Waste processing question

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martymcfly

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Jul 20, 2013
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I have a question to do with dealing with some waste i have left over, I hope someone would be good enough to answer for me.

My question is when dropping heavy metals from solution would it be acceptable to just raise the ph all the way up without the use of iron at around ph 2.5? Would this not force all metals out if im not looking to process them any further?

my thanks in advance.
 
My question is when dropping heavy metals from solution would it be acceptable to just raise the ph all the way up without the use of iron at around ph 2.5? Would this not force all metals out if I'm not looking to process them any further?

https://www.google.com/search?q=metal+hydroxide+solubility+vs+ph&tbm=isch&source=iu&ictx=1&fir=6VgjzWCnjA0nPM%253A%252CcmI4Cn4qeZ1M3M%252C_&usg=AI4_-kTJtZ1SFBQK-WyBHKyqXPPf15UGOg&sa=X&ved=2ahUKEwjA9vyU39fgAhWWvJ4KHW6PDVAQ9QEwBHoECAEQDA#imgrc=_


The chemistry does not work that way,

The problem is you cannot just raise the pH and precipitate all of the metals, the solubility of the metals vary from metal to metal and at what the pH value of that metal is at the time.

Using a metal like iron to displace metals from solution will remove metals from the solution which can even become more soluble as the solution becomes more basic.

Many metals are amphoteric they will precipitate with adding a base solution, but as you add more base solution the metal dissolves or becomes more soluble in solution...

Do some study in dealing with waste, the understanding of the principles will be many of the basic principles you will need to become successful at recovering and refining gold, and understanding much of the chemistry involved.
 
OK, so the simple answer is that you want to cement out onto Iron so that you end up with all the other metals as metals rather than salts. The you raise the pH to precipitate Iron Hydroxide, which is a reasonably safe, metal salt (It turns into rust)

If you directly precipitated all the metals as salts, you would still end up with some fairly unpleasant metal salts.
 
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