PH level test.

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Mountain Man

Well-known member
Joined
Sep 11, 2016
Messages
102
I haven't been on for a while but thanks to all of you who patiently helped me along the path of the golden rainbow. I am finding my pots of gold thanks to all of you.

I once again have need of more knowledge.

I feel that I am leaving some gold behind in the A.R. solution. I test and it shows gold after I treated it with SMB. I realize that is because there is still active nitric in my solution that is still dissolving the gold making it impossible to recover. My method of neutralizing is urea until I see no more bubbles but that is not working as well as I want. I know the ph levels of the solution is the answer but what I do not know is what ph kit do you recommend. I can find them for swimming pools and hot tubs but I do not know it they are the right ones to use or not, so that is question number 1.

1. Which type and make of a ph testing kit do you use and where did you get it.
Question 2 will be the process for the ph kits use.

Thanks again for all the help you have provided me with. Without it I would have given up long ago.

Kirk
 
I'm not 100% sure that it would help you looking at the pH, but . . .

I have a relatively cheap digital pH meter that I'm sure you can buy online that has worked well for me for a long time. I mostly use it when treating waste acid, when done, give it a good rinse in clean water, put the cap on and hang it up. I also have little litmus paper pH indicators, but I now trust the meter so much that I don't bother with the papers anymore.

Any solutions from which I have already precipitated the Gold get left with a Copper bar in for a couple of days before it goes into the waste container, that way, any trace Gold as well as PGMs cement out on the Copper and goes in to a separate "retirement fund" container.
 
This is the one I got locally -> https://www.brewshop.co.nz/waterproof-ph-meter.html

But some friends have bought the really cheap orange ones online and they seem to work just as well.
 
Hi Mountain Man!
I think it may be better to try sulfamic acid.
Sulfamic will actually "use" the nitric to create sulfuric acid, contrary to urea.
Correct me if I'm wrong here guys.
You can of course evaporate or use "massive" amounts of SMB to spend the nitric.
 
Depending on the amount of nitric acid left in solution you may or may not need large amounts of SMB to use up the remaining nitric. When expecting a certain amount of gold, I use a ratio of SMB to make the expected drop, then allow the AR to redissolve it if there is enough nitric to do so. If you use the minimum amount of nitric to get the job done it should only take a time or two to use it up this way. Also using a minimum amount will conserve your chemicals and time as well. When using excess nitric to perform some processes I use heat to get the nitric down first to a manageable level then use the sulfamic to further destroy the nitric, something that urea does not actually do. Often when doing large lots of gold filled the nitric seems almost impossible to destroy with out using heat. My theory is that somehow the sulfuric produced from using large amounts of sulfamic may be reacting with the copper from the gold filled at times to produce more nitric. Maybe one of the more chemistry knowledgeable members can help with that theory.
 
Thanks Shark

If you perform a dissolve and your base material is all dissolved using a hot solution you'll see that you can still have brown gases evolving from that solution. If you continue to keep that solution hot until the gases change colour to white fumes rather than darker fumes you will have destroyed most of your Nitric before you need to begin denoxxing by other means.

If you think about this logically- the "evaporate" method of denoxxing is really only an extension of this. So save yourself some time and chemicals and treat every solution as above.

Jon
 
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