A method for producing a foundry sand binder

Abstract

The present application relates to a kind of foundry molding sand binder preparation method, which uses pitch, distillation residue in the production process of diacetone acrylamide, water, emulsifier, catalyst and the like as raw material to prepare foundry molding sand binder, and the preparation method is to add pitch, distillation residue in the production process of diacetone acrylamide, vegetable oil, catalyst, emulsifier, water into a mixing tank with stirrer, and high-speed stirring under heating until uniform, which can be used.The present application has simple process, convenient operation, less reaction equipment, solves the environmental pollution problem caused by the discharge of distillation residue in the production process of diacetone acrylamide, and provides cheap raw material for foundry binder production, and the prepared binder has good performance.

Description

Technical Field

[0001] This invention relates to a method for preparing a casting sand binder. Background Technology

[0002] The casting industry is a crucial foundation for national economic development. A large amount of equipment manufacturing relies on casting. Before some mechanical equipment can be molded, sand cores must first be made before molten steel or iron is poured into the molds created from the sand cores. Sand cores are made by self-hardening or heating and baking a mixture of high-purity quartz sand and binders. Therefore, the manufacture of sand cores requires a large number of different types of binders depending on the requirements. More complex sand cores in casting widely use vegetable oil binders such as tung oil and linseed oil. To reduce costs, slag oil binders are also used. All these binders require a heating and baking process. The advantage is that the waste sand cores after casting have good collapsibility and are easily broken and reused. In recent years, room-temperature self-hardening sand processes have been widely adopted, such as acid-cured furan resin self-hardening sand; organic ester-cured alkaline phenolic resin self-hardening sand; and organic ester-cured water glass self-hardening sand. For furan resin self-hardening sand technology, my country began research in the 1970s and large-scale application in the mid-1980s. Numerous suppliers of raw materials and equipment have accumulated rich production and technical experience, making it the most widely used and technologically mature resin self-hardening sand technology in my country. Long-term use has proven that furan resin self-hardening sand is very effective and successful in the production of cast iron parts. In the production of cast steel parts, most manufacturers use it for small to medium-sized or batch production, with fewer manufacturers using it for large-scale castings. Furthermore, furan resin sand also presents some problems in cast steel production, such as a strong pungent odor during production and a tendency for hot cracking and surface micro-cracks in the produced parts. For alkaline phenolic resin sand technology, research began abroad in the 1980s and widespread application began in the 1990s. Domestic research began in the late 1980s and its application has been gradually promoted. Because it overcomes some inherent drawbacks of furan resin sand technology, it has gained recognition in the domestic foundry industry and is mainly used for the production of low-alloy steel or high-alloy steel castings and ductile iron castings with higher quality requirements. Its usage is gradually expanding. However, its recycled sand is not as good as furan resin sand, resulting in relatively higher production costs. Water glass organic ester self-hardening sand originated in the United States in 1967, but gradually developed into a new casting process in the 1990s. This process does not have the disadvantages of furan resin sand and also possesses some advantages of alkali phenolic resin sand, with better environmental friendliness. However, problems such as recycled sand have not been well resolved, and the sand collapsibility, surface quality, and dimensional accuracy of the produced castings are still not as good as those of resin sand technology. Although the three self-hardening sand processes each have their advantages and disadvantages, they can all produce high-quality and dimensionally accurate cast steel products, meeting the needs of different markets and different types of cast steel production.

[0003] In summary, depending on the requirements and the different molding sand processes used in casting, a wide variety of binders are employed, and their application methods vary. Currently, vegetable oils such as rice bran oil, linseed oil, and modified asphalt are still used in some complex castings, such as gearboxes. Therefore, it remains necessary to continuously develop high-performance, low-cost casting binders to meet the needs of the casting industry in order to reduce the cost of binders while ensuring casting quality.

[0004] This invention prepares a molding sand binder for casting using raw materials such as distillation residue from the production process of asphalt and diacetone acrylamide, water, emulsifier, catalyst, and linseed oil. Its main components are asphalt and diacetone acrylamide distillation residue (hereinafter referred to as distillation residue). The preparation cost is low, which not only provides the casting industry with a relatively inexpensive and high-performance binder product, but also enables the comprehensive utilization of distillation residue and prevents the pollution of distillation residue to the environment. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention discloses a method for preparing casting sand binder, which solves the problems in existing technologies.

[0006] This invention is achieved through the following technical solution:

[0007] A method for preparing a foundry sand binder includes the following steps:

[0008] The basic raw materials include vegetable oil, industrial asphalt, distillation residue, catalyst, emulsifier, water, etc.

[0009] The preparation method is carried out in a reaction vessel with a heating function. The material of the reaction vessel is stainless steel, carbon steel, enamel, etc., with carbon steel being preferred. The order of adding raw materials is as follows: water, emulsifier, vegetable oil, industrial asphalt, distillation residue, and catalyst. The temperature of the water is 60-90℃, preferably 65-90℃, and even more preferably 70-90℃. The preheating temperature of the asphalt is 80-150℃, preferably 95-150℃, and even more preferably 100-150℃. The stirring speed is 1500-10000 rpm, preferably 2000-10000 rpm, and even more preferably 2500-10000 rpm.

[0010] The emulsifiers include: nonylphenol polyoxyethylene ethers, fatty alcohol polyoxyethylene ethers, higher fatty acid salts, betaines, alkyl sulfonates, or any other emulsifiers with a hydrophilic-lipophilic balance (HLB) value of 3 to 15. Nonylphenol polyoxyethylene ether emulsifiers (OP type) with an HLB value of 3 to 15, preferably 4 to 15, are preferred. The amount added is 2 to 15% of the weight of the binder, preferably 4 to 15%, and even more preferably 6 to 15%.

[0011] The catalyst is manganese dioxide, potassium permanganate, potassium dichromate, lead monoxide, lead dioxide, potassium perchlorate, sodium perchlorate, etc., preferably manganese dioxide, and the amount of manganese dioxide added is 0.5-5% of the weight of the binder, preferably 1-5%.

[0012] The vegetable oils used are soybean oil, cottonseed oil, linseed oil, tung oil, rapeseed oil, and any other vegetable oils with an iodine value of 80 or higher. Linseed oil is preferred, and the amount of linseed oil added is 5-50% of the weight of the binder, more preferably 7.5-50%, and even more preferably 10-50%.

[0013] The water used is tap water, deionized water, or purified water, preferably tap water. The amount of water added is 10-50% of the weight of the binder, preferably 20-50%, and even more preferably 25-50%. The amount of distillation residue added is 10-50% of the weight of the binder, preferably 20-50%, and even more preferably 30-50%.

[0014] The industrial asphalt mentioned therein includes petroleum asphalt, tar asphalt, natural asphalt, and preferably petroleum asphalt. Among the petroleum asphalt, grades with relatively low softening points, such as AH-50, AH-70, AH-90, and AH-110, are selected, with AH-50 grade asphalt being preferred.

[0015] Currently, kerosene is generally used as a solvent in the preparation of oily binders in the foundry industry to reduce the viscosity of the binder. The beneficial effects of this invention are reflected in:

[0016] This invention uses water as a solvent to reduce viscosity, avoiding environmental pollution caused by the evaporation of organic solvents during the heating and drying process. The raw material is the distillation residue discharged during the production of diacetone acrylamide, which avoids the environmental harm of the residue and makes good use of it, reduces the amount of vegetable oil used, provides binder products for the foundry industry, and reduces production costs.

[0017] In the foundry industry, the amount of sand core binder used is very large. Although vegetable oil binders such as tung oil, linseed oil, and rice bran oil have excellent performance, their usage cost is relatively high. In order to reduce costs, asphalt, mixed fatty acids, oleic acid, and other residues from the purification and distillation process containing unsaturated fatty acids are added to these vegetable oils. While reducing costs, these added components also increase the viscosity of the binder. During use, this is beneficial to improving the wet viscosity of the oil sand and ensuring the dimensional stability of the sand core before drying. At the same time, the addition of distillation residues of oleic acid with a relatively high iodine value also plays a certain role in improving the strength of the sand core. Therefore, it is necessary to appropriately add some high-molecular-weight mixtures to reduce the cost of foundry binders and improve their performance.

[0018] Diacetone acrylamide is an important polymer monomer. During its production, the crude product is often separated using vacuum distillation. Because the molecule contains unsaturated double bonds and nitrogen-hydrogen bonds, and the distillation temperature is relatively high, some monomers undergo various complex reactions during this process to generate highly viscous, brownish polymer compounds. These compounds cannot be effectively utilized and pollute the environment. In the past, they were often incinerated, resulting in waste. This invention uses these distillation residues, tung oil, linseed oil, water, emulsifiers, petroleum asphalt, catalysts, etc., as basic raw materials to prepare a molding sand binder for casting. This eliminates the environmental pollution caused by distillation residues, reduces the production cost of the binder, and achieves twice the result with half the effort.

[0019] In this invention, water is used instead of organic solvents as a dispersant or diluent to reduce the viscosity of the binder. To increase the dispersion performance of distillation residue and asphalt in water, a nonylphenol polyoxyethylene ether emulsifier is added. The good emulsifying properties of this emulsifier allow the asphalt and distillation residue with relatively high viscosity to be well dispersed to form a relatively stable emulsion.

[0020] This invention uses a high-speed shear mixer to stir the mixture at high speed. The high-speed shear stirring of the mixture system results in good compatibility between the various components, and the resulting water-based binder has better storage stability. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and are therefore only examples, and should not be used to limit the scope of protection of the present invention.

[0022] This invention uses asphalt, distillation residue from the production process of diacetone acrylamide, water, emulsifier, vegetable oil, catalyst, etc. as raw materials to prepare a molding sand binder for casting. The preparation method is as follows: a certain amount of water, emulsifier, and catalyst are added in proportion to a reaction tank that can be heated and kept at a certain temperature. The mixture is stirred until completely dissolved and then heated to 70-90°C. In another reaction tank, asphalt, distillation residue, and vegetable oil are heated together in proportion to 120°C. Then, the stirrer of the first reaction tank is turned on, and the material from the second reaction tank is slowly added to the first reaction tank at a high speed. The mixture is stirred at high speed for 20 minutes, then stirring is stopped, and the mixture is cooled to room temperature.

[0023] Example 1

[0024] Accurately weigh 30 kg of tap water, 8 kg of OP-4 emulsifier, and 2 kg of manganese dioxide into a 150-liter reaction tank (1) equipped with a heater and stirrer. Heat the mixture to 80°C with stirring. Weigh 20 kg of linoleic acid, 15 kg of diacetone acrylamide distillation residue, and 25 kg of AH-50 asphalt, and add them to another 100-liter reaction tank (2) equipped with an electric heater and stirrer. This second reaction tank is connected to the first reaction tank via pipes and a pump. Slowly heat the mixture to 130°C and maintain the temperature for 0.5 hours with stirring. Start the stirrer in the first reaction tank and adjust the speed to 8000 rpm. While stirring at high speed, slowly add the materials from the second reaction tank (2) that have been heated to 130°C to the first reaction tank via a pipe pump. After adding all the materials, continue stirring and maintaining the temperature for 0.5 hours, then allow it to cool naturally to room temperature.

[0025] Example 2

[0026] Accurately weigh 30 kg of tap water, 8 kg of emulsifier, and 2 kg of potassium permanganate, and place them in a 150-liter reaction tank (1) equipped with a heater and stirrer. Heat the mixture to 80°C with stirring. Weigh 20 kg of linoleic acid, 15 kg of diacetone acrylamide distillation residue, and 25 kg of AH-50 asphalt, and add them to another 100-liter reaction tank (2) equipped with an electric heater and stirrer. This second reaction tank is connected to the first reaction tank via pipes and a pump. Slowly heat the mixture to 130°C and maintain the temperature for 0.5 hours with stirring. Start the stirrer in the first reaction tank and adjust the speed to 8000 rpm. While stirring at high speed, slowly add the materials from the second reaction tank (2) that have been heated to 130°C to the first reaction tank via a pipe pump. After adding all the materials, continue stirring and maintaining the temperature for 0.5 hours, then allow it to cool naturally to room temperature.

[0027] Example 3

[0028] Accurately weigh 30 kg of tap water, 8 kg of emulsifier, and 2 kg of lead monoxide, and place them in a 150-liter reaction tank (1) equipped with a heater and stirrer. Heat the mixture to 80°C with stirring. Weigh 25 kg of linoleic acid, 15 kg of diacetone acrylamide distillation residue, and 20 kg of AH-50 asphalt, and add them to another 100-liter reaction tank (2) equipped with an electric heater and stirrer. This second reaction tank is connected to the first reaction tank via pipes and a pump. Slowly heat the mixture to 130°C and maintain the temperature for 0.5 hours with stirring. Start the stirrer in the first reaction tank and adjust the speed to 8000 rpm. While stirring at high speed, slowly add the materials from the second reaction tank (2) that have been heated to 130°C to the first reaction tank via a pipe pump. After adding all the materials, continue stirring and maintaining the temperature for 0.5 hours, then allow it to cool naturally to room temperature.

[0029] Example 4

[0030] Accurately weigh 30 kg of tap water, 4 kg of emulsifier, 4 kg of OP-4 emulsifier, and 2 kg of lead monoxide, and place them in a 150-liter reaction tank (1) equipped with heating and a stirrer. Heat the mixture to 85°C with stirring. Weigh 20 kg of linoleic acid, 20 kg of diacetone acrylamide distillation residue, and 20 kg of AH-70 asphalt, and add them to another 100-liter reaction tank (2) equipped with electric heating and a stirrer. This second reaction tank is connected to the first reaction tank via pipes and a pump. Slowly heat the mixture to 135°C and maintain the temperature for 0.5 hours with stirring. Start the stirrer in the first reaction tank and adjust the speed to 8000 rpm. While stirring at high speed, slowly add the materials from the second reaction tank (2) that have been heated to 135°C to the first reaction tank via a pipe pump. After adding all the materials, continue stirring and maintaining the temperature for 0.5 hours, then allow it to cool naturally to room temperature.

[0031] Example 5

[0032] Accurately weigh 30 kg of tap water, 4 kg of emulsifier, 4 kg of OP-4 emulsifier, and 2 kg of lead monoxide, and place them in a 150-liter reaction tank (1) equipped with heating and a stirrer. Heat the mixture to 85°C with stirring. Weigh 25 kg of tung oil, 20 kg of diacetone acrylamide distillation residue, and 15 kg of AH-90 asphalt, and add them to another 100-liter reaction tank (2) equipped with electric heating and a stirrer. This second reaction tank is connected to the first reaction tank via pipes and a pump. Slowly heat the mixture to 135°C and maintain the temperature for 0.5 hours with stirring. Start the stirrer in the first reaction tank and adjust the speed to 8000 rpm. While stirring at high speed, slowly add the materials in the second reaction tank (2) that have been heated to 135°C to the first reaction tank via a pipe pump. After adding all the materials, continue stirring and maintaining the temperature for 0.5 hours, then allow it to cool naturally to room temperature.

[0033] Example 6

[0034] Accurately weigh 35 kg of tap water, 4 kg of emulsifier, 4 kg of OP-4 emulsifier, and 2 kg of manganese dioxide, and place them in a 150-liter reaction tank (1) equipped with heating and a stirrer. Heat the mixture to 85°C with stirring. Weigh 25 kg of tung oil, 15 kg of diacetone acrylamide distillation residue, and 15 kg of AH-50 asphalt, and add them to another 100-liter reaction tank (2) equipped with electric heating and a stirrer. This second reaction tank is connected to the first reaction tank via pipes and a pump. Slowly heat the mixture to 135°C and maintain the temperature for 0.5 hours with stirring. Start the stirrer in the first reaction tank and adjust the speed to 8000 rpm. While stirring at high speed, slowly add the materials in the second reaction tank (2) that have been heated to 135°C to the first reaction tank via a pipe pump. After adding all the materials, continue stirring and maintaining the temperature for 0.5 hours, then allow it to cool naturally to room temperature.

[0035] Example 7

[0036] Accurately weigh 35 kg of tap water, 8 kg of calcium stearate, and 2 kg of potassium dichromate, and place them in a 150-liter reaction tank (1) equipped with a heater and stirrer. Heat the mixture to 85°C with stirring. Weigh 25 kg of soybean oil, 15 kg of diacetone acrylamide distillation residue, and 15 kg of AH-50 asphalt, and add them to another 100-liter reaction tank (2) equipped with an electric heater and stirrer. This second reaction tank is connected to the first reaction tank via pipes and a pump. Slowly heat the mixture to 135°C and maintain the temperature for 0.5 hours with stirring. Turn on the stirrer in the first reaction tank and adjust the speed to 8000 rpm. While stirring at high speed, slowly add the materials in the second reaction tank (2) that have been heated to 135°C to the first reaction tank via a pipe pump. After adding all the materials, continue stirring and maintaining the temperature for 0.5 hours, then allow it to cool naturally to room temperature.

[0037] Example 8

[0038] Add 2000 kg of standard quartz sand, 20 kg of clay, and 80 kg of any one of the binders from Examples 1-7 to a small sand mixer. Start the sand mixer to mix them thoroughly. Add the uniformly mixed sand to the figure-eight sample module and place it in an oven at 215°C. After drying for 1 hour, take out the figure-eight sample, cool it to room temperature, and test it with a universal strength tester. The tensile strength is greater than 1.5 MPa.

[0039] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. For those skilled in the art, any alternative improvements or modifications made to the embodiments of the present invention fall within the protection scope of the present invention.

[0040] Any aspects of this invention not described in detail are well-known to those skilled in the art.

Claims

1. A method for preparing a casting sand binder, characterized in that: Its basic raw materials include vegetable oil, industrial asphalt, distillation residue, catalyst, emulsifier, and water; In a heating and heat-insulating reaction vessel one, add a certain amount of water, emulsifier, and catalyst in proportion. Start the stirrer and stir until completely dissolved, then heat to 70-90℃. In another reaction vessel two, heat asphalt, distillation residue, and vegetable oil together in proportion to 120℃. Then, start the stirrer of reaction vessel one and slowly add the material from reaction vessel two to reaction vessel one at high speed. After stirring evenly, cool to room temperature. The raw material is the distillation residue discharged during the production of diacetone acrylamide, and the amount added is 30-50% of the weight of the binder.

2. The preparation method according to claim 1, characterized in that: The vegetable oil is one of soybean oil, cottonseed oil, linseed oil, tung oil, or rapeseed oil, and the amount added is 7.5-50% of the weight of the binder.

3. The preparation method according to claim 1, characterized in that: The emulsifier is a nonylphenol polyoxyethylene ether emulsifier, and the amount added is 6-15% of the weight of the binder.

4. The preparation method according to claim 1, characterized in that: The catalyst is one of manganese dioxide, potassium permanganate, potassium dichromate, lead monoxide, lead dioxide, potassium perchlorate, and sodium perchlorate, and the amount added is 1-5% of the weight of the binder.