Newsprint

Origins

Charles Fenerty of Halifax, Nova Scotia, is generally credited with making the first newsprint paper from wood fiber in 1838. He had been hired by a local paper mill to maintain an adequate supply of cotton and linen rags (then used to make paper), but could not supply enough used and discarded clothing in such a thinly populated region. Experimenting with materials, Fenerty discovered a process of grinding softwood waste from lumber mills that kept the long fibers in the wood intact. The resultant wood fiber was found to be a suitable substitute for the cotton or linen (flax) fibers previously used to make paper.

A German engineer, F. G. Keller, developed specialized mechanical pulping machinery in the 1840s. Chemical methods of extracting the wood fiber quickly followed, first with Englishman James Roth's use of sulfurous acid to break down wood, followed by Philadelphia chemist Benjamin C. Tilghman's 1867 American patent on the use of calcium bisulfate to pulp wood. Tilghman's process involved heating a mix of wood chips, water, and chemicals to separate the fibers. Almost a decade later, the first commercial sulfite pulp mill began operation in Sweden. By 1900, the chemical pulping of softwoods such as pine had become the primary method of producing newsprint, although mechanical pulping plants continued in operation.

The alternative chemical pulping approach using sodium sulfate, the kraft process, was developed by German inventor Carl Dahl in 1879 and the first kraft mill opened in 1885 in Sweden. The resulting paper pulp was much stronger and more durable than previously, and hence the process was termed “kraft” (German for “strength”). Although the kraft process creates a brown paper (used for cardboard, bags, wrapping paper, etc.), bleaching it makes newsprint. The invention of the recovery boiler in 1930 by American engineer George Tomlinson allowed kraft mills to recycle almost all of their pulping chemicals, a significant cost savings. This, along with the ability of the kraft process to treat a wider variety of wood types and produce stronger fibers, made it the dominant pulping process by the late 1940s.

Pulp used in manufacturing newsprint at the Southland Paper mill in Lufkin, Texas, around 1943.

Source: Library of Congress.

Making Newsprint

Although simplified and improved by the coming of steam power (as early as 1857 Swedish mills were using steam-driven grinders and refiners) and later electricity (beginning in 1902 at the Hudson River Mill in New York state), Fenerty's process remains the basis for making newsprint. New-growth trees raised specifically for pulp or waste timber is debarked and ground into wood chips. These then pass through a digester (for chemical pulping) or refiner (mechanical pulping) that separates the wood fibers from the rest of the cellulose. The fibers are combined with large quantities of water, creating a pulp mixture (about the consistency of oatmeal). Passing over screens and mesh belts, water is drained away to leave a wet fiber mat. Finally, the fiber mat is fed into presses; the fibers bond as the last of the water is squeezed out. Drying is completed with steam heat, and the result is a low-grade paper suitable for a variety of uses.

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