Many friends don't know how carbon black is made. In fact, carbon black is a product produced from petroleum and pitch coal tar. Carbon black cannot be produced under conditions of subatmospheric pressure and insufficient air, but is formed by incomplete combustion or pyrolysis of hydrocarbons at high temperatures.
How is lamp black produced?
The earliest carbon black production method in history is the lamp black production process. In this process, the raw materials are burned on a flat burning iron plate with a diameter of up to 1.5m, and the combustion gas containing carbon black is exhausted from The gas hood collects, then passes through elbows and flues to the deposition unit. In order to control the characteristics of the carbon black produced, it should be ensured that the raw material is mainly incompletely burned near the gap between the combustion disk and the exhaust hood. However, in the slightly entering pipeline, the combustion will undergo thermal decomposition under insufficient oxygen, thus forming larger carbon black particles. Due to these reasons, a wide range of particle size distribution is formed, and the main feature is that the particles are coarse. Because only a small part of the particles formed between the combustion disc and the exhaust hood can contact with the oxygen in the air, these carbon blacks have only a small amount of surface oxide, the corresponding pH value is neutral, and the volatile matter is very small.
How is gas black produced
The name of gas black comes from its production process: when the raw material hydrocarbon is heated, it is gasified first, and then it is carried into the burner by the spontaneously combustible gas (providing energy) as a carrier. Generated in a fan-shaped flame. Since each flame is small and burns in air, the formation of carbon black is very different from the lamp black production process (incomplete combustion). Here the carbon black particles are very fine, depending on the type, the average particle size is between 10 and 30nm, and the average particle size of gas black is 13nm. On the burning flame, there is a slowly rotating water-filled drum. Carbon black is deposited on the drum, and the carbon black is scraped away after being scraped. When the temperature is still high, the newly formed carbon black contacts with the oxygen in the air. As a result, partial oxidation occurs, forming a large number of acidic groups, and the corresponding pH value of the gas black is in the acidic range. And about 6% volatile matter can be obtained, representing its surface oxide content.
How is channel carbon black made?
This production process uses natural gas as raw material. The process of channel carbon black is similar to the gas combustion process of gas black production process. Natural gas burns and emits many fan-shaped flames. The obtained product is similar to gas black, but the difference is that the flat carbon black is used here The water-cooled U-shaped tank is used as a deposition tank for carbon black. The use of this method was discontinued many years ago for ecological and economical reasons. The production of gas black will not affect the ecological environment, and the gas black process is still in use.
How is Furnace Carbon Black Made?
Gas black is produced in the open atmosphere, but the furnace carbon black production process is carried out in a closed furnace under oxygen-deficient conditions. What is used is not many small fires, but a large flame, using oil as raw material, and adding combustible gas to bring it to the required temperature in the furnace. By changing the production process conditions of furnace carbon black, the required pigment black can be obtained. For example: under different conditions, carbon black can reach a wide range of average particle size, from 80nm to as small as 15nmj, and even to particles as small as gas black. But for the same particle size, there are still differences between gas black and furnace carbon black, mainly because of the different surface chemistry. Furnace carbon black products are relatively rough, with an average particle size of 40nm. In addition, when the furnace carbon black production process is used, a small amount of basic compounds or other additives can be added to change the aggregation degree and type of aggregates, so that high-structure or low-structure carbon black can be obtained.
What can carbon black do?
According to different uses, carbon black is usually divided into pigment carbon black for coloring, rubber carbon black for reinforcement, conductive carbon black for conductive agent and special special carbon black. Applicable industries include rubber, ink, paint, battery, sealant and other industries.