Confused As to what process to use

[Rizingfire]

Ok, so I have been reading a lot at Gold n Scrap, a website that is linked to several videos supposedly made by people from here...anyway I have some heavily covered circuit boards that test above 18k and less than 22k. Anyway I followed the video with the aqua regia and end up with a greenish liquid. I tried adding ice to get any silver out but nothing happened. So I put SMB in and it fumed a crazy red gas but nothing precipitated.

Am I using the wrong process? Is there something else that I am supposed to be doing or what am I doing wrong?

I heated up the HCL and added nitric til the process stopped and there was no gold left, put ice in it to drop any silver but nothing happened...however the video says, the next morning and shows it being filtered yet says to filter it while it is still cool, how is that possible to filter the next day and filter it while it is still cool? The video just made it more confusing and I don't want to lose any more and the test batch obviously seems salvageable so before I go any further with this one I wanted to ask what to do....so I have the dark greenish/blue aqua regia in a jar and noit sure what to do now since adding smb didn't drop anything last time...course last time I didn't have a burner so I was using hot water (125 degrees F) to heat it...but this time I used a burner...any help will be appreciated...

 

[philddreamer]

Hi Rizing!

Have you read Hoke's yet?
You MUST first read Hoke's before any attempt on recovery &/or refining.
Have you done some searches on the type of boards you have & the proper process to use?
What type of boards did you process? Maybe AP would have been the proper process for your boards, & not AR. SMB fizzing & brown fumes means too much niric still present in your solution, that could be the reason for no precipitation.
Did you stannous test your solution to make sure there's gold in solution? If there's no gold in solution, all the SMB in the world will not precipitate any gold.

You should safely put away your solution & read Hoke's, also do some searches & learn the proper procedures & safe handling of the chemicals.

Take & be safe!

Phil

 

[ericrm]

Am I using the wrong process?

yes you are :lol:

well let see what i have learn here ,i will take it as a test like in school
first AR is rarely the best process for board... you should have used AP... CHEAPER EASYER

first have you tested with stanous chloride yes or no???
if no: when dealing with board they always have copper under the solder mask that will cement gold out,they is a possibility that you have no gold left in solution....
if yes ,i assume gold is still in solution.

I heated up the HCL and added nitric til the process stopped and there was no gold left, put ice in it to drop any silver but nothing happened...

since hot acid react faster and there is always a risk of boil over with AR ,I would not recommend to heat your acid,also chemical reaction usualy make some heat...
silver in AR make silver nitrate witch is then automatiquely converted (if enuf hcl)in silver chloride ,witch is insoluble in hcl... so you CANT precipitate it with ice ,it as already been precipitated.

So I put SMB in and it fumed a crazy red gas but nothing precipitated.

i hope you have a fume hood and not a mask to protect yourself from the NOx
i dont know what is the chemical reaction to it ,but that have done so ,because you still have free nitric in your solution of AR.you should have eater kill you nitric with urea (witch will make amonia reason for why i dont personnaly use it) or evaporate it to a sirupy state ,than add hcl ,evaporate it down until you have no more nitric present. OR to me the best thing to do,ciment your pm out using copper.
to see if you still have nitric present you can use a prill of urea to see if any reaction(buble /feezing occur)

so I have the dark greenish/blue aqua regia in a jar and noit sure what to do

what can you do?
you could remove your nitric ,than precipitate with smb thats a possible end
you could cement everything with copper than refine it twice (by the way since it is board you probably have lead in it)you will be able to deal it with a few drop of sulfuric acid ,when your gold powder will be disolve the next time

what you should do? stop looking at video and start READING...................................................................

so what you think did i pass my exam

 

[Geo]

ericrm,A for effort but you lost a lot of points on spelling. you really should use spell check. Google toolbar has it and Google Chrome has it built in.

Rizingfire, you need to spend some time reading the forum. download Hoke's book and read it a couple of times, at least until you understand what you are doing. are you being safe with this? i can tell you from personal experience that NOx fumes will destroy your health. if you can smell it then its too much. read the guided tour before you do anything else. if there's no talking you in to waiting, then you should use eric's advise and cement any gold in your solution with copper.do this outside, just put a piece of copper pipe in the solution and leave it there for a couple of days. any powder that comes out will be your gold IF there is any in solution.

 

[samuel-a]

Rizingfire

You have been using a process which do not fit to your starting material.
The process showen in the video relates to high karat gold. Which means solid alloys ranging from 18 - 24K jewellry or gold nuggets/placer.
It was never suggested as a way to process boards...
Gold in electronics is usually plated ontop of a nickel layer ontop of a copper layer, silver may sometimes be found in solder, but that's rare in new electronics.

Phil is absolutely correct in his response. Read Hoke, learn how to test with SnCl research your boards before hand.
It is globally recommended around here to first treat the base metals under the gold plating (copper, nickel, lead and others)and then dissolving the gold.
There are some exceptions such in cases where the base metals to gold ratio is high enough and base metals composition allows for a direct dissolution of all metals by AR, such in the case of ceramic cpu's...

So, in the case you are in, indeed a test with SnCl is needed, and if positive for gold, cement all with copper slab.



ericrm,

It has been well established by our resident experts and proven by myself and others to be true.
AgCl is soluble both in HCl and H2SO4, as it exist in equilibrium (between solid state to aq.), the greater the concentration of the acid, the more AgCl(aq) is in solution.... also effecting this equilibria are temp' and presence of an oxidizer which shift it to the right, meaning more AgCl in solution.
With the lack of an oxidizer or a minimal amount of it left in the AR, temp' is the only variable lefft to deal with, as you cool the solution to around 5C, the solubility of AgCl drop to near zero and precipitating it back... this takes some time to happen though.

All in all, the solubility is very low, reaching to about several grams to one liter of hot concentrated AR...

GSP had suggested to filter AgCl out, right after the addition of ice...I have suggested to add ice, dilute and leave for the night and let it go back to room temp... In both cases most of AgCl will be removed.
It is pointless trying to decide which way will remove more silver as we talking about very small differences, and the gold in any case is being re-refined.

what you should do? stop looking at video and start READING...................................................................

Had you botherd READING you would have known that.
My videos, in most cases are a visual presentation of a fully detailed WRITTEN text... you can look it up in my site, it's called "high karat refining P. - 1,2)

Also, i could not imagine any refining operation, even the smallest one, not using external heat source to drive reactions.
With the proper techniques and precautions employed of course, it is plain silly not to use heat.

 

[goldsilverpro]

Rizingfire,

First of all, the purity of most all gold plating on electronics is very close to 24K.

Secondly, none of this gold is solid. At most, it will probably be about .000030" thick.

Thirdly, you can't evaluate gold plating with XRF, unless it is set up to determine plating thickness and you have accurate standards. Also, you can't evaluate gold plating with a touchstone or one of those testing pens. The results you get from all these are 100% meaningless.

Fourthly, it's obvious you know absolutely nothing about what you're try to do. If you keep messing around, someone is going to get hurt. Do yourself a favor. Stop everything and spend at least a couple of weeks reading and studying. Then, you'll be able to ask intelligent, specific questions. No one is going to hold your hand from start to finish. At least, I hope no one does.

 

[goldsilverpro]

Sam, you said,

GSP had suggested to filter AgCl out, right after the addition of ice...I have suggested to add ice, dilute and leave for the night and let it go back to room temp... In both cases most of AgCl will be removed.

If you're going to dilute anyway, I see zero difference in your process whether you add ice or not. The ice lowers the solubility of the silver chloride in the acid. To take advantage of this, it must be filtered while very cold. Otherwise, the silver chloride will re-dissolve in the acid as it warms up. Except for that precipitated by the dilution from the melted ice, you will essentially end up with as much AgCl dissolved as when you started. Not counting the extra dilution you did, if you add ice, then let everything come to room temp and filter it, you could have accomplished exactly the same thing by first melting the ice you were going to use and then adding that water to the solution.

In general, I would either add ice and filter the solution as cold as possible or just dilute 3 times and filter. The only improvement (maybe?) I can see would be to dilute 3 times, then chill with ice and filter cold.

 

[Geo]

if your going to have AgCl anyway, why not add NaCl to the solution and filter.

 

[Claudie]

If you have red fumes from Nitric acid, I really hope you are following safety precautions. Those fumes can be deadly. If getting a lot of Gold from computer boards was easy, everyone would be doing it. Please follow the advice these guys are giving you before it's too late. Inexperienced eyes will always see heavy, solid Gold everywhere they look on a circuit board, but it's just not really there. :|

 

[Harold_V]

if your going to have AgCl anyway, why not add NaCl to the solution and filter.

Aren't we discussing a gold chloride solution? Please correct me if I'm wrong.

Assuming I'm right, what function would NaCl provide that hasn't already been provided by the HCl used to dissolve the gold?

Harold

 

[samuel-a]

Harold, i think Geo wes referring to the solubility (or in-solubility) of AgCl in acidic medium.

In that case, adding NaCl will increase Cl^- ions concentration and leads to higher solubility of AgCl. IMHO.