Natural magnesia

The product obtained is called caustic-calcined magnesia (CCM), also called natural magnesia. The purity of CCM ranges usually between 75 and 96 wt.% MgO, with most of the impurities (e.g., Fe 03, AI3O3, SiOj, etc.) coming from the raw material used. 

Prices (2006). Prices are roughly 200 US /tonne for natural magnesia and up to 400 US / tonne for synthetic magnesia. 

Magnetic - from a place called Magnesia where magnetic iron oxide (Magnetite) occurred naturally. 

Forsterite. Pure forsterite is rare in nature. Most natural magnesium orthosiUcates form soHd solutions of fayaUte, Fe2Si04, and forsterite. Forsterite refractories are usually made by calcining magnesium siUcate rock such as dunite, serpentine, or oHvine with sufficient magnesia added to convert all excess siUca to forsterite and all sesquioxides to magnesia spinels. 

Purification. Alumina, AI2O3, is produced by the Bayer process (1,9) (see Aluminum COMPOUNDS) which involves digestion foUowed by precipitation and calcination. High purity magnesia is extracted from natural brines and seawater by precipitation and calcination (1,9). 

High 50,000 0,000 8-16 Aluminum, copper, zinc, vanadium, calcined dolomite, hme, magnesia, magnesium carhonates, sodium chloride, sodium and potassium compounds Flue dust, natural and reduced iron ores Flue dust, iron oxide, natural and reduced iron ores, scrap metals... 

Cbrome bricks are manufactured in much the same way as magnesite bricks but are made from natural chromite ore. Commercial ores always contain magnesia and alumina. Unburned hydraulically pressed chrome bricks are also available. 

Porous natural clays, alumina, magnesia, activated carbon, silica, asbestos... 

A variety of material could be used as the basis for cracking catalyst, including synthetic silica-alumina, natural clay, or silica-magnesia. If these materials did not contain significant amounts of metals such as chromium or platinum that catalyzed the burning of carbon, the burning rate of the coke is independent of the base as shown in Fig. 7. 

Often, the manganese ores contain several other naturally occurring metal oxides such as alumina, sihca, magnesia, and lime. Some of these oxides may be blended into manganese ore as fluxes to the furnace charge. 

But [said he] it was still necessary to learn the base of the salt. Its solution could not be precipitated either by tartaric acid in excess or by platinum chloride. Consequently it could not be potassium. I mixed another portion of a solution of the same salt with a few drops of pure potash, but without its becoming cloudy. Therefore it contained no more magnesia hence it must be a salt with soda for a base. I calculated the quantity of soda which would be necessary to form it but it always resulted in an excess of about 5 parts in 100 of the mineral analyzed. Therefore, since it seemed probable to me that the different substances might not have been well washed, Or that the analysis might not have been made with sufficient precision in other respects, I repeated it twice more with all the care possible, but always with results very little different. I obtained. Silica. 78 45, 79.85, Alumina 17 20, 17.30 Sulfate 19.50, 17.75. At last, having studied this sulfate more closely, I soon found that it contained a definite fixed alkali, whose nature had not previously been known (21). 

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