To separate silver from a mixture with aluminum, one effective method is to selectively dissolve the aluminum using hot aqueous 10% sodium hydroxide (NaOH), which leaves the silver intact. This process is similar to creating Raney nickel from an aluminum-nickel alloy, where the aluminum is dissolved, resulting in a porous nickel sponge. After the aluminum is removed, a final treatment with weak nitric acid (HNO3) can help eliminate further impurities, followed by melting the remaining material with a flux to yield purified silver beads.For converting silver metal to silver nitrate, a stock solution of 68% HNO3 is recommended, although the exact molarity may vary depending on the scale of the operation (small or industrial) and the form of silver (alloy or shavings). The discussion emphasizes the importance of controlling the dissolution process to achieve the desired purity of silver while managing the byproducts effectively.
