MANGANESE :

Manganese is a chemical element with the symbol Mn. It is a silvery white metal with a hard brittle structure that belongs to the group 7. Manganese are the fifth most abundant metal found in the crust of the earth that are distributed widely in many countries.It is not found as a free element in nature but present in the combination with iron. It comprises about 1000ppm of the earth's crust.

Even though the manganese is not used in its pure form the demand of the manganese increases as the industrial usage increases. Thus mining manganese is prominent for industrial and economical development. Manganese ore is commonly distributed and mined in countries such as South Africa, China, Gabon, Brazil, India, Kazakhstan, Ghana, Ukraine and Malaysia. The top five manganese ore mining countries all over the world are

1. South Africa(Kalahari mine):

South Africa comprises about 80% of the manganese resources all over the world. It is the first largest manganese producer with annual production amounts up to 6.2 million tonnes. Australian firm South 32 and Jupiter mines in South Africa plays a significant role in mining manganese for the more than 3 million tons of manganese annually.

2. Australia(TEMCO and GEMCO)):

It is the second largest producer that contains about 15% of the world's manganese reserves and produces 3 million tonnes of manganese per year. It undergoes open pit mining and is claimed to be the largest and low-cost manganese ore producer in the world.

3. China( Wafangzi mine) :

The annual production of 2.9 million tonnes of manganese makes it a third largest producer all over the world. Guizhou province, that was discovered in 2017 is estimated to have the 203 million tonnes of manganese ore resources in China.

4. Gabon(Comilog):

The fourth largest producing company with average annual production of 1.8 million tonnes.

5. Brazil(Vale's Azul mine and Urucum mine):

It produces about 1 million tonnes annually and is the fifth largest producer all over the world. It offers three kinds of manganese products that are metallurgical ore, chemical ore and natural manganese dioxide.

 

MANGANESE MINING:

As manganese is one of essential components, more than 25 million tons of manganese are produced every year. Manganese are generally mined in open pits, but it has evolved from a primitive method to advanced technology process to increase the production of the manganese. Even though some of the manganese are deposited on the ocean, they cannot complete with land base production. When the ore is mined, it is sent for electrolytic processing or smelting

Freeing manganese from the open pit rock bed requires a lot of manpower and time. As you know in this method, the open pit mining using the standardised equipment and methods for overburden are removed to extract the manganese ore. The compact mining machineries and the advanced technologies are used in recent times to reduce the manual power and improve the production value of the manganese. In open pit mining the manganese are first identified in the process of

Countries like Ukraine and South Africa produce large amounts of the manganese core through underground mines. Most underground mining of the manganese is generally done by room and pillar method. Mining at Nchwaning and Gloria mines uses two shafts when it was initiated in 1981, one vertical hoisting shaft that is 450m deep and another vertical shaft. Now further rooms and pillar rooms are made with low grade ore for easier mining. In this mines

In case of mining in the sea, several processes were developed to remove the manganese constituent from the sea. This mining is not in practice due to the economical factors. They cannot also compete economically with the exploitation of the high grade terrestrial deposits.

USES OF MANGANESE :

Manganese is an important mineral that is found in many natural substances and products. It is used for a variety of different purposes, including in the manufacturing of steel, as a dietary supplement, and as an additive in many industrial processes.

1. Steel Production: Manganese is used in the production of steel and other alloys. It is an essential component of steel, as it helps to strengthen it and increase its resistance to corrosion. Manganese also promotes the formation of an oxide layer on the surface of steel, which further increases its durability.

2. Dietary Supplement: Manganese is an important mineral that is found in many foods and is also available as a dietary supplement. It plays an important role in the metabolism of carbohydrates and fats, as well as in the formation of connective tissue and bones. It is also thought to help lower cholesterol levels and improve brain function.

3. Industrial Processes: Manganese is often used as an additive in industrial processes. It is used in the production of dry-cell batteries and fertilizers, as well as in the manufacture of glass and ceramics. It is also used in the production of plastics, paints, and inks.

REFINING AND EXTRACTION :

The obtained ore containing iron oxides are first reduced in the blast furnace or electric furnace along with carbon to yield the ferromanganese and silico furnace.This is the main product to give rigidity and to reduce corrosiveness of the steel. The reduction of manganese oxide by carbon is a complex thermodynamic process, where the higher oxides of the Managanese like MnO2, Mn2O3 can be reduced to metal only at the elevated temperature.

The process of separation of manganese from the iron has a wide range of applications. The elements which have lower decomposition temperature or equal decomposition temperature than manganese will decompose or form soluble sulphates will be leached out with a manganese sulphate.

A more progressive extraction of manganese involves directly reducing manganese ore into a heap leach. In this a natural gas is allowed to go through the bottom of the heap. The gas provides the heat and the reducing agent carbon monoxide. The leachable form is then sent through the grinding circuit and to reduce the particle size of the manganese. The particle size of the ore may vary upto 150 micrometer to 25 micrometer. After increasing the surface area for leaching, the ore is then added to a leach tank of sulphuric acid and ferrous iron in the ratio of 1:6:1. This process recovers almost 92% of the manganese. In water leach, the mixture when subjected to water, the manganese is dissolved and the iron is undissolved and remains in the oxide form in solid state.

Smelting is done by the action of the gangue oxides. The acidic compound, silica can combine with MnO and prevent it from being reduced by using constituents like lime, magnesia or by the roasted limestone. As the end product, this results in more slag to dissolve manganese and lower the amount of metal recovered in the melt. The acidity or basicity of the slag can be reduced to silicon and enter the molten metal.

TOP MANGANESE PRODUCING COUNTRIES :

1. China: China is the world's largest producer of manganese, accounting for over 55% of the global production in 2019. China is also the world's largest consumer of manganese, and it has plenty of domestic reserves.

2. South Africa: South Africa is the second-largest producer of manganese in the world, producing over 4.3 million tonnes in 2019. It has the largest reserves of manganese in the world, estimated at over 170 million tonnes.

3. Australia: Australia is the third-largest producer of manganese in the world, producing over 3.2 million tonnes in 2019. It has the second-largest reserves of manganese in the world, estimated at over 110 million tonnes.

4. Gabon: Gabon is the fourth-largest producer of manganese in the world, producing over 1.5 million tonnes in 2019. It also has the third-largest reserves of manganese in the world, estimated at over 60 million tonnes.

5. Brazil: Brazil is the fifth-largest producer of manganese in the world, producing over 1.2 million tonnes in 2019. It has the fourth-largest reserves of manganese in the world, estimated at over 35 million tonnes.

ANNUAL MANGANESE USAGE :

The annual usage of manganese varies from country to country, and depends on the economic needs of each nation. In the United States, for example, manganese is used to produce steel and iron alloys, and is also used in the production of aluminum and copper alloys. In Europe, manganese is used in the production of steel, iron, and aluminum alloys, and is also used in the production of specialty alloys. Other nations may use manganese for a variety of industrial purposes, including in the production of chemicals, batteries, and fertilizer.

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