# 1st Attempt at AR on Ceramic CPUs



## cejohnsonsr (Mar 8, 2013)

I made my 1st attempt at the AR process on ceramic CPUs yesterday. I used what I learned from Sam & lazersteve's videos. I had 1 Pentium Pro, 1 AMD K5 & a handful of assorted old Pentiums. I broke them all up into small pieces. Not as fine as I would have liked, but much smaller than in Sam's video. Maybe about 1/2" or a little smaller. I put it in a 1000 ml beaker & added 200 ml water & 200 ml HCl. I Placed the beaker on my hotplate in a catchpan & allowed it to warm up. It was set to a very low heat (Dial is weird. Reads from min to 6. I set it on 2 to begin & increase heat gradually because I'm still just a little bit afraid of boiling acids.) There was a little bit of bubbling as soon as I put the beaker on the plate BEFORE I added any Nitric Acid. Not much. Just a few bubbles. After a few minutes I added the 1st Nitric. Only 6 or 7 drops from a long pipette. I got a little reaction that ended in just a few seconds but no red cloud. The 2nd time I added about 2 ml & got a pretty good reaction & a red cloud, but again, it ended in only a couple of minutes. 3rd addition of Nitric was about 3 ml. This time I got a very vigorous reaction & a red cloud that lasted quite a while. I continued the Nitric additions as needed using gradually smaller additions which took longer to finish. Total time of reactions was a little over 3.5 hours. Last addition was a few drops which produced no reaction so I added 100ml of HCl & waited about 5 more minutes before I removed the beaker from the heat. When it was cool I poured the solution into another vessel with some ice cubes. I noticed then that the solution was a VERY dark green. Almost black. After the white sediment (silver salts?) had settled I gravity filtered twice & allowed it to sit for several hours. After sitting I discovered even more white sediment in the bottom so I filtered again. I now have a 1000 ml measuring cup with a lot of white sediment in the bottom. Maybe 25 - 35 ml in 100 ml of rinse water. And a 1000 ml beaker with the VERY dark green (almost black) diluted AR solution. It's not yellow like it should be & like I expected. Stannous test is negative for gold. I'm really at a loss as to what went wrong. I read everything I could find about processing ceramic CPUs before I started. (1 thread is 17 pages long.) Everything proceeded as expected except for the color of the final solution & the negative stannous test. I can't help thinking I used too much Nitric Acid somehow. Even after all the reading & studying, if that's it, I'm still not quite sure how to get rid of it except to add some gold (which I can't do) or evaporate (which I can do). If evaporation is the answer, does that mean to just let it sit or should I put it back on a very low heat? Any help is appreciated.

Thank you,

Ed


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## cejohnsonsr (Mar 8, 2013)

My 1st miscalculation. I didn't have 400 ml equal parts water & HCl to begin with. I had equal parts water & HCl which, combined with the volume of the broken ceramic chips, equaled 400 ml. So I'm fairly certain I used too much Nitric Acid even though I added decreasing quantities until there was no more reaction. I also think I had the solution too hot & mistook boiling for reaction. 

I searched the forum a little more & found some posts on "denox". Specifically, evaporation. Thank you, again, butcher & Harold. I had to divide my solution again. My largest beaker is 1000 ml & after filtering & rinsing I have almost 800 ml of total volume. I put 4oo ml in a beaker & put that on a very low heat to begin evaporation. I don't know how long it will take, but I guess that's what I'm going to have to do. I'm also not certain about how this works. Hcl boils at about 176F(?). Water boils at 212F. Nitric Acid boils at 248F. I really wish I understood the mathematics of chemistry much better. 

Still welcoming any advice, help &/or edification,

Ed


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## Kevmau5 (Mar 8, 2013)

Although I've never done any refining myself, I'm sure I remember seeing posted on the forum that excess nitric acid will show negative for your stannous tests. So you may have too much nitric.


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## Barren Realms 007 (Mar 8, 2013)

My guess is that you processed the gold plated covers with the batch. If everything is off of your chip's there is a good chance your gold is in your filter paper.


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## Palladium (Mar 8, 2013)

It could be cemented in the copper tungsten heat spreaders.


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## cejohnsonsr (Mar 8, 2013)

Barrren Realms 007: I did process everything. I don't think anything is left in the filter paper. I washed it all down thoroughly when I rinsed off the white sediment. 

Palladium: If I did cement the gold into the spreader, what do I do now? I'm determined to learn this & NOT lose my gold. I've read a little about the tungsten, but not being a chemist, I apparently didn't get it. 

What I've done so far is to begin evaporating at a little below boiling. I can only see the color of the solution around the meniscus because the solution is so dark. It was green. After several hours on the heat & after reducing the volume by about 100 ml, the color is now a yellow brown. I don't know if that's a good sign or not. Beginning to rain here in Joplin & I can't stay with it all night so I turned the heat off. I'll continue in the morning.

Thanks for any help. I truly appreciate it.

Ed


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## Geo (Mar 9, 2013)

dont toss or discard any solids. look at the processors carefully. where the legs were. is the ceramic base flat with little round green dots or is the surface rough and bumpy? the copper tungsten heat spreader will soak up some gold but it shouldnt have removed all the gold from solution. take a 10ml sample of the solution and put it in a container and add 10ml hcl. this should lighten the color so you can do a proper test. use a spot plate or plastic spoon.place 1-2 drops of the lightened solution in the test vessel and add 1 drop of stannous. look closely as the drop of stannous comes in contact with the solution. what was the reaction. did it lighten or did it sort of darken and then lighten quickly? in either case, add a heavy piece of copper metal to the solution and allow it to sit for several days to reclaim any values in the solution. be sure to use a small brush to brush the copper off back into the solution when you pull it out.
take the left over material from the CPU's and add about a 100ml of hcl to it and add a couple of doses of chlorine bleach in 10ml increments. allow the solution to sit on the material for about a minute and decant into another vessel. dont worry about filtering yet. test this solution with stannous chloride. a positive means there still gold in the material.


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## cejohnsonsr (Mar 9, 2013)

Thank you Geo. I haven't thrown anything away. I'll do everything you suggested later today. I'll take careful notes & try to get some pics so I can answer your questions accurately. My hard drive died so if I'm a little slow answering that's why. I'm working on a borrowed laptop when it's available.

I should also mention that I had 5 old (early 90's) Apple/Mac CPUs in the batch too. As of this morning, the beaker that I've been evaporating is back on the heat. I tested with stannous again. The liquid is still very dark & green on a q-tip. Stannous turns a VERY light purple after a few seconds. It's hard to see because of the green, but I'm sure it's positive. The remainder of the liquid is in a 1000 ml measuring cup. The liquid in the measuring cup has cleared to a very pretty emerald green. On the q-tip it looks a little bit yellow green. Stannous turned almost blue but then changed to the same color as the liquid in the evaporating beaker. I can also see a little bit of some kind of "scum" floating on top of the emerald green liquid. It may be gold. I've seen some pics where gold floated this way. There is also some more sediment in the bottom of the measuring cup. I'll have to decant to see if it's the same white sediment as before. If so, there must have been a lot of it. I'm guessing it's silver chloride(?).


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## cejohnsonsr (Mar 9, 2013)

I did as you suggested, Geo. Since I had 2 containers I took 2 samples. You can see the stannous tests on the spoons. 2 drops turned almost blue. I could see the change as the green changed color. 2 more drops finished it. Both samples reacted exactly the same. The spoon on the right is from the beaker that I had been evaporating. The solution was a darker shade of green. About the same difference as the shades of blue seen in the pic.

I really hadn't looked at the leftover pieces until now. I was surprised at what I thought I saw. Some of the legs were still there but I didn't think there was any gold left. Stannous proved there was. Those pics are included also. After the stannous test I put the HCl Cl back on the material. I figured I might as well let it dissolve as much as it could.

I bought a solid copper split bolt (like the kind used for a big ground wire). I put it in a beaker & then added all of the solution.

I know I have to wait a few days for any values to drop from the solution. What do I do after that? Try to remove everything except the gold with Nitric? Then dissolve the gold & proceed as it was supposed to the 1st time?

Thanks for the help. I really appreciate it.

Ed


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## butcher (Mar 9, 2013)

It looks like most of the gold is still on the ceramic CPU's, there may also still be base metals like copper in them I do not know, much of your gold could have plated back onto the remaining copper, your stannous test does show some gold in solution but it does not look like much to me, most of your gold still looks like it is on the CPU's.

I am not sure what originally happened with your aqua regia, how much acids you used, if you used homemade nitric, or if they were very dilute, cold, or what, but you did not put all your gold into solution, did you use enough HCl for the amount of gold you had, and what strength? If you did not have enough HCl for the amount of metals you could have used up all of the HCl, if there was enough HCl did you stop nitric acid additions too early? If you had unreacted HCl and enough HNO3 it would dissolve the gold, if either of these acids are consumed the gold will not dissolve, although if acid solutions were very dilute it would take much longer, Heat is another factor, in a cold solutions acids are not as strong, the nitric may look consumed and seem to quit reacting (no visible reaction noticed), and if this same solution was heated the acid would still dissolve a lot of metals, dilution can also play a big part in the time it takes or how fast a metal may take to dissolve.

Acids with metals can the reactions be very vigorous at first, then slow down and look like nothing is happening, but they can still have a lot of action left in them, if heated or concentrated with the metal, sometimes it will surprise you how much more metal they will dissolve.

If your solution is slightly acidic you should be able to see fairly quickly if gold is going to cement out, but still let it sit overnight or longer, you should see it trying to plate to the copper, several factors like having the solution at least slightly acidic, if the solution is too concentrated it seem to slow the cementing process down, temperature play a big role here also, and since this is a contact reaction stirring solution is also important.

I do not expect much gold to cement out of the solution, but then again I can be surprised, the gold may be hard to see if not much of it, also a little may stick to the copper buss bar, even after your brush it off into solution, I normally do not worry about that little bit because I rinse and dry my copper buss bar and store it in a plastic bag, any gold on it I will get back later.

I do not know if anything I have had to say here will help or not.


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## Geo (Mar 10, 2013)

theres no need in using hcl/Cl on that material. start over with fresh acid using the same material. the gold is still with the CPU's. what is your source of nitric? is it nitric acid or sodium nitrate? finish the dissolution of the metal on the CPU's. in the future, ALL the metal on the CPU batch MUST be dissolved (not just the gold plating). be sure to heat the reaction below the boiling point of water. continue the dissolution until all the metal is dissolved and the ceramic bodies have little round green dots where the legs used to be.


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## cejohnsonsr (Mar 10, 2013)

Ok, it seems I need to start over. Let me start by answering some question.

butcher, I did the whole process with heat. I thought just enough to make it react, but now I think I may have had it too hot. I'm not certain exactly how much HCl, water & Nitric. I should have measured better & kept closer track of how many additions of Nitric.

Geo, it's supposed to be 67% Nitric Acid from ArtChemicals. I wasn't terribly happy with their service. I won't buy from them again & I don't recommend them to anyone else either.

*Now my questions:*

Can I use the 100 ml of HCl I used for the test by heating until the Cl is driven off, or should I start over with all fresh HCl?

I've seen a couple of recipes for AR. The first one uses equal parts water & HCl + Nitric Acid equal to 1/3 - 1/4 of the HCl added in small increments until there is no more reaction.The second doesn't use water. I used the first one. Is that the one I should have used?

*My Revised Plan For The 2nd Attempt:*

The starting material was 5 Apple/Mac CPUs weighing 131.64 gr, 1 Pentium Pro, 1 AMD K5 & several Pentium & AMD CPUs weighing 288.29 gr + 33.34 gr of CPU pins for a total weight of 453.27 gr. In a 1000 ml beaker the material was around 300 ml in volume. *I had originally expected to recover around 3 gr of gold.*

Assuming the 1st AR recipe is the correct one to use, I'll measure 200 ml of water & 200 ml of HCl. Now here's where it gets tricky. According to the General Reactions List provided by lazersteve:



> Hoke states 4 fluid ounces HCl + 1 fluid ounce HNO3 dissolves 1 troy ounce gold. This is equivalent to 3.8 mL HCl + .95 mL HNO3 per gram of gold.



So if I expect 3 gr of gold *AND* with the understanding that there are also base metals to be dissolved, 200 ml of HCl should be more than enough & Nitric Acid should be at least 3 ml but not more than 50 ml.

Is there anything glaringly wrong with this? Am I missing anything? I'm in no hurry so I'm going to wait for input/confirmation before I start again.

Thanks for helping me with this, guys. I promise it won't be wasted effort. 

Ed


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## cejohnsonsr (Mar 13, 2013)

I put a piece of copper in the failed AR solution for several days & got a little bit of black "sand" in the bottom of the beaker. It dissolves in HCl/Cl so I'm hoping it was gold. If it is, it's not much. Maybe 1/4 gr. After I removed the copper I hung a piece of shiny steel in the solution. I was amazed to see cementing for the 1st time. The shiny piece of steel looked like a piece of copper after only a few minutes. After an hour it looked like copper was "growing" on the steel. I have the original ceramic CPU material soaking in a 50/50 mix of HCl + H2O until I can try AR again. I combined all of the HCl/Cl from the tests & black "sand". Once the Cl evaporates I'll drop with SMB just to see what I get. 

Ed


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## cejohnsonsr (Mar 26, 2013)

The ceramic chips (pieces) have been sitting in a solution 50/50 solution of HCl/water since the last post. All of the legs have dissolved. Nothing left but the little green bumps Geo mentioned. I stirred it up & can see gold in the sediment in the bottom. I'm wondering if it will be ok to just heat this up & add Nitric to make AR again or should I drain off the solution & use fresh HCl/water? I don't have my computer (it died) so I'm working from memory & with what I can find here. My guess is that the current solution has dissolved most of the base metals & the gold remains in the material & that I should drain it & start over with fresh solution.

Ed


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## Geo (Mar 26, 2013)

the legs are Kovar (iron based). test it with stannous chloride. if the test is negative (be careful of a false positive), decant being careful not to pour out any solids and rinse with distilled water and start with fresh hcl. let all solids settle before decanting rinse or solution. remember to test every step you do.whether its a rinse or a chemical solution, test when moving liquids off of the solids. 

if the test is positive (which it shouldnt be with all that base metal), decant into a container and cement values on clean copper. rinse the solids and go from there.


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## cejohnsonsr (Mar 28, 2013)

Thank you, Geo. I thought that would be the proper thing to do. The solution these chips have been sitting in has turned green. I'm pretty sure copper will turn that color. Does iron/steel/kovar cause that as well? I'll be trying to cement again as soon as I can. I tried it on another batch of "spent" AuCl & got a surprise. Apparently my "copper" split bolt was alloyed with tin. At least that's what I think. I'm posting pics of the result on the thread, http://goldrefiningforum.com/phpBB3/viewforum.php?f=49.

Ed


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## cejohnsonsr (Apr 12, 2013)

Well I have managed to get everything else caught up & out of the way. Now I'm ready to try to finally finish this batch of ceramic CPUs. I sorted through the larger pieces of ceramic material & removed any that didn't have any gold left on them. Most were where the legs had been. Only green dots where they had been. Some of the pieces were where the dies had been. Nothing discarded. I just set them aside to make the rest easier to work with. What I now have is mostly a ceramic sludge with gold mixed in & some larger pieces of ceramic where the gold didn't completely come off. This material is in a 1000 ml beaker. I covered it with 200 ml of water to keep it wet. Total volume in the beaker is about 300 ml.

If I understand correctly, 3.8 ml HCl + 0.95 ml HNO3 will dissolve 1 g Au. I had originally expected to recover around 2.5 - 3 g Au. Since I didn't recover anything from the 1st attempt, I think I should still get that much. My question now has to do with the acid solution. In the videos I've watched (lazersteve & sam) the solution was 50/50 H2O + HCl with HNO3 added in small increments. Steve's General Reactions List, however doesn't include H2O in the formula for AR. So I'm wondering how to proceed. Should I:

Add 200 ml HCl, heat & then add HNO3 in small increments?

or

Add HCl + HNO3 to the current amount of water in the ratios above?

or

Remove as much water as I can & add the HCl + HNO3 in the ratios above?

I'm thinking I should probably go with the 3rd option. Just enough water to cover the material, then add 4 ml HCl + 1 ml HNO3 & heat. Wait until the AR has consumed as much Au as possible (about 1 gram). Then add another dose to consume another gram (hopefully). Then if there appears to be more gold left, add the HCl & only a drop or 2 of HNO3.

Hope someone can tell me if I'm on the right track here. The 1st attempt was such a failure that I want to make double sure what I'm doing before I proceed.

Thanks,

Ed


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## butcher (Apr 12, 2013)

Water is not needed, and the acids already contain water (which will usually need evaporated off at some point), if heating a solution sometimes water is helpful. 

HCl / NaClO bleach is much easier to deal with than aqua regia, either would work here.

If you do use aqua regia, I would not add water, add expected amount of HCl , if acid does not cover material a little excess HCl will not hurt (or you can add a little water to increase volume, warm the solution till vapors form, add your calculated nitric with a pipette in increments waiting between additions for reaction to cease, this will concentrate solution as you dissolve the gold, when all of the gold is dissolved finish concentrate the solution, add several drops of H2SO4 and finish concentration, if solution was yellow (copper not coloring the gold solution) you should see the gold chloride solution turning a darker orange color as solution gets concentrated, add just a little HCl to re-wet back towards yellow, evaporate back to orange, do this one more time, turn off heat let insoluble material settle, add a little sulfamic acid I add just a pinch of powder, decant solution to clean vessel add 3 time water to dilute cover and let sit so silver and lead precipitates, overnight, filter solution and precipitate your gold.

If using HCl/NaClO you will not need much heat, a good warm day is fine, dissolve gold , again adding you bleach sparingly, after gold dissolves, heat solution till vapors form, fill a cap full of ammonia hold it next to the vapors of your gold solution if you still have chlorine you will see a white cloud when vapor of ammonia and chloride forming a white smoke of ammonium chloride, when you do not see white smoke you have removed chlorine, dilute, let sit overnight for insoluble to settle, filter solution before precipitating gold,


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## cejohnsonsr (Apr 12, 2013)

Hi butcher. Here's what I did. I kind of split the difference with the water. I removed 100 ml of water & added 100 ml of HCl. I then warmed it up a little & added 1 ml of Nitric Acid. After about an hour & 2 or 3 stirs the reaction had slowed to almost nothing but I could still see gold in the material. I added another 0.5 ml Nitric Acid & continued for another hour, stirring 2 or 3 more times to make sure all the material was well exposed.

It was at this point that I had to go get my grandson from school. The reaction had almost completely stopped again. I turned the heat off & left the beaker covered & everything just as it was. My plan is to turn the heat back on in the morning & continue. 

Right now the solution is yellow with a hint of green. Really mostly yellow. There is a fine sediment covering all the ceramic material & I imagine there is still quite a bit of fine sediment from the original material in the bottom. Stannous test VERY positive.

After it heats back up I'll give it a stir to make sure all the Nitric Acid is used up. Then I'll add a few drops of Sulphuric Acid & stir it up again. *This is where I need to make sure of what I'm doing.* It's at this point that I begin concentrating the solution. Right? And I don't remove the ceramic material or decant yet. Right? I just boil it down until it starts turning orange, then add HCl & repeat 2 more times. Then decant while still hot & allow to cool over night while the silver/lead (if any) settles. Then I can filter & drop with SMB. Right?

*Edited to add this:*I don't have sulfamic acid. I don't think I've heard much about it so far. Can you tell me what it's for?

Thanks,

Ed


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## butcher (Apr 12, 2013)

Ed,
I actually have gotten to where I concentrate or do my first evaporation as I dissolve my gold, it is not necessary, but I find it helpful and a time saver.

But you need to understand some principles, volatile gases may be the first to leave solution, then water vapors off before acid, HNO3 will be next and then HCl, sulfuric is almost impossible to vapor off from solution, its boiling point and azeotrope is so high.
Heating can help to make the acids react better, water can be vaporized off with no problem, but when the acid solutions concentrates we do not want the solution so hot we are just vaporizing off our nitric before it has a chance to oxidize the gold, but heat can help it to react better, after water is vaporized off the HCl will react better with the gold, but also as the solution concentrates and azeotropes we will also loose HCl to fumes (so the goal is to get most of the gold reacted before the acid concentrates too much, this is normally not a problem as the HCl is about 68% water any way, and then as it reacts it can also form some water from the reaction, I try to use most of the nitric before the solution gets too concentrated, as the solution is concentrated further it can dissolve more gold without the additions of HNO3 or very little maybe just a drop or two at a time, so being close to a concentrated solution with either all of the gold dissolved or just a small amount left I can then concentrate it down further to finish my first evaporation, here I add the few drops of sulfuric acid (sulfamic acid could be added here as an alternative as it will form H2SO4 in the reaction and help to remove nitric acid, help with keeping from making salts if you make a mistake and evaporate too far, and it can also help to form lead sulfates later just like sulfuric acid does), we do not want to boil the solution just heat it so it vapors and concentrates, after concentrated the first time we add back a little HCl (remember this is 68% H2O and we do not want to dilute much as it will just need vaporized off), the HCl give more HCl acid to the gold (we have vaporized off, it can also acidify nitrate salts so we may see brown fumes of NOx gas from free nitric,again we will concentrate to drive off water then nitric and get the solution to a concentrated gold chloride, we will do this one more time to insure we vaporized off any free HNO3.

DO NOT BOIL it would result in gold solution leaving the vessel.

Sulfamic acid (I buy it at home depot store where they sell floor tile it is used to clean tile grout), sulfamic acid destroys the nitric acid from solution, the byproduct of that reaction is a little sulfuric acid is formed, which is actually helpful with what we are trying to achieve here.

There are other choices beside sulfamic acid to help remove nitric, like leaving a little undissolved gold, or adding a gold button during the evaporations to help use up HNO3. 

Actually we only need one method to use up or remove nitric acid:
Minimum amount HNO3 added.
Three evaporation method.
Leaving some undissolved gold.
Adding a gold button.
Sulfamic acid.
But I have found it much better for me if I use several of these methods simultaneously to insure I have no free nitric when I go to precipitate the gold.

Remember to use your stannous chloride tests, not only are the great at indicating gold in solution, but it is also helpful to see that oxidizers are removed where gold can be reduced back to metal when you go to precipitate the gold back out of solution.


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## cejohnsonsr (Apr 13, 2013)

Hi butcher. I think I'm finally starting to get he hang of this. After looking at your list at the bottom of your reply, I see that I did the 1st one right. I used minimal Nitric. Only 1.5 ml. I think I'm going to have to use sulphuric because that's what I have on hand & I really can't afford to go buy sulfamic. But that should be ok if I understand correctly. I'll just add 4 or 5 drops to the solution when it's evaporated down enough the 1st time. (That may not be right, but I'm printing your last response as a guide while I'm working.) Now my question is, should I go ahead & decant the solution & all the sediments before I begin evaporation or should I just leave all the original material in the beaker & decant after the 3 evaporations?

Ed

*Edited to add pics & further comments*

I hope you can see these pics ok. I took 1 of the beaker so you could see what I have. Another from the top. There is some scum floating on the surface. I'm not sure if it's copper or kovar (iron?) from the pins or maybe a little of both. There is a also a fine whitish sediment settled on the ceramic pieces. The Q Tip shows the results of the Stannous test. You can see very dark purple near the end of the stick part. The solution is now more green than yellow. The Stannous turned purple to black so quickly that I had to do the test twice & watch closely to see it. I'm hoping that's a good sign. I can also see just a little bit of undissolved gold on a piece of one of the wafers (the glass part from the center of the chip?) that is against the glass. The heat is turned back on. I'm using just a little more heat than yesterday to help it evaporate faster. *I will not allow it to boil.* Total volume in the beaker is 300 ml so I'm guessing I should evaporate down to about 150 or at least below 200. Then add just enough HCl to cover. Then repeat. Also, I'll add the sulphuric at the end of the 1st evaporation & stir before I add more HCl.

Ed


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## butcher (Apr 13, 2013)

Ed,
Looks like you are doing great, You are getting a handle on it, your stannous test is proving two things, that you have gold in solution, and that you are not over using your oxidizer (nitric acid), Keep up the good work.

From this if you do keep up the good work you will not need the sulfamic to remove free nitric acid, I would still use the H2SO4, to help with the evaporation and for getting lead out of solution later, you would probably not need all three of the evaporation's, but I would do it any way, as it will be good insurance.

It kind of depends on the material I am working on how I do the process, if I can I do the dissolving and the evaporation with the undissolved material left in the reaction vessel, this first concentration can many times dissolve more values into solution, (sometimes when working with large volumes of powders this is not practical), I will normally decant from solids after I have removed oxidizer, through evaporation when possible, then dilute and let settle, it really would not matter which way you done it.

lets look at how much water we have in solution to get a guess of how much we need to evaporate off, we will figure our added water plus (the 32% HCl added has 68% water), (the 70% HNO3 has 30 percent water) and some water forms from the reaction, this volume of water would need vaporized off before our solution concentrates to the point where we would then be vaporizing off free acid, free acid is acid that did not react with the metals to make salts of the metals dissolved in solution, we normally try to have a little free HCl left, but we want to react all of our nitric if possible.

If you have much free nitric acid when you concentrate, you have to be careful of a boil over, which could result in your gold boiling over onto the ground, if you do not use a catch basin, even though you are not boiling while you concentrate your solution, the boiling point of acids change with concentration, and as the acids get concentrate (lose of water) they will come to a point of azeotropic acid (the most concentrated the acid can be and the point of further evaporation the acid make fumes of this concentration on further evaporation, when nitric acid gets to this point there is a subtle change in solution (you will only notice it if you are watching very closely at the point of concentration, and know what you are looking for, as you concentrate you may see some normal bubbling going on as waster evaporates, but once nitric becomes azetropic and just seconds before a boil over occurs, you will see many small bubbles forming at the side of the beaker where liquid meets air, when you see these tiny bubbles form lower your heat but continue to let solution evaporate free HNO3, after a while the majority of the free azeotropic HNO3 leaves solution and you can then raise back up your heat to continue your concentration as normal (this only happens with the first evaporation and when there is a fair bit of free nitric in solution. that the nitric azeotropes and tries to boil out of the heated solution seemingly all at once.


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## cejohnsonsr (Apr 13, 2013)

Hi again, butcher. I posted an uupdate earlier, but I don't see it or the pic. After the 1st evaporation I added the sulphuric & a little while later (about 25 ml) it did start to bubble so I reduced the heat. Also some grey/black scum formed on the top. It almost skinned the whole surface & started to dry on top. When I gave it a swish & a stir it broke up. Looked almost like the ceramic materiel. Can that stuff digest a little bit? Anyway, it broke up & either sank or dissolved. It's gone now. But now there is some whitish/greyish scum on top. Almost looks like fractals or maybe salt? I don't know any other way to describe it. I'm working on the 3rd evaporation now. About 75 ml left to go. Then I'll decant through coffee filters. I'm guessing I should rinse the material with boiling hot water & check with stannous after maybe the 2nd rinse? Then I'll let it sit & settle until tomorrow. If it takes much water to rinse I'll evaporate a little off before I chill with a couple of ice cubes. After anything else (silver etc..) precipitates I'll filter again & drop with SMB.

Can't thank you enough for your help. I remember when I 1st started this batch I was pretty sure I had lost everything. I have a much better understanding of what has to be done now. And with gold prices so far down, maybe I'll be able to get my hands on enough good material to do a real batch or 2! 

Ed


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## butcher (Apr 13, 2013)

After you last evaporation and you turn off the heat I would add another splash Of HCl, let it sit covered, if you see something floating on top try a stir and let it settle if it will, after it cools and everything that is not dissolved settles then I would decant to another clean vessel, (no need to filter at this point), I use a suction tool and a small plastic pipette to transfer the liquid without disturbing the powders, after you remove this liquid give the remaining solids a dose of water and stir, let it settle again and decant this water into the vessel with your gold (we want 3 to 4 times as much water as we had gold solution, so add this volume to your gold solution, I let it sit overnight in the cold outdoors But you could chill it in a fridge if you wished, the silver and lead will precipitate overnight and the solution should loose that murky look and clear up, in the morning decant the solution from the white powders, filtering the solution into another clean vessel.

Do your stannous test, Bow your head, and pray for lots of gold, and precipitate your gold, smile and wonder at the brown powder which forms, let it sit (overnight if your patient enough), then decant the solution (testing it for values), grab your notes with Harold's gold wash procedure, do your hot washes, dry melt the gold, take a picture to show it to us, and then go out back and bury your gold in a spot in the ground you will not forget where it is for those hard times ahead.


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## cejohnsonsr (Apr 13, 2013)

Well I don't know what to think now. I did as I said I would. Got a lot of sickly green looking mud on the filter. Solution is the same color but clear. A little white powder settled almost immediately. But stannous test is now negative. I don't get it. I tested at every stage & got strong positives every time. Now nothing. I don't know what to do now. Put it all back together? I don't know. The mud was the only thing that got a stannous reaction but I wouldn't call it purple. I'm stumped. 

Ed


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## cejohnsonsr (Apr 14, 2013)

I think I know what went wrong & I'm pretty sure it happened in the very beginning & it's my own fault. That sickly looking pale greenish mud in the filter is tungsten. The original batch of CPUs I broke up included a Pentium Pro & an AMD K5. Between the 1st run through AR, in which I used way too much Nitric Acid, the intervening spent sitting in 50/50 H2O/HCl & this final attempt in AR, the tungsten in those 2 heat spreaders completely digested. (Is that the right term for when the metal becomes powder?) Anyway, I bet that's what happened. Palladium mentioned this right after the 1st failed attempt. So, given my skill level (or rather the lack thereof) I guess my only options are to either hang onto this filter until someday when I might be able to separate gold from tungsten or, since there's not really much gold here anyway, throw the whole thing away consider it a lesson learned the hard way.

Anyone have any final thoughts on this subject?


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## butcher (Apr 14, 2013)

Ed,
No need to panic, you still have your values; we just need to determine, where the gold is and what is going on.

I am unsure where you are, did you do all three evaporation's, did you evaporate them down far enough, before you decanted, did you then dilute and let everything settle overnight, before decanting again?

When you talk about having material in your filter it leads me to believe that you did it differently Than I do, I normally leave all insoluble material behind only decanting and filtering the clear liquid.

Can you fill me in on what you have done so far and maybe some more of the details, volumes, how far evaporated, colors...

There can be a couple of reasons your solution may not test for gold with the stannous chloride, you do not have gold in solution, or there is oxidizer remaining that will not let the gold reduce back to metal in the stannous test, another possibility your stannous chloride has oxidized and is no longer useful.

Reviewing a few things here, 
You are working with CPU's that have base metals involved if all of the base metals are not removed, or they are not completely dissolved, they can reduce the gold back out of solution onto the remaining metal, or out of solution as powders.

When you concentrate your solutions acids and metals can form salts of that metal and acid, nitric for example can form nitrate salts, these nitrate salts when added to acid can reform nitric acid, this is one reason we need several evaporations to remove the nitric from solution.

If we do not take the evaporations down far enough, where we would not still have water in solution, or stopping evaporation while we still have dilute nitric acid in solution, we will not remove all of the free nitric acid, unless we bring the remaining acid down to its azeotrope mixture, and keep the evaporation going until most of that nitric vapors off at 68% nitric in the vapors and continue until all of the free 68% nitric acid liquid has left solution as vapor, before we add HCl (32% acid & 68% H2O), or we add water and re-dilute the solution containing free nitric, we will not get all of the free nitric out of solution during the evaporation process.

OK lets try to determine what is going on, 

Lets take a small sample of solution, in a test tube of something we can evaporate the small volume down in, just working with a few milliliters in our test, (or we could just add a little sulfamic acid to a few drops in a spot plate and skip the evaporation process), we can evaporate this small volume much easier to see if nitric may be the cause, we can do the same three evaporation process again on this test solution, an electric hair dryer, a candle or small alcohol lamp can be used as a heat source for the test tube , or even a small coffee mug warmer electric hot plate and our ceramic spot plate can be used to do the evaporations and test in, we can use a pipette to add a drop to re-wet between evaporations, the idea here is to remove free nitric acid from a very small volume of our liquid and retest it with stannous chloride on a Q tip or with ferrous sulfate crystal in a spot plate.

We can test our stannous with our known gold solution to verify our stannous chloride is still working.

We can do a small test leach of the powders and remaining CPU, we can add these remains to our ceramic corning casserole dish, heat them on low heat till about dry add a few milliliters of HCl a few drops of NaClO (bleach), stir it up, just a little heat and then a few milliliters of water, and then test the leach with our stannous chloride on a Q tip.


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## FrugalRefiner (Apr 14, 2013)

cejohnsonsr said:


> Anyone have any final thoughts on this subject?


Now you begin to see the wisdom of those who say take your time, study, read Hoke's book until you understand what she teaches, do the acquaintance experiments, start out with some small, test batches.

Many people like to quote Edison who said he learned a thousand ways not to make a light bulb through his mistakes. I say that if I study what he did, I don't have to repeat those mistakes myself.

Dave


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## cejohnsonsr (Apr 15, 2013)

Hi butcher. Hope you won't take this the wrong way. I'm not giving up. I'll read what you wrote & respond when I'm able. But I'm not really able to continue for a little while. I'm a disabled veteran, in poor health, living on a fixed & very limited income. I had hoped that this might be a way to improve my means eventually. I had also hoped to at least be able to make enough to continue to learn. I put just about everything I had into this. Not that it was all that much. So far, after about 3 months I have 2.24 grams of impure gold powder & I've exhausted my resources. I really can't do anything else but read & study until I find some more $. One thing I can tell you is the stannous chloride is good. I just made it a few days ago. 1 gram tin powder & 30 ml HCl. 

I admit to being more than a little disappointed with my progress so far, but I'm not giving up. I just need to back off for a few days & take stock. I'll continue as soon as I'm able.

Thanks for all your help. I really have learned quite a bit.

Ed


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## butcher (Apr 15, 2013)

Ed,
I would not look at your situation at this point as a bad thing, sometimes when we get deep in a forest we may get lost in all of those trees, so many trees we cannot see our way out, if we tried harder to get out the more lost we can become, sometimes it may just be best to find a rock and just sit there a while enjoying the forest, then when we are not truing so hard to find the way out we see the sun and the trees shadow on the ground, then we realize when we came into this forest the sun was not in our eyes, it was warming our back along our hike into this forest, so when we are not struggling to find an answer the answer comes to us.

for me this is a hobby, not a way to make a living, with electronic scrap on a small scale, I do not see how you could make a living unless some one gave you tons of decent material.
I have told people who come here thinking the can make a living from electronic scrap that they could make better pay working at their McDonald's hamburger joint, this is not to say you cannot accumulate a little gold, some of these new members got mad at me for crushing their dreams of getting rich of of a few pounds of electronic trash, reminds me of miners with gold colored glasses giving up their good job, spending the last bit of their money on equipment to mine fools gold, and then taking it to a refiner and wondering why the refiner cheated them, and no matter how hard you try to tell them they are wasting their time mining that material they cannot or will not see it, they only see riches, they only see the trees in their forest and keep looking for a way out, but fail to sit quietly and see that ray of sunlight.

Backing off and sitting quietly for a while can be a good thing, you have a little experience under your belt now, and with more study, that ray of sunshine will shine on you, and when you are not, fighting to find the answer it will be revealed, as you know this forum and all of the information provided here can help with those answers, their are many ways a man could make use of what is learned here to help make his life better (refining electronic scrap may or may not be that answer).

Ed may the sunshine on you, and may you not be so busy looking for answer that you miss that answer.


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## cejohnsonsr (Apr 15, 2013)

Thanks butcher. I appreciate that. I never expected to get rich doing this. Maybe to make a little $ & have some fun & learn something new. Believe it or not, there was a time when I was working in IS/IT when I could have had several hundred pounds of old memory,ISA cards & Pentium Pro CPUs just for hauling them away. If I had known then what I know now.......... I still think it's possible to make a little $ doing this. I just have to be much better at doing it. Like this batch for instance. I forgot all about the tungsten heat spreaders until right at the very end. And, for the life of me, I don't know why I didn't let it cool & settle before I decanted. Couple of long days, a little bit tired & I out-smarted of myself. I'm going to do like you said & just take a break for a few days then look around & see what I can do. I really do wish I could find some good scrap & be able to buy it for a good price. Sooner or later the VA is going to pay me the pretty penny they owe me. Maybe then I'll be able to afford to buy all the right equipment & do all the experiments from Hoke. I'd like that. In the mean time, I'm broke. LOL! But I can read & study. I've even seen a few posts from folks who made the same mistakes as me. I can help a little & that's a good feeling too. I'll be back in a few days as time & computer access allows. (Mine is still busted.)

Thanks again,

Ed


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## steyr223 (May 2, 2013)

Evaperate it all the way down .is that where the color
Changes to orange because of concentration 
Add hcl to bring it back to yellow 3 times
Mine stays brown it never comes near orange

My material is still in the solution, i have taken
Nothing out almost 200 ic's that were quoted with
Confidence by lou to have .25-35oz /lb 

Does anyone have an explanation.

Sorry if i sound frustrated but it seems everyone 
Has a different way and just when i think i got it
I dont 
Ive tried holkes no change ,butcher no color change
Harold wait till bubbles mark the spot turn it down a notch
And when it bubbles again let cool add hcl and do it again
Still no purple 

Sam chimes in .i do what he say then never finishes
Im stuck on the middle waiting

I dont have an entitlememt attitude and you guys have always
Been great ,im definitely not upset with any members or the
Form, im just disappointed 

I guess i will chalk this one up as a loss and when the og
Comes back then i will learn from your ptompt answers
Till then 
I wish everyone riches of wealth and knowledge.


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## butcher (May 2, 2013)

steyr223 said:


> Evaporate it all the way down .is that where the color
> Changes to orange because of concentration
> Add HCl to bring it back to yellow 3 times
> Mine stays brown it never comes near orange



I am guessing you are talking about the evaporation process to get rid of free nitric acid here, gold chloride solution is a clear yellow solution, if it is concentrated its color looks orange or even a red orange.
If your solution is brown it is because other metals like copper are in the solution.

Steyr223, I am having a hard time trying to figure out what your question is, or what you are doing, or having trouble doing, I can see you are frustrated, but I am unsure of what.



> Sorry if I sound frustrated but it seems everyone
> Has a different way and just when I think I got it
> I don't
> I’ve tried Hoke's no change, Butcher no color change
> ...



This sounds like you are having trouble De-NOxing an aqua regia solution, and are not getting a positive test for gold, which you are expecting.

We would need a little better understanding of where you are, and what you have done up to this point, and a little better understanding of what your question or concern is before we can help.

Sorry I just do not understand what it is you are having trouble with, or why.
Don't get frustrated, there is an answer, or a solution to the problem, you will find that solution easier if you are not frustrated.


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## squarecoinman (May 2, 2013)

I think steyn is referring to this post 

http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=49&t=18197&p=183600#p183600

scm


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## steyr223 (May 2, 2013)

Sorry guys thank you
I found my gold 8) 

Im not sure. How to link but i posted here

http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=49&t=18197&p=183703#p183703


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