What coal pitch (coal tar pitch)?
Coal pitch (coal tar pitch) is the residue after the liquid fraction is removed by distillation during the processing of coal tar. Coal pitch, a kind of artificial pitch, is a generally viscous liquid, semi-solid or solid.
What are the uses of coal tar pitch?
1. The fuel used, due to its high solid content, is generally mixed with heavy oil or made into powder for use, which can partially replace the role of heavy oil
2. It is used in the production of carbon electrodes. The carbon in coal pitch has a relatively high degree of graphitization. It can be used as an electrode material, as well as a sizing agent and a binder. There are many types of products in this regard, which involve a wide range of products. The main purpose of coal tar pitch.
3. Coatings are mainly used as waterproof coatings for buildings and pipes after processing. Epoxy coal tar paint is one of the most widely used.
4. Road construction and building materials are generally mixed with petroleum pitch. Coal pitch and petroleum pitch mixtures have obvious quality differences and shrink spacing. Coal pitch has poor plasticity, poor temperature stability, brittleness in winter, softening in summer, and rapid aging, and the mixed pitch performance is at least used alone. Among them, coal tar pitch is the most harmful, and too much of it is very harmful to the human body, and it will be more environmentally friendly if it is used after harmless treatment.
5. Needle coke, activated carbon, carbon fiber, and other high value-added products. Coal tar pitch has a high residual carbon value, graphitized components, and is easy to process. Needle coke and carbon fiber are high-end materials with high added value. Using coal tar pitch as a raw material is equivalent to turning waste into treasure.
6. Other uses such as oil felt
The performance of coal pitch
Coal tar pitch is the main component of coal tar, accounting for about 50% to 60% of the total. Generally at room temperature, coal tar pitch is a black brittle lump and shiny.
The chemical composition of coal tar pitch is mostly aromatic hydrocarbons with three rings or more, and it also contains heterocyclic compounds of oxygen, nitrogen, and sulfur, as well as a small amount of high-molecular carbon substances.
Classification of coal tar pitch
Low temperature asphalt: the softening temperature is 30-75°C.
Medium temperature asphalt: the softening temperature is 75-95℃.
High temperature asphalt: softening temperature of 95-125℃.
Modified asphalt: the softening temperature is 105-120℃.
Advantages of modified asphalt
Modified asphalt can be produced by normal pressure thermal polymerization method, pressurized thermal polymerization method, and vacuum flash evaporation method.
Coal pitch produced by high temperature thermal polymerization has the following advantages
1. High coking residual carbon value and high mechanical strength of the product.
2. The softening temperature is high, and the problems of summer transportation and long-distance transportation are easy to solve.
3. During the mixing and kneading process, the bitumen overflows less smoke and reduces environmental pollution.
4. Modified asphalt has high thermal stability and can improve the quality of carbon materials.