Applications of electrolysis

I'll have to admit that I keep neglecting all of the applied stuff when I study chemistry. Now it's time for me to partially make up for that with this little post on the applications of electrolysis.

No diagrams yet, sorry. If you don't know what an electrolytic cell looks like, check out my post on electrolysis.

All right. Let's get down to business.

Electrorefining, also known as electrolytic refining, is the refining of an impure substance using electrolysis (as can probably be inferred by the name). At the anode, you have the metal to be refined, while at the cathode you have a small piece of very pure metal.

The way that electrorefining works is that, at the anode, electrons are removed so that the metal and its impurities become metal ions and dissolve into the electrolyte. At the cathode, only the ions of the metal that you want refined become metal again. All other ions remain in the electrolyte solution, though I think some might come out of solution and form a sort of "anode mud" at the bottom- possibly less reactive substances like gold, silver and platinum. Could someone please clear this up for me?

Electrowinning, or electroextraction, is the process of extracting metal from an electrolyte solution. (Sometimes this is done after electrorefining, to get all of the impurities dissolved in the electrolyte solution which could consist of metals such as zinc and nickel.) The metal ions are reduced at the cathode to become metals again.

Anodisation is a way of coating a substance such as aluminium with an oxide coating in order to protect it. In anodisation, the metal to be anodised is the anode (hence "anodisation"). The electrolyte is a solution such that water is the substance being oxidised at the anode to produce oxygen.

That's it from me... for now. Maybe I should study Spec later... stuff that, I'll let myself relax first.