Silver Recovery Techniques: How to Extract Silver from Nitric Acid Solution

Silver is a valuable precious metal that is used in various industries. If you have silver that is dissolved in a nitric acid solution, you may be wondering how to recover it. Fortunately, there are several methods you can use to recover silver from the nitric acid solution.

The first step is to mix equal amounts of water and diluted nitric acid in a beaker or container. Before handling nitric acid, it is important to wear appropriate safety equipment, such as gloves and goggles, to protect yourself from its harmful effects. Carefully pour the diluted nitric acid onto a container holding electronic silver connectors or contacts, and wait for the reaction to start. After a few moments, the reaction will begin. Wait until all the base metal is dissolved, then filter the solution to remove any impurities.

Next, add a pinch of sea salt to the solution, stir with a rod, and wait for the silver chloride to settle at the bottom. Silver Ag can be recovered from nitric acid HNO3 as silver chloride AgCl, by using sodium chloride, NaCl (table salt), hydrochloric acid HCl, or other chlorides like potassium chloride.

AgNO3 + NaCl --> AgCl + NaNO3

AgNO3 + HCl --> AgCl + HNO3

AgNO3 + KCl --> AgCl + KNO3

Silver chloride is a white insoluble powder, and it is not advised to dry it as it can make the conversion to metal very difficult later. Normally, it should not be melted as silver chloride is volatile in high temperatures, and silver can go up in smoke. It can be converted to silver metal through various methods, such as with sodium hydroxide and glucose syrup, dilute sulfuric acid and iron metal, or dilute HCl and aluminum.

Another method to recover silver is through a displacement reaction using a metal higher in the reactivity series of metals like copper. This will give us a silver metal powder, and we call this process cementing silver from solution with copper.

2AgNO3 + Cu --> Cu(NO3)2 +2Ag (S)

This method is preferred as it results in metallic silver that can be easily melted after washing the contaminants. Note that copper will also cement palladium or platinum if it is involved in the silver nitrate, which can be recovered later in the silver purification process.

It is important to note that silver is not the only precious metal that can vapor off in a melt with chlorides; gold is also volatile and can go up in smoke in a melt with chloride salts. So, if you have to (or for some reason choose to) make silver chloride, it is best to keep it wet and convert it back to the silver metal before melting it.

In conclusion, there are various methods you can use to recover silver from the nitric acid solution, including using a displacement reaction with copper or converting it to silver chloride and then back to silver metal. Always use appropriate safety equipment and handle nitric acid with care.