P.O. Box 643
47 Cox Gulch Road
Thompson Falls, MT 59873

OTCB: uamy.ob

Phone: 406-827-3523
Fax: 406-827-3543
Email: tfl3543@blackfoot.net

QUALITY CONTROL

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 2 years.

WET ANTIMONY DETERMINATION-POTASSIUM PERMANGANATE TITRATION
8 February 2010-USAC METHOD

1. 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.

2. Place in wide mouth 500 ml Erlenmeyer flask with 25 mls of concentrated sulfuric acid.

3. 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.

4. 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 to dryness.

5. Remove when refluxing reaches top of flask.  (when white smoke reaches top of flask and small rivulets of water run back down in flask).

6. Cool.  Wash down sides of flask with 25 mls. of  water and 40 mls. of concentrated hydrochloric acid.

7. Boil 3 minutes.  This volatilizes the arsenic.

8. Cool and wash down sides of flask with water diluting to 300 mls.

9. Filter heads and tails before titration.

10. Add 20 mls. of concentrated hydrochloric acid and titrate.

Calculations:

Titer in mls X factor       X    100 = % Sb
 Sample wt in grms

Titer in mls X factor       X    100 = % Sb
   mls of aliquot

NOTES:

1. First all the antimony is reduced to the plus 3-valence state.  On titration, it is oxidized to the plus 5-valence state.

2. To prepare the titer add 2 grams of potassium permanganate per liter of water.
   (Approximately 0.004 grams of antimony/1 ml of titer)

3. To standardize titrate 0.25 grams of antimony metal 3 times to determine the factor.