The step by step process of Paper Recycling
Recyclers and paper merchants collect the paper materials from collection points such as trash bins, paper stores, paper scrap yards, and commercial outlets that generate paper waste. Paper is collected from the bin and deposited in the large recycling container along with the paper from the other recycle bins. After collection, they are then measured, graded for quality, and hauled to recycling paper mill facilities.
This is the first process in the paper recycling process. Once the paper is collected from the recycle bins it is taken to the recycling plant where the waste paper is sorted and separated into types and grades.
With the arrival at the paper mill recycling facility, the papers are further checked for quality (cleanliness and type of paper) and quantity as purchasing contracts are issued based on these checks. Checking of the paper quality is also used to determine whether the type of waste paper is accepted or rejected. There are recyclers that accept mixed grades of recovered paper while some only accept preferred quality of waste paper grades.
Once accepted at the recycling facility, the papers are further sorted based on quantity and paper value by assessing the materials that were used to make the paper. In most cases, the papers are classified according to their surface treatment and structure.
For instance, the very thin lightweight paper materials like newspapers are put separately from the thick paper materials like the ones used as paper folders. Sorting is important since paper mills produce different grades of paper materials based on the materials being recovered.
- Shredding and Pulping
Once sorting is finished, the next step involves shredding followed with pulping. Shredding is done to break down the paper materials into small bits. After the material is finely shredded to bits, it is mixed with water and chemicals to breakdown the paper fiber materials. It turns the paper materials into a slurry substance, a process termed as pulping.
During the process of pulping, a large amount of water is added to the waste paper to produce pulp. Once pulp is produced it is then passed through a series of screens to remove larger pieces of contaminants for e.g.: inks, staples, plastic film and glue. The pulp material is then mixed up with new pulp to help the slurry substance solidify and form a firmer end product. The clean paper pulp is then placed in the machine that uses centrifugal cleaning to spin more of the debris from the paper pulp.
- Filtering, conterminal removal and De-Inking
The slurry substance is then taken through a comprehensive filtering process to get rid of all the non-fibrous foreign materials present or any impurities such as strings, tape or glue. The pulp further goes into a chamber where contaminants like plastics and metals staples are removed by use of a centrifuge-like process. Light materials such as plastics float on top while the heavy materials like metals fall to the bottom for elimination.
The next process, de-inking, involves putting the pulp in a floatation device made up of chemicals and air bubbles that takes away any form of dyes or ink to enhance purity and whiteness. Hydrogen peroxide may also be used to further bleach the pulp. This entire step is also called the cleaning process as it cleans the pulp over and over to ensure it is ready for the final processing stage.
- Finishing for reuse
This is the final stage of paper recycling. The cleaned pulp is blended with new production materials after which, it is put to dry on a flat conveyor belt and heated cylindrical surfaces. As the pulp dries, it is passed through an automated machine that presses out excess water. By the time the pulp is solid, it is passed through steam heated cylinders that facilitates the formation of flattened long rolls of continuous sheets of paper.
The resultant paper sheets are then trimmed, rolled, and sent to various business outlets or manufactures that use paper to make their products. Newspaper printing, wrapping papers, printing papers, and blown-in cellulose insulators are a few examples of areas where recycled papers are used.