SMD capacitors and resistors yield

[kjavanb123]

All,

Today we smelted 11kg (22lbs) of SMD capacitors and resistors, we collected a 178g alloy of silver and palladium from this, and once we dissolved the alloy in nitric acid, to my surprise there was 9.4g of gold.

This gold powder, was added to gold powder produced from 40lbs of mixed ICs, and got the following button of 38.9g of gold.



Here is a sample of nitrate solution, it test positive for Pd, so I added salt to it to precipitate silver as silver chloride, filter and rinse well, and drop the palladium with zinc powder. Here are some photos for your reference.

This is the nitrate solution after the silver alloy result of smelting SMDs.


This is the same solution after adding NaCl, believe this precipitate Ag as AgCl.


Herre is a shot of silvr chloride, and deep orange solution which tested positive for Pd.


Filtering AgCl to cement Pd later from the orange solution.


This was a sample drawn from the main bucket that holds a gallon of Ag Pd nitrate solution. I will continue this as I will report the yield I got here.

Best regards
Kj

 

[patnor1011]

Did you managed to get picture of starting material? How that capacitors and resistors mix looked. It seems to me that you obtained very little from 11 kg you got only tad more than 1% of concentrated values. It all depend on starting material but I would expect at least about 500g - up to 1100g according to what other people got from that kind of material.

 

[solar_plasma]

I wonder where the gold comes from. On one out of one hundred PCBs I see maybe one or two mlcc shaped components with gold contact, so this cannot be the source. Some components may have been soldered to gold plated parts of the board, this would make sense, if the feed stock contained a lot of cell phone boards.

My last guess would be that the very small black three legged smd transitors have found their way into this batch and added up to this amout of gold? Or are you sure it was only mlccs and smd resistors?

About 1g per kg(!), - maybe all three possibilities have added up.

 

[Anonymous]

I agree with Pat and Bjorn.

I would love to see a picture of the starting material please Kevin could you do that please?

Jon

 

[Smack]

Not sure why this post is separate from the other post Can someone competent please merge his two latest posts?

 

[Smack]

Never mind, I guess the gold button would be the only thing relevant to the other post.

 

[kjavanb123]

Hi,

I was busy with this SMD refining. I took a close up shot with my iphone, it is a little blurry. This is the SMD mix that got that much gold.


Added salt (NaCl) to the burgendy nitrate solution of silver and palladium, filter the silver chloride.


Here is a sample of silvr chloride cemented with zinc. Cleaned with dilute hydrochloric acid.


Here is the Pd nitrate solution after silver cemented using regular salt. The main solution looks like deep red wine. Does that mean concentrated Pd solution or high Pd content? Well tommorow we will find out when I converted all silver chloride to silver metal.


For palladium nitrate solution, I am going to use zinc to drop palladium as black powder, clean it up with hcl washes, then dissolve it in as little nitric as possible to make it concentrated solution. Then I have to go back and review my old post about how I did refine palladium nitrate from cataltyic converter project.

Sodium chloratd granules added to hot concentrated palladium nitrate solution to preciptate palladium salt as red powder, rinse with 15% ammonium chloride, dissolve the red powder in ammonia, filter, add hcl to ammonia palladium solution to precipitate canary yellow palladium compound, incinerate, pallet it, and melt.

Patnor,
Yes that is what I was expecting for ailver from this SMD mix. The smelter believes they are in slag and will be recovered in future slag melting day.

More data tommorow.

Regards
Kj

 

[patnor1011]

From what I see it appears that mix is quite full of plated pins and pretty much everything from boards. That can explain some gold and low silver content.

 

[solar_plasma]

Looking at that wild mix I would guess you got almost all gold, silver and palladium that was possible to get at all. Gratulations! It seems you finally succeeded finding the method that works best for you.

 

[MarcoP]

You didn't mentioned any metal used as collector, and that's also why the bottom weights only 178gr. I suppose you fluxed only but what mix did you used. I'm asking because I have very similar feedstock and I'm slowly understanding how painless could be smelting as a recovery method.

 

[solar_plasma]

Marco, there is a lot of tin. Somewhere has been written, that the tin that comes with the smd's would be collector enough.

Further, look at the pic, how much other scrap there is! I am excited, that he did get that much Pd at all! No, everyone, let's leave the church be in the village, this has been a great success!

 

[kjavanb123]

All,

Thanks for your kind words. Since I was expecting 500g or more of silver from this mix, we did not add any silver to the melt. I added 600g of cyrolite, and the smelter added 1 volume part borax, and 1 volume part soda ash. I will process silver chloride today, melt and use silver cell to get the pure silver, and also precipitate palladium as black powder.

Best regards
Kj

 

[patnor1011]

You cant really expect more silver from that mix. There may be 1-2% of silver in solder on some new boards, some will have just lead in solder. There is not many monolithic capacitors and small resistors which do contain silver in your sample picture (weight/mass ratio) and another thing is that they tend to weight less than other material in a mix - that is why silver result is smaller than expected in my opinion. Anyway it is a fast way to recover what is in there and it starting to resembling process what big players are actually using.

 

[kurtak]

Awesome Kevin

Looks like all your trial & error work is finally paying off 8)

Kurt

 

[kjavanb123]

Kurtak,

Thanks for your support. Steve from MBMMLLC is sending me 30lbs of motherboards he ran on their ewaste recycling system, so I can give it to this guy who will try to get copper using electrowinning, and the Ag, Pd, Au and Ta using smelting.

Today, I cemented black powder Palladium using zinc, cleaned it using dilute sulfuric acid, and ready to get sodium chlorate granules, then dissolve in minimal amount of nitric, get the Pd nitrate solution to near boiling, add the sodium chlorate, till Pd salts precipitate.

Here is the picture of black powder,


And this as it gets cemented,


More photos coming soon.

Regards
Kj

 

[kjavanb123]

All,

I finally recovered and tried to refine the palladium produced in this post. First, I poured 1/3 of black powder, into this 2-liter beaker, and added 250ml hydrochloric acid, 75ml hydrogen peroxide (35%). Stirred until all black powder dissolved into burgendy color.

Prepared a DMG solution, by adding 4g of NaOH, to 100ml of water, then added 5.8g of DMG. Stirred until completely dissolved. This DMG solution looks yellow.

Drew 100ml of Pd chloride solution, added 50ml of DMG solution, instantly thick precipitaion occured. Since the amount of Pd was unknown to me I added another 50ml of DMG solution, and the Pd solution turned greenish in color, so I added water and stirred and same canary yellow precipitated.

Filtered the canary yellow solids, to use formic acid and ammonia to turn it to Pd metal.

Here are some photos, please advise why the greenish color which turned yellowish by addition of water. Also, in the main Pd solution I noticed a gray and brownish residue that did not dissolve in hcl-h2o2. Filtered, rinsed multiple times, added some nitric and it dissolved the flufy brownish residue, but fine grays did nit dissolve in nitric. Please advise.

Here are the photos for better understanding,

This is 100ml of unknown amount of Pd solution, to the right is the DMG solution,


This is Pd solution after adding 50ml of DMG solution,


The same Pd solution few mintues, a black color layer stayed on top of yellow precipitant,


I added the remaining 50ml of DMG solution to the Pd solution, this time solution turned greenish in color which turned back to canary yellow by adding some water,


Filtered this thick canary yellow particles, and washed with water, to be boiled and mix it with boiling formic acid and ammonia per Hokes instruction to convert this yellow salt to black Pd metal,


More photos in next post.

 

[kjavanb123]

Here is main Pd chloride solution, filtering.


This is the residue not dissolving in hcl and h2o2 mix.


I added nitric to the above residue, instanstly, the fluffy residue dissolved tested possitive for Pd, but the following fine gray undissolved in nitric, I even tried zinc cementation with weak sulfuric acid, assuming this gray might be silver chloride, but nothing happened.


And finally the yellow Pd salt after few hot water rinses, ready to be converted to Pd metal hopefully tommorow. I think I am going to stick with the sodium cholrate method to precipitate Pd, then purify it with ammonia, add hcl and get the yellow salt. Then use DMG to get any traces that usually stay in the solution after using sodium chlorate.



Best regards
Kj

 

[kjavanb123]

Tried adding potassium chlorate to concentrated Pd chloride solution and just fizzing and no preciptation. So I added 8.7g of NaOH to 250ml of tab water. To that added 12.5g of DMG and poured it to beaker containing 250ml of Pd chlorate which Potassium chlorate failed to precipitate Pd.

Added twice the volume water, and pulp turned yellow. Filtering was a pain, but with 4 filters at it it was finished. Now I am drying the canary yellow salt.

I also made 19g NaOH, 500ml water and 28.4g DMG, added that to 800ml of concentrated Pd solution. Again had to dilute it with more water, and filtered the yellow powder.

Hoke says in case sodium chlorate not avaialble, potassium chlorate can be used, but after adding 50g of it to boiling Pd solution onlu fizzing and foaming occured. I dissolved black powder in hcl and peroxide.

Here is the picture of 250ml Pd solution next to it prepared DMG solution.


And this is after DMG addition to Pd solution and diluted with water.


Hopefully I will convert the yellow salt to Pd metal using formic acid method.

Regards
Kj

 

[kjavanb123]

Today I completed filtering the volumtious yellow powder, and dried them, then calcined them. So far there was 82g of Pd sponge, there is another batch that is being dried as of now, which I am hoping to be another 20g and that would make it to be 100g of Pd from almost 13kg of mixed SMD capacitors and resistors.

I will melt the powder on Saturday and will post the result and picture of the Pd button. Here are some photos of the Pd refining process.

Steam heating the wet orange powder,


Calcining the Pd salt,


Calcining completed over the part of powder on top of burner,


Notice the white smoke coming out,


Calcine completed, there was some yellow powder to be washed with hcl and saved in stock.


Again I can not express how greatful I am to be part of such amazing group of skilled people who have taught me everything.

Regards
Kj

 

[kjavanb123]

I repurified the palladium sponge, here is some photos. The original sponge weighed 87g. I dissolved it in hcl and hydrogen peroxide (35%). Heat it, then added 31g of ammonium chloride, then boil it, added potassium chlorate powder until the red powders formed.



A closer look at the chemical reaction, as the red powders travel from the bottom of the beaker to surface and came back down.


Here is the red powder being filtered. I used a 20% ammonium chloride solution to rinse them in the filter.


The filtered solution tested strong Pd in the solution, so I will have to repeat this addition.

Regards
Kj