Since most manganese ore is fine-grained or fine-grained intercalation, and there are a considerable amount of high-phosphorus ore, high-iron ore and associated (associated) beneficial metals, it brings great difficulty to the selection. At present, the commonly used manganese ore beneficiation methods include physical beneficiation (washing and screening method, gravity beneficiation method, strong magnetic beneficiation method, flotation method, combined beneficiation method), chemical beneficiation (leaching method) and special beneficiation method (fire method enrichment method)
1.Washing and Screening Method
Ore washing mainly uses hydraulic washing or additional mechanical scrubbing to separate the ore from the mud. Common equipment includes ore washing screens, drum washing machines and trough washing machines. Usually, the ore washing operation is accompanied by the sieving operation, such as flushing water directly on the vibrating screen for cleaning or sending the ore (net ore) obtained by the washing machine to the vibrating screen for screening. Screening can be used as an independent operation to separate products of different particle sizes and grades for different purposes.
2.Gravity Separation Method
At present, the gravity separation method is only applicable to the separation of manganese ore with a simple structure and a coarse grain size, especially the manganese oxide ore with a higher density. Commonly used methods include heavy media beneficiation, jig beneficiation and shaker beneficiation.
The process of processing manganese oxide ore is generally crushing the ore to 6-0mm or 10-0mm, and then classifying, coarse grade particles are sent to jig sorting, and fine grade particles are sent to shaker for sorting.
3. Strong Magnetic Separation Method
Manganese mineral is a weak magnetic mineral (specific magnetic susceptibility coefficient X = 10 × 10-6 ~ 600 × 10-6cm3 / g). It can be used in high magnetic field magnetic separator with magnetic field intensity Ho = 800-1600kA / m (10000-20000oe). It is effectively recovered, and the manganese grade can be generally improved by 4% -10%.
Because of its simple operation, easy control, and strong adaptability, the magnetic separation method is widely used for the separation of various manganese ore. In recent years, it has occupied an important position in the manganese ore beneficiation. Magnetic machines have also been successfully developed.
4.Gravity Separation-Magnetic Separation Method
The weak magnetic separation is performed to obtain the ferromagnetic manganese concentrate and the weak magnetic separation tailings. The tailings are fed into a magnetic separator for strong magnetic separation, and the strong magnetic separation tailings and concentrates are obtained. To obtain heavy beneficiated manganese concentrates and tailings.
5.Strong Magnetic Separation-Flotation
The strong magnetic separation-flotation method has good adaptability. The strong magnetic separator not only effectively removes slime, but also improves the grade of flotation. Comprehensive manganese concentrate products can be obtained directly by using strong magnetic-flotation desulfurization; using sodium petroleum sulfonate instead of oxidized paraffin soap as a collector can enable the pulp to be separated at neutral and normal temperature, saving drug consumption and energy consumption.
Generally, manganese leaching methods include direct leaching, roasting leaching and biological leaching. Among them, the direct leaching method includes a continuous disulfate method, a sulfur dioxide method, a ferrous sulfate method, and the like.
Taking the sulphur dioxide manganese leaching method as an example, the manganese ore is slurried, and the sulphur dioxide gas is passed through. The manganese oxide in the ore is converted into MnSO4 and MnS2O6. When lime milk is added to the filtrate, manganese hydroxide precipitates, and solid manganese hydroxide is obtained after filtration. This method is suitable for processing low-grade, embedded fine-grained manganese oxide ore.
The above are common manganese ore beneficiation methods. In actual production, most of the manganese carbonate ore beneficiation methods use strong magnetic beneficiation, heavy media beneficiation, and flotation. The manganese oxide ore is mainly based on the gravity separation method, and most of them adopt the washing-re-selection process or the washing-reduction roasting magnetic separation-re-selection process. Of course, it is often necessary to combine two or more ore dressing methods for difficult-to-dress manganese ores.