What is the significance of wet injection tracking in blast furnace lining



The wet injection technology of blast furnace lining can repair a 5500m3 blast furnace lining in a very short time (48h), and the service life can reach more than 1.5 years. This rapid maintenance mode has been fully recognized by the vast majority of blast furnace users, and plays a huge role in China's green ironmaking technology.

The core of wet injection technology is "injection" rather than "spray", "injection" means no mold pouring, spraying to achieve the effect of pouring. At present, the market is filled with a variety of wet spray technology and products, most of them are hand-carried dry spray mode, spray material on the inner wall even if the completion of the job. In fact, concrete injection technology has been developed in the construction industry for over 100 years, and the injection of amorphous resistant castables is no more complicated than building materials. It is easy to "spray out and stick to the wall", but this goes against the idea of wet injection in blast furnace linings. Non-plate wall combined with blast furnace cooling wall, the lining basically falls off during the middle repair, and there are residual materials in the cooling wall brick groove. This smooth metal lining can still keep straight after the opening of the furnace even if it is not repaired. The success of a blast furnace injection lining is not a simple observation of whether the blast furnace is in line after opening, nor is it smooth or not, but the actual data reflected after opening. The lining of blast furnace is the key to protect the cooling wall and prevent excessive energy loss. Under normal circumstances, the coke ratio and comprehensive fuel ratio of blast furnace will drop significantly after the injection lining is opened. Combined with a lot of practical experience, this reduction rate is about 15% ~ 18%; The life of spray lining can also be inferred from these data.

In order to achieve the effect of wet injection, it is necessary to have uniform mixing material and stable pumping speed. High-pressure gas and coagulant are uniformly arranged at the nozzle head, and the following stable process parameters can be quickly adjusted at the initial stage of injection: the distance and Angle between the nozzle head and the wall, the feeding amount, the feeding speed, the gas supply and the coagulant dosage, etc. When the spraying material has the characteristics of pouring body, the output is stable. In the actual implementation process, the operator needs to adjust flexibly, so the early business training is very important. A good spraying interface is not smooth like plastering, but rough and clearly visible particles. The steps of wet spraying can only be done from bottom to top like pouring, and can not be sprayed from east to west. In this way, only furnace shape can be obtained, rather than life.

The energy saving and consumption reduction of blast furnace is not a simple choice of low - cost refractories. The development direction of wet injection technology is still more efficient, energy saving and longevity. Only by respecting research and development, technology and market, rather than blindly imitating, can we promote the progress of core technology and obtain good market application. (Expert Group of Beijing United Rongda Engineering Materials Co., LTD.)