The 7 Most Useful Manganese Ore Beneficiation Methods
Price trend of manganese ore per ton from 2016 to 2022
in U.S. dolars per metric ton unit CIF
The data recorded by Statistics in 2020 shows that although in 2019 manganese ore price fell to the bottom, the price in 2020 still gets increased to 4.5 U.S. dollars per metric ton unit CIF even under the impact of COVID-19. Manganese ore prices are forecast to remain at global prices by 2020 over the next two years, which is good news to manganese ore suppliers.
Besides, Justin Brown, managing director of Element 25，said “Manganese has the traditional end uses in steel, and that market is fairly stable". As people's demand for laptops and electric cars increases, the output of lithium batteries has also soared, and the most important element in lithium batteries is manganese.
A wide range of uses of manganese ore
Manganese ore after the beneficiation process is applied in many respects in our daily lives. Of annual manganese ore production, 90 percent is used in steelmaking, and the other 10 percent is used respectively in non-ferrous metallurgy, chemical industry, electronics, battery, agriculture, etc.
- In the industrial field, the manganese ore is carbonized by blast furnaces or electric furnaces to produce ferromanganese which is mainly used to make steel or alloys.
- Lithium manganese battery has a high energy density, is a long-term reliable, safe, and small power source that can work normally under a wide range of conditions and is widely used in laptop and electric vehicles.
- In agriculture, manganese sulfate (MnSO4) can be added to the soil to promote plant growth, especially the growth of citrus crops.
- In addition, it is a good reducing agent, especially suitable for making paint and varnish dryers.
- Potassium permanganate (KMnO 4) is often used as a disinfectant, water purifier and antiseptic.
Different-grade Manganese ore applications
Industrial processing requirements for manganese ore
In the metallurgical industry, manganese ore is mostly used for manganese-forming ferroalloys and manganese metal. The former is used as deoxidizers or alloying element additives for steelmaking, and the latter is used to smelt certain special alloy steels and non-ferrous metal alloys. Manganese ore can also be used directly as an ingredient in steelmaking and ironmaking.
When smelting manganese-based iron alloys, the useful elements in manganese ore are manganese and iron. The level of manganese is the main indicator for measuring the quality of manganese ore. The iron content is required to have a certain ratio with the amount of manganese.
Phosphorus is the most harmful element in manganese ore. The phosphorus in steel reduces the impact of toughness. Although sulfur is also a harmful element, it has a better desulfurization effect during smelting, and sulfur is volatilized into sulfur dioxide or enters the slag in the form of calcium sulfide or manganese sulfide.
The metallurgical industry's requirements on manganese grade
In the pig iron making process, iron content is not limited, and the total content of manganese and iron is preferably 40% to 50%.
|Applications in Metallurgy||Manganese content (%)||Ferromanganese (%)||Phosphorus manganese (%)|
|Low carbon ferromanganese||36%～40%||6～8.5||0.002～0.0036|
|Carbon Ferro Manganese||33%～40%||3.8～7.8||0.002～0.005|
|Manganese Silicon Alloy||29%～35%||3.3～7.5||0.0016～0.0048|
|Blast Furnace Ferromanganese||30%||2～7||0.005|
Grade requirements of manganese ore in chemical and light industries
In the chemical industry, manganese ore is mainly used to prepare manganese dioxide, manganese sulfate, and potassium permanganate. It is also used to make manganese carbonate, manganese nitrate and manganese chloride.
- Manganese dioxide powder requires MnO2 content over 50%.
- Making manganese sulfate, Fe≤3%, Al2O3≤3%, CaO≤0.5%, MgO≤0.1%.
- When making potassium permanganate, Fe≤5%, SiO2≤5%, Al2O3≤4%.
Natural manganese dioxide is a raw material for manufacturing dry batteries. The higher the content of MnO2, the better product is.
- The content standards of harmful elements such as Ni, Cu, CO, Pb are: Cu<0.01%, Ni<0.03%, Co<0.02%, Pb<0.02%.
- The particle size of the mineral powder should be less than 0.12mm.
7 methods for dressing high-grade manganese ore
Since most manganese ore is a fine-grained or fine-grained inlay, and there are a considerable number of high-phosphorus ore, high-iron ore, and symbiotic beneficial metals, it is very difficult to beneficiate.
At present, commonly used manganese ore beneficiation methods include physical beneficiation (washing and screening, gravity separation, strong magnetic separation, flotation separation, joint beneficiation), chemical beneficiation (leaching method) and fire enrichment, etc.
1. Washing and screening
Manganese ore dressing plant in South Africa
Washing is the use of hydraulic washing or additional mechanical scrubbing to separate the ore from the mud. Commonly used equipment includes washing sieves, cylinder washing machines and trough ore-washing machine.
The washing operation is often accompanied by screening, such as direct flushing on the vibrating screen or sifting the ore (clean ore) obtained by the washing machine to the vibrating screen. Screening is used as an independent operation to separate products of different sizes and grades for various purposes.
2. Gravity separation
At present, the gravity separation is only used to beneficiate manganese ore with simple structure and coarse grain size and is especially suitable for manganese oxide ore with high density. Common methods include heavy media separation, jigging and tabling dressing.
At present, the process of manganese oxide ore dressing in China is generally to crush the ore to 6~0 mm or 10~0 mm, and then the coarse-grade for jigging, and fine-level for tabling dressing.
It is essential to recover as much manganese as possible in the gravity concentration zone because its grinding cost is much lower than the manganese in the flotation process, and simple operations are more active.
3. Strong magnetic separation
Manganese ore is a weak magnetic mineral [Specific magnetization coefficient X=10×10^-6~600×10^-6cm3/g].
Under the magnetic separator with magnetic field intensity Ho=800～1600 kA/m (10000～20000oe), it can be recycled to increase the manganese grade by 4% to 10%.
Because of the simple operation, easy control and strong adaptability of magnetic separation can be used for dressing various manganese ore, and it has dominated the manganese ore dressing in recent years.
4. Gravity-magnetic separation
Gravity-magnetic separation plant of manganese ore mainly deals with leaching manganese oxide ore, using the jig to treat 30~3 mm of cleaned ore can obtain high-quality manganese-containing more than 40% of manganese. And then can be used as manganese powder of battery raw material.
The jigging tailings and less than 3 mm washed ore are ground to less than 1mm, and then being processed by strong magnetic separator. The manganese concentrate grade would be increased by 24% to 25%, and reaches to 36% to 40%.
5. Strong magnetic - flotation separation
Due to the floatability of manganese, foam flotation is also applicable to manganese concentrates.
The strong magnetic-flotation separation has better adaptability, and it not only effectively removes the slime but also improves the quality of flotation.
Adopting strong magnetic-flotation desulfurization can directly obtain the integrated manganese concentrate product; the use of petroleum sodium sulfonate instead of oxidized paraffin soap as a collector can make the pulp be sorted at neutral and normal temperature, thus saving reagent consumption and energy consumption.
After froth flotation, the recovery of manganese ore can reach 85.41%.
Note: If the manganese ore has a high calcite content, the calcite must be removed by flotation first, otherwise low-grade manganese concentrate will be produced.
Froth flotation manganese ore processing plant in India
6. Fire enrichment
The enrichment of manganese ore by fire is another dressing method for high-phosphorus and high-iron manganese ore which is difficult to select. It is generally called the manganese-rich slag method.
It is a high temperature beneficiation method for selectively separating manganese, phosphorus, and iron by controlling the temperature of them in a blast furnace or an electric furnace.
The fire enrichment process is simple and stable, and the iron and phosphorus in the ore can be effectively separated to obtain manganese-rich slag with low-iron and low-phosphorus.
The manganese-rich slag generally contains 35% to 45% Mn, Mn/Fe 12-38, P/Mn<0.002, and is a high-quality raw material to manganese-based alloy. Therefore, fire enrichment is also a promising method for mineral processing for low-manganese with high-phosphorus and high-iron.
Manganese ore after froth flotation process may need nodulizing or sintering which can substantially improve the grade of manganese ore.
7. Chemical manganese separation
Manganese ore also can be recovered by acid leaching for production of battery grade manganese dioxide for low-manganese ores. Leaching of manganese ore was carried out with diluted sulphuric acid in the presence of pyrite in the temperature range from 323 to 363 K.
Equipment for the Manganese Ore Processing Plant
The main crushing equipmentThe crushing process is necessary because all rocks and ore must be crushed into small size before proceeding to the next step. The main crushing equipment includes primary crusher-jaw crusher; secondary crushing equipment- hydraulic cone crushers.
Jaw crusher firstly crushes manganese ore into minus 2″ product.
After vibratory screen removing minus 3/8″ product, the minus 2″ plus 3/8″ product is fed to hydraulic cone crusher to smaller-sized ores.
After processed by hydraulic cone crusher, the smaller-sized manganese ore would be fed to grinding machine- ball mill. It can grind the ore to a relatively fine and uniform particle size, which lays a foundation for further magnetic separation of manganese ore.
The spiral classifier
It is indispensable grading equipment in the manganese ore beneficiation plant. Because by taking advantage of the natural settling characteristics of ore, a spiral classifier can effectively classify and separate the manganese ore size to help control the amount of grinding required.
Froth flotation separator or magnetic separator
The flexibility of flotation is relatively high. You can choose different reagents according to the type and grade of the ore. Although the entire process of froth flotation is expensive, it can extract higher-grade manganese ore.
The magnetic separator is a highly targeted magnetic separation device specially developed for the properties of manganese ore. The device not only has the advantages of small size, lightweight, high automation, simple and reasonable structure, but also has high magnetic separation efficiency and high output.
Since the minerals separated by the magnetic separator contain a certain amount of moisture, they need to be dried by a dryer.
The best choice is rotary dryer which has the advantages of easy handling, stable operation, high output, low carbon and environmental protection, etc.
Manganese beneficiation plant manufacturer
If you want to beneficiate high-grade manganese ore and maximize the value of manganese concentration, Fote Company is an ore beneficiation equipment manufacturer with more that 35-years designing and manufacturing experience and can give you the most professional advice and offer you all machines needed in the ore beneficiation plant (form crushing stage to ore dressing stage). All machines are tailored to your project requirements.