Laboratory Testing & General Mineral Processing Engineering

Laboratory Testing & General Mineral Processing Engineering 2017-03-23T09:50:31+00:00
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CIP and CIL Testing (8 replies)

Victor Bergman
1 year ago
Victor Bergman 1 year ago

I have done cyanidation tests on concentrates. In the beginning I did pregrrobing test, to determine the optimal size of a concentrate for gold recovery. After these tests, others were conducted to determine the time of cyanidation. Then, a test to determine the optimum parameters of solids in pulp.

I do not have a continuous plant for cyanidation (cascade) There is only an agitator with air. Bottle tests. I am interested in a detailed test CIP and CIL. I can identify the leaching kinetics for both processes. What remains to be investigated?

Maya Rothman
1 year ago
Maya Rothman 1 year ago

Both are simple tests. There are a couple things to remember. Grind size of the ore verses the size of the carbon. Agitation has to be done by air not with mechanical agitation. Mechanical agitation causes the carbon to break down and you end up with large losses in recovered values back into the ore. High density coconut carbon is the preferred carbon to use. Ore should be ground to 200- to get good results. The carbon should be rinsed with distilled water to remove all fines. It is best run with Cyanide or thio-sulphate or other alkaline leach's. In acid leaches large amounts of base metal are also absorbed into the carbon. 

JohnnyD
1 year ago
JohnnyD 1 year ago

Also refer to the pioneering lab scale work (references below) conducted by the South Africans during the mid-80's; the objective in a nutshell is a) if the ore is clean (no cyanicides/preg robbers), a simple grind-classification-leach-clarification-CIC circuit is justifiable w/CIP as a scavenger at the tail end...C & locked-up Au inventory may be significantly reduced or b) if the ore is mildly refractory (carbonaceous), CIL in lieu of CIP may be required following grinding-classification to negate preg robbing aspects.

Nicol, M.J., Fleming, C.A. and Cromberge, G., 1984, The absorption of gold cyanide onto activated carbon. I. The kinetics of absorption from pulps. J. S. Afr. Inst. Min. Metall., Vol. 84, No. 2, 50–54.
Nicol, M.J., Fleming, C.A. and Cromberge, G., 1984, The absorption of gold cyanide onto activated carbon. II. Application of the kinetic model to multistage absorption circuits. J. S. Afr. Inst. Min. Metall., Vol. 84, No. 3, 70–78.
Fleming, C.A. and Nicol, M.J., 1984, The absorption of gold cyanide onto activated carbon. III. Factors Influencing the Rate of Loading and the Equilibrium Capacity. J. S. Afr. Inst. Min. Metall., Vol. 84, No. 4, 85–93.

Maya Rothman
1 year ago
Maya Rothman 1 year ago

Suggest you determine first what forms of gold you are dealing with. Using electron scanning microscope (ESM) you can determine what forms of gold are present in the head ore sample. Many forms of gold are not recovered by gravity nor by cyanide. I would suggest if your gold is metallic and you can make a gravity concentrate you check your recovery against loss. The other test would be time verses temperature and cyanide consumption.

Victor Bergman
1 year ago
Victor Bergman 1 year ago

I have complete information about the concentrates. mineral and chemical composition. There is full information from an electron microscope. I have been working with a mixture of gravity concentrate (yield 0.7% with a gold content of 40 g / t gold have a large particle size of 0.02 mm) and the flotation concentrate (yield is about 4.5% of the gold content of 20 g / t) . This concentrate is processed together. First tests showed recovery of 92 to 96%.

Victor Bergman
1 year ago
Victor Bergman 1 year ago

Also, the difficulty is how to conduct the test on the kinetics of sorption. If I take 1-2 ml of carbon and will leach 200 g of concentrate, then all the gold is absorbed instantly. I have no great weight of the concentrate, what to do?

Alan Carter
1 year ago
Alan Carter 1 year ago

If I understand you correctly you simply want to carry out CIL vs CIP tests? That means, aside all issues related to the refractoriness, mineralogy, etc. etc. have been understood. That also means, you may have carried out flotation (or another concentration method-such as gravity to end up with what you have and you want to do CIP/CIL tests)? Generally in CIL tests we add carbon in the test vessel after certain period of time (depends on your ore, or cyanidation conditions, for example as lime pre-conditioning). Many people insist CIL/CIP tests must be done in agitated leach vessels. On the other hand many others claim bottle rolls deliver better results. My preference is bottle rolls. In fact there is a good paper, which will be presented right on this subject in the upcoming Mill Operators Conference in Sep 2015 in Perth (I have to clarify I am not the author of this paper. Check the web site you will find out the details, and also might ask from the author for a copy of the paper).

The issue with your test conditions (200 g at high grade) is that you cannot use large enough bottle roll as the pulp density will be too low. You might also find that you will need to use a very high free cyanide concentration in your bottle roll. When you add such a small amount of carbon and all gold is adsorbed, it is not surprising. But when do you add carbon? After what time period (for example 4 hr, 12 hr, 24 hr). Why do you need to add carbon at all? Because the concentrate still has pre-robbers, or other? Did you find that adding carbon during leaching increase recovery? If not you may not need to add any carbon at all during leaching, and conduct adsorption tests on the solution after the leaching is complete. Also why do you need to mix coarse gravity concentrate and fine flotation concentrate? 

Victor Bergman
1 year ago
Victor Bergman 1 year ago

I really need to understand how to conduct tests in the laboratory CIP or CIL. I would like to know the methodology of these tests for different types of concentrates.

As far as my concentrate. 1. I mixed it several reasons. Firstly, it contains a small size gold (0.02 mm). Second, it contains about 40 grams of gold / ton. In the third of his output is very low (0.78%) and it is diluted in the flotation concentrate. To all above can add and test results for cyanidation. Gold recovery from gravity and flotation concentrate in 8 hours is 92-96%.

Bob Mathias
1 year ago
Bob Mathias 1 year ago

It's seems that you possibly do not have enough CN for leaching high grade or residence time is not enough for the nugget Au grains. CIL tests are done when you have prep robbers, carbon is added at start of leach, CIP is when carbon is added near the end of the leach.

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