Glass Recycling, Tips for the Recycling of Glass and What Happens to Glass Sent for Recycling

Background

Glass has been used by humans for a very long time. Glass is believed to have first been made by the Phoenicians around 5000 years ago and Egyptians were hand blowing glass bottles in the first century BC.

How is Glass Made

Glass is made by melting silica sand, limestone and soda ash in a furnace at around 1500C. An important addition to this mix is called cullet. Cullet is recycled, crushed glass that can be up to 40% of the mixture.

The molten glass mixture is then made into glass products like bottles and jars.

Firing the furnace to make glass is an energy intensive procedure. Recycled glass melts at lower temperatures that virgin raw materials and using recycled glass can result in energy savings of around 25%.

Recycling Glass

Not all glass can be readily recycled. All glass bottles and containers can and should be recycled repeatedly. Window glass, lightbulb glass, mirrors and ceramic materials like cups, saucers and plates, cannot be readily recycled and should not be added to the glass recycling stream. Even a very small addition of unsuitable material to large batch of recyclable glass can result in the whole lot being contaminated.

What Happens to Glass Items Sent for Recycling?

After you put glass items out for recycling they go through the stages of :

• Separation
• Storing and Transport
• Beneficiation

Separation

At a specialist materials recycling facility glass is separated from other materials in a mixed recycling stream. It is then further sorted by glass colour; clear, green or amber (brown).

Storing and Transport

Depending upon location and demand, the glass containers are either stored in large bins or skips or sent for processing. The next stage of processing may occur onsite at large recycling facilities or be sent by truck to another location.

Beneficiation

Beneficiation is a process were items associated with the sorted glass are removed to stop contamination. The things removed include bottle tops, labels, metal parts or other ceramics. The single coloured glass is then crushed and sent to the furnace.

Tips for Recycling Glass

Following a few simple tips makes glass recycling easier:

• Rinse bottles and jars to remove food waste. Although the waste will burn off in the furnace, it can attract vermin and make the recycling stream a smelly and messy place. Plus it may contaminate other materials in a mixed waste stream, like paper.
• Remove lids from jars and bottles.
• Try not to break the glass. Although the glass will eventually be broken, solid containers are safer and easier to sort. 
• If your local council or recycling authority has a system that has separate recycling bins, make sure you use the correct one. 
• Don't contaminate the recycling system with broken cups or plates, old light bulbs, glass windows, or mirrors. It may be possible to recycle these items separately, but not with the glass from bottles and jars.

Can Contaminated Glass Be Used

Contaminated glass can be an usual colour, include flaws, have less strength and other poor properties. Sometimes glass contaminated with other material can still be used for other applications. These include use as grit for sandblasting and as road base.