Fire resistant spraying coating is a kind of refractory material constructed by spraying refractory mixture onto the kiln lining with a spray gun, which is composed of refractory aggregate, powder and binder. Spray coating is generally amorphous refractory with small particle size, and common spray coatings include low-temperature curing spray coating, high-strength wear-resistant spray coating and clay fire-resistant spray coating.
characteristic
1. Good integrity can be achieved without sintering in non high temperature environment.
2. The construction is convenient and can be sprayed and applied.
3. Suitable for a variety of temperature environments, easy to bond and low rebound rate.
4. Good overall performance, erosion resistance.
5. It has good volume stability and air tightness.
purpose
It is used for kiln lining that is not easy to build and pour, such as lining of high-temperature kilns or pipes such as blast furnace, hot blast furnace and sintering machine. Light spray coating is generally used for thermal insulation layer, and heavy spray coating can be used for thermal insulation layer and working layer lining.
What are the spraying process methods
1. Wet spraying wet spraying refers to spraying water or liquid binder onto the sprayed surface through a spray gun.
2. Dry spraying dry spraying refers to the direct spraying of the mixed fire-resistant coating onto the sprayed surface through the nozzle, which is mainly used to repair the kiln.
3. Flame spraying flame spraying is to use oxygen to transport the mixed fire-resistant coating to the nozzle and spray it together with the combustible gas. The combustible gas burns, and the materials move in the flame and melt into a plastic state and shoot on the sprayed surface. This method is mainly used for hot gunning furnace lining.
Spraying construction
1. Construction of anchor nails for spraying: Y-type and T-type metal anchor nails of different specifications are set on the sprayed lining, which are arranged in cross shape and 45 ° angle shape, and the height is two-thirds of the thickness of the sprayed coating layer. They are welded by electric arc welding process.
The spraying construction process is: pouring - mixing - Screening - air supply, water supply, feeding - spraying - trimming - cleaning. The coating spraying construction is generally simple without mold. It only needs to be equipped with a spraying gun to spray coating.
2. Precautions for spraying construction:
2.1 before spraying, place the batching station and equipment used for spraying, such as air compressor and spray gun, near the spraying work to better operate the working pressure of spraying machinery and material conveying pipe.
2.2 requirements for spraying equipment: air compressor is 0.6MPa, spraying gun is 0.4MPa, and spraying pressure of spray gun is 0.1-0.2mpa.
2.3 during spraying, the nozzle shall be kept perpendicular to the sprayed surface and about 0.8-1.2m away. During spraying, it shall move evenly from top to bottom in a spiral shape.
2.4 during spraying, pay attention to the speed of material flow at the nozzle to avoid dry material and flow during spraying. It is better to have small rebound, less dust, dense spraying, no interlayer and smooth surface.
2.5 check the spraying thickness after spraying. If it is less than the design thickness, it shall be sprayed again in time.
The quality of spraying coating and lining is not only related to the material itself, but also important for construction.
