Impregnating method of preparing isostatic pressing graphite product

Abstract

The invention discloses an impregnating method of preparing an isostatic pressing graphite product. The impregnating method comprises the following steps: preheating the isostatic pressing graphite product by raising the temperature from room temperature to 330 DEG C; placing the preheated isostatic pressing graphite product in liquid asphalt to form an impregnating system, and applying pressure to the impregnating system, wherein the temperature of the liquid asphalt is 180-220 DEG C; after the applied pressure remains unchanged, cooling the impregnating system under the condition of pressurization until the temperature is 50-60 DEG C; and heating the cooled impregnating system until the temperature of asphalt in the impregnating system is above a softening point, while stopping heating when the temperature of the surface of the product is at the softening point of the asphalt, meanwhile, reducing the pressure of the impregnating system, discharging the asphalt, then cooling the impregnating system again until the temperature is 60-80 DEG C, and finishing impregnation. According to the impregnating method disclosed by the invention, isostatic pressing graphite is uniformly and deeply impregnated in the impregnating process, the problems of cracking, bursting and the like in the whole impregnating process do not occur, the growth rate of the impregnated graphite product is increased, and the asphalt on the surface of the graphite product can be recycled again.

Description

technical field [0001] The invention relates to a method for preparing an isostatic graphite product, in particular to an impregnation method for preparing an isostatic graphite product. Background technique [0002] At present, the impregnation process of high-grade graphite products adopts gaseous pressurization. Due to the limitation of pressurized pressure, the impregnation depth of graphite products is not enough, the uniformity is poor, and the weight gain rate is low. Therefore, high-grade isostatic graphite products cannot be produced. In order to achieve the ideal state, the repeated cycle of the dipping process increases the cost and prolongs the production cycle. [0003] Now we have the impregnation technology of isostatic graphite products mainly from the impregnation process of high-grade graphite products. It has a large particle size ratio, and it is pressed from a powder that is 4 times finer than flour. Therefore, the preparation method of ordinary graphi...

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Problems solved by technology

[0005] However, the process of isostatic graphite products is more detailed, and the gaps between the products are smaller. The existing impregnation process is adopted, and the preheating process is free to heat up. This process can still be used in summer, but in winter graphite products are in the warehouse or It is because the temperature is low at room temperature (especially the lowest temperature in the north is minus 30°C). If preheating is carried out according to this process and the temperature rises too fast and too high, the thermal expansion and contraction effect of graphite products will start to play, and the products will be easily damaged and damaged. Burst, the same reason is the same in the cooling stage of the existing impregnation process. In a high temperature environment, water is suddenly injected for forced cooling. Without cooling control, graphite products can also produce thermal expansion and contraction effects, resulting in damage to the product.

Some manufacturers do not use any cooling measures for the cooling stage in the impregnation process of isostatic graphite products, and let the products cool down naturally in the impregnation tank. In this case, it takes nearly 48 hours to achieve the temperature drop to twice the normal temperature. Cooling, which delays production, also affects the impregnation uniformity and surface smoothness of the product

[0006] For isostatic graphite products, after the existing impregnation process is completed, the weight gain rate of the product is very low, the impregnation depth is poor, and the impregnation uniformity is even more of a problem.

Because the asphalt inside the product is not well protected during the cooling stage, the temperature of the asphalt is still much higher than the softening point of the asphalt, and the fluidity of the asphalt is better. At this time, the pressure is still used to prevent the asphalt inside the product from overflowing. In an instant, the asphalt will continue to overflow to the outside of the product, resulting in very uneven residual asphalt inside the product. After the asphalt in the tank is drained, water will be injected directly to cool it. During the water injection process, the temperature of the product itself is much higher than the softening point of the asphalt. , the asphalt inside the product is still overflowing outwards. After the product is completely cooled by water, the asphalt overflowing in the later stage of the product will stick to the last layer of the product surface, so that the asphalt inside the product is not uniform, and the overflow All the asphalt will go to the next process with the product, which also wastes a lot of asphalt

When the production of the next process is carried out, due to the uneven pitch in the product, the corresponding force is also released unevenly, and the force will find the weakest place, which will of course lead to cracks in the product and cause huge damage to the enterprise. Loss

The existing impregnation process not only delays the production, but also affects the impregnation uniformity and surface smoothness of the product, and the most important thing is to cause great economic losses

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