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 EAKUVI
What causes high Barren eluate
Last replied to by SmartDog
Many things. Process design, process operational upsets, improper chemical addition, wrong chemicals, poor maintenance, bad lab work, water quality changes, bird droppings, people using the process a...
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67
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Started by Sheila reid
Trying to find out the effectiveness of using a tube retort for recovering gold from mercury amalgam.The link below shows an image. Im also having problems finding one to purchase https://imgur.com/a/xEGyR1y
J
Last replied to by Jorge
Follow the link below, https://www.911metallurgist.com/blog/mercury-retorting
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63
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Started by Nasirali111
I have gold ore which I finely grinded to powder form. I then added aqua regia in it and let it complete the digestion process. Afterwards I filtered this solution twice to get absolutely clear liquid. I then added caustic soda in excess In it and le...
J
Last replied to by Jorge
Follow the links below,
Laboratory Testing & General Mineral Processing Engineering
Gold Refining Process by Aqua Regia
 
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90
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Started by Eng. Cosmas Wambura
Ammonium Nitrate is among of chemicals used to control copper in gold vat leaching, so I wish to know how to use it. The capacity of a single tank is 40t. 
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Last replied to by Jorge
The addition of ammonium in the cyanidation of a gold ore containing soluble copper to reduce the effect of copper has been practiced for many years in some operations. It has been found that the addi...
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494
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Started by Eng. Cosmas Wambura
Hello Friends, some one help me the way to obtain the tonnage of round vat tank; As i know; Vol. = (pi*D²*Height)/4 To obtain mass , i use Density = mass/volume Now; if this formula is correct, what is the density of raw ore? Else; if it`s not...
C
Last commented on by Eng. Cosmas Wambura
How can I achieve this?
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242
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Started by ecublens
Hello, there is some arsenic in an oxidized gold ore analysis. It is not in the form of arsenopyrite. I thought it was acting with antimony, but the Sb content is also very low. Could you give an idea what the arsenic here might be acting with?
C
Last commented on by Eng. Cosmas Wambura
Can these arsenic minerals affect the recovery of gold?
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63
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Started by GylcineLeacher
Processing of gold/silver tellurides is well documented in operations such as Emperor Mine in Fiji, Kalgoolie in Australia and Cripple Creek in Colorado, USA. Although all of these operations initially utilized roasting, in today’s world it certain...
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425
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Started by OGUZTURE
Hello dear friends, Proffessors We have a factory that recovers precious metals from electronic waste. Here we first shred the motherboards of electronic scraps. And we separate the parts. We throw the precious metals in a furnace and melt them. We ...
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Last replied to by Scotman
Hi Oguzture One can also use a less "vicious" acid than Nitric. Thereafter, selective recovery is possible, which can give you the metals without any tin present. Regards Scotman
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642
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Started by Eng. Cosmas Wambura
Controlling Copper is a big problem at my site, so I need help on which reagent can I use in the cyanidation of gold. Which reagent can I apply to control Copper in old vat leaching?
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Last commented on by Scotman
Did you find a process? Have you looked at alternative leach and recovery methods.RegardsScotman
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247
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Started by Timey
I would like to recover Barium, Scandium, Strontium, Lanthanum, Yttrium, Vanadium from the same ore heap. Please advise on the best process, or help with flowsheet diagrams and materials. Thanks
T
Last replied to by Scotman
Hi Timey. Did you manage to come across a process? 
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75
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Started by John KK
In six months, we are going to start getting gold ore from underground mining which is an extension of open-cast mining. There was no metallurgical test conducted on the variability of the ore that is planned to feed to the Process Plant on the assum...
Last replied to by SmartDog
Since you are posting in the hydrometallurgy section an assumption would be that your process is hydrometallurgical, if not what is it? Going frpom that point, a key difference will be ore grade.  M...
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357
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Started by idahalen
I am currently researching Nickel hydrometallurgy and I am looking to understand the hazards on a HPAL circuit, specifically the Fleaters and Autoclaves.  I understand that under certain conditions autoclaves can explode but I do not see how this ca...
Last replied to by idahalen
belated thanks SmartDog.  I guess the hint is the presence of safety valves.  I have modelled a deflagration at operating pressures at varying free-volumes - quite significant collateral damage.  T...
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100
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Started by EAKUVI
Does carbon sink in the tanks with increasing densities or decreasing densities 
Last replied to by SmartDog
Normally the tanks are agitated to keep everything in suspension and well mixed. So relative settling is not an issue. If the agitation is stopped, everything will sink with large heavy particles sin...
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400
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Started by Anudari
Hello all, I am working as a metallurgist first time after graduation in Gold processing company. But I have learned that this processing plant has many issues that needs to be solved immediately. Because the plant does not have waste pond or someth...
A
Last replied to by Anudari
Update on the topic. I have solved the issue. Just like Jorge said, I had to increase the concentration of HCL and lower calcium amount in the activated carbon. I am not sure what was the most influen...
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212
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Started by WTandC
What would be the expected micron size range of carbon fines in a CIL circuit?  
B
Last commented on by WTandC
Thanks Jorge. Would a technology capable of recovering >25 micron size without using chemicals have value in a carbon fines recovery circuit?
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361
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Started by WTandC
I have read the leach emitters can be subject to clogging from recirculating suspended solids. Would removing all suspended solids >1 micron be a significant improvement for the leaching circuit?
B
Last commented on by WTandC
Thanks Jorge. My apology for taking so long to reply.
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198
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Started by John KK
Hello everyone We are running CIL tanks with under-designed impellers, and we are struggling to keep the material suspended. To help the agitation we are pumping high airflow through the shaft, but the result is not promising. Does the airflow help ...
P
Last replied to by pz
Adimulu, also note that a too high air flow under the agitator could and will lead to the agitator's flooding when air is basically preventing blades from moving the liquid. So increasing the airflow ...
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223
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Started by Rutendo Praise
I have a few tons of china clay, and a sample showed good results, but then the clay is fine and may give me problems processing it. Is heap leaching the best way to have the highest recovery?
R
Last commented on by Rutendo Praise
Thank you
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237
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Started by Ajouhi
We operate a CIL plant (8000 t/d), we recover fine carbon after elution and regeneration. I am concerned that the fine carbon recovered after screening the regenerated carbon has a higher grade (1000 ppm) compared to the eluted sterile carbon (100 pp...
J
Last replied to by Jorge
It is well known that most of the gold absorbed by activated carbon can be removed during elution. But it is also possible that the carbon has the Ca(Au(CN)2)2 complex present, which can be partially ...
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404
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Started by koki
when harvesting silver from silver cell it looks like semi muddy not solid crystals, what might be possible reasons for this
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242
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Started by Metallurgystudent
Good day to all! Please provide a hand.   What is the most secure way to separate iridium from osmium metal?
A
Last commented on by Metallurgystudent
Thanks a lot for your help.
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278
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Started by simon@p
Hello. There is a batch agitation tank that we are operating as a pilot for our ore. The  problem is that we have been getting a problem of inconsistence in carbon results as they may reach example 380 Au ppm then later on with a good recovery fro...
J
Last replied to by Jorge
It is important to know the gold extraction from bottle roll tests. Sometimes, tests are not performed correctly and some factors such as the presence of small contents of pre-robbers is not evaluated...
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257
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Started by canerdogan
Hi, How to i know the ore is calcined or not at the roasting stage before heap leach process. 
J
Last replied to by Jorge
Roasting is considered a pre-treatment before Carbon-in-Leach Process to treat a refractory gold ore. It is necessary to perform a testing program to determine the effect of particle size (e.g. 70, 50...
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260
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Started by ecublens
Hello, How can we calculate the amount of cyanide (g) that needs to be added after titration in the bottle roll test? 
J
Last replied to by Jorge
As you know the volume of leaching solution, you can know the NaCN added initially. For example, NaCN addition 1 g/L, and the volume was 500 mL. In this case you added 0.5 g of NaCN. The titration pr...
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304
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Started by ecublens
Hello, I need a procedure that explains how to do the cyanide column leach test in detail. I would appreciate it if you could share it with me.
Last replied to by SmartDog
A quick search of this site (outside the forum area) will provide most of the test procedures you are looking for, such as https://www.911metallurgist.com/blog/column-leaching-procedure
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513
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Started by pz
Hi everyone. I wonder how is oxidizing gas (O2/air) flow rate is calculated for the atmospheric cyanide leach. I have experience with pressure oxidation of sulfides. The calculation method is very straightforward. First – calculate stoichiometric ...
Last commented on by SmartDog
Depends on tank size, particle size, solids concentration, agitator size, agitator blad configuration, and agitator transmission/belting. Also wether you are trying for high shear or low shear mixing...
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357
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Started by saeidar
Hi everyone. I want to remove Strontium from barite ore. I would appreciate if you help me in this regard.
W
Last replied to by Wieslaw Wodecki
Dzień dobry. Jaki minerał tworzy Sr w tym barycie i ile go tam jest. Pozdrawiam Wiesław 
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6502
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Started by simon@p
I would like to ask about the state of gold in eluant and it's chemical formula if any
J
Last replied to by Jorge
Basically, the elution or stripping of activated carbon is performed to get a high-grade gold cyanide solution (eluate), which is treated by electrowinning or some cases by cementation. During the elu...
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412
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Started by graeme23miller
i am looking for anyone with experience in selecting materials of construction in high concentration chloride brine.  we are doing a class 5 feasibility study without any corrosion test work. as a result the selection of materials are generally non-...
Last replied to by SmartDog
Some of it comes around to the volume of material you will be handling on a hourly and daily basis.  There are some ootb thoughts that can be used if proper care and thought is used.  First though j...
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461
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Started by ManUtd67
What are the best options to prevent build up of sticky material in a drum agglomerator.  This is an acid agglomerator.  Build-up of a ring of material occurs part way down the agglomerator between the acid spray pipe and the water spray pipe. (See...
G
Last replied to by graeme23miller
from the look of your agglomerator the water addition is too high=> very sticky materials and build up. this is due to the moisture addition being at or even slightly above the material max stickin...
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411
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Started by ecublens
Hi guys, what is the difference between activated carbon adsorption and zinc cementation (merrill crowe)? How are these methods selected in a newly established gold enrichment facility? Thank you  
J
Last replied to by Jorge
Follow the links below to get information on activated carbon and zinc cementation, https://www.911metallurgist.com/blog/gold-cil-process-explained https://www.911metallurgist.com/equipment/...
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434
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Started by Austin Muvimi
Hi guys. May you please school me on how to culculate the optimum mechanical agitator rotation speed in gold CIP plants taking into consideration the tank size and pulp density   Thanks in advance
Last replied to by SmartDog
The normal process is to use the coarsest particle size expected and then determining the minimal settling velocity for that size given the pulp specific gravity and partical specifc gravity.  This g...
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620
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Started by CharlieAlAfensh
There is a solution that contains sodium chloride and potassium chloride, and we want to dissolve the largest possible amount of potassium chloride in the solution
J
Last replied to by Jorge
If you try to smelt the concentrate, the dore bar would content gold and base metals. The gold grade has an impact on the dore bar quality. You should study carefullly the content of base metals in th...
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415
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Started by awunderl
Looking for any resources or research on chalcopyrite leaching for recovery vs particle size.  Looking to see the effect of different particle size distributions on a copper recovery curve for run of mine material.  Focusing on larger size fraction...
J
Last replied to by Jorge
The application of chalcopyrite leaching has been studied for a long time, but the economy and metallurgy performance are complex. For example, the effect of particle size on copper extraction in sulp...
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459
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Started by Crisady
Can you tank gold amalgamation tailings straight to the regrind and the to cip without passing through vat leach and still achieve the same recovery.Iam just brainstorming on ways to cut costs without losing my gold.Can someone assist from experience...
J
Last replied to by Jorge
You can repulp and leach the tailings from amalgamation process. Artisanal miners are used to use mercury to recovery free. Tailings from this process are sold to cyanidation plants designed to operat...

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