"You can say that carbon black is the result of a controlled incomplete combustion," explains Bernhard Schwaiger, Chemical Engineer and Vice President of Applied Technology Advanced Fillers at Degussa-Hüls.
Three different processes are used by Degussa-Hüls for the production of carbon black. The most dominant method, furnace black, is used for 98% of the world's carbon black production.
The furnace black method is a continuous process and uses liquid and gaseous hydrocarbons as feedstock and as a heat source. When natural gas is available, the liquid feedstock is sprayed into a heat source generated by the combustion of the natural gas and heated air. Because this happens at a very high temperature, the reaction is confined to a refractory-lined furnace – hence the name furnace black. After carbon black is formed, the process mixture is shock-cooled by injecting water. This also prevents any unwanted secondary reactions. Further process steps then separate the gas and carbon black.
This controlled process can be adjusted to produce various grades of carbon black, which differ in specific surface and structure. High surface grades, for instance, which have small primary particle sizes (smaller than 20 nanometer), are used mainly for pigmentation.
Mostly rubber
Carbon black is mainly used in the rubber industry and above all for the manufacture of tyres. Other applications include printing ink, coatings and plastics.
For some special applications carbon black is pelletized using naphthenic oils. These "oil-beaded carbon blacks" have the best properties for achieving the excellent dispersion needed for printing ink production. The high purity and consistency of naphthenic oils produced by Nynas Naphthenics makes our oils the first choice.
If carbon black is to be used for pigment blacks there is often a finishing treatment necessary to improve the surface of the particles. There are a number of different processes, the most common being oxidation.
High demands
"Our customers are requesting further improvements and despite the fact that carbon black has been produced for industrial uses now for more than one hundred years, we are continuously making improvements by developing innovative products for different applications," continues Bernhard Schwaiger.
"Now and then there are performance jumps," he says. "For instance, recently we have developed new and innovative carbon black grades for production of truck tyres with considerably reduced rolling resistance. This is a good example of how new carbon black grades can contribute to environmental protection."
"In addition to developing new grades, we are also continuously developing our production processes. There are many niches for carbon black, and there is no reason to believe anything other than that the need for carbon black will continue."
CARLO LASZLO