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Refining Process
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Refining is a chemical process that purifies a particular metal. Mankind learned long ago how to separate silver and gold into nearly pure metals. They did so without the use of electricity or a scholarly understanding of metallurgy.

Today we use mild acid or alkaline baths and a specific current density. The power source must be high-quality because a dirty current will screw it up. It's not unusual to spend a few thousand dollars on a device that weighs more than the average person but only delivers as much current as a battery charger. A good one will also be capable of electroplating, electrostripping, and more.

In one method the silver dore bar is suspended in the acid bath with an electrical lead attached to it. Also in the same bath is the electrode that will accumulate the pure silver. With the correct current, pure silver atoms deposit on the cathode. After cleaning and testing they are ready to be melted.

 
While the intention is wholly good the end result is far from desirable, consistent, or precise.
 
Most of the contaminants dissolve into solution; the others will precipitate and fall to the bottom. The pure silver will flake off the good electrode so it is important to keep the good stuff separate from the bad stuff. For that reason one or more filters are strategically placed to block and contain.

After a while, the solution becomes saturated with impurities. In simple terms, it will no longer work. The rogue elements will begin to deposit on the electrode and ruin the batch. Copper is the usual suspect as it is the most common alloying agent but there will probably be nickel, zinc, and some unfriendly metals.

For those buying supposed sterling silver scrap and melting it for re-use, there are several problems. Not only is the purity and metal composition unknown beforehand - and it likely will never assay to .925 regardless - but things change after melting. There could be toxic substances lurking about, too. Certain countries have laws dictating which metals are not allowed in jewelry and those happen to be the same ones removed by refining. While the intention is wholly good the end result is far from desirable, consistent, or precise.

In the USA, the law is quite specific on the purities that must be guaranteed. It is illegal to falsely mark, stamp, imply, or otherwise indicate something is sterling silver or any marked standard when it isn't. Rest assured that people will try to be alchemists albeit with a stamp and hammer instead of a bevy of flasks and test tubes like their forefathers.


Posted by M: May 2, 2018


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