Made from the plant fiber cellulose, paper as we know it today was first created in China around 2,000 years ago. By the time the printing press was invented in the 15th century, its use had spread to all continents. With all of this in mind, it’s easy to imagine a world without this valuable material. More than 400 million tons of paper and cardboard are produced worldwide each year, half of which comes from recycled sources.
PAPER RECYCLING
Approximately 50% of paper recycling comes from the industrial sector. The materials include shredded paper, waste from producers and manufacturers as well as materials that never reach consumers, such as unsold newspapers and magazines. Approximately one third of recyclable materials come from households, while almost all types of paper can be recycled, such as newspapers, cardboard boxes, packaging, envelopes, magazines, catalogs, wrapping paper and much more.
Recycled paper and cardboard have significant advantages over other forms of disposal such as landfilling or incineration. There is an urgent need to stimulate demand for products containing high levels of fiber, mainly for environmental purposes.
Paper can be recycled 4 to 6 times. Each time paper is recycled, its fibers become shorter, weaker and must be enriched with additional pulp during the production process to maintain their strength and quality characteristics. Through this process, recycled paper and the product derived from forests complement each other ecologically and economically.
Paper recycling follows a series of steps that depend on the type of paper and its degree of deterioration.
STAGES
Separation : Paper products must be separated according to their composition and degree of deterioration. Many times different types of paper can be mixed. Materials such as cardboard boxes cannot be processed together with others.
Compression : Large quantities of paper are packaged using hydraulic machines that exert enormous pressure to compress the material into a cube shape that has more economical transportation costs.
Shredding : The recycled fibers are chopped into smaller pieces and mixed with water to create a pulp. It is then turned into a type of sludge.
Washing : The pulp is washed, recovered and cleaned, then converted into a type of sludge and filtered through screens and other separation processes to remove all foreign elements such as ink, dirt, plastic and metals. Pigments, coatings and other additives may be added to the process. The water is continuously drained and cleaned for reuse.
Bleaching : To give the paper its white color, the pulp is bleached using hydrogen peroxide and chlorine.
Compression : The final paper result is a sheet which is compressed between large discs to remove residual water and ensure softness and thickness. The nearly dry sheet is passed through heating discs to evaporate all the water.
Reels : The finished paper passes through large reels ready to be made into a new product.
SPECIAL TREATMENTS
Sometimes the ink cannot be removed from recycled paper. In these cases the ink is dispersed in the pulp, giving the recycled paper a grey colour. In case it can be removed, there are two ways to use it:
Washing : During the pulping process, chemicals may be used to remove the ink from the paper and allow it to be washed away with large amounts of water.
Flotation : Air can be blown through the pulp to create a foam that will absorb at least half of the ink.
APPLICATIONS
Recovered paper can be used to create new products that will be produced entirely from recovered material or mixed with virgin. The most common applications are newspapers, tissues, etc. Some common products are the following:
- Cereal boxes
- Egg packaging
- Grocery bags
- Cellulose insulation materials
INFORMATION
- For every ton of paper recycled, 31 trees, 4,000 kWh of energy, 1.7 barrels (270 liters) of oil, 10.2 Btu of energy, 26,000 liters of water and 3.5 m3 of landfill space are saved.
- Burning the same ton of paper would create 750 kilograms of carbon dioxide.
- Paper recycling saves 65% of the energy required to produce new paper and reduces water pollution by 35% and air pollution by 74%.
- Recycling 1 ton of corrugated paper saves 390 kWh of energy, 1.1 barrels (176 liters) of oil, 6.6 million Btu of energy, and 5 cubic meters of landfill space.
- Recycling cardboard boxes requires only 75% of the energy required to create new ones.
Source: www.bir.org
