How Paper is Recycled
Recycling paper is one of the best ways to save the trees and protecting the environment. Nearly 80% of the paper we use can be recycled.
- The process of recycling starts with sorting the paper. This can be done at home or at a recycling center. The paper is sorted by removing any contaminants like plastic, metal or other trash. Paper stained with food is also removed during this process.
- The papers are then tied and transported to warehouses for storage. From there they are transferred to the pulper.
- The pulper is a large vat that has chemicals and water. The paper is chopped into tiny pieces and then heated in the vat. This turns the cellulose fibers into mush.
- The mushy pulp is then screened. Basically the pulp is pushed through screens that have holes and slots of different shapes and sizes.
- After screening, the pulp is cleaned further to remove any contaminants by spinning the mushy mixture. Heavy objects like staples, paper clips, plastic pins etc are thrown from the cylindrical cone shaped vats, while lighter particles gather in the center from where it is safely removed.
- After this, depending on the paper, the pulp might go through the de-inking phase. This process removes printing ink and glue residues and adhesives.
- Deinking is a two-stage process. The washing stage involves rinsing pulp with water to remove the ink particles. However larger and sticky particles might need the floatation process.
- For this the pulp is put in floatation vat in which air and chemicals known as surfactants are added. Ink and other particles attach themselves to air particles, float to the surface where they are removed as scum.
- The paper is then treated further to separate all of the color particles from the mush. After this, if white paper is going to be made then hydrogen peroxide, oxygen or chlorine dioxide is used to bleach it. If cardboard is to be made, then the pulp is not bleached.
- The pulp is then sprayed onto wire screens, which drains the water and bonds the recycled fibres to form a watery paper sheet. This watery sheet is pressed through a number of press rollers to remove all the water. It is then dried using heated metal rollers and wound into a giant roll. Each roll can be as wide as 30 feet and weight as much as 20 tons. Recycled paper is ready.
Photo by Roger Price