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Date: | Fri, 15 Sep 95 09:56 EST |
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Text item: Text_1
An additional comment to John Monaghan's excellent reply to Paul
Walker.
Routine maintenance of the anode baskets definitely improves plating
consistency. It avoids changes in the copper surface area distribution
as the older (smaller) nuggets settle to the bottom of the basket. It
also keeps sludge choked bags from being a problem.
We made a sieve by drilling holes in a polypropylene plate that fit
half way down into a large bucket. This allowed us to dump the basket
out, rinse off the sludge and sort out the too small anode fragments.
Nuggets large enough to not pass through the sieve were reused. Never
reuse old anode bags, and leach out the new ones before putting them
on the basket.
We found that when we used enough baskets to get good current
distribution in our tanks the copper concentration would rise because
of all the surface area. Our trick was to place a length of small
plastic pipe in the baskets before filling them with copper. This
reduced the available volume in the baskets uniformly top to bottom
while providing the same effective current distribution.
A length of larger diam. plastic pipe is useful to slide copper
nuggets into the top of the baskets on-line without much chance of
them ending up in the bottom of the tank. It's also handy for knocking
the copper down into a tightly consolidated mass in the basket.
Andy Magee - Applications Engineer
Rogers - Circuit Materials Unit
Tel: (602) 917-5237
Fax: (602) 917-5256
E-Mail: [log in to unmask]
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