Magnesium oxide light

Alagnesium Oxide. Magnesia [1309-48 ] MgO, is available in a very bulky white powder known as light magnesium oxide, or a relatively dense white powder known as heavy magnesium oxide. It absorbs moisture and carbon dioxide when exposed to air. It is practically insoluble in water, insoluble in alcohol, and soluble in dilute acids (see Magnesium compounds). 

Examples Magnesium Carbonate, Light Magnesium Oxide, Calcium Hydroxide, Chalk, KOH, NaOH. 

Buffer solution, double strength - add to 4.5 I water, 400 g oven-dried calcium acetate, 80 g 4-nitrophenol and 6 g of light magnesium oxide. [Safety note 4- (or para-) nitrophenol may cause eye irritation or irreversible eye injury, and may be harmful by absorption through skin or ingestion.] Heat the mixture to dissolve the solids and dilute to 5 I. Filter if the solution is not clear. The pH of this solution should lie between 6.9 and 7.1 adjust by the addition of hydrochloric acid or magnesium oxide as necessary. 

Labeling Indicate whether it is Light Magnesium Oxide or Heavy Magnesium Oxide. 

BP Heavy magnesium oxide and Light magnesium oxide JP Magnesium oxide... 

Particle size distribution 99.98% less than 45 pm in size (light magnesium oxide). 

Figure 6.20 Adsorption of digoxin by some antacids at 37 0.1°C ( ) magnesium trisilicate, (A) aluminium hydroxide gel BP (Aludrox was used in the concentration range 2.5-10%v/v), (A) light magnesium oxide, (O) light magnesium carbonate, ( ) calcium carbonate. Initial concentration of the glycoside 0.25 mg%.

To 1 to 1 5 g of syrup in a covered platinum dish add 0 5 g of light magnesium oxide, take to dryness on a water-bath and carefully ignite. Heat the white ash obtained for thirty minutes in the presence of 5 per cent nitric acid to ensure the whole of the phosphate being present as orthophosphate. Proceed by the method given on p. 530, but using 15 g of ammonium nitrate in precipitation and allowing the precipitated phosphomolybdate to stand for one hour before filtration. 

Light or heavy magnesium carbonate is exposed to a red heat, and carbon dioxide and water are expelled leaving light or heavy magnesium oxide. The density is also influenced by the calcining temperature higher temperatures yield more compact forms. 

Magnesium oxide is an effective nonsystemic antacid, ie, it is converted to the hydroxide. It does not neutralize gastric acid excessively nor does it hberate carbon dioxide. The light form is preferable to the heavy for adininistration in Hquids because it is suspended more readily. One gram of magnesium oxide neutralizes 87 mL of 0.1 NUCl in 10 min, and 305 mL in 2 h. 

AH latex compounds should contain at least 5 phr of zinc oxide. This is needed to absorb evolved hydrochloric acid either in the compound or finished part. A larger amount should be considered if the part contains or is in contact with acid-sensitive materials such as cotton cloth. Magnesium oxide may destabilize anionic soap systems, and is avoided for that reason. The compound should also contain two parts of an antioxidant, and consideration should be given to the need for a uv screen in light-colored products. 

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