1. What is the reason for cracked waste products in the roasting process of carbon products?

Generally speaking, due to the reasons of the previous process, the product often has transverse cracks and internal cracks. However, due to the reasons for this process, the products are often arranged in columns, and the reasons for various cracks are as follows:

1)The material temperature is too low during molding, the pre-pressure is insufficient, and the molding pressure is insufficient.

2)The paste is broken during the return process of pressing, resulting in poor internal structure.

3) The degree of calcination of the raw materials is not enough, or the ingredients are mixed into the raw material block, resulting in secondary shrinkage during calcination.

4)Too much oil is applied to the plunger head of the press, and the joints of the two pots of materials will not stick together, and cracks will occur after roasting.

5)The content of the binder in the product is too small, and the content of the powder is too much.

6)The paste is unevenly kneaded or there is water in the paste.

7)The heating rate is too fast.

8)The product is too close to the furnace wall when it is installed in the furnace.

9)Partial leakage of the furnace wall, heating too fast.

10)The upper layer is equipped with large-scale and less-ash products.

2. What is the reason for the oxidation waste produced by the roaster?

1)The upper insulation material of the product is too thin.

2)Material leakage in the furnace chamber and ventilation of the motor box.

3)The moisture content of the filling material is too large, the material is not solid, and the product shrinks and sinks during  firing to expose the product to oxidation.

4)The temperature was too high when it came out of the oven, and the product did not disperse in time at the cleaning site.

3. What are the reasons for cracked waste products in the graphitization process?

Cracks generated during graphitization appear on the surface and inside of the product due to thermal stress caused by temperature differences during heating. There are three types of cracks observed on the product surface: longitudinal cracks, transverse cracks, and network cracks. It is generally believed that longitudinal cracks are caused by the poor quality of baked products, which are related to several processes before graphitization, while transverse cracks or network cracks are more related to the graphitization process.

1)When the furnace is loaded, the products are not arranged neatly, and the filling of the resistance material is uneven, and then there is the phenomenon of "shelf material" of the resistance material.

2)The power transmission system is unreasonable, and the selected power-on starting power and rising power is too high, resulting in a too-fast heating rate. The temperature difference between the surface and the interior of the product increases, and the thermal stress caused by the temperature difference leads to cracks.

3)When metallurgical coke and graphitized metallurgical coke mixture are used as resistance materials, if the mixture is uneven, the furnace core current will deviate, resulting in the uneven temperature of various parts of the furnace core, and a large number of cracked waste products will easily be produced.

4)The production of the first few processes of graphitization is unstable, such as the low temperature of calcined material, low temperature of the roasted product, unqualified weight gain rate of the impregnated product, etc., the quality fluctuation of carbon billet caused by it will be concentratedly exposed in the graphitization process, that is During the high-temperature treatment of graphitization, the secondary shrinkage or uneven shrinkage of the aggregate inside the product is easy to produce cracked waste products.

5)The bias current of the graphitized furnace core will sometimes produce transverse cracks.

Please contact us if necessary.