Pole changing method for prebaked-anode type cell

Abstract

The invention belongs to the nonferrous metal aluminum electrolysis technical field, in particular relating to a method for changing anodes of a prebaked anode cell provided with 28 groups of anodes 200kA. The method is characterized in that: 4 groups of anodes in the corner of the first row and the second row adopt single-anode replacement during the anode replacement operation, and 24 groups of anodes in the middle adopt double-pole combined replacement. Due to adoption of the replacement means of double-pole combined replacement, the frequency of anode replacement operation is greatly reduced, thereby the negative influence on the electrolytic cell is reduced; and then the energy consumption per ton aluminum and the production cost per ton aluminum are reduced. Simultaneously, the work efficiency is also improved; the gas collecting efficiency of the electrolytic cell is improved; and the discharge of harmful gas is reduced.

Description

1. Technical field [0001] The invention belongs to the technical field of non-ferrous metal aluminum electrolysis, and in particular relates to a pole changing method for a prebaked anode electrolytic cell with 28 groups of anodes of 200kA. 2. Background technology [0002] At present, China's aluminum output is close to 10 million tons, and its production capacity is close to 13 million tons, surpassing the United States for many years to rank first in the world. The domestic aluminum smelting method also adopts the electrolysis method, that is, the electrochemical reaction is carried out in the electrolytic cell to produce metal aluminum. At present, the electrolytic cells are divided into two types: pre-baked cells and self-baked cells. Self-baked cells have been gradually replaced by pre-baked cells due to high smoke pollution, low efficiency and high energy consumption. The cell types used in the domestic electrolytic aluminum industry are all prebaked anode electrolyt...

AI Technical Summary

Problems solved by technology

The following negative effects will occur during the replacement process: 1. After the anode is replaced, the original anode current distribution and magnetic field balance of the electrolytic cell are destroyed, and the duration of the cell voltage swing in the electrolytic cell is on average 10-40 minutes, resulting in The aluminum liquid in the tank fluctuates violently, which reduces the current efficiency and increases the unit power consumption per ton of aluminum

2. After replacing the new electrode, the current passing through the new electrode is almost zero in the first 12 hours; it can reach 80% of the normal level in 12-24 hours, and it can reach the normal level after 24 hours. The anode current of the original electrolyzer Both the distribution and the balance of the magnetic field are destroyed, which reduces the current efficiency and increases the unit power consumption per ton of aluminum

3. Since the slot must be opened to seal the aluminum alloy cover plate when the anode is replaced, the electrolysis fume will pollute the working environment, which not only affects the health of the electrolysis workers, but also reduces the purification efficiency of the flue gas and affects the surrounding environment of the factory

It can be seen from the above table that within a standard replacement period (the domestic average is usually 30-32 days), the electrolyzer needs to be replaced in sequence by 28 groups, and the number of pole changes is large, which has a great negative impact on the electrolyzer

Not only increases the unit power consumption per ton of aluminum, thereby increasing the production cost per ton of aluminum, but also aggravates environmental pollution

At the same time, it also increases the workload of workers and reduces work efficiency.