The true density of petroleum coke calcined at 1300 ℃ is the main item to measure the quality of petroleum coke. Generally speaking, the higher the true density of petroleum coke calcined, the easier it is to graphitize, and the lower the resistivity and thermal expansion coefficient after graphitization. The bulk density of petroleum coke shows the compactness of coke structure, and is directly proportional to the mechanical strength. In addition to the bulk density of coke, the tap density is also related to the particle size of coke.

The resistivity of raw coke without calcination is very high, close to that of insulator. After calcination, the resistivity decreases sharply. The resistivity of petroleum coke is inversely proportional to calcination temperature. The resistivity of petroleum coke calcined at 1300 ℃ decreases to 500 μΩ· M.

The thermal expansion coefficient of petroleum coke mainly depends on the properties of residual oil, that is, the content of aromatics and asphaltenes in the residual oil. The thermal expansion coefficient of petroleum coke produced by residual oil with high content of aromatics and low content of asphaltenes and resins is low. Needle coke is such petroleum coke, and the thermal expansion coefficient of needle coke is also different (see Table 1), Needle coke with low coefficient of thermal expansion should be used in the production of large-scale ultra-high power graphite electrode and joint blank. The coefficient of thermal expansion of petroleum coke is related to the test temperature. The standard temperature for testing the coefficient of thermal expansion in China is 100 —— 600 ℃. The results obtained from different test temperatures can not be directly compared.

The mechanical properties of petroleum coke include "fragility", brittleness and wear rate. The "fragility" and brittleness of petroleum coke have a certain practical significance in the electrode manufacturing process. The fragility can be evaluated by the size ratio of coke before and after crushing, and brittleness is the possibility of coke crushing in the process of transportation and transmission. The wear rate of petroleum coke is directly proportional to its volatile content and inversely proportional to its bulk density. The wear rate of calcined petroleum coke decreases significantly.

To learn more about graphite fossil oil coke, pay attention to the official website of Linyi Yanjun Carbon Materials Sales Co., Ltd., welcome to inquire. Linyi Yanjun carbon material sales Co., Ltd. is the export and sales company of Linyi Lubei Carbon Co., Ltd Φ 150mm- Φ 600mm standard graphite electrode with ordinary power, impregnation, high power and ultra-high power. Tel: 15165931761