Industrial Carbon and Graphite Materials. Группа авторов
condensation, hydrogen transfer, and isomerization. It differs from COALIFICATION in that its reaction rate is faster by many orders of magnitude. The final pyrolysis temperature applied controls the degree of CARBONIZATION and residual content of foreign elements, e.g. at T ∼1200 K the carbon content of the residue exceeds a mass fraction of 90 wt%, whereas at T ∼ 1600 K more than 99 wt% carbon is found.
See: CALCINED COKE, COALIFICATION.
Catalytic Graphitization
Description
CATALYTIC GRAPHITIZATION refers to a transformation of NON‐GRAPHITIC CARBON into GRAPHITE by heat treatment in the presence of certain metals or minerals.
See: GRAPHITE, GRAPHITIZATION, NON‐GRAPHITIC CARBON.
Notes
CATALYTIC GRAPHITIZATION gives a fixed degree of GRAPHITIZATION at lower temperature and/or for a shorter heat treatment time than in the absence of the catalytic additives (or a higher degree of GRAPHITIZATION at fixed heat treatment conditions). Often it involves dissolution of CARBON and precipitation of GRAPHITE at the catalyst particles so that NON‐GRAPHITIZING CARBONS can be graphitized by this procedure.
See: CARBON, GRAPHITE, GRAPHITIZATION, NON‐GRAPHITIZABLE CARBON.
Char
Description
CHAR is a solid decomposition product of a natural or synthetic organic material.
Notes
If the precursor has not passed through a fluid stage, CHAR will retain the characteristic shape of the precursor (although becoming of smaller size). For such materials the term “pseudomorphous” has been used. Some simple organic compounds, e.g. sugar, melt at an early stage of decomposition and then polymerize during CARBONIZATION to produce CHARS.
See: CARBONIZATION.
Charcoal
Description
CHARCOAL is a traditional term for a CHAR obtained from wood, peat, coal, or some related natural organic materials.
See: CHAR.
Notes
CHARCOAL has highly reactive inner surfaces and low sulfur content. It has or has had, therefore, a variety of uses, e.g. in ferrous metallurgy and for gunpowder (minor uses: medical purpose and paint materials).
Coal‐Derived Pitch Coke
Description
COAL‐DERIVED PITCH COKE is the primary industrial solid CARBONIZATION product obtained from COAL‐TAR PITCH and is mainly produced in chamber or DELAYED COKING PROCESSES.
See: CARBONIZATION, COAL‐TAR PITCH, DELAYED COKING PROCESS.
Notes
COAL‐DERIVED PITCH COKE, although it exhibits a pregraphitic microstructure, has often a lower graphitizability than PETROLEUM COKE. Fractions of COAL‐TAR PITCHES (obtained by extraction or filtration) may form COKES with needlelike structures and have an improved graphitizability. The usually lower graphitizability compared to PETROLEUM COKE is due to an inhibition of mesophase growth because of chemical and physical differences of the cokes.
See: COAL‐TAR PITCHES, COKE, PETROLEUM COKE.
Coal‐Tar Pitch
Description
COAL‐TAR PITCH is a residue produced by distillation or heat treatment of coal tar. It is a solid at room temperature, consists of a complex mixture of numerous predominantly aromatic hydrocarbons and heterocyclics, and exhibits a broad softening range instead of a defined melting temperature.
Notes
The hydrogen aromaticity in COAL‐TAR PITCH (ratio of aromatic to total content of hydrogen atoms) varies from 0.7 to 0.9.
Coalification
Description
COALIFICATION is a geological process of formation of materials with increasing content of the element carbon from organic materials, which occurs in a first biological stage into peats, followed by a gradual transformation into coal by action of moderate temperature (about 500 K) and high pressure in a geological stage.
Notes
COALIFICATION is a dehydrogenation process with a reaction rate slower by many orders of magnitude than that of CARBONIZATION. Some specific reactions approach completion before others have started. The dehydrogenation remains incomplete. The degree of COALIFICATION reached by an organic material in the process of COALIFICATION increases progressively and can be defined by means of the measured C/H ratio and of the residual contents of oxygen, sulfur, and nitrogen.
See: CARBONIZATION.
Coke
Description
COKE is a solid high in content of the element carbon and structurally in the NON‐GRAPHITIC state. It is produced by pyrolysis of organic material, which has passed, at least in part, through a liquid, liquid‐crystalline, or solid state during the CARBONIZATION process. COKE can contain mineral matter.
See: CARBONIZATION, NON‐GRAPHITIC CARBON.
Notes
As some parts, at least, of the CARBONIZATION product have passed through a liquid, liquid‐crystalline, or solid state, the resulting NON‐GRAPHITIC CARBON is of the graphitizable variety. From a structural viewpoint, the term COKE characterizes the state of GRAPHITIZABLE CARBON before the beginning of GRAPHITIZATION.
See: CARBONIZATION, GRAPHITIZABLE CARBON, GRAPHITIZATION, NON‐GRAPHITIC CARBON.
Coke Breeze
Description
COKE BREEZE is a by‐product of COKE manufacture; it is the residue from the screening of heat‐treated COKE; the particle size is less than 10 mm. Generally, COKE BREEZE has a volatile matter of <3 wt%.
See: COKE.
Colloidal Carbon
Description
COLLOIDAL CARBON is a PARTICULATE CARBON with particle sizes below approximately 1000 nm in at least one dimension.
See: PARTICULATE CARBON.