- Pour 10 ml of PCB etchant and 10 ml of distilled water in a glass cup.
- Add a piece of steel wool to the solution. Mix the liquid until you get a color change. The solution should become bright green (green is the FeCl2).
- Filter the liquid through filter paper or a coffee filter. Keep the liquid; discard the filter.
- Precipitate the magnetite out of the solution. Add 20 ml of PCB etchant (FeCl3) to the green solution (FeCl2). If you are using stock solutions of ferric and ferrous chloride, keep in mind FeCl3 and FeCl2 react in a 2:1 ratio.
- Stir in 150 ml of ammonia. The magnetite, Fe3O4, will fall out of solution. This is the product you want to collect.
The next step is to take the magnetite and suspend it in the carrier solution.
