Listing description
Ruthenium (
/ruːˈθiːniəm/ roo-THEE-nee-əm) is the chemical element with the atomic number 44, and is represented by the symbol Ru.
It is a rare transition metal of the platinum group of the periodic table; and like the other metals of the platinum
group, ruthenium is inert to most other chemicals. The Russian scientist Karl Klaus
discovered the element in 1844 and named it after Ruthenia,
the Latin word for Rus'. Ruthenium is found associated with platinum
ores. Ruthenium is a minor component in these ores and therefore is a
relatively rare element. Most ruthenium is used for wear-resistant electrical
contacts and the production of thick-film resistors. A minor application of
ruthenium is its use in some platinum alloys
Detailed description
Physical properties
A polyvalent hard
white metal, ruthenium is a member of the platinum group and is in group 8 of the periodic table:
|
26
|
iron
|
2, 8, 14, 2
|
|
44
|
ruthenium
|
2, 8, 18, 15, 1
|
|
76
|
osmium
|
2, 8, 18, 32,
14, 2
|
|
108
|
hassium
|
2, 8, 18, 32,
32, 14, 2
|
However, it has
an atypical configuration in its outermost electron shells: whereas all other
group-8 elements have 2 electrons in the outermost shell, in ruthenium, one of
those is transferred to a lower shell. (This effect can be observed in the
neighborhood of niobium (41), ruthenium (44), rhodium (45), and palladium (46))
Ruthenium has
four crystal modifications and does not tarnish at normal temperatures.
Ruthenium dissolves in fused alkalis, is not attacked by acids but is attacked
by halogens at high temperatures. Small amounts
of ruthenium can increase the hardness of platinum and palladium. The corrosion resistance of titanium is increased markedly by the addition
of a small amount of ruthenium.[3]
This metal can be
plated either by electroplating or by thermal decomposition methods.
A ruthenium-molybdenum alloy is known to be superconductive at temperatures below 10.6 K.[3]
Occurrence
Ruthenium is
exceedingly rare and is the 74th most abundant metal on Earth.[6] This element is generally found in
ores with the other platinum group metals in the Ural Mountains and in North and South America. Small
but commercially important quantities are also found in pentlandite extracted from Sudbury, Ontario, Canada, and in pyroxenite deposits in South Africa. The native ruthenium is very rare
mineral (Ir replaces part of Ru in its structure).[7][8]
Production
Mining
Ruthenium, like
the other platinum group metals, is obtained commercially as a by-product from nickel and copper mining and processing as well as by the
processing of platinum group metal ores. During electrorefining
of copper and nickel, noble
metals such as silver, gold and the platinum group metals including selenium and tellurium settle to the bottom of the cell as anode
mud, which forms the starting point for their extraction.[7][8] In order to separate the metals, they
must first be brought into solution. Several methods are available depending on
the separation process and the composition of the mixture; two representative
methods are fusion with sodium peroxide followed by dissolution in aqua regia, and dissolution in a mixture of chlorine with hydrochloric acid.[11][12] Osmium, ruthenium, rhodium and
iridium can be separated from platinum and gold and base metals by their
insolubility in aqua regia, leaving a solid residue. Rhodium can be separated
from the residue by treatment with molten sodium bisulfate. The insoluble
residue, containing Ru, Os and Ir is treated with sodium oxide, in which Ir is
insoluble, producing water-soluble Ru and Os salts. After oxidation to the
volatile oxides, RuO4 is separated from OsO4 by
precipitation of (NH4)3RuCl6 with ammonium
chloride or by distillation or extraction with organic solvents of the volatile
osmium tetroxide.[13] Hydrogen is used to reduce ammonium ruthenium chloride yielding a powder.[14]
From used nuclear fuels
Ruthenium is a
fission product of uranium-235, therefore each kilo of fission
products contains significant amounts of the lighter platinum group metals and
also ruthenium. Used
nuclear fuel
might be a possible source for ruthenium. The complicated extraction is expensive
and the also present radioactive isotopes of ruthenium would make a storage for
several half-lives of the decaying isotopes necessary. This makes this source
of ruthenium unattractive and no large-scale extraction has been started.[16][17][18]
History
Though naturally
occurring platinum, containing all six platinum
group metals,
was used for a long time by pre-Columbian Americans and known as a material to
European chemists from the mid-16th century, it took until the mid-18th century
for platinum to be identified as a pure element. The discovery that natural
platinum contained palladium, rhodium, osmium and iridium took place in the
first decade of the 19th century.[21] Platinum in alluvial sands of Russian rivers gave access to raw
material for use in plates and medals and for the minting of ruble coins, starting in 1828.[22] Residues of platinum production for
minting were available in the Russian Empire, and therefore most of the
research on them was done in Eastern Europe.
It is possible
that the Polish chemist Jędrzej
Śniadecki isolated element
44 (which he called "vestium") from platinum ores in 1807. His work
was never confirmed, however, and he later withdrew his claim of discovery. Jöns Berzelius and Gottfried Osann nearly discovered ruthenium in 1827. They examined residues that were left
after dissolving crude platinum from the Ural Mountains in aqua regia. Berzelius did not find any unusual
metals, but Osann thought he found three new metals, pluranium, ruthenium and
polinium. This discrepancy led to a long-standing controversy between Berzelius
and Osann about the composition of the residues.[24]
In 1844, the
Russian scientist Karl
Klaus showed that the
compounds prepared by Gottfried Osann contained small amounts of ruthenium,
which Klaus had discovered the same year.[21] Klaus isolated ruthenium from the
platinum residues of the rouble production while he was working in Kazan University, Kazan.[24] Klaus showed that ruthenium oxide
contained a new metal and obtained 6 grams of ruthenium from the part of
crude platinum that is insoluble in aqua regia.
The name derives
from Ruthenia, the Latin word for Rus', a historical area which includes present-day
western Russia, Ukraine, Belarus, and parts of Slovakia and Poland. Karl Klaus used the name proposed by Gottfried Osann in 1828. He chose the element's name
in honor of his birthland, as he was born in Tartu, Estonia, which was at the time a part of the Russian Empire.
PRICE
$63/TROY OZ
For more information:
mobile: +2348039721941
contact person: emeaba uche
e-mail: emeabau@yahoo.com
website: www.franchiseminerals.com
No comments:
Post a Comment