Preparation method of molten aluminum filtering material

Abstract

The invention discloses a preparation method of a molten aluminum filtering material, which comprises the following steps of: firstly, dispersing and mixing the materials by using a ball milling process by taking brown aluminum oxide and aluminum in a certain proportion as main raw materials and a certain amount of plasticizer, binding agent and water as auxiliary materials, and finally, ramming and forming to process the materials into a required shape. And keeping the temperature at 1200 DEG C for 1 hour, pre-sintering at high temperature, and then starting to use. The defect that an aluminum liquid filtering material contains many impurities is overcome, the purity of the aluminum liquid is greatly improved, and the aluminum liquid filtering material can be better applied to the field of materials.

Description

Technical Field

[0001] The invention belongs to the technical field of refractory materials, and particularly relates to a method for preparing a molten aluminum filter material. Background Art

[0002] Aluminum is a silvery-white metal with a low density, only about 1 / 3 of the common metals iron and copper. It is also called light metal and is often used in the manufacture of land, sea and air transportation vehicles such as automobiles, trains, subways, ships, airplanes, rockets, and spacecraft. In order to reduce the weight and increase the load capacity, the requirements for the intrinsic quality of aluminum are getting higher and higher; metallurgical defects in aluminum, such as inclusions, hydrogen, and impurity elements, will directly affect its mechanical properties and processability; aluminum liquid treatment is the main way to improve the metallurgical quality of aluminum, among which purification treatment is its key technology; the higher the purity of aluminum liquid, the better the quality of aluminum processed later, but the current purification materials have a complex composition and a high impurity content, and the overall purification effect is poor. The purity of aluminum liquid after purification often does not meet expectations.

[0003] At present, most purification methods are to pour the liquid directly onto the filter, allowing the aluminum liquid to pass through the filter to filter out impurities in the aluminum liquid; this method is simple and practical, but it has very high requirements on the material of the filter, which must be both efficient and have good filtering effect. Summary of the invention

[0004] In order to improve the purity of aluminum materials, stabilize their quality, reduce the use steps of filter materials and reduce costs, the present invention provides a method for preparing aluminum liquid filter materials. The filter materials prepared by the method are convenient and durable, have negligible impact on the environment, and are suitable for industrial production.

[0005] The present invention adopts the following technical solutions to achieve the above-mentioned purpose: A method for preparing aluminum liquid filter material: characterized in that the preparation method specifically comprises the following steps: 1) Aluminum treatment: Mix 75% by mass of alumina powder and 25% of metal aluminum powder, and grind them together in a vibration mill to make the particle size d50 < 2μm; 2) Preparation of green body material: 81-84% brown corundum, 6-8% aluminum, 7-9% polyaluminum oxalate and 2-3% polyaluminum citrate are mixed, 5-6% water is added, stirred in a wheel mill for 10-15 minutes, and then rammed into shape according to the requirements of the filter screen, processed and trimmed, and dried at 150°C for 10-15 hours; the aluminum is the aluminum prepared in step 1); the polyaluminum oxalate and polyaluminum citrate act as plasticizers and binders at room temperature, and the holes left after high-temperature sintering absorb impurities, and the residual carbon can reduce part of the aluminum oxide, purify the aluminum liquid, and improve the purity of the aluminum material; 3) Assembly: sinter the blank material at 1200℃ for 1 hour, then cool, install and apply.

[0006] The polymerized aluminum oxalate and polymerized aluminum citrate function as plasticizers and binders at room temperature. The holes left after high-temperature sintering can absorb impurities, and the residual carbon can reduce part of the aluminum oxide, purify the aluminum liquid, and improve the purity of the aluminum material.

[0007] The invention proposes a method for preparing an aluminum liquid filter material, which adopts the fir tree technical solution. The prepared aluminum liquid filter material can be made into a multi-layer material according to the requirements of the filter net, thereby ensuring the filtering effect of the aluminum liquid. Since it does not contain other harmful components, it can be disassembled, replaced and cleaned at any time during use, thereby ensuring the efficiency and cleanliness of the aluminum liquid filtration. DETAILED DESCRIPTION

[0008] In order to fully illustrate the characteristics of the present invention, taking Examples 1 and 2 as examples, compared with Comparative Example 1 in which boric acid and cement are added as sintering aids, Comparative Example 2 in which boric acid and silica powder are added as sintering aids, and Comparative Example 3 in which boric acid and nano-calcium carbonate are added as sintering aids, the specific technical scheme of the present invention is further described. Embodiment 1:

[0009] A molten aluminum filter material and a preparation method thereof, comprising the following steps: (1) Aluminum treatment: Mix 75% by mass of alumina powder and 25% of metallic aluminum powder, and grind them in a vibration mill until the particle size d50 is less than 2 μm; (2) Preparation of green body material: 84% brown corundum, 6% aluminum, 8% polyaluminum oxalate and 2% polyaluminum citrate were mixed, and 5% water was added. The mixture was stirred in a wheel mill for 10 minutes, and then rammed into shape according to the requirements of the filter screen. Finally, the mixture was processed and shaped, and dried at 150°C for 10 hours. (3) Assembly: sinter the blank material at 1200℃ for 1 hour, then cool, install and apply. Embodiment 2:

[0010] A molten aluminum filter material and a preparation method thereof, comprising the following steps: (1) Aluminum treatment: Mix 75% by mass of alumina powder and 25% of metallic aluminum powder, and grind them in a vibration mill until the particle size d50 is less than 2 μm; (2) Preparation of green body material: 81% brown corundum, 7% aluminum, 9% polyaluminum oxalate and 3% polyaluminum citrate were mixed, and 6% water was added. The mixture was stirred in a wheel mill for 15 minutes, and then rammed into shape according to the requirements of the filter screen. Finally, the mixture was processed and shaped, and dried at 150°C for 15 hours. (3) Assembly: sinter the blank material at 1200℃ for 1 hour, then cool, install and apply.

[0011] Comparative Example 1: A molten aluminum filter material and a preparation method thereof, comprising the following steps: (1) Preparation of green body material: 88% brown corundum, 7% boric acid, 0.2% organic plasticizer, 2.8% cement, and 2% yellow dextrin were mixed, and 4% water was added. The mixture was stirred in a wheel mill for 15 to 20 minutes, and then rammed into shape according to the requirements of the filter screen. Finally, the mixture was processed and shaped, and dried at 110°C for 20 to 24 hours. (2) Assembly: Sinter the blank material at 1200℃ for 5 to 8 hours, then cool, install and apply.

[0012] Comparative Example 2: A molten aluminum filter material and a preparation method thereof, comprising the following steps: (1) Preparation of green body material: 88% brown corundum, 7% boric acid, 0.2% organic plasticizer, 2.8% silica powder, and 2% yellow dextrin were mixed, and 4% water was added. The mixture was stirred in a wheel mill for 15 to 20 minutes, and then rammed into shape according to the requirements of the filter screen. Finally, the mixture was processed and shaped, and dried at 110°C for 20 to 24 hours. (2) Assembly: Sinter the blank material at 1200℃ for 5 to 8 hours, then cool, install and apply.

[0013] Comparative Example 3: A molten aluminum filter material and a preparation method thereof, comprising the following steps: (1) Preparation of green body material: 88% brown corundum, 7% boric acid, 0.2% organic plasticizer, 2.8% nano calcium carbonate, and 2% yellow dextrin were mixed, and 4% water was added. The mixture was stirred in a wheel mill for 15 to 20 minutes, and then rammed into shape according to the requirements of the filter screen. Finally, the mixture was processed and shaped, and dried at 110°C for 20 to 24 hours. (2) Assembly: Sinter the blank material at 1200℃ for 5 to 8 hours, then cool, install and apply.

[0014] Compared with Comparative Examples 1, 2, and 3, the low-melting phase of the aluminum liquid filter material in Examples 1 and 2 is reduced. As the temperature rises, the aluminum powder wrapped with alumina powder adheres to the surface of brown corundum, forming a strong bonding strength. As the aluminum liquid is filtered, the holes and carbon remaining after the volatilization of polyaluminum oxalate and polycitric acid can well adsorb impurities and reduce alumina. However, the boric acid in the comparative example easily remains in the aluminum liquid, which is not conducive to the purification of the aluminum liquid. In addition, the impurities in the aluminum liquid easily form nodules with the boric acid, which seriously affects the filtering process of the aluminum liquid.

Claims

1. A method for preparing aluminum liquid filter material: characterized in that: The preparation method specifically comprises the following steps: 1) Aluminum treatment: Mix 75% by mass of alumina powder and 25% of metal aluminum powder, and grind them together in a vibration mill to make the particle size d50 < 2μm; 2) Preparation of green body material: 81-84% brown corundum, 6-8% aluminum, 7-9% polyaluminum oxalate and 2-3% polyaluminum citrate are mixed, 5-6% water is added, stirred in a wheel mill for 10-15 minutes, and then rammed into shape according to the requirements of the filter screen, processed and trimmed, and dried at 150°C for 10-15 hours; the aluminum is the aluminum prepared in step 1); the polyaluminum oxalate and polyaluminum citrate act as plasticizers and binders at room temperature, and the holes left after high-temperature sintering absorb impurities, and the residual carbon can reduce part of the aluminum oxide, purify the aluminum liquid, and improve the purity of the aluminum material; 3) Assembly: sinter the blank material at 1200℃ for 1 hour, then cool, install and apply.