Explain the preparation method of spherical silica fume

he preparation method of spherical silica fume is described as follows:

Hydrolysis method and sol-gel followed by sintering method: Both of these methods are chemical wet processes. The sphericity of spherical silica fume produced by chemical methods and the radioactivity index can be extremely low. However, due to its low bulk density, when epoxy resin plastic packaging materials are entirely made of this spherical powder, the compactness, strength, and linear expansion rate of the plastic packaging block will be affected. Therefore, the actual increase in practical applications can only reach 40%.

The melting method using a high-temperature plasma field as the heat source can achieve temperatures exceeding five times those of chemical combustion (above 3000K). The high temperature, intense heat, and highly reactive atmosphere accelerate chemical reactions, leading to the rapid formation of high-temperature phase compounds (such as nitrides, carbides, and borides), which are difficult to synthesize via chemical liquid-phase methods. When reactants exit the plasma, the cooling rate is extremely high (–105K/s), preventing further particle growth. Depending on specific needs, different plasma states can be formed under varying atmospheres. With a broad range of reactants (gases, solids, and liquids), this method facilitates plasma spheroidization research. Ho