7 Solvent Extraction Process for Recovery of Americium-241atHanford P. C. DOTO, L . E . BRUNS, and W. W. SCHULZ
Downloaded by CORNELL UNIV on November 12, 2012 | http://pubs.acs.org Publication Date: July 20, 1981 | doi: 10.1021/bk-1981-0161.ch007
Rockwell Hanford Operations, Richland, WA 99352
Solvent e x t r a c t i o n [ t r i b u t y l phosphate (TBP)] operations t o recover plutonium from u n i r r a d i a t e d scrap have been performed at the Hanford S i t e s i n c e 1955. The aqueous r a f f i n a t e (CAW stream) from the TBP plutonium e x t r a c t i o n process c o n t a i n s , t y p i c a l l y , Mg+2
>
]
approximate
n i t r a t e s
1.7
2
are m o l a r i t i e s .
n i t r a t e
v o l % DBBP-xylene A l
2 +
DBBP
from
10 was
[ M g
f a i r l y
constant
+
1— [H+]
4
concentrations
t i o n
10"
j
Am
other
5 . 5 χ
j
6
when
addition
of
NaOH. Proper is
c r u c i a l
cium. i t y to
adjustment to
Kings!ey's(7)
must
be a d j u s t e d
achieve
Proper trated
adequate
adjustment
v i o u s l y
requires NaOH
to
to
careful
with
of
americium
NaOH
f o r
extract
solutions
leaves,
and from of
s i b l e
use d i l u t e
to
p a r t i t i o n
o f
Am
within of
a c i d i t y
of
ameri-
show in
that
t h e CAW
range
the
this
of
Over-addition
excess
HNO3
to
ob-
concen-
of
a c t i n i d e s
and separation.
course,
phase. range
addition
scavenge
a c i d -
0.1-0.3M
DBBP
narrow
in-line
which
t r ivalent
the
to
3 +
s o l u t i o n .
have
exceedingly
metal
f o r
americium
of
d i s p e r s i o n
and others
a f f i n i t y
3)
CAW s o l u t i o n
NaOH
and
i n t e r -
I n s u f f i c i e n t compete
with
extractant.
Pu(IV)
DBBP
control
solids
phase
DBBP
Siddall(8) tions
(Figure
unbuffered
fere
of
extraction
concentration
CAW a c i d i t y
hydroxide
a d d i t i o n
a
d i s t r i b u t i o n
of
an
DBBP
r e s u l t s
p r e c i p i t a t e s greatly
(neutralization)
s a t i s f a c t o r y
well
n i t r a t e - l o w
Pu(IV)
over
(0.1-0.25M) from
observed
that HNO3
co-extracted
that
from HNO3
DBBP-diluent
both
strong
s o l u t i o n s .
f o r Am(III) solutions
to
plutonium.
s o l u -
HNO3 The
makes
it
greater pos-
s e l e c t i v e l y The
r e s u l t i n g
In Transplutonium Elements—Production and Recovery; Navratil, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.
116
TRANSPLUTONIUM
acid
s t r i p
cation 2 1 f l
s o l u t i o n
exchange
Am.
from
s o l u t i o n . recycled
to
The of
the
DBBP
f o r
Downloaded by CORNELL UNIV on November 12, 2012 | http://pubs.acs.org Publication Date: July 20, 1981 | doi: 10.1021/bk-1981-0161.ch007
Fe3+,
into
the
iron
cal
flowsheet
and
ure
process 4
previous
subsequent
a
of
the
e f f e c t i v e l y d i l u t e
c a n be
of
HNO3-HF
conveniently
the mainline
2 +
,
e x c e l l e n t the
and M g of
of
HNO3 of
provides from
PRF
TBP
aluminum,
s t r i p
the
range
Flowsheet. of
operated,
in
of
S i g n i f i c a n t
factors
103
-
4
from
of
the
the
and
80-180
t y p i c a l
chemi
countercurrent the
minor
values
s i x
years
changes c i t e d
used.
operations
in
aluminum.
the in
of
accompany
recovery
range
Over
generally
A m
f o r
5
n a t u r a l l y ,
those
Richardson(9_)
features
the
10
CAW s o l u t i o n .
p l a n t - s c a l e
and
because
Richardson(9j
Hanford
but
DBBP-CCI4
sodium 2 4 1
the
0.025,
p a r t l y
DBBP
in χ
v o l %
and
i l l u s t r a t e s
were,
of
1.5
at
and f l o w r a t e s ,
employed
r e s u l t s
χ
there
representative
i r o n ,
s o l u t i o n .
employed
Am
2 I f l
2
30
in
d i s t r i b u t i o n
