Micro stripping cell

[Geo]

I post this as an observation and not as a recommendation. Concentrated sulfuric acid that has a carbon colloid contamination can be cleared by doing this process : WARNING Heating concentrated sulfuric acid is very dangerous and should only be done after studying and understanding the dangers involved. Dilute the sulfuric acid by adding the acid SLOWLY to an equal amount of water. Use a glass vessel that can withstand the high temperatures created when diluting the acid. Once the acid is diluted, place the container on low heat and cover loosely. Be prepared to spend some time. when the volume of solution reaches the volume of sulfuric acid used, turn off the heat and let it cool. The carbon will congeal and settle leaving the solution clear with a light yellow tint.

By covering the container, it will double the evaporation time but the safety factor pays off in the long run. You can also use the cover as an indicator of when the solution is concentrated. when condensation stops forming on the glass, it should work for a stripping cell. Of coarse measure your acid to know your starting volume but remember, when sulfuric acid reaches a concentration of 98%, it will start evolving sulfuric fumes that is very harmful to your long term health. by heating slowly and by stopping the evaporation short, you can still use the acid for a stripping cell.

 

[nickvc]

I post this as an observation and not as a recommendation. Concentrated sulfuric acid that has a carbon colloid contamination can be cleared by doing this process : WARNING Heating concentrated sulfuric acid is very dangerous and should only be done after studying and understanding the dangers involved. Dilute the sulfuric acid by adding the acid SLOWLY to an equal amount of water. Use a glass vessel that can withstand the high temperatures created when diluting the acid. Once the acid is diluted, place the container on low heat and cover loosely. Be prepared to spend some time. when the volume of solution reaches the volume of sulfuric acid used, turn off the heat and let it cool. The carbon will congeal and settle leaving the solution clear with a light yellow tint.

By covering the container, it will double the evaporation time but the safety factor pays off in the long run. You can also use the cover as an indicator of when the solution is concentrated. when condensation stops forming on the glass, it should work for a stripping cell. Of coarse measure your acid to know your starting volume but remember, when sulfuric acid reaches a concentration of 98%, it will start evolving sulfuric fumes that is very harmful to your long term health. by heating slowly and by stopping the evaporation short, you can still use the acid for a stripping cell.

Better still buy it concentrated if at all possible, hot concentrated sulphuric is one nasty acid!

 

[sharkhook]

Thanks guys, I am still debating on which way to go with the acid as I am spending more of my time studying the next steps for cleaning up the sediment. I have concentrated sulfuric acid before and it worked although I was as nervous as a long tailed cat in a rocking chair shop. I am working toward the charman plug idea but then again still not sure i have everything needed for that step. A decent funnel, with the ability to handle the sulfuric is what I need now.

EDIT: spelling correction

 

[bmgold2]

Thanks guys, I am still debating on which way to go with the acid as I am spending more of my time studying the next steps for cleaning up the sediment. I have concentrated sulfuric acid before and it worked although I was as nervous as a long tailed cat in a rocking chair shop. I am working toward the charman plug idea but then again still not sure i have everything needed for that step. A decent funnel, with the ability to handle the sulfuric is what I need now.

EDIT: spelling correction

I just used a regular plastic funnel when I filtered my dilute acid along with a coffee filter. I got a lot of gold powder stuck in that filter but the funnel held up fine. The one I used came with an electroplating kit but I'm pretty sure a dollar store plastic kitchen funnel would work. I'll bet it would work with the concentrated acid too but I've never tried it.

The charmin plug would work for the diluted acid but the fiberglass plug should work with the concentrated acid. Check out this thread - http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=49&t=16388

Might need to vacuum filter it, I never tried it yet but even if you diluted the acid first, it should save getting the gold stuck in the filter since you can just process the fiberglass and when done, reuse it again.

 

[sharkhook]

That is a great post and I have read it several times. But, one more time helped, Thanks. I was forgetting the dilution part. We are looking at some bad weather the next few days, so it will have to wait a bit, but I will be trying it soon.

 

[bmgold2]

I tried the fiberglass plug using some insulation and my little plastic funnel to filter the concentrated acid from my micro cell. It worked fine with the concentrated acid but, since most of the gold powder had already been removed, I didn't get enough to bother with yet. Then I re-filtered the diluted acid that still had a little powder in it that the coffee filter missed through the same fiberglass plug and it caught that little bit of fine powder as well as diluted the little bit of concentrated acid left in the plug. I don't have a vacuum filter so just let gravity do the work. The concentrated acid was kind of slow but not too bad. I'd say this is the way to do it if you want to reuse the acid without evaporating the excess water off it. Should be much easier to deal with the little bit of fiberglass instead of the coffee filter and it looks like it did a better job.

My dark colored concentrated acid is still dark so I expect that it is going to stay that way unless I dilute it and evaporate off the water but I just don't want to deal with hot sulfuric acid yet. Maybe someday but it just sounds more dangerous than I am set up to deal with at the moment. It is still kept separate just in case.

 

[sharkhook]

I had a funnel I had forgot about, it is plastic, but I put a drop of sulfuric on it and it seems to be holding up just fine. The nice part is it will easily hold the entire contents of my little cell, and then some. It is fairly windy outside now, so I will wait until the weather clears then try it with the fiberglass. I am pretty sure it will work, (to many on the forum have to much success to believe it wouldn't work). I tired an experiment with HCl/CL to get a feel for it, but my stannous had gone bad, so I am making a new batch just for this. Even then I picked up some good first hand experience with the test. I now have the stuff to make up the Poor man's AR, so I may go that route. If nothing else it will be some new experience that could be helpful later on.

And for anyone who is new at this that may be reading this, go slow when mixing the HCL and CL. It will fizz and even pop and spatter if you get in a hurry, just don't rush it. I didn't have the spattering, but then I went very slow, and it will fizz pretty strongly. I would do a very small amount, I used three teaspoons of HCL and slowly added 1/2 teaspoon of Clorox for my testing. Just be extra careful with any of this stuff, it can be very bad if you have an accident.

 

[bmgold2]

This may not be the right place to post this since this 2nd gold bead wasn't from the gold stripping cell but I thought I'd keep both of my beads so far in the same thread.



Again, it's not the best picture but it was the best one of the group that I took. I already put the tiny bead in a coin holder so that made it even harder to get the picture.

This bead is maybe 1/10th the size of my first one. As close as I can come, it is around 20 mg. but much purer than my first one. I can't tell for sure if it has a pipe or if what I can see (not in the picture) is just a pocket from the borax. The color is much brighter and the original powder was a lighter color.

This is proof that you can start with very small amounts for a test and still end up with a bead of gold. There are still some even smaller beads left in my melting cupel that didn't join with this bead. I'll either dump them out and reprocess them next batch or just leave them there and hope they get caught with the next bead.

Now all I need to do is move up to larger batches so I can get a bigger piece of gold. Maybe when it warms up a little more.

 

[Geo]

Add a little baking soda to your flux next time. i found that using the lens from high grade optics also thins the flux. LENS? what am i talking about? well, the lens in high grade optics is actually made from flourspar = flourite. http://en.wikipedia.org/wiki/Fluorite

grind or mill the lens to dust. DO NOT BREATH THIS DUST! mix the powdered glass with the baking soda. This is hard on the crucible but it will thin the flux so that even the tiny prills of gold will come together in a process called "Coalescence" http://en.wikipedia.org/wiki/Coalescence_(chemistry)

 

[bmgold2]

Add a little baking soda to your flux next time. i found that using the lens from high grade optics also thins the flux. LENS? what am i talking about? well, the lens in high grade optics is actually made from flourspar = flourite. http://en.wikipedia.org/wiki/Fluorite

grind or mill the lens to dust. DO NOT BREATH THIS DUST! mix the powdered glass with the baking soda. This is hard on the crucible but it will thin the flux so that even the tiny prills of gold will come together in a process called "Coalescence" http://en.wikipedia.org/wiki/Coalescence_(chemistry)

Baking soda I have. Sodium carbonate (washing soda) I have. High grade optics I don't have. I did find a few companies that sell fluorite (pottery supply places) for $3 or $4 a pound but haven't been able to find out the shipping cost yet.

What kind of high grade optics are you talking about? Anything easy and cheap to find?

Being hard on the crucible isn't an issue since I have only been using cupels so far and they are usually a one or two shot deal. I only have a few new ones left though so I will probably have to get a real melting dish eventually. My actual plan is just to start working with slightly larger quantities of gold before I melt and hope that the larger bead will collect all the gold. I am having fun and gaining confidence by processing and melting small amounts of gold. It's hard to tell from my two pictures of my first 2 beads but the second one is much better. I can't say for sure that it is pure (.999) yet but it must be getting closer.

 

[Geo]

Recycling usually generates a lot of non metals. Expensive (when new) optical lens from cameras, telescopes or microscopes, lens from micro imaging readers. It may or may not be easy to determine from appearance but by crushing all the lens that you find should ensure that you have some in the mix. I dont think that optical glass thats not fluorspar will hinder the thinning of the flux.

 

[bmgold2]

Recycling usually generates a lot of non metals. Expensive (when new) optical lens from cameras, telescopes or microscopes, lens from micro imaging readers. It may or may not be easy to determine from appearance but by crushing all the lens that you find should ensure that you have some in the mix. I dont think that optical glass thats not fluorspar will hinder the thinning of the flux.

Thanks Geo,

I'll keep my eye out for cheap or free stuff. I'm a bit of a pack rat and have many hobbies. I'd have a hard time crushing up good lenses but maybe I'll run across some scratched up ones. I'll bet a pound of the fluorite would last me a long time so that might be my best bet.

 

[sharkhook]

I built a quick stand for filtering my cell acid. Not to fancy but it worked well enough. I noticed more pins fell from my basket, but that is OK, this time. The removed acid had no sediment that I could see, so the charman plug seemed to work quite well.







EDIT: Forgot the pictures.

 

[necromancer]

LENS? what am i talking about? well, the lens in high grade optics is actually made from flourspar = flourite. http://en.wikipedia.org/wiki/Fluorite

can you post a photo of this lens + what the lens came out of please



i love recycling its as free as free can get

 

[Geo]

http://www.bing.com/images/search?q=fluorite+lens&FORM=HDRSC2

http://www.bing.com/images/search?q=microfilm+reader+lens&go=&qs=n&form=QBIR&pq=microfilm+reader+lens&sc=0-17&sp=-1&sk=

http://www.bing.com/images/results.aspx?q=projector+lens&x=0&y=0&form=MSNH14&refig=116c7346a4644b709a6f68f8148bd91a&pq=projector+lens&sc=8-14&sp=-1&qs=n&sk=

 

[necromancer]

Thank You Geo

 

[sharkhook]

A bit weak, and may have some copper in it still. But I got this far today.



And the (fresh made) stannous test.



This has been some journey, with more to come, I am sure. Thanks, everyone involved.

 

[niteliteone]

Good job 8)
Color doesn't look bad at all especially considering your experience working with a de-plating cell

 

[bmgold2]

Looks good so far. Hopefully you get more gold than I did from my first try with this gold stripping cell.

One thing I did that wasn't quite right was to use a glass peanut butter jar to precipitate my gold in. The problem was the jar wasn't smooth at the bottom of the sides. The gold powder tended to stick to the glass instead of all settling to the bottom. I did get most of it but that jar still has a little bit of powder in it. I reused that jar to decant other washing liquids into to catch any fine powder that got poured off. There isn't much and I'll eventually get it but I got some real beakers off of Ebay to use now. I'm still only doing small tests so the beakers are small (50 mL, 100 mL, and 250 mL for only $8). Each one now has something in it except for the largest one. I really should move up to processing larger amounts but these small tests are allowing me to test out the different processes without risking a lot of gold. They just don't result in very much gold to melt.

Keep us posted on what you end up with from you efforts.

 

[sharkhook]

What is in the jar (flower vase) is about 50 percent water from rinsing the filter. It isn't as big as it looks as it is holding about ten cups of combined water and concentrates. After settling over night there is a very fine, very thin layer of white sediment on the bottom. I am still deciding on which way to go with it, but will be doing a second refine on it, most likely I will use a small amount of AR for the second run. I just need to get some good washing for the first drop done. Still trying to hold back the urge to rush it, but it is to far along to hurry up and miss any steps at this point. I did do something I haven't been able to find anything on the forum about, so here goes. While waiting for the powders to dissolve, I stirred it using broken pieces of plates with gold leaf, some were fairly thick and took some time to come off. I now have some extra room for my storage area, but still have quite a few more plates and glasses. The rinse from the plates is part of the extra rinse water I added in when the filter was clean.