The spraying material is composed of refractories, chemical binders and additives with a certain particle size distribution. The unshaped refractories used in repairing the lining of thermal equipment are used by spraying construction method. It is a main type of jet material.
Main types of gunning materials
According to the material status and injection method, gunning can be divided into three types.
(1) wet gunning can only be repaired by thin layer.
(2) dry gunning (also known as semi dry gunning) can be used for thicker layer spray repair, the most widely used.
(3) By flame spraying, a compact spraying layer with high bonding strength and erosion resistance can be obtained.
According to the state of spraying material on the spray face, it can be divided into:
(1) The melting material injection method is divided into three kinds: flame injection method, plasma injection method and slag splashing furnace protection method. 
(2) Cold material injection method is divided into five kinds: mud injection method, dry injection method, semi-wet injection method (or called tidal injection method), mixed injection method and wet injection method.
Particle size composition of gunning material
The particle size composition and the limiting particle size of the spraying material should be determined according to the structure of the spraying machine, the thickness of the spraying layer and different spraying methods. Improper particle size selection or unreasonable particle gradation has a great influence on the adhesion of the spraying material and the density of the spraying layer.
chemical composition,% ≥
bulk density, g/cm³ ≥
C.C.S, MPa ≥