Carbon Black

 

Carbon Black is a commercial form of solid carbon produced by the incomplete combustion of hydrocarbons such as coal tar, vegetable matter, and petroleum products in highly controlled processes. It is characterised by a high surface area-to-volume ratio and is less crystalline than graphite. Carbon black typically contains more than 95% pure carbon with trace amounts of oxygen, hydrogen, and nitrogen. In simple terms, carbon black is essentially elemental carbon in the form of extremely fine particles with an amorphous molecular structure.

Uses of Carbon Black

Carbon Black is used extensively in various applications, including:

1. Reinforcement in rubber: Carbon Black is widely used as a reinforcing agent in tire components (such as treads, sidewalls, and inner liners), in mechanical rubber products, including industrial rubber products, roofing membranes, automotive rubber parts (such as sealing systems, hoses, and anti-vibration parts), and in general rubber products (such as hoses, belts, gaskets, and seals). In these applications, carbon black provides reinforcement and improves resilience, tear resistance, conductivity, and other physical properties.
2. Pigment and colorant: In addition to reinforcing rubber, carbon black is used as a black pigment in printing inks, paints, and plastics, providing high hiding power and great color depth. In the coatings industry, finely treated carbon black is a key to achieving deep black paints.
3. Conductive additive: Carbon black is also used as an additive to improve material performance, including conductivity, viscosity, static charge control, and UV protection.
4. Electrostatic discharge applications: Carbon black is added to rubber products for vehicles requiring anti-static properties, such as oil trucks and hospital carts.

Types of Carbon black

Carbon black is classified into several types based on its production method and properties. These different types meet specific industrial needs, from reinforcing materials in tires to pigmentation in inks and plastics. The main types include:

i. Furnace black: Produced by the partial combustion of hydrocarbons in a furnace at high temperatures (1200-1600 °C).

ii. Channel black: Made from the incomplete combustion of oils in a channel furnace, resulting in larger particle sizes. It is less commonly used today.

iii. Thermal black:  Produced by thermal decomposition of hydrocarbons at high temperatures without air. It has a lower surface area compared to furnace black and is a primarily used in application requiring lower reinforcement.

iv. Acetylene black: Produced from the thermal decomposition of acetylene gas. It has a very high purity and is known for its excellent electrical conductivity, making it suitable for specialized applications like batteries.

v. Lamp black: Historically produced from burning oils or fats in lamps, this type is less common today and is primarily used as a pigment.

Carbon Black Manufacturing Process

Carbon black is a product of incomplete combustion. It is the dark component of smoke. Carbon black processes begin with the production of smoke. In the process, the first step is to create an intensely hot combustion zone with a suitable fuel. Once combustion is complete, a hydrocarbon feedstock is injected into this zone in greater than stoichiometric quantities. With this injection, carbon black is produced. After feedstock injection, the reaction is stopped by injecting water or allowing the temperature to drop over time. The carbon particles thus produced are separated from the process gas or smoke stream by conventional means and pelletized to increase the bulk density.