Carbon Blacks

From ancient China to the high–tech era

Degussa

Carbon blacks, also known as pigment blacks, are manufactured by various high-tech processes in special reactors and are considered high-quality specialty chemicals. They are distantly related to soot. Nowadays the substances have hardly any properties in common, but they do share an ancient tradition. The early advanced civilizations in China and Egypt recognized the usefulness of soot and used it as an additive for dyes and inks. At that time it was difficult to come by, which was reflected in its price.

The mass production of carbon blacks started in the first half of the 20th century, in the wake of the expanding tire industry. Carbon blacks are used as reinforcing fillers to optimize the physical properties of tires and make them more durable. Even today, the tire industry uses around 85 per cent of the carbon blacks manufactured worldwide. The other 15 per cent are used mainly in the paint and varnish industry and for automobile or wood paint. High resolution output from modern photocopiers or printers would also be unthinkable if superfine ink additives had not been developed for industrial use.

The story of the carbon blacks of Evonik Industries AG starts in 1932 when one of its predecessors, Deutsche Gold- und Silber-Scheideanstalt (Degussa AG since 1980), became the majority shareholder in a company producing flame soot - August Wegelin AG in Kalscheuren, south of Cologne. Ernst Busemann, the commercial director at Degussa, had recognized the opportunities for growth presented by the booming market for tires and engineered the takeover. Two years later, the National Socialist Ministry of Economics approached Degussa and invited it to develop the production method for gas black which could be carried out without recourse to imported raw materials.

The background to this was the National Socialist policy of autarchy, which was intended to make Germany largely independent of supplies from other countries. The Degussa chemist Harry Kloepfer made a breakthrough in development in 1934 and industrial production commenced in the same year in the Degussa factory in Kalscheuren. The CK-3 process was the method Kloepfer had found to manufacture gas black which would make the German tire industry independent of imports from the US. Kloepfer had broken the American monopoly. The largest carbon black production plant in Europe is still in operation today in Kalscheuren where it was first produced.

Fundamentally there are three different manufacturing processes: the flame soot process, the Degussa gas black process and the furnace process. In the flame soot process, soot is created by the thermal-oxidative decomposition of oils; in the Degussa gas black process, saturated carrier gases are separated, and the furnace method is also based on the thermal-oxidative decomposition of oils. The three processes result in a wide palette of pigment blacks, which differ in the size of their particles, their structure, their surface and their surface chemistry.

Research into and production of carbon or pigment blacks today are the remit of the Chemicals Business Area of Evonik. Around 1.2 million tons of different product variants are manufactured annually at 18 sites.