sulfiteprosessit

Sulfite processes are a group of chemical processes used in the paper industry to bleach wood pulp and remove lignin, a complex organic polymer that binds cellulose fibers together. The most common sulfite processes are the kraft process and the semi-chemical process. The kraft process, also known as the sulfate process, is the most widely used method for producing wood pulp. It involves cooking wood chips with a mixture of sodium hydroxide and sodium sulfide at high temperatures and pressures. The resulting pulp is then washed and bleached using various chemical and mechanical methods. The semi-chemical process, on the other hand, uses a lower concentration of sodium hydroxide and sodium sulfide, resulting in a pulp with a higher lignin content. This pulp is then bleached using chlorine-based chemicals. Both processes have their advantages and disadvantages, with the kraft process being more environmentally friendly but less efficient in terms of pulp yield, and the semi-chemical process being more efficient but more polluting. Sulfite processes are also used in the production of other chemicals, such as sodium sulfite, which is used as a preservative in food and beverages.