AU2021106772A4

AU2021106772A4 - Thermal insulation

Info

Publication number: AU2021106772A4
Application number: AU2021106772A
Authority: AU
Inventors: Farid Modarresifar
Original assignee: Thermal Ceramics UK Ltd
Current assignee: Thermal Ceramics UK Ltd
Priority date: 2020-10-23
Filing date: 2021-08-24
Publication date: 2021-11-18
Anticipated expiration: 2029-08-24

Abstract

The present invention relates to an insulation or sealant system comprising: a. a refractory component comprising a contact surface; and b. an insulating or sealant material comprising inorganic fibres having a composition comprising: 65.7 to 70.8 wt% SiO 2 ; 27.0 to 34.2 wt% CaO; 0.10 to 2.0 wt% MgO; and optional other components providing the balance up to 100 wt%. The sum of SiO2 and CaO is greater than or equal to 97.8 wt%, wherein the other components, when present, comprises no more than 0.80 wt% A1 20 3; wherein the insulating or sealant material is disposed against the contact surface, and wherein said refractory component comprises at least 20 wt% alumina.

Description

THERMAL INSULATION FIELD OF THE INVENTION

This disclosure relates to thermal insulation comprising bio-soluble inorganic fibre compositions and more particularly insulation materials comprising said fibre. The disclosure also relates to the use of said fibre at temperatures up to and in excess of 1200°C.

BACKGROUND

The insulation material industry has determined that it is desirable to utilize fibres in thermal, electrical and acoustical insulating applications, which do not persist in physiological fluids. That is, fibre compositions which are considered to have low biopersistence (i.e. bio-soluble) in physiological fluids.

While candidate silicate materials have been proposed, the use temperature limit of these materials have not been high enough to accommodate many of the applications to which high temperature resistant fibres are applied. For example, such bio-soluble fibres exhibit high shrinkage at use temperatures and/or reduced mechanical strength when exposed to use temperatures ranging from 1000°C. to 1500°C. as compared to the performance of refractory ceramic fibres.

The high temperature resistant fibres should exhibit minimal shrinkage at expected exposure temperatures, and after prolonged or continuous exposure to the expected use temperatures, in order to provide effective thermal protection to the article being insulated. In addition to bio solublity and high temperature resistance the fibres should possess a low diameter and low shot content for the resultant insulation materials to have low density and thermal conductivity. The multitude of requirements do not end there, with fibres also needing to be non-reactive to other materials in the insulation system they may form part of.

In 1987 Manville Corporation developed bio-soluble high temperature resistant fibres based on a calcium magnesium silicate chemistry (US5,714,421). Such material not only had a higher temperature capability than traditional glass wools, but also had a higher solubility in body fluids than the aluminosilicate fibres mostly used for high temperature insulation. US5,714,421 taught the necessity to combine silica, calcia and magnesia with a variety of other metal oxide additives to obtain the desired combination of fibre properties and form.

While there are many commercial examples of the biosoluble high temperature resistant fibres

which have stemmed from magnesia, calcia, silica systems, there is still a need for improved bio

soluble high temperature resistant fibres and insulation material thereof.

International Application WO 87/05007 discloses inorganic fibres consisting essentiallyof SiO 2 , CaO

with specified ranges of MgO and A1 2 03 , which were obtained from metal oxides rather than raw by

product materials with variable composition. It was observed that lower A1 2 0 3 levels resulted in a

surprisingly high bio-solubility level.

International Application WO 94/15883 discloses CaO/MgO/SiO 2 fibres with additional constituents

A12 03, Zr 2 , and Ti 2 , for which saline solubility and refractoriness were investigated. The document

states that saline solubility appeared to increase with increasing amounts of MgO, whereas ZrO 2 and

A12 03 were detrimental to solubility. The presence of TiO 2 (0.71-0.74 mol %) and A1 20 3 (0.51-0.55 mol

%) led to the fibres failing the shrinkage criterion of 3.5% or less at 1260 C. The document further

states that fibres that are too high in SiO 2 are difficult or impossible to form, and cites fibres having

70.04, 73.09, 73.28 and 78.07 wt% SiO 2 as examples of compositions which could not be fiberized.

US6,953,757 discloses an inorganic high silica fibre composition comprising predominately silica,

calcia, magnesia and zirconia and optionally viscosity modifiers, such as alumina and boria, to enable

product fiberisation.

JP2003003335 disclosures the inorganic fibres comprising silica and calcia to avoid precipitation of

cristobalite at the fibres are heated to 1000C or greater. To avoid precipitation of cristobalite, the levels of Na 20, K 20, Ti 2, Fe 2 O 3 and MgO are reduced or not added, with high purity calcia and silica

used as raw materials.

US2004/254056 claimed CaO/SiO 2 fibres comprising greater than or equal to 72wt% SiO 2 , or for

which the sum SiO 2 +ZrO 2+B 2 03 +5*P2 05 was greater than 72wt%. Such fibres had a low propensity for

reaction with aluminosilicate bricks whereas fibres with lower SiO 2 +ZrO 2 +B 20 3 +5*P 20 5 content

tended to react adversely with aluminosilicate bricks.

Despite advances in the field, there is still a need for a simplified fibre composition which is not

reliant upon a range of additives to obtain the required combination of fibre properties and form.

There is also a need for a simplified fibre composition which is not reliant on high impurity raw materials in their production, with the purification processes often used to produce such high purity raw materials increasing the carbon footprint of the resultant inorganic fibres.

SUMMARY OF THE DISCLOSURE

The applicant has found that, contrary to received wisdom in the field of refractory alkaline earth

silicate fibres, that refractory fibres with high utility are able to be produced without the addition of

significant amounts of additives, such as viscosity modifiers, solubility or refractory enhancers, to a

SiO2 -CaO system, within a specified compositional range.

According to a first aspect of the prevent disclosure there is provided inorganic fibres having a

composition comprising:

61.0 to 70.8 wt% SiO 2 ;

27.0 to 38.9 wt% CaO;

0.10 to 2.0 wt% MgO; and

optional other components providing the balance up to 100 wt%,

wherein the sum of SiO2 and CaO is greater than or equal to 97.8 wt% and wherein the other

components, when present, comprise no more than 0.80 wt% A1 20 3 .

The following alternative expression may also be used to define the first aspect of the present

disclosure, with the inorganic fibres having a composition comprising:

61.0 to 70.8 wt% SiO 2 ;

SiO2 + CaO is greater than or equal to 97.8 wt%. 0.10 to 2.0 wt% MgO; and

optional other components providing the balance up to 100 wt%, wherein the other

components, when present, comprise no more than 0.80 wt% A1 20 3 .

It has been found that there is a narrow compositional window in which a small amount of MgO

unexpectedly inhibits the formation of large surface crystallite grains at high temperatures, whilst

not significantly affecting the high temperature performance of the fibres. Large surface crystallite

grains on fibres may result in the creation of stress points which adversely affects the mechanical

properties of the fibres at high temperatures. Therefore, it is desirable to minimise the size of the

surface crystallite phases formed at high temperatures when the fibres are in use.

The sum of SiO2 and CaO may be greater than or equal to 97.9 wt% or greater than or equal to 98.0 wt% or greater than or equal to 98.1 wt% or greater than or equal to 98.2 wt% or greater than or equal to 98.3 wt% or greater than or equal to 98.4 wt% or greater than or equal to 98.5 wt% or greater than or equal to 98.6 wt% or greater than or equal to 98.7 wt% or greater than or equal to

98.8 wt% or greater than or equal to 98.9 wt% or greater than or equal to 99.0 wt% or greater than

or equal to 99.1 wt% or greater than or equal to 99.2 wt% or greater than or equal to 99.3 wt% or

greater than or equal to 99.4 wt% or greater than or equal to 99.5 wt%. The higher proportion of

SiO2 and CaO (and the lower proportion of other components) is thought to reduce the propensity of surface crystallite formation at high temperatures. The upper limit of the purity is likely to be

constrained by the cost and availability of raw materials, particularly raw materials with a relatively

low carbon footprint (e.g. materials that have not been chemically purified or otherwise processed).

The upper limit of the sum of SiO 2 and CaO may also be limited by the ability to manufacture

inorganic fibres, particularly with fine fibre diameter (e.g. <6 pm and/or less than 52 wt% shot (<45

p.m)).

In some embodiments, the amount of MgO is configured to inhibit the formation of surface

crystallite grains upon heat treatment at 1100C for 24 hours, wherein said surface crystallite grains

comprise an average crystallite size in the range of from 0.0 to 0.90 pm.

In addition to the presence of a small amount of MgO, the target compositional range may also be

restricted in the amount of other components, such as additives or incidental impurities. In

particular, limitations to the amount of alumina, titania and alkaline metal oxides are desirable to

avoid the promotion of large crystallite grains.

In some embodiments, the amount of other components is configured to inhibit the formation of

surface crystallite grains upon heat treatment at 1100C for 24 hours, wherein said surface crystallite

grains comprise an average crystallite size in a range of from, 0.0 to 0.90 m.

The inorganic fibres which after heat treatment at 1100C for 24 hours may comprise surface crystallite grains with an average crystallite size of 0.90 m or less; or 0.80 pm or less; or 0.70 am or

less; or 0.60 pm or less; or 0.50 pm or less; or less than 0.40 pm. Preferably, there are no surface

crystallite grains (i.e. crystallite size = 0.0 pm) or no detectable surface crystallite grains.

The amount of MgO and/or other components may also be configured such that a vacuum cast

preform of the fibres has a shrinkage of 3.5% or less when exposed to 1200°C or 1300°C for 24 hrs.

In some embodiments, the fibre composition is configured to comprise both crystallite grain

inhibiting properties at high temperatures as well as possessing the low shrinkage properties.

The amount of other components is no more than 2.1 wt% and may be no more than 2.0 wt% or no

more than 1.9 wt% or no more than 1.8 wt% or no more than 1.7 wt% or no more than 1.6 wt% or

no more than 1.5 wt% or no more than 1.4 wt% or no more than 1.3 wt% or no more than 1.2 wt%

or no more than 1.1 wt% or no more than 1.0 wt% or no more than 0.9 wt% or no more than 0.8

wt% or no more than 0.7 wt% or no more than 0.6 wt%. Higher levels of other components may

adversely affect the high temperature performance of the fibres. By being able to utilise raw

materials with higher impurity levels, but within the prescribed ranges, greater utilisation of natural

resources is obtainable without the need for further processing, including chemical purification. The

other components typically comprise at least 0.2 wt% or at least 0.3 wt% or at least 0.4 wt% or at

least 0.5 wt% of the inorganic fibre composition. While the use of more pure raw materials is

possible, this is likely to be accompanied with an increased carbon footprint and cost due to the

need for additional purification processes. Further, these other components, which may include

incidental impurities, are thought to assist with fiberisation of the composition.

In some embodiments, a small amount of additives may be included to fine-tune the properties of

the fibres. Additive addition may be greater than 0.0 wt% or greater than 0.10 wt% or greater than 0.20 wt% or greater than 0.30 wt%. Additive addition may be less than 2.0 wt% or less than 1.7 wt%

or less than 1.5 wt% or less than 1.4 wt% or less than 1.3 wt% or less than 1.1 wt% or less than 1.2

wt% or less than 1.0 wt% or less than 0.9 wt% or less than 0.8 wt% or less than 0.7 wt% or less than

0.6 wt% or less than 0.5 wt% or less than 0.4 wt% or less than 0.3 wt% or less than 0.2 wt% of the

inorganic fibre composition.

The additives may be one or more metals in an oxide or non-oxide form, including but not limited to

bromides, chlorides, fluorides, phosphates, nitrates, nitrites, oxides, carbonates and/or sulphates.

Metals may for example include alkali metals, alkaline earth metals transition metals, post-transition

metals and lanthanides. For the purposes of the present disclosure metal may also include

metalloids.

In some embodiments, additives are added for the purpose of one or more of:

• assisting in fiberisation (melt viscosity modifiers);

• enhancing high temperature performance;

* facilitating the formation of finer fibre diameters whilst maintaining the required bio

solubility and high temperature usage characteristics.

The additives may include oxides or non-oxides (e.g. fluorides) of one or more of the lanthanides

series of elements (e.g. La, Ce), Li, Na, K, Sr, Ba, Cr, Fe, Zn, Y, Zr, Hf; Ca, B, P or combinations thereof.

In another embodiment the other components comprise one or more oxides or non-oxides of

lanthanides, Sr, Ba, Cr, Zr or combinations thereof. The fibre composition may include 0.05 to 1.0

wt% additives or 0.10 to 0.80 wt% or 0.15 wt to 0.60 wt% additives. The additives are preferably

sourced from a naturally occurring mineral deposits. The addition of viscosity modifiers is

particularly advantageous when added to fibre compositions with a SiO 2 content of greater than 66.0

wt% or 67.0 wt% or 68.0 wt% or 69.0 wt%.

It has been found that within this compositional window, bio-soluble high temperature resistant

fibres are melt formable. Additionally, when the fibre composition of 65.7 wt% or greater SiO 2 the

fibre has been shown to be also non-reactive in the presence of alumina based materials at high

temperatures. Other networker formers (e.g. ZrO2) have been shown to have a substitutability with

SiO2 and, as such, fibre compositions of 65.7 wt% or greater of the sumof SiO 2+ ZrO 2 would also be

expected to be non-reactive in the presence of alumina based materials at high temperatures.

In some embodiments, the inorganic fibres are non-reactive when in contact with an alumina

composition (such as mullite) at 12000 C for 24 hours. Alumina compositions preferably include

compositions with at least 20 wt% A1 2 O3 or at least 30 wt% A1 2O 3 or at least 40 wt% A1 2O 3 or at least

wt% A12 O3 . However, the benefits of this higher silica content may still exist at lower alumina

content levels, depending upon the atmosphere, temperature and duration of exposure.

In some embodiments, the other components comprise or consist of incidental impurities in the raw

materials used to make the inorganic fibres, including coal ash, when coal is used as an energy

source to melt in the inorganic fibre precursor material, such as silica sand and lime.

In some embodiments, the main impurity in lime comprises magnesia. Other impurities may include

alumina, iron oxide and alkali metal oxides, such as K 20 and Na 20.

In some embodiments, the sum of SiO2 and CaO and MgO is greater or equal to 98.5 wt% or greater

or equal to 98.8 wt% or greater or equal to 99.0 wt% or greater or equal to 99.1 wt% or greater or

equal to 99.2 wt% or greater or equal to 99.3 wt% or greater or equal to 99.4 wt% or greater or

equal to 99.5 wt% of the fibre composition.

In some embodiments, the inorganic fibre composition comprises less than 1.7 wt% MgO or less than

1.5 wt% MgO or less than 1.2 wt% or less than 1.0 wt% MgO or less than 0.90 wt% or less than 0.88

wt% or less than 0.85 wt% or less than 0.82 wt% or less than 0.80 wt% or less than 0.75 wt% or less

than 0.70 wt% or less than 0.60 wt% MgO or less than 0.50 wt% or less than 0.45 wt% MgO derived

from the incidental impurities. Higher contents of MgO has been found to detrimentally affect the

thermal stability of the fibres at 12000 C or 13000 C. The composition preferably comprises at least

0.11 wt% or at least 0.12 wt% or at least 0.14 wt% or at least 0.16 wt% or at least 0.18 wt% or at

least 0.20 wt% MgO.

In some embodiment, the sum of SiO 2 + CaO + MgO + Al2 O3 is greater than or equal to 99.3 wt% or

greater than or equal to 99.4 wt% or greater than or equal to 99.5 wt% or greater than or equal to

99.6 wt% or greater than or equal to 99.7 wt% of the inorganic fibre composition.

Preferably, inorganic fibre composition comprises less than 0.80 wt% A1 2 03 or less than 0.79 wt%

A12 03 or less than 0.78 wt% A12 03 or less than 0.77 wt% A12 03 or less than 0.76 wt% A1 2 03 or less than

0.75 wt% A12 03 or less than 0.74 wt% A1 2 03 or less than 0.73 wt% A1 20 3 or less than 0.72 wt% A1 20 3 or

less than 0.71 wt% A1 2 03 or less than 0.70 wt% A1 2 03 or less than 0.69 wt% A1 2 0 3 or less than 0.68

wt% A12 03 or less than 0.67 wt% A12 03 or less than 0.66 wt% A1 2 03 or less than 0.65 wt% A1 20 3 or less

than 0.64 wt% A12 03 or less than 0.63 wt% A1 2 03 or less than 0.62 wt% A1 2 03 or less than 0.61 wt%

A12 03 or less than 0.60 wt% A12 03 or less than 0.55 wt% A12 03 or less than 0.50 wt% A1 2 03 or less than

0.45 wt% A12 03 or less than 0.40 wt% A1 2 03 or less than 0.35 wt% A1 20 3 or less than 0.30 wt% A1 20 3 or

less than 0.25 wt% A1 2 0 3, preferably derived from the incidental impurities. The amount of A1 20 3 is

typically 0.0 wt% or greater. Within the current SiO 2-CaO composition, higher levels of A1 20 3 have been found to adversely affect the bio-solubility and thermal stability of the inorganic fibres, in

addition to promoting crystallite growth at elevated temperatures.

In another embodiment, the sum of MgO and A1 2 03 in the inorganic fibres is no more than 2.0 wt%

or no more than 1.80 wt% or no more than 1.50 wt% or no more than 1.20 wt% or no more than 1.10 wt% or no more than 1.00 wt% or no more than 0.90 wt% or no more than 0.80 wt% or no more

than 0.70 wt% or no more than 0.60 wt%.

In other embodiments, a vacuum cast preform of the inorganic fibre has a composition configured to

obtain a shrinkage of 8.0% or less, 7.0% or less, 6.0% or less, 5.0% or less, 4.5% or less, 4.0% or less, 3.0% or less, 2.5% or less, or 2.0% or less when exposed to 1200°C for 24 hours. In another

embodiment, a vacuum cast preform of the inorganic fibre has a composition configured to obtain a

shrinkage of 8.0% or less, 7.0% or less, 6.0% or less, 5.0% or less, 4.5% or less, 4.0% or less, 3.0% or

less, 2.5% or less, or 2.0% less when exposed to 1300°C for 24 hours.

The melting temperature of the inorganic fibres is preferably at least 1350°C or at least 1380°C or at least1400°Cor at least1420°C.

To aid fiberisation, particularly in the absence of additives, the SiO 2 content of the inorganic fibre

composition is preferably less than 70.7 wt% or less than 70.6 wt% or less than 70.5 wt% or less than

70.4 wt% or less than 70.2 wt% or less than 70.0 wt% or less than 69.8 wt% or less than 69.6 wt%.

less than 69.4 wt% or less than 69.2 wt% or less than 69.0 wt% or less than 68.8 wt% or less than

68.5 wt% or less than 68.3 wt% or less than 68.1 wt% or less than 68.0 wt%. To aid resiliency at high

temperature and minimise reactivity with alumina containing substrates, the SiO 2 content of the

inorganic fibre composition is preferably at least 61.1 wt% or at least 61.2 wt% or at least 62.3 wt%

or at least 62.4 wt% or at least 62.5 wt% or at least 62.6 wt% at least 62.7 wt% or at least 62.8 wt%

or at least 62.9 wt% or at least 63.0 wt% or at least 63.5 wt% or at least 64.0 wt% or at least 64.5

wt% or at least 65.0 wt% or at least 65.7 wt% or at least 65.8 wt% or least 66.0 wt% or at least 66.2

wt% or at least 66.4 wt% or at least 66.6 wt% or at least 66.8 wt% or at least 67.0 wt% or at least

67.2 wt% or at least 67.4 wt%.

The CaO content of the inorganic fibre composition preferably varies accordingly, with the lower

limit of CaO preferably at least 27.0 wt% or at least 27.2 wt% at least 27.5 wt% or at least 28.0 wt%

or at least 28.5 wt% or at least 29.0 wt% or at least 29.5 wt% or at least 30.0 wt%. The upper limit of

the CaO content of the inorganic fibre composition is preferably no more than 38.5 wt% or no more

than 38.0 wt% or no more than 37.5 wt% or no more than 37.0 wt% or no more than 36.5 wt% or no

more than 36.0 wt% or no more than 35.5 wt% or no more than 35.0 wt% or no more than 34.5 wt% or no more than 34.0 wt% or no more than 33.5 wt% or no more than 33.0 wt% or no more than

32.5 wt% or no more than 32.0 wt%.

The MgO content of the inorganic fibre composition preferably comprises in the range of 0.1 to 1.7

wt% MgO; or 0.11 wt% to 1.50 wt% MgO; or 0.12 wt% to 0.1.30 wt%; or 0.1 to 1.0 wt% MgO; or 0.11 wt% to 0.90 wt% MgO; or 0.12 wt% to 0.85 wt% MgO; or 0.13 wt% to 0.80 wt% MgO or 0.14 wt% to

0.75 wt% MgO; or 0.17 wt% to 0.72 wt% MgO; or 0.15 wt% to 0.70 wt% MgO; or 0.15 wt% to 0.65

wt% MgO; or 0.17 wt% to 0.60 wt% MgO; or 0.18 wt% to 0.50 wt% MgO; or 0.19 wt% to 0.45 wt%

MgO; or 0.20 wt% to 0.40 wt% MgO.

In one embodiment, the other components comprise:

• 0 or 0.01 to 0.8 wt% A1 20 3 or 0.10 to 0.60 wt% A1 20 3 or 0.20 to 0.55 wt% A1 20 3 or0.23 to 0.50 wt% A12 03 or0.24 to 0.45 wt% A1 2 03 or 0.25 to 0.40 wt% Al 2O 3or0.25 to 0.35 wt%

A120 3;

• 0 to 0.50 wt% alkali metal oxides or 0.01 to 0.45 wt% alkali metal oxides or 0.03 to 0.40

wt% alkali metal oxides or 0.04 to 0.35 wt% alkali metal oxides or 0.05 to 0.30 wt% alkali

metal oxides or 0.06 to 0.25 wt% alkali metal oxides or 0.07 to 0.20 wt% alkali metal

oxides or 0.08 to 0.18 wt% alkali metal oxides;

• 0 to 1.0 wt% TiO 2 or 0.05 to 0.8 wt% TiO 2 or 0.10 to 0.6 wt% TiO 2 or 0.15 to 0.4 wt% TiO 2

or 0 to 0.2 wt% TiO 2; or

0 to 1.0 wt% ZrO 2 or 0.05 to 0.8 wt% ZrO 2 or 0.10 to 0.6 wt% ZrO 2 or 0.15 to 0.4 wt% ZrO2 or 0 to 0.2 wt% ZrO 2 ;

In some embodiments, at least 80 wt% of the alkali metal oxides comprise Na 20 or K 20.

In one embodiment, the range of other incidental impurities in the inorganic fibres is:

BaO: 0 to 0.05 wt% or >0 to 0.01 wt%

B 2 0 3 : 0 to 0.1 wt% or >0 to 0.05 wt%

Cr 2 3 : 0 to 0.08 wt% or >0 to 0.03 wt%

Fe 2 3 : 0 to 0.25 wt% or >0 to 0.15 wt%

Hf 2 : 0 to 0.05 wt% or >0 to 0.01 wt%

La 2 3 : 0 to 0.1 wt% or >0 to 0.03 wt%

Mn 3 0 4 : 0 to 0.05 wt% or >0 to 0.01 wt%

Li20: 0 to 0.15 wt% or >0 to 0.08 wt%

Na 20: 0 to 0.15 wt% or >0 to 0.08 wt%

K 2 0: 0 to 0.5 wt% or >0 to 0.20 wt%

P 2 0 5: 0 to 0.05 wt% or >0 to 0.01 wt%

SrO: 0 to 0.08 wt% or >0 to 0.03 wt%

TiO2: 0 to 0.08 wt% or >0 to 0.03 wt%

V 20 5: 0 to 0.05 wt% or >0 to 0.01 wt%

SnO2: 0 to 0.05 wt% or >0 to 0.01 wt%

ZnO: 0 to 0.05 wt% or >0 to 0.01 wt%

ZrO2 : 0 to 0.1 wt% or >0 to 0.02 wt%

The sum of BaO + Cr O 2 2 3 + HfO 2 + La 2O 3 + Mn 30 4 + Na 20 + K 2 0 + P 2 05 + SrO + SnO 2 + TiO 2 + V 205 3 + Fe O

+ ZrO2 + ZnO is preferably less than 2.0 wt% or less than 1.8 wt% or less than 1.6 wt% or less than 1.4

wt% or less than 1.2 wt% or less than 1.0 wt% or less than 0.8 wt% or less than 0.6 wt% or less than

0.5 wt% or less than 0.4 wt% or less than 0.3wt% or less than 0.25 wt% or less than 0.2 wt% of the

total weight of the inorganic fibres. The sum of BaO + Cr O 2 3 + Fe 2O 3 + HfO 2 + La 2O 3 + Mn 30 4 + Na 20 +

K 2 0 + P2 0 5+ SrO + SnO2 + TiO2 + V 2 0 5+ ZrO 2 + ZnO is typically at least 0.10 wt% or at least 0.20 wt%

or at least 0.30 wt% of the total weight of the inorganic fibres.

In one embodiment, the silica level of the inorganic fibres is configured to inhibit the reactivity of the

inorganic fibres, such that the inorganic fibres are non-reactive with mullite when in contact at

1200°C for 24 hours.

In another one embodiment, the inorganic fibres have a composition comprising:

65.7 to 70.8 wt% SiO 2 ;

27.0 to 32.3 wt% CaO;

0.10 to 2.0 wt% MgO; and

optional other components providing the balance up to 100 wt%,

components, when present, comprise no more than 0.80 A1 20 3

. The fibres of this embodiment are particularly suited to insulations systems in which the inorganic

fibres are configured to be in contact with a refractory component comprising alumina, such as

mullite.

In another embodiment, the inorganic fibres have a composition comprising:

66.0 to 69.0 wt% or (65.7 to 69.0 wt%) SiO 2 or the sumof SiO 2 + ZrO 2;

30.0 to 34.0 wt% CaO or (30.0 to 34.2 wt%) CaO;

0.10 to 0.45 wt% (or 0.1 to 0.45 wt%; or 0.1 to 0.60 wt%) MgO

0 to 0.35 wt% (or 0.1 to 0.35 wt%; or 0 to 0.45 wt%; or 0 to 0.60 wt%) A1 20 3

0 to 0.20 wt% (or 0.05 to 0.18 wt%) alkali metal oxides and

wherein the sum of SiO 2 and CaO is greater or equal to 99.0 wt%.

In some embodiments, the numerical average (or arithmetic mean) fibre diameter is less than 6.0

am or less than 5.0 pm or less than 4.5 pm or less than 4.0am or less than 3.5am or less than 3.3

am or less than 3.0am or less than 2.8 m or less than 2.5 m. Minimum numerical average fibre

diameter is typically at least 1.5 am or at least 2.0am to enable the fibres to have sufficient

mechanical strength in use.

In some embodiments, the shot content (>45lm) of the inorganic fibres is less than 51 wt% or less

than 50 wt% or less than 49 wt% or less than 48 wt% or less than 47 wt% or less than 46 wt% or less

than 45 wt% or less than 44 wt% or less than 43 wt% or less than 42 wt% or less than 41 wt% or less

than 40 wt% or less than 39 wt% or less than 38 wt% or less than 37 wt% or less than 36 wt% or less

than 35 wt% or less than 34 wt% or less than 33 wt%.

A combination of reduced fibre diameter and lower shot content results in improved insulative

properties.

The inorganic fibres may be incorporated into thermal insulation for use in applications preferably

requiring continuous resistance to temperatures of up to 1300°C or in some embodiments 1200°C or

more (e.g. a classification temperature of 1100°C or 1150°C or 1200°C or 1260°C or 1300°C (EN 1094

1-2008)).

In some embodiments, the fibre has a dissolution rate, in the flow solubility test (pH 7.4), is

preferably at least 130 ng/cm2 hr or at least 140 ng/cm 2 hr or at least 150 ng/cm 2 hr or at least 170

ng/cm2 hr or at least 200 ng/cm 2 hr; or at least 250 ng/cm 2hr.

In some embodiments, the tensile strength of the fibre blanket (128 kg/m 3) is at least 50 kPa or at

least 55 kPa or at least 60 kPa. The fibre blanket strength may be determined in accordance to EN

1094-1 (2008).

In some embodiments, the thermal conductivity at 1000°C of a 128 kg/m3 fibre blanket is no more

than 0.30 W.m-'.K-' or no more than 0.28 W.m-'.K-' or more than 0.26 W.m-'.K-' or no more than

0.25 W.m-'.K-'. The fibre blanket thermal conductivity may be determined in accordance to ASTM

C201 - 93 (2019).

The thermal conductivity at 1200°C of a 128 kg/m 3 fibre blanket is preferably no more than 0.35

W.m-'.K-' or no more than 0.32 W.m-'.K-'or no more than 0.31 W.m-'.K-'or no more than 0.30 W.m

'.K- or no more than 0.29 W.m-'.K-'

In some embodiments, the resiliency of the fibre as made is at least 80%. The resiliency after 1100°C for 24 hrs is preferably at least 70 wt% or at least 75 wt%. The resiliency after 1150°C for 24 hrs is

preferably at least 63 wt% or at least 67 wt% or at least 70 wt% or at least 72 wt% or at least 74 wt%.

The resiliency after 1200°C for 24 hrs is preferably at least 60 wt% or least 63 wt% or at least 67 wt%

or at least 70 wt%.

By maintaining the other components (e.g. incidental impurities) within the above limits, the

inorganic fibres of the present disclosure are able to maintain excellent high temperature utility.

While it may be possible for individual impurities levels to vary from their preferred range, through

maintaining an overall low level of incidental impurities, the need for adding additives (e.g. viscosity

modifier, solubility enhancer, refractory temperature stabiliser, etc.) to the calcia and silica mixture

may be avoided or minimised.

Fiberisation techniques as taught in US4,238,213 or US2012/247156 may be used to form the

disclosed fibres of the present disclosure. The apparatus and techniques disclosed in

W02017/121770 (which is incorporated herein in its entirety by reference) may be preferably used, particularly for compositions comprising higher silica contents (e.g. > 68 wt% or > 69 wt%).

In a second aspect of the present disclosure, there is provided an insulation or sealant system comprising:

a. a refractory component comprising a contact surface; and

b. an insulating or sealant material comprising inorganic fibres having a composition of

the first aspect of the invention

wherein the insulating lining or sealant material is disposed against the contact surface.

In some embodiments, the inorganic fibres of the insulation system comprises (i) at least 65.7 wt%

SiO2 ; (ii) at least 65.7 wt% of the sum of SiO 2 + ZrO 2; or (iii) a composition in which the inorganic fibres are non-reactive with mullite when in contact at 1200°C for 24 hours. It would be appreciated by the skilled artisan that the exact compositional window for non-reactivity with mullite may vary

dependent upon the additives or incidental impurities present.

The refractory component may comprise alumina. The refractory component may comprise at least

wt% A12 03 or at least 30 wt% or at least 40 wt% A1 2 0 3 or at least 50 wt% A1 2 0 3 or at least 60 wt%

or at least 70 wt% A1 20 3 . Examples of refractory component compositions include mullite; clay

based compositions or alumina-based compositions. The refractory component may include

refractory mortar, refractory mastic, refractory cement, refractory board, refractory fibre or

refractory bricks.

The sealant material is in the form of mastic, blanket or bulk fibre. The insulating material may be in

the form of a blanket, module, board or bulk fibre.

The insulation or sealant system may form part of a kiln, oven, furnace or other high temperature

apparatus.

In a third aspect of the present disclosure, there is provided a furnace, kiln or oven comprising:

a. a wall comprising an inside surface; and

b. an insulating material comprising inorganic fibres having a composition according to

a first aspect of the present disclosure, wherein the insulating material is attached to an inside surface of the wall, the insulating material in use having a hot face which faces inwardly of the furnace, kiln or oven; and a cold face at, facing, or adjacent the inside surface of the wall.

The inorganic fibres may form part or all of the cold face, which may be in contact with the wall. The

inorganic fibres may also form part or all of the hot face. The inorganic fibres may be in the form a

blanket. The blanket may form a block construction through folding the blanket back and forth.

The wall may have the same composition as other refractory components defined in the second

aspect of the present disclosure.

In a fourth aspect of the present disclosure, there is provided a process for the manufacture of inorganic fibres comprising:

a. selecting a composition and proportion of each of the following raw materials:

i. silica sand and

ii. lime, said lime comprising at least 0.10wt% magnesia; and iii. optional additives

b. mixing the silica sand; lime; and optional additives to form a mixture;

c. melting the mixture in a furnace;

d. shaping the molten mixture into inorganic fibres,

wherein the raw material selection comprises composition selection and proportion selection of

silica sand and lime to obtain an inorganic fibre composition comprising a range of from 61.0 wt%

and 70.8 wt% silica; less than 2.0 wt% magnesia; incidental impurities and no more than 2.0 wt% of

metal oxides and/or metal non-oxides derived from said optional additives; with calcia providing

the balance up to 100 wt% and wherein the inorganic fibre composition comprises no more than

0.80 wt% A12 03 derived from the incidental impurities and/or the optional additives.

In one embodiment, the process produces the inorganic fibre composition of the first aspect of the

present disclosure.

The shaping of the molten mixture into inorganic fibres may comprising forming strands of the

molten mixture and quenching the molten mixture to solidify it.

In embodiments comprising the addition of additives, no more than 1.9 wt% or no more than 1.8

wt% or no more than 1.7 wt% or no more than 1.6 wt% or no more than 1.5 wt% or or no more than

1.4 wt% or no more than 1.3 wt% or no more than 1.2 wt% or or no more than 1.1 wt% or no more

than 1.0 wt% or no more than 0.9 wt% or no more than 0.8 wt% of metal oxides and/or metal non- oxides in the organic fibre composition are derived from said optional additives. Raw materials are inclusive of the optional additives.

In one embodiment, the composition selection and proportion selection of the raw materials is

configured so the amount of magnesia in the inorganic fibre composition is sufficient to inhibit the

formation of surface crystallite grains upon heat treatment at 11000 C for 24 hours, wherein said

surface crystallite grains have an average crystallite size of 0.90 pm or less. The magnesia content of

inorganic fibre composition may be at least 0.08 wt% or at least 0.10 wt%.

In some embodiments, the raw materials consist of silica sand, and lime (i.e. no additives, but

incidental impurities may be present). By restricting the number of raw materials, the carbon footprint

of the process may be reduced. The lime is preferably selected such that the resultant fibre

composition comprises in the range of 0.10 to 2.0 wt% MgO and no more than 0.80 wt% A1 20 3 or as

otherwise defined in the first aspect of the present disclosure.

The composition selection and proportion selection may be configured to obtain the inorganic fibres

compositions of the first aspect of the present disclosure.

In one embodiment, the composition selection of the raw materials involves doping amounts of

selected incidental impurities (e.g. up to 2.0 wt% or up to 3.0 wt%) into the raw materials to

determine the shrinkage of the resultant inorganic fibres when exposed to 1300°C for 24 hrs and

using this information to determine a target composition selection range of the silica sand and lime.

By determining the limits of incidental impurities, a broader arrange of raw material sources may be

used without the need for additional chemical purification.

The composition of the silica sand and/or lime may be obtained through blending different batches

of silica sand and/or lime to obtain the target composition. The target composition may be selected

to control the shrinkage and/or crystallite grain size when the inorganic fibres are exposed to

temperatures of 1100°C or more.

The raw materials preferably have not been chemically purified. Chemical purification includes

chemical leaching or extraction techniques, but may exclude water washing operations. Each of the

raw materials are preferably sourced from a natural mineral deposit.

configured to obtain a vacuum cast preform of the inorganic fibres comprising a shrinkage of 6.0% or

less (or 4.0% or less or 3.5% or less) when exposed to 1300°C for 24 hrs.

configured to obtain an inorganic fibre content comprising at least 65.7 wt% silica.

In some embodiments, the composition selection and proportion selection of the raw materials is

configured such that the inorganic fibres comprise less than 2.0 wt% incidental impurities or less

than 1.5 wt% incidental impurities less than 1.0 wt% incidental impurities or less than 0.8 wt%

incidental impurities or less than 0.6 wt% incidental impurities. The selection of the fuel source may

also be used to control the composition and proportion of incidental impurities (e.g. coal ash levels).

In some embodiments, no more than 3.0 wt% or no more than 2.5 wt% or no more than 2.2 wt% or

no more than 2.0 wt% or no more than 1.8 wt% or no more than 1.5 wt% or no more than 1.2 wt%

of the inorganic fibres are derived from the sum of incidental impurities and optional additives.

Preferably the sum of magnesia and incidental impurities is greater or equal to 0.3 wt% or greater or

equal to 0.4 wt%. The amount of magnesia and incidental impurities being sufficient to reduce the

melt viscosity of the composition and enable fibres to be formed as described in previous aspects of

the disclosure.

In a fifth aspect of the present disclosure, there is provided inorganic fibres obtained or obtainable

by the process according to the fourth aspect of the present disclosure.

It should be understood that usage in compositions of the names of oxides [e.g. alumina, silica,

potassia] does not imply that these materials are supplied as such, but refers to the composition of

the final fibre expressing the relevant elements as oxides. The materials concerned may be provided

in whole or in part as mixed oxides, compounded with fugitive components [e.g. supplied as

carbonates] or indeed as non-oxide components [e.g. as halides].

Incidental impurities are defined as impurities which are derived from the raw material, fuel source

or other sources during the formation of the inorganic fibres. Material composition is determined on

a dry weight basis.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a SEM image of a fibre from sample 24

Figure 2 is a SEM image of a fibre of the prior art (sample 23)

Figures 3a & 3b are SEM images of a fibre from sample 19

Figure 3c is a SEM image of a fibre from sample 31

Figure 3d is a SEM image of a fibre from sample 29

Figure 4a is a SEM image of a fibre from sample 22

Figure 4b is a SEM image of a fibre from sample 20

Figure 4c is a SEM image of a fibre from sample 4

Figure 4d are a SEM images of a fibre from sample 36

Figure 5a is a SEM image of a fibre from sample 8

Figure 5b is a SEM image of sample 26

Figure 6 is a schematic diagram of bake furnace sealant system

Figure 7 is a schematic diagram of a furnace lined with inorganic fibres of the present disclosure.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Fibres according to the disclosure and comparative fibres described herein have been produced at

either the French production facilities in Saint Marcellin, France by spinning [made from the melt by

forming a molten stream and converting the stream into fibre by permitting the stream to contact

one or more spinning wheels]; or at the applicant's research facilities in Bromborough, England by

spinning or alternatively by blowing [fibres made from the melt by forming a molten stream and

converting the stream into fibre by using an air blast directed at the stream]. The disclosure is not limited to any particular method of forming the fibres from a melt, and other methods [e.g. rotary or

centrifugal formation of fibres; drawing; air jet attenuation] may be used. The resultant fibres were

then fed onto a conveyor belt and entangled by needling methods, as known in the art.

The raw materials used to produce the inorganic fibres of a preferred embodiment of the present disclosure are lime and silica sand. The chemical analysis (normalised) of the lime used is provided in

Table 1 below. The incidental impurities (100 - CaO - SiO2 ) in the lime is typically less than 2.0 wt%.

The silica sand purity may be 98.5 wt% of 99.0 wt% or higher. Typically, the silica sand had a purity

of greater than 99.5 wt% silica and less than 200 ppm Fe O 2 3 ; less than 1000 ppm A1 20 3 ; less than 200

ppm TiO2 , less than 100 ppm CaO and less than 100 ppm K 2 0.

Some of the compositions produced had elevated K 20 levels due to the additional of fluxing agents in

the pilot scale furnace in Bromborough or due to cross-contamination from previous production in

the Saint Marcellin furnace. Amongst others, samples P61-0481 and P61-0488 are representative of

compositions produced from the raw materials of silica sand and lime only.

Table 1

Lime bag CaO A1 2 0 3 Fe 2 0 3 K20 MgO SiO 2 ZrO 2 Un-normalised XRF total

BI 97.97 0.28 0.21 0.04 0.41 1.09 0.01 98.39 B2 98.12 0.30 0.21 0.04 0.38 0.93 0.00 99.17 B3 97.79 0.30 0.21 0.04 0.37 1.26 0.02 99.39 B4 97.56 0.35 0.21 0.04 0.38 1.43 0.01 99.00 B5 97.64 0.54 0.21 0.04 0.38 1.15 0.01 99.94 B6 97.61 0.49 0.22 0.04 0.41 1.15 0.04 99.92 B7 97.97 0.33 0.20 0.04 0.40 1.01 0.01 98.93 B8 95.15 0.34 0.20 0.04 0.40 3.85 0.00 99.94

The fibres/blankets made therefrom were then evaluated using the test methodology as described:

Test methodology

The EN 1094-1-2008 standard was used for the shrinkage, tensile strength and resiliency tests.

Shot content

Shot content was determined by a jet sieve method as detailed in W02017/121770, incorporated

herein by reference.

Thermal Stability (Shrinkage)

The method for determination of dimensional stability of refractory materials, including the refractory

glass fibre insulation materials, is based on the EN ISO 10635. This method is a shrinkage test that

measures the change of a flat specimen's linear dimensions after a heat treatment.

The shrinkage test requires a relatively rigid specimen's so that the linear dimensions could be

accurately determined before and after the heat treatment. In cases where a needled fibre blanket

specimen were not available, starch bonded vacuum formed boards were prepared from the glass

fibre samples.

To prepare the vacuum formed boards, the as made fibre material were chopped using a small-scale

industrial granulator through a #6 mesh (~3mm opening). Chopped fibre samples were lightly cleaned

using a sieve to remove any debris and large glass residues. 40g of chopped clean fibre was mixed in

500 ml of 5 wt% concentration potato starch in water solution to create a slurry. Subsequently a

vacuum former was used to produce 75x75 mm boards with a thickness of 10-15 mm. The vacuum former consists of a sealed acrylic mould with a 100 pm mesh bottom, a vacuum pump was used to

remove the water from the slurry while manually compressing the shape using a flat plate. Vacuum

formed boards were dried at 120°C.

To measure permanent linear shrinkage, the linear dimensions of specimen were measured to an

accuracy of ±5 m using a travelling microscope. The specimens were subsequently placed in a furnace

and ramped to a temperature 50°C below the test temperature (e.g. 1300°C) at a rate of 300°C/hour

and then ramped at 120°C/hour for the last 50°C to test temperature and held for 24 hours. Specimens

were allowed to cool down naturally to room temperature at the end of this heat treatment. After

heat treatment, the specimen's linear dimensions were measured again using the same apparatus to

calculate the change in dimensions. Shrinkage values are given as an average of 4 measurements.

Reactivity with Mullite

Needled fibre blanket specimens with approximate dimensions of 50mm x 100mm were used for this

test. Blanket specimens were placed on a fresh mullite Insulating Fire Brick (JM 28 IFB). The

specimen, along with the IFB substrate, was heated treated at 12000 C for 24 hours to confirm the

reactivity after the heat treatment. The specimen and IFB were inspected for any sign of melting or

reaction. The sample which did not react with the IFB at all were evaluated as good (0). The sample

which reacted with the IFB (the sample was adhered to IFB or sign of melting was observed) were

evaluated as poor (X).

Bio-solubility

The biological solubility of fibrous materials can be estimated in a system in which the material is

exposed to a simulated body fluid in a flow-through apparatus (i.e., in vitro). This measurement of

solubility is defined as the rate of decrease of mass per unit surface area (Kdis). Although several

attempts have been made to standardize this measurement, there is currently no international

standard. Major protocol differences among laboratories include different simulated body fluid

chemistries (and, most significantly, different buffering and organic components), flow rates, mass

and/or surface area of samples, determination methods for specific surface area, and determination

of mass loss. Consequently, Kdis values should be regarded as relative estimates of chemical reactivity

with the simulated body fluid under the specific parameters of the test, not as measures of absolute

solubility of fibrous particles in the human lung. The flow through solubility test method used in this

study is a 3-week long solubility test in pH 7.4 saline. Two channels of each unique specimen are

simultaneously tested. Samples of saline solution flowing over the fibre specimens are taken after 1, 4, 7, 11, 14, 19 and 21 days. The saline samples are analysed using the ICP method to measure the

oxide dissolution levels in ppm level. To validate the flow test results and calculate the final dissolution

rates for each specimen, the square root of remaining fibre mass against sampling times are plotted.

Deviation from a linear trend could suggest an issue with the results. A good linear regression fit was

observed in the flow test results conducted in this study. Based on the historical data collected by authors, a minimum of 150 ng/cm 2hr dissolution rate is typically required for a fibre to have exoneration potential. In the static solubility test method, fibre specimens are agitated in saline solution at 37°C to replicate conditions within the lungs. The test monitors fibre dissolution after 24 hours using the ICP method. Si02 and CaO typically make up the majority of the dissolution material.

Resiliency

The resiliency test (EN1094-1-2008) demonstrates the ability of fibre insulation products to spring back after being compressed to 50 % of their initial thickness. Samples for resiliency testing in this

document were in needled blanket form. As made or heat treated blanket specimens were cut to

100 mm x 100 mm squares and dried at 110 C ±5 °C for 12 hours to remove any absorbed moisture.

Specimens were subsequently allowed to cool to room temperature and then test immediately. The

initial thickness of blanket specimens were measured using the pin and disk method prior to

resiliency testing. An Instron universal mechanical test frame, equipped with 150 mm diameter flat

compression platens was used for the resiliency tests. During the test, the specimens were

compressed to 50 %of their original thickness at a rate of 2 mm/min, the specimens were then held

under compression for 5 minutes. Subsequently the specimens were allowed to spring back by lifting

the compression platen until 725 Pa (for specimens > 96 kg/m3 bulk density) or 350 Pa (for

specimens <96 kg/m3 bulk density) was registered on the load cell and then held for a further 5

minutes. Following this test, the resiliency values were calculated using the formula below:

R= dfx100 do

R= Resiliency

df =Thickness after testing

do =Initial Thickness

Tensile Strength

The parting strength of a blanket is determined by causing rupture of test pieces at room temperature.

Samples are cut using a template (230 ±5mm x 75 ±2mm). The samples are dried at 110°C to a constant

mass, cooled to room temperature and then measured and tested immediately.

The width is measured using a steel rule to a 1mm accuracy across the middle of the piece and the

thickness of the sample is measured on each sample (at both ends of the sample) using the EN1094-1

needle method. A minimum of 4 samples for each test are taken along the direction of manufacture.

The samples are clamped at each end by clamps comprising a pair of jaws having at least 40mm x

mm in clamping area with serrated clamping surfaces to prevent slippage during the test. These dimensions give an unclamped span of 150 ±5mm to be tested. The clamps are closed to 50% of the sample thickness (measured using a Vernier caliper or ruler).

The clamps are mounted in a tensile testing machine [e.g. Instron 5582, 3365 using a 1kN load cell, or

a machine of at least the equivalent functionality for testing tensile strength]. The crosshead speed of

the tensile testing machine is a constant 100mm/min throughout the test. Any measurement with the

sample breaking nearer to the clamp jaw than to the centre of the sample is rejected.

The maximum load during the test is recorded to allow strength to be calculated.

Tensile strength is given by the formula:

F R(m) =F WXt Where:

R(m) = Tensile Strength (kPa)

F= Maximum Parting Force (N)

W= Initial Width of the active part of the test piece (mm)

T= Initial Thickness of test piece (mm)

The test result is expressed as the mean of these tensile strength measurements together with the

bulk density of the product.

Fibre diameter

Fibre diameter measurements were carried out using the Scanning Electron Microscope (SEM). SEM

is a micro-analytical technique used to conduct high magnification observation of materials'

microscopic details. SEM uses a tungsten filament to generate an electron beam, the electron beam is

then rastered over a selected area of the specimen and the signal produced by the specimen is

recorded by a detector and processed into an image display on a computer. A variety of detectors can

be used to record the signal produced by the sample including secondary electrons and backscattered

electrons detectors.

The particularSEM equipment used operates under vacuum and on electrically conductive specimens.

Therefore, all glass/ceramic fibre specimens need to be coated with gold or carbon prior to SEM

analysis. Coating was applied using an automated sputter coater at approximately 20 nm. In order to

prepare the fibrous specimens for diameter measurements, fibre specimens were crushed using a

pneumatic press at 400 psi. The aim of crushing is to ensure the sample is crushed enough to be

dispersed without compromising the fibre length, crushing results in fibres with aspect ratios >3:1. The crushed fibre specimens is then cone and quartered to ensure representative sampling. Crushed and quartered fibres are dispersed in IPA. Typically, 50 ig of fibres are placed in a 50 mL centrifuge tube and 25 mL IPA is added. A SEM stub is then placed at centre of a petri dish, then the centrifuge tube is vigorously shaken and emptied into the petri dish containing the SEM stub. The petri dish is left in fume cupboard for 1 hour for the fibres to settle on the SEM stub. The SEM stub is then carefully coated with gold in preparation for SEM imaging.

Following this sample preparation step, an automated software on the SEM equipment is utilised to

collect 350 unique secondary electron images at 1500x magnification from the SEM stub. Following

the image collection step, the images are processed by the Scandium* system available from Olympus

Soft Imaging Solutions GmbH, to measure the diameter of fibres. The process involves manual

inspection of measured fibres in every image to ensure only the fibres particles with aspect ratios

greater than 3:1 are measured. The final fibre diameter distribution is reposted in a graph as well as

numerical average/arithmetic mean diameter.

Crystallite grain size

Crystallite grain size measurements on heat treated fibre materials were carried out using the Scanning

Electron Microscope (SEM). SEM is a micro-analytical technique used to conduct high magnification

observation of materials' microscopic details. SEM uses a tungsten filament to generate an electron

beam, the electron beam is then rastered over a selected area of the specimen and the signal produced

by the specimen is recorded by a detector and processed into an image display on a computer. A

variety of detectors can be used to record the signal produced by the sample including secondary

electrons and backscattered electrons detectors.

The particular SEM equipment used operates under vacuum and on electrically conductive specimens.

analysis. Coating was applied using a automated sputter coater at approximately 20 nm. In order to

prepare the fibrous specimens for grain size measurements, fibre specimens were cone and quartered

to ensure representative sampling. A SEM stub is prepared with a small representative sample of the

specimen and carefully coated with gold in preparation for SEM imaging.

Following this sample preparation step, the SEM equipment is utilised to collect several unique

secondary electron images at suitable magnification based on morphology (typically in 5000-10000x

magnification range) from the SEM stub. Following the image collection step, the images are processed

by a computer software program (Olympus Scandium*) to measure the grain size by drawing circles

around the visible grain boundaries in several SEM images. The process involves manual inspection of fibres in every image to ensure only the fibres are in focus. The final grain size is reported as numerical average of all measurements (preferably a minimum of 10 measurements of representative crystals).

Preferably, the crystallite size is determined from a random selection of at least five fibres, with

measurements of representative crystallite sizes of 5 grains taken from each fibre. Fibre

measurements falling more than 2 standard deviations from the mean are to be disregarded. Due to

limitations in magnification and resolution of SEM images, the minimum measurable grain size was

about 0.4 pm. Samples with lower crystallite grain sizes were reported as having a mean grain size

value <0.4ptm.

Crystalline grains are differentiated from other surface imperfections by their regularity in frequency

and shape, which is characterized by the crystallites protruding from the surface of the fibre, as

indicated in the increase grain sizes from Figures 4a to Figure 4d. Surface imperfections include

irregular shaped platelet formations as illustrated on Figures 3b and 3d.

Melting temperature

The melting temperature of the fibres was determined by DSC (10k/min temperature increase from

°C to 1500°C). Sample 26b (50mg of fine powder ground from fibre) had a melting temperature of

1435.3°C.

Fibre composition

Fibre composition was determined using standard XRF methodology. Results were normalised after

analysis performed on Si0 2 , CaO, K 20, A120 3, MgO and oxide components listed in Table 6. Un

normalised results were discarded if the total weight of the composition fell outside the range 98.0 wt% to 102.0 wt%.

Effects of impurities

To assess the effects of the incidental impurities in the raw materials, an ultra pure sample (C-24)

was produced using a silica (Si2: 99.951 wt%, A 2 0 3 : 0.038wt% Fe 2 0 3 : 0.012 wt%) and calcia (CaO:

99.935 wt%, Si0 2 : 0.011 wt%, Al20 3 : 0.012wt% Fe 2 0 3 : 0.011 wt%, SrO: 0.031 wt%). The remaining

components were less than the XRF detection limit (<0.01 wt%).

To assess the effect of impurities, additional amounts of A 2 0 3, MgO, TiO 2 and ZrO 2 were added to

the existing incidental impurities. With reference to Table 4a, increasing amounts of MgO, TiO 2 and

Al203 results in reduced thermal stability at 1300C (24 hrs), as measured by the % shrinkage.

Example 34 is a near repetition of sample E-174 from US5,332, 699.

Table 2

Sample Si02 CaO A12 0 3 K 20 MgO CaO+SiO 2 C-1 72.8 24.9 1.1 0.6 0.6 97.7 C-2 71.2 28.1 0.33 0.06 0.17 99.3 1 70.7 28.8 0.26 0.03 0.13 99.5 2 70.6 28.9 0.28 0.04 0.16 99.5 3 70.6 28.5 0.55 0.12 0.19 99.1 4 70.5 28.4 0.69 0.18 0.23 98.9 5 70.3 29.1 0.36 0.05 0.17 99.4 6 69.5 30.0 0.27 0.04 0.15 99.5 7 69.4 30.1 0.32 0.03 0.15 99.5 8 67.7 31.9 0.25 0.03 0.15 99.6 9 67.1 32.4 0.28 0.02 0.15 99.5 10 66.0 33.1 0.60 0.04 0.18 99.1 11 65.7 33.8 0.22 0.03 0.15 99.5 12 65.6 34.0 0.27 0.02 0.15 99.6 13 65.3 34.2 0.23 0.03 0.16 99.5 14 65.0 34.5 0.35 0.02 0.17 99.5 15 64.5 35.1 0.19 0.06 0.16 99.6 16 63.3 36.1 0.22 0.10 0.29 99.4 17 62.8 36.7 0.23 0.07 0.16 99.5 18 61.5 38.0 0.21 0.09 0.16 99.5 19 67.2 32.3 0.07 0.02 0.23 99.5 20 69.0 30.2 0.49 0.03 0.23 99.2 21 66.0 33.5 0.18 0.02 0.32 99.5 22 66.3 33.2 0.19 0.01 0.26 99.5 C-23 66.3 33.2 - 0.004 0.03 99.5 C-24 65.8 34.2 0.02 0.0 0.0 100.0 25 63.3 36.1 0.22 0.10 0.29 99.4 26 68.0 31.3 0.18 0.27 0.21 99.3 26b 67.1 32.4 0.23 0.10 0.15 99.5 P61-0488 66.2 33.3 0.15 0.01 0.26 99.5 P61-0481 65.9 33.5 0.15 0.01 0.39 99.4 C-3 60.7 38.9 0.26 0.07 0.17 99.6 C-4 64.9 29.8 0.15 0.01 5.2 94.7 C-5 60.7 38.8 0.23 0.12 0.17 99.5

Results

Referring to Table 2 & 3, there is shown the composition of inorganic fibres as % weight of the total

composition according to Examples 1 to 26b, P61-0481, P61-0488 and Comparative Examples CI to

C5; C-27, C-34-C36. As illustrated in Table 3, inorganic fibre compositions with silica levels less than

65.7 wt% were found to be not compatible with mullite based bricks, adhering to the bricks after

being in contact at 1200°C for 24hrs. Inorganic fibre compositions with higher silica levels had

generally higher shot content and higher fibre diameter. The results from sample P50 indicates that

ZrO2 may be able to partially substitute SiO 2 in the glassy forming network, with these samples also

being compatible with mullite based bricks despite the low SiO2 content of the samples. The

incorporation of a small portion (e.g. up to 2.0 wt% or up to 1.5 wt%) ZrO 2 within the glassy network

is likely to maintain the non-reactive nature of the composition to mullite based bricks or other

alumina based compositions.

Table 3

Sample Mullite Shrinkage at Shot content Mean Fibre Reactivity @ 1300°C (24 hrs) % wt diameter (Vm) 12000 C C-1 0 2.0 - 6.9 C-2 0 1.4 59.3 1 - 0.9 51.9 5.7 2 0 1.4 52.0 3 0 2.2 54.5 4 0 2.7 53.4 2.67 5 0 1.1 50.6 6 0 - 49.5 7 0 1.2 47.8 8 0 2.0 34.6 9 0 1.4 47.3 10 0 1.2 36.6 3.02 11 0 0.8 37.7 12 X 1.3 37.4 3.33 13 X 2.0 39.7 14 X - 38.2 2.87 15 - 2.2 - 16 - 1.7 - 17 - 2.6 - 18 - 3.3 - 19 - 2.1 - 20 - 1.7 - 21 - 1.6 - 2.65 22 - 1.1 - 2.37 25 - 1.7 - 26 - 2.0 - P50 0 5.3 - C-3 - 8.6 - C-4 X 14.5 - C-5 5.6 - -

Shrinkage @ 1300 0Cfor 24 hours

The lowest shrinkage (best high temperature performance) was observed in samples 32 & 33.

Sample 33 was a control sample with no additives, whereas Sample 32 has a slightly elevated MgO

level, although in both samples, the sum of Si02 and CaO is greater than 99.0 wt%. Sample 32

appears to be an anomaly in the correlation between shrinkage and MgO content of Samples 30 to

33. Likewise, Example 37 is also considered a suspect result, with the shrinkage result expected to

be below 4%. The results indicate that, in general, a higher CaO + Si02 level corresponds to fibre

compositions with improved high temperature stability as measured by the shrinkage test.

Surface crystallite size

The ultra-pure raw materials were difficult to form fibres and when fibres were formed, yield was

low and fibre diameter was large (e.g. >500ptm). As illustrated in Figure 1, The surface of the fibres

contain a mean crystallire grain size approaching 5 pm, with cracking also observed. The prevalence

of surface crystallites was also noted on the high purity sample of the prior art (Figure 2; Sample C

23), with a mean crystallite grain size of about 1 m.

Table 4a # Si0 2 CaO A1 20 3 K2 0 MgO ZrO 2 TiO 2 CaO+ Static Shrinkage Solubility at 1300°C SiO2 (pH 7.4) ppm C-27 59.9 35.2 0.34 0.10 4.31 0.00 - 95.1 380 24.1 28 62.4 35.4 0.24 0.13 1.66 0.00 - 97.8 265 6.1 29 62.6 35.7 0.23 0.06 1.35 0.00 - 98.3 375 11.3 30 65.7 33.1 0.19 0.09 0.97 0.00 - 98.8 294 7.0 31 65.4 33.4 0.20 0.08 0.82 0.00 - 98.8 270 3.4 32 66.1 33.0 0.19 0.10 0.56 0.00 - 99.1 289 1.7 33 66.1 33.4 0.18 0.05 0.25 0.00 - 99.5 548 2.6 C-34 63.4 34.9 0.84 0.08 0.47 0.32 - 98.3 301 5.7 C-35 65.5 32.6 1.48 0.13 0.21 0.00 - 98.1 167 6.6 C-36 65.5 33.1 1.04 0.18 0.20 0.00 - 98.6 208 4.1 37 65.5 33.6 0.56 0.14 0.26 0.00 - 99.1 249 5.0 P40 66.0 31.8 0.45 0.04 0.79 0.71 0.03 97.8 140 4.0 P41 66.4 31.8 0.17 0.04 0.89 0.03 0.66 98.2 235 5.5 P47 67.2 31.8 0.17 0.41 0.24 0.03 0.02 99.0 259 1.9 C-P50 63.5 28.6 0.17 0.31 0.23 7.2 0.03 92.1 50 5.3

As indicated in Table 4a, higher totals of CaO + Si02 tend to correspond to higher high temperature

performance and bio-solubility. Table 4b further discloses the correlation between high temperature performance and the MgO content, with lower MgO contents correlating with lower shrinkage of the fibres at 1300°C.

Static solubility

As indicated in Table 4a, increasing amounts of ZrO 2 (see samples C-32, P40 and C-P50) results in a

reduction in bio-solubility of the fibres.

Table 4b

# Si0 2 CaO A12 0 3 K2 0 MgO ZrO 2 CaO+SiO 2 Shrinkage at 1300°C 38 65.36 33.72 0.17 0.02 0.76 0.00 99.09 3.8 39 65.20 34.05 0.16 0.01 0.58 0.00 99.25 2.7 40 65.23 34.12 0.15 0.01 0.51 0.00 99.35 2.2 41 65.50 33.65 0.16 0.01 0.66 0.00 99.15 3.2 42 65.44 33.77 0.14 0.01 0.58 0.01 99.21 2.9 43 65.43 33.88 0.14 0.01 0.52 0.01 99.31 2.2 44 65.46 33.87 0.15 0.01 0.47 0.01 99.33 3.1 45 65.56 33.75 0.24 0.02 0.41 0.02 99.31 2.2 46 65.51 33.90 0.14 0.01 0.37 0.01 99.41 2.1 47 65.72 33.68 0.18 0.01 0.36 0.01 99.40 1.8 48 65.87 33.59 0.17 0.02 0.32 0.01 99.45 1.8 49 65.93 33.48 0.15 0.01 0.39 0.01 99.41 1.9 50 65.98 33.46 0.18 0.02 0.32 0.01 99.43 1.6 51 66.16 33.36 0.15 0.01 0.29 0.01 99.52 1.4 52 66.33 33.25 0.14 0.01 0.27 0.01 99.58 1.2 53 66.25 33.30 0.15 0.01 0.26 0.01 99.55 1.4 54 65.56 33.84 0.14 0.01 0.41 0.01 99.40 1.3 55 66.26 33.22 0.19 0.01 0.26 0.01 99.48 1.1

The effect of the additional of MgO is illustrated in Figures 3a to 3d, with sample 19 (Figures 3a & 3b)

and sample 31 (figure 4) representing a composition with MgO being the predominant minor oxide

component. Figure 3b & 3d also illustrate examples of surface imperfections, including surface

platelets, which are distinct from the regularity and form of the crystallites of Figure 2. The results

indicate that MgO up to at least 4.3 wt% is able to suppress crystallite growth at 1100°C, although

increasing MgO levels also result in an increase in fibre shrinkage, with MgO contents in excess of 2

wt% being less suitable for continuous use applications at or above 1200°C (Table 5). The effect of

increased levels of A12 03 are illustrated in Figures 4a to 4d, with a mean crystallite size of almost 1

pm obtained with an A1 2 03 content of 1.04 wt% (sample 36), with CaO + SiO2 wt% of 98.6 wt%. The

effect of K 2 0 content is illustrated in Figures 5a (sample 8) and 5b (sample 26), with the increase in

K 2 0 content from 0.03 wt% (sample 8) to 0.27 wt% (sample 26) corresponding to a slight increase in crystallite size from below the detection limit (< 0.4 pm) to 0.54 pm. Although samples P42 and P47 indicate elevated levels of K 20 up to about 0.5 wt% are still able to obtain a low crystallite size (< 0.4 pm) for their compositional matrix.

The addition of 0.66 wt% TiO 2 and 0.89 wt% MgO (P41) resulted in poor shrinkage performance at

1300°C, with the TiO2 component appearing to contribute most to this result. P40 had a similar MgO

content to P41, but with ZrO 2 additional having a lower impact compared to TiO 2 upon shrinkage

performance at 1300°C. Whilst the effect of an additive/impurity or combinations thereof may be

specific to the additive/impurity, the inorganic fibre composition may be readily configured, through

testing the sensitivity of additives/impurities, to obtain the required high temperature performance

in terms or shrinkage and/or grain crystallite size.

Table 5

Example Shrinkage at Shrinkage at Grain size (rm) @ % wt of largest 1200°C (24 hrs) 1300°C (24 hrs) 1100°C (24hrs) minor component 4 - 2.7 0.47 0.69 A1 20 3 7 - 1.2 <0.4 0.32 A1 20 3 8 - 0.8 <0.4 0.25 A1 20 3 11 - 1.4 <0.4 0.22 A1 20 3 19 - 2.1 <0.4 0.23 MgO 20 - 1.7 0.48 0.49 A1 20 3 21 - 1.6 <0.4 0.32 A1 20 3 22 - 1.1 <0.4 0.26 A1 20 3 C-23 - - 0.94 0.03 MgO C-24 - - 4.93 0.02 A1 20 3 25 - 1.7 0.48 0.29 MgO 26 - 2.0 0.54 0.27 K 20 27 10.6 24.1 <0.4 4.31 MgO 28 3.4 6.1 <0.4 1.66 MgO 29 4.5 11.3 <0.4 1.35 MgO 30 1.5 7.0 <0.4 0.97 MgO 31 - 3.4 <0.4 0.82 MgO 32 - 1.7 <0.4 0.56 MgO 33 - 2.6 - 0.2 MgO C-34 - 5.7 0.94 0.84 A1 20 3 C-35 - 6.6 - 1.48 A1 20 3 C-36 - 4.1 0.90 1.04 A1 20 3 37 - 5.0 0.51 0.56 A1 20 3 P40 1.4 4.0 0.53 0.79 MgO P41 1.8 5.5 0.77 0.89 MgO P47 1.1 1.9 <0.4 0.41K 20

The results confirm that either too little or too much minor components within the composition may

lead to elevated crystallite size, which is related to a deterioration in high temperature mechanical

performance. In particular, MgO has been shown to inhibit crystallite growth, whilst A1 20 3 has been

demonstrated to promote crystallite growth. Apart from the main incidental impurities of A1 20 3

, MgO and K 20, the XRF analysis measured the metal oxides listed in Table 6. The maximum and

minimum incidental impurity level of each of the metal oxides is provided. Typically, these minor

incidental impurities are less than 0.3 wt% or less than 0.25 wt% or less than 0.20 wt%; and at least

0.10 wt%.

The person skilled in the art may readily determine the levels of specific or groups or specific other

components at which crystallite growth is promoted, without undue experimentation. Raw

materials with varying other components (i.e. impurity) profiles may be used, when other

components detrimental to crystallite growth, and hence high temperature performance, are

controlled to designated levels.

As such, the inorganic fibre composition may be configured to obtain the formation of surface

crystallite grains, upon heat treatment at 11000 C for 24 hours, having an average crystallite size of

0.90 Iim or less.

Table 6 Incidental impurities Maxlevel(%wt) Min level(%wt) BaO 0.01 0.00 Cr 2O 3 0.02 0.00 Fe 2O 3 0.13 0.08 HfO 2 0.00 0.00 La 2O 3 0.07 0.00 Mn 30 4 0.00 0.00 Na 20 0.03 0.00 P 20 5 0.00 0.00 SrO 0.03 0.00 TiO 2 0.03 0.00 V 205 0.01 0.00 SnO 2 0.01 0.00 ZnO 0.00 0.00 ZrO 2 0.03 0.00

Thermal conductivity of bodies of inorganic fibres

Thermal conductivity of a body of melt formed fibres (e.g. a blanket or other product form) is

determined by a number of factors including in particular:-

• Diameter of the fibres; and

• "Shot" (unfiberised material) content

Fine diameter fibres provide low thermal conductivity to a body of fibres by reducing the scope for

conduction through the solid and permitting finer inter-fibre porosity increasing the number of

radiate-absorb steps for heat to pass by radiation from one side of the body to the other.

The presence of shot in a blanket increases thermal conductivity of the blanket by increasing the

scope for conduction through the solid. Shot also increases the density of a blanket. All else being

equal, the lower the shot content, the lower the thermal conductivity and density. For two bodies of identical fibre content and chemistry, the body with the lower shot content will have both the lower

density and lower thermal conductivity.

In reference to Table 7, inorganic fibres were produced with a fibre diameter between approximately

2.6 to 3.0 pm and a shot content between 32 and 41 wt%. From thedataset provided in Tables 7

& 8, there is no clear correlation between fibre characteristics and thermal conductivity, although

samples P61-0481 and P61-0488, with the lowest thermal conductivity, were obtained from a

commercial production line with lower shot level and an expected greater consistency in fibre

diameter of about 3 pm diameter. Blankets derived from inorganic fibres with high Si02 content

would be expected to have higher thermal conductivities due to the high shot content and fibre

diameters associated with these compositions, as illustrated in Table 3. The resiliency of the

inorganic fibres (Table 7) were seen to generally increase with increasing Si02 content.

Sample P61-0488 was produced at the Saint Marcellin site using melt spinning technology at

commercial scale, with production conditions optimised to reduce shot levels, which have an effect

on the insulative properties of the fibre. The inorganic fibre may be formed into an entangled

blanket, typically using a needling technique. Blankets are usually produced at density of at least 64

kg/m 3, with standard commercial densities producible, such as 64 kg/m 3, 96 kg/m 3, 128 kg/m 3, 160

kg/m 3. The inorganic fibre may also be formed into high density modules up to 240 kg/m 3 . Table 9 illustrates the improvement in the insulative properties of a 128 kg/m3 blanket compared on a

blanket produced from comparative example, C-1. The disclosed compositions of the present

disclosure are able to form low fibre diameters and possess low shot content, contributing the

excellent high temperature thermal insulative properties.

Table 7

Shot SEM Fibre Resiliency Resiliency (>45pm) diameter (24hr @1150°C) (24hr @1200°C) SAMPLE % wt (pm) %

% 8 34.6 - 69 64 10 36.6 3.02 69 66 12 32.5 2.65 68 66 13 40.6 - 68 63 14 38.3 2.70 64 60 15 38.7 2.76 - P61-0488 32.1 3.01

Table 8

Conductivity (W/m.K) (ASTM C201) SAMPLE 400° 600° 800° 1000° 1100 1200° Density Strength Density Kg/m 3 kPa Kg/m 3 10 0.08 0.13 0.22 0.33 0.40 0.47 88 35 91

12 0.07 0.12 0.21 0.32 0.39 0.46 96 50 95

13 0.08 0.13 0.20 0.28 0.33 0.39 111 50 121

14 0.07 0.11 0.18 0.27 0.33 0.39 105 48 115

15 0.07 0.12 0.19 0.29 0.35 0.41 105 56 123

P61-0488 0.07 0.11 0.17 0.24 0.28 0.32 128 60 132

P61-0481 0.08 0.12 0.17 0.22 0.26 0.29 128 64 135

Heat flow test (ASTM C680-19 heat flow)

The insulation properties of a 128kg/m 3 200mm thick blanket made from the composition of sample

P61-0488 and C-I was prepared a heat source was applied to one side of the blanket to evaluate the

temperature of at the "hot face" to 100 0 C. The opposing side of the blanket which was initially held

at 27°C ambient temperature, with no wind. After heating of the hot face to 100 0 C, the opposing

surface of the blanket (cold face) was recorded in Table 9. The results indicate the composition of

the present disclosure achieves a reduction in heat loss of 15%.

Table 9

2 Sample Cold face temperature (°C) Heat loss W/m

P61-0488 73 553

C-i 80 653

Bio-solubility

Referring now to Table 10, there is shown data for bio-solubility testing. A 21 day static and long flow through solubility test in saline pH 7.4 was conducted on the compositions shown in Table 10.

Two samples of each fibre composition were simultaneously tested, with the average results

reported. The saline samples were analysed using the ICP method to measure the oxide dissolution

levels in ppm level. The results confirm that the fibres have low biopersistence. A low biopersistence

fibre composition is taken to be a fibre composition which has a dissolution rate, in the flow

solubility test, of at least 150 ng/cm 2 hr or at least 170 ng/cm2 hr or at least 200 ng/cm 2 hr.

The inorganic fibres under the present disclosure have comparable or improved bio-solubility in

comparison with prior art fibre compositions C1 and C2. As indicated by the specific surface area

measurements, fine fibre dimensions promote increased bio-solubility.

Summary of results

The above results highlight that the fibre composition of the present disclosure is able to produce a

refractory fibre with great utility without the need for the deliberate additional of significant

amounts of additives to enhance one or more fibre properties. This unexpected result also enables refractory fibres to be produced with a lower carbon footprint due to the reduced number of raw

materials required for its production.

Table 10

Static Flow through SpecificSurface Sample Solubility Dissolution Rate Area Description (pH 7.4 saline) (pH 7.4 saline) (total ppm) (ng/cm 2hr) (m 2 /g)

C-1 230 125 0.1652

C-2 313 379 0.2526

11 378 348 0.2887

16 295 326 0.3375

17 370 -

18 208 -

19 333 -

20 292 -

26 473 - -

Insulation or sealant systems

In some embodiments, the fibre of the present disclosure may be used as an insulation and/or sealant system in kilns, ovens and furnaces or other high temperature environments. The insulation

or sealant system may comprise a layer of alumina rich material (e.g. mullite or refractory bricks) and

a layer (e.g. blanket) of inorganic fibres. Insulation systems may be used in kilns used for:

• glass and ceramic goods production;

• chemical and petrochemical processes;

• iron and steel production and transformation facilities; and

* non ferrous metal production and transformation facilities

The fibre may also be used as insulation in heat shields and pollution devices (e.g. catalytic

converters), where the non-reactivity of the fibres is beneficial.

With reference to Figure 6, there is an illustration of a sealant system from a section of a carbon

bake furnace comprising a flue wall 100 and a headwall 110. A refractory mastic comprising inorganic

fibre of the present disclosure is used as a corner seal 120 to prevent coke from the bake pit (not

shown) from entering the vertical expansion joint 130. In some embodiments, the corner seal may

also comprise an inorganic fibre blanket of the present disclosure. The flue wall 100 and headwall

110, which are in contact with the inorganic fibre based refractory mastic and blanket (when

present), are made from hot face refractory brick, which comprises an alumina content ranging from

at least 42 wt% alumina to at least 58 wt% alumina. A sealant system comprising inorganic fibres of

the present disclosure with a silica content of greater than 65.7 wt% is particularly beneficial in this

application due to the fibre's non-reactivity with alumina and the fibre's low shrinkage

characteristics at high temperatures.

An example of the furnace insulation system is illustrated in Figure 7, in which insulating lining

material 200 is attached to an inside surface of the furnace wall 210. The insulating material in use

having a hot face 220 which faces inwardly of the furnace; and a cold face 230 in contact with the

furnace wall 210, made of refractory bricks comprising alumina. The insulating lining material

comprise inorganic fibres in the form of blankets, folded blanket modules or high density (e.g. up to

Materials.

Other Potential uses

The fibres of the present disclosure can be used, subject to meeting relevant performance criteria, for any purpose for which fibrous inorganic materials, and particularly alkaline earth silicate and

aluminosilicate materials, have been used heretofore; and may be used in future applications where

the fibre properties are appropriate. The fibres and products derived therefrom of the present

disclosure may be used in applications which currently use commercially available products including,

but limited to SUPERWOOL* PLUS, SUPERWOOL*HT, SUPERWOOL* XTRA TM , THERMFRAX©, INSULFRAX 1300 HT, ISOFRAX© 1260, ISOFRAX® 1300, ISOFRAX© 1400, ISOFRAX© LTXTM, FINEFLEX

In the following reference is made to a number of patent documents relating to applications in which

the fibres may be used, subject to meeting relevant performance criteria for the application. The fibres

of the present disclosure can be used in place of the fibres specified in any of these applications subject

to meeting relevant performance criteria. For example, the fibres may be used as:

* bulk materials;

• deshotted materials [W02013/094113];

• in a mastic or mouldable composition [W02013/080455, W02013/080456] or as part of a wet

article [W02012/132271];

• as a constituent in needled or otherwise entangled [W2010/077360, W02011/084487]

assemblies of materials, for example in the form of blanket, folded blanket modules, or high

density fibre blocks [W02013/046052];

• as a constituent of non-needled assemblies of materials, for example felts, vacuum formed

shapes [W02012/132469], or papers [W02008/136875, W02011/040968, W02012/132329,

W02012/132327];

• as a constituent (with fillers and/or binders) of boards, blocks, and more complex shapes

[W02007/143067, W02012/049858, W02011/083695, W02011/083696];

• as strengthening constituents in composite materials such as, for example, fibre reinforced

cements, fibre reinforced plastics, and as a component of metal matrix composites;

• in support structures for fuel cells [W02020047036] or catalyst bodies in pollution control

devices such as automotive exhaust system catalytic converters and diesel particulate filters

[W02013/015083], including support structures comprising:

o edge protectants [W02010/024920, W02012/021270]; o microporous materials [W02009/032147, W02011019394, W02011/019396]; o organic binders and antioxidants [W02009/032191]; o intumescent material [W02009/032191]; o nanofibrillated fibres [W02012/021817]; o microspheres [W02011/084558]; o colloidal materials [W02006/004974, W02011/037617] o oriented fibre layers [W02011/084475]; o portions having different basis weight [W02011/019377]; o layers comprising different fibres [W02012065052]; o coated fibres [W02010122337]; o mats cut at specified angles [W02011067598];

[NB all of the above features may be used in applications other than support structures

for catalytic bodies]

• as a constituent of catalyst bodies [W02010/074711];

• as a constituent of friction materials [e.g. for automotive brakes [JP56-16578]];

• a component in insulation, fire protection or thermal runaway prevention materials in energy

storage devices [

* for fire protection [W02011/060421, W02011/060259, W02012/068427, W02012/148468,

W02012/148469, W02013074968];

• as insulation, for example;

o as insulation for ethylene crackers [W02009/126593], hydrogen reforming apparatus

[US4690690];

o as insulation in furnaces for the heat treatment of metals including iron and steel

[US4504957];

o as insulation in apparatus for ceramics manufacturing.

The fibres may also be used in combination with other materials. For example the fibres may be used

in combination with polycrystalline (sol-gel) fibres [W02012/065052] or with other biosoluble fibres

[W02011/037634].

Bodies comprising the fibres may also be used in combination with bodies formed of other materials.

For example, in insulation applications, a layer of material according to the present disclosure [for example a blanket or board] may be secured to a layer of insulation having a lower maximum

continuous use temperature [for example a blanket or board of alkaline earth silicate fibres]

[W02010/120380, W02011133778]. Securing of the layers together may be by any known mechanism, for example blanket anchors secured within the blankets [US4578918], or ceramic screws passing through the blankets [see for example DE3427918-A1].

Treatment of the fibres

In formation of the fibres or afterwards they may be treated by applying materials to the fibres. For

example:

* lubricants may be applied to the fibres to assist needling or other processing of the fibres;

• coatings may be applied to the fibres to act as binders;

• coatings may be applied to the fibres to provide a strengthening or other effect, for example

phosphates [W02007/005836] metal oxides [W02011159914] and colloidal materials such as

alumina, silica and zirconia [W02006/004974];

• binders may be applied to the fibres to bind the fibres subsequent to incorporation in a body

comprising such fibres.

Many variants, product forms, uses, and applications of the fibres of the present disclosure will be

apparent to the person skilled in the art and are intended to be encompassed by this disclosure.

By providing biosoluble fibres having maximum continuous use temperature higher than alkaline earth

silicate fibres, the present disclosure extends the range of applications for which biosoluble fibres may

be used. This reduces the present need, for many applications, to use fibres that are not biosoluble.

For the avoidance of doubt it should be noted that in the present specification the term "comprise"

in relation to a composition is taken to have the meaning of include, contain, or embrace, and to

permit other ingredients to be present. The terms "comprises" and "comprising" are to be

understood in like manner. It should also be noted that no claim is made to any composition in which

the sum of the components exceeds 100%.

Where a patent or other document is referred to herein, its content is incorporated herein by

reference to the extent permissible under national law.

It should be understood that usage of compositions of the names of oxides does not imply that these

materials are supplied as such, but refers to the composition of the final fibre expressing the relevant

elements as oxides. The materials concerned may be provided in whole or in part as mixed oxides,

compounded with fugitive components (e.g. supplied as carbonates) or as non-oxide components.

The term metal oxides and/or non-oxides is inclusive of all forms of metal including phosphates,

sulphates, halides or sulphides.

Claims

Claims

1. An insulation or sealant system comprising: a. a refractory component comprising a contact surface; and b. an insulating or sealant material comprising inorganic fibres having a composition comprising: 65.7 to 70.8 wt%SiO 2 ;

27.0 to 34.2 wt% CaO; 0.10 to 2.0 wt% MgO; and optional other components providing the balance up to 100 wt%, wherein the sumof SiO2 and CaO is greater than or equal to 97.8 wt%, wherein the other components, when present, comprises no more than 0.80 wt% A1 20 3 ; wherein the insulating

or sealant material is disposed against the contact surface, and wherein said refractory component comprises at least 20 wt% alumina.

2. The insulation or sealant system according any one of the preceding clauses, wherein the refractory component comprises at least 40 wt% alumina.

3. The insulation or sealant system according any one of the preceding clauses, wherein the amount of MgO and other components, when present, in the inorganic fibres are configured to inhibit the formation of surface crystallite grains upon heat treatment at 1100C for 24 hours, wherein said surface crystallite grains comprise an average crystallite size in a range of 0.0 to 0.90 pm.

4. The insulation or sealant system according to any one of the preceding clauses, wherein the sum of SiO2 and CaO is greater than or equal to 98.4 wt%.

5. The insulation or sealant system according any one of the preceding clauses, wherein the other components comprises a range of from 0.1 to 1.4 wt% of the sum of BaO + Cr 2 3 +

Fe 2 3 + HfO2 + La 2 3 +Mn 3 4 + Na 20+ K 20 + P 20 5 +SrO + SnO 2 + TiO 2 + V 205 + ZrO 2 + ZnO.

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Figure 1

Figure 2 (Prior art)

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Figure 3a

Figure 3b

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Figure 3c

Figure 3d

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Figure 4a

Figure 4b

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Figure 4c

Figure 4d

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Figure 5a

Figure 5b

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Figure 6

Figure 7