How is pulp made into paper?

pulping process
paper making process

Paper is made of the pulp through the processes of pulp blending, paper processing and paper making. To put it simply, paper is to be added with various auxiliary chemicals into the pulp, then purify and screen the latter again and finally be produced out by pressing dehydration, drying, and cutting. Therefore, pulping is the first step in paper making. Generally, there are three ways to convert raw material into pulp: mechanical pulping, chemical pulping and semi-chemical pulping. Pulp adjusting is another key point. The strength, color, printability and life of paper are directly related to it.

Common pulp adjusting process can be roughly divided into the following three steps: A. bulk; B. beating; C. adding glue and filling. The next step is the paper making process. The main work of the paper making department is to evenly interweave and dehydrate thin paper materials, and then carry out drying, calendering, rolling, cutting, selecting and packing processes. Therefore, common processes are as follows: A. screening of paper materials; B. net section; C. press section; D. calendar; E. roll paper; G. cutting, selecting and packing.


Pulp is a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibres from wood, fiber crops, waste paper, or rags. Many kinds of paper are made from wood with nothing else mixed into them. This includes newspapers, magazines and even toilet paper. Pulp is one of the most abundant raw materials.

A pulp mill is a manufacturing facility that converts wood chips or other plant fibre source into a thick fibre board which can be shipped to a paper mill for further processing. Pulp can be manufactured using mechanical, semi-chemical or fully chemical methods (kraft and sulfite processes). The finished product may be either bleached or non-bleached, depending on the customer requirements.

A paper machine (or paper-making machine) is an industrial machine which is used in the pulp and paper industry to create paper in large quantities at high speed. Modern paper-making machines are based on the principles of the Fourdrinier Machine, which uses a moving woven mesh to create a continuous paper web by filtering out the fibres held in a paper stock and producing a continuously moving wet mat of fibre. This is dried in the machine to produce a strong paper web.

The pulp produced up to this point in the process can be bleached to produce a white paper product. The chemicals used to bleach pulp have been a source of environmental concern, and recently the pulp industry has been using alternatives to chlorine, such as chlorine dioxide, oxygen, ozone and hydrogen peroxide.

Chemical pulp is produced by combining wood chips and chemicals in large vessels called digesters. There, heat and chemicals break down lignin, which binds cellulose fibres together, without seriously degrading the cellulose fibres. Chemical pulp is used for materials that need to be stronger or combined with mechanical pulps to give a product different characteristics. The kraft process is the dominant chemical pulping method, with the sulfite process second. Historically soda pulping was the first successful chemical pulping method.