help with AR

[robert_93030]

my first try was 1 ounce of pin scrap with 30mil of nitric and 90mil of cloric i let it sit overnight very little was left i put the solution into different beaker and green solution tested + for gold i then bolied water and mixed in some urea once the urea was disolved i began to pour in little by little till the foaming stopped then i bolied water and added storm once disolved i began to pour in little at a time very little foam i then began to see the green solution start to turn amber brown gave it about an hour now half the beaker is amber, bottom half is green i added more storm waited overnight i come to fine the beaker now has aqua blue solution? test for gold and nothing, at the bottom of the beaker there is no "mud" but i do find lots of white sand and a bunch of "white starfish" what did i do worng?

my second try i used 1 ounce of pin and two intel processer's nothing left but the cerm processor's did the same process as above but this time insted of auqa blue is was orange?

is it better just to refine scrap jewelery then to hassle with cpu stuff?
does anyone know the AR recipe for 1 ounce of scrap?

 

[qst42know]

1 ounce of pins has very little gold. It is easy to loose small quantities of gold in dirty AR.

Use nitric or HCL+peroxide alone to remove as much base metals as you can first.

 

[robert_93030]

so i should use nitric first to remove all non-gold then filter and put solids in a AR batch?

 

[Harold_V]

That's correct. In cases where you have copper based alloys under gold, it isn't a good idea to dissolve everything with AR. Get rid of base metals first, so you don't have such a dirty solution to work with, plus you don't risk losing gold to cementation on un-dissolved base metals.

Get a copy of Hoke's book and read it. Don't process anything more until you understand the reasons these things are recommended. You'll be happy you did.

I also encourage you to explore the work-arounds presented in this forum for eliminating base metals without the use of commercial nitric acid. If you have a ready source, that isn't important, but most folks don't have, and those that do are paying impossible prices.

Harold

 

[Rag and Bone]

Robert, you have the right idea experimenting with a small batch. Trouble is...it get's tough when you have very tiny amounts of gold to recover. I recommend getting at least a dozen or so ceramic cpu's or a 1/2 pound+ of clean, gold fingers to start with (if e-scrap is your interest/opportunity).

HCl-H2O2 (AP) is great for stripping gold from e-scrap.

Be sure to dig around old posts for info. It's out there, sometimes hard to wade thru... AP has been discussed in depth on the Forum.

Be sure to save your failed batches and "waste" solutions. All those traces will build up over time and you can recover them in the future.

 

[Oz]

Rag,

I agree with you except I would offer the caution of AP with CPUs with iron, and aluminum without separating the components.

For what it is worth I think the best thing for someone to start learning electronic scrap refining on is fingers in AP. Once they understand that process start to finish they will be in a better position to understand the extra copper and other elements in pins. This then translates directly to the variations in CPUs. In my opinion this introduces them to the greater contaminates of elements and their complexities incrementally.

 

[butcher]

Robert this may work to recover your gold, try dropping a little copper piece of wire in your aqua regia boil hard to syrup, add water to dilute, see if you get a brown powder of gold and copper Etc. , remove and test liquid, now this powder either add this to your next batch, or remove copper with dilute nitric, decant liquid , then add new Aqua regia to your powder to redisolve and precipitate your gold with ferrous sulfate,or SMB, dont use too much acids, but make sure to use enough to disolve the metals.
you mentioned using storm as a precipitant I don't know what that is some companys name for $$ can be bought elswhere? for alot less?
look into Using SMB sodium metabisulfite, or making ferrouus sulfate, or sodium sulfite.
Aqua regia recipe 4.5 HCl + 1 part nitric acid, but not for base metals with your gold, and nitric needs eliminated, read up on boiling it out and HCl to wet. also read up on HCl bleach alot of times with electronic scrap it is actually easier to use than Aqua regia (no nitric to deal with) and cheaper.
looks like you have your work cut out for you with all of this studying.
just remember gold never comes easy, otherwise it would not be precious.

 

[robert_93030]

i have taken all the pins off the processers im going to give them a nitric bath tomorrow then i will clean it up with DI water and remove any junk thats left in i should only have pins left? Then saturday i will drop the pins in a AR batch. does 30ml of nitric and 120ml of chloric sound good? i will take pics.

 

[EVO-AU]

Hey Butcher:

Just found this abstract and thought you and others might be interested. Rather lengthy, but a different approach Ph - wise.

Document Type and Number:United States Patent 3856507
Abstractisclosed is a method for recovering gold from solution in aqua regia by adjusting the pH of the aqua regia solution to in the range

Phill

P.S. Butcher - Storm ppt is put out by the I.Shor Co. Look it up, but it is not worth the key punching.

Phill

 

[goldsilverpro]

Interesting patent, EVO. By simply raising the pH of the aqua regia to 2.5 to 3.0 with NaOH, the gold is dropped out with a sulfite. No urea. No boiling down. The examples in the patent had no base metals present. They started essentially with pure gold. If anything precipitates during pH adjustment, I guess it could be filtered out before using the sulfite.