Paper pulp is made from wood or cotton fibers that are cooked in a solution of water and chemicals to create a viscous slurry. The pulp undergoes washing and bleaching before being dried and processed. Wood-based pulping uses hardwood and softwood varieties, while cotton pulp is made from raw cotton waste or cotton rags. The finished pulp can be used immediately, stored in vats, or dried and packaged for later use.
Paper pulp is a term used to describe various slurry preparations used to make paper and paper products. The pulps are produced either from wood or from cotton fibres, and are obtained by “cooking” the wood shavings or cotton fibers in a solution of water and various chemical products to reduce them to a consistency suitable for lamination of the various final products. Both hardwoods and softwoods harvested from sustainable sources are used to make wood-based paper pulp. In the case of cotton-based pulps, raw cotton waste or recycled rag clippings are used to produce higher quality papers than those made with wood pulp. After production, the pulp can be used immediately, stored in vats or dried and packaged for later use.
Most commercial paper products are made from wood pulp or cotton fiber. With both feedstock sources, pulp is typically made by “cooking” wood chips or cotton fibers at high temperatures and pressures in a digester to reduce or break down the material to form a viscous slurry. The raw material is cooked in a solution of water and chemicals such as sodium hydroxide, sodium sulfide and calcium carbonate, known as white liquor. Once the cooking process is complete, the pulp typically undergoes several stages of washing and bleaching before being dried and processed.
Wood-based pulping processes begin with the harvesting of adequate wood stocks from waste sources of sawmilling, logging, or thinning operations. These stocks include hardwood and softwood varieties, including pine, spruce, and birch. The wood is then cleared of bark and debris and chipped to produce a fine aggregate. The chips are placed in a heated pressure vessel known as a digester along with a solution of water, sodium hydroxide and sodium sulfide, where they are pressure cooked for approximately 90 minutes. This process breaks down the lignin, or cell-binding agents, in the wood, reducing the chips to a thick pulp.
Cotton paper pulp is produced from one of two raw material sources: raw cotton waste and cotton rags. Cotton waste is long, fine fibers that surround the seed on a cotton boll, while rags are simple scraps of clothing and fabrics. These cotton fibers are rich in cellulose and have no lignin, resulting in a whiter, stronger final product that requires less bleaching. Cotton pulp is made using a process similar to wood pulp with the fibers cooked under pressure in a solution of water and chemicals such as calcium carbonate and hydrogen peroxide. Because of their strength and longevity, cotton-based papers are commonly used as archival media for the production of artwork and currency.
In both the wood pulp and cotton pulp processes, the pulp undergoes several washing stages after the initial firing is complete. In addition to washing, wood pulp is typically also bleached to neutralize any residual lignin staining in the pulp. The finished pulp is then used immediately or can be stored moist in vats, or dried, cut and packaged for distribution to paper manufacturers.
Protect your devices with Threat Protection by NordVPN
