JP2010132530A - High-strength zeolite bead molding and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that shaped beads formed from zeolite and a clay binder by tumbling granulation are problematic in that the strength and abrasion resistance are poor. <P>SOLUTION: Shaped zeolite beads with an average diameter of 1.0-3.0 mm having compressive strength of ≥35 N (particularly ≥70 N) when hydrated and an abrasion resistance factor of ≤1.5% are obtained by subjecting a composition of at least 35 pts.wt. of water per 100 pts.wt. of zeolite and the clay binder combined by tumbling granulation to carry out molding in a bead shape and then adding ≤4 pts.wt. of clay binder of the molding (excluding the water content), subjecting the product to tumbling grading, drying, and firing. Preferably the zeolite crystals used are ≤5 μm, 10-50 pts.wt. of clay binder are used, and the same type of clay binder is used for molding and grading. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a zeolite bead molded body having high strength and particularly high wear resistance, and a method for producing the same. For example, a zeolite bead molded body used for a Freon desiccant for an air conditioner of an automobile is required to have particularly high strength and wear resistance so as not to be pulverized by vibration of an engine drive.

  Zeolite bead moldings are widely used as desiccants, but recently, the demand for desiccants for automobile air conditioners is increasing. Since air conditioners for automobiles are exposed to vibration during use, if the strength and wear resistance are low, powdering may cause clogging, and a desiccant with high strength and high wear resistance is required.

  As a method of obtaining a desiccant having high strength and high abrasion resistance, for example, a method using an additive such as condensed phosphate as a binder, a method using a special needle-like crystal binder as a binder (Patent Document 2), A method of treating with an alkaline compound (Patent Document 3, Patent Document 4) and the like have been proposed. However, all of these methods require special raw materials and special processing steps, and have been the cause of increased costs for desiccants.

  In any of the methods, it has been pointed out that the obtained molded body particles are sized to smooth the surface of the molded body and increase the sphericity, but a sufficient effect has not been obtained.

  In addition, there is also known a method (Patent Document 5) in which a high-strength pellet molded body is rounded by rolling sizing. In such a method, particles having high strength can be obtained, but a molded product having a high sphericity cannot be obtained.

JP 2001-261330 A JP-A-11-314913 Japanese Patent Laid-Open No. 4-198012 JP-A-6-327968 JP-A-10-87322

  The object of the present invention is to increase the strength (hydration pressure resistance) and wear resistance of beads, especially 3A type zeolite (K ion exchange A type zeolite) and clay binder, without using special raw materials and processes. It provides a way to improve.

  As a result of intensive studies on the improvement of the hydration pressure strength and wear resistance of the zeolite bead molded article, the present inventors have added a specific range of clay binder during rolling sizing after granulation, It has been found that the hydration pressure strength and wear resistance of the molded product are remarkably improved, and the present invention has been completed.

  Hereafter, the manufacturing method of the zeolite bead molded object of this invention is demonstrated.

  The method for producing a zeolite bead molded body according to the present invention comprises molding a composition having a water content of 35 parts by weight or more into a bead shape by rolling granulation with respect to 100 parts by weight of the zeolite and the clay binder, and then molding the solid content weight. After adding 4 parts by weight or less of a clay binder (excluding moisture) and rolling and sizing, it is dried and fired.

  In the method of the present invention, if the water content with respect to the zeolite and clay binder at the time of molding is too small, a bead molded body cannot be obtained, and if it is too much, the molded bodies adhere to each other and the molded body grows abnormally. The amount of water relative to 100 parts by weight of the zeolite and the clay binder is adjusted depending on the particle size and surface area of the clay binder used, but is preferably at least 35 parts by weight, particularly 35 to 60 parts by weight.

  In the present invention, the composition having the above water content is molded into beads, and then 4 parts by weight or less of a clay binder is added to 100 parts by weight of the solid content of the molded body (excluding water) to perform rolling sizing. This improves the strength and wear resistance.

  Molding and sizing in the present invention are not particularly limited as long as a bead-shaped molded body can be molded, and any of a general rolling granulator, drum granulator, and rotary cylindrical granulator can be used. it can.

  It is known that a zeolite bead molded body containing a clay binder is smoothened by adjusting the particle size to improve the wear resistance to some extent. However, the conventional sizing is an effect of removing foreign substances adhering to the surface of the molded body and smoothing the surface, and the effect is only limited.

  In the present invention, by adding a clay binder in a specific range at the time of rolling sizing, not only cleaning the surface of the molded body at the time of rolling sizing, but also a defect replenishment and a stronger protective layer is formed, Despite the addition of a small amount of binder, the strength is remarkably improved.

  In the present invention, the clay binder added at the time of rolling sizing is 4 parts by weight or less with respect to 100 parts by weight of the solid weight of the molded body (the solid weight of zeolite and clay binder at the time of rolling granulation, excluding moisture). In particular, a range of 0.01 to 3 parts by weight, and further 0.1 to 3 parts by weight is preferable.

  When the amount of the clay binder added during rolling sizing exceeds 4 parts by weight, the pressure resistance of the molded body is improved, but there is a problem that the wear resistance is lowered.

  The amount of water at the time of rolling sizing is 35 parts by weight or more, particularly 35 to 35 parts by weight with respect to 100 parts by weight of the solid weight of the compact (excluding moisture. Zeolite and clay binder. Including clay binder added at the time of rolling sizing). A range of 45 parts by weight is preferred.

  When adding a clay binder during rolling sizing, it is preferable to adjust the amount of water by adding water together with the clay binder. The water added together with the clay binder at the time of rolling sizing has an effect of making the added clay binder easily form a protective layer on the surface of the molded body.

  At the time of rolling sizing, if the molded body is dried due to a temperature rise due to friction between particles, the effect of the present invention cannot be sufficiently obtained even if rolling sizing is performed by adding a clay binder.

  As the clay binder used in the present invention, it is preferable to use the same kind of clay binder used for molding and clay binder added at the time of granulation. By using the same clay binder, a molded product having particularly high wear resistance can be obtained by adding a small amount of clay binder.

  The clay binder for the zeolite used in the present invention is not particularly limited. The kaolin clay which is a plate-shaped crystal | crystallization is especially preferable. Further, the addition amount of the clay binder to the zeolite is preferably 10 parts by weight or more and 50 parts by weight or less, particularly more than 40 parts by weight and 50 parts by weight or less with respect to 100 parts by weight of the zeolite (excluding moisture) in the finally obtained molded body. . When the amount of the binder is too small, the strength is insufficient, and when it is too large, the performance as a desiccant per unit weight is lowered.

  The clay binder added at the time of rolling sizing is 4% by weight or less of the weight of the molded body at the time of granulation, and the clay binder is preferably 40 parts by weight or more and 44 parts by weight or less with respect to zeolite.

  The zeolite used in the present invention is not particularly limited, but when used as a desiccant for an automotive air conditioner, it is preferably a K ion exchange type A zeolite that does not adsorb chlorofluorocarbon and selectively adsorbs only moisture.

  3A-type zeolite powder is obtained by a known method, that is, sodium A-type zeolite powder synthesized from sodium aluminate and sodium silicate is exchanged with potassium ions in potassium chloride aqueous solution, and 35% or more of sodium ions in the zeolite are exchanged with potassium ions. The 3A-type zeolite powder having an effective pore diameter of 3 angstroms can be obtained.

  The particle size of the zelite crystal used in the present invention is preferably 5 μm or less, particularly preferably 3 to 4 μm. When the particle size of the zeolite crystal is too large, the wear resistance tends to be lowered.

  The sizing time in the present invention is not limited, but since a sufficient effect cannot be obtained in a short time, it is preferable to treat at least 10 minutes or more, particularly 60 minutes or more.

  In the present invention, as long as the performance of the zeolite desiccant is not adversely affected, in addition to the clay binder, a dispersant and a molding aid (an auxiliary agent such as CMC) may be included.

  The conditions for drying and calcination in the production method of the present invention are not particularly limited, but the zeolite is hydrothermally deteriorated when calcinated in a dry state with a high water content or calcinated at a high temperature. Performance decreases. The moisture content at the time of drying is 10 to 32% in terms of ig-loss, particularly 10 to 25%, and the firing temperature is 600 to 800 ° C, particularly 600 to 700 ° C, and the method of firing for several hours to 10 hours can be exemplified. .

  As drying and activation methods, known methods can be used. For example, a hot air dryer, an electric muffle furnace, a tubular furnace, a rotary furnace, etc. may be used.

  In the method of the present invention, the zeolite crystal diameter is 5 μm or less, the clay binder is 10 parts by weight or more and 50 parts by weight or less, particularly more than 40 parts by weight and 50 parts by weight or less, the hydration pressure strength 35N (= 3.57 kgf) or more, It is possible to obtain a zeolite bead molded body having a wear resistance of 1.5% or less and an average diameter of 1.0 to 3.0 mm in a range of 70 N (= 7.14 kgf) or more.

  The zeolite crystal diameter is preferably 5 μm or less, particularly 3 to 5 μm. The zeolite crystal diameter can be confirmed by SEM observation. When the zeolite crystal diameter is larger than 5 μm, the wear resistance tends to be lowered.

  The clay binder in the finally obtained zeolite bead molded body is 10 parts by weight or more and 50 parts by weight or less, especially 40 parts by weight or more and 50 parts by weight or less with respect to 100 parts by weight of zeolite (excluding moisture). Is preferred. The clay binder used is a plate-like crystal, preferably having a crystal size comparable to or smaller than that of the zeolite particles. If the binder is less than 10 parts by weight, the strength and wear resistance are insufficient, and if it exceeds 50 parts by weight, the performance as a desiccant (adsorbent) decreases.

  The particle size of the zeolite bead molded body is in the range of 1.0 to 3.0 mm, and particularly preferably in the range of 1.4 to 2.5 mm.

  Since the zeolite bead molded body obtained by the method of the present invention is not added (impregnated) with a conventional vitrifying agent such as sodium silicate, it has excellent toughness and does not block the pores of the molded body due to the vitrifying agent. Therefore, the adsorption performance is excellent. Whether or not it is a molded body to which a vitrifying agent such as sodium silicate is added can be confirmed by confirming the structure with an electron microscope.

  The zeolite bead molded body of the present invention has a hydration pressure strength of 35 N (= 3.57 kgf) or more, particularly 70 N (= 7.14 kgf) or more, and an abrasion resistance of 1.5% or less. The wear resistance is particularly preferably 1% or less. The pressure strength and wear resistance of the present invention are both performances in a hydrated state (phase humidity 80%). In a dry (non-hydrated) state, even higher pressure strength and wear resistance are exhibited, but in practice, strength and wear are problematic in a state of advanced hydration. In the present invention, it is significant that the compressive strength and the wear resistance are high in a hydrated state.

  The hydration pressure strength in the present invention is based on a crushing strength test method for a granulated product described in a granulated product-strength test method described in JIS-Z-8841 for a sample hydrated at a relative humidity of 80%. It is a measured value, and the abrasion resistance is measured by a weight reduction ratio by shaking for 1 hour with a general-purpose paint conditioner using 100 ml of a hydrated sample and 55 ml of an organic solvent (trichloroethylene) for testing. .

  In the production method of the present invention, a mixture of 35 parts by weight or more of moisture is formed into beads by rolling granulation with respect to 100 parts by weight of zeolite and clay binder, and then 4 parts by weight or less based on the weight of the molded body. A zeolite desiccant with high strength and high wear resistance can be produced by adding clay clay and rolling and sizing, followed by drying and firing. The zeolite bead molded body obtained by the method of the present invention is excellent in strength and wear resistance.

It is a figure which shows the surface SEM image after the sizing of the molded object of Example 1. FIG. It is a figure which shows the surface SEM image after the sizing of the molded object of Example 2. FIG. It is a figure which shows the surface SEM image of the comparative example 1 (unshaped granulated body). It is a figure which shows the surface SEM image after the sizing of the molded object of the comparative example 3. FIG.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

(Measurement method of strength (hydration pressure strength))
The zeolite bead molded body hydrated at 80% relative humidity is measured based on the granulated product crushing strength test method described in the granulated product-strength test method described in JIS-Z-8841. The maximum load that the zeolite bead compact can withstand when a compression load is applied by pressing the pressure plate at a constant speed in the diameter direction of the granular material, which is a test piece, in a normal temperature and normal pressure atmosphere using a hardness meter. Measure.

  In the present invention, a fired zeolite bead molded body having a diameter of 1.4 mm to 2.4 mm is used to measure the pressure strength in the diametrical direction of a cylindrical column having a diameter of 5 mm, using a Kiya digital hardness meter (KHT-20 type). Measured with a pressure plate. A pressure plate made of stainless steel was used, and 25 pressure-resistant strengths were measured.

(Measurement method of wear rate)
Measure the weight loss after loading 100 ml of zeolite bead hydrated at 80% relative humidity and 55 ml of trichloroethylene into a screw mouth bottle (130 ml) and shaking with a paint shaker (Toyo Seiki Seisakusho) for 1 hour. did. After shaking, wear particles are separated with a 1 mm sieve and the change in weight is measured.

Example 1
40 parts by weight of kaolin clay is mixed with 100 parts by weight of zeolite (K ion exchange A-type zeolite), and then 50 parts by weight of water is mixed with 100 parts by weight of zeolite and kaolin clay. Molded and sieved to obtain a 1.7 mmφ preform. The water content of the preform after molding (calculated as ig-loss at 900 ° C. firing) was 36 parts by weight. 3 parts by weight of kaolin clay having a different production area from that used for molding to the molded body is added to 100 parts by weight of the solid content of the preform, and the moisture content of the molded body is adjusted to 37 parts by weight with a sprayer. Rolled and sized for 70 minutes. Then, it dried and baked at 680 degreeC for 5 hours.

  The characteristics of the obtained bead molded body are shown in Table 1, and the cross section (surface) of the molded body after sizing is shown in FIG. Formation of a protective layer was confirmed on the surface of the molded body.

Example 2
The same treatment as in Example 1 was performed except that kaolin clay of the same production area was used for molding and rolling sizing, and the binder added during rolling sizing was 0.1 parts by weight.

Table 1 shows the characteristics of the obtained bead molded body, and FIG. 2 shows a cross section (surface) of the molded body after sizing.
Formation of a protective layer was confirmed on the surface of the molded body.

Example 3
43 parts by weight of kaolin clay is mixed with 100 parts by weight of zeolite (K ion exchange A-type zeolite), and then 55 parts by weight of water is mixed with 100 parts by weight of zeolite and kaolin clay. Molded and sieved to obtain a 1.7 mmφ preform. The water content of the pre-molded body after molding (ig-loss conversion at 900 ° C. firing) was 38 parts by weight. 3 parts by weight of kaolin clay from the same production area as that used for molding is added to the molded body in an amount of 100 parts by weight of the solid content of the preform, and the moisture content of the molded body is adjusted to 39 parts by weight with a sprayer. Rolled and sized for a minute. Then, it dried and baked at 680 degreeC for 5 hours.

  The properties of the obtained bead molded body are shown in Table 1.

Comparative Example 1
The same process as in Example 1 was performed without rolling and sizing the preformed body of Example 1.

  The characteristics of the obtained bead molded body are shown in Table 1, and the cross section (surface) of the molded body is shown in FIG. It was a molded product with many irregularities on the surface and insufficient hydration pressure strength and abrasion resistance.

Comparative Example 2
The same treatment as in Example 1 was performed except that 7 parts by weight of the clay binder added at the time of rolling sizing was used.

  The properties of the obtained bead molded body are shown in Table 1. Since the clay binder added during sizing was large, the strength was improved, but the molded product had a large wear rate. The formation of a protective layer formed during sizing was observed on the surface of the molded body, but it was a thick layer of a binder alone, and the difference in structure from the inside of the molded body was remarkable.

Comparative Example 3
The same treatment as in Example 1 was performed except that 5 parts by weight of the clay binder added at the time of rolling sizing was used.

  Table 1 shows the characteristics of the obtained bead molded body, and FIG. 4 shows the cross section (surface) of the molded body. Although the wear rate was improved as compared with Comparative Example 2, it was not sufficient. The surface of the molded body after rolling sizing is shown in FIG.

  The present invention relates to a zeolite bead molded body having high strength and particularly high wear resistance, and a method for producing the same. For example, it can be used as a chlorofluorocarbon desiccant for automobile air conditioners that require high strength and wear resistance.

Claims (10)

After 100 parts by weight of zeolite and clay binder are molded into beads by composition rolling granulation with a water content of 35 parts by weight or more, 4 parts by weight or less with respect to the solid weight of the molded body (excluding water) A method for producing a zeolite bead molded body in which a clay binder is added, rolling and sized, dried and fired. The manufacturing method of Claim 1 which makes the water | moisture content in the molded object at the time of rolling sizing 35 weight part or more. The production method according to claim 1 or 2, wherein the clay binder is a plate-like crystal. The production method according to any one of claims 1 to 3, wherein the zeolite is K ion exchange type A zeolite. The production method according to claim 4, wherein the zeolite crystal diameter is 5 μm or less. The manufacturing method according to any one of claims 1 to 5, wherein the total amount of the clay binder with respect to the zeolite in the zeolite bead molded body is 10 parts by weight or more and 50 parts by weight or less. The manufacturing method according to claim 6, wherein the total amount of the clay binder with respect to the zeolite is more than 40 parts by weight and 50 parts by weight or less. Zeolite beads having a zeolite crystal of 5 μm or less, a clay binder of 10 to 50 parts by weight, a hydration pressure strength of 35 N or more, an abrasion resistance of 1.5% or less, and a bead diameter of 1.0 to 3.0 mm Molded body. The zeolite bead molding according to claim 8, wherein the total amount of the clay binder is more than 40 parts by weight and 50 parts by weight or less. The zeolite bead molded product according to claim 8 or 9, wherein the hydration pressure strength is 70 N or more.

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