It’s not really “professional” but you can look at the process, see the results and come to your own conclusion about it’s viability.
NurdRage made a video a few years back, comparing multiple methods (rust, wet chemical, and electrolytic) of preparing iron oxide, and the benefits and drawbacks of each.
This is a mixture of oxides, hydroxides, and nonoxidized iron chunks and who knows what else. Also probably some chlorine gas to breath in.
At temperatures where iron II oxide oxidizes to III state, any iron hydroxide would decompose. Any other impurities but carbon can be washed off.
About chlorine i couldn’t even smell any throughout the process.
Nonetheless it works great for thermite.
Just to be safe you might consider replasing chloride with sulfate.
Sure this is great way to make thermite or anything that does not exactly care about oxidation state, that part I can confirm.
Furthermore, you are close to iron(6) synthesis here using drain cleaner. Yield would be even lower, but fun is worth it. Be careful though, when literature states it blows up, they mean it.
