HEFT AND KAHN
The original ashed filter sample is divided into
five portions. One of these is mounted directly on
a Millipore filter as a postashing control sample,
and the remaining four are used to prepare Sets of
particle-fraction samples by sedimentation. The
number of sedimentation runs per original sample
is dictated partly by the variety of subSequent analysis requirements and partly by the need to know
how the sedimentation-rate distribution varies with
the density of the sedimentation fluid. Briefly, the
particle~separation experimental procedure is as
follows:
JD)
a
7a
I, V3
AY
AY
YZ
1. The weighed, ashed particle sample is suspended in a known volume of isobuty! alcohol. The
volume used is determined by the requirementthat
the particle volume should not exceed 0.5% of the
isobutyl alcohol volume.
2. Three 25% aliquots of the suspension are
taken for sedimentation and mounted filter-sample
preparation. One 5% aliquot is taken for sedimenFig. 2—Centrifugal
sedimentation tube.
PREASHING
CONTROL
tation preparation of a set of particle samples sus-
PC
FILTER
°
O = MILLIPORE FILTER
X% = LIQUID SUSPENSION
{
LOW-TEMPERATURE ASHING
PARTICLE
SUSPENSION
ISOBUTYL ALCOHOL
POSTASHING
CONTROL
PARTICLE
FRACTIONS
!
Zz
!
CARBON
CHLOROBENZENE
TETRACHLORIDE SEDIMENTATION
SEDIMENTATION
00000
00000
RADIOCHEMICAL
ANALYSIS
4
N-BUTYL
ALCOHOL
SEDIMENTATION
N-BUTYL
ALCOHOL
SEDIMENTATION
00000
00000
00000:
00000
XXXXX
XXXXX
NEUTRON
NONDESTRUCTIVE
MICROSCOPY
ACTIVATION
ANALYSIS
ANALYSIS
X RAY
ELECTRON
PROBE
Fig. 3—Analysis flow diagram.
Sf