High purity alumina (High Purity Alumina, HPA)As a key foundational material in fields such as electronics, optics, and ceramic materials, there are certain requirements for its purity and particle size distribution. According to its ultimate use, the purity usually needs to reach99.99%Above, even reaching5N (99.999%)Level. The widely used preparation methods in current industry includeChemical precipitation methodandsol-Gel method (Sol-Gel)In these two process flows, filtration, washing, and drying are key steps to ensure product purity, particle size controllability, and morphology integrity.

1、 Process background: Preparation of high-purity alumina by chemical precipitation method

In the chemical precipitation method, aluminum salts (such asAlCl₃TheAl(NO₃)₃Or aluminum isopropoxide) is used as a precursor, and precipitation reaction is carried out by adding ammonia water or carbonate to generateAl(OH) ₃Gel. Subsequently, it was thoroughly washed to removeCl⁻TheNO₃⁻Waiting for impurities ions, finally drying and calcining to obtainγ-Al₂O₃orα-Al₂O₃Powder. The purity of this method can reach99.99%Above, but the process flow is long and the operation is complex, requiring high requirements for equipment sealing and cleanliness.

2、 Technical advantages and integration points of three in one equipment

Our company independently develops and manufacturesThree in one filtration, washing, and drying equipment (Agitated Nutsche Filter Dryer, ANFD)It is designed for such complex and refined processes, and its application in the preparation of high-purity alumina is demonstratedSignificant advantages include:

1. Closed system to prevent impurities from contaminating again

The entire filtration, washing, and drying process is continuously completed in a sealed container, greatly reducing the risk of external environmental pollution to high-purity materials and meeting the requirements of electronic and optical gradeHPAThe need for cleanliness.

2. Precise washing to improve ion residue removal efficiency

The equipment is equipped with a bottom filter plate and a multi-directional stirring device, which can achieve dynamic washing of sediment and effectively remove itCl⁻TheNO₃⁻Wait for residual impurities to improve the electrical resistivity and transparency of the product.

3. Vacuum drying function to protect the integrity of material structure

After washing, it can be directly transferred to the vacuum drying stage to avoid losses or agglomeration caused by material transfer in traditional processes, while reducing the risk of structural damage of thermosensitive materials at high temperatures.

4. Automated control to improve batch stability

Three in one device supportPLCThe control system can achieve automatic control and recording of key parameters such as temperature, stirring speed, and pressure, ensuring process consistency between batchesHPAThe important equipment foundation for production automation and intelligence.

3、 Process application diagram (combined withSol-GelLaw)

InSol-GelIn the law, aluminum alkoxide and water/The alcohol solvent reacts to generate transparent sol, and then gel is converted into dry gel. The solvent residue and impurities are removed through filtration, and finally the nanometer high-purity alumina powder is obtained through drying and calcination. This method is suitable for preparing nano alumina with high specific surface area and special morphology.

The three in one device is used in this process to handle:

lLow shear filtration of gel

lRepeated washingwithRemove organic residues

lVacuum low-temperature dryingdrynesswithguaranteeProtective morphology structure

The synergistic improvement of particle size control, morphology control, and purity control has been achieved.

With the development of the materials industry, the market demand for high-purity alumina continues to grow. The traditional multi-step split process is no longer able to meet the comprehensive requirements of modern manufacturing for efficiency, quality, and cleanliness. Our company's three in one filtration, washing, and drying equipment, with its advantages of being sealed, safe, continuous, and automated, has been used in multiple locationsHPAThe successful application in production enterprises has become an important driving force for the upgrading of fine material preparation technology.