USAC has a
comprehensive quality control program for the production of antimony
oxide. The control program includes (1) carefully sourcing raw
materials with low impurities, (2) the campaigning of single lots
with no commingling of other lots, (3) the dedication of one
production line for one product, (4) the removal of impurities, (5)
the careful adjustment of production controls, (6) the detailed
monitoring of product for color, size, impurities, content, and
other physical, mineralogical, and chemical parameters, (7) careful
labeling of all products, (8) packaging, and (9) a statistical
product control system (SPC). Composite samples for each lot are
kept in a library for
A Fisher Sub-Sieve
Sizer (FSSS) is used in the plant for the control of the median
particle size. A Micromeritics Sedigraph is used for particle size
distribution. Color determinations are made using a Data Color
Microflash colorimeter. An X-Ray diffractometer (XRD) is used to
determine valentinite. Higher valence antimony oxides are determined
by ethylene glycol digestion. Trace elements are determined by
inductively coupled argon plasma (ICP), hot graphite atmosphere
atomic adsorption (HGAA), or atomic absorbtion (flame AA).
DETERMINATION-POTASSIUM PERMANGANATE TITRATION
8 February 2010-USAC
Weigh 1.0 gram for mill tails, leach residue;
slag; 0.5 grams for wet or dry sodium antimonite, low grade ore;
0.2 grams for hand sort, metal, and mill concentrates.
Place in wide mouth 500 ml Erlenmeyer flask
with 25 mls of concentrated sulfuric acid.
Set the flask on a hot plate adjusted to
100-105 degrees centigrade and digest for at least 45 minutes
until the white fume reaches the top of flask.
Add 1 small spatula (approximately 200 mgs)
of hydrazine sulfate 3 times at least at 5 minute intervals.
The hydrazine sulfate reduces all the antimony to the plus three
valence. It is important to fume for at least 20 minutes after
the last addition of hydrazine sulfate to ensure that all the
hydrazine sulfate (a strong reducing agent) has been used up.
If this does not happen, you will be titrating the hydrazine
sulfate and you may not reach an end point. Do not evaporate
Remove when refluxing reaches top of flask.
(when white smoke reaches top of flask and small rivulets of
water run back down in flask).
Cool. Wash down sides of flask with 25 mls.
of water and 40 mls. of concentrated hydrochloric acid.
Boil 3 minutes. This volatilizes the
Cool and wash down sides of flask with water
diluting to 300 mls.
Filter heads and tails before titration.
Add 20 mls. of concentrated hydrochloric acid
in mls X
factor X 100 = % Sb
Sample wt in grms
in mls X
factor X 100 = % Sb
First all the antimony is reduced to the plus
3-valence state. On titration, it is oxidized to the plus
To prepare the titer add 2 grams of potassium
permanganate per liter of water.
(Approximately 0.004 grams of antimony/1 ml of titer)
To standardize titrate 0.25 grams of antimony metal 3 times to
determine the factor.
500 ml wide
mouth Erlenmeyer flasks.
accurate to 1 mg.
50 ml. buret.
with buret clamps.
funnel and paper.
mortar and pestle.
CP antimony metal.