ABSTRACT
The first product produced by flame hydrolysis was pyrogenic (or fumed) silica. It was developed during World War II by the German chemist Harry Kloepfer, driven by the need to find an alternative to carbon black based on local resources. As sand is available everywhere and Kloepfer had knowledge about the gas black process, he developed the idea of the flame hydrolysis of silicontetrachloride (SiCl4,made by carbochlorination of sand) to pyrogenic silica. Today, this process is known as the AEROSIL® process [1], invented in 1942 by Kloepfer [2]. The details of this process were published in 1959 and later [3, 4]. A simplified flow sheet of the flame hydrolysis process is shown in Figure 1.1.
