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Since the prebaked anode
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According to the conductive metal bar inserted into the anode from the upper part or the side part, the electrolytic cell can be divided into lower self-baking anodic cell and side self-baking anodic cell. The two are also different in the structure of the electrolytic cell, but the anode works continuously.The self-roasting anode is made of anode paste.The anode paste is added to the anodic aluminum box of such electrolytic cell, which is roasted into a carbon anode from bottom to top by relying on the high temperature of electrolysis. With its consumption, the paste from the top continues to work with the anode downward, so it can be continuous.Because of the great Fi pitch smoke generated by anodic paste in the process of self-baking, which caused serious environmental pollution, China banned the elimination of small self-baking anodic aluminum electrolysis cells in 2000
Pre-baked anode
The raw materials of pre-baked anode for aluminum production can be divided into aggregate and binder.The aggregate mainly includes petroleum coke and Zhejiang green coke.In order to reduce the cost and make full use of waste resources, the residual anode electrolyzed from the prebaking tank can also be used as the aggregate component in the production of the prebaking anode after treatment, but the amount of addition is generally controlled at about 20%.Prebaked anodes are mostly in intermittent operation. Each group of anodes can be used for 18~28 days.When the anode carbon blocks are consumed to about 25% of their original height, in order to avoid the steel claw melting, the old set of anode carbon blocks must be lifted out and replaced by a new set of anode carbon blocks, which are called "remnants".Because the pre-baked anode is easy to operate, has no asphalt smoke damage, is easy to operate mechanically and the electrolytic cell is large, so it is used in the new large aluminum plant and the transformation of the self-baked anode cell at home and abroad.
Anode carbon block for aluminum production not only conduct electricity but also take part in electrochemical reaction in the electrolysis of aluminum in large pre-baked tank.The anode quality has an important effect on the condition of electrolytic cell, grade of aluminum, anode consumption, electric energy consumption, current efficiency and environmental pollution.Therefore, the anode carbon block should be strictly required, the ash content should be as low as possible, the content of silicon, iron, nickel and vanadium should be strictly controlled, the resistivity should be low, the porosity should be low, the structure should be compact, and the anode carbon block should have high tensile strength, bending strength and low slag dropping rate.
Anode carbon block for aluminum production appearance requirements:
(1) The sticky filler on the surface of the finished product must be cleaned;(2) The oxidation area on the surface of the finished product shall not exceed 20% of the surface area and the depth shall not exceed 5mm;(3) The angular length of the finished product shall not be more than 100×100mm, the edge length shall not be more than 300mm, and the depth shall not be more than 60mm, and shall not be more than two;(4) The length of the crack in the rod hole or the edge of the hole shall not be greater than 80mm, and the connected crack shall not be allowed between the holes;(5) The depression depth on the bottom surface of the rod hole shall not be greater than 15mm, and the depression area shall not be greater than 2/3 of the bottom area (manual repair is allowed);(6) The length of large-surface cracks should not be more than 200mm, and the number should not be more than 3.
