Needle Coke Powder Molding Process And Its Impact On The Performance Of Carbonization Products

Needle coke is one of most important raw materials in the carbon industry, its crystal grain appearance is the needle foliate and has the obvious fiber structure and the high anisotropic characteristic. The molding of needle coke powder is an emerging research direction. At present, the domestic studies pay attention to the molding of coal powder, the molding technology of needle coke powder mostly pauses in the laboratory stage. Therefore, the studies on the molding technology of needle coke powder has a huge promotion effect to the coke powder recycling and enhancing the economic efficiency of coking plant. In this article, the needle coke powder was used as raw material and the purified middle teperature pitch was used as binder agen. Under the effects of pressure and binder, the needle coke powder was molded into a ball on a manual oil compressor afer heat mixing. The appropriate coke powder molding condition was obtained by testing its strength, and we evaluted the quality of products obtained from carbonizing the ball by examining its properites.The single factor experiment and the orthogonal experiment indicated that the best technological conditions of molding into ball for needle coke powder is: the allocated granularity proportion of the coke powder was 3.5% 5-3 mm, 40.5% 3-1 mm, 32% 1-0.5 mm and 24% -0.5 mm; the binder was Tianjin middel-temperature refined asphalt, the molding ball pressure was 45Mpa and the holding time was 5min and the content of binder was 10%. Under the best conditions, the intensity and the compressive strength of the ball can separately arrive to 30.4/time (1m)-1 and 1035N/one.Through the analysis of polarized light microscope and scanning electron microscope of the carbonization ball, it found that increasing the binder content, the fiber structure of the product reduces about 6%, its porosity also relatively increases. After the carbonization, the overall quality of the product drops. Afer adding the binder, the true density of the product is 2.08g/cm3, the electronic resistivity is 10.15/μΩm , CTE is 1.9810-6.C-1.Through studying the ball pressure and the content of binder agent, it can obtain the bulk density, the electronic resistivity and the compressive strength of the product obtained by carbonizing the ball, thus can further evaluate the product quality. The experiment indicated that the molding ball pressure and the binder content has a critical value (in this experiment, is respectivley 45MPa and 10%). when the technology conditions exeeds the critical value, the carbonized product quality will be greatly affected, but its overall quality is better than that of pitch coke.