Production Process and Technologies

Conventional Float Production Process

Conventional Float Production Process

Understanding the Glass Production Process

The float glass production process has one of the largest environmental impacts. To better understand the environmental aspects, we must first define the float glass production process.

The raw materials

The basic raw materials used in flat glass production are:

  • Glass-forming materials: silica sand and glass cullet
  • Intermediate and modifying materials such as sodium carbonate, dolomite, limestone, sodium sulphate, feldspar and blast furnace slag
  • Colouring and coating agents such as iron oxide and other metallic compounds

The float process

During float glass production, the raw materials are mixed together and melted in the furnace to form molten glass which is then poured into a bath of molten tin. The furnace uses air and natural gas combustion to melt the raw materials. As the glass cools and solidifies, it floats in the tin bath forming a glass ribbon. At this point, coatings can be applied on the glass at the end or just after the tin bath. The glass ribbon subsequently passes on to a zone for annealing where it cools down gradually while being carried on rollers and to be cut into sheets.

Further processing

After the glass is cooled down, it can be processed into other products. For example:

  • Glass for mirrors can be painted and silvered
  • Glass for architectural purposes (buildings, furniture etc.) can be coated, made into double glazing units, tempered, enamelled, painted, laminated, etched, etc.