Question

How is Silver extracted?

Answer 1

Steps involved in the extraction of Silver:

By Mac Arthur and Forrest's Cyanide process, Silver can be extracted from their ore. This can also be done by leaching and smelting.

Step1: For the extraction, ore $\mathrm{A}{\mathrm{g}}_2\mathrm{S}$ is crushed into fine particles.

Step2: By the Froth Floatation, the concentration of ore is done.

Step3: The concentrated ore is then treated with $\mathrm{NaCN}$. The mixture is continuously stirred by air current. This leads the Silver ore to form a soluble complex. $$\begin{gathered} \mathrm{A}{\mathrm{g}}_2\mathrm{S}+4\mathrm{NaCN}\to 2\mathrm{Na}\left[\mathrm{Ag}{\left[\mathrm{CN}\right]}_2\right]+{\mathrm{Na}}_2\mathrm{S} \\ \mathrm{Silver}\mathrm{sulphide}\mathrm{Sodium}\mathrm{cyanide}\mathrm{Sodium}\mathrm{argentocyanide}\mathrm{Sodium}\mathrm{cyanide} \end{gathered}$$
Step4: The solution obtained gets precipitated and by filtration insoluble impurities are removed. The addition of Zinc dust leads the Silver precipitate out.
$$\begin{gathered} 2\mathrm{Na}\left[\mathrm{AgCN}\right]+\mathrm{Zn}\to \mathrm{Na}2\left[\mathrm{ZnCN}4\right]+\mathrm{Na}2\mathrm{S} \\ \mathrm{Sodium}\mathrm{argentocyanide}\mathrm{Zinc}\mathrm{Sodiumtetracyanozincate}\mathrm{Sodium}\mathrm{sulfide} \end{gathered}$$
Step5: In electrolytic refining, the impure Silver is made as an anode and a thin pure sheet of Silver will act as a cathode. The impure silver settles down as anode and pure silver gets deposited at the cathode when electricity is passed.
Thus, Silver can be extracted.