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Tuesday, August 11, 2009

the aluminium can recycling loop


the aluminium can recycling loop

It's up to us to keep the aluminium can recycling loop going! Here's how it works:

aluminium recycling loop

  • Stage 1: Collection
  • Stage 2: Recycling
  • Stage 3: Rolling
  • Stage 4: Can Making
  • Stage 5: Filling
  • Stage 6: Selling

Stage 1: Collection

Aluminium cans are collected for recycling in a number of ways:

  • can banks - located at supermarkets and council recycling sites. These are emptied by waste management companies or your local council
  • kerbside recycling schemes - operated by your local council to make recycling at home as convenient as possible.
  • Cash for cans centres - where you can exchange empty aluminium cans for cash

Once collected the cans are delivered to one of Alcan's regional aggregation centres. Here the cans are checked to ensure they don't contain any steel, plastic, paper, dirt or excess liquid as these can disrupt the recycling process. They are then baled and transported to the Used Beverage Can Recycling Plant.

Stage 2: Recycling

The recycling process has four stages.

Shredding: Mechanical hammers shred the flattened cans into small pieces, about the size of a 50p.
Decoating: Decoration is removed by blowing hot air (500 degrees celsius) through the shreds.
Melting: The shreds are melted in a furnace heated to 750 degrees celsius.
Casting: The molten metal flows into moulds and is cooled by jets of water. As it cools and the metal hardens and an 'ingot' is formed.

Each ingot weighs 27 tonnes. It is 15 metres long and contains enough metal to make 1.5 million drink cans.

The ingot is now transported from Warrington to the rolling mill.

Stage 3: Rolling

The ingots are pre-heated to 600 degrees celsius and undergo their first rolling. They are then 'cold rolled' to the exact specification and thickness required by the can maker.

Stage 4: Can Making

The aluminium sheet is lubricated and fed through a cupping press. This cuts, or blanks, thousands of shallow cups. The sides of the cups are raised to form the can shape by being rammed through a series of rings. The can is trimmed and washed ready for decorating.

The inside and outside of the can is treated with a lacquer. This forms the base coat for the external decoration and prevents the contents reacting with the metal inside.

After the decoration has been applied the cans are dried in an oven and then passed through a necker/flanger to prepare them to take the can end.

Stage 5: Filling

Cans are cleaned using high pressure air and water. Then the air is extracted and at the same the can is filled with carbon dioxide gas (CO2). The liquid contents are then added and the can ends are attached and mechanically sealed.

Around 2000 cans are filled by this process every minute.

The cans are then packed ready for despatch to the distributor or retailer.

Stage 6: Selling

The final stage of the loop is when the cans are delivered to the retailer, ready for you to buy - again! This could be your local supermarket, corner shop or a vending machine in your office or leisure centre.

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