Coal tar Pitch
The solid product processing of gas tar (yield 50-60% by weight). Similar in appearance, thermoplastic black material with a brilliant conchoidal fracture. The elemental composition (%): 92-93 C, 4,3-4,7 H, 0,3-0,85 S, 1,7-1,8 N, 0,8-1,0 O. Density 1.2 -1.3 g/cm3, ash content 0,2-0,3%. Has no definite melting temperature and solidification; melts in the range, which is characterized by softening. Distinguish medium temperature coal tar pitch (softening point 65-900C; flashpoint 200-250 0C; volatile substances formed in the thermodynamic expansion, 53-63% and high (respectively 135-150 0C; 360-400 0C; 43-54%). Raising the softening point is achieved by distillation of medium pitch with water steam or inert gases and air treatment.
For technological purposes, the most important, besides the density, the following properties of coal tar pitch: viscosity, surface tension, wettability, thermal stability, sinterability, and have the ability to make coke residue. For pitches with different softening these properties unequal and considerably depend on the quality of raw materials and preparation conditions.
The main components: multinuclear condensed aromatic and heterocyclic compounds, products of their polymerization and polycondensation. In coal tar pitch identified about 500 compounds, including benzoantratsen, benzopyrene, perylene, benzofluoreny, fluoranthene, naphthacene, chrysene, brazan and alkilbrazany, triphenylene, and others.
Because of the complexity of the chemical composition of coal tar pitch is usually characterized by group composition of its factions, which have different solubility in isooctane, toluene, and quinoline. Distinguished: a-fraction insoluble in toluene; b-fraction, insoluble in isooctane; g-fraction, soluble in all these solvents. In turn, a-fraction is separated into insoluble in quinoline and toluene (A1) and soluble in quinoline, but insoluble in toluene (a2). Limits for the content of a-and a1-fractions in different brands of coal tar pitch is regulated.
Coal tar pitch is spatially structured disperse system. For different pitches, dispersed phase, characterizing their sinterability, has relatively similar properties and structure, and dispersion medium, which are inherent plastic properties are quite different.
Coal tar pitch used to produce coke (ash content less than 0,25-0,50%) and pitch-binder used in the production of anode mass in the production of aluminum, electrodes and electrode rods, graphitized products, coalgraphitic blocks, etc.; for manufacturing briquetted coal fuel, rolled roofing, pitch plastic and paint for pipes corrosion protection, tanks, metal constructions, etc.
Mixture of coal tar pitch, coal tar oil and high-boiling fractions of coal tar get, so called, the prepared resin. In some varieties are introduced plasticizers (e.g., petroleum bitumen) and fillers (asbestos, slate, dolomite, mica or steatitic dust). These resins are used as impregnating and induviate mass in manufacturing of roofing materials and mastics, as well as pitch fibrous pipes, for the impregnation of paperboard, in the manufacture of talcous leather; as a component of epoxy-coal enamel for corrosion-resistant coatings, as a combustible mixture to highlight the flame in the open-hearth furnaces; as a raw material for the production of tar-dolomite converter refractories; resin mixtures from coal tar pitch with anthracene oil (or anthracene fraction), and pitch distillates are used as road-building material for the manufacture of accumulator tanks.
Coal tar pitch - toxic product; poisoning and skin lesions may be under the influence of dust and fumes of the molten product in contact with the coal briquettes; the allocation of volatile compounds from the anode, made on the basis of pitch coke, as well as under receiving. Maximum permissible concentration (MAC) for volatile compound 0.5 mg/m3.
Coal pitch peck granulated, GOST 10200-83.
Manufacturer: Avdeyevskiy, Yasinvosky and Dneprodzerzhinsk product plants.
Packing: bulk, big bags.
Weight of the car: at least 50 m.
Permissible deviation of the total supply: + / - 10%.