Manganese ore is silvery in colour and very hard and brittle in nature. It is always available in combination with iron, laterite and other minerals. Manganese in Alloy form is an essential input in steel making and is one of the most important metals in an industrial economy. Manganese of major commercial importance are: Pyrolusite (MnO – Mn about 63.2%) (ii) psilomelane (manganese oxide) containing water and varying amounts of oxides of Ba, K and Na as impurities; Mn commonly 45-60%) (iii) manganite (mn2O3H2O,Mn about 62.4%) and (v) braunite(3Mn2O3MnSiO3 – Mn about 62% and SiO2 about 10%)
Indian manganese ore deposits occur mainly as metamorphosed bedded sedimentary deposits associated with Gondite Series (Archaeans) of Madhya Pradesh, (Balghat, Chhindwara & Jhabua districts), Maharashtra (Bhandara & Nagpur districts), Gujarat (Pasnchmahal district), Odisha (Sundargarh district) and with Kodurite Series (Archaeans) of Odisha (Ganjam and Koraput districts) and Andhra Pradesh (Srikakulam and Vishakapatnam districts)
The total resources of manganese ore in the country as on Aporil 2013 are placed at 475 million tons as per UNFC system. Out of these 95.87 million tons are categorised as reserves and the balance 379.31 million tons are in the remaining resources category. Grade-wise Ferro Manganese grade amounts for 8%, medium grade 11%, BF grade 34% and the remaining 47% are of mixed , low, others, unclassified and not known grades including 0.35 million tons of battery/chemical grade.
State-wise Odisha tops the total resource with 40% share followed by Karnataka 20%, Madhya Pradesh 11%, Maharashtra 8%, Andhra Pradesh 4%, and Jharkhand & Goa3% each. Rajasthan, Gujarat and West Bengal together shared the remaining about 2% resources.
Classification of manganese ore, ferruginous manganese ore, siliceous manganese ore, dioxide manganese ore and manganiferous iron ore is laid down by BIS vide specifications no. IS:11895-2006 (Reaffirmed 2008) Manganese ore is an important material in iron and steel metallurgy, where it is used both in the ore form as such and as ferro manganese. Manganese improves strength, toughness, hardness and workability of steel, acts as a deoxidiser and desulphuriser and also helps in getting ingots free from blowholes. About 90 to 95% world production of manganese ore is used in metallurgy of iron and steel. Manganese has no satisfactory substitute in is major applications. The specifications of manganese ore by different industries are detailed below:
In iron & steel industry specification is laid down for manganese ore (BIS:11281-2005) However, specification based on the user industry indicate that normally manganese ore containing 28 to 35%Mn is used. Ore size generally varies from 10 to 40mm.
For manganese ore used in ferro manganese industry, besides manganese content other important considerations are high manganese to iron ratio and a very low content of deleterious phosphorus. Specifications of manganese ore for ferro manganese are prescribed by BIS (IS:4763-2006) BIS has also laid down specification of manganese ore sinters for blending for ferro manganese production (IS:12596-1989)
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The consumption of manganese ore in all industries was about 4.19 million tons in 2014-15 as against 4.18 million tons in 2013-14. Silico Manganese (63%) and ferro manganese 30% industries together accounted for about 93% consumption followed by iron & steel 6%. The remaining 1% was shared by battery, chemical, zinc smelter, alloy steel and glass industries.
The consumption of ferro manganese in 2014-15 decreased slightly to 123 thousand tons from 124.8 thousand tons in the previous year. Iron & steel industry was the bulk consumer of ferro manganese accounting for 94% consumption in 2014-15 the remaining 6% was consumed in alloy steel, foundry and electrode industries. Consumption of silico manganese which was 219.6 thousand tons in 013-14 increased marginally to 219.8 thousand tons in 2014-15.
Manganese alloy are the largest produced ferro-alloys in the wold with a share of about 41% of the global production of ferro alloys. Manganese is an essential requisite for iron & steel production due to its capability for sulphur fixing, de-oxidising and good alloying properties. For production of one ton of ferro manganese, about 2.6 tons of manganese ore , 0.5 ton of reductant and 3 MWh of electricity inputs are required. As per Indian Ferro Alloy Producers Association, the total installed capacity of manganese alloys including ferro manganese/silico manganese in the country was estimated to be around 2.75 million tons per annum.
The total production of various type of manganese alloys (high carbon ferro manganese, medium carbon ferro manganese and low carbon ferro manganese) was about 5.18 lakh tons in 2014-15 .
Silico Manganese is combination of 60-70% Mn, 10-20% silica and about 20% carbon. As per Monthly Statistics of Mineral Production, production of silico manganese was reported at 2.56 lakh tons in 2014-15.
The major factor driving the production of manganese alloys is high production growth of low nickel austenitic styai9nless steel. India is emerging as the largest producer of this steel where manganese is added substituting the expensive nickel.
Cost and technology militate substitution in major applications. However, for economic reasons there is only limited substitution in minor applications in chemical and battery industries. The steel industry has however made great strides in economising the use of manganese, largely through changes in steel-making techniques.
The deep-sea nodules can be a potential resource of manganese in the next decade to come. There is a trend towards using lower grade of ores in ferro-manganese production. New steel making practices and techniques are reducing the amount manganese consumed in the process. However, counter balancing this to some extent is a trend towards higher manganese specification for modern steels.
Imports of manganese ore and concentrates including ferruginous manganese ores and concentrates containing 20% or more manganese, agglomerated manganese ore sinters etc. are freely allowed. There is no change in policy for the period 2015-20.
The total world reserve of manganese ore is approximately 570 million tons of metal content which is unevenly distributed. Reserves are located in south Africa (26%), Ukraine 25%, Australia 17%. Brazil and India 9% each. Only a small fraction of global manganese reserve is clearly economic. This fact continues to support interest in deep-sea manganese nodules, which constitute an enormous untapped resource. Most nodule are found in areas of deep-sea floor at water depths of 5 to 7 km. The pacific Ocean alone is estimated to contain about 2.5 billion tons nodules containing about 25% Mn, making them similar in abundance to low-grade land based deposits. Most major steel making nations lack manganese resources. North America had less than 1% world reserves. Besides, United States have lean grade reserves and potentially high extraction cost. This situation has created an active global trade in manganese ore and manganese alloys.
World production of manganese ore in 2014 was estimated to be around 54.7 million tons as compared to 53.3 million tons 2013. China was leading producer contributing about 29% followed by South Africa 25%, Australia 14%, Gabon 7%, Kazaksthan 5%, India 4%. The production of manganese ore is linked with the production of steel. The steel industry consumes it in the form of ore and manganese alloys.
Production of crude steel is the single most important factor in the demand for manganese ore. Steel industry accounts for approximately 90% world demand for manganese. Carbon steel is the principal market accounting for 65 to 70% manganese consumption.
The production is estimated at 6.70 million tons and the apparent consumption is estimated at 7.31 million tons.
