Manganese finds a wide range of applications across human production and everyday life. It exists as ferromanganese, silicomanganese, and manganese metal. Globally, around 90% of the produced manganese is used in the iron and steel industry, with the remaining 10% allocated for non-ferrous metallurgy, chemicals, electronics, batteries, agriculture, and various other sectors.
Manganese in the steel industry
1. Manganese in the casting iron industry
The pig iron smelted in the blast furnace is generally an iron-carbon alloy, and the addition of a small amount of manganese not only improves the operation and processing of smelting but also improves the properties of pig iron.
1）Steelmaking pig iron (white iron)
White iron is the main material for steelmaking in flat furnaces and converters, accounting for more than 80% of the total pig iron production. With the improvement of technology, the converter gradually replaced the flat furnace. Manganese ore, as a slagging agent in the process of converter blowing, has a good and continuous slagging effect and does not produce metal spattering.
2）Foundry pig iron (gray iron)
Foundry pig iron may include rehashed pig iron, malleable iron and ductile iron. Foundry pig iron with manganese ore, there are no strict requirements for quality, manganese ore in the smelting ratio accounted for a small proportion of the impact on the quality of pig iron is small. The manganese content of 20%-25% of the ferromanganese ore can be.
2. Manganese in steelmaking
The main role of manganese in steelmaking is to deoxidize, desulfurize and act as an alloying element.
1）Used as a deoxidising agent
Steelmaking process, in order to improve the quality of steel, the need to remove carbon, sulfur and other harmful impurities in iron, the easiest process is to use the oxidation method, but a part of the iron and impurity elements are oxidised together, generating ferrous oxide, and ferrous oxide in the liquid steel solubility, so that the steel in the oxygen content of the steel, and the oxygen content of the steel will have an adverse effect on the performance of the steel, so the steel has a stringent requirement for oxygen content, generally not allowed to exceed 0.02% or even more stringent. Generally not allowed to exceed 0.02%, or even more stringent. Therefore, the steelmaking process must remove the excessive oxygen. Manganese is a good active metal, its chemical properties than iron active, manganese will be added to the liquid steel, can be reacted with ferrous oxide to form insoluble in steel oxide slag, floating in the liquid surface of the steel, so that the oxygen content of steel to reduce.
Although manganese in steel deoxidation ability than some other elements (such as calcium, aluminium, silicon) low, but because of its easy production, the price is relatively low, so it is still popular by the iron and steel enterprises, especially for refining boiling steel, the use of manganese ferroalloys deoxidation is ideal deoxidant, because of manganese deoxidation ability of the weaker, it can adjust the steel oxygen content, and not make the oxygen off to go over and over and can not be boiled. At the same time, the presence of manganese can also make silicon and aluminium deoxidation ability to enhance, because the deoxygenation product MnO and other oxides (such as Si02) can form a low melting point compounds and is conducive to the exclusion of the liquid steel.
2）Used as a desulphurising agent
Sulfur in the liquid steel in the form of iron sulfide exists, high sulfur in steel is prone to produce hot brittle, reducing the mechanical properties of steel, therefore, the steelmaking process must control the sulfur content. Manganese and sulfur binding force is greater than the binding force of iron and sulfur, when adding manganese alloy, the steel is easy to generate manganese and manganese melting point of manganese sulfide into the slag, thus reducing the sulfur content of steel, improve the malleability and rollability of steel.
3）Used as an alloying element
The reason why manganese can become an important alloying element of various steels is that it can strengthen the ferrite and refine the pearlite, improve the strength, hardenability, hardness and wear resistance of steel. For example, if 0.8-1.7 per cent of manganese is added to low alloy steel, the strength of the steel can be increased by 20-30 per cent compared with that of ordinary carbon steel.
3. Application of manganese in the non-ferrous metallurgical industry
Manganese has two main uses in non-ferrous metallurgical industry, one is in the wet smelting process of copper, zinc, cadmium, uranium and other non-ferrous metals, adding manganese dioxide or potassium permanganate as an oxidizing agent, so that the divalent iron dissolved in acid solution oxidized to trivalent, adjusting the pH value of the solution, so that the iron precipitation and removal. Another is with copper, aluminum, magnesium to generate many industrial value of the alloy, such as brass, bronze, copper, aluminum-manganese alloy, magnesium-manganese alloy, etc., manganese can improve the strength of these alloys, abrasion and corrosion resistance, such as magnesium in the addition of 1.3%-1.5% manganese alloy with better corrosion resistance and temperature resistance, is widely used in the aviation industry.
4. Manganese in the battery industry
Zinc-Manganese battery is still one of the most widely used batteries with the largest production value and output due to its ease of use and low price.MnO2 is the positive electrode of zinc-manganese batteries, which is reduced when the battery is discharged. Natural MnO2 (NMD), chemical MnO2 (CMD) and electrolytic MnO2 (EMD) are the main raw materials for preparing MnO2 for batteries. Natural Mn02 is generally used only in the production of paste-type zinc-manganese dry batteries due to its relatively low purity. Nowadays, as the amount of NMD suitable for the production of dry batteries in nature becomes less and less, and at the same time, with the technological progress and the improvement of people’s living standard as well as the growing awareness of environmental protection, the amount of NMD for the production of paste-type zinc-manganese batteries will gradually decrease, while the amount of EMD for the production of zinc-manganese dry batteries will continue to increase, and in particular the demand for the production of high-purity EMD for mercury-free zinc-manganese batteries will Especially the demand of high purity EMD for the production of mercury-free zinc-manganese battery will increase rapidly.
5.Manganese in the electronics industry
With the rapid development of electronic technology, the demand for manganese in the electronic industry is increasing. The basic materials of the electronic industry are magnetic materials, especially soft magnetic materials, and soft magnetic materials are dominated by manganese-zinc ferrite, which has a narrow remanent magnetic induction curve, can be magnetized repeatedly, and has the characteristics of high permeability, high resistivity and low loss under the action of high frequency, and at the same time, it is inexpensive and widely available, and it has replaced most of the nickel-zinc ferrite, and accounted for more than 80 per cent of the soft magnetic materials. For example, various inductor parts, transformers, coils and chokes made of Mn-Zn ferrite cores are widely used in communication equipment, home appliances, computer products and industrial automation equipment.
6.Manganese applications in agriculture
Manganese is an essential trace element for the growth of plants which aids in photosynthesis and nitrogen conversion. It also supports the functions of various enzymes and redox processes, as well as boosts the production of chlorophyll and the operation of carbohydrates. A severe deficiency of manganese in the soil results in crops that are withered and yellowed, leading to poor growth and reduced yield. Therefore, manganese is frequently included in fertilisers for agricultural purposes, particularly in manganese fertilisers that contain manganese sulphate. These fertilisers are commonly used as seed germination agents. In addition to its use as a fertiliser, manganese is also utilised as a fungicide and feed additive in agriculture.
7.Manganese in environmental applications
Manganese can also be applied to the treatment of sewage, waste gas and the purification of natural drinking water. Groundwater contains iron, when the concentration of iron is too high, it will have some effects on our production and life, such as the water will be muddy, and iron smell, easy to form scale, washed clothes will have rust-colored spots, printing and dyeing color is not bright, etc., so it needs to be purified, and manganese dioxide can oxidize the iron in the water, so that the water can be oxidized to insoluble soluble divalent iron into the trivalent iron hydroxide and remove it. In addition, manganese dioxide can also be used to purify arsenic in wastewater, purify hydrogen sulfide, sulfur dioxide and mercury in exhaust gas.
8.Manganese in medicine
Manganese serves as a disinfectant, pharmaceutical oxidant, and catalyst in the medical sector. Potassium permanganate is an extensively used disinfectant in medicine due to its remarkable oxidizing properties. A potassium permanganate solution with a concentration of 0.1% or above can disinfect and eliminate bacteria effectively. In addition to serving as an intermediary oxidising agent in the manufacture of the sedative fenugreek, manganese dioxide also acts as a catalyst in the production of the antipyretic and analgesic finasteride.
9.Manganese in other applications
Manganese dioxide is a commonly used catalyst in laboratories. For instance, it’s added to hydrogen peroxide to break down oxygen. In addition, manganese serves as a discolouring, colouring and clarifying agent in glass production. Potassium permanganate, or manganese dioxide, is frequently used as a catalyst in the soap industry. Furthermore, manganese soap is now utilised as a catalyst to make soap. Manganese dioxide serves multiple purposes. Besides being an oxidising agent in the printing and dyeing sector for producing bright green pigments, it also acts as an oxidising agent in the manufacturing of cinematographic films and photographic negatives. Additionally, manganese functions in the welding industry by promoting desulphurisation, deoxidation and enhancing weld strength.
Uses of Manganese Metal
Manganese metal is widely used as deoxidizing agent, desulfurizing agent, and alloying agent in the steel industry. There are four forms of manganese metal, manganese metal flakes, manganese metal lumps, Metallic manganese balls, and manganese metal powder.