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Recovery of Rare Earth and Cobalt from
Co-based Magnetic Scraps
Xu
Tao
1,2
, Zhang Xiao-
dong
3
(1 Baotou
Research Institute of Rare Earth , Baotou
014030,China
2 National
Engineering Research Center of Rare Earth
Metallurgy and
Functional
Materials,Baotou 014030,China
3 Inner Mongolia Baotou Steel Rare
Earth Hi-Tech CO., LTD., Baotou
014030,China)
Abstract:
The reuse of RE
and cobalt in Co-based magnetic scraps was
studied. Making sure feat lixiviated
condition is that: 200 mesh,
sulfuric
acid
dosage
of
1.4
ti
mes
theoretic
dosage,
temperature
90℃,
leaching time 1h. The result indicated
that lixiviate rate of cobalt
and
rare
earth
attained
97.8%,
99.6%
respectively.
The
optimum
technology conditions was:Na
2
S
2
O
8<
/p>
dosage of 8 times theoretic dosage,
oxidation
tempe
rature
80℃
,
oxidation
time
2
hour,
pH=
earth
was
precipitated by saturated (NH
4
)
2
C
2
O
4
solution, after roasting
of
rare
earth
oxalate,
received
rare
earth
oxide.
The
samarium
and
gadolinium
sum
recovery
was
96%,
92%
respectively.
Cobalt-iron
residue
was
soaked
by
hydrochloric
acid,
the
Fe(OH)
3
was
preferential
solution, pH was adjusted to 1.4 by
hydrochloric acid, Co(OH)
3
does
not dissolved, Cobalt
and iron were separated, after roasting of
Co(OH)
3
,received
cobalt
oxide.
The
total
recovery
of
cobalt
was
found
to be 97% and rare earths was
96%.
Keywords:
cobalt-based magnetic scrap; cobalt;
rare earth
CLC number:
TE992.3 Document code: A
SmCo alloy was 70 years of the 20th
century developed a new type of
permanent magnetic materials, because
of its high Curie temperature,
资料内容仅供您学
习参考，如有不当或者侵权，请联系改正或者删除。
temperature
stability,
corrosion
resistance
and
good
oxidation
resistance,
the
advantages
of
the
permanent
magnet
material
has
an
irreplaceable
role,
so
since
the
advent
of
SmCo
permanent
magnet
get
wide
attention.
The
material
in
microwave
communication
technology,
audio-visual
technology,
electrical
engineering,
instrumentation
technology,
computing
technology,
automation
technology,
transportation,
petrochemicals, magnetic technology,
magnetic separation technology,
biological
engineering
and
magnetic
fields
of
medical
and
fitness
equipment is widely used The materials
have already become an important
material
foundation
of
new
technologies
[1]
.
Permanent
magnet
material
in
the
molding process, 20 to 30%
of scrap
material and discarded as waste,
extraction of cobalt and rare earth,
can recycling
[2 ~ 6]
. By
extraction
and precipitation
[7]
The rare earth permanent magnet
rare earth elements
in
industrial
waste
recycling
and
cobalt
have
been
reported,
Zhang
[8]
Xiaodong
and
others
The
cobalt-based
alloy
material
waste
comprehensive
utilization of
resources were reviewed, studied co-based magnetic
scrap
leaching
conditions
and
recovery
of
rare
earth
oxide
and
cobalt
separation
process
conditions.
1
Experimental
1.1 Materials
and instrument
Cobalt-based
magnetic
scrap
was
the
main
material
used
in
this
experiment.
And
experimental
water
are
deionized
water,
all
reagents
were
of analytical grade.
ICP-AES (US Varian, Inc)
1.2 Experimental methods
1.2.1 Elements of the leaching
experiment
Table 1 Chemical
composition of the SmCo magnetic scraps
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(mass fraction, %)
Element
Content
Sm
21.62
Co
49.80
Fe
16.04
Gd
4.34
Accurately
weighed
20g
sample
dissolved
with
2m
oLH
2
SO
4
,
impact
of
sample
on
leaching
of
elements
in
the
main
factors
size,
amount
of
sulfuric
acid,
temperature and time of each
experiment.
1.2.2 Oxidation
of cobalt and iron to precipitate into purpose and
RE
separation
Take
100mL
the
leaching
solution
into
the
500mL
beaker,
Co
2+
and
Fe
2+
were
oxidized to
Co
3+
and
Fe
3+
with Na
2
S
2
O
8
in leaching solution, to be obtained
Co(OH)
3
and
Fe(OH)
3
. After filtration,
rare earth
、
cobalt and iron
separation.
Cobalt
and
iron
in
solution
and
precipitation
were
analyzed,
in
order
to
express
the
rate
of
precipitation
of
cobalt
and
iron,
and
the
separation
between
the
three
metals.
Addition
of
ammonium
oxalate
in
the
filtrate
after
precipitation
of
rare
earth,
precipitation
after
washing,
drying and roasting
were rare earth oxides.
1.2.3 Separation of cobalt and
iron
The
precipitation
of
Co(OH)
3
and
Fe(OH)
3
were
dissolved
in
hydrochloric
acid(1moL),then
control
pH<3.5,Fe(OH)
3
priority
dissolved;
nevertheless,
the
precipitation
of
Co(OH)
3
was
not
dissolved
when
pH>1.4
to
be
separated
cobalt and iron.
1.2.4 Detection of elements
The element was determinated by
volumetric method, gravimetric method
and ICP-AES.
2
Results and analysis
2.1
Leaching test results and discussion
2.1.1 Size on leaching rate