With the continuous updating and progress of cement production technology, the single production line of cement kiln is developing in the direction of large-scale. The new dry process cement production technology has the characteristics of high kiln temperature, fast kiln speed, complex system structure, and serious erosion of volatile components such as alkali, which puts forward more stringent requirements for refractory materials used in cement kiln. Amorphous refractory has been widely used in cement industry because of its excellent performance, convenient construction, energy saving and other advantages, accounting for about 50%.
However, amorphous refractories have higher requirements for site construction quality, and are prone to excessive water addition on site, resulting in faster decline in castable performance and bursting during baking. The prefabricated part is the shaping of amorphous refractories, the preparation process is between shaped refractories and amorphous refractories, and the performance has the advantages of shaped and amorphous, which is a new direction for the construction and application of amorphous refractories, and has been rapidly developed in recent years.
1. Characteristics and requirements of refractory prefabricated parts
The pre-construction part is divided into small pieces in advance, and the appropriate shape is designed, and then the mold is made according to the shape, and then the factory is poured into shape, maintenance, baking and shipped to the site for construction and installation. The application of refractory prefabricated parts has changed the traditional casting construction method, so that the construction is simple and easy, can save the on-site mixing, pouring or ramming and the required corresponding equipment, greatly saving the construction time, and the site construction conditions are not affected by the construction environment and seasons, and is more conducive to ensuring the construction quality. In order to facilitate the production, transportation and installation, the shape of the prefabricated parts can not be designed too large and too complex, and as far as possible uniform size, in addition to the need to take into account the combination between the block and the block, so as to enhance the integration effect after construction. The construction parts need to be cleaned, otherwise it will affect the installation accuracy and effect of the refractory prefabricated parts.
Most of the parts used in refractory prefabricated parts are special parts in harsh environments such as high temperature, cement clinker erosion, wear, acute cooling and acute heat, which are easy to produce mechanical deformation, and need to have good erosion resistance, good wear resistance and high temperature gas erosion resistance and excellent thermal shock stability. To achieve the performance requirements, the ratio of raw materials is the basis, which is similar to the requirements of castable, but the castable needs to pay attention to the performance of the entire temperature range from construction to use conditions, and the refractory prefabricated parts, as the shaped products prepared by castable, pay attention to the performance after baking. Many manufacturers have listed the performance indicators of prefabricated parts under different temperature conditions, which is actually of little reference significance for cement manufacturers. In view of this situation, the raw materials and ratios used in refractory prefabricated parts can be adjusted on the basis of castable, and more attention needs to be paid to the performance after baking.
Refractory materials in key parts of cement kiln need higher construction quality in the construction process, and during the maintenance of cement kiln, the general construction period is short, the quality of on-site pouring construction is difficult to guarantee, and the quality of construction quality has a great impact on the service life of refractory materials. The increase of water added will increase the porosity of castable, decrease the strength, and seriously affect the wear resistance of castable. After the construction of castable, there must be a certain maintenance time, and it must be baked after the maintenance is completed, otherwise it is easy to burst.