Treating heavy sands with nitric, unexpected results

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R

Ragnor

Active member
Joined
Mar 14, 2015
Messages
28
I treated a bit of heavy sands concentrates with nitric acid today, just to see what would happen. The reaction started very slowly. At first the solution went yellow and then pretty much ran away after 10 minutes or so. It fumed hard for 15-20min and then slowed enough that I felt comfortable taking a look at it.

The solution had gone a cloudy off white. Then it formed a snotty looking layer on the top. As the reaction slowed down something interesting occurred. Gas bubbles or liquid with the gas? would rise to the surface and burst. As they burst a solid white bead would form and then sink. As it sank it would re-dissolve in solution. It was rather fascinating to watch. rising and solidifying and then sinking and dissolving.
Can anyone tell me what I was observing there?

After a time the reaction pretty much came to a halt. I could see silver metalic solids on the bottom mixed with white and pink material. I would stir it occasionally and more gas would evolve.
When this stopped I added a bit more nitric.

More brown gas evolved for a while and then the solution begin to turn green. I assume this is iron dissolving?

I then got a light green /yellow solution which turned to a darker green over the next several hours.

I am just wondering if anyone can explain to me what I was seeing in accordance with my account Ive written here?

I now have a cloudy moss green solution which I am unsure what to do with. I expect I will decant and or filter it in the morning to try and get some idea what the stuff was made out of.
 
I just remembered that I actually did video part of the reaction. Once I looked at the video I was able to see much clearer what was happening. Rather than metals solidifying on the surface and sinking. They were actually carried to the surface by gas bubbles and then being dropped.

[youtube]https://youtu.be/4MGURPRdtuk[/youtube]

Hopefully that helps some to show what I was trying to explain
 
You say unexpected results, what results were you expecting?

I dont know jack about ore first hand, but, I will see if I can help you.

Did you dilute the nitric at all? Use it straight? What concentration is it?

Judging a reaction by color alone will only lead you to endless issues.
Stannous chloride is a definitive test if used properly, make some, get acquainted with it, and use it on a small sample of your green solution to see if any precious metals are in solution. Platinum group metals can sometimes go into a nitric solution.

Beyond stannous, you will also need a small test solution of dimethylglyoxime, prepared in water (with a little NaOH if needed, NOT alcohol. It takes forever and a day to dissolve, patience is key in all things refining). When testing a small sample of your green solution with it, this will create a voluminous yellow precipitate indicating palladium, assuming some is in solution.

There are a couple other things you need, that will get you well on your way. CM Hoke's books(plural), available for free download here via frugalrefiner, will get you the basic knowledge you need. After that, since she does not deal on ore, probably reading "the Metallurgy of Gold, by TK Rose" will help you as well. He goes over ore a good bit in his book. Beyond that, any other ore specialty books, I don't have, or know about. I'm not fortunate enough to live in a gold bearing land, so my metal comes from recycling.

Don't skip reading Hoke though, yes, one is for refining waste, and the other for testing, but she wrote those books for any regular Joe to learn from, no phd in chemistry required. With those under your belt, grasping what Rose said in his book will come easier.

Forget youtube, it will kill you... Save maybe a couple dozen videos by a few select members here. Palladium (aquilla refining), kadriver (sreetips), Geo (same, Geo on youtube) ... These guys have put a great deal of time and effort into their videos, to be done as good as possible to share all the pertinent facts, not just the key highlights to get a bazillion views.

There is a thread here that goes over testing for any and every metal in ore you can think of, after the books, read through it.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=44&t=10932

Good luck to you! I know it can seem like a lot to take in, but, trust me when I say that it is best to take it slow, steady, and to be as sure as possible first. There are many dangerous reactions that can cause you serious harm.
 
Thank you for the responce.

The "unexpected" part was seeing the material rise and fall seamingly as a gas and a precipitate. I thought I was seeing a rapidly reversing redox reaction. I may have been, but the video looks more like it was just a mechanical transport. I happen to be looking for a rapid phase shifting redox reaction. So I saw this and... yeah , anyway. video says probably not.

Beyond that.

Yes I grabbed a handfull of similar looking materials and tossed them into a beaker. To my shame I will even admit in my haste I forgot to even weigh them. Ive been waiting close to 20 years to dissolve this stuff and I got in a hurry.
I definitely tried to do too much at once. Probably 10 grams of silver material in one beaker and 50 grams of oxidized copper/silver/??? material in the other. Besides this material I posted about here which was just lying in my gold pan.

I also got in too much of a hurry trying to push the reaction faster and this resulted in my excess of nitric acid.

I do appreciate your instruction, advice and critisism.

I will certainly be doing allot more reading on this forum and the books that have been suggested.I did a bit of browsing last night after my posts and I see that likely any question I could ever ask has already been answered on this forum.

My lifelong tendency has been to just charge into things and see what happens. And while this has resulted in my gaining of much more knowledge than my peers and first hand experience.
It has also resulted in more injuries and more 'getting in trouble' Than most of my peers also.I can see that the 'hold my beer' approach to chemistry is not going to be as productive as methodical and calculated procedures. I'll have to work on that.

A thing I would share, this is just for the sake of the matter.
weather I was born this way or as a result of the many head injuries I sustained growing up. (It's hard to say at this point). But when it comes to learning. If I read something I can understand it. But after 10 minutes or 15 minutes the page just kind of becomes a blur and nothing makes sense anymore.
But I can watch a video lectures on physics 802 all day long and I follow right along and absorb the information.
So reading has always been tough on me. that is why I embrace the youtube videos so much.I guess that means I'm a visual learner?
I suppose for the sake of science I will have to discipline myself and do some real reading. I know I will be better off for it.

Once again, Thank you. I do appreciate it.
 
Correct, the floating material was not self reducing, but just bits that were being dissolved, carried up by the bubbles of NOx gas formed by the acids work.

Even goldfilled jewelry can have this happen, or silver being cemented with copper, in a solution containing excess nitric.

That thread I posted a link to, has virtually any and everything you could think of for quick testing and confirmation of matetial, but, an assay is something that you should really (really) look into getting.
Some elements can be a bit of a nuisance, some can be life threatening. It's far better to know, so you can be prepared for any troubles that inevitably come.

An assay will cost a little money and a little time, but, after 20 years, what's a few more weeks? In that time you can have a much better foundation of knowledge. I'm not trying to preach, or stand up on my soapbox, just trying to help you get over the learning curve and keep you from making the same mistakes that I, and numerous others have encountered by initially going to the 'school of youtube'.

Indeed, this forum is a great place to learn. It has been around for over 10 years now, and literally everything you could imagine has been covered. It is single handedly, by far, par none when it comes to the amount of wisdom and experience offered. This place has it all.
 
Ragnor said:
A thing I would share, this is just for the sake of the matter.
weather I was born this way or as a result of the many head injuries I sustained growing up. (It's hard to say at this point). But when it comes to learning. If I read something I can understand it. But after 10 minutes or 15 minutes the page just kind of becomes a blur and nothing makes sense anymore.
But I can watch a video lectures on physics 802 all day long and I follow right along and absorb the information.
So reading has always been tough on me. that is why I embrace the youtube videos so much.I guess that means I'm a visual learner?
Click to expand...
If it helps, you're just like everyone else. Edgar Dale summarized the situation as:

People retain
•10 percent of what they READ
•20 percent of what they HEAR
•30 percent of what they SEE
•50 percent of what they SEE and HEAR
•70 percent of what they SAY and WRITE
•90 percent of what they DO.

While there is research that will disagree with the numbers, and even the underlying theory, we all retain information better by seeing, discussing, and doing.

Dave
 
I enjoy YouTube and watch quite a lot of the videos. The catch is how to tell which video has honest and useful information in them. I post most of my videos there as well, and know that there is a chance someone will randomly stop by and feel they can do it as well or better than me. While none of my videos are meant to be a "how to", there is always someone that thinks that is what they are, and that they are meant to be "directions" on how to do things. When I search videos on YouTube I seldom end up watching the video for what it is described to be as much to see if I can pick up some small, useful piece from it. For example I may watch a refining video showing the use of AR and the thing that stands out to me will be how the filtering was done, or maybe what item was used for the heat source. YouTube can be a useful source of information, but having a good basic understanding of the subject is needed to keep from making a real mess and not having the knowledge to find your own way out of it when using it as "directions" how to do things.

I feel that I learn better from a visual standpoint as well. Getting older I now have eye problems that make reading paper books harder for me, but I find I can read things on my computer screen easier now than just a few years ago. So now I have pick up new ways to learn as well as try to learn the subject I am studying.

I can some what relate to having the material for a long time and wanting to process it. In the late 1990's I found a 30 gallon tote box of ceramic CPU's while working a job. I kept them for 5 years and never found a way to recover that gold before finally throwing them in the trash.
(if I only knew then what I know now :shock:) I decided then that I would never do that again. I found the how to on this forum just a few years ago, and it will never happen again.
 
Concerning the green solution. I decanted it from the solids and then left it sitting for a couple days while I obtained some tin fishing weights and made a batch of stannous chloride.

Two things to do with that:

After sitting for 2 days the green solution has turned a golden brown. It was exposed to air and sunlight.

The solution made from gold panning concentrates and nitric acid tests positive for platinum. I get a bright yellow orange reaction with the stannous solution.

I'm a little confused by this since platinum is supposed to be immune to nitric acid attack. I am guessing this likely has to do with arsenic or sulfur in the mix?

At any rate. I guess I want to rewash the now dry solids with nitric and then see what dissolves in aqua regia?

Looks like I am going to have to get to work on my assay furnace also. I have buckets of the stuff.....
 
If you suspect arsenic even in the least, and you do not know exactly what you are doing, you should not be treating it with acid. Look up posts by Irons associated with arsenic and you will see what I mean.
One breath nearly killed him, and he was several months if not longer and many thousands of dollars spent on recovering.
Also if you roast the stuff, don't breath any fumes.
 
I recently read a report on 3 men who died in a an ore refinery in the late 1800's when hydrochloric acid was first being used to treat arsenopyrite and the necessity of adding nitric acid to that solution to avoid evolution of deadly gasses.
I learned the hard way about roasting it for myself many years ago.

Unfortunately arsenopyrite is at least 50% of the ore materials in the area I do most of my work. I had the white bands on my fingernails at the end of last summer just from getting small amounts of water in my mouth daily while dredging.

I should probably study up on the matter more, but I do understand the significant risk and or danger.
 
Ragnor said:
I treated a bit of heavy sands concentrates with nitric acid today, just to see what would happen. ....

.......More brown gas evolved for a while
Click to expand...


I can tell you exactly what happened.

You took an unknown substance, added a strong acid to it and made a toxic, deadly gas evolve from it.

Stop. Just stop.

Get an assay. You don't what you have or how or even IF you can recover anything of value from it.

And you won't know until you get an assay.


Not trying to sound like I'm preaching, but decades of working with and around various corrosives has taught me that taking and unknown material and adding in some acid "just to see what would happen" is a sure fire disaster just waiting for a victim.

Just get a assay already so you will know what you have and how to work with it.
 
Get an assay, get an assay.... You know how many times I have heard that in the past 20+ years? Doesn't anyone do anything for themselves anymore?

I personally do not have a giant pile of money laying here to have every heavy rock I find assayed. At $250 a piece for assays a person better darned well know what they are sending off before they start paying for assays.
The reason there is still undiscovered ore bodies laying around in those mountains is because nobody could recognize what they are seeing and they could not afford an assay even if they suspected that they had something.

I'm trying to make money. Not give it to someone else to do what I am already capable of.

I understand that I am mixing things and evolving deadly gasses. I get that. That is why I do not stand around breathing stuff. I don't live in a city. I'm not confined to a tiny work space. I don't have neighbors to worry about. My life is my own I am responsible for my life. I operate in accordance with my own understanding. "Light fuse and get away" has kept me alive for over 40 years now.

Driving on the freeway and most certainly in a city people are breathing these gasses daily.

So that's my way of thinking on the matter. If yah leave everything to the professionals, pretty soon you end up an ignorant consumer. I myself have no desire to be either.
 
There are some very interesting threads available on the forum about assaying. You can always learn to do it yourself and save the chemicals for when or if they are needed. On this forum good questions get some good answers, so getting guidance in learning to do an assay shouldn't be a big problem. Who knows you might be better off without the chemical treatment, smelting may be a better option depending on exactly what you find in your ore. And maybe with the right questions you can help someone later, before they ask the same questions. There is also the Book and Other Information section that has quite a lot of help in that area as well. Then there is the section called Sampling / Assaying / Testing. There another section called Prospecting, Mining, Ore Concentrates & Geochemical which I am sure can help a lot as well. That is the nice thing around here, there is a lot of information, just search for it.
 

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