# Gold recovery through cyanidation with activated carbon



## sohwohn (Dec 25, 2017)

I used 300g of sample (Gold grade: 27ppm) and 700cc tap water to perform the cyanidation process.

The process took 3 hours and I filtered the solution to separate liquid and sample powders.

I then put 15g of activated carbon into the filtered solution and stirred the mixture for about 90 minutes.

The carbon cubes were then taken out and put into a little furnace and burnt to ashes (around 0.3g).

I found the carbon had around 40% Cu and 0.3% Au with little amount of base metals like Fe, Pb, Zn, etc..

My goal is to repeat this process until I get enough Au and then I make a gold alloy.

My question is, how do I recover Au from the burnt ashes of activated carbon?

I tried my furnace and the temperature was almost about 1200 degree Celsius.

I did find a little bead at the bottom of the furnace cup but I couldn't remove it.

Then I added Cu2O with carbon powders into the furnace cup again hoping that it would make enough volume for the alloy mixture to flow out. But I messed up by putting too much Cu2O powders and now the outcome alloy looks like a mess and the X-ray spectrum only shows very very little reading of Au.

I'm wondering if there's better way to recover gold from the burnt ashes?

I looked up the Internet and it seems like I'm dealing with AuCN- but I have no idea what should I do next.


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## sohwohn (Dec 25, 2017)

Also, I actually have another question. I read X-ray spectrum to determine the concentrations of elements in the carbon sample. The presence of Cu doesn't affect me at all but little Zinc can interfere Gold by very very much.

I found out that, after I put the activated carbon cubes into the solution, for first 10-15 mins, I can have a very very clear Au peaks as Zn is not disturbing. However, after 30 mins, there are more and more Zinc incoming and at some point the Au peaks are gone.

So I'm wondering (which I will be doing tomorrow) if I should put 20g of carbon and collect them after 20 mins and repeat the process until I don't see Au in the sample anymore. I know this sounds stupid and may cost me a lot of carbon powders but I'm not trying to refine the process. I just want to be 100% sure I'm getting Gold. If I get too much Zinc, I won't know even Au is there.


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## sohwohn (Dec 25, 2017)

I also wonder..

I mixed Cu2O with carbon aiming to reduce Cu2O into Cu. Was it a correct concept?


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## Reno Chris (Dec 26, 2017)

First, a little math. You have 0.3 grams of ash and it has .3 % gold. This means you have (.3 x.003) or a little less than one thousandth of a gram of gold - roughly about 4 cents worth of gold. You could do this same procedure 500 times and have less than a half gram of gold even if everything went perfect. Its a whole lot of work for a tiny amount of gold.
Second, cyanide is a common treatment but it does not work directly with all ores. Some require special treatment prior to cyanide to allow the cyanide process to work - especially those with significant sulfides and some with certain base metal minerals. In order to use cyanide successfully, you need to know your chemistry well. You need to know your ores well. There are books, some of which are available for free download which explain the basics of cyanide treatment of gold ore. It seems like you may need to read a few of these. 
Its way beyond the scope of a forum to teach the necessary chemistry and we cant guess what kind of ore you have either. The number of possible problems are huge and we dont have the info necessary about what you are doing to even give a guess.


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## sohwohn (Dec 26, 2017)

Reno Chris said:


> First, a little math. You have 0.3 grams of ash and it has .3 % gold. This means you have (.3 x.003) or a little less than one thousandth of a gram of gold - roughly about 4 cents worth of gold. You could do this same procedure 500 times and have less than a half gram of gold even if everything went perfect. Its a whole lot of work for a tiny amount of gold.
> Second, cyanide is a common treatment but it does not work directly with all ores. Some require special treatment prior to cyanide to allow the cyanide process to work - especially those with significant sulfides and some with certain base metal minerals. In order to use cyanide successfully, you need to know your chemistry well. You need to know your ores well. There are books, some of which are available for free download which explain the basics of cyanide treatment of gold ore. It seems like you may need to read a few of these.
> Its way beyond the scope of a forum to teach the necessary chemistry and we cant guess what kind of ore you have either. The number of possible problems are huge and we dont have the info necessary about what you are doing to even give a guess.


You're right..

Thank you for the reply.

The ore doesn't have much Sulfides but almost 35% Lead and Zinc Oxides. However, the cyanidation chemical I'm using doesn't absorb Pb, Zn, Fe out of the ore so it should be fine. Mainly the cyanidation chemical absorbs Cu and Au. The cyanidation process takes only 2 hours for 300g of ore, and it only takes 5 mins for the carbon to absorb the AuCN compounds. The Au grade in AC has increased but I have yet had an exact number. I have made another setup yesterday and I obtained some more AC which will be examined later.

For what I'm assuming: The cyanidation chemical absorbs Cu and Au first, given time it will start to absorb Pb, Zn and Fe. The AC works the same way.

Yesterday, I did an experiment, I picked up a carbon cube by every 5 mins and examined the Cu, Zn, Au concentrations. The Zn Au concentrations soon reach their peaks and they stop growing. The only thing keeps growing is the Cu peak. So I assume, the more Cu I get, the less Au I have after I burn the carbon into ashes. Also, I have found out that the longer I perform the cyanidation process, the more Zinc I get in the solution. However, gold grade in the solution didn't seem changing.


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## sohwohn (Dec 26, 2017)

The thing which bothers me most and I can't find an answer online is that..

People say I can just smelt the ashes to get solid metal bead.

How much temperature? Anything else I need to add into the furnace cup?

I have spent a lot of time searching for an answer but it only comes up with 'desorbing the AC'..


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## nickvc (Dec 27, 2017)

You can make your leach more selective by reducing the amount of free cyanide you have.
Read Delano’s threads things that may be of interest to members and further things etc it may give you better guidance.


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## sohwohn (Dec 27, 2017)

nickvc said:


> You can make your leach more selective by reducing the amount of free cyanide you have.
> Read Delano’s threads things that may be of interest to members and further things etc it may give you better guidance.


Are you suggesting if I add different amount of cyanidation chemicals it will be more Au favorable / Zn favorable?!

Oh my god! If that's true, I must make some tests to evaluate the best concentrations of cyanidation chemicals to enhance the Au grade in solution!!

I couldn't find member 'Delano' in this forum.. What's his member ID?

Thank you very much!!!!


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## FrugalRefiner (Dec 27, 2017)

sohwohn said:


> I couldn't find member 'Delano' in this forum.. What's his member ID?


His name is Deano.

Dave


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## kurtak (Dec 27, 2017)

FrugalRefiner said:


> sohwohn said:
> 
> 
> > I couldn't find member 'Delano' in this forum.. What's his member ID?
> ...



Here are links to the threads suggested for reading 

:arrow: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=85&t=22668

:arrow: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=22978 

When it comes to the treatment of "ore" for gold recovery & refining you will have a hard time finding better &/or more complete info about it then what Deano has been so kind in taking his time to provide right here :!: :!: :!: 

THANK YOU Deano :!: for providing this HUGE contribution to the forum :!: 8) 8) 

sohwohn; - these are 2 very long threads - but - they are well worth taking the time to read "completely" --- as well as researching (& reading) other things Deano has posted in other threads

In fact - you will likely find that the info Deano has provided here (concerning the treatment of ore) is so vast - that its not just going to be a simple read --- in other words - I think you will find it to be a "study" --- meaning taking note & referring back to it in order to really grasp "all" the info Deano has been so kind to provide here

Kurt


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## cuchugold (Dec 27, 2017)

kurtak said:


> FrugalRefiner said:
> 
> 
> > sohwohn said:
> ...


Yes. Thanks Deano.


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## Deano (Dec 27, 2017)

You have two possibilities for adsorbing gold values onto activated carbon.

The first is where you are adsorbing from a clean liquor with no fine solids present.

In this case you can get very good gold recoveries by ashing the carbon and smelting the ash.

If you have fine ore particles present in the liquor you will get some of these particles caught in the carbon pores and they will be present in the ash no matter how diligently you wash the carbon before ashing.

These residual particles will cause gold losses of up to 50% of the gold if you smelt the ash.

The only way to get high recovery from such ashes is by leaching the gold with either cyanide or aqua regia.

Other gold leaches will also give high recoveries but are a pain to use apart from the pH7 hypochlorite leaches for which you need Eh/pH meters, the meter expense tends to put people off these leaches which is a shame as they are probably the safest leaches for both small and large operators provided basic safety precautions are taken.

Deano


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## sohwohn (Dec 27, 2017)

Oh my god I'm so glad I found this forum as I had no one to talk to until now..

I had yet read Deano's threads but I definitely will. Before I could actually do so I can't believe Deano is actually replying my thread!! Thank you Deano and all of you who're helping me.

I came to China from Hong Kong about three months ago. Before I was living in Hong Kong and was an Interior Designer. My father is getting old and after considerations I decided to come helping him with his projects. Here has limited facilities and people. So basically I'm my own teacher. With the help from my friend purchasing VPN for me so that I can google, I started from nothing and learning little by little. I started with the X-ray spectrum assaying. I spent almost two and a half months to finally figure how to 'tune' the machine and make use of the standards and so to finally perform an semi-quantitative analysis on ore samples. Also now I can smelt ore samples on a Copper plate and hence provide ppm-level analysis on precious metals. However, I was only good at the software part (since I graduated in I.T. major), but not the hardware part.

Recently (among last 2-3 weeks) I had been doing acids/cyanidation/smelting by my own. I only have very very very very very very.. basic ideas of chemistry so I had a hard time. I studied Chemistry when I was secondary school but I picked Physics and Pure Mathematics for my high school subjects, and Information Engineering in University.. So I had been doing was googling and googling and googling..

Anyway, thank you very much for replying this thread and I guess I will first spend sometime on reading Deano's threads, before I make any updates.

Sohwohn


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## sohwohn (Dec 27, 2017)

Deano said:


> You have two possibilities for adsorbing gold values onto activated carbon.
> 
> The first is where you are adsorbing from a clean liquor with no fine solids present.
> 
> ...


So, are you suggesting, if I filter the solution for like 2-3 more times, it will help induce the gold grade on AC?

I'm not sure I should ask questions now as I just woke up and yet read your threads (it's China and my morning should be your evening).

Also, I actually have some assumptions as I have run 4 experiments and I'm just guessing the factors. I assume (1) the longer the cyanidation takes place the more Cu, Zn I get into the solution (2) the longer time given to AC absorption the higher concentrations of Cu, Zn will be (3) the more AC I add one time the sooner the gold grade drops and hence higher risk

So, for what I'm assuming, I will run an experiment today, I will spend only 1 hour on cyanidation and 5 mins on each AC absorption run and maybe 3-4 runs would be enough. Also, I will filter the solution 3 times to reduce the fine particles as much as possible.

Reading Deano's threads and performing such experiment, is my today schedule.


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## nickvc (Dec 28, 2017)

Take your time reading Deanos threads and comments he gives a lot away but expects you to join the dots on many aspects he discusses, the clues are all there it’s up to you to make sense of them and follow his line of thought.


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## Deano (Dec 28, 2017)

Activated carbon will basically adsorb all metallic ions from solution, the heavier the ions the more likely they are to displace lighter ions.

However the concentration of each ion species also plays a major part in that a high concentration of lighter ions can prevent or slow down adsorption of a low concentration of heavier ions.

The presence of ore solids will not greatly affect the adsorption of metal ions unless the ore particle sizes are such that they can enter the carbon pores and prevent metal ion access to these pores.

Adsorption onto activated carbon is a relatively slow process even if a clean liquor is pumped through a column of carbon, you pick up the high end of the gold values fairly quickly but once the outer surface of the carbon has been loaded the adsorption occurs in the pore structures and this is much slower.

Activated carbon is always used as a transfer medium, you are either loading it with values which are later to be desorbed in a more concentrated form or you are going to ash it and treat the ash to recover the values,

The only times that carbon is not used as a transfer medium are when it is loaded with pollutants and disposed of in a waste facility, even here the carbon has effectively transferred the pollutants to a safer environment in a more concentrated form.

Deano


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## sohwohn (Dec 28, 2017)

Deano said:


> Activated carbon will basically adsorb all metallic ions from solution, the heavier the ions the more likely they are to displace lighter ions.
> 
> However the concentration of each ion species also plays a major part in that a high concentration of lighter ions can prevent or slow down adsorption of a low concentration of heavier ions.
> 
> ...


Sir Deano you are being really really helpful to me!!

I wonder, as you have said, 'or you are going to ash it and treat the ash to recover the values', we actually have an induction furnace (up to 1300 degree Celsius), what can I do to the ashes?

Ps. What I'm doing here is just to prove 'this ore can be done by cyanidation' and estimate the recovery rate. The large-scale process will be done by selling the AC in the end. People use ICP to determine the gold grade so even the AC has large scale of Zn it's not an issue. However, speaking of assaying, we here only have a XRS machine, which is great, for semi-quantitative analysis. Though we encounter an issue that if Au concentration is lower than 50ppm then it will not show X-ray spectrum peaks or it will be interfered (covered) by Zn-Kb peak.. You said..



> Adsorption onto activated carbon is a relatively slow process even if a clean liquor is pumped through a column of carbon, you pick up the high end of the gold values fairly quickly but once the outer surface of the carbon has been loaded the adsorption occurs in the pore structures and this is much slower.



and I totally agree. The Au grade keeps climbing up but the issue is so are other elements. So your explanation has explained everything I observed. The problem I'm getting here is that I have dissolve too many other elements, which disturb me assaying Au grade. Or I can just put the AC there and stir for like a day or two to maximize the Au grade. Anyway, I'm still reading your threads and getting the picture clearer than ever. Thank you very much as I'm making significant progress on understanding 'what's happening behind the scene'.


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## sohwohn (Dec 29, 2017)

I have read some of Deano's articles and replies, by filtering Deano's posts by keyword 'cyanide'. The posts are extremely helpful and I am taking time to connect the dots..

I have run out of sample powders and the sites are sending more samples to the lab. I'll have meetings tomorrow so I won't be able to carry out more experiments.

What I've discovered through my own tests/experiments:
1. It seems like the cyanidation chemical I'm using prefers to dissolve Cu then Fe/Mn then Zn/Pb at 2%. To make it more selective I guess it's to decrease the concentration to about 0.5% or even 0.1%.
2. The AC (coconut shell) I'm using absorbs Fe slowly but quite significantly on Cu. This is my guess and assumption because Ore-A (10% Fe, <1% Cu, Zn, Pb, 25ppm Au) is performing quite well (as described by Deano) the AC mostly absorbs Au and not much Fe and Mn, but almost no Cu, Zn and Pb. Ore-B (5% Pb, 3% Zn, 1% Cu, 50ppm Au) contains so much Cu and Zn in AC as I can observe the Au peak stops in certain level and Cu/Zn concentrations keep climbing and climbing. I guess it's due to the excess dissolve-rate of Cu and Zn.

I will make some time after tomorrow to make a relatively complete report on what ores I'm handling and what I've got from the experiment results.

Thanks everyone again as this is a perfect place for me to get and share ideas about what I'm doing.. My friends in Hong Kong support me but they don't understand the details so I basically had no one to discussed with and felt like I was fighting alone.


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## nickvc (Dec 29, 2017)

You are reading and studying so help and advice will keep coming, we try to stresss to all new members that they have to do their part and you certainly are and so will get help as and when we can advise.


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## Deano (Dec 29, 2017)

The mining industry standard cyanide level is 0.1% sodium cyanide in solution, this is around 500ppm actual CN-.

You can play with lesser cyanide concentrations in order to minimise base metal dissolution and relatively enhance the gold dissolution.

High copper ores can be run with cyanide levels at 0.01% or even lower.

As the cyanide level is lowered the protective alkalinity will also lower so you will have to add lime or caustic for pH regulation.

Induction furnaces are not useful for carbon ashing, you need to have an air flow through the carbon with the temperature around 650C. Ashing needs to be complete. Get yourself an electric muffle furnace and some porcelain dishes for the ashing.

Usually you monitor the metals in solution values to see how the leach is going, get yourself a good second hand AAS unit to do this with.

Selling loaded carbon is usually an opportunity for dodgy assay methods to be used, much smarter to do your own stripping and then reuse the carbon, that way you maintain control over the gold.

Carbon in leach levels are usually around 5 grams per litre, much higher and attrition of the carbon becomes a major issue. Gentle agitation is needed.

Deano


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## sohwohn (Dec 29, 2017)

Deano said:


> The mining industry standard cyanide level is 0.1% sodium cyanide in solution, this is around 500ppm actual CN-.
> 
> You can play with lesser cyanide concentrations in order to minimise base metal dissolution and relatively enhance the gold dissolution.
> 
> ...


Yes! We're ordering muffle furnace, and checking the price of AAS unit. We have muffle furnace and AAS unit in our another factory (Jewerly manufacturor) but not in this small lab.

Regarding the cyanide cocentration, I guess I had been doing too wrong. I will run some more experiments on the Cu-1% ore with much lower concentrations.

Here's a tricky question I wonder: Regardless of the matrix metals, does the increase of cyanide concentration induce the cyanidation speed? I know I may seem greedy and matrix metals can mostly like NOT TO BE IGNORED, but I just wonder.


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## nickvc (Dec 30, 2017)

I know I’m not Deano but as you increase the amount of cyanide in your solution it does speed up recovery at first but it also increases the amount of base metals taken into solution so eventually slowing the reaction down and making recovery harder, the idea is to make your solution more selective, if you can keep the solution moving allowing fresh solution to wash over the material it will help increase the speed of dissolution.


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## sohwohn (Dec 30, 2017)

nickvc said:


> I know I’m not Deano but as you increase the amount of cyanide in your solution it does speed up recovery at first but it also increases the amount of base metals taken into solution so eventually slowing the reaction down and making recovery harder, the idea is to make your solution more selective,


Ohh..! Got it! Thank you!



> if you can keep the solution moving allowing fresh solution to wash over the material it will help increase the speed of dissolution.


Is it because the Au dissolution rate decreases while concentration of gold cyanide increases? Or is it because the 'fresh solution' has guaranteed concentration of free cyanide (like no matter how long time goes by, it stays at certain concentration)?


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## nickvc (Dec 30, 2017)

By moving the solution continually you expose the gold to fresh solution which in turn can dissolve more gold, it’s similar to heating AR it helps the dissolution by making the molecules move faster.


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## sohwohn (Dec 30, 2017)

nickvc said:


> By moving the solution continually you expose the gold to fresh solution which in turn can dissolve more gold, it’s similar to heating AR it helps the dissolution by making the molecules move faster.


You mean to stir the solution, right? I do!


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## anachronism (Dec 31, 2017)

Stirring is a good start however Nick's referring to a constant movement without the need to physically do it. 

People have discussed an inert bucket arrangement on a cement mixer with a variable speed motor as an option. A sharp eyed friend of mine (John) who is a member on here in the UK found this in a scrap yard a couple of weeks ago and paid £100 for it. It works. Not sure whether the bucket is Stainless Steel or Titanium yet but I'll know next week when it's up here and XRFed. Nickvc will laugh at me for having one of these. A lot.


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## sohwohn (Dec 31, 2017)

anachronism said:


> Stirring is a good start however Nick's referring to a constant movement without the need to physically do it.
> 
> People have discussed an inert bucket arrangement on a cement mixer with a variable speed motor as an option. A sharp eyed friend of mine (John) who is a member on here in the UK found this in a scrap yard a couple of weeks ago and paid £100 for it. It works. Not sure whether the bucket is Stainless Steel or Titanium yet but I'll know next week when it's up here and XRFed. Nickvc will laugh at me for having one of these. A lot.


From this angle I can't tell what this is..

Maybe due to the fact that English is not my mother language, I didn't mean I would stir the solution with my precious hands. We have something like this:


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## anachronism (Dec 31, 2017)

That's a good start- a little fast though - then again if you have a vortex it will aerate the solution and introduce oxygen into the liquor which will provide the oxidant you need without the need to add m-NBSS.

I've rotated the picture above so it makes more sense. Apologies I hadn't had coffee when I originally posted it.


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## sohwohn (Dec 31, 2017)

anachronism said:


> That's a good start- a little fast though - then again if you have a vortex it will aerate the solution and introduce oxygen into the liquor which will provide the oxidant you need without the need to add m-NBSS.
> 
> I've rotated the picture above so it makes more sense. Apologies I hadn't had coffee when I originally posted it.


I thought faster the better. If too slow, some powders stay at bottom. This is faster than what I need to avoid that though.

This is what we use for grinding:



This is a small flotation unit but I seldom use 'cause it's too difficult to actually achieve something by using it. I feel like it's too advanced for me:



This is my working area and that metal box is the XRF unit:



This is our induction furnace which will soon be replaced by a muffle furnace (yay!) in a month:



This is our furnace cup:


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## anachronism (Dec 31, 2017)

Thanks for the extra info. My experience is related to ewaste and not mining so RenoChris and Deano will have a much more valid input than me.


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## sohwohn (Dec 31, 2017)

I've came here for about 3-4 months. The first month I spent all time tuning the XRF unit and making use of it. These show some of my work:


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## sohwohn (Dec 31, 2017)

I've been trying flotation and cyanidation for the past 2 weeks.

My last run:
Ore powders used: 300g grinded to -74nm (fire-assayed: 50ppm Au, and 250ppm Pt)
Water used: 1200cc tap water
pH adjustment: Na2CO3 used, pH 11-12
Cyanide used: 25g (Conc: 2%) for 2 hours
AC: 20g for 2 hours
Result: .37g ashes, 4556ppm Au, implying roughly 1.69mg Au

The 300g should contain 15mg Au so the recovery rate is about 11.2%. I'm not certain about if this is the way to calculate but this is my way.

My current run:
Ore powerders used: 240g grinded
Water used: 1500cc tap water
pH adjustment: Na2CO3 used, pH 11-12
Cyanide used: 1.5g (Conc: 0.1%) for 16 hours
AC: 5g for 8 hours, then another 5g for 8 hours

I'm putting this much of water because we don't have titration equipment yet.. So I never know when the cyanide would be used up. If solid-liquid ratio is made to be more sensible like 1:2, then I probably need to add 0.6g of cyanide which I somehow feel it'll very soon used up.


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## sohwohn (Dec 31, 2017)

This is another run I tried earlier:
900g ore powders
2L tap water
30g cyanide (1.5%)
cyanidation 8 hours
pre-treatment with H2O2 4 hours and bleach 4 hours (I found this on a Chinese website but it didn't work)
carbon absorption 4 hours
10g AC used and .29g ashes recovered

Recovery rate was still 11.2% but I got Pd and Ag.

If I recall right, I got 4.9mg Au and .6mg Pd and .4mg Ag in .29g ashes. Fe was about 1.7% and I got Ti, Ni, Cu, Pb, Zn each lower than 1%


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## sohwohn (Dec 31, 2017)

anachronism said:


> Thanks for the extra info. My experience is related to ewaste and not mining so RenoChris and Deano will have a much more valid input than me.


We tried using cyanide to extract Pd in TWC and we got pretty good result.

2000g sample powders were used (Pd grade: 800ppm)
Bleach and H2O2 were added
It took 4 hours for pre-treatment and 11 hours for cyanidation. 24 hours for AC absorption.

40g AC used ad 1.2g ashes recovered. The 1.2g ashes got 61% Pd and very little Pt, no Rh.

So from 1.6g Pd we extracted 0.732g and recovery rate was around 45.75%.


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## Mezira (Feb 18, 2018)

Deano said:


> You have two possibilities for adsorbing gold values onto activated carbon.
> 
> The first is where you are adsorbing from a clean liquor with no fine solids present.
> 
> ...


mr deano is honorable .. on testing with this cyanide do we need to measure dissolved oxygen and its ORP meter ...
2. whether AC ash in aqua regia then in SNcl2 wear test


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## Deano (Feb 18, 2018)

I am assuming that you are referring to recovery of gold from the ash from activated carbon, you did not make this clear.

If you recover the gold from the ash with cyanide the simplest way is to make up a leach solution of 1 gram per litre sodium or potassium or calcium cyanide using a pH meter and caustic soda to have a pH around 11.

Stir the ash in the solution for a couple of hours and then filter.

The gold can be gotten from the liquor by electrowinning on to steel wool or by zincing. 

For small batches of ash you will not need to worry about D O levels, the action of stirring will keep enough oxygen in the liquor.

You do not need an ORP meter for cyanide leaching, just a pH meter.

If you are digesting the gold in the ash with aqua regia you simmer the mixture of ash and acid until the fumes turn from brown to white, takes around 30 minutes.

After cooling and filtering the gold can be precipitated from the clear liquor with the precipitant of your choice.

Usually the gold is settled over night and then filtered, there will be a very low level of gold residual in the liquor, usually less than a half ppm.

The cost of getting this residual gold is more than the gold is worth.

Deano


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## sohwohn (Feb 19, 2018)

Since it's been Chinese New Year recently, I did not have time to update my progress on this forum.

I went to the mining-site 2 weeks before CNY. The whole licensed-area takes about 0.88km².

There're some tunnels (deepest 300m) which consists mostly sulfides with Gold.

The highest Gold grade is about 300-400ppm (at 300m deep) and lowest is about 20-30ppm (at 100m deep).

Our team won't focus on the tunnels though.

We've found on top of the main vein there's oxidized Gold (around 3-7ppm).

The volume of this oxidized Gold is much larger than the main vein.

It takes lower costs (as well as lower risks) to process this low grade oxidized Gold than high grade Gold surrounded by sulfides.

Anyway, something here I need to clarify..

Before I head to the mine, I found that the chemical I was using wasn't actually Cyanide.

It was mainly composed by Thiourea (with some secret ingredients) and it 'only acts like' Cyanides.

Our people always call the process 'Cyanidation' but it's not actually Cyanidation.

I don't want to get people confused with my experimental results.

For reference, the chemical we're using is named 'Jinchan'.


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## sohwohn (Feb 19, 2018)

For more information about Jinchan, please wait for me collecting more data to make a conclusion.

By far, what I can tell is that it's more selective than Cyanides. The price is similar with NaCN and it consumes more. Though, the processed solution can be re-used by adding less Jinchan with much cheaper NH4HCO3. The overall cost is similar with Cyanides. Pollution-wise, Jinchan is much much more environmental-friendly and safe.

The effectiveness, as far as I have tested, can reach a little bit fast than Cyanides, while collecting above 97% Gold and around 50-60% Silver. If done with pre-treatments, it can also dissolve Pd with unknown effectiveness.

However, I have only done like 20-30 tests. I feel like not enough to optimise all the factors. So I cannot conclude 'how good' this Jinchan is. There must be pros and cons.

We will drive to the mining-site tomorrow, so I suppose I can make more experiments in the following 1-2 weeks. Eventually, I need to do the tests though. I am going to post the detailed collected data with conclusion about effectiveness using Jinchan, maybe in mid-March or late-March.


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## Eg.refiner (Jul 11, 2022)

sohwohn said:


> For more information about Jinchan, please wait for me collecting more data to make a conclusion.
> 
> By far, what I can tell is that it's more selective than Cyanides. The price is similar with NaCN and it consumes more. Though, the processed solution can be re-used by adding less Jinchan with much cheaper NH4HCO3. The overall cost is similar with Cyanides. Pollution-wise, Jinchan is much much more environmental-friendly and safe.
> 
> ...


Please i need more information about how to use the jinchan ( best EH ,PH for leaching gold ) and best PH for carbon adsorption ?


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