Scrap Recycling Forum

As early as 4000 BC glass was used in the Middle East as a glaze to decorate beads. By 1550 BC, coloured glass vessels were widespread and used for cooking and drinking. The earliest known clear glass is a vase found in Nineveh in Assyria, dating from around 800 BC, which is now in the British Museum in London.

Until the 18th and 19th centuries glass was very expensive and was used for limited applications, such as stained glass windows for churches. Large-scale glass manufacture began with the industrial revolution with the mass production of glass containers beginning at the onset of the 20th century and glass light bulb production automated in 1926.

Nowadays glass is much less expensive and is taken for granted as a packaging material in addition to its use in windows and other applications. New glass is made from a mixture of four main ingredients: sand, soda ash, limestone and other additives. These additives include iron for colour (brown or green), chromium and cobalt for colour (green and blue respectively, lead to alter the refractive index, alumina for durability and boron to improve the thermal options.

Using present technology the UK glass industry has the capacity to recycle over one million tonnes of glass each year and this coupled with the materials unique ability to be infinitely recycled without compromising its quality creates a compelling case for the recycling of glass. Despite this, glass makes up around 7% of the average household dustbin and in 2001 over 2.5 million tonnes of this material was landfilled.

The manufacture of glass uses energy in the extraction and transportation of the raw materials, and during processing as materials have to be heated together to a very high temperature. Large amounts of fuel are used and the combustion of these fossil fuels produces carbon dioxide - a greenhouse gas. In 2002 the glass industry consumed a total of 8611,000,000 kWh of energy including electricity and carbon dioxide emissions totalled 1.8 million tonnes from the fossil fuels burnt in the factories. An efficient furnace will require 4 GJ of energy for each tonne of glass melted.

Glass can be recycled indefinitely as part of a simple but hugely beneficial process, as its structure does not deteriorate when reprocessed. In the case of bottles and jars, up to 80% of the total mixture can be made from reclaimed scrap glass, called "cullet". Cullet from a factory has a known composition and is recognised as domestic cullet. From bottle banks it is known as foreign and its actual properties will not be known.

If recycled glass is used to make new bottles and jars, the energy needed in the furnace is greatly reduced. After accounting for the transport and processing needed, 315kg of CO2 is saved per tonne of glass melted.

Recycling two bottles saves enough energy to boil water for five cups of tea

In addition:

Recycling reduces the demand for raw materials. There is no shortage of the materials used, but they do have to be quarried from our landscape, so from this point of view, there are environmental advantages to recovering and recycling glass. For every tonne of recycled glass used, 1.2 tonnes of raw materials are preserved.
Recycling reduces the amount of waste glass which needs to be landfilled. Although glass is inert and is not directly hazardous to the environment, it will remain there indefinitely.
Taking part in recycling the waste we produce makes us think about the effect we are having on our environment and enables us to contribute towards a greater level of sustainability


How's, what's and where's of recycling glasstop of page
Types of glass
Glass that we are familiar with is divided into different streams based on its particular composition and use.

Container glass
Container glass is largely bottles and jars and represents around 80% of the recycled glass market. Total container glass flow is estimated at 2.23 million tonnes of which around 629,000 tonnes may be imported

On average, every family in the UKconsumes around 330 glass bottles and jars a year.
(British Glass)

Reuse
Returning bottles to the retailer and receiving the deposit in return used to be common practice. However as manufacturing plants became larger and decreased in number, bottles had to be carried further for refilling. This removed much of the financial and environmental advantages associated with returnable bottles. In addition to this, consumer preference turned to the convenience of non-returnable bottles. Milk bottles are one of the few types of glass packaging still reused (an average of 12 times). Despite the extra weight required to withstand wear and tear and the costs of cleaning, returning bottles can still be the best option when they are recovered and refilled locally. There is also the option of reusing bottles and jars as storage containers for home made wine, beer or jam.

Recycling
Many people set aside glass for recycling and either participate in kerbside collection schemes or take them to a bottle bank. The first bottle banks appeared in 1977, and there are now roughly 50,000 on some 20,000 sites around the country, usually located at civic amenity sites and supermarkets. To find your nearest bottle bank you can use the recycle bank locator at recycle-more - recycle-more offers advice for recycling at home, school and at work.

Glass can also be recovered from businesses, such as pubs and restaurants, and from companies, schools or organisations which are able to have a bottle bank on site. 600,000 tonnes of glass bottles are thrown out from pubs, clubs, hotels, restaurants and cafes every year (a quarter of the UK's waste glass containers). Up to 75% of this is currently being sent to landfill sites.

The UK has a current municipal recycling rate of 34% for container glass. This is poor when considering that Switzerland and Finland recycle more than 90% of their container waste and recycling figures of more than 50% are the norm.

Yes its true laws in Uk ..Using present technology the UK glass industry has the capacity to recycle over one million tonnes of glass each year and this coupled with the materials unique ability to be infinitely recycled without compromising its quality creates a compelling case for the recycling of glass. Despite this, glass makes up around 7% of the average household dustbin and in 2001 over 2.5 million tonnes of this material was landfilled.

Modern glass containers are manufactured using very precise, complex and highly controlled technology. However, the raw materials used are simple and abundant and the basic process was in fact first used by the Egyptians around 3000 BC!

There are four main ingredients:

* cullet (recycled glass)
* sand
* soda ash
* limestone

As much recycled glass is used as possible as this enables the other materials to melt at a lower temperature. The colour of the glass is controlled by the iron content and the addition of minor colouring agents.

Even though basic ingredients are used in vast quantities, accurate weighing and mixing to achieve precise proportions is absolutely critical. This procedure is carried out electronically in the batch house which supplies the mix to the furnace.
A typical furnace within the glass container industry will operate 24 hours a day, 365 days of the year producing around 300 tonnes of glass a day! This production of glass is continuous for the furnaces' lifetime of approximately 10 years.
Up to 90% recycled glass is mixed with raw materials and fed into the furnace where the recycled glass remelts and becomes pure and pristine again.