A composite modified foundry water glass sand and its preparation method

Abstract

This invention discloses a composite modifier for water glass sand used in casting and a method for preparing modified water glass sand, relating to the field of water glass sand technology. The raw material composition of the composite modifier for water glass sand provided by this invention includes zinc oxide powder, magnesium silicate, lithium dihydrogen phosphate, potassium pyrophosphate, and calcium stearate. Using ceramic sand, quartz powder, and slag as sand materials, water glass binder and the composite modifier are added to obtain composite-modified water glass sand for casting. The addition of the composite modifier makes the binder film and binder bridges denser and stronger, and improves the moisture resistance of the water glass sand. When heated to high temperatures, the binder film is broken, forming numerous pores and cracks, thereby reducing the residual strength of the water glass sand. The composite-modified water glass sand for casting provided by this invention has excellent comprehensive performance, overcoming the problems of low room temperature strength, short service life, and poor collapsibility of traditional water glass sand. Furthermore, the preparation method is simple and environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of water glass sand technology, and more specifically, to a composite modifier for water glass sand used in casting, modified water glass sand used in casting, and a preparation method thereof. Background Technology

[0002] Water glass, as an inorganic binder for casting, is widely used in the foundry industry due to its strong bonding force, good acid and heat resistance, lack of harmful gas production during use, and low cost. Water glass sand, in particular, is considered the molding sand most likely to achieve green casting goals due to its high strength, simple production process, and lack of environmental pollution.

[0003] However, water glass sand also has many drawbacks. For example, the water glass binder is prone to aging during storage, resulting in lower strength of the prepared water glass sand; it has poor moisture resistance, easily absorbing moisture from the air, and its strength drops sharply with prolonged storage; water glass sand has high residual strength and poor collapsibility, making demolding of castings difficult and resulting in extremely low reuse rates. These problems have long plagued foundry workers, restricting the application and development of water glass sand.

[0004] To effectively improve the performance of water glass sand, modifiers are often added between the water glass binder and the raw sand during the production process. Currently, commonly used modifiers mainly include inorganic powders (metal oxides, inorganic salts) and high-molecular-weight organic esters, which can effectively improve certain aspects of the water glass sand's performance. However, while improving the bonding strength of the water glass sand, extending its usable time and reducing its residual strength—that is, obtaining water glass sand with excellent overall performance—is often not ideal.

[0005] In view of this, the present invention is proposed to solve the above-mentioned technical problems. Summary of the Invention

[0006] The first objective of this invention is to provide a composite modifier that can effectively improve the properties of water glass sand in casting. By using this composite modifier to modify the water glass binder, the bonding strength of the water glass binder can be improved, the usable time of the casting water glass sand can be extended, and the collapsibility of the casting water glass sand can be improved.

[0007] The second objective of this invention is to provide a casting water glass sand mold prepared based on the above-mentioned composite modifier, so as to solve the problems of low room temperature strength, short service life and poor collapsibility of existing casting water glass sand molds.

[0008] The third objective of this invention is to provide a method for preparing composite modified casting water glass sand, which is simple and environmentally friendly.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0010] This invention provides a composite modifier for water glass sand used in foundry, composed of inorganic and organic substances, including zinc oxide powder, magnesium silicate, lithium dihydrogen phosphate, potassium pyrophosphate, and calcium stearate. It is composed of the following raw materials by weight percentage: 5%-15% nano zinc oxide powder, 5%-15% magnesium silicate, 15%-25% lithium dihydrogen phosphate, 20%-40% potassium pyrophosphate, and 25%-35% calcium stearate, with the total content of the above components being 100%.

[0011] This invention also provides a composite modified foundry water glass sand, comprising ceramic sand, a modified water glass binder, quartz powder, and slag. It is composed of the following raw materials by weight percentage: 90%-94% ceramic sand, 2%-3% modified water glass binder, 2%-4% quartz powder, and 1%-3% slag, with the total content of the above components being 100%. The modified water glass binder includes both a water glass binder and the aforementioned composite modifier. It is composed of the following raw materials by weight percentage: 70%-90% water glass binder and 10%-30% composite modifier.

[0012] This invention also provides a method for preparing composite modified casting water glass sand, the specific technical steps of which are as follows:

[0013] a. Weigh each raw material in the water glass sand composite modifier according to the formula amount, then crush the inorganic raw material to 100-140 mesh, and then mix each raw material thoroughly for 3-5 minutes to obtain the composite modifier.

[0014] b. After drying the composite modifier at 110℃-120℃ for 6-12 hours, mix it with the water glass binder, heat it to 60℃-70℃, and stir for 1-2 minutes to obtain the modified water glass binder.

[0015] c. Weigh out ceramic sand, quartz powder and slag according to the formula, then crush and grind them to 90-110 mesh, and then mix the raw materials thoroughly for 1-3 minutes to obtain mixture A;

[0016] d. Mix mixture A with the modified water glass binder, then stir and heat at 140℃-160℃ for 2-4 minutes to obtain modified water glass sand.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] (1) This invention provides a composite modifier for composite-modified casting water glass sand, comprising zinc oxide powder, magnesium silicate, lithium dihydrogen phosphate, potassium pyrophosphate, and calcium stearate. The addition of the composite modifier makes the adhesive film formed by the water glass binder denser and the sand particles more uniformly coated. The bonding bridges connecting adjacent sand particles are denser and stronger, thereby improving the room temperature strength of the water glass sand. Furthermore, by improving the water glass sand's resistance to moisture absorption, its usable time is extended. At high temperatures, by breaking the adhesive film, pores and cracks are formed, thereby reducing the residual strength of the water glass sand and improving its collapsibility.

[0019] (2) This invention provides a composite modified water glass sand for casting, wherein the modified water glass sand for casting is obtained by mixing water glass binder with the above-mentioned composite modifier, ceramic sand, quartz powder and slag in a specific ratio. Compared with unmodified water glass sand, this modified water glass sand has improved room temperature strength, and its service life and collapsibility are also significantly improved.

[0020] (3) This invention also provides a method for preparing the above-mentioned composite modified water glass sand for casting. The method involves first mixing the water glass sand composite modifier with the water glass sand binder, and then mixing it with other raw materials, and preparing the above-mentioned modified water glass sand for casting according to specific process parameters. The prepared modified water glass sand has good comprehensive performance; in addition, the preparation method has a simple process flow, is green and pollution-free, and has promising industrial application prospects. Detailed Implementation

[0021] The present invention will now be described in detail with reference to specific embodiments.

[0022] The composite modifier of the present invention is composed of the following raw materials by weight percentage: 5%-15% zinc oxide powder, 5%-15% magnesium silicate, 15%-25% lithium dihydrogen phosphate, 20%-40% potassium pyrophosphate, and 25%-35% calcium stearate, with the total content of the above components being 100%.

[0023] The composite modified casting water glass sand of the present invention comprises ceramic sand, modified water glass binder, quartz powder, and slag. It is composed of the following raw materials by weight percentage: 90%-94% ceramic sand, 2%-3% modified water glass binder, 2%-4% quartz powder, and 1%-3% slag, with the total content of the above components being 100%. The modified water glass sand binder is composed of the following raw materials by weight percentage: 80%-90% water glass binder and 10%-20% composite modifier, with the total content of the above components being 100%.

[0024] The preparation method of composite modified casting water glass sand is carried out according to the following steps:

[0025] a. Weigh each raw material in the water glass sand composite modifier according to the formula, then crush the raw materials to 100-140 mesh, and then mix the raw materials thoroughly for 3-5 minutes to obtain the composite modifier.

[0026] b. After drying the composite modifier at 110℃-120℃ for 6-12 hours, mix it with the water glass binder, heat it to 60℃-70℃, and stir for 1-2 minutes to obtain the modified water glass binder.

[0027] c. Weigh out ceramic sand, quartz powder and slag according to the formula, then crush and grind them to 90-110 mesh, and then mix the raw materials thoroughly for 1-3 minutes to obtain mixture A;

[0028] d. Mix mixture A with the modified water glass binder, then stir and heat at 140℃-160℃ for 2-4 minutes to obtain modified water glass sand.

[0029] In this invention, by rationally selecting and matching the proportions of each component of the composite modifier, the components work synergistically, resulting in a significant reduction in the residual strength of the water glass sand with the addition of the composite modifier, and a substantial improvement in its usable time and room temperature strength. In other words, the overall performance of the water glass sand is greatly improved.

[0030] In this invention, modified casting water glass sand is prepared by rationally selecting and matching the proportions of ceramic sand, modified water glass binder, quartz powder and slag, and its comprehensive performance is excellent.

[0031] Example 1

[0032] The composite modifier is composed of the following raw materials by weight percentage: 5% zinc oxide powder, 15% magnesium silicate, 25% lithium dihydrogen phosphate, 20% potassium pyrophosphate, and 35% calcium stearate, with the total content of the above components being 100%.

[0033] The composite modified casting water glass sand is composed of the following raw materials by weight percentage: 90% ceramic sand, 3% modified water glass binder, 4% quartz powder, and 3% slag, with the total content of the above components being 100%. The modified water glass sand binder is composed of the following raw materials by weight percentage: 80% water glass binder and 20% composite modifier.

[0034] Titanium oxide powder, magnesium silicate, lithium dihydrogen phosphate, potassium pyrophosphate, and calcium stearate in the composite modifier for casting water glass sand were crushed to 140 mesh, mixed according to the formula for 5 minutes, and then wet-milled to obtain the composite modifier. Acetone was used as the solvent during milling, with a weight ratio of composite modifier to acetone of 0.8:1; the ball mill speed was set to 170 r / min, and the milling time was 1 hour.

[0035] The composite modifier was dried in a forced-air drying oven, then mixed with water glass binder and heated to obtain the modified water glass binder. The drying temperature was 120℃, the drying time was 6 hours, the heating temperature was 70℃, and the stirring time was 1 minute.

[0036] After crushing ceramic sand, quartz powder and slag to 110 mesh, mix the raw materials according to the formula for 1 minute to obtain mixture A.

[0037] Mixture A and the modified water glass binder are stirred and heated until homogeneous, thus obtaining the composite modified casting water glass sand of the present invention. The heating temperature is 160°C, and the stirring time is 2 minutes.

[0038] Example 2

[0039] The composite modifier is composed of the following raw materials by weight percentage: 10% nano zinc oxide powder, 10% magnesium silicate, 20% lithium dihydrogen phosphate, 30% potassium pyrophosphate, and 30% calcium stearate, with the total content of the above components being 100%.

[0040] The composite modified casting water glass sand is composed of the following raw materials by weight percentage: ceramic sand 92%, modified water glass binder 2.5%, quartz powder 3%, and slag 2.5%, with the total content of the above components being 100%. The modified water glass sand binder is composed of the following raw materials by weight percentage: water glass binder 85%, and composite modifier 15%.

[0041] Titanium oxide powder, magnesium silicate, lithium dihydrogen phosphate, potassium pyrophosphate, and calcium stearate in the composite modifier for casting water glass sand were crushed to 120 mesh, mixed according to the formula for 4 minutes, and then wet-milled to obtain the composite modifier. Acetone was used as the solvent during milling, with a weight ratio of composite modifier to acetone of 0.82:1; the ball mill speed was set to 160 r / min, and the milling time was 1.5 h.

[0042] The composite modifier was dried in a forced-air drying oven, then mixed with water glass binder and heated to obtain the modified water glass binder. The drying temperature was 115℃, the drying time was 9 hours, the heating temperature was 65℃, and the stirring time was 1.5 minutes.

[0043] After crushing ceramic sand, quartz powder and slag to 100 mesh, mix the raw materials according to the formula for 1.5 minutes to obtain mixture A.

[0044] Mixture A is stirred and heated with a modified water glass binder until homogeneous, thus obtaining the composite modified casting water glass sand of the present invention. The heating temperature is 150°C, and the stirring time is 3 minutes.

[0045] Example 3

[0046] The composite modifier is composed of the following raw materials by weight percentage: 15% nano zinc oxide powder, 5% magnesium silicate, 15% lithium dihydrogen phosphate, 40% potassium pyrophosphate, and 25% calcium stearate, with the total content of the above components being 100%.

[0047] The composite modified casting water glass sand is composed of the following raw materials by weight percentage: ceramic sand 94%, modified water glass binder 2%, quartz powder 2%, and slag 2%, with the total content of the above components being 100%. The modified water glass sand binder is composed of the following raw materials by weight percentage: water glass binder 90%, and composite modifier 10%.

[0048] Titanium oxide powder, magnesium silicate, lithium dihydrogen phosphate, potassium pyrophosphate, and calcium stearate in the composite modifier for casting water glass sand were crushed to 100 mesh, mixed according to the formula for 3 minutes, and then wet-milled to obtain the composite modifier. Ethanol was used as the solvent during milling, and the weight ratio of the composite modifier to acetone was 0.86:1. The ball mill speed was set to 150 r / min, and the milling time was 2 hours.

[0049] The composite modifier was dried in a forced-air drying oven, then mixed with water glass binder and heated to obtain the modified water glass binder. The drying temperature was 110℃, the drying time was 12 hours, the heating temperature was 60℃, and the stirring time was 2 minutes.

[0050] After crushing ceramic sand, quartz powder and slag to 90 mesh, mix the raw materials according to the formula for 3 minutes to obtain mixture A.

[0051] Mixture A and the modified water glass binder are stirred and heated until homogeneous, thus obtaining the composite modified casting water glass sand of the present invention. The heating temperature is 140°C, and the stirring time is 4 minutes.

Claims

1. A composite modifier for composite modified casting water glass sand, characterized in that, The product is composed of the following raw materials by weight percentage: 5%-15% zinc oxide powder, 5%-15% magnesium silicate, 15%-25% lithium dihydrogen phosphate, 20%-40% potassium pyrophosphate, and 25%-35% calcium stearate, with the total content of the above components being 100%.

2. Foundry water glass sand modified with the composite modifier according to claim 1, characterized in that, The raw materials are composed of the following by weight percentage: ceramic sand 90%-94%, modified water glass binder 2%-3%, quartz powder 2%-4%, and slag 1%-3%, with the total content of the above components being 100%. The modified water glass binder, including water glass binder and the above-mentioned composite modifier, is composed of the following raw materials by weight percentage: water glass binder 70%-90%, and composite modifier 10%-30%.

3. The method for preparing casting water glass sand modified with the composite modifier according to claim 2, characterized in that, The main steps include: a. Weigh each raw material in the water glass sand composite modifier according to the formula amount, then crush the inorganic raw material to 100-140 mesh, and then mix each raw material thoroughly for 3-5 minutes to obtain the composite modifier; b. After drying the composite modifier at 110℃-120℃ for 6-12 hours, mix it with the water glass binder, heat it to 60℃-70℃, and stir for 1-2 minutes to obtain the modified water glass binder. c. Weigh out ceramic sand, quartz powder and slag according to the formula, then crush and grind them to 90-110 mesh, and then mix the raw materials thoroughly for 1-3 minutes to obtain mixture A; d. Mix mixture A with the modified water glass binder, then stir and heat at 140℃-160℃ for 2-4 minutes to obtain modified water glass sand.