Preparation and operation process of refractory spray coating for blast furnace hot blast stove

The construction rules for refractory spray coatings for blast furnace hot blast stoves are collected by refractory brick manufacturers.

Paint spray construction is a relatively important process for hot blast stoves. The construction quality of spray paint lining is the guarantee of the furnace body’s sealing and heat preservation performance. The spraying construction has strong continuity, and the spraying process should reasonably adjust the air pressure and water addition according to the delivery distance and construction height of the sprayed paint on site. The operator must have more skilled spray paint construction experience.

1. Preparation before spraying:

(1) Check and confirm that the roots of the anchoring nails are firmly welded (it is the quality standard that the anchor nails bend and not fall off by hitting the anchor nails with a hand hammer), and there is no phenomenon such as fusing or desoldering. The specifications and spacing of the anchoring nails meet the design and construction requirements. .

(2) Debug spraying construction equipment, appliances, etc. to make their working wind pressure and water pressure meet the specified standards and pass the trial operation.

(3) The amount of spray paint should meet the requirements of continuous construction operations. The proportion of raw materials and water added should be carried out in strict accordance with the use and construction instructions. After the trial spray is qualified, the formal construction can be carried out.

(4) Check the test weight of the hanging plate for spraying construction, the test run is qualified, the safety rope, the lifting point, etc., check and confirm the quality and safety, and ensure the stability and smoothness of the real-time communication signal between the upper and lower sides.

(5) Check that the grid plate is installed in place and check to confirm that it meets the design and construction requirements.

2. Operation process of spray paint construction:

(1) Before spraying, evenly stir the spray paint according to the preparation instructions, then place it in the spraying machine, and turn on the spraying machine for air and material feeding.

(2) Before spraying, clean the construction area with high-pressure air and moisten it with water before spraying.

(3) The spraying operation sequence is air supply → water supply → material feeding, and the sequence is reversed when spraying is stopped.

(4) The spraying of the straight cylinder section should be from top to bottom, from left to right, and the spray gun moves down gradually along the circumferential direction. The thickness of each spray should be controlled between 40-50mm, and the parts with a thickness of more than 50mm should be divided into two parts. Or spraying for many times to meet the requirements, the spraying construction of the top of the arch should be circled from the bottom to the top.

(5) The spray gun should be perpendicular to the construction surface and the distance should be 1.0~1.2m, and the wind pressure and water pressure should be adjusted at any time according to the site conditions; the amount of spraying should be based on the micro drop of water on the surface of the coating, and it needs to be divided into two or more times. For spraying construction parts, the upper and lower spraying time should be controlled within the initial setting time.

(6) The reserved expansion joint position of the spray coating layer should be at each section or square grid joint. After spraying is actively interrupted or passively interrupted, the interrupted area should be sprayed with the coating layer and the interrupted joint should be sprayed with water first. Construction can only be carried out after being wet.

(7) During the construction process, check the thickness and radius of the spray coating layer at any time and adjust them in time to ensure that they meet the design and construction requirements.

(8) After the construction of each section/area of ​​the refractory spray coating is completed, start leveling treatment, first rough repair, after finishing and smoothing the large concave surface, use a radius gauge or arc board to finely level it again.