Actually I have leached cons with the HCl/Cl method.
Smelting is used in mining, sometimes it's the only way to separate metals from others efficiently. For example, if there is not enough silver to dore it and run as a silver proposition, then the silver has to either be upgraded, or removed. So it's often smelted with another metal it has more affinity for and thus is separated from the other amalgam. Then the process is repeated to separate out the other metals.
Also, depending upon the type of ore you are dealing with, the cons may be incinerated or roasted to convert chlorides to their metallic form, or to drive off sulfides, etc.
Precious metals often times are not in their metallic form when mined. There are actually very few that exist naturally in their metallic form, most are in their mineral form and must be somehow converted into their metallic form.
All of the processes that I currently use to recover and refine PMs, with the exception of one, have been used 100s of years before electronics were ever dreamed of. Point in case is Aqua Regia, it was first discovered at used in AD 800 by the Persian Alchemist Geber. And smelting goes all the way back to the copper age, even before the bronze age. So Aqua Regia, chemical refining with acids, is about 1200+ years old, and smelting, which started during the copper age, goes back over 5000 years. And there were obviously no computers back then.
Scott
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