Jessica North wrote:
> I understand that paper fibres can be recycled 6-7 times, after which
> they are too reduced in length to produce a paper product. Since paper
> to be recycled is collected together, regardless of whether it is from
> virgin origin, 2nd time recycled, 6th time recycled, etc., what
> happens to the paper fibres that can no longer be recycled? If they
> are somehow removed during the recycling process, what is their fate?
> And finally, does this mean that there will always be a need for a
> "rejuvenating" stock of virgin product?
There is no magic number about the number of times you can recycle fiber. Much depends on the fiber you start with and the product you are trying to make. Some of the longest and strongest fibers can be found in corrugated boxes. This type of paper is produced through what is called the kraft process ---- the envnin bonds holding the fibers are dissolved, allowing the fiber to separate without much damage. On the other hand, the fiber in newsprint, or any groundwood fiber is relatively short --- groundwood means exactly that, the wood is mechanically ground into a pulp. The fibers take quite a beating.
If you are making recycled liner for a corrugated box, you want to start with a high quality recovered fiber, like a corrugated box. But fiber that may be too short or weak for making a corrugated box can be used for another product, like recycled paperboard. In the same manner, recycled fiber from newsprint can find its way back into newsprint, or it can go into recycled paperboard and end up as part of a cereal box when mixed with other fibers. You could never use newsprint to make a corrugated box – it would wash out as sludge.
In the end, short weak fibers that end up at recycling mill will be separated out in the filtering equipment and end up with the sludge, but how many times it goes through is a factor of what you started with and what you are making. Sludge is sometimes burned as fuel, but I believe most is landfilled. The amount of sludge varies widely with the type of paper being produced. If the paper needs to be deinked there is significantly more sludge than if it isn’t deinked.
Shrinkage in the recycling process is only one of the reasons
that as long as we continue to use paper, we will need a continued infusion of stronger,
longer virgin fibers into the process.
More importantly, we need an infusion of fresh fiber because a
significant volume of paper is not recoverable as a result of contamination or
end use. Paper used in a medical setting
or used as packaging for hazardous chemicals, for example, should not be
collected for recycling and paper that goes into permanent applications like
wallboard facing, furniture components, books, automobiles, etc. cannot be
recovered. Last time I did the
calculations, close to 20 or 25 percent of paper consumed in the
Hope this helps answer your question