Processing flow of molybdenum ore from raw ore to concentrate

1. Crushing and grinding: particle size control lays the foundation for sorting

The raw ore is coarsely crushed by a jaw crusher or a cone crusher, and then enters a semi-autogenous ball mill and a screening equipment to form a closed-loop circulation to control the ore particle size within a reasonable range. In the grinding stage, a ball mill and a hydrocyclone are combined to make the ore fineness reach -0.074mm, accounting for more than 80%, to ensure that molybdenite and gangue are fully dissociated, creating conditions for subsequent flotation.

2. Mixed flotation: preliminary separation of polymetallic minerals

The grinding product enters the copper-molybdenum mixed flotation link. In the weakly alkaline slurry (pH=8~10), collectors and frothers are added to make molybdenite and copper sulfide ore float together to form a mixed concentrate. In this stage, the slurry concentration (30%~35%) and temperature (about 40℃) are adjusted to optimize the difference in mineral floatability and achieve the initial enrichment of molybdenum minerals.

3. Separation and selection: key to improving the quality of molybdenum concentrate

After the mixed concentrate is classified by the hydrocyclone, it is ground to a finer particle size (such as -0.038mm accounting for 80%), and inhibitors such as sodium hydrosulfide are used to suppress copper minerals, and copper and molybdenum are separated by flotation columns or sealed flotation machines. The separated molybdenum coarse concentrate is selected by multi-stage flotation columns, and combined with de-drugation, concentration, filter pressing and other processes, finally obtaining a molybdenum concentrate with a grade of ≥50%.

Key reagent system for molybdenum ore flotation process

1. Collector: Molybdenite selective adsorption core

Hydrocarbon oils: kerosene and diesel are traditional collectors, which use the natural hydrophobicity of molybdenite to achieve adsorption. The dosage is usually 150~200g/t, which is suitable for the recovery of coarse molybdenite.

Xanthates: Butyl xanthate, potassium amyl xanthate, etc., have stronger collection ability than oils, and are often mixed with kerosene to improve the recovery rate of fine molybdenite.

Thiocarbamate: When O-isopropyl-N-ethylthiocarbamate is compounded with mercaptobenzothiazole, the recovery rate of copper and molybdenum is increased by 5%~10% compared with a single agent.

New mixed collector: Vegetable oil (cottonseed oil, palm oil) and xanthate are compounded, or amines (mixture of azepine and propylene glycol) are used as auxiliary collectors, which can reduce the amount of lime by more than 30% and improve the flotation environment.

2. Frothing agent: foam stability regulation

Traditional frother: pine oil, MIBC (methyl isobutyl carbinol), dosage 20~200g/t, forming a stable foam layer to promote mineral floating.

New frother: HP-700 modified amine frother, suitable for molybdenum ores containing clay minerals, maintains good foaming performance in a wide pH range, and reduces fine mud inclusions.

3. Inhibitor: Selective inhibition of gangue minerals

Silicate inhibitor: Water glass, sodium hexametaphosphate, inhibit quartz, feldspar and other siliceous gangue, dosage 500~2000g/t.

Carbonate inhibitor: Sodium carbonate adjusts the pH of the slurry to weak alkalinity. When combined with zinc sulfate and potassium ferrocyanide, it can effectively inhibit talc and other layered silicate minerals, and achieve the separation of molybdenite and talc.