the 7 most useful manganese ore beneficiation methods | fote machinery
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 25said 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.
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 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.
Applications in Metallurgy
Manganese content (%)
Phosphorus manganese (%)
Low carbon ferromanganese
Carbon Ferro Manganese
Manganese Silicon Alloy
Blast Furnace Ferromanganese
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.
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.
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.
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.
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.
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.
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%.
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.
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.
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 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.
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.
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.
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.
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.
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iron ore mining and dressing - tec-science
Iron is one of the most important metals in mechanical engineering, as it is present in sufficient quantities on earth. The extraction of iron can therefore be very economical. However, pure iron is not suitable for use as a construction material. It is much too soft in its pure form and has too little strength to meet most mechanical requirements. For this reason, it is necessary to use alloying additives to give the iron its hardness and strength.
It has been shown that carbon is an excellent alloying element. Within certain limits, carbon has a very high strength and hardness increasing effect and is very cheap compared to other alloying elements. Such a compound of iron and carbon is generally referred to as steel, where the carbon content is less than 2 %. The special importance of steel in mechanical engineering is already demonstrated by the daily production of around 4 million tons of steel!
In contrast to the direct reduced iron process, the blast furnace process can be operated on a large scale. The blast furnace process accounts for over 80 % of total steel production. Therefore, the blast furnace process will be discussed in more detail in the following.
Before the iron ores can be fed to the ironworks, they must first be mined (ore extraction) and specially processed for the blast furnace process (ore processing). These process steps are described in more detail in the following sections.
Iron does not occur in nature as a pure substance but as a compound in rocks, which can contain up to 50 % iron. These ferrous rocks are also called iron ores. The iron compounds contained therein are mainly iron oxides, but also iron carbonates or iron sulphides. The most important iron oxides include:
In addition to the actual iron compounds, however, the iron ore always contains various (undesirable) admixtures, which are not of interest for steel production. These waste rocks are also referred to as gangueand are often oxides such as, for example:
These unwanted admixtures are also the reason why steel always contains accompanying elements such as silicon, manganese, phosphorus and sulphur as well as other elements. The maximum values to be observed for these accompanying elements are prescribed for steels depending on the steel grade.
For technical and economic reasons, it makes sense to reduce the gangueto a minimum even before the iron ore actually melts down. Otherwise, an unnecessarily high use of coal or thermal energy in the subsequent blast furnace process would be necessary if too much impurities had to be melted. This means that the mined iron ores need to be specially processed in advance before the blast furnace process.
Regions in which iron ore has formed over millions of years (e.g. through volcanism) and can be mined economically are also referred to as iron ore deposits. Especially many ore deposits can be found in countries such as China, Australia, Brazil, India and Russia. These countries account for around 85 % of the total global iron ore mining volume.
The iron ore extracted in the deposits, mostly by blasting, is initially very coarse and unwieldy, which gives this untreated rock the name coarse ore. After the coarse ore has been extracted, it is crushed directly at the deposits with the aid of cone crushers or jaw crushers to more manageable sizes of approx. 15 mm. This is also known as lump ore. In addition to lump ore, fine ore (approx. 1 mm) and ground ore (orepowder) (approx. <0.1 mm) can also be obtained by crushing and grinding.
Lump ore can usually fed directly into the blast furnace process, because the special processing of these ores is relatively complex and expensive, so that it is only to a certain extent economically worthwhile to process this ore. Fine ore and ore powder, on the other hand, are specially processed for the blast furnace process. This ore processing will be discussed in more detail in the next section.
After the iron ore has been prepared by crushing and grinding during ore extraction, the ore is actually processed. The aim of this is to reduce the undesirable high proportion of admixtures to a desired minimum in order to increase the iron content. This is done by processes such as flotation or magnetic separation. Subsequently, the milled ores are lumped by sintering or pelletizing in order to optimize chemical reactions in the blast furnace process.
In principle, the undesirable gangue can never be completely separated from the iron ores during ore dressing. This means that a certain amount of unwanted elements always enters the blast furnace process. Slag-forming aggregates (and other special processes) are then used to separate these unwanted substances during or after the blast furnace process.
In froth flotation, the different wettability between the iron compounds and the undesirable gangue is used. While, for example, water is wettening the gangue relatively well, i.e. adheres to them, water tends to roll off the ferrous particles. This effect can finally be used to separate gangue from iron compounds.
For this purpose, the ground ores (obtained by crushing and grinding) are mixed with water infroth flotation cells. This aqueous suspension is also called slurry. Gas bubbles are generated in the slurryby air supply or stirrers on the floor. Due to the rather low water wettability of the iron-containing ore powder, the rising gas bubbles adhere relatively well to them. The significantly better wettability of the gangue, however, means that they remain completely wetted with water and gas bubbles hardly adhere to them.
While the ferrous particles are thus floated upwards with the adhering gas bubbles, the gangue in the slurry sinks to the bottom. To prevent the gas bubbles from bursting after ascent and to prevent the iron ore from sinking back to the ground, foam stabilizers are added, which create a relatively stable foam layer on the surface. The fluffy, strongly ferrous foam can then be skimmed off and dried. The gangue remaining in the slurry is pumped off after froth flotation and disposed of.
In magnetite-containing rock, there is another possibility of separating gangue and iron ore. As the name magnetite already suggests, this type of iron ore is a magnetic rock. This allows the ground ore to pass relatively easily through magnetic separators, where the ferrous rock is separated from the rest of the gangue (magnetic separation).
For this purpose, the ground ore is mixed with water to a mud-like mass and passed over a rotating magnetic roller. The ferrous mud adheres to the rolls and is then stripped off and dried. The separated gangue falls through a separate funnel into a container and is disposed of. In principle, this process is also suitable for the iron ores siderite and hematite, which become weakly magnetic when heated.
After processing the iron ore in froth flotation cells or magnetic separators, the finely ground ores cannot be fed directly to the blast furnace, as the enormous compression due to the charging in the blast furnace would impede gas flow. The ores must therefore be made lumpy so that there are sufficient cavities in the charging column for a good gas flow through. The lumpy pieces are made by sintering and pelletizing.
During sintering, the fine ores are first mixed with additives and fine coke. This mixture then passes through a funnel onto a circulating moving grate. Ignition flames then set the mixed coke on fire. Due to the high temperatures, the ores bake together to a sinter cake (called sintering). Air vents provide a suction effect (chimney effect) so that the sinter cake actually bakes together over the entire cross-section. Afterwards, the porous sinter cake is broken to grain sizes of approx. 15 mm by rotating blades. Such sinter plants are usually located directly in the ironworks.
During pelletizing, ore powder is rolled into iron ore green pellets in rotating drums together with water, binding agents and additives.Globules with grain sizes of approx. 15 mm are produced, which are then baked into porous pellets. Pellets are mainly produced by special ore suppliers and then delivered to the ironworks.
The main advantages of sintering or pelleting are the increased controllability of the composition and the accelerated chemical reaction in the blast furnace process due to the porosity (better gas flow).
The extraction of raw minerals begins with the mining of rich ores, which are then cut up in crushers and grinders. The pieces of rock initially weighing tonnes are ground down to a few tenths of a millimetre. This grinding process, which often covers six decimal orders of magnitude of the particle size, is carried out in several steps. Classic crushers are used for the coarse grinding process. The primary and secondary grinding takes place in autogenous (AG) or semi-autogenous (SAG) mills and in ball or rod mills. If the raw material is sufficiently finely distributed, it is classified in wet-chemical flotation cells according to reusable material and waste rock (residual mineral). The material substrate obtained is called concentrate.
The particle size is of particular importance in this process. If the particles are too large, unwanted accessory minerals cannot be separated from the ore. The ore concentrate obtained only has a low purity. Overgrinding, on the other hand, results in high milling costs and low throughput as well as an increased need for chemicals in flotation. Furthermore, flotation cells are sensitive to solid overloading. Another relevant process parameter is therefore the solid concentration of the ore suspensions fed to the flotation cells.
Compliance with the ideal grain size and the solids load in the transition from the last grinding stage for the flotation cell requires monitoring of the ore suspension in real time. This measurement task places high demands on the technology used. It is therefore important, on the one hand, to record relevant and representative sample quantities from the huge streams of the main product. On the other hand, the abrasive mineral slurries flowing at a high speed require robust and wear-resistant sensors.
The OPUS measuring system based on ultrasonic extinction fulfils these requirements and provides simultaneous real-time analysis of both the particle size distribution and the solid concentration. The acoustic measurement method allows the ultrasonic measuring probe to be immersed directly into the volume flow and, in this way, analyses up to 300 litres of undiluted and unconditioned mineral slurry within minutes.
In practice, a combination of primary samplers and a MULTIPLEXER is frequently applied in order to monitor several grinding lines using only one OPUS sensor. Initially, partial streams are diverted from up to four main product streams and led to the MULTIPLEXER. This fully automatically ensures sample feeding to the OPUS-sensor, which is seamlessly integrated in the MULTIPLEXER Use of the MULTIPLEXER also provides a reduced product flow in the OPUS sensor measurement zone, which in turn significantly increases the already very good service lives.
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