TLDR: sorry for the long post below. If you want to read a long story just skip below please. Sometimes details help. Long story short, processing nitric wastes from gold filled junk left behind some black sludge. I treated it with a few different methods including an AR boil, recovered some PMs, and rinses with distilled water turns it white. Assuming it's silver chloride, used lye to turn it black but no amount of sugar will turn it gray. What should I do with this mess to confirm I've squeezed the values out of it?
The Whole Story
I am processing some first-step wastes from a few kilos of gold filled material including eyeglasses, which are pretty steel-heavy and have a lot of contaminants.
When I do my nitric boils, I pour the solution into a couple 2L beakers loaded up with sterling to use up the nitric, then when they clarify I pour them into copper-laden 2L beakers for cementation. I try to avoid transferring any solids but some go over inevitably.
The waste stream is typical from there.
When I was done with this (obviously I'm a small operator) I retrieved the slimes and solids from the bottom of the silver-laden beaker. It was dark and sludgy. I assume I didn't accidentally decant any chloride solution but I wouldn't bet the farm on it.
I decided to clean it up but distilled water turned it into something like black paint and I couldn't get it to clarify. I boiled with AR to try to remove anything I could but it was still very muddy. I finally put it in a Buchner funnel and washed it, winding up with a contaminated-looking filter of silver chloride (white chloride with little black chunks). The liquid was positive for PGMs.
I did one more nitric (only) rinse on the solution and seemed to get some copper out, while the white stuff all turned black again. Rinsed again and it turned white again with some blue solution on the top. I have maybe 2-3 ounces of material.
Here's where it got very weird. I added sodium hydroxide - the solution briefly started to boil up but immediately went back down and I got a very quick black color response. Cool. Waited a few minutes and began to add sugar to the mixture which is approx 1L now and includes some rinse water. No boiling was observed (some heat/steam) and no color change to gray. I thought I might be fighting too much sodium hydroxide so I went ape with the sugar. Then I divided my batch, pouring off the thinner stuff from the top and keeping the sludge on the bottom, and again went ape with the sugar.
All I wound up doing is making cupcake frosting for Bender (Anyone a Futurama fan?).
The rules of solubility in the library made me wonder if I have a lead salt (e.g. PbCl). I'm also wondering now if I have anything worth going after, since I boiled it with AR.
Before I dry and dispose of this horrible stuff, have I missed any recovery opportunities?
Thank you in advance for your insight!
The Whole Story
I am processing some first-step wastes from a few kilos of gold filled material including eyeglasses, which are pretty steel-heavy and have a lot of contaminants.
When I do my nitric boils, I pour the solution into a couple 2L beakers loaded up with sterling to use up the nitric, then when they clarify I pour them into copper-laden 2L beakers for cementation. I try to avoid transferring any solids but some go over inevitably.
The waste stream is typical from there.
When I was done with this (obviously I'm a small operator) I retrieved the slimes and solids from the bottom of the silver-laden beaker. It was dark and sludgy. I assume I didn't accidentally decant any chloride solution but I wouldn't bet the farm on it.
I decided to clean it up but distilled water turned it into something like black paint and I couldn't get it to clarify. I boiled with AR to try to remove anything I could but it was still very muddy. I finally put it in a Buchner funnel and washed it, winding up with a contaminated-looking filter of silver chloride (white chloride with little black chunks). The liquid was positive for PGMs.
I did one more nitric (only) rinse on the solution and seemed to get some copper out, while the white stuff all turned black again. Rinsed again and it turned white again with some blue solution on the top. I have maybe 2-3 ounces of material.
Here's where it got very weird. I added sodium hydroxide - the solution briefly started to boil up but immediately went back down and I got a very quick black color response. Cool. Waited a few minutes and began to add sugar to the mixture which is approx 1L now and includes some rinse water. No boiling was observed (some heat/steam) and no color change to gray. I thought I might be fighting too much sodium hydroxide so I went ape with the sugar. Then I divided my batch, pouring off the thinner stuff from the top and keeping the sludge on the bottom, and again went ape with the sugar.
All I wound up doing is making cupcake frosting for Bender (Anyone a Futurama fan?).
The rules of solubility in the library made me wonder if I have a lead salt (e.g. PbCl). I'm also wondering now if I have anything worth going after, since I boiled it with AR.
Before I dry and dispose of this horrible stuff, have I missed any recovery opportunities?
Thank you in advance for your insight!
