β Scribed by Merle B. Shaw; George W. Bicking
No coin nor oath required. For personal study only.
THERE are approximately from 200,000 to 300,000 tons of clay used annually in the paper industry of the United States. Considering that the larger portion of this amount is of foreign source and that the clay resources of the United States are to a great extent undeveloped, the investigation herein reported was made to ascertain the relative merits of American and foreign clays for use as paper fillers.
The term " clay " is applied to a variety of earthy substances, differing widely in their origin and composition in many of their physical properties.
The essential requirements of a papermaking clay are : Good color; low content of grit, mica, and other impurities; and uniformity.
The first requirement must be possessed by the clay in its original state, but the percentage of impurities, such as grit and mica, can be lowered by washing and separation.
The paper section of the Bureau of Standards is equipped for making paper in a semi-commercial way and under practical mill conditions.
The experimental paper-making equipment available for the work on clays consisted of a fifty-pound wood tub beater with manganese-bronze bars and plate, a small Jordan with iron bars, a four-plate screen, and a twenty-nine-inch Fourdrinier machine with wire thirty-three feet long and having two presses, nine fifteen-inch dryers, a small machine stack of seven rolls, and a reel.
Commercial soda and sulphite pulps, and eight representative clays, five American and three foreign, were used in this investigation.
Preliminary runs established best method of handling clay and determined constant factors.
The comparative study included tests for the amount of clay retained in the paper, the quality of the paper produced, and those physical properties of the clay (grit, etc.) that might affect the paper-manufacturing processes. Measurements for clay retention included analyses of samples taken at thirteen different positions 8 Technologic
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