阅读说明：本技术 一种浇注成型的方坩埚及其制备方法 (Square crucible for casting molding and preparation method thereof ) 是由 蔡伟 殷若光 孙华云 李明京 蔡衍坤 殷佩如 于 2019-10-10 设计创作，主要内容包括：本发明涉及耐火材料制品技术领域,具体涉及一种浇注成型的方坩埚及其制备方法,所述方坩埚包括以下重量份数的原料：氧化铝粉10-30份、刚玉粉5-20份、3mm-1mm板状刚玉15-20份、20目刚玉颗粒10-20份、36目刚玉颗粒5-20份、80目刚玉颗粒5-10份、180目电熔莫来石10-20份、分散剂5-10份；方法包括除铁、搅拌、浇注、脱模、烘干、烧成步骤。本发明方坩埚具有耐高温、高强度、抗剥落、抗侵蚀、抗热震性好的特性,制备方法具有操作简单,不需要投入大型成型压机,投资少的特点。(The invention relates to the technical field of refractory material products, in particular to a square crucible formed by casting and a preparation method thereof, wherein the square crucible comprises the following raw materials in parts by weight: 10-30 parts of alumina powder, 5-20 parts of corundum powder, 15-20 parts of 3mm-1mm tabular corundum, 10-20 parts of 20-mesh corundum particles, 5-20 parts of 36-mesh corundum particles, 5-10 parts of 80-mesh corundum particles, 10-20 parts of 180-mesh fused mullite and 5-10 parts of dispersing agent; the method comprises the steps of iron removal, stirring, casting, demolding, drying and firing. The square crucible has the characteristics of high temperature resistance, high strength, stripping resistance, erosion resistance and good thermal shock resistance, and the preparation method has the characteristics of simple operation, no need of large-scale forming presses and low investment.)

1. The square crucible for casting molding is characterized by comprising the following raw materials in parts by weight: 10-30 parts of alumina powder, 5-20 parts of corundum powder, 15-20 parts of plate-shaped corundum with the diameter of 3mm-1mm, 10-20 parts of 20-mesh corundum particles, 5-20 parts of 36-mesh corundum particles, 5-10 parts of 80-mesh corundum particles, 10-20 parts of 180-mesh fused mullite and 5-10 parts of dispersing agent.

2. The square crucible of claim 1, wherein the square crucible further comprises the following raw materials in parts by weight: 0-15 parts of 400-mesh quartz fine powder and 0-5 parts of kaolin powder.

3. The square crucible of claim 2, wherein the square crucible comprises the following raw materials in parts by weight: 15 parts of alumina powder, 10 parts of corundum powder, 18 parts of 3mm-1mm tabular corundum, 13 parts of 20-mesh corundum particles, 10 parts of 36-mesh corundum particles, 8 parts of 80-mesh corundum particles, 15 parts of 180-mesh fused mullite, 6 parts of 400-mesh quartz fine powder and 5 parts of dispersing agent.

4. The cast square crucible of claim 1, wherein the dispersing agent is sodium tripolyphosphate.

5. A method for preparing a square crucible for casting molding, which is characterized by comprising the following steps:

1) iron removal: magnetic separation and iron removal are carried out on various raw materials by a strong magnetic separator;

2) stirring: weighing various raw materials according to a ratio, mixing the raw materials with water, stirring while vacuumizing for 20-40min to form slurry;

3) pouring: pouring the stirred slurry into a square crucible gypsum model;

4) demolding: after the gypsum model absorbs water for 3 to 6 hours, the slurry is completely hardened and demoulded;

5) drying: after demoulding, putting the mixture into a drying kiln for drying, and discharging water;

6) and (3) firing: and drying, then loading into a sintering kiln, and sintering at 1500-1600 ℃ to obtain the finished square crucible.

6. The method of claim 5, wherein the stirring in step 2) is performed by a vacuum stirrer.

7. The method of claim 5, wherein the amount of water used in step 2) is 6 to 10 parts.

8. The method of claim 5, wherein the step 3) is performed by vibration casting.

9. The method of claim 5, wherein the firing time of step 6) is 6 hours.

Technical Field

The invention relates to the technical field of refractory material products, in particular to a square crucible formed by casting and a preparation method thereof.

Background

The crucible is an important component of a chemical instrument, is a container for melting and refining metal liquid, heating solid and liquid and reacting, and is the basis for ensuring the smooth progress of chemical reaction. Corundum is more resistant to high temperatures than glassware, so when solids are to be heated by a strong fire, crucibles are often used as containers. According to different production raw materials, the crucible can be summarized into three types, namely crystalline natural graphite, plastic refractory clay and calcined hard kaolin skeleton clinker. In recent years, high temperature resistant synthetic materials have also come to be used, such as: silicon carbide, alumina emery, ferrosilicon and the like are used as framework clinker of the crucible.

The corundum crucible, which is usually a crucible with an alumina content of more than 95%, has the characteristics of high temperature resistance, hardness and melting resistance, but still has the defects of poor thermal shock resistance and corrosion resistance, and also has the defects of easy generation of cracks, easy peeling and easy product pollution in the use process.

Disclosure of Invention

The invention provides a casting square crucible and a preparation method thereof, aiming at the technical problems of poor thermal shock resistance stability, poor erosion resistance, easy generation of cracks, easy peeling and easy pollution of products of the existing corundum crucible.

In a first aspect, the invention provides a square crucible for casting molding, which comprises the following raw materials in parts by weight: 10-30 parts of alumina powder, 5-20 parts of corundum powder, 15-20 parts of plate-shaped corundum with the diameter of 3mm-1mm, 10-20 parts of 20-mesh corundum particles, 5-20 parts of 36-mesh corundum particles, 5-10 parts of 80-mesh corundum particles, 10-20 parts of 180-mesh fused mullite and 5-10 parts of dispersing agent.

Further, the square crucible also comprises the following raw materials in parts by weight: 0-15 parts of 400-mesh quartz fine powder and 0-5 parts of kaolin powder.

Further, the square crucible comprises the following raw materials in parts by weight: 15 parts of alumina powder, 10 parts of corundum powder, 18 parts of 3mm-1mm tabular corundum, 13 parts of 20-mesh corundum particles, 10 parts of 36-mesh corundum particles, 8 parts of 80-mesh corundum particles, 15 parts of 180-mesh fused mullite, 6 parts of 400-mesh quartz fine powder and 5 parts of dispersing agent.

Further, the dispersing agent is sodium tripolyphosphate.

In a second aspect, the present invention provides a method for preparing the above square crucible, the method comprising the steps of:

1) iron removal: magnetic separation and iron removal are carried out on various raw materials by a strong magnetic separator;

2) stirring: weighing various raw materials according to a ratio, mixing the raw materials with water, stirring while vacuumizing for 20-40min to form slurry;

3) pouring: pouring the stirred slurry into a square crucible gypsum model;

4) demolding: after the gypsum model absorbs water for 3 to 6 hours, the slurry is completely hardened and demoulded;

5) drying: after demoulding, putting the mixture into a drying kiln for drying, and discharging water;

6) and (3) firing: and drying, then loading into a sintering kiln, and sintering at 1500-1600 ℃ to obtain the finished square crucible.

Further, in the step 2), a vacuum stirrer is adopted for stirring.

Further, in the step 2), the using amount of water is 6-10 parts.

Further, the pouring of the step 3) adopts a vibration pouring mode. The vibration pouring can make the blank more compact, the porosity is lower, and the strength is higher.

Further, the firing time in the step 6) is 6 hours.

The beneficial effect of the invention is that,

the invention provides a square crucible for casting molding,

(1) the corundum with various different granularities is used as a raw material, so that the materials can be compactly stacked, the volume density is improved, and the strength is increased.

(2) The raw materials are added with the fused mullite, so that the fire resistance of the fused mullite is high and can reach 1750 ℃. Meanwhile, the crystal phase is mullite phase and has a rod-shaped structure, so that the thermal shock resistance is strong, and the thermal shock resistance is good.

(3) Adding quartz fine powder into the ingredients, and sintering the productIn-process SiO₂With Al₂O₃A mullite crystalline phase is formed in the matrix. The thermal shock resistance and the spalling resistance of the product are enhanced. The corundum phase in the product also has the characteristics of high temperature resistance and high strength.

(4) The square crucible has the characteristics of high temperature resistance, high strength, stripping resistance, erosion resistance and good thermal shock resistance. The product has a refractoriness of over 1750 ℃, fully meets the use requirements of 1600-1650 ℃, has a normal-temperature compressive strength of over 115MPa, and has thermal shock resistance of over 12 times of water cooling at 110 ℃.

The invention also provides a preparation method of the square crucible, which has the characteristics of simple operation, no need of large-scale forming press and low investment.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.