Molybdenum Ore Beneficiation Methods

Molybdenum ore beneficiation method is mainly flotation, the recovered molybdenum mineral is pyromolybdenite. Sometimes, in order to improve the quality of molybdenum concentrate and remove impurities, the molybdenum concentrate is then subjected to chemical beneficiation externally.

Pyromolybdenite crystals are hexagonal layers or plates, formed by the S-Mo-S structure along the interlayer van der Kijen and the intralayer polar covalent bond S-Mo. The interlayer bonding is very weak, while the covalent bonding within the layers is very strong. Therefore, molybdenite is very easy to be produced in the form of sheet or plate along the structural interlayer cracking, which is the reason for the good natural floatability of pyromorphite. Practice has proved that: in the appropriate grinding fineness, molybdenite crystal dissociation occurs in the S-Mo-S interlayer, hydrophilic S-Mo surface accounts for a small proportion. However, when overgrinding, the proportion of S-Mo surface increases, and the floatability decreases, although at this time, adding a certain amount of polar trapping agent such as yellow drugs, which is conducive to the recovery of molybdenum pyroxene, but overgrinding produces a new sludge affecting the effect of flotation. Therefore, the separation of molybdenum pyroxene to avoid and prevent over-grinding, in the production of the need to use segmented grinding and multi-segment separation process, and gradually reach the monomer dissociation, to ensure the high recovery of molybdenum concentrate.

The crushing of molybdenum ore generally adopts a three-stage and one closed-circuit process, and the size of the crushed final product is 12-15 mm.

Grinding is typically done in a ball mill or rod-ball mill process. Henderson is the only one that uses a semi-autogenous grinding process. Flotation is by preferential flotation. Roughing produces a molybdenum crude concentrate, and the rough sweep tailings are either recovered for associated minerals or discarded. The molybdenum rougher concentrate is regrinded in two or three stages, with four or five concentrates to obtain the final molybdenum concentrate.

The flotation chemicals for molybdenum ore are non-polar oils as trapping agents, with the addition of a foaming agent. The United States and Canada use the surfactant Syntex as the oil emulsifier. According to the nature of the ore, lime is used as an adjusting agent, water glass is used as a vein inhibitor, and sometimes cyanide or sulfide is added to inhibit other heavy metal minerals.

In order to ensure the quality of molybdenum concentrate, molybdenum concentrate contains copper, lead, iron and other heavy metal minerals and calcium oxide and carbonaceous minerals need to be further separated: generally use sodium sulfide or sodium hydrosulfide, cyanide or ferrocyanide system of copper and iron; with dichromate or Nokes (Nokes) inhibition of lead. If the use of inhibitors, the impurity content is not up to quality standards, still need to be supplemented with chemical beneficiation: secondary copper sulfide leaching with cyanide; chalcopyrite leaching with ferric chloride solution; galena leaching with hydrochloric acid and ferric chloride solution, can reach the standard content.

Calcium oxide-containing veinstones are easy to sludge, so do not over-grind for ores containing such veinstones. Production often add water glass, sodium hexametaphosphate or organic gum as a chondrite inhibitor or dispersant; can also be used with activated carbon and CMC (carboxymethyl cellulose) to inhibit carbonate chondrites. Eventually, it can be treated by leaching with hydrochloric acid or hydrochloric acid plus ferric chloride solution.

Separation of carbonaceous minerals, the first step is to find out whether the carbonaceous material belongs to graphite, asphalt or coal. The floatability of these carbonaceous minerals is similar to that of molybdenite, but the density is smaller, and generally can be removed by re-election; the use of sodium hexametaphosphate and CMC to suppress the charcoal float molybdenum; or add ferric chloride, water glass and sodium hexametaphosphate to suppress the charcoal is also effective; the use of roasting to remove the organic charcoal is also one of the methods. It should be noted that all these methods of separation of carbonaceous minerals are currently unsatisfactory, or a problem that has not yet been fully resolved.

SiO2 (silicon dioxide) content in the vein is too high, often affect the molybdenum concentrate grade. It has been determined that: SiO2 content with molybdenum concentrate grade increases and decreases, the two have a tendency to consume each other. As long as the molybdenum mineral reaches the fineness of monomer dissociation, the SiO2 content can generally be reduced to below the standard. Add activated carbon to adsorb the oil medicine on the surface of molybdenum, and then add CMC to inhibit silicate veinstone, SiO2 content can also be reduced to below standard.