In the industrial production of carbon anode materials for lithium ion batteries, powdery carbonaceous intermediates are often subjected to heat treatment at 900°C-1400°C, which is usually called carbonization treatment in the industry, and the corresponding equipment is called carbonization furnace. Some types of carbonaceous intermediates have significant changes in charge and discharge performance after carbonization treatment, and can be directly used or sold as anode materials, and some types of carbonaceous intermediates need to be graphitized at higher temperatures before they can be used. The graphitization process is a high energy consumption and high cost production process. Pre-carbonizing them before graphitization will significantly increase the material packing density, increase the single-furnace output of the graphitization furnace, and reduce the production cost of the graphitization treatment.
Tunnel kiln, as a type of high-temperature continuous roasting carbonization furnace, has many advantages such as large output, short cycle and low energy consumption, and is widely used in ceramics, glass, electric carbon and other industries. The roasting process mainly uses a boat-pushing furnace (roller kiln). Although the boat-pushing furnace is also a continuous production, it has the disadvantages of low output due to small furnace size and high energy consumption caused by electric heating. The use of graphite boats is easy to oxidize, and the cost increases, resulting in a high cost of 3000-4000 yuan/ton for roasting powder in the push boat furnace. In order to increase efficiency and increase production, it is imperative to use tunnel kilns for roasting.
Using continuous tunnel kiln for high-volatile carbon anode electrode powder for high-temperature roasting and carbonization can not only fully meet the temperature conditions (900-1300℃) required for roasting and carbonization, but also greatly increase the output. The use of oxidized sintered silicon carbide The material crucible can better solve the pollution problem of carbon negative electrode materials, and has high strength, high temperature resistance, no oxidation, and many repeated uses, which can effectively reduce costs and increase benefits. Generally, the tunnel kiln is about 100-130 meters long, and the daily output can reach about 30 tons. The raw material for heating in the tunnel type continuous carbonization furnace can be natural gas, coal bed methane, producer gas, etc., and the cost of raw material consumption is low. Under the condition of the same equipment capital investment, the output of the tunnel kiln is more than three times that of the push boat furnace (roller kiln), requiring very little labor. The comprehensive cost of carbonization per ton of product is less than 1,000 yuan (including all expenses such as fuel consumption, power consumption, auxiliary material consumption, crucible consumption, labor cost, etc.), and it can be applied to high-temperature carbonization (re-coating carbonization after graphitization).
The advantages of high temperature continuous carbonization of lithium battery anode materials in tunnel kilns are explained below:
1.Reasonable segmented temperature curve layout, burner distribution and flue gas pipeline design of tunnel-type carbonization kiln use the volatile matter of the product to fully burn, and the reasonable combustion air mix ratio ensures that the product can achieve the purpose of clean production under the condition of low energy consumption
2.The special fire channel design and the special silicon carbide flame sleeve can make the crucible products evenly heated, the temperature difference of the cross section is smaller, and at the same time, it can avoid the local deformation of the crucible due to excessive heating temperature
3.According to the characteristics of a large amount of combustible and volatile gases in the high-temperature carbonization process of the product, the use of medium and high-speed burners and automatic kiln pressure control system makes the temperature distribution more uniform, saves fuel, reduces temperature difference, and prevents deflagration. Oxygen content timely controls the combustion air supply to ensure the combustion atmosphere in the furnace. The gas part adopts German technology products to ensure production safety, energy saving and high efficiency
4.Specially designed gas-specific air/gas proportional mixing valve to ensure sufficient combustion in the furnace and stable atmosphere
5.The tailor-made lightweight furnace structure not only reduces the heat storage of the kiln body, the top of the furnace is made of 1.0-density lightweight mullite insulation bricks, which can withstand high temperature above 1350 °C, and is bonded with high-temperature adhesive to ensure the kiln. The sturdy structure of the body prevents dirt from falling, and the maintenance cost is minimized
6.Unique crucible and charging protection design can effectively prevent product oxidation and improve product quality
7.Special cooling method design, unique slow cooling structure, make the product cooling effect better and can effectively protect the crucible
8.The carriage return line is designed to facilitate unloading and loading, which greatly reduces the labor intensity of workers.
Prominer has long term cooperation with carbonization furnace producing factories in China and has rich experience in carbonization process for different kinds of anode materials and is capable of providing full set of anode material carbonization process solutions.