JP2010000414A - Filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter for eliminating foreign matter contained in slurry suspended with solid matter consisting of fine particles, and providing high quality slurry having solid matter consisting of only object fine particles. <P>SOLUTION: In the filter, a filter element is fixed in a sealed filter housing 1, the filter housing is split into two chambers, a treating object slurry feed port is provided to one chamber and a treated slurry discharge port is provided to the other chamber. The sealed filter housing has a vibration device attached to an outer wall thereof, and is vibratably attached to a fixing stand 5 by a support mechanism. Flexible pipes 3a, 4a are connected to the treating object slurry feed port and treated slurry discharge port to supply the treating object slurry and discharge the treated slurry. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a novel filtration device. Specifically, the present invention provides a filtration device for removing foreign matters contained in a slurry in which a solid content composed of fine particles is suspended and obtaining a high-quality slurry having a solid content composed only of the fine particles.

  Here, examples of the foreign matter include aggregated particles, coarse foreign matter that has entered from outside the system, and coarse particles such as a gel-like substance that remains in a gel state due to insufficient dissolution.

  Generally, an operation of passing a slurry in which a solid content is suspended through a filter element (filter medium) to remove foreign matters contained in the fluid is often performed. For example, in the manufacture of a sintered body of aluminum nitride, the slurry is filtered by a filtration device as a treatment of a slurry containing aluminum nitride powder, an organic binder, and an organic solvent, which is used when manufacturing a green body. Thus, an operation of removing coarse particles mixed as foreign matters is performed.

  The filtration operation is very dependent on the properties of the solids dispersed in the fluid to be treated. That is, a slurry containing fine particles of 20 μm or less is concentrated and loses fluidity when it becomes a high concentration such as a cake and behaves like a solid, but liquefies when given vibration (this property is called thixotropic property). ). In this way, when the slurry is filtered in order to remove foreign substances contained in the thixotropic slurry, the slurry is concentrated on the surface of the filter medium due to the filtration resistance of the filter element. As a result, the cake accumulates and grows on the surface of the filter element, and the filtration resistance rapidly increases and finally becomes unfilterable.

  Conventionally, in order to filter a slurry having such thixotropic properties, it has been necessary to dilute the slurry or to force the filtration by applying a high pressure.

  However, these means are disadvantageous in that the apparatus is large, the power cost is high, and the efficiency is low. In addition, it was difficult to perform a large amount of processing at once. Furthermore, it is necessary to dismantle the apparatus and clean or replace the filter element during the filtration, and the filtration cannot be performed continuously for a long period of time.

  In recent years, in order to solve the above problems, a filtering device has been proposed in which a solid is not deposited on the surface of the filter element by rotating the filter element in the filter housing or circulating the liquid to be treated (patent). References 1 and 2).

  However, when the above filtration device uses a filter element surface or a volume filtration type filter element, solid content adheres to the inside of the filter element, and once solidified, it can be removed to recover the filtration capacity. In the same manner as the filtration device, it was necessary to dismantle the device and clean or replace the filter element. In addition, the power to circulate the liquid to be processed and the filter to rotate is large, and depending on the properties of the liquid to be processed, the seal part of the pump and rotary shaft wears, so a special design with high accuracy is required. Since it is difficult to minimize wear, it is unsuitable for use in obtaining a high-quality slurry by filtering a slurry containing ceramics.

  On the other hand, an ultrasonic irradiation device is installed in the filtration chamber to irradiate the supplied slurry with ultrasonic waves, thereby preventing particle aggregation and redispersing the slurry that behaves as a solid deposited on the filter element surface. An ultrasonic filtration device that fluidizes and performs filtration is disclosed (see Patent Document 3). However, this apparatus is not only expensive, but also requires a lot of labor for the cleaning work when changing lots. In addition, when the solvent used is dangerous, it is substantially difficult to use.

  The above filtration device performs continuous and stable filtration for a long period of time without causing clogging in the case of using a surface filtration type filter element even in the filtration of a slurry whose concentrate has thixotropy. be able to. However, when a volume filtration type filter element is used, it is difficult to ensure sufficient fluidization because ultrasonic waves do not reach the treated slurry solidified inside the filter element.

  In addition, in order to prevent clogging of the filter element, the filter housing and the vibration device are connected by a shaft passing through the side wall of the filter housing, and the filter element is directly vibrated to thereby prevent the cake from adhering and growing on the filter medium surface. A prevention method is also conceivable.

  However, when a structure in which the filter element is vibrated through the shaft as described above is employed, such a filter device has a sliding portion where the shaft penetrates the wall of the filter housing structurally. Filtration of a slurry containing fine particles having a high particle size has a problem that the sliding portion is worn, and wear powder is mixed in the slurry that has been subjected to the filtration treatment to deteriorate the quality of the slurry.

  Therefore, such a filtration device can be used for waste liquid treatment or for applications that do not require the purity of the collected filtrate, but such a slurry that is extremely hated to be contaminated with impurities, such as a slurry for producing a green body of aluminum nitride. The present situation is that it cannot be used for the purification of sucrose.

JP-A-6-91201 Japanese Patent No. 3758371 JP 2006-247484 A

  Accordingly, an object of the present invention is to stably perform filtration while preventing clogging in the filter element in the filtration apparatus for filtering the slurry, and reliably prevent contamination of the obtained treated slurry. An object of the present invention is to provide a simple filtration device that can be used.

The inventors of the present invention have made extensive studies to solve the above-mentioned object. As a result, if the filter element is fixedly provided in the hermetic filter housing and the hermetic filter housing is vibrated by the vibration device so that the vibration is propagated to the filter element fixed therein, the cause of wear is caused. Even if a filter element is vibrated without forming a sliding part or an ultrasonic vibrator, and a solid content having thixotropy accumulates on the filtration surface of the filter element to form a cake, it is always redispersed. In addition, even for volume filter type thick filter elements, it was found that the filtrate inside the element maintained fluidity by vibration, so that stable filtration could be performed for a long time without clogging. . In addition, since the structure is simple, cleaning at the time of lot switching becomes easy. Furthermore, in order to effectively and stably vibrate the hermetic filter housing, the hermetic filter housing is not simply placed, but is attached to the fixed base in a state where it can be vibrated by a support mechanism. The present inventors have found that it is necessary to make at least a part of piping (pipe) connected to the hermetic filter housing flexible, and have completed the present invention.
That is, the present invention fixes the filter element in the hermetic filter housing, divides the inside of the hermetic filter housing into two chambers, the treated slurry supply port in one chamber, and the treated chamber in the other chamber. In the filtration device provided with the slurry discharge port, the hermetic filter housing has a vibration device attached to an outer wall thereof, and is attached to a fixed base in a state that can be vibrated by a support mechanism. The filtration device is characterized in that a flexible pipe is connected to the treated slurry discharge port to supply the slurry to be treated and discharge the treated slurry.

  According to the filtration device of the present invention, in the filtration of slurry in which the concentrate exhibits thixotropy, the hermetic filter housing can be vibrated, and the vibration can be efficiently propagated to the filter element fixed therein. Thus, even if the slurry is concentrated on the surface of the filter element and the solid content having thixotropy is deposited to form a cake, the cake can be continuously fluidized and the filtration can be continued.

  Therefore, filtration can be performed stably for a long time while preventing clogging due to the solid content. Further, since there is no sliding portion inside and outside the filtration device, contamination from the sliding portion can be surely prevented, and a high-quality treated slurry can be obtained.

  As described above, in order to vibrate the filter element, the technical idea of vibrating the entire hermetic filter housing was proposed for the first time by the present invention, which enables continuous filtration of slurry exhibiting thixotropy by concentration. It can be said that high quality was achieved at the same time.

  Although the slurry used as the object of the filtration apparatus of this invention is not restrict | limited in particular, A viscosity is 5 centipoise or more and 5000 centipoise or less. Preferably, the slurry is 3000 centipoise or less. In particular, the slurry in which the effect of the filtration device of the present invention is remarkably exhibited is for a use in which the concentrate exhibits thixotropy and dislikes that impurities are mixed from the device into the treated slurry. It is suitable for obtaining a high quality slurry.

  Specifically, it is an aluminum nitride slurry used when producing a green body in the production of an aluminum nitride sintered body. When impurities such as metal fine powder are mixed into the aluminum nitride slurry from the filtration device, this is not only defective in the appearance of the aluminum nitride sintered body obtained by molding it into a green body, degreasing and firing, There also arises a problem that performance, for example, thermal conductivity and insulation are lowered.

  Other suitable slurry to be treated includes a slurry containing various ceramic powders such as a slurry containing alumina, silica, titania, zirconia, silicon nitride, silicon carbide and the like. Further, it can be used for recovering precious metals such as platinum, gold, palladium and rhodium, and rare metals such as strontium, tungsten, bismuth, neodymium and samarium. In such filtration, when impurities such as metal fine powder are mixed from the filtration device, in addition to deterioration in quality due to change in sinterability, electrical physical properties such as resistance value, dielectric constant, insulation due to metal mixed as foreign matter, A fatal problem of quality deterioration such as appearance occurs.

  Hereinafter, although the filtration apparatus of this invention is demonstrated in detail, referring an accompanying drawing, this invention is not limited to these accompanying drawings.

  FIG. 1 is a schematic view showing a typical embodiment of the filtration device of the present invention. FIG. 2 is a cross-sectional view showing an aspect of the internal state of the hermetic filter housing shown in FIG.

  As shown in FIG. 1 and FIG. 2, the filtration device of the present invention fixes the filter element 11 in the hermetic filter housing 1 and divides the hermetic filter housing into two chambers. In the filtration apparatus provided with the treated slurry supply port 3 and the treated slurry discharge port 4 in the other chamber, the hermetic filter housing 1 is provided with a vibration device 2 on its outer wall and can be vibrated by a support mechanism. In addition, a flexible pipe 3a, 4a is connected to the treated slurry supply port 3 and the treated slurry discharge port 4 to supply the treated slurry and discharge the treated slurry. It is the filtration apparatus characterized by performing.

  In the filtration device of the present invention, the hermetic filter housing 1 may be any one as long as it has a sealing property such that slurry does not leak to the outside due to vibration by the vibration device 2, and the shape thereof is also shown in the figure (circle). The shape is not limited to a cylindrical shape, and may be a spherical shape or a polygonal shape. Moreover, as a material of the hermetic filter housing, generally used materials such as stainless steel and iron can be preferably used. Materials that are coated with organic materials such as glass lining and fluororesin on highly corrosive slurries can also be used suitably, and materials that are coated with various ceramics are used to further improve wear resistance. You can also

  Moreover, the to-be-processed slurry supply port 3 and the processed slurry discharge port 4 provided in the said airtight filter housing 1 can be provided in arbitrary positions, as long as filtration is possible.

  Further, a known filter element 11 that divides the inside of the hermetic filter housing 1 into two is used without any particular limitation. Examples of typical filter element materials include stainless steel, paper, polyethylene, polypropylene, nylon, viscose rayon, ceramics, etc., which are knitted into a mesh shape, or surface filtered such as those formed into a membrane filter. Commonly available filter elements such as type, volume-filtered types such as those formed into a pincushion shape, wound into a non-woven fabric, or processed into a sintered metal can be used. An appropriate one may be selected in consideration of the nature of the foreign matter.

  Also, the method is not particularly limited, such as a volume filtration type, for example, a cylindrical type as shown in FIG. 2 or a plane type, but the airtightness of the divided chamber, ease of maintenance, and strength are taken into consideration. For example, the volume filtration type is preferable. Such a volume filtration type filter element can remove gel-like foreign matters, and is particularly convenient for removal of undissolved binders and coarse ceramic fine particles in a ceramic forming step, for example.

  Further, the opening of the filter element may be appropriately selected so that the target fine particles in the slurry can easily pass through and foreign substances can be filtered. For example, in the filtration of a slurry containing ceramic fine particles such as the aluminum nitride slurry, the opening may be adjusted so that particles of about 40 microns or more are generally removed as coarse particles.

  In addition, since the filtration device in the present invention has no clogging and good filtration efficiency, it can be finer than conventional filter elements, so that a higher quality slurry can be collected or filtered in a shorter time. It can be processed.

  The filter element 11 is required to be fixed to the hermetic filter housing 1 in order to reliably propagate the vibration applied to the hermetic filter housing 1 to the filter element. Further, in this case, it is preferable that the filter element 11 is fixed to the hermetic filter housing so as to vibrate together with the hermetic filter housing in order to propagate the vibration from the fixing portion to the entire filtration surface. For example, the filter element 11 is reliably integrated by a hermetic filter housing and a rigid fixing member.

  In addition, the filter element material itself has rigidity, specifically, the volume filtration type filter element is suitable. Of course, even a surface filtration type material can be used in a state in which bending is eliminated by applying tension, or it can be used as a volume filtration type filter element by being supported by a rigid formwork.

  In the filtration device of the present invention, a known vibration device is used as the vibration device 2 without any particular limitation. For example, a reciprocating motion type, a rotational motion type, etc. are mentioned.

  The vibration device 2 is directly attached to the outer wall of the hermetic filter housing so as to vibrate the entire hermetic filter housing 1. For the attachment, for example, a general attachment method such as attachment by welding as well as attachment by a fixture is appropriately adopted. Further, the attachment position is preferably attached to a position that gives vibration to the position of the center of gravity when the slurry is full in the sealed filter housing. Although not shown in the figure, a balance weight may be attached if necessary.

  In addition, when an organic solvent is included as a component of the slurry, it is a dangerous substance, so it is preferable in terms of safety to use an air-driven vibrating body rather than an electric type.

  The vibration strength by the vibration device may be selected in consideration of the properties of the slurry to be filtered and the filtration resistance of the filter medium, giving the optimum vibration strength. In general, it is preferable to select a frequency of 100 to 3000 times / minute and an amplitude of 0.5 to 5 mm.

  The principle of filtration in the filtration device of the present invention is that the slurry showing thixotropy due to the vibration force behaves as a fluid, so that effective filtration is possible by stopping the growth of the filter cake on the filter medium surface. Presumed. In addition, when a cylindrical element is used as the filter element, it is presumed that the effect of cleaning the surface of the filter element due to the swirling motion of the filtered stock solution in the filter housing due to vibration also works.

  In the filtration device of the present invention, it is necessary for the support mechanism of the hermetic filter housing 1 to attach the hermetic filter housing to the fixed base in a state in which the hermetic filter housing can vibrate in order to propagate the vibration by the vibration device 2 to the filter element 11. is there.

  That is, the conventional filtration device is of a type that is directly fixed to a fixed base (including the ground). In this type, the hermetic filter housing cannot be vibrated by the vibration of the vibration device 2, and the filter element 11 Cannot vibrate efficiently.

  The support mechanism is not particularly limited as long as it is a structure in which the hermetic filter housing 1 is not directly fixed to the fixed base 5, that is, a structure that is supported in a state where vibration can be performed by the vibration device. As an example of a typical embodiment, as shown in FIG. 1, a structure in which a sealed housing 1 is suspended from a fixed base 5, FIGS. 2 and 3 (showing a support mechanism for a sealed filter housing, and flexible pipes are omitted. As shown in FIG. 5, there is a structure in which the hermetic filter housing 1 is sandwiched between the fixed base 5 via an elastic body.

  Referring to FIG. 1 in more detail, the hermetic filter housing 1 is provided with ribs 6 on the side walls thereof, and by connecting the ribs 6 and the fixing base with support rods via spring cylinders 7 in the middle. It is suspended from the fixed base 5. In FIG. 3, the hermetic filter housing 1 is sandwiched by the fixing base 5 via the elastic body 8 from the lateral direction (FIG. 3) and from the vertical direction (FIG. 4). Here, as an elastic body, rubber | gum, sponge, etc. are common. 3 and 4, the elastic body 8 is pressed against the hermetic filter housing by the pressurizing tool 9.

  The results of conducting a filtration experiment using this vibration filter are shown below. The viscosity was measured using a DVL-B type rotational viscometer manufactured by Tokyo Keiki. Depending on the viscosity of the slurry, no more than 100 centipoise slurries. No. 2 rotor for slurry in the range of 100 to 10,000 centipoise. Using 3 rotors, rotating at 12 revolutions per minute at a temperature of 20 ± 1 ° C., reading the indicated value after 30 seconds, and determining the viscosity of the slurry.

Example 1
100 parts of aluminum nitride powder made by alumina reduction nitriding method, 5 parts of yttria as sintering aid, 5 parts of polymethacrylic acid etc. as binder, dispersant etc., toluene as solvent and 120 parts of ethanol meter in nylon About 200 kg of aluminum nitride slurry was obtained by mixing overnight in a ball mill made of nylon using steel balls coated with nylon. The slurry had a viscosity of about 40 centipoise.

This slurry refiner incorporates a pincushion type filter element made of viscose rayon with an outer diameter of 60 mm, a length of 250 mm, and a filtration accuracy of 50 microns. It is an air-driven pump (maximum discharge pressure 5 kg / cm ² G) And purified slurry was obtained. The time required for purification is about 7 minutes, and the differential pressure (the value obtained by subtracting the static pressure on the secondary side from the static pressure on the primary side of the slurry purification apparatus) is stable at about 2 Kg / cm ² G until the end of purification. Was.

The slurry refiner was equipped with an Exen pneumatic ball vibrator as a vibration source and operated at an air pressure of about 2 Kg / cm ² G and a single amplitude of about 1.5 mm. In addition, aluminum nitride granules are made from the refined slurry by spray granulation, and then an aluminum nitride molded body is made by dry press, then degreased and sintered, and the surface of the sintered body is polished and fully experienced. When the number of small holes on the surface and the number of defects of foreign matters were counted visually by an inspector loaded with the above, it was 1 × 10 ⁻⁴ pieces / cm ² or less.

  Further, the same slurry was further produced several times, and filtration was repeated under the same conditions using this slurry purification apparatus. However, the filter element was not blocked and could not be purified. Furthermore, the result of visual inspection of the sintered body surface was almost the same.

Comparative Example 1
When filtration was performed under the same conditions as in Example 1 except that the vibrator of the slurry purification apparatus was not operated in Example 1, the filter was blocked immediately after the start of filtration, and filtration was impossible at all.

Comparative Example 2
The slurry having the same composition as in Example 1 was filtered through a cartridge filter having a stainless mesh filter element having an outer diameter of 60 mm, a length of 500 mm, and an aperture of 40 microns. The time required for filtration was about 7 minutes. The filtration pressure (differential pressure) was 1 kg / cm ² G immediately after the start of filtration, but increased to 3 kg / cm ² G at the end of filtration.

A sintered body was prepared in the same manner as in Example 1, and the number of defects in the surface small holes and foreign matters was counted visually. As a result, the number of defects was 2 × 10 −4 pieces / cm ² . In addition, as a result of observing the defects in more detail, a cavity of a diameter of 10 microns or more and an estimated number of tens to 100 microns or more was observed in the sintered body. It seemed to be the cause. In addition, a defect caused by contamination of metal foreign matter was also found by an X-ray fluorescence analyzer.

  In addition, when the same slurry was produced several times and a filtration experiment with the same cartridge filter was conducted, the filter was often clogged and could not be filtered.

Example 2
A slurry was prepared by adding 250 ppm and 350 ppm on a 45-micron sieve as a foreign substance to a slurry having the same composition as in Example 1, and filtered under the same operating conditions using the same slurry filtration apparatus as in Example 1. Pressure) increased to 3 Kg / cm ² G or more and filtration time was 12 to 15 minutes, but filtration was possible. Moreover, when the sintered compact was created similarly to Example 1 and the number of defects of the surface small hole and a foreign material was counted visually, the number of defects was 1 * 10 < ^-4 > piece / cm < ² > or less similarly to Example 1. there were. None of the defects were presumed to be due to a 45 micron sieve (coarse particles) or metal foreign matter.

Example 3
100 parts of aluminum nitride powder made by alumina reduction nitriding method, 5 parts of yttria as sintering aid, 13 parts of polyvinyl butyral, dibutyl butyral etc. as binder, dispersant etc., toluene as solvent and 120 parts of ethanol In a nylon ball mill, the steel balls coated with nylon were mixed for about overnight to obtain about 200 kg of an aluminum nitride slurry for forming a sheet. This slurry was operated in the same manner as in Example 1 by using the same slurry purification apparatus incorporating a pincushion type filter element made of viscose rayon having an outer diameter of 60 mm, a length of 250 mm and a filtration accuracy of 50 microns as in Example 1. Filtered under conditions. The slurry had a viscosity of about 300 centipoise and filtration took about 12 minutes. Further, the filtration pressure (differential pressure) tended to increase from the start to the end of filtration, but was stable at about 1 Kg / cm ² G or less. Sheet molding was performed to prepare a sintered body having a size of 2 inches × 2 inches, and visual inspection for defects was performed by a skilled inspector. As a result, the defect rate was 0.3% or less.

  Further, the same slurry was produced several times, and the filtration experiment was repeated using the same slurry purification apparatus under the same operating conditions as in Example 1. As a result, the viscosity of the slurry showed 200 to 500 centipoise. Further, the filter element was not blocked and could not be purified. Furthermore, the defect rate of the sintered body was 0.3% or less.

Comparative Example 4
A slurry having the same composition as in Example 3 was filtered at a jet pressure of 85 kg / cm 2 G using a jet filter M-15 / 5 type manufactured by Fuji Filter Industry. As a result of several runs, the viscosity of this slurry varied from 250 to 500 centipoise. The time required for filtration was 15 to 20 minutes. When a sintered body was prepared and visually inspected in the same manner as in Example 3, the defect rate based on defects varied from 0.3% to 2%. Moreover, as a result of observing the defective portion with a scanning electron microscope and a fluorescent X-ray analyzer, it was found that the defect was mainly caused by coarse particles, lint and metal powder in the filtration slurry.

Example 4
A slurry having the same composition as that of Example 3 was prepared, and this was carried out using a slurry purification apparatus incorporating a bobbin rayon pincushion type filter element having an outer diameter of 60 mm, a length of 250 mm, and a filtration accuracy of 25 microns. Filtration under the same operating conditions as in Example 1. The slurry had a viscosity of about 280 centipoise and filtration took about 18 minutes. Further, the filtration pressure (differential pressure) was stable at about 3 Kg / cm 2 G although there was an upward trend from the start to the end of filtration. Sheet molding was performed to prepare a sintered body having a size of 2 inches × 2 inches, and visual inspection for defects was performed. As a result, the defect rate was 0.2% or less.

Comparative Example 5
A slurry having the same composition as in Example 3 was filtered through a cartridge filter containing a filter element of stainless mesh having an outer diameter of 60 mm, a length of 500 mm, and an opening of 20 microns. The time required for filtration was about 15 minutes. Also, filter pressure is increased from 1Kg / cm ² G until 5Kg / cm ² G close. When a sintered body was prepared and visually inspected in the same manner as in Example 4, the defect rate based on defects was 1.5%. The defects were presumed to be mainly caused by metal foreign matter, coarse particles of aluminum nitride, and lint as in Comparative Example 4.

  In addition, when the same slurry was produced several times and a filtration experiment with the same cartridge filter was conducted, the filter was often clogged and could not be filtered.

The perspective view which shows the typical aspect of the filtration apparatus of this invention Sectional drawing which shows the one aspect | mode of the internal structure of the airtight filter housing in the filtration apparatus of this invention Schematic which shows the other aspect of the holding structure of the airtight filter housing in the filtration apparatus of this invention. Schematic which shows the other aspect of the holding structure of the airtight filter housing in the filtration apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing filter housing 2 Vibrating device 3 To-be-processed slurry supply port 3a Flexible pipe 4 Treated slurry discharge port 4a Flexible pipe 5 Fixing stand 6 Rib 7 Spring cylinder 8 Elastic body 9 Pressurizing tool 10 Filter element

Claims (5)

The filter element is fixed in the hermetic filter housing, and the inner part of the hermetic filter housing is divided into two chambers. A treated slurry supply port is provided in one chamber, and a treated slurry discharge port is provided in the other chamber. In the filtration device, the hermetic filter housing has a vibration device attached to an outer wall thereof, and is attached to a fixed base in a state that can be vibrated by a support mechanism, and is further connected to the treated slurry supply port and the treated slurry discharge port. Is a filtration device characterized in that a flexible pipe is connected to supply the slurry to be treated and discharge the treated slurry. The filtration device according to claim 1, wherein the filter element is a volume filtration type filter element. The filtration device according to claim 1, wherein the support mechanism has a structure in which the hermetic housing is suspended from a fixed base. The filtration device according to claim 1, wherein the support mechanism has a structure in which the hermetic housing is clamped or held by an elastic body on a fixed base. The filtration device according to any one of claims 1 to 3, wherein the untreated slurry is a slurry that exhibits thixotropy by concentration.

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