Pulp (paper)

Structure of fibres of pulp
Pulp at a paper mill near Pensacola, 1947

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.


Five seminal steps in ancient Chinese papermaking outlined in a woodcut.

Pulp for papermaking was produced by macerating mulberry bark as early as the 2nd century in Han dynasty China, where the invention of paper is traditionally attributed to Cai Lun.[1] Lu Ji, in his 3rd century commentary on the Classic of Poetry, mentions that people residing south of the Yangtze River would traditionally pound mulberry bark to make paper or clothing.[2] By the 6th century, the mulberry tree was domesticated by farmers in China specifically for the purpose of producing pulp to be used in the papermaking process. In addition to mulberry, pulp was also made from bamboo, hibiscus bark, blue sandalwood, straw, and cotton.[2] Papermaking using pulp made from hemp and linen fibers from tattered clothing, fishing nets and fabric bags spread to Europe in the 13th century, with an ever-increasing use of rags being central to the manufacture and affordability of rag paper, a factor in the development of printing.[3] By the 1800s, demand often exceeding the available supply of rags, and also the manual labor of papermaking resulted in paper being still a relatively pricey product.[3]

Using wood pulp to make paper is a fairly recent innovation, that was almost concurrent to the invention of automatic papermaking machines, both together resulting in paper and cardboard becoming an inexpensive commodity in modern times.[3] Although the first use of paper made from wood pulp dates from 1800, as seen in some pages of a book published by Matthias Koops that year in London,[3] large-scale wood paper production began with the development of mechanical pulping in Germany by Friedrich Gottlob Keller in the 1840s,[4] and by the Canadian inventor Charles Fenerty in Nova Scotia,[5] Chemical processes quickly followed, first with J. Roth's use of sulfurous acid to treat wood, then by Benjamin Tilghman's U.S. patent on the use of calcium bisulfite, Ca(HSO3)2, to pulp wood in 1867.[6] Almost a decade later, the first commercial sulfite pulp mill was built, in Sweden. It used magnesium as the counter ion and was based on work by Carl Daniel Ekman. By 1900, sulfite pulping had become the dominant means of producing wood pulp, surpassing mechanical pulping methods. The competing chemical pulping process, the sulfate, or kraft, process, was developed by Carl F. Dahl in 1879; the first kraft mill started, in Sweden, in 1890.[6] The invention of the recovery boiler, by G.H. Tomlinson in the early 1930s,[4] allowed kraft mills to recycle almost all of their pulping chemicals. This, along with the ability of the kraft process to accept a wider variety of types of wood and to produce stronger fibres,[7] made the kraft process the dominant pulping process, starting in the 1940s.[6]

Global production of wood pulp in 2006 was 175 million tons (160 million tonnes).[8] In the previous year, 63 million tons (57 million tonnes) of market pulp (not made into paper in the same facility) was sold, with Canada being the largest source at 21 percent of the total, followed by the United States at 16 percent. The wood fiber sources required for pulping are "45% sawmill residue, 21% logs and chips, and 34% recycled paper" (Canada, 2014).[9] Chemical pulp made up 93 percent of market pulp.[10]

Other Languages
العربية: لب ورق
čeština: Dřevovina
Cymraeg: Mwydion papur
Deutsch: Holzstoff
فارسی: خمیر کاغذ
français: Pâte à papier
한국어: 펄프
हिन्दी: लुगदी
hrvatski: Drvenjača
Bahasa Indonesia: Pulp
lietuvių: Plaušiena
Bahasa Melayu: Pulpa
Nederlands: Pulp (organisch)
日本語: パルプ
norsk: Papirmasse
norsk nynorsk: Papirmasse
oʻzbekcha/ўзбекча: Defibrer
polski: Ścier
português: Polpa de celulose
slovenčina: Buničina (papier)
svenska: Pappersmassa
Türkçe: Kâğıt hamuru
українська: Деревна маса
Tiếng Việt: Bột giấy
中文: 木浆