do you think i manage to remove lead that way

[ericrm]

quote...kadriver said...---Re: Just Finished my FIRST ever GOLD BAR 1.025 Troy Ounce
I may take Harolds input and re-refine the bar.
In Hoke, there is a proceedure that removes lead.
It seemed rather lengthy, but appears worth it.
Hoke says to add sulfuric acid to the aqua regia and EVAPORATE it down to syrup.
Then add hydrochloric. It says that this removes excess nitric acid
Plus it removes LEAD.
I will study this process some more and get everything strait.
Then I'll set up to refine the bar again to the proper purity.
Thank you for your help.
I welcome all criticism. I am very interested in getting it right on.
kadriver------------

i dont add sulfuric acid so theorically i should have lead in my gold but i think i remove it efiently(i have no way of testing)

this is how is process
first the recovery ap,ar,hcl/cl,even hcl/h2o2(witch i discover is more a pain than anything)
i remove the big scrap with coffee filter(except for the big stuff i dont filter anymore)
then precipitation smb or copper (depending on how much dirty my solution is... if i cant see it change color i take copper)
recovery ended-----------------------
first refine--------------------
i put the powder inhcl/cl (to me its simple ,no denox)
i leave it on the side in a beaker full of dirty precipitate (i dont filter anymore gravity is better for small particle than my coffee filter)
when everything is down a week or two,or month? :shock: (i then siphon the upper clean part in a clean beaker )
precipitate with smb (usualy my solution is very clean yellow or slight lime green)
in the same beaker i wash in hot hcl
1 refiene ended -----------
2refine---------------
the gold is still in the same beaker
i dont change hcl i add more(at this point hcl is always light yellow indicating me that i have copper in)
i add clorine and disolve gold
i precipitate with smb
i suck out most of the solution
in the same beaker i wash powder with hcl 1 time than 2 time with hot demineralised water

since lead is soluble in hcl,copper chloride and copper oxide too, working this way ,do you think i am ending with a clean result free of lead

also i idnt put all the step of testing with stannous chloride ,the smell test, the visual test ...i just put what is necessary to understand how i work and where i could have made mistake

 

[Harold_V]

quote...kadriver said...---Re: Just Finished my FIRST ever GOLD BAR 1.025 Troy Ounce
I may take Harolds input and re-refine the bar.
In Hoke, there is a proceedure that removes lead.
It seemed rather lengthy, but appears worth it.
Hoke says to add sulfuric acid to the aqua regia and boil it down to syrup.

Please refrain from making comments such as this. One DOES NOT BOIL when evaporating.

How many times must I post this admonition?

We strive for accuracy on this forum. If you guys persist in discussing evaporation by making reference to boiling, I'm simply going to start deleting your posts when you do. This has to come to an end, for all you're doing is promoting a troublesome process, undoing any possible good I may have done when trying to correct misinformation. I consider that a waste of my time.

Do NOT quote any article that make reference to evaporation by discussing boiling. Do not post on evaporation, including the word boil, unless it is to suggest that one should NOT boil.

If readers know of anyone dispensing information on evaporation (via the board) and is talking about boiling to accomplish the process, please let me know. I want that information killed, and immediately.

Harold

 

[ericrm]

well
since nobody seem to have an answer i have thinking a little more and come to what i think is the good answer...
even if lead chloride is soluble in hcl ,it not mather how many time i wash it i will only reduce the % of it in my gold...
so i dont have the choice and add a few drop of sulfuric acid before i let my solution settle
it is the only way to be sure to remove 100% of it

 

[Geo]

when you add sulfuric acid, the lead will precipitate as lead sulphate which is soluble in water. hot water will remove the lead sulphate on your first rinse.

 

[ericrm]

thank you geo
i always read to put afew drop of sulfuric acid but do you know how much is realy needed to have a quick reaction?

 

[Geo]

unless you have more than a trace, just a couple of drops will work. stir with a glass rod.

 

[qst42know]

when you add sulfuric acid, the lead will precipitate as lead sulphate which is soluble in water. hot water will remove the lead sulphate on your first rinse.

Lead sulfate precipitate needs to be filtered out it is not very soluble.

 

[Geo]

it should dissolve in boiling water, shouldnt it? that should be part of the first rinse if he is doing it right.

 

[ericrm]

geo i will add the sulfuric acid at the beginnig of my first refine ,so it will settle with the rest of the crap...i just hope it sink fast...

 

[qst42know]

it should dissolve in boiling water, shouldnt it? that should be part of the first rinse if he is doing it right.

I believe you are thinking of lead chloride being soluble in hot water.

 

[JTroyner]

Would battery acid (not sure of %) be sufficient to precipitate the lead out? That's all I have on hand right now.

 

[qst42know]

Yes, battery acid is fine.

 

[ericrm]

i would think yes but you had to put more,how much more ... 3 time what you would use from concentrate acid...

 

[JTroyner]

Thanks guys, I used it and it worked great. I'm amazed how much dissolved lead it dropped.. 8)

 

[Harold_V]

when you add sulfuric acid, the lead will precipitate as lead sulphate which is soluble in water. hot water will remove the lead sulphate on your first rinse.

Nope! Lead sulfate is not soluble, so it is removed from the solution in filtration. Lead nitrate, on the other hand, is soluble in hot water.

It is advised that a few drops of sulfuric acid be added to all lots of gold being processed. It does no harm, and ensures that lead is eliminated.

Harold

 

[Geo]

thanks qst42know, and thank you Harold. sometimes i speak out of turn without looking at my notebook. i guess the reason i didnt remember the difference between the two is i add a little sulfuric to my solution before i filter the first time so i never had an issue with it. i suppose if i had a problem with it i would have known which was which.

 

[kraguj]

Does sulphuric acid precipitates the lead only from AR solution, or in similar way it can drop Pb from AP or HCL+Cl solution?

 

[butcher]

A few drops of sulfuric acid could be added to Copper II chloride solution (Acid Peroxide), or to the hydrochloric acid and bleach solution,
but lead in these solutions becomes lead chloride, and lead chloride is not very soluble, even in these acids, so the lead would report as white powder in the bottom of the vessel, when you let it sit, traces can also be filtered out of solution, (silver can also be in the white powders if it was involved), (you can separate the silver and lead chlorides with boiling hot water, lead chloride slightly soluble in boiling hot water silver chloride is not).

Aqua regia lead chloride is also insoluble, but I suspect just like silver chloride AgCl, in which a portion of the silver picks up an extra chloride to form AgCl2, and becomes soluble in the very strong acid of aqua regia, lead may do something similar, and the a portion become soluble in the very strong acid.

I do not worry about the lead in Copper II chloride solution (It is tin that I hate in the solution), and I have not had trouble with lead in the hydrochloric acid and bleach method, but then again I let the solution settle very well, normally in cold weather or through cool nights, Decant and always filter solutions, also I will refine twice, and I normally try and remove as much lead chloride before I dissolve any gold, so your’s and my mileage may differ if we both drive differently, and I can be wrong but I do not believe the lead carries through this process, as easily as it does in the very concentrated acidic aqua regia solution, HCl/NaOCl solution is not very acidic, and usually fairly dilute.

You can try a couple of drops of sulfuric next time and see if you get any lead to precipitate, it will not hurt anything, but I also suspect not much lead would be found if you let solution sit well and let powders settle, and filtered solution (then try your H2SO4), if you find lead at this stage report back and let me know.

Also if you have a lot of lead at this stage I would also look into better methods for eliminating as much of the lead as you can prior to dissolving the gold.

 

[Geo]

if lead is a problem in these solutions, it is easy to see as lead chloride makes a very distinctive needle like crystal. if you see needle shaped crystals, it is most likely lead.

 

[kraguj]

Thank you Butcher and Geo,
it is imposing how much knowledge and practical expirience can be found at this forum!