What is glass?
Glass is made by melting silica sand, limestone and soda ash in a furnace at around 1500° C. Recycled crushed glass, or "cullet", is added to the mixture. Cullet can make up to 40% of the total amount of material in the furnace.

The molten glass then goes to the glass bottle and jar forming machines, where it is cut into small pieces called gobs. These gobs go into moulds and are then blown into the right shape. The glass is then cooled gradually and coated with a special product that stops scuffing.

What happens to the glass bottles and jars we put out for recycling?

Step 1 - Separation
Trucks take the recycling to a Materials Recycling Facility (MRF), where it is pushed on to a conveyor belt. The glass is sorted either mechanically or by hand into three colours - clear, brown (amber) and green.

Step 2 - Storing and transporting
The used glass containers (called "cullet") are collected in large bins or skips which are then taken to the beneficiation plant.

Step 3 - Beneficiation
The single-colour cullet is put onto a conveyor belt and goes through a special process called beneficiation, which removes contamination such as bottle tops, metals, ceramics and labels. The cullet is then crushed and sent to a glass furnace where it is added to the mix.

Facts

• Glass was discovered by the Phoenicians more than 5,000 years ago.
• The Egyptians invented hand blowing glass bottles in the first century BC.
• Glass containers can be recycled over and over again.
• For every one tonne of cullet used, 1.1 tonnes of raw materials are saved.
• Recycled glass melts at a lower temperature than the raw ingredients, which can cut energy use by up to 25% and reduce greenhouse gas and heat emissions.
• The lower temperatures result in less wear on the furnace and the associated equipment.
• If glass is heavily contaminated with other materials it can be used for other purposes, such as road construction and sandblasting.
• In 2002 the recycling rate for glass in Australia was only 40%, which means 60% is still being thrown away and wasted.
  
  Recycling Tips - Sort it, check it, keep it clean
  • Remove metal and plastic lids and put them in the garbage bin.
  • Save corks and take them to the local Girl Guides for recycling.
  • Rinse the containers to make sure they are clean and won't attract pests.
  • If your recycling is separated into containers and paper/cardboard, make sure the glass bottles and jars go in with the other containers.
  • Try not to break the glass - the larger the pieces, the easier it is for the equipment at the Materials Recycling Facility to sort.
  • Never put broken cups and plates, light globes, china, or ceramics in the recycling - they contaminate the glass and prevent it from being recycled.
  • Glass mirrors and windows, either broken or whole, cannot be recycled in the recycling bin. Contact council or your local waste and recycling centre to find out what to do with them.
    
    NSW Glass Recycling
    In 2003-2004 around 106,378 tonnes of co-mingled glass 14,788 tonnes of brown glass, 5,734 tonnes of green glass and 9,510 tonnes of white glass were collected through kerbside recycling in NSW.
    
    Close the Loop and Buy It Back!
    There's no point in recycling if we don't buy back the products made from recycled materials.
    
    You can help the environment by purchasing bottles and jars made from recycled glass. Look for other products that are either made from recycled material or can be recycled, and if in doubt, don't be afraid to check with the manufacturers.
    
    Sources:
    NSW Department of Environment and Climate Change
    
    Planet Ark