What is Pulp?
Pulp is wood that is prepared for making paper. There is a manufacturing process required to create paper from this pulp (Committee on Industrial Environmental Performance Metrics, 1999, p. 129). There are six different types of pulp.These types are seperated into four categories. These categories are mechanical, semi chemical, chemical, and deinked pulp. Mechanical pulp has two types of pulp. These types are stone groundwood pulp and thermo-mechanical pulp. These types of pulps are used for newsprint and lightweighted coated paper for calendars. Semi-chemical pulp has one type of pulp called semi-chemical pulp. This type of pulp is used for tissues. Chemical pulp has two types of pulp, sulphite and kraft pulp. Sulphite pulp is used for newsprint, printing paper, writing paper, tissue, and sanitary paper. Kraft pulp is used for graphic paper, tissue, carton board, wrapping paper, bags, and envelopes. De-inked pulp is pulp that has been recylced, when inks and other containments have been removed (European Paper & Packaging Industries).
Manufacturing Process
There are five main steps of manufacturing all pulp and paper. These steps include material preparation, pulp manufacturing, pulp bleaching, paper manufacturing, and fiber recycling (World Bank Group, 1998).
The manufacturing process takes place in a pulp mill. The first step of pulp manufacturing is material preparation. This is debarking and chipping the wood in preparation of manufacturing (World Bank Group, 1998).
The second step is pulp manufacturing the actual manufacturing of the pulp. This is done by using a cheminal, mechanical, and semi-chemical method (World Bank Group, 1998). The chemical method creates a chemical pulp such as sulphite pulp and kraft pulp. Sulphite pulp is produced by cooking the wood chips in a pressure vessel with bisulphite liquor. Kraft pulp is produced by cooking the wood chips in a pressure vessel with sodium hydroxide liquor. Mechanical method produces groundwood and thermo-mechanical pulp. Groundwood pulp is produced by mechnically grinding wood into short fibres. Thermo-mechanical pulp is produced by softening the wood particles in steam before entering a pressure refiner. Semi-chemical pulp is produced by chemically treating the wood particles before the wood particles enter a refiner (European Paper & Packaging Industries).
The third step of the pulp manufacturing is pulp bleaching. This is done by using a chlorine free method (World Bank Group, 1998).
The fourth step of pulp manufacturing is paper manufacturing. The pulp will be either manufactured in the mill for paper or be shipped to a different mill for creation of paper and cardboard. Water is removed and chemicals are added to the paper (World Bank Group, 1998).
The final step of manufacturing pulp and paper is fiber recycling (World Bank Group, 1998).
History of the Industry
In Canada, pulp and paper was an increasing industry until the 2000s then it became a decreasing industry. The pulp and paper industry hit its peak in production during the 1990s. This industry has been decreasing because there is less of a need for paper in the world (Bogdanski, 2014).
Currently, there is seventy nine million tons of paper is produced in the United States , making up sixty five millions tons which is thirty six percent of the United States timber harvest yearly. The process of grinding and pulping wood to create paper started being developed during the 1850s in the United States and Europe. Since the 1900s removal of wood has been increasing in the United States but the amount of forest and number of trees has been increasing. Currently there is twice as much wood than what is harvested (Bowyer, Howe, Pepke, Bratkovich, Frank, & Fernholz, 2014).
References
Bogdanski, B. E. (2014, November/December). The rise and fall of the Canadian pulp and paper sector. Retrieved from http://pubs.cif-ifc.org/doi/pdf/10.5558/tfc2014-151
Bowyer, J., Howe, J., Pepke, E., Bratkovich, S., Frank, M., & Fernholz, K. (2014, July 9). Tree-free paper: a path to saving trees and forests? Retrieved from http://www.dovetailinc.org/report_pdfs/2014/dovetailtreefree0714.pdf
Committee on Industrial Environmental Performance Metrics. (1999). Industrial Environmental Performance Metrics. Washington, DC: National Academy of Sciences.
European Paper & Packaging Industries. (n.d.). Pulp Varieties. Retrieved from http://www.paperonline.org/paper-making/paper-production/pulping/pulp-varieties
World Bank Group. (1998, July). Pulp and Paper Mills. Retrieved from https://web.archive.org/web/20090306124028/http://www.ifc.org/ifcext/enviro.nsf/AttachmentsByTitle/gui_pulp_WB/$FILE/pulp_PPAH.pdf