Specialty
Gunning Spray Cement Application & Supply
Gunning spray cement (gunning mix, refractory shotcrete) is a pneumatically-applied refractory material used to repair, reline or build up worn refractory surfaces — without dismantling the existing structure. It is the fastest and most cost-effective method for boiler furnace walls, cyclone preheaters, kiln burners and any geometry where casting is impractical.
When gunning is the right choice
Gunning spray cement is preferred over casting in three scenarios: (1) repair of localised wear during a planned shutdown when full demolition is not justified, (2) lining of complex geometries — boiler furnace walls with tube banks, cyclone separators, ducts — where formwork would be impossible, and (3) emergency relining when shutdown duration is critical. Properly executed gunning achieves 92–96% of cast-density and matches casting performance in most boiler and power-plant applications.
- ▸Boiler furnace wall relining (CFBC, AFBC, pulverised-coal)
- ▸Cyclone separator hot zones
- ▸Cement kiln burner & hood gunning
- ▸Repair of cracked or eroded castable linings
- ▸Emergency / shutdown-window relining
Materials we supply and apply
We stock and apply all major gunning mix grades from leading Indian manufacturers — selected per the operating temperature, atmosphere and abrasion conditions of your equipment.
- ▸High-alumina gunning mix (60–90% Al₂O₃) for high-temperature service
- ▸Basic / magnesite gunning for steel ladles and converters
- ▸Insulating gunning mix for backup layers and ducts
- ▸Wet-gunning material for low-rebound applications
- ▸Specialist abrasion-resistant gunning for cyclone hot zones
Our gunning equipment & operators
We deploy rotor-type and dual-chamber gunning machines with experienced operators. Operator skill is the single biggest factor in gunning quality — rebound rate, density and lining thickness all depend on nozzle technique. Our supervisors have 10+ years on cement-kiln calciners, CFBC boiler furnace walls and cyclone preheater hot zones.
Frequently asked questions
What is the difference between gunning and shotcreting?▼
Both refer to pneumatic application of refractory through a nozzle. "Gunning" is the dry-process variant — refractory powder is conveyed dry and water is added at the nozzle. "Shotcrete" or "wet-gunning" pre-mixes water before pumping. Dry gunning has lower equipment cost and is preferred for refractory work. Wet shotcrete has lower rebound (less waste) and is used where dust must be minimised.
How much rebound (waste) should I expect?▼
With trained operators on dry gunning, rebound is typically 15–25% of input material. Wet gunning brings rebound below 10% but at higher equipment cost. We always quote with rebound included so your budget is realistic.
Can gunning be done while equipment is hot?▼
Yes — hot gunning during operational windows is possible for short repairs (e.g. cyclone hot-zone touch-up). However, full-thickness relining requires the equipment to cool to under 100°C for proper bond development. We assess case-by-case during the pre-shutdown survey.
What is the typical curing schedule for gunning?▼
Gunning mix typically cures with a 24-hour air dry followed by controlled heat-up at 25–35°C/hour up to first hold-point (~150°C), then ramp to 350°C, hold, ramp to operating temperature. Exact schedule depends on the manufacturer's TDS — we follow it strictly and document temperature logs for your audit file.
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