Research Of Improving Kneading Process Of Carbon Anode

In the process of carbon anode production for aluminium electrolysis, kneading process has an important impact on physical and chemical properties of the anode. In traditional kneading process, dry material (including aggregate and powder) of different size are mixed and preheated firstly, and then molten asphalt is added to knead. A moment later, paste with certain plastic is obtained. In this paper, on the basis of the traditional kneading process, author studied four kinds of innovation kneading mode(referred to as A, B, C and D mode), and made a system comparison of four modes with the traditional process. The main results are as follows.(1) With same process parameters and equipments, comprehensive physical and chemical properties of carbon anode by four kneading mode (A, B, C and D) are all superior to those prepared by the traditional kneading mode.(2) The D mode (asphalt was added with part of ball mill powder and then mixed with dry aggregate sufficiently, and finally the rest of the ball milling was joined to knead together) is the best kneading mode. Compared with A mode, D mode can make anode resistivity, thermal conductivity and thermal expansion coefficient of carbon anode have an average decrease of3.49%,4.09%and11.04%, and an average increase of air and CO2reactivity residual rate by more than1.6%. Compared with C mode, D mode can make anode bulk density, residual air reaction rate and compressive strength have an average increase of0.58%,0.9%and3.59%, resistivity and thermal expansion coefficient decrease by an average of3.95%and2.95%.(3) It is found that the ball milling premixed process is significantly better than the ultra-fine powder premixed process. Possibly because the ball milling powder premixed into the asphalt forms a hard-packed body with graduation structure, which is more suitable than the single ultra-fine one, in gaps of petroleum coke particles in kneading process.