There are two methods: working with saltwater and working with acid. Both work equally as well, but for a variety of reasons, including safety, cost, and the kind of material that you are refining, you may choose to use one method over the other.
There are two methods: Chemical and Electrolytic processes. If you’re refining purely chemically, you will have to use dilute nitric acid. Sorry, no way around that. However, if you choose to refine using the electrolytic way, then the nitric acid will be diluted, resulting in relatively few fumes.
The process for the Simplicity method is simple: Hang your metal on a wire that is connected to a car battery charger and then immerse the metal in saltwater in the Simplicity (or similar) unit. Turn on your battery charger. An electric current will run through the metal causing it to dissolve at a rate of about 1 ounce per hour. Once all of the metal is dissolved, add a selective precipitant, such as Quadratic, to the solution. Only pure gold will turn back into solid metal. For all of the other metals, the impurities will remain dissolved. The resulting gold is at least 99.95% pure gold.
The platinum group metals (or PGMs) include platinum, palladium, rhodium, iridium, osmium, and ruthenium. Platinum, palladium, and rhodium are commonly used in industry and jewelry.
By simply recovering the precipitated metal between each precipitation, you can achieve a purity of at least 99.95+ purity for each platinum group metal.