Industrial Carbon and Graphite Materials. Группа авторов
in Dortmund and at Gleiwitz in Upper Silesia, and during the Second World War, they reached a maximum production of around 50 000 t per year. Gas blacks by this process were produced until 1976 for the tire industry; today they are supplied as worthwhile pigments for printing inks and paints.
In the meantime, the “furnace black process” developed in the United States in the 1920s was on the advance. This process is also based on aromatic oils from coal tar and petrochemical sources as raw materials. They are sprayed into a drum reactor, which is kept at temperatures of around 1500 °C by a direct gas heating, and pyrolyzed. With quenching and filtering of the pyrolysis gas, depending on the quality of the raw material oil and the required quality of the carbon black, 40–70 wt% carbon black can be obtained, relative to the oil used. A single reactor could produce around 30 000 t per year. Today, over 95% of all carbon black worldwide (more than 10 × 106 t per year) is produced according to this process.
3.6 History of Activated Carbon
Porous charcoals from wood and other biomaterials (plants, blood, bones) have been used since ancient times as medicine against stomach and intestinal troubles [10]. In the nineteenth century, an additional usage became decolorizing charcoals for crude sugar solutions. The first industrially activated carbons were Eponit decolorizing carbons, produced since 1909 by the “Chemische Werke Ratibor” according to patents of R. von Ostrejko by heating wood charcoal with steam and carbon dioxide in a special furnace [11]. In 1911, the Dutch company Norit N.V. started commercial activation of peat by using steam. In addition to this gas activation, “chemical activation” of charcoals from several carbon‐containing raw materials such as sawdust, coconut shells, peat, lignite, and bituminous coal by zinc chloride solution or acids are applied in European countries and the United States since the twentieth century to produce adsorbing carbons for gas masks, gas and water purification, solvent recovery, and many other purposes (e.g. molecular sieving of gas mixtures). The production rate grew to more than 1 × 106 t per year.
3.7 Development of Synthetic Graphite
As mentioned above, synthetic graphite substituted the natural one since the beginning of the twentieth century because of the growing demand of electric engineering. In 1895, the American Edward Goodrich Acheson (1856–1931) discovered the “crosswise graphitization” process of prebaked carbon bodies, composed of pitch coke or petroleum coke with coal‐tar pitch as carbonizing binder. These molded bodies are transformed into crystalline graphite by direct electric heating crosswise to their longitudinal axis up to around 3000 °C during about 2.5 weeks [12]. A faster process, i.e. completed in just one day, as devised by the American electrochemist Hamilton Young Castner (1858–1899) already in 1893, uses a lengthwise graphitization and became today the industrially favored alternative because of energetic and economic advantages.
During the twentieth century, graphite electrodes for electric arc furnaces for the production of electrosteel from scrap and prereduced iron pellets became the dominant application of synthetic graphite with a worldwide consumption of about 1 × 106 t annually. The share of electrosteel in the overall production of crude steel (>1 × 109 t/yr) grew to about 30%. Graphitic carbon anodes (non‐graphitized) are produced and used nowadays predominantly for the electrochemical production of aluminum from clay according to the parallel inventions in 1886 of the American Charles M. Hall (1863–1914) and the Frenchman Paul Louis Toussaint Héroult (1863–1914) with a growing annual rate of about 5.8%.
A pure form of graphite can be used as moderator in nuclear reactors. Firstly in 1942, the Italian physicist Enrico Fermi (1901–1954, 1938 Nobel Prize in Physics) and his American working group used such “nuclear graphite” in their pile at the University of Chicago for the first successful nuclear fission of uranium (235U) with neutrons as controlled self‐sustaining chain reaction. In the 1960s He‐gas‐cooled high‐temperature nuclear reactors (HTRs) were developed in the United States and the United Kingdom and in Germany as pebble‐bed reactor with spherical fuel elements with graphite shell and embedded carbon‐coated particles of radioactive fuel, e.g. uranium or thorium oxide or carbide. Raw material for this pebble‐bed nuclear graphite was inter alia a special low‐anisotropic (“isotropic”) coal‐tar pitch coke tested by longtime irradiation. A commercial pebble‐bed He‐gas‐cooled HTR went on stream at Hamm‐Uentrop (Westphalia) but then was turned off because of political reasons. After that since 2007, similar inherently safe nuclear reactors (core meltdown impossible!) were planned in China, South Africa, and Japan.
3.8 Development of Synthetic Diamonds
Synthetic diamonds were detected firstly in 1894/1895 by the French chemist Ferdinand Frédéric Henri Moissan (1872–1907, 1906 Nobel Prize) in a quenched 3000 °C hot iron melt [13] and then synthesized industrially from graphitic carbon only since 1955 by the high‐pressure process with “belt reactors” of the American physicist Percy Williams Bridgman (1946 Nobel Prize) by the American General Electric Company in a catalytic metal melt of carbon at 1200 °C and around 45 kbar [14].
In the years 1956–1977, the Russian scientists Boris Spitzyn and Boris Derjaguin detected the low‐pressure buildup of polycrystalline diamond layers by chemical vapor deposition (CVD) through thermal decomposition of organic carbon compounds onto diamond, silicon, or non‐carbide‐forming metal substrates [15]. This detection was industrially realized by several methods and companies.
3.9 Development of Carbon Fibers
The Englishman Joseph Wilson Swan (1828–1914) and his American competitor Thomas Alva Edison (1847–1931) constructed in 1878/1879 long‐life carbon filament electric light bulbs. The filaments were made by carbonization of cellulose fibers. In the 1950s, W.F. Abbott developed a process for carbonizing synthetic rayon into a fibrous material for insulation, filtration, and adsorption. In 1959, the American Union Carbide Corporation started the industrial production of those fibers predominantly for the reinforcement of phenolic resins for rockets and missile components. Since 1950, synthetic polyacrylonitrile (PAN) fibers were oxidized and heat‐treated to black fibers that could be carbonized, too. In the 1960s, flexible and high‐strength carbon fibers of various qualities were made from PAN and further processed to multifilament spun yarns, woven fabrics, and felts for reinforcement of plastics and carbon itself. In 1963, the Japanese Sugio Otani detected that some pitches from coal tar and petroleum are spinnable to pitch fibers, which can be carbonized to carbon fibers. In 1976, J.C. Lewis, L. Singer, and coworkers developed high‐modulus carbon fibers by spinning, carbonizing, and graphitizing of liquid‐crystalline mesophase pitch from coal tar and petroleum. Today, various types of carbon fibers predominantly from PAN are produced up to more than 40 000 t per year for reinforcement of lightweight plastic construction materials [16].
3.10 Discovery and Inventions of Nanocarbons: Fullerenes, Nanotubes, and Graphene
With the development of high‐resolution electronic microscopy and other modern analytical methods, some different nanocarbon forms were detected and synthesized [17]. Nano‐layers of CVD diamond were already mentioned above. The “buckyball” molecule C60 and higher molecular fullerenes were detected firstly in 1985 in a mass spectrograph by a research group of chemists at the American Rice University (Harold Kroto, Robert Curl, Richard Smalley). These authors won the Nobel Prize in Chemistry in 1996. In 1990 at Heidelberg, the German physicist Wolfgang Krätschmer (together with the American physicist Donald Huffman) firstly synthesized the C50 and higher fullerenes in an electric arc reactor and later transferred into an industrial scale by Hoechst AG. In 1991, the Japanese Sumio Iijima (NEC Corporation at Tsukuba) firstly detected carbon nanotubes as “elongated” form of fullerenes also in an electric arc reactor. They exist in different forms and structures, and many of them up to now are investigated for potential applications.
The newest invention in the field of nanocarbons is related to graphene, i.e. one‐atom thin single layers of graphite. In 2004, Andre Geim and Konstantin Novoselov