• To participate in the 911Metallurgist Forums, be sure to JOINLOGIN
  • Use Add New Topic to ask a New Question/Discussion about Flotation.
  • OR Select a Topic that Interests you.
  • Use Add Reply = to Reply/Participate in a Topic/Discussion (most frequent).
    Using Add Reply allows you to Attach Images or PDF files and provide a more complete input.
  • Use Add Comment = to comment on someone else’s Reply in an already active Topic/Discussion.

Recovering Moly from Copper Oxide and Sulfide (7 replies)

Maya Rothman
12 months ago
Maya Rothman 12 months ago

How can one recover molybdenum from both copper oxide and sulphide concentrates?

Tony Verdeschi
12 months ago
Tony Verdeschi 12 months ago

But is brief you have to regrind your copper sulfide concentrate to less than definite size such as d99 smaller -0.045 mm and then depress the copper sulfide and float the MoS2, one rare hydrophobic mineral.
There are a lot of details and technical notes in operation of the plants and also in engineering which is important to consider. I think the most challenge is chemical consumption to depress the copper, pH adjustment, H2S generation, final Mo concentrate grade, filtration of ultra-fine particles,
For example removing the collector reagents from surface of copper sulfide concentrate particles will help you to decrease depressant consumption.
Based on the environmental regulations, likely you are not allowable to use small amounts of the most effective depressant, NaCN, so you have to pay 10 times and more for other depressants.

Bill Fraser
12 months ago
Bill Fraser 12 months ago

Often it is going to depend on what you have done to the material in the bulk concentrator and what type of grinding and float circuit you have. Many people make the mistake of letting the molybdenum get overground un-necessarily, and this makes life harder later on. if this is the case you may not need to regrind. you really need to get good old fashioned mineralogy and mineral association done first. As Abbas indicates also surface chemistry is important. the use of Sulfuric acid in South america is normal to counter excessive reagent additions in bulk plants, but in North America is rarely used.

Another key issue is deposit variability. One moly plant designed for today is unlikely to be the same as the one for next year!

David Kano
12 months ago
David Kano 12 months ago

If the extraction of molybdenum did not occur in this part of the process, it is incorporated into the concentrate and recover in the casting after melting, and already forming part of the copper slag is currently economically impractical due to the reasons stated in the previous

* Copper-Molybdenum ores or molybdenite (MoS2) is predominantly molybdenum ore profitable. While it is naturally quite hydrophobic and can only effectively floated foaming, adding a petroleum hydrocarbon extension facilitates their recovery. It is necessary to make a concentrate of high purity molybdenum applications lubricants and oil additives so the challenge is to effectively remove all essentially the entire bargain and pyrite, which is a challenge, because the concentrations of mineral molybdenum are very low.

The molybdenum concentrate harder cleaned and cleaned again with corrections between stages to ensure maximum release. The flotation is conducted at high pH levels many times greater than 11 using lime to ensure good depression of sulphide minerals, particularly iron and copper sulphides. Other depressants include cyanide reagent used Nokes (or tioarsénico tiofosforoso components).

While there is significant molybdenum mining production, a significant amount is recovered as a byproduct molybdenum in copper mines. The flow chart is standard bulk flotation of copper sulphides and molybdenite during the depression of iron ore and gangue in the hardest circuits and cleaner.

The copper recovery is by standard flotation reagents identified in the description of the copper mineral flotation.

The naturally float molybdenum with copper but can be congested in the foam by the mineralization of copper and molybdenum collector use (such as diesel oil, kerosene, refined oils, pine oil or xanthate ester) improves its buoyancy. Additionally, since the pH optimum of float is 7-8 molybdenum optimum selectivity while copper is typically in a pH range of 9-11, the use of a flotation collector bulk molybdenum can improve buoyancy . Some mines are the collectors of molybdenum may have a negative impact on the flotation of copper should therefore carry out tests and evaluations to find the optimum hydrocarbon molybdenum collector and foaming products.

The separation and improved bulk molybdenite concentrate copper-molybdenite is generally carried out by molybdenite flotation followed by selective depression of copper and iron sulphides. Schemes standard depressants include high pH by adding lime, sodium hydrosulfide, Nokes reagent, etc. During the process of improving the molybdenum concentrate cleaner often is calcined to direct residual reactive of all minerals in the concentrate bulk Cu-Mo for selective separation easier.


Bob Mathias
12 months ago
Bob Mathias 12 months ago

After the initial depression of the copper and iron minerals, frequently it is necessary to have one or more cleaning steps to upgrade the Molybdenum concentrate to a salable quality. Cleaner flotation alone seldom accomplishes this, particular if a hydrocarbon either used as a collector or tramp oil from mining operations is present. Molybdenum will form small balls of mineral called Cattermoles. These mineral balls have to be broken up to release entrained gangue and unwanted sulfide minerals. This is best done in mills that use flint pebbles or ceramic balls. The Climax mine in America used up to five stages of regrind/flotation to achieve 99.4% MoS2 concentrate for chemical applications. The first three stages used tube mills with flint pebbles to make metallurgical grade concentrate and two more regular profile ball mills loaded with aluminum oxide fused balls for lubricant and chemical products. Iron balls were not used because the wear particles were carried along in the concentrate. Sodium Cyanide was used as a depressant in very low concentrations.

Paul Morrow
12 months ago
Paul Morrow 12 months ago

The most depressant reagent used in SouthAmerica is NaHS (around 95%), other depressant is a blend of Na2S with As2O3 (but is dangerous for the As content) and the other is Nokes reagent. The Moly flotation pH ranging is betwwen 7-9. The dossage of depressant that you normally has are approx 4 kg/ bulk concentrate. The flotation ORP normally is from - 500 mV to - 600 mV, depending of the Copper Sulphide species. Depending of the pH you will have H2S gas emmision to the ambient that you can have controlled in float cells closed and with scrubbers with caustic solution (10%) achieving in some cases close to approx 0 ppm of H2S to the plant site ambient.

A problem that has the NaHS is the fast oxidation kinetic and for these the ambient in the flotation needs to be with inert gas ambient, with N2 or rare aire (very poor in O2). This you can achieve with N2 plant or with Inertgas float cell (self-aspirant their own rare air)

Victor Bergman
12 months ago
Victor Bergman 12 months ago

Can you give me more information on the Mo-cleaning stages? I know column cells are preferably used in the second, third and fourth stages of cleaning (if there are this many stages of cleaning to start with). There is not a lot of information out there as to how Mo column cleaning cells perform.

Bob Mathias
12 months ago
Bob Mathias 12 months ago

The economies of the process must be considered in parallel with the chemical/mineralogical aspects. Frequently, making a very high grade concentrate is counterproductive. It is mentioned in several of the other comments here that some reagent cost are very high particularly if they are not produced in the local area.

If the molybdenum is a significant value in the ore, and reagent and capital cost are high, a quick study of sequential flotation of moly then copper without use of large amounts of collectors and depressants would be warranted.

Typically two or three stages of cleaning re-cleaning will be enough to make a metallurgical grade molybdenum concentrate. In my experience the use of column cells are little better than standard cells. The efficiency of the process is determined more by the breaking of the small mineral agglomerates than the type of equipment.

Please join and login to participate and leave a comment.