Magnesium orthosilicate

Forstente. Pure forsterite is rare in nature. Most natural magnesium orthosilicates form solid solutions of fayalite, Fe2Si04, and forsterite. Forsterite refractories are usually made by calcining magnesium silicate rock such as dunite, serpentine, or olivine with sufficient magnesia added to convert all excess silica to forsterite and all sesquioxides to magnesia spinels. 

A special group of inhibitors are those substances which suppress the decomposition of hydrogen peroxide in alkaline solutions, which are used for bleaching purposes or for preparation of addition compounds of hydrogen peroxide. Good stabilizers for such solutions are e. g. magnesium orthosilicate, water glass and phosphates of alkaline-earth metals. 

Magnesium aluminum silicate magnesium metasilicate magnesium orthosilicate magnesium trisilicate talc. 

Comments magnesium orthosilicate (Mg2Si04) occurs in nature as the mineral forsterite. 

Magnesium orthosilicate, Mg204Si. Occurs in nature as the mineral jorsterite. White orthorhombic crystals, mp 1910° d 3.21. Practically insol in water. 

Li20[g] LITHIUM OXIDE (GAS) 973 Mg2Si04 MAGNESIUM ORTHOSILICATE 1019... 

The magnesium silicates are obtained from natural sources, such as talc (magnesium silicate hydroxide), ensta-tite (magnesium metasilicate), forsterite (magnesium orthosilicate), meerschaum (magnesium trisilicate), or serpentine (Mg3Si207). In all cases, extraction of the desired compound... 

The various methods of preparing monosilicic acid may be summarized as follows. A saturated solution of monosilicic acid, SifOH), containing about 0.01% SiOj, is obtained when pure amorphous silica is equilibrated with water at room temperature. A more concentrated (supersaturated) solution can be obtained only indirectly by liberating monosilicic acid from its compounds under carefully controlled conditions at low temperature and low pH, dilute solutions remain supersaturated with respect to amorphous silica for appreciable periods. For example, at pH 3 and 0°C, solutions of monosilicic acid up to O.l (0.6% SiOj) can be prepared by spontaneous hydrolysis of monomeric silicon compounds, sich as silicon tetrachloride or methyl orthosilicate, and also by reacting monomeric silicates, such as sodium or magnesium orthosilicates or hydrated crystalline sodium metasilicate, with dilute acid. 

Monomeric crystalline silicates dissolve and are neutralized to liberate monosilicic acid at about pH 2. Kraut (23) prepared monosilicic acid by dissolving sodium meta-silicate hexahydrate in various acidic solutions at low temperature. He reported that monosilicic acid is most stable at around pH 2-3. Weitz, Franck, and Schuchard (20) demonstrated that when Na2Si03-9Hj0 was reacted with acetic acid it liberated Si(OH)4. Also olivine (magnesium orthosilicate, Mg-SiOO dissolved in 1.0 N HCl to give a practically 100% yield of monosilicic acid, the solution containing 0.04% SiO,. Thus monosilicic acid may be liberated from silicates which contain SiO ions separated by cations, such as are present in anhydrous orthosilicates. 

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