Study On Carbonization Behavior Of Coal Tar Pitch And Consolidation Strengthening Of Formed Coke

The technology of preparing formed coke with coke breeze as raw material and coal tar pitch activated by additive BJ as binder is of great practical significance for the recycling of coke powder.The carbonization consolidation of coal tar pitch binder is the key to the strength of the type coke,and there is still a gap between the strength of the type coke prepared by the existing technology and the high-quality metallurgical coke.In this study,the carbonization behavior of coal tar pitch under the action of additive BJ is studied in depth,and measures such as preferential selection of coal tar pitch and optimization of heat treatment system are proposed to strengthen the carbonization consolidation of formed coke,which provides technical support to realize the large-scale industrial application of formed coke technology.The BJ can reduce the aromatic ring condensation of coal tar pitch at room temperature,and the pre-oxidation process helps to generate phenolic compounds containing conjoined hydroxyl groups to promote the subsequent condensation reaction to occur,and the carbonation consolidation process is beneficial to the development of coal tar pitch crystal structure.The selection of binder coal tar pitch should give priority to coal tar pitch with high content of toluene insoluble matter and low content of quinoline insoluble matter;improvement of continuous temperature rise system can inhibit the thermal expansion effect of coal tar pitch carbonization process to some extent.The results show that under the condition of the coal tar pitch content is 12%,the additive BJ content is 2%,the forming pressure is 40 MPa,the pre-oxidation temperature is 370°C,the pre-oxidation time is 25 min,the pre-oxidation air velocity is 1.2 m/s,the carbonization temperature is700°C and the carbonization time is 30 min,the carbonization nitrogen flow rate is 50 ml/min,the compressive strength of the pre-oxidized sample is 14.71 MPa,and that of the carbonized sample is 26.57 MPa.The carbonization temperature is increased to 1000°C,and the compressive strength of the carbonization sample is increased to 30.83 MPa.The twostage heating system was optimized into a continuous step heating system.The compressive strength of the formed coke at 700°C was increased from26.57 MPa to 28.46 MPa,and the compressive strength of the formed coke at 1000°C was increased from 30.83 MPa to 32.48 MPa.The research on the consolidation structure and consolidation mechanism of formed coke shows that the graphitization degree of coke powder is higher than that of carbonized pitch coke.The carbonized pitch coke presents a three-dimensional network cross-linking distribution structure in the formed coke,and with the increase of carbonization temperature,its structure contracted,the crystal level showed more orderly arrangement,and the graphitization degree gradually approached that of coke breeze,but the final microcrystal size and graphitization degree of pitch coke were lower than that of coke breeze raw materials.