- Summary-----------------------
Access
to lanthanide files
-
- On this page :
- - Lanthanides and
compounds, classification and properties
-
- - Principal rare earth
ores
-
- - Colouring
pigments for ceramic wares containing
lanthanides
-
- - Effects on
the properties of glazes
-
- - Prices of oxides and
compounds of rare earths
-
 French
version-
Article translated by :
- Edouard Bastarache
- Sorel-Tracy
- Quebec
- edouardb@colba.net
-
-
|
LANTHANIDES
and Ceramics
By
Smart2000
|
-
-
-
- LANTHANIDES
and COMPOUNDS, classification and properties :
-
Lanthanides, also called
"rare earths", are the 15 elements going from n°
57 to 71 in the periodic classification of elements.
- (the atomic molar mass of
the these elements, ranging between 138.91 and 174.97,
is very high).
- The lanthanide oxides have
very high melting points, which makes them stable in
the majority of the ceramic glazes.
-
-
|
Element or
compound
|
Atomic Number
|
Symbol / Formula
|
Molar Mass
|
T°C Fusion
|
T°C Boiling
|
|
Lanthanum
|
57
|
La
|
138.91
|
920
|
3469
|
|
Oxide of
Lanthanum III
|
-
|
La2O3
|
325.81
|
-
|
-
|
|
Cerium
|
58
|
Ce
|
140.12
|
797
|
3443
|
|
Oxide of Cerium
III
|
-
|
Ce2O3
|
328.2
|
1687
|
-
|
|
Oxide of Cerium
IV
|
-
|
CeO2
|
172.1
|
1950
|
-
|
|
Phosphate of
Cerium
|
-
|
CePO4
|
253.3
|
-
|
-
|
|
Sulfate of Cerium
III
|
-
|
Ce2(SO4)3
|
568.8
|
-
|
-
|
|
Sulfate of cerium
IV
|
-
|
Ce(SO4)2
|
332.2
|
-
|
-
|
|
Praseodymium
|
59
|
Pr
|
140.907
|
930.8
|
3511.8
|
|
Oxide of
Praseodymium III
|
-
|
Pr2O3
|
329.81
|
2300
|
-
|
|
Oxide of
Praseodymium IV
|
-
|
PrO2
|
172.91
|
-
|
-
|
|
Black Oxide of
Praseodymium
|
-
|
Pr6O11
|
1021.46
|
-
|
-
|
|
Neodymium
|
60
|
Nd
|
144.24
|
1021
|
3074
|
|
Oxide of
Neodymium III
|
-
|
Nd2O3
|
336.48
|
2320
|
-
|
|
Prometheum
|
61
|
Pm
|
147.00
|
1100
|
3000
|
|
Oxide of
Prometheum III
|
-
|
Pm2O3
|
342.00
|
-
|
-
|
|
Samarium
|
62
|
Sm
|
150.35
|
1074
|
1794
|
|
Oxide of Samarium
II
|
-
|
SmO
|
166.35
|
-
|
-
|
|
Oxide of Samarium
III
|
-
|
Sm2O3
|
348.70
|
2335
|
-
|
|
Europium
|
63
|
Eu
|
151.96
|
822
|
1529
|
|
Oxide of Europium
II
|
-
|
EuO
|
167.96
|
-
|
-
|
|
Oxide of Europium
III
|
-
|
Eu2O3
|
351.92
|
2350
|
-
|
|
Gadolinium
|
64
|
Gd
|
157.25
|
1313
|
3273.8
|
|
Oxide of
Gadolinium III
|
-
|
Gd2O3
|
362.5
|
2420
|
-
|
|
Terbium
|
65
|
Tb
|
158.92
|
1356
|
3230
|
|
Oxide ofTerbium
III
|
-
|
Tb2O3
|
365.85
|
2410
|
-
|
|
Oxide of Terbium
IV
|
-
|
TbO2
|
190.93
|
-
|
-
|
|
Dysprosium
|
66
|
Dy
|
162.50
|
1411
|
2573
|
|
Oxide of
Dysprosium III
|
-
|
Dy2O3
|
373.08
|
2408
|
-
|
|
Holmium
|
67
|
Ho
|
164.94
|
1470
|
2720
|
|
Oxide of Holmium
III
|
-
|
Ho2O3
|
377.88
|
2415
|
-
|
|
Erbium
|
68
|
Er
|
167.26
|
1529
|
2868
|
|
Oxide of Erbium
III
|
-
|
Er2O3
|
382.52
|
2418
|
-
|
|
Thullium
|
69
|
Tm
|
168.93
|
1545
|
1950
|
|
Oxide of Thullium
II
|
-
|
TmO
|
184.94
|
-
|
-
|
|
Oxide of Thullium
III
|
-
|
Tm2O3
|
385.87
|
2425
|
-
|
|
Ytterbium
|
70
|
Yb
|
173.04
|
824
|
1196
|
|
Oxide of
Ytterbium II
|
-
|
YbO
|
189.04
|
-
|
-
|
|
Oxide of
Ytterbium III
|
-
|
Yb2O3
|
394.08
|
2435
|
-
|
|
Lutecium
|
71
|
Lu
|
174.97
|
1663
|
3402
|
|
Oxide of Lutecium
III
|
-
|
Lu2O3
|
206.97
|
2490
|
-
|
-
- Carbonated compounds are
also available on the market.
-
- Non-lanthanide
elements and compounds associated with RARE EARTHS:
-
-
|
Element or
compound
|
Atomic number
|
Symbol / Formula
|
Molar Mass
|
T°C
Fusion
|
T°C
Boiling
|
|
Yttrium
|
39
|
Y
|
88.906
|
-
|
-
|
|
Oxide of Yttrium
III
|
-
|
Y2O3
|
225.81
|
2439
|
-
|
|
Scandium
|
21
|
Sc
|
44.956
|
-
|
-
|
|
Oxide of Scandium
III
|
-
|
Sc2O3
|
137.91
|
2485
|
-
|
-
-
- PRINCIPAL
RARE EARTH ORES:
-
1) MONAZITE
:
-
- Monazite is an igneous rock,
it is a rare earth phosphate of the (Ce, La,Y,
Nd,…Th)PO4 type. It is one of the basic minerals
for the extraction of lanthanides, it is also the most
widespread on our planet. It is associated with
granites, pegmatites and also present in gneisses and
carbonites. Its great chemical resistance enables it
to be present in a form concentrated in detrital
sands. Thus it is generally exploited for thorium (Th,
radioactive actinide), cerium (Ce), and lanthanum
(La). These phosphates are classified in several types
of Monazites according to the dominant lanthanide,
with mainly Ce-Monazite (Ce, La, Nd, Th, Y)PO4,
La-Monazite (La, Ce, Nd)PO4, Nd-Monazite (Nd,
La,Ce)PO4.
- Other traces of elements
such as dysprosium (Dy), gadolinium (Gd), praseodymium
(Pr), lutecium (Lu), holmium (Hm), erbium (Er),
thulium (Tm), ytterbium (Yb), samarium (Sm) and other
lanthanides are also present in this type of ore. The
name Monazite comes from the Greek, Monazein, which
means "being alone", by the fact that the first
Monazite crystals discovered were very isolated in
pegmatic rocks containing complex phosphates. There
are very significant Monazite deposits in India,
Brazil, Idaho and Florida (USA), South
Africa.
-
- Monazite is radioactive,
sometimes strongly, it often contains Thorium.
-
- It is mainly the extraction
and the refining of thorium from Monazite ore which
allows the recovery of associated lanthanides. The
separation of lanthanides between them is done by
chemical means, yttrium is also found, it is not a
part of lanthanides but it is classified all the same
as a "rare earth" because of its physical and chemical
analogy. Raw Monazite contains approximately 50 %
cerium, 25% lanthanum, 15% neodymium and 10% of other
rare earths.
-
- 2) BASTNAESITE
:
-
- It is an anhydrous natural
carbonate of (La, Ce) (CO3) F type or the (Y, Ce)
(CO3)F type discovered in Russia in 1969. It contains
as impurities traces of Neodymium (Nd), Praseodymium
(Pr) and also Thorium (Th, radioactive).
-
- Other ores:
-
- - Allanite, (Allanite (Ce) :
(Ce, Ca, Y)2(Al, Fe+2, Fe+3)3 (SiO4)3 OH; Allanite (Y)
:
- -
(Y,Ce,Ca)2(Al,Fe+3)3(SiO4)3 OH)
- - Fergusonite, (Fergusonite
(Ce) : (Ce,La,Nd)NbO4 ; Fergusonite (Nd) :
(Nd,Ce)NbO4)
- - Gadolinite, (Gadolinite
(Ce) : (Ce,La,Nd,Y)2Fe+2Be2SiO10)
- - Lanthanite, (Lanthanite
(Ce) : (Ce,La,Nd)2(CO3)3.8H2O ; Lanthanite (Nd) :
- - (Nd,La)2(CO3)3.8H2O)
- - Samarskite, (Samarskite
(Y) : (Y,Ce,U,Fe+2)3(Nb,Ta,Ti)5O16)
- - Cerite
- - Xenotime
- - Euxenite
-
- Didymium :
indicates a mixture of praseodymium and
neodymium or a rare earth without cerium. This
compound can be used as a colourant, it roughly
contains lanthanum 50%, neodymium 25% and praseodymium
10%
-
- Principal places of
extraction of rare earth ores: Australia, China,
Mongolia, India, Brazil, the United States of America,
Malaysia, Russia, Tanzania, Burundi, Zambia,
Madagascar, Norway and Sweden.
-
- NOTE: As one can note
it, these ores are very complex and contain
radioactive elements (Th) in variable amounts. The
purity of commercial oxides obtained from these ores
requires extreme effectiveness in the operations of
separation and requires a very precise quality
control. This explains more the high price of these
materials than the fact of their be-saying scarcity.
- A. Peltier (Research centre
of the INRS - France) quoted in 1986: "cerium is as
abundant in the earth's crust as copper, lanthanum and
neodymium are more widespread than lead and the rarest
element of the family of lanthanides, terbium, is more
widespread than money! ".
-
- COLOURING
STAINS for lanthanide-coloured ceramic wares
:
-
- They are mainly stains based
on zircon (ZrSiO4) characterized by their high
chemical and thermal strength.
-
- One finds among these
colouring stains the following associations :
-
- Zircon - Cerium (ZrSiO4 -
CeO2) - Light yellow colour
- Zircon - Praseodymium
(ZrSiO4 - Pr6O11 *) - Yellow
- Zircon - Terbium (ZrSiO4 -
Tb4O7) - Yellow
- Zircon - Neodymium (ZrSiO4 -
Nd2O3) - Mauve
- Zircon - Dysprosium (ZrSiO4
- Dy4O3) - Yellow
-
- As well as lanthanide
combinations such as Zircon-Cerium-Praseodymium or
Zircon-Cerium-Neodymium…. associations generally
containing cerium.
-
- These pigments are
opacifying agents because their high chemical strength
keeps them as coloured particles suspended in glazes.
-
- (*) Pr6O11: black oxide of
praseodymium obtained by calcination with air.
-
-
- EFFECTS ON
THE PROPRIETES OF GLAZES :
-
- Lanthanides belong to a
group of elements with very close characteristics,
their behaviour in glazes resembles each other.
-
- Effect on fusibility :
-
- Their oxides have identical
forms and melting points relatively high between
2200°C and
- 2500 °C which gives
them very great chemical resistance. Despite
everything, they rather strongly support the
fusibility of glazes and can in certain cases replace
the alkaline oxides and boron.
-
- Effect on the density
:
-
- Lanthanides are very heavy,
they increase the density of glazes. Which improves
their index of refraction.
-
- Effect on thermal
dilatation :
-
- Weak influence on the
dilatation coefficient.
-
- Effect on viscosity :
-
- The effect of lanthanides on
the lowering of viscosity of glazes is rather
significant, but for amounts rather high and higher
than 10% by weight.
-
- Effect on elasticity :
-
- Weak influence on this
property.
-
- Effect on chemical
resistance :
-
- Generally, they improve
chemical resistance of glazes.
-
- Experience with
lanthanides in Ceramics :
-
- The broadest experience with
lanthanides in ceramic glass and glazes rests mainly
on cerium which has been for a long time the most
often used.When one introduces cerium oxide CeO2 into
glazes, this one can form two kinds of oxides: CeO2
dioxide of cerium and Ce2O3 trioxyde of cerium. The
ratio of the types of oxides obtained depends on the
cerium content and the conditions of firing
(temperature, atmosphere and speed of cooling), it has
an influence on the development of the colour of the
glaze.
-
- The more significant the
amount of cerium, the more Ce2O3 is present.
- Balance of the two types of
oxides in glazes : 4 CeO2 <-----> 2 Ce2O3 +
O2
- CeO2 is a powerful oxidizer
in glazes and glasses, one also uses it for its
"bleaching" properties on impurities such as FeO.
- Cerium forms two oxides,
CeO2 and Ce2O3 which is not stable in the air.
- It is the CeO2 form that
is marketed.
-
- Dichroism:
-
Glazes coloured by lanthanides
present an effect of dichroism which enables them to
appear coloured in one way in daylight and in another in
artificial light. This effect is marked the most for
colouring materials containing neodymium and
praseodymium. It depends on the thickness of the glaze
and its rare earth concentration.
Glazes coloured by neodymium can
be blue in daylight and appear purplish-pink under
lighting of incandescent lamps. The combination of
neodymium and other rare earths such as cerium or
praseodymium allows very spectacular effects in this
field. The addition of other "ordinary" oxides such as
cobalt or nickel increases furthermore the possibilities.
-
- Fluorescence
:
-
- An effect of fluorescence
accompanies the majority of glazes coloured by
lanthanides, generally rather weak. It depends
primarily on the composition of the glaze.
-
- Colouring of the
glazes :
-
- The three principal
lanthanide oxides used to produce colours in ceramics
are:
-
- - praseodymium
(greens)
- - neodymium (blue to mauve
in daylight)
- - cerium (yellows and
browns)
- The colours obtained are
light and vivid (fluo tones).
-
- Erbium oxide added to glass
or glazes gives candy pink colours.
-
- Titanium-Cerium Yellow
: colouring due to the formation of cerium
titanate with the introduction of the oxides CeO2 and
TiO2 to a total value of 3% for each one, the
intensity grows with the increase in titanium.
-
- Colouring with
Cerium-Vanadium : green colour in artificial
lighting and pink in daylight (Dichroic effect).
-
- Purple with neodymium
: colouring obtained by the additions of about 1
to 3 % with purplish red dichroic effect in artificial
lighting and blue purple in daylight.
-
- Praseodymium green
: a "lime" colour characteristic of this oxide
with amounts from 0.5 to 1.5%
-
- For the colouring of
porcelain in yellow and green colours resistant to
fire and stable with respect to light, one uses
praseodymium carbonate (Pr2(CO3)3.8H2O) or
praseodymium chloride. According to the intensity of
the color, one mixes it with cerium oxide.
-
-
- PRICES of
oxides and compounds of RARE EARTHS :
-
- Are indicated here, the main
compounds of rare earths used in glass or ceramic
glazes colouring. They are rather expensive products,
and one should not hesitate to consult many suppliers
because many charge too much for these products, which
makes them unaffordable for many and slows down
considerably the development of creation in the field
of ceramics….
-
- It can be also more
economical to choose qualities of products with a
lower degree of purity, the result not being
inevitably better with too pure products with regard
to colouring effects.
-
- Some prices obtained
from suppliers of French and American chemicals :
-
- (Prices in 2003
! before tax, departure, retail prices in
France by a supplier of chemicals, retail prices in
the USA by a retailer of ceramic raw materials, note
that the prices per kg are quite cheaper in the USA
for ceramists eager to discover colourings with
lanthanide oxides)
-
-
|
Compound
|
Purity
|
Quantity
|
Price in
France
|
Price in the USA
|
|
Cerium oxide CeO2
|
96%
|
25 g
|
25.00 Euros for 25g
|
-
|
|
Cerium oxide CeO2
|
99.5%
|
100 g
|
105.00 Euros for
100g
|
-
|
|
Cerium oxide CeO2
|
99%
|
1 kg
|
140.00 Euros per kg
|
-
|
|
Cerium oxide CeO2
|
99%
|
20 kg
|
12.50 Euros per kg
|
-
|
|
Black Praseodymium
oxide Pr6O11
|
99.9%
|
25 g
|
30.00 Euro for 25g
|
$ 22.00 for 25g
|
|
Black Praseodymium
oxide Pr6O11
|
96%
|
250 g
|
55.00 Euros for 250g
|
$ 18.50 for 250g
|
|
Black Praseodymium
oxide Pr6O11
|
97.5%
|
1 kg
|
140.00 Euros per kg
|
$ 48.50 per kg
|
|
Black Praseodymium
oxide Pr6O11
|
97.5%
|
20 kg
|
15.00 Euros per kg
|
$ 40.50 per kg
|
|
Praseodymium
carbonate
|
95%
|
1 kg
|
145.00 Euros per kg
|
-
|
|
Praseodymium
carbonate
|
95%
|
20 kg
|
15.00 Euros per kg
|
-
|
|
Neodymium oxide III
(Nd2O3)
|
99%
|
25 g
|
23.00 Euros for 25g
|
$ 25.00 for 25g
|
|
Neodymium oxide III
(Nd2O3)
|
99.9%
|
50 g
|
57.00 Euros for 50g
|
$ 50.30 for 50g
|
|
Neodymium oxide III
(Nd2O3)
|
95%
|
1 kg
|
156.00 Euros per kg
|
$ 55.33 per kg
|
|
Neodymium oxide III
(Nd2O3)
|
95%
|
20 kg
|
26.00 Euros per kg
|
$ 46.25 per kg
|
|
Neodymium carbonate
|
95%
|
1 kg
|
152.00 Euros per kg
|
-
|
|
Neodymium carbonate
|
95%
|
20 kg
|
21.00 Euros per kg
|
-
|
|
Erbium oxide III
(Er2O3)
|
99%
|
25 g
|
78.00 Euros for 25g
|
$ 39.00 for 25g
|
|
Erbium oxide III
(Er2O3)
|
96%
|
1 kg
|
175.00 Euros per kg
|
$ 85.00 per kg
|
|
Erbium oxide III
(Er2O3)
|
96%
|
20 kg
|
43.00 Euros per kg
|
$ 72.00 per kg
|
|
Yttrium oxide III
(Y2O3)
|
99.9%
|
1 kg
|
170.00 Euros per kg
|
-
|
|
Yttrium oxide III
(Y2O3)
|
99.9%
|
20 kg
|
42.00 Euros per kg
|
-
|
-
-
- Smart2000.fr
©
Février
2003
-
FRANCE
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et documenté par le propriétaire du site
// Contact : Smart2000@wanadoo.fr
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-
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