Castables

Keramicalia does not manufacture standard castables, since there are a large number of companies already making them. We do make a few special castables.

  • Technicast: A very high density zircon-andalusite material for extreme environments.
  • Pipe mix: A low cement andalusite castable for high integrity. Developed for the DRH process.
  • Keracast: A totally lime free.
  • Keraflow 1900: A self-levelling tabular alumina castable for precasting.
  • Rubycast: Used in gold smelting pots.
  • Hollocast: A range of cellular insulation castables.
  • Keralite: A range of cellular insulation castable to replace IFB’s.
  • Hardcast: A range of silicate bonded materials for various purposes, including castable for hot floors, acid resistance and shallow repairs.
  • Keratab dump mix: A self-flowing alumina for installation in difficult areas without vibration.
  • Kerabrade C: A very string abrasive resistant castable.
  • Keratab: A range of tabular alumina castables.
  • Insulmag: A basic insulation castable.
  • Coke wharf mix: A high density castable for high heat retention.
  • Keraclase: A periclase (MgO) castable, high purity magnesia castable for electric arc furnaces.
  • Keralcast: A very resistant castable for contact with molten aluminium.

See Pourables for self-flowing silicon carbide, zircon and tabular alumina material.

Coke wharf mix

This is a high density thermal shock resistant mix.

It was developed for lining coke wharves, where tons of burning coke is pushed onto a sloping floor before quenching in water.

It can withstand repeated heating to 1000°C and quenching in water. It is acid resistant and abrasion resistant.

The high density results in high thermal mass, and the material has found a number of applications for heat storage and others for heat dissipation.

Maximum service temperature: 1100°C.

Maximum particle size: 15mm. Also available in 6mm.

Water addition: +9%

Packaging: 25kg plastic bags, and 15kg plastic bags for 6mm.

Insulmag

Insulmag is a basic refractory insulation material.

Insulmag consists of magchrome and Hollofill aggregate, hydraulic bonded. It has a low density of 1.3g/cm³ and a high strength to density ratio.

If has a fine structure and even texture, giving good thermal shock resistance.

It is easily installed, being highly fluid and insensitive to temperature, contamination, and water quality. It mixes easily and can be poured into place.

Water addition is +30% by weight: 3 litres per bag.

Chemical analysis:

Al2 O3 28.0%
Fe2 O3 8.0%
Cr2 O3 12.0%
SiO2 8.0%
TiO2 0.2%
CaO 9.0%
MgO 33.0%
Na2 O 0.2%
K2 O 0.3%
P2 O5 0.2%

 

Packaging: 10kg plastic bags.

Kerabrade C

Description: An abrasion resistant high strength castable for use up to 1200°C. The matrix is very hard, and fracture will occur right through the aggregate grains.

Physical properties:

Bulk density: 2.25g/cm³
Cold crushing strength: 100 to 150MPa
Permanent linear change: -0.2% after 800°C
Thermal conductivity: 1.6W/mK

Chemical analysis:

Al2O3 46.0%
FE2O3 0.9%
SiO2 49.0%

 

Installation: Place +7.5% water in a planetary (bakery type) mixer. Add half of the powder and mix until fluid. Add another quarter of the powder and mix until fluid. Slowly add the last quarter of powder, keeping the mix fluid. This will take about 5 minutes. The result is a self-levelling fluid.

Packing: 25kg plastic bags

Keracast 3

Description: A cement free castable. It contains over 95% aluminosilicates and hardly any fluxes. Strength increases with temperature, but good thermal shock resistance is retained.

Maximum service temperature: Proven up to 1500ºC, probably in excess of 1600ºC.

Chemical analysis:

Al2 O3 40.9%
Fe2 O3 1.1%
SiO2 54.4%
TiO2 1.61%
CaO 0.37%
MgO 0.58%
Na2 O 0.05%
K2 O 0.44%
P2 O5 0.0%
L.O.I. 0.9%
Total 100.35%

 

Installation: Add plus 1-.5% Keracast binder to the powder, mix rapidly and vibration cast without delay.

Pilot Plant Code: MPS.

Keracast 6

Keracast 6 is a totally cement free, CaO free material. It is consequently highly refractory. The chemical analysis is approximately as follows:

Al2 O 90.0%
Fe2 O 0.14%
SiO2 9.0%
TiO2 0.12%
CaO 0.03%
MgO 0.22%
K2 O 0.04%
Na2 O 0.2%

 

The mineral composition is about 87% alpha alumina, which is synthetic corundum, with a melting point of 2013ºC and 13% mullite, Al2O3 .SiO2 , with a melting point of 1850ºC. The material therefore contains very little liquid phase below 1850ºC. Both mullite and corundum are chemically inert and immune to attack by sulphurous or acid gases. To develop good strength we pre-fire the castings to 1200ºC, so that the silica is all present in the mineral mullite. Mullite grows in needle-like crystals, which enhance the strength of the composite. Corundum is the second hardest natural mineral, with a hardness of 9 on the Moh scale. (Diamond is the hardest, at 10 on the scale.) The only refractory materials with higher melting points are lime, magnesia and zirconia. All three are prone to thermal shock.

Formulation no. 11484

Keraflow 1900

Description: Keraflow 1900 is probably the highest temperature Tabular alumina castable developed to date. It contains no silica. Conventional castables containing tabular alumina are also silica free, but need high water contents. Keraflow 1900 can be a vibration cast at only +3.8% water, and FLOWS SELF-LEVELLING AT +4,5% WATER. Consequently the strength is exceptionally high. Mix intensively for at least 4 minutes.

Chemical analysis:

Al2 O3 97.8%
Fe2 O3 0.1%
SiO2 0.1%
TiO2 0.1%
CaO 1.5%
MgO 0.1%
Na2 O 0.2%
K2 O 0.1%
P2 O5 0.1%

 

Physical properties: (5 hours soak)

Density g/cm³ CCS MPa P.L.C. % Hot MoR MPa Porosity
Air dry 3.2 20 to 30 0
110ºC 3.2 40 to 100 0 12%
800ºC 3.16 50 to 120 0
1000ºC 3.14 40 to 70 -0.02
1500ºC 3.13 100 to 250 -0.03 16 16%
1650ºC 3.20 120 to 280 -0.44 14%

The variation in strength is due to different water contents.

Applications: Just about any application where the temperature is extremely high or the chemical or physical environment is too severe for normal materials.

Packaging: 25kg clear polyethylene bags.

Keratab

Keratab is range of refractory materials 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 holding brick, kiln muffles, tubes, electrical connectors etc…

For small production runs of intricate components, a sample can be cloned in keratua by the multimould system.

Keratab dump mix

Description: A dump mix is a self-levelling castable for discharge directly into the installation. It flows rapidly without any assistance and de-airs itself. It is based on tabular alumina. It can handle severe thermal shock.

Chemical analysis:

Al2 O3 90.0%
Fe2 O3 0.2%
SiO2 0.2%
CaO 9.6%

 

Cold crushing strength:

C.C.S. MPa Density g/cm³
Air dried 40g/cm³ 2.78
110ºC 38g/cm³ 2.74
400ºC 94g/cm³ 2.64
1200ºC 54g/cm³ 2.50

 

Mixing: Mix with +9% water. It flows for about 20 minutes. It should be discharged directly into the mould, since its flow properties do not allow handling in buckets or wheelbarrows. No vibration is needed. Heat of hydration is high but delayed. Drying should be slow and careful, as the material has very low permeability and a very fine pore size distribution (About 7 hours).

Packaging: 25kg plastic bags.

Shelf life: 12 months in unpunctured bags.

Test results are based on single cubes.

Pipe mix

Description: A high density, very low permeability aluminosilicate castable. It has excellent electrical insulation properties. Easy to cast, good flow, excellent microstructure.

Maximum service temperature: 1750ºC

Bulk density: 2.65g/cm³

Cold crushing strength: 75MPa.

Thermal conductivity: 1.2W/mK

Chemical analysis:

Al2 O3 61.0%
Fe2 O3 0.6%
SiO2 36.0%
TiO2 0.16%
CaO 2.0%
MgO 0.1%
Na2 O 0.05%

 

Installation: Add plus 5.5% Water and vibration cast. If more water is added, the setting time will be long.

Packaging: 25kg plastic bags.

Rubyflow

Description: Rubycast is a very strong, highly refractory castable for extreme service environments. It flows well during vibration casting and has excellent thermal shock resistance and abrasion resistance.

Maximum service temperature: 1750°C.

Chemical analysis:

Al2 O3 70.0%
Fe2 O3 0.6%
Cr2 O3 2.3%*
SiO2 25.0%
TiO2 0.2%
CaO 2.0%
K2 O 0.25%

* The chrome oxide is continued in the chrome-alumina aggregate, and not as a green chromic oxide addition.

Density: 2.6 to 2.65 (2.65 tons per cubic meter)

Water addition: 5.5 to 6.8 litres per 100kg.

Cold crushing strength:

Dry 80Mpa, 1000°C 90Mpa.

P.L.C. -.18% fired at 1000°C.

Thermal conductivity: 1.5W/mK at 1000°C.

Packaging: 25kg transparent polythene bags.

Keraclase

A periclase (magnesia, MgO) refractory of high purity and refractoriness.

Composition:

95% MgO
<2.5% SiO2
<1% Al2 O3
<2% Fe2 O3
<1% K2
<2% Na2 O

 

Bulk density: 2.75 to 2.85g/cm3

Thermal conductivity: Around 4.0W/mK

Cold crushing strength: 45 MPa plus

Max particle size: 6mm

Max service temperature, continuous: 1800C

Water addition: Nil for dry spiking, +3-5% for ramming, +6-8% for casting, use vibration.

Setting: Note that it takes days to set.

Curing: After 2 days the former may be removed and heating may start immediately. Do not leave Keraclase casting wet for too long in a hot damp climate, it will hydrate and crack.

Packaging: 25kg plastic bags.

Development no. 115300

Technicast

Description: A very high density zirconia-alumina-silicate castable with good workability and high strength. Very user friendly. Lantz was here.

Chemical analysis:

Al2O3 40.9%
Fe2O3 1.1%
SiO2 54.4%
TiO2 1.61%
ZrO 25.0%
CaO 0.37%
MgO 0.58%
Na2O 0.05%
K2 O 0.44%
P2 O 0.0%
L.O.I. 0.90%
Total 100.35%

 

Physical properties:

Density CCS PLC
air dry 3.12g/cm³ 55
400ºC 3.01g/cm³ 76
1000ºC 2.92g/cm³ 79
1200ºC 2.92g/cm³ 34

 

Installation: Add plus 3.8% water

Applications: Difficult castings and precast.

Packaging: 25kg plastic bags on 1 ton pallets stretchwrapped.

Pilot Plant code: MPS

Development no. 36112

Hollocast

Hollocast is the castable group of cellular insulation materials. They are strong insulation materials with largely sealed porosity.

Hollocast 1 is the general purpose castable, which is very user-friendly. It has an excellent track record in a very wide variety of applications.

Hollocast 2 is a low cement variety designed for pre-fired components, giving lower creep in load bearing kiln furniture.

Hollocast 3 contains barium, for aluminium furnaces.

Hollocast 4 is based on bubble alumina and Hollofill.

Hollocast 5 is based on bubble alumina and is totally silica free.

Hollocast 6 is based on a calcium aluminate foam with a composition of which is highly refractory. It is the best insulation material for 1500°C.

No.

Density

Maximum service temp

Price / Kg 2016

Silica Content

Water Addition

Development No.

1

1.5

1400°C

R28.00

41.3

+20%

55597

2

1.5

1350°C

R28.00

±43%

+17%

32904

3

1.7

1500°C

R28.00

±38

+14%

108501

4

1.2

1500°C

R50.00

7.2%

+16%

40330

5

2.1

1700°C

R71.00

±0.1%

+8%

40329

6

1.1

1500°C

R126.00

±0.05%

+60%

41645

Keralite

Keralite is a range of cellular insulation materials used mainly for precasting, to replace insulating firebricks.

Keralite 1: For high strength, fine finish and intricate castings. Also used for modelling, for its good machinability. Density 1.1 Water addition +35% castable with or without vibration. Used at up to 1250°C. Supplied in 15kg bags.

Keralite 2: General purpose replacement of IFB’s, because it has higher strength and can be moulded to required shape with no cutting or wastage. Has a density of 0.75. Add +45 to +50% water. They can be used at up to 1220°C. Supplied in 10kg bags.

Keralite 3: Differs from normal cellular insulation in that the matrix is hollow. It is not supplied in castable form, only precast parts. Used mainly for its high permeability, even structure and great machinability.

Keralite 4: Has a density of 0.5 and a maximum service temperature of 1230°C. It contains polystyrene balls which give off fumes during initial firing, which irritate ones eyes. Use with +40% water. Supplied in 10kg bags.

Keralite 5: A higher temperature material, mainly used in direct gas flame impingement areas. Has a density of 0.95. Develops high strength at 1200°C. Contains fine expanded polystyrene balls. Add plus 34% water. Supplied in 15kg bags.

Hardcast

Hardcast is a range of silicate bonded materials.

It is used in place of concrete where very low permeability is necessary, for acid resistance.

It is also very quick setting, and can be used in thin applications where concrete would be sucked dry before it can set, for example repairs of factory floors.

It can be used to repair acid damaged floors: Hardcast Acid Resistant Floor Screed.

Hardcast light is an acid resistant insulation.

Chloresist is the high temperature version, used in incinerators where chloride attack is the main problem.

Hardcast Fine Acid Resistant Mortar is used as a glue where air setting is not possible, for example when bonding impervious sintered ceramic tubes.

The data sheets are all very similar, just read one and you know all the tricks. Once you have started using Hardcast, you will seldom use concrete again for small jobs.

Rubycast

Description: Rubycast is a very strong, highly refractory castable for extreme services environments. It flows during vibration casting and has excellent thermal shock resistance and abrasion resistance.

Maximum Services temperature: 1750°C

Chemical analysis:

Al2O3 70%
Fe2O3 0.6%
Cr2O3 2.3%
SiO3 25%
TiO2 0.2%
CaO 2%
K2O 0.25%

*The chrome oxide is contained in the chrome the chrome-alumina aggregate, and not as a green chromic oxide addition.

Density: 2.6 to 2.65 (2.65 tons per cubic metre).

Water addition: 5.5 to 6.8 litres per 100kg.

Cold crushing strength: dry 80MPa 1000°C 90MPa.

Permanent Linear change: 0.18% fired 1000°C.

Thermal conductivity: 1.5W/mK@1000°C.

Packaging: 25kg transparent polythene bags.

Keralcast

Description: Alumina based abrasion resistant castable.

This is new technology, previous high abrasion resistant ceramics are based on high additions of silica fume. Keralcast has only 1% silica and can therefore be used at high temperatures, up to 1750C with virtually no molten phase present.

Density: 3.06 g/cm3

Max particle size: 5mm

Thermal conductivity: 2W/mK

Water addition: Extremely low, +4.5%

Mixing: 7 minutes in a bakery mixer or 20 minutes in a pan mixer. The consistency can be adjusted from putty to self-flowing, as preferred.  The setting time can be adjusted from half an hour to 6 hours, as preferred.

Testing: Try to grind it on a bench grinder.

Shelf life: 2 years.

Packaging: 25 kg plastic bags.

Project no. 1142

Claimer: This data sheet had better be correct because Dave Onderstall stakes his reputation on it.

Keracast 1200

Description: Keracast 1200 is a refractory castable for moderate temperatures with high strength and resistance to thermal cycling.

Composition: Calcium aluminate bonded high thermal mass aggregate.  

Physical properties:

Maximum particle size: 6 mm
C.C.S: 40 MPa
Bulk density: 2.52 g/cm3
Total porosity: ± 13%
Permanent linear change: +0.94% measure after firing at 1100°C
Thermal conductivity: 200°C ± 1.0 W/mK
  400°C ± 1.0 W/mK
  600°C ± 1.1 W/mK
  800°C ± 1.2 W/mK

 

Applications: General purpose use from 250°C to 1200°C.

Installation: Mix with +9% water and place by vibration.

Packaging: 20kg plastic bags. Stretch wrapped on pallets of 1 ton.

Shelf life: About 18 months

Development no. 179700

Claimer: The above information had better be correct as Dave Onderstall stakes his reputation on it.