A casting binder and its preparation method

Abstract

This invention belongs to the field of adhesive technology, and relates to a casting adhesive and its preparation method. The casting adhesive of this invention uses crushed ceramic tubes as raw material, reusing used crushed ceramic tubes, protecting the environment and reducing production costs. The mesh size of the ceramic tubes is slightly smaller than that of the molding sand. Adding an appropriate amount of crushed ceramic tube material makes the connection between two sand molds tighter, compressing the sand molds and squeezing the ceramic tube particles into the middle gaps. Due to the rough surface, it has better bonding strength. Replacing multiple small particles with larger overall particles also increases strength and permeability, shortens curing time, and further improves bonding strength and high-temperature stability through the mixed use of water glass and resin. The compressive strength can be increased from about 1.9 MPa to about 3.9 MPa.

Description

Technical Field

[0001] This invention belongs to the field of binder technology, and relates to a casting binder and its preparation method. Background Technology

[0002] Sand casting is a casting method that produces castings in sand molds. Steel, iron, and most non-ferrous alloy castings can be obtained using sand casting. Because the molding materials used in sand casting are inexpensive and readily available, and the mold making is simple, it can adapt to single-piece production, batch production, and mass production of castings. For a long time, it has been a basic process in casting production.

[0003] Large castings, due to their small batch size and large dimensions, can only be made by manual molding. During the molding process, sand molds often break due to mold design flaws, incomplete resin sand curing, or improper manual handling during demolding. Existing binders have low bonding strength, cannot meet the bonding requirements of large sand molds, and have poor high-temperature stability. There is an urgent need for a casting binder that can bond broken sand molds together, possesses sufficient strength, and has a fast drying speed. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the prior art by proposing a casting binder with short curing time, excellent physical properties, and low cost.

[0005] The objective of this invention can be achieved through the following technical solution: a casting binder comprising the following raw materials in parts by weight: 16-18 parts montmorillonite powder, 6-6.5 parts deionized water, 8-15 parts broken ceramic tube material, 3-5 parts furan resin, 23-25 ​​parts water glass, 18-23 parts refractory mortar, and 2-5 parts water.

[0006] This invention utilizes broken ceramic tube material and montmorillonite powder as fillers in the adhesive, with the broken ceramic tube material serving as the main filler. The gaps are filled with montmorillonite powder and refractory mortar. Furthermore, furan resin, water glass, and deionized water are used to synergistically promote bonding, greatly improving the bonding strength and high-temperature stability.

[0007] In the aforementioned casting binder, the montmorillonite powder has a particle size of 250-280 mesh. This invention utilizes the viscosity, thixotropy, and lubricity of montmorillonite powder mixed with deionized water. When the particle size is controlled to 250-280 mesh, it can be thoroughly mixed with deionized water, activating the free particles within the montmorillonite powder to form hydrogen ions and hydroxide ions, resulting in better wettability, facilitating full contact, and improving bonding strength.

[0008] In the aforementioned casting binder, the particle size of the crushed ceramic tubes is 50-70 mesh. This invention utilizes the crushed ceramic tubes to maximize the use of waste materials, thereby reducing costs by decreasing the amount of raw and auxiliary materials used. Furthermore, it increases the air permeability of the binder with almost no impact on strength and significantly shortens the curing time.

[0009] Preferably, the broken ceramic tube material includes at least one of the following: high-temperature resistant ceramic tube, medium-diameter tube, refractory pre-embedded straight gating system (as a gating system to transfer molten iron), right-angle bend (as a gating system to transfer molten iron and change the direction of molten iron flow), tee pipe, four-way pipe, five-way pipe, six-way pipe, seven-way pipe (as a gating system to transfer molten iron and distribute molten iron to multiple ingates), refractory brick, anti-impact sand ring, and anti-impact sand base (for molten iron to directly impact the platform and buffer the molten iron). The ceramic tubes used in this invention are either unusable due to damage or were discarded as waste after use.

[0010] Further preferred, the components of the crushed ceramic tube include at least one of bauxite, bentonite, calcined sapphire, and kyanite.

[0011] As a preferred option, the refractory mortar has a particle size of 180-220 mesh.

[0012] In one of the above-mentioned casting binders, the broken ceramic tube material is impregnated.

[0013] In one of the above-mentioned casting binders, the impregnation treatment specifically involves immersing the broken ceramic tube material in a mixture of water glass and water for impregnation.

[0014] In the aforementioned casting binder, the mass ratio of water glass to water is 1:

[0015] (4-4.5).

[0016] The present invention also provides a method for preparing a casting binder, the method comprising the following steps:

[0017] S1. First, mix 3-5 wt% montmorillonite powder with deionized water evenly and then put it into a mixer.

[0018] S2. Then mix the furan resin and water glass, heat and seal the mixture before putting it into a mixer;

[0019] S3. Add refractory mortar, remaining montmorillonite powder, water, and broken ceramic tubes into the mixer in sequence, and mix all raw materials evenly to obtain a binder.

[0020] This invention promotes the ionization of hydrogen ions and hydroxide ions by first stirring a small portion of montmorillonite powder with deionized water, thereby improving the wettability of the particle surface and enabling the binder to better bond with the particles, thus facilitating the improvement of particle surface adhesion strength.

[0021] In the above-mentioned method for preparing a casting binder, the heating and stirring temperature is 80-95℃, and the time is 2-5 minutes. Furan resin has good high-temperature stability and high strength, while water glass has a fast setting speed, lower high-temperature strength, and poor high-temperature stability. This invention improves the high-temperature resilience of the water glass binder by briefly heating and stirring in a closed manner to ensure thorough mixing of the two. During use, after the water glass binds the core together, the resin begins to solidify, increasing its strength.

[0022] Compared with the prior art, the present invention has the following beneficial effects: The casting binder of the present invention uses broken ceramic tubes, which reuses the broken ceramic tubes after use, protects the environment and reduces production costs; the mesh size of the ceramic tubes is slightly smaller than that of the molding sand, and adding an appropriate amount of broken ceramic tubes can make the connection between the two sand molds tighter, compress the sand molds, and squeeze the ceramic tube particles into the middle gap. Due to the rough surface, it has better bonding strength. Replacing multiple small particles with large particles as a whole also increases strength and air permeability, shortens curing time, and further improves bonding strength and high temperature stability by using a mixture of water glass and resin. The compressive strength can be increased from about 1.9 MPa to about 3.9 MPa. Detailed Implementation

[0023] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0024] Example 1:

[0025] S1. Prepare the raw materials according to the following mass proportions: 16.3 parts montmorillonite powder with a mesh size of 270, 6.48 parts deionized water, 10 parts ceramic tube crushed material with a mesh size of 60, 3.55 parts furan resin, 24.5 parts water glass, 21 parts refractory mortar with a mesh size of 200, and 3 parts water; wherein the ceramic tube crushed material needs to be put into a mixed liquid of water glass and water in a ratio of 5.5:24, stirred for 5 minutes, and then drained for later use.

[0026] S2. First, mix 0.65 parts of montmorillonite powder with deionized water evenly and then put it into the mixer;

[0027] S3. Then mix the furan resin and water glass, heat and stir at 85°C for 3 minutes, and then put it into a mixer.

[0028] S4. Finally, add the refractory mortar, remaining montmorillonite powder, water, and broken ceramic tubes into the mixer in sequence, and mix all the raw materials evenly to obtain the binder.

[0029] Example 2:

[0030] S1. Prepare the raw materials according to the following mass proportions: 16.0 parts montmorillonite powder with a mesh size of 270, 6.0 parts deionized water, 8 parts ceramic tube crushed material with a mesh size of 60, 3.0 parts furan resin, 23.0 parts water glass, 18 parts refractory mortar with a mesh size of 200, and 2 parts water.

[0031] S2. First, mix 0.48 parts of montmorillonite powder with deionized water evenly and then put it into the mixer;

[0032] S3. Then mix the furan resin and water glass, heat and stir at 80°C for 2 minutes, and then put it into the mixer.

[0033] S4. Finally, add the refractory mortar, remaining montmorillonite powder, water, and broken ceramic tubes into the mixer in sequence, and mix all the raw materials evenly to obtain the binder.

[0034] Example 3:

[0035] S1. Prepare the raw materials according to the following mass proportions: 18.0 parts montmorillonite powder with a mesh size of 270, 6.5 parts deionized water, 15 parts ceramic tube crushed material with a mesh size of 60, 5.0 parts furan resin, 25.0 parts water glass, 23 parts refractory mortar with a mesh size of 200, and 5 parts water.

[0036] S2. First, mix 0.9 parts of montmorillonite powder with deionized water evenly and then put it into the mixer;

[0037] S3. Then mix the furan resin and water glass, heat and stir at 95°C for 5 minutes, and then put it into the mixer.

[0038] S4. Finally, add the refractory mortar, remaining montmorillonite powder, water, and broken ceramic tubes into the mixer in sequence, and mix all the raw materials evenly to obtain the binder.

[0039] Example 4:

[0040] The only difference from Example 1 is that the broken ceramic tube material was not impregnated.

[0041] Example 5:

[0042] The only difference from Example 1 is that step S3 is performed with closed stirring at room temperature (25°C).

[0043] Example 6:

[0044] The difference from Example 1 is that step S2, in which 0.65 parts of montmorillonite powder and deionized water are mixed evenly and then added to the mixer, is not performed.

[0045] Comparative Example 1:

[0046] The only difference from Example 1 is that no broken ceramic tube material was added.

[0047] Comparative Example 2:

[0048] The only difference from Example 1 is that no refractory mortar was added.

[0049] Comparative Example 3:

[0050] The only difference from Example 1 is that no resin was added.

[0051] Environmental conditions: Temperature: 20.1℃, Humidity: 62%, Hardening time: 24h (Tensile, flexural and compressive strength conforms to standard: GB / T 2684-2009; Hot deformation fracture time was obtained by testing with a high-temperature compressive strength tester).

[0052] Table 1: Performance test results of the adhesives prepared in Examples 1-6 and Comparative Examples 1-3

[0053]

[0054]

[0055] In summary, the casting binder of this invention reuses broken ceramic tubes after use, protects the environment and reduces production costs. Adding an appropriate amount of broken ceramic tube material can make the connection between two sand molds tighter. Furthermore, the use of a mixture of water glass and resin can improve the bonding strength and high-temperature stability.

[0056] The embodiments described herein cover any points not exhaustively within the scope of the technical claims of this invention, as well as new technical solutions formed by equivalent substitutions of one or more technical features in the embodiments. These are all within the scope of the claims of this invention. Furthermore, in all listed or unlisted embodiments of this invention, each parameter in the same embodiment merely represents an instance (i.e., a feasible solution) of its technical solution, and there is no strict coordination or limitation relationship between the parameters. The parameters can be substituted for each other without violating axioms and the claims of this invention, unless otherwise stated.

[0057] The technical means disclosed in this invention are not limited to those described above, but also include technical solutions composed of any combination of the above technical features. The above descriptions are specific embodiments of this invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

[0058] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A binder for foundry use, characterized by, The binder comprises the following raw materials in parts by weight: 16-18 parts montmorillonite powder, 6-6.5 parts deionized water, 8-15 parts broken ceramic tubes, 3-5 parts furan resin, 23-25 ​​parts water glass, 18-23 parts refractory mortar, and 2-5 parts water; The particle size of montmorillonite powder is 250-280 mesh; The particle size of the crushed ceramic tube material is 50-70 mesh; The broken ceramic pipe material is treated with impregnation. The impregnation treatment specifically involves immersing the broken ceramic tube material in a mixture of water glass and water. The mass ratio of water glass to water is 1:(4-4.5). The method for preparing the casting binder includes the following steps: S1. First, mix 3-5 wt% montmorillonite powder with deionized water evenly and then put it into a mixer. S2. Then mix the furan resin and water glass, heat and seal the mixture before putting it into a mixer. S3. Add refractory mortar, remaining montmorillonite powder, water, and broken porcelain tubes into the mixer in sequence, and mix all the raw materials evenly to obtain a binder. The heating and stirring temperature is 80-95℃, and the time is 2-5 minutes.

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