after spray drying.

As the silicone sheet, Sarcon (registered trademark) manufactured by Fuji Polymer Co., Ltd. is suitable. This silicone sheet is kneaded with an inorganic filler, so that the contact angle when the slurry is dropped becomes large. Therefore, the shape of the granules produced by the spray dryer can be approximated.

[0140]

As described above, according to the present invention,
Slurry suitable for producing spherical granules, slurry management method,
A method of manufacturing a slurry can be provided.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the degree of aggregation (D / D0) of primary particles and the viscosity of slurry.

FIG. 2 shows the degree of aggregation (D / D) of primary particles for dielectric materials.
It is a graph which shows the relationship between 0) and slurry viscosity.

FIG. 3 shows the degree of aggregation (D) of primary particles for other dielectric materials.
7 is a graph showing the relationship between / D0) and the viscosity of slurry.

FIG. 4 is a diagram schematically showing a floc-like or floc precursor aggregate.

FIG. 5 is a diagram showing a relationship among an average particle diameter (μm), a viscosity (PS) and a cohesion degree of a dielectric material.

FIG. 6 is a diagram showing another relationship between the average particle diameter (μm), the viscosity (PS), and the cohesion degree of the dielectric material.

FIG. 7: Viscosity when citric acid is not added (0 ml)-
It is a figure which shows a cohesion degree characteristic.

FIG. 8 is a diagram showing viscosity-cohesion degree characteristics when the content of citric acid is 0.5 ml.

FIG. 9 is a diagram showing viscosity-cohesion degree characteristics when the content of citric acid is 2.5 ml.

FIG. 10 is a diagram showing viscosity-cohesion degree characteristics when the content of citric acid is 5 ml.

FIG. 11 is a diagram showing a change tendency of viscosity-cohesion degree characteristics when the ratio of citric acid and PVA is changed.

FIG. 12 is a diagram showing viscosity-cohesion degree characteristics of a slurry when a plurality of types of ceramic powders manufactured in different production lots are used.

FIG. 13 is a diagram showing the relationship between pH, viscosity, and zeta potential.

FIG. 14 is a diagram showing a specific example of a slurry management method according to the present invention.

[Explanation of symbols]

S1 Spherical granule region S2 Non-spherical granule region A11 to A13 Viscosity-cohesion degree characteristic with concentration as a parameter

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Koji Tashiro             1-13-1, Nihonbashi, Chuo-ku, Tokyo             -In DC Inc. F-term (reference) 4G004 AA02                 4G065 AA01 AA06 AA07 AA10 AB03X                       AB11X AB11Y AB14Y AB17X                       AB22X AB25X BA07 BB01                       BB03 CA12 DA05 DA06 DA09                       DA10 EA03 EA04 EA10 FA10

Claims (31)

[Claims] 1. A slurry in which particles of a solid component form a solid-liquid dispersion system in a liquid, wherein the concentration of the particles in the solid-liquid dispersion system and the slurry viscosity are primary particles in a dispersed state of the particles. Where D is the average particle size of D, and D0 is the average particle size of the agglomerated particles resulting from the agglomeration of the particles, it is obtained from the data showing the relationship between the degree of aggregation represented by (D / D0) and the slurry viscosity. A slurry selected to fall within the spherical granule region of the spherical granule region and the non-spherical granule region. 2. The slurry according to claim 1, wherein the particles form a floc-like or aggregate as a floc precursor in a liquid. 3. The slurry according to claim 2, wherein the aggregate is a state in which individual particles or aggregate particles are spontaneously dispersed and aggregated in a liquid. 4. The slurry according to claim 1, wherein the particles include fine particles and coarse particles, and the fine particles are other fine particles or the coarse particles. A slurry that adheres to the grains to form floc-like or floc precursor aggregates. 5. The slurry according to claim 4, wherein the fine particles are mainly particles having an average particle size of 1 micron or less, and the coarse particles are mainly particles having an average particle size of 1 micron or more. Slurry. 6. The slurry according to claim 4, wherein when the average particle diameter of the fine particles is d1 and the average diameter of the aggregate is df, 0.01 <d1 / df < A slurry that satisfies 1.0. 7. The slurry according to any one of claims 4 to 6, wherein the particle size distribution of the particles is a binomial distribution of the fine particles and the coarse particles. 8. The slurry according to any one of claims 2 to 7, comprising coarse particles that cause steric hindrance, or floc-like or floc precursor aggregates that cause steric hindrance. 9. The slurry according to claim 1, which is an aqueous solution containing a binder. 10. The slurry according to claim 1, which does not contain a dispersant. 11. The slurry according to claim 1, which contains a trace amount of a dispersant. 12. The slurry according to any one of claims 1 to 10, wherein the slurry contains a sustained water release additive. 13. The slurry according to claim 1, comprising at least one hydroxyl group and a carboxyl group,
A slurry containing at least one organic compound selected from the group consisting of carboxylates, sulfonic acids, sulfonates, phosphoric acids, phosphates, amines, and quaternary amine salts. 14. The slurry according to claim 13, wherein the organic compound is a hydroxyl group-containing carboxylic acid, a hydroxyl group-containing carboxylate, a hydroxyl group-containing sulfonic acid, a hydroxyl group-containing sulfonate, a hydroxyl group-containing phosphoric acid, and a hydroxyl group-containing compound. A slurry containing at least one selected from the group consisting of a phosphate, a hydroxyl group-containing amine, and a hydroxyl group-containing quaternary ammonium salt. 15. The slurry according to claim 13, wherein the organic compound is citric acid, meso-tartaric acid, hydroxyl group-containing lower carboxylic acid, hydroxyl group-containing lower alkenylcarboxylic acid, hydroxyl group-containing lower alkynylcarboxylic acid, hydroxyl group-containing. A slurry containing at least one selected from the group consisting of aromatic carboxylic acids and combinations thereof. 16. The slurry according to claim 1, wherein the slurry contains an alkali. 17. The slurry according to claim 16, wherein the alkali contains at least one of ammonia, sodium hydroxide, sodium carbonate, and sodium hydrogencarbonate. 18. A method for producing a slurry, wherein particles of a solid component form a solid-liquid dispersion system in a liquid, wherein an average particle diameter of primary particles in a dispersed state of the particles is D, and aggregation by aggregation of the particles. When the average particle size of the particles is D0, data showing the relationship between the degree of aggregation represented by (D / D0) and the slurry viscosity is prepared, and the concentration of the particles in the solid-liquid dispersion system or the slurry viscosity is prepared. Of the spherical granule region and the non-spherical granule region obtained from the data showing the relationship between the agglomeration degree (D / D0) and the slurry viscosity so as to fall within the spherical granule region. Manufacturing method. 19. The method for producing a slurry according to claim 18, wherein the powder is crushed from a state of being aggregated, and then stirred to form floc-like or floc precursor aggregates. Method for producing slurry. 20. The method for producing a slurry according to claim 18, wherein the stirring time is adjusted to control the aggregation. 21. The method for producing a slurry according to any one of claims 18 to 20, wherein the powder is crushed from an agglomerated state and then formed into floc-like or floc precursor aggregates. In order to achieve the above, a method for producing a slurry in which solvent characteristics are adjusted. 22. The method for producing a slurry according to claim 18, wherein the powder is crushed from an agglomerated state and then formed into floc-like or floc precursor aggregates. In order to achieve the above, a method for producing a slurry, wherein the average particle size distribution of the particles is adjusted. 23. The method for producing a slurry according to any one of claims 18 to 22, wherein after the powder is crushed from an agglomerated state, a floc-like or floc precursor aggregate is formed. In order to achieve the above, a method for producing a slurry for adjusting the ζ potential between the particles. 24. The method for producing a slurry according to any one of claims 18 to 23, wherein the properties of the slurry are such that the particles form a floc-like form in a solvent or an aggregate of flock precursors. Method of controlling slurry by controlling the degree of coagulation. 25. The method for producing a slurry according to claim 18, wherein the properties of the slurry are the isoelectric point peculiar to the particles and the ζ potential (surface of the interaction between the solvent and the powder). Potential) and at least one of the pH of the solvent. 26. A method for controlling a slurry, wherein particles of a solid component form a solid-liquid dispersion system in a liquid, wherein the slurry is dropped on a flat resin surface to form a hemispherical droplet. A method comprising the steps of heating the droplets to reduce the content of the liquid phase and determining the properties of the slurry by changing the shape of the hemispherical droplets during the drying process. 27. The slurry management method according to claim 26, wherein the extent to which the droplets are dented by the drying is used as a criterion for determining whether the particles are spherical or non-spherical. . 28. The method of controlling a slurry according to claim 27, wherein if the droplets are dented by the drying, the sphericity of the granules cannot be obtained, and if they are not dented, the sphericity is obtained. How to judge. 29. Granules granulated from a slurry, comprising:
Granules that are spherical and have a floc-like or aggregate of floc precursors forming a skeleton inside. 30. The granule according to claim 29, wherein the inside is solid. 31. The granule according to claim 29 or 30, wherein the granule has an opening open to the outside, and the opening extends to the inside.