| 摘要 |
PURPOSE:To produce carbon electrodes for already fired type aluminum smelting with reduced content of metal impurities, by adding an inorganic fluoride to a specific stage in kneading a carbonaceous material consisting of aggregate and binder, molding the kneaded material and firing the molded material. CONSTITUTION:A suitable aggregate raw material is sieved or aggregate raw materials previously sieved to the respective particle size are incorporated at a specific proportion, and the resultant material is normally preheated. A carbonaceous binder is then added thereto, and the mixture is kneaded while heating and then molded and fired. In the above-mentioned series of steps, an inorganic fluoride, e.g. NH4F, NH4F.HF or AlF3, is added thereto before the molding step thereof. The time of adding the inorganic fluoride is not particularly limited if it is before the molding step, but preferably the inorganic fluoride is added in the kneading step, particularly in the kneading step of only the aggregate before adding the binder. The addition of the inorganic fluoride permits the reduction in content of metal impurities in the finally obtained already fired carbon anode. |
