Carbon Black Fabrication Processes

Fabrication processes of carbon blacks all share the same principle controlled heat decomposition of hydrocarbon products. Such processes are essentially chemical, either thermo-oxidative or mere thermal decomposition, as described in Table 4.2. 

Thermo-oxidative decomposition Thermal decomposition Furnace black Gas black (Degussa process) Lamp black Thermal black Acetylene black Aromatic oils from coal tar or petrol distillates, natural gas Coal tar distillates, natural gas Aromatic oils from coal tar or petrol distillates Natural gas (or oils) Acetylene 

Liquid feedstock atomized and sprayed into the flame 

Flame from combustion ofgas combined with Water quench 

Carbon black manufacturing process for furnace black. 

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Particle production from a flame process, especially soot and carbon black fabrication, has a history that can be traced to prehistoric times [1]. For several years, Titania and sihca powder have been produced industrially via a flame process [2]. As a continuous process, the flame method allows production at a high rate with controlled-particle characteristics that result in an inexpensive process for powder fabrication [3]. In addition, the abihty to control the fuel flow rate in flame is useful because it provides some control over the temperature at which a reaction can be carried out [3-5]. Generally, the characteristics of flame-made particles are highly crystalline, dense and free of impurities due to the high-temperature flame heat. 

As discussed in Chapter 10, a wide variety of additives is used in the polymer industry. Stabilizers, waxes, and processing aids reduce degradation of the polymer during processing and use. Dyes and pigments provide the many hues that we observe in synthetic fabrics and molded articles, such as household containers and toys. Functional additives, such as glass fibers, carbon black, and metakaolins can improve dimensional stability, modulus, conductivity, or electrical resistivity of the polymer. Fillers can reduce the cost of the final part by replacing expensive resins with inexpensive materials such as wood flour and calcium carbonate. The additives chosen will depend on the properties desired. 

Fluorinated carbon, CFX, where x is between 0 and 1.3, is prepared by the direct fluorination of carbon at high temperatures [108]. Many varieties of fluorinated carbon can be prepared depending on the type of carbon used in the process (e.g. graphite, petroleum coke, carbon black, etc.) and the level of fluorination (i. e. the value of ). Fluorinated carbons, such as those manufactured by Allied-Signal (Accufluor ), Central Glass Co. (Cefbon ) and Daikin, are used for the fabrication of cathodes in lithium anode batteries and as solid lubricants [109]. 

Carbon blacks (c.b.s) have been known since ancient times, for preparing Indian ink. From the 1920s, c.b. has been fabricated industrially on a large scale by the thermal decomposition of hydrocarbons (natural gas) or aromatic hydrocarbons. Of the total production, 90% goes into the rubber industry, and most of this is employed for the reinforcement of tires. Production capacity is at present 7.2 million tonnes/y and the armual production is 6.1 million tormes/y [244] 95% of this global fabrication is by the furnace c.b. process [245]. The specific surface area As (nr/g) in this case covers a range from a few tens up to more than 1500. It should be mentioned that c.b. is used as a filler for conducting polymers [246]. 

The necessary porosity for thicker layers was introduced by appropriate current densities [321-323], by co-deposition of composites with carbon black [28, 324] (cf. Fig. 27), by electrodeposition into carbon felt [28], and by fabrication of pellets from chemically synthesized PPy powders with added carbon black [325]. Practical capacities of 90-100 Ah/kg could be achieved in this way even for thicker layers. Self-discharge of PPy was low, as mentioned. However, in lithium cells with solid polymer electrolytes (PEO), high values were reported also [326]. This was attributed to reduction products at the negative electrode to yield a shuttle transport to the positive electrode. The kinetics of the doping/undoping process based on Eq. (59) is normally fast, but complications due to the combined insertion/release of both ions [327-330] or the presence of a large and a small anion [331] may arise. Techniques such as QMB/CV(Quartz Micro Balance/Cyclic Voltammetry) [331] or resistometry [332] have been employed to elucidate the various mechanisms. 

Industrial carbon materials are used for molds, structural forms, electrodes of all kinds to be used in current production, metal deposition, and chemicals manufacturing [92]. Their fabrication involves a number of specific operations and processes. For instance, carbon blacks are deposited, collected, and processed. Cokes must be crushed and calcined binders (pitches) must be pulverized and classified. Green mixtures are formed, molded, extruded, baked, and some carbons are also graphitized to provide special properties. 

We now consider the interface between carrier and toner, as these components interact in a dynamic development system. As we have noted, toner is commonly fabricated by "jet impacting" a brittle pigmented thermoplastic to form irregularly shaped particles of about 12/u m cross-section--particles whose surface comprises resin and carbon black (2, J 3, 58). The carrier cores are magnetic (ferrite or steel), typically about 250/4 m in size and therefore relatively massive. They are generally coated with a dielectric oxide or resin, which participates in the tribo-electrification process (2, it , 59). ... 

The soils involved in cleaning processes can vary significantly (Table 8.2 [70]). The soils can either be solid pigments or a liquid phase like oils or fats. Usually they occur in mixtures, which may cause additional difficulties due to an interaction of the different soils. Difficult to remove soils, e.g. in the washing process of fabrics, are pigments such as carbon black or... 

Pipe and tubing are made from many materials, including metals and alloys, wood, ceramics, glass, and various plastics. Polyvinyl chloride, or PVC, pipe is extensively used for water lines. In process plants the most common material is low-carbon steel, fabricated into what is sometimes called black-iron pipe, Wrought-iron and cast-iron pipes are also used for a number of special purposes. 

Some work was done on the development of a process for the utilization of scrap rubber as feed for carbon black. Ground scrap rubber, presumably fabric-free, is heated with conventional carbon black feed stock oil, and the mixture utilized in a conventional furnace type carbon black reactor. Apparently, this process is not economically attractive. 

In the electrode fabrication process, the active materials are coated onto metal foils and calendered. The positive electrode consists of active material, such as LiCoOj, LiNiOj, or Li MnO a carbon-conductive agent such as acetylene black, Ketjen... 

Other successful electrochromic devices have been realized by Kelly et al. using polyaniline-impregnated fibres [79]. In situ electrochemical polymerization of polyaniline is used to bind poly aniline to a PET or viscose spacer fabric. The fabric is then impregnated with an electrolyte and sandwiched between two electrodes. For the bottom electrode, carbon black or silver ink can be printed directly on the fabric. Polyaniline colour changes from green to blue through oxidation—reduction processes. However, the lifetime of this structure is also short and does not exceed dozens of oxidation—reduction cycles. 

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