Preparation method of high-compactness zircon powder for casting

Abstract

The invention provides a preparation method of high-compactness zircon powder for casting, and belongs to the technical field of zircon powder.The preparation method comprises the following steps that raw materials are weighed, all zircon sand is subjected to acid pickling and impurity removal, then part of zircon sand obtained after acid pickling is taken for high-temperature heating, the zircon sand is taken out and then rapidly poured into a normal-temperature pretreatment solution, and pretreated cold-extracted zircon sand is obtained; the pre-treatment solution is a water solution obtained after three kinds of mixed monomers including acrylamide, acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid are subjected to a polymerization reaction, the pre-treatment solution and the remaining zircon sand subjected to acid pickling are evenly mixed, ball milling is conducted, after ball milling is completed, the mixture and other raw materials are put into a mixer to be mixed, the high-compactness zircon powder for casting is obtained, and the pre-treatment solution is a water solution obtained after three kinds of mixed monomers including acrylamide, acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid are subjected to a polymerization reaction. Parts of zircon sand are subjected to quenching treatment through the pretreatment solution, the obtained composite-graded zircon powder has reasonable particle size distribution, effective embedding extrusion between particles can be achieved, and the finally prepared material has high density.

Description

Technical Field

[0001] The present invention belongs to the technical field of zircon powder, and particularly relates to a preparation method of high-density zircon powder for casting. Background Art

[0002] The investment casting shell is a mold shell for the formation of high-temperature liquid metal, which is made of multiple layers of refractory powders. The refractory powder on the surface layer is in direct contact with the molten metal, and the material is required to have high refractoriness, small expansion coefficient, high high-temperature strength, and small residual strength after cooling.

[0003] Zirconium materials are the most commonly used refractory materials for the surface layer of investment casting shells, and have advantages such as non-adhesion to sand and low residual strength. With the gradual depletion of zirconium materials resources in recent years, the price has also risen. Therefore, how to utilize limited raw materials to make them play a greater value is an urgent problem for those skilled in the art. The better the density of the surface layer material of the shell, the higher the mechanical properties, and the better the surface finish of the final casting. In the prior art, through ball milling or different particle size combinations, although a particle group containing multiple particle sizes can be obtained to achieve a certain density, the grading form is single, the compatibility between particles is poor, and at the same time, the mobility and dispersion ability of the particles are limited, making it difficult to form effective interlocking, and it is difficult for the surface layer of the shell to reach a high density. Summary of the Invention

[0004] To solve the problems in the background art, the present invention provides a preparation method of high-density zircon powder for casting, in which the compatibility between particles of different particle sizes is good, and at the same time, the particles have high mobility and dispersion ability, and can form a good interlocking effect with each other, so that the surface layer material of the shell has a high density.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A preparation method of high-density zircon powder for casting, comprising the following steps:

[0007] A1. Weigh the following raw materials by weight: 100 parts of zircon sand, 8 - 12 parts of silica powder, 12 - 16 parts of inorganic binder, 2 - 4 parts of sodium silicate, and 2.8 - 3.2 parts of wetting agent;

[0008] A2. Pickle and remove impurities from the zircon sand, then take a part of the pickled zircon sand and place it in a high-temperature furnace for heating. The heating temperature is 750 - 850 °C, keep it warm for 20 - 40 min, take it out and quickly pour it into a pretreatment solution at room temperature, and cool it to room temperature to obtain pretreated quenched zircon sand;

[0009] A3. Mix the pre-treated quenched zircon sand obtained in step S2 evenly with the remaining pickled zircon sand, put it into a ball mill for ball milling at a speed of 120 - 180 r / min for 2 - 4 h. After ball milling, a composite graded powder is obtained;

[0010] A4. Mix the composite graded powder obtained in step S3 with other raw materials in step S1 in a mixer for 10 - 20 min to obtain high-density zircon powder for casting;

[0011] Among them, the pre-treatment solution in step A2 is an aqueous solution after the polymerization reaction of three mixed monomers of acrylamide, acrylic acid, and 2-acrylamido-2-methylpropanesulfonic acid.

[0012] Furthermore, the preparation of the pre-treatment solution includes the following steps:

[0013] S1. Mix acrylamide, acrylic acid, and 2-acrylamido-2-methylpropanesulfonic acid to obtain a mixed monomer, and dissolve the mixed monomer in deionized water to obtain a monomer mixed solution, where the mass concentration of the monomer mixed solution is 25 - 35%;

[0014] S2. Take 100 parts of the monomer mixed solution, heat it to 60 - 70 °C, add 0.2 - 1 part of initiator and 0.5 - 1.5 parts of titanate, adjust the pH value to 6.5 - 7.5 with an alkaline solution, and under nitrogen protection, stir and react for 4 - 8 h to obtain the pre-treatment reaction solution;

[0015] S3. Dilute the pre-treatment reaction solution 3 - 5 times with deionized water and stir evenly to obtain the pre-treatment solution.

[0016] Furthermore, in step A1, the particle size of zircon sand is 60 - 100 mesh, and the particle size of silica powder is 200 - 320 mesh.

[0017] Furthermore, in step A1, the inorganic binder is a mixture of 500-mesh kaolin and 500-mesh feldspar powder with a mass ratio of 10:3 - 5.

[0018] Furthermore, in step A1, the wetting agent is an aqueous solution of dextrin powder with a concentration of 30 - 40%.

[0019] Furthermore, in step A2, the pickling solution is one or a mixture of two or more of a hydrochloric acid solution, a sulfuric acid solution, and a nitric acid solution with a concentration of 5 - 10%.

[0020] Furthermore, in step A2, the mass ratio of the zircon sand placed in the high-temperature furnace for heating to the total amount of pickled zircon sand is 50 - 60%.

[0021] Further, in step S1, the mass ratio of acrylamide, acrylic acid, and 2-acrylamido-2-methylpropanesulfonic acid is 10:4 - 6:2 - 3.

[0022] Further, in step S2, the initiator is one or a mixture of two or more of azobisisobutyronitrile, azobisisopentanenitrile, and benzoyl peroxide.

[0023] Further, in step S2, the alkaline solution is one or a mixture of two of sodium hydroxide solution and potassium hydroxide solution.

[0024] This application has the following beneficial effects:

[0025] 1. Through quenching treatment, cracks and gaps can be generated in zircon sand, making it easier to break. After ball milling, small particle size graded particle groups can be formed. While for zircon sand without liquid quenching and cooling treatment, large particle size graded particle groups are obtained after ball milling. The two are mixed to obtain composite graded particles. A reasonable particle size distribution enables the particles to cooperate with each other, obtaining a higher density.

[0026] 2. The pretreatment solution can make the dispersion of small particle size graded particle groups more uniform, avoid their agglomeration, improve the density between powder bodies. In addition, hydrophilic groups can be introduced, enabling the inorganic powder to have a high adsorption capacity for wetting agents. During the heating process, the wetting agent forms pores, giving a certain space for movement to the small particle size graded particle groups, so that they are closely connected with the large particle size graded particle groups. Finally, they are filled and wrapped by the flowing binder, forming an effective interlocking between different graded particle groups and achieving a high density inside the material.

[0027] 3. During the cold extraction process, the high-temperature zircon sand particles are in direct contact with the low-temperature pretreatment solution. The pretreatment solution around the zircon sand particles generates instant high temperature, making it have a high surface activity and being able to fully penetrate into the crack and gap of the zircon sand particles, thus forming a complete coating on the small particle size powder body. At the same time, the deep penetration of the pretreatment solution is conducive to the extension and expansion of cracks. Therefore, the simultaneous cold extraction process and pretreatment solution are helpful to improve the quenching and coating effects of the pretreatment solution on the small particle size graded particle groups, and can further improve the density of the material. Specific Embodiments

[0028] The following further elaborates on this application with reference to examples.

[0029] The raw materials of the examples and comparative examples of this application are all ordinary commercially available products unless otherwise specified.

[0030] Example 1

[0031] A preparation method of high-density zircon powder for casting includes the following steps:

[0032] A1. Weigh the following raw materials by weight: 100 parts of zircon sand, 10 parts of silica powder, 14 parts of inorganic binder, 3 parts of sodium silicate and 3 parts of wetting agent. The particle size of zircon sand is 80 mesh, the particle size of silica powder is 240 mesh, the inorganic binder is a mixture of 500-mesh kaolin and 500-mesh feldspar powder with a mass ratio of 10:4, and the wetting agent is an aqueous solution of dextrin powder with a concentration of 35%;

[0033] A2. Carry out acid washing and impurity removal on zircon sand. The acid washing solution is a hydrochloric acid solution with a concentration of 8%. Then, take 55% of the total amount of acid-washed zircon sand and place it in a high-temperature furnace for heating. The heating temperature is 800 °C, keep it warm for 30 min, take it out and quickly pour it into the pretreatment solution at room temperature, and soak for 6 h to obtain pretreated quenched zircon sand;

[0034] A3. Mix the pretreated quenched zircon sand obtained in step S2 with the remaining acid-washed zircon sand evenly, put it into a ball mill for ball milling. The ball milling speed is 120 r / min, and the ball milling time is 4 h. After ball milling is completed, a composite graded powder is obtained;

[0035] A4. Mix the composite graded powder obtained in step S3 with other raw materials in step S1 in a mixer for 15 min to obtain high-density zircon powder for casting.

[0036] The preparation of the pretreatment solution includes the following steps:

[0037] S1. Mix acrylamide, acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid to obtain a mixed monomer. The mass ratio of acrylamide, acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid is 10:5:2.5. Dissolve the mixed monomer in deionized water to obtain a monomer mixed solution, and the mass concentration of the monomer mixed solution is 30%;

[0038] S2. Take 100 parts of the monomer mixed solution and heat it to 65 °C, add 0.6 parts of azobisisobutyronitrile and 1 part of titanate, adjust the pH value to 7.0 with sodium hydroxide solution, and stir and react for 6 h under nitrogen protection to obtain the pretreatment reaction solution;

[0039] S3. Dilute the pretreatment reaction solution 4 times with deionized water and stir evenly to obtain the pretreatment solution.

[0040] Example 2

[0041] A method for preparing high-density zircon powder for casting includes the following steps:

[0042] A1. Weigh the following raw materials by weight: 100 parts of zircon sand, 8 parts of silica powder, 12 parts of inorganic binder, 2 parts of sodium silicate, and 2.8 parts of wetting agent. The particle size of zircon sand is 60 mesh, the particle size of silica powder is 200 mesh, the inorganic binder is a mixture of 500-mesh kaolin and 500-mesh feldspar powder with a mass ratio of 10:3, and the wetting agent is an aqueous solution of dextrin powder with a concentration of 30%.

[0043] A2. Conduct acid washing and impurity removal on zircon sand. The acid washing solution is a sulfuric acid solution with a concentration of 5%. Then, take 50% of the total amount of acid-washed zircon sand and place it in a high-temperature furnace for heating. The heating temperature is 750°C, and keep it warm for 20 minutes. After taking it out, quickly pour it into the pretreatment solution at room temperature and soak for 6 hours to obtain pretreated quenched zircon sand.

[0044] A3. Mix the pretreated quenched zircon sand obtained in step S2 with the remaining acid-washed zircon sand evenly, put it into a ball mill for ball milling. The ball milling speed is 120 r / min, and the ball milling time is 4 hours. After the ball milling is completed, a composite graded powder is obtained.

[0045] A4. Mix the composite graded powder obtained in step S3 with other raw materials in step S1 in a mixer for 10 minutes to obtain high-density zircon powder for casting.

[0046] The preparation of the pretreatment solution includes the following steps:

[0047] S1. Mix acrylamide, acrylic acid, and 2-acrylamido-2-methylpropanesulfonic acid to obtain a mixed monomer. The mass ratio of acrylamide, acrylic acid, and 2-acrylamido-2-methylpropanesulfonic acid is 10:4:2. Dissolve the mixed monomer in deionized water to obtain a monomer mixed solution, and the mass concentration of the monomer mixed solution is 25%.

[0048] S2. Take 100 parts of the monomer mixed solution and heat it to 60°C. Add 0.2 parts of azobisisovaleronitrile and 0.5 parts of titanate. Adjust the pH value to 6.5 with potassium hydroxide solution. Under nitrogen protection, stir and react for 4 hours to obtain the pretreatment reaction solution.

[0049] S3. Dilute the pretreatment reaction solution with deionized water by 3 times and stir evenly to obtain the pretreatment solution.

[0050] Example 3

[0051] A preparation method of high-density zircon powder for casting includes the following steps:

[0052] A1. Weigh the following raw materials by weight parts: 100 parts of zircon sand, 12 parts of silica powder, 16 parts of inorganic binder, 4 parts of sodium silicate and 3.2 parts of wetting agent. The particle size of zircon sand is 100 mesh, the particle size of silica powder is 320 mesh, the inorganic binder is a mixture of kaolin and feldspar powder with a particle size of 500 mesh in a mass ratio of 10:5, and the wetting agent is an aqueous solution of dextrin powder with a concentration of 40%.

[0053] A2. Carry out acid washing and impurity removal on zircon sand. The acid washing solution is a nitric acid solution with a concentration of 5%. Then, take 60% of the total amount of acid-washed zircon sand and place it in a high-temperature furnace for heating. The heating temperature is 850 °C, keep it warm for 20 min, take it out and quickly pour it into the pretreatment solution at room temperature, and soak it for 6 h to obtain pretreated quenched zircon sand.

[0054] A3. Mix the pretreated quenched zircon sand obtained in step S2 with the remaining acid-washed zircon sand evenly, put it into a ball mill for ball milling. The ball milling speed is 180 r / min, and the ball milling time is 2 h. After ball milling is completed, a composite graded powder is obtained.

[0055] A4. Mix the composite graded powder obtained in step S3 with other raw materials in step S1 in a mixer for 20 min to obtain high-density zircon powder for casting.

[0056] The preparation of the pretreatment solution includes the following steps:

[0057] S1. Mix acrylamide, acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid to obtain a mixed monomer. The mass ratio of acrylamide, acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid is 10:6:3. Dissolve the mixed monomer in deionized water to obtain a monomer mixed solution, and the mass concentration of the monomer mixed solution is 35%.

[0058] S2. Take 100 parts of the monomer mixed solution and heat it to 70 °C, add 1 part of benzoyl peroxide and 1.5 parts of titanate, adjust the pH value to 7.5 with sodium hydroxide solution, and stir and react for 8 h under nitrogen protection to obtain the pretreatment reaction solution.

[0059] S3. Dilute the pretreatment reaction solution 5 times with deionized water and stir evenly to obtain the pretreatment solution.

[0060] Example 4

[0061] A preparation method of high-density zircon powder for casting includes the following steps:

[0062] A1. Weigh the following raw materials by weight parts: 100 parts of zircon sand, 8 parts of silica powder, 16 parts of inorganic binder, 2 parts of sodium silicate, and 3.2 parts of wetting agent. The particle size of zircon sand is 60 mesh, the particle size of silica powder is 320 mesh, the inorganic binder is a mixture of 500-mesh kaolin and 500-mesh feldspar powder with a mass ratio of 10:3, and the wetting agent is an aqueous solution of dextrin powder with a concentration of 35%.

[0063] A2. Conduct acid washing and impurity removal on the zircon sand. The acid washing solution is a hydrochloric acid solution with a concentration of 10%. Then, take 50% of the total amount of the acid-washed zircon sand and place it in a high-temperature furnace for heating. The heating temperature is 750 °C, keep it warm for 30 min, take it out and quickly pour it into the pretreatment solution at room temperature, and soak for 6 h to obtain the pretreated quenched zircon sand.

[0064] A3. Mix the pretreated quenched zircon sand obtained in step S2 with the remaining acid-washed zircon sand evenly, put it into a ball mill for ball milling. The ball milling speed is 180 r / min, and the ball milling time is 2 h. After the ball milling is completed, a composite gradation powder is obtained.

[0065] A4. Mix the composite gradation powder obtained in step S3 with other raw materials in step S1 in a mixer for 20 min to obtain the high-density zircon powder for casting.

[0066] The preparation of the pretreatment solution includes the following steps:

[0067] S1. Mix acrylamide, acrylic acid, and 2-acrylamido-2-methylpropanesulfonic acid to obtain a mixed monomer. The mass ratio of acrylamide, acrylic acid, and 2-acrylamido-2-methylpropanesulfonic acid is 10:4:2. Dissolve the mixed monomer in deionized water to obtain a monomer mixed solution, and the mass concentration of the monomer mixed solution is 35%.

[0068] S2. Take 100 parts of the monomer mixed solution and heat it to 65 °C. Add 0.8 parts of azobisisobutyronitrile and 0.8 parts of titanate. Adjust the pH value to 7.0 with potassium hydroxide solution. Under nitrogen protection, stir and react for 6 h to obtain the pretreatment reaction solution.

[0069] S3. Dilute the pretreatment reaction solution 5 times with deionized water and stir evenly to obtain the pretreatment solution.

[0070] Example 5

[0071] A preparation method of high-density zircon powder for casting includes the following steps:

[0072] A1. Weigh the following raw materials by weight: 100 parts of zircon sand, 12 parts of silica powder, 12 parts of inorganic binder, 4 parts of sodium silicate, and 3.2 parts of wetting agent. The particle size of zircon sand is 100 mesh, the particle size of silica powder is 320 mesh, the inorganic binder is a mixture of 500-mesh kaolin and 500-mesh feldspar powder with a mass ratio of 10:4, and the wetting agent is an aqueous solution of dextrin powder with a concentration of 40%.

[0073] A2. Carry out acid washing and impurity removal on zircon sand. The acid washing solution is a 10% nitric acid solution. Then, take 55% of the total amount of acid-washed zircon sand and place it in a high-temperature furnace for heating. The heating temperature is 800 °C, keep it warm for 30 min, take it out and quickly pour it into the pretreatment solution at room temperature, and soak for 6 h to obtain pretreated quenched zircon sand.

[0074] A3. Mix the pretreated quenched zircon sand obtained in step S2 with the remaining acid-washed zircon sand evenly, put it into a ball mill for ball milling. The ball milling speed is 150 r / min, and the ball milling time is 3 h. After ball milling is completed, a composite graded powder is obtained.

[0075] A4. Mix the composite graded powder obtained in step S3 with other raw materials in step S1 in a mixer for 10 min to obtain high-density zircon powder for casting.

[0076] The preparation of the pretreatment solution includes the following steps:

[0077] S1. Mix acrylamide, acrylic acid, and 2-acrylamido-2-methylpropanesulfonic acid to obtain a mixed monomer. The mass ratio of acrylamide, acrylic acid, and 2-acrylamido-2-methylpropanesulfonic acid is 10:6:3. Dissolve the mixed monomer in deionized water to obtain a monomer mixed solution, and the mass concentration of the monomer mixed solution is 35%.

[0078] S2. Take 100 parts of the monomer mixed solution and heat it to 65 °C. Add 0.5 parts of benzoyl peroxide and 0.5 parts of titanate. Adjust the pH value to 7.0 with potassium hydroxide solution. Under nitrogen protection, stir and react for 4 h to obtain the pretreatment reaction solution.

[0079] S3. Dilute the pretreatment reaction solution 4 times with deionized water and stir evenly to obtain the pretreatment solution.

[0080] Comparative Example 1

[0081] The difference between this comparative example and Example 1 is only that in step A2, water is used for quenching treatment and no soaking in the pretreatment solution is carried out, that is, the pretreatment solution is replaced with water. The specific content is as follows:

[0082] A method for preparing high-density zircon powder for casting includes the following steps:

[0083] A1. Weigh the following raw materials by weight: 100 parts of zircon sand, 10 parts of silica powder, 14 parts of inorganic binder, 3 parts of sodium silicate, and 3 parts of wetting agent. Among them, the particle size of zircon sand is 80 mesh, the particle size of silica powder is 240 mesh, the inorganic binder is a mixture of 500-mesh kaolin and 500-mesh feldspar powder with a mass ratio of 10:4, and the wetting agent is an aqueous solution of dextrin powder with a concentration of 35%;

[0084] A2. Carry out acid washing and impurity removal on the zircon sand. The acid washing solution is a hydrochloric acid solution with a concentration of 8%. Then, take 55% of the total amount of the acid-washed zircon sand and place it in a high-temperature furnace for heating. The heating temperature is 800 °C, keep it warm for 30 min, take it out and quickly pour it into water at room temperature, and soak for 6 h to obtain pretreated quenched zircon sand;

[0085] A3. Mix the pretreated quenched zircon sand obtained in step S2 with the remaining acid-washed zircon sand evenly, put it into a ball mill for ball milling. The ball milling speed is 120 r / min, and the ball milling time is 4 h. After ball milling is completed, a composite graded powder is obtained;

[0086] A4. Put the composite graded powder obtained in step S3 and other raw materials in step S1 into a mixer for mixing. The mixing time is 15 min to obtain high-density zircon powder for casting.

[0087] Comparative Example 2

[0088] The difference between this comparative example and Example 1 is only that in step A2, quenching treatment is not carried out, and only soaking in the pretreatment solution is carried out.

[0089] A preparation method of high-density zircon powder for casting includes the following steps:

[0090] A1. Weigh the following raw materials by weight: 100 parts of zircon sand, 10 parts of silica powder, 14 parts of inorganic binder, 3 parts of sodium silicate, and 3 parts of wetting agent. Among them, the particle size of zircon sand is 80 mesh, the particle size of silica powder is 240 mesh, the inorganic binder is a mixture of 500-mesh kaolin and 500-mesh feldspar powder with a mass ratio of 10:4, and the wetting agent is an aqueous solution of dextrin powder with a concentration of 35%;

[0091] A2. Carry out acid washing and impurity removal on the zircon sand. The acid washing solution is a hydrochloric acid solution with a concentration of 8%. Then, take 55% of the total amount of the acid-washed zircon sand and pour it into the pretreatment solution at room temperature, and soak for 6 h to obtain pretreated quenched zircon sand;

[0092] A3. Mix the pretreated quenched zircon sand obtained in step S2 with the remaining acid-washed zircon sand evenly, put it into a ball mill for ball milling. The ball milling speed is 120 r / min, and the ball milling time is 4 h. After ball milling is completed, a composite graded powder is obtained;

[0093] A4. Put the composite graded powder obtained in step S3 and other raw materials in step S1 into a mixer for mixing for 15 minutes to obtain highly dense zircon powder for casting.

[0094] Comparative Example 3

[0095] The difference between this comparative example and Example 1 is only that there is neither a quenching treatment process nor an immersion in the pretreatment solution.

[0096] A preparation method of highly dense zircon powder for casting includes the following steps:

[0097] A1. Weigh the following raw materials by weight: 100 parts of zircon sand, 10 parts of silica powder, 14 parts of inorganic binder, 3 parts of sodium silicate, and 3 parts of wetting agent. The particle size of the zircon sand is 80 mesh, the particle size of the silica powder is 240 mesh, the inorganic binder is a mixture of 500-mesh kaolin and 500-mesh feldspar powder with a mass ratio of 10:4, and the wetting agent is an aqueous solution of dextrin powder with a concentration of 35%;

[0098] A2. Carry out acid washing to remove impurities on the zircon sand. The acid washing solution is a hydrochloric acid solution with a concentration of 8%. Then put the zircon sand into a ball mill for ball milling. The ball milling speed is 120 r / min, and the ball milling time is 4 h. After the ball milling is completed, a composite graded powder is obtained;

[0099] A3. Put the composite graded powder obtained in step S2 and other raw materials in step S1 into a mixer for mixing for 15 minutes to obtain highly dense zircon powder for casting.

[0100] Comparative Example 4

[0101] The difference between this comparative example and Example 1 is only that the quenching treatment process of the pretreatment solution is carried out in two steps. First, water cooling is carried out, and then immersion in the pretreatment solution is carried out.

[0102] A preparation method of highly dense zircon powder for casting includes the following steps:

[0103] A1. Weigh the following raw materials by weight: 100 parts of zircon sand, 10 parts of silica powder, 14 parts of inorganic binder, 3 parts of sodium silicate, and 3 parts of wetting agent. The particle size of the zircon sand is 80 mesh, the particle size of the silica powder is 240 mesh, the inorganic binder is a mixture of 500-mesh kaolin and 500-mesh feldspar powder with a mass ratio of 10:4, and the wetting agent is an aqueous solution of dextrin powder with a concentration of 35%;

[0104] A2. Pickle and remove impurities from zircon sand. The pickling solution is a hydrochloric acid solution with a concentration of 8%. Then, take 55% of the total amount of pickled zircon sand and place it in a high-temperature furnace for heating. The heating temperature is 800 °C, keep it warm for 30 minutes, take it out and quickly pour it into water at room temperature, filter, and then soak it in the pretreatment solution for 6 hours to obtain pretreated quenched zircon sand;

[0105] A3. Mix the pretreated quenched zircon sand obtained in step S2 with the remaining pickled zircon sand evenly, put it into a ball mill for ball milling. The ball milling speed is 120 r / min, and the ball milling time is 4 hours. After ball milling is completed, a composite graded powder is obtained;

[0106] A4. Put the composite graded powder obtained in step S3 and other raw materials in step S1 into a mixer for mixing. The mixing time is 15 minutes to obtain high-density zircon powder for casting.

[0107] Effect verification

[0108] Press the high-density zircon powder for casting in Examples 1-5 and Comparative Examples 1-4 into green compacts. Sinter the green compacts at a high temperature. The sintering temperature is 1250 °C, the heating rate during sintering is 5 °C / min, and the holding time is 240 minutes to obtain specimen materials, and test the relative density of each group of specimen materials.

[0109] Table 1

[0110] <![CDATA[Relative density (g / cm 3 )]]> Example 1 2.32 Example 2 2.30 Example 3 2.28 Example 4 2.30 Example 5 2.31 Comparative Example 1 2.21 Comparative Example 2 2.13 Comparative Example 3 1.95 Comparative Example 4 2.24

[0111] Result analysis

[0112] Analyze Examples 1-5 and Comparative Examples 1-4, and combined with the data in Table 1, it can be seen that the preparation method of the high-density zircon powder for casting provided by the present invention quenches and cools part of the zircon sand through the pretreatment solution, and the obtained composite graded zircon powder has a reasonable particle size distribution, which can achieve effective interlocking between particles, making the finally prepared material have a higher density.

[0113] From Comprehensive Comparative Examples 1-3, it can be seen that the composite graded particles obtained by quenching and cooling part of the zircon sand can improve the relative density of the material. Soaking the zircon sand particles with the pretreatment solution can also improve the relative density of the material. Combining with Comparative Example 4, it can be seen that the simultaneous implementation of quenching and cooling treatment and the pretreatment solution, that is, quenching and cooling part of the zircon sand with the pretreatment solution, can further improve the quenching and coating effects of the pretreatment solution on the small particle size graded particle group, can produce a synergistic effect, and further improve the density of the material.

[0114] In addition, it should be noted that, for each of the specific technical features described in the above specific embodiments, they can be combined in any suitable way without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0115] In addition, any combinations can be made among various different embodiments of the present invention, as long as they do not violate the idea of the present invention, and they should also be regarded as the content disclosed by the present invention.

Claims

1. A preparation method of zircon powder with high density for casting, characterized in that, It includes the following steps: A1. Weigh the following raw materials by weight parts: 100 parts of zircon sand, 8 - 12 parts of silica powder, 12 - 16 parts of inorganic binder, 2 - 4 parts of sodium silicate, and 2.8 - 3.2 parts of wetting agent; A2. Carry out acid washing and impurity removal on all the zircon sand, then take part of the acid - washed zircon sand and place it in a high - temperature furnace for heating. The heating temperature is 750 - 850 °C, keep it warm for 20 - 40 min, take it out and quickly pour it into the pretreatment solution at room temperature, and cool it to room temperature to obtain the pretreated quenched zircon sand; A3. Mix the pretreated quenched zircon sand obtained in step S2 with the remaining acid - washed zircon sand evenly, put it into a ball mill for ball milling. The ball - milling speed is 120 - 180 r / min, and the ball - milling time is 2 - 4 h. After ball milling is completed, a composite - graded powder is obtained; A4. Put the composite - graded powder obtained in step S3 and other raw materials in step S1 into a mixer for mixing. The mixing time is 10 - 20 min to obtain the high - density zircon powder for casting; Among them, the pretreatment solution in step A2 is prepared from the aqueous solution after the polymerization reaction of three mixed monomers of acrylamide, acrylic acid, and 2 - acrylamido - 2 - methylpropanesulfonic acid.

2. The preparation method of the zircon powder with high density for casting according to claim 1, characterized in that, The preparation of the pretreatment solution in step A2 includes the following steps: S1. Mix acrylamide, acrylic acid, and 2 - acrylamido - 2 - methylpropanesulfonic acid to obtain a mixed monomer. Dissolve the mixed monomer in deionized water to obtain a monomer mixed solution, where the mass concentration of the mixed monomer in the monomer mixed solution is 25 - 35%; S2. Take 100 parts of the monomer mixed solution and heat it to 60 - 70 °C, add 0.2 - 1 part of initiator and 0.5 - 1.5 parts of titanate, adjust the pH value to 6.5 - 7.5 with an alkaline solution, and under nitrogen protection, stir and react for 4 - 8 h to obtain the pretreatment reaction solution; S3. Dilute the pretreatment reaction solution with deionized water by 3 - 5 times and stir evenly to obtain the pretreatment solution.

3. The preparation method of the zircon powder with high density for casting according to claim 1, characterized in that, In step A1, the particle size of the zircon sand is 60 - 100 mesh, and the particle size of the silica powder is 200 - 320 mesh.

4. The preparation method of the zircon powder with high density for casting according to claim 1, characterized in that, In step A1, the inorganic binder is a mixture of 500 - mesh kaolin and 500 - mesh feldspar powder with a mass ratio of 10:3 - 5.

5. The preparation method of the high-density zircon powder for casting according to claim 1, characterized in that, In step A1, the wetting agent is an aqueous solution of dextrin powder with a concentration of 30 - 40%.

6. The preparation method of the zircon powder with high density for casting according to claim 1, characterized in that, In step A2, the acid - washing solution is one or a mixture of two or more of a hydrochloric acid solution, a sulfuric acid solution, and a nitric acid solution with a concentration of 5 - 10%.

7. The preparation method of the zircon powder with high density for casting according to claim 1, characterized in that, In step A2, the mass ratio of the zircon sand placed in the high - temperature furnace for heating in the total amount of acid - washed zircon sand is 50 - 60%.

8. The preparation method of the high-density zircon powder for casting according to claim 2, characterized in that, In step S1, the mass ratio of acrylamide, acrylic acid, and 2 - acrylamido - 2 - methylpropanesulfonic acid is 10:4 - 6:2 - 3.

9. The preparation method of the high-density zircon powder for casting according to claim 2, characterized in that, In step S2, the initiator is one or a mixture of two or more of azobisisobutyronitrile, azobisisopentanenitrile, and benzoyl peroxide.

10. The preparation method of the zircon powder with high density for casting according to claim 2, characterized in that, In step S2, the alkaline solution is one or a mixture of two of sodium hydroxide solution and potassium hydroxide solution.