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The kraft process involves treatment of wood chips with a hot mixture of water, sodium hydroxide (NaOH), and sodium sulfide (Na 2 S), known as white liquor, that breaks the bonds that link lignin, hemicellulose, and cellulose. The technology entails several steps, both mechanical and chemical. It is the dominant method for producing paper.
The competing chemical pulping process, the sulfate or kraft process was developed by Carl F. Dahl in 1879 and the first kraft mill started (in Sweden) in 1890. [ 3 ] The first sulphite mill in the United States was the Richmond Paper Company in Rumford, Rhode Island in the mid-1880s.
Kraft paper or kraft[1] is paper or paperboard (cardboard) produced from chemical pulp produced in the kraft process. Sack kraft paper (or just sack paper) is a porous kraft paper with high elasticity and high tear resistance, designed for packaging products with high demands for strength and durability.
White liquor. White liquor is a strongly alkaline solution mainly of sodium hydroxide and sodium sulfide. It is used in the first stage of the Kraft process in which lignin and hemicellulose are separated from cellulose fiber for the production of pulp. [1] The white liquor breaks the bonds between lignin and cellulose.
Papermaking is the manufacture of paper and cardboard, which are used widely for printing, writing, and packaging, among many other purposes. Today almost all paper is made using industrial machinery, while handmade paper survives as a specialized craft and a medium for artistic expression. In papermaking, a dilute suspension consisting mostly ...
Paper chemicals designate a group of chemicals that are used for paper manufacturing, or modify the properties of paper. These chemicals can be used to alter the paper in many ways, including changing its color and brightness, or by increasing its strength and resistance to water. [1] The chemicals can be defined on basis of their usage in the process. Chemical usage is not only for imparting ...
Paper engineering is a branch of engineering that deals with the usage of physical science (e.g. chemistry and physics) and life sciences (e.g. biology and biochemistry) in conjunction with mathematics as applied to the converting of raw materials into useful paper products and co-products. [1] The field applies various principles in process engineering and unit operations to the manufacture ...
Black liquor. In industrial chemistry, black liquor is the by-product from the kraft process when digesting pulpwood into paper pulp removing lignin, hemicelluloses and other extractives from the wood to free the cellulose fibers. [1] The equivalent material in the sulfite process is usually called brown liquor, but the terms red liquor, thick ...