stock pot question

[Drowningbodacius]

Ok so I was reading in hoke that when you precipitate your stock pot with zinc you get a black powder. Now I cemented a stock pot of HCL/H2O2 with al and I got a reddish brown powder is this because I used al?

 

[nickvc]

It's better to use copper in your stock pot or iron, when using copper only the values cement out when using iron copper and anything less reactive and values cement out. By using aluminium you have cemented most metals out and if you had used zinc the same applies minus one or two elements. You now have to dissolve all those metals again to get to your values, a waste of acids and time.

 

[Drowningbodacius]

O ok. It was a small batch about 200ml that I had laying around and I just wanted to clean it of metals so I could safely dispose the liquids later. Thanks again for clearing that up for me