Crucibles Overview

All crucibles, alumina, magnesia and zirconia to name a few, are manufactured in Capital's own modern purpose-built facility in the Czech Republic where we press, cast and fire various materials into crucibles.

Product Range


Capital Refractories is able to supply a full range of isostatically pressed crucibles from 2 kg capacity to 75 kg, in different grades and qualities. We use a state-of-the-art semi-automated cold isostatic press. Cold isostatic pressing applies pressure to the workpiece in all directions producing products of uniform density. 

The advantages of Isostatically Pressed Crucibles are:

  • Wide range of qualities
  • Wide range of crucibles sizes
  • Smooth internal surface giving a reduction of inclusions
  • Consistent material properties throughout crucible
  • Defect free- no casting bubbles etc
  • Uniform density throughout the product improving its resistance to thermal stress


Crucibles are produced by vibration casting (vibrocast) when the required size or shape is uneconomical or impractical by the isopressing production method.

Capital Refractories can offer a range of vibration cast crucibles, including T-Pot Ladles:

Complex shapes, e.g. internal pouring siphon

To complement our range of crucibles we also offer numerous ancillary products and materials used within the investment and related foundry industries.


Quality Description Description
Alumina ..... General purpose crucible with good resistance to acidic and basic slags. Used for wide range of alloys and stainless steels
..... AL97I Superior erosion resistance
..... AL88I Improved thermal shock resistance
...... AL97C High resistance to slags.
..... 90C General purpose with excellent strength and thermal shock resistance.
..... 97C Good resistance to slags
..... 98C Very low silica - preferred for vacuum melting.


Quality Al₂O₃ SiO₂ MgO CaO Fe₂O₃
Alumina Al97I 97.5 1.6 - 0.1 <0.1
Alumina AL88I 88.5 9.4 0.1 0.1 0.2
Alumina AL90C 90.7 8.7 0.1 0.1 <0.1
Alumina Al97C 96.6 2.5 - 0.1 <0.1
Alumina AL98C 96.7 <0.1 - 2.1 <0.1


Quality Bulk Density (g / cm³) Apparent Porosity (%) Thermal Expansion (x10⁻⁶ / K) Thermal Conductivity (W / m K) Maximum Service Temperature (°C)
Alumina AL97I 2.95 23.8 8.0 4.2 1700
Alumina AL88I 2.95 23.8 8.0 4.2 1700
Alumina AL90C 2.91 18.0 7.7 4.0 1750
Alumina AL97C 3.10 19.6 8.0 4.6 1800
Alumina Al98C 3.23 16.0 8.0 4.5 1800

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