China's largest asphalt production base where
Coal tar pitch is a byproduct of coking, that is, the black material that remains in the distillation kettle after distillation of the tar. It is only fine with the physical properties of refined tar, there is no obvious boundaries, the general division method is to specify the softening point at 26.7 ℃ (cubic method) for the following tar, 26.7 ℃ above the asphalt. Coal tar pitch mainly contains volatile anthracene, phenanthrene, pyrene and so on. These substances are toxic, because the content of these components are different, the nature of coal tar pitch is also different. The change of temperature has great influence on coal tar pitch, which is easy to brittle in winter and easy to soften in summer. Heating with a special smell; heated to 260 ℃ in 5 hours later, it contains anthracene, phenanthrene, pyrene and other ingredients will be volatile.
Asphalt material is divided into asphalt and tar asphalt two categories. Asphalt is divided into natural asphalt and petroleum asphalt, natural asphalt is the oil exudation surface after long-term exposure and evaporation of the residue; oil asphalt is refined processing of residual oil residue, the appropriate process to deal with the product The Tar asphalt is coal, wood and other organic dry distillation processing of the tar after re-processing products. Most of the asphalt used in the project is petroleum asphalt, and petroleum asphalt is a mixture of complex hydrocarbons and their nonmetallic derivatives. Usually the asphalt flash point between 240 ℃ ~ 330 ℃, the ignition point than the flash point of about 3 ℃ ~ 6 ℃, so the construction temperature should be controlled below the flash point.
Oil asphalt is the residue after distillation of crude oil. According to the degree of extraction of different, at room temperature into a liquid, semi-solid or solid. Oil asphalt color black and shiny, with a high temperature. Because it is in the production process has been distilled to 400 ℃ or more, and thus contain little volatile components, but there may still be high-molecular hydrocarbons without volatile, these substances are more or less harmful to human health.
Asphalt is composed of different molecular weight hydrocarbons and non-metallic derivatives of dark brown complex mixture, is a high viscosity organic liquid, was liquid, the surface was black, soluble in carbon disulfide.
