operate the silver recovery unit with
(3) Drain the water supply system when the
the operating control set to LOW for
space heater is not in use.
This will coat the
(4) Store the chemicals in a warm place.
cathode with a hard, metallic silver
(5) Operate the immersion heater in the sink
and melt snow to provide water for the water tank if
g. Set the silver recovery unit control on HIGH and
operate the unit for the amount of time calculated in d
2-11. Silver Recovery Unit Operating Procedures
a. Place the silver recovery unit in a convenient
h. Disconnect the power cord; set the control to
place in the shelter.
OFF and remove the power head and check the fixer
b. Lift off the power head of the silver recovery
solution in the silver recovery unit tank to insure that the
unit (fig. 2-17) and fill the tank to approximately 1-inch
silver has been completely recovered. If silver remains
of the top with exhausted fixer solution.
in the fixer, recalculate the time required as described in
c. Test the exhausted fixer solution for silver
d above and repeat g above.
concentration with silver estimating papers.
d. Calculate the operating time required in
If a black deposit accumulates on the
accordance with the following example:
cathode it may indicate that the
exhausted fixer did not contain
The capacity of the silver recovery
Check the fixer solution
unit tank is 2 gallons.
carefully for silver content and if
none is indicated discard the fixer
solution. If silver is present, repeat d
above and set the silver recovery
1/2 troy, ounce/hour
0.64 troy ounces/per
unit control to LOW. Do not discard
= 2.5 hours
the soft, black deposit accumulated
on the cathode or that may have
e. Replace the power head.
fallen to the bottom of the tank.
f. Connect the power cord into a convenience
i. After the silver has been completely stripped
from the solution, disconnect the silver recovery unit
When the server recovery unit is first
from the power source, remove the power head and
placed into operation, or after the
empty the tank into a drain.
Figure 2-17. Silver recovery unit.
desilvered. To desilver the cathode, proceed as follows:
2-12. Removal of Silver and Sliver Recovery Unit
When the thickness of the cathode and silver plate is
a. Turn the unit off and disconnect it from the
between 3/8- and 1/2-inch thick the cathode should be
Change 6 2-22