Low cement castable has a series of advantages such as simple production process and convenient construction, and is very suitable for the use of heating furnace. The original heating furnace uses a large number of clay brick masonry, some parts still need to be processed to masonry, resulting in the overall performance of masonry is poor, low strength. The application overcomes the low strength of ordinary castable at room temperature, and makes up for the defect of poor strength of ordinary castable in temperature, improves its structure to improve its strength evenly. The material has the characteristics of anti-penetration, anti-erosion, anti-impact wear resistance, good mechanical properties, and has a wide range of applications. Today, let's talk about the application of low cement castable in heating furnace:
1. Process parameters
High aluminum clinker material, Al2O3 content in more than 70%, refractoriness at 1770℃, aggregate size requirements in 5-8, 3-5, 1-3 particle level; Fine powder using high aluminum clinker fine powder, particle size < 0.088mm no less than 90%, and requires uniform and reasonable particle distribution, so as to have better compactness and high temperature performance.
High aluminum cement label is not less than CA-50, refractory is not less than 1400℃, the dosage is controlled at about 5-8%.
2. Construction method
The 25kg bag of low cement castable is mechanically stirred, and appropriate amount of tap water is added according to the instructions. The mixed mixture can be tightly held into a ball by hand. After the inner side of the steel plate of the furnace shell is well constructed, such as the fiberboard, light firebrick and anchor brick, etc., the formwork is then supported for construction.
The construction should be continuous construction, each layer of paving material should not exceed 300mm, vibration, vibration rod to fast insert, light pull, slow movement, pay attention to prevent the cavity caused by vibration rod, affect the quality of pouring. Expansion joints shall be reserved for castables in accordance with the design and specifications, with an expansion joint every 2000mm. During construction, the expansion joints shall be filled with fiber cotton or fiberboard. 48h after the end of natural curing, remove the formwork, and bake according to the oven curve. Especially at 150℃ and 350℃, free water and crystal water in castable should be completely discharged.
3. The use effect
Through the observation of the use of low cement castable in the heating furnace for nearly 4 years, the overall performance of the furnace body is very good, the surface does not fall off phenomenon, the refractory material of the furnace body is basically not damaged, the surface temperature of the furnace shell is about 70℃, the single consumption of forging gas is reduced from 5300m3/t to 3500m3/t, and good economic effect has been achieved. Low cement castable used in heating furnace, not only reduces the amount of bricks, improves the labor intensity of construction, shorten the construction period, and castable lining integrity is good, excellent insulation performance, greatly reduce energy consumption, so as to achieve the effect of energy saving and emission reduction. Compared with the early clay brick, the price of castable is 3 times that of ordinary clay brick, but the service life of kiln is increased 5 times, and the economic benefits are obvious.
With the continuous development of refractory technology, many enterprises now also use the precast made of low cement castable to build the kiln, its advantage is that the refractory precast will be baked in the factory after production, after the site can be installed directly, reduce the construction time, and reduce the existence of free water, in the oven will be more effective to eliminate water, improve the service life of the kiln.
