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Morgan's market-leading K™, JM®, and TJM® Insulating Firebricks (IFB) and SR™-90 and SR-99 High Alumina Firebricks are made for some of the most demanding and harshest environments.

Our IFBs and High Alumina Firebricks are manufactured to take the heat in demanding applications.

Features of Morgan's IFBs and High Alumina Firebricks

K, JM and TJM IFB

  • Low thermal conductivity
  • Low heat storage
  • High purity, high thermal shock resistance, consistent performance
  • Low iron and alkali flux content gives high refractoriness under load in operating conditions
  • High hot compressive strength
  • Tight dimensional tolerances
  • Large bricks or slabs and special shapes available
  • Purpose-designed packaging protects bricks in transit and facilitates on-site handling

Bubble Alumina IFB

  • High hot load deformation resistance
  • High hot compressive strength
  • Good corrosion resistance
  • High purity
  • High stability in complex chemical atmospheres at high temperatures
  • Tight dimensional tolerances
  • Large bricks and specialty shapes to reduce joints
  • Purpose-designed packaging protects bricks in transit and facilitates on-site handling

High Alumina Firebricks

  • 90% and 99% alumina firebrick
  • Excellent load-bearing strength at temperatures above 1650°C (3000°F)
  • Low SiO2 contents for use in hydrogen atmospheres
  • Very high service temperature 1800°C (3250°F)
  • Good corrosion resistance
  • High stability in complex chemical atmospheres at high temperatures
  • Tight dimensional tolerances
  • Excellent high-temperature stability

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Are you aware of the properties that determine thermal insulation value of IFBs?

Do you know the difference between Insulating Firebricks and Firebricks? After all, a brick is not just a brick.

Insulating Firebricks are low-density porous structure bricks capable of withstanding high temperatures. They are made in a range of grades, varying in maximum use temperature, insulating efficiency and density, the former affecting heat loss from the kiln and the latter affecting heat storage.

IFBs are specified in areas where a continuous operation above 1000°C (1832°F) is required, and corrosive gases are present.

Firebricks are commonly referred to as “dense” bricks. Our high alumina firebricks are very dense and have excellent load bearing strength at temperatures above 1650°C (3000°F) and provide excellent thermal shock resistance. The extremely low silica content of both products make them ideal for hydrogen atmospheres.

The thermal insulation capability of an Insulating Firebrick depends on the amount, sizing and distribution of air contained in the IFBs ceramic matrix.

In addition to providing good insulation at the required operating temperature, Insulating FirebBricks must remain thermally, chemically and dimensionally stable in the operating environment and sufficiently robust when ‘cold’
to be easily installed.

The chemical composition of an IFB gives to an expert eye an immediate idea of its temperature rating and its resistance against main compounds and environments, such as Hydrogen and Carbon Monoxide.

These properties are commonly used for defining and assessing the performance of Insulating Firebricks:

  • Density
  • Thermal conductivity
  • Thermal shock resistance
  • Porosity
  • Mechanical properties in cold state
  • Chemical composition
  • Dimensions
Density

The density of an Insulating Firebrick is one of the properties that, along with pore size, distribution and permeability, governs its insulating capability.

To measure the density, a sample fire brick is weighed and the middle of each face measured to calculate volume.

Density is calculated as mass divided by volume.

Thermal Conductivity

The thermal performance of an Insulating Fire Brick is specified by its thermal conductivity. Most applications require the brick to provide a specified heat loss and cold face temperature, without exceeding the temperature limitation of the brick.

Thermal conductivity can be measured using a standard test method such as that described in ASTM C182 (Standard Test Method for Thermal Conductivity of Insulating Firebrick) in which thermocouples and test samples are placed in a calorimeter to measure
the heat passing through a small sample wall in certain conditions.

  • Used between 200-1000°C (392-1832°F)
  • Precision ± 20%
  • Testing time 1 week

There are other systems used, such as the one known as “hot wire method” (ISO 8894-1), which measures the heat, generated by a wire, passing through the analysed material; however, these are less reliable and produce different data compared to ASTM standard.

  • Used between >1500°C (2732°F)
  • Precision ± 5%
  • Testing time 2 days
Thermal Shock Resistance

Based on ASTM C38 (Standard Test Method for Panel Spalling Testing Refractory Brick), this is a key property for Long Term Operation, especially in non-continuous operations (or part of the equipment), where steep temperature gradients are present.
This property will be important to define the lifetime of the brick.

The test consists of a number of cycles where, within a short time, the brick is brought near to its classification temperature and then cooled down with fresh air. The spalling loss in weight shall not exceed 1%.

Porosity

Apparent porosity (and implicitly bulk density) is related to thermal conductivity.

It is useful as a measure to compare products. Porosity is measured by weighing a sample before and after immersion in liquid
(usually water).

The difference, expressed as a percentage of the dry weight, is apparent porosity.

Mechanical properties in cold state

Modulus of Rupture (MoR) indicates the resistance to bending. The test is performed according to ASTM C-133 (Standard Test Method for Cold Crushing Strength and Modulus of Rupture of Refractories).

Typically:

  • 228 x 114 x 64 mm (9 x 41/2 x 21/2 inch) samples are machined in order to achieve tolerances and flattened or levelled out.
    Force is then applied in the mid-point of flat laid brick, according to standard rates and loads, until the sample breaks.
    The force at which the rupture took place, together with the pre-measured dimensions will allow us to calculate the MoR (MPa/psi).

Cold Crushing Strength (CCS) indicates the resistance to compression. It’s possible to measure CCS from the same sample
brick from the MoR. The sample is compressed until it breaks.

The load is then recorded and converted into CCS (MPa/psi), dividing the force by the area on which it was applied.

Mechanical properties in hot state

Hot strength:

The mechanical strength of an Insulating Fire Brick at its operating temperature is important to determine its suitability
for the application and to ensure the correct grade is selected.

Deformation under hot load:

Generally, high strength refractory bricks contain high glassy state which will soften at operating temperature, resulting in
relatively poor hot load strength.

This shows the temperature where a certain grade of plastic deformation occurs, under a constant load pressure, to a
refractory material; it is measured applying a constant pressure to a measured sample, raising the temperature until
the sample shows a certain deformation or collapses. Most commonly found are T0 and T0,5, expressing the highest
temperatures where respectively 0% and 0,5% deformation occurs.

Creep resistance:

The load-bearing strength or creep resistance is the ability of an IFB to maintain dimensional stability under load at
elevated temperature. This is determined by applying a constant pressure to a measured sample and holding at a given
high temperature for a certain time; the percentage change from original sample size expresses the subsidence value.
These are important factors in order to understand the stability of the wall when selecting the correct grade of material

Chemical composition

Chemical composition is a good indicator of the quality of an Insulating Firebrick.

It can be measured using a variety of methods, for example atomic absorption spectrometry or X-ray diffraction. No standard methods are specified.

The following key indicators are useful:

  • Al2O3 (Alumina) content is a good indicator of refractoriness; a high value means better resistance to temperature
    and many chemicals.
  • Fe2O3 (Iron oxide) content indicates purity; the lower its content (typically well below 1%) the more resistant the
    product will be to reducing atmospheres.
  • Na2O & K2O (Alkalis) content is also linked to purity; the lower the content of these low melting point compounds,
    the better the thermal stability of the product.
  • CaO (Lime) content is indication of a ceramic bonding system; a high content limits the maximum service
    temperature.
  • SiO2 (Silica) content describes the refractory matrix; a high silica content may indicate low working temperature
    rating.
  • CO2 (carbon dioxide) attack (according to ASTM C 288). The very low iron and alkali flux content (“purity”) gives good refractoriness and the high alumina content contributes to their stability in reducing atmospheres
    (CO2, H2 (hydrogen attack).
Dimensions - properties affecting them

Permanent Linear Change (PLC) is a measure of a refractory's permanent dimensional changes as a result of heating
to a specific temperature.

A specific specimen dimension is measured before and after heating at room temperature. PLC is calculated by the percentage change in these measurements.

Reversible Linear Change (RLC) is a measure of a refractory's dimensional changes as a result of heating cycle. A specific specimen dimension is measured before and after heating at room temperature.

The reversible linear change is then calculated by the percentage change in these measurements.