The production of Anthracite Calcination

I. Basic Knowledge of Anthracite Calcination
Anthracite, also known as coking coal, is a high-grade fuel. During calcination, the internal structure of anthracite molecules undergoes structural adjustments and chemical reactions, making it more combustible while reducing the amount of gas produced, thus increasing its calorific value and energy utilization rate. The anthracite calcination process mainly includes preheating, thermal decomposition, and coking, but some steps are not always necessary.

II. Steps Not Omitted

(I) Preheating: The natural anthracite is preheated. The temperature during preheating is approximately between 200℃ and 400℃, heating the anthracite to a certain temperature to evaporate surface moisture and achieve acidic and reducing conditions.

(II) Thermal Decomposition: Under high temperature and oxygen-deficient conditions, the preheated anthracite is rapidly decomposed to produce coke, volatiles, solid tar, and other products. The temperature is typically between 700℃ and 1300℃. (III) Coking: Under extremely high temperature conditions, the coke produced by thermal decomposition is reheated to further increase its calorific value and reduce the content of ash and volatiles.

III. Omitted Steps Different manufacturers employ different processing techniques during calcination, and the omitted steps vary. However, some manufacturers may omit the following steps when calcining anthracite:

(I) Reduction: In the preheating stage before calcination, some manufacturers may omit the reduction process and directly proceed to the thermal decomposition step. This may cause certain elements in the coal to oxidize at high temperatures, reducing the efficiency of the entire processing.

(II) Gasification: Some manufacturers may omit the gasification step and directly perform coking heating after coke formation. This may result in the inability to fully utilize the gas produced by volatiles, reducing the calorific value of the anthracite.

IV. Conclusion Calcination of anthracite can significantly improve its combustibility and calorific value; however, omitting steps unsuitable for specific needs may affect the calcination effect. Therefore, in actual production, it is necessary to select an appropriate processing flow based on different requirements.

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