Glasses, alkali-iron-silicate

Belyustin and co-workers (4) have observed three-line spectra in their alkali (10-20% )-iron (1-15% )-silicate glasses with the same interpre-... 

Anhydrous alkali silicates with Si02/alkali oxide > 1.5 (solid glasses) are manufactured by reacting fine particulate quartz sand, which is as pure as possible, is clay-free and has a low iron content, with alkali carbonates or hydroxides at 1300 to 1500°C in tank furnaces lined with refractory bricks or in rotary tube... 

Alkali, alkaline earth, iron, and similar impurities that are present largely combine with the siliceous material to form a low-melting-point glass and decrease the refractoriness of the brick. 

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