Error creating thumbnail: Unable to save thumbnail to destination
|This article is a stub. You can improve Gold Refining Wiki by expanding it.|
Silver nitrate dissolved in water and with some nitric acid is the base of the electrolyte in silver cells.
Silver nitrate reacts with skin and nails and forms black spots that takes a long time to disappear. Longer contacts can be corrosive and cause blistering. Can cause blindness if splashed in the eye.
Dry silver nitrate reacts violently with magnesium and can be ignited by humidity.
Mixing silver nitrate with alcohol creates silver fulminate that is violently explosive when it dries.
Silver nitrate can be reduced by heating, the breakdown is governed by the following equations:
2 AgNO3 = Ag2O + 2 NO2 + 1/2 O2 (1) 2 NO2 = 2 NO +O2 (2) 2 AgNO3 = 2 Ag + 2 NO2 + O2 (3) Ag2O = 2 Ag + 1/2 O2 (4)
Ag2O is quite unstable above 130° C so equation (1) and (4) will never reach equilibrium under normal atmospheric pressure. Qualitatively, decomposition is negligible in the solid state, but becomes appreciable 30-40° C above the melting point. Silver nitrate melts at 209.7 °C (409.5 °F; 482.8 K) so it starts to decompose around 250° C and totally decompose at 440° C.
Reduction back to silver
There are many methods to take silver nitrate back into silver, either directly or via an intermediate silver compound.
- Reduction by formaldehyde or a number of ...
- Reduction by sodium formate
- Cementing with copper or other metal
- Adding chloride ions to precitate silver chloride
- Heating until decomposition
- GRF : 4metals recipe on sodium formate reduction to fine silver
- GRF : Pictures of silver nitrate crystals
- NIST : J. Phys. Chem. Ref. Data, vol 1, no 3, 1972 (Decomposition of Nitrates and Nitrides) page 766-767
- Salt Lake Metals : Silver facts
- Crystal growing : Silver nitrate facts
- Sciencelab : MSDS for silver nitrate (pdf)