Channel Blacks

Channel blacks such as the old EPC and MPC grades are acidic to neutral and can vary from having Httie effect to having a slight retardation in cure rate. The pH-neutral large-particle size MT thermal black generally has Httie effect on cure rate. 

Erom World War I to World War II the channel black process made most of the carbon black used worldwide for mbber and pigment appHcations. The last channel black plant in the United States was closed in 1976. Operations stiU exist and are even being expanded in Europe. The demise of channel black was caused by environmental problems, cost, smoke pollution, and the rapid development of od-fumace process grades that were equal or superior to channel black products particularly for use in synthetic mbber tires. 

The characteristics of roUer process impingement blacks are basically similar to those of channel blacks. They have an acidic pH, a volatile content of about 5%, surface area of about 100 m /g, and an average particle diameter of 10—30 nm. The smaller particle size grades are used as color (pigment) blacks, and the 30-nm grade is used in mbber. 

Also called channel black and furnace black. Chrome green. 

The formed soot collects on cooled iron channels from which the carbon black is scraped. Channel black is characterized by having a lower pH, higher volatile matter, and smaller average particle size than blacks from other processes. 

Rubber which is deliberately rendered electrically conductive by the inclusion in the unvulcanised mix of certain types of carbon black. Conductive rubber for use in, e.g., aircraft tyres has a resistivity below about 105 to 107 ohm-cm. The changeover from the use of channel blacks to oil-based furnace blacks has conferred a degree of conductivity (sometimes unwanted) on many black rubber products, and it should no longer be assumed that any black rubber is a good electrical insulator. See Antistatic Rubber. 

Channel Black Also called Gas Black. One of the processes used to make carbon black the others are the Acetylene Black, Fumace Black, Thermal Black, and Thermatomic processes. In the Channel Black process, natural gas was incompletely burnt in small flames, which impinged on cooled channel irons that were continuously moved and scraped. Invented by L. J. McNutt in 1892 and commercialized that year in Gallagher, PA. The last United States plant was closed in 1976. 

Furnace Black One of the three principal processes used for making carbon black the others being the Thermal Black and the Channel Black processes. In the Furnace Black process, aromatic fuel oils and residues are injected into a high velocity stream of combustion gases from the complete burning of an auxiliary fuel with an excess of air. Some of the feedstock is burned, but most of it is cracked to yield carbon black and hydrogen. The products are quenched with water. 

Lampblack The original process for making carbon black by the incomplete combustion of oils. Superseded by the Acetylene Black, Channel Black, Fumace Black, and Thermal processes. 

Both types of surface oxides are found on technical products. Rubber grade carbon blacks are produced in different processes. Channel blacks are made by cooling a flame on iron plates, the so-called channels. The resulting carbon blacks are acidic in character because an excess of air is present (25). In the production of furnace blacks, the fuel, mostly oil or natural gas, is burned with a limited supply of air. Thermal blacks are obtained by thermal cracking of the gas, which sometimes is diluted with hydrogen. In consequence, both types show weakly basic reaction in aqueous suspension. 

Wetting properties. A clean carbon surface is hydrophobic. Surface oxides provide sites of adsorption for water and other polar compounds. The more surface oxides there are, the more distinct is the hydrophilic behavior of the carbon. This was confirmed by Healey et al. (39) for graphitized carbon black, and by Kraus (40) and A. V. Kiselev and his group (41) for carbon black. Beebe and Dell (42) measured the sulfur dioxide adsorption on channel black and found an increase after oxidation at 600°. Further evidence for selective adsorption of polar compounds was provided by Gasser and Kipling (43). 

Synonyms Carbon activated carbon acetylene carbon decolorizing carbon actibon channel black furnace black thermal black gas black lamp black ultracarbon... 

This includes furnace black, colloidal black, thermal black, channel black, and acetylene black. 

Carbon black includes several forms of artificially prepared carbon, such as furnace black, channel black, lamp black, and animal charcoal. It is a finely divided form of carbon consisting of particles of extremely fine size. It is obtained by partial combustion (in 50% required air) of vapors of heavy oil fraction of crude oil in a furnace or by thermal cracking of natural gas. Carbon black is used in many abrasion-resistant rubber products including tire treads and belt covers. It also is used in typewriter ribbons, printing inks, carbon paper, and paint pigments. It also can be an absorber for solar energy and UV radiation. 

Channel black A form of carbon black produced from nafural gas by the channel process. 

CA 65, 8559(1966) (A novel expl compn suitable for blasting consists of a rod of A1 sponge 1 inch diam x 1 ft long which is wrapped in Al foil so as to enclose one end and the circumference. A suspension of 20 wt % channel black in liquid O is poured into the open end of the foil container to achieve absorption of O by the sponged Al. After inserting ail electric detonator, the open end is sealed with Al foil and the ensemble kept in liq O prior to insertion into a borehole in rock. Detonation shatters the rock evenly, producing considerable heat, but little smoke)... 

Champion powder 2 Cl48 Chanayaku 2 C148 Chandelon expls 2 C148 Channel black 2 C148 Chaoyaku 2 C148 Chapman expl 2 C148... 

Both processes are still used in industry for the production of carbon black. The channel black process, a process for making impingement blacks, has been used in the United States since the end of the 19th century. This process, which has now been abandoned because of economic and environmental considerations, used natural gas as raw material. A similar process for the production of impingement blacks, the Degussa gas black process, is still used today. 

Natural gas, which was previously the predominant feedstock for the production of channel blacks and furnace blacks in the United States, has lost its importance for economic reasons. Currently, only thermal blacks are produced with natural gas. However, natural gas is still the most important fuel in the furnace black process, even though the use of other gases and oils is also possible. In several patents recycled tail gas in combination with oxygen or oxygen-enriched air, has also been proposed as a fuel, but has not reached any commercial importance. 

The furnace black process is currently the most important production process. It accounts for more than 95 % of the total worldwide production. The advantages of the furnace black process are its great flexibility in manufacturing various grades of carbon black and its better economy compared to elder processes. The following comparison makes this apparent for similar grades of carbon black, the production rate of one flame is ca. 0.002 kg/h for channel black, ca. 0.2 kg/h for gas black, and ca. 2000 kg/h for a modern furnace black reactor. However, in spite of the more advantageous furnace black process, the production processes listed in Table 27 (except for the channel black process) are still in use for the production of special carbon blacks which cannot be obtained via the furnace black process. 

In the past decades the rapidly expanding automobile industry required increasing numbers of tires with various characteristics. This led not only to the development of new rubber grades, but also to the development of new carbon blacks required by the increasingly refined application processes and to the development of a new and better manufacturing process, the furnace black process. Unlike the old channel black process, this process allows the production of nearly all types of carbon black required by the rubber industry. It also meets the high economic and ecological requirements of our times. 

The channel black process, used in the United States since the late 19th century, is the oldest process for producing small-particle-size carbon blacks on an industrial scale. Originally, the first reinforcing blacks were also produced by this process. In 1961, the production of channel black was about 120 000 t. The last production plant in the United States was closed in 1976, due to low profitability and environmental difficulties. Natural gas was used as the feedstock. The carbon black yield was only 3-6%. 

In Germany, where natural gas was not available in sufficient amounts, the gas black process was developed in the 1930s. It is similar to the channel black process, but uses coal tar oils instead of natural gas. Yields and production rates are much higher with oil-based feedstock this process is still used to manufacture high-quality pigment blacks with properties comparable to those of channel blacks. The gas black process has been used by Degussa on an industrial scale since 1935. 

Due to production conditions, only gas blacks (and channel blacks) are covered to a certain extent with acidic surface oxides. Furnace blacks contain only small amounts of oxygen in the form of basic surface oxides. 

---