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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.
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:
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:
Benefits
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 |
| Alumina: | General purpose crucible with good resistance to acidic and basic slags. Used for a wide range of alloys and stainless steels. |
| .....AL97I | .....Superior erosion resistance |
| .....AL88I | .....Improved thermal shock resistance |
| .....AL90C | .....General purpose with good strength and thermal shock resistance. |
| .....AL97C | .....Improved resistance to slag. |
| Chrome Alumina | High resistance to slags; preferred to alumina in more arduous applications. |
| .....CA93I | .....Superior erosion resistance |
| .....CA84I | .....Improved thermal shock resistance |
| .....CA91I | .....Superior thermal shock resistance |
| Magnesia | High resistance to basic slags. |
| .....MG88I | .....Used for a variety of alloys. |
| .....MG95I | .....Higher resitance to more exotic alloys. |
| Quality | Al₂O₃ | SiO₂ | MgO | CaO | Fe₂O₃ | Cr₂O₃ | ZrO₂ + HfO₂ |
| Alumina AL91I | 97.5 | 1.6 | - | 0.1 | <0.1 | - | - |
| Alumina AL88I | 88.5 | 9.4 | - | 0.1 | 0.2 | - | - |
| Alumina AL90C | 90.7 | 8.7 | <0.1 | 0.1 | 0.1 | 0.2 | - |
| Alumina AL97C | 96.6 | 2.5 | <0.1 | 0.1 | 0.1 | 0.2 | - |
| Chrome Alumina CA93I | 93.4 | 2.2 | - | 0.1 | <0.1 | 3.6 | - |
| Chrome Alumina CA84I | 84.3 | 9.0 | - | 0.1 | 0.2 | 4.8 | - |
| Chrome Alumina CA91 | 91.5 | 2.2 | - | 0.1 | <0.1 | 5.3 | - |
| Magnesia MG88I | 3.5 | 3.8 | 88.0 | 3.8 | 0.2 | - | - |
| Magnesia MG95I | 0.5 | 0.8 | 95.0 | 2.5 | 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 | 2.59 | 23.8 | 8.0 | 4.2 | 1700 |
| Alumina AL90C | 2.9 | 18.0 | 7.7 | 4.0 | 1750 |
| Alumina AL97C | 3.1 | 19.6 | 8.0 | 4.1 | 1800 |
| Chrome Alumina CA93I | 3.05 | 23.0 | 8.2 | 3.4 | 1800 |
| Chrome Alumina CA84I | 2.85 | 20.0 | 7.6 | 3.4 | 1730 |
| Chrome Alumina CA91I | 3.10 | 21.5 | 8.2 | 3.4 | 1800 |
| Magnesia MG88I | 2.83 | 17.0 | 14.5 | 2.4 | 1700 |
| Magnesia MG95I | 2.95 | 15.0 | 13.0 | 2.5 | 1750 |
Crucibles suffixed I are isopressed, those sufficed C are cast.
