Construction method and characteristics of refractory gunning castable

August 15, 2018
The construction methods of refractory gunning castable include wet spray, semi-dry spray, and flame spray.
Wet spray is a method in which refractory aggregates, binders, additives and water are mixed to form a certain consistency of mud, and then the slurry is sprayed onto the spray surface by compressed air using a spray machine. It is characterized by simple operation, high adhesion rate and rapid sintering. However, due to the large water content and finer grain, the shrinkage is also large. At the same time, because the spray layer is thinner, the durability is not so good.
Semi-dry spray is a method in which a mixture of refractory aggregates, binders, additives, etc., is mixed with water through a water ring hole of the spray gun end, and is sprayed by compressed air onto the spray surface, and the amount of water is used. It can be adjusted at any time according to the situation of spraying, generally fluctuating between 10 and 20%, which is much lower than the water consumption of wet spraying. Therefore, the spray layer has a large bulk density and a small shrinkage, and a thicker spray layer can be obtained, and the durability is good, but the rebound amount is slightly higher than the wet method, and the spray method is relatively common.
Flame spray is to use compressed oxygen to transport the mixture of refractory aggregate, flux or heat generating agent to the nozzle, and mix and burn with high calorific value fuel to instantly heat the surface of the refractory aggregate particles to a molten or semi-molten state, and then spray the stick. The repairing method attached to the furnace lining, the spray-repairing layer obtained by the construction method has the advantages of compact structure, high strength, strong anti-erosion and anti-scouring ability, and is firm and durable. However, the flame spray device has high cost, complicated technology and high energy consumption for construction.