Understand the raw materials and production process of black cat carbon black

The raw materials for the production of pigment black cat carbon black are petroleum products and bituminous coal tar products. It is formed by incomplete combustion or pyrolysis of hydrocarbons at high temperatures.

1) Lamp black production process

The earliest carbon black production method in history is the lamp black production process, in which the raw materials are burned on a flat burning iron plate with a diameter of up to 1.5 m, and the combustion gas containing carbon black is laid by bricks inside. The hood is collected and then passed through a bend (bent 1/4) and a venting tube to the deposited device. In order to control the characteristics of the produced carbon black, it should be ensured that the raw material is mainly incompletely burned in the vicinity of the gap between the combustion disk and the exhaust hood. In a slightly pipeline, the combustion is thermally deficient in the absence of oxygen, thus forming larger carbon black particles. For these reasons, a wide range of particle size distribution is formed, mainly characterized by coarse particles. Since only a small portion of the particles formed between the combustion disk and the hood gap can be in contact with the oxygen in the air, these carbon blacks have only a small amount of surface oxide, the corresponding pH is neutral, and the volatiles are extremely small.

2) Production process of gas black

The name of gas black originates from its production process: the raw material hydrocarbons are first gasified when heated, and then the self-igniting gas (with energy) is carried as a carrier to the burner. The environmentally friendly black cat carbon black is in these bat-shaped burners. Generated in a large number of fan-shaped flames. Since each flame is small and burns in the air, the formation of carbon black is very different from the lamp black production process (not all combustion). Here, the carbon black particles are very fine, and according to different types, the average particle diameter is between 10 and 30 nm, and the average particle diameter of the gas black is 13 nm. On the burning flame, it is a slowly rotating water-filled drum. Carbon black is deposited on the drum. After scraping to scrape off the carbon black, when the temperature is still high, the newly formed carbon black is in contact with the oxygen in the air. Partial oxidation then occurs, forming a large number of acidic groups, and the corresponding gas black pH is in the acidic range. About 6% of the volatiles are obtained, representing the surface oxide content.

3) Production process of slot black

This production process uses natural gas as a raw material. The blackening process is similar to the gas burning process of the gas black production process. Natural gas is burned and many fan-shaped flames are emitted. The obtained product is similar to gas black, but the difference is that flat water cooling is used here. The U-shaped groove serves as a deposition tank for black cat ink black. The use of this method was stopped many years ago for ecological and economic reasons. The production of gas black will not affect the ecological environment, and this gas black process is still in use.

 4) Furnace black production process

Gas black is produced in an open atmosphere, but the furnace black production process is carried out in a closed furnace under anoxic conditions. Instead of using a lot of small fires, it is a large flame, using oil as a raw material, and adding a combustible gas to reach the required temperature in the furnace. By changing the conditions of the furnace black production process, the desired pigment black can be obtained. For example, under different conditions, black cat rubber special carbon black can reach a wide range of average particle size, from 80 nm to as small as 15 nm, and even smaller particles as small as gas black. However, for the same particle size, there is still a difference between gas black and furnace black, mainly due to different surface chemistry. The furnace black product is relatively rough with an average particle size of 40 nm. Further, when a furnace black production process is employed, a small amount of a basic compound or other additives may be added to change the aggregation degree and type of the aggregate, whereby a high structure or a low structure carbon black can be obtained.

Because the furnace black is produced under conditions of almost sub-atmospheric pressure and insufficient air. Therefore, most of them lack acidic surface oxides, but found the pyridone structure which is alkaline reaction mentioned above. Regarding the alkaline pH of the furnace black, it is because the alkaline earth is added to the spray-quenched cold water at the time of terminating the formation of carbon black, and the alkaline salt added for the structure is lowered. In addition, if the furnace black is no longer subjected to post-oxidation treatment, its volatile content is low.