MB125 processor & PCB

[ander]

Has anyone met that IC? It seems very promising. I processed one but I got only 40mg of Au, seems much less than expected. I have all PCB with that- set of 8 pcs and 8pcs of smaller processors in white ceramics. I wanted to remove Sn and Pb solder first so I put them into 30% nitric acid. Partially dissolved pins- I found no gold underneath solder. Black residue on the bottom- gold was dissoved in solder? One of ICs had a tiny hole in the heat spreader and acid dissolved the plate, but underneath the gold plating- look very thick, there is another layer of greyish-white metal. What could it be?? As you see on the attached picture(left- middle), wires are white, not yellow. Palladium?

 

[samuel-a]

how did you removed the core (silicon waffer)?

 

[ander]

I used traditional method- be nice and if it doesn't help- be naughty . I broke the proc to remove the heat spreader. Firstly I thought it was soldered so I put it into flame- no reaction. Supposedly heat helped a bit to gently remove core after breaking IC just with knife. As you can see gold on top has a crystal- like structure. Chemically deposited?

 

[ander]

HOORRIBLY diappointed. Only 0,24g from 6 procs. I had problems with pH adjustment, then with using SMB- too low temperature at all. After 24 hours solution became dark blue. Glod settled on the bottom as powder and also as mirror on beaker glass. All gold powder was melted with borax- lot of impurities. After the christmas I get back to work to find where the gold did go.

 

[Harold_V]

HOORRIBLY diappointed. Only 0,24g from 6 procs. I had problems with pH adjustment, then with using SMB- too low temperature at all. After 24 hours solution became dark blue. Glod settled on the bottom as powder and also as mirror on beaker glass. All gold powder was melted with borax- lot of impurities. After the christmas I get back to work to find where the gold did go.

I saw no comment on washing of the gold powder. If you thought yourself clever and skipped that part, no need to go looking for your lost gold. It will be found in the flux you used.

If you'll read Hoke and follow the instructions that are so clearly stated, none of these things will be a problem.

I don't know if anyone is tired of hearing me say so, but I'm getting tired of endlessly repeating myself. Gold that is clean will melt perfectly well without flux. If you need flux to melt gold, it is my recommendation that you look at the processes you choose to use----you can do better.

Harold

 

[ander]

Of course I washed my powder- seems so obvious I did not mentioned that. Some of Au lasted on beaker glass surface too. No, I'm not tired about being corrected. I hope you are not tired to correct others all the time .

 

[Harold_V]

Of course I washed my powder- seems so obvious I did not mentioned that. Some of Au lasted on beaker glass surface too. No, I'm not tired about being corrected. I hope you are not tired to correct others all the time .

Good. That may minimize part of the problem. If, however, your loss is by flux, that's a whole different problem.

Gold that sticks to the vessel in which it is precipitated can be removed using a plastic policeman. If you have one in good condition, it will wipe the sides clean. I did experience traces of gold sticking to the policeman, however, but that got wiped with a small piece of paper towel, which was stored until I had a generous amount to incinerate. The resulting ash was then dissolved directly in AR for eventual recovery of the gold involved.

The idea of fluxing isn't as bad as I portray, but if the gold that is melted is mixed with flux, there's more than a good chance it will melt and never agglomerate totally. Once the prills are absorbed by the flux, they can be difficult to recover. I'd seen that a few times when melting cement silver. I learned to melt without flux, than to add to the top only, and then only after the silver had started to flow. It then would pick up oxides and clean the metal from the top down. That, for the most part, eliminated losses to the flux.

In order to recover lost values in flux, it's often necessary to melt the flux with a thinner (fluorspar, for example), plus to use a collector of sorts.

Repeating what may be covered in Hoke tends to wear out its welcome, yes. Besides, its a gross example of one that wants instant gratification and expects others to do for them what they should do for themselves, which is to learn the fundamentals of refining.

One of the hardest things I've found is getting readers to pay attention to her book, yet once they actually read it, they understand why I am constantly nagging. Those of us with experience can spend countless hours daily, repeating information that is readily available to the masses with just a little bit of effort. That saves time for problems that are out of the ordinary and may deserve special attention.

I think you'll find, at least at first, when you have not established good work habits, that you will be inclined to lose a little gold. It's not lost in the sense that you no longer have it, but it gets separated from the main lot and can be difficult to recover directly. It is for that reason that those that refine must learn to never toss anything. Scraps of paper that contact gold, even in solution, are incinerated and processed for values. It may not seem like much, but in the long haul, a great deal of value is recovered. I used to incinerate my gloves when they were no longer serving their purpose.

Harold

 

[butcher]

Harold your advice here on the forum is invaluable. you probably do not realize how many you help, not only to produce pure gold, but you help us in many way's. keep up the work.

 

[Harold_V]

Harold your advice here on the forum is invaluable. you probably do not realize how many you help, not only to produce pure gold, but you help us in many way's. keep up the work.

Thanks, butcher.

Don't sell yourself short in the process. I read all of your posts and am constantly amazed at your ability to understand things from the technical end. I'm basically a moron, but a moron with a lot of refining experience. I learned everything the hard way, including coming to terms with the idea that Hoke knew what she was talking about.

Ok, I admit, some of her "guidance" seems more like a death sentence (tossing gasoline liberally on your incinerating wastes, for example), but I can't think of a better source for anyone, aside from well educated chemists, to learn the fundamentals.

It is comforting to know I reach others. I spend a lot of time on this forum hoping to make a difference.

Harold

 

[butcher]

You do make a difference, I like many here we study (Harold) like you studied (Hoke), you also help us build character, I feel what Noxx started you carried. this would not be the greatest gold forum ever, in the whole wide world with out you. thanks for you hard work and time you invest here.

 

[ander]

O.K. I see discussion went off-topic. I want to be clearly understood- my complaint was not about shortage of knowledge, claiming "teach me now!". Being an engineer means have the knowledge. I am certainly not 5yo boy to ask everyone to teach me things. I can do this by myself. My problem is being little 'messy'. I know that. I complained about the yield which obviously seems too low for me. But according to my previous tries with much easier materials to refine- pins, the yield seems reasonable. Being disappointed is my personal feeling and has nothing in common with objective knowledge about amount of gold in these procs. I suppose many others people would be very happy getting things I got. It's my 'traditional' ethnic Polish way of improving things. If you do not complain there is nothing to do better way...

 

[jimdoc]

I always keep the soldered ones separate from my clean processors because they can be a hassle. Actually I have been saving them up to deal with later.In one batch I did all the gold turned into a fine purple cloud in my bucket, like a giant stannous test. I haven't messed with any more since then.
Jim

 

[butcher]

sorry for getting off topic just trying to let someone who has gave so much to this forum Know his effort is apreciated.

 

[ander]

I absolutely have nothing against off-topics. I appreciate Harolds work much too. But I want to focus on yield and method for these procs. Maybe someone will need these information some time. Relax and wait until I make my process completely and give you the total yield .

 

[ander]

As (suppose) Harold wrote once- that made his wisdom the hard way. Only those, who do nothing make no mistakes. Everyone can get 'eclipsed'. I did stupidest thing I could. So did I. Yesterday I got another portion of gold precipitate, after melting like 0,16g of- I suppose- 12-14K red gold (comparing to my wifes jewelry). Instead to concentrate leftover solution with sodium borohydride to get few grams of metals I cemented it with zinc powder, having knowlege what is about to happen at filtering and washing!!! I 'smelted some of that stuff and dissolved in muriatic, solution is milky- silver and lead chlorides do not settle down. The idea was to alloy all metals together. Now I don't know if I could just oxidize zinc gently and dissolve in sodium hydroxide or to continue with muriatic- which is much more valuable for me. I KNOW I SHOULD HAVE ASKED. It's just my stupid nature of getting hurry. The irony in that all is that I'm simply getting "gold rush". I made 3 small test gold recovers with good results, after scaling up and having a bit of experience I FAILED. It's always like that. Have to switch my attitude.

 

[butcher]

can you repeat your question, maybe wording it differently.
I am not sure I understand what you are asking.

from what I gather you had a solution, and used zink to cement out metals, these would be all the metals below zink in the reactivity serie's that were in solution.
then you say you smelted what was your flux? and I suppose you got a metal bead or beads of melted metal.
then you say you disolved these in muratic acid, if they dissolved in muratic alone the liquid should not contain gold, unless there is some type of strong oxidizer, it would be insoluble, ( and if these smelted beads did dissolve did you use heat? any insolubles incenerate and refine, or save.
if you have a concentrated muratic very acidic solution it could have some lead and silver in it, boiling off excess chlorine, then dilute (add NaCl salt if needed) it will precipitate any silver, if it still holds lead you can add a little sulfuric to precipitate lead as sulfate.
zink would disolve easy in HCL.

 

[ander]

Actually I used wrong word, not checking its meaning in english. I tried to alloy zinc powder with deposited metals. I did not used any flux. Melting failed, but I got rid of sulphur and nitrates- that was one of purposes. Then I dissolved partially oxidised powder in muriatic acid. Now I have milky-greyish solution and powder on the bottom. I processed only a fraction of whole batch to see if it works. Now I'm confused. I will follow the route and check what I will get. If yield will satisfy me, rest of the batch will also be processed this way.

 

[butcher]

Ander, the above suggestion was for the question you asked.
you would have needed to get those powder up to red hot to have driven off sulfides.

a better way to go from where you are now I think would be this.
can you filter the solution? and use stannous chloride to test this solution for any gold,testing solutions lets you know what is where.

Then take rinsed filtered material in filter, twist it wring it out, put it in stainless steel pan add a little rubbing alcohol and light it on fire, then adding heat with torch to burn, not melting the powder taking care not to blow away powder with torch, get these red hot and keep them at this heat and exposing them to air will oxidize them of coarse the gold if any will not get oxidized, but copper most all others will, let these cool, now you have no chlorides and can dissolve these powders in dilute nitric acid, let settle well and seperate any insoluble powders, these powders can then be dissolved in aqua regia and treated for gold or PGM. dont forget to denox your solution, evaporation I think is better than urea, this is where many people have trouble with aqua regia,
if you prefer HCl/ bleach could be used instead of aqua regia.
the nitric solution above can contain silver, lead and base metals. copper (this will cement silver as pepper which can be melted to silver metal) or you can use table salt or HCl will recover any silver as silver chloride, this silver chloride would need converted back to silver with NaOh and dextrose (or other method) before melting.

If I am not mistaken you are working with very small amount of material a few cpu's? with such a small amount you may wish to save these incenerated powders to treat with another batch later, as yields may be small?

 

[ander]

THANKS A LOT! Of course i filtered and rinsed the powder. Iadded then some isopropyl alcohol/acetone mixture to remove water with filtration for easier drying. Filtrate(filtered solution) is pale pink/yellowish, I saved it separately for further treatment. I process 6 CPUs. I heated the powder at lower temp. so I got some sulfides. I will follow your advice and use nitric acid. I hope it's going to work .

 

[Harold_V]

THANKS A LOT! Of course i filtered and rinsed the powder. Iadded then some isopropyl alcohol/acetone mixture to remove water with filtration for easier drying.

I question the wisdom of using alcohol anywhere in the gold or silver refining processes. With a bit of carelessness, it could prove deadly.

Harold