郑州大学研究生毕业论文
Abstract
The shortage of
material
for paper
making
will last for
years.Non-wood
fiber
especially wheat straw will be
important
component
of materials
for paper
making.
Steam
explosion
pulping
is
a
new kind
ofmethod
for pulp
making,witll
its
lligh
yield'
good physical properties,low energy
consumption
and low
pollution
discharges.But
the
low level ofbrightness
limit
its usage.Few researchers focus
their
eyesight
on
the
bleaching
of wheat straw pulp.In this
paper,the
bleachablity of exploded pulp
from
wheat straw was
studied.
The
research
showed that exploded pulp could
be
bleached
witll
OQP
bleaching.
Through
the study
of
bleaching
on
wheat sll-aw,it
was
found
that oxygen
delignification
conditions,namely
pulp
consistency 5%,NaOH
charge
14%,MgS04
O.5%,02
pressure
O.8MPa,140℃and
2
hours,resulted
in
better
effect
of
delignification
and
small
loss offiber.
The
Optimal
process conditions of H202
bleaching are-consistency
10%,HE02
3%,Na2Si03
3%,MgS04
0.5%,the
brightness
reached
30%SBD.
Pressurized/high
temperature
peroxide bleaching ofwheat straw pulp was carried
out,The
optimal
process
conditions
of H202
bleaching
are:consistency
10%,H202
3%,Na2Si03 3%,MgS04 O.5%,the
brightness
reached
30%SBD.The
research
showed that the effect of
transition
metal
ions
on
hydrogen
peroxide
bleaching
of
non-wood
pulps was notable.Pretreatment
to
decrease
the
contents
of Cu2+and
Mn2+
is
unavoidable.The
mechanism
ofaction is
studied.
Key words:wheat
straw,steam
explosion pulp,oxygen delignification,hydrogen
peroxide,OQP
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