Paper is Made from What?!

Adam Gendell

Ask yourself “what is paper made from?” and let me guess your answer to this seemingly rhetorical question: trees. Easy, right? Paper is made from trees. The input to the papermaking process is trees, and the output is paper.

If only it were that simple. Paper is certainly made from trees (or other fibrous plants), but there is a whole slew of other materials that paper is “made” from. Let’s look at the kraft pulping process, which is the first step used to make the majority of paper packaging. The trees are harvested, chipped, and put in a solution called “white liquor,” which is a mixture of water, sodium sulfide, and caustic soda. Your answer to our seemingly rhetorical question has already become more educated: paper is made from trees, water, sodium sulfide, and caustic soda.

Let’s keep going. Caustic soda is produced by running electricity through salt water. Interestingly, the salt water is created by adding fresh water to salt that was produced by evaporating naturally occurring salt water, instead of using the naturally occurring salt water itself, which has too many other types of dissolved solids. Where does the sodium sulfide come from? Most of it is made by mixing ground up coal with a substance known as “salt cake.” And where does salt cake come from? About two thirds of salt cake is harvested as the mineral mirabilite, and the remainder is produced as a byproduct of hydrochloric acid production.

If the paper is white, then it’s probably been treated with chlorine (also made from running electricity through salt water), chlorine dioxide, or an alternative combination of ozone (made from running electricity through air) and hydrogen peroxide (don’t even ask how hydrogen peroxide is made. I looked it up, and found phrases like “autoxidation of a 2-alkyl anthrahydroquinone”).

Modern papermaking is a fascinating process and decades of innovations have resulted in every single input being used to its fullest extent with a minimized amount of non-paper outputs. The white liquor is recycled inside a paper mill, using lime (calcium oxide, made from limestone) and small amounts of new white liquor to reconstitute its needed properties. By amount used, trees vastly outweigh every other resource used to make paper. Nonetheless, it’s important not to oversimplify the answer to my seemingly rhetorical question.

So what is paper made from? Trees, water, salt water, coal, mirabilite, limestone, maybe 2-alkyl anthrahydroquinone. It might contain calcium carbonate (more limestone), kaolinite (clay), talc, or titanium dioxide as a filler. Perhaps a wax emulsion is used as a sizing agent. Formaldehyde could be added to improve its strength when wetted. Some paper is treated with optical brighteners, dyes, pitch control chemicals, and slimicides. It might still suffice to say that paper is made from trees, but sustainability is complicated and we shouldn’t oversimplify our concept of paper production to the point where we think that the only inputs are trees. It’s important to keep in mind that paper as we know, as well as all products, couldn’t be made without a fascinating array of other additions.

7 Responses to Paper is Made from What?!

  1. stonepapersales@gmail.com says:

    Dear Adam,

    You need to make a clarification/correction to the statement that the (The white liquor is “recycled”) it can not even be called “post industrial recycled”. Per the FTC: In plant recycling does not qualify for claiming a portion an item is “recycled” unless it leaves the plant and is rescued from a waste stream. It is deceptive to misrepresent, directly or by implication, that a product or package is made of recycled material, which includes recycled raw material, as well as used,(5) reconditioned and remanufactured components. Unqualified claims of recycled content may be made if the entire product or package, excluding minor, incidental components, is made from recycled material. For products or packages that are only partially made of recycled material, a recycled claim should be adequately qualified to avoid consumer deception about the amount, by weight, of recycled content in the finished product or package.

    I realize you were just trying to highlight that they use every bit in the process as not to waste but the word recycled is not an accurate description.

    • Adam Gendell says:

      Thanks for your comment. The cadre of “R” words that we use to describe sustainability attributes is large and growing, and I agree with you that it is imperative that we use them correctly. In this instance, “recirculated” would have been the more appropriate word. It would certainly be dismaying (and most certainly confusing to the general public) if we were to see paper products that had claims saying “made with recycled liquor”!

      • Gary says:

        I think recycled is the correct word. According to the FTC you could not label the resulting product as being made with recycled material, but according to Merriam-Webster the definition of Recycle 1c: “to reuse or make available for reuse…”.
        Since the liquor is enhanced and reused, it is being recycled, but not to the level to satisfy government advertising standards.


  2. amos miller says:

    thanks it helped

  3. Kira says:

    i am doing a report on paper for my ela class and i dont know anything about it so here are my questions…
    Where was paper made?
    Who made paper?
    When was paper made?
    How do you make paper?

  4. Luke says:

    Hm, so, how about other paper making processes and materials? Wood based paper is not the only paper available and is definitely not the only primary source or the best. Could you talk about alternatives to wood based papers?

    • Chris Maple says:

      The best quality papers are not made from trees (wood) at all. They are made from cotton rags, after bleaching, and from esparto grass. Both of these are high in cellulose which is the essential ingredient in paper. Paper made from these products is very expensive and is not used for newsprint or for paperback books.

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