Products — Electric power industry

Linings and insulation for boilers, CFB units and coal gasifiers

Fly-ash erosion in the cyclone, molten slag in the gasifier and acid condensate in the flue path each need a different material. This range covers the hot face, the back-up insulation and the fibre layer in one supply.

12: Power-industry product families
1800 °C: Maximum service temperature
100k t: Annual production capacity
1979: Making refractories since

Product catalogue

Grades & technical data

Shaped bricks

High chrome brick

Chromium oxide brick for coal gasifiers and slagging combustion chambers, where molten coal-ash slag attacks the hot face continuously. Available from 75 % to 95 % Cr2O3.

Model	RTSA-Cr-75	RTSA-Cr-85	RTSA-Cr-90	RTSA-Cr-95
Cr2O3 (%) ≥	75	85	90	95
Cr2O3 + Al2O3 + ZrO2 (%) ≥	98	98	98	98
SiO2 (%) ≥	0.2	0.2	0.2	0.2
Fe2O3 (%) ≤	0.3	0.3	0.3	0.3
K2O + Na2O (%) ≤	0.2	0.2	0.2	0.2
Bulk density (g/cm³) ≥	3.90	4.20	4.22	4.25
Apparent porosity (%) ≤	18	18	16	16
Compressive strength (MPa) ≥	120	120	120	120
Load softening temperature 0.2 MPa, 0.6 % (°C) ≥	1680	1680	1680	1680
Reheating linear change 1600 °C × 3 h (%)	±0.3	±0.3	±0.3	±0.3

Insulating products

High alumina heat insulation brick

Lightweight high-alumina back-up insulation for boiler walls, ducts and gasifier shells — six bulk densities from 1.2 to 0.5 g/cm³ to balance strength against heat loss.

Model	RTSA-1.2	RTSA-1.0	RTSA-0.8L	RTSA-0.7L	RTSA-0.6L	RTSA-0.5L
Al2O3 (%) ≥	48	48	48	48	48	48
Fe2O3 (%) ≤	2.0	2.0	2.0	2.0	2.0	2.0
Bulk density (g/cm³)	1.2	1.0	0.8	0.7	0.6	0.5
Compressive strength (MPa) ≥	4.5	4.0	3.0	2.5	2.0	1.5
Test temperature for ≤2 % permanent linear change (°C)	1400	1400	1400	1350	1350	1250
Thermal conductivity at 350 ± 25 °C (W/m·K)	0.55	0.50	0.35	0.30	0.25	0.20

Ceramic fibre

Ceramic fibre board

Rigid vacuum-formed fibre board for boiler doors, expansion joints and back-up insulation, classified from 1150 °C to 1400 °C.

Model	RTSA-TB-B1	RTSA-TB-B2	RTSA-TB-Z1	RTSA-TB-Z2	RTSA-TB-J	RTSA-TB-G	RTSA-TB-D
Classification temperature (°C)	1150	1260	1150	1260	1260	1260	1400
Recommended service temperature (°C)	900	1000	900	1000	1100	1100	1200
Bulk density (kg/m³)	220–260	300	220–260	300	320	420	300
Compressive strength at 10 % deformation (MPa) ≥	0.15	0.2	0.2	0.3	0.4	0.3	0.15
Bending strength (MPa) ≥	0.3	0.4	0.3	0.4	0.5	0.9	0.5
Permanent linear change, 24 h (%)	≤3 (900 °C)	≤3	≤3	≤3	≤3	≤3	≤3

Ceramic fibre

Ceramic fibre blanket

Needled fibre blanket in 64/96/128/160 kg/m³ densities for boiler casings, flue ducts and turbine exhaust insulation, classified up to 1430 °C.

Model	RTSA-TT-1	RTSA-TT-2	RTSA-TT-3	RTSA-TT-4	RTSA-TT-5	RTSA-TT-6	RTSA-TT-7
Classification temperature (°C)	1150	1260	1260	1400	1430	1430	1430
Recommended service temperature (°C)	900	1000	1100	1200	1350	1350	1250
Bulk density (kg/m³)	64/96/128/160	64/96/128/160	64/96/128/160	64/96/128/160	64/96/128/160	64/96/128/160	64/96/128/160
Tensile strength at 128 kg/m³ (kPa)	40	50	40	50	—	—	—
Permanent linear change, 24 h (%)	≤3 (900 °C)	≤3 (1000 °C)	≤3 (1100 °C)	≤3 (1200 °C)	≤3 (1350 °C)	≤3 (1350 °C)	≤3 (1250 °C)

Ceramic fibre

Ceramic fibre loose cotton (bulk fibre)

Bulk spun fibre for packing, mouldables and fibre-reinforced castables. Supplied in 20 kg or 80 kg bags.

Model	RTSA-TS-1	RTSA-TS-2	RTSA-TS-3	RTSA-TS-4	RTSA-TS-5	RTSA-TS-6	RTSA-TS-7
Classification temperature (°C)	1150	1260	1260	1400	1430	1430	1430
Recommended service temperature (°C)	900	1000	1100	1200	1350	1350	1250
Al2O3 (%)	/	≥44	45–47	≥53	≥35	≥43	≥47
SiO2 (%)	61–67	≥52	≥52	≥46	≥49	≥52	≥48
ZrO2 (%)	/	/	/	≥15	/	/	4–5
Cr2O3 (%)	/	/	/	/	2.0–3.8	/	/
CaO (%)	27–33	/	/	/	/	/	/
MgO (%)	2–7	/	/	/	/	/	/

Packaging: 20 kg or 80 kg bags.

Shaped bricks

Magnesia spinel brick

Spinel-bonded magnesia brick with good thermal shock resistance for high-temperature zones exposed to alkaline ash and cyclic operation.

Model	RTSA-TJ85	RTSA-TJ80
MgO (%) ≥	85	80
Al2O3 (%) ≥	3	3
SiO2 (%)	1.0	2.0
Apparent porosity (%)	16–17	16–17
Bulk density (g/cm³) ≥	2.95	2.95
Compressive strength at room temperature (MPa) ≥	45	55
0.2 MPa load softening point (°C)	1680	1650
Thermal shock stability (1100 °C water cooling, cycles)	7	8
Thermal conductivity at 1000 °C (W/m·K)	2.5	2.5

Shaped bricks

Chrome corundum brick

Corundum brick with 5–30 % Cr2O3 for gasifier and slag-tap zones — the chromia addition raises slag resistance while keeping corundum's strength and load behaviour.

Model	RTSA-CrC-5	RTSA-CrC-12	RTSA-CrC-20	RTSA-CrC-30A	RTSA-CrC-30B
Cr2O3 (%) ≥	5	12	20	30	30
Al2O3 + Cr2O3 (%) ≥	93	93	93	93	/
Cr2O3 + Al2O3 + ZrO2 (%) ≥	/	/	/	/	93
Fe2O3 (%) ≤	0.3	0.3	0.3	0.3	0.3
Bulk density (g/cm³) ≥	3.10	3.20	3.40	3.40	3.45
Apparent porosity (%) ≤	18	18	18	18	18
Compressive strength at room temperature (MPa) ≥	100	100	100	100	100
Load softening temperature 0.2 MPa, 0.6 % (°C) ≥	1700	1700	1700	1700	1700
Reheating linear change 1600 °C × 3 h (%)	±0.3	±0.3	±0.3	±0.3	±0.3

Shaped bricks

Zirconium mullite brick

ZrO2-reinforced mullite brick with a very low wear coefficient — used where fly-ash abrasion and thermal cycling occur together.

Model	RTSA-GM6
Al2O3 (%) ≥	78
Fe2O3 (%) ≤	1.5
ZrO2 (%)	6
Apparent porosity (%) ≤	18
Compressive strength at room temperature (MPa) ≥	100
Bulk density (g/cm³)	2.7
0.2 MPa load softening point (°C)	1680
Thermal shock stability (1100 °C water cooling, cycles) ≥	15
Wear resistance coefficient (cc) ≤	4

Insulating products

Lightweight mullite brick

Low iron, low thermal-mass mullite insulating brick classified from 1100 °C to 1650 °C — hot-face insulation for boilers, reformers and gasifier outlets.

Model	RTSA-JM-23A	RTSA-JM-23	RTSA-JM-26A	RTSA-JM-26	RTSA-JM-28	RTSA-JM-30
Classification temperature (°C)	1100	1260	1350	1430	1540	1650
Bulk density (kg/m³)	500	600	800	800	900	1050
Bending strength (MPa)	0.7	0.8	1.2	1.5	1.8	2.0
Cold compressive strength (MPa)	0.8	1.0	1.8	2.0	2.5	3.0
Permanent linear change, 24 h (%)	-0.5 (1070 °C)	-0.2 (1230 °C)	-0.5 (1350 °C)	—	—	—

Shaped bricks

Silicon carbide brick

High thermal-conductivity SiC brick from 40 % to 90 % SiC for CFB boiler cyclones, air distributors and ash hoppers, where erosion is the dominant wear mechanism.

Model	RTSA-S-90	RTSA-S-80	RTSA-S-70	RTSA-S-60	RTSA-S-40
Long-term service temperature (°C)	1450	1450	1450	1400	1350
SiC (%)	90	80	70	60	40
Al2O3 (%)	/	/	/	/	42
Bulk density (g/cm³) ≥	2.65	2.65	2.60	2.60	2.50
Apparent porosity (%) ≤	15	16	16	18	18
Compressive strength at room temperature (MPa) ≥	120	100	80	60	60
Reheating linear change 1450 °C × 3 h (%) ≤	0.3	0.5	0.5	0.5 (1400 °C)	0.6 (1400 °C)
Thermal shock stability (1100 °C air cooling, cycles)	30	25	25	20	20
Thermal conductivity at 800 °C (W/m·K)	10–12	8–10	6–8	—	—

Shaped bricks

Acid resistant brick

Dense vitrified brick for chimneys, flue-gas desulphurisation ducts and acid condensate zones — acid resistance of 99.7 % and above.

Model	RTSA-NS-1	RTSA-NS-2	RTSA-NS-3	RTSA-NS-4
Water absorption A (%)	0.2 ≤ A ≤ 0.5	0.5 ≤ A ≤ 2	2 ≤ A ≤ 4	4 ≤ A ≤ 5
Flexural strength (MPa) ≥	58.8	39.2	29.4	19.6
Acid resistance (%) ≥	99.8	99.8	99.8	99.7
Thermal shock stability (ΔT)	100 °C	130 °C	100 °C	150 °C

After one thermal shock test the sample must show no cracking, peeling or other damage.

Insulating products

Alumina hollow ball brick

Hollow-sphere alumina brick combining a 1800 °C service capability with low thermal conductivity — hot-face insulation for high-temperature power and gasification equipment.

Model	RTSA-KQ-98	RTSA-KQ-88
Long-term service temperature (°C)	1800	1650
Al2O3 (%) ≥	98	88
SiO2 (%) ≥	0.3	/
Fe2O3 (%) ≤	0.2	0.5
Bulk density (g/cm³)	1.40–1.80	1.35–1.80
Compressive strength at room temperature (MPa) ≥	10	8
Load softening temperature 0.2 MPa, 0.6 % (°C) ≥	1700	1650
Reheating linear change 1600 °C × 3 h (%)	±0.3	±0.3
Thermal conductivity at 800 °C (W/m·K)	1.0	0.9
Linear expansion coefficient at 1300 °C (1/°C)	8 × 10⁻⁶	8 × 10⁻⁶

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