Aqua Regia and Pulverized Ceramic IC Chips

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Dzimmy89

Member
Joined
Sep 2, 2016
Messages
10
Hello Everyone,

I have been reading Hokes book, and thought it may be easier to ask someone on the forum who has done something similar to what I am about to attempt. I have one kilo of IC chips and other various 4 sided and 2 sided chips. I was thinking of pulverizing them to powder, then exposing that powder to aqua regia and dissolving the precious metals as well as the rest of the metals that are in the solution. Then filtering the ceramic ashes, being left with the values in aqua regia solution. I can then use bismuth powder to precipitate the gold, and the perform another aqua regia bath to refine the gold once more. Do I have this completely wrong? Is there an easier way to go about this with IC and 4 sided chips?

Thanks for the help everyone!
 
Just to clarify, my goal is to refine the chips down to remove all of the metals, including the base metals, from the pulverized ashes of the chips. From there I can use another chemical wash to remove the gold and then purify it. This sounds reasonably, right? If not please let me know.

Thanks again.
 
Dont pulverize them. Fine powders are difficult to leech without agitation for the fresh acid to reach the metals. You can do it, but it isn't suggested.. It's hard to dissolve everything that way.. Then its difficult to rinse all the PM bearing solution as well...

It also is hard on your glassware. Ceramic processors are sharp, and have no troubles etching, scratching, marring, and scarring your beaker until it breaks. Also, hot metal powders sitting on the bottom of the vessel prevents even heat disbursement, so that too can cause a beaker break.

Why the choice for Bismuth? Copper is better... Its cheaper.. More readily available, and is generally the standard choice for PM cementation.

But, do indeed refine the powder a second time. Of course, after doing the proper wash procedure. You will be pleasantly surprised at the increase in purity/color if done correctly.

How will/would you precipitate the gold the second time though?

Have you downloaded Hoke's book (available free for download in the library and in member's signatures). Yes, it's old...but, the fundamental principles you will learn in her writing are still accepted practice to this day. I downloaded it, read it, then bought a copy for my library.. It's THAT good.
 
You didn't mention what kind of ICs these are. Ceramics are handled differently that resin. It's generally a better practice to try to eliminate as much base metal as possible before dissolving your gold. Dissolving everything at once complicates things and can cause you to lose values. The term "ceramic ashes" doesn't makes sense to me. I'm not familiar with using bismuth powder to precipitate gold. If you want to cement gold from a dirty solution, copper is probably a better choice.

Keep reading the book and reading the forum. I recommend a lot more study before you start dissolving your values, or you may create a mess and lose the precious metals you're trying to recover.

Dave

Wow! Some of you guys are quick and posted while I was still typing! :lol:
 
Thanks everyone for the fast replies!

So I want to clarify for everyone what I have, and what Im trying to do. I have ceramic IC chips, both 2 and 4 sided chips, not the plastic polymer chips, but the older ceramic chips. I have a bunch of pyrex chemistry glassware and a hot plate magnetic stirrer so that I can put a watch glass on top of the pyrex once all of the chips have been pulverized and added to the pyrex, then I can add the aqua regia solution, and heat it gently while stirring.
The goal here is to dissolve all the metals into solution, the use bismuth powder, although after reading the replies, possibly I should be using a different chemical to precipitate the gold from solution after filtering the solution through a glass funnel lined with cloth to filter out the ceramic while allowing the gold bearing solution to filter through.
I plan to save the ceramic and do a second wash using aqua regia in order to retrieve the greatest amount of values from the pulverized chips.

I noticed that one reply mentioned that It may be better to remove the base metals before exposing the pulverized chips to aqua regia, and I have seen that done before, I am just worried that I may lose some values in the process.

Also, If I don't use bismuth powder to precipitate the gold from the solution, what do you recommend I use instead?

Thanks everyone for your information and replies, It is truly appreciated!
 
Dzimmy89 said:
Also, If I don't use bismuth powder to precipitate the gold from the solution, what do you recommend I use instead?
Click to expand...
See the responses above from Topher and I.

Topher_osAUrus said:
Why the choice for Bismuth? Copper is better... Its cheaper.. More readily available, and is generally the standard choice for PM cementation.
Click to expand...
FugalRefiner said:
I'm not familiar with using bismuth powder to precipitate gold. If you want to cement gold from a dirty solution, copper is probably a better choice.
Click to expand...
Dave
 
Here is a good image of the chips for processing. This is only a portion of the chips.
Here is the procedure I had in mind for the chips:
1.) Pulverize the chips into powder/very small pieces
2.) Add pulverized chips to 5000ml pyrex glass container on a hot plate with magnetic stirring mechanism
3.) slowly add aqua regia solution to the pyrex with the pulverized ceramic chips until the chips are covered in AR solution
4.) allow the solution to be heated and stirred for a period of no less than 24 hours
5.) Filter the solution through a glass funnel with cloth filter into another 5000ml pyrex beaker
6.) add either bismuth powder or another chemical like SMB or something else, as mentioned in previous posts, to the AR solution to precipitate the gold
7.) repeat the procedure once more with the pulverized ceramic chips to remove the greatest amount of values possible
8.) after the process is complete and I am left with the gold precipitate, I can use AR solution to refine it further then smelt it down to a button afterwards.

What does everyone think of the procedure? Should I replace the bismuth powder with something else to precipitate the gold from the AR solution? I saw in the previous post that Copper(II) Chloride solution is better to precipitate the gold from the solution. Or do you think there are any other changes that should be made?

Thanks again all!
 

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For precipitating from dirty solutions, ferrous sulfate (copperas) is also a good option sometimes.. But, with those, go with copper. I say that, because you will most likely use too much nitric and that too, can cause precipitation problems (which cementing on copper kindof circumvents that problem..[kindof]**)

But, after seeing those chips you speak of.. I am inclined to think that Patnors thread is your best bet honestly...
Patnor's thread-
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=52&t=11827

This is another good thread by Tzoax where he goes and does a few different types as well, and how he did them.. Also has a couple other threads linked in that one (patnors being one of them)
Tzoax's thread-
http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?t=20662

Hope this helps

Edit to add:
**- i say "kindof" because if you use a LOT more nitric than needed, you will consume a lot of copper in the cementing process.. So, its a pseudo problem I suppose.
 
And it's not copper chloride that will precipitate the powder.

Its actual, copper, metal.

When gold dissolves into solution with baser metals present, if there is not enough oxidizer to finish dissolving all of the base metal AND the gold, the remaining base metals will actively reduce the gold chloride to elemental gold as they "swap" positions in solution.

Do please read those threads i linked, as well as Hokes book. You may have losses without more insight to the processes, as our answers only give you a small portion of whats required to successfully recover and refine your gold.

Knowledge is one of the refiners greatest tools.
 
You need to slow down and do some sorting of those chips.

You have BGA chips in there that are suppose to yield higher than quad flat packs. BGA chips have little solder balls on them. People consider flat packs as having leads legs or pins on 4 sides.

Crushing those and going straight to AR is going to create a monster that you wish you hadn't created.
Read Pats post about recovering gold from chips. Most BGA chips have copper base metal in them. Most chips have iron based leads. That is going to cause problems dissolving both in any acid at the same time not to mention the tin content.
 
Ok,

After reading all of the posts, it seems that the most important thing for this extraction to be successful is to separate the chips according to what they are, and not process them all at once. Also, it seems that there may be some extra steps necessary to remove some base metals before crushing/pulverizing the chips. Using copper instead of any other chemical or compound to precipitate the gold in AR is no problem, I am going to sort through the chips and take photos of them once sorted. BTW, how to I identify if a chip is ceramic or if it is Polymer? That would be helpful. Also, should I be focused on a particular type of chip, since one poster mentioned that most BGAs contain only copper. I'm going after the gold here, so which chip should type should I focus on?

Thanks Again All
 
Thanks for the info. Now something I obviously need to do before proceeding is sort the chips. How do I identify ceramic vs. Polymer. You were able to do it just by looking, so what should I be looking for to identify the chips? Thanks!
 
Dzimmy89 said:
Ok,

After reading all of the posts, it seems that the most important thing for this extraction to be successful is to separate the chips according to what they are, and not process them all at once. Also, it seems that there may be some extra steps necessary to remove some base metals before crushing/pulverizing the chips. Using copper instead of any other chemical or compound to precipitate the gold in AR is no problem, I am going to sort through the chips and take photos of them once sorted. BTW, how to I identify if a chip is ceramic or if it is Polymer? That would be helpful. Also, should I be focused on a particular type of chip, since one poster mentioned that most BGAs contain only copper. I'm going after the gold here, so which chip should type should I focus on?

Thanks Again All
Click to expand...
Dzimmy, you started this thread talking about pulverizing chips, dissolving everything, and precipitating the gold with bismuth powder. Some of our members have given you some good advice about problems in your process, but you don't seen to understand what they've said. When I asked whether your chips were ceramic or resin, you clarified that they "not the plastic polymer chips, but the older ceramic chips". Now you say "BTW, how to I identify if a chip is ceramic or if it is Polymer?"

You've only been here a few days, and it's easy to get overwhelmed with the information available here. There are many different processes for the many different types of eWaste material.

Sorting your material is a good first step. While you're sorting, keep reading Hoke's book and the forum. You'll learn that cementing gold with a metal is a way of recovering from a mess. There are much better ways to precipitate gold from a much less dirty solution than what you're talking about creating. There are many threads about processing the different types of ICs. Take some time and read them while you're sorting. The longer you study, the more it starts to make sense.

Dave
 
Dzimmy89 said:
Thanks for the info. Now something I obviously need to do before proceeding is sort the chips. How do I identify ceramic vs. Polymer. You were able to do it just by looking, so what should I be looking for to identify the chips? Thanks!
Click to expand...

99.9% of black chips on boards made since the 1980's are plastic, ceramic chips are usually dark grey or white in color and are heavier than their plastic counterparts. If you do a google image search for 'ceramic cpu', there are millions of pictures that show what ceramic chips look like.

It is 100% possible to process all your chips together, but generally a good idea to split them up since the processing of BGA chips can be simplified a bit by getting rid of the Tin first, where chips with legs I usually get rid of the Tin later in the process. Different chips also have vastly different yields, so when you separate them out, it's much easier to know whether you are getting the gold you expect.

Really, you need to go and read quite a bit more and watch every youtube video you can find on the subject, that way you will begin to grasp the reasons why things are done in a very specific order.
 
Thanks so much!
I will keep reading through the forums, and go from there. I have read so many different posts where people are asking for help after creating a mess, and my goal is to not only avoid creating a mess, but extract as many values as possible. So I will continue to read Hoke's book, and continue to read the forums.

One last question though, how do I identify the difference between a polymer chip and a ceramic chip? I feel like it should be pretty self explanatory but it doesn't hurt to ask.

Thanks!
 

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