Niobium Mining

NIOBIUM :

The most important mineral from which niobium metal is gained is documented as pyrochlore. The world's major dump is situated in Araxa, Brazil and is possessed by Companhia Brasileira de Metalurgia e Mineracao (CBMM). The reserves are enough to supply present world command for about 500 years, and about 460 million tons. The mining of battered ore, operation between 2.5 and 3.0% Nb2O5, is performed by easy open pit mining devoid of the requisite for drilling and explosives. Roughly 85 to 90% of the niobium industry expands its niobium ores from resources other than those connected with the mining of tantalum containing ores.

An additional pyrochlore mine in Brazil is possessed and functioned by Anglo American Brazil Mineracao Catalao and encloses 18 million tons at 1.34% niobium oxide. The 3rd foremost dump of pyrochlore being vigorously mined is the Niobec Mine in Quebec, Canada, possessed by Cambior, with stores of 18,000 tons. In all 3 facilities, the pyrochlore mineral is coursed by first and foremost physical processing expertise to give a contemplate ranging from 55 to about 60% niobium oxide.

These 3 companies construct about 85% of the world's command for niobium merchandises, with most of that productivity being in the outward appearance of ferro-niobium with an ostensible 60% niobium oxide pleased, for building high-strength, low-alloy steel. Columbite, a mineral with a relative amount of Nb2O5:Ta2O5 spacing from 10:1 to 13:1 happens in Brazil, Nigeria, and Australia, also supplementary countries in central Africa. Niobium is convalesced when the ores are coursed for tantalum. Niobium is also established, in very diminutive quantities, in the slag shaped from the smelting of some tin ores.

MINING AND PROCESSING :

The niobium ore is generally mined by the open pit method, where it is divided into blocks and processed by ripping, bulldozing, loading, and transporting. This open-pit mining method is followed in Brazilian areas whereas in other niobium ore containing parts, the underground methods are followed. The concentration of ore is attained by crushing and grinding followed by magnetic separation for separating magnetite, after which desliming and flotation separation is carried.


 

NIOBIUM ORES :

Niobium mostly occurs as an oxide and in combination with tantalum. Pyrochlore[(Na, Ca)2Nb2O6F] and columbite [(Fe,Mn)(Nb, Ta)2O6] are the major mineral ores of niobium, which constitute niobate, tantalate, iron, and manganese in definite proportions. Pyrochlore usually occurs in carbonatites and in pegmatite derived from alkalic rocks combined with zirconium, titanium, thorium, uranium and rare-earth minerals. Columbite is normally found in intrusive pegmatite and biotite and in alkalic granites. These ores are mined as a by-product of other metals since they are found in small deposits and are irregularly distributed.

Large pyrochlore mines are found in the Brazilian states of Canada and large columbite deposits are found in Nigeria and Congo. In Nigeria, the concentrates of columbite are obtained as by-products of tin mining.

EXTRACTION AND REFINING :

Most commercial extraction and refining processes for the preparation of niobium consist of a series of progressive operations. After the mining process is carried, the pyrochlore ore concentrates are reduced to ferroniobium which is basically niobium pentoxide. The procedure starts with the ore concentrates to be mixed in a rotary mixer lined with magnesite refractory bricks with hematite and aluminum powder, following fluorspar and lime fluxes in small amounts after which it is unloaded into steel containers lined with magnesite refractory bricks. The charge is placed here in circular concave pits made from a mixture of lime, fluorspar and silica sand. The reduction is caused by the ignition of a mixture of aluminum powder and sodium chlorate or barium peroxide. This exothermic reaction lasts about 15 to 30 minutes and the temperature reaches to 2,400 ?. The gangue impurities from the concentrate which includes all the thorium and uranium oxides enter the molten slag. When the entire reaction is finished, the slag is tapped off and the vessel is lifted allowing the metal to solidify in the sand, forming an alloy of ferrroniobium.


This alloy is then crushed to particle sizes of 10 millimetres for marketing purposes. It is found that the content of this alloy is 62 to 69 percent niobium, 29 to 30 percent iron, 2 percent silicon and 1 to 3 percent aluminum. This ferroniobium is mixed with iron oxide and aluminium and is reduced to obtain niobium and iron through the aluminothermic process. The component metals can be purified in an electron beam furnace or the alloy can be used as it is. Aluminothermic reactions are exothermic chemical reactions where aluminium is used as the reducing agent at a high temperature. These reactions are used for the production of several ferroalloys. In the case of reduction from ferroniobium to niobium, the reaction takes place as follows:

3 Nb2O5 + 10 Al ? 5 Al2O3 + 6 Nb

Ferroniobium is an important alloy for the production of niobium. 80% of the niobium production in the world is obtained through ferroniobium only.

 

TOP NIOBIUM PRODUCING COUNTRIES :

production of niobium

USES OF NIOBIUM :

* It finds its use in the manufacturing of various steel types.

* Ferroniobium is alloyed with steel for marketing purposes.

* Niobium oxide can be used in camera lenses and for coating on glass for computer screens.

* Niobium powder is useful in making niobium capacitors for electronic circuits.

* Niobium sheets, wires, tubes, rods are useful in physics experiments.

* Niobium alloys are strong because of which they are used in pipelines construction.

* Other uses include in making of jet engines and rockets, beams and girders for buildings and oil rigs, and oil and gas pipelines.

 

ANNUAL NIOBIUM USAGE :

 

 

NOBIUM PRODUCTION IN THE WORLD :

Canada is known to be the second largest producer of this rare metal at 4,167 metric tons per annum contributing about 9% of the world's niobium production. North America is solely dependent on Canada for pyrochlore. The city with the largest deposit of niobium is Araxa located in the Minas Gerais state that is situated in Saint-Honore-de-Chicoutimi in Quebec, Canada. Brazil is found to be the highest producer of niobium. The measure of niobium produced by Brazil currently is 40,000 metric tons per year. Nigeria is known to have reserves of 14,000 tons of niobium and is the second highest African producer of niobium after Rwanda. Niobium mines are located in Nigeria in Jos Plateau, Kano and Bauchi states. The mining industry in Nigeria contributes 0.3% of its Gross Domestic Product (GDP).

Rank

?Country

Production of Niobium (Metric Tons)

1

 Brazil

40,000

2

 Canada

4,167

3

 Australia

200

4

 Rwanda

80

5

 Nigeria

35

6

 Mozambique

29

 

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