Refractory spraying material construction method
Spray repair construction was first developed for converters, and then gradually applied to blast furnace bodies, torpedo tankers, electric furnaces, ladles, vacuum degassing devices, etc.
Spray repair method can be divided into dry method, semi-dry method and wet method according to the material transportation method.
The dry method is a method of transporting dry powder without moisture and adding moisture to the nozzle portion. The semi-dry method is a method of conveying a powder containing a part of water and adding residual water to a nozzle portion. The wet method is a method of transporting a slurry in which moisture is added. One of the purposes of developing semi-dry spraying is to avoid the complicated and complicated pre-mixing operation of the wet method. Because the advantages of using the wet method are relatively obvious, the current technical interest has turned to the wet spray repair method.
Spraying and filling construction equipment and operation
The key of spray repair technology is to have a set of spray devices that can operate normally. Different materials are used to spray different materials, and their performance and parameters are also different. In order to stably feed the low-moisture, high-viscosity and low-cement shotcrete, squeeze or screw pumps and air pressure spray sprayers should be used, and the pressure cannot be too low.
The following points should be grasped in the wet spray repair operation:
(1) Guarantee stable pressure feeding performance. The particle size composition of low cement shotcrete is closely related to the pressure feeding characteristics. With the increase of the added water, the disadvantage of clogging in the tube will occur during the pressure feeding process. Therefore, in order to achieve stable pressure feeding performance, it is necessary to adjust the optimal particle size composition range of the low cement shotcrete.
(2) Adjustment of hardening speed. The type and amount of the accelerator that imparts hardening properties have a great influence on the strength of the construction body. In actual construction, when the vertical construction surface is thicker, it is necessary to increase the strength of the construction body quickly; when the surface of the construction body after spraying needs to be processed, it is better to increase the strength slowly. Therefore, according to the construction conditions, it is necessary to select an appropriate coagulant and its addition amount.
(3) Formation of compact construction body. There is an optimal range of injection air volume for achieving compaction of the construction body, but the density is independent of the injection pressure.