# Does nitric acid damage gold



## erol (Apr 16, 2021)

Hello, masters
If we wash the precipitate we receive from AR solution with copper plate cementing method with concierge or diluent, cold or heat-assisted nitric acid, it will cause damage to the gold dust m
:G 
Great to take advantage of your beautiful information, thanks in advance


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## Martijn (Apr 16, 2021)

Hi Erol, good you translated your post. You'll get better at English as you read and post. Some parts i don't understand what you mean. 

But from what i understand:
To wash your precipitated gold powder with nitric, make sure you rinse a lot with hot distilled water to get all HCL out before you treat it with nitric. 
Other wise you will redissolve some gold. 

You can also follow these washing steps to get really nice pure gold:
https://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=325
That process does not use nitric. 

Martijn.


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## erol (Apr 17, 2021)

Thank you for the answer

But here's what I'm trying to figure out. The precipitate I'm talking about is a mixed precipitate cleared of acids

It could have gold copper iron in it. If I clean this sediment with nitric acid, will nitric acid damage the gold dust


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## Martijn (Apr 24, 2021)

If all traces of hydrochloric acid are out, no.


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## nickvc (Apr 25, 2021)

If you have a mix with small percentages of copper and iron nitric is not needed just use hot HCl to dissolve them after washing your precipitate well, it can and will dissolve some, a very little gold so use it in your next dissolution of dirty scrap.


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## Bakhtiarhasan (Mar 26, 2022)

it will affect if hcl present in dust.


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## goldshark (Mar 27, 2022)

One of my first experiments with trying to clean some small nuggety placer Gold went like this. First, use warm HCL only, diluted with distilled water by 25%. Let soak for 48 hours. Decant and wash 3 times with distilled water. Dry, repeat this time with 67% nitric cut 25% with distilled. Gold immediately started to dissolve with whatever else was alloyed with it. My questions are: 1. Did the HCL erode micro holes into the nuggets, leaving behind a certain amount of HCL to react with the nitric? 2. Should I use a carbonate wash in between HCL and Nitric?


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## nickvc (Mar 27, 2022)

To fully remove the acid you need to incinerate your material.


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## orvi (Mar 27, 2022)

nickvc said:


> To fully remove the acid you need to incinerate your material.


Yes, espetially from dropped gold. HCl boiling after precipitation always remove some small ammount of gold.


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## nickvc (Mar 27, 2022)

orvi said:


> Yes, espetially from dropped gold. HCl boiling after precipitation always remove some small ammount of gold.


Even if you do incinerate your precipitate you will still lose a little hold to the HCl especially if you boil it but it is minimal and to recover add it to your next dissolution.


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## kurtak (Mar 27, 2022)

nickvc said:


> Even if you do incinerate your precipitate you will still lose a little hold to the HCl especially if you boil it but it is minimal and *to recover add it to your next dissolution*.


Per the bold print - or - cement it out

All of my gold washes go to a stock pot - for two reasons

1) - for settling --- when decanting your washes (both water & HCl) you will always have "some" very small gold particles that go off with the pour - though you will see some (just a few) of those particles go off with the pour some of them are actually small enough that you can't see them (at around 40 microns the human eye can not see a individual particle) particles that size "take time" to settle --- you will be surprised at how much gold settles after a week or two - gold you don't see when decanting the washes --- GSP is the one that first made me aware of this

2) cementing the washes with copper will produce more "ultrafine" particles from the "minute" amount of gold dissolved in the washing process --- again - these particles are "ultrafine" & take "time" to settle - again - GSP is the one that first made me aware of this (this is done right after washing) --- edit to add; - these particles may well be small enough & few enough that you don't see them - but they will settle given enough time

So - this is what I do with my washes --- I first pour the washes into a container that I figure is big enough to hold the washes but also small enough to hang copper in & run the cementing process (hang copper plus air bubbler) then at the end of cementing (end of day) I will pour that off into a larger container for settling of both the particles that came off during decanting as well as particle from cementing

When the larger settling container is full from doing the above I will give that 2 - 3 weeks for settling before siphoning off (most) of the water/acid then start refilling the settling container as above

If you are washing gold on a regular basis & if you follow the above procedure - will be surprised at how much gold you will recover at the end of a year

To put it in perspective - when I was at my peak in refining (& before I retired back down to hobby level) I had as many as 4 - 6 settling buckets (5 gallon) going so that each bucket had its 2 - 3 weeks settling time

By the end of the year I would have *plus*/minus an ozt of gold just from my gold washes

Currently - having gone back to the hobby level & only doing 4 - 6 smaller batches a year (last three years) I have about (plus/*minus*) a gram of ultrafine gold in the bottom of my settling container - which is a 1/2 gallon (2 liter) jar

Its enough now that I can decide to dissolve it with my next small batch - or - just add to it some more from the batches I intend to run this summer

Kurt


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## goldshark (Mar 28, 2022)

I appreciate the fact that most on here are refiners. I not only refine, but also collect certain nuggety gold. The nuggety gold I would only like to enhance the appearance and clean. For 1- 2 gram pieces, I can generally get 1.2 x spot, based on the assay, so can generally sell for 20% over spot. More for larger nuggets and crystalline specimens. I still put my waste in a stock pot.


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