# Large batch gone bad! HELP!!



## greengold (Jul 9, 2010)

First let me say THANKS for this forum.Wish I had found and studied it long ago.I have spent the last several days reading and learning from so much of your combined knowledge and will continue to do so.My immediate problem is this: Thinking this was a moderate to simple set of procedures,reading the ebay -shor blogs,I collected my materials ,70% nitric,36% HCL,Urea,Sodium Metabasulfite (SMB),table salt,filters,5 gal buckets,large qty of sodium bisulfate(baking soda to nutralize any spills,set up outside in a covered but open area,set up several barriers of spill protection and took my best 7 lbs of plated computer scrap consisting of pins,broken ceramic processors,micon connectors,finger bds,etc,all trimmed but I know it still has lots of contaminants like solder,nickle,brass,copper,silver,etc.Ithought the 2 gal of nitric would disolve most that except for the gold and other PGM's not soluable in nitric.After about 2 hours,lots of red fuming,I had a deep ,clear green solution.I split that into 2 -5 gal buckets of about 1 gal ea.and then added 3.5 gal of hcl to each bucket to make the aqua regia.I let it cook over night,filtered out all the solids left from the chips,conn.,and fingers.Solution was still dark green and clear.I added salt thinking the silver would precipatate like cottage cheese.Nothing really happened.I then got the bright idea to throw in a couple of 2 lb copper heat sinks,remembering how I had read that copper would help to drop silver and gold if in solution.I did this with both buckets at the same time.Nothing much happened for about a minute,then both buckets violently boiled over with a brownish foam.They wouldn't stop,so i figured i had to get the copper out.I had my gloves,mask ,and apron on,so I grabbed the bucket and poured it out into another bucket,leaving the copper heat sinks behind.I lost 1 to 2 gal of solution and whatever was in the foam.I nutralized the spill with backing soda and washed the whole area down with lots of water.The heat sinks were 1/2 gone,figuring there was still lots of copper in solution,I slowly added some pieces of alum to hopefully drop the copper and whatever had attatched to it.They boiled away quickly.I filtered the solution in coffee filters.Had about 5 with some brown percipitant caught in them,but almost no percipitant in the bottom of the bucket.I added urea slowly,in dry form.It fizzed away after about 2 lbs was added.Solution was now brown.I slowly added the sodium metabasulfite which foamed yellowish with each addition.After about a pound and a half,the reaction stopped with the yellowish foam.I let it sit over night,thinking I would get my gold drop.The next day,still brown,no drop.I now had almost 2 full buckets of solution.I took half of one bucket to work on.I figured I had silver stopping the gold from being disolved in the AR,so i thought adding more nitric would solve that problem.I added about a quart,slowly.I started getting a reaction of a bright green slime/foam that didn't disapate.I spooned it off into another container,where about a gal of it still is.After the nitric produced no more green slime-foam,solution was back to green,i added more urea to kill the nitric.Solution turned back to brown.I heated part of the solution,about 3 quarts,to boiling,added SMB ,this time disolved in water.Still no drop after several hours.Tried putting ice in it,no help.I divided that whole mix into 4 seperate cups and added HCL to one,water to one,bleach to one and heated the last one.Tested each with a few bits of urea,to make sure the nitric was nutralized,added more SMB to each.Noticed the one with the extra HCL had a little black ,what looked like mossy mold rise to top.The one with the water seemed to stratify in layers,with the bottom being darker.The one with the bleach added,turned from dark brown to very light brown/green tea color,but no percipitate in bottom of cup.The heated one seem to statify ,going more dark towards bottom,and a little percipitate in bottom.I tested all the solutions with DMG,after the bright green foam appeared.All mixes showed purples and blacks,some more yellow and brown.After the division of the 4 cups,the HCL add cup showed very black as did the heated cup.The other 2 were just kinda greenish/brown.No purple showed after the 4 way division.
I now have many buckets and cups and containers of solutions,haven't thrown anything out,hopefully have not lost too much PGM's,have used up lots of acid and chemicals and still have nothing to show for it.After my readings today,i may try adding some iron to the 4 samples and try to pull out contaminants,but other than that,I don't know which way to turn.I do know now,I have done many things wrong,need much more education on these processes,I dont want to make my mistakes worse,but really need to deal with all these buckets of acid all over the place.I want to learn the correct processes since I have several hundred pounds of material to process.and don't want to send it off to a refiner as I have in the past. Thanks in advance for any tech help you can give me in dealing with this small crisis.


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## Barren Realms 007 (Jul 9, 2010)

Are we having fun yet?

Take each one of your batches and do them one at a time.

1. use a container about the size of a coffee cup. Fill about 1/4 full.
2. Add a couple of prills of urea, if you get no reaction put in a piece of copper plate and see if your gold will cement out.
3. If you get a reaction add urea in small amount till you have it neutralized and keep track of how much you add so you will know how much to add to the main container to neutralize. After it is neutralized add a slab of copper and see if your gold will drop.
4. One you get your gold to drop reprocess it. Corectley.

Find Hoke's book here for download and start reading.

You really need to seperate your diffrent items so your processing will not go wrong and you can control things.

And do test batches before you start something big, start small and work your way up.


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## shyknee (Jul 9, 2010)

> I let it cook over night,filtered out all the solids left from the chips,conn.,and fingers.Solution was still dark green and clear.I added salt thinking the silver would precipatate like cottage cheese.Nothing really happened


If there were any metallics that where filtered out ,then most of your values even silver would have cemented out on them .
So the filtered material should be tested for values first .
Then cement out all the liquids with copper and reprocess what cements out
And try to use baby steps (small batches at a time)
I wish I had caught the moment on film ( good luck ).
Any questions just ask.


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## g_axelsson (Jul 9, 2010)

greengold said:


> ... Thinking this was a moderate to simple set of procedures,reading the ebay -shor blogs,I collected my materials ,70% nitric,36% HCL,Urea,Sodium Metabasulfite (SMB),table salt,filters,5 gal buckets,large qty of sodium bisulfate(baking soda to nutralize any spills,set up outside in a covered but open area,set up several barriers of spill protection and took my best 7 lbs of plated computer scrap consisting of pins,broken ceramic processors,micon connectors,finger bds,etc,all trimmed but I know it still has lots of contaminants like solder,nickle,brass,copper,silver,etc.Ithought the 2 gal of nitric would disolve most that except for the gold and other PGM's not soluable in nitric.After about 2 hours,lots of red fuming,I had a deep ,clear green solution.I split that into 2 -5 gal buckets of about 1 gal ea.and then added 3.5 gal of hcl to each bucket to make the aqua regia.I let it cook over night,filtered out all the solids left from the chips,conn.,and fingers.Solution was still dark green and clear.I added salt thinking the silver would precipatate like cottage cheese.Nothing really happened. ...



Hello greengold and welcome to the forum!

I'm not going to comment on all what you wrote... you lost me after the heat sinks. :lol: But at least I can help you what you did at the beginning.

It's not that hard as long as you take it easy and not rush things along. Barren Realms advice is good for solving your crisis and return to a known starting point.

What you did was basically okay, except from mixing different kind of scrap. It's easier to control the refining and solve problems if you know what you are dealing with.
The first step was to dissolve any base metal with nitric, you got that right. At this stage all base metals, silver and some PGM:s are in solution. Now you should have separated the solids (gold, tin, plastics, ceramics and so on) from the liquid with dissolved base metals, either with filtering the solution or decanting it. The solids are then treated with aqua regia to get the gold and possible PGM:s into solution.
You just added HCl to the solution. HCl contains chlorides so any silver in solution from the first step dropped here as the cottage cheese you were looking for in the next step. Now you have AR that not only dropped any silver, it also dissolved all your gold so you mixed together the gold and base metals again, only now they are all in liquid form.
When you then filtered off all the solids any silver went with the solids. Your liquid is still full of base metals, you only removed plastics, ceramics, silver, tin and some lead. The liquid is also still full of acids as you apparently used way too much to dissolve the metals. So when you added the heat sinks the acid attacked the copper violently and it boiled over. The correct thing to do here would have been to neutralize the acid by evaporation (urea could be used to neutralize the nitric acid but not the HCl) and then cement the values onto copper.
You lost 1-2 gal out of 9 gal solution so you lost 10-20% of your gold in that step.  

As this was a large batch of mixed stuff and gold plated you should have a lot of nickel in it, that would give a purple color if you test with DMG. I've only used it as a test for nickel ores in the field, never as a indicator for gold. I suggest that the first thing you should do is to make some stannous chloride test solution so you can detect if you have gold in your different solutions. If the liquid is barren then there is no reason to continue processing it. Never run blindly when refining.

Btw, try to form your postings into paragraphs, it's easier to read and you will get more help. I almost skipped your posting as I just saw a large block of letters.

Good luck and let us know how it goes.

Regards, Göran


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## Anonymous (Jul 9, 2010)

greengold said:


> First let me say THANKS for this forum.Wish I had found and studied it long ago..



greengold: I see that you have managed to sign in to the forum, got your password figured out. 

Your in good hands now.

Snagged a newbie with my ebay auction, posted a link to the gold forum.

ttys
Gill


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## Palladium (Jul 9, 2010)

gustavus said:


> greengold said:
> 
> 
> > Snagged a newbie with my ebay auction, posted a link to the gold forum.



You been fishing again Gill ? lol


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## Noxx (Jul 11, 2010)

I wasn't able to read through your entire paragraph, sorry, so I don't know what the problem is. Maybe it's because it's 3 AM or something else...

My suggestions are:

-Put all of your solutions in a safe place, away from people and pets.
-Read Hoke's book.
-AR is not the way to go with mid-low grade plated material. Try to dissolve base metals first.


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## goldsilverpro (Jul 11, 2010)

greengold,

Welcome to the forum.

Please don't take this as an insult but, to me (and, so far, to at least 2 others), your post is very unreadable. I could understand it if I spent 1/2 hour wading through it, but I don't have the patience to do that and I would imagine that many others will feel the same way. It's obvious that you're a bright guy. Your spelling is excellent and, except for length, the sentence structure is fine. However, the paragraph structure is mainly what I can't cope with. Here's my suggestions as to making this more readable:

(1) I think that your post could have easily been broken down into at least 6 or 7 logical paragraphs, *with spacing* between each paragraph.

(2) It would really help if you left a space between the period and the first letter of the next sentence. In the same vein, spaces are needed between commas and the following word.

(3) Shorten some of your sentences. For example, the 4th sentence, starting with "My immediate problem," contains 103 words and just goes on and on - it could have been broken down to 4 or 5 sentences.

You're not this first to do this and you won't be the last. When I see one long paragraph like yours, where everything runs together and rambles on and on, I just refuse to read it and I know that many others won't read it. So far, except for Barrenrealms' suggestions, you have gotten little feedback. I guarantee that, if you are more considerate to the reader and try to make your posts more readable, you will get a lot more response. It is obvious that you spent a lot of time writing that, but I feel that this time was most probably spent in vain.

This forum isn't English 101. I am just trying to help you prevent wasting your time and am telling you how to best get meaningful answers to your questions. Here again, no offense.

Chris


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## Harold_V (Jul 12, 2010)

goldsilverpro said:


> This forum isn't English 101. I am just trying to help you prevent wasting your time and am telling you how to best get meaningful answers to your questions. Here again, no offense.
> 
> Chris


That was very well stated, Chris. I took a look at his post and moved on. I was in a hurry, not having much time at my disposal. I knew that it would bog me down and I'd never get to the things that were urgent here on the home front. 

Welcome to the forum, greengold! We're actually a pretty helpful bunch of guys, but it really helps if you can meet us half way with clear, concise messages. Make them easy to read and you'll get a great response. 

Harold


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## greengold (Jul 13, 2010)

Thanks for the input. My apologies on the big post with lack of paragraphs. I will keep it concise in the future. I don't know why I produced such a rambling, and in concise document other than feeling really desperate to get some of these processes to work. I do have a few questions.

1) I have a bunch of filters drying that have black,brown,bright green and yellow precipatants.How do I keep from combining contaminant metals that might make re refining these precipitants more difficult?

2) I have made a batch of stannous chloride for testing but remember reading it wont test solid particles of PGM's, only solution. Is there any way to test each dry filter and combine the proper ones for refining?

3) I used copper to cement out gold in my non dropping solutions. I ended up with a lot of black precipitate. Do I use nitric first on that, then add HCL to dissolve gold back out of recovered fines? 

4) Testing with stannous chloride, how do you tell the difference between silver, nickel, copper in black solution, and gold? I believe the gold will turn a dark brown to black. If it’s more black, how do you know what it is? The color reactions are not immediate but within 30-60 seconds


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## Barren Realms 007 (Jul 13, 2010)

greengold said:


> Thanks for the input. My apologies on the big post with lack of paragraphs. I will keep it concise in the future. I don't know why I produced such a rambling, and in concise document other than feeling really desperate to get some of these processes to work. I do have a few questions.
> 
> 1) I have a bunch of filters drying that have black,brown,bright green and yellow precipatants.How do I keep from combining contaminant metals that might make re refining these precipitants more difficult?
> 
> ...



1. Seperate you materials, with solder,without solder, copper base, iron/steel base. There is a lot more seperating if you get really into it. But those are the basics ofthe groups to digest.

2. Incinerate your filters and run the material again.

3. You should incinerate these materials as well or boil them in sodium hydroxide and then a run in nitric. Be sure and do your water washes between different solutions.


This link my help you some.
http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=6026


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## Harold_V (Jul 14, 2010)

greengold said:


> Thanks for the input. My apologies on the big post with lack of paragraphs. I will keep it concise in the future. I don't know why I produced such a rambling, and in concise document other than feeling really desperate to get some of these processes to work. I do have a few questions.
> 
> 1) I have a bunch of filters drying that have black,brown,bright green and yellow precipatants.How do I keep from combining contaminant metals that might make re refining these precipitants more difficult?


Don't worry about that at this point. You can safely look at the filters and their contents as substances that have been recovered, and are in need of refining. 



> 2) I have made a batch of stannous chloride for testing but remember reading it wont test solid particles of PGM's, only solution. Is there any way to test each dry filter and combine the proper ones for refining?


It's not worth the effort it takes unless each one has a significant amount of metal. Best to combine them in incineration. 



> 3) I used copper to cement out gold in my non dropping solutions. I ended up with a lot of black precipitate. Do I use nitric first on that, then add HCL to dissolve gold back out of recovered fines?


In this case, you might achieve success with a nitric digest---or you may wish to combine this material with the incinerated materials. They'll all receive the same treatment in the end, so it really makes little difference. If you need guidance in incinerating and processing this material, ask. Be certain you have an understanding of the processes involved, first, however. That will save you and us a lot of grief and trouble. 



> 4) Testing with stannous chloride, how do you tell the difference between silver, nickel, copper in black solution, and gold? I believe the gold will turn a dark brown to black. If it’s more black, how do you know what it is? The color reactions are not immediate but within 30-60 seconds


Stannous chloride will not test for any of the base metals. For them, you must become familiar with more testing procedures. Hoke discusses testing in her book, which is a wonderful source for gaining this knowledge. 
For now, you can test for copper with ammonium hydroxide (common ammonia). A drop of solution with a drop of ammonium added turns a vivid deep blue. If you suspect you may have nickel, a drop of DMG added to the drop of solution that has had a drop of ammonia added will yield a beautiful pink color. Silver can be tested with any chloride--even table salt. If you add a little HCl or table salt to a drop of the solution in question, if there's silver present, it will precipitate as silver chloride, which, in volume, is reminiscent of cottage cheese. If you suspect silver dissolved in wth base metals, you can also dip a piece of copper wire in the solution. If there's silver present, it will start cementing on the copper wire almost instantly, unless it's very sparse. Even then, you'll see silver form, although it may take a little time. Nothing else should plate out unless you have palladium in solution---which is hard to miss because of its dark brown color. It tests with stannous chloride, or with DMG. Read Hoke for a better understanding. 

Gold yields one thing that no other element does. It turns a dish purple. If you have highly concentrated gold in solution, the test may appear black, but it is very dark purple. That's one of the advantages of testing with a spot plate, which I encourage. After testing, the cavity will have a purple stain. Also, take note that if you have a very small amount of gold in solution, the color may not be vivid. It can also be influenced by a large amount of base metals. Best way to become familiar with these tests is to build some standard solutions, then, book in hand, go to your lab and conduct tests so you become familiar with the reactions. 

Mean time, and I'm dead serious---read Hoke. Everything you need to know to become a successful refiner can be found in her book, although she does not treat silver with much respect, nor does she address e scrap. There was no e scrap when the book was written. 

If you get slow reactions with your stannous chloride, it's possible that the stannous solution is weak, or it's even possible you have excess acid in your unknown solutions. If a test appears, then disappears, that's generally a sign of excessive free acid. When conditions are correct, these tests are instantaneous.

Harold


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## greengold (Jul 14, 2010)

Harold, thanks very much for the reply. You answered all my questions with great detail. I am finding the devil is definitely in the details and subtleties in these processes.

I will definitely be reading more of Hoke to better understand those details. It is great to know a Sensei is available to shed some light.Thanks again,Sensei !


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