Zinc digestion underway

[SaltwaterServr]

My first test batch of ore digesting right now. It took another tablespoon to get the solution to go clear. It could've been less was needed, but I figured why the hell not.

 

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[kurtak]

SaltwaterServr

I am an "actual" refiner of PMs (Precious Metals) (& I have just "recently" joined this forum) so - I have some questions as well as some concerns I would like to address concerning your video

At the beginning of your video you say that your bucket is a "gold in chloride solution" & then go on to say that it is "HCl (hydrochloric) acid brine with gold"

Based on that description - I "assume" that you had a starting material of gold bearing ore to which you added HCl in order to "leach" the gold out

If HCl is the "only" chemical reagent you used in the attempt to leach the gold from the ore - I can "assure" you that you dissolved zero (absolutely NO) gold

HCL "only" will NOT dissolve gold - no matter how fine the gold is --- it MUST have an oxidizer along with it (HCl plus oxidizer) in order to dissolve the gold thereby creating the desired "gold chloride" solution - from which the gold can then be recovered using zinc

So my first question is did you use "only" HCl to try to dissolve your gold - or - did you add some other reagent (that is an oxidizer) to it as well ?

Also - zinc is not really the metal of choice for recovery of gold from a gold chloride solution - copper is actually the metal of choice for recovering the gold from a gold chloride solution & for good reason

By adding the zinc to the solution for the purpose of precipitating the gold out of solution - is a process we refiners refer to as "cementing" the gold out of solution

The process works because of an "ion exchange" that takes place when a metal that is "more reactive" with the acid is introduced to a solution that has a metal that is "less reactive" already dissolved in it

This is known as the "reactivity series" which starts with the least reactive metals at the bottom & the most reactive metals at the top - so metals are listed such that depending on the metal - other metals are ether above - or - below a particular metal according to where in the series they are listed

Here is a list of the reactivity series --- https://en.wikipedia.org/wiki/Reactivity_series

you will notice that PGMs (Platinum Group Metals) are at the very bottom of the list & that is because PGMs are the "least" reactive to acids - while zinc is why up on the list & that is because it is much more reactive to acids - but there is also a whole host of other metals below zinc which is why zinc is not the preferred choice of metal for cementing your gold from solution

The reason for that is that with zinc being so high on the reactivity series - the zinc will cement (precipitate) not only the gold - but - also any & all other metals below zinc --- the result being a recovered gold that is contaminated with other metals that were also dissolved by the acid

On the other hand - as you can see - copper is much lower on the reactivity series with the only metals listed below it being the PGMs gold silver & mercury - so copper will cement "only" those metals below it - thereby giving you a much cleaner cemented (precipitated) product as a result of the metal "ion exchange" reaction when using the reactive series to recover dissolved metals from solution

Now then - it actually gets a bit more complicated then that - but that is the general idea of using one metal to recover another metal from a solution & we can maybe get more into that if you wish --- but first we need to answer my above question of --- did you use only HCl as your leach - or - did you use HCl plus some sort of oxidizer --- & if so then what was your oxidizer

Kurt

 

[SaltwaterServr]

I ran 7% H2O2 as the oxidizer, but there was a delay between the addition of the HCl brine. I pretty much lost my oxidative potential, just like you mentioned, and didn't get squat.

Without an assay on this ore, and the other major spot I'm working on, I don't know how much copper I have in my ore to begin with. That of course can be an issue from the get go because I might be precipitating gold out of solution while it is still reacting in the pulp stage.

I used zinc this time around because I know of someone who uses it and I wanted to test run his HCl/H2O2 process before moving to CIL.

I'll happily listen to any advice you have on any of this.

 

[kurtak]

I'll happily listen to any advice you have on any of this.

OK - for starters I am not sure where to really begin because I don't really have enough back ground on what you are working with &/or your method(s) of processing - other then you are working with ores & you are trying to leach the values out of the ore(s)

That said - the first thing I am going to say is that although ores can be leached with acids it is not the best choice - cyanide leaching is a "much" better choice - & believe it or not - cyanide is actually safer then acid leaching - PROVED it is done right

I did read your other thread titled "Time for some experimental processing" (this morning) so now see you are working with 35% H2O2 - at that high of a concentration H2O2 is VERY !!!! nasty stuff - if you get even a little bit on you it will cause a chemical burn that is as bad "if not worse" then a sulfuric acid burn - of the 3 common most "dangerous" (meaning there are others) chemicals used for PM recovery/refining in there order of danger are high concentration H2O2, sulfuric, & NaOH - other chemicals (like HCl, nitric, etc) though "hazardous" - do not have the level of danger of H2O2, sulfuric or NaOH (as far as getting it on you)

One of the first questions I have is are you trying to leach the ore as is (in other words - just as it comes out of the mill) or are you leaching concentrates - in other words ore concentrated down by panning or concentrated by running the ore over a Wilfley (shaker) table or wave table

The reason I ask is because you said

I ran 7% H2O2 as the oxidizer, but there was a delay between the addition of the HCl brine. I pretty much lost my oxidative potential

You likely did not "loose" your oxidative potential due to a "delay" of adding the leach to the ore (though that is possible) but rather it is more likely it was lost to being used up by other elements in the ore that are more reactive then the gold - the "less" concentrated the ore is the more likely the oxidizer is going to be used up dissolving the more reactive elements in the ore before it is able to work on dissolving the gold - &/or - if all the more reactive elements are not "completely" dissolved by the leach - they will cement any (small) amount of gold that "may" have gone into solution back out thereby resulting in your solution being barren of gold (there is a way to test your solution to see if it in fact has gold dissolved in it which I will explain later)

This is why "in part" acid leaching is not the best choice for leaching gold from ore(s) --- unless you are able to concentrate it down to a good "heavy" gold bearing concentrate - you are going to use up a HUGE amount of acid &/or oxidizer to dissolve all the more reactive elements before you reach a potential to dissolve & hold in solution the gold --- in other words acid leaching gold from ore is not very effective for leaching ores - unless you are first able to concentrate the ore to a "high" gold bearing concentrate

That is where cyanide is the preferred leach for ore leaching - it is far more selective at targeting the gold (as well as silver & to a small degree copper) & so it does not get used up trying to dissolve the other elements

Also - when it comes to acid leaching of ore - chlorine is a better choice for an oxidizer then H2O2 (even concentrated H2O2) though H2O2 (as an oxidizer) has the potential to dissolve gold - chlorine (in the form of sodium hypochlorite or calcium hypochlorite) has a much better potential - the problem with chlorine leaching is keeping the chlorine in solution long enough for it to do its work - it wants to "gas off" quite rapidly if "conditions" are not properly controlled &/or maintained - as long as condition are controlled & maintained its a better leach then H2O2 (the conditions for chlorine leaching is a whole other discussion)

Now - earlier I mentioned "testing" your (acidic) solution for gold - this is important because without it you are only guessing (that gold is in solution) & the result is you will likely end up chasing your tail wondering "where is my gold"

To do this we make a solution called stannous chloride - it is made by dissolving tin in HCl (I am talking about the real element tin - not so called tin cans which are actually sheet iron) you can get tin as solder, fishing sinkers, & pellet gun pellets - just make sure its tin & not lead - the solder will be like 95% tin 5% antimony but that's ok because the tin will dissolve & leave the antimony as a black precipitate that can be filtered out - sinkers & pellets should be pure tin

after you dissolve the tin with HCl you want to put it in a small bottle like an aspirin bottle or eye dropper bottle to keep from contact with air or it will end up oxidizing in a couple of days & become useless

Stannous chloride is very sensitive at testing acidic solution that have even very small amounts of gold &/or PGMs dissolved in the --- gold will show a purple color to an almost black purple (when there is a lot of gold in solution) palladium will result in an emerald green to a dark forest green & platinum will result in an orange color

You can preform the test different ways - I do it by putting a "drop" of the solution (I want to test) in a plastic picnic spoon & then soak up a bit of the stannous chloride on a Q-tip & then soak the drop of solution up on the Q-tip --- if the solution is positive for gold the Q-tip will turn purple to almost black --- or you can put a drop of stannous on a paper towel & then a drop of the solution on top of that & you will get the same result if the solution is positive for gold - or you can just put a drop of each in the plastic spoon & the solution will change color if its positive - this last method does not work well on a solution that is already dark from base metals that are also in the gold solution - there is no mistaking the results of the test if you use the Q-tip or paper towel method

Kurt

 

[SaltwaterServr]

OK - for starters I am not sure where to really begin because I don't really have enough back ground on what you are working with &/or your method(s) of processing - other then you are working with ores & you are trying to leach the values out of the ore(s)

Kurt

Kurt, to begin with, thank you for the in-depth response. It is greatly appreciated.

What I'm working on, with Mad Machinist as well, is a way to scale down what the major, and minor, gold companies do at the industrial level to where an advanced amateur miner can do this in their own backyard.

In essence I want to devise a simple system where a person with a $1500 flail/impact crusher can crush his refractory ore, put in an acidic water bath, wait a month and let biox do its thing. Or, if they're willing to undertake the chemistry, let them do what I'm working on to move forward with chemicals they can get off the shelf at a Lowes/Home Depot/Menards and online at Amazon.

That's one of the reasons I'm not working with cyanide at this point, plus the permits, and thirdly I'm doing this work in a residential neighborhood. Cyanide is dang cheaper and easier as long as you're not working with preg-robbing ores with high organic content, which is why there's not anyone using HCl as a leach since, well, cyanidation was discovered. In my case, and a lot of us smaller miners, HCl is a 30 minute trip to the store.

In reality, I'm doing two different things. I'm putting together a system for the weekend prospector who wants to work refractory lodes. The second is that I'm working up to start my own pilot plant.

There's a surfing movie in the late80's or early 90's where a surfer from Arizona of all places goes to Hawaii and gets his art supplies stolen. He's broke, his board breaks his first time out, and he's out of luck. He runs into a local guy who agrees to teach him the ropes of real surfing. They start out riding this monster wooden board that's like 14' long before progressing up to the modern 3 fin hand formed foam board. I know nothing of surfing, just a good comparison.

In my venture here, I'm learning the basics as I move up. I'm running straight out of a flail mill, screened down to 100 mesh minus, oxidizing with HCl leach. Old school stuff. No upgrading, no froth floatation, no grinding circuit to take me down to where I want to be at 75% sub 75 micron. But that's where I'm headed. Jaw crusher to 1/4" minus, ball mill, floatation circuit, and then if I have a business running at that point, cyanide with CIL or CIP followed by elution to extract the gold.

Your method for making a simple stannous chloride is really appreciated. I've already made a note of it into my files.

As far as moving forward, I know where two froth cells are sitting in the desert abandoned. I cannot for the life of me remember what kind of condition they are in. If not, I've contacted a dealer (owner of 911Metallurgist) to get some cells from him. I still will probably pick a pair of cells up from him to start so I'm reducing down the amount of solids I'm processing, well, you know the ratios possible from upgrading.

My minor in college was in chemistry, albeit organic polymer chemistry. This is all inorganic. You want me to make you Kevlar? I can do that all day. Simple as all get out. You want me to pull gold out of arsenopyrite...well I'm still learning as I go. That's kind of why I'm comfortable with using lots of particularly nasty chemicals. Phosgene and me go way back in polymer catalyzation.

I will say that "The Chemistry of Gold Extraction" has been a fantastic resource. So has this site and 911 Metallurgist. I expect trial and error, and learning along the way.

What I can say so far is that I need a good ORP meter. That would've eliminated some of the speculation on the redox potential when I went to add the HCl to the H2O2 slurry. The delay in my case was over 24 hours, possibly 48.

NaClO to generate chloride ions for oxidation is a step that's coming down the road for me, but I'll need to get a pressure vessel set up and then it needs to be run at an elevated temp if memory serves.

Then again, I might just bite the bullet and go with Biox using the bugs you can buy online at ATCC.org. Once I get a better feel on what my ore will be like, set that up and acclimate the little buggers to it in a nice sulfur rich low pH environment and get it a rolling.

 

[kurtak]

SaltwaterServr

Thank you for the reply further explaining your back ground & project(s) you are working on

My minor in college was in chemistry, albeit organic polymer chemistry. This is all inorganic. ............ You want me to pull gold out of arsenopyrite...well I'm still learning as I go.

Good to hear that you have a back ground in chemistry as that certainly gives you a clear understanding of the dangers of working with dangerous chems like concentrated H2O2 - you wouldn't believe how many people I have seen jump into this with absolutely NO knowledge what so ever but because they watched a couple youtube videos they think they know it all & no matter what you try to tell them they just wont listen until they have hurt them selves

An example of this is I recently received a batch of about 11 pounds of gold plated stainless steel from a guy to process - he originally had something like 150 pounds of this material (it was running 4.5 - 5 grams recovery per pound) so I asked him if he already processed 140 lbs why he just didn't finish the last 11 lbs - his reply - "because EVERYTHING in my garage AND house is now corroded & I have had to go to the hospital emergency twice - once to have my eyes flushed out (almost went blind) & once for breathing problems from breathing fumes

Safety is my number one concern when discussing this - which is why I made mention of it --- so knowing you have a back ground in chemistry is good to know

But you are also right - organic chemistry - & the chemistry involved in recovery &/or refining of PMs (Precious Metals) are two very different ball games

Now for a little back ground about myself --- until about 7 years ago I had absolutely NO back ground in chemistry - in fact in high school I got a Big Fat "F" in chemistry

25 - 30 years ago when I was living in Northern California I had some involvement in both placer mining & hard rock mining - I posted some about that here http://www.treasurenet.com/forums/g...rest-service-evicts-families-razes-homes.html (my post is on the second page)

So I already had an interest in gold - then 7 years ago I heard about the PMs in electronics & that people were recovering the PMs from them - so (being a scrapper anyway) this caught my attention & I started researching it - the first thing I learned was that it involved the use of chemicals to recover the PMs

This put me on a journey of MANY hours of research to learn the chemical/chemistry processes involved in the recovery & refining of PMs

For about the first 6 months on this journey much of the info I was finding was ether incomplete info or flat out misinformation & safety was pretty much nonexistent as well as info on how to deal with the waste product produced

After the first 6 months of working off the limited info &/or mis-info I was finding in my research (the trial & error thing) I stumbled across a discussion forum about the recovery & refining of PMs (I will post a link to it at the end of this post)

The Gold Refining Forum is the "absolute" worlds best source of info &/or the discussion about the recovery of PMs - from the time I found it I became an "active" member - first as a student asking a LOT of questions & now as a well recognized teacher/consultant --- if my high school chemistry teach could see me now

The reason the gold refining forum is the world leader in info & discussion is because we have "active" members that are "world class" in the field of PM recovery & refining --- members that work(ed) for &/or owned LARGE refineries as well as active members (like myself) that are "successful" home "back yard" refiners that make there living from it --- you will not find a better source of info &/or discussion ANYWHERE --- here is a short list of some of our "professional" members

GSP (Gold Silver Pro) now retired from a life long of both owning his own refinery & working for "large" refineries

4metals - worked for as well as had his own refinery & now semi retired as a "consultant" (for many years) to both "large" & small refineries "around" the world

g_axelsson - is a physicist from Sweden

Lou - works for (he is the lead chemist) a "large" refinery & though they refine all PMs they specialize in PGM refining - there are few if any that know as much about refining PGMs then this man - unless you work for a company like Johnson Matthey

Deano - now retired from working 40 years in industrial scae mining in Australia (he IS your man when it come to ore)

The result of my being a member of the GRF is that I now have a small lab set up with a fume hood & fume scrubber system (which I built) a small ball mill (which is nothing more then a cement mixer) a concentrator table & two propane fired furnace's - one that take a #4 crucible (for "small" smelts & melting) & a larger one that takes a #40 crucible used primarily for smelting

I now make a "modest" living (for the last 5 & a half - 6 years) from the recovery & refining of PMs (as a home back yard operator) & utilize both leaching & smelting in my operation

The main source of my PMs come from electronics - which has "many" similarities in processes as processing ore - though they each have there own set of circumstances that make them each "somewhat" different

What I'm working on, with Mad Machinist as well

In the sort time I have been here I did see some threads by Mad Machinist which I have only "skimmed" (have not yet had time to really read & digest them) but interesting reading what I did read

Here is the thing --- the internet is FULL of misinformation &/or incomplete information - youtube videos are "the worst" - but also - there is a lot of info out there that consist of things like "research papers" written by university research teams that sound really good (& you would think you can trust them because they come from a university research team) but the problem is that though they can make it work in a "small" scale lab setting - the reality (all to often) is they are "not" practical &/or flat out do not work when scaled up to an actual "working" scale --- or there are companies trying to "sell" systems &/or processes that again simply don't work according to their claims

We (on the GRF) have in fact reviewed "many" of these papers &/or products & have proven many of them to be impractical on a working scale - systems that don't hold up to there claim, processes that amount to alchemy, & some that are out right scams

So - with all that said (sorry for the long post) I would like to recommend to both you & Mad Machinist to visit the GRF - you both seem to be intelligent people capable of "reasoning" discussion (we "do not" tolerate arrogant "know it all" types that become combative & argumentative)

I can "almost" assure you that if you join the GRF - introduce your self - post the material you are working with - the processes you have been trying to work with - the problems you have encountered - etc. --- that we will be able to get you headed down the path of "least" trial & error (there is "always" some of that involved) in attaining your goals --- & when you do encounter problems (in your trials) we can help you work through them - its the purpose of the forum & what we do - better then anyone else !!!

The GRF is "literally" - a gold mine - of info & discussion about PM recovery & refining

Here is the link --- GOLD REFINING FORUM - GOLD REFINERS HELPING ONE ANOTHER

Kurt

 

[Mad Machinist]

Hey all,

Figured I pop in and see what was up.

SaltwaterServr,

If you can get a few pics of those flotation cells so I can see what condition they are in, I can tell you if they are rebuildable or not. If you don't want them, I may come and get them for a project for my kid. He likes playing with the MIG welder I bought and he is getting pretty good at it too.

kurtak,

I've been in and out of the mining industry most of my life. I know all about the fly by night snake oil salesman that are trying to mine the miners. I've also seen a lot of processes that will work on a lab scale but are useless in the real world. We had a "bug farm" leaching process here. Worked great on a small scale but took too long on a larger scale when compared to leaching with sulfuric acid. Cost savings wasn't enough to justify the added wait time.

The process that SaltwaterServr and I are looing at will work on a smaller scale. The cost to set it up is a little steep but the savings in the end justifies the additional cost. With the bioleaching we are looking at, the bacteria will break down the arsenic in arsenopyrite thus removing the hazardous material disposal cost and opening up a lot more ore bodies for the small scale guy.

Not trying to brag or anything, but I hold two degrees. One in Environmental Science and one in Mechanical Engineering. I also have the services of a lot of other degreed professionals where I work as they are interested in this too.

I know what is said about bioleaching being impractical, but in fact it is being used on a large scale in multiple places across the world and most companies are rather reluctant to discuss their processes as many of them are "trade secrets".

I know about the Gold Refining Forum too. Lots of good people and lots of good information. Just some resistance to new ideas there.

Here's a good read on what we are up too. http://www.talvivaara.com/files/tal...Technical_Seminar_London_May_Presentation.pdf

 

[Mad Machinist]

kurtak,

You also have to understand that this would give us the ability to clean up many abandoned mine sites thus cleaning up both the environment and our reputations as miners. Right now I am trying to adjust the design to make the whole thing mobile to be easily moved from site to site.

 

[SaltwaterServr]

SaltwaterServr

Thank you for the reply further explaining your back ground & project(s) you are working on



Good to hear that you have a back ground in chemistry as that certainly gives you a clear understanding of the dangers of working with dangerous chems like concentrated H2O2 - you wouldn't believe how many people I have seen jump into this with absolutely NO knowledge what so ever but because they watched a couple youtube videos they think they know it all & no matter what you try to tell them they just wont listen until they have hurt them selves

An example of this is I recently received a batch of about 11 pounds of gold plated stainless steel from a guy to process - he originally had something like 150 pounds of this material (it was running 4.5 - 5 grams recovery per pound) so I asked him if he already processed 140 lbs why he just didn't finish the last 11 lbs - his reply - "because EVERYTHING in my garage AND house is now corroded & I have had to go to the hospital emergency twice - once to have my eyes flushed out (almost went blind) & once for breathing problems from breathing fumes

Safety is my number one concern when discussing this - which is why I made mention of it --- so knowing you have a back ground in chemistry is good to know

But you are also right - organic chemistry - & the chemistry involved in recovery &/or refining of PMs (Precious Metals) are two very different ball games

Now for a little back ground about myself --- until about 7 years ago I had absolutely NO back ground in chemistry - in fact in high school I got a Big Fat "F" in chemistry

25 - 30 years ago when I was living in Northern California I had some involvement in both placer mining & hard rock mining - I posted some about that here http://www.treasurenet.com/forums/g...rest-service-evicts-families-razes-homes.html (my post is on the second page)

So I already had an interest in gold - then 7 years ago I heard about the PMs in electronics & that people were recovering the PMs from them - so (being a scrapper anyway) this caught my attention & I started researching it - the first thing I learned was that it involved the use of chemicals to recover the PMs

This put me on a journey of MANY hours of research to learn the chemical/chemistry processes involved in the recovery & refining of PMs

For about the first 6 months on this journey much of the info I was finding was ether incomplete info or flat out misinformation & safety was pretty much nonexistent as well as info on how to deal with the waste product produced

After the first 6 months of working off the limited info &/or mis-info I was finding in my research (the trial & error thing) I stumbled across a discussion forum about the recovery & refining of PMs (I will post a link to it at the end of this post)

The Gold Refining Forum is the "absolute" worlds best source of info &/or the discussion about the recovery of PMs - from the time I found it I became an "active" member - first as a student asking a LOT of questions & now as a well recognized teacher/consultant --- if my high school chemistry teach could see me now

The reason the gold refining forum is the world leader in info & discussion is because we have "active" members that are "world class" in the field of PM recovery & refining --- members that work(ed) for &/or owned LARGE refineries as well as active members (like myself) that are "successful" home "back yard" refiners that make there living from it --- you will not find a better source of info &/or discussion ANYWHERE --- here is a short list of some of our "professional" members

GSP (Gold Silver Pro) now retired from a life long of both owning his own refinery & working for "large" refineries

4metals - worked for as well as had his own refinery & now semi retired as a "consultant" (for many years) to both "large" & small refineries "around" the world

g_axelsson - is a physicist from Sweden

Lou - works for (he is the lead chemist) a "large" refinery & though they refine all PMs they specialize in PGM refining - there are few if any that know as much about refining PGMs then this man - unless you work for a company like Johnson Matthey

Deano - now retired from working 40 years in industrial scae mining in Australia (he IS your man when it come to ore)

The result of my being a member of the GRF is that I now have a small lab set up with a fume hood & fume scrubber system (which I built) a small ball mill (which is nothing more then a cement mixer) a concentrator table & two propane fired furnace's - one that take a #4 crucible (for "small" smelts & melting) & a larger one that takes a #40 crucible used primarily for smelting

I now make a "modest" living (for the last 5 & a half - 6 years) from the recovery & refining of PMs (as a home back yard operator) & utilize both leaching & smelting in my operation

The main source of my PMs come from electronics - which has "many" similarities in processes as processing ore - though they each have there own set of circumstances that make them each "somewhat" different



In the sort time I have been here I did see some threads by Mad Machinist which I have only "skimmed" (have not yet had time to really read & digest them) but interesting reading what I did read

Here is the thing --- the internet is FULL of misinformation &/or incomplete information - youtube videos are "the worst" - but also - there is a lot of info out there that consist of things like "research papers" written by university research teams that sound really good (& you would think you can trust them because they come from a university research team) but the problem is that though they can make it work in a "small" scale lab setting - the reality (all to often) is they are "not" practical &/or flat out do not work when scaled up to an actual "working" scale --- or there are companies trying to "sell" systems &/or processes that again simply don't work according to their claims

We (on the GRF) have in fact reviewed "many" of these papers &/or products & have proven many of them to be impractical on a working scale - systems that don't hold up to there claim, processes that amount to alchemy, & some that are out right scams

So - with all that said (sorry for the long post) I would like to recommend to both you & Mad Machinist to visit the GRF - you both seem to be intelligent people capable of "reasoning" discussion (we "do not" tolerate arrogant "know it all" types that become combative & argumentative)

I can "almost" assure you that if you join the GRF - introduce your self - post the material you are working with - the processes you have been trying to work with - the problems you have encountered - etc. --- that we will be able to get you headed down the path of "least" trial & error (there is "always" some of that involved) in attaining your goals --- & when you do encounter problems (in your trials) we can help you work through them - its the purpose of the forum & what we do - better then anyone else !!!

The GRF is "literally" - a gold mine - of info & discussion about PM recovery & refining

Here is the link --- GOLD REFINING FORUM - GOLD REFINERS HELPING ONE ANOTHER

Kurt

I've been over on GRF more than just a few times.

People really don't realize some of the stuff they're playing with. Most, most people will give proper care to acids, but don't realize the dangers of highly oxidative or highly alkaline substances.

You could ask 100 people if hydrogen peroxide can be dangerous and maybe 1 person would say yes and tell you about the Kursk incident. The rest think it's just a little stronger version of what you buy at the store, not knowing the punch it can have in certain reactions.

Funny you mention the lab scale to working scale, I was just talking to another miner about that on FB last night while looking at each other's geology we're mining. He had a new process he found online, researched it, and figured out that unless you were dissolving gold disks in a lab, it was worthless.

I'll probably join GRF eventually, just a little busy at the moment with my Cowboys kicking the *** of everyone in the NFL.

 

[SaltwaterServr]

Hey all,

Figured I pop in and see what was up.

SaltwaterServr,

If you can get a few pics of those flotation cells so I can see what condition they are in, I can tell you if they are rebuildable or not. If you don't want them, I may come and get them for a project for my kid. He likes playing with the MIG welder I bought and he is getting pretty good at it too.

kurtak,

I've been in and out of the mining industry most of my life. I know all about the fly by night snake oil salesman that are trying to mine the miners. I've also seen a lot of processes that will work on a lab scale but are useless in the real world. We had a "bug farm" leaching process here. Worked great on a small scale but took too long on a larger scale when compared to leaching with sulfuric acid. Cost savings wasn't enough to justify the added wait time.

The process that SaltwaterServr and I are looing at will work on a smaller scale. The cost to set it up is a little steep but the savings in the end justifies the additional cost. With the bioleaching we are looking at, the bacteria will break down the arsenic in arsenopyrite thus removing the hazardous material disposal cost and opening up a lot more ore bodies for the small scale guy.

Not trying to brag or anything, but I hold two degrees. One in Environmental Science and one in Mechanical Engineering. I also have the services of a lot of other degreed professionals where I work as they are interested in this too.

I know what is said about bioleaching being impractical, but in fact it is being used on a large scale in multiple places across the world and most companies are rather reluctant to discuss their processes as many of them are "trade secrets".

I know about the Gold Refining Forum too. Lots of good people and lots of good information. Just some resistance to new ideas there.

Here's a good read on what we are up too. http://www.talvivaara.com/files/tal...Technical_Seminar_London_May_Presentation.pdf

I should've been more clear. There's not two cells, there are two banks of cells. I think each has 4 or 6 compartments. Getting them out of where they are is going to be a royal Hillary. The road is gone and there are rocks the size of VW's after a flash flood about 8 or 9 years ago I say. It completely washed out a pretty dang robust ore trestle going across the wash. If they're in good enough shape and we can move them, we're going to get them for sure.

 

[kurtak]

Thanks for the replies guys !

I wont have time to reply today & it may be a few days before I have time

Today I have to recover what should be an ozt plus (I hope its plus) of gold from solution & as well a couple pounds of silver from solution

This is from a smelt I recently did where I used silver as the collector - my expectation from the smelt is an ozt plus Au - an additional 1/2 pound (+/-) Ag as well as some Pd

Then I only have a couple more days of warm weather to get some warm weather things done before the weather takes a nose dive on Friday down to freezing temps

Kurt

 

[Mad Machinist]

I should've been more clear. There's not two cells, there are two banks of cells. I think each has 4 or 6 compartments. Getting them out of where they are is going to be a royal Hillary. The road is gone and there are rocks the size of VW's after a flash flood about 8 or 9 years ago I say. It completely washed out a pretty dang robust ore trestle going across the wash. If they're in good enough shape and we can move them, we're going to get them for sure.

Let me know when and I'll do everything I can to get down there and give you a hand. Hopefully by then I'll have the winch on the front of my truck. Have some things of my own to recover.

 

[kurtak]

The process that SaltwaterServr and I are looing at will work on a smaller scale. The cost to set it up is a little steep but the savings in the end justifies the additional cost. With the bioleaching we are looking at, the bacteria will break down the arsenic in arsenopyrite thus removing the hazardous material disposal cost and opening up a lot more ore bodies for the small scale guy

I have taken some time to read some of your & SaltwaterServr other threads about what you guys are working on - interesting reading I must say - at this point I can't say I have fully digested &/or wrapped my head around it all

So quick question per the underlined in the above quote to clarify my understanding --- the purpose of the bioleaching is to deal with the arsenopyrite which posses a hazardous waste problem with "other" chemical leaching & as well chemical leaching of arsenopyrite ores presents problems with getting full effective leaching of the gold --- so the bioleaching doesn't actually leach the gold - but rather deals with the arsenopyrite in an Eco friendly way - followed by (better) chemical leaching for the gold that is arsenic free as a waste produce after recovery of the gold ?

Kurt

 

[Mad Machinist]

I have taken some time to read some of your & SaltwaterServr other threads about what you guys are working on - interesting reading I must say - at this point I can't say I have fully digested &/or wrapped my head around it all

So quick question per the underlined in the above quote to clarify my understanding --- the purpose of the bioleaching is to deal with the arsenopyrite which posses a hazardous waste problem with "other" chemical leaching & as well chemical leaching of arsenopyrite ores presents problems with getting full effective leaching of the gold --- so the bioleaching doesn't actually leach the gold - but rather deals with the arsenopyrite in an Eco friendly way - followed by (better) chemical leaching for the gold that is arsenic free as a waste produce after recovery of the gold ?

Kurt

More or less. The bacteria attack and consume the sulfides turning them into sulfuric acid. The sulfuric acid then dissolves all the base metals. Through the bacterial action, the arsenic is combined with the iron present to become ferric arsenate effectively locking up the arsenic into a stable substance that is inert and nonhazardous.

The gold and other PM are not effected by the action and can be removed by any normal process such as carbon in pulp or electrowinning. This process also has the advantage of being able to recover any dissolved base metals through selective electrowinning. Although I am still working out the selective part. I'm wondering if one of the lab style adjustable power supplies would work for that.

Like I said, it will be a little more expensive to set up but I think the advantages are better. Recovering the base metals may not be profitable or as profitable as recovering the PM but if the base metal recovery can pay some or all of the operating costs, then that is that much more profit from the PM that goes into ones pocket. And as an added bonus, if the base metals are not in the tailings discharge then there is zero chance they can pollute.

 

[kurtak]

More or less. The bacteria attack and consume the sulfides turning them into sulfuric acid. The sulfuric acid then dissolves all the base metals. Through the bacterial action, the arsenic is combined with the iron present to become ferric arsenate effectively locking up the arsenic into a stable substance that is inert and nonhazardous.

Thanks for the reply Mad Machinist - just wanted to make sure I had the "basic" understanding of what you guys are working on somewhat wrapped around my head - as I said - its been some interesting reading !

The gold and other PM are not effected by the action and can be removed by any normal process such as carbon in pulp or electrowinning. This process also has the advantage of being able to recover any dissolved base metals through selective electrowinning. Although I am still working out the selective part. I'm wondering if one of the lab style adjustable power supplies would work for that.

Don't bang your head against the wall to hard trying to figure out "selective" electro winning - if you are thinking you can "selective" win different metals by "adjusting" the volt/amp setting to match the "electromotive series" of different metals & thereby win the metals selectively --- it just doesn't work that way (at least not to any degree of being truly selective)

In the metals recovery/refining/plating industry you have 4 basic kinds of electrolytic cells --- refining cells - winning cells - striping cells & plating cells --- for this discussion there is no need to discuss the striping & plating cell

Lets start with the "refining" cell --- this cell is "to a point" a "selective" electro-cell - & although volt/amps play a part in the operation of the cell - the volt/amps have nothing to do with it being selective in turning out a "refined" product - rather the electrolyte is what makes it selective

The 2 most common refining cells (though certainly not limited to) are the copper refining cell & the silver refining cell

The reason they are selective & therefore able to turn out a 999 & even 9999 or 99999 product is because you are "starting" the cell with an electrolyte that is "pregnant" with the metal you are trying to purify (copper or silver)

Lets look at the silver cell - the purpose of it is to take silver that is less then 999 (as your anode) & "part" the silver from that anode & deposit it to the cathode as 999 (or better) silver

So - you make up an electrolyte by dissolving pure silver with nitric acid & you want the acid absolutely pregnant with silver (as a note when dissolving the silver & assuming your using 67 - 70% nitric you "have to" dilute the nitric 50/50 with "distilled" water - & once you have your "pregnant" silver nitrate - it is further diluted for the electrolyte in the cell)

Once you have the electrolyte in your cell - hook you positive DC power lead to the anode & negative DC power lead to the cathode - turn the power on - & what happens is that the current (amps) cause silver ions to be "displaced" from the electrolyte thereby depositing them at the cathode as pure silver metal (due to the electrolyte being pure dissolved silver)

Now - because silver ions are being displaced from the electrolyte - it is also "freeing up" nitric acid - which makes nitric acid available to dissolve metal from the anode --- so the free nitric will dissolve any metals in the anode "that are soluble" with nitric (such as copper nickel, palladium to name a few) & metals that are not soluble with nitric (such as gold, platinum etc.) stay trapped in the anode bag

Because other metals besides silver are being dissolved into the electrolyte the electrolyte is slowly being corrupted - but "to a point" that is not a problem - that is - as long as the silver ions in the electrolyte are the predominant (higher concentration) ions - the silver ions are what continue to be displaced - it is only when the electrolyte becomes corrupt enough with other nitric soluble metal ions - that there are not enough silver ions to allow for silver only deposit at the cathode - that you "start" to get "co-deposit" of the other metals

So it is the concentration of metal ions in the electrolyte in a parting (refining) cell that determines metal deposit at the cathode - changing volt/amps will only change rate of deposit & density of (fine or course) deposit

The winning cell works on the same basic principle - it displaces the metal ions that make up the electrolyte - the only real difference is that with a winning cell you run it with an inert anode (such as high density carbon or platinum plated titanium)

Therefore - because the anode is inert - as metal ions are displaced from the electrolyte - the anode is not providing metal ion replacement to the electrolyte - so the electrolyte really has no choice but to give up its metal ions as is &/or whatever they are - the result being a co-depositing of winnable metals in the electrolyte --- not all metals are winnable (example; - iron for the most part is not winnable)

What you "may" get when you first start the cell - is a greater (but still co-deposited) winning of the higher metal ion concentration - but that will drop off quickly with increasing co-depositing as the cell runs

The up side of running a winning cell (besides recovery of the "winnable" metals) is that it also gives you back a reusable leach solution whether its an acid leach or cyanide leach (somewhat determined by corruption of the non-winnable metals - but reusable non the less)

And speaking of cyanide --- if you use a winning cell to recover you metals from a cyanide leach - not only do you get the leach back for reuse - but once your cyanide becomes to corrupt with non-winnable metals to reuse it - you can run the cyanide through it for "complete" destruction of the CN - its just a matter of switching the polarity on the cell & then when you run the CN though it you will get complete destruction of the CN (there are a few details to doing it - but switching the polarity is the way its done)

& yes an adjustable power supply will work for a winning cell --- 0 - 10 or 15 volt is all you will ever need on the volt side --- 0 - 30 amp is the least I would go with on the amp side --- the bigger on the amp side the better as it is the amp output that determines the size cell you can run

Kurt

 

[Mad Machinist]

Kurtak,

Thank you for the explanation. This is one part of the process i have never messed with. Guess its back to the drawing board on this section of the plan.

 

[distribuidorUSA]

Kurt. Thank you for your detailed information regarding the cells..could you elaborate on big scale cells requirements .as to gallon size,anode size and current?.can I process a 50 lb anode for example of mainly Silver ore concentrate ?.what size a cell shoul I build and of what material?..how many gallons of electrolyte should I use and what silver content should it have?..does the cathode should be of pure silver?.and what current should I use fo a specific cell size?..thank you for your information.

 

[kurtak]

Kurt. Thank you for your detailed information regarding the cells..could you elaborate on big scale cells requirements .as to gallon size,anode size and current?.can I process a 50 lb anode for example of mainly Silver ore concentrate ?.what size a cell shoul I build and of what material?..how many gallons of electrolyte should I use and what silver content should it have?..does the cathode should be of pure silver?.and what current should I use fo a specific cell size?..thank you for your information.

Hmmmm - so you want me to right a book --- just kidding - there are a lot of variables & as well parameters change during the actual running of the cell - meaning there is somewhat of a learning by doing curve to it - its not an "exact" science

However there are certain standards (though not set in stone) used to build - set up & run a parting cell

lets start with what I underlined in the above quote --- the parting cell is not really designed to recover &/or refine silver from silver ore - even as a concentrate --- its designed to part silver (as pure silver) from an anode of actual metal that is "primarily" silver but not pure silver using DC current to facilitate the transfer of silver from anode to cathode --- that means the current needs to make contact (flow through) the metal in order to work

So the first problem with trying to use a silver cell to recover silver from ore (even as concentrates) is that ore (crushed) is made up of a combination of metal (&/or there complexes) & "inert" components (rock) --- so - though the current "may" find a path from metal particle to metal particle facilitating transfer from anode to cathode --- much of the silver is going to be "insulated" from current flow due to being surrounded by the inert (rock) fraction of the ore

In other words - though you will get some silver to part from the ore - you are also still going to have silver left behind in the ore concentrate --- also if the ore is made up of (in whole or in part) a silver complex (silver sulfide, etc.) the cell will have no effect on the complex - only the actual metal fraction would be effected - and - metals other then silver in the concentrates (especially if in high concentration) are going to effect electrolyte corruption

Therefore - the parting (refining) cell is really designed to part the "primary" metal (silver - copper - etc.) of an anode (poured as a bar or as shot) from the anode as pure metal - to the cathode - leaving the impurities behind in ether the anode bag or in the electrolyte --- in other words its used to part/purify a primary metal with some contamination that has been "recovered" from ether a leach process &/or smelting process

That said - because I don't want high jack this thread to much from its original purpose of discussion - think I will go ahead & start a new thread specific to the discussion of setting up & running electrolytic cells (for both parting & winning)

Give me a few days to get that thread going as I will need a few days to think about just how/where to start the thread - AND - its deer gun season here so am spending time in the woods right now - have one in the freezer from bow hunting - but would sure like to put another one in the freezer

Kurt

 

[distribuidorUSA]

Thank you again.. we'll be paying attention to your thread.
and happy thanksgiving to All Friends!!!!.