152 Nuclear Forensic Analysis
Th reaction product. If an application requires particularly pure Th metal, ZnCl
2
can
b
e
us
ed
a
s
t
he
b
ooster.
Z
n
0
and Th
0
form a low-melting alloy of biscuit metal, from
w
hich
Z
n
0
can be distilled, leaving only approximately 100 ppm in the Th. Also,
t
he
C
aCl
2
reaction product acts as a ux with the CaF
2
slag, giving a better phase
s
eparation
f
ollowing
t
he
r
eaction.
T
horium
me
tal
ca
n
a
s
w
ell
b
e
p
roduced
i
n
a
b
omb
r
eduction of ThCl
4
with Na
0
, under an inert atmosphere.
As
w
ith
U
,
p
owdered
T
h
me
tal
ca
n
b
e
p
roduced
i
n
t
he
r
eaction
o
f
C
a
0
with ThO
2
.
T
he
r
eaction
i
s
us
ually
p
erformed
i
n
a
N
i
b
oat
u
nder
a
H
2
atmosphere to prevent pre-
mature
i
gnition.
T
his
r
eaction
i
s
a
lso
e
xothermic,
b
ut
i
s
n
ot
s
ufcient
t
o
f
orm
a
m
ol ...