Definition of fused quartz and silica

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fused quartz and silica: Fused quartz and silica are closely related materials, both composed primarily of silicon dioxide (SiO₂), but they are produced through different manufacturing processes and have distinct properties and applications.

Fused Quartz:

Manufacturing process: Fused quartz is produced by melting high-purity silica sand or quartz crystals at extremely high temperatures (over 1,700 ºC) and then cooling it rapidly to form a non-crystalline, vitreous solid.

Purity: Fused quartz typically has very high purity levels, with minimal impurities that could affect its optical or mechanical properties. It is often used in applications requiring high transparency and optical clarity.

Properties:

High thermal stability: Fused quartz exhibits excellent thermal stability and can withstand high temperatures without softening or deforming, making it suitable for use in high-temperature applications such as furnace tubes, crucibles, and semiconductor manufacturing.

Low thermal expansion: Fused quartz has a low coefficient of thermal expansion, meaning it experiences minimal dimensional changes with temperature fluctuations.

High transmission in the UV and visible range: Fused quartz has exceptional optical transparency, particularly in the UV and visible wavelength ranges, making it ideal for optical components such as lenses, windows, and prisms used in UV spectroscopy, laser systems, and photolithography.

Silica:

Natural form: Silica is a naturally occurring compound found in various forms, including quartz, sand, and glass. Quartz, a crystalline form of silica, is one of the most common minerals on Earth's crust.

Manufactured silica products: Silica can also be produced synthetically through various manufacturing processes. For example, amorphous silica (also known as fused silica) is produced by melting and rapidly cooling silica sand or silicon dioxide powder, similar to the process used to make fused quartz.

Properties:

Versatility: Silica exhibits a wide range of properties depending on its form and manufacturing process. It can be found in crystalline forms such as quartz, as well as amorphous forms such as fused silica and silica gel.

High melting point: Silica has a high melting point, making it suitable for applications requiring heat resistance, such as refractories and ceramics.

Chemical inertness: Silica is chemically inert and resistant to most acids, bases, and solvents, making it suitable for use in chemical processing, filtration, and purification applications.

Absorption of moisture: Silica can absorb and desorb moisture from the atmosphere, making it useful as a desiccant in applications such as humidity control and moisture removal.

In summary, fused quartz is a specific type of silica glass produced through a high-temperature melting process, prized for its high purity, optical transparency, and thermal stability. Silica, on the other hand, refers more broadly to silicon dioxide in various forms, including both natural minerals like quartz and manufactured products like fused silica. Both materials have diverse applications across industries, ranging from optics and electronics to manufacturing and construction.