# How To Dispose Of Used Acids



## Gold-Digger (Apr 22, 2007)

How is everyone disposing of their used acids. I do this at home so need something that will allow me to flush down the drain without the sewage people giving me a nasty call. Eco-Friendly??

I have two techniques at my disposal which work to normalize the Ph.

1. Baking Sode
2. Lye

Is there anything else I need to do other than normalize the Ph then flush? Of course, all of the materials have been filtered, etc.

Or what would you suggest?


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## Noxx (Apr 22, 2007)

If you have base metals in solution like copper, lead, etc, you should precipitate them all with Aluminium before disposal.


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## Gold-Digger (Apr 22, 2007)

What is your recommended form of aluminum?

1. powder form
2. shavings of aluminum 
3. bar of aluminum

Thanks for the help!!!!!!!!!


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## Noxx (Apr 22, 2007)

The form doesn't change anything exept the reation speed.
Aluminium powder will react mostly instantly. 
It's better to use aluminium bars or parts from computers since they are free. I habitually use heat sink.


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## Noxx (Apr 22, 2007)

And if you're dealing with a lost of scrap, you'll be able to drop a lot of copper wich could be sold to scrap yard. But it must be melt before and it takes a lot of energy.


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## Gold-Digger (Apr 22, 2007)

Are there any recommendations or suggestions to drop Platinum or other expensive metals before adding aluminum powder?

As an example, you would normalize the Ph after getting the gold. Then put in additive #1 to drop other expensive metals. Then add aluminum to get the junk out so you can flush down the drain.

thanks again!!!


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## Noxx (Apr 22, 2007)

Well, I don't really know. Maybe Harold or Steve would have a clue ?
But as far as I know, you can't do this... You would need to reprocess everything than add a precipitant. But you could just test your solution to see if there is any precious metals left.


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## lazersteve (Apr 22, 2007)

Ammonium Chloride will drop Pt as an orange powder.

Ammonium Chloride followed by Sodium Chlorate will drop Pd as a red powder.

Steve


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## Gold-Digger (Apr 22, 2007)

So these two percipitants (ammonium chloride and sodium chlorate) be used at Ph 7 or when in an acidic solution, i.e. Ph 2.

Thanks!!


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## lazersteve (Apr 22, 2007)

Acidic.


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## Gold-Digger (Apr 22, 2007)

When adding Aluminum powder to drop out the Copper does this also need to be acidic or neutralized or does it matter?

Thanks again!


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## goldsilverpro (Apr 22, 2007)

I wish Harold would get involved in this discussion. He has some excellent posts on this subject but, I can't seem to find them. The forum has grown so fast that everything is scattered. Harold has lots of good experience cleaning up solutions with aluminum and iron.


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## lazersteve (Apr 22, 2007)

<=ph 7


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## Harold_V (Apr 23, 2007)

lazersteve said:


> Ammonium Chloride will drop Pt as an orange powder.
> 
> Ammonium Chloride followed by Sodium Chlorate will drop Pd as a red powder.
> 
> Steve



Please pay attention to this:

The platinum group rarely precipitates from dilute solutions by that procedure, and won't always precipitate completely from a concentrated one. You can recover those trace values by following instructions, below. 


Steve. I know you bought a copy of Hoke's book. In it, she talks about a stock pot. It's nothing more than a container in which you dump solutions that contain traces of values. To keep expenses down, you can use scrap steel (angle iron, etc.). It precipitates everything, but it's the easiest way to recover these values. Just keep adding solutions to the pot, decanting the solution after everything has precipitated. You'll know by the absence of color in the solution. Decant it and allow it to settle a second time, saving anything that settles out. You can expect the values to look similar to that which comes from your stripping cell---black, and eager to rust when it dries. When you have enough of the crud to filter, do so, then dry it and store it, filter paper and all. You'll incinerate the entire lot before attempting recovery at some time in the future. You can do that chemically, or by furnace reduction. The whole idea here is to concentrate the traces until you have enough to recover successfully. I've done it countless times in my years. 

Steel in your stock pot is consumed slowly, so you must add occasionally. You can also use scrap aluminum, but it reacts quite rapidly and can be the source of considerable gas and heated solutions. Steel was always my choice. Don't throw away anything that comes out of the stock pot, regardless of how useless it may appear. If it isn't consumed by the chemicals, it should be incinerated along with the values you've saved. You'll notice that they stick to everything, which is the reason to recycle what ever comes out of the pot. 

If, by chance, your solution is extremely high in copper and you prefer to not precipitate it with the values, you can recover them by using copper instead of steel or aluminum. Again, you'll be looking for a black precipitate, but it will be sparse, as you might imagine. 

Harold


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## lazersteve (Apr 23, 2007)

Harold,

The information I posted came right out of the pages of Hoke's book.

Steve


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## Gold-Digger (Apr 23, 2007)

By chance I had some aluminum shavings from my metal cutting band saw. 

I put these into this solution that was green in color that I had normalized with baking soda so close to Ph7.

I go out this morning and there's a bunch of green at the bottom and all the water is nice and clear.. Looks like it worked!!!!!!!!!!!!!!! Wha hoo!!

I'm assuming with this green sludge left overs I need to collect in a separate container and take them to solid waste when after I've collected 20 or 30 pounds?

Thanks!


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