Tissue360 - Spring/Summer 2016 - (Page 6)
New Look at an
Old Recycling Technology
An article that begins on page
14 (and is featured on the cover of this
issue) takes an in-depth look at kneading technology as a promising new
approach for deinking wastepaper to be
used in making various grades of tissue
and toweling. Kneading is not really a
new technology. It has been around for
years and is in limited commercial use
globally, though not so much if at all
in North America - at least not yet.
Printing and writing (P&W) papers have been and still are the
main source of quality wastepaper for making tissue. But with the
rise of digital communications in recent years, P&W production has
declined significantly, and quantities of graphic papers have fallen in
the recycling stream, creating the first stages of a potential tissue fiber
crunch that could impact certain away-from-home markets in the not
too distant future, especially in North America where most AfH tissue
grades are made with recycled P&W paper fiber.
In addition to improving both the quality and yield of recycled
furnishes, the kneading process, especially when combined with
advanced "vertical washing" technology as described in the article,
also has a particularly attractive environmental/sustainability side.
With the type of kneader-based recycling operation that Hiroki Nanko
of Insight Technology International LLC has set up in his pilot plant
operation in Macon, Ga., wastepaper can be very effectively deinked
without any chemistry at all, and with attractive yield increases.
In Nanko's Taizen (Japan) kneader pilot plant, recycled fibers go
through a gentle but intensive rubbing motion for a long time (about
10 min), without the use of any deinking chemicals. Friction between
the fibers breaks almost all of the fiber-ink bonds, resulting in very
small ink particles that are more easily removed in the subsequent
vertical washer stage. The flotation deinking process, by comparison,
is only efficient for ink particles larger than 10μm.
KEN PATRICK, Editorial Director/Associate Publisher
LARRY N. MONTAGUE, President & CEO, TAPPI
ERIC FLETTY, VP Operations, TAPPI
JAN BOTTIGLIERI, Editorial Director, Paper360o
MONICA SHAW, Editorial Director, TAPPI Journal
spring/ summEr 2016
In the subsequent washing stage, not only the detached ink, but
also the ash (fillers and coatings) and fines must be removed. For tissue grades, low ash content is a basic requirement since it interferes
with fiber-to-fiber bonding and slows drainage. Fines also need to be
removed to improve drainage on the tissue machine. Other technologies such as the DNT washer can achieve this, but cause significant
fiber loss in the process. The vertical washer can remove ink, ash and
fines without losing long fibers, according to Nanko,
Kneader-based technologies can also be used to pulp non-wood,
alternative fibers for tissue production. At the TAPPI Tissue Forum
at PaperCon, May 16-18, 2016, in Cincinnati, Ohio, USA, Nanko will
examine kneader technologies for processing alternative fibers for
tissue and towel production. His presentation is set for Session TF2
from 3:30-5:00 p.m. on May 16.
In his presentation, Nanko looks at a new Alkaline Peroxide
Mechanical Pulping (APMP) system based on kneader technology that is proving to be highly effective with non-wood fibers.
A wide variety of non-wood plant materials can be pulped with
the APMA process, including wheat straw, rice straw, bagasse,
bamboo, kenaf, Arundo donax, Miscanthus, switch grass, flax,
oil palm EFB, etc.
Non-wood fiber is pulped in the Taizen kneader, in the presence
of frictional heat, that softens the lamella lignin between fibers.
Chemicals, typically 3 percent NaOH, are added in the kneader,
allowing the fibers to be very effectively separated. H 2O2 also can
be added to make the pulp whiter when it exits the kneader. Gentle
chemi-mechanical treatment of the Taizen system keeps the fibers
long with no "cutting," so that the pulp produced is suitable for
Editorial Director/Associate Publisher, Tissue360o.
Table of Contents for the Digital Edition of Tissue360 - Spring/Summer 2016
Tissue Industry News
Focus on Global Tissue Key Move for Buckman
Bamboo Tissue Mill Nears Startup in China
2016 Edition of TAPPI Tissue360o
Bright New Star in the Global Tissue Industry
Tissue360 - Spring/Summer 2016