Stock pot question

[MrCrusher]

Hi Everyone,

I am a noob at processing and have a question about my stock pot.

So far I have had to empty it out 4 times. I have changed the material I process from
99% Escrap to 100% gold filed.

I just emptied my stock pot for the 5th time and it has a White coating on the bottom.
( it has always been black before)
It was very light material as I was sucking some out in my siphon.
I have let it settle out good in my 2nd pot and wanted to figure out what it was.

What would be the best way to determine just what this white material is?

Any and all suggestions are welcomed.

Thanx
Mr_Crusher

 

[rewalston]

That white material could be Copper (1) Chloride, lead Chloride, or even possibly silver chloride. Take small samples. In one add some HCl, if it dissolves and turns green it's copper (1) chloride. In the second add boiling water if it dissolves it lead chloride (if it doesn't dissolve it's probably silver chloride. If it's silver chloride you want to keep it wet so that you can process it later to recover the silver. But I could be wrong. Best to let others chime in on their opinions.

Rusty

 

[4metals]

My guess is you are now processing gold filled so you are using a nitric/distilled water to digest your material to separate the solubles from the insoluble gold. Is this nitric/distilled water what you are cementing in your stock pot with copper? If you are cementing on copper the solids dropping out will be metallic silver, gray not white.

It is my guess you rinsed everything into your stock pot with tap water, hence a source of chlorine, and formed chlorides before the silver had a chance to cement on the copper. It could also be lead chloride, as gold filled has all sorts of surprise metals in it, so you should test it as Rusty suggested.

 

[MrCrusher]

Well more to the story.

I siphoned off my 2nd settled pot and left the whiteish substance in the bottom.
I had already added some base to get the PH up some for cementing out the copper.

My white substance is now light brown. It dissolves in cold water.

From what was said here I am guessing this is some form of lead chloride?
If so how can I keep it from forming in my stock pot? Only use distilled water in everything?

Thanx for all the advice
Mr_Crusher

 

[g_axelsson]

To get rid of lead chloride the standard way is to add a bit sulfuric acid. This will form a lead sulfate precipitate and can be filtered off.

Personally I would not bother, there should be scrap metal in the stock pot and when harvesting the sludge I would expect it to contain garbage from the scrap metal. I add a few drops of sulfuric acid to my gold chloride before filtering, that takes care of lead chloride (as lead sulfate) together with any silver chloride.

To get back to your dissolved brownish substance, add a few drops of sulfuric acid to it. If it is lead chloride then it will form a white precipitate of lead sulfate.

It would be easier to give an answer if we knew exactly which liquids you put into your stock pot as well as what kind of metal you use.

Göran

 

[MrCrusher]

Goran

As far as metal I have copper in my stock pot. I also use the copper heat sinks from CPU's which have a NI plating on them. They also have the gold coating where they were soldered to the cpu die and a little remaining solder. Just what I get from the material I run according to 4Metals it could be anything.

As far as liquids I put in, it is just the left over solutions from the processing of gold filled material. I use Harold's gold filled process which only includes Nitric, Hydrochloric, and distilled water, I also add a few drops of sulfuric before filtering for the lead removal. I do however rinse some vessels with tap water from time to time so that could be a source of chlorine. . . Actually I now remember on one batch on my 2nd refinement I did a dissolve with bleach. so the stock pot did get a fair amount of chlorine added. on this last cleanout. Could that be the cause of this white substance?

Before I change out the Stock pot I place some bright copper wire and bubble it for 2 days then let it settle for 2 days.

I hope I understood your question correctly and answered with what you wanted to know. If not let me know and I'll try to add any missing information.

Thanx
Mr_Crusher

 

[g_axelsson]

I use Harold's gold filled process which only includes Nitric, Hydrochloric, and distilled water, I also add a few drops of sulfuric before filtering for the lead removal.

I do however rinse some vessels with tap water from time to time so that could be a source of chlorine. . . Actually I now remember on one batch on my 2nd refinement I did a dissolve with bleach. so the stock pot did get a fair amount of chlorine added. on this last cleanout. Could that be the cause of this white substance?

Before I change out the Stock pot I place some bright copper wire and bubble it for 2 days then let it settle for 2 days.

I hope I understood your question correctly and answered with what you wanted to know. If not let me know and I'll try to add any missing information.

Thanx
Mr_Crusher

Yeah, that narrows it down a bit.

Maybe the hydrochloric acid could be a source of chloride ions...

I wouldn't loose sleep over this. As you said it was soluble in cold water, so just add a bit more water to the stock pot. Maybe the solution is getting too concentrated by evaporation. In any case if you have tested the solution in the stock pot and it's free of values then the white salt would also be free of values.

You already have sulfuric acid in the solution but it might be used up by an excess of lead so you could still test the solution with a few drops of sulfuric to see if it is lead chloride.

Göran