Wood pulp is a dry fibrous material prepared by chemically or mechanically separating the fibers which make up wood. Wood is hard fibrous lignified structural tissue produced as secondary Xylem in the stems of Woody plants notably trees but also shrubs

Pulp can be either fluffy or formed into thick sheets. The latter form is used if the pulp must be transported from the pulp mill to a paper mill. A pulp mill is a manufacturing facility that converts wood chips or other plant fiber source into a thick fiber board which can be shipped to a Paper mill for further A paper mill is a Factory devoted to making Paper from wood pulp and other ingredients using a Fourdrinier Machine or similar apparatus Pulp which is shipped and sold as pulp (not processed into paper in the same facility) is referred to as market pulp. When suspended in water the fibers disperse and become more pliable. This pulp suspension can be laid down on a screen to form a sheet of paper, and this is the primary use for wood pulp. Paper is thin material mainly used for writing upon printing upon or packaging Wood pulp is the most common material used to make paper. Paper is thin material mainly used for writing upon printing upon or packaging The timber resources used to make wood pulp are referred to as pulpwood. Pulpwood refers to Timber grown with the principal purpose of making Wood pulp for Paper production Wood pulp comes from softwood trees such as spruce, pine, fir, larch and hemlock, and hardwoods such as eucalyptus, aspen and birch. Softwood is a generic term used in Woodworking and the Lumber industries for Wood from Conifers (needle-bearing trees from the order Pinales Spruce refers to Trees of the genus Picea, a genus of about 35 species of Coniferous Evergreen trees in the Family Pinaceae This article is about the tree For other uses of the term "pine" see Pine (disambiguation. Firs ( Abies) are a genus of between 45-55 species of Evergreen conifers in the family Pinaceae. Larches are Conifers in the genus Larix, in the family Pinaceae. Tsuga (from ツガ ja 栂 the name for Tsuga sieboldii) is a genus of conifers in the family Pinaceae. The term hardwood is used to describe Wood from broad-leaved angiosperm Trees mostly Deciduous, but not necessarily in the case of tropical Eucalyptus (From Greek ευκάλυπτος meaning "well covered" is a diverse Genus of Trees (and a few shrubs the members of which Aspens are Trees of the willow family and comprise a section of the Poplar genus Populus sect Birch is the name of any Tree of the genus Betula ( Bé-tu-la) in the family Betulaceae, closely related to the

Contents 1 History 2 Manufacture of wood pulp 2.1 Harvesting trees 2.2 Preparation for pulping 2.3 Pulping 2.3.1 Mechanical pulp 2.3.2 Chemithermomechanical pulp 2.3.3 Chemical pulp 2.3.4 Recycled pulp 2.4 Bleaching 3 Environmental concerns 3.1 Forest resources 3.2 Effluents from pulp mills 4 Alternatives 5 See also 6 References 7 External links

History

Using wood to make paper is a fairly recent innovation. Paper is thin material mainly used for writing upon printing upon or packaging In the 1800s, fiber crops such as linen fibres were the primary material source, and paper was a relatively expensive commodity. Fiber crops are field crops grown for their Fibers which are used to make Paper, Cloth, or Rope. Linen is a Textile made from the Fibers of the Flax plant Linum usitatissimum. The use of wood to make pulp for paper began with the development of mechanical pulping in Germany by F. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. G. Keller in the 1840s^[1]. Chemical processes quickly followed, first with J. Roth's use of sulfurous acid to treat wood, followed by B. Sulfurous acid is the Chemical compound with the formula H2SO3 Tilghman's US patent on the use of calcium bisulfite, Ca(HSO₃)₂, to pulp wood in 1867. United States patent law was established "to promote the Progress of Science and useful Arts by securing for limited Times to Authors and Inventors the exclusive Right to their respective Calcium bisulfite (calcium bisulphite is an Inorganic compound which is the salt of Calcium cation and Bisulfite anion Year 1867 ( MDCCCLXVII) was a Common year starting on Tuesday (link will display the full calendar of the Gregorian calendar (or a Common year starting ^[2] Almost a decade later the first commercial sulfite pulp mill was built in Sweden. "Sverige" redirects here For other uses see Sweden (disambiguation and Sverige (disambiguation. It used magnesium as the counter ion and was based on work by Carl Daniel Ekman. Magnesium (mægˈniːziəm is a Chemical element with the symbol Mg, Atomic number 12 Atomic weight 24 A counter ion is an Ion, the presence of which allows the formation of an overall neutrally charged species By 1900 sulfite pulping had become the dominant means of producing wood pulp, surpassing mechanical pulping methods. Year 1900 ( MCM) was an exceptional Common year starting on Monday (link will display the full calendar of the Gregorian calendar The competing chemical pulping process, the sulfate or kraft process was developed by Carl F. The Kraft process (also known as Kraft pulping or sulfate process) describes a technology for conversion of wood into Wood pulp consisting of almost pure Dahl in 1879 and the first kraft mill started (in Sweden) in 1890. Year 1879 ( MDCCCLXXIX) was a Common year starting on Wednesday (link will display the full calendar of the Gregorian calendar (or a Common Year 1890 ( MDCCCXC) was a Common year starting on Wednesday (link will display the full calendar of the Gregorian calendar (or a Common ^[2] The invention of the recovery boiler by G. Recovery boiler is the part of Kraft process of pulping where chemicals for White liquor are recovered and reformed from Black liquor. H. Tomlinson in the early 1930s ^[1] 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 produce stronger fibers ^[3] made the kraft process the dominant pulping process starting in the 1940s. ^[2]

Global production of wood pulp in 2006 was 160 million tonnes (175 million tons)^[4]. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. In the previous year, 57 million tonnes (63 million tons) of market pulp (not made into paper in the same facility) was sold, with Canada being the largest source at 21% of the total, followed by the US at 16%. Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page The United States of America —commonly referred to as the Chemical pulp made up 93% of market pulp. ^[5]

Manufacture of wood pulp

Main article: Pulp mill

Harvesting trees

Most pulp mills use good forest management practices in harvesting trees to ensure that they have a sustainable source of raw materials. A pulp mill is a manufacturing facility that converts wood chips or other plant fiber source into a thick fiber board which can be shipped to a Paper mill for further Forest management includes a range of human interventions that affect Forest Ecosystems. One of the major complaints about harvesting wood for pulp mills is that it reduces the biodiversity of the harvested forest. Biodiversity is the variation of Life forms within a given Ecosystem, Biome or for the entire Earth. Trees raised specifically for pulp production account for 16% of world pulp production, old growth forests 9% and second- and third- and more generation forests account for the balance^[6]. Reforestation is practiced in most areas, so trees are a renewable resource. Reforestation is the restocking of existing forests and woodlands which have been depleted with native tree stock The FSC (Forest Stewardship Council) certifies paper made from trees harvested according to guidelines meant to ensure good forestry practices. ^[7]

The number of trees consumed depends whether mechanical processes or chemical processes are used. It has been estimated that based on a mixture of softwoods and hardwoods 12 meters (40 ft) tall and 15-20 centimeters (6-8 in) in diameter, it would take an average of 24 trees to produce 0. 9 tonne (1 ton) of printing and writing paper, using the kraft process (chemical pulping). The Kraft process (also known as Kraft pulping or sulfate process) describes a technology for conversion of wood into Wood pulp consisting of almost pure Mechanical pulping is about twice as efficient in using trees since almost all of the wood is used to make fiber therefore it takes about 12 trees to make 0. 9 tonne (1 ton) of mechanical pulp or newsprint. Newsprint is low-cost non-archival Paper most commonly used to print Newspapers plus other publications and advertising material [2]

Preparation for pulping

Main article: Woodchipping

Only the heartwood and sapwood are useful for making pulp. Woodchipping is the act and industry of chipping wood for pulp or processed wood products Bark contains relatively few useful fibers and is removed and used as fuel to provide steam for use in the pulp mill. Bark, also known as periderm is the outermost layer of stems and Roots of Woody plants such as Trees It overlays the Wood and consists Most pulping processes require that the wood be chipped and screened to provide uniform sized chips.

Pulping

There are a number of different processes which can be used to separate the wood fibers:

Mechanical pulp

Manufactured grindstones with embedded silicon carbide or aluminum oxide can be used to grind small wood logs called "bolts" to make "stone groundwood" pulp (SGW). Silicon carbide ( is a compound of Silicon and Carbon bonded together to form Ceramics but it also occurs in nature as the extremely rare mineral If the wood is steamed prior to grinding it is known as "pressure groundwood" pulp (PGW). Most modern mills use chips rather than logs and ridged metal discs called refiner plates instead of grindstones. If the chips are just ground up with the plates, the pulp is called "refiner mechanical" pulp (RMP) and if the chips are steamed while being refined the pulp is called "thermomechanical" pulp (TMP). Steam treatment significantly reduces the total energy needed to make the pulp and decreases the damage (cutting) to fibers. Mechanical pulps are used for products that require less strength, such as newsprint and paperboards. Newsprint is low-cost non-archival Paper most commonly used to print Newspapers plus other publications and advertising material Paperboard is a Paper -like material usually over ten mils (0

Chemithermomechanical pulp

Wood chips can be pretreated with sodium carbonate, sodium hydroxide, sodium sulfite and other chemical prior to refining with equipment similar to a mechanical mill. Sodium carbonate (also known as washing soda or soda ash), is a Sodium Salt of Carbonic acid. Sodium hydroxide ( Na[[hydroxide OH]]) also known as Lye, caustic soda and (incorrectly according to IUPAC nomenclature Sodium sulfite (sodium sulphite is a soluble compound of Sodium. The conditions of the chemical treatment are much less vigorous (lower temperature, shorter time, less extreme pH) than in a chemical pulping process since the goal is to make the fibers easier to refine, not to remove lignin as in a fully chemical process. pH is the measure of the acidity or alkalinity of a Solution. Pulps made using these hybrid processes are known as chemithermomechanical pulps (CTMP).

Chemical pulp

Main article: Kraft process

Main article: Sulfite process

Chemical pulp is produced by combining wood chips and chemicals in large vessels known as digesters where heat and the chemicals break down the lignin, which binds the cellulose fibers together, without seriously degrading the cellulose fibers. The Kraft process (also known as Kraft pulping or sulfate process) describes a technology for conversion of wood into Wood pulp consisting of almost pure The sulfite process produces Wood pulp which is almost pure Cellulose fibers by using various Salts of Sulfurous acid to extract the Lignin A digester is a device used in Papermaking which takes small Wood chips and cooks them for a number of hours to remove Lignin. Cellulose is an Organic compound with the formula, a Polysaccharide consisting of a linear chain of several hundred to over ten thousand β(1→4 Cellulose is an Organic compound with the formula, a Polysaccharide consisting of a linear chain of several hundred to over ten thousand β(1→4 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 sulfite process being second. The Kraft process (also known as Kraft pulping or sulfate process) describes a technology for conversion of wood into Wood pulp consisting of almost pure The sulfite process produces Wood pulp which is almost pure Cellulose fibers by using various Salts of Sulfurous acid to extract the Lignin

Recycled pulp

Main article: Paper recycling

Pulp can also be made out of waste paper and paperboard. Paper recycling is the process of recovering waste Paper and remaking it into new paper products Paperboard is a Paper -like material usually over ten mils (0 Recycled pulp is most often used to make paperboard, newsprint or sanitary paper. Newsprint is low-cost non-archival Paper most commonly used to print Newspapers plus other publications and advertising material Toilet paper is a soft paper product used to maintain Personal hygiene after human Defecation or Urination.

Bleaching

Main article: Bleaching of wood pulp

The pulp produced up to this point in the process can be bleached to produce a white paper product. Bleaching of wood pulp is the Chemical processing carried out on various types of Wood pulp to decrease the color of the pulp so that it becomes whiter Bleaching of wood pulp is the Chemical processing carried out on various types of Wood pulp to decrease the color of the pulp so that it becomes whiter A white paper is an authoritative report or guide that often addresses problems and how to solve them 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. Chlorine (ˈklɔriːn from the Greek word 'χλωρóς' ( khlôros, meaning 'pale green' is the Chemical element with Atomic number 17 and Chlorine dioxide is a Chemical compound with the formula ClO2 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the OZONE is an object oriented Operating system written in the C programming language. Hydrogen peroxide (H2O2 is a very pale blue liquid which appears colorless in a dilute solution slightly more Viscous than water

Environmental concerns

The major environmental impacts of producing wood pulp come from its impact on forest sources and from its waste products.

Forest resources

Main article: Logging

Main article: Plantations#Forestry

The impact of logging to provide the raw material for wood pulp is an area of intense debate. Logging is the process in which Trees are cut down for Forest management and Timber. Fundamentally a plantation is usually a large Farm or estate, especially in a tropical or semitropical country on which Cotton, Tobacco Modern logging practices, using forest management seeks to provide a reliable, renewable source of raw materials for pulp mills. Logging is the process in which Trees are cut down for Forest management and Timber. Forest management includes a range of human interventions that affect Forest Ecosystems. A pulp mill is a manufacturing facility that converts wood chips or other plant fiber source into a thick fiber board which can be shipped to a Paper mill for further The practice of clear cutting is a particularly sensitive issue since it is a very visible effect of logging. Clearcutting or clearfelling is a Forestry / Logging practice in which the clear majority of all trees in a forest sector are cut down Logging is the process in which Trees are cut down for Forest management and Timber. Reforestation, the planting of tree seedlings on logged areas, has also been criticized for decreasing biodiversity because reforested areas are monocultures. Reforestation is the restocking of existing forests and woodlands which have been depleted with native tree stock Biodiversity is the variation of Life forms within a given Ecosystem, Biome or for the entire Earth. Monoculture is the agricultural practice of producing or growing one single crop over a wide area Proponents of reforestation and plantations argue that in this respect trees are no different from any other agricultural crop. Fundamentally a plantation is usually a large Farm or estate, especially in a tropical or semitropical country on which Cotton, Tobacco Logging of old growth forests accounts for less than 10% of wood pulp^[6], but is one of the most controversial issues. Ancient Woodland Old growth forest, (also termed primary forest, ancient forest, virgin forest, primeval forest, frontier

Effluents from pulp mills

Pulp mills are almost always located near large bodies of water because of they require substantial quantities of water for their processes. Delignification of chemical pulps releases considerable amounts of organic material into the environment, particularly into rivers or lakes. The wastewater effluent can also be a major source of pollution, containing lignins from the trees, high biological oxygen demand (BOD) and dissolved organic carbon (DOC), along with alcohols, chlorates, heavy metals, and chelating agents. Biochemical Oxygen Demand or Biological Oxygen Demand (BOD is a chemical procedure for determining how fast biological organisms use up oxygen in a body of water Dissolved organic carbon (DOC is a broad classification for organic molecules of varied origin and composition within aquatic systems In Chemistry, an alcohol is any Organic compound in which a Hydroxyl group ( - O[[hydrogen H]]) is bound to a Carbon The chlorate anion has the formula ClO3− In this case the Chlorine atom is in the +5 Oxidation state. Chelation is the binding or complexation of a bi- or multidentate Ligand. Reducing the environmental impact of this effluent is accomplished by closing the loop and recycling the effluent (see black liquor) where possible, as well as employing less damaging agents in the pulping and bleaching processes. Black liquor is a Byproduct of the Kraft process, (also known as Kraft pulping or sulfate process) during the production of paper pulp

Mechanical pulp is not a major cause for environmental concern since most of the organic material is retained in the pulp, and the chemicals used (hydrogen peroxide and sodium dithionite) produce benign byproducts (water and sodium sulfate (finally), respectively). Hydrogen peroxide (H2O2 is a very pale blue liquid which appears colorless in a dilute solution slightly more Viscous than water Sodium dithionite (aka sodium hydrosulfite or sodium hydrosulphite is a white Crystalline powder with a weak Sulfurous odor Sodium sulfate is the Sodium salt of Sulfuric acid

Bleaching with chlorine produces large amounts of organochlorine compounds, including dioxins^[8]. Applications The simplest form of organochlorides are chlorinated Hydrocarbons These consist of simple Hydrocarbons in which one or more hydrogen atoms have Polychlorinated dibenzodioxins ( PCDD s or simply dioxins, are a group of Halogenated Organic compounds which are significant because they act Increased public awareness of environmental issues, as evidenced by the formation of organizations like Greenpeace, influenced the pulping industry and governments to address the release of these materials into the environment^[9] . Greenpeace, originally known as the Greenpeace Foundation, was founded in Vancouver, British Columbia, Canada in 1972 The amount of dioxin has been reduced dramatically by replacing some of all of the chlorine with chlorine dioxide^[10]. The use of elemental chlorine has declined significantly and as of 2005 was used to bleach 19-20% of all kraft pulp^[11]. EFC (elemental chlorine-free) pulping using chlorine dioxide is now the dominant technology worldwide (with the exception of Finland and Sweden where TCF is very important), accounting for 75% of bleached kraft pulp globally^[11]

Chemical pulp mills, especially kraft mills, are energy self-sufficient and very nearly closed cycle with respect to inorganic chemicals. Finland, officially the Republic of Finland ( is a Nordic country situated in the Fennoscandian region of northern Europe. "Sverige" redirects here For other uses see Sweden (disambiguation and Sverige (disambiguation.

Alternatives

Today, some people and groups advocate using field crop fiber or agricultural residues instead of wood fiber as being more sustainable. Fiber crops are field crops grown for their Fibers which are used to make Paper, Cloth, or Rope. Sustainability, in a general sense is the capacity to maintain a certain process or state indefinitely However, wood is also a renewable resource, with about 90% of pulp coming from plantations or reforested areas. ^[6] Non-wood fiber sources account for about 5-10% of global pulp production, for a variety of reasons, including seasonal availability, problems with chemical recovery, brightness of the pulp etc. ^[12][5]

Research is under way to develop biological pulping, similar to chemical pulping but using certain species of fungi that are able to break down the unwanted lignin, but not the cellulose fibres. A fungus (ˈfʌŋgəs is a eukaryotic Organism that is a member of the kingdom Fungi (ˈfʌndʒaɪ This could have major environmental benefits in reducing the pollution associated with chemical pulping. See also Nature The natural environment, commonly referred to simply as the environment, is a terminology that is comprised of all living and

See also

• Brittle Books Program
• De-inked pulp
• Paper pulp
• Pulp mill
• Pulpwood
• Wood-pulp paper

References

External links

• How pulp is made?

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