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| Dental laboratory scraps
are unloaded into top 10-mesh screen of 24-in (610 mm) diameter
Kason Vibroscreen® circular vibratory separator. |
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| Circular screener separates
scraps and sweepings for smelting. Top 10-mesh screen separates
large, unusable pieces. Middle frame port (right) discharges
below-10 mesh to 40- mesh precious metal particles. Bottom frame
port (rear of unit) discharges below-40-mesh precious metal
dust. |
Sifting precious metals from dental lab scraps
90% faster
AMBRIDGE, PA — Atlantic Precious Metal Resources
reduced sifting time by 90 when it went from hand sifting of scrap
and sweepings from dental laboratories to screening with a 24-in
(610 mm diameter circular vibratory separator.
The timesavings helped the foundry accommodate a recent doubling
of business. The Vibroscreen® separator from Kason Corporation paid
for itself in less than nine months out of labor savings.
APM recovers and refines particles o silver, gold, platinum and palladium
fro scraps and sweepings purchased fro dental laboratories and offices.
The scraps come from workbenches, suction unit filters, floor sweepings and
vacuum cleaner bags. After screening, the particle are smelted in
APM's four furnaces and sold as bars or ingots to precious metal
processors.
Sifting dental laboratory scrap
About 20% of incoming batches must be sifted since they arrive mixed
wit large pieces of paper towel shreds, straw from brooms, paper
clips, plaster pieces and plastics from impression trays. Batches
containing fewer foreign piece are not sifted prior to smelting.
Previously, APM operators took three hours to sift a typical 50
to 100-lb (22.7 45.4 kg) batch manually using kitchen type strainers.
Now, one operator, in 3 minutes, separates equivalent batch size
by emptying the contents of 5-ga (18.9 l) buckets onto the top screen
deck of the Vibroscreen® circular screener. The unit is positioned
adjacent to dust collector, which evacuates dust during operation.
"We leapfrogged fro Gold Rush days into the 21st Century with the
new equipment," owner Don Mappin, Jr. jokes.
The circular vibratory screener i equipped with an imbalanced-weigh
gyratory motor positioned beneath the screening chamber. The motor
impart multi-plane inertial vibration to the two spring-mounted
screening decks, causing oversize particles to vibrate across the
screen surface in controlled pathway to the screen periphery where
the are discharged. Screening efficiency improves by forcing material
to pas over a maximum amount of screen surface. Undersized particles
pass rapidly through the screen to a feed tray that directs them
to the screen beneath.
The top 10-mesh screen separate the large pieces, which exit the
to frame discharge, and are sent out for incineration.
From screener to smelter
The material falling through the 10-mes upper screen and retained
by the 40 mesh lower screen exits through the middle frame discharge
port into 5-gal (18.9 l containers for smelting.The below-40 mesh
precious metal dust exits the bottom frame discharge port in similar
fashion.
Batches of the 10-to-40-mesh particles which are sometimes combined
with the below-40-mesh dust, are then blended with flux and smelted
in one of four 18-in (457 mm) diameter gas-fired furnaces. The melt
is poured from the crucible into a cone mold. After cooling, the
metal (mostly gold and palladium) is capped off, assayed and sold
as bars or ingots.
Kason's representative Solid Solutions, Inc., McMurray, PA, specified
and installed the separator and dust collector.
As APM's business grows, its next goal will be to add furnaces.
"We could quadruple in volume before having to add another circular
vibratory screener," Mappin says. |
