What Is Magnesite?
Magnesite, primarily composed of magnesium carbonate, is a mineral. Although mainly magnesium carbonate, it occasionally contains trace amounts of iron, manganese, cobalt, and nickel. The iron-containing varieties are called breunelite.
Uses of Magnesite
1. Raw Material for Magnesium Oxide
Magnesite is predominantly used to produce magnesium oxide through heat treatment. Known as light-burned magnesite, this material is an essential refractory used for lining blast furnaces, kilns, and incinerators, thanks to its excellent heat storage properties. It also serves as a heat storage core in nighttime storage heaters and electric fireplaces. As a soil hardener, light-burned magnesite reacts with water, transitioning through magnesium hydroxide to form magnesium carbonate, a hardening agent, making it an environmentally friendly choice for agricultural applications.
2. Works of Art
Magnesite serves as a raw material for beads and various objects, prized for its ease of dyeing. It can be used as a substitute for turquoise or lapis lazuli or transformed into diverse ornaments through cutting, drilling, and polishing.
3. Other Uses
Additionally, magnesite acts as a binder in flooring materials (magnesite screed), a catalyst and filler in synthetic rubber manufacturing, and as a base material in systems designed to remove sulfur dioxide from industrial flue gases.
Properties of Magnesite
Magnesite is characterized by a rhombohedral or trigonal crystal structure, with a Mohs hardness of 3.5 to 4.5. It is transparent to white and displays a glassy luster. When exposed to ultraviolet light, it emits green or blue fluorescent and phosphorescent light. Calcining magnesite at around 1,000ºC leads to the desorption of carbon dioxide from magnesium carbonate, yielding magnesium oxide (MgO). The chemical formula for magnesium carbonate is MgCO3, with a molecular weight of 84.31. The anhydrate has a CAS number of 546-93-0 and is a white solid that decomposes at 350°C with a density of 2.958 g/cm3, exhibiting an odorless, tasteless, triangular crystal structure.
Other Information on Magnesite
1. How Magnesite Is Produced
China is a major producer of magnesite. Magnesite can also be synthesized artificially by carbonating magnesium serpentinite, resulting in magnesium carbonate trihydrate (nesquihonite).
2. Handling and Storage Precautions
Magnesium carbonate requires careful handling. Wear protective glasses with side shields, long-sleeved protective clothing, and gloves. Ensure use within a local exhaust ventilation system. In the event of a fire, choose an extinguishing method suitable for the site and environmental conditions. For storage, keep in a cool, well-ventilated space, in sealed polyethylene containers, away from direct sunlight, and ensure the storage area is securely locked.