Disposal of waste after recovery of silver

[chandler_P]

Hi guys!

This site is very informative specially in recovery and/or refining of precious metals. But i guess it is also important to discuss about the disposal of waste after recovering of metals such as silver or gold.

Could we just throw the waste solution into sink or sewer like after recovering of silver from films or fixers? In my case, caustic soda and xray film after the silver has been recovered
(btw, many thanks to Manuel and Lou for helping a newbie like me in silver recovery). I think this is a good discussion as everyone is trying to care for environment which is why we recycle or recover these metals.

P

 

[nickvc]

There are many posts and threads on the forum concerning the safe disposal of waste, use the search function top right of your screen and I'm sure you will find advice on the proper way to dispose of any chemicals we use.

 

[chandler_P]

Hi nick

Yes, you are right! there are different techniques of disposal of waste in this forum. Still i feel it would be better for people searching on the proper disposal of waste if we could arrange them so that it could be easily seen.
(i.e. For gold: using aqua regia - disposal; proper disposal of fixer after recovery using this x method)

Cheers!

 

[nickvc]

Acids are fairly easy to treat following cementation techniques, your tested solutions can be stripped of copper by putting steel into the solution, after that drop the ph to neutral with lye and all other metals will drop as fairly harmless powders which can be filtered and dried and put in the bin and when the solution is neutralised it's safe to pour into the drainage system. The big worries with nitric or AR solutions is either silver or copper getting into water courses as they both very effectively destroy bacteria, good and bad. I'm not to sure on the disposal of fixer but I'm sure GSP or Manuel will know what to do to make it safe.

 

[NoIdea]

Afternoon All – I have mentioned it once in another thread but had no pictures, so I will try it again with pictures.

The filter I used is a empty mentholated spirits bottle with it’s bottom chopped off, an 8mm to 10mm hole in the lid, a cotton face cleaning pad (balls should be ok) jammed into the inside up against the hole, wet it and push it in some more, pour about an inch of clean sand on top of the cotton, and then jam a nylon stocking in on top of the sand, rinse through with a little water, and bingo your ready to filter mud. Note: Don’t leave out the stocking, other wise it will take way longer to filter.



The pictures here are the bottle after 6 filtrations. The one showing the inside view is how far I can go before hitting stocking, which is left as-is for the next lot. I pour at night and it is ready for scooping in the morning.

The last picture is the precipitate after it has air dried, using an old microwave oven tray set outside in the sun.



The alkali I use is hot wash wood ash from a friend’s fire place (ours no go anymore). This can be prepared similar to the filter method above except you leave out the stocking and sand. I premix the ash in a steel container using hot water (1:2 ash/boiling water), scoop out the floating charcoal (which I save and use in my incinerator), and then pour the entire contents into the filter, with filtration lasting about 10min. The filtrate has a high pH, pour into your spent liquid waste and watch the mud develop.

You can also check the filtrate after mud filtration by adding a little bit more of the alkali solution, checking for any further precipitation.

 

[chandler_P]

No Idea,

Nice photos.
is this for the fixer disposal?

Nick,

Thanks for the very info on acid disposal.

For recap:

After silver is recovered, disposal of waste:

Using caustic soda - if the ph is at level 5-7, we could pour into drain

Using clorox

Using nitric - follow nick's acid disposal

oxalic treatment -

Have nice day guys!

 

[Juan Manuel Arcos Frank]

Chandler_p:

NaOH process attacks gelatine in the emulsion,so you will have NaOH as waste that you have to neutralize with some acid to 5-7 pH level.

Chlorox process releases chlorine and you have to neutralize to 5-7 pH level.

Nitric acid process releases NOx fumes and you have to neutralize to 5-7 pH level.

Oxalic acid could be used for 3 times,at least,so pH level is closer to 5-7 pH level and acid wastes are reduced

Iron chloride process is the best,because the waste(iron chloride) is used as flocculant in waste water treatment plants so you can pour it off to the drainage with no problem.

I hope it helps.

Kindest regards.

Manuel

 

[chandler_P]

Hi Manuel,

Very well explained and you help us a lot with this information.

More power to you!