ammonia rinse treatment

[mls26cwru]

okay, I have been trying to find some info on treating ammonia rinses... I vaguely remember reading something about it, but cannot find it.... Does someone have the info or have a link to it?

Basically i was using ammonia to dissolve silver chloride from my precipitate... I know it shouldnt be added to my other waste and treadted seperatly, but i am coming up blank on how to treat it. Is it treated the same, just seperate of my other acid wastes?

Thanks for the help,
Mike

 

[METLMASHER]

treating ammonia rinses

I pasted this in the search bar above and got 10 pages of posts. Don't know if it helps, but there is info there.

 

[mls26cwru]

yeah, i have been combing through the posts, but i have seen a few posts by Steve and Lou and 4metal that you should keep them seperate because it can be problematic when it comes time to treat your waste.... so thats what im looking for, is if there is a way to treat ammonia waste as opposed to my other acid waste.

M

 

[FrugalRefiner]

Mike
For safety's sake, you want to reacidify the rinse solution promptly. If there was any silver chloride, it will go into solution with the ammonia. That can create explosive compounds. Add HCl to the ammonia rinses untill the pH becomes acidic again. Any silver will be precipitated again as relatively clean AgCl.

You should be able to find more complete information with METLMASHER's words.

Dave

 

[mls26cwru]

Mike
For safety's sake, you want to reacidify the rinse solution promptly. If there was any silver chloride, it will go into solution with the ammonia. That can create explosive compounds. Add HCl to the ammonia rinses untill the pH becomes acidic again. Any silver will be precipitated again as relatively clean AgCl.

You should be able to find more complete information with METLMASHER's words.

Dave

Thanks Frugal. I added enough HCl to turn the solution acidic...now what do i do with this solution is the question. Can I chemicly treat is as i do with my other acid wastes? or is there another process I should follow?

 

[MarcoP]

If any silver chloride formed, decant and wash. All I know is that now is safe for storage. The cool part is looking at the AgCl cloud forming for reach drop of hydrochloric acid used.

 

[butcher]

Lets assume we have copper and silver as an soluble alkaline amine solution,
Ag(NH₃)₂ + Cl- and Cu(NH₃)₄Cl₂

Adding HCl Acid we precipitate silver from the solution, as silver chloride AgCl solid powder, in an ammonium chloride solution.

Ag(NH₃)₂Cl^- + 2HCl --> AgCl(s) + 2NH₄Cl (aq)
This removes the silver compound that posed the solutions danger if concentrated with heat or dried...

Removing our silver chloride powder for processing later to make silver metal with other chemical reactions.

Copper amine in solution follows a similar reaction with the acid, but no precipitant occurs as both products are soluble copper chloride and ammonium chloride.

Cu(NH₃)₄Cl₂ + 4HCl --> CuCl₂(aq) + 2NH₄Cl(aq)

Just a little excess acid here wont hurt and can be benificial.

Now if we add iron metal ( to this acidic solution) we can cement or displace the copper from solution, removing copper from the solution leaving us with an iron chloride (mixed with our ammonium chloride),
CuCl₂(aq) + Fe(s) --> Cu(s) + FeCl₂(aq)

letting the copper settle and decanting the solution, leaving us with an iron chloride and ammonium chloride solution, adding sodium hydroxide we can now raise the pH (around pH9), and precipitate the iron (and most any other base metals the may have been involved) removing iron and base metals from solution as insoluble powder hydroxides, then after decanting the caustic solution from the powders, we can add enough acid to bring the pH to neutral (pH7) we are left with a neutral solution of sodium chloride and ammonium chloride salt water which can be evaporated safely or disposed of in a safe manner.

Basically after removing your silver you treat this waste like you would do your other waste.
just treat it separately from your other acidic waste solutions.

 

[mls26cwru]

Thank you Butcher! Your vast knowledge never ceases to amaze me

I read a number of places about the reacidifying and warnings about not adding it to other acidic wastes, but was unsure how to procede from there. I try to be absolutly certain before I do something in this hobby especially when it comes to waste treatment. The ammonium chloride was concerning me.

Thanks again!

M