What are the different ways of fire-resistant gunning material?

1 Wet gunning is a method in which refractory aggregates, binders, additives and water are mixed to form a slurry with a certain consistency. The magnesia carbon bricks are then sprayed onto the gunning surface with compressed air through a gunning machine. Its characteristics are simple operation, high adhesion rate and rapid sintering. However, due to the large water content and finer grain size, the shrinkage is also greater. At the same time, because the gunning layer is thinner, the durability is not very good.

2 Semi-dry gunning is a method in which refractory aggregates, binders, additives, etc. are mixed with water through the water ring holes at the spray gun and sprayed onto the gunning surface by compressed air. The dosage can be adjusted at any time according to the spraying situation, and generally fluctuates between 10-20%, which is much lower than that of wet spraying. Therefore, the gunning layer has a large volume density, less shrinkage, and a thicker gunning layer can be obtained. It has better durability, but the rebound amount is slightly higher than that of the wet method. This gunning method is more common.

3 Flame gunning is to use compressed oxygen to transport the mixture of refractory aggregate, flux or heating agent to the nozzle, mix and burn with high calorific value fuel, instantly heat the surface of refractory aggregate particles to a molten or semi-molten state, and then spray The repair method adhered to the furnace lining. The gunning layer obtained by this construction method has a compact structure, high strength, strong erosion resistance, erosion resistance, and durability. But the flame gunning device is expensive, the technology is complicated, and the construction consumes a lot of energy.