Chemical pulp

Chemical pulp is a type of pulp used in the production of paper. It is produced by chemically treating wood to separate the cellulose fibers from the other components of the wood, such as lignin and hemicellulose. This process results in a pulp that is stronger and more durable than mechanical pulp.

History

The production of chemical pulp dates back to the mid-19th century, when the first chemical pulping processes were developed. The sulfite process, patented in 1867, was the first widely used method for producing chemical pulp. This was later supplaced by the kraft process, which was developed in the late 19th century and is still the most common method for producing chemical pulp today.

Production

The production of chemical pulp involves several steps. First, the wood is debarked and chipped. The wood chips are then cooked in a solution of chemicals at high temperature and pressure. This breaks down the lignin and hemicellulose, freeing the cellulose fibers. The resulting pulp is then washed to remove the remaining chemicals and lignin.

There are several different methods for producing chemical pulp, including the kraft process, the sulfite process, and the soda process. Each of these processes uses a different combination of chemicals to break down the wood.

Uses

Chemical pulp is used in a variety of applications. It is most commonly used in the production of paper, where it provides strength and durability. It is also used in the production of paperboard, tissue paper, and other paper products.

In addition to its use in paper production, chemical pulp is also used in the production of cellulose derivatives, such as cellophane and rayon.

Environmental impact

The production of chemical pulp has a significant environmental impact. The pulping process produces a large amount of waste, including spent cooking chemicals and lignin. These waste products can be harmful to the environment if not properly managed.

However, many pulp mills have implemented measures to reduce their environmental impact. These include the recovery and reuse of cooking chemicals, and the use of lignin as a biofuel.

See also

• Pulp mill
• Bleaching of wood pulp
• Paper recycling