Soda-alumina-silica

The phase structure of glasses has a significant effect on their physical properties, which is discussed below with reference to chemical durability. The magnitude of the phase separation can be altered by heat treatment, and enhanced or reduced by the addition of various oxides to the melt. In particular, the addition of alumina to commercial soda-lime-silica glasses reduces the tendency to phase separation, improving chemical resistance (Doremus, 1973). A detailed study of the microstructure of soda-lime-silica glasses has been published by Burnett and Douglas (1970). The control of phase separation in the melt is now commercially important for processes such as the... 

The sodium chloride and sulphate regularly found in Leblanc soda ash are not usually injurious the insoluble matter should not exceed 1 to 1J per cent. It consists principally of calcium carbonate, alumina, silica, and ferric oxide. The sulphides should not be detectable by lead paper thiosulphates are destroyed in calcining the ash sulphites are usually present and can be detected by iodine soln. and sodium hydroxide, except in the so-called caustic ash, does not usually exceed 1 per cent. The moisture in fresh ash ranges below one per cent. Owing to the mode of preparation, ash by Solvay s process is more pure than that prepared by Leblanc s process. It does not contain sodium hydroxide, sulphides, sulphites, or thiosulphates it may contain a slight excess of carbon dioxide a little sodium sulphate is always present iron, alumina, and silica are present in minute traces sodium chloride is perhaps the only... 

The production of zeolites is frequently performed in batch reactors. Gel precipitation and crystallization are then carried out stepwise. A sodium aluminate solution is prepared first by mixing an alumina source with caustic soda. The silica-containing solution is then dosed to the alkaline alumina-containing solution [140]. 

Borosilicate glass contains about 80% silica, 13% boric oxide, 4% alkali, and 2% alumina. It is more heat-shock-resistant than most glasses due to its unusually small coefficient of thermal expansion (typically between 2 and 5 x 10 cm /°C for soda-lime glass it is 8 to 9 X 10 cm /°C). It is better known by such trade names as Kim ax and Pyrex. Bakeware and glass pipelines are often borosilicate glass. 

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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