Тригидрат карбоната магния

Description

Magnesium carbonate trihydrate MgCO3·3H2O is a crystalline hydrate of magnesium carbonate with three molecules of water of crystallization; in the card the formula is written in gross form CH6MgO6. A natural analogue is the mineral nesquegonite. The commercial product is obtained by carbonation of a suspension of magnesium oxide or hydroxide with carbon dioxide at moderate temperatures: under these conditions, it is the trihydrate, and not the anhydrous salt, that crystallizes from the solution. Belongs to the class of inorganic salts, subsection - carbonates of alkaline earth metals.

Basic Attributes

• CAS No.: 5145-46-0
• Chemical formula: CH6MgO6 (MgCO3 3H2O)
• Molecular weight: 138.358
• Exact weight: 138.001
• DSSTox ID: DTXSID60199429
• PSA specifications: 66.2
• XLogP3: −2.63990
• Boiling point: 333.6 °C at 760 mmHg. Art. (supplier card value)
• Flash point: 169.8°C (supplier card value)
• Appearance: white powder or colorless needle-shaped crystals
• Density of natural nesquegonite: 1.85 g/cm³
• Mohs hardness (nesquik drive): 2.5

Behavior when heated and in water

The salt is slightly soluble in water; it dissolves in dilute acids, releasing carbon dioxide. When heated, it successively splits off the water of crystallization and turns into basic magnesium carbonates, then into magnesium oxide. The trihydrate is thermodynamically metastable: when stored in a humid environment, it gradually turns into hydromagnesite. To stabilize commercial batches, phosphate buffer treatment is used at pH 7 - magnesium phosphate is formed on the surface of the crystals, which inhibits recrystallization.

Scope of application

• carbon dioxide mineralization (CCUS): trihydrate formation is kinetically favorable at ordinary temperature and atmospheric pressure, CO2:MgO ratio is the highest among hydrated magnesium carbonates
• binders and prefabricated building elements on a carbonate basis: the compressive strength of the resulting compositions reaches 8 MPa, thermal conductivity 0.21–0.33 W/(m K), which provides materials with thermal insulation properties
• raw materials for producing magnesium oxide and anhydrous magnesium carbonate by calcination
• filler and fire retardant additive in polymer compositions: upon decomposition, releases water and CO2, diluting flammable gases
• laboratory reagent in studies of crystallization of magnesium carbonates

Storage and transportation

Store in a tightly closed container in a cool, dry place. Moisture and elevated temperature accelerate the transition to other hydrate forms, so opened packages should be closed immediately after collection. The card does not contain transport restrictions by hazard class.