# Patent

## Title
Saline soluble inorganic fibres

## Abstract

Thermal insulation is provided for use in applications requiring continuous resistance to temperatures of 1260° C. without reaction with alumino-silicate firebricks, the insulation comprises fibers having a composition in wt %

    
    
        65%<SiO2<86%
        MgO<10%
        14%<CaO<28%
        Al2O3<2%
        ZrO2<3%
        B2O3<5%
        P2O5<5%
        72%<SiO2+ZrO2+B2O3+5*P2O5 
        95%<SiO2+CaO+MgO+Al2O3+ZrO2+B2O3+P2O5 

Addition of elements selected from the group Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y or mixtures thereof improves fiber quality and the strength of blankets made from the fibers.

## Background
This invention relates to saline soluble, non-metallic, amorphous, inorganic oxide, refractory fibrous materials. The invention particularly relates to glassy fibres having silica as their principal constituent.
Inorganic fibrous materials are well known and widely used for many purposes (e.g. as thermal or acoustic insulation in bulk, mat, or blanket form, as vacuum formed shapes, as vacuum formed boards and papers, and as ropes, yarns or textiles; as a reinforcing fibre for building materials; as a constituent of brake blocks for vehicles). In most of these applications the properties for which inorganic fibrous materials are used require resistance to heat, and often resistance to aggressive chemical environments.
Inorganic fibrous materials can be either glassy or crystalline. Asbestos is an inorganic fibrous material one form of which has been strongly implicated in respiratory disease.
It is still not clear what the causative mechanism is that relates some asbestos with disease but some researchers believe that the mechanism is mechanical and size related. Asbestos of a critical size can pierce cells in the body and so, through long and repeated cell injury, have a bad effect on health. Whether this mechanism is true or not regulatory agencies have indicated a desire to categorise any inorganic fibre product that has a respiratory fraction as hazardous, regardless of whether there is any evidence to support such categorisation. Unfortunately for many of the applications for which inorganic fibres are used, there are no realistic substitutes.
Accordingly there is a demand for inorganic fibres that will pose as little risk as possible (if any) and for which there are objective grounds to believe them safe.
A line of study has proposed that if inorganic fibres were made that were sufficiently soluble in physiological fluids that their residence time in the human body was short; then damage would not occur or at least be minimised. As the risk of asbestos linked disease appears to depend very much on the length of exposure this idea appears reasonable. Asbestos is extremely insoluble.
As intercellular fluid is saline in nature the importance of fibre solubility in saline solution has long been recognised. If fibres are soluble in physiological saline solution then, provided the dissolved components are not toxic, the fibres should be safer than fibres which are not so soluble. The shorter the time a fibre is resident in the body the less damage it can do. H. F{umlaut over (r)}ster in ‘The behaviour of mineral fibres in physiological solutions’ (Proceedings of 1982 WHO IARC Conference, Copenhagen, Volume 2, pages 27–55(1988)) discussed the behaviour of commercially produced mineral fibres in physiological saline solutions. Fibres of widely varying solubility were discussed.
International Patent Application No. WO87/05007 disclosed that fibres comprising magnesia, silica, calcia and less than 10 wt % alumina are soluble in saline solution. The solubilities of the fibres disclosed were in terms of parts per million of silicon (extracted from the silica containing material of the fibre) present in a saline solution after 5 hours of exposure. The highest value revealed in the examples had a silicon level of 67 ppm. In contrast, and adjusted to the same regime of measurement, the highest level disclosed in the F{umlaut over (r)}ster paper was equivalent to approximately 1 ppm. Conversely if the highest value revealed in the International Patent Application was converted to the same measurement regime as the F{umlaut over (r)}ster paper it would have an extraction rate of 901,500 mg Si/kg fibre—i.e. some 69 times higher than any of the fibres F{umlaut over (r)}ster tested, and the fibres that had the highest extraction rate in the F{umlaut over (r)}ster test were glass fibres which had high alkali contents and so would have a low melting point. This is convincingly better performance even taking into account factors such as differences in test solutions and duration of experiment.
International Patent Application No. WO89/12032 disclosed additional fibres soluble in saline solution and discusses some of the constituents that may be present in such fibres.
European Patent Application No. 0399320 disclosed glass fibres having a high physiological solubility.
Further patent specifications disclosing selection of fibres for their saline solubility include for example European 0412878 and 0459897, French 2662687 and 2662688, PCT WO86/04807, WO90/02713, WO92/09536, WO93/22251, WO94/15883, WO97/16386 and U.S. Pat. No. 5,250,488.
The refractoriness of the fibres disclosed in these various prior art documents varies considerably and for these alkaline earth silicate materials the properties are critically dependent upon composition.
WO94/15883 disclosed a number of fibres that are usable as refractory insulation at temperatures of up to 1260° C. or more. These fibres comprised CaO, MgO, SiO2, and optionally ZrO2 as principal constituents. Such fibres are frequently known as CMS (calcium magnesium silicate) or CMZS ((calcium magnesium zirconium silicate) fibres. WO94/15883 required that any alumina present only be in small quantities.
A drawback found in use of these fibres, is that at temperatures between about 1300° C. and 1350° C. the fibres undergo a considerable increase in shrinkage. Typically, shrinkages increase from about 1–3% at 1200° C.; to, say, 5% or more at 1300° C.; to >20% at 1350° C. This means that, for example, a temperature overrun on a furnace can result in damage to the insulation and hence to the furnace itself.
A further drawback is that calcium magnesium silicate fibres can react with, and stick to, alumina containing materials due to formation of a eutectic composition. Since aluminosilicate materials are widely used this is a major problem.
WO97/16386 disclosed fibres that are usable as refractory insulation at temperatures of up to 1260° C. or more. These fibres comprised MgO, SiO2, and optionally ZrO2 as principal constituents. As with WO94/15883, this patent required that any alumina present only be in small quantities.
While these fibres do not show the dramatic change in shrinkage evident in the fibres of WO94/15883, they do show a significantly higher shrinkage at normal use temperatures typically having a shrinkage of 3–6% over the range 1200° C.–1450° C. These fibres do not appear to have the drawback of reacting with and sticking to alumina containing materials, however they tend to be difficult to make.
SUMMARY OF THE INVENTION
The applicants have invented a group of fibres that have a lower shrinkage across a range of temperatures than the fibres of WO97/16386, while having a higher onset of increase in shrinkage, and a more gentle change in shrinkage, than the fibres of WO94/15883 and which also have a reduced tendency to react with and stick to alumina.
Accordingly, the present invention provides thermal insulation for use in applications requiring continuous resistance to temperatures of 1260° C. without reaction with alumino-silicate firebricks, the insulation comprising fibres having a composition in wt %

    
    
        65%<SiO2<86%
        MgO<10%
        14%<CaO<28%
        Al2O3<2%
        ZrO2<3%
        B2O3<5%
        P2O5<5%
        72%<SiO2+ZrO2+B2O3+5*P2O5 
        95%<SiO2+CaO+MgO+Al2O3+ZrO2+B2O3+P2O5.
    
    


A preferred range of compositions is:

    
    
        72%<SiO2<80%
        18%<CaO<26%
        0%<MgO<3%
        0%<Al2O3<1%
        0%<ZrO2<1.5%
        98.5%<SiO2+CaO+MgO+Al2O3+ZrO2+B2O3+P2O5.
    
    


A still more preferred range has the composition:

    
    
        72%<SiO2<74%
        24%<CaO<26%
    
    


Additionally, the applicants have found that addition of small amounts of lanthanide elements, particularly lanthanum, improves the quality of the fibres, particularly their length and thickness, such that improved strength results. There is a trade-off in terms of slightly lower solubility, but the improved strength is of help, particularly in making such products as blankets, in which the fibres are needled to form an interlocking web of fibres.
Accordingly, the present invention comprises a silicate fibre comprising:

    
    
        65%<SiO2<86%
        MgO<10%
        14%<CaO<28%
        Al2O3<2%
        ZrO2<3%
        B2O3<5%
        P2O5<5%
        72%<SiO2+ZrO2+B2O3+5*P2O5 
        95%<SiO2+CaO+MgO+Al2O3+ZrO2+B2O3+P2O5.
        0.1%<R2O3<4%

where R is selected from the group Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y or mixtures thereof.

    
    


The preferred elements are La and Y. Preferably, to achieve significant improvements in fibre quality, the amount of R2O3 is greater than 0.25%, more preferably >0.5%, and still more preferably >1.0%. To minimise the reduction is solubility that occurs, the amount of R2O3 is preferably <2.5%, still more preferably <1.5% by weight. Very good results are obtained for a fibre having the composition in wt %:
















SiO2:-
73 ± 0.5%



CaO:-
24 ± 0.5%



La2O3:-
1.3–1.5%



Remaining components:-
<2%, preferably <1.5%













BRIEF DESCRIPTION OF DRAWINGS
Further features of the invention will become apparent from the claims in the light of the following illustrative description and with reference to the drawing
FIG. 1 which is a graph of shrinkage against temperature of some fibres according to the present invention in comparison with some commercial fibres.



DETAILED DESCRIPTION OF INVENTION
The inventors produced a range of calcium silicate fibres using an experimental rig in which a melt was formed of appropriate composition, tapped through a 8–16 mm orifice, and blown to produce fibre in a known manner. (The size of the tap hole was varied to cater for the viscosity of the melt—this is an adjustment that must be determined experimentally according to the apparatus and composition used).
The fibres were tested and the results for fibres that are predominantly calcium silicate fibres with some MgO are shown in Table 1, in which:

    
    
        shrinkage figures are shown as measured on a preform of fibre by the method (see below),
        compositions are shown as measured by x-ray fluorescence with boron by wet chemical analysis,
        total solubility in ppm of the major glass components after a 24 hour static test in a physiological saline solution is shown,
        specific surface area in m2g,
        a qualitative assessment of fibre quality,
        and an indication of whether the preform stuck to an aluminosilicate brick (JM 28 bricks obtainable from Thermal Ceramics Italiana and having an approximate composition 70 wt % alumina and 30 wt % silica)
    
    


The shrinkage was measured by the method of manufacturing vacuum cast preforms, using 75 g of fibre in 500 cm3 of 0.2% starch solution, into a 120×65 mm tool. Platinum pins (approximately 0.1–0.3 mm diameter) were placed 100×45 mm apart in the 4 corners. The longest lengths (L1 & L2) and the diagonals (L3 & L4) were measured to an accuracy of ±5 μm using a travelling microscope. The samples were placed in a furnace and ramped to a temperature 50° C. below the test temperature at 300° C./hour and ramped at 120° C./hour for the last 50° C. to test temperature and left for 24 hours. On removal from the furnace the samples were allowed to cool naturally. The shrinkage values are given as an average of the 4 measurements.
The inventors found that those fibres having a silica content less than 72% by weight tended to stick to the aluminosilicate brick. They also found that high MgO content fibres (>12%) did not stick (as predicted from the properties of WO97/16386).
It is known that calcium silicate fibres having an intermediate level of MgO (12–20%) stick to aluminosilicate brick, whereas magnesium silicate fibres do not. Surprisingly, for the fibres of the present invention, such intermediate levels of MgO can be tolerated. Levels of <10% MgO, or <5% MgO give the non-sticking results required, but it appears preferable for refractoriness to have a maximum level of MgO at 2.5% by weight, and more preferably the amount should be below 1.75% by weight.
Table 2 shows the effect of alumina and zirconia on these fibres. Alumina is known to be detrimental to fibre quality and the first three compositions of Table 2 have over 2% Al2O3 and stick to aluminosilicate brick. Additionally, increased alumina leads to lowered solubility. Accordingly, the inventors have determined 2% as the upper limit for alumina in their inventive compositions.
In contrast zirconia is known to improve refractoriness and Table 2 shows that silica levels of below 72% can be tolerated if the amount of ZrO2 is sufficient that the sum of SiO2 and ZrO2 is greater than 72% by weight. However, increasing zirconia lowers the solubility of the fibres in physiological saline solution and so the preferred level of ZrO2 is less than 3%.
The effect of some other common glass additives is indicated by Table 3, which shows the effect of P2O5 and B2O3 as glass forming additives. It can be seen that P2O5 has a disproportionate effect on the sticking properties of these compositions, as fibres with as low as 67.7% SiO2 do not stick to aluminosilicate brick.
B2O3 also has an effect with fibres having as low as 70.9% SiO2 not sticking. The inventors have determined that sticking to aluminosilicate brick tends not to occur for fibres meeting the relationship:

    72%<SiO2+B2O3+ZrO2+5*P2O5.


The inventors have assumed a maximum level for B2O3 and P2O5 of 5% by weight each.
Tables 1 to 3 show that minor amounts of other components may be included and the invention tolerates up to 5% of other ingredients, but preferably these other ingredients amount to less than 2%, more preferably less than 1%, since such other ingredients tend to make the fibres less refractory. (But see below for effect of specific lanthanide additives).
The above results were obtained on an experimental rig, with all of the uncertainties that entails. Production trials of the most favourable appearing fibres were conducted on two separate sites to allow both blowing and spinning of the compositions to be tried. Table 4 shows a selection of the results obtained (duplicates omitted) and shows that a very usable fibre results. The fibres tested in the production trials had compositions falling in the approximate range

    72%<SiO2<80%
    18%<CaO<26%
    0%<MgO<3%
    0%<Al2O3<1%
    0%<ZrO2<1.5%

with 98.5%<SiO2+CaO+MgO+Al2O3+ZrO2+B2O3+P2O5.



It can be seen that the compositions with an MgO level of greater than 1.75% tended to have a higher shrinkage at 1350° C. than those with a lower MgO level.
FIG. 1 shows in graphical form an important feature of the fibres of the invention and compares the shrinkage characteristics of the first three fibres and 5th fibres of Table 4 (each referred to as SW613) with commercial fibres Isofrax® (a magnesium silicate fibre from Unifrax Corporation), RCF (a standard aluminosilicate refractory ceramic fibre), and SW607 MaxTM, SW607TM, and SW612TM (calcium magnesium silicate fibres from Thermal Ceramics Europe Limited).
It can be seen that Isofrax® and RCF have a shrinkage that is in the range 3–6% over the range 1200 to 1450° C. SW607 MaXTM, SW607TM, and SW612TM have shrinkages in the range 2..5% at 1200° C. but increase rapidly after 1300° C. The fibres of the present invention have a shrinkage of less than 2% up to 1350° C., drift up to 5–8% at 1400° C. and accelerate thereafter.
The fibres of the present invention therefore have the advantage of a lower shrinkage than magnesium silicate, commercial calcium magnesium silicate, or RCF fibres at 1300° C.; commence their increase in shrinkage at a higher temperature than commercial calcium magnesium silicate fibres; have a shallower rise in shrinkage with temperature than commercial calcium magnesium silicate fibres; and do not stick to aluminosilicate brick in the way commercial calcium magnesium silicate fibres may.
The fibres can be used in thermal insulation and may form either a constituent of the insulation (e.g. with other fibres and/or fillers and/or binders) or may form the whole of the insulation. The fibres may be formed into blanket form insulation.
A problem found with the plain calcium silicate fibres described above was that the fibres tend to be short resulting in a poor quality blanket. A means of producing better fibre for blanket was required and the applicants conducted screening tests to investigate the effect on fibre quality of the addition of other elements as additives to the composition. It was found that lanthanide elements, particularly La and Y improved fibre quality. La was determined to be the most commercially interesting element and so after this initial screening test efforts centred on investigating the effect of La.
La2O3 was used as an additive in amounts of 0–4% to a fibre comprising 73.5% SiO2 and balance CaO and minor impurities to determine the optimum amount. It was determined that addition of La2O3 improved fiberisation while not reducing refractoriness. The fibres did not react with alumina bricks. However, at the highest levels of La2O3 the solubility was reduced significantly. Accordingly a compromise level of 1.3–1.5% La2O3 was used for further tests on the fibre composition.
To check and define the optimum formulation in terms of refractoriness and fiberisation for the lanthanum containing material, a study was performed looking to the increase of silica from 67% to 78% SiO2 in a material containing 1.3% La2O3 (kept constant), balance CaO+minor impurities MgO and Al2O3.
Increasing silica increases the refractoriness of the fibre, giving lower shrinkage, higher melting point and decreases reaction with alumina at high temperature.
The best compromise between refractoriness and fiberisation was found for a composition of:
















SiO2
73%



CaO
24%



La2O3
 1.3–1.5%    



Remaining impurities (Al2O3, MgO, others)
<1.5%   










This composition was tried on production scale manufacturing blanket having the composition “With La” shown in Table 5 below.
It was confirmed that this composition produced better fibres than an La free version (“No La” in Table 5). The fibres still not reacting with alumina brick, and having good refractoriness.
Better fiberisation was observed and evaluated by looking to the tensile strength of 25 mm thick blanket having a density 128 kg/m3.











TABLE 5







OXIDES
No La
With La




















Na2O
<0.05
0.18



MgO
0.89
0.46



Al2O3
0.64
0.66



SiO2
72.9
73.2



K2O
<0.05
0.08



CaO
25.5
23.6



Fe2O3
0.11
0.14



La2O3
0
1.3



LOI 1025° C.
0.08
0.09



Total
100.1
99.7



Tensile strength
25–30
35–60



128-25 blanket (kPa)










It can be seen that the addition of only 1.3% La2O3 results in a considerable improvement in tensile strength, indicating a much improved fibre.
The applicants surmise that this effect of improving fiberisation is a viscosity or surface tension modifying effect applicable generally to alkaline earth silicate fibres, and so the invention encompasses the use of such additives generally in the amounts indicated above to improve fiberisation of alkaline earth silicate fibres.










TABLE 1









Shrinkage %/24 hrs
Composition (wt %)



















Comp.
1300° c.
1350° c.
1400° c.
1450° c.
1500° c.
1550° c.
CaO
SiO2
P2O5
Al2O3
B2O3
ZrO2





CS01/C

10.34
melted
melted


35.00
62.40

0.83


CS02/C

8.52
melted
melted


33.00
63.80

0.77




CS01/D

5.14




32.90
64.60

0.80


CS01
2.60
4.34
melted



33.80
65.00

0.80


CS10

4.25
19.51
melted


33.00
65.40

0.76


CS10 cons

4.25
14.12
melted


33.00
65.40

0.76


CS02
1.92
2.58
7.83
melted


31.90
66.50

0.77


CS02/D

3.85




31.20
66.60

0.75


CMS02
2.12
melted




18.30
66.90

0.31


CMS02/B
2.35
7.02
melted



18.30
66.90

0.31


CS03/D

11.87




28.90
69.30

0.70


CMS03
2.95
melted




16.80
69.40

0.30


CMS03/B
2.75
8.08
melted



16.80
69.40

0.30


CS15


5.67
34.47
34.02

28.00
69.70

0.61


CS04/E

2.77
11.39
21.96


28.20
69.80

0.61


CS04/E cons

2.77
7.62



28.20
69.80

0.61


CS04
1.65
0.98
3.71
30.42


28.20
69.80

0.61


CMS04
2.35
melted




16.50
70.00

0.38


CS12

2.35
9.10
31.40


26.90
70.70

0.66


CS12 cons

2.35
4.80
15.37


26.90
70.70

0.66


CS16


9.37
35.35
34.37

27.20
71.00

0.61


CS17


9.05
33.70
30.64

26.60
71.40

0.62


CS18


7.92
32.00
30.02

26.20
71.60

0.75


CS19


4.84
27.36
26.41

26.40
71.60

0.73


CMS05
2.63
melted




15.10
72.00

0.97


CMS05/B
3.31
8.11
14.10



15.10
72.00

0.97


SACM01

4.01
3.56
4.79


3.17
78.00

1.60


SACM02


3.51



5.04
76.50

1.62


SACM03

5.46
8.63
10.38


7.71
75.80

1.77


CSMg01

7.36
21.14
28.33
37.44

23.60
72.90

0.61


CSMg03

2.24
7.17
12.61


20.20
75.70

0.57


CSMg02

7.14
12.13
16.17
27.03

21.60
75.20

0.54


CSMg07

7.38
20.47



23.00
73.80

0.49


CSMg06

6.23
25.18
12.34
29.97

24.20
72.30

0.51


CSMg09

1.28
2.33



18.30
78.40

0.39


CSMg08

2.86
8.24
9.70
31.43

20.50
76.50

0.44


CSMg10

1.85
1.80



17.30
79.40

0.28


CS Fe203 01

1.94
8.72
19.79
26.24

22.60
74.40

0.57


CS Fe203 05

3.47
10.11
15.34
22.52

21.10
74.70

0.58


CS Fe203 02

1.43
3.64



21.90
74.80

0.56


CS Al 03

2.18
8.47
15.15
22.38

22.30
74.60

1.03


CS13

1.46
3.00
23.16


24.00
74.30

0.55


CS Fe203 04

1.79
9.03
14.51
19.78

21.60
74.90

0.52


CS Fe203 03

2.43
12.43
20.53
24.24

21.90
74.70

0.52


CS05
1.21
1.79
4.14
melted


26.40
72.20

0.55


CS06/E

1.56
6.03
21.81
30.16

24.00
73.90

0.52


CS06/E cons

1.56
4.02
10.54
13.75
16.96
24.00
73.90

0.52


CS Al 02

1.48
2.41
13.51
18.28

23.10
74.70

0.48


CS07/E

1.50
2.14
10.00
5.19
5.81
22.20
76.50

0.53


CS14/B

2.22
6.23



22.60
75.00

0.58


CS08/E

2.03
1.34
3.10
7.72

19.50
78.90

0.70


CS06/B


2.66
melted
12.00

24.30
75.00

0.39

















Total






Composition (wt %)
Solubility
SSA
Fibre
JM 28



















Comp.
MgO
Na2O
K2O
TiO2
Fe2O3
ZnO
ppm
m2/g
Quality
sticking







CS01/C
0.56
0.30
0.15

0.24

230.0
0.33
Coarse
Stuck



CS02/C
0.51
0.40
0.14

0.22

199.0
0.45
Coarse
Stuck



CS01/D
0.48
0.26
0.15

0.18

199.1
0.37
Coarse
Stuck



CS01
0.51
0.21


0.21

235.0
0.47
Coarse
Stuck



CS10
0.52
0.24
0.15

0.21

199.8
0.30
Coarse
Stuck



CS10 cons
0.52
0.24
0.15

0.21

199.8
0.30
Coarse
Stuck



CS02
0.49
0.31


0.20

218.0
0.59
Coarse
Stuck



CS02/D
0.46
0.25
0.14

0.20

208.1
0.42
Coarse
Stuck



CMS02
14.40
0.17


0.14

213.2
0.42
Coarse
Stuck



CMS02/B
14.40
0.17


0.14



Coarse
Stuck



CS03/D
0.44



0.19

215.0
0.54
Coarse
Stuck



CMS03
13.40
0.11


0.14

280.1

Coarse
Stuck



CMS03/B
13.40
0.11


0.14



Coarse
Stuck



CS15
0.53
0.19


0.20

241.9
0.41
Good fibre
Stuck



CS04/E
0.38
0.43
0.10

0.17

260.0
0.50
Lots of flake
Stuck



CS04/E cons
0.38
0.43
0.10

0.17

260.0
0.50
Lots of flake
Stuck



CS04
0.38
0.43
0.10

0.17

269.8
0.44
Lots of flake
Stuck



CMS04
13.10
0.12


0.13



Coarse
Stuck



CS12
0.41
0.39
0.12

0.18

211.3
0.55
Good fibre
Stuck



CS12 cons
0.41
0.39
0.12

0.18

211.3
0.55
Good fibre
Stuck



CS16
0.49
0.16


0.17

283.1
0.55
Good fibre
Stuck



CS17
0.48
0.17


0.17

228.2
0.71
Good fibre
Stuck



CS18
0.49
0.20


0.18

248.8
0.71
Good fibre
Stuck



CS19
0.48
0.21


0.19

248.2
0.63
Good fibre
Stuck



CMS05
11.40
0.23


0.12

125.2

Coarse
Stuck



CMS05/B
11.40
0.23


0.12



Coarse
Stuck



SACM01
17.00



0.21

160.0
0.37
O.K fibre
Not Stuck



SACM02
14.80
0.12


0.20

206.3
0.33
O.K fibre
Not Stuck



SACM03
13.10



0.65

170.5
0.46
O.K fibre
Not Stuck



CSMg01
2.61
0.11


0.16

223.6
0.66
Good fibre some shot
Stuck



CSMg03
2.61
0.20


0.18

231.3
0.38
Good fibre some shot
Not Stuck



CSMg02
2.59



0.14

210.6
0.63
Good fibre some shot
Stuck



CSMg07
1.81



0.17

250.1
0.42
O.k fibre
Not Stuck



CSMg06
1.79
0.13


0.18

268.1
0.53
Good fibre
Not Stuck



CSMg09
1.71



0.14

228.7
0.35
Shotty
Not Stuck



CSMg08
1.65



0.16

257.2
0.43
Good fibre
Not Stuck



CSMg10
1.61



0.15

248.3
0.22
Coarse shotty
Not Stuck



CS Fe203 01
0.72
0.23


0.44

279.9
0.49
O.k fibre
Not Stuck



CS Fe203 05
0.51
0.17


2.25

207.1
0.47
Shotty
Not Stuck



CS Fe203 02
0.50
0.22


0.65

285.5
0.30
Shotty
Not Stuck



CS Al 03
0.41
0.18


0.15


0.48
Good fibre
Not Stuck



CS13
0.39
0.17


0.17

156.0
0.56
Shotty
Not Stuck



CS Fe203 04
0.39
0.16


1.47

239.7
0.41
Good fibre
Not Stuck



CS Fe203 03
0.38
0.21


1.06

241.0
0.47
Good fibre
Not Stuck



CS05
0.33
0.19
0.10

0.16

262.0
0.45
Lots of flake
Not Stuck



CS06/E
0.33
0.28


0.15

222.0
0.34
Lots of flake
Not Stuck



CS06/E cons
0.33
0.28


0.15

222.0
0.34
Lots of flake
Not Stuck



CS Al 02
0.33
0.19


0.14


0.59
Good fibre
Not Stuck



CS07/E
0.33
0.11


0.15

177.9
0.29
O.K fibre
Not stuck



CS14/B
0.30
0.12


0.17

137.3
0.55
Shotty
Not Stuck



CS08/E
0.27


0.16
0.18

160.0
0.32
Coarse
Not Stuck



CS06/B
0.26
0.15


0.12

172.0
0.55
Lots of flake
Not Stuck




















TABLE 2









Shrinkage %/24 hrs
Composition (wt %)



















Comp.
1300° c.
1350° c.
1400° c.
1450° c.
1500° c.
1550° c.
CaO
SiO2
P2O3
Al2O3
B2O3
ZrO2





CAS01

17.62
18.45



24.50
71.70

2.78

0.45


CAS02

10.19
24.18



22.60
73.50

2.52

0.91


CAS03

5.42
14.63
14.56


20.40
75.70

2.32

1.05


CS03/C

6.02
melted
melted


31.50
65.60

0.83

0.14


CZrS02

15.01
31.08



27.40
65.80

0.70

3.85


CZrs03

7.39
30.64



25.60
68.00

0.67

3.96


CS11

4.96
19.95
34.81


29.00
68.90

0.75

0.13


CS11 cons

4.96
11.42
22.67


29.00
68.90

0.75

0.13


CZrS07

−0.29




17.90
74.70

0.62

4.94


CZrS06

melted
7.97



19.00
74.90

0.71

4.45


CZrS04

2.56




24.50
70.60

0.72

3.29


CS13 cons

1.46
3.56
12.88
16.60
28.58
24.30
73.30

0.57

0.73


CAS07

4.59
10.22



24.80
73.10

1.10

0.43


CSMg04

1.76
2.94



16.70
79.40

0.38

0.43


CS08
1.24
1.30
1.74
3.37


19.80
78.50

0.45

0.34


CS05/B
0.86
1.53
5.56



26.00
72.00

0.62

0.33


CS05/B cons

1.53
4.52
13.46


26.00
72.00

0.62

0.33


CS05/E

2.04
7.28
33.19
44.49

26.00
72.00

0.62

0.33


CS05/E cons

2.04
8.19
20.34
25.44
28.00
26.00
72.00

0.62

0.33


CS06
1.36
1.42
2.36
5.87
melted

23.40
73.30

1.77

0.27


CSMg05

1.67
1.26



16.40
79.80

0.35

0.14


CS07/B
0.86
1.50
2.17
10.00
15.00

22.20
76.60

0.52

0.12


CS07/B cons

1.50
1.31
2.93
5.19
5.81
22.20
76.60

0.52

0.12


CS07
1.08
1.06
1.15
3.34


22.30
76.90

0.35

0.10


















Total



Total



Composition (wt %)
Solubility
SSA
Fibre
JM 28
SiO2 +




















Comp.
MgO
Na2O
K2O
TiO2
Fe2O3
ZnO
ppm
m2/g
Quality
sticking
ZrO2







CAS01
0.28
0.12


0.12

30.3

Coarse
Stuck
72.15



CAS02
0.25
0.11


0.15

20.1

Coarse
Stuck
74.41



CAS03
0.23
0.11


0.12

47.4
0.20
Coarse
Stuck
76.75



CS03/C
0.47
0.36
0.14

0.23

222.0
0.31
Coarse
Stuck
65.74



CZrS02
0.40
0.37
0.12

0.19

107.2
0.39
Good fibre
Stuck
69.65



CZrs03
0.37
0.25
0.11

0.21

64.2
0.21
Good fibre
Stuck
71.96



CS11
0.47
0.30
0.13

0.19

200.5
0.50
Coarse
Stuck
69.03



CS11 cons
0.47
0.30
0.13

0.19

200.5
0.50
Coarse
Stuck
69.03



CZrS07
0.24
0.48


0.17

24.3
0.22
Very shotty
Not Stuck
79.64



CZrS06
0.28
0.42


0.13

42.5
0.25
Coarse
Not Stuck
79.35



CZrS04
0.36
0.35
0.11

0.17

69.4
0.21
Good fibre
Not Stuck
73.89



CS13 cons
0.31
0.26


0.20

156.0
0.56
Shotty
Not Stuck
74.03



CAS07
0.28
0.14


0.14

127.8
0.34
Coarse
Not Stuck
73.53



CSMg04
2.35



0.18

243.0
0.09
Coarse shotty
Not Stuck
79.83



CS08
0.25
0.16


0.14

201.5
0.20
Lots of flake
Not Stuck
78.84



CS05/B
0.31
0.22


0.15

182.0
0.34
Lots of flake
Not Stuck
72.33



CS05/B cons
0.31
0.22


0.15

182.0
0.34
Lots of flake
Not Stuck
72.33



CS05/E
0.31
0.22


0.15

276.0
0.48
Lots of flake
Not Stuck
72.33



CS05/E cons
0.31
0.22


0.15

276.0
0.48
Lots of flake
Not Stuck
72.33



CS06
0.32
0.14


0.14

244.6
0.32
Lots of flake
Not Stuck
73.57



CSMg05
2.46



0.13

237.2
0.11
Good fibre some shot
Not Stuck
79.94



CS07/B
0.26
0.11


0.12

104.0
0.23
Lots of flake
Not Stuck
76.72



CS07/B cons
0.26
0.11


0.12

104.0
0.23
Lots of flake
Not Stuck
76.72



CS07
0.24
0.17


0.11

203.5
0.25
Lots of flake
Not Stuck
77.00




















TABLE 3









Shrinkage %/24 hrs
Composition (wt %)



















Comp.
1300° c.
1350° c.
1400° c.
1450° c.
1500° c.
1550° c.
CaO
SiO2
P2O5
Al2O3
B2O3
ZrO2





CBS04

3.54
6.97
7.16


18.00
77.90

0.43
2.03
0.70


CBS03

3.47
10.32
16.43


20.40
75.20

0.48
2.12
0.84


CPS02/B


4.02



21.40
75.00
1.54
0.48


CPS02

0.66
0.91
0.70


22.40
74.60
1.61
0.29
0.26
0.90


CPS02 cons

0.66
0.25
−0.21


22.40
74.60
1.61
0.29
0.26
0.90


CPS21

3.04




23.00
74.10
0.42
0.61


CBS05

4.14
9.98
14.71


21.20
73.90

0.54
3.11


CPS20

2.48
9.10



23.80
73.80
0.38
0.66

0.29


CPS20 cons

2.48
6.21
11.94
17.39
20.69
23.80
73.80
0.38
0.66

0.29


CPS18/B

1.93
6.72
16.07


23.90
73.20
0.87
0.59


CPS17/B

2.39
6.36



24.70
72.80
0.88
0.65


CPS01/B

1.73
8.96
12.58


23.50
72.70
1.58
0.58


CPS01/C

2.05
11.86
5.87
6.10

23.80
72.60
1.58
0.46


CBS02

4.93
18.32
23.28


22.90
72.60

0.70
2.16
0.30


CBS07

−0.29
6.10
14.69


24.30
72.20

0.38
1.38
0.84


CPS01

2.29
1.25
0.15


23.90
71.50
1.52
0.48
0.90
0.95


CPS01 cons

2.29
1.25
0.15


23.90
71.50
1.52
0.48
0.90
0.95


CPS17

2.86




25.20
71.50
0.90
0.66


CPS19

2.87
19.23
26.90


25.50
71.50
0.48
0.64

0.15


CBS01

3.79
21.92



25.20
70.90

0.62
2.13
0.84


CPS15/B

2.24
12.71
27.90
35.55

27.00
70.50
0.83
0.64


CPS16

3.96
20.90
27.90


26.00
70.20
0.89
0.69

0.23


CPS15

2.76
13.37
28.94


26.70
70.00
0.93
0.69


CPS15 cons

2.76

14.74
17.67

26.70
70.00
0.93
0.69


CPS14/B

4.08
28.80



29.70
67.70
0.90
0.69


CS03
1.36
1.55
5.03
melted


30.20
67.60
0.15
0.87


CS03/E

3.81
18.22
melted
melted

30.20
67.60
0.15
0.87


CS03/E cons

3.81
13.67
28.02


30.20
67.60
0.15
0.87


CPS13

6.92
4.00
38.52


30.20
65.70
0.93
0.70


CPS14

1.90
13.10
melted


30.80
64.80
0.99
0.80


CPS14 cons

1.90
5.30
11.68
15.88

30.80
64.80
0.99
0.80


CPS12

8.72
5.93
melted


32.10
63.80
0.89
0.75


CPS11

15.72
10.06
melted


34.40
62.00
0.99
0.81

0.10






















Total SiO2 +




Total



B2O3 +



Composition (wt %)
Solubility
SSA
Fibre
JM 28
ZrO2 +




















Comp.
MgO
Na2O
K2O
TiO2
Fe2O3
ZnO
ppm
m2/g
Quality
sticking
5.P2O5







CBS04
0.31
0.17


0.24

64.0
0.16
Coarse
Not stuck
80.63



CBS03
0.33
0.18


0.18

73.0

Coarse
Not stuck
78.16



CPS02/B
0.32
0.13


0.16

336.0
0.27
Coarse
Not Stuck
82.70



CPS02
0.27
0.21


0.11

349.6
0.10
O.K fibre
Not Stuck
83.81



CPS02 cons
0.27
0.21


0.11

336.8
0.10
Coarse
Not Stuck
83.81



CPS21
0.45
0.38
0.10

0.20

188.0
0.41
O.K fibre
Not Stuck
76.20



CBS05
0.32
0.16


0.17

117.0
0.35
Coarse
Not Stuck
77.01



CPS20
0.35
0.18
0.11

0.16

229.0
0.33
Good fibre
Not Stuck
75.99



CPS20 cons
0.35
0.18
0.11

0.16

229.0
0.33
Good fibre
Not Stuck
75.99



CPS18/B
0.34
0.19


0.15

161.0
0.42
Shotty
Not Stuck
77.55



CPS17/B
0.36
0.17


0.16

152.0
0.58
O.K fibre
Not Stuck
77.20



CPS01/B
0.33
0.20


0.15

275.0
0.34
Good fibre
Not Stuck
80.60



CPS01/C
0.34
0.32


0.32

338.8
0.50
Coarse
Not Stuck
80.50



CBS02
0.33
0.24


0.15

85.0

Good fibre
Not stuck
75.06



CBS07
0.27
0.18


0.13

90.0
0.32
Shotty
Not Stuck
74.42



CPS01
0.29
0.48


0.10

286.3
0.13
O.K fibre
Not Stuck
80.95



CPSO1 cons
0.29
0.48


0.10

338.8
0.13
Coarse
Not Stuck
80.95



CPS17
0.37
0.37
0.11

0.28

241.0
0.49
Shotty
Not Stuck
76.00



CPS19
0.39
0.44
0.11

0.18

172.0
0.40
Good fibre
Not Stuck
74.05



CBS01
0.41
0.12


0.20

101.2
0.45
Good fibre
Not Stuck
73.87



CPS15/B
0.39
0.15


0.17

177.0
0.38
Coarse
Stuck
74.65



CPS16
0.38
0.53
0.11

0.18

181.0
0.54
Coarse
Not Stuck
74.88



CPS15
0.43
0.38
0.12

0.20

166.6
0.61
Coarse
Not Stuck
74.65



CPS15 cons
0.43
0.38
0.12

0.20

166.6
0.61
Coarse
Not Stuck
74.65



CPS14/B
0.46
0.19
0.10

0.22

153.9
0.32
O.K fibre
Not Stuck
72.20



CS03
0.42
0.21
0.11

0.18

240.5
0.61
Coarse
Stuck
68.35



CS03/E
0.42
0.21
0.11

0.18

260.0
0.47
Coarse
Stuck
68.35



CS03/E cons
0.42
0.21
0.11

0.18

260.0
0.47
Coarse
Stuck
68.35



CPS13
0.47
0.54
0.13

0.20

163.8
0.44
O.K. fibre
Stuck
70.35



CPS14
0.48
0.30
0.13

0.21

153.9
0.47
O.K fibre
Stuck
69.75



CPS14 cons
0.48
0.30
0.13

0.21

153.9
0.47
O.K fibre
Stuck
69.75



CPS12
0.49
0.31
0.14

0.20

165.6
0.55
Lots of
Stuck
68.25












flake



CPS11
0.55
0.31
0.13

0.21

170.5
0.53
Good fibre
Stuck
67.05




















TABLE 4









Shrinkage %/24 hrs
Composition (wt %)



















Comp.
1300° c.
1350° c.
1400° c.
1450° c.
1500° c.
1550° c.
CaO
SiO2
P2O5
Al2O
B2O3
ZrO2





50% YIELD

0.64
1.30
6.78
28.55
30.83
25.50
72.70

0.59


SPUN

0.38
0.77
5.48
30.54
40.30
25.40
73.10

0.67


BLOWN

0.80
1.30
7.89
29.43
39.64
25.30
73.10

0.54


Blanket
0.61
0.90




23.00
74.60

0.56


BAG 24

0.85
1.43
4.69
18.36
25.69
23.18
75.18

0.66


BAG 7

0.57
0.84
2.22
22.32
26.70
24.26
73.95

0.63


BAG 41

0.83
1.02
1.51
12.12
17.85
21.62
76.65

0.79


BAG 46

1.56
0.96
1.36
7.69
12.84
18.70
79.80

0.81


BAG 62

0.65
3.24
8.33
13.25
22.84
19.74
76.25

0.47

0.82


No. 3

3.36
8.02



19.94
75.35

0.37

1.11


No. 4

2.54
8.12



20.81
75.45

0.39

1.05


No. 5

1.96
6.55



20.61
75.28

0.36

0.99


Blanket 1st
0.54





23.80
74.20

0.62


Blanket Last
1.13
1.37
6.00
16.21
28.76
melted
25.01
72.89

0.57


Blanket 1st

1.28
1.79
2.56
27.17
25.11
23.80
74.20

0.62


Blanket Last

1.06
1.35
1.71
21.38
31.51
25.01
72.89

0.57


Bulk Hi Speed

1.52
1.81
13.71
24.15
24.56
24.90
72.20

0.72

















Total






Composition (wt %)
Solubility
SSA
Fibre
JM 28



















Comp.
MgO
Na2
K2O
TiO2
Fe2O3
ZnO
ppm
m2/g
Quality
sticking







50% YIELD
0.50


0.26
0.19

232.0
0.22
Very good
Not Stuck



SPUN
0.54



0.18

254.0
0.23
Very good
Not Stuck



BLOWN
0.55



0.22

196.8
0.47
Very good
Not Stuck



Blanket
0.43
0.22
0.12

0.17

240.7
0.16
Very good
Not Stuck



BAG 24
0.42



0.17

300.0
0.23
Very good
Not Stuck



BAG 7
0.45



0.19

117.0
0.16
Very good
Not Stuck



BAG 41
0.38



0.17

127.0
0.17
Very good
Not Stuck



BAG 46
0.43



0.14

62.0
0.17
Very good
Not Stuck



BAG 62
2.27



0.15

95.0
0.16
Very good
Not Stuck



No. 3
2.99



0.16

202.8
1.15
Very good
Not Stuck



No. 4
2.87



0.16

210.2
0.61
Very good
Not Stuck



No. 5
2.70



0.16

229.4
0.88
Very good
Not Stuck



Blanket 1st
0.77





205.2
0.41
Very good
Not Stuck



Blanket Last
0.92





264.4
0.15
Very good
Not Stuck



Blanket 1st
0.77





205.2
0.41
Very good
Not Stuck



Blanket Last
0.92





264.4
0.15
Very good
Not Stuck



Bulk Hi Speed
0.82





267.5
0.15
Very good
Not Stuck

## Claims

1. A silicate fibre comprising:
65%<SiO2<86%
MgO<10%
14%<CaO<28%
Al2O3<2%
ZrO2<3%
B2O3<5%
P2O5<5%
72%<SiO2+ZrO2+B2O3+5*P2O5 
95%<SiO2+CaO+MgO+Al2O3+ZrO2+B2O3+P2O5 
0.1%<R2O3<4%
where R is selected from the group Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y or mixtures thereof.

2. A silicate fibre as claimed in claim 1, in which R is La or Y or mixtures thereof.

3. A silicate fibre as claimed in claim 2, in which R is La.

4. A silicate fibre as claimed in claim 1, in which the amount of R2O3 is greater than 0.25%, by weight.

5. A silicate fiber as claimed in claim 4, in which the amount of R22 O3 is greater than 0.5% by weight.

6. A silicate fiber as claimed in claim 5, in which the amount of R2O3 is greater than 1.0% by weight.

7. A silicate fibre as claimed in claim 1, in which the amount of R2O3 is <2.5% by weight.

8. A silicate fiber as claimed in claim 7, in which the amount of R2O3is greater than 1.5% by weight.

9. A silicate fibre as claimed in claim 1, having the composition in wt %:
72%<SiO2<80%
18%<CaO<26%
0%<MgO<3%
0%<Al2O3<1%
0%<ZrO2<1.5%
1%<R2O3<2.5%.

10. A silicate fibre as claimed in claim 9, in which R comprises La.

11. A silicate fibre as claimed in claim 10, having the composition in wt %:
SiO2:73±0.5%
CaO:24±0.5%
La2O3:1.3–1.5%
Remaining components:<2%.

12. A silicate fiber as claimed in claim 11 in which remaining components are <1.5% by weight.

13. Thermal insulation comprising silicate fibres as claimed in claim 1.

14. A silicate fibre as claimed in claim 1, in which the glass is soluble in physiological fluids.

15. A silicate fibre as claimed in claim 1, in which said fibre is usable as refractory insulation requiring continuous resistance to a temperature of 1260° C.

16. A silicate fibre as claimed in claim 1, in which said fibre does not react with aluminosilicate brick at 1260° C.

17. A method of improving the fiberisation of alkaline earth silicate fibres having a composition in wt %
65%<SiO2, <86%
MgO<10%
14%<CaO<28%
Al2O3<2%
ZrO2,<3%
B2O3<5%
P2O5<5%
72%<SiO2+ZrO2+B2O3+5*P2O5 
95%<SiO2+CaO+MgO+Al2O3+ZrO2+B2O3+P2O5by inclusion in the components of the fibre of R2O3 in amounts ranging from 1% to 4% by weight, where R is selected from the group Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y or mixtures thereof.

18. A method as claimed in claim 17, in which R is La or Y or mixtures thereof.

19. A method as claimed in claim 18, in which R is La.

20. A blanket composed of silicate fibres having a composition comprising:
65%<SiO2<86%
MgO<10%
14%<CaO<28%
Al2O3<2%
ZrO2<3%
B2O3<5%
P2O5<5%
72%<SiO2+ZrO2+B2O3+5P2O5 
95%<SiO2+CaO+MgO+Al2O3+ZrO2+B2O3+P2O5 
0.1%<R2O3<4%
where R is selected from the group Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y or mixtures thereof.

21. An article of insulation composed of silicate fibers having a composition comprising:
65%<SiO2<86%
MgO<10%
14%<CaO<28%
Al2O3<2%
ZrO2<3%
B2O3<5%
P2O5<5%
72%<SiO2+ZrO2+B2O3+5*P2O5 
95%<SiO2+CaO+MgO+Al2O3+ZrO2+B2O3+P2O5 
0.1%<R2O3<4%
where R is selected from the group Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y or mixtures thereof.