Distribution earth's crust and Manufacture of Sodium Metal

Distribution of sodium earth's crust

Sodium is a very abundant element on Earth and is widely distributed in various natural sources. It is the 6th most abundant element in the Earth's crust, constituting about 2.6% of its composition by weight.

Elemental sodium is found mainly as sodium chloride (table salt) in seawater and saltwater lakes. Sodium chloride can be obtained directly by evaporating seawater or lake water. Sodium is also found in various ores in the Earth's crust. The most common ore containing sodium is halite (NaCl), also known as rock salt. There are some other ores that contain sodium carbonate (Na₂CO₃), sodium nitrate (NaNO₃), and various silicates.

Sodium can also be found in soil, although its concentration can vary depending on the location and geological conditions. In some regions, soil may have high sodium content, leading to saline or alkaline soils, which can affect plant growth.

How is the pure sodium produced?

Sodium is strong reductive and difficult to be extracted by another reducing agents. In industry, sodium is extracted by electrolyzing liquid sodium chloride (NaCl). The anode of the electrolytic cell is made of carbon, while the cathode is made of iron. This process involves the electrolysis of molten sodium chloride (NaCl), which is achieved by heating the solid salt to a high temperature, until it melts and becomes a liquid. This molten sodium chloride solution can now conduct electricity, a crucial requirement for electrolysis. Some calcium chloride is usually added to lower the melting point of sodium chloride, allowing it to melt at around 500°C.

Sodium ions gather at the cathode, where they gain electrons to become metallic sodium. As sodium have a lower density than liquid sodium chloride, it floats on the surface of the electrolytic cell. Chlorine ions gather at the anode, where they lose electrons to become chlorine gas which is collected as a byproduct.

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