Materials
Made from vegetable fibres called cellulose, paper as we know it today was first created in China more than two thousand years ago. Since the advent of the printing press in the 15th century , its use has spread across all continents to the extent that, currently, it is hard to imagine the world without this versatile material. More than 400 million tonnes of paper and cardboard are produced worldwide every year, with more than half coming from recovered sources.
Approximately 50% of recovered paper comes from industry and business. This includes paper trimmings, cuttings and shavings from manufacturers and converters, as well as goods discarded before they reach the consumer, such as unsold newspapers and magazines. Well over a third of recovered paper comes from households. Almost any used paper can be recycled, including newspaper, cardboard, packaging, stationery, direct mail, magazines, catalogues, greeting cards and wrapping paper.
Recycling used paper and cardboard has significant advantages over other disposal options - namely landfill and incineration. It is imperative to stimulate the demand for products containing high levels of recycled fibre because of their environmental benefits. The work carried out by BIR has been instrumental in encouraging the development of new markets for recovered paper.
Recycling Processes
According to industry estimates, paper can be recycled an average of 4 to 6 times. Each time recycling occurs, the fibres become shorter and weaker and virgin pulp must be introduced into paper production to maintain the strength and quality of the fibre. Through this process, recovered paper and forest-based product complement each other ecologically and economically.
The recycling of paper follows a series of steps which may vary depending on the type of paper and its degree of deterioration.
Paper sorting and baling
Baled corrugated carton
Rotary sorting station"
- Sorting: Paper products must be separated according to their composition and degree of deterioration. Different types of paper can sometimes be mixed. Others, such as paperboard, are recycled using a single-grade process, meaning that no other type of paper can be mixed in during its processing.
- Baling: Large quantities of paper are packed using hydraulic machines that apply enormous pressure to compact recovered paper into blocks that are easier and more cost-effective to transport.
- Shredding: Recovered fibre is shredded into smaller pieces and mixed with water to make pulp.
- Washing: The pulp is washed, refined and cleaned, then turned into a slush that undergoes filtering through screens and other separation processes to remove contaminants such as ink, clay, dirt, plastic and metals. Dyes, coatings and other additives can be introduced during this process. Water is continuously drained and cleaned for reuse.
- Bleaching: In order to whiten paper, the pulp can be bleached using hydrogen peroxide and chlorine.
- Pressing: The resulting paper sheet, known as ‘web’, is pressed between massive rollers to extract as much of the remaining water as possible and to ensure uniform smoothness and thickness. The semi-dry web is then run through heated dryer rollers to remove any remaining water.
- Rolling: The finished paper is processed into large rolls ready to be manufactured again into new consumer products.
Special Processes
Sometimes, ink is not removed from the recovered paper. In this case, the ink is dispersed into the pulp, giving the recycled paper a greyish tint. If the ink is to be removed, there are two different methods which can be used:
- Washing: As the paper is pulped, chemicals can be added to separate the ink from the paper and allow it to be washed away with large amounts of water.
- Flotation: Air can be passed through the pulp, producing foam that absorbs at least half of the ink, which can then be skimmed off.
Applications
Recovered paper can be used to make new products composed entirely of recovered fibre or a blend of recovered and virgin fibres. The most common applications for recovered paper include newsprint, containers and tissue. Some products commonly manufactured using recycled materials are:
- Cereal boxes
- Egg cartons
- Pencil barrels
- Grocery bags
- Cellulose insulation materials
Recycling Facts
- Recycling one tonne of paper saves up to 31 trees, 4,000 kWh of energy, 1.7 barrels (270 litres) of oil, 10.2 million Btu's of energy, 26,000 litres of water and 3.5 cubic metres of landfill space.
- Burning that same tonne of paper would generate about 750 kilograms of carbon dioxide.
- Recycling paper saves 65% of the energy needed to make new paper and also reduces water pollution by 35% and air pollution by 74%.
- Recycling one tonne of corrugated containers saves 390 kWh of energy, 1.1 barrels (176 litres) of oil, 6.6 million Btu's of energy, and 5 cubic metres of landfill.
- Recycling cardboard requires only 75% of the energy required to make new cardboard.