Coal is a solid combustible mineral gradually formed by ancient plants buried underground and undergoing complex biochemical and physicochemical changes. Coal is a solid combustible organic rock, which is mainly formed by the biochemical action of plant remains, followed by geological action after burial. Generally speaking, coal refers to coal that is often said, including bituminous coal, lignite, anthracite and so on. Coal has a wide range of uses and can be summarized into three main uses according to its purpose: (1) thermal coal (2) coking coal (belonging to bituminous coal) (3) coal for coal chemical industry, mainly including coal for gasification, low temperature dry distillation Coal, coal for hydrogenation liquefaction, etc.
Coke is made by heating bituminous coal to 950-1050 ℃ under the condition of isolating air, and finally made through drying, pyrolysis, melting, bonding, curing, shrinking and other stages. This process is called high temperature coking (high temperature dry distillation). The coke obtained from high temperature coking is used for blast furnace smelting, casting and gasification. The recovered and purified coke oven gas produced in the coking process is not only a fuel with high calorific value, but also an important industrial raw material for organic synthesis.
Coke is mainly used in blast furnace ironmaking and blast furnace smelting for non-ferrous metals such as copper, lead, zinc, titanium, antimony, mercury, etc., and acts as a reducing agent, exothermic agent and column skeleton. The use of coke instead of charcoal in iron-making blast furnaces has laid the foundation for the large-scale modern blast furnaces and is a major milestone in the history of metallurgy. In order to achieve good technical and economic indicators for blast furnace operation, smelting coke (metallurgical coke) must have appropriate chemical and physical properties, including thermal properties during the smelting process. In addition to being widely used in iron making and non-ferrous metal smelting (metallurgical coke), coke is also used in foundry, chemical industry, calcium carbide and ferroalloy, and its quality requirements are different. For example, coke for casting generally requires large particle size, low porosity, high fixed carbon and low sulfur content; coke for chemical gasification requires less strength, but requires good reactivity and high ash melting point; coke for calcium carbide production requires Maximize the fixed carbon content.