Hello everyone. In this video
I'd like to tell you about the most recently discovered
non-radioactive metal. That is, about hafnium.
If you look at the periodic table,
You'll see that hafnium is located at the bottom of the group 4
along with zirconium and titanium.
It is there not accidentally,
because all of these free metals share common chemical properties,
especially zirconium and hafnium.
That is the reason why hafnium is usually found combined with zirconium in rocks,
for instance, in such minerals as zircon where hafnium concentration
range from one to four percent.
the striking resemblance of this element with an atomic number 72
To zirconium was the very reason why it was discovered only in
1923 it was named after Latin name of the Danish capital
hafnia.
Here you can see the reagents and also obtained metallic half-known* (Hafnium) with george de hevesy
the discoverer of this element used in his experiments
Pure extracted Hafnium is a silvery
malleable and quite heavy metal the density of which is two times that of
zirconium because of its rarity and the challenging process of separation from
Zirconium the price of one gram of Hafnium is quite high
amounting to ten dollars per gram
By the way, in the last ten years the cost of Hafnium has increased significantly because of the Fukushima nuclear disaster
after the nuclear disaster
the Japanese government
Shut down all the power stations in Japan which reduce demand for zirconium used for constructing
nuclear reactors. Since hafnium is extraction byproduct of the production of highly pure
zirconium metal
reduction in the production of zirconium led to the deficit of hafnium and thus its arch in the price.
It's a very hard to separate hafnium from zirconium because of the close resemblance of their chemical properties
that is why only
Recrystallization from hafnium chloride can be used for purpose nowadays
separation of hafnium from zirconium is a very important process because
Halep you a (High/highly pure) neutron transmission zirconium is essential for the manufacturing of fuel assembly. Hafnium on the other hand
absorbs free neutrons very well and because of that
Its traces in the zirconium tubes may interfere with the reactors work
Hafnium can be used for organizing the speed of chain reaction in
reactors and it also can be used in control rods. From a chemical point of view hafnium is almost a twin brother of
Zirconium and is not very likely to impress you with its chemical activity
This metal almost doesn't oxidize when exposed to air
but when heated up it comes in a thick dark oxide layer just like zirconium.
Like this piece cut off of a bigger chunk once did just like zirconium hafnium
produces bright sparks when wrapped (when it rasped) on a file
however
they are seen even better when a piece of hafnium is grinded against a
grinding wheel. The small particles produced burn up in the air at a very high temperature more than
2,000 Celsius degrees to be precise
Which produces very bright sparks. If hafnium powder is burnt with a burner
this process can be observed even better. When hafnium burns up in the air
what produced is nothing but hafnium oxide which can then be used to produce the most
refractory material on earth that is tantalum hafnium carbide
With the melting point more than 2,000 Celsius degrees.
In the future such materials can improve the properties of rocket engines or
increase the temperature of plasma in fusion reactors
but those are just my suggestions. Hafnium almost doesn't dissolve in concentrated nitric or
hydrochloric acids
But in hydrofluoric acid this metal starts losing its inert
properties quite quickly and similarly to titanium start dissolving very quickly forming a complex compound
that is, hydrogen-hexafluora-titanate to be precise. And yes
I'm running this reaction in a plastic cup because hydrofluoric acid will damage a glass one.
During this reaction dark oxide layer disappears of the surface of the metal which makes the hafnium exposed shiny again.
Upon ageing of alkali to a solution of hafnium complex a white precipitate of calcium hydroxide
will form because almost all hafnium compounds have white color just like
Zirconium hafnium fits well for running color anodizing the processes and can produce
beautiful and quite expensive Geralyn
Nowadays hafnium is mainly used for
manufacturing control rods in some nuclear reactors
Mostly those are research and military models for
This metal is also added to the heat-resistant alloys, for instance to those used to manufacture rocket engine nozzles.
It is quite expensive to use hafnium for other purposes. That is why whenever possible
It is substituted by the cheaper zirconium. Modern nuclear physicists also are tied (trying) to discover another
extraordinary application of isotope of hafnium 178
They think is
Excited atoms of this isotope can also emit X and gamma radiation
under the influence of external
forces for instance
Such as alpha rays just like luminal force emit visible light under the influence of high-energy UV rays
If a piece of hafnium 178
is exposed to the radiation
this isotope will unleash radiation, which is 100 times more efficient than
a chemical reactions. This process can help create extremely efficient nuclear reaction engines
and also more precise radiometric devices.
Since I am not very good in nuclear physics and I can make mistakes
I will leave a link to an article about this topic in the description.
Finally we can say that hafnium is a very unique and interesting metal. However due to its high price
It is not very common in our everyday life. For the provided hafnium and zirconium
pieces I'll thank the company Stanford Advanced Materials. I'll put a link to their site in the video description
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