What is carbon black?
To find an answer to the question "what is carbon black" does not seem to be particularly difficult, and almost everyone thinks they know what carbon black (soot) is. However, if we are confronted with soot emissions from various sources in our everyday lives, for example from smoky smokestacks, from poorly configured heating facilities, from the exhaust fumes of some diesel vehicles or in autumn from burning fields and meadows... Yet there is an important reason why we ask the question "what is carbon black?"
Here, we do not want to address in more detail the abovementioned "soots" that emerge as undesired by-products as a result of burning carbonaceous materials. On the contrary: Here the conversation should be about industrial products manufactured on a large-scale for which the term carbon black has increasingly been naturalized--even in non-English speaking countries--and which we identify as carbon blacks to distinguish them from undesired soots. Such a conceptual distinction can already be found in many other languages. Multiple methods are used to produce carbon blacks. They can be precisely managed and facilitate the targeted, reproducible and consistent production of a variety of different types of carbon black. The various types are defined in more detail with specifications and fulfill the various requirements of different fields of application.
There are more than 100 individual types of carbon black with special property profiles on the market. It is easy to imagine that the soot accumulated as a combustion by-product is not generated under such conditions; for the most part it also contains various contaminants and can thus be easily distinguished from carbon black, as described below. Why are there so many different types of carbon black with different quality characteristics? Due to the wide variety of fields of application, there are various requirements depending on the intended use. For example, carbon blacks used to reinforce rubber in the manufacturing of tires and technical rubber products--the so-called rubber blacks-- meet requirements that differ from those for the so-called pigment blacks, which are necessary for - amongst other things - printing inks, toner, ink-jet inks and paints or are used for the UV stabilization of polyolefins. Carbon blacks that are suitable for conductive and antistatic polymer equipment are used in rubber and non-rubber fields. Thus, every type of carbon black must be tuned to the respective field of application. Those who use carbon blacks have precisely defined requirements for the quality they desire and consistency.
The various manufacturing methods and the respective raw materials used also contribute to product variety. The carbon blacks each have a property profile based on the manufacturing methods and process conditions. The most important manufacturing method is the furnace method; over 98% of the carbon black produced worldwide--in the range of over 6 mil. tons per year--are furnace blacks. Based on the method, a distinction is also made between gas blacks, lamp blacks, etc.