However, fibres cannot be recycled indefinitely. Each cycle shortens and weakens the cellulose chains. On average, a paper fibre can be reused between before it becomes too short to form a coherent sheet. At that point, the residue is often converted into lower-grade products like egg cartons or tissue paper, or used as a source of biofuel.
Let’s begin with . The raw material is, of course, wood. Softwood species like pine and spruce are preferred because of their long cellulose fibres, which produce strong paper. The process starts with debarking and chipping the logs. These chips are then subjected to either a mechanical or chemical pulping process. paper production and recycling ielts listening
Stage four is , arguably the most complex step. Air bubbles are forced through the pulp while a chemical – a surfactant – attaches to the ink particles. The bubbles rise to the surface, forming a frothy layer of ink that is skimmed off. This process can remove up to 90% of printing ink. However, fibres cannot be recycled indefinitely
The fifth stage is , where the recovered fibres are beaten to swell and roughen them, improving their ability to bond. Finally, stage six: paper making , where the cleaned pulp is diluted, spread onto a wire mesh screen to drain water, pressed between rollers, and then heated to dry. At that point, the residue is often converted
Subject: Environmental Science / Industrial Processes Difficulty: IELTS Listening Section 4 Good morning. Today, we’re going to explore the lifecycle of paper, focusing on two interconnected stages: primary production from virgin materials, and secondary production through recycling. This is a critical topic, as the global demand for paper products is projected to rise by nearly 40% over the next decade.
The recycling sequence involves six key stages. First, , where paper is graded by type and quality – for instance, office paper is separated from corrugated cardboard. Next is pulping , where the paper is mixed with warm water and agitated in a huge vat called a pulper, breaking it down into individual fibres.