Dealing with Waste

[Martijn]

Here is a pic of the dried crystals. 50gram. its from the boiled down and filtered liquid shown in the glass tray and the crystals precipitated in the flask a couple posts above.
The ferrous chloride is still in solution.

And I made some lead chloride to cool overnight to compare.
Will post those results when crystals have formed.

 

[g_axelsson]

50 grams of crystals seems a bit much, lead chloride isn't that soluble after all. Old solder was 60/40 tin / lead so it would mean you dissolved 100 grams of solder.

The density should be quite telling, 5.85 g/cm³ means 50g would only take up 10 ml of volume. Another check, solubility, 10 g/liter at 20 C so a gram should be hard to dissolve in a dl. Then if you add some sulfuric acid it would turn white immediately by the lead sulfate precipitating, just as silver nitrate reacts on chloride.

To me it looks like something else, the picture on wikipedia is quite good. It's crystals in a test tube.
https://en.wikipedia.org/wiki/Lead(II)_chloride

Göran

 

[butcher]

Soda ash (sodium carbonate) Na2CO3 and sulfuric acid produce a salt of sodium sulfate Na2SO4
Na2CO3 + H2SO4 --> Na2SO4 + CO2 + H2O

 

[NobleMetalsRecovery]

I just now read, "Waste treatment for the small refiner" posted by 4metals.

At the end you end up with clear water. What about the solids that remain? I figure there must be some lead compounds? How is this left over material properly disposed of?

 

[DylanDownright84]

I've been evaporating the waste solution from my silver cement bucket and have started seeing some things I have not seen before. The starting materials being silver nitrate solutions from batches of gold filled and inquartation processes. It's just a 5 gallon bucket loaded with copper and an aquarium bubbler to keep things flowing. Yesterday was the 5th day evaporating being down to the last four liters of solution left. I have about 2.5 liters left now and have been testing the solution periodically with stannous which will give a false positive of agcl I believe because when I add HCL to a small amount of the solution no white cloud of agcl can be seen. Just an emerald green with a dark spot on the bottom of my plastic testing spoon. And when I add a drop of stannous to the spoon I added HCL to I get a dark purple cloud looking like a concentrated positive for gold. The inside of the beaker has started to get a tan brown deposit on it and I've also had to add sulfamic crystals to it a few times to kill the live nitric that's been concentrated from the prolonged evaporation. I can feel something that's been pushed out of solution on the bottom of the beaker with my glass stir stick. I am currently awaiting an order of dimethylglyoxime to further test for Pd and it should arrive in the next couple of days. The stannous has shown positives for both gold and Pd and the solution has a ph of around 12. If I continue to evaporate I expect some metals will drop out, but with the solution being so concentrated now would I be better served to just dilute it with distilled water, let it settle, and see what I'm left with? I know the copper will have to go somewhere. Also, the solution immediately starts to crystallize upon reducing heat, the copper it appears to be, will verify tomorrow, and I'll be doing a few more tests tomorrow to try to further identify what all is in my waste solution. I'm partial to the copper cementation method as it conserves what little space I have. If its possible I'd like to separate the PMs from the waste concentrate. Before starting the evaporation the waste solution tested negative for agcl with HCL, but with stannous there would be a slight white crystal formation.

 

[DylanDownright84]

Here are some more pics of the stannous tests I've been seeing. Hope everyone is doing well and staying healthy! Thanks for looking.
Edit: HCL cleans up my small test batches and have been toying with the idea of just using HCL to clear up the copper in my solution then trying to separate the PMs.

 

[DylanDownright84]

Upon further testing the vitamin C had no effect on the small test solution. Before going to bed last night I pulled another small test batch and added HCL in equal parts and woke up to see that pink precipitate at the bottom when I just checked a little bit ago. I will most likely pull a larger test batch, add enough HCL to deal with the copper in solution and let it settle again. My solution isnt acidic anymore, maybe my test paper are just crap, but I'll get it back to acidic and that seems to drop the pink precipitate from solution which is testing positive for gold. Gonna spend another day researching.

 

[butcher]

I am having trouble trying to figure out what it is your doing so it is hard to comment.
I think I will just wait and see if I can figure out what is going on after you continue on with this.

So you evaporate the nitrates such as copper nitrate and the other nitrates to basic salts of the metals.
I do not understand the evaporation at this stage before you removal of the bulk of the metals from the solution...

and then form a highly alkaline or caustic solution, and test with an acidic tin solution or HCl...
I do not understand what is going on?

Then adding a slightly acidic solution in a test to these basic or neutral metal salts you would expect the oxidation state of some of the metal salts to change states and thus change colors in general.

Adding any acid or substance to change the pH may also produce a color change as base metals are oxidized, an acid such as HCl will also oxidize some of the base metals like copper and any other metal.

You may just be seeing copper or some other base metals changing states in your test.

Your stannous testing for gold should be done from an acidic solution, not a neutral pot of base metal salts...


The stannous testing for silver from your solution would be more indicative of the metal, but any chloride or even HCl would produce a similar milky precipitate.

I am lost for now, at least until I read more or can understand what it is I am reading.

 

[DylanDownright84]

I am having trouble trying to figure out what it is your doing so it is hard to comment.
I think I will just wait and see if I can figure out what is going on after you continue on with this.

So you evaporate the nitrates such as copper nitrate and the other nitrates to basic salts of the metals.
I do not understand the evaporation at this stage before you removal of the bulk of the metals from the solution...

and then form a highly alkaline or caustic solution, and test with an acidic tin solution or HCl...
I do not understand what is going on?

Then adding a slightly acidic solution in a test to these basic or neutral metal salts you would expect the oxidation state of some of the metal salts to change states and thus change colors in general.

Adding any acid or substance to change the pH may also produce a color change as base metals are oxidized, an acid such as HCl will also oxidize some of the base metals like copper and any other metal.

You may just be seeing copper or some other base metals changing states in your test.

Your stannous testing for gold should be done from an acidic solution, not a neutral pot of base metal salts...


The stannous testing for silver from your solution would be more indicative of the metal, but any chloride or even HCl would produce a similar milky precipitate.

I am lost for now, at least until I read more or can understand what it is I am reading.

Hey Butcher, and thanks for replying. The evaporating solution is the waste solution from my silver cement bucket after cementing out of all the silver using copper. Sorry for the long, mixed up post last night, my fault on that. Was trying to give as much detail as possible before going to bed. From what I've seen this far is that just adding HCL will drop a pink precipitate that tests positive for gold in AR. The resulting emerald green solution after HCL is added tests positive for Pt and Pd using stannous. I have DMG being delivered today, looking forward to that! I have no experience with PGMs, and have been scouring Hoke's book and the GRF on how to best, and simply deal with such. Unfortunately I have VA appointments today and all the rest of this week so I'll be intermittent on what all I can do till the evenings or this weekend.
Edit: so far I've identified gold, Pt, Pd, and Cu in what's left of my evaporated waste concentrate.
Edit again: I'm more or less trying to figure if I should attempt separating all the PMs or if I should just add the concentrate back to my silver cement bucket. This is new territory for me and so far I've avoided PGMs like the plague.

 

[FrugalRefiner]

Dylan, I'm as confused as Butcher was, and I'm still confused. This solution comes from your "silver cement bucket after cementing out of all the silver using copper".

First, I don't understand how you would have gold in your nitric acid solutions.

Second, you cemented the silver out of solution with copper. This should have also cemented out any gold, platinum, and palladium. These metals should have been completely cemented assuming there was sufficient copper and sufficient agitation in your solution, and there was still a bit of free nitric in the solution.

If I had your solution, I would decant all the solution off of any precipitates, add a tiny bit of nitric, and put some more copper into the solution. If there is any gold, platinum, and/or palladium in the solution, it will cement out. Then you can deal with the cement without any of the additional metals that may be causing your problems.

Best of luck with your VA appointments.

Dave

 

[DylanDownright84]

Thank you, Dave. Just got home a bit ago and left the heat off while I was gone. My solution hadn't completely solidified just yet. I believe I'm over complicating an otherwise simple process. I'm stuck between wanting to evaporate it all down to a crust then acidifying with HCL and moving from there. Theres no silver left in this solution and the copper bar I left in it has not been touched. I've been a bit confused myself because I use a pretty generous amount of copper in my cement bucket with prolonged agitation so I'm not sure why I'm getting the positive stannous tests I have been getting. Still reading up on the use of DMG. thanks again! And may the gold be with you.

 

[butcher]

Dave,
can I ask you to spend your valuable time and try and clear up this thread, possibly moving all of the later posts and irrelevance to the debate section, where it does not muddy up the thread of Dealing with waste ...

I have not learned how to move or separate the threads and if I tried no telling what mess I could make of it.
Remember when I tried something and next thing I knew I ended up banning every single member on the whole forum on accident and shut the forum down? I wouldnt want to do that again.

 

[FrugalRefiner]

Happy to help Butcher.

For readers who have been following the "debate" initiated by Jmk88, those posts have been moved to Dealing with Waste in the Debates and Discussions section of the forum.

Dave

 

[galenrog]

Thank you, Dave. The playground tantrums were a distraction, and added nothing to the conversation.

Time for more coffee.

 

[FrugalRefiner]

It was done at Butcher's request. I am but the blunt tool.

Dave

 

[galenrog]

I know that. I’ve also heard that Butcher can screw up moving things from one file to another almost as badly as I can, so I am glad you did it.

Note to Dylan. Perhaps it is the stroke talking, but I can not follow what you were doing. I do have a suggestion that works for me, however. Before beginning any procedure, list every step. Do not attempt to remember. I make flow charts for everything. I also label everything. I may forget what I did, but proper labeling, and notations in my flow chart helps me avoid problems.

I do the same thing with bread. The better my procedure is written, the better the bread.

It helps me recover from mistakes easier, too.

Time for more coffee.

 

[Yggdrasil]

I'm have a been growing a suspicion for some time here!
I do suspect you like your coffee
Have you hidden some golden grains in there :mrgreen:

Sorry, could not help myself

 

[galenrog]

I picked up the phrase “Time for more coffee” decades ago. An acquaintance of mine, retired a few times over when I knew him in the early ‘80s, used the phrase when he was tired of talking, or listening, or anything else. Usually he would say “Time for more coffee” and simply get up and walk out. He is long gone now, having been in his eighties when I was in my twenties. I began using the phrase on blogs and such to indicate that my comment at that moment was done. It has little to do with coffee, unless I actually want some right then.

In other words, just another tag line.

Time for more coffee.

 

[Yggdrasil]

Excellent, keep on

 

[g_axelsson]

I've been evaporating the waste solution from my silver cement bucket and have started seeing some things I have not seen before. The starting materials being silver nitrate solutions from batches of gold filled and inquartation processes. It's just a 5 gallon bucket loaded with copper and an aquarium bubbler to keep things flowing. Yesterday was the 5th day evaporating being down to the last four liters of solution left. I have about 2.5 liters left now and have been testing the solution periodically with stannous which will give a false positive of agcl I believe because when I add HCL to a small amount of the solution no white cloud of agcl can be seen.

Just a note about adding stannous chloride to a concentrated copper nitrate solution.

I think the reason you are seeing a white precipitate is that the Cu²⁺ is reduced to Cu⁺ by the stannous chloride and precipitates as CuCl which is only slightly soluble in a nitric solution. It could also be a reaction from tin nitrate which I believe (haven't looked it up yet) is unstable and forms metastannic as a precipitate.

Göran