Why do we have to separate the different colours when recycling glass

A. Asked dooza recently, to see the replies click here. Here is the AnswerBank's fuller response:

As clear glass is usually recycled back into new clear glass and coloured glass is recycled back into new coloured glass it is more efficient to sort the glass before the recycling process begins. Glass sent for recycling is usually broken, but if it has been sorted according to colour beforehand then it doesn't matter as it isn't necessary to separate even minute shards of glass.

Q. How is glass recycled

A. Firstly, all unwanted non-glass materials are removed then the collected bottles and jars are crushed into cullet, the industry's term for used glass, to reduce the volume. The cullet then passes through a magnetic device which removes bottle tops and a vacuum process removes any plastic and paper stuck to the glass.

The clean cullet is then sent to the glass container manufacturer where it is mixed and fed into a furnace with additional raw materials. Cullet melts at a much lower temperature than the sand, lime and soda from which glass is initially made, using 30% less energy. The molten glass is then fed into bottle making machines.

The recycled glass is of the same quality as the original.

Q. What happens to any paint or ink on the glass as it is recycled

A. The furnaces high temperatures destroy it.

Q. Why recycle glass

A. Making products from recycled glass uses less energy and produces less pollution than starting from scratch. When just one glass bottle is recycled the energy saved could light a 100W bulb for four hours.

Each household produces about 1 tonne of rubbish annually, amounting to about 27 million tonnes for the UK each year, of which almost 10% is glass. So, by recycling glass you can cut waste disposal costs.

Q. What can recycled glass be used for

A. Recycled glass is made into new bottles, jars, insulation and other construction materials. Glass can be recycled indefinitely without any loss of quality

Q. My local recycling scheme won't take light bubs, why not

A. Because some glass material, such as window glass, ceramics, light bulbs or ovenware, can damage a glass manufacturer's furnace.

Do you want to know how another recycling process works Just click here to ask

by Lisa Cardy