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Processing copper ores with high carbon shale (10 replies and 2 comments)
Have you considered a pre-float to remove the carbon?
For example, Kowalczuk, P.B., et al., IN SEARCH OF AN EFFICIENT FROTHER FOR PRE-FLOTATION OF CARBONACEOUS SHALE FROM THE KUPFERSCHIEFER STRATIFORM COPPER ORE, Physicochem. Probl. Miner. Process. 50(2), 2014, 835−840; or similar work?
A pre-float is the way to go as you will find it very difficult to depress. Off the top of my head I can't think of another copper plant with a carbon pre-float but Century zinc would be a good example. They have a pre-float rougher and cleaner circuit (to stop any entrained valuable from reporting to tails) ahead of their lead and zinc float. I believe the only reagent they add is a little frother. It would be easy to try in the lab to see if this could help your problem.
In the laboratory, we are developing pre-flotation tests with frothers aliphatic alcohol (MIBC) and glycol (1012).
MIM Cu Concentrator utilises a prefloat circuit to remove talc as well as carbon rimmed pyrite. The only reagent that is used is MIBC. After the prefloat circuit naphthalene sulfonate is used in the Cu float to control the carbon reporting to the final conc. I've also seen nigrosin used to suppress graphite on lead zinc ore.
Have been processing the copper-cobaltiferous ores with too much graphite (Carbon), talc at Gécamines/Katanga/DRC in the Katanga Southern Mining Company. These elements are pre-floated using only a frother (Dowfroth 250)
Based on your input, the best solution is to make pre-float to remove carbon with only frother and then to use a reagent for removing to copper?
To selectively float graphite alone is not that simple; depending on liberation etc. one may think of gravity to separate out graphite--I am not giving a final solution; I would like to get some laboratory tests before thinking of the machine/reagent etc.
The graphite removed with pre -float contains 1% Cu. in this case, is not applied pre-float, I am searched other alternative than makes this process feasible.
Have you tried increasing selectivity? Lowering the pulp level might help a bit. You could also investigate whether the carbon and copper bearing mineral are sufficiently liberated from one another. In a project I worked on previously, the carbon was intimately bound with pyrite, which made the prefloat doubly advantageous; it removed carbon and a large amount of pyrite too.
And hopefully the grain size it not ultra-fine to the point where carbon is smeared all over the key sulfides.
If you loose to my good sulfides, you can re-clean that (collector-free) using SMBS to knock down the sulfides and keep the C floating.
I worked on a few copper/lead/zinc deposits with high carbon content and used a blinder to block the carbon surfaces and obtain very good results.
100-300 g/t, 3- 5 minutes conditioning. The carbon grade in lead concentrate decreased from around 18% to 7% and lead grade over 50%.
I am processing copper ores with high carbon content (shale). The feature of the flotation foam large bubbles with high surface tension. I'm looking for a reagent that can help decrease the stability of the bubble, but that does not affect the recovery of copper and can prevent flotation of coal.