recycling of paper and board

RECYCLING OF PAPER AND BOARD

What? Why?Convert wastes into reusable material.Recycling is a form of reuse that requires

changing or reprocessing an item or natural resource.

Recycling helps extend the life and usefulness of something that has already served its initial purpose by producing something that is useable.

History1031-Japan begins the first recorded use of

waste paper for making new paper.  All documents and paper are recycled and repulped into new paper sold in paper shops. 

1690-The recycled paper manufacturing process is introduced.

StepsCollection and TransportationStorageRepulping and screeningCleaningDe-inkingRefiningPapermaking

Collection and Transportation

Contd…You may take your sorted paper to a local

recycling center or recycling bin. Often, a paper stock dealer or recycling center will collect recovered paper from your home or offi ce. Your local dealer can tell you the options available in your community.

At the recycling center, the collected paper is wrapped in tight bales and transported to a paper mill, where it will be recycled into new paper.

Storage

Contd..Paper mill workers unload the recovered paper

and put it into warehouses, where it is stored until needed.

The various paper grades, such as newspapers and corrugated boxes, are kept separate, because the paper mill uses different grades of recovered paper to make different types of recycled paper products.

When the paper mill is ready to use the paper, forklifts move the paper from the warehouse to large conveyors.

Repulping and Screening

Contd…The paper moves by conveyor to a big vat called a

pulper, which contains water and chemicals. The pulper chops the recovered paper into small

pieces. Heating the mixture breaks the paper down more quickly into tiny strands of cellulose (organic plant material) called fi bers. Eventually, the old paper turns into a mushy mixture called pulp.

The pulp is forced through screens containing holes and slots of various shapes and sizes. The screens remove small contaminants such as bits of plastic and globs of glue. This process is called screening.

CleaningMills also clean pulp by spinning it around in large cone-shaped cylinders. Heavy contaminants like staples are thrown to theoutside of the cone and fall through the bottom of the cylinder. Lighter contaminantscollect in the center of the Cone and are removed.

Deinking

Contd..Sometimes the pulp must undergo a “pulp

laundering” operation called deinking (de-inking) to remove printing ink and “stickies” (sticky materials like glue residue and adhesives).

Papermakers often use a combination of two deinking processes. Small particles of ink are rinsed from the pulp with water in a process called washing. Larger particles and stickies are removed with air bubbles in another process called flotation.

Refining, Bleaching and Color Stripping

Contd..During refining, the pulp is beaten to make the recycled

fibers swell, making them ideal for papermaking. If the pulp contains any large bundles of fibers, refining separates them into individual fibers.

If the recovered paper is colored, color stripping chemicals remove the dyes from the paper.Then, if white recycled paper is being made, the pulp

may need to be bleached with hydrogen peroxide, chlorine dioxide, or oxygen to make it whiter and brighter.

If brown recycled paper is being made, such as that used for industrial paper towels, the pulp does not need to be bleached.

Paper making

Contd…The pulp is mixed with water and chemicals to make

it 99.5% water.This watery pulp mixture enters the headbox, a giant

metal box at the beginning of the paper machine,and then is sprayed in a continuous wide jet onto a huge flat wire screen which is moving very quickly through the paper machine.

On the screen, water starts to drain from the pulp, and the recycled fi bers quickly begin to bond together to form a watery sheet.

The sheet moves rapidly through a series of felt-covered press rollers which squeeze out more water.

Contd..The sheet, which now resembles paper,

passes through a series of heated metal rollers which dry the paper. If coated paper is being made, a coating mixture can be applied near the end of the process, or in a separate process after the papermaking is completed. coating gives paper a smooth, glossy surface for printing.

Finally, the finished paper is wound into a giant roll and removed from the paper machine

Board RecyclingCollection

The first step in the cardboard recycling process is collecting the materials to be recycled. Check with your recycling center to see what types of cardboard it( Ordinary Grade /Medium Grade/ High Grade). Businesses should contact the recycling center to have a cardboard recycling bin placed on site to collect boxes.

SortingOnce the cardboard materials reach the recycling center, they are

sorted according to what they're made of. The University of Oregon identifies two types of cardboard for recycling: boxboard and corrugated cardboard. Boxboard includes cereal boxes, cardboard drink containers or any type of thin, non-coated cardboard. Corrugated cardboard refers to the large packing boxes typically used to transport goods.

PulpingOnce the cardboard has been sorted, the materials are soaked in

a mixture of water and chemicals designed to break down the paper fibers and create a pulp. According to Being Earthly, once the fibers are thoroughly broken down, they are combined with new pulp, usually from wood chips. This combination strengthens the weakened fibers and eventually helps them to solidify.

Filtering and De-InkingThe pulpy material is moved through a series of filters to strain

out foreign materials that may still be present, such as glue or tape. The pulp is put into a flotation device filled with chemicals that strip off inks or dyes. According to the University of Oregon, this stage cleans the pulp thoroughly and prepares it for the finishing stage.

FinishingDuring the finishing stage, the cleaned pulp is mixed with

virgin materials and dried on a flat conveyor belt or table. As it dries, the material is fed through a machine that squeezes out excess water and helps the fibers to form a solid sheet called a linerboard. According to Being Earthly, the linerboard is shipped to manufacturing companies where it may be used to make new boxboard or corrugated materials.

Slides 2-6 –prabha7-10-praga11-13-preetha14-18-ranjithboard-Radhi devi

Just for study only those explanation slides….while doin seminar no need to show those slides..just stay on the picture slides.