Answer to Question #56507 in Inorganic Chemistry for Dale

Question

I would like to salvage isotopic Cadmium from old tubes. The tube contain from 3 to 5 grams of Cd.

Generally, I dissolve out the Cadmium with acids, i.e. HCL, H2SO4 or HNO3. This leaves me with an acid Cadmium solution. There usually are not any percipatates, but I assume it produces Cadmuim Sulphide, Cadmium Oxide etc.

How can I complete the process to drop out the Cd in pure metal form.

Example,...Copper Sulphate mixed with Iron filings will drop out the pure Copper metal and form Iron Sulphate.

Answer 1

1. When you dissolve Cd in acids, it is transformed into Cadmium cation.
2. Cd metal can be precipitated by single exchange reaction with more reactive metal like Fe, Zn or Mg.
Fe + CdSO4 = FeSO4 + Cd.
Or I would recommend you to use electrolysis. It's much more effective in metals purification.