Hiomaprosessit

Hiomaprosessit refers to the processes involved in the manufacturing of pulp, a fibrous material derived from wood, plant fibers, or recycled paper, which is the primary raw material for papermaking. These processes aim to separate the cellulose fibers from the lignin and other non-cellulosic components of the source material. There are two main categories of pulping processes: mechanical pulping and chemical pulping.

Mechanical pulping, also known as groundwood pulping, involves grinding wood logs against a stone or using refiners to separate the fibers. This method yields a high percentage of pulp from the wood but results in fibers that are shorter and weaker, and the lignin is largely retained, leading to paper that yellows over time. It is often used for newsprint and paper grades where brightness and strength are not paramount.

Chemical pulping, on the other hand, uses chemical solutions and heat to dissolve the lignin and separate the cellulose fibers. The most common chemical pulping processes are the Kraft process (sulfate process) and the sulfite process. The Kraft process is widely used due to its efficiency and the strength of the resulting pulp. It uses alkaline chemicals, primarily sodium hydroxide and sodium sulfide, to break down lignin. The sulfite process uses acidic or alkaline sulfite solutions. Chemical pulping produces stronger, purer fibers suitable for a wider range of paper products, but the yield from the wood is lower compared to mechanical pulping.

Other pulping methods include semi-chemical pulping, which combines elements of both mechanical and chemical treatments, and de-inking processes for recycling paper. The choice of hiomaprosessi depends on the desired properties of the final paper product, the type of raw material available, and economic and environmental considerations.