Hydrometallurgy: Leaching in Heap, Vat, CIL, CIP, Merrill–Crowe, SX Solvent Extraction

Hydrometallurgy: Leaching in Heap, Vat, CIL, CIP, Merrill–Crowe, SX Solvent Extraction

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Started by PEKYEEPE
Am supervising a CIP circuit with 6 adsorption tanks. Due problems in the trash screen, the grits (coarse sand > 800 micron) are retained in the tanks. Our aim is to use knelson concentrator for the separation of grits and activated carbon. In th...
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Last replied to by rob riggir
The best method, which I have used, is a Denver-type jig. Works a treat!!
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Started by Oberstorm
Any idea to maintain pH on leaching tank that is relatively high (chemical reagent added will not give negative effect on leaching performance)?Our plant is having problem with high pH of leaching. Based on our lab test, optimum pH is on range 10.3-1...
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Last replied to by Amaila Tahir
why pH increased during leaching of copper take place from waste materials? why redox potential decreased when pH of the reaction medium increased during leaching of copper ?
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Started by emanus
hello metallurgist; please, what is the function of iron (Fe) in gold leaching process with thiocyanate as a Gold Dressing Agent composition?  
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Last replied to by Unterstarm
Thiocyanate as a leaching agent for gold has been studied by many. The overall reaction for gold dissolution by thiocyanate can be written as: Au + 2SCN- + Fe+3 ⇔ Au(SCN)2- + Fe+2....................
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Started by Tarun Karakoti
What is the minimum size of ore in gold heap leach? Without problem of percolation!
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Last replied to by Nurettin
  minimim size depends on screening quality and stacking homogeneity and partical shape. if you have a bad size distribution percolation will increase but leaching quality will decrease.  if you ...
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Started by Nyasha Jawanda
Hi, I would like to know ways in which i can increase gold leaching efficiency and percolation rate in heap leaching using cyanide?  
Last commented on by David
how to increase heap leaching efficiency
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Started by Mikhail
Who knows about the cyanide reagent substitute Flotent Gold SC 570? I have a substitute cyanide. Flotent gold SC 570. Anyone doing research on leaching with its use? I have a problem with the definition of its solution. The technique is said that he...
Last commented on by Mikhail
Вы можете связаться со мной по электронной почте pinyasov.estageo@mail.ru
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Started by kenyaAurefiner
Hi everyone. Recently my friend and I came across some 30 year old tailings - about 1000 tons - which was analyzed to contain mainly 0.002% gold and 3.35% ferrous materials. I have no experience in gold processing, but my friend has some. He seems to...
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Last commented on by labalkeny
hello all. What about the option of using hypo chloride or thiosulphate to leach what ever concentrate he would have come up with. can any body shed some light on the two suggested processes"
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Started by Charlie
What is the typical % solids you would generally run a CIL circuit at? Thicker will result in more retention time but does it leach gold or silver as effectively? Any negative impact on carbon? Thanks
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Last commented on by Ahmed
I am working with an average of 42% solids, and we are facing a problem of carbon settlement in the bottom of the tanks. what are the other factors that can cause this problem
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Started by Nyasha Jawanda
hello guys...im a metallurgy student currently attached at a heap leach practicing company mining oxide ores(low grade ores).we use cyanide for the leaching process and carbon in the adsorption section..we are currently experiencing  low recoveries ...
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Last replied to by ThabisoKwenane
Check if your cyanide distribution into the heap is even. Also check your particle size distribution. You don't want to have the same size of particles throughout your heap. A varying distribution wil...
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Started by Kumar Choudhry
I want to know if anyone has an idea or a resource book on how to conduct and interpret the results of preg-robbing test in both CIP and CIL. Also wants to know if the PRIs are good indicators of preg-robbers in ores associated with carbonaceous mate...
Last replied to by Charlie
Carbon is added at the initiation of the leach period to determine if preg-robbing constituents were present in the material. In the leach tests, if the gold extractions from the direct leach and the...
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Started by Nathan
Hello All, I work in a CIL plant, processing oxide ore with more and more intrusion of sulphides (fresh ore body). The plant is designed for oxide ore but we noticed that at a certain blending, the transitional ore could be processed. It impacted on ...
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Last commented on by Paul Lingei
Where is the best location to add oxygen (from hydrogen peroxide)? Can it be added at the head of leach tanks? Or into leach tanks?
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Started by Arnmax
Currently in our gold plant we are getting a huge change in activated carbon in circuit inventory  during opening and closing stock from time to time. Now I have been given a project on carbon movement study in which I will investigate possible ways...
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Last replied to by Jorge
It is well known that active carbon is lost by attrition and abrasion during the adsorption process, and also when is pumped, transported, screened, burned and regenerated. Abrasion tests involve sub...
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Started by ramine
i am student and work in geometallurgical modelling in heap leaching of cu ... can you help me and give me your idea?
Last replied to by
Thanks Jorge. Hello ramine read and be sure to understand all of https://www.911metallurgist.com/blog/geometallurgy-course
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Started by Gombera
Dear Professionals, what are important steps should I follow when I want to design copper agitated leach tanks? Cheers, Heri
Last replied to by Marshal Meru
Also see https://www.911metallurgist.com/blog/metallurgical-testing-lpf-process  https://www.911metallurgist.com/blog/copper-lpf-leach-precipitation-flotation-process https://www.911metallurgist.c...
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Started by Helena Russell
Conditioning of an ore pulp is understood to mean its preparation for subsequent treatment by cyanidation or by flotation. Is it real an important step? How do you best go about it? How long?
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Last replied to by CHIKWAMO
f your feed throughput to the leach agitation tanks is 2500 tpd (104 t/hr) and the ore feed is @ S.G of 2.6, how do you work out your required thickener volumes downstream?  
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Started by Greg OConnor
Hi all, I have a very simple question for which I am having trouble to find an answer. Can anyone direct me to studies which compare the leach rates of chalcopyrite with other copper minerals - particularly sulfides? There seems to be plenty on cy...
Last replied to by David
Hi  Greg, I am waiting on input from a friend on this. From now this may guide you a bit: https://www.911metallurgist.com/blog/acid-solubility-copper-mineral-species  
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Started by kahonde
kindly asking what are the factors affecting activated carbon adsorptivity? does cyanide strength affect  carbon adsorption and if so, what concentration?
Last replied to by Bob Mathias
The major physical factors affecting gold adsorption onto carbon are: Carbon type Carbon particle size Mixing efficiency Slurry density Temperature Gold concentration in solution Cyanide...
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Started by max skinner
I would like to separate zinc from manganese out of a 20%  sulfuric acid leach solution, any ideas? 
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Last commented on by Bhaduri
Try 28% ammonia...sufficient to neutralize acid, precipitate Mn as an aqua hydrate & solubilize Zn as the tetraamine complex...
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Started by
Can you cyanide leach gold when oxide copper CuOx is contained to an approximative 0.3% Cu and Au is 10 g/t?
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Last replied to by Colette
Bill Copper oxides normally leach pretty well in cyanide solutions - you can see how well here https://publications.csiro.au/rpr/download?pid=csiro:EP112080&dsid=DS2 You are definitely in the "it's...
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Started by Seeker
For gold dissolution in Sodium Thiosulfate solution, I have to add FeEDTA at a concentration of 0.002 mole/L. I have with me Ferric sulfate and EDTA (Ethylenediaminetetraacetic acid) separately. Please advise me how many grams of ferric sulfate and E...
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Last commented on by Seeker
Thanks a lot for your advice. Could you please suggest a simpler way for this?
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Started by Nyasha Jawanda
Hi What are the metallurgical issues considered when planning the construction of a heap leach for gold in oxide ores.
Last replied to by David
Hi Nyasha and Welcome, to complement to Jorge's comment, please see: http://technology.infomine.com/reviews/heapleachpads/welcome.asp?view=full and https://www.911metallurgist.com/blog/heap-leach...
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Started by max skinner
What cubic foot per minute vacuum pump is needed to deaerate a 10 cubic foot tank to 20 inches of Hg with a flow rate of 50 gallons per minute.  
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Last commented on by max skinner
Thank you, I will try 30-35 cfm
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Started by Seeker
Kindly explain following points about gold leaching with thiosulphate from gold plated processors What is the ratio of acid to acidify the solution for gold leaching with sodium thiosulphate? Which acid is best to acidify the solution? What compound...
Last replied to by
Hi Seeker and welcome, have you seen https://www.911metallurgist.com/blog/sodium-thiosulphate-gold-leaching
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Started by tihisha sabur
Our plant is gold processing plant contains a ball mill and knelson gravity concentrator , pre-leach thickener .CIL, CCD. For time being our gravity concentrator is not working. . 1. which is more precise the ball mill feed or leach feed (pre-leach ...
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Last replied to by Jorge
About your questions, I can say that the ball mill fresh feed should be considered to determine gold feed grade to the leaching process. If you want to evaluate the CCD circuit, you should take sample...
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Started by New Era
my problem is we don't have tailing and concentrate at same time , we feed solid gold to the leach tank , i can calculate how much gold i have leached , this does not include the amount of gold lose in solution form . now i am using this formula ...
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Last replied to by Bhaduri
Sometimes it is easier to explain concepts thru' a worked problem...let me know if the appended example makes sense in attempting to answer your query.
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Started by Mikhail
What do you think is necessary to conduct tests CIP / CIL process ? What information would be most useful for the results of laboratory experiments? As in the laboratory to simulate a continuous process of CIP?
Last replied to by David
Hello and welcome Mikhail. Thanks for your great input Jorge. Mikhail, you may want to also review: Cyanide Bottle Roll Leach Test – Leaching Procedures Cyanide Gold Extraction Process ...
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Started by Sudhirkumar
We ran a milling in cyanide CIL plant for reprocessing a gold tailings dump for one and half years. We were achieving 60-70% dissolution in the mill then followed by adsorption in 6 CIL tanks.We are now looking at modifying the process and introducin...
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Last commented on by Colette
You can use floc and coagulants with lamellas, and as with the use of any thickener ahead of a carbon process - the organics will adsorb onto your carbon, but usually nothing that a normal regen proce...
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Started by Maya Rothman
I was wondering if anyone has had experience in heap leaching of gold ores with sulfur content ( 0.1 to 1 percent)Some suggestions for pretreatment or treatment of such ores by heap leaching process.
Last replied to by
The best recommended method is CIL/CIP to recovery gold in a sulphide ore and you must design condition tanks for per treatment of sulfur, in this condition tanks you must dose lime of at least 12 pH,...
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Started by Rahil Khan
What effect do flotation reagents have on activated carbon during gold adsorption? Do they have an effect or not? If yes, then what effect do they have?
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Last replied to by Sturmbann
Search for work done in the mid to late 80's by AMIRA in Australia, they did a mountain of work on all the different types of fouling agents for carbon, including all types of flotation collector, fro...
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Started by
To all you clever Gold Metallurgists, which carbon does you prefer to use, Indian supply or Philippine supply (Coconut shell).Both countries sell Coconut shell carbon, getting a supplier that has tested their carbon to ATSM standard is the cruncher. ...
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Last replied to by Obergruppenfuhrer
The source of the carbon is probably not as important as the quality control in the manufacturing process to produce a product with a decent balance of hardness, porosity and size distribution. In my ...
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Started by Sachin Prakash
We are having a problem of carbon floating in one of our CIL tanks. Does anyone know what causes that and how it can be rectified?
Last replied to by Tarun Karakoti
Considering all the contributions given, as rightly said, the problem is with that particular tank (Tk 04). First check and parameters like the current drawn by that agitator motor, agitator gearbox s...
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Started by Rahil Khan
I want the best technique to recycle the cyanide from tank#8 to tank#1. Which now we add 300ppm cyanide in tank#1 and we get 180ppm in tank#8 (tailing).
Last replied to by Sudhirkumar
I would suggest to you to follow what has said about splitting the cyanide addition on the 3 first CIL tanks. If the goal is not reached, I suggest to you to start looking at the thickening option to ...
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Started by Sudhirkumar
On the CIL processing of free milling oxide gold ore, how far I can drop the free cyanide concentration in the leach tank#1? In order to minimize the cyanide consumption without any impact on gold recovery! Currently our practice in the 1st leach tan...
Last replied to by Sachin Prakash
First I must say you are one of the fortunate people to still be treating such forgiving ore. The cost of cyanide prompts for urgent and efficient ways to significantly bring down its consumption with...
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Started by Maya Rothman
I would like to know if anyone has ideas on how to reduce settling of materials in leaching tanks. The plant is a gold production plant and the ore treated are oxide and fresh rock.
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Last replied to by Sturmbann
There are two factors that you need to balance, the settling rate, which is a factor of pulp density and rheology, and the lift from the agitator.http://is.gd/raVkGnThis may help you understand. I sug...
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Started by Rahil Khan
ILR pregnant solution is expected to contain much impurity than the CIL or CIP pregnant solution for electrowining. This may be due to the intensive leach conditions in the ILR than in the CIL or CIP.I want to know which process contributes to lesser...
Last replied to by Oberfuhrer
You will have fineness of bullion produced by intensive leach much higher than from CIL.

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