| 摘要 |
Electrodes for use in the electrolytic reduction of aluminium comprise the carbide and/or boride of titanium having an oxygen impurity content in combined form less than 0.1% by weight of combined acid-soluble carbon when this is 0.4% by weight, and (0.1+0.04xN)% of oxygen when the carbon exceeds 0.4% by weight, where n=percentage by weight of acid soluble carbon. Preferably the electrode contains 2-40% of titanium carbide and in examples 10% is specified. The balance between O and C renders the electrode stable and less prone to penetration by molten aluminium. Nitrogen should not exceed 0.3% by weight of combined carbon at 0.4% up to 1% for carbon at 20%. Iron should not exceed 0.5% by weight. The ratio of total chemically combined oxygen, probably TiO2, to carbon-available, should not exceed 1:33. The electrodes are made from powdered materials, averaging 6m , which are then cold pressed and sintered, or hot pressed at 1800-2100 DEG C. The porosity should not exceed 10% by volume. Arrangements of the electrodes in furnaces are illustrated. Specifications 784,695, 784,696, 802,471, 802,905, 826,635 and 898,062 are referred to. |
