Silicon dioxide (SiO ₂) is a compound widely present in nature, with various forms and uses. It can be generated in several different ways, mainly including natural processes and industrial synthesis.
The production of silica in natural processes:
Volcanic activity: Silicon dioxide is one of the most common minerals in the Earth's crust, mainly existing in the form of minerals such as quartz and feldspar. When a volcano erupts, the magma contains a large amount of silicon dioxide. When the magma cools, the silicon dioxide crystallizes in the form of quartz mineral.
Weathering process: Carbon dioxide in the atmosphere reacts with water to form minerals such as calcium carbonate. When these minerals are exposed to the air, they react with moisture through weathering, ultimately forming silica deposits. Weathering is an important way for silica to be generated in nature.
Marine biota: Diatoms and other marine organisms in the ocean absorb silicon elements from seawater to synthesize silica shells (known as silica shells). The remains of these organisms deposit on the seabed, eventually forming minerals containing silica such as diatomaceous earth.
Silicon dioxide production during industrial synthesis process:
Purification of silica sand: In industrial production, silica is mainly obtained through the purification of natural silica sand (such as quartz sand). The silica content in silica sand is usually high, and pure silica is obtained through a series of washing, heating, and chemical treatments to remove impurities.
Reduction reaction of silicon: At high temperatures, silica (SiO ₂) reacts with carbon to produce metallic silicon and carbon dioxide. This process usually occurs in smelting furnaces, but also releases a certain amount of silica gas. Through appropriate cooling, these gases will eventually form silica particles.
Vapor deposition method: When producing high-purity silicon dioxide, vapor deposition, such as low-pressure chemical vapor deposition (LPCVD) technology, is commonly used. This method generates silicon gas by reacting in the gas phase, and after cooling, deposits a silicon dioxide film on the substrate surface, which is widely used in electronic devices, solar cells, and other fields.
Changes and forms of silica:
Crystalline state: In nature, silicon dioxide exists in a crystalline state, with quartz being the most common form. Quartz has a hexagonal crystal structure and is very stable, with high hardness and wear resistance.
Amorphous (silica gel): In industry, amorphous silica gel can be produced by reacting hydrated sodium silicate with acid. Silicone is usually in the form of amorphous powder or particles and is widely used in fields such as desiccants, catalyst carriers, and water treatment.
In summary, the production of silicon dioxide involves both natural processes such as volcanic activity and biological processes, as well as industrial synthesis methods. The form and use of silicon dioxide also vary in different processes. It is a very important chemical substance with wide applications in various fields such as construction, electronics, chemistry, and environmental protection.