Pourables
By “pourable materials” we mean materials which flow by themselves after mixing, until they reach a level surface.
- Kerapour is a viscous insulation material which can be coaxed into highly inaccessible places.
- The Kerapump range is often installed by pouring. Kerapump 1 is a high strength, very fast setting material.
- Kerapump 2 is a very soft injectable material, mainly used in compensators, which can be poured.
- Kerapump 3 is a general purpose insulation material. It is also used in moulding, for its good machinability.
- Kerapump 6 is a dense andalusite pourable material.
- Kerapump 7 is a very user-friendly injectable insulation.
- Keratab Ultrafine is an alumina material used for very difficult castings, potting, and high temperature components.
- Electricast is a zircon based pourable material for intricate electrical components.
- Kerasic is a pourable silicon carbide material with extreme strength and abrasion resistance. Used for sintering trays, thermocouple sheaths, wire drawing sleeves and wear parts.
- Keratab Fine Special high strength tabular alumina pourable with good thermal shock resistance.
Electricast
Description: A fine, creamy, self levelling hydraulic bonded, rapid setting castable. It is largely composed of zircon, a zirconium silicate mineral with exceptionally high electrical resistivity. Its main application is the manufacture of electrical components and “potting” applications. After casting it is quite soft and very readily machinable. Normally it is prefired to 1200ºC, to give very high strength, but it can be used after firing to 400ºC. Strengths of up to 140 MPa have been recorded, using it in putty form with +6% water. Shrinkage on firing to 1200ºC is approximately 1% (With +9% water) Fired colour is buff to beige, unfired it is grey.
Maximum service temperature: 1300ºC.
Chemical analysis:
| Al2 O3 | 21% |
| Fe2 O3 | 0.1% |
| SiO2 | 27.6% |
| MgO | 0.1% |
| ZrO | 46.7% |
| CaO | 4.2% |
| Na2 O | 0.1% |
| K2 O | 0.01% |
| P2 O5 | 0.1% |
| Total | 100.1% |
Mixing: Add plus 9% water for pouring.
Applications: Element supports, leadouts, cup locks, candle components, bobbins, nozzles, cloning of electrical components.
Packaging: 25kg plastic bags.
Kerapour
Description: Kerapour is a cellular insulation material. It has an exceptionally high strength to density ratio and can be used as a structural member rather than just a filler. It has very low thermal conductivity due to its very fine structure. Kerapour has very low permeability due to its closed porosity. Kerapour is very easily mixed to a pourable consistency with +32% water, and flows right into the furthest corners, self-leveling.
| Temperature | C.C.S | Density | Porosity | P.L.C | Conductivity |
| 110oC | 11.2MPa | 1.1 | 50% | 0% | |
| 400oC | 11.9MPa | 1.02 | -0.38% | 0.28Wmk | |
| 800oC | 11.7MPa | 0.99 | -0.38% | 0.34Wmk | |
| 1000oC | 12.7Mpa | 1.06 | 61% | -0.90% | |
| 1300oC | 18.0Mpa | 1.07 | 58% | -3% |
Note: From the above data it is clear that Kerapour is exceptionally stable.
Particle size distribution: Very fine; 90% -0,85mm
Chemistry: Aluminosilicate.
Installation: Use 1.1tons per cubic metre. Mix with +32% water and pour it. Mixing can be done by hand in a bucket.
Applications: All insulation applications, especially where structural strength is an advantage, or installation is difficult or impermeability is desirable.
ISCOR pilot plant code: QJO
KERAPOUR DEMONSTRATION
1. FLOW
Mix 500g Kerapour with 160g water to give a highly viscous ball, which flows slowly but continuously, self-levelling. At this very viscous consistency the flow is most impressive. On a real installation, it can can be made wetter, to flow faster. After doing the demo. once, no need to weigh out the quantities.
2. THERMAL SHOCK RESISTANCE AND INSULATION
Take two crucibles. Put one upside down on a clearing at least 4m diameter, with no combustible materials nearby. Place the other crucible on top of it, upright. The lower crucible is to keep the demo. one away from splashes, which could burn you or make it difficult to pick up the crucible after the reaction. The splashes also heat the outside of the crucible if it is on the ground. If you only have one crucible, substitute a brick or something. Pour thermite powder into the crucible, about half full. Make a depression in the thermite powder and place in it either about a teaspoonful of ignition powder or push in a starlighter. Over this, place about half a teaspoon of fuse powder. Light the fuse powder with a match and move up-wind of it. The fuse powder gives off a lot of smoke, and lights the ignition powder/starlighter. The ignition powder generates intense heat and ignites the thermite powder. The thermite powder splashes sparks up to 1m away. It reaches a temperature of over 2000°C. Once the sparks have stopped for at least 6 seconds, pick up the crucible in your hands. The outside will still be cold, and remain so for at least half a minute. You can now pour out some molten steel, if there is a completely dry surface available. Give the crucible to the customer to hold.
The purpose of the demonstration is:
1. To impress the hell out of the customer.
2. To show that Kerapour can withstand a thermal shock of ambient to 2000°C in seconds without cracking.
3. To show how good cellular insulation is.
4. To prove that Kerapour can withstand super hot molten metal in a breakout situation.
Kerapour demo. crucibles are prefired to 400°C.
In the event of a burn from a spark, apply Bactrazine Flammazine ointment to the burn. (It has never happened yet in about 50 demonstrations.)
The demonstration is very impressive and frequently misleads the customer into considering Kerapour for high continuous temperature applications. Most of the applications which the customer now thinks of can be satisfied by Kerapour, Hollocast castable, Keratuff/Keratuff 2 plaster, or Kerapump 1 to 5.
Now that you have the customer’s attention and interest, you will find him very communicative.
Kerapump
Pumpable materials can be installed into inaccessible places, or can be mixed far from the site of installation and pumped, usually a high vertical distance to their point of application.
All very fine materials can be pumped, but only carefully designed ones keep their volume after drying, without shrinking. Pumpable materials are not necessarily self-flowing materials.
The most versatile pumping materials are self levelling, insensitive to water addition, do not segregate, and do not shrink. They may be strong or soft, dense or insulating.
The Kerapump range contains a variety of materials, mostly cellular insulation.
Kerapump 1 is a high strength, very fast setting material.
Kerapump 2 is a very soft injectable material, mainly used in compensators, which can be poured.
Kerapump 4 is a medium strength cellular insulation material.
Kerapump 5 is a very light precision casting material for components traditionally made from Marinite or calcium silicate.
Kerapump 6 is a dense andalusite pourable material.
Kerapump 10 is a very user-friendly injectable insulation.
Kerapump 10
Description: A pourable or pumpable insulation refractory. It is extremely fine and can be used for precision cast and detailed components. It can also be machined.
Maximum services temperature: 1150°C
CCS:
| 110°C | 7-12Mpa |
| 400°C | 10-15MPa |
| 1000°C | 6-10MPa |
| 1200°C | 15-25MPa |
Density: 1,15g/cm³
Thermal conductivity: About 0,4W/mK at 600°C
Chemistry: Aluminosilicate cellular insulation.
Water addition: + 40% by weight.
Applications:
Coke ovens pumping behind flashplates.
Blocking gas tracking.
Synthetic coals for gas fireplaces.
Chemical analysis:
| Al2O3 | 34% |
| Fe2 O3 | 1.0% |
| Cr2O3 | 0.04% |
| SiO2 | 37% |
| TiO2 | 1.5% |
| Ca2O3 | 16% |
| MgO | 0.5% |
| Na2O | 0.6% |
| K2O | 1.3% |
| MgO | 0.5% |
| P2O5 | 1% |
Packaging: 10kg plastic bags
Description: Kerasic is alumina bonded silicon carbide. The main problem with silicon carbide is that it oxidizes to silica. The alumina bond reacts with the silica to form a mineral called mullite, which has a needle like structure and imparts high strength, and has a melting point of 1850ºC. Kerasic is not as electrically conductive as other silicon carbide materials. Kerasic is a very fine grained material which can be poured like thick cream. Very detailed castings can be made with wall thicknesses down to 2mm. Plates have been made 300mm x 300mm x 5mm thick. The surface texture is very smooth, and the abrasion resistance of fired parts is excellent. The strength increases with repeated firing.
Cold crushing strength: 50 – 120 MPa
Chemical analysis:
| Al2 O3 | 34.0% |
| SiO2 | 2.0% |
| SiC | 58.0% |
| CaO | 6.0% |
Packaging: 25kg plastic bags.
Water addition for pouring: +12% vibration casting; +9%
Keratab Fine Special
Description: A self flowing self de-airing, fine tabular alumina pourable hydraulic setting ceramic.
Applications: Pipes, thin walled tubes, lead-outs, crucibles funnels, complex shapes, burner quarls.
Maximum service temperature: 1800°C
Maximum particle size: 0.5mm
Density: 2.85g/cm³
Air dry: 35MPa
Fired 1200°C: 80MPa
Mixing: Add +9% water, mix for 2 minutes and pour. Pot life 12 minutes.
Chemical analysis:
| Al2O3 | 97% |
| CaO | 3% |
| SiO2 | 0.01% |
| B2O3 | 0.008% |
| Fe2O3 | 0.01% |
| Na2O | 0.25% |
Keratab Ultrafine
Keratab is range of refractory materials mainly for electrical applications, where it is in contact with elements. Keratab can be supplied tailor made for the exact application, between an ultrafine creamy pourable material for delicate components and a coarse robust castable. A plasticized material, “Induction Coil Coating” is also part of the range. All formulations are essentially based on aluminium oxide and contain over 90% Al2 O3 . The iron content is less than 0.1% and sodium oxide less than 0.3%. The usual operating temperature is around 1300ºC to 1400ºC, but it could be used safely at 1700ºC. The colour is white and the texture is fine with a smooth surface.
Thermal shock resistance: A slab can be heated with an oxyacetylene flame until it melts locally, without the slab cracking.
Applications: Element holders, element holding bricks, kiln muffles, tubes, electrical connectors etc. For small production runs of intricate components, a sample can be cloned in Keratab by the Multimould system.
Test results on Keratab Ultrafine:
CCS:
| Dried | 40-60MPa |
| 400oC | 35-57MPa |
| 1050oC | 60-70MPa |
| 1200oC | 65-75MPa |
(At +16% water addition; creamy fluid)