Refractory gunning material for inner lining maintenance of blast furnace

Refractory gunning material for inner lining maintenance of blast furnace

The unshaped refractory material used when repairing the lining of thermal equipment by spray construction method is called refractory gunning material. It is composed of refractory aggregates with certain particle gradation, chemical binders and additives, and is generally a thermosetting or gas-hardening material. The selection of the main material is based on the maximum temperature fluctuation range that may be reached in the kiln, the properties of the slag, and the material of the lining itself.

The particle size composition and limit particle size of the gunning material and the spraying layer should be determined according to the structure of the gunning machine, the thickness of the gunning layer and different gunning methods. Improper selection of particle size or unreasonable particle gradation have a great influence on the adhesion of gunning material and the density of the gunning layer. Under normal circumstances, the wet and dry spraying particles are too coarse and too many particles will lead to a decrease in the adhesion rate. Generally, the multi-critical particle size of the dry gunning material is larger than that of the wet spray gunning material, and sometimes it can reach 6~7mm or even larger. Fire spray gunning material is divided into wet method (mud method) gunning material, semi-dry method (nozzle mixing type) gunning material and flame method (melting method) gunning material according to the construction method: according to the main material of the gunning material Divided into magnesia, magnesia-calcium, magnesia-chromium, magnesia-carbon, aluminum silicate and alumina-silicon-oxide-carbon gunning materials, etc.: according to the conditions of use, it is divided into gunning materials for converters and gunning for electric furnaces material, gunning material for ladle, gunning material for vacuum degassing furnace (RH, DH), gunning material for tapping ditch and gunning material for blast furnace lining, etc.

 Refractory gunning material characteristics are :

simple operation

high adhesion rate

rapid sintering, no dust

low rebound rate

mechanized or automated construction

shortening the construction period

saving labor

and reducing costs