Spherical alumina is produced by high-temperature melting, high spherical rates, and high alphaphase aluminum oxide content. This product has superior performance in rubber, plastic, and ceramic feedstock.
Here is a summary of the methods for preparing spherical-grade alumina. Each method has its own characteristics.
Here are seven ways to prepare spherical aluminum:
Various sedimentation method
The precipitation process in homogeneous solutions is a crystal nuclear reaction. After that, the aggregation becomes greater and eventually from the solution it is usually unbalanced. But, if you lower the concentration of precipitant in homogeneous, even slowly, then large numbers of microcrystals nuclei will be evenly produced. Finally, the finely precipitated particles can be uniformly distributed throughout the entire solution. This ensures that the equilibrium state is maintained over a prolonged period. Method for average prediction. Al2 (SO4)3, Al (NO3) 3 & urea are used as raw materials. Under the conditions of an oil bath 98°C, the hydroxide produced by slow hydrolysis of Urea is precipitated. The size of the precursor particle can be adjusted by adjusting the proportion of SO422- with NO3–. This allows for the preservation of the spherical structure after calcination. Al2 (SO4) 3. The obtained colloid particles have a very good shape. This method was used in Al2(SO4) 3 and Urea as raw materials. The spherical (and hollow spherical) alumina powders were prepared under different conditions. A homogeneous precipitation process is possible if the precipitated particles obtained fall within the range for colloid particles. In addition to the conditions of SO42 – present, it is often difficult to finally form a glue of the globiosis in the gelation of sol particles to finally form a globiotype, so people think that this formation of sol-emulsion-condensation Gladle.
2. Sol-emulsion-gel method
This method is based on the sol-gel method. To obtain spherical powder particles from the oil phase, one uses the interface tension of both the oil and the water phases to form small droplets. Aluminum hydrolysis produced the spheroidized powder of alumina. The aluminum hydrolysis process used acetonitrile as a solvent and octanol to dissolve aluminum for 50%. However, the acetonitrile solvent was 40%. The octanol, butanol, and dispersed waters for 9% and 1 percent respectively. Using hydroxypropylcellulose as a dispersant to obtain a spherical g-alumina powder having a very good spherical degree.
3. Drip method
Droplet methods are used to bind the alu sol to the oil layer. This is usually done using paraffin, mineral oils, etc. The resulting spherical sol particle is then gelled in an alkaline ammonia solution. This is used to further enhance the sol-emulsion gel method.
4. Use templates
The template method controls the morphology during the production of spherical foodstock. The product is often hollow or has a nuclear-shell structure. The aluminum powder surface is used for simplifying the aluminum powder’s surface. While the template method can be used to prepare an air spherical ball sphere, it has limitations. The preparation steps are more involved and require more effort.
5. Gas solve decomposition method
Aerosol decomposition uses aluminum salts as a raw material. It makes use of the properties of aluminum alcohol and high-temperaturepyrolysis. Next, it uses phase transition to gasify aluminum oxide, then contact with hydrogen vapor. Finally, it picks up high temperatures dry or direct high temperatures, thereby achieving transitions of gas-liquid solid or gas-solid phase and finally, creating a spherical form of alumina powder. Complex experiments involving reaction moieties as well as atomizing moiety are key to this method.
6. Radio frequency induction plasma method
Radio frequency plasma treatment of alumina dust using radio frequency radiation. This plasma has high energy density and high heating power. It also allows for simple material processing. The powder is free from any electrodes and therefore not contaminated by electrode evaporation. It is possible for purity to be maintained. Additionally, irregular shaped alumina particles can be sprayed into plasma torch with the feed gas. Plasma melts rapidly and is quickly heated. Droplets will quickly solidify, creating spherical particle.
The essence and structure of spinal alumina are formed quickly by surface tension. You can divide it into spray heat, spray drying, and spray melting Law, depending on the characteristics of phase transformation. AlCl3, Al2 SO4) 3, Al (NO3) 3 solution form small droplets through atomization. The process also requires a high thermal decomposition temperature of around 900°C. First, react the aluminum salt solution to ammonia to make an alumina sol. Next, spray the sol at 150 to 240 deg C.
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