Niobium | Mineral Monday

Niobium | Mineral Monday

There was national excitement when Kenyans heard that Cortec Kenya Mining had discovered niobium worth Sh. 51 Trillion in Kwale’s Mrima Hills. Isn’t that exciting? But what really do we know about niobium? Other than it is in Kenya?

Niobium is a shiny steel-gray , soft and ductile transitional metal that takes on a bluish tinge when exposed to air at room temperature for a long time.  The metal starts to oxidize in air at high temperatures, and when handled hot must be done so under a protective atmosphere so as to minimize oxide production.

Fact Sheet

History

Niobiums’s history is kind of confusing. But not to worry, The RocKe Scientist has got you covered.

In around 1734, John Winthrop the Younger (the first governor of Connecticut) discovered a mineral that he decided to call columbite [(Fe, Mn, Mg)(Nb, Ta)2O6]. He sent a sample of this to England’s British Museum where it sat in the mineral collection shelves for years.

1801 is when Charles Hatchett analyzed it. I It may seem like 67 years is a long time but not to us geologists). His analysis showed an unknown element which he was not able to isolate and so decided to call it columbium.

In 1809, William Hyde ( English chemist and physicist) compared columbite [(Fe, Mn)(Ta, Nb)2O6]  and tantalite [(Fe, Mn, Mg)(Nb, Ta)2O6] and concluded that colombium was actually just tantalite. The confusion arose because niobium (colombium) and tantalum are similar metals that are usually found together  and are fifficult to separate.

In 1844, Heinrich Rose rediscovered this element and renamed ti to niobium, when he produced two new acids, niobic acid and pelopic acid, from samples of columbite and tantalite. These acids are very similar to each other and it took another twenty-two years and a Swiss chemist named Jean Charles Galissard de Marignac to prove that these were two distinct chemicals produced from two different elements. Metallic niobium was finally isolated by the Swedish chemist Christian Wilhelm Blomstrand in 1864. He reduced the chloride by heating it in a hydrogen atmosphere. Today, niobium is primarily obtained from the minerals columbite and pyrochlore [(Ca, Na)2Nb2O6(O, OH, F)]

Fun Facts

The name niobium is from the Greek word “Niobe” meaning “daughter of Tantalus” (tantalum is closely related to niobium in the periodic table).

Scientists believe that niobium’s abundance in the Earth’s crust is about 20 parts per million(33rd most common element in the Earth’s crust). That makes it about as abundant as nitrogen and lithium, and slightly more abundant than lead. Some think that the abundance on Earth should be much greater, but that the “missing” niobium may be located in the Earth’s core due to the metal’s high density.

Niobium is used in jewelry both because it is compatible with skin, and because it can be colored by electrolysis (the thickness of the oxide layer determining the color by interference).

These are oxide-layer-colored earrings by Holly Yashi, who seems to be a major producer of niobium jewelry.
These are oxide-layer-colored earrings by Holly Yashi, who seems to be a major producer of niobium jewelry.

 

Kenya’s deposits found in Kwale are ranked amongst the top six in the world.

Niobium has the largest magnetic penetration depth of any element

There are 18 known isotopes of niobium.

This element, in the form of coltan (columbite-tantalite) has enhanced civil war and pollution in the DRC

In Short

Properties

Symbol

Nb

Atomic No.

41

Atomic Mass

92.90638

Electrical Config.

Kr d4d

Melting Point

2469°C

Boiling Point

4744°C

Density

8570 kg/m3

Hardness

6

Luster

Metallic

Price: $42 a kg in 2013

Occurrence

In Kenya, niobium is found in Kwale’s Mrima Hills (The Coast)

Niobium Minerals

  • Columbite
  • Pylochlore
  • Lueshite
  • Natroniobite
  • Franconite
  • Ternovite
  • more

World Production [2012]

Rank Country/Region Niobium production (Tons)
   World 69,000
1 Brazil 63,000
2 Canada 5,000
   Rest of the world 700

Uses

Common uses of niobium include :-

  • tantalum capacitors
  • steel alloys
  • tantalum plating
  • arc welding
  • super conductive research
  • Medicine
  • Jewelry

 

Uses

Uses of Niobium

  1.  Niobium is used in making superconductive magnets owing to its superconductive properties. These magnets are in the form of niobium zirconium (Nb-Zr) wires. Hope exists that one day this Nb-Zr wire could direct large scale power generation.
  2. Ladies, guess what? Niobium is also used in making jewellery. So be on the lookout for them next time you are at a gem store. Just ask the seller form some niobium navel rings!

    Navel rings
    Navel rings
  3. Niobium is also used in making steel alloys together with other elements. These super alloys are then used in making of jet engines and heat resistant equipemnt. Hey Kenya, can we now start making jets then? Engine parts from Kwale and body from Crater Body Works. Vroom.

 

Summary Table.

Niobium Product Application Technical Attributes/Benefits
HSLA Ferro-niobium (~60%Nb) Niobium additive to ‘high strength low alloy’ steel and stainless steel for oil and gas pipelines, car and truck bodies, architectural requirements, tool steels, ships’ hulls, railroad tracks. Imparts a doubling of strength and toughness due to grain refining. Weight reduction.
Niobium oxide – Manufacture lithium niobate for surface acoustic wave filters.
– Camera lenses.
– Coating on glass for computer screens.
– Ceramic capacitors.
– High index of refraction.
– High dielectric constant.
– Increase light transmittance.
Niobium carbide Cutting tool compositions. High temperature deformation, controls grain growth.
Niobium powder Niobium capacitors for electronic circuits. High dielectric constant, stability of oxide dielectric.
Niobium metal plates, sheets, wire, rod, tubing – Sputtering targets.
– Cathode protection systems for large steel structures.
– Chemical processing equipment.
Corrosion resistance, formation of oxide and nitride films. Increase in high temperature resistance and corrosion resistance, oxidation resistance, improved creep resistance, reduced erosion at high temperatures.
Niobium-titanium alloy
Niobium-tin alloy
Superconducting magnetic coils in magnetic resonance imagery (MRI), magnetoencephalography, magnetic levitation transport systems, particle physics experiments. Electrical resistance of alloy wire drops to virtually zero at or below temperature of liquid helium (-268.8°C).
Niobium-1%zirconium alloy – Sodium vapor lamps
– Chemical processing equipment
Corrosion resistance, fixation of oxygen, resistance to embrittlement.
Vacuum-grade ferro-niobium and nickel-niobium Superalloy additions for turbine blade applications in jet engines and land-based turbines. Inconel family of alloys, superalloys. Increase in high temperature resistance and corrosion resistance, oxidation resistance, improved creep resistance, reduced erosion at high temperatures.

 

Wallpaper

Summary

 

In summary, niobium has some pretty cool uses and now that it is about to be mined in Kenya, we should expect some export revenue pretty soon. Seeing that not many produce this element, Kenya is set to be among the top producers for this element.

Did you learn some thing new about niobium? Let us know in the comments below. Also share, like and repost this article to share the knowledge.

 

Sources

Post author

The RocKe Scientist is an award winning earth science platform based in Kenya.

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