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Index



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1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

1

1
H

Raw critical materials

2
He

2

3
Li

4
Be





5
B

6
C

7
N

8
O




9
F




10
Ne

3

11
Na

12
Mg


13
Al

14
Si

15
P

16
S

17
Cl

18
Ar

4

19
K

20
Ca

21
Sc

22
Ti

23
V

24
Cr

25
Mn

26
Fe

27
Co


28
Ni

29
Cu

30
Zn

31
Ga


32
Ge


33
As

34
Se




35
Br




36
Kr

5

37
Rb

38
Sr

39
Y

40
Zr

41
Nb


42
Mo

43
Tc

44
Ru


45
Rh


46
Pd


47
Ag

48
Cd

49
In


50
Sn

51
Sb


52
Te




53
I




54
Xe

6

55
Cs

56
Ba

57
La




72
Hf

73
Ta

74
W


75
Re

76
Os


77
Ir


78
Pt


79
Au

80
Hg

81
Tl

82
Pb

83
Bi

84
Po




85
At




86
Rn

7

87
Fr

88
Ra

89
Ac




104
Rf

105
Db

106
Sg

107
Bh

108
Hs

109
Mt

110
Ds

111
Rg

112
Cn

113
Uut

114
Fl

115
Uup

116
Lv




117
Uus




118
Uuo




Lanthanides

58
Ce

59
Pr

60
Nd

61
Pm

62
Sm

63
Eu

64
Gd

65
Tb

66
Dy

67
Ho

68
Er

69
Tm

70
Yb

71
Lu

Actinides

90
Th

91
Pa

92
U

93
Np

94
Pu

95
Am

96
Cm

97
Bk

98
Cf

99
Es

100
Fm

101
Md

102
No

103
Lr




Other raw Critical materials

Coal coke

CaF2

MgCO3

Natural graphite

Phosphate rocks

Rare earth elements

Back to the index



Candini Chiara, Puggioli Christian, Radi Silvia

Germanium (Ge)

Germanium is a metal placed in IV A in the periodic table. In 1869, Dmitri Mendeleev predicted its existence and some of its properties based on its position on the periodic table. In 1886, Clemens Winkler found the new element along with silver and sulphur, in a rare mineral called argyrodite. Winkler named the element after his country, Germany 1.




Uses:

Germanium is a semiconductor and used as a transistor in thousands of electronic applications:



  • Photovoltaics (conversion of electromagnetic radiation as sunlight, into electricity);

  • Fibre optics → germanium increases refractive index;

  • Infrared vision → germanium uses its transparency to infrared reaction; mac hd 500:users:silvia:desktop:image2.jpg

  • Catalyst in organic chemistry2;


mac hd 500:users:silvia:desktop:image2.jpg


Properties
Germanium is a hard, brittle, lustrous, semi-conducting metal and is similar in chemical and physical properties to silicon.

It is also stable in air and water.



Characteristics

You can find germanium also in zinc minerals and in by-products of combustion of some coals.

Germanium minerals are very rare and are found in small quantities 3; because of this characteristic it is a critical material and it will be probably substituted by silicon in future.

A consequence is the rising back of germanium’s price (after decreasing until the middle of 2012), even higher level than before 4.


Origin

The production of germanium is about 80 tonnes per year.

China is the major producer of germanium, followed by the Ukraine and Russia5
Solutions

The 30% of the worldwide consumption comes from recycled germanium. The 80% of fibre optic scarp are recycled6 and also the 50% of germanium metal used for electronic and optic are recycled.

The best substitute of germanium is Silicon (that is also less-expensive) for some electronic applications7

References


  1. https://en.wikipedia.org/wiki/Germanium

  2. Butterman W.C., Jorgenson JD (2005) Germanium. Open-File Report 2004-1218

  3. http://www.rsc.org/periodic-table/element/32/germanium

  4. Metal Bulletin Germanium Metal Rotterdam $/Kg; Lastes Metal Prices Tracking and Comparison Toll. ( http://www.metalbulletin.com/My-price-book.html?price=42087. Accessed 3 September 2013 )

  5. Ad-hoc Working Group on defining critical raw materials (2010) Critical raw materials for the EU: European Commission

  6. Bell Labs-Lucent technology Bell Labs Innovative Germanium-Recovery Process is Economically, Enviromentally Friendly. Science Daily.

  7. Guberman, D.E. (2013) Germanium, in: U.S. Geological Survey (ed.) Mineral commodity summaries 2013


Back to the index

Candini Chiara, Puggioli Christian, Radi Silvia

Gallium

Gallium is a soft, silvery metal with symbol Ga and atomic number 31. It’s a by-product of aluminium and in its pure, solid form, it is silvery white and has a fracture pattern similar to glass.

Gallium comes from the latin name for France, Gallia. It also has origins in the Latin word gallus, a translation of Lecoq, wich means “rooster” and is also the first name of the scientist who discovered the element: Paul Emile Lecoq de Boisbaudran. The latter observed two new violet lines in the atomic spectrum of some zinc. He knew it meant that an unknown element was present, but its existence, and properties, had been predicted by Mendeleev who had left a gap below aluminium in his periodic table.

http://virtualblognews.altervista.org/wp-content/uploads/2013/04/gallio-metallo-raro.jpg


http://www.postapowerblog.com/wp-content/uploads/2016/01/asterix-.jpg

USE

The commercial use of gallium is dominated by the semiconductor applications (98%).



  • It is used to create very shiny mirrors

  • Gallium arsenide is a useful silicon substitute for the electronics industry. It is an important component of many semiconductors.

  • Thanks to its ability to convert electricity to light it is used in red LEDs (light emitting diodes). Solar panels on the Mars Exploration Rover contained gallium arsenide.

  • It has important uses in Blu-ray technology, mobile phones and pressure sensors for touch switches.

  • Gallium readily alloys with most metals. It is particularly used in low-melting alloys.




  • It has a high boiling point, so it's used for recording very high temperatures that would vaporise a thermometer.http://www.rayennur.com/wp-content/uploads/2015/05/led_rainbow_by_steeph_k-d6jb8az.jpg





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