# Producing Fine Silver Powder



## dmquigley (Jul 6, 2010)

This is my first post on the forum and it was suggested by Gold Silver Pro to pose my questions here; GSP has been extremely helpful to date. I am new to refining. I am trying to develop a hybrid method to cast my silver figurines. The silver I have access to has purity issues and I would like to refine it so I can produce very fine silver powder of 20 microns of less. Does anyone have a refining method or methods that will allow me to control particle size and consistently produce this very fine silver powder? Thank you.


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## Barren Realms 007 (Jul 6, 2010)

dmquigley said:


> This is my first post on the forum and it was suggested by Gold Silver Pro to pose my questions here; GSP has been extremely helpful to date. I am new to refining. I am trying to develop a hybrid method to cast my silver figurines. The silver I have access to has purity issues and I would like to refine it so I can produce very fine silver powder of 20 microns of less. Does anyone have a refining method or methods that will allow me to control particle size and consistently produce this very fine silver powder? Thank you.



Dissolve it in nitric acid, drop it with salt and convert it to silver metal with water, sulfuric acid and a piece of steel. This should give you what you are looking for.


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## goldsilverpro (Jul 6, 2010)

Here's a copy of the email I sent to dmquigley yesterday. He wants to make a metal clay mixture (of which he already has a formula for) with the powder and, evidently, the particle size is important. He wants it to be sub-20 micron. I didn't suggest using a metal, such as iron, to reduce the silver because I didn't know how iron contamination would affect the final product.



> "Although I have never had the need to produce silver powder as a product, I commonly produced silver powder as an intermediate refining step. The powder was then melted into bars. In general, this involved dissolving the impure silver in nitric acid and then precipitating the silver as silver chloride (AgCl), using either hydrochloric acid or a solution of table salt (if no mercury or lead are present, this is quite selective for silver, but the AgCl must be well-rinsed to remove any traces of dissolved contaminants). The AgCl was rinsed well and then it was reduced to silver powder using a solution of sodium hydroxide (NaOH) and Karo syrup. I have no idea what the particle size of the powder was. Here are some threads on this method.
> http://www.goldrefiningforum.com/phpBB3/search.php?keywords=karo&terms=all&author=goldsilverpro&sv=0&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search
> 
> Many schemes for making silver powder involve first making AgCl (as above) and then using various means to reduce this to silver powder. Most use chemicals, but a dry method for this, using heat, is in this patent. To use this method, you would need an electronic furnace with accurate temperature control.
> ...


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## Noxx (Jul 6, 2010)

Here's a very old post of mine:

http://goldrefiningforum.com/phpBB3/viewtopic.php?t=3264

I hope it helps...


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## Barren Realms 007 (Jul 6, 2010)

goldsilverpro said:


> Here's a copy of the email I sent to dmquigley yesterday. He wants to make a metal clay mixture (of which he already has a formula for) with the powder and, evidently, the particle size is important. He wants it to be sub-20 micron. I didn't suggest using a metal, such as iron, to reduce the silver because I didn't know how iron contamination would affect the final product.
> 
> 
> 
> ...



That was my conern when I posted the reply as well was the iron in the mix but I know the silver can be run thru HCL or sulfuric acid to clean it out.


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## nickvc (Jul 6, 2010)

When I worked for Johnson Matthey we sold filed silver and gold solder powder perhaps this might be a way to get the silver powder you want,use a new clean very fine file and try,to remove any steel coming off the file use a magnet or failing you doing it yourself ask one of the big bullion dealers for a price for your spec.


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## goldsilverpro (Jul 6, 2010)

They do make woven metal screens down to 20 microns, it seems. That is probably the method used to make the 20 micron powder that is commercially available for the silver clay. If you could find a precipitation method that produced a small particle size to start with, you might get a good yield of sub-20 micron powder by running it through the screen. That's how I would first go about it since it would be the simplest way. That way, you wouldn't need stiff controls on the precipitation. 
http://www.keison.co.uk/endecotts_wovenwiremeshsieves.shtml

A photo reductant might work. Maybe Manuel can chime in here.

I noticed somewhere in the literature that sterling silver clay is desirable because it has a greater strength than pure silver. Since it is an alloy, about the only way I can think of making powder from it would be to atomize it in the molten state.


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## Palladium (Jul 6, 2010)

Could you not take the silver and inquart it with an excess of copper. Then separate the two with hcl ? Seems like the more copper you would add the more dispersed the silver would be as far as grain size once the copper is removed.


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## Barren Realms 007 (Jul 6, 2010)

I was thinking of the silver chloride method with sulfuric and steel with a stirrer that would keep the material from clumping. Either way you have to deal with a possible by product that will need to be cleaned out.


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## goldenchild (Jul 6, 2010)

dmquigley said:


> The silver I have access to has purity issues and I would like to refine it so I can produce very fine silver powder of 20 microns of less. Does anyone have a refining method or methods that will allow me to control particle size and consistently produce this very fine silver powder? Thank you.



I would say use lazersteve's thum cell to get your silver to .9999 and melt it into bars or just buy some fine silver. Then take a very fine sandpaper and sand down the bars or purchased ingots. Use an electric sander to speed up the process if possible. At least this way your silver wont be contaminated with other metals.


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## qst42know (Jul 6, 2010)

Sand paper sheds abrasive grains. 

Silver chloride reduced with lye and Karo syrup produces a fine powder doesn't it?

Where is Lou with the right way? :lol:


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## lazersteve (Jul 6, 2010)

All the silver I convert from silver chloride that has not been allowed to dry out before it is converted remains as a fine powder once it dries. You can rub a pinch of it between your fingers and it will soak right into your skin leaving a gray streak. 

I think this should be fine enough.

Steve


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## Harold_V (Jul 7, 2010)

lazersteve said:


> All the silver I convert from silver chloride that has not been allowed to dry out before it is converted remains as a fine powder once it dries. You can rub a pinch of it between your fingers and it will soak right into your skin leaving a gray streak.
> 
> I think this should be fine enough.
> 
> Steve


I was about to post the same thing. I always reduced my silver chloride with aluminum (because I had it on hand). It reduces to a sticky paste, and is so finely divided that it's difficult to handle. It was so fine that in order to melt the stuff without loss, I'd sprinkle the surface with water and tamp it tight, to a dense cover. 

Harold


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## dmquigley (Jul 10, 2010)

Thank you one and all for your posts - I am grateful for all of your input. Thanks again.


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## bagus (Jul 13, 2010)

> In general, this involved dissolving the impure silver in nitric acid and then precipitating the silver as silver chloride (AgCl), using either hydrochloric acid or a solution of table salt (if no mercury or lead are present, this is quite selective for silver, but the AgCl must be well-rinsed to remove any traces of dissolved contaminants).



I have silver nitrate solution containing dissolved mercury from silver battery batch. Can I precipitate the silver using table salt? Or should I use another kind of method? 

best regards,

Bagus


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## Juan Manuel Arcos Frank (Jul 14, 2010)

Sorry guys...I am late in this post because I was busy in the photo bussines.

A few years ago I was asked by a cuban friend for making silver powder that he needed it for ink conductor to metalize some kind of plastic...Well,that time silver powder made with Karo syrup process worked but I learned a little bit about silver powders,here is all the information.

I hope it helps.

Kindest regards.

Manuel


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## Juan Manuel Arcos Frank (Jul 15, 2010)

David:

I have received you e mail but I did not how to aswer you becasue I did not kown your e mail adress so I will answer you by here.

The patent sounds good and easy so try to research with a little bit of silver,I have never needed such a small silver powder.

If I understood well you wanted to produce silver wildlife figurines.What kind of wildlife figurines?Are they plants,insects,flowers or small mammals?Probably you need metallization processes instead of casting processes,Exactly,what do you want to do?

Kindest Regards.

Manuel

BTW,tell me your e mail,my e mail is [email protected]


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## Anonymous (Jul 30, 2010)

Sorry, I'm not certain if I should post here or start a new topic, but if one was interested in doing the same thing with Gold rather than Silver, how would one go about doing so? My interest isn't so much in recovery at this point as it is obtaining these powders cheaply, around the price of the metal. The searches I did for these powders commercially had me spending $2000 for 100 grams of gold and 250 for 100 grams of silver. I am doing a process similar to cold casting to inlay some fine woodwork, and I would much rather use Gold and Silver over brass, bronze, tin, iron, or aluminum.


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## goldenchild (Jul 30, 2010)

ajn142 said:


> Sorry, I'm not certain if I should post here or start a new topic, but if one was interested in doing the same thing with Gold rather than Silver, how would one go about doing so? My interest isn't so much in recovery at this point as it is obtaining these powders cheaply, around the price of the metal. The searches I did for these powders commercially had me spending $2000 for 100 grams of gold and 250 for 100 grams of silver. I am doing a process similar to cold casting to inlay some fine woodwork, and I would much rather use Gold and Silver over brass, bronze, tin, iron, or aluminum.



Where did you find 100 grams of gold for $2000? What purity?


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## goldsilverpro (Jul 30, 2010)

ajn142 said:


> Sorry, I'm not certain if I should post here or start a new topic, but if one was interested in doing the same thing with Gold rather than Silver, how would one go about doing so? My interest isn't so much in recovery at this point as it is obtaining these powders cheaply, around the price of the metal. The searches I did for these powders commercially had me spending $2000 for 100 grams of gold and 250 for 100 grams of silver. I am doing a process similar to cold casting to inlay some fine woodwork, and I would much rather use Gold and Silver over brass, bronze, tin, iron, or aluminum.



You must mean $2000/10 grams or $20,000/100 grams for the gold - $2000/100 g would only be about 1/2 of spot. Why not use 22-24K gold leaf? I've used it on hand-carved mahogany exterior signs for many years. $50 worth will cover about 1 to 1-1/2 sq.ft of surface area. The gold leaf lasts forever inside or outside, if you don't touch it. Neither leaf or powder will stand up to hardly any wear unless you clear coat it. Have you considered having the metals gold plated (or setting up to do it yourself)? Gold plating can be from bright to matte, light gold color to full deep color, and in many colors, similar to karat golds. If the gold plating is thick, say 2.5 microns, it will stand up to quite a bit of abuse. An ounce of 2.5 micron gold will cover about 1000 sq.in., if my math is right.


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## Anonymous (Jul 30, 2010)

You are right. I have a good memory, but it mixes things up occasionally. Here is the link for the gold powder. http://www.surepure.com/view_product.php?prodnum=2433
And I am doing a french polish finish on a jewelry box, I did not think the leaf would hold up when I started the finish. I'm not terribly experienced in any of this though, so I'm all ears for any suggestions.Thanks for the ideas.


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## qst42know (Jul 30, 2010)

How would one make a karat gold clay?

Drop fine gold and blend in silver and copper powder?

What drops copper from solution yet rinses away cleanly? NaOH again?


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## SilverNitrate (Jul 30, 2010)

See this Vid http://www.youtube.com/watch?v=zJd0EnLwt44 and
http://www.youtube.com/watch?v=pDinFP_eU7A
powder of this type is simply blended then sent thru a sieve.
I makes gold doing a similar process. 


> How would one make a karat gold clay?
> 
> Drop fine gold and blend in silver and copper powder?
> 
> What drops copper from solution yet rinses away cleanly? NaOH again?


To make a gold clay a mimimum 22k gold ingot must be grinded and milled to a very fine powder, then binder added. You can make a pure gold powder, however pure gold would be too soft to grind or file, silver and copper can't just be added because without them being alloyed, once fired the coppers will turn to oxide and the gold will remain powder.
To drop copper use iron.


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## goldenchild (Jul 30, 2010)

SilverNitrate said:


> See this Vid http://www.youtube.com/watch?v=zJd0EnLwt44 and
> http://www.youtube.com/watch?v=pDinFP_eU7A
> powder of this type is simply blended then sent thru a sieve.
> I makes gold doing a similar process.
> ...



Question.... I recently did almost 3 pounds of silver the same way you did in your first vid. I dried out my silver with a torch and got a nice bunch of cloudy white clumps. Nearly pure I would say but I'm still gonna put my now melted ingots into the thum cell. How do you dry out your silver? Silver always seems to take way more time to completely dry out.


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## SilverNitrate (Jul 30, 2010)

goldenchild said:


> Question.... I recently did almost 3 pounds of silver the same way you did in your first vid. I dried out my silver with a torch and got a nice bunch of cloudy white clumps. Nearly pure I would say but I'm still gonna put my now melted ingots into the thum cell. How do you dry out your silver? Silver always seems to take way more time to completely dry out.


Dryying is simple, once rinsed well with water, can place into pot and boil off the water. the then powder can be crushed in a blender, pestle and mortar, etc.


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## goldenchild (Jul 30, 2010)

SilverNitrate said:


> goldenchild said:
> 
> 
> > Question.... I recently did almost 3 pounds of silver the same way you did in your first vid. I dried out my silver with a torch and got a nice bunch of cloudy white clumps. Nearly pure I would say but I'm still gonna put my now melted ingots into the thum cell. How do you dry out your silver? Silver always seems to take way more time to completely dry out.
> ...




Hmmm. What kind of pot? Wont the pot burn once all the water is evaporated? And if its not stainless wont there be contamination?


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## SilverNitrate (Jul 30, 2010)

either stainless or glass. You may want to stir it ever so often to avoid hot spots, keep the heat very low as not to sinter or clump harden together. 3#s of silver powder may take 5 hrs to completely dry from moist.


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## g_axelsson (Jul 31, 2010)

Why not just put the wet silver powder in the kitchen oven at a temperature slightly over boiling point. No risk for splatter or burning and you don't need to watch over it either.

/Göran


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## goldenchild (Jul 31, 2010)

SilverNitrate said:


> either stainless or glass. You may want to stir it ever so often to avoid hot spots, keep the heat very low as not to sinter or clump harden together. 3#s of silver powder may take 5 hrs to completely dry from moist.



I see. If it would take 5 hours I would be better off just using my method with the torch.



g_axelsson said:


> Why not just put the wet silver powder in the kitchen oven at a temperature slightly over boiling point. No risk for splatter or burning and you don't need to watch over it either.
> 
> /Göran



I thought about this. Putting it in a casserole to avoid metal contamination. But my worry is if there are any traces of chemicals it would destroy the oven. 

Thanks for your ideas guys.


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## SilverNitrate (Jul 31, 2010)

goldenchild said:


> I see. If it would take 5 hours I would be better off just using my method with the torch.


Not if your objective is to aquire silver powder.



g_axelsson said:


> Why not just put the wet silver powder in the kitchen oven at a temperature slightly over boiling point. No risk for splatter or burning and you don't need to watch over it either.
> 
> /Göran
> 
> ...


Good idea can be to place it in the back part of the oven over where the pilot light is, you can set it there and forget it and after 2 days it'll be perfectly dry, however your range needs be a gas pilot type. Yes any silver spatter may leave irremovable black spots on surfaces so be careful. You can also use one of those old warming platters or tea cup warmers for small batches.


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## g_axelsson (Jul 31, 2010)

Btw, my oven is electric. I routinely use it to drive off water from cut meteorite slabs. Just put it on 120 C in the evening and in the morning it is perfectly dry.

I have no experience with gas ovens.

If you have acids left in your silver powder then you need to work on your washing technique.

/Göran


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## SilverNitrate (Jul 31, 2010)

use ammonia


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## goldenchild (Jul 31, 2010)

g_axelsson said:


> Btw, my oven is electric. I routinely use it to drive off water from cut meteorite slabs. Just put it on 120 C in the evening and in the morning it is perfectly dry.
> 
> I have no experience with gas ovens.
> 
> ...


 Nah. No problem with rinsing but. I dont know. I just dont like the idea of getting refining stuff mixed with household stuff that you use to prepare food. Think of it this way. Would you use a spoon like the one in silvernitrates video to mix a pot of soup? It would still be in the back of my mind that the spoon had all those chemicals on it no matter how many times it was washed.


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## please35 (Apr 5, 2011)

Dear all

help me to make silver powder from silvernitrate.I need shining silvr powder.
regards,
robin


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## Barren Realms 007 (Apr 5, 2011)

please35 said:


> Dear all
> 
> help me to make silver powder from silvernitrate.I need shining silvr powder.
> regards,
> robin



You can cement your silver out of your solution with copper, wash the powder till no more color change in your solution and then melt your silver.


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## please35 (Apr 5, 2011)

Dear 007

thanks but i need to make powder if possilbe by electrolyte system.I dont need solid bar.I have take out silvernitrate sponge with copper.
I need further step.
rgdds
robin


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## jimdoc (Apr 5, 2011)

please35 said:


> Dear 007
> 
> thanks but i need to make powder if possilbe by electrolyte system.I dont need solid bar.I have take out silvernitrate sponge with copper.
> I need further step.
> ...



What are your plans for this silver powder? That may help people understand what you are seeking.

Jim


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## Barren Realms 007 (Apr 5, 2011)

Ok then melt your powder into small ingots and send the silver thru a silver electric cell. This will give you silver crystals. Look in the silver section of the forum and you should find all the info you need on this. There have been quite a few posts on silver cells lately. If you don't find what you need let me know and I will find some links for you.


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## Harold_V (Apr 6, 2011)

A cell won't yield powder under any condition, so that's not a good idea. 

When silver chloride is converted to silver via the use of aluminum (and probably with iron, too), the end result is a VERY fine powder of silver. It does not look like silver, having more of a Portland cement appearance, however. Don't know if this is useful, or not. 

Harold


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## please35 (Apr 6, 2011)

jimdoc said:


> please35 said:
> 
> 
> > Dear 007
> ...



Dear Jim

Thanks.

I need WHITE silver powder and ultrafine for illuminating.Its been 3 week I am trying and didnot found.
My result so far:
when I make silver curd.its clay color.fine but not ultra fine.I clean and boil with HCL but color didnot changed.But when I rub the sponge on porcelian bowl.the side which I rub on wall is shining like diamond as Mr.Lazersteve said but not all the partical is shining.

Hope problem is clear pls suggest. me 
rgds
robin


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## patnor1011 (Apr 6, 2011)

He probably want metallic silver in sand like form. Maybe grating? :?:


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## please35 (Apr 6, 2011)

Dear sir

I need ultrafine powder for illuminatiing.As i did as lazer steve post but not shining.but I when I rub powder on porcelein wall it shine like diamond as he says.but not all particla is shining.

Pls kindly help.I am wokring day night on finding solution since last 3 weeks.

I feel I need some chemical to make it WHITE and shining.If you can pls suggest.
rgds
robin


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## please35 (Apr 6, 2011)

Barren Realms 007 said:


> Ok then melt your powder into small ingots and send the silver thru a silver electric cell. This will give you silver crystals. Look in the silver section of the forum and you should find all the info you need on this. There have been quite a few posts on silver cells lately. If you don't find what you need let me know and I will find some links for you.



I need this for illuminating so i need ultra fine white powder.pls suggest me the one.
rgds
robin


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## butcher (Apr 14, 2011)

maybe try pure silver nitrate solution concentrate this till crystals form when cooled.

I have a feeling you are trying to plate something and get shining silver, if so maybe restate the question GSP can possibly help then.


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## samuel-a (Apr 17, 2011)

please35 said:


> Dear sir
> 
> I need ultrafine powder for illuminatiing.As i did as lazer steve post but not shining.but I when I rub powder on porcelein wall it shine like diamond as he says.but not all particla is shining.
> 
> ...



Have you tried using poor, or should i say more gentle reducing agents? 
on the acidic range: 
Ascorbic acid is claimed to produce ultra fine powder (1-3.1 micron) from pure silver nitrate solutions.
Citric acid may work as well.

on the basic range:
don't mess with that...

Particle size will mainly be judged by Temp' , PH and concentration .


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## qst42know (Apr 17, 2011)

Even if you can produce the desired product, and applied it to your project, tarnish is just around the corner. The particle form would be impossible to polish.


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## butcher (Apr 23, 2011)

mirror ?


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