For manufacturing of glass, which among the following is used as a source of silica?

The correct answer is Sand.

Key Points

• The raw materials used in the manufacture of glass are sand, lime chalk, soda, or potash which are fused over 1000° C.
• The functions of the various ingredients are given below:
  • Lime: Lime is used in the form of limestone, and chalk.
    • The addition of lime makes glass fluid and suitable for blowing, drawing or rolling, pressing or spinning.
    • It also imparts durability and stiffness to the glass.
  • Silica: Silica is used in the form of pure quartz, crushed sandstone and pulverized flint.
    • It is added to lower the fusion temperature.
    • Silica sand is used as a primary source of silicon- dioxide and its proportion is 95% in the composition of silica.
  • Soda: Soda acts as an accelerator to the fusion of the glass and in excess of it is harmful.