Remote-operated and hot-state spray repair solution for blast furnace and hot blast stove

The blast furnace lining is continuously damaged due to alkali metal corrosion, iron oxide corrosion, thermal stress destruction, thermal shock damage, and mechanical damage caused by furnace wear, dusty airflow and other special properties, and blast furnace The damage of the lining is characterized by uneven erosion, so that the lining is partially good and the other part is seriously damaged. If the repair or overhaul is carried out due to local damage, it is necessary to remove all the original brick linings, and it takes time and labor. Therefore, our company's blast furnace repair technology blast furnace remote spray method can solve these problems well.

Remote-operated and hot-state spray repair solution for blast furnace:

The spray coating material used in the blast furnace spray method is prepared from various refractory aggregates and powders, plus appropriate additives. Our company's remote thermal injection is to put the robot into the furnace through the opening of the furnace wall, and hang it on the bridge. The operator can observe and adjust the TV screen through the TV screen. This spray technology has the following advantages:

1.     Fast construction speed: remote spraying can reduce at least two-thirds of the construction time than bricklaying, with high economic benefits.

2.      High construction quality: The feeding speed, water addition and wind pressure can be controlled conveniently and accurately by remote control equipment, so that the rebound rate is low, and finally a uniform and dense spray coating lining is formed.

3.     Easy to open the furnace, so as to improve the utilization coefficient of the blast furnace: remote control spraying does not need to completely stop the furnace, only need to reduce the material surface to a suitable height, the material surface can be sealed with sealing charge. At the same time remote spraying can be required to restore furnace shape.

4.     High construction safety: no need for workers to enter the blast furnace, only need to spray the spray gun through the TV screen outside the furnace, so the workers are prevented from gas poisoning, falling, bruising, bruising and other accidents.

Our company can also carry out traditional cold spray and long gun spray. Ordinary cold spray repair requires scaffolding or hanging basket in the blast furnace to be injected into the blast furnace by the construction personnel. The advantage of this spray repair technology is that the spray repair equipment is simple, the slag skin and the loose residual lining are flexible, and the bare steel plate welding anchor is used. It is convenient to install small water-cooled parts and replace the cooler, and the spray-removing parts and thickness are easy to control, but the construction environment is poor. Long gun spray needs to open holes in the furnace wall or use the original manhole, and the operation operator stands outside the furnace to spray the part of the damaged brick lining. The advantage is that the personnel do not enter the furnace, the construction is simple, and the spray can be performed under the temperature regulation condition. At the same time, if it is only partial damage, this method can save time and cost. The disadvantage is that holes need to be made in the furnace wall.

Main construction instructions for spraying:

1.     Prepare the necessary construction equipment and tools for spraying.

2.     Before spraying, apply compressed air to purge the surface of furnace shell to be blown, and the sundries on the anchoring parts must be cleaned.

3.     Apply spray gun to the test spray before spraying. After the spray paint and water reach the best condition, the spray can be officially sprayed.

4.      Add appropriate proportion of aluminate cement before spraying, stir for 2-3 minutes, then add 3%-5% water, then stir for 5 minutes to discharge.

5.     In order to avoid tube-clogging after coating spraying is wetted, screen should be applied before spraying machine.

6.      When spraying, adjust the amount of water according to the dry and wet condition of the sprayed surface after spraying. If there is runny or slumping of the sprayed paint, reduce the amount of water added. If the amount of rebound is too large, increase the amount of water added. The appropriate amount of water is generally 12-16% according to the weight of the spray paint.

7.     When spraying, generally, it should be carried out from bottom to top and sliced. Leave an expansion joint at intervals of 1-2 meters. The width of the expansion joint is generally 1-3mm.

8.     The spraying direction should be perpendicular to the surface to be sprayed, and the distance between the nozzle and the surface to be sprayed is easily about 1 meter. During operation, the nozzle should be continuously spirally moved to make the coarse and fine particles evenly distributed. The diameter of the winding is 300-400mm. The spraying area should not be too large, generally controlled at 1.0-1.5m²

9.     Spraying should be carried out in sections and continuously to the design thickness. If thicker is required to be sprayed in layers, the secondary layer should be completed before the initial coating is applied until the design thickness is reached.

10.  When the spraying construction is interrupted, it is better to make a stepped joint at the expansion joint, and the joint should be slightly inclined inward. When re-spraying, spray water to the joint to wet.

11.  The thickness of the sprayed layer should be checked in time. When the sprayed layer is initially set, the surface should be adjusted, but it cannot be smeared. The surface of the sprayed layer should be as flat as possible. No cracks, interlayers, honeycombs or voids are allowed.

         12.  After spraying spray coating construction, natural curing to initial condensation.