Pre carbonization is the process of carbonizing negative electrode powder made from coated granulation or raw petroleum coke/needle coke. The main purpose of carbonization is to remove the volatile components from the negative electrode powder and cause the particles to initially shrink after transformation. This will be beneficial for increasing the compaction density of materials, increasing the amount of graphite filling, and reducing production costs. At the same time, the pre carbonization process can increase the carbonization comparison surface area, improve the characteristics of negative electrode materials, and optimize battery performance, which plays an important role. The carbonized negative electrode material accelerates the electrode reaction rate, reduces resistance loss, and improves the cycle life of the battery. Therefore, the pre carbonization process is very beneficial for improving battery performance. The pre carbonization temperature of negative electrode materials is generally 1250 ℃ (actual materials must reach 1050 ℃ or above), and the high temperature period should be maintained for no less than 8 hours. The pre carbonization tunnel kiln designed and manufactured by our company is a new type of product developed in recent years. The kiln design has absorbed advanced technologies from domestic and foreign kilns, comprehensively considered special carbonization roasting requirements and the characteristics of negative electrode raw materials, and comprehensively improved our company's original design and construction of carbon electrode two baking tunnel kiln, lightweight structural ceramic tunnel kiln and other practical experience. Reasonable material selection has been made, and low heat storage high-end composite lightweight refractory materials have been used. The kiln body is light and has low heat storage and dissipation. The layout of the kiln top exhaust pipeline should be reasonable to ensure that the combustible volatile matter in the product evaporates and burns inside the kiln as much as possible. At the same time, a waste gas incinerator should be set up to effectively collect and incinerate a small amount of residual volatile gas, achieving environmental emission requirements, low energy consumption, high degree of automation, and convenient operation and control.
The process flow of pre carbonization tunnel kiln for negative electrode material is as follows:
Manual/automatic canning - shuttle car transportation - top car machine feeding into the kiln - natural gas burner heating up - roasting - volatile matter decomposition overflow incineration - kiln insulation roasting - kiln cooling - kiln exit - shuttle car transportation - kiln cooling - manual/automatic unloading - manual/automatic canning