Trouble reading posts - Chemistry is all mixed up -

[snoman701]

So let me begin with the statement that I'm not new to chemistry. I have the equivalent of a chemistry minor, then worked as a lab tech for quite a few years. I understand that real world chemistry is quite different from that in the classroom...but with that, I'm confused as hell reading this. I'd be better off with polymer or biochemistry, since most acid base reactions are first year chemistry anyway....and that was getting close to 20 years ago.

Are there any resources that will list the actual chemistry fundamentals, not just "poured a mixture of water and acid over it".

Some of you are clearly very skilled and knowledgeable....but I have trouble following a lot of the posts. Doesn't anybody do the stoichiometry? I never see mention of what measured yield is vs expected....and this is an area where that should be very very important!

Just curious if anyone has any suggestions.

 

[Lou]

Reactions vary rarely run per according to stoichiometry due to competing side reactions so modeling systems precisely is difficult from first principles and often requires some empirical work.

In short, the math only matters when it matters.

 

[Palladium]

Numbers! :mrgreen:
I refine flying by the seat of my pants. I use the basic formulas to get me in the ball park and then it's all experience from there. The only numbers in the end that i really keep up with is the gold that comes out the beaker.

 

[anachronism]

In short, the math only matters when it matters.

Lou nailed it. There are so many variables including amongst many others, the effects of impurities (and different types of impurities) that a "one size fits all" approach is impossible.

Palladium has the measure of the practical application, namely you KNOW the chemistry however the variables mean that your experience shows you quantities required for any given recovery.

 

[upcyclist]

To further elaborate, we also strive to minimize our use of acids to only that which is necessary, for both economic and environmental reasons. Because we can't predict all the side reactions, or even the exact composition of our source material, in practice we start with about half of what we expect to need, then add incrementally.

For example, using too much nitric acid adds several problems: it adds direct costs to your operation (even in a learning-only situation), it creates more acid waste to neutralize at the end of the day, and it can inhibit follow-on reactions because excess nitric is consumed first. When precipitating gold, for instance, excess nitric consumes your precipitant before it can even get to the gold and drop it out of solution. So, if I think I need about 100mL of nitric for a given batch of gold I'm dissolving with aqua regia, I add my HCl base (it's much cheaper, but still don't need a liter for this batch), then I add 50mL of nitric. Once that add has fully reacted, I add more & watch for the reaction to settle, lather, rinse repeat.

Sometimes we know to a reasonable degree the composition of our material, like a lot of 14K gold. But even then we don't know the exact makeup of the remaining 42%. Copper? Silver? Zinc? Palladium? Often, we don't know much at all about it--is the metal (much less the other crap) in my polishing sweeps mostly 14K gold? 18K? 950 Platinum? Sterling? All of the above?

So, yeah--stoich only gets you so far

 

[kurtak]

Numbers! :mrgreen:
I refine flying by the seat of my pants. I use the basic formulas to get me in the ball park and then it's all experience from there. The only numbers in the end that i really keep up with is the gold that comes out the beaker.

:lol: :lol: :lol:

I resemble that statement :mrgreen:

Actually - I figure when I first got into this - the "fact" that I got a - Big Fat F - in high school chemistry - was probably a good thing (I was one of those HAADD kids before they had a name for it - so I slept though it &/or sat in the back shooting spit wads & playing cards etc.)

I figure it (the F) was a good thing - because my head was not filled with a bunch of stuff to cloud my head in the leaning of refining - made picking up & learning refining relatively quick & easy because the chemistry involved has all been directly related to refining - & the result is I have also leaned one heck of a lot about chemistry 8)

If my old high school chemistry teach could see me now :shock:

Kurt

 

[Geo]

I can add that even though refining requires chemistry, not all refiners are chemist. Many refiners, myself included, understand the chemicals needed for the reaction but may not understand the chemistry behind the reaction. I have no formal education. I had to drop out of school at the age of 15 to get a job. I was the product of a broken home and lived with a single mother. She never remarried so for a very long time it was just my mother and myself. She worked a minimum wage job to support us and there was years I didn't have new school clothes or school supplies. It's a common story I'm sure. With an eighth grade education, I took whatever work I could find. My one saving grace was my love of reading. I read almost anything I could find. Never really having enough of anything fueled my dreams of treasure. Having a background of scrounging for a living, I learned about scrap metal. I learned early that some scrap metal contained gold. I had a dream of someday learning how to get the gold out of scrap metal. I had different degrees of success until I came across this forum. I feel I have had some success in being able to separate the precious metals from the scrap metal since then. I still do not understand chemistry very well, but, I think I have refining almost under control. So, refining requires chemistry but being a refiner does not require one to be a chemist.

 

[upcyclist]

So, refining requires chemistry but being a refiner does not require one to be a chemist.

+1

People who come with an open mind learn best here (as well as other places, I would hazard to say). The hardest person to teach is the person who thinks they already know everything. We've seen this on the forums more than once.

My favorite ones are the ones who say "But I have a PhD!" and it doesn't come out until later that the PhD is not in chemistry anyway.

 

[Lou]

MS==more of the same, PhD= Piled higher and Deeper.

 

[4metals]

I feel I have had some success in being able to separate the precious metals from the scrap metal since then. I still do not understand chemistry very well, but, I think I have refining almost under control. So, refining requires chemistry but being a refiner does not require one to be a chemist.

A successful refiner knows his material and knows which materials can be mixed and which cannot. That is not learned in a chemistry class, that is learned by doing.

The benefit of being a chemist is the ability to determine from what is going into a reaction, what is going to come out. But in the practical refining world, there is a bit of head scratching involved because one never knows everything about the scrap that goes into a reaction. And with e-waste that is becoming more and more true with every generation of e-scrap.

So be observant and make notes, they will serve you well for a very long time. And keep reading, you're never too old to learn new tricks.

 

[IdahoMole]

I think I understand the point of view from the OP but if the forum was full of "chemist speak" I would have the headache and the learning curve would be steeper than it already is.

 

[snoman701]

The learning curve would be steeper, but more beneficial.

If you understand the fundamentals, you can troubleshoot so much more effectively. More than that though, it's the only way one can expect to purposely develop newer more efficient or cleaner processes.

So if anyone has any suggestions on texts or manuals, I'm all ears.

 

[butcher]

Hoke's book actually teaches much of the chemistry in layman's terms recovery and refining, Aside from that most of the chemistry is basically organic chemistry. When I learn or see something or see a reaction mixing a liquid and a powder and see fire, and telling me it is a chemical reaction and a few details about it (only sparks more of my curiosity), I am not satisfied just seeing it and knowing what it is, I want to know more about it (many times every detail I can learn about it). If I see something working I want to tear it apart and see or learn what makes it work. I have learned quite a bit about chemistry from asking the question why does it work that way, what is it... then I look for the answer, I find that answer and several more questions pop up in my research, giving me many more questions to find the answers.

Understanding the chemistry helps in many ways, I find many uses for byproducts of reactions that without the understanding of the reaction may be considered waste.
A good refiner will understand the basic chemistry, he may not be able to write the formula for the reaction or even understand it if he saw it written on paper, or tell you what is going on or what else may be formed in the reaction, but he understands enough of the chemical reactions to recover and refine gold doing the chemistry...

Then we can have a chemist which can balance the formula explain all of the reactions but when it come to refining he would not have a clue what to do if something did not react in a certain way...

I have found the forum, my own inquisitive nature and my love of research to find the answers to my questions, to be a great tool for learning chemistry along with learning to recover and refine.

 

[bemate]

The learning curve would be steeper, but more beneficial.

If you understand the fundamentals, you can troubleshoot so much more effectively. More than that though, it's the only way one can expect to purposely develop newer more efficient or cleaner processes.

So if anyone has any suggestions on texts or manuals, I'm all ears.

I'm a chemist myself, and I see your point totally. The problem is that you're not facing a simple set of reaction equations, it's more like 20 happening alongside each other, with some catalyzing each other while inhibiting others and vice versa. The core of the chemistry boils down to which chemicals will react and which will not. That gives you a set of basic tools to explore, learn and improve both the reaction parameters and the yield.

In a way, it's quite similar to what we call natural samples in microbiology; it's a complete mess when you take a bit of soil and dilute in water. You have thousands of different types of bacteria, fungi and viruses competing for the same resources mixed together. Getting a specific type for further work is a mixture of using selective media, specific inhibitors and incubation parameters to favor the one you want. There is no quick fix to use tweezers to pluck out the one you want and isolate it, at least not yet.

I feel this is the situation here as well, the natural samples the gold comes from are so mixed it's just not possible to optimize simply because the next batch you process is different, rendering your optimization obsolete.

But, that does not mean you shouldn't try, most of the relevant reaction equations are here, it's 'only' a matter of balancing then, calculating the composition of your samples and calculating your reaction. Looking at total time spent, I still think you'll be ahead with just adding an excess of acid and doing the waste treatment after. You will, however, have saved some money on chemicals at least.

 

[Geo]

I am not trying to be simplistic about it but while you are trying to fineness a balanced equation, I have already been to market and deposited my check. There are certain things that needs quantitative analysis such as assaying or developing a process or tweaking an existing process, but for the more mundane, day to day processes that are so repetitive that you can do it in the dark, minute fractions falls by the wayside. The only time I have ever truly seen the need for exact measurements is to win an argument. It is even recommended here that you use aqua regia by adding incrementally. There are only a few things that are dangerous by adding too much and I experienced one of them myself. If you are giving a warning that involves exact amounts, then by all means, carry on. If it's it's because a formula only works with exact amounts, sure, that's what it takes. If it's just to say "see, I know more than you", I will be far from impressed.

 

[kurtak]

So if anyone has any suggestions on texts or manuals, I'm all ears.

You can start by reading Hokes book - you will find it as a "free" down load in a number of places here on the forum (start using the search function of the forum) the quickest place you will find it is in FrugalRefiner signature line at the bottom of ALL of his posts

Also most any book on fire assay - I got mine here :arrow: http://www.actionmining.com/ --- & they have a number of other good books related to refining

Outside of that all I can say is you just need to spend more time searching the forum - there are "LOTS" of posting that get right down to the actual chemistry involved here --- YOU just have to spend YOUR time doing the research --- as have ALL of us that are "active" members --- research - is YOUR responsibility

Wikipedia is also very good source of info

Bottom line --- this field is sooooo VAST that you are NOT going to find all the answers to all your question in any ONE book &/or manual --- it takes "research" LOTS of research

I have been at this for six years & have MANY "thousands" of hours of "my own" research into it --- & I am STILL learning --- the ONLY reason I am able to be the active member here that I am --- is because of the MANY thousands of hour of research that - I - have put into it :!: :!: :!:

Outside of that (LOTS of research) you are "not" going to find - A - quick one manual covers/explains it ALL

Kurt

 

[anachronism]

I second the remarks Kurt has made. It's taken me 5 years and a LOT of hours work and research and a great deal of help from other members to get the working knowledge I now have. That knowledge is still tiny compared to some on here.

Learn the basics, nail the base line procedures and you'll be on the right path. Kurt and I are both very hands on refiners learning at the "coal face" if you would. There are a lot of great chemists out there who know diddly squat about practical refining, (and no I don't mean anyone on here I mean out there in the real world) so I would prepare to get your hands dirty and see it all first hand because that's the best learning method.

You can't get good results by merely reading from a book.

 

[upcyclist]

The core of the chemistry boils down to which chemicals will react and which will not.

And remember, don't say "boil" if you just mean "heat" or "evaporate" :lol:

Sorry, I just couldn't resist. For anyone new, that's a joke.

 

[4metals]

Another aspect of the discussion is the availability of chemicals for a refiner working from home as a hobby or a small business. If it wasn't for the hobbyist fraction of this forum, we would go to the textbooks to get the name of the chemicals required and then call up a chemical supplier to get what you need. I learned on the industrial side of refining so getting chemicals was never an issue, but thanks to this forum, it is possible to find sources which we wouldn't normally consider for our chemicals.

Last week I was at a refiner and he had no niter, potassium nitrate, an oxidizer for a flux mixture we were working with. Well thanks to what I have learned from this forum, I stopped in at a Home Depot and picked up some Stump Out and an unnecessary rush to get the right chemicals was averted. You won't find a reference to stump out in a chemistry text!

There are suggestions for homemade nitric acid, an alternate source for tin for stannous chloride, a source for sulfamic acid, metabisulfite, ferrous sulfate, and the list goes on. None of them found in the chemistry textbooks.

Actually someone should start a thread to put all of the unique sources of the chemicals we use in one thread and I can put it in the library.

 

[FrugalRefiner]

Well, this is an oldie but a goodie Chemical Common Substitute Source Matrix. It would be a great project if one of our members could compile all the best information from that thread into a single post. :idea:

Dave