The three main constituents of glass are sand, soda, and what else?
Soda–lime glass thermal shock, being able to survive immersion in water while red hot, its high melting temperature (1723 °C) and viscosity make it difficult to work with. Other substances are therefore added to simplify processing. One is the "soda", or sodium carbonate (NaCO), which lowers the glass-transition temperature. However, the soda makes the glass water-soluble, which is usually undesirable. To provide for better chemical durability, the "lime" is also added. This is calcium oxide (CaO), generally obtained from limestone. In addition, magnesium oxide (MgO) and alumina, which is aluminium oxide (AlO), contribute to the durability. The resulting glass contains about 70
Soda–lime glass to 74% silica by weight. The manufacturing process for soda–lime glass consists in melting the raw materials, which are the silica, soda, lime (in the form of (Ca(OH)), dolomite (CaMg(CO), which provides the magnesium oxide), and aluminium oxide; along with small quantities of fining agents (e.g., sodium sulfate (NaSO), sodium chloride (NaCl), etc.) in a glass furnace at temperatures locally up to 1675 °C. The temperature is only limited by the quality of the furnace structure material and by the glass composition. Relatively inexpensive minerals such as trona, sand, and feldspar are usually used instead of pure chemicals. Green and