# NEC telecomm box components



## kjavanb123 (Jun 4, 2019)

Hi everyone

Hope all is well. The same seller who brought had brought me vitnage sparks plug, gave a few components he had removed from a telecomm box he had purchased as scraps.

He had already done similar contacts using lead smelting but wanted to do them cheaper using chemicals.

The following are 4 different samples which he gave me and wanted me to process each sample separately and report its yields.

So please kindly post their correct techniccal names if you know them.

Sample 1
I divided it into two sub samples, one long stainless steel looking one and brass looking pieces.

There were total of 6 brass looking samples and and many more of stainless steel looking (as it turned out, it only looked like stainless steel, wheb it dissolved in nitric acid the color was copper based alloy, maybe bronze)




Upon close inspection under a lope, there were two tiny contacts which supplier claimed to be Pd, at one side of the sample 1. Here is a closer look,



Here is the bronze / brass color sample, 



Here is a closer look at the contacts on one side of the tips, according to the supplier, these two sub samples were connected together.



More in the next post.


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## kjavanb123 (Jun 4, 2019)

Here are photos of the other samples, which shared similar contact points as the the first sample.

Except the sample 4, which according to visual inspection, supplier claims and test showed gold, palladium and possibly one other PGMs.

Sample 2



Sample 3
The line which contacts were attached to the end of it on this sample was a lot shorter than other ones



Sample 4



More next post


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## kjavanb123 (Jun 4, 2019)

Supplier had asked me to test the sample 4 as he claimed it has gold in the contact.

So here is the sample 4 broken down into its parts.



Here is a close up of the 8 pins at the bottom of the above picture, under a closer look you can see some of the contacts have a yellow tint.



I used scissor to remove the part of pins thaf contacts were attached to.

Total cut parts weighed 1.60 grams. Dissolved them in dilute nitric acid, as you can see solution turned green and reaction with nitric was pretty fast, so the based must have been an alloy of copper.



Here is what was undissolved in nitric acid, here is some pieces of gold foil and some gray color foils which can either be aluminum or Ir or Pt.



Next post I processed the palladium nitrate solution from processing sample 4 contacts


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## kjavanb123 (Jun 4, 2019)

Here is the green solution after adding 5.85 g of DMG dissolved in 4 grams of NaOH which had already mixed in 100 ml distilled hot water.



Upon filtering and washing the color of participant didnt change, so I cemented it with zinc powder and HCL, here is the final undissolved palladium black from sample 4 contacts.



It is being dried, as I had weighed the filter paper and it weighed 1.01 grams. Once it is dried weighed I will know how much Pd from that one sample 4.

Amount of gold and unknown foil is so small that I am not able to weigh.

More results in 10 hrs

Thanks and best regards
KJ


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## glorycloud (Jun 4, 2019)

Nice post!!


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## johnny309 (Jun 4, 2019)

So ...I read wrong,or maybe not....from 0.16 grams of contacts ..you have 1.01 grams of powder?
That's magic.
That seems to me like an average relay contact point of relays used in 70' in telecom industry.
If you can provide an type of it ...serial....can be identified.
by the look of your picture and your solution is Pd/Ag ...30/70 alloy...speed in HNO3 diggestion and the green colour.....and Au flash...5um in thikness....but tear down by age....
If you drop with Zn.....Cu will drop too....this is why you have that much powder.

P.S.: why ...NaOH involved in this?.......Why do you have to raise the Ph ....nitric is allready spent dissolving metals and forming salts...


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## g_axelsson (Jun 4, 2019)

johnny309 said:


> P.S.: why ...NaOH involved in this?.......Why do you have to raise the Ph ....nitric is allready spent dissolving metals and forming salts...


DMG is weakly soluble in water unless the pH is high, read Freechemists post about it at:
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=9477
So the NaOH is used for dissolving the DMG and that solution is then used to drop the metal.

http://goldrefiningwiki.com/mediawiki/index.php/Dimethylglyoxime

Göran


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## kjavanb123 (Jun 5, 2019)

johnny309 said:


> So ...I read wrong,or maybe not....from 0.16 grams of contacts ..you have 1.01 grams of powder?
> That's magic.
> That seems to me like an average relay contact point of relays used in 70' in telecom industry.
> If you can provide an type of it ...serial....can be identified.
> ...



Hi

I do not have that information about make and model of the telecomm main box.

Actually I made mistake it was 1.60 grams and changed that here. My scale can show 0,01 g and up.


I dropped Pd using DMG, and according to members with more experiene, that NaOH in the DMG mix, precipitates other metals but since more acid is there they get back to to solution and only Pd salt remains.

In sample 1 no silver was found.


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## johnny309 (Jun 5, 2019)

Thank's
Göran

The idea was that he follow the exact numbers from Wikipedia...aka 100 ml of water,5.81 grams of DMG and 4 grams of NaOH....and his beaker has under 50 ml of solution.
This is an standard test solution....methods for dropping PGM from solutions are others...less expensive.
When he failed....he put Zn in the solution....create more mess....and get back to the square 1....meanwhile loosing time and consuming DMG....and finaly...not a clear result of the metal alloy from those contacts.
I agree that GRF is loaded with information and helped many people....
This why I have to point it out that he is doing it wrong.


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## kjavanb123 (Jun 5, 2019)

Could you please point out what is wrong with my procedure?

I have used the same DMG formula before, freechemists also provided very similar if I correct his was using 2.5g of DMG per 100ml of 4g of lye.

Zinc cementing the DMG Pd salt is also a method of choice for converting Pd yellow to Pd metal, and it causes a lot less losses than calcining.

I am drying and weighing the final Pd powder from processing samples 1, and 2-3 and will post them here.

Best
KJ


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## johnny309 (Jun 5, 2019)

Drop with Zn?
Not providing free Cl- ions to an metal to form an ZnCl2 mix...the Zn will drop like an black powder.
So.....is this black powder PGM?

Put the black powder in an beaker and add HCl...and cover it...if is Zn...will release H2....and in a fast way.


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## kjavanb123 (Jun 6, 2019)

Not drop with Zn, cement with Zinc


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## kjavanb123 (Jun 6, 2019)

Finally after drying and weighing the powder, rrcovered from contacts of sample 1 stainless steel looking and brass looking pins,

Total of 0.460 grams of Pd powder was recovered.

Sample 2 and 3 are being dried.


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## kjavanb123 (Jun 7, 2019)

Hi

Total Pd powder recovered from sample 2 and 3 contacts, which were cut manually, weighed 0.4 grams.

Total weight of sample 2 and 3 cut contact points were 1.17 grams.

There were 0.18 grams silver chloride, and 0.07 grams of meta stannic acid also produced from these two samples.

Best regards
KJ


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## kjavanb123 (Jun 7, 2019)

Supplier had also gave me a piece of wire for testing, here is a photo of that.



A cm of that was cut and first tried to dissolve it in hot dilute nitric acid, it didnt react.

Again tried to dissolve in HCL and no effect,

I made aqua regia then after 10 minutes of heating brown fumes appeared and solution turned to this color.



There were some foils undissolved and can be seen at the bottom of beaker. 

I tested the wire with magnet and it was pulling it not strongly though, but it was magnetic, so conclusion it seems like Ni-Cr wire.

Just to be sure filtered the solution, and added DMG and this red particlpiant settled which is indicative of Ni.



Next phase will be melting all these Pd black in an electric oven.

Here is the Pd cemented from processing samle 1 stainless steel looking pins, under the phone light it is dark gray color but in regular lighy looks black.



Hope these help someone if they find a similar scrap.


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## kjavanb123 (Jun 10, 2019)

Hi

I sent all the filter papers with black Pd powder in them to this trusted jewlery shop which have melted a lot for me in the past.

He called to let me know there was absolutely no beads after melting 0.9 g of black powder.

His procedure was damping the filter papers then adding borax and slowly melting using oxygen-buthane torch.

Last time this happened to me it was due to faulty zinc powder that was used in cementing the yellow Pd powder.

I am going to collect the dish he melted the powder in tommorow to see if I can dissolve it in nitric.

Best regards
KJ


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## anachronism (Jun 10, 2019)

You say your supplier says there might be Pd- what has he based that upon? Has he seen Telecoms points and made the assumption that "there must be Palladium" or has he actually had tests done that he can show you? 

Not all Telecoms points have any PGMs. Silver, and/or gold plated material was used for the majority.

Jon


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## kjavanb123 (Jun 10, 2019)

He said that based on his previous experience dealing with the same materials.

I also have used DMG to drop the Pd from solution.


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## anachronism (Jun 10, 2019)

I read that you have a black powder that someone has tried to melt but cannot get a bead. I've also seen a pic of some precipitate from DMG which you say is green, but looks pink to me. Maybe it's the light?

Either way what's conclusive about Pd here because it looks (so far) more of a matter of hope rather than evidence? I'm more than happy to be wrong but everything so far appears to be supposition and hearsay wouldn't you agree?

I'm not sure there's a great deal wrong with your process Kevin, but I think the fault lies in being told there is Pd, and then assuming that there must be Pd there without conclusive results. In my limited experience of DMG, it's hyper sensitive to the presence of Pd and is extremely visible in its presence if tested properly in a dilute solution and given time to precipitate fully. You appear (at this moment in time) to have evidence of Nickel. 

Thoughts?

Jon


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## kjavanb123 (Jun 11, 2019)

Hi Jon

Thanks for your comments. Here are the DMG salt prcipitated after adding DMG solution to nitrate solution.

For sample 1 stainless steel looking pins



For sample 1 brass looking pins



Unless DMG can drop any other metals ezcept Ni and Pd, the color of DMG salt there was close to canary yellow.

I am going to test a small Pd black that is left and dissolve it in nitric and check with stannous to make sure these black powder indeed are Pd

Thanks and regards
Kj


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## anachronism (Jun 11, 2019)

Hi Kevin

Thanks for the second pic. As you say that certainly looks a lot more Pd like than the first pics. 8) 8) 

Jon


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## kjavanb123 (Jun 11, 2019)

Hi

I had some black powder cemented out using zinc from DMG salt from scrap that was positive for Pd, 

And dissolved that powder in nitric acid, expecting to see a brown solution but it was green like the solution above.

So from solution to DMG salt seems ok, when cementing DMG yellow with zinc it produce a metal that is not soluable in hcl yet black / dark gray in apperance.

I suspect there is something wrong with zinc powder I use for cementing, maybe too much cab o sil?

Keep u all posted


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## johnny309 (Jun 12, 2019)

If you suspect that your zinc powder is not pure Zn....dissolve some powder in HCl.....if is pure...H2 and ZnCl2(colorless solution) should occur ....no sediments...


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## kjavanb123 (Jun 15, 2019)

Hi

Actually I bought a new zinc powder and it worked just fine.


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## kjavanb123 (Jun 20, 2019)

Hi everyone

Supplier of those samples clipped the contacts from the entire telecomm box and sent then to process for Pd, Ag, Au and Pt

Here is the first type of contacts which weighs 22.17 grams



Dissolved them in warm dilute nitric acid



Added couple of drops of hcl till no more white appeared, let it settle as silver chloride



Checked the green solution for Pd, stannous chloride testing solution turned dark brown, indicating a concentrated Palladium solution.



More in next post


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## kjavanb123 (Jun 20, 2019)

Silver chloride was filtered and washed throughly with hot water till the solution passed the filtee turn clear and stannous test showed no more Pd.

Silver metal from cementing with zinc powder and hcl.



That silver metal powder was washed till passing solution showed ph 7 on the pH meter.

The dried silver powder from 22.17 gram lot 1 weighs 1.39 grams.


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## kjavanb123 (Jun 20, 2019)

After nitric acid dissolved the contacts of lot 1, there was some white powder which it is believed to be tin,

And some heavy black fine powder as can be seen here



Washed them to a beaker added hcl and put it on steam bath, added few ml of hydrogen proxdie (35%) and after 10 minutes got this solution



Based on the color of solution I gussed it to be gold, but further testing with stannous chloride testing solution indicated Platinum



Since there was no Potassium Ammonia salt available to precipitate Pt, I used zinc powder



After washing and drying that powder it weighs 0.06 gram of Platinum powder.

Next post Palladium


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## kjavanb123 (Jun 20, 2019)

Ok the dark green solution that had shown concentrated Pd, after removing silver and adding the silver chloride washes to it

I checked the pH of that and it shown close to 3 so I added 200 ml of nitric acid to that solution and stirred.

Prepared a DMG solution, added 4 grams of lye to 100 ml of hot distilled water, to that added 5.81 grams of DMG.

Let it cool, and added it to 600 ml of dark green solution and this appeared



After filtering the yellow Pd DMG salt, checked the solution and still showed Pd presence.



Again prepared the same DMG solution but this time only added 43 ml of that to the filtered solution and got the following



Since each 43ml of DMg solution drops 1 gram of Pd, and I have used up 143 ml of DMG therefore I expect 3.39 grams of Pd

Here is the combined Pd DMG, after being rinsed throughly with hot water


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## kjavanb123 (Jun 20, 2019)

I transfered the Pd DMG salt to a much bigger plastic container as I had already experienced lots of foaming during zinc cementing.

Here is the Pd DMG salt in a larger plastic pan



Added 200 ml of hcl (31%), then sprinkled zinc powder and as expected DMG Pd salts started to bubble and foam up



I kept spraying with water then swirl the mixture, as it gradually changed color to dark green 



More agitation and a little zinc addition



Near the completion


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## kjavanb123 (Jun 20, 2019)

Here final pics


And Pd powder drying


Melting is done tommorow using acetylic oxygen gas


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## glorycloud (Jun 20, 2019)

I would like to buy you a pair of gloves to protect your skin
while you are working with these acids and salts. Would anyone
else like to pitch in and buy a pair or two to protect this nice
person from causing more harm to their body? :shock:


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## kjavanb123 (Jun 20, 2019)

Hi

Thanks, I do wear gloves, I took them off for taking the photos with my phone.

Thanks and regards
KJ


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## glorycloud (Jun 21, 2019)

But the world doesn't see that in your photos. If you take your gloves
off to take photos, perhaps you can find a way to take the picture
not showing your unprotected fingers because it gives the hundreds
off viewers of your post the impression that gloves are a nuisance
or are not necessary when refining.


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## kurtak (Jun 21, 2019)

glorycloud

the question/warning to members about waring gloves is generally asked/given to new members to inform them of the need for safety concerns

Kevin has been at this for a very long time & I am "sure" he is "fully" aware of the NEED to ware gloves during processing &/or handling chems

taking pics with gloves on is cumbersome & in fact when taking pics with my smart phone the touch screen wont even work with gloves on

looking at the pics Kevin has taken it is clearly evident he wares his gloves during processing - otherwise you would be seeing chem stains on his fingers - chem stains on the fingers "can not" be avoided during handling/processing if done without gloves - chem stains (on the fingers) is a dead give away 

I don't see any stains considering Kevin works with this "every day" so IMO its really a non issue - certainly not one that needs to be "pushed" after a proper explanation is given by an experienced member

Its more a question/warning for new members to insure they stay safe (IMO)

Kurt


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## kjavanb123 (Jun 21, 2019)

Hi Kurt

Thanks a lot for your support there. I used my finger in the pic as a reference to the size of black powder.

Yes it is almost impossible to take photos with smart phones with gloves on.

My intension for this post was to show anyone interested in Pd recovery and refining steps I have learned from this forum.

One note regarding the dried weight of Pd powder is 3.34 grams which is very close to expected Pd by adding 143 ml of DMG solution.

I hope to get all the powders melted tommorow and show the final result.

I will be processing more lots of the same box


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## glorycloud (Jun 21, 2019)

Understood. It is hard to take pictures with a smart phone with gloves.
BUT, the point remains. This is a public forum and it simply gives the
appearance that it's OK to do what we do without gloves on.

If you had never been on this forum before and you happened to stumble 
upon this thread, what would your impression be?

That is the only concern that I have. Especially when dealing with something
as truly potentially hazardous as the salts formed what you are doing. 

I will return to anonymity now.


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## kjavanb123 (Jun 22, 2019)

Hi 

I finally got to melt the powder into metals here are the results

Pd black powder weight: 3.34 grams
Silver powder weight: 1.39 grams

Pd bead after melting: 2.23 grams
Ag bead after melting: 1.36 grams

Purity of both metals are high. I am just curios about loss of over a gram of palladium depite many washes of dmg salt.

Here are some pics









And silver bead






Nexf I will be processing all of the contacts at once.

Thanks and regards
KJ


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## rickzeien (Jun 22, 2019)

kjavanb123 said:


> Hi
> 
> I finally got to melt the powder into metals here are the results
> 
> ...


Thanks. Great info. 

Sent from my SM-G950U using Tapatalk


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## anachronism (Jun 22, 2019)

Glad you got the Pd Kevin 8) 8) 

Jon


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## johnny309 (Jun 23, 2019)

It is not lost ....is in your melting dish....if you can provide a picture of your melting dish (I'm guessing covered in black...because you did not reach the temperature for melting Pd....and that I say only looking of the final product.... it is "frozen")


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## kjavanb123 (Jun 23, 2019)

johnny309 said:


> It is not lost ....is in your melting dish....if you can provide a picture of your melting dish (I'm guessing covered in black...because you did not reach the temperature for melting Pd....and that I say only looking of the final product.... it is "frozen")



Hi

I dont have the pic of the melting dish but what u see in the first two photos of Pd which was rolled to inspect any cracks which there was none which is indication of purity.

If you refer to third and foruth pics as "frozen" that is silver bead


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## kjavanb123 (Jun 26, 2019)

Hi everyone

As promised I have finished processing the entire contacts removed from a NEC telecomm box components and recovered Ag, Au, Pd and Pt

The final powders will be melting today and will post them tonight.

Here are some pictures of contacts removed manually from different components of this telecomm box, total weight is 189 grams.













Processing continued next post


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## kjavanb123 (Jun 26, 2019)

First

All components were dissolved in hot dilute nitric acid, it took almost 500 ml of nitric acidto completely dissolve Pd, Ag and other base metals.

There were gold and platinum foils plus some tin nitrate paste in the beaker.

Here is the main nitrate solution with Pd G and all base metals



The residue not dissolved in nitric acid containing tin nitrate, gold and platinum. Gold is visible with naked eyes


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## kjavanb123 (Jun 26, 2019)

First thing addition of hcl to drop silver as silver chloride, then filtering it, wash it with hot water till the passing solution is negative for any Pd.



Cementing with zinc powder washing the silver powder till pH is 7, drying.












Total weight for dried silver powder is 3.90 grams


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## kjavanb123 (Jun 26, 2019)

Ok now going at the main precious metals used in all these contacts, Palladium.



Checked with stannous and got this dark brown result



As it has been discussed in forum, there are at3 main methods of dropping Pd from a solution, which means cemeting on copper, or dropping with zinc powder, and for small or lab size using DMG. Not to mention ammonium salt follow by ammonia wash adding hcl 

I have access to a reliable yet inexpensive DMG source so I can use that for a quicker method of recovery for Pd.

I prepared a DMG solution based on the guidelines provided by R.I.P freechemists (4g NaOH, 100 ml hot water, 5.81g DMG)

Added 100ml of DMG solution to Pd solution and got the deep yellow salt.



DMG addition repeated till stannous showed negative for Pd.

Here are some photos of stannous testing on passing solution after first, and second DMG solution addition.


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## kjavanb123 (Jun 26, 2019)

The yellow salt for each step was converted using zinc powder and hcl, and black Pd powder produced from each step was washed throughly till pH showed 7.

Here is the last Pd drop added to the previous ones to be dried.


Here is the dried Pd powder from entire lot, (not including 2.23 grams Pd which was melted from 22 gram lot 1).



Total dried weight for Pd black is 8.28 grams.


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## kjavanb123 (Jun 26, 2019)

Here is the part that I have never experienced before and that is dealing with a scrap that contained both gold and platinum.

Here is AR solution of dissolving tin nitrate gold and platinum.






Here is stannous chloride test result it shows both purpule and orange.


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## kjavanb123 (Jun 26, 2019)

Diluted the AR gold platinum solution, 



Added SMB



After 2 hours, gold had precipitated



This is the gold powder hadnt gone through 3 washes with distilled water, ammonia and hcl yet



Gold powder after washes and dried weighs 0.17 gram.


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## kjavanb123 (Jun 26, 2019)

After gold was dropped, solution was filtered and tested with stannous and showed weak Pt presence.



I added zinc powder to the above solution, and this happened,



During that reaction little of sulfur gas could be smelted. I filtered everything and checked the filtered solution there was no sign of Pt.



I dissolved everything filtered in AR



All that white yellowish powder dissolved in AR and tested positive for platinum. 



Next post


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## kjavanb123 (Jun 26, 2019)

There was this piece left which everytime I boiled in AR stannous showed positive for Platinum but this wouldnt dissolve.



So I dropped the Pt black using zinc powder from the solution and will melt the powder and thatn unknown piece all together


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## kjavanb123 (Jun 26, 2019)

All

Finally finished melting the powders into metal beads

Here is palladium, 8.23 grams Pd black powder plus 2.23 grams of Pd metal,






It weighed 9.25 grams, after rolling it seemed like it cracked as can be seen here





After second melting it weighed 8.50 grams but I bought a new melting dish and return to the jewler in evening to re melt it again.

Here is for John who was interested in seeing the melting dish after second melting of 9.25 gram Pd button.


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## kjavanb123 (Jun 26, 2019)

Silver beads from entire contacts including the bead from last lot 1,







Here is the platinum from entire lot processing
Weighs 0.390 gram





Gold and refined Pd will be posted in few hours


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## kjavanb123 (Jun 27, 2019)

Hi everyone

Since the Pd bead was impure, had to dissolve it in nitric acid.

This impure Pd bead weighed 8.050 grams.

Here is a photo of back and front, you notice a yellowish tint in the first picture that seemed like gold.





So I decided to dissolve the bead in near boiling dilute nitric acid. It took 2 hours amd 50 minutes for 8.05 grams of Pd dissolve completely.




And gold which did not dissolve in nitric remained



Gold powder cleaned up by few hot water washes



More next post


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## kjavanb123 (Jun 27, 2019)

Since I had used a lot of nitric acid to dissolve Pd bead and didnt have DMG or ammonia salt to drop Pd, I added hcl to solution till it was 800 ml of burgandy Pd solution

Then I brought the solution to near boil, added small amounts of sulfamic acid to expell too much nitric which was used.

Almost took me 1 hour and 40 minutes till all the excessive nitric was gone.

Transfered the Pd solution to a bigger bucket, and added zinc powder to drop the Pd black as it can be seen here



To this



Washed the Pd black till pH was 7, dried it



Continued next


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## kjavanb123 (Jun 27, 2019)

Finally melted the Pd black powder and got this lovely Pd bead.











I like to thank the forum and its great members some of whom are not with us anymore like freechemist to give me the initial understanding about all of these.

Lastly the photos of silver and melted gold next


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## kjavanb123 (Jun 27, 2019)

Gold 0.210 gram



Silver cleaned up







Thanks and best regards


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## Yggdrasil (Mar 8, 2020)

Hi Kjavan!
I just revisited this thread, and your silver cementing just puzzled me.

You said 


> Silver chloride was filtered and washed throughly with hot water till the solution passed the filtee turn clear and stannous test showed no more Pd.
> Silver metal from cementing with zinc powder and hcl.



How did you actually do this?
What I have been seeing on the forum is either the NAOH-syrup or Iron-H2SO4 method.
Your way seem more simple and direct, also the Pd cementing directly from DMG salt, seem very direct comparing to what has been the usual outline on the forum.


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## kjavanb123 (Mar 9, 2020)

Yggdrasil said:


> Hi Kjavan!
> I just revisited this thread, and your silver cementing just puzzled me.
> 
> You said
> ...



Hi

Silver chloride can be converted to metallic silver using zinc powder as the following;

1- Wash and rinse the silver chloride till solution is clear. 

2- Add water till all silver chloride powder is covered.

3- Sprinkle zinc powder and mix it well with solver chloride powder, check the bottom of beaker to be sure no more white silver chloride is seen.

4- Slowly add muratic acid to the mix, and stir.

5- Wait till bubbling stopped, then add more hcl to make sure zinc is removed completely.

6- Wash and rinse with hot water till pH of water rinsed is 7.

7- Dry the silver metal powder and melt.

Procedure for cemeting Palladium from DMG Pd yellow salt is very similar to above, except more stirrig and smaller addition of hcl is needed due to boil over.

These methods are straight and simple.

Hope that help
KJ


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## Yggdrasil (Mar 9, 2020)

Thanks Kjavan.
Interesting that this method hasn't been covered more.
How are the losses comparing to the Lye Sugar or Iron Sulphuric method?


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## FrugalRefiner (Mar 9, 2020)

Yggdrasil said:


> Interesting that this method hasn't been covered more.



It is. A search for HCl zinc silver will turn up around 400 results. Of course, a lot aren't on point, but plenty are.

Dave


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## kjavanb123 (Mar 10, 2020)

Yggdrasil said:


> Thanks Kjavan.
> Interesting that this method hasn't been covered more.
> How are the losses comparing to the Lye Sugar or Iron Sulphuric method?



Hi

As long as zinc is mixed well with silver chloride then losses should be zero.

Best
KJ


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## Yggdrasil (Mar 10, 2020)

Dave:
I have to admit, that I did not search for the method specifically.
One of the reasons for that is the I didn't even know it existed.
Hence my comment:


> Interesting that this method hasn't been covered more.


But then again on "all" discussions here on the forum, the options outlined has almost all been: Lye-Sugar, Iron-Sulphuric or direct smelting. 
And the first page of the 400 results has either nothing to do with AgCl or points to this thread, so even if the results are plentyful they don't necesssary produce anything meaningfull, unless you know what you are looking for in the first place.
So I'm still curious why, is it cost or something else?

Kjavan:
The DMG process for Pd is that as useful for Chlorides as well as Nitrates?


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## kjavanb123 (Mar 10, 2020)

Yggdrasil said:


> Kjavan:
> The DMG process for Pd is that as useful for Chlorides as well as Nitrates?



Hi

I dont understand your question, please elaborate.

Regards
KJ


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## Yggdrasil (Mar 10, 2020)

You use it for Palladim nitrate, will it be as effective if you have Palladium Chloride?


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## kjavanb123 (Mar 10, 2020)

Yggdrasil said:


> You use it for Palladim nitrate, will it be as effective if you have Palladium Chloride?



Yes DMG solution will percipitate Pd as yellow DMG salt from nitrate as well as chlroide solutions at ph 1-2.

But due to its high prices, it is usually used for analytical purposes.

Regards
KJ


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## Yggdrasil (Mar 10, 2020)

Thanks for the information.


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## anachronism (Mar 10, 2020)

Sodium Formate is also really good for precipitating Pd. As is Ascorbic acid. 

Then again as you pointed out Ygg- since it's not "covered and established" some people consider it not worthy of discussion because they would rather discuss the established methods they used to use "back in the day" when were actually refining. Basically because they don't understand the newer methods having no experience of them.

Kevin

Good call on the Zinc. I've not tried it but heck I am going to give it a go. What's the worst that could happen.... :lol: :lol: 

Thanks 

Jon


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## Yggdrasil (Mar 11, 2020)

I hadn't heard about the Sodium Formate path.
There was a procedure where the PGM salts were boiled in formic acid instead of calcining.
I really can't remeber just where I saw it at the moment.
This is a simplified way of the same?

I remember asking a general question to the forum a few years back, about methods of precipitating PMs,
I think that one boiled down and faded out ;-)


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## anachronism (Mar 11, 2020)

Sodium Formate in water produces Formic acid with a pH of around 3.75 and shares similarities in the chemistry with that of metallic cyanides insofar as the pH determines the content of the ions in the water. 

If you raise the pH to 6 then the amount of Formate ions as opposed to Formic acid increases dramatically. 

The same analogy applies with metallic Cyanides because at pH7 most of the free cyanide is present as HCN in solution whereas at pH 11 most of the free cyanide is present as CN- (Hence why a higher pH provides a lot more safety)

You can drop out PGMs with a pH 3.75 solution of formic acid but it works much more rapidly at pH 6 as the concentration of Formate present is far higher. The Formate is the active ingredient.

I'm sure Lou will correct my Chemistry if I have missed something important (or completely fluffed it) but that is my layman's understanding of the situation.

Jon


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## Yggdrasil (Mar 11, 2020)

Thaks again my friend!
Spoken so a noob can understand it 
My regular supplier don't have it though, Formic acid on the other hand is easy.
Well I'll cross that bridge if I need to, somwhere down the road :wink:


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## Lou (Mar 11, 2020)

anachronism said:


> Sodium Formate in water produces Formic acid with a pH of around 3.75 and shares similarities in the chemistry with that of metallic cyanides insofar as the pH determines the content of the ions in the water.
> 
> If you raise the pH to 6 then the amount of Formate ions as opposed to Formic acid increases dramatically.
> 
> ...



This is true, but in many cases, it is best to have a slow release of the formate ions, if you wish to have the highest quality metal product that filters, rinses and assays the best.

OFten times it is best to boil the Pd (or even Pt/Rh) with formic acid and urea (which slowly hydrolyzes to NH3/CO2) and makes a buffered ammonium - formate reduction medium. This produces compact, granular metal products of higher purity. 

For most people's purposes, just using sodium formate, which is actually a basic salt and getting the pH in the 4-6 range will be sufficient.


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## anachronism (Mar 11, 2020)

Thanks

In all fairness I only started learning about this thanks to a video by Owltech where he was taking a silver Nitrate/Pd Nitrate solution to pH6, hydrating the Pd Nitrate which dropped as solid. Then filtering and leaving behind pure Silver Nitrate solution. Then converting the remaining solid to Pd Chloride solution whilst leaving the remaining Silver behind in the filter as Silver Chloride (not a lot.)

Then using a pH 6 with formic Acid and heat to drop the Pd.

It turns out that it's easier to get Sodium Formate over here than Formic acid and I just started reading around the topic and voila the chemistry is there.


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## Lou (Mar 11, 2020)

That hydrolytic procedure is a common one, especially with cleaning up cell electrolyte. It can be operated in reverse of course, precipitating AgCl, filtering, and then forming the hydrous oxide before redissolving in sulfuric, fuming, forming the Pd sulfito complex and decomposing in sulfuric to Pd metal. 

Also bear in mind that UHP silver nitrate is made by using a small amount of formate to free it of PGM. Pd usually comes down first at low pH.

Keep in mind you can make formic in situ with the addition of a stronger acid (it is itself a weakly basic salt).

One thing to point out is formic and its salts on heating with strong acids, particularly sulfuric, release carbon monoxide! Have a care and make sure to check the hood draft and put a detector!

All in all, much safer than hydrazine. Slower but safer.


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## rickbb (Mar 13, 2020)

anachronism said:


> Good call on the Zinc. I've not tried it but heck I am going to give it a go. What's the worst that could happen.... :lol: :lol:



Actually using zinc powder was one of the very first methods to recover silver. 100's of years old. 

It was first used on depleted photo fixers. Adding zinc powder up to 10% over the expected yield will drop mostly pure silver. IF done correctly, not correctly and you have excess zinc in your silver drop.

When continuous electrolytic recovery units were developed it put the zinc powder method out to pasture. The yield in purity and savings in HCL costs plus all that washing labor and disposal of zinc chloride waste made it a no brainer.

On small scale it's probably a good method to use. But, I'll still use the sugar lye method, I'm used to it and does not leave a metal in an acid solution to drop and dispose of.


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## anachronism (Mar 27, 2020)

I put my money where my mouth is and tried a batch of MLCC that I know to have a yield of 5.57% Pd.

I want to say firstly that I have done this as a one off to learn and understand the process as I am not wanting to deal with PGM however I felt it was a lacking my my knowledge base but it allowed me to learn new processes and precipitation with sodium Formate which in fact has a lot of other uses including denoxxing. 

I also liked the fact that it involves full conversion of the salts to metals within one container. Naturally I used my fume cabinet and full PPE but here is the Palladium metal in the filter (130mm filter) and the waste solution after conversion and settling.

Excuse the piece of detritus on the Pd- that's been removed 8) 8)


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## anachronism (Apr 2, 2020)

The Pd precipitated is extremely fine. Can anyone suggest whether Citric acid would be a good flocculant for Pd particles? 

Jon


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## Lou (Apr 2, 2020)

I would not say citric would work. Usually more boiling is indicated.


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## anachronism (Apr 2, 2020)

Lou said:


> I would not say citric would work. Usually more boiling is indicated.



Gotcha- will give that a go.


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## kurtak (Apr 3, 2020)

VERY nice Jon

Kurt


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## anachronism (Apr 3, 2020)

Thanks Kurt

One point to note. 

I know we spend a lot of time saying that XRF readings cannot be relied upon in many circumstances. I XRFed the raw MLCC and it came back with 5.55% this is why I sent a sample for assay. I simply didn't believe the result. 

The result came back near as dammit the same.


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## Platdigger (Apr 3, 2020)

"That hydrolytic procedure is a common one, especially with cleaning up cell electrolyte. It can be operated in reverse of course, precipitating AgCl, filtering, and then forming the hydrous oxide before redissolving in sulfuric, fuming, forming the Pd sulfito complex and decomposing in sulfuric to Pd metal." 
If anyone understands this sentence (besides Lou of course who wrote it"grin") and can put it in layman terms...please do.
Thanks
Actually I understand what you are saying Lou up until the fuming part.
Do you mean boil the sulfuric until fuming?


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## anachronism (Apr 4, 2020)

Platdigger said:


> "That hydrolytic procedure is a common one, especially with cleaning up cell electrolyte. It can be operated in reverse of course, precipitating AgCl, filtering, and then forming the hydrous oxide before redissolving in sulfuric, fuming, forming the Pd sulfito complex and decomposing in sulfuric to Pd metal."
> If anyone understands this sentence (besides Lou of course who wrote it"grin") and can put it in layman terms...please do.
> Thanks
> Actually I understand what you are saying Lou up until the fuming part.
> Do you mean boil the sulfuric until fuming?



My layman's understanding is that it is the process of converting a compound to another compound using the elements in water to form that compound. In this case Palladium Nitrate is converted to Hydrous Palladium Oxide in the first conversion step by raising the pH to 6. In the second step this is readily dissolved by HCl to form a Palladium Chloride solution. 

I could be wrong however I think that the same class of process is used when treating waste solutions by raising the pH to 6 and dropping out the base metals as Hydroxides but I'm sure someone could either ratify or refute that. 

I hope that's of some use to the first part of your question.


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