Castable Construction

With the continuous increase of cement clinker production lines in the country, the requirements for the construction and use of refractory castable are getting higher and higher. In order to better use refractory castable and reduce the consumption of castable, KENUO has summarized and explored a set of castable construction plans based on years of construction of castable and research on castable, which are briefly described according to the construction process.

Construction plan:

1. The castable should be stored in a warehouse with a roof, and should not be exposed to rain or moisture. The shelf life is five months.
2. Before construction, check whether the steel anchors are firmly welded. The material of the steel anchors is 1Gr18Ni9Ti, and the high temperature area such as the kiln inlet and the coal injection pipe are 0Gr25Ni20. The steel anchors are “Y” or “V”-shaped, with a diameter of 8~16mm. The steel anchors are arranged in a criss-cross shape, and the spacing between the steel anchors is 180~200mm (usually determined according to the thickness of the lining). The lower end of the steel anchors should be made into an L shape, and the length should not be less than 25mm. The steel anchors should be fully welded on both sides during welding, and the welding should be firm.
3. The surface of the steel anchors and the metal components buried in the castable shall be coated with asphalt paint, and the head shall be covered with a plastic cap to buffer the expansion stress after heating.
4. During the construction of castable, the expansion joints should be strictly controlled in accordance with the specifications and specified in accordance with the expansion joint coefficient. Use linoleum paper or rock wool to leave expansion joints on the brick surface in contact with the castable.
5. The formwork used in the formwork construction should be waterproofed. The surface of the template should be smooth. In order to prevent the mold from sticking, the surface of the template should be uniform wiped with an appropriate amount of oil before installation, so as not to flow. Formwork joints should be aligned and sealed to prevent steps and grout leakage in the lining.
6. The construction site is required to be clean, and no other debris such as sand, lime, Portland cement, etc. shall be mixed into the castable, and all tools and equipment in contact with the castable shall not be stuck with the above substances.
7. During construction, a forced mixer should be used to mix materials, and manual shovel mixing should not be used. Mixing of different grades of castable is strictly prohibited.
8. When using, pour all the materials in the whole bag into the mixer.
9. The suitable construction environment temperature is 10- 30 degrees. During construction in summer, it is strictly forbidden to put the castable in the open air, it should be placed in a cool place, the construction site should be shaded, and the mixing water temperature should not be higher than 20 degrees; during construction in winter, when the ambient temperature is lower than 5 degrees, it should be Use warm water (40 degrees ~ 60 degrees) to stir, after construction, take appropriate insulation measures to keep the ambient temperature above 5 degrees, and the demoulding time is not less than 48H. When the construction environment temperature is lower than -5 degrees, construction is strictly prohibited.
10. When stirring, first dry and mix uniform and then add water. The water used in construction should be fresh and clean drinking water, and its PH value should be controlled between 7~7.5.
11. Water should be added according to the amount of water added to different products, and should not exceed the maximum amount of water added.
12. After adding water, the stirring time is 2~3 minutes. It should be stirred uniform, and there should be no dry material and agglomeration. The mixed material should be used up within 30 minutes. The coagulated material should not be mixed with water and should be thrown away.
13. The height of one loading in the template shall not exceed 300mm. After the material is loaded into the template, it should be spread uniform. The vibrating rod should be inserted straight, fast in and slow out, and the insertion depth should be 100mm to the next layer of lining to ensure the connection of the upper and lower linings. The distance between the rods is 150~200mm. It is advisable to return the slurry to the surface of the material. (Generally 20~40 seconds)24 hours after casting, demoulding, and natural curing for 24 hours after demolding.

Sub-construction plan:

1. Construction plan of preheater:

1.1 During the construction of the preheater, expansion joints should be left at the places where the castables in some places are in contact with the refractory brick surface, and the expansion joints should be filled with linoleum paper or rock wool.

1.2 When constructing the top of the preheater, the general construction is that the anchors are welded on the lower surface of the top steel plate, the formwork is supported from the bottom, and holes (2 per square meter) are cut on the top steel plate, and the vibrating rod is inserted through the holes for vibration and compaction. Therefore, attention should be paid during construction:

a. When the vibrating rod is inserted into the hole for vibration, when the vibration distance is too large and it is difficult to operate, it should be vibrated as uniform as possible, especially in the joint of the old and new castables, no holes should appear;

b. Operation During construction, do not vibrate and skew the expansion joints in the castable to lose its due effect;

c. The pouring speed of the castable from the hole is slow, so it is not to be very thick when mixing the castable. If it is very thick, it will directly affect the use effect.

1.3 When constructing the unloading pipe on the preheater, it should be cast by supporting formwork. When there is a elbow pipe, it can be constructed by hand. During the construction by hand, not to add too much water to the castable, mix it uniform is ok. During construction, in order to ensure the bubbles in the castable vibrate out. It can be divided into four parts for construction.

1.4 Ventilation holes should be opened in the castable parts such as the dome of the preheater and the upper elbow of the decomposition furnace.

2. The construction plan of the kiln hood:

2.1. Ventilation holes should be reserved in the construction of the castable of the kiln hood to prevent the castables from being heated too quickly during the ignition and heating process, and the internal moisture cannot be discharged in time, resulting in asymmetric temperature of the inner and outer layers, causing the castables to crack or even fall off. The specific drilling requirements are as follows. Use a punching drill to drill holes with a spacing of 300mm × 300mm.

2.2 After the casting hole is closed, 8 ventilation holes should be reserved to ensure the waterproof function.

3. The precautions for the construction of the refractory material on the sloping roof of the kiln hood are the same as those for the construction of the top of the preheater.