# SOLVED -I Need Help With Black Powder After Washing It Clean



## Anonymous (Jan 28, 2013)

Hello members,

I have been running my sulfuric cell for my gold recovery and it has been without any problems at all. However, I'm stuck at a certain point and I need some advise. 

*No# 1.* Since this batch is only 8 grams of black powder, how much hydrochloric acid am I supposed to use? By the way, I simply used 70 ml of it and it completely covered the black powder that is still in a pyrex dish. I started to transfer the powder first, but I noticed that after the incineration I did on the filter and powder last night, alot of residue was stuck to the dish, so I decided to just add the acid to the dish, instead of the transfer first.

*No# 2.* How long does the acid need to sit in the dish before I can transfer it? I noticed that the dish was still letting off steam/fume/gases after I added the solution approximately an hour ago. 

*No# 3.* Once the solution cools down, do I transfer it to a beaker, then decant the acid out, then add more acid, then add heat to it? Once I add heat to it, how long must I keep the heat going?

I've been rereading this thread here, the 2nd post on page 5. I'm now at *step 12*:
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=52&t=7093&start=80

Other than the above questions, everything is going well, without any problems at all. Hopefully, I won't have any more questions and I can then just pop up a gold button in the "*Gallery*", but I'm sure I may need to ask more questions to make sure I'm doing everything correct, plus I want to be able to say that I refined e-scrap and made a gold button. 


Kevin


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## butcher (Jan 29, 2013)

How much acid really depends on if you are dissolving gold with aqua regia or the hydrochloric acid and bleach method.

Hoke's book say's it takes approximately 4 fl. oz. HCl and 1 fl.oz. HNO3 to dissolve a troy ounce of gold.
Or 118.29 ml HCl and 29.57 ml HNO3 to dissolve a troy ounce of gold
This amount of acids divided by 31.103g/t.oz gives us:
3.8 ml HCl and 0.95 ml HNO3 to dissolve a gram of gold.
So if you have 8 grams of gold you would need about:
30.4 ml HCL and 7.6 ml HNO3 to dissolve 8g of gold, measure out Hno3 and add it in small amounts as needed until gold is dissolved (using heat) so you can use up nitric, without having excess in solution with done, you may find you can get by with less nitric than the calculated amount.

If using HCl/bleach to dissolve the gold, you will need a little more HCl per gram than this as the bleach will neutralize some of the acid.

The HCl/ bleach method is easier if you are not used to dealing with aqua regia.


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## Anonymous (Jan 29, 2013)

butcher said:


> How much acid really depends on if you are dissolving gold with aqua regia or the hydrochloric acid and bleach method.
> 
> Hoke's book say's it takes approximately 4 fl. oz. HCl and 1 fl.oz. HNO3 to dissolve a troy ounce of gold.
> Or 118.29 ml HCl and 29.57 ml HNO3 to dissolve a troy ounce of gold
> ...


Thanks, that gave me a better understanding, which raises another question.

Do I need to add bleach to the HCL? I never added any at all. And do I do the same thing once I transfer to the beaker and decant and filter the solution?

Kevin


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## philddreamer (Jan 29, 2013)

Kevin, if you add some bleach you will dissolve the black powder and then just proceed with the steps of precipitaing your gold with SMB.
Take care!
Phil


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## Anonymous (Jan 29, 2013)

philddreamer said:


> Kevin, if you add some bleach you will dissolve the black powder and then just proceed with the steps of precipitaing your gold with SMB.
> Take care!
> Phil


Got it!... Thanks Phil.

Kevin


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## Anonymous (Jan 29, 2013)

Am I not doing something right?

I added bleach to the hydrochloric acid, which my black powder has been in since last night. I added heat to it, but it doesn't seem to dissolve the black powder?

How long, on average, should the HCL-CL take to dissolve the powder I have, which is approximately 8 grams? So far, it's been approximately 15 minutes the powder has been on low heat.

Kevin


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## Palladium (Jan 29, 2013)

Is that a pyroceram dish or does it just say pyrex?


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## resabed01 (Jan 29, 2013)

testerman said:


> Am I not doing something right?
> 
> I added bleach to the hydrochloric acid, which my black powder has been in since last night. I added heat to it, but it doesn't seem to dissolve the black powder?
> 
> ...



You don't heat your solution when adding bleach to the HCL. This goes against trying to keep chlorine in solution for converting your gold powder to gold chloride. If you heat the solution, it will drive the chlorine out before it's had the chance to do the conversion.

Your solution should be room temperature or cooler. Add small increments of bleach and stir well.... give it time. Maybe an hour before adding a bit more.

Keep in mind, there may not be much gold even though it looks like there is. Black in your solution could also be dirt & trash.


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## Anonymous (Jan 29, 2013)

Palladium said:


> Is that a pyroceram dish or does it just say pyrex?


My internet is down right now. I'm using my phone.

This is the dish I'm using. I have Pyrex dishes, but I don't think this dish is.

Sorry, but I don't know how to resize pictures on this phone.




*[UPDATE]*
Internet back up, plus I added the word in red above.


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## FrugalRefiner (Jan 29, 2013)

Kevin,

STOP!! Do NOT heat that dish on that burner the way you have it in your photo!

1. That dish is not rated for stove top use, which is what you are doing using it directly on the heating element.

2. The coil type burners are not the best choice for heating any type of dish, including stove top safe types, because they create hot spots on the coils and leave cool spots in between. This can easily lead to thermal shock induced failure of your dish.

3. Always put your primary vessel inside a secondary containment vessel so if your reaction vessel fails your acid and values are not lost into your hot plate.

Others will probably add further advice but I want to stop you as fast as I can.

Dave


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## Palladium (Jan 29, 2013)

Best $35 you will ever spend. You can heat these any way you want to. I have even used a blow torch on these things.
http://www.ebay.com/itm/Lot-of-5-Corning-Ware-Blue-Cornflower-Bake-Dishes-PYROCERAM-Modern-made-USA-/200886377657?pt=LH_DefaultDomain_0&hash=item2ec5c2dcb9


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## Anonymous (Jan 29, 2013)

FrugalRefiner said:


> Kevin,
> 
> STOP!! Do NOT heat that dish on that burner the way you have it in your photo!
> 
> ...


Thanks for the advise Dave, yet, at the time I uploaded that photo, I had already turned it off. 

The dish IS a Pyrex. I confirmed it after checking on the powder.

I do have a more dishes I can put that in. I have been looking for one of the hot plates that's solid all the way around. I do like them better too, and I've seen more people using them than the kind I'm using. I'll upgrade soon. I'm also going to transfer everything in my beaker, then put the beaker in that dish (with some water added) to make sure that if the beaker breaks, it'll be contained in the pyrex dish.

What comes to mind is that there are different methods of doing this, and from the Tutorial I've been reading, I should be using Nitric Acid along with the HCL to dissolve the powder, yet, others use bleach with the HCL. I will learn more about each method, as I have plenty of gold plated material to work with. I'm just wondering how to process this batch, for my first time, safely and quickly, so that way, by reading up on other methods, I can have a better understanding and can try other methods to see which works better for me.

Right now, the powder haven't dissolved, so, I'm needing to rethink what I need to do next. It's approximately 2 hours now since I added bleach and heat to the HCL. 


Kevin


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## Anonymous (Jan 29, 2013)

Palladium said:


> Best $35 you will ever spend. You can heat these any way you want to. I have even used a blow torch on these things.
> http://www.ebay.com/itm/Lot-of-5-Corning-Ware-Blue-Cornflower-Bake-Dishes-PYROCERAM-Modern-made-USA-/200886377657?pt=LH_DefaultDomain_0&hash=item2ec5c2dcb9


I'm going to look into buying some Corning Ware too. I see they do hold up good to flames and heat. I guess they're more of a ceramic than glass.

Thanks for the info.

Kevin


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## FrugalRefiner (Jan 29, 2013)

testerman said:


> The dish IS a Pyrex. I confirmed it after checking on the powder.
> 
> I do have a more dishes I can put that in. I have been looking for one of the hot plates that's solid all the way around. I do like them better too, and I've seen more people using them than the kind I'm using. I'll upgrade soon. I'm also going to transfer everything in my beaker, then put the beaker in that dish (with some water added) to make sure that if the beaker breaks, it'll be contained in the pyrex dish.


Corning's Pyroceram and Visions cookware are the only kitchen glass suitable for stove top use. The pyrex dish you have is only suitable for oven use. It is not recommended for stove top use, whether or not there is any liquid in it.



> What comes to mind is that there are different methods of doing this, and from the Tutorial I've been reading, I should be using Nitric Acid along with the HCL to dissolve the powder, yet, others use bleach with the HCL. I will learn more about each method, as I have plenty of gold plated material to work with. I'm just wondering how to process this batch, for my first time, safely and quickly, so that way, by reading up on other methods, I can have a better understanding and can try other methods to see which works better for me.
> 
> Right now, the powder haven't dissolved, so, I'm needing to rethink what I need to do next. It's approximately 2 hours now since I added bleach and heat to the HCL.


2 hours seems too long. Aqua regia (HCl + HNO3) is much faster than HCl / Bleach, but for powders, the HCl / bleach should still work.

Have you tested your solution with stannous to see if you have any gold in solution?

How much HCl and how much bleach have you used? You may need to add more of one or both.

As resabed suggested, the remaining powder may be other materials that were dissolved into your cell as you were getting it tweaked. Copper comes to mind as you mentioned your basket was suffering some degradation.

If your solution tests positive, I would be tempted to let it settle, then decant the pregnant solution to another beaker. Then add some fresh acid to the remaining solids and add some fresh bleach. Then test the new solution.

Hope this helps,
Dave


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## Palladium (Jan 29, 2013)

If it's good enough to go on the tip of a missile i will use it any day. :mrgreen: 
http://www.corning.com/lifesciences/us_canada/en/technical_resources/product_guid/shp/pyro.aspx


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## Anonymous (Jan 29, 2013)

FrugalRefiner said:


> testerman said:
> 
> 
> > The dish IS a Pyrex. I confirmed it after checking on the powder.
> ...


I tested the solution with stannous, and the q-tip turned completely black. After 3 minutes, it's still completely black. So, there is gold in the solution. The solution is between a dark yellowish/greenish color. But on the q-tip, the solution is yellow.

I first added 70 ml of HCL yesterday, then today I added approximately 50 ml of bleach. Then I added about 30 ml more HCL to make it a total of 100 ml.

So, what I'll do is decant the solution, then add "just bleach to the solids/powder"? If there is still gold in there, how will I know by just adding bleach? Would I need to add HCL + Nitric to let it dissolve the solids?

So far, I feel alot of progress is being made, because of the help I'm receiving, plus the understanding I'm gaining as I go along. This is very interesting to do.

Kevin


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## Anonymous (Jan 29, 2013)

Palladium said:


> If it's good enough to go on the tip of a missile i will use it any day. :mrgreen:
> http://www.corning.com/lifesciences/us_canada/en/technical_resources/product_guid/shp/pyro.aspx


Nice... Very Nice! I gotta get me some. I know some are at the GoodWill store here. I'll definitely look for some of them.

Thanks

Kevin


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## butcher (Jan 29, 2013)

The yellow solution is gold chloride (the green in it is copper chloride), let what you have sit, until the solution clears (no murky look to solution) decant the clear yellow (slight green) filter this liquid to a clean vessel, let this vessel sit in the sun to help drive off free chlorine, we will precipitate gold in this vessel later.

The remaining powders which may contain undissolved gold add more HCl acid, add a little bleach and stir, let powders react, as the chlorine is used up add some more bleach and stir again to dissolve more gold into solution.

We need to keep the solution acidic to dissolve the gold (as stated earlier bleach will raise the pH towards neutralizing the solution), you can monitor pH, or just make sure you have excess HCl acid in solution.

Note also before precipitating the gold we will need to be sure we do not have free chlorine in solution, here is where heating, or sitting in the heat of the warm sun can help to drive off the free chlorine out of solution before trying to precipitate your gold.


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## Anonymous (Jan 29, 2013)

butcher said:


> The yellow solution is gold chloride (the green in it is copper chloride), let what you have sit, until the solution clears (no murky look to solution) decant the clear yellow (slight green) filter this liquid to a clean vessel, let this vessel sit in the sun to help drive off free chlorine, we will precipitate gold in this vessel later.
> 
> The remaining powders which may contain undissolved gold add more HCl acid, add a little bleach and stir, let powders react, as the chlorine is used up add some more bleach and stir again to dissolve more gold into solution.
> 
> ...


Before you made this post, I had already added the smb after doing a stannous test. Below are some pictures I took just a few minutes ago.










I can see some black buildup on the bottom (sorry I didn't take a picture of it), but the sediment from the SMB is what I see most of. I believe I used approximately 10 tsp of SMB, slowly, 1 tsp at a time until it started to change. Did I add enough? Every time I add some (1 tsp at a time) it fizzles in the solution. It started getting dark outside, so I put it up, not knowing if I actually finished the dropping of the gold.

It's getting windy outside, although it's around 65F, they are predicting heavy rain tonight, and possibly tornadoes. 

I'm going to do something to somebody if it blows all my stuff away. :twisted: It's in my drawer and closed. 

Once I get one method of what I'm doing down-packed, I'm going to do it again to make sure I'm doing it correct, then I'm going to learn more on other methods of doing the same thing and determine which is better for me.

Once again, I love you all for all the help you've been providing, and it's been a "*Never forgetting Experience*".

Kevin


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## butcher (Jan 29, 2013)

The green solution has a lot more copper mixed with your gold than I suspected.

Remember if you have free chlorine your gold will redissolve, which can create a problem of using too much SMB to try and precipitate the gold.

Use the stannous chloride test to determine when you have enough SMB and the gold has preciptated from solution.

The Picture after SMB looks to have undissolved salts, and the color is closer to what I would expect to see a gold solution without copper, I also see no green from copper in solution, if this is the same solution, it looks like you also precipitated the copper, things are not looking right here, you may have used way too much SMB.


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## Anonymous (Jan 29, 2013)

butcher said:


> The green solution has a lot more copper mixed with your gold than I suspected.
> 
> Remember if you have free chlorine your gold will redissolve, which can create a problem of using too much SMB to try and precipitate the gold.
> 
> ...


The golden solution in the picture above, I just took another stannous test, and the results are exactly the same as the first picture. I can upload the picture of the q-tip, but it looks exactly like the other one in color. It's blackish/dark purple.

I know one thing for sure, and that is I didn't know what the exact ratio of HCL-CL to add for the amount of powder I was working with. Hopefully I didn't mess things up, but gold is still testing positive in the solution, which should mean that I haven't dropped all of the gold, if any, at all.

If it helps any, I didn't add any water at all to the solution.

Kevin


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## butcher (Jan 30, 2013)

You could also be seeing a false positive test for gold, which will happen if you use way too much sodium metabisulfite.

The green color being gone from solution after using SMB is why I suspect this is the case, the gold should precipitate from solution before the copper.

The other thing, which may just be a remote possibility is you still have chlorine gas in solution, although I doubt this is the case if the stannous chloride is able to reduce the gold to give you the violet color in your test.

At this point I would take a stannous chloride test.
A trick I have used to test the color, if the color was very dark (almost black), is to hold the Qtip over a solution if HCl I was heating driving off oxidizers (nitric from aqua regia or bleach from HCl/NaClO), the steam from this solution will lighten the color on the Qtip that may look almost black and reveal the true purple color of the stannous test. 

You may also try taking a few drops of liquid dilute it with water and retest it to get a lighter color to your Qtip to see if it is a brown or a purple (not a very dark color almost black, that is hard to tell if it is violet or brown or what).

You could also try heating the solution to see if gold will precipitate (this and using your stannous test).

And then there is cementing with copper this will cement gold if it is in solution, and will not hurt anything if it is not.

From the pictures and your description it just makes me think something went wrong.


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## tek4g63 (Jan 30, 2013)

Kevin,
I completely agree with butcher.

It seems that you may have used too much bleach at the start. And that much SMB I'm sure is way too much.

With HCL/CL the key is to add your bleach in very little amounts at a time. While continually stirring and waiting for the bleach to complete its task before adding more. I once dissolved nearly a Troy ounce of powder with HCL bleach in one jar. I looked at the formula in Hoke's book for AR to dissolve one ounce and because I was using bleach instead of nitric I knew that o would need about ( just a guess ) 15% more HCL because the bleach will mess with the pH. I then began to stir the solution and added bleach one cap full at a time, stirring and waiting about 15 min in between additions of bleach. If my memory serves me right, it only took like 3 or 4 cap fulls. Not much bleach at all.

Once all the gold was dissolved, I placed the container on an old coffee maker heater and let it sit there hot for a couple of hours. Then I let the solution cool to room temp and added a couple of hand fulls of ice. The ice will act to cool the solution as well as dilute it a bit. The cold gold chloride will not be able to hold any silver or lead if present and it will drop out as a white powder. Filter the cold solution into a clean beaker and its time to drop the gold.

You only need to use a bit more SMB than the expected weight of the gold to be dropped. So if you thought there may be 8 grams of gold, you shouldn't have to add more than 8-9 grams of SMB. Now if you still have chlorine in solution it could take a bit more SMB to get the gold to stay dropped.

Be patient with your solution after adding SMB. Because some times you get a nice fast drop or change in solution, but allot of times it can be quit slow and could even take several hours.

I hope that I was able to explain that clearly. I'm not as good with words as butcher is.


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## butcher (Jan 30, 2013)

tek4g63
:lol: I just wish I could say it that well.


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## lazersteve (Jan 31, 2013)

Your precipitate looks to be a mix of copper one chloride, miscellaneous salts, and gold. This happens when you have dissolved copper two chloride mixed with your dissolved gold solution and add too much SMB as mentioned above. The problem of CuCl mixed with gold powder is very easy to fix. 

1) Filter out the solids.
2) Flush the solids with lots of hot water.
3) Treat the solids with an excess of full strength 31%+ HCl with lots of stirring. This dissolves the copper I chloride into the acid coloring it dark brown to black.
4) Allow to settle and decant or filter the solids out again, the solids contain your gold powder.
5) Incinerate to red heat if desired.
6) Dissolve the dirty gold powder again (straw yellow to orange solution this time ), filter until 100% transparent, and precipitate with the proper amount of SMB.
7) Left over solutions should all be gently heated until the smell of SO2 is gone, then tested for dissolved Au.


Steve


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## Anonymous (Feb 13, 2013)

lazersteve said:


> Your precipitate looks to be a mix of copper one chloride, miscellaneous salts, and gold. This happens when you have dissolved copper two chloride mixed with your dissolved gold solution and add too much SMB as mentioned above. The problem of CuCl mixed with gold powder is very easy to fix.
> 
> 1) Filter out the solids.
> 2) Flush the solids with lots of hot water.
> ...


First of all, I want to thank all of you that have helped me out and have given me guidance. It was worth its weight in gold.

Steve, you're the man. WOW. I was feeling so down when I thought I screwed up my stuff, but when you said, 


lazersteve said:


> The problem of CuCl mixed with gold powder is very easy to fix.


that there, gave me all the hope I was needing, and I'm thankful for it too.

I managed to follow your steps, along with the post here by kadriver in the thread: *Recovering Black Powder from the Cell*
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=52&t=7093&start=80

and have completed my tasks. 

Yes, I have officially refined and have recovered gold from escrap. I will make a thread with the pictures of the gold button I've made, all thanks to this forum. I was too determined to let my hard work go to waste, and I wasn't going to give up either. I've been reading, studying, reading and studying like there was no tomorrow. I've gained so much information and knowledge from all of this, and more as I completed each step. Now I understand more than just last week.

There are also a few concerns that I have.....

*1.* When I thought I botched my gold, Butcher said that (I think, the last resort) to place a piece of copper in the solution and it may/should collect the gold. I've done that first, before reading Lazersteve's post. Now, the copper has black on it, and has what looks like mildew on it. Below is the photo.




My question is, is there any gold on it? or should I scrape the copper pipe and process the scraping with the acid?

*2.* Because I thought, again, I was adding too much SMB to the solution, I kept testing it with the stannous and it keeps on testing positive. I added SMB, tested, added SMB, tested, on and on, yet it still tests positive for gold. So, to not mess this up, I simply filtered the solution and recovered the solids, and rinsed the filter till it turned from yellow to white.

My question is, since I've already recovered gold so far and separated it, should I add more SMB to the golden yellow solution that's left to see if more gold will drop? and should I heat it a bit if it's below 50F outside?

*3.* When I added SMB the first time I thought I messed up my solution, I'm sure gold did drop. Now, when I redid everything as Steve suggested, and reading the other thread I mention above, it appears that after I made the aqua regia and then added the 10 drops of sulfuric acid to the solution, more gold, or something dropped out. I also have pictures of the dropped substance, and comparing it side-by-side with my washed and dried gold powders, they appear to look alike, in color and texture. Picture below.




My question is, should I dissolve that powder and see what happens? or should I melt it and see what happens? and should I scrape the copper pipe and put it with the substance?

Once again, thanks for all the help and guidance. It really helped, and especially when I needed it. The weather has not been good here at all and it's gong to stay in the 40's this week and rain/snow is in the forecast. I simply couldn't do much outside these last few days to almost a week. 

I'm still gazing at this gold button. It's very shiny too. :lol: I'll put that picture in the Gallery.


Kevin


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## butcher (Feb 13, 2013)

Normally if cementing using a copper metal to replace values from an acid solution, it is best to use a clean flat thick piece of copper.

With pipe some gold may plate inside.
Pipe can be used but I would use a large diameter cut it long wise and flatten it out.

A thin copper can dissolve to the point where pieces of copper fall off into cemented values, copper pipe will also do this after it dissolves enough to get really thin, thick copper buss bars from old electrical panels work well.

At the end of cementing I would take an old tooth brush and clean off copper buss bar brushing powder into solution, re-hang bar to see if more values cement onto copper, clean buss bar again with brush rinse off with spray from a water bottle dry and store in a plastic bag for next time it is needed.

The black cemented out on the pipe or the cement is your values that were in solution.

Here you let the copper pipe dry, (which will also form some copper carbonates and oxides) I probably would not worry at this point about getting the little bit of value off the pipe at this point, (although you can by putting it back into an acidic solution and brushing it off as described above), I would just put it in a plastic bag and used it next time I needed it, getting the values from it then.


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## Anonymous (Feb 13, 2013)

butcher said:


> Normally if cementing using a copper metal to replace values from an acid solution, it is best to use a clean flat thick piece of copper.
> 
> With pipe some gold may plate inside.
> Pipe can be used but I would use a large diameter cut it long wise and flatten it out.
> ...


Thanks for the advise *Butcher*.

I'll put it in a bag for later usage. It was a brand new piece of pipe (3 ft) I cut to that size (approximately 6" long). I normally cut my pipe open and flatten it out, but my saw have been not so nice when I started cutting down the length of the pipe. I need a sturdy place to clamp my vise to hold it steady.

After I use more SMB on the solution I have left and once it tests negative, I'll reprocess that powder that I believe is gold. And speaking of that, the copper pipe is still the same length, with no signs of it being dissolved anywhere that was in the solution.

Thanks again for all your help.

Kevin


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## lazersteve (Feb 13, 2013)

Kevin,

Here are some additional notes on using SMB and testing the resulting solution.

SMB Details

Great job on the clean up by the way!

Steve


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## Anonymous (Feb 13, 2013)

lazersteve said:


> Kevin,
> 
> Here are some additional notes on using SMB and testing the resulting solution.
> 
> ...


Thanks Steve. That link also answered some of the questions I had. I'm glad you posted that link. I can see where some things may have gone wrong the first time. For 1), temp here has not even been near room temp for quite some time (weeks maybe).

I bookmarked that thread too.



Kevin


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## Anonymous (Feb 16, 2013)

I haven't worked with the powder I think may be gold, but I did add some more SMB to the solution I have and it did drop more gold. I can see it on the bottom of the beaker. Not big chunks like the first drop, but at least I can see a bunch of fine brown powder in there. I'll post an update once I finish that off and reprocess the other powder that I have.

I'll be glad when the weather starts getting warm here. It's bright and sunny as heck, but, it's probably around 30-something degrees outside right now.

Kevin


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