How to Calculate Pulp Density

••• grunge paper pale paper image by Andrew Brown from Fotolia.com

Pulp refers to the slurry of fibrous plant matter produced by a number of distinct manufacturing processes that render plant material chemically or mechanically. Many pulp producers sell dried sheets as a commodity for other manufacturers to purchase and convert into paper. In 2005 the global pulp market consisted of 54.3 million tons sold internationally. The density of pulp determines the weight of paper produced from the pulp. Retailers purchase and sell paper based on its weight per ream. Pulp density ultimately determines the quality of paper that pulp can produce.

    Pour 10 liters of water into an empty, transparent container. Mark along the outside of the container at the waterline. Label that line as 10 liters.

    Drain the water from the container. Allow the container to dry completely. Weigh the dry container and record its base weight.

    Fill the container with the pulp slurry up to the 10 liter mark. Weigh the filled container and record its total weight with the slurry. Subtract the total weight of the container with the slurry from the container’s base weight. The difference between the two provides the total weight of the slurry.

    Dry the pulp in the container. Allow the pulp to air dry, ensuring that none of the fibrous material is lost during the drying process. Weigh the container with the dried pulp once all moisture has evaporated. Record the total weight and subtract the base weight of the container. The difference between the two provides the weight of the dry pulp.

    Calculate the pulp density in terms of composition. Divide the weight of the dry pulp by the total weight of the slurry and multiply by 100. The product is the slurry concentration by weight, which shows the percentage of the slurry that is composed of dry pulp. For example, if the total weight of the slurry is 240 kilograms and its dry weight is 84 kilograms, dividing 84 by 240 and multiply by 100 which equals 35 percent.

    Determine the pulp density in terms of weight per volume by dividing the total weight of the slurry by its volume. Since you measured the total weight of 10 liters of slurry, divide the total weight by .01 cubic meters since one liter equals .001 cubic meters. For example, if the total weight of the slurry was 240 kilograms its density in weight per volume is 24,000 kilograms per cubic meter.

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About the Author

Sean Butner has been writing news articles, blog entries and feature pieces since 2005. His articles have appeared on the cover of "The Richland Sandstorm" and "The Palimpsest Files." He is completing graduate coursework in accounting through Texas A&M University-Commerce. He currently advises families on their insurance and financial planning needs.

Photo Credits

  • grunge paper pale paper image by Andrew Brown from Fotolia.com

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