Question

Arrange the steps involved in the manufacture of glass in a correct sequence.

• A. Preparing batch
• B. Melting
• C. Moulding
• D. Annealing

Answer 1

During the manufacturing of glass:

• Sand $\left({\mathrm{SiO}}_2\right)$, soda ash $\left({\mathrm{Na}}_2{\mathrm{CO}}_3\right)$ and calcium carbonate $\left({\mathrm{CaCO}}_3\right)$ are mixed in the first step. There mixture is called a 'batch'. Small amount of cullet (broken glass pieces) is added to reduce the melting temperature.
• The batch is then melted at a temperature greater than $2000°C$ in a furnace.
• Molten glass is then moulded and given the shape of sheets or bottles.
• In the end, the glass is cooled down over a range of temperature by the process of annealing.