Supplementary Treatment

There are only a few copper refineries to work up the entire tonnage of the metal produced in this country; the amount of precious metals found in the blister copper is considerable, and it therefore results that there is a good deal of material to be separated and provided for in a silver refinery.

The dore metal which is obtained from the preliminary fusions just mentioned is cast at those same, furnaces into anode shapes and electrolyzed in nitrate-acid solution to obtain a deposit of remarkably pure silver on the cathode. The silver thus obtained will be merely remelted in large crucibles and cast into bars for market. From the electrolysis of these anodes a residue results which contains all the gold, palladium, and platinum originally present in the copper ore. These metals will be assembled and separated by either wet or electrochemical means to be cast finally into bars of pure gold, palladium, and platinum.

Importance, The silver department of a copper refinery thus is quite extensive in its scope and really handles a surprising amount in money value. As several of our largest companies operate both lead and copper refineries, it is common to draw the dore metal from the different refineries together in this same department; thus the American Smelting & Refining Company at its plant at Maurer, New Jersey, gets the precious metals from various plants and operates the largest silver refinery in the world.