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As an important material of cement kiln, the construction of refractory should be strict
Zhengzhou huixinlong refractory
As an important construction material of cement kiln, the quality of refractory masonry will directly affect the service life of cement kiln. Therefore, as a refractory manufacturer, providing reasonable construction technical support can highlight its own strength and increase the added value of its own products.
In addition, with the rapid development of cement kiln technology in recent years, the application and construction of large-scale and super large cement rotary kiln has brought about a very complex situation of refractory construction in some parts of the kiln. How to solve these construction difficulties?
Construction preparation before masonry
Before masonry construction, first, clear the construction task; second, do three checks, i.e. check personnel, materials and site; then, make preparations to eliminate hidden dangers and reduce problems; make plans to deal with possible accidents.
① Carefully analyze the drawings, clarify the construction tasks, understand the design intent, and clarify the design requirements and key points of each part
③ Inspect the refractory materials, construction machines and tools and auxiliary facilities and tools entering the site, confirm whether their varieties, specifications, quantity and quality meet the construction requirements, and whether the personnel and organizations involved in the construction meet the predetermined requirements.
④ Carefully inspect the construction site, and observe whether the kiln is cleaned and dried, whether the simplified body is deformed, whether the weld and connection are flat, and whether the brick retaining ring is perpendicular to the kiln axis. It is required to ensure sufficient lighting, smooth transportation, complete tools, mechanical and electrical integrity, and complete personnel. In case of mechanical and electrical equipment failure, it can also be eliminated in time.
⑤ According to the construction task and the actual situation of the site, the progress plan and cross operation plan of the masonry project shall be prepared, the construction technology, material and work preparation shall be well done, and the plan shall be prepared in case of failure, so as to ensure that the kiln lining construction can be carried out in a harmonious and orderly manner and meet the quality requirements.
6. Before bricklaying, after cleaning the site, set out. The longitudinal datum line of the kiln is placed every 1.5m along the circumference of the circle, and each line is parallel to the axis of the kiln. One circular datum line is placed every 10m, and each line is perpendicular to the kiln axis. In addition, it is necessary to draw construction control lines parallel to the circular or longitudinal datum lines, with one set every 1m.
Before masonry, various refractory slurries shall be tested and masonry shall be carried out to determine the setting time, setting time, frustrated consistency and water consumption of different slurries. The setting time of refractory products shall be controlled within 1-5min for air hardening mud.
Special mud tank shall be used for each type of mud preparation. If several kinds of mud need to be prepared, all kinds of mud shall be clearly marked. When changing the mixed mud, the mud tank shall be thoroughly cleaned.
Clean water shall be used for the preparation of fireclay, and the water quality shall meet the water standard of urban residents. For the mud with additives, the chloride ion content in the water shall be less than 300ppm.
When the temperature is too low, the mixing water can be heated to ensure the proper temperature of the mud.
For the air hardening fire mud, the masonry time of the mixed fire mud shall be more than 3omin. The prepared hydraulic and pneumatic fire mud shall not be used with water at will, and the fire mud that has been initially obstructed shall not be used again, so it shall be discarded resolutely. For the mud mixed with water glass or brine binder or admixture, as it will gradually solidify in the air, it should be used at any time. The fire mud of the day should not be left for the next day.
The firebrick shall be filled with mortar, and the width of the brick joint shall meet the design requirements of the drawing.
After each refractory brick is placed, it shall be knocked with a wooden hammer or rubber hammer to squeeze out more than fireclay. It is necessary to ensure that the brick joint is completely close to the shell. The firebricks shall be in face contact and firmly combined. When striking the refractory brick, it is necessary to prevent improper striking or extrusion from damaging the refractory brick or damaging the fire clay that begins to solidify.
Before the fireclay of brick joint is completely hardened, the excess fireclay shall be scraped off. If the fireclay needs to be filled in some places, the scraper shall be used to plug the new masonry joint.
The mortar joint shall be horizontal and vertical, the arc surface shall be flat, and the joint shall be tight, so as to ensure that the masonry is consistent with the dimension indicated by each equipment.
The straight wall shall be built with staggered joints, and the arch crown and kiln shall be built with straight joints in the circular belt. The masonry adaptability requires the straight arc surface of the brick joint; the geometry of the masonry shall meet the requirements of the drawings to ensure the quality
Metal components such as brick supporting plate and flange plate shall not be in direct contact with refractory bricks. The components shall be coated with fireclay, and about 10 mm expansion joint shall be left under the brick supporting plate. Fire resistant fiber felt can be inserted into the expansion joint to protect the brick supporting plate. The flange and metal device can be sealed with fireclay to avoid contact between metal device and high temperature gas.
Anchor brick masonry
Anchorage brick can improve the integrity of the straight wall. In the expansion and contraction of the metal shell of the equipment, there will be a gap between the metal shell and the refractory. The powdery material may fill the gap of the refractory brick gradually, which will lead to the collapse of the straight wall under the force perpendicular to the wall. During the heating process of the equipment, the refractory brick may also collapse due to the uneven expansion inside and outside. The use of anchor brick can greatly reduce the probability of two adverse changes.
The layout and masonry of anchor bricks shall follow the following principles:
The arrangement of anchor bricks shall be determined according to the change range and frequency of temperature and the size of the area of the straight wall, generally not less than 6 pieces / m2.
Before masonry, the anchor brick shall be carefully inspected. If there is any crack affecting the overall strength of the anchor brick at the anchor hole, the anchor brick shall not be used, and shall be discarded.
When the masonry is close to the anchor brick position, it is necessary to row the bricks in advance to determine the exact position of the anchor brick. It is to thoroughly clean the welding part of the metal shell with a wire brush, use the welding rod suitable for the welding parts, and firmly weld the anchor pipe.
Anchor brick masonry completed