Process key points and product characteristics of activated carbon fiber felt

Activated Carbon Fiber (ACF) is a material with the characteristics of both activated carbon and carbon fiber, which is generally used in the form of felt, cloth, etc. The carpet shape is activated carbon fiber felt. The raw materials of activated carbon fiber felt are mainly adhesive, polyacrylonitrile, asphalt, etc., and phenolic, polyethylene and other materials are also used.

From the point of view of process, the preparation of ACF can be summarized as precursor preparation, pretreatment, carbonization and activation. However, if ACF is obtained first and then felt, it is not reasonable because ACF fiber has small diameter, low strength and poor textile performance.

Therefore, just like ordinary carbon fiber felt, the preparation of activated carbon fiber felt is generally the precursor fiber is first made into felt, and then pretreatment, carbonization and activation.

Among them, the activation process is the key to make the difference between activated carbon fiber felt and ordinary carbon fiber felt. The activation methods are divided into physical activation and chemical activation. In the physical activation, the disordered carbon on the carbon fiber felt reacts with water vapor or air, or carbon dioxide at 800-1200 ° C, forming carbon monoxide, carbon dioxide, hydrogen, etc., which is taken out, and a large number of pores appear on the carbon fiber felt, of which 90% are micropores.

A large number of micropores make activated carbon fiber felt have larger specific surface area and stronger adsorption capacity than granular activated carbon.

The activation process not only makes the activated carbon fiber felt have a large number of pores, but also makes it carry oxygen-containing functional groups. Therefore, the non-carbon content of carbon fiber felt is increased after activation. The carbon content of activated carbon fiber is more than 90%.

In application, activated carbon fiber felt can be used for environmental protection filtration, as a key material in the fields of organic waste gas treatment, water purification, gas masks, dressings and so on. Moreover, the adsorption of activated carbon fiber felt is mainly physical adsorption, and the force between the adsorbed substance and activated carbon fiber felt is weak, so it is easy to desorption after heating, which is convenient for recycling of materials.

Process and product characteristics of purified felt

The name "purified felt" may make people think that it is the material used to purify pollutants, but it is not. Purified felt generally refers to high purity carbon fiber graphite felt. How do you get high purity felt?

First, the ingredients. In order to make the purity of the finished product higher, it is necessary to select viscose fibers and polyacrylonitrile fibers with very low impurity content. In addition, the filament fibers can be treated, such as reducing the metal elements in them.

The production process of purified felt includes filament preparation, nonwoven forming, pre-oxidation, carbonization, graphitization, and purification (purification). Impurities have many opportunities in this process, and at the same time, the process of carbonization, graphitization, and purification can gradually eliminate non-carbon elements. Generally, the graphitization temperature of viscose carbon fiber is about 1400-2400℃.

After graphitization, the carbon content of carbon fiber graphite felt can reach more than 99.9%. Subsequent purification will further remove impurities and increase the carbon content. Purification is the key process of purified felt.

The purification methods of carbon fiber graphite felt are mainly divided into high temperature heat treatment method and chemical treatment method. The high temperature heat treatment method needs to be carried out at 2500℃, and the chemical treatment method also needs to let the felt react with HCFCS in the furnace body at 2000℃.

Purified felt should be as pure as possible, and the ultimate purpose is to make it more suitable for thermal insulation in photovoltaic/semiconductor thermal fields with strict purity requirements. Because if the impurity content of the insulation material is high, it will cause the pollution of the semiconductor material and cause losses.

The carbon fiber graphite felt used in the silicon single crystal growing furnace will be slowly oxidized, corroded by silicon steam, and the impurities on the felt will gradually increase. The recovery of silicified purified felt is also more difficult than that of activated carbon fiber felt with adsorbed impurities.