High-suspension-property composite casting coating and preparation method thereof

Abstract

The invention discloses a high-suspension composite casting coating and a preparation method thereof, the high-suspension composite casting coating comprises the following components by mass: 67-73 wt% of aggregate, 20-26 wt% of a solvent, 1-5 wt% of a suspending agent, 1-5 wt% of a binder, and 1-2 wt% of a combustion improver; the suspending agent is a composition of fumed silica, bentonite and alkyl ammonium salt. According to the high-suspension-property composite casting coating and the preparation method thereof, the compound suspending agent system and the composite aggregate system are adopted, and the alkyl ammonium salt and the composite aggregate system are added into the suspending agent system, so that the problems that aggregate is poor in dispersity, easy to settle, poor in rheological property and the like can be effectively solved, and the coating is good in suspension property; the high-suspension-property composite casting coating is free of layering after being stored for a long time, good in rheological property and easy to apply, the coating quality is improved, meanwhile, the cost of the coating is reduced, and the prepared high-suspension-property composite casting coating can be suitable for production and molding of large steel castings.

Description

Technical Field

[0001] This invention belongs to the technical field of refractory coatings for casting. Specifically, this invention relates to a highly suspended composite casting coating and its preparation method. Background Technology

[0002] Currently, zircon powder coatings used in casting molding have the following technical drawbacks: First, due to the high density of zircon powder, traditional zircon powder coatings have poor suspension stability, easily settling, separating, and agglomerating in suspension systems. This necessitates frequent stirring before use, increasing labor intensity and making it difficult to ensure coating uniformity and stability. Separation of the coating results in excessive binder in the upper layer and excessive powder in the lower layer, causing it to flow and accumulate during application, or leading to uneven powder concentration and defects on the casting surface such as "ant holes," "wrinkles," and "sand adhesion." Second, traditional coatings often improve suspension by adding inorganic gels such as bentonite, but this significantly increases coating viscosity, leading to poor flowability, uneven coating thickness, and flow marks on complex molds. Furthermore, zircon powder is currently mainly imported, resulting in high costs.

[0003] An ideal casting coating should possess good thixotropy, meaning it should be in a gel state when standing to prevent sedimentation, and in a fluid state when stirred or applied for ease of handling. In the prior art, patent CN115647283A discloses a casting coating with good suspension properties and its preparation method. This coating uses zircon powder as refractory aggregate, silica sol as binder, a compound suspending agent, and water as a carrier. The compound suspending agent is composed of bentonite and additives. The additives are a mixture of sodium hydroxymethyl cellulose with a high degree of substitution (HMC) and sodium alginate in a 5:1~2 mass ratio to improve the coating's suspension properties. However, the high-substituted HMC is obtained by crushing bamboo to obtain bamboo powder, which is then processed. This process is cumbersome, and the carrier used in this coating is water. The impact on the suspension properties of alcohol-based coatings and zircon powder composite coatings is not mentioned. Patent CN118751850A discloses an alcohol-based rheology coating and its preparation method, belonging to the field of casting coating technology. It is composed of the following raw materials: 80-90% composite refractory aggregate mud, 1-3% modified inorganic suspending agent, 1-3% functional additives, and 4-15% first alcohol solvent. The suspension rate of the alcohol-based rheology coating is 99.2-99.6%, the penetration depth is 0.8-1.2mm, and the gas generation is 7.8-8.2mL / g. It reduces the use of solvent, thereby reducing the risk of strength reduction due to excessive solvent penetration into the sand core during the coating process. It also further reduces the gas generation of the coating and inhibits the occurrence of porosity defects in the casting. However, the patent does not focus on the suspension performance. CN119407097A discloses a cast iron sand mold coating and its preparation method, relating to the field of casting sand mold coatings. The cast iron sand mold coating of this invention is composed of the following raw materials: refractory filler, liquid carrier, suspending agent, binder, and additives; the weight percentage of each raw material is: refractory filler 65-70%, liquid carrier 19-25%, suspending agent 2-4%, binder 4.4-5.5%, and additives 2.4-3%; the refractory filler is composed of magnesia powder, zircon powder, and graphite powder; the magnesia powder is composed of lightweight magnesia powder and heavy magnesia powder. This patent focuses on sulfur impermeability. Summary of the Invention

[0004] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0005] To achieve these objectives and other advantages of the present invention, a highly suspending composite casting coating is provided, comprising, by weight percentage: 67-73 wt% aggregate, 20-26 wt% solvent, 1-5 wt% suspending agent, 1-5 wt% binder, and 1-2 wt% combustion improver; The suspending agent is a composition of fumed silica, bentonite, and alkyl ammonium salt.

[0006] Preferably, the aggregate is a compound of two or more of zircon powder, zirconium corundum, and white corundum; the particle size of the aggregate is 200 mesh or 325 mesh.

[0007] Preferably, the solvent is a mixture of two or more of methanol, ethanol, isopropanol, and water; in the high-suspension composite casting coating, the mass percentage of ethanol is 10-20 wt% and the mass percentage of isopropanol is 12-23 wt%.

[0008] Preferably, the bentonite is BASF bentonite ATT-50 or sodium bentonite, and the alkyl ammonium salt is BYK-9076; in the high-suspension composite casting coating, the mass percentage of fumed silica is 0.2~0.3wt%, the mass percentage of bentonite is 2.5~3.5wt%, and the mass percentage of alkyl ammonium salt is 0.3~0.4wt%.

[0009] Preferably, the bentonite undergoes organic modification, the method being: By weight, 10 parts of sodium-based bentonite were added to 100-150 parts of water and stirred at an ultrasonic power of 200-300 W for 15-30 min until uniformly dispersed. Then, 0.3-0.6 parts of polyethylene glycol were added and stirred at room temperature for 20-40 min. 0.03-0.1 parts of acetic acid were added to the stirred solution and stirred at room temperature for 10-30 min. Then, 20-30 parts of dodecyltrimethylammonium chloride were added and stirred at 60-80℃ for 2-4 h. The modified sodium-based bentonite was observed to separate from the water. The mixture was filtered, washed with deionized water, and vacuum dried at 60-85℃ for 4-12 h to obtain organically modified bentonite. During this process, the stirring power was 300-500 rpm / min.

[0010] Preferably, the adhesive is a composition of rosin resin and polyvinyl butyral.

[0011] Preferably, the combustion aid is 6# solvent oil or 120# solvent oil.

[0012] This invention also provides a method for preparing a highly suspended composite casting coating, comprising the following steps: Step 1: Add solvent to the production container, followed by binder and combustion aid, and stir at 800~1000 rpm / min for 5~10 min; Step 2: Add a suspending agent to the mixture obtained in Step 1 and stir at a speed of 1000~1200 rpm / min for 5~10 min; Step 3: Add aggregate to the mixture obtained in Step 2, and stir at a speed of 1400~2000 rpm / min for 20~30 min to obtain a high-suspension composite casting coating.

[0013] Preferably, in steps one, two, and three, the stirring container is cooled by circulating cooling water.

[0014] This invention provides at least the following beneficial effects: It offers a high-suspension composite casting coating and its preparation method, employing a compound suspending agent system and a composite aggregate system. By adding alkyl ammonium salts and the composite aggregate system to the suspending agent system, problems such as poor aggregate dispersibility, easy sedimentation, and poor rheological properties can be effectively solved, resulting in coatings with good suspension properties, no stratification during long-term storage, good rheological properties, and ease of application, thus improving coating quality and reducing coating costs. The prepared high-suspension composite casting coating is suitable for use in the production and molding of large cast steel parts. Furthermore, organic modification of the bentonite in the compound suspending agent system further improves suspension properties, reduces viscosity, and increases fluidity.

[0015] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation

[0016] The present invention will now be described in further detail so that those skilled in the art can implement it based on the description.

[0017] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0018] Example 1 A method for preparing a highly suspended composite casting coating includes the following steps: Step 1: Add 24.4 wt% solvent (8.0 wt% methanol, 15.0 wt% ethanol, and 1.4 wt% water) to the production container by mass percentage, followed by 1.3 wt% binder (1.1 wt% rosin resin and 0.2 wt% polyvinyl butyral) and 1.1 wt% combustion aid (1.1 wt% No. 6 solvent oil), and stir at 1000 rpm / min for 5 min. Step 2: Add 3.7 wt% of suspending agent (0.3 wt% fumed silica, 3.0 wt% BASF bentonite ATT-50, 0.4 wt% alkyl ammonium salt BYK-9076) to the mixture obtained in Step 1, and stir at 1200 rpm / min for 10 min. Step 3: Add 69.5 wt% of aggregate (15 wt% of 200 mesh zircon powder, 35 wt% of 325 mesh zircon powder, and 19.5 wt% of 200 mesh white corundum) to the mixture obtained in Step 2, and stir at 1500 rpm / min for 20 min to obtain a high-suspension composite casting coating.

[0019] Example 2 A method for preparing a highly suspended composite casting coating includes the following steps: Step 1: Add 24.4 wt% solvent (10.0 wt% methanol, 13.0 wt% ethanol, and 1.4 wt% water) to the production container by mass percentage, followed by 1.3 wt% binder (1.1 wt% rosin resin and 0.2 wt% polyvinyl butyral) and 1.1 wt% combustion aid (1.1 wt% No. 6 solvent oil). Stir at 1000 rpm / min for 5 minutes. Step 2: Add 3.7 wt% of suspending agent (0.3 wt% fumed silica, 3.0 wt% BASF bentonite ATT-50, 0.4 wt% alkyl ammonium salt BYK-9076) to the mixture obtained in Step 1, and stir at 1200 rpm / min for 10 min. Step 3: Add 69.5 wt% aggregate (10 wt% 200 mesh zircon powder, 30 wt% 325 mesh zircon powder, and 29.5 wt% 200 mesh white corundum) to the mixture obtained in Step 2, and stir at 1500 rpm / min for 20 min to obtain a high-suspension composite casting coating.

[0020] Example 3 A method for preparing a highly suspended composite casting coating includes the following steps: Step 1: Add 24.4 wt% solvent (11.0 wt% methanol, 12.0 wt% ethanol, and 1.4 wt% water) to the production container by mass percentage, followed by 1.3 wt% binder (1.1 wt% rosin resin and 0.2 wt% polyvinyl butyral) and 1.1 wt% combustion aid (1.1 wt% No. 6 solvent oil). Stir at 1000 rpm / min for 5 minutes. Step 2: Add 3.6 wt% of suspending agent (0.3 wt% fumed silica, 3.0 wt% BASF bentonite ATT-50, 0.3 wt% alkyl ammonium salt BYK-9076) to the mixture obtained in Step 1, and stir at 1200 rpm / min for 10 min. Step 3: Add 69.6 wt% of aggregate (10 wt% of 200 mesh zircon powder, 20 wt% of 325 mesh zircon powder, and 39.6 wt% of 200 mesh white corundum) to the mixture obtained in Step 2, and stir at 1500 rpm / min for 20 min to obtain a high-suspension composite casting coating.

[0021] Example 4 A method for preparing a highly suspended composite casting coating includes the following steps: Step 1: Add 24.4 wt% solvent (12.0 wt% methanol, 11.0 wt% ethanol, and 1.4 wt% water) to the production container by mass percentage, followed by 1.3 wt% binder (1.1 wt% rosin resin and 0.2 wt% polyvinyl butyral) and 1.1 wt% combustion aid (1.1 wt% No. 6 solvent oil). Stir at 1000 rpm / min for 5 minutes. Step 2: Add 3.6 wt% of suspending agent (0.3 wt% fumed silica, 3.0 wt% BASF bentonite ATT-50, 0.3 wt% alkyl ammonium salt BYK-9076) to the mixture obtained in Step 1, and stir at 1200 rpm / min for 10 min. Step 3: Add 69.6 wt% aggregate (20 wt% 325 mesh zircon powder and 49.6 wt% 200 mesh white corundum) to the mixture obtained in Step 2, and stir at 1500 rpm / min for 20 min to obtain a high-suspension composite casting coating.

[0022] Example 5 A method for preparing a highly suspended composite casting coating includes the following steps: Step 1: Add 24.4 wt% solvent (11.0 wt% ethanol, 12.0 wt% isopropanol, 1.4 wt% water) to the production container by mass percentage, followed by 1.3 wt% binder (1.1 wt% rosin resin, 0.2 wt% polyvinyl butyral) and 1.1 wt% combustion aid (1.1 wt% 120# solvent oil), and stir at 1000 rpm / min for 5 min; Step 2: Add 3.6 wt% of suspending agent (0.3 wt% fumed silica, 3.0 wt% BASF bentonite ATT-50, 0.3 wt% alkyl ammonium salt BYK-9076) to the mixture obtained in Step 1, and stir at 1200 rpm / min for 10 min. Step 3: Add 69.6 wt% aggregate (20 wt% 325 mesh zircon powder and 49.6 wt% 200 mesh zirconium corundum) to the mixture obtained in Step 2, and stir at 1500 rpm / min for 20 min to obtain a high suspension composite casting coating.

[0023] Example 6 A method for preparing a highly suspended composite casting coating includes the following steps: Step 1: Add 24.4 wt% solvent (10.0 wt% methanol, 13.0 wt% ethanol, and 1.4 wt% water) to the production container by mass percentage, followed by 1.3 wt% binder (1.1 wt% rosin resin and 0.2 wt% polyvinyl butyral) and 1.1 wt% combustion aid (1.1 wt% No. 6 solvent oil). Stir at 1000 rpm / min for 5 minutes. Step 2: Add 3.7 wt% of suspending agent (0.3 wt% fumed silica, 3.0 wt% sodium bentonite, and 0.4 wt% alkyl ammonium salt BYK-9076) to the mixture obtained in Step 1, and stir at 1200 rpm / min for 10 min. Step 3: Add 69.5 wt% aggregate (10 wt% 200 mesh zircon powder, 30 wt% 325 mesh zircon powder, and 29.5 wt% 200 mesh white corundum) to the mixture obtained in Step 2, and stir at 1500 rpm / min for 20 min to obtain a high-suspension composite casting coating.

[0024] Example 7 A method for preparing a highly suspended composite casting coating includes the following steps: Step 1: Add 24.4 wt% solvent (10.0 wt% methanol, 13.0 wt% ethanol, and 1.4 wt% water) to the production container by mass percentage, followed by 1.3 wt% binder (1.1 wt% rosin resin and 0.2 wt% polyvinyl butyral) and 1.1 wt% combustion aid (1.1 wt% No. 6 solvent oil). Stir at 1000 rpm / min for 5 minutes. Step 2: Add 3.7 wt% of suspending agent (0.3 wt% fumed silica, 3.0 wt% organic modified bentonite, and 0.4 wt% alkyl ammonium salt BYK-9076) to the mixture obtained in Step 1, and stir at 1200 rpm / min for 10 min. Step 3: Add 69.5 wt% aggregate (10 wt% 200 mesh zircon powder, 30 wt% 325 mesh zircon powder, and 29.5 wt% 200 mesh white corundum) to the mixture obtained in Step 2, and stir at 1500 rpm / min for 20 min to obtain a high-suspension composite casting coating. The organically modified bentonite is bentonite that has undergone organic modification, specifically through the following method: By weight, 10 parts of sodium-based bentonite were added to 100 parts of water and ultrasonically stirred at 300 W for 20 min until uniformly dispersed. Then, 0.3 parts of polyethylene glycol were added and stirred at room temperature for 30 min. 0.03 parts of acetic acid were added to the stirred solution and stirred at room temperature for 20 min. Then, 25 parts of dodecyltrimethylammonium chloride were added and stirred at 60 °C for 3 h. It was observed that the modified sodium-based bentonite separated from the water. The mixture was filtered, washed with deionized water, and vacuum dried at 70 °C for 6 h to obtain organically modified bentonite. The stirring power was 400 rpm / min throughout the process.

[0025] Comparative Example 1 A method for preparing a composite casting coating includes the following steps: Step 1: Add 24.4 wt% solvent (10.0 wt% methanol, 13.0 wt% ethanol, and 1.4 wt% water) to the production container by mass percentage, followed by 1.3 wt% binder (1.1 wt% rosin resin and 0.2 wt% polyvinyl butyral) and 1.1 wt% combustion aid (1.1 wt% No. 6 solvent oil). Stir at 1000 rpm / min for 5 minutes. Step 2: Add 3.7 wt% of suspending agent (0.3 wt% fumed silica, 3.2 wt% BASF bentonite ATT-50, 0.2 wt% alkyl ammonium salt BYK-9076) to the mixture obtained in Step 1, and stir at 1200 rpm / min for 10 min. Step 3: Add 69.5 wt% aggregate (10 wt% 200 mesh zircon powder, 30 wt% 325 mesh zircon powder, and 29.5 wt% 200 mesh white corundum) to the mixture obtained in Step 2, and stir at 1500 rpm / min for 20 min to obtain the composite casting coating.

[0026] Comparative Example 2 A method for preparing a composite casting coating includes the following steps: Step 1: Add 24.4 wt% solvent (10.0 wt% methanol, 13.0 wt% ethanol, and 1.4 wt% water) to the production container by mass percentage, followed by 1.3 wt% binder (1.1 wt% rosin resin and 0.2 wt% polyvinyl butyral) and 1.1 wt% combustion aid (1.1 wt% No. 6 solvent oil). Stir at 1000 rpm / min for 5 minutes. Step 2: Add 3.7 wt% of suspending agent (0.3 wt% fumed silica and 3.4 wt% BASF bentonite ATT-50) to the mixture obtained in Step 1, and stir at 1200 rpm / min for 10 min. Step 3: Add 69.5 wt% aggregate (10 wt% 200 mesh zircon powder, 30 wt% 325 mesh zircon powder, and 29.5 wt% 200 mesh white corundum) to the mixture obtained in Step 2, and stir at 1500 rpm / min for 20 min to obtain the composite casting coating.

[0027] Comparative Example 3 A method for preparing a composite casting coating includes the following steps: Step 1: Add 24.4 wt% solvent (18.0 wt% methanol, 5.0 wt% ethanol, and 1.4 wt% water) to the production container by mass percentage, followed by 1.3 wt% binder (1.1 wt% rosin resin and 0.2 wt% polyvinyl butyral) and 1.1 wt% combustion aid (1.1 wt% No. 6 solvent oil), and stir at 1000 rpm / min for 5 min. Step 2: Add 3.7 wt% of suspending agent (0.3 wt% fumed silica, 3.0 wt% BASF bentonite ATT-50, 0.4 wt% alkyl ammonium salt BYK-9076) to the mixture obtained in Step 1, and stir at 1200 rpm / min for 10 min. Step 3: Add 69.5 wt% aggregate (10 wt% 200 mesh zircon powder, 30 wt% 325 mesh zircon powder, and 29.5 wt% 200 mesh white corundum) to the mixture obtained in Step 2, and stir at 1500 rpm / min for 20 min to obtain the composite casting coating.

[0028] Comparative Example 4 A method for preparing a composite casting coating includes the following steps: Step 1: Add 24.4 wt% solvent (23.0 wt% methanol, 1.4 wt% water) to the production container by mass percentage, followed by 1.3 wt% binder (1.1 wt% rosin resin, 0.2 wt% polyvinyl butyral) and 1.1 wt% combustion aid (1.1 wt% No. 6 solvent oil), and stir at 1000 rpm / min for 5 min; Step 2: Add 3.7 wt% of suspending agent (0.3 wt% fumed silica, 3.0 wt% BASF bentonite ATT-50, 0.4 wt% alkyl ammonium salt BYK-9076) to the mixture obtained in Step 1, and stir at 1200 rpm / min for 10 min. Step 3: Add 69.5 wt% aggregate (10 wt% 200 mesh zircon powder, 30 wt% 325 mesh zircon powder, and 29.5 wt% 200 mesh white corundum) to the mixture obtained in Step 2, and stir at 1500 rpm / min for 20 min to obtain the composite casting coating.

[0029] Comparative Example 5 A method for preparing a highly suspended composite casting coating includes the following steps: Step 1: Add 24.4 wt% solvent (23.0 wt% ethanol, 1.4 wt% water) to the production container by mass percentage, followed by 1.3 wt% binder (1.1 wt% rosin resin, 0.2 wt% polyvinyl butyral) and 1.1 wt% combustion aid (1.1 wt% 120# solvent oil), and stir at 1000 rpm / min for 5 min; Step 2: Add 3.6 wt% of suspending agent (0.3 wt% fumed silica, 3.0 wt% BASF bentonite ATT-50, 0.3 wt% alkyl ammonium salt BYK-9076) to the mixture obtained in Step 1, and stir at 1200 rpm / min for 10 min. Step 3: Add 69.6 wt% aggregate (20 wt% 325 mesh zircon powder and 49.6 wt% 200 mesh zirconium corundum) to the mixture obtained in Step 2, and stir at 1500 rpm / min for 20 min to obtain a high suspension composite casting coating.

[0030] The composite casting coatings prepared in Examples 1-7 and Comparative Examples 1-5 were tested for Baumé degree and suspension properties, and the results are shown in Table 1.

[0031] Table 1 The test results of Example 2 and Comparative Example 1 show that the suspension of the coating deteriorates when the alkyl ammonium salt content is less than 0.3 wt%. The test results of Example 2 and Comparative Example 2 show that the coating has a high Baume degree, is relatively viscous, and has poor rheological properties when there is no alkyl ammonium salt. Therefore, the preferred range of alkyl ammonium salt is 0.3~0.4 wt%.

[0032] As can be seen from Comparative Examples 3-4 compared with Example 2, when the ethanol content is less than 5.0 wt%, the Baumé degree of the coating also decreases and the suspension stability deteriorates. Therefore, the preferred range for ethanol is 10-20 wt%.

[0033] As can be seen from Comparative Example 5 compared to Example 5, ethanol has poorer suspension properties than isopropanol. When ethanol is used entirely, the Baumé degree also decreases, and the suspension stability deteriorates. Therefore, the preferred range for isopropanol in zircon powder-zirconia corundum coatings is 12~23 wt%.

[0034] Compared with Example 6, Example 7 shows that the coating prepared with modified bentonite has a slightly lower Baume degree, increased fluidity, and better suspension stability. This is because in Example 7, sodium-based bentonite was organically modified. After dispersion with polyethylene glycol, surface conditioning with acetic acid, and organic coating with quaternary ammonium salt, the organically modified bentonite with surface polarity can dissolve well in the solvent and can be quickly and uniformly dispersed after addition. At the same time, the modified bentonite can reduce the viscosity of the system, enhance suspension stability, and is not prone to sedimentation and stratification.

[0035] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A highly suspending composite casting coating, characterized in that, By mass percentage, it includes the following components: 67-73 wt% aggregate, 20-26 wt% solvent, 1-5 wt% suspending agent, 1-5 wt% binder, and 1-2 wt% combustion improver; The suspending agent is a composition of fumed silica, bentonite, and alkyl ammonium salt.

2. The high-suspension composite casting coating as described in claim 1, characterized in that, The aggregate is a compound of two or more of zircon powder, zirconium corundum, and white corundum; the particle size of the aggregate is 200 mesh or 325 mesh.

3. The high-suspension composite casting coating as described in claim 1, characterized in that, The solvent is a mixture of two or more of methanol, ethanol, isopropanol, and water; in the high-suspension composite casting coating, the mass percentage of ethanol is 10-20 wt% and the mass percentage of isopropanol is 12-23 wt%.

4. The high-suspension composite casting coating as described in claim 1, characterized in that, The bentonite is BASF bentonite ATT-50 or sodium bentonite, and the alkyl ammonium salt is BYK-9076. In the high-suspension composite casting coating, the mass percentage of fumed silica is 0.2~0.3wt%, the mass percentage of bentonite is 2.5~3.5wt%, and the mass percentage of alkyl ammonium salt is 0.3~0.4wt%.

5. The high-suspension composite casting coating as described in claim 1, characterized in that, The bentonite is organically modified using the following method: Sodium-based bentonite was added to water and ultrasonically stirred until uniformly dispersed. Then, polyethylene glycol was added and stirred at room temperature for 20-40 minutes. Acetic acid was added to the stirred solution and stirred at room temperature for 10-30 minutes. Dodecyltrimethylammonium chloride was then added and stirred at 60-80°C for 2-4 hours. The modified sodium-based bentonite was observed to separate from the water. The mixture was then filtered, washed, and vacuum dried to obtain organically modified bentonite.

6. The high-suspension composite casting coating as described in claim 1, characterized in that, The adhesive is a composition of rosin resin and polyvinyl butyral.

7. The high-suspension composite casting coating as described in claim 1, characterized in that, The combustion aid is either No. 6 solvent oil or No. 120 solvent oil.

8. A method for preparing a high-suspension composite casting coating as described in claims 1-7, characterized in that, Includes the following steps: Step 1: Add solvent to the production container, followed by binder and combustion aid, and stir at 800~1000 rpm / min for 5~10 min; Step 2: Add a suspending agent to the mixture obtained in Step 1 and stir at a speed of 1000~1200 rpm / min for 5~10 min; Step 3: Add aggregate to the mixture obtained in Step 2, and stir at a speed of 1400~2000 rpm / min for 20~30 min to obtain a high-suspension composite casting coating.

9. The preparation method of the high-suspension composite casting coating as described in claim 8, characterized in that, In steps one, two, and three, the stirring container is cooled by circulating cooling water.

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