ph levels.

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Mountain Man

Well-known member
Joined
Sep 11, 2016
Messages
102
Fellow gold producers.

I have a situation that I am at a loss over and know with the vast knowledge that abides on this forum you will have the answer to my dilemma.

I have 3 jars of solution from A.R. recovery method. All three have been neutralized with urea and treated with sodium metabusulfite. I tested for gold before add the precipitant and all 3 show black and purple and not faintly but prominent.

The problem is the gold won't drop. So I tested again with s.chloride and again it shows heavy gold content in all 3 batches but still cannot get it to drop.

My theory is that the ph level is off but I have no way of testing that as of now.

Can I impose on your vast wealth of knowledge once again to guide in the right direction.

Thank you in advance.
 
If you added way too much nitric, urea will not eliminate it. How much of each acid did you use to dissolve how much material? Was it all gold, or a mix of metals?

Dave
 
Hi Dave,

Thank you for responding to my request for help. To answer your question I use a nitric acid substitute that consists of 8 oz. of sodium nitrate mixed into 2 cups of hot water and stir until s.n. is dissolved. Then I ad 4 cups of muriatic acid to the mixture of sodium nitrate and about 5 lbs of material to be stripped consisting of gold fingers from memory cards and processor chips, (typically ceramic) and misc. clean computer boards I purchase from overseas. They have gold but no other items on the boards. Likely just factory mis orders or boards that were made wrong. No items ever soldered onto the board so they are very clean. In total I try to run my batches between 4 to 6 lb's depending but that is my usual batch size. Then I let it sit overnight. The next day I pour of the solution pregnant with gold and neutralize with 8 oz of urea mixed into 1 cup of hot Water and ad to the solution.

Kirk
 
Dave,

Now that you say that it makes perfect sense. I think I need to start with less nitric and ad more if required. If the urea won't neutralize it, what do you suggest I do to neutralize it? Would baking soda do it or will it require something else. I was reading some of the other articles on to much nitric and some say to evaporate it with heat although there is a danger of explosion of the nitric acid doing it. Would it do any good to ad more material to strip and try the use it up now that I have added the urea? Judging from the number of bottles I have that have this problem I need to reduce the amount of both the muriatic and nitric acids for the size batches I am processing or increase the material I process in each batch. I like that option better. What are your thoughts.
 
You have two solutions to your problem.
1. Simply add more product to consume the nitric that is still free.
2. Put copper sheet or buzz bars into the solution to cement any gold out, this will need to be refined once harvested.

The advice we give on the forum is to start with an excess of Hcl and add nitric or substitutes in small increments, if the metals stop dissolving add a little more nitric and if after an addition of nitric there is no reaction add more Hcl.
 
Thank You nickvc,

I have a couple of questions,

If I add more material will it still react and dissolve the gold since I used urea or does the urea not neutralize the HCL.?

I do have copper sheets that I could use but I am new to that technique so I am not familiar with how much copper or how to tell how much I need or how much is to much.

Thank You.
 
nickvc,

After I stated I did not know about the amount of copper to use it dawned on me that you said it would cement to gold out and I understand that to mean it will attach itself to the copper and thus the need for refining afterwards. Is that correct or do you mean the copper will dissolve also and will need refining to separate the gold and the copper.

Kirk
 
Mountain Man said:
nickvc,

After I stated I did not know about the amount of copper to use it dawned on me that you said it would cement to gold out and I understand that to mean it will attach itself to the copper and thus the need for refining afterwards. Is that correct or do you mean the copper will dissolve also and will need refining to separate the gold and the copper.

Kirk

The copper will partially dissolve and use up excess Nitric, and when the excess Nitric is gone the gold will precipitate onto the copper as powder.
 
could it be possible that PMs other than gold might be present in solution? i ask only because from what i have learned thus far, tests for PMs in solution turn up positive for metals other than gold as well as other PMs have industrial applications like gold does. i, of course, might be wrong here and if i am, inform me. cant learn from a mistake i made unless i know it was a mistake ane why, after all.
 
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