Can I use large chemical drums for dissolving?

[orvi]

Does it really even have to be dry wouldn’t the 2000F dry it up pretty quick?

Depends.

You must consider everything. Drying few kg of silver powder in a crucible is not the most effective way to do it. Slow heat transfer, very high evaporation enthalpy... With few kg risk of steam explosion is a real concern - not very probable, but certainly nothing very pleasant to experience.
Everybody who I know melt the cement dry. Only for batches less than half kilo, some do not dry it to the powder and melt directly (whole cake with filter paper) - saving time as this is mostly "assaying" practice, just to assume how the bigger lot will go.

What do you mean the difficulty of filtration of the cement?

Filtering is easy to the point when the equipment is easily manageable with bare hands. Biggest Buchner funel what I ever seen was 40 cm in diameter and weighed few kilograms

Depending on how you prepare the cement, it will be ranging from fluffy powder to dense powder. Filtering the solution before cementation is very advised, because presence of opalescence or insoluble metastannic from some soldering could cause formation of non-settling very fine particles.
You can easily end up with 100g of dry powder occupying volume of 50 ml or more. If this happen, for 30 kg of silver, you will need something capable of holding 15 L when filtering. Or two set-ups for say 8 L each.
Nice hack with two buckets filtering was presented above could resolve this.

If you have time, decanting is also option, but it is very slow and volume of waste to treat is immense. Not saying how you will dry the sludge at the bottom of the drum efficiently.

With 1000ozt of silver cement, you are way above the sane capacity of the regular laboratory glassware/dishes.
Slowly stepping to the field, where in commercial facility, everything is elegantly pumped via expensive resistant pumps, dryied in rotary vacuum ovens or filtered on rotating continous vacuum filtering drum with scraper blades

You must be very creative in the way how to deal with medium size production line in your garage, limited budget and tight margins. Simple operation like pouring the cement from the cementation drum to the filter is quite tricky operation, when there is hundred liters of the juice and say 30kg of silver powder. How you get the solid safely to the filter without splashing ? How you wash the solids throughly when the cake is 80 cm high ? How would you protect yourself comfortably - working with liters of AgNO3 solution, there is no way how you can protect yourself from minor splashing etc. with simple PPE - it become just matter of time. You need to resolve this, otherwise you will soon be covered with brown patches all over your body not joking. This is quite serious thing, silver nitrate stain the skin in so minor concentrations... etc

This is not meant to discourage you, but to give you the other perspective of mid-size refining
Stay safe.

 

[ssharktu17]

Depends.

You must consider everything. Drying few kg of silver powder in a crucible is not the most effective way to do it. Slow heat transfer, very high evaporation enthalpy... With few kg risk of steam explosion is a real concern - not very probable, but certainly nothing very pleasant to experience.
Everybody who I know melt the cement dry. Only for batches less than half kilo, some do not dry it to the powder and melt directly (whole cake with filter paper) - saving time as this is mostly "assaying" practice, just to assume how the bigger lot will go.



Filtering is easy to the point when the equipment is easily manageable with bare hands. Biggest Buchner funel what I ever seen was 40 cm in diameter and weighed few kilograms

Depending on how you prepare the cement, it will be ranging from fluffy powder to dense powder. Filtering the solution before cementation is very advised, because presence of opalescence or insoluble metastannic from some soldering could cause formation of non-settling very fine particles.
You can easily end up with 100g of dry powder occupying volume of 50 ml or more. If this happen, for 30 kg of silver, you will need something capable of holding 15 L when filtering. Or two set-ups for say 8 L each.
Nice hack with two buckets filtering was presented above could resolve this.

If you have time, decanting is also option, but it is very slow and volume of waste to treat is immense. Not saying how you will dry the sludge at the bottom of the drum efficiently.

With 1000ozt of silver cement, you are way above the sane capacity of the regular laboratory glassware/dishes.
Slowly stepping to the field, where in commercial facility, everything is elegantly pumped via expensive resistant pumps, dryied in rotary vacuum ovens or filtered on rotating continous vacuum filtering drum with scraper blades

You must be very creative in the way how to deal with medium size production line in your garage, limited budget and tight margins. Simple operation like pouring the cement from the cementation drum to the filter is quite tricky operation, when there is hundred liters of the juice and say 30kg of silver powder. How you get the solid safely to the filter without splashing ? How you wash the solids throughly when the cake is 80 cm high ? How would you protect yourself comfortably - working with liters of AgNO3 solution, there is no way how you can protect yourself from minor splashing etc. with simple PPE - it become just matter of time. You need to resolve this, otherwise you will soon be covered with brown patches all over your body not joking. This is quite serious thing, silver nitrate stain the skin in so minor concentrations... etc

This is not meant to discourage you, but to give you the other perspective of mid-size refining
Stay safe.

Many things to consider. I will certainly have to start with small batches and then scale up appropriately. I dindt even know about the AgNO3 staining thats definitely something to consider. Thanks again for the input!

 

[FrugalRefiner]

How would you protect yourself comfortably - working with liters of AgNO3 solution, there is no way how you can protect yourself from minor splashing etc. with simple PPE - it become just matter of time. You need to resolve this, otherwise you will soon be covered with brown patches all over your body not joking. This is quite serious thing, silver nitrate stain the skin in so minor concentrations... etc

I have to relate an experience I had. I was dissolving a small amount of silver. My back acted up on me, and I had to leave it for a bit. It got spilled and some of it ended up on a tarp. When I felt better, I cleaned up the mess. I didn't realize there was dried silver nitrate on the tarp when I handled it.

I went for a walk later in the day. It was a nice sunny day. As I got back to our house, I checked the mail box and was shocked at several large black stains on my hands. It was silver nitrate. Took days for it to disappear.

Dave

 

[snoman701]

HA

The stains are frustrating as heck. My right thumb, index and middle finger all have streaks. I wear gloves for 99% of my time in the lab. That remaining 1% got me.

But frankly, I'm not concerned about the SILVER. It's the other metals that are also in solution that are more bothersome.

I think it's funny when people come in and want to work with this stuff. Mostly because all of us look back at our younger selves and go "noooo, don't do it....here are all the things you aren't considering"

 

[silver1]

I took the back side of my glove and wiped my eye one time thinking the back side was clean.
People ask me for a week who punched me in my eye!

 

[silver1]

But frankly, I'm not concerned about the SILVER. It's the other metals that are also in solution that are more bothersome.

Nope! Never worry about pure silver at all. Matter of fact i smoke a daily dose of it. Haven't been sick in years. Now the other stuff.....
I take NAC on a daily basis just to be healthy and safe. NAC will help pull that stuff out of you.

 

[snoman701]

Nope! Never worry about pure silver at all. Matter of fact i smoke a daily dose of it. Haven't been sick in years. Now the other stuff.....
I take NAC on a daily basis just to be healthy and safe. NAC will help pull that stuff out of you.

I don't get the pleasure of pure silver very often. When I run a cell, that's the closest I get.

 

[orvi]

The stains are frustrating as heck. My right thumb, index and middle finger all have streaks. I wear gloves for 99% of my time in the lab. That remaining 1% got me.

But frankly, I'm not concerned about the SILVER. It's the other metals that are also in solution that are more bothersome.

I think it's funny when people come in and want to work with this stuff. Mostly because all of us look back at our younger selves and go "noooo, don't do it....here are all the things you aren't considering"

I found staining myself most probably like this:
1. properly wearing gloves all day long, working with buckets, siphoning, mixing, decanting, filtering etc...
2. realizing i have dirty gloves on, touching every item and transfering the silver nitrate on everything in minute ammounts.
3. when drying the powder, i start the cleanup - also with gloves, knowing about this phenomena
4. forgetting about some ONE thing that I touched - and putting my bare hand on it
5. thinking how this could happen to me everytime i do silver

I was exactly like this. Head first to my first batch of contact points. Going with few hundred grams to see how things go ? Noooooo. Straight 3 kg and as I commited this decision, all of the things what can happen to novice happened in row.
Nearly runaway reaction, experiencing how much NO2 (and how quickly) is produced when 3 kg of mainly copper/zinc is dissolved in nitric , filtering 8-10 liters of juice with fritted glass of 300 ml capacity..., not getting the clear liquid and going straight to cementation, settling the silver mud with flocculant for 2 days, ending up filtering it anyway, realize that this isn´t possible to filter in human lifetime, deciding to redissolve the mud with nitric, now experience runaway reaction , clean it up, drop the silver as chloride with salt, nearly another runaway when doing lye/sugar method... And my first kilogram of silver was born. Also wishing I had experience to stop my younger self from doing it

 

[Yggdrasil]

Hehe, good to look back and cherish the memories of past follies.


Sometimes this little troll guy, named Murphy, just have to be sitting on your shoulder.
When things that you could swear never could happen in a million years, just happen three times in a row.
Unless that is what you want to happen, then it would take a million years.

 

[Buckly]

I have access to 55g chemical drums they are food grade used to hold acids for cleaning.

Also, as far as nitric acid everyone says 67-70% but what if I have access to 25% or 30% at a much lower cost? Are there impurities or is it just more dilute. Considering the first step in dissolving silver is diluting the acid 50% why not just start with 35%?

It depends what the grade of the 25-30% is. Should be fine (if good graded), just take longer...

 

[Racoon]

I have seen people running the reaction in 5g buckets so I thought it might be fine.

Any specific contaminants to watch out for? The drums are HDPE resin.

Using 55 gal. Drums seems to me over kill, unless you’re doing multiple pounds of silver at a time and even then you miss out on the enjoyment of seeing the reaction.

 

[orvi]

Using 55 gal. Drums seems to me over kill, unless you’re doing multiple pounds of silver at a time and even then you miss out on the enjoyment of seeing the reaction.

Doing multiple pounds is exactly what was intended and started whole discussion.

 

[kurtak]

Using 55 gal. Drums seems to me over kill, unless you’re doing multiple pounds of silver at a time and even then you miss out on the enjoyment of seeing the reaction.

As orvi pointed out - in this thread we are talking about working on a larger then hobby level - MUCH LARGER

Kurt